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Biomedical subjects

M Weber

Publications and source records attributed to M Weber.

At least 289 records · Page 16Linked to original sources
PubMed1998

Corticomotorneuronal hyper-excitability in amyotrophic lateral sclerosis.

We have analysed how the behaviour of a voluntarily activated motor unit changes when subjected to 100-150 threshold cortical stimuli using peristimulus time histograms (PSTHs). This is a measure of the integrity of the corticomotoneuronal core innervating a single anterior horn cell. One hundred and thirty units in 29 patients with ALS and 35 units in eight age-matched normal controls were studied. PSTHs were constructed using 1-ms bins of stimulus triggered sweeps with a total analysis time of 250 ms (50 ms before and 200 ms after the stimulus). In ALS the primary peak of the PSTH was delayed in onset and prolonged in duration. The primary peak was further analysed by finer 0.2-ms bins, which showed in ALS there were more sub-components than normally occur. Additional sub-components in the PSTH primary peak implies a hyper-excitable corticomotoneuron that fires excessively. Excitability could be glutamate induced and/or due to failure of GABA inhibitory mechanisms. Some glutamate antagonsits may be therapeutic in ALS because of their anticonvulsant or GABergic properties rather than their anti-glutamate properties. GABA(B) agonists might have a role in future therapeutic combined therapies for ALS.

Adult↗
PubMed1998

Laparoscopic nephrectomy: the experience of the laparoscopy working group of the German Urologic Association.

PURPOSE: The centers of the laparoscopy working group of the German Urologic Association collected data to prove the efficacy, safety and reproducibility of laparoscopic nephrectomy. MATERIALS AND METHODS: At 14 centers 482 laparoscopic nephrectomies have been performed until December 1996 via a transperitoneal approach in 344 (71%) and a retroperitoneal approach in 138 (29%). All 482 laparoscopic nephrectomies were performed by a total of 20 surgeons with an average of 24 procedures per surgeon (range 4 to 105). The indications for nephrectomy were benign renal pathology in 444 patients (92%), including renovascular disease in 28%, hydronephrosis in 20%, reflux nephropathy in 15%, chronic pyelonephritis in 12%, end stage nephrolithiasis in 11%, renal dysplasia in 4% and renal tuberculosis in 1%. Of the remaining 38 patients (8%) laparoscopic radical nephrectomy was performed for renal cell carcinoma in 5% and for upper tract transitional cell carcinoma in 3%. RESULTS: Operating time depended mainly on the pathology of the kidney (that is small dysplastic organ versus large hydronephrosis) and the learning curve of the surgeon. However, the average operating time did not vary significantly among the different centers (maximum 277.6 and minimum 81.9 minutes). Intraoperative or perioperative complications were noted in 29 patients (6.0%), including bleeding in 22 (4.6%), bowel injury in 3, hypercarbia in 2 and pleura lesion in 1 and pulmonary embolism in 1. The conversion rate was 10.3% (bleeding, bowel injury, difficult dissection), including 4 patients with renal tuberculosis, 2 with xanthogranulomatous nephritis, and 1 each following renal trauma and embolization. The re-intervention rate was 3.4% due to bleeding in 6 cases, abscess formation in 3, intestinal stenosis in 2 and a pancreatic fistula and port hernia in 1. Mean hospital stay was 5.4 days. CONCLUSIONS: Laparoscopic nephrectomy has become a well established procedure in those urology departments focusing on laparoscopy. The indications and results are reproducible at these centers. However, for patients with severe perinephritis (that is renal tuberculosis, xanthogranulomatous nephritis, posttraumatic atrophy) a higher likelihood of open conversion must be considered.

Adolescent↗
PubMed1998

Superior biologic activity of the recombinant bee venom allergen hyaluronidase expressed in baculovirus-infected insect cells as compared with Escherichia coli.

BACKGROUND: Hyaluronidase (Hya) is one of several allergens in honeybee venom. Its cDNA sequence was recently described. OBJECTIVE: We sought to express recombinant Hya in prokaryotic and eukaryotic systems and to compare it with natural (n)Hya for biologic activity. METHODS: In Escherichia coli Hya was produced as inclusion body 6 x His-fusion protein. In baculovirus-infected insect cells expression was obtained by cotransfection of linearized Bac-N-Blue DNA and pMelBac transfer vector into Spodoptera frugiperda cells. RESULTS: Enzymatic activity of Hya from the baculovirus system was equal to nHya, and that of the enzyme expressed in E. coli was only 20% to 30% of nHya. In vitro IgE binding was similar in nHya and the enzyme from baculovirus but markedly lower in Hya expressed in E. coli. CONCLUSIONS: Biologic activity of Hya expressed in baculovirus-infected insect cells was comparable with that of the natural enzyme, indicating a native-like conformation of the recombinant protein. In contrast, the enzyme expressed in E. coli as an inclusion-body protein and reconstituted in vitro reached only 20% to 30% of the activity of nHya.

