By P. Malir. University of Wisconsin-Whitewater. 2019.
In addition to possible defects in immune function dostinex 0.25mg without a prescription women's health clinic melbourne, one of the major genetic defects appears to be in the manufacture of ﬁlaggrin 0.5 mg dostinex sale women's health issues wikipedia, a protein that facilitates proper integrity and moisture content of the skin buy 0.5mg dostinex menopause yoga. Studies have also shown that breastfeeding offers signiﬁcant protection against developing eczema as well as allergies in general. In older or formula-fed infants, milk, eggs, and peanuts appear to be the most common food allergens that lead to eczema. In one study, these three foods were implicated in 81% of all cases of childhood eczema,6 while in another study 60% of children with severe eczema had a positive food challenge to one or two of the following: eggs, cow’s milk, peanuts, ﬁsh, wheat, or soybeans. One randomized, controlled trial found that in individuals with a positive reaction to eggs on a radioallergosorbent test, an egg-free diet was associated with improvement in the severity of eczema, with the greatest effect seen in those most severely affected. Elimination of milk products, eggs, peanuts, tomatoes, and artiﬁcial colors and preservatives results in signiﬁcant improvement in at least 75% of cases. After one year, 26% of patients with eczema were no longer allergic to the ﬁve major allergens (egg, milk, wheat, soy, and peanut), and 66% were no longer allergic to other food allergens. Elevated levels of antibodies against candida are common in atopic individuals, indicating an active infection. Furthermore, the severity of lesions tends to correlate with the level of antibodies to candidal antigens. The bottom line is that elimination of candida results in signiﬁcant clinical improvement of eczema in some patients. Probiotics Because the intestinal ﬂora plays a major role in the health of the host, especially regarding eczema, probiotic therapy is particularly indicated. Studies show that administration of the probiotic Lactobacillus rhamnosus alone or in conjunction with Lactobacillus reuteri to infants with eczema and cow’s milk allergy demonstrates significant reduction of the severity of eczema. In fact, several double-blind studies with evening primrose oil (typically using dosages of at least 3,000 mg daily, providing 270 mg of gamma-linolenic acid) did show beneﬁt. Several studies with evening primrose oil failed to demonstrate any therapeutic beneﬁt over a placebo. In the largest of these studies and the one with the highest- quality methods, no beneﬁt could be demonstrated for evening primrose oil. One is that ﬁsh oils contain primarily long-chain omega-3 fatty acids, which are further down the anti-inﬂammatory pathway, while evening primrose oil contains both omega-6 and omega-3 fatty acids and gamma-linolenic acid is at the beginning of the omega-3 anti-inﬂammatory chain. Some people, such as those with atopic disease, have poorer-functioning enzymes for the conversion to the anti-inflammatory prostaglandins. Botanical Medicines The use of botanical medicines in eczema can be generally divided into two categories: internal and external. Internally, licorice preparations can exert signiﬁcant anti-inﬂammatory and anti-allergic effects. These beneﬁts are perhaps best exempliﬁed in several double-blind studies featuring a licorice-containing Chinese herbal formula. In one study, 40 adult patients with long-standing, refractory, widespread eczema were randomized to receive two months’ treatment consisting of either the active formula or a placebo decoction, followed by a crossover to the other treatment after a four-week washout period. In addition, of the 31 patients completing the study, 20 preferred the active formula, while only 4 preferred the placebo. There was also a subjective improvement in itching and sleep during the active treatment phase. No side effects were reported, although many subjects complained about the poor palatability of the decoction. A family history of allergic disease such as eczema and asthma is a major risk factor. With regard to using licorice topically, the best results are likely to be obtained by using commercial preparations featuring pure glycyrrhetinic acid. Several studies have shown glycyrrhetinic acid to exert an effect similar to that of topical hydrocortisone in the treatment of eczema, contact and allergic dermatitis, and psoriasis. In one study, 9 of 12 patients with eczema unresponsive to other treatments noted marked improvement, and two noted