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Biomedical subjects

J Marsh

Publications and source records attributed to J Marsh.

At least 109 records · Page 6Linked to original sources
PubMed1987

Changes in CT service.

In summary, there has been a considerable change in the CT marketplace over the last six years. Some of these changes have definitely been an advantage to the patient and healthcare provider. Other changes may appear to be progress but, in reality, are a regression. Prior to committing significant expenditures for equipment or service, shop around for the company that best meets your needs. If you are unsure of your exact requirements or the implications of what you are hearing, ask an expert. These decisions involve considerable money and cannot be changed for a long time.

Cost-Benefit Analysis↗
PubMed1986

Antitumor activity in a rat mammary adenocarcinoma: the effect of cyclooxygenase inhibitors and immunization against prostaglandin E2.

Female Fischer 344 rats bearing the R3230AC mammary tumor were treated with three different inhibitors of cyclooxygenase--indomethacin, ibuprofen, and flurbiprofen (5 mg/kg body weight). After three weeks, the weight and volume of tumors from treated animals were smaller than those of control rats. Rats bearing the same tumor but immunized against PGE2 conjugated to bovine serum albumin showed similar trends in tumor growth inhibition. Thus we conclude that PGE2 plays an important role in the establishment and growth of the R3230AC mammary tumor.

Animals↗
PubMed1986

Transplantation of fetal fibroblasts and correction of enzymatic deficiencies in patients with Hunter's or Hurler's disorders.

An attempt was made at correcting the specific lysosomal enzyme deficiencies in 7 children with Hunter's or Hurler's diseases by transplantation of fetal fibroblasts. In spite of pretreating the young patients with stored blood, following a procedure employed successfully to avoid rejection of kidneys from incompatible donors, the use of serum-free media for culturing the cells before being harvested and incubation of the cells with chorionic gonadotrophin, the transplantation of fetal fibroblasts was not associated with biochemical or clinical changes. None of the seven patients showed immune reactions against the transplanted cells, HLA antigens, or the missing enzymes.

Animals↗
PubMed1986

The arylsulphatases of chorionic villi: potential problems in the first-trimester diagnosis of metachromatic leucodystrophy and Maroteaux-Lamy disease.

Three pregnancies at risk for late infantile metachromatic leucodystrophy have been monitored using chorionic villus biopsies. In the first of these a false negative diagnosis was made following assay of arylsulphatase A in villi. Subsequent studies have shown that this error was probably due to interference from another sulphatase in the villi, although the possibility that maternal contamination was also partly responsible could not be excluded. For reliable prenatal diagnosis of metachromatic leucodystrophy using chorionic villi it is advisable that studies with the nitrocatechol substrate are carried out on fractionated homogenates, or that the natural substrate is used. Problems may also occur when chorionic villi are used for assay of arylsulphatase B for first trimester diagnosis of Maroteaux-Lamy disease.

Arylsulfatases↗
PubMed1986

Low-dose PGI2 prevents monocrotaline-induced thromboxane production and lung injury.

In animals, monocrotaline induces an acute lung injury secondary to capillary endothelial damage. To date, no reports have appeared dealing with the role of prostaglandins in monocrotaline-induced injury. Our studies, in dogs, revealed that monocrotaline (30 mg/kg iv) caused an acute and persistent thrombocytopenia, lung platelet deposition, pulmonary hypertension, and increased extravascular lung water (EVLW). The pulmonary hypertensive response was biphasic. Thromboxane B2 levels were similarly biphasic, peaking at 5 min and 2 h. The levels of 6-keto-PGF1 alpha peaked at 30 min and returned to base line at 3 h. Pulmonary vascular resistance paralleled thromboxane levels. Infusion of prostacyclin (PGI2) at 50 ng X kg-1 X min-1 effectively prevented the thrombocytopenia, lung platelet deposition, pulmonary hypertension, and increased EVLW; and it decreased excess thromboxane production by 79%. These results suggest that platelet activation and lung sequestration play a role in acute lung injury due to monocrotaline, and that the resultant thromboxane production may contribute to the pulmonary hypertension. PGI2 ameliorates monocrotaline-induced injury, perhaps by preventing platelet activation.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Growth inhibition and eicosanoid metabolism in the R3230AC mammary adenocarcinoma by interferon.