Allergens↗
PubMed1998

Organ transplantation in the twenty-first century.

Major advances in the understanding of the immunologic process responsible for organ or cellular transplant rejection, a dramatic improvement in available immunosuppressive drugs, development of more sophisticated surgical techniques, and important progress in posttransplant intensive care over the last 30 years have led to a remarkable improvement in success following organ transplantation. Whereas excellent short-term survival of most transplanted organs is readily achieved, graft loss because of chronic rejection and the worsening problem of organ donor shortage remain major concerns in the field of transplantation. Recent advances in immunosuppressive drugs, induction of immunologic tolerance, and gene therapy strategies may help to prolong organ allograft survival in the future. Revised criteria for organ donation and xenotransplantation may one day solve the problem of organ supply. Today, as we approach the next millennium, we are optimistic that the elusive goal of immunologic tolerance will be achieved and perhaps applied to animal tissue. Such will certainly be the challenge for the next century.

Forecasting↗
PubMed1998

[Ischemic stroke in young patients and/or livedo: is it important to look for anti-beta 2-glycoprotein I antibodies?].

PURPOSE: This study was aimed at determining the prevalence of anti-beta 2glycoprotéine I antibodies (anti-beta 2-GPI antibodies) in young adult patients presenting with either livedo reticularis or ischemic stroke. METHODS: Forty patients referred between February 1996 and February 1997 underwent clinical examination and laboratory tests with search for anticardiolipin antibodies (ACL antibodies), lupus anticoagulant (LA) and anti-beta 2GPI antibodies. RESULTS: Twenty-one patients presented with ischemic stroke (one with ACL antibodies), 13 had livedo (six with ACL antibodies, two with LA) and six patients presented with Sneddon's syndrome (two with ACL antibodies, two with LA). Only one was positive for anti-beta 2-GPI antibodies. CONCLUSION: beta 2-GPI is a cofactor that increases anticardiolipin antibody adhesion to cardiolipin. Our results suggest that the prevalence of anti-beta 2GPI antibodies is not high in young patients with either livedo reticularis or ischemic stroke. However, due to the small number of patients included in the study, definite conclusions may not be drawn out. Anti-beta 2-GPI antibodies assay is not justified in routine evaluation of patients with either livedo reticularis or ischemic stroke.

Adult↗
PubMed1998

[Respiratory evolution of patient with mucoviscidosis treated with mucolytic agents plus dornase alfa].

AIM: Modifications of bronchial secretions in cystic fibrosis patients account for the long-lasting use of mucolytic agents, despite the lack of adequately controlled clinical studies supporting this approach. Hyperviscosity of bronchial secretions mainly depend on their high DNA content, as a result of degradation of polymorphonuclear neutrophils mobilized by infection and inflammation. This phenomenon has led to the treatment of respiratory complications with human recombinant deoxyribonuclease (dornase alfa). In the present study, we compared the clinical and respiratory outcome in patients receiving mucolytic agents followed by dornase alfa, each for 1 year. POPULATION AND METHODS: Fifty-four patients, aged 5 years or more, have been prospectively followed for 2 years. They received first a 12-month association of mesna (two nebulisations per day) and oral ambroxol (60 mg per day, divided in two doses), followed by a 12-month treatment with one daily aerosol of dornase alfa only (2.5 mg per day). The primary end-points were the results of pulmonary function tests. Secondary end-points were subjective symptoms, bacterial colonization, consumption of antibiotics, and clinical tolerance. RESULTS: At the end of the 12-month mucolytic therapy, a significant decrease of forced expiratory volume/second (FEV1, -10.5% as compared to baseline values) and forced vital capacity (FVC, -12.8%) was observed. At the end of 12-month dornase alfa, FEV1 and FVC had increased by 7.7 and 5.3%, respectively. This change was statistically significant only for FEV1 in most severely disabled patients. However, forced expiratory flow 25-75% (FEF 25-75) decreased during the 2 year period of observation, by 5.6% the first year and 4.9% the second year. The mean number of days with parenteral antibiotics did not statistically differ between both treatments, except for patients more than 15 years of age. In this subgroup, the mean number decreased from 40 days in the first year to 27 in the second year (P < 0.05). Acceptability of treatment by the patients themselves was better with dornase alfa than with mucolytic therapy. However, several episodes of hemoptysis, frequent in only one case, were associated with the treatment by dornase alfa. CONCLUSION: Dornase alfa was associated with a stabilisation, and even a trend to improvement in pulmonary function tests. This stabilisation is by itself a very encouraging result. Long-term comparative studies are needed to evaluate the benefits of dornase alfa in the treatment of respiratory complications of cystic fibrosis and specify the optimal modalities of its use. Synergistic combinations with mucolytic therapy and/or anti-inflammatory drugs could be viewed as a future prospect.

