Congenital central hypoventilation syndrome and Hirschsprung's disease

Five cases of the Hirschsprung's disease-congenital central hypoventilation syndrome (CCHS) association are presented and 41 other published cases reviewed. These children have a distinct pattern of associated features, an equal sex incidence, and a characteristic spectrum of disease severity which suggests that the condition is genetically distinct from other cases of Hirschsprung's disease. While approximately 1.5% of Hirschsprung's disease patients, and 10% of those with total colonic aganglionosis, will have CCHS, up to 50% of CCHS patients will have Hirschsprung's disease. Approximately 20% of CCHS/Hirschsprung patients will also have neuroblastoma or ganglioneuroma, usually multiple. Abnormalities of the eye and autonomic nervous system are also common. The ventilatory abnormality is usually evident on the first day of life. The aganglionosis is also severe, with more than half (59%) of the patients having aganglionosis extending into the small bowel.

Lead foreign body ingestion in children

Foreign body ingestion is seen commonly in paediatric surgical practice and the vast majority of ingested foreign bodies will pass spontaneously once they have made their way into the stomach. Lead foreign body ingestion in children represents a special case in view of the potential for acute lead intoxication secondary to dissolution and absorption of the ingested lead. Lead dissolves poorly in physiological solutions with the exception of the acid environment of the stomach. We report a case of a 4-year-old child who ingested a lead sinker which was removed from the stomach by emergency endoscopy. This case stimulated a review of the relevant literature and the formulation of a management plan for lead foreign body ingestion in children. The principles of this management plan are observation of the child in hospital and use of a protein pump inhibitor until the foreign body has passed out of the stomach.

Analysis of stress levels among medical students, residents, and graduate students at four Canadian schools of medicine

PURPOSE

To assess stress in medical students, residents, and graduate science students at four Canadian schools of medicine.

METHOD

Four schools with different curricula in three different parts of Canada participated in the study: the University of Calgary Faculty of Medicine, the University of Alberta Faculty of Medicine, the Dalhousie University Faculty of Medicine, and the McMaster University Faculty of Health Sciences. All the medical students, residents, and graduate science students at each school were surveyed in 1994-95. The three instruments used were the University of Calgary Stress Questionnaire, the Social Readjustment Rating Scale (SRRS), and the Symptom Checklist-90. Demographic data were compared across all four schools. Analysis of variance was calculated for all test-item scores, utilizing a four (school) by three (program) by two (gender) design, which were all between subject factors. Significant main effects were followed up by using planned comparisons (Newman-Keuls, with a probability level of p < .05). Significant interaction effects were followed up by using an analysis of simple effects.

RESULTS

A total of 1,681 questionnaires were returned as follows: 621 of 1,304 (48%) from the medical students, 645 of 1,495 (43%) from the residents, and 415 of 829 (50%) from the graduate science students. There were significant differences between the three groups in the natures and degrees of stress, with the graduate students reporting higher levels of stress. There were significant gender differences as well, with the women reporting higher levels of stress. Overall, stress levels were found to be mild, based on the University of Calgary Stress Questionnaire and the SRRS.

CONCLUSION

This study suggests that medical students and residents experience stress at levels that appear acceptable, but ongoing monitoring and the provision of appropriate support systems will continue to be important.

Minor histocompatibility antigens

The existence of transplantation antigens, in addition to those encoded by genes in the MHC, has been known for over half a century. The molecular identification of these additional minor histocompatibility (H) antigens lagged behind that of their MHC counterparts, largely because minor H antigens are recognised by T cells and not by antibodies. In the past year, however, new minor H antigens have been identified at both the genetic and protein level and include Uty, a second novel gene encoding a male-specific epitope in mice, a novel autosomal gene encoding each of the H-13 alleles of mice, and a second male-specific epitope encoded by the SMCY gene.

Ectomesenchymoma: one or two tumors? Case report and review of the literature

Ectomesenchymoma has not previously been reported in a patient with the cutaneous nevus syndrome. A case of perineal ectomesenchymoma is presented with unusual cytogenetic findings. The significance of these is discussed and the world literature reviewed. This is the first such case reported.

