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Biomedical subjects

G Morgan

Publications and source records attributed to G Morgan.

At least 181 records · Page 10Linked to original sources
PubMed1994

Autosomal recessive proximal spinal muscular atrophy in 101 sibs out of 48 families: clinical picture, influence of gender, and genetic implications.

We analysed the clinical picture of 101 sibs (43 sib pairs, 5 triplets) with autosomal recessive proximal spinal muscular atrophy (SMA). Linkage data of 20 sibships, which were available for analysis, were in agreement with chromosome 5q linkage. The patients were classified according to the motor development into SMA I (never sat), SMA II (sitting without support), and SMA III (walking without aids). Three sibs with adult onset (> 30 years = SMA IV) were discussed as a separate entity. Age-of-onset of the 101 patients showed a wide spectrum (prenatal to 47 years). Among sib pairs with SMA I and SMA II the ages-of-onset appeared to be very similar except of one atypically discordant sib pair. With regard to SMA III, 3 out of 13 sibships (23%) showed a marked variation in age-of-onset ranging from 5-15 years within a family. Concerning acquired motor development (ability to sit and walk), 7 sibships (15%) belonged to different SMA types. Ages of death in 29 sib pairs in whom at least one sib had died before the age of 20 years were strikingly discordant. Neither the degree of disability nor the respiratory deficits are reliable predictors of life expectancy. Although a predominance of males can be observed, no significant effect of gender has been established in familial cases. The existence of multiple allelism seems to be the most suitable explanation for the high interfamilial variability considering the clinical concordance in most affected sib pairs.

Adolescent↗
PubMed1994

Membrane dynamics during migration of placental cells through trophectodermal tight junctions in sheep and goats.

Binucleate cells in ruminant trophectodermal epithelium are unique in that they form part of the tight junction as they migrate across it, maintaining the ionic barrier seal to the internal milieu of the fetus. Such participation imposes considerable constraints on the cell migration because membrane cannot flow through a tight junction. We report quantitative ultrastructural immunocytochemical evidence for vesicle membrane insertion into the binucleate cell plasmalemma which allows the cells to form a pseudopodium past the tight junction. This pseudopodium increases continuously in area by vesicle insertion and develops a close apposition to the plasmalemma of the fetomaternal syncytium which constitutes the fetomaternal boundary in the placenta of the sheep and goat. Eventually the apposed membranes of the binucleate cell pseudopodium and the syncytium fuse by vesiculation and the cytoplasm and nuclei of the binucleate cell merge into the fetomaternal syncytium. The binucleate cell plasmalemma remaining on the trophectodermal side of the tight junction is blebbed off into, and phagocytosed by, the uninucleate trophectodermal cells between which the binucleate cell passed. This process permits the delivery of the binucleate cell granules to the maternal side of the placenta but none of the fetal molecules expressed on the plasma membrane of the binucleate cells are exposed to potential maternal immunological rejection.

Animals↗
PubMed1994

Lymphocyte subpopulations, interleukin-2 and interleukin-2 receptor expression in childhood nephrotic syndrome.

Abnormal T lymphocyte function and reduced interleukin-2 (IL-2) production have been implicated in the pathogenesis of the nephrotic syndrome (NS). We investigated: (1) lymphocyte subpopulations and expression of IL-2 receptor (IL-2R) on T cells using two-colour flow cytometry, (2) serum IL-2 and (3) the soluble component of IL-2R (sIL-2R) in serum, using enzyme-linked immunosorbent assay, in 38 children with NS. All children, except those in remission, had marked proteinuria. They were divided into groups according to renal pathology: (1) steroid-sensitive NS (SSNS) not receiving prednisolone therapy, (2) SSNS on prednisolone, (3) focal segmental glomerulosclerosis (FSGS), (4) SSNS in remission and not receiving prednisolone therapy, (5) congenital NS (CNS). Results were compared with 26 age-matched controls. Total T lymphocytes (CD3) were reduced in groups 1 and 2; CD4 count was reduced in groups 1-4; CD8 count increased in groups 2 and 3; CD8 and CD19 (B lymphocytes) were significantly reduced in group 5. Increased IL-2R expression (CD25) on CD4 lymphocytes was noted in groups 1, 2 and 3 implying activation of these cells. In patients with SSNS, increased serum sIL-2R was recorded during relapse (1,273 +/- 497 U/l vs. 913 +/- 401 U/l in remission, P < 0.005) but free serum IL-2 was not detectable at any stage. The specific alterations in lymphocyte subpopulations in SSNS and FSGS would imply an involvement of the immune system distinct from that in CNS.