mild improvement when an ointment containing glycyrrhetinic acid was applied topically. In another study, 93% of the patients with eczema who applied glycyrrhetinic acid demonstrated improvement compared with 83% using cortisone. It is also considered a risk factor for breast cancer, though not as signiﬁcant as the classic breast cancer risk factors: family history, early onset of menstruation, and late first pregnancy or no pregnancy. Noninvasive procedures, such as ultrasound, can help in differentiation, but at this time definitive diagnosis depends upon biopsy. Those who continued with little change in their methylxanthine consumption showed little improvement. Fiber A comparison between the diets of 354 women with benign proliferative epithelial disorders of the breast and those of 354 matched controls and 189 unmatched controls found an inverse association between dietary ﬁber and the risk of such disorders. There is an association between abnormal cell structure in nipple aspirates of breast ﬂuid and the frequency of bowel movements. The cause of this association is probably that the bacterial ﬂora in the large intestine transform estrogen into various toxic metabolites, including carcinogens and mutagens. Fecal microorganisms are capable of synthesizing estrogens as well as breaking the bond between excreted estrogen and glucuronate, resulting in absorption of bacteria-derived estrogens and reabsorption of previously excreted estrogen as free estrogen. Diet plays a major role in colon microﬂora, transit time, and concentration of absorbable metabolites. Vegetarian Diet Women on a vegetarian diet excrete two to three times more conjugated estrogens than women on an omnivorous diet. Bacterial beta-glucuronidase is a bacterially produced enzyme that breaks the bond between excreted estrogen and glucuronic acid. Probiotic supplementation has been shown to lower fecal beta-glucuronidase and may help improve bowel function as well. Reducing the total fat intake to 15% of total calories while increasing consumption of high-ﬁber foods has been shown to reduce the severity of premenstrual breast tenderness and swelling, as well as reducing the actual breast swelling and nodules in some women.
Special technologies are Micro Light buy dostinex 0.5mg on line pregnancy upset stomach, Egg Switch generic dostinex 0.25mg online women's health louisville ky, Zero Touch Switch buy 0.25 mg dostinex mastercard breast cancer yard decorations, Infrared Switch . Prevention of scoliosis is achieved with postural hygiene and proper building and use of the corset. Close attention must be paid to the development of the spine, in particular during school age and adolescence. In the pres- ence of an increase of the Cobb angle >30°, the surgical approach must be considered. Also, art 53 of leg- islative decree 151/2001 states that individuals who care for an individual with a disability, as per law 104/1992, do not need to work nights, and therefore can apply for a “nights on call exemption”. Parents can modify quantity and timing of nutrition according to periods of sleep, respiratory fatigue and increased need of cough assist; 4. They are allowed to increase ventilation pressures to a maximum of 25 cm water (H2O) and to increase the respiratory rate. Then they are taught that the inspiratory pressure can be increased to obtain good chest rise and that, however, pressure must be maintained <40 cm H2O. This is necessary to verify the patient’s health conditions, both respiratory and general. During the follow-up visit, which commonly takes 2–3 days, the main aspects are to: (1) consider the condition of the family, e. It is important to verify the presence of both hyper- and hypocapnia and the possible negative conse- quence of the latter . Moreover, it is important to remember that low SpO2 can indicate the presence of hypercapnia, but hypocapnia can easily go unrecognised without good monitoring. The decision to start support to maintain life in such a severe disease is very dif¿cult. Concern exists about the opportunity to prolong life with arti¿cial means and the risks of prolonging also the patient’s suffering without option of care. The decision as to whether to offer long-term ventilation to parents of such patients is dif¿cult and complex. Although the level of disability is very severe, it is dif¿cult to accurately “estimate” the patient’s quality of life. This was in stark contrast to 67 physicians who estimated these patients’ quality of life at 2. Notably, almost 80% of physicians felt that the decision to initiate long-term ventilation