Qa-1 interaction and T cell recognition of the Qa-1 determinant modifier peptide

The peptide-binding properties of the nonclassical major histocompatibility complex (MHC) class 1b molecule Qa-1 were investigated using a transfected hybrid molecule composed of the alpha 1 and alpha 2 domains of Qa-1b and the alpha 3 domain of H-2Db. This allowed the use of a monoclonal antibody directed against H-2Db whilst retaining the peptide-binding groove of Qa-1b. By comparison with classical MHC class I molecules, intracellular maturation of the chimeric molecule was inefficient with weak intracellular association with beta 2-microglobulin. However, at the cell surface the hybrid molecules were stably associated with beta 2-microglobulin and were recognized by cytotoxic T lymphocyte (CTL) clones specific for the Qa-1b-presented peptide Qdm (AMAPRTLLL). A whole-cell binding assay was used to determine which residues of Qdm were important for binding to Qa-1b and CTL clones served to identify residues important for T cell recognition. Substitutions at position 1 and 5 did not reduce the efficiency of binding and had little effect on CTL recognition. In contrast, substitutions at position 9 resulted in loss of MHC class I binding. Mass spectrometric analysis of peptides eluted from immunopurified Qa-1b/Db molecules indicated that Qdm was the dominant peptide. The closely related peptide, AMVPRTLLL, which is derived from the signal sequence of H-2Dk, was also present, although it was considerably less abundant. The mass profile suggested the presence of additional peptides the majority of which consisted of eight to ten amino acid residues. Finally, the finding that a peptide derived from Klebsiella pneumoniae can bind raises the possibility that this non-classical MHC class I molecule may play a role in the presentation of peptides of microorganisms.

An affect-management group for women with posttraumatic stress disorder and histories of childhood sexual abuse

Systematic research on effective treatment for survivors of childhood sexual abuse with posttraumatic stress disorder (PTSD) is virtually non-existent. The aim of the present study was to compare the effectiveness of an affect-management treatment (AM) group to a wait list control condition for female survivors of childhood sexual abuse with PTSD. Forty-eight female survivors of childhood sexual abuse with PTSD were randomly assigned to either a 15-week affect-management treatment group or to a wait list control condition. All subjects received individual psychotherapy and pharmacotherapy for the duration of the study, and for at least 1-month prior to the study. Controlling for pretreatment scores, subjects who completed the affect-management treatment group (n = 17) reported significantly fewer posttreatment symptoms of PTSD and dissociation than subjects in the wait list control condition (n = 16). Our findings suggest that an affect-management group treatment is beneficial as an adjunct to individual psychotherapy and pharmacotherapy for survivors of childhood sexual abuse with PTSD.

Porcine aromatases: studies on tissue-specific, functionally distinct isozymes from a single gene?

Aromatase cytochrome P450 (P450arom) is expressed in a variety of tissues. Pigs express P450arom as bilaminar blastocysts in utero, and thereafter in the gonads, adrenal glands and placenta. Our studies also demonstrate the existence of porcine isozymes of P450arom which differ substantially in their amino acid composition and function. The placental isoform, most similar to P450arom in other mammals, consists of 503 amino acids. The ovarian isoform, expressed in both theca and granulosa cells, is a 501 amino acid protein exhibiting less than 20% of the activity of the placental isozyme. Furthermore, it is inhibited not only by CGS16949A but also by etomidate which does not inhibit the placental P450arom. Partial sequences generated by the rapid amplification of the cDNA ends (RACE) procedure indicate that the expression of a third isoform in the blastocyst is switched to the placental isozyme during differentiation of the fetal membranes. In addition, these transcripts, and others from the theca, granulosa, testes, adrenal glands and placenta demonstrate differences in the 5'-untranslated region (putative exon I) suggestive of tissue-specific alternative splicing. An identical 5'-untranslated sequence was obtained from transcripts expressed in the theca and granulosa. Testes and adrenal transcripts also have identical 5' ends, which differ substantially from the ovarian sequence. Blastocyst and placenta 5'-untranslated sequences differ from each other and from those expressed in the gonads and adrenals. Several tissue-specific transcripts thus encode porcine P450arom. Interestingly, distinct 5' sequences exist for ovarian and testes P450arom mRNAs, suggesting different promoters and therefore regulation in the male and female gonads. The molecular origins of the functional isoforms and the tissue-specific transcripts are uncertain, however partial genomic sequence and other genetic analyses suggest the existence of multiple genes. However, sequence alignment of the placental and ovarian isoforms indicates complete conservation of putative exon III, so that complex splicing remains a possibility. Clearly, the regulation of P450arom expression is more complex in the pig than in other vertebrates investigated to date.

HLA genotype of patients with severe haemophilia A due to intron 22 inversion with and without inhibitors of factor VIII

Molecular genetic studies have shown that development of antibodies to factor VIII (inhibitors) occurs most frequently in patients with severe haemophilia due to major gene lesions including inversions, stop codons and large deletions. Previous studies of HLA type were performed on inhibitor and non-inhibitor patients with diverse uncharacterized mutations which may have confounded detection of significant associations. We therefore selected a group of patients with a single mutation type, the prevalent intron 22 inversion, with or without inhibitors, to determine HLA genotype. Seventy-one such patients, 42 without and 29 with inhibitors (13 high, 9 low and 7 transient responders) were genotyped for MHC Class I HLA-A, -B, -C and Class II HLA-DQA, -DQB and -DRB loci. No strong correlation of any HLA-allele to inhibitor or non-inhibitor status was found. However, alleles of the haplotype HLA-A3, HLA-B7, HLA-C7, HLA-DQA0102, HLA-DQB0602, HLA-DR15 occurred more often in inhibitor patients. Since the alleles of this extended haplotype are common in the North European population only a very strong association would achieve statistical significance. Further studies of groups of patients similar to those studied here will be needed to confirm or exclude this association.