Acute Disease↗
PubMed1994

Identification of deletions in the btk gene allows unambiguous assessment of carrier status in families with X-linked agammaglobulinaemia.

Mutations within the btk gene have recently been shown to cause X-linked agammaglobulinaemia (XLA). Altered patterns of DNA restriction fragments are seen by Southern blot analysis of DNA from affected patients with deletions in the btk gene. We have identified seven affected families in which altered restriction fragments can be used to diagnose and confirm the carrier status of female relatives of affected boys and in prenatal diagnosis.

Agammaglobulinemia↗
PubMed1994

Lymphoproliferative disease after pediatric liver transplantation.

Posttransplant lymphoproliferative disease (LPD) is a serious complication, associated with considerable morbidity and mortality. Herein the authors report their experience with LPD in a series of pediatric liver recipients (from 1986 to 1993). A total of 95 transplants were performed in 78 patients. Only the 66 patients who survived at least 30 days were included in the analysis. There were seven cases of LPD (incidence, 10.65). Seven of the 43 patients who received OKT3 had LPD, compared with none of the 23 patients who did not receive OKT3 (P < .05). The total cumulative dose and the duration of therapy both correlated with occurrence of LPD. However, the dose per kilogram did not correlate with the development of LPD. The median time from transplant to diagnosis was 90 days. All cases were immunoblastic B-cell lymphomas, and all tumors were positive for the Epstein-Barr viral genome (EBV). Four patients never treated for LPD died; it was discovered incidentally during autopsy in two, during retransplantation in one, and within 5 days of death in one. The other three were treated with decreased immunosuppression, acyclovir, gamma globulin, and alpha-interferon. All three were cured of LPD, but one died of neurological complications after retransplantation. LPD may be interpreted as a symptom of a chronically overimmunosuppressed state, associated with a high mortality, from a variety of causes. LPD should be suspected for any patient whose clinical condition is deteriorating with no clear evidence of rejection, and should lead to a decrease in the amount of immunosuppression used.

Cause of Death↗
PubMed1994

Congenital absence of the portal vein: two cases and a proposed classification system for portasystemic vascular anomalies.

Congenital absence of the portal vein (CAPV) is an unusual condition that often is associated with other anomalies. This is the first report of reduced-size liver transplant in a patient with CAPV. Because the presence of this rare congenital portasystemic shunt, there was no portal-systemic pressure differential, and thus an absence of collateral vessels in the pretransplant state. As a result, surgery was complicated by severe mesenteric edema caused by an increase in portal pressure when the allograft was implanted. The morbidity associated with CAPV usually results from associated conditions, but if transplantation is necessary, careful management of mesenteric congestion is crucial to success. The authors' experience and a review of the literature indicate that the CAPV can be classified into one of two groups of portasystemic anomalies.

Abnormalities, Multiple↗
PubMed1994

Bone marrow transplantation for autosomal recessive osteopetrosis. A report from the Working Party on Inborn Errors of the European Bone Marrow Transplantation Group.