should rest solely with them rather than with the patient’s family. The critical question physicians must continually ask themselves is whether our patient’s quality of life and, in particular, the bene¿ts that he/she gains from being kept alive, is outweighed by the suffering experienced as a result of the underlying disease and its treatment. It is often very dif¿cult to make parents fully aware of their child’s condition, both at the time of diagnosis and upon ¿rst clinical symptoms. It is different after several years, as the child will change as the condition and its associated problems change, which are main- ly related to joint deformities. We give parents the opportunity to see movies of children affected by the same disease and putting them in contact with families in similar situations through direct contact and contact with family associations and social networks. Those children will suffer pain and have to deal with tubes, machines, alarms and panic situations. Frequently, they will not be able to walk, run, swim or jump; and some will not be able to speak or move at all. The child’s condition will change the parents’ and siblings’ lives as well, often leaving little free time – perhaps even no time to read a book or attend a medical visit. Singles with a child with such a severe condi- tion and who must work for living will be obliged to leave the child in the hospital. The majority of these children will suffer the disease with little treatment available, and some will probably die as a consequence. Nevertheless, such situations are part of life and our world; happiness and sadness do not depend exclusively on illness or wellness but lie in our hearts and in how we feel about each other, particularly about our needful neighbour. Affected children and their families are often happier and emotionally stronger than many other families and children we would consider “normal”, and this is independent of any physical problem. As the number of home-ventilated children is increasing in Italy and around the world, it is important that a new culture towards these diseases occurs, allowing all physicians, nurses, health workers and healthy people to interact with them with hope and compassion, hopefully in a less ostentatious society. Jardine E, Wallis C (1998) Core guidelines for the discharge home for the child on long term assisted ventilation in the United Kingdom. Appierto L, Cori M, Bianchi R et al (2002) Home care for chronic respiratory fail- ure in children: 15 years experience. Margolan H, Fraser J, Lenton S (2004) Parental experience of services when their child requires long-term ventilation. Kamm M, Burger R, Rimensberger P et al (2001) Survey of children supported by long-term mechanical ventilation in Switzerland. Fraser J, Mak Q, Tasker R (1997) Survey of occupancy of paediatric intensive care unit by children who are dependent on ventilators. Dhillon J, Frewen T, Singh N, Speechley K (1996) Chronic mechanical dependent children in Canada. Bertrand P, Fehlmann E, Lizama M et al (2006) Home ventilatory assistance in Chilean children: 12 years’ experience. Fauroux B, Sardet A, Foret D (1995) Home treatment for chronic respiratory failure in children: A prospective study.
With severe chronic sinusitis buy dostinex 0.25mg low price menstruation 9 days, the accumula- substantial necrosis of the rostral nasal passages and tion of caseous necrotic debris can cause destruction its associated bone (see Chapter 41) order dostinex 0.5 mg free shipping womens health group enfield ct. This degree of destruction is particularly com- A septum divides the nasal cavity into two halves buy 0.25mg dostinex free shipping womens health 042013, mon in Amazon parrots and African Grey Parrots each containing a rostral, middle and caudal nasal with aspergillosis sinusitis. Air that enters the mulation of debris in the infraorbital sinus can lead external nares is warmed and moistened by the to periorbital swellings (Color 22. On the ventral surface are just cranial and dorsal to the choanal slit, which of the palate and along the choana are numerous courses longitudinally in the dorsal oral cavity or roof caudally directed choanal papillae, which are most of the mouth. The choanae are separated into right pronounced in gallinaceous species but are also and left openings by the nasal septum or vomer bone. The paired entrances of the nasal cavity can be viewed with a rigid or flexible endoscope by directing Swollen, inflamed choanal tissues, with a sloughing it through the rostral end of the choanal slit (see of the protruding papillae, are