The mode of action of rat interferon (IFN) on growth of the R3230AC mammary adenocarcinoma was studied in vivo in Fischer female rats. A dose of 1 X 10(4) units of rat IFN given thrice weekly inhibited the growth of the transplanted mammary tumors. Of the five eicosanoids measured in the tumor, the content of four arachidonate products, prostaglandin (PG) E2, PGF2 alpha, 6-keto-PGF1 alpha, and thromboxane (TX) B2, was higher in mammary tumors from IFN-treated rats than the control rats. PGE2 was the major eicosanoid. In vitro PG synthesis (PGE1, PGE2, and PGF2 alpha) was lower in tumor microsomes prepared from IFN-treated tumors. These data suggest that the tumor content of four arachidonate products in the IFN-treated tumors was related to the in vivo effects of rat IFN. Indomethacin, a cyclooxygenase inhibitor, also inhibited tumor growth. Furthermore, when indomethacin was administered daily in combination with rat IFN, the tumor-inhibiting effect of rat IFN was reduced. These observations suggest that the effects of eicosanoids appear to be biphasic in this tumor model. Inhibition of arachidonic acid metabolism resulted in tumor growth inhibition, a finding consistent with the view that eicosanoid production is required for tumor enhancement. Conversely, in the experiments with rat IFN, retardation of tumor growth is associated with a greater amount of arachidonic acid metabolism, and indomethacin prevents this effect. Eicosanoids appear to be required for tumor-inhibiting effects of rat IFN, and yet inhibition in vivo of eicosanoid synthesis also resulted in retardation of tumor growth. Although the precise mechanism of action in each situation is unclear, these apparently contradicting results are consistent with the biphasic actions of eicosanoids reported in some normal tissues and transformed tumor cell lines.

Adenocarcinoma↗
PubMed1986

Histocompatible unrelated volunteer donors compared with HLA nonidentical family donors in marrow transplantation for aplastic anemia and leukemia.

We treated 14 patients by transplantation of marrow from unrelated volunteer donors. Eight patients had severe aplastic anemia, 3 had chronic granulocytic leukemia, and 3 had Fanconi's anemia. The results are compared with those of a group of 14 similar patients transplanted concurrently from human leukocyte antigen (HLA)-mismatched family members: Sustained engraftment was achieved in 8 of 14 patients in both groups; one additional patient survived with autologous marrow reconstitution following an unrelated donor transplant. In the unrelated donor group, 6 of 9 evaluable patients developed grade III through IV acute graft-v-host disease, as compared with 4 of 9 patients after family-mismatched transplants. Overall survival was similar in the two groups. In the unrelated donor group 4 of 14 (29%) patients survived (median survival 1,299 days) as compared with 5 of 14 (36%) in the mismatched-family donor group (median survival 808 days). In both groups, patients with HLA phenotypically matched donors fared better than those with donors who were mismatched for one or more HLA antigen. Of the patients transplanted from HLA phenotypically matched donors 6 of 12 patients (50%) survived, as compared with 3 of 16 patients (19%) transplanted from HLA-mismatched donors. We conclude that unrelated donor bone marrow transplantation (BMT) should be considered in those cases of leukemia or bone marrow failure in which the chance of cure using conventional therapy is remote and a HLA genotypically or phenotypically matched family donor is not available.

Anemia, Aplastic↗
PubMed1985

Antitumor activity in a rat mammary adenocarcinoma: the effect of cyclooxygenase inhibitors and immunization against prostaglandin E2.

Female Fischer 344 rats bearing the R3230AC mammary tumor were treated with three different inhibitors of cyclooxygenase--indomethacin, ibuprofen, and flurbiprofen (5 mg/kg body weight). After three weeks, the weight and volume of tumors from treated animals were smaller than those of control rats. Rats bearing the same tumor but immunized against PGE2 conjugated to bovine serum albumin showed similar trends in tumor growth inhibition. Thus we conclude that PGE2 plays an important role in the establishment and growth of the R3230AC mammary tumor.

Adenocarcinoma↗
PubMed1985

Selective sparing of enterochromaffin cells in graft versus host disease affecting the colonic mucosa.

Graft versus host disease affecting the large bowel causes destruction of the crypt epithelium. There is a selective sparing of enterochromaffin cells in the majority of cases. As a consequence, single as well as small clumps of enterochromaffin cells are to be seen in the sites formerly occupied by the destroyed crypt epithelium. The reason for this phenomenon is unclear, but it may be related to the fact that the enterochromaffin cells are end-stage and non-proliferating cells. This is useful diagnostically. However, cytotoxic drugs or irradiation must be excluded as the cause of the mucosal damage to bowel as there are theoretical reasons to expect that a similar phenomenon will be seen after these forms of therapy.

Adolescent↗
PubMed1985

4-Methylumbelliferyl alpha-N-acetylglucosaminidase activity for diagnosis of Sanfilippo B disease.

Conditions for assay of alpha-N-acetylglucosaminidase activity in human cultured fibroblasts, cultured amniotic fluid cells, leucocytes, serum, plasma and chorionic villi were studied using the fluorogenic substrate 4-methylumbelliferyl-2-acetamido-2-deoxy-alpha-D-glucopyranoside. The substrate was found to have advantage both in terms of sensitivity and ease of use over previously-used colorimetric substrates for assay of the enzyme in these tissues, and for diagnosis of Sanfilippo B disease and identification of carriers. It should have particular application in first trimester prenatal diagnosis using chorionic villus biopsies.

Acetylglucosamine↗
PubMed1985

Plasma concentrations of somatomedin-C in hypophysectomized, dwarf and intact growing domestic fowl as determined by heterologous radioimmunoassay.