The outcomes of 69 patients who received allogeneic bone marrow grafts for autosomal recessive osteopetrosis in the period between 1976 and 1994 were analyzed retrospectively. Four patients received bone marrow transplants (BMT) without prior myeloablative conditioning; transient osteoclast function was demonstrated in one of them. Sixty-five patients received myeloablative pretreatment. Recipients of a genotypically human leukocyte antigen (HLA)-identical BMT had an actuarial probability for 5-year survival, with osteoclast function, of 79%; recipients of a phenotypically HLA-identical bone marrow graft from a related or unrelated donor, or one HLA-mismatched graft from a related donor, had an actuarial probability for 5-year survival, with osteoclast function, of 38%; patients who received a graft from an HLA-haplotype mismatched related donor had a probability for 5-year survival of only 13%. The main problems in haplotype-nonidentical BMT were graft failure and BMT-related complications such as sepsis, bleeding, and interstitial pneumonia. Osteoclast function developed in all patients with full engraftment. Recovery of osteoclast function was associated with severe hypercalcemia in 24% of the patients with engraftment, especially those older than 2 years of age. At the time of BMT, severe visual impairment was present in 35% of the patients; of the 15 patients who had visual impairment at the time that a successful BMT was performed, two had improvement after BMT (13%). Within the total group, one patient had neurodegeneration. Engraftment of healthy donor cells had no influence on the progression of that abnormality and BMT thus had no beneficial effect on this phenotype of osteopetrosis. In general, however, early BMT remains the only curative treatment for autosomal recessive osteopetrosis.

Actuarial Analysis↗
PubMed1994

Mutation detection in the X-linked agammaglobulinemia gene, BTK, using single strand conformation polymorphism analysis.

The gene defective in X-linked agammaglobulinemia (XLA) has recently been isolated and identified as btk, a non-receptor protein tyrosine kinase. We have utilized the technique of single strand conformation polymorphism (SSCP) analysis for the btk gene to identify mutations in XLA patients. The btk gene in affected boys from 10 families was analysed and mutations were identified in eight cases; seven of these were point mutations and one was a small insertion. The mutations were found throughout the gene coding region. Six of the patients have classical XLA and two have less severe forms of the disease. We have also identified a polymorphism at nucleotide position 2031. This technique will allow us to provide more accurate diagnoses of the disease and to determine the nature of the functional defects in the btk gene in these families.

Agammaglobulinemia↗
PubMed1994

The effects of HIV-2 infection in a rural area of Guinea-Bissau.

OBJECTIVE: To investigate the clinical and immunologic effects, and pattern of mortality associated with HIV-2 infection. SETTING: A rural community in Guinea-Bissau. METHODS: Serologic screening of 2774 subjects aged > 14 years followed by studies of the prevalence of clinical and immunologic abnormalities among 133 subjects with HIV-2 infection and 160 seronegative controls, and surveillance of mortality among all subjects who were screened during a mean of 2 years of follow-up. RESULTS: Generalized lymphadenopathy was the only clinical abnormality significantly associated with HIV-2 infection. Infection was associated with lower CD4 counts and higher beta 2-microglobulin and neopterin levels. During follow-up, 5.5% of infected subjects died compared with 1.8% of the seronegatives (rate ratio adjusted for age and sex, 3.5; 95% confidence interval ((CI), 1.8-6.7). Proportional hazard regression analysis showed that the rate ratio varied with age (P = 0.003) and there was some evidence that the excess of mortality in infected subjects was, in absolute terms, least in the oldest subjects (trend test; P = 0.08). CONCLUSIONS: The findings support previous suggestions that HIV-2 is less pathogenic than HIV-1; the data also suggest that mortality associated with infection may be lower in older subjects.

Adolescent↗
PubMed1994

A clinical and immunological study of Netherton's syndrome.

