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Biomedical subjects

J N Thompson

Publications and source records attributed to J N Thompson.

At least 19 recordsLinked to original sources
PubMed1992

N-acetylglucosamine 6-sulphatase deficiency in a Nubian goat: a model of Sanfilippo syndrome type D (mucopolysaccharidosis IIID).

A male Nubian goat (SD-1) presented at birth with neurological manifestations consistent with a lysosomal storage disease. Histological studies of tissue obtained at autopsy suggested glycosaminoglycan storage. Total urinary glycosaminoglycan levels, as measured by the uronic acid method, were elevated but overlapped with levels in a younger control goat. However, N-sulphate content was increased 2- to 5-fold, suggestive of heparan sulphate excretion, and this elevation was confirmed by cellulose acetate electrophoresis. Further, urinary levels of free N-acetylglucosamine 6-sulphate were increased 6-fold over controls, SD-1 cultured skin fibroblasts, labelled with [35S]sulphate from the incorporated twice as much radioactivity into macromolecular material as did normal fibroblasts. Forty-eight hours after removal of [35S]sulphate from the medium the SD-1 fibroblasts retained 58% of the label, whereas in control fibroblasts it had declined to 20%, indicative of [35S]proteoglycan storage in SD-1. The assay of fibroblast extracts revealed a profound deficiency of N-acetylglucosamine 6-sulphatase whereas eight other activities including beta-mannosidase, arylsulphatase B, iduronate 2-sulphatase, N-acetylgalactosamine 6-sulphatase, and heparin sulphamidase were normal. Mixing of SD-1 sonicates with normal sonicates showed no evidence of an inhibitor, and mixing of SD-1 sonicates with Sanfilippo D cell sonicates yielded no activity. These data ruled out multiple sulphatase deficiency and suggested the first example of the human Sanfilippo syndrome, type D (N-acetylglucosamine 6-sulphatase deficiency) in goats.

Acetylglucosamine↗
PubMed1992

Attempted enzyme replacement using human amnion membrane implantations in mucopolysaccharidoses.

Amnion membrane implantation has been proposed as an approach to enzyme replacement in mucopolysaccharidoses. Human amnion membranes have been subcutaneously implanted in the abdominal wall in 19 patients with mucopolysaccharidoses (MPS I, II and III). A protocol was developed for the objective evaluation of experimental treatments of these patients. Systematic evaluation of the clinical status before and 6 months after amnion membrane implantation reveals no change in function except improvement in joint mobility. The sum of all joint movements showed improvement from baseline values to 6 months after implantation by ANOVA followed by post-hoc analysis (p less than 0.056). The only specific joint movements to significantly improve after 6 months were shoulder extension (p less than 0.01) and hip internal rotation (p less than 0.05). Serial measurements of the deficient lysosomal enzyme activity in serum and white blood cells did not increase in any patient after amnion membrane implantation. Urinary glycosaminoglycan excretion decreased transiently in 2 of 10 patients after implantation, but a second amnion membrane implantation did not result in any change. Biopsy of the implantation site in 10 patients 6 months after amnion membrane implantation revealed a foreign-body reaction with giant cell formation and fibrosis and no recognizable amnion membrane tissue. We conclude that human amnion membrane implantation is not an effective therapy in mucopolysaccharidoses.

Abdominal Muscles↗
PubMed1992

The selective use of fine catheter peritoneal cytology and laparoscopy reduces the unnecessary appendicectomy rate.

The effect of a management protocol incorporating the selective use of fine catheter peritoneal cytology (FCPC) and laparoscopy on the unnecessary appendicectomy rate was studied in adult patients (> or = 16 years) treated at one district general hospital over an 11-month period. Appendicectomy was performed on 62 adult patients managed according to this protocol, six (10%) of whom had a histologically normal appendix and no other acute condition requiring surgery. A further 57 patients underwent appendicectomy after standard clinical assessment and investigation without the use of FCPC or laparoscopy. Nineteen (33%) of these patients had a histologically normal appendix removed, with no other acute condition requiring surgical treatment. The selective use of FCPC and laparoscopy significantly reduced the unnecessary appendicectomy rate from 33% to 10% (chi 2 = 10.0, P < 0.005). The more widespread use of these techniques in patients with suspected appendicitis is therefore recommended.

Abdomen, Acute↗
PubMed1992

Laboratory diagnosis of genetic disorders.