common with upper Color 13). The choanal slit represents the incomplete respiratory tract infections (particularly chlamy- diosis),30 and secondarily infected with candidiasis in fusion of the two bony plates of the hard palate (see Color 8). Instead, air immunosuppressed states following prolonged ill- moves from the nasal cavity through the choana via ness, malnutrition or improper antibiotic admini- the choanal slit (oropharynx) and then into the rima stration. The configuration of the cho- diagnostic indicator of current respiratory disease, as anal slit varies with the species, but in all cases the they seldom regrow after sloughing. These carti- also become lodged in the choanal slit and cause laginous rings may calcify as the bird grows older. Some birds, like the Whooping Crane, have a trachea that ex- tends to the cloaca, where it doubles back and re- Trachea turns to the thoracic inlet before connecting to the The opening of the larynx, or rima glottis, is not syrinx. Other species (Helmeted Curassow) have a covered by an epiglottis as it is in mammals. The similar configuration, but the trachea courses subcu- laryngeal cartilages are reduced or absent. When a bird breathes, the mouth is closed and can be classified as tracheal, tracheobronchial or the mobile glottis seals with the choanal slit, allow- bronchial depending on the location of fusion of the cartilages. There are no vocal cords in the bronchial-type syrinx in which the last of the tra- larynx. The shape of the The trachea is loosely found on the right side of the syrinx and the sound it emits are controlled by the neck, ventral to the esophagus. The trachea courses bronchial muscles that attach to the syrinx, the first under the crop at the thoracic inlet and terminates bronchial rings and the bronchotracheal muscles, into the syrinx. It is the syrinx that serves as the which extend from the bronchus to the trachea. The syringeal mucosa contains bistratified squamous or columnar epithelium that is subject to squamous metaplasia and granuloma formation. The paired lungs lie dorsally in the thoracic cavity, extending from the first through the seventh ribs in Psittaciformes; however, the bounda- ries of the lungs vary, and they may extend to the ilia in some species. The lungs are attached dorsally against the thoracic ribs and vertebrae, where they fill the intercostal space throughout their margins (see Color 14). When removed, the coastal surface of the lung will have an impression of the vertebral ribs (costal sulci). The sixth rib creates the most caudal sulci in Psittaciformes (see Anatomy Overlay). There are frequent and inaccurate suggestions that the avian lung is fixed and not expandable. While changes in the size or position of the avian lung are limited, it is a dynamic organ that does undergo expansion and contraction during the respiratory cycle. Cytology is a useful technique to establish a clinical diagnosis (courtesy of Louise funnel-shaped ducts (infundibula), which lead to the Bauck). A long trachea and inflated air sacs produce a loud, booming, low-frequency sound. Bird Mammal No diaphragm Active diaphragm Pathology involving the syrinx is best diagnosed and Air sacs No air sacs treated when signs of disease are first recognized. If Communicating air capillaries Alveoli (blind sacs) a bird stops talking or has a voice change it should be Syrinx No syrinx evaluated immediately for lesions developing in the perisyringeal area (frequently aspergillosis). Pro- Complete tracheal rings Open tracheal rings gressive changes recognized clinically as dyspnea, No thyroid cartilage Thyroid cartilage coughing or tracheal discharge are more difficult to No laryngeal vocal cords Laryngeal vocal cords successfully resolve (Figure 22. At necropsy, granulomatous in- Chronic sinusitis may cause the globe of the fraorbital sinusitis was evident. Some cases will resolve when the sinusitis The bird was part of a backyard flock in is resolved (courtesy of L. New- Galliforme associated with symblepharon, castle disease virus was isolated from the infraorbital sinusitis and rhinitis. A vaccination program was initiated avian sinuses are not restricted laterally by in the flock. A herpesvirus that is serologically distinct from Pacheco’s disease virus has been iso- Color 22. In this case, the pharyngeal chronic sinusitis is associated with an in- mucosa is covered with necrotic tissue. Conjunctival scrap- provide supportive care, the client passed a ings collected for cytology and culture are feeding tube and delivered a liquid-based most useful in identifying