Why do some females reject males? The molecular basis for male-specific graft rejection

The male-specific minor histocompatibility antigen H-Y plays an important role in both graft rejection and graft-versus-host disease following transplantation of male tissue into females that are completely matched at the major histocompatibility loci. The recent identification of two peptides that, in association with the mouse H-2Kk or human HLA B7 major histocompatibility class I molecules, are recognised by H-Y-specific T cells, has provided evidence for the molecular basis for such anti-H-Y responses. These peptides are encoded by the mouse and human homologues of a ubiquitously expressed Y chromosome gene, Smcy, whilst the equivalent peptides encoded by the X chromosome homologues of this gene fail to be recognised. Genetic studies have demonstrated that, as is the case for other minor histocompatibility antigens, peptide epitopes from several closely linked genes may be required to interact in order to elicit a response against H-Y. Definition of the peptides and the genes that encode these epitopes will allow the development of tolerogenic protocols that could specifically down-modulate the response to H-Y and perhaps even other minor histocompatibility antigens.

The male-specific histocompatibility antigen, H-Y: a history of transplantation, immune response genes, sex determination and expression cloning

H-Y was originally discovered as a transplantation antigen. In vivo primary skin graft responses to H-Y are controlled by immune response (Ir) genes mapping to the MHC. In vitro T cell responses to H-Y are controlled by MHC class I and II Ir genes, which-respectively, restrict CD8 and CD4 T cells: These can be isolated as T cell clones in vitro. T cell receptor (TCR) transgenic mice have been made from the rearranged TCR genes of several of these, of which that specific for H-Y/Db is the best studied. Non-MHC Ir genes also contribute to the control of in vitro CTL responses to H-Y. The Hya/HYA gene(s) encoding H-Y antigen have been mapped using translocations, mutations, and deletions to Yq in humans and to the short arm of the Y chromosome in mice, where they lie in the deletion defined by the Sxrb mutation between Zfy-1 and Zfy-2. Hya/HYA has been separated from the testis-determining gene, Sry/SRY, in both humans and mice and in humans the azoospermia factor AZF has been separated from HYA. In mice transfection of cosmids and cDNAs mapping to the Sxrb deletion has identified two genes encoding H-Y peptide epitopes. Two such epitopes, H-Y/K(k) and H-Y/D(k), are encoded within different exons of Smcy and a third, H-Y/D(b), by a novel gene, Uty. Peptide elution approaches have isolated a human H-Y epitope, H-Y/HLA-B7, and identified it as a product of SMCY. Each of the Hya genes in mice is ubiquitously expressed but of unknown function. Their X chromosome homologues do not undergo X inactivation.

An H-YDb epitope is encoded by a novel mouse Y chromosome gene

Rejection of male tissue grafts by genotypically identical female mice has been explained by the existence of a male-specific transplantation antigen, H-Y (ref. 1), but the molecular nature of H-Y antigen has remained obscure. Hya, the murine locus controlling H-Y expression, has been localized to delta Sxrb, a deletion interval of the short arm of the Y chromosome. In mice, H-Y antigen comprises at least four distinct epitopes, each recognized by a specific T lymphocyte clone. It has recently been shown that one of these epitopes, H-YKk, is a peptide encoded by the Y-linked Smcy gene, presented at the cell surface with the H-2Kk major histocompatibility complex (MHC) molecule. However, deletion mapping and the analysis of variable inactivation of H-Y epitopes has suggested that the Hya locus may be genetically complex. Here we describe a novel mouse Y chromosome gene which we call Uty (ubiquitously transcribed tetratricopeptide repeat gene on the Y chromosome). We identify the peptide WMHHNMDLI derived from the UTY protein as an H-Y epitope, H-YDb. Our data formally demonstrate that H-Y antigen is the product of more than one gene on the Y chromosome.

Improving the management of patients with schizophrenia in primary care: assessing learning needs as a first step

OBJECTIVE

To assess family physician learning needs related to the care of patients with schizophrenia.

METHODS

Questionnaires were mailed to all family physicians and general practitioners practising in southern Alberta. Physicians were asked to indicate the number of patients with schizophrenia cared for, their interest in improving the care the provided, their preferred learning methods, and the content they wished to learn.