Adolescent↗
PubMed1998

Nutritional status of children admitted to hospital with different diseases and its relationship to outcome in The Gambia, West Africa.

Admission records from two paediatric units in The Gambia were used to explore the relationship between admission weight and different diseases. In total 13579 hospitalized children were analysed. For comparison, 7399 children were recruited from several surveys of well subjects to provide anthropometric values for healthy Gambian children. Compared to the control children, mean admission weights were lower for malaria (weight for age z-score: -1.602), cerebral malaria (-1.547), transfused malarial anaemia (-1.764), pneumonia (-1.725), meningitis (-1.362), gastro-enteritis (-2.497) and malnutrition (-3.786). Children with bronchiolitis did not have a significantly different weight for age than the controls. Outcome of the hospital admission was recorded and related to the weight on admission. In all disease categories the death rate rose with decreasing admission weight with the exception of bronchiolitis. For all diseases taken together, case fatality was 7.2% for children with a weight for age z-score above -2 Standard Deviations (SD), 9.3% between -2 and -3 SD, 15.6% between -3 and -4 SD and 22.7% for children with weight for age SD z-scores less than -4. Malnourished children are more susceptible to several infectious diseases frequently seen in developing countries and nutritional interventions, as well as standard treatment, may improve outcome.

Body Weight↗
PubMed1998

Meningitis caused by a serogroup W135 clone of the ET-37 complex of Neisseria meningitidis in West Africa.

Meningococci belonging to serogroup W135 caused several cases of meningococcal meningitis in The Gambia in 1995 and were isolated during a serogroup A epidemic in Mali in 1994. The eight isolates tested belonged to the same clone of the ET-37 complex and differed in several bands from the pulsed-field gel electrophoresis restriction pattern of serogroup C meningococci of the ET-37 complex isolated in Mali. Three of 6 patients infected in The Gambia died, indicating that this W135 clone is virulent. Vaccines that protect only against infections with meningococci belonging to serogroups A and C are usually used to control outbreaks in Africa, although vaccines containing the W135 polysaccharide are available. The findings of this study indicate that outbreaks of meningococcal meningitis in Africa can be associated with serogroup W135 infections and that serogrouping is essential before vaccination campaigns are started.

Adolescent↗
PubMed1998

Changes of cerebral perfusion after osmotherapy in acute cerebral edema assessed with perfusion weighted MRI.

Perfusion is thought to be impaired in brain edema due to reduced perfusion pressure. Brain edema therapy is assumed to improve perfusion. We assessed regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and mean transit time of blood (MTT) using perfusion-weighted magnetic resonance imaging (MRI) in 15 patients showing acute local brain edema due to infarction or intracerebral hematoma. Patients were treated by intravenous infusion of 125 ml 40% sorbitol over 10 min. rCBF, rCBV and MTT in the edematous region were measured before and 30 min after treatment. Before treatment rCBF (46.5 +/- 12.1 vs. 42.9 +/- 10.5 ml 100 g-1 min-1), MTT (4.7 +/- 1.9 vs. 4.0 +/- 1.7 s) and rCBV (5.4 +/- 1.7 vs. 4.7 +/- 1.1 ml 100 g-1) were significantly (p < 0.05) increased in the edematous region compared to the contralateral side. After treatment no significant differences could be found. We interpret the elevation of MTT and rCBV in the edema as signs of an autoregulative compensation of an impaired perfusion. rCBF is even over-compensated. After brain edema therapy perfusion seems normalised. This new MRI method appears as useful for measuring therapeutic effects on cerebral perfusion.

Aged↗
PubMed1998

Bacteraemia in cerebral malaria.