The application of a human somatomedin-C radioimmunoassay for the determination of somatomedin-C in chicken plasma has been examined. Parallel inhibition of binding of 125I-labelled somatomedin-C to antisera raised against somatomedin-C was observed with acid-treated human and chicken plasma. The concentration of immunoreactive (IR)-somatomedin-C in the plasma of the domestic fowl appears to be GH dependent. Plasma concentrations of IR-somatomedin-C were reduced after hypophysectomy and partially restored by replacement therapy with chicken GH. The age/development pattern of circulating concentrations of IR-somatomedin-C has been determined in normal and dwarf strains of domestic fowl. Increases in the plasma concentration of IR-somatomedin-C were observed between 1 and 6 weeks of age in control male domestic fowl of either heavy (broiler type) or light (White Leghorn) strains. Thereafter, the plasma concentrations of IR-somatomedin-C remained constant in the heavy strain birds but declined in White Leghorn chicks. Plasma concentrations of IR-somatomedin-C were reduced in sex-linked dwarf chickens, in both light and heavy strains of fowl, but were unaffected in autosomal dwarf chickens.

Animals↗
PubMed1985

Transplantation of amniotic epithelial membranes in patients with mucopolysaccharidoses.

This paper reports the biochemical results of transplanting human amniotic epithelial cells in 3 children with Hunter's and 2 with Hurler's disease. A transient and modest increase of alpha-L-idurono-2-sulphate sulphatase or alpha-iduronidase was observed in the white cells collected from 1 patient with Hunter's and 1 with Hurler's disease. No variation in the excretion of glycosaminoglycans or oligosaccharides was detected in all 5 patients. There was no evidence of immune response towards the transplanted cells or the specifically deficient enzyme. Thus, in spite of the absence of the major histocompatibility antigens, HLA A, B, C and DR, on the surface of the amniotic epithelial cells, no long-term correction of lysosomal enzyme deficiencies was achieved by transplanting amniotic epithelial membranes collected at the end of the gestational period.

Amnion↗
PubMed1984

Effect of omega-3 fatty acids on growth of a rat mammary tumor.

The effect of administering marine oil that was rich in omega-3 fatty acids on tumor growth was studied in female inbred F344 rats that received transplants of R3230AC mammary adenocarcinoma. Four groups of rats were maintained on a normal rat chow diet containing 5% fat, and marine oil supplementation was started 1 week prior to transplantation of the tumors. The marine oil provided 17, 33, and 67 mg of 5, 8, 11, 14, 17-eicosapentaenoic acid (EPA) and 16, 32, and 64 mg 4, 7, 10, 13, 16, 19-docosahexaenoic acid (DHA) a day. A significant reduction in weight (g) and volume (cm3) of the rat R3230AC mammary tumor was observed after 4 weeks of treatment. EPA (20:5 omega-3) and DHA (22:6 omega-3) were found in choline phospholipid fractions of mammary tumors from rats given marine oil. Both tumor content and synthesis in vitro of prostaglandins of two series were inhibited in the marine oil-treated groups. These data indicated that the mechanism underlying inhibition of mammary tumorigenesis may be linked, in part, to the inhibitory effect of both EPA and DHA on arachidonic acid metabolism.

Adenocarcinoma↗
PubMed1984

Analysis and interpretation of turning points and run lengths in breath-by-breath ventilatory variables.

Three healthy young male volunteers were studied for 10 min periods of steady-state ventilation under the following conditions: air breathing, 50% inspired oxygen, hyperoxic hypercapnia and hypoxic hypercapnia. Eight variables were recorded breath-by-breath: inspiratory and expiratory tidal volumes, mean flows and durations, total breath duration and expiratory ventilation. Each resulting sequence of breath-by-breath data was analysed in terms of the number of 'turning points' in the sequence and the concomitant mean 'run length' between turning points. The mean run length for all these variables was 1.600, 1.599 and 1.592 in the three subjects. These values are significantly greater than the expected value of 1.5 for random data sequences. There were no consistent significant differences between variables or subjects. Under conditions of hypoxic hypocapnia the mean run length of all variables was found to be 1.666, 1.724 and 1.568 in the three subjects. The two higher values corresponded with periodic breathing of period 10-30 s. These observations are lower than previously published values. A number of ways of interpreting a mean run length of greater than 1.5 are suggested.

Adult↗
PubMed1984

Characteristics of cultured lung fibroblasts from bleomycin-treated rats. Comparisons with in vitro exposed normal fibroblasts.

Bleomycin is an antineoplastic agent that causes pulmonary fibrosis. This report describes fibroblasts cultured from lung tissue explants of in vivo bleomycin-exposed and control rats. Proliferation of cultured fibroblasts from bleomycin-exposed lungs was decreased compared with that from control cultures, both in rate of growth and maximal cell yield. The diminished proliferative capacity of these fibