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Biomedical subjects

C Thomas

Publications and source records attributed to C Thomas.

At least 181 records · Page 10Linked to original sources
PubMed1998

Health problems in veterinary students after visiting a commercial swine farm.

In October 1993 and 1994, respectively, 77 and 76 third-year veterinary students visited a swine farm to work with pigs for 3 h. On both occasions, a large number of students reported flu-like symptoms after the visit. To further investigate this, the students were presented with a questionnaire modeled after the standard questionnaire used for evaluating organic dust exposure. General and/or respiratory symptoms were reported by 103/142 (72.5%) students. General symptoms, such as eye irritation, headache and tiredness were experienced by 60/103 (42.2%) students. Cough, nasal and throat irritation, and sinus trouble were the most prevalent respiratory symptoms and were reported by 94/103 (91%) of the students. Symptoms mostly developed the same day and disappeared within 3 d after exposure. The presence of respiratory and/or general symptoms was not significantly different between students who wore a mask during the lab or those who did not. Students with pre-existing allergies were more likely to develop respiratory symptoms than non-allergic students.

Adult↗
PubMed1998

MR of leptomeningeal spinal and posterior fossa amyloid.

We report an unusual cause of leptomeningeal MR enhancement, amyloid, along the surfaces of the spinal cord and brain stem and in the spinal subarachnoid space, with sacral intradural and epidural deposition. Type I familial amyloid polyneuropathy may cause amyloid deposition along the leptomeninges of the spinal cord and brain in addition to the visceral organs and the peripheral somatic and autonomic nerves.

Adult↗
PubMed1998

[Allogeneic bone marrow transplantation in congenital erythropoietic porphyria. Gunther's disease].

INTRODUCTION: The congenital erythropoietic porphyria (Günther's disease) (CEP) is a rare autosomal recessively metabolic disease due to the deficit of uroporphyrinogen III cosynthetase, fourth enzyme of the porphyrin-heme biosynthesis. This disease is characterized by severe cutaneous photosensitivity with profound skin lesions, hemolytic anemia and excess of uroporphyrin I excretion. The vital prognosis is very bad and until now, no treatment seems to be efficient. Bone marrow transplantation seems to be able to correct the enzymatic deficit that causes the disease because it is located in the bone marrow. OBSERVATION: We report the case of a four and a half year old girl who received an allogeneic bone marrow transplantation (BMT) at the age of two. Despite an encouraging result, the first transplantation failed. A second allogeneic transplantation was attempted eight months later with the same HLA identical heterozygous donor and bone marrow engrafment succeeded. Twenty one months after the second bone marrow transplantation, clinical and biological results are still excellent. DISCUSSION: No classical treatment of CEP really proved its efficiency and no one was curative. CEP resulting from an homozygous deficiency in uroporphyrinogen III cosynthetase, enzyme that takes part in the porphyrin-heme biosynthesis which is principally located in the erythropoietic system of the bone marrow, substitution of this defective lineage by BMT was a very attractive treatment to correct this anomaly. The first bone marrow transplantation attempted on an affected child in 1990 in Manchester failed because the patient died of infections complications. After the failure of the first transplantation, our little patient is now healed twenty one months after the second BMT and biochemical anomalies are corrected. If a long follow up is necessary to appreciate the long-term efficiency of this treatment, allogenic bone marrow transplantation seems to cure Günther's disease and must be proposed as the treatment of this affection.

Bone Marrow Transplantation↗
PubMed1997

Chromosomal localization, gene structure and transcription pattern of the ORFX gene, a homologue of the MHC-linked RING3 gene.

We have mapped the human ORFX gene to chromosome 9q34 and determined its complete gene structure. Comparison with RING3, the human MHC-linked homologue on 6p21.3, shows the two gene structures to be highly conserved but with an approximate threefold expansion in the ORFX introns. RING3 and ORFX are found to be ubiquitously expressed in human adult and foetal tissues. Evidence suggests that the two genes may have arisen from an ancient duplication in a common ancestral chromosome.

Adult↗
PubMed1997

Left lateralized P300 amplitude deficit in schizophrenic patients depends on pitch disparity.

The general reduction of P300 amplitude in response to auditory oddball stimuli is one of the most consistently replicated biological observations in schizophrenic patients. Several groups have reported a P300 asymmetry in schizophrenic patients, others have not been able to replicate this finding. In order to clarify this issue, we examined the effect of stimulus discriminability on P300 amplitude distribution in schizophrenic patients and in age-matched normal control subjects, using two different auditory oddball paradigms. The detection of the target tone was either simple or difficult, due to manipulation of pitch disparity. The P300 amplitude was comparatively smaller in the schizophrenic patient group compared to the healthy controls and in the difficult task compared to the simple. The schizophrenic patients showed a specific P300 amplitude reduction over left temporal electrode sites when the simple paradigm was used. The difficult paradigm did not elicit asymmetrical P300 amplitudes in schizophrenic patients.