As part of a treatment trial of cerebral malaria, blood cultures were done in 276 Gambian children, aged between 1 and 9 years, with cerebral malaria. Fourteen (5%) of these were positive. The organisms isolated were Staphylococcus aureus (6), coliforms (4), Pseudomonas spp. (2), Salmonella spp. (1) and Streptococcus spp. (1). Thirteen of these children survived, most without appropriate antibiotic treatment. Most of the retrieved organisms were therefore suspected to be contaminants. Bacteraemia complicating cerebral malaria is not common in The Gambia, and routine antibiotic treatment of children with cerebral malaria is not warranted.

Bacteremia↗
PubMed1998

A novel method for controlling the quantity of mitomycin-C applied during filtering surgery for glaucoma.

The use of a sponge impregnated with mitomycin-C is an increasingly common practice in glaucoma surgery. The appropriate antibiotic concentration and exposure time have been considered in the literature, but not the exact amount to be used or the size of the sponge. The purpose of this study was to estimate the quantity of mitomycin-C contained in sponges prepared by different surgeons as compared to that in applicators of the type used in Schirmer's test graduation (5 x 5 mm). Four surgeons each cut and prepared 10 sponges for intraoperative use according to their usual method. The same procedure was performed with 10 Schirmer's test graduations. Each sponge and each graduation was immersed in a solution of mitomycin-C 0.2 mg/ml, and the quantity of antibiotic (microg) in each was calculated as the difference between wet and dry weight. The mean quantity (+/- SEM) of mitomycin-C contained in cut sponges was 9.6 +/- 4.4 microg (range 1.9-17.3), and the differences between surgeons were statistically significant (p<0.0001). The mean quantity of antibiotic in Schirmer's test graduation was 1.7 +/- 0.3 microg (range 1.1-2.5), and the differences between surgeons were not statistically significant (p=0.79). The quantities of mitomycin-C contained in sponges prepared for glaucoma surgery differed for a given surgeon and between surgeons. Thus, variations in the doses applied to the sclera could account for certain complications due to mitomycin-C. The use of a Schirmer's test graduation improves predictability for the quantity of mitomycin-C applied to the sclera.

Antibiotics, Antineoplastic↗
PubMed1998

Epidemiology of invasive pneumococcal disease in the Western Region, The Gambia.

BACKGROUND: Streptococcus pneumoniae is a major cause of morbidity and mortality in young children in the developing world. The recent development of pneumococcal polysaccharide/protein conjugate vaccines may make possible prevention of this infection. However, little is known about the epidemiology of invasive pneumococcal disease in children in the developing world. OBJECTIVES: To determine the incidence and epidemiologic features of invasive pneumococcal disease in children resident in a semiurban area of The Gambia. METHOD: The study was part of a large trial of an Haemophilus influenzae type b vaccine that recruited 42 848 children at the age of 2 months during the period March, 1993, to October, 1995. Follow-up of study children continued until December 31, 1995; therefore the first children to enter the trial were followed for 2.5 years and the last for just a few months. During the period of surveillance, 2256 children were investigated for possible invasive pneumococcal disease when they presented to a hospital or health center. RESULTS: We detected 110 cases of pneumococcal disease. Pneumonia was the most common form of invasive pneumococcal disease observed (75.5% of patients). The incidence of pneumococcal disease was 224 [95% confidence interval (CI) 171, 277] per 100,000 child years among children ages 2 to 11 months, 139 (95% CI 93, 184) per 100,000 among children ages 12 to 23 months and 82 (95% CI 21, 143) per 100,000 among children ages 24 to 35 months. Pneumococci of serogroups 14, 6, 5, 23, 19, 46 and 2 were isolated most frequently. Susceptibility to pneumococcal disease was not increased significantly among Haemophilus influenzae type b-vaccinated children. CONCLUSIONS: The pneumococcus is a major cause of bacterial infection in The Gambia. A proposed nine-valent pneumococcal conjugate vaccine for developing countries containing conjugates of serogroups 1, 4, 5, 6, 9, 14, 18, 19 and 23 would cover 74% of cases of invasive pneumococcal disease in children resident in the Western Region of The Gambia.

Bacterial Capsules↗
PubMed1998

A polymerase chain reaction for the diagnosis of Haemophilus influenzae type b disease in children and its evaluation during a vaccine trial.