an etiologic product. The client had passed the tube into long-term treatment with tylosin eye wash the trachea instead of the esophagus, re- and lincomycin/spectinomycin in the drink- sulting in asphyxiation (courtesy of Brett ing water or an ophthalmic solution con- Hopkins). The bird was in excel- ing over-the-counter medications in the lent overall condition and had blood-tinged water for ten days. The lungs were edema- and mucopurulent rhinitis were noted on tous and hemorrhagic. Cytol- ious gases and fumes from non-stick cook- ogy of samples collected from the masses ing surfaces can cause similar gross lesions indicated an accumulation of mixed gram- in the lung. This fungal infection was secon- (h), liver (l), ventriculus (v), cranial thoracic dary to aspiration of ingesta.
Screening of indigenous plant extracts is carried out from January to December dostinex 0.25 mg for sale women's health clinic baulkham hills, 1997 by agar disc diffusion technique cheap 0.5mg dostinex latest women's health issues. Extracts of 17 plants Amarantus spinosus cheap 0.25mg dostinex with visa menopause 49, Brassica napus, Cassia fistula, Cassia siamea, Clerodendrum siphonanthus, Crataeva nurvala, Emblica officinalis, Eugenia caryophyllata, Hydrocotyle asiatica, Ipomoea aquatica, Ipomoea reniformis, Momordica charantia, Piper betle, Pinus kesiya, Ricinus communis, Terminalia chebula, Tinospora cordifolia are tested 16 bacterial strains; five strains of Escherichia coli, 4 strains of Shigella and one strain each of Klebsiella aeruginosa, Plesiomonas shigelloides, Proteus morganii, Pseudomonas pyocyanes, Salmonella typhi, Staphylococcus aureus and Vibrio cholerae were isolated from human clinical specimens. It was found that by using 50% ethanolic extraction from four plants Cassia fistula, Momordica charantia, Piper betle and Terminalia chebula have an antibacterial activity on two to 14 tested bacterial strains. The essential oil of Pinus kesiya shows the antibacterial activity on 3 organisms and the plant Eugenia caryophyllata shows activity on 15 tested bacteria. Fifty percent ethanolic extract and watery extract of the remaining plants did not show any antibacterial activity. Anti-cholinesterase activities of some anthelmintic agents and some medicinal plants. A biochemical system for measurement of anticholinesterase activity of chemical agents and some reputed medicinal plants was established. Let-toke-gyi, antidysenteric medicinal plant which was found to contain high anticholinesterase activity, can therefore be considered as a potential anthelmintic drug. The purpose of the present study was to evaluate scientifically the antidiarrheal effect of Albizzia lebbeck by using castor oil-induced diarrheal mice model hence Albizzia lebbeck is widely distributed in Myanmar. The dried powder of seeds of Albizia lebbeck was extracted with absolute ethanol and was used to obtain 14. Dose dependent decrease in frequency, enteropooling and percent intestinal transit of castor oil-induced diarrhea in all 3 tested groups (i. The ethanolic extract of seed of Albizzia lebbeck cause relaxation of intestinal smooth muscle by possible mechanism of anticholinergic and antihistamine. General pharmacological screening test of the extract had shown no abnormal changes. The phytochemical analysis of the ethanolic extract of seed of Albizzia lebbeck and dried powder of seeds of Albizzia lebbeck showed they have alkaloid, flavonoids, polyphenol, glycoside, carbohydrate, steroid, saponin, resin. These findings suggested that ethanolic extract of seed of Albizzia lebbeck possessed significant antidiarrheal effect in castor oil-induced antidiarrheal mice model. The purpose of the present study was to evaluate scientifically the anti-diarrhoeal effects of Calotropis gigantea by using castor oil-induced diarrhoeal mice model. The dried powder of leaves of Calotropis gigantea was extracted with both water and 95% ethyl alcohol were used to obtain aqueous extract and 47. Dose dependent decrease in castor oil-induced diarrhoea in all 3 tested groups (i. The ethanolic extract of leaves of Calotropis gigantea directly cause relaxation of intestinal smooth muscle by an as yet unknown mechanism. The results indicated that there was no lethality up to 16g/kg body weight with both aqueous and ethanolic extracts. General pharmacological screening test of both aqueous and ethanolic extracts of Calotropis gigantea had shown no abnormal changes. The phytochemical analysis of both aqueous and ethanolic extract and dried leaves powder of Calotropis gigantea showed they have