Netherton's syndrome is a rare genodermatosis of unknown cause, which is classified as an ichthyosiform syndrome. A clinical and immunological study of seven patients with Netherton's syndrome illustrates the clinical spectrum of this disorder, the frequent association with atopy, and the absence of consistent immunological abnormalities. Failure to thrive in infancy was a feature in six of the seven patients, and was considered to be life-threatening in three. The skin disease evolved into ichthyosis linearis circumflexa in four of the seven, and the remaining three patients suffered from persistent or recurrent ichthyosiform erythroderma.

Adolescent↗
PubMed1994

Subpopulations of CD34-positive haemopoietic progenitors in fetal blood.

Flow cytometry was used to determine the percentage and number of circulating CD34+ cells in fetal blood from 100 pregnancies at 13-38 weeks gestation. When expressed as a percentage of the total number of lymphocytes, the proportion of CD34+ cells decreased exponentially from a mean of 11.1% (9.2 x 10(7)/l) at 13 weeks to 1.0% (3.0 x 10(7)/l) at 38 weeks (r = 0.751, P < 0.0001). The use of primitive fetal blood CD34+ progenitor cells for prenatal somatic gene therapy may have distinct advantages over postnatal somatic gene therapy.

Antigens, CD↗
PubMed1994

Early diagnosis of severe combined immunodeficiency syndrome.

Infants with severe combined immunodeficiency syndrome (SCIDS) have a greatly improved prognosis if diagnosed and treated before they develop overwhelming infection. Clinical and laboratory data on 45 patients with SCIDS were retrospectively reviewed to assess the value of absolute lymphocyte counts in making an early diagnosis. Ninety infants matched for age, sex, and presenting symptoms were used as controls. Thirteen (29%) infants with SCIDS were diagnosed at birth as previous siblings had been affected; 32 (71%) were diagnosed after the development of symptoms. Eighteen (56%) of these remained undiagnosed until after 6 months of age. The first symptoms occurred at a median of 5 weeks (range 1 day to 8 months) and the first admission to hospital was at 4 months (range 1 week to 16 months). Symptoms included respiratory infection (91%), vomiting and diarrhoea (81%), failure to thrive (88%), candidiasis (50%), and skin lesions (28%). The mean lymphocyte count was 1.71 x 10(9)/l compared with 7.2 x 10(9)/l in controls. Excluding one child with Omenn's syndrome (lymphocyte count 23.3 x 10(9)/l, all symptomatic infants with SCIDS had lymphocyte counts less than 2.8 x 10(9)/l at presentation. The median delay between the first abnormal lymphocyte count and diagnosis was seven weeks (range one day to 13 months). Twenty eight (88%) of 32 infants would have been diagnosed before 6 months of age if investigated after the first low lymphocyte count. These data indicate that low lymphocyte counts are predictive of SCIDS. Paediatricians are urged to pay attention to the absolute lymphocyte counts in all infants in whom a full blood count is performed. Those with lymphocyte counts persistently less than 2.8 x 10(9)l should be investigated for SCIDS.

Age of Onset↗
PubMed1994

Hypogammaglobulinaemia associated with normal or increased IgM (the hyper IgM syndrome): a case series review.

The clinical and immunological aspects of 16 children with the syndrome of hypogammaglobulinaemia associated with normal or increased IgM (the hyper IgM syndrome) and their responses to treatment are reviewed. Increased concentrations of IgM, neutropenia, and recurrent infections could usually be controlled by antimicrobial and intravenous immunoglobulin treatment. Together with the bacterial infections characteristic of hypogammaglobulinaemia, these patients often developed opportunistic infections, including Pneumocystis carinii pneumonia, often presenting in the first year of life. The occurrence of sclerosing cholangitis, neurological complications, and neutropenia may be a result of an underlying cell mediated immune deficiency, autoimmunity, or infection. Despite a high incidence of opportunistic infections, immunological investigations did not show any abnormality of T cell function. These findings are discussed in the light of the recent demonstration that the lack of expression of a T lymphocyte activation antigen is the molecular basis of the X linked form of the disorder.

Agammaglobulinemia↗