Adult↗
PubMed1997

Lack of expression of E-cadherin is associated with dissemination of Langerhans' cell histiocytosis and poor outcome.

Langerhans' cell histiocytosis (LCH) often occurs in children as a cutaneous disease. The course of the disease is characterized by either spontaneous resolution or multivisceral dissemination with poor prognosis. The pathogenesis of LCH is not known. Since E-cadherin mediates homophilic adhesion of normal Langerhans' cells to keratinocytes and is also a ligand of the alpha E beta 7 intraepithelial lymphocyte integrin, this study was undertaken to investigate whether its expression on LCH cells correlates with the clinical behaviour of the disease. Clinical records of 14 children with LCH, all of whom had cutaneous involvement, were retrospectively analysed. The expression of E-cadherin was studied by in situ immunohistochemistry on 22 frozen biopsy samples with two specific monoclonal antibodies. LCH cells of the seven children with only skin involvement were positive for E-cadherin. By contrast, LCH cells of the seven children who further developed extensive LCH disclosed a negative or low expression of E-cadherin. This study shows that dissemination and poor prognosis are associated with lack of E-cadherin expression on LCH cells. Aggressive clinical evolution of LCH may therefore be related to the loss of functions mediated by E-cadherin.

Biomarkers↗
PubMed1997

Clinical spectrum of X-linked hyper-IgM syndrome.

We report the clinical and immunologic features and outcome in 56 patients with X-linked hyper-IgM syndrome, a disorder caused by mutations in the CD40 ligand gene. Upper and lower respiratory tract infections (the latter frequently caused by Pneumocystis carinii), chronic diarrhea, and liver involvement (both often associated with Cryptosporidium infection) were common. Many patients had chronic neutropenia associated with oral and rectal ulcers. The marked prevalence of infections caused by intracellular pathogens suggests some degree of impairment of cell-mediated immunity. Although lymphocyte counts and in vitro proliferation to mitogens were normal, a defective in vitro proliferative response to antigens was observed in some patients, and additional defects of cell-mediated immunity may be presumed on the basis of current knowledge of CD40-ligand function. All patients received regular infusions of immunoglobulins. Four patients underwent liver transplantation because of sclerosing cholangitis, which relapsed in there. Three patients underwent bone marrow transplantation. Thirteen patients (23%) died of infection and/or liver disease. X-linked hyper-IgM syndrome, once considered a clinical variant of hypogammaglobulinemia, is a severe immunodeficiency with significant cellular involvement and a high mortality rate.

Bone Marrow Transplantation↗
PubMed1997

Occurrence of myeloproliferative disorder in patients with Noonan syndrome.

We report four cases of Noonan syndrome associated with chronic myelomonocytic leukemia in childhood. These children shared some hematologic features: thrombocytopenia, splenomegaly in the first months of life, occurrence of chronic myelomonocytic leukemia without abnormalities of the initial bone marrow karyotype, and, in three cases, improvement of the hematologic disease. A common pathophysiologic process in such patients is suggested.

Bone Marrow↗
PubMed1997

Potassium-magnesium citrate is an effective prophylaxis against recurrent calcium oxalate nephrolithiasis.

PURPOSE: We examined the efficacy of potassium-magnesium citrate in preventing recurrent calcium oxalate kidney calculi. MATERIALS AND METHODS: We conducted a prospective double-blind study of 64 patients who were randomly assigned to receive placebo or potassium-magnesium citrate (42 mEq. potassium, 21 mEq. magnesium, and 63 mEq. citrate) daily for up to 3 years. RESULTS. New calculi formed in 63.6% of subjects receiving placebo and in 12.9% of subjects receiving potassium-magnesium citrate. When compared with placebo, the relative risk of treatment failure for potassium-magnesium citrate was 0.16 (95% confidence interval 0.05 to 0.46). Potassium-magnesium citrate had a statistically significant effect (relative risk 0.10, 95% confidence interval 0.03 to 0.36) even after adjustment for possible confounders, including age, pretreatment calculous event rate and urinary biochemical abnormalities. CONCLUSIONS: Potassium-magnesium citrate effectively prevents recurrent calcium oxalate stones, and this treatment given for up to 3 years reduces risk of recurrence by 85%.

Adult↗
PubMed1997

Having a baby: some disabled women's reproductive experiences.