RESULTS

A total of 539 surveys were returned for a return rate of 43.8%. Over half of the physicians (53.5%) indicated that they saw 1 to 2 patients with schizophrenia each month. Almost half (48.5%) indicated they were somewhat or very interested in increasing the care provided. Primary learning needs included increasing their knowledge of psychopharmacologic agents and monitoring and adjusting medications. Lectures and half-day workshops were the preferred learning methods.

CONCLUSION

Our study was helpful in identifying the types of education that physicians wanted as well as the duration of the programming prior to the development of teaching interventions.

The validation of the Trauma Symptom Checklist-40 (TSC-40) in a sample of inpatients

This study examined the construct validity of the Trauma Symptom Checklist-40 (TSC-40; Elliot & Briere, 1992) in a sample of 130 female psychiatric inpatients. Consistent with other findings, the TSC-40 displayed criterion-related validity in relation to childhood sexual abuse. Survivors of sexual abuse obtained significantly higher scores than those without such a history on the overall TSC-40 and on each of the six subscales, except the Depression subscale. Convergent validity of three subscales was demonstrated, and divergent validity on the total TSC-40 and each of its subscales was established. Further, among a range of abuse-effects measures, the Sexual Abuse Trauma Index (SATI) subscale was the most powerful predictor of sexual abuse. The SATI and Dissociation subscales were the subscales most sensitive to the specific features of the sexual abuse.

The long-term sequelae of sexual abuse: support for a complex posttraumatic stress disorder

This study examined the relationship between childhood sexual abuse and symptoms of a newly proposed complex posttraumatic stress disorder or disorder of extreme stress not otherwise specified (DESNOS). Compared to 34 women without histories of sexual abuse, 74 survivors of sexual abuse showed increased severity on DESNOS symptoms of somatization, dissociation, hostility, anxiety, alexithymia, social dysfunction, maladaptive schemas, self-destruction and adult victimization. In addition, a logistic regression found that a complex of symptoms representing DESNOS was significantly related to a history of sexual abuse. Consistent with other studies, the results of this study provide support for the idea that symptoms of DESNOS characterize survivors of sexual abuse.

The ultrasonic diagnosis of urachal anomalies

Seven cases of urachal anomalies are presented. The spectrum of the disorder and the criteria for ultrasound diagnosis are described. Six of seven cases were correctly diagnosed pre-operatively with diagnostic ultrasound, but one case with no cystic component was missed. The appearance of a fixed, midline, cystic, extraperitoneal swelling between the umbilicus and the bladder should suggest the diagnosis.

Acceptance of skin grafts between mice bearing different allelic forms of beta 2-microglobulin

Single amino acid disparities in MHC class I molecules can elicit transplantation responses. Since beta 2 microglobulin (beta 2m) is noncovalently associated with class I antigens on the cell membrane we investigated whether the single amino acid polymorphism at position 85 (Asp-->Ala) in the mouse beta 2m molecule can cause skin graft rejection. A B2mb transgene was introduced into CBA(B2ma) mice which subsequently expressed both forms of beta 2m. Skin from these CBA beta 2mb transgenic mice was not rejected by the parental CBA strain. Previous studies showed that cytotoxic T lymphocyte (CTL) responses directed against beta 2mb use H2Kb as a restriction element. We therefore produced mice expressing H2Kb and H2Ab as well as beta 2mb by crossing CBA.beta 2mb mice with either CBA.Kb (CBK) transgenic mice or C3H.SW mice and used these as skin graft donors for beta 2mb negative littermates. In both cases rejection of transgenic skin only occurred when mice had received both a beta 2mb graft and an H2-disparate allograft lying adjacent in the same site. Introduction of the male specific antigen, H-Y, as a helper determinant did not result in rejection of beta 2mb skin. Neither did two CTL determinants (P91A and beta 2mb) on the same graft complement one another to elicit a transplantation response. Prior immunisation with tissues expressing the beta 2m disparity alone did not generate in vivo or in vitro beta 2mb-specific CTL responses, suggesting that this single amino acid difference is not sufficient to elicit a CTL or helper T cell response.

The relationship between dissociative symptoms, alexithymia, impulsivity, sexual abuse, and self-mutilation

The overall purpose of the present study was to further our understanding of the mechanisms of self-mutilative behavior in a sample of female inpatients. The study found that self-mutilators (n = 103) displayed a greater degree of dissociative symptoms and alexithymia and a greater number of self-injurious behaviors, as well as higher rates of childhood sexual abuse, than nonmutilators (n = 45). In addition, the study found that among these variables, the number of self-injurious behaviors had the strongest relationship to self-mutilation. However, both dissociative symptoms and alexithymia were independently associated with self-mutilative behavior. Implications of our findings for clinicians and researchers are discussed.

Immunology: why the baby isn't thrown out

The reason the maternal immune system does not reject a foetus may involve the downregulation of T-cell receptors specific for paternal antigens. A similar mechanism may help explain the remission seen in autoimmune patients during pregnancy.