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Biomedical subjects

P Harper

Publications and source records attributed to P Harper.

At least 145 records · Page 8Linked to original sources
PubMed1986

Spectrophotometry of carnitine in biological fluids and tissue with a Cobas Bio centrifugal analyzer.

A spectrophotometric method for carnitine has been adapted to the Cobas Bio centrifugal analyzer. The addition of carnitine to a system containing carnitine acetyltransferase (EC 2.3.1.7) and acetyl-CoA gives rise to the formation of CoA. The system is coupled to 5,5'-dithiobis(2-nitrobenzoate) (DTNB). Assay response varied linearly with concentration of carnitine over a wide concentration range. The total CV was 5.5% for a carnitine concentration in serum of 58.0 mumol/L. Analytical recovery of carnitine added to a serum sample was 93%. No interference was found in icteric, not grossly hemolyzed, lipemic, or uremic sera. Comparison with a radioenzymatic method showed that results correlated well (r greater than 0.965) but the present method gave values proportionally greater by 10 to 25% for samples of plasma, dialysis fluid, urine, and muscle tissue. Advantages over the original spectrophotometric assays involving DTNB include low reagent costs, rapidity, simplicity, and reproducibility. However, this modification is not as sensitive and probably not as specific as the radioenzymatic methods.

Acetylcarnitine↗
PubMed1985

Culture of sweat gland epithelial cells from normal individuals and patients with cystic fibrosis.

Recent electrophysiological and pharmacological studies have confirmed previous clinical evidence that the gene defect in cystic fibrosis is strongly expressed in the sweat gland. This has provided a major impetus to efforts to culture the cells of this tissue in order to provide a source of experimental material for molecular studies. Toward this end, eccrine sweat glands were isolated from collagenase treated skin specimens and the secretory coil and the reabsorptive duct separated. Segments of each portion of the gland were transferred to a plastic or collagen substrate and covered with serum-containing or serum-free defined growth media. Epithelial cell outgrowth took place in both media but fibroblast overgrowth occurred in the presence of serum at concentrations as low as 1%. In serum-free medium both secretory and reabsorptive cells formed tightly joined epithelial sheets, first as monolayers and later as multilayers consisting of at least six cell layers. Growth continued for approximately fifteen generations each of about two and a half days. Remarkably large domes or hemicysts with diameters as great as two cm were formed, apparently attesting to the retention of the capacity of the cells to actively transport ions and water. Ultrastructurally, cells which grew out from the secretory coil resembled the fluid secreting clear cells; neither dark cells nor myoepithelial cells were propagated.

Cell Division↗
PubMed1985

Determination of cholesteryl sulphate by isotope dilution-mass spectrometry for diagnosis of steroid sulphatase deficiency.

A specific and accurate method for determination of cholesteryl sulphate in serum based on isotope dilution-mass spectrometry has been developed. 2H-labelled cholesteryl sulphate was synthesized and used as internal standard. After addition of the internal standard to serum, the cholesteryl sulphate is extracted with butanol and purified by thin-layer chromatography. The material is then solvolysed, converted into trimethylsilyl ether, and analysed by combined gas chromatography-mass spectrometry. The ratio between unlabelled and labelled cholesterol is determined by selected ion monitoring of the ions at m/e 458 (corresponding to the molecular ion of derivative of unlabelled cholesterol) and m/e 465 (corresponding to the molecular ion of derivative of 2H7-labelled cholesterol). The concentration of cholesteryl sulphate is calculated with use of a standard curve. The coefficient of variation of the method was found to vary between 4% and 9% in different concentration ranges. Nine healthy male infants (age range, 1-3 yr) had concentrations of cholesteryl sulphate varying between 0.2 and 11 mumol/l (mean, 3.8 mumol/l). A boy with suspected steroid sulphatase deficiency had a concentration of cholesteryl sulphate of 69 and 64 mumol/l at the age of 12 and 18 months, respectively.

Adult↗
PubMed1984

Disseminated gastrointestinal sarcoidosis. Case report and review of the literature.

A patient with long-standing sarcoidosis was found to have jejunal atrophy and nonnecrotizing granulomas of the stomach, small bowel, and colon when she presented with malabsorption. There were no radiologic abnormalities of the gastrointestinal tract. Symptoms of malabsorption rapidly abated with corticosteroid treatment given for severe pulmonary disease. Gastrointestinal sarcoidosis was clearly established, although coincident celiac sprue could not be excluded. A brief discussion and literature review of gastrointestinal sarcoidosis is included.

Diarrhea↗
PubMed1983

T cell regeneration after allogeneic and autologous bone marrow transplantation.

