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Biomedical subjects

J M Sheat

Publications and source records attributed to J M Sheat.

9 recordsLinked to original sources
PubMed1993

Circulating proalbumin associated with a second case of antitrypsin Pittsburgh.

We report here the conclusive identification of circulating proalbumin of normal N-terminal sequence (Arg Gly Val Phe Arg Arg Asp Ala) in a second child with the alpha 1-antitrypsin Pittsburgh 358 Met-->Arg mutation. As in the first case, the proalbumin made up 3-5% of the total serum albumin. The finding of proalbumin associated with a second de novo mutation at the inhibitory site bait of antitrypsin confirms our earlier hypothesis; that antitrypsin Pittsburgh was acting as a specific intracellular inhibitor of the hepatic proalbumin convertase and that antitrypsin Pittsburgh could be used as a probe to identify the proprotein convertase.

Amino Acid Sequence↗
PubMed1991

Rapid detection and initial characterization of genetic variants of human serum albumin.

We have studied the detection and classification of genetic variants of human serum albumin by electrophoresis. Samples from 10 patients who were heterozygous for eight different albumin variants were studied by two methods. In agarose gel electrophoresis, each of these variants has an abnormal mobility and can be classified on the basis that structural changes at the N-terminus abolish 63Ni binding. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole serum, glycosylated variants are easily detected because of their greater apparent molecular mass.

Autoradiography↗
PubMed1990

Methylprednisolone in multiple sclerosis exacerbation: changes in CSF parameters.

Twenty-six patients with multiple sclerosis (MS) received a total of 45 courses of intravenous methylprednisolone daily for seven days, for acute neurological deterioration. Changes in CSF parameters and clinical status following methylprednisolone were determined and first and repeat courses were compared. There were significant reductions in CSF IgG, CSF albumin, serum IgG and serum albumin levels and CSF IgG synthesis rate in the first and repeat treatment groups. CSF IgG index fell significantly with initial methylprednisolone treatment but not with subsequent courses. Oligoclonal bands disappeared in three patients. Definite clinical improvement followed 30 methylprednisolone courses, possible improvement followed six and no change followed seven. Clinical response was not predicted by pre-treatment CSF IgG synthesis status and did not correlate with its degree of reduction.

Adult↗
PubMed1988

Multiple sclerosis: problems in the evaluation of intrathecal IgG synthesis.

We report two patients with multiple sclerosis which illustrate problems in the interpretation of the cerebrospinal fluid (CSF) protein studies used to confirm diagnosis. In one case a polyclonal increase in IgG synthesis, secondary to an aseptic meningitis, masked oligoclonal banding, which was confirmed on subsequent examination. In the second case, despite a normal quantitative intrathecal IgG synthesis rate, oligoclonal banding in the CSF confirmed abnormal intrathecal synthesis of IgG. These cases show the value of combining a quantitative index of intrathecal IgG synthesis with examination for oligoclonal banding and illustrate their interpretation.

Adult↗
PubMed1988

Detection of protein binding abnormalities in euthyroid hyperthyroxinemia.

This is a procedure for rapidly identifying the three common abnormalities in binding of thyroxin by protein. After incubation with [125I]thyroxin, serum proteins are separated by electrophoresis on agarose gel and binding of thyroxin to the various protein fractions is determined after autoradiography. Quantitatively abnormal binding to albumin or prealbumin and thyroxin autoantibodies is easily demonstrated by this technique. Normally, less than 6% is bound to albumin, and no binding by prealbumin is detected. In dysalbuminemic hyperthyroxinemia, about 30% of the serum thyroxin is bound to albumin; in prealbumin-associated hyperthyroxinemia, 7% is bound to prealbumin. With this procedure these protein-binding abnormalities can be simply identified, and it may be useful when results of a thyroxin assay are not consistent with results of a sensitive thyrotropin assay or the patient's clinical examination.

Autoantibodies↗
PubMed1987

A simple silver-staining technique for detecting Bence Jones proteins in unconcentrated urine.

Detection of Bence Jones proteins in urine usually involves a concentration step, followed by electrophoresis and, if necessary, immunofixation. The time-consuming and expensive concentration step can be eliminated by use of the silver-stain technique described here. This procedure, routinely used for staining unconcentrated urine, is inexpensive, sensitive, and easily performed in a clinical laboratory. Bence Jones proteins can be detected in concentrations as low as 5 mg/L.

Bence Jones Protein↗
PubMed1979

Familial relative polycythaemia due to haemoglobin Heathrow.

Eleven affected members of a New Zealand family carrying the high oxygen affinity haemoglobin Heathrow are described. The detection of high oxygen affinity abnormal haemoglobins may be difficult as haemoglobin and red cell mass may both fall within the normal range and no abnormality may be detected on haemoglobin electrophoresis or by haemoglobin stability tests. The importance of oxygen affinity studies to establish the diagnosis is emphasized.

Adult↗
PubMed1975

Alpha-1-antitrypsin variants in New Zealand.

Twelve percent of a sample of New Zealand Europeans were found to have variant forms of alpha-1-antitrypsin. The distribution of different variants was similar to that found in other Northern European populations. Four percent were heterozygotes for the deficiency state (Z allele) which predisposes to both emphysema and cirrhosis. An initial survey of New Zealand Maoris suggests that although they have a lower overall incidence of variants, there is an increased frequency of the deficiency Z allele. This may be a contributory factor to the susceptibility of the Maori to respiratory and liver disease.

Adult↗