BACKGROUND: Determination of the etiology of pneumonia in young children is difficult because blood culture, the usual method of diagnosis, is positive in only a small proportion of cases. For this reason vaccine trials that include bacterial pneumonia as an endpoint must be large. OBJECTIVES: To determine whether a diagnostic test based on a polymerase chain reaction could be used as an alternative to conventional blood culture for diagnosis of invasive Haemophilus influenzae type b (Hib) infections in young children investigated during the course of a large vaccine trial. METHODS: DNA was extracted from blood culture supernatants and probed for the presence of Hib DNA with a PCR assay with primers derived from the cap gene locus of Hib. Results of the PCR assay were compared with those obtained by conventional culture techniques. RESULTS: Blood cultures were obtained from 1544 children with suspected pneumonia, meningitis or septicemia and from 31 healthy control children who were contacts of cases. Blood culture supernatants were tested for Hib DNA in the PCR test. The sensitivity and specificity of a positive PCR test in blood culture supernatant as against culture of Hib from any normally sterile site were 100 and 99%, respectively. Eleven children had positive Hib PCR tests on blood culture supernatants but were negative by culture. In one of these cases Hib was isolated from a lung aspirate and in two other patients H. influenzae strains other than Hib were obtained from the cerebrospinal fluid. Eight of these 11 children were in the control group. When the results of the PCR assay were used to determine vaccine efficacy, a value of 86% was obtained compared with a figure of 95% obtained when conventional culture techniques were used. CONCLUSIONS: An Hib PCR assay on blood culture supernatants proved to be sensitive and specific for the diagnosis of Hib disease in children. The distribution of PCR-positive, culture-negative cases between Hib-vaccinated and control groups paralleled that of culture-positive cases, suggesting that most of these children had been infected with Hib. A trial of a highly efficacious vaccine provides a novel way for evaluating new diagnostic tests for which there is no standard diagnostic test of 100% reliability.

Bacteremia↗
PubMed1998

Thanatophoric dysplasia type II: new entity?

There is some question about whether the two forms of thanatophoric dysplasia (TD), Type II with and Type I without cloverleaf skull, belong to the same entity. Thus, we investigated one 6-day-old TD with cloverleaf skull using examination of the external phenotype, radiology, autopsy, skeleton preparation, large section histology, detailed section histology, and ultrastructure. The loss of the three-phase contours-characteristics for Type I (54)--in certain metaphyses, the absence of the perichondral spurs to some extent, and their substitution by a structure similar to the perichondral "ring of Lacroix" have a suggested origin in normal cartilage-bone tissue. The same mechanism is postulated (a) for the appearance of less bent or normally shaped tubular bones compared with TD Type I, and their corresponding increased mechanical stability, and (b) for the less amount of platyspondyly in Type II than in Type I. We suggest that the malformation of the cloverleaf skull has its origin in the promontory growth of the relatively normal cartilage-bone tissues at the skull base resulting in an early synostosis and a consecutive fusion of the cranial sutures. The ultrastructural analysis of chondrocytes demonstrates the significant contribution of electron microscopy for TD studies. We suggest that pathologically altered light chondrocytes accounts for plump cross-striated collagen fibrils, the reduced cellular proliferation, and the impaired formation of columnar and hypertrophic zones. It is clear that normal cartilage-bone tissue distributed among "thanatophoric" tissue is the reason for the differences between Type I and Type II. Hypotheses are presented that explain this tissue mosaicism. Thus, TD Type I and TD Type II do not represent two different entities but the same entity with varying features due to mutational events occurring at different times.

Bone and Bones↗
PubMed1998

The different appearance of the oculodentodigital dysplasia syndrome.

We report on two families with the oculodentodigital (ODD) dysplasia syndrome, also called Meyer-Schwickerath syndrome. It represents a rare disorder characterized by eye and facial abnormalities causing a unique facial appearance. The phenotype of the young patients resembles those of identical twins. We found syndactyly mostly at the hands and, additionally, characteristic phalangeal aberrations, defects in teeth enamel, and trichosis. In the one family, the ODD dysplasia syndrome seemingly originated in a new mutation. The affected child was treated surgically in our clinic (syndactyly separation). In the other family, three patients (grandmother, mother, and granddaughter) were subjects of syndactyly separation. The aim of our surgeries was to separate the webbed fingers so there would be a normal spread and to improve the function and appearance of fingers. The ODD dysplasia syndrome correlates with the Hallermann-Streiff syndrome, or oculomandibulodyscephaly, which is characterized by a typical skull shape (brachicephaly with frontal brossing), a bird-like face, and eye abnormalities (congenital cataracts and microphthalmia).

Abnormalities, Multiple↗