alkaloid, steroid, tannin, resin, glycoside, polyphenol, carbohydrate and reducing sugar. Among these constituents, alkaloid, steroid, tannin and reducing sugar may mediate the anti- diarrhoeal property of Calotropis gigantea extract. The purpose of the present study was to evaluate scientifically the antidiarrheal effect of rinds of Garcinia mangostana Linn. Dose dependent decrease in frequency, enteropooling and percent intestinal transit were found in all 3 tested groups receiving ethanolic extract (1g/kg, 2g/kg and 4g/kg) on castor oil-induced diarrhea. The phytochemical analysis of the ethanolic extract and dried powder of rinds of Garcinia mangostana Linn. These findings proved that ethanolic extract of rinds of Garcinia mangostana Linn. Khin Sunn Yu; Thaw Zin; Mu Mu Sein Myint; San San Myint; Myint Myint Khine; Hla Myint, Saw; Maung Maung Htay. In developing countries, the majority of people living in rural; areas almost exclusively use traditional medicines in treating all sorts of disease including diarrhea. It thus becomes important to identify and evaluate commonly available natral drugs as alternative to currently used anti-diarrheal drugs, in terms of both efficacy and safety profile. The objective of the present study was to determine the anti-diarrheal efficacy of Leik-su-shwe (Barleria prionitis L. A further study on antibacterial activity of these plants was carried out on common diarrhea-causing organisms by Agar Well diffusion methods. The plants were collected from Yangon and Mandalay areas and the dried powdered plant parts of wholeplants were extracted with distilled water. Serial dilutions of 3, 6 and 12g/kg of the extracts were administered to 3 groups of mice which have been induced by castor oil to produce experimental diarrhea. Other groups of mice include a negative control group receiving normal saline and a positive control group receiving the standard anti-diarrheal drug, loparamide. The anti-diarrheal activity was assessed by 3 main parameters, (1) the effect on castor oil induced diarrhea (number and type of stools passed), (2) the effect on castor oil inducd enteropooling (weight and volume of fluid accumulation), and (3) the effect on castor oil induced small intestinal transit (passage of charcoal meal). The present study signified the anti-diarrheal effect of the extracts and their potential usefulness in a wide range of diarrheal states, whether due to disorders of transit e. The purpose of the present study was to evaluate scientifically the antidiarrheal effect of Aegle marmelos Linn. The dried powder of roots of Aegle marmelos (Ok-shit) was extracted with absolute ethanol and obtained ethanolic extract yield 3. Aegle marmelos root extract 1g/kg, 2g/kg and 4g/kg body weight produced significant dose-dependent decrease in castor oil (10ml/kg) induced frequency of diarrhea, enteropooling and small intestinal transit of mice. In isolated rabbit intestine, significant dose-dependent intestinal smooth muscle relaxation was found with Aegle marmelos root extract 5μg/ml, 10μg/ml and 20μg/ml bath concentrations. But, the possible mechanism of relaxation of intestinal smooth muscle has not been definitely known in this study.
Cytokeratin promoters are available and target transgene expression to speciﬁc cell layers of the epidermis buy 0.25mg dostinex with amex breast cancer markers. Experiments of this type can be useful as an aid to designing and testing efﬁcacy of therapeutic gene targeting strategies buy generic dostinex 0.5 mg on-line women's health center mason city ia. Unfortunately safe 0.5mg dostinex womens health neenah wi, current gene deliv- ery systems fall short of this rate of transduction. Relative to transgenic approaches, clinically relevant questions may be: What are the consequences of gene transfer and expression in 1, 5, or 10% of the target cell population? Will these levels of transduction restore function to a genetically deﬁcient tissue or organ? Can expres- sion of the therapeutic gene in one cell beneﬁt a neighboring nontransduced cell, that is, are there juxtacrine, paracrine, or endocrine effects of foreign gene expres- sion or are transgene effects strictly cell autonomous? These questions can be addressed by creating chimeric tissues, which are composed of two genetically dis- tinct cellular populations in variable proportion to one another. Embryo aggregation is performed by physical aggre- gation of two distinct preimplantation embryos at the 4- to 8-cell stage, followed by transfer of the chimeric embryo to the oviduct of a pseudopregnant recipient mouse. In