Venous blood T cell phenotypes were analysed with monoclonal antibodies after 11 allogeneic and 17 autologous bone marrow transplants. In seven cases studied in the early regenerative period, cells with a thymocyte phenotype were present in the blood. In the large majority of patients treated with both allografts and autografts there was an imbalance of phenotypic 'helper' and 'suppressor' T cell subsets with initially a relative and later an absolute increase of 'suppressor' T cells. This imbalance was still present at over 250 d in eight out nine cases. Suppressor T cells bearing HLA-Dr antigens were abundant in one case of fatal GVHD but not in another, and were also increased following two autografts. It is concluded that T cell phenotyping is not of diagnostic value in sick patients following bone marrow transplantation when graft-versus-host disease is suspected.

Adolescent↗
PubMed1982

The Mendelian inheritance of a human X chromosome-specific DNA sequence polymorphism and its use in linkage studies of genetic disease.

A recombinant DNA sequence, lambda RB6, was isolated from a human X chromosome library and shown to be X-specific by hybridisation to DNA from a human-mouse somatic cell hybrid containing X as the only human chromosome. The cloned sequence was located on the long arm distal to Xq13 using a human-mouse somatic cell hybrid containing a partial human X chromosome. DNA samples isolated from control human females were digested with the restriction enzyme MspI, and analysed by "blotting" and hybridisation to the radioactive cloned DNA. Eight of 14 individuals from a random population showed a single hybridising band 7.5 kilobase pairs (kb) in length, but six showed an additional band 10.1 kb in length. DNA from 12 members of a family with X-linked thyroxine-binding globulin deficiency was analysed for the segregation of this polymorphism. The results show that the polymorphism is inherited in a Mendelian fashion, and that the disease locus is not closely linked to the polymorphic site. Such polymorphisms will be useful as markers for chromosome mapping and for the antenatal diagnosis of genetic diseases.

Animals↗
PubMed1981

Angiosarcoma of the liver: a signal lesion of vinyl chloride exposure.

Vinyl chloride (VCM) induced angiosarcoma of the liver (ASL) is a rare vascular tumor which might be associated with a wide range of disease states. The possibility that this tumor might be a signal lesion is supported by mortality studies suggesting that cancers of the digestive, respiratory, neurological and lymphatic systems have occurred more often than expected in VCM workers. There is also evidence that certain non-neoplastic disorders, such as pneumoconiosis and excess fetal deaths, may be associated with this chemical. It has been suggested that a gradual increase in the incidence of ASL might have occurred in recent years. This could be a reflection of the long latency period and/or the increased recognition of this entity. Several cases of ASL have occurred in people living in the vicinity of VCM plants. This raises the possibility that low-level exposure to this chemical over a long period might induce ASL.

Adolescent↗
PubMed1980

Radiology of the pelvis and hips in adults with Down's syndrome.

In a radiological study of the pelvis in 66 adult subjects with Down's syndrome, 25 (38%) were found to have the classical pelvic sharpe associated with Down's syndrome in infancy and childhood. The appearance of the pelvis and hip joints was very variable and matched the variety of appearances seen in normal subjects, except that generally the pelvis was smaller than normal. The discriminating value of the iliac index (which is abnormal in up to 80% of affected infants) was lost in this group of affected adults. Subluxation and osteoarthrosis of the hips were very uncommon features. In addition to the primary morphological abnormalities in the pelvis in Down's syndrome that are described in the literature, posture probably plays a part in producing the variable radiological appearances of the pelvis.

Adult↗
PubMed1980

Ultrasound visualization of the breast in symptomatic patients.

More than 400 breast patients (primarily symptomatic) have been examined with ultrasound alone and in combination with low-dose mammography. Symptomatic pregnant women and young patients with palpable masses were examined with ultrasound alone. In young, dense breasts, ultrasound was found to surpass mammography in the differential diagnosis of both cystic and solid masses. In older patients, the tumor characteristics displayed on ultrasound augmented those of mammography, resulting in increased diagnostic accuracy.

Adenofibroma↗
PubMed1977

Angiosarcoma of the liver: an epidemiologic survey.

Diagnosed from 1970 through 1975, the annual incidence rate for angiosarcoma of the liver among residents of New York State (excluding New York City) was 0.25 per million. A case-control study indicated that direct exposure to arsenic, vinyl chloride (VC), and thorium dioxide was a significantly important factor in the etiology of this disorder (P less than 0.02). Direct exposure to these chemicals could not be demonstrated for 19 (73%) of the 26 study patients. The fact that 5 of these patients lived nearer to VC fabrication or polymerization plants than did their matched controls lent some support to the hypothesis that indirect modes of exposure, not specifically related to occupation, might be important in the etiology of this disorder.

Adolescent↗