OBJECTIVE: To explore some of the social barriers disabled women face when they think about having a child, become pregnant, come into contact with the maternity and related services, and become mothers. DESIGN: A qualitative study involving in-depth semi-structured interviews with 17 disabled women. This was a follow-up study associated with a large health authority commissioned survey on the 'maternity preferences' of women of childbearing age resident in one city. SETTING: One city in the north of England. Fifteen of the women were interviewed in their own homes and two were interviewed in their workplaces. PARTICIPANTS: The women who were interviewed had a wide range of impairments, and were at different stages in their reproductive journeys. FINDINGS: We report on three important themes which emerged through the analysis of the interview transcripts: issues of poor 'access' within the maternity services; inadequately met information needs; and the experience of receiving inadequate or inappropriate 'help' from health professionals and social care workers. KEY CONCLUSIONS: The study provides support for the claims made in Changing Childbirth (Department of Health 1993) that professional practice and other features of maternity services can place barriers in the paths of disabled women. IMPLICATIONS FOR PRACTICE: Midwives should respect the right of disabled women to be self-determining, for example, by first asking disabled women what their needs are and how assistance, if desired, can best be given.

Adaptation, Psychological↗
PubMed1997

Hypochlorous acid disrupts the adhesive properties of subendothelial matrix.

We have investigated whether the cell adhesion-promoting properties of the subendothelial matrix are affected by exposure to neutrophil-derived oxidants. Native subendothelial matrix was exposed to increasing doses of H2O2 in the presence of myeloperoxidase and Cl- or to reagent hypochlorous acid (HOCl). Increasing doses of either oxidant system resulted in progressive loss in the adhesive properties of the matrix, and phase contrast microscopy showed that the cells failed to attach to and spread on the oxidant-treated surface. When cells were replated on the treated matrix in the presence of 20% serum, they did attach, but showed abnormal spreading and morphology in longer-term culture. In a modified ELISA system, binding of antibodies specific to fibronectin, thrombospondin and laminin was also disrupted by prior exposure of the matrix to HOCl. Of these components, the cell-binding region of fibronectin was most affected by HOCl, thrombospondin and laminin were less sensitive, and the collagen-binding region of fibronectin was the most resistant. SDS-PAGE of 35S-labelled subendothelial matrix proteins indicated that there was no major irreversible crosslink formation or fragmentation after exposure to HOCl or the myeloperoxidase system, although formation of disulfides is quite likely.

Cell Adhesion↗
PubMed1997

Language processing in aphasia: changes in lateralization patterns during recovery reflect cerebral plasticity in adults.

During single word processing the negative cortical DC-potential reveals a left frontal preponderance in normal right-handers as well as in patients with a history of transient aphasia. Lateralization of DC-negativity therefore provides a reliable and robust method for the assessment of language dominance. In 11 stroke patients with permanent aphasia this physiological pattern changed to bilateral activation reflecting an additional right-hemispheric involvement in compensatory mechanisms in aphasia. Along with complete clinical recovery the classical aphasic syndromes revealed specific differences in changes of their lateralization patterns. In Broca's aphasia the initial right-hemispheric preponderance changed to a left frontal lateralization while in Wernicke's aphasia a presumably permanent shift towards the right hemisphere occurred. Differences in lateralization patterns might reflect different mechanisms of recovery such as the initial disinhibition of homologous areas contralaterally and subsequent collateral sprouting and synaptic modulation. The assessment of changes in lateralization of the cortical DC-potential during language tasks in a non-invasive, safe method with excellent time resolution that might provide further insights in the neural basis of recovery from aphasia.

Action Potentials↗
PubMed1997

Histological evidence of fetal pig neural cell survival after transplantation into a patient with Parkinson's disease.

The movement disorder in Parkinson's disease results from the selective degeneration of a small group of dopaminergic neurons in the substantia nigra pars compacta region of the brain. A number of exploratory studies using human fetal tissue allografts have suggested that transplantation of dopaminergic neurons may become an effective treatment for patients with Parkinson's disease and the difficulty in obtaining human fetal tissue has generated interest in finding corresponding non-human donor cells. Here we report a post-mortem histological analysis of fetal pig neural cells that were placed unilaterally into the caudate-putamen brain region of a patient suffering from Parkinson's disease. Long-term (over seven months) graft survival was found and the presence of pig dopaminergic neurons and other pig neural and glial cells is documented. Pig neurons extended axons from the graft sites into the host brain. Furthermore, other graft derived cells were observed several millimeters from the implantation sites. Markers for human microglia and T-cells showed only low reactivity in direct proximity to the grafts. This is the first documentation of neural xenograft survival in the human brain and of appropriate growth of non-human dopaminergic neurons for a potential therapeutic response in Parkinson's disease.

Aged↗
PubMed1997

Immunohistochemical processing of tissue which allows for embedding in Araldite, and orientation and correlation between light and electron microscopic staining.

This paper describes a simple and efficient method for the immunohistochemical processing of tissue sections on glass slides and the subsequent transfer of the entire section to an Araldite medium. These sections present in one plane can then be orientated and when cut provide the user with whole tissue, free from gaps due to folding. This procedure therefore enables the changes in protein concentration and distribution to be assessed and correlated within and between different cells at the light and electron microscopic level. This procedure may be of use in other microscopic techniques studies.

Animals↗