either case, the two populations of cells can associate with one another and develop into a chimeric mouse, which possess in each tissue a variable propor- tion of the two donor genotypes. By manipulating (or selecting for) the level of chimerism in each animal, it is possible to identify the phenotypic effect of a minor- ity population of cells of one genotype upon the majority of cells of a second geno- type. For example, the therapeutic consequences to the cftr-null mouse chimeric with 5% of cells with normal cftr genes could be addressed using this approach. Analysis is facilitated by marking one or both genotypes with reporter genes so that each genotype can be precisely localized in microscopic tissue sections. A related approach involves reconstitution of a tissue by cell transplantation using a mixed population of donor cells of two genotypes. Both mammary gland and liver can be reconstituted as chimeric organs using transplantation of mammary epithelial cells into the caudal mammary fat pads or of hepatocytes into the portal vein. Chimera analysis is being used more frequently to ask fundamental biological questions regarding cellular interactions. It also can be a powerful technique for evaluating the clinical effects of incomplete transduction of a target cell population in a patient. The tissues studied are of murine, not human, origin, and these do not always reproduce a model of human disease. A unique model to study human pathology in animals as well as murine/human biochemistry and physiology is the chimeric animal. Chimeric animals possess either cells, tissues, or organs derived from human stem cells, but limitations in these animals result from inter- actions with systemic autologous growth factors and other biological molecules on cells. Chimeric animals can be generated through xenotransplantation, the transfer of tissue from one species into another species. Xenotransplantation broadens the range of experimental manipulations and tissue samplings that can be performed relative to using human subjects. The principal factor limiting xenotransplantation is immune rejection, the destruction of donor tissue by the host immune system. Xenotransplant recipients have been rendered immunodeﬁcient by irradiation, drug therapy, or surgical thymectomy in an attempt to inhibit the rejection process. The more commonly used immunodeﬁcient mouse strains include the nude, scid, and beige genotypes. More recently, targeted mutations in genes involved in B- and T-cell development have produced new models of immun- odeﬁciency that resemble scid mice. Because scid mice display a major immune defect, they provide a unique biological setting that can be used to address major questions in the ﬁelds of gene therapy and xenotransplantation. This phenotype is the result of expression of a recessive gene mutation maping to mouse chromosome 16. The scid mutation results in defective rearrangement of immunoglobulin and T- cell receptor genes during differentiation of the respective cell lineages, thereby blocking the differentiation of B- and T-lymphocytic lineage committed progenitors. Older scid mice express leakiness and produce a small amount of murine immunoglobulin. The immune phenotype also can be inﬂuenced dramatically by genetic background, age, and microbial ﬂora, complicating comparisons of experimental outcomes among different laboratories. A fade-out use of immunodeﬁcient mice has been as a repository for human tissue, particularly human tumors. Both nude and scid mice can support transplantation and growth of a variety of human tumors. However, nude mice will not support the growth of all tumors grown in scid mice, possibly due to the presence of competent B cells in nude mice. The adopted transfer of human cells is followed by a period of growth and expansion with experimental manipulation in a manner not possible with human patients. Speciﬁc gene therapy protocols, employing varying target genes and delivery vehicles, can be systemati- cally evaluated for efﬁcacy directly on human tissue in an in vivo setting. More sophisticated manipulations using immunodeﬁcient mice also have been performed. The engraftment of a functional human immune system into scid mice has provided a powerful tool for studying the role of the human immune system in cancer, autoim- munity, and infectious disease. Several protocols involving engrafting thymus, liver, bone marrow, cord blood, and/or peripheral blood lymphocytes have produced xenotransplant models where engrafted human hematopoietic cells reconstitute a human immune system in the mouse.