Many genetic disorders affect vision or result in ophthalmic findings. Laboratory testing plays an important role in the diagnosis of genetic disorders and in carrier testing. Recent advances in cytogenetics, biochemical genetics, and molecular genetics have increased the understanding of many diseases and have allowed some to be defined at the molecular level. Concomitantly, new laboratory tests have been developed for several important hereditary eye diseases, including some forms of retinitis pigmentosa. These developments not only herald marked advances in the understanding of disease, they also introduce new legal and ethical issues that will affect the primary care clinician when using laboratory testing for genetic disease.

Clinical Laboratory Techniques↗
PubMed1991

Clinical and morphometric analysis of the hypoplastic corpus callosum.

A total of 307 children were evaluated over a 3-year period in our neurogenetics clinic. Review of their medical records demonstrated 26 patients with diagnoses of anomalies of the corpus callosum. Morphometric analysis was performed on those 23 patients qualitatively assessed as having a hypoplastic (small, but morphologically intact) corpus callosum. Morphometric data were compared with clinical correlates for each patient. From these data, we conclude that the hypoplastic corpus callosum is not a normal variant of development but rather an indicator of a more fundamental abnormality of cerebral development.

Agenesis of Corpus Callosum↗
PubMed1991

Role of fine catheter peritoneal cytology and laparoscopy in the management of acute abdominal pain.

Laparoscopy and fine catheter peritoneal cytology (FCPC) have been advocated as aids in the assessment of acute abdominal pain. In all, 411 patients admitted to a district general hospital during a 10-month period were managed using a standard protocol incorporating these techniques. After initial assessment by a surgical registrar, 151 patients were excluded from further progress through the protocol (age less than 16 years, definite diagnosis made or contraindication to FCPC. The remaining 260 patients were placed in one of four management groups: (A) urgent operation (23 patients); (B) 'look and see' (40 patients); (C) 'wait and see' (59 patients); (D) urgent operation not indicated (138 patients). Eighty-eight of 99 patients (88 per cent) in groups B and C, where the need for operation was uncertain, underwent successful FCPC and 39 patients (39 per cent) underwent laparoscopy. In these patients the initial registrar management decision proved to be incorrect in 33 cases (33 per cent), but by following the protocol the number of management errors actually made was reduced to 13 (13 per cent, P less than 0.001). This would have been reduced to 8 per cent if the protocol had not been violated in five patients. This study demonstrates the effectiveness of a protocol using FCPC and laparoscopy to improve the management of patients with acute abdominal pain.

Abdomen, Acute↗
PubMed1991

Evidence for balanced linkage of X chromosome polygenes in a natural population of Drosophila.

Extensive levels of polygenic variation can be maintained in a population without creating a severe segregational load. One way to account for this is that the alleles are arranged on a chromosome so that different regions balance each other phenotypically. To test whether this occurs in a natural population, we isolated ten Drosophila melanogaster X chromosomes and mapped regions of polygenic activity affecting sternopleural bristle number. The chromosomes fell into a small number of groups based upon the similarity of their distributions of polygenic activity. The results are consistent with a model in which a large proportion of the variation can be attributed to a small number of segregating chromosome regions and in which the chromosomes show internal balance.

Animals↗
PubMed1991

Age-related changes in the relative growth of the posterior fossa.

We have established a normative data set for the relative size of the structures of the midline posterior fossa from birth to 90 years old. Data were obtained from morphometric analysis of midsagittal magnetic resonance imaging scans of the brain utilizing a simple image analysis system. There are several significant changes in the size of these structures with an increase in chronologic age. The relative size of the cisterna magna decreases with age. Anterior cerebellar vermal lobules (I through V) appear to grow more rapidly than the rest of the cerebellum. Other, less significant, trends include a decrease in the overall size of the cerebellum, superior posterior vermal lobules (VI and VII) and inferior posterior lobule (VIII) with an increase in age. It is, therefore, necessary to use age-standardized normative data when making morphometric correlations with clinical disorders.

Adolescent↗
PubMed1990

Peritoneal fibrinolytic activity and intra-abdominal adhesions.

The mechanisms leading to reduction of peritoneal fibrinolytic activity in conditions that are associated with the formation of intra-abdominal adhesions were studied. Tissue plasminogen activator was found, by antibody inhibition techniques, to be the activator of fibrinolysis in homogenates of control peritoneum (n = 6). Homogenates of control (n = 10) and inflamed peritoneum (n = 10) were analysed. Plasminogen activating activity was much lower in inflamed peritoneum (median 0.07 IU/cm2) than in control tissue (median 12.0 IU/cm2) (p less than 0.001). Levels of tissue plasminogen activator and alpha 2-antiplasmin were similar in both control and inflamed tissue. Plasminogen activator inhibitor-1, not detectable in control peritoneum, was present in inflamed tissue and might be the reason for the reduction in functional fibrinolytic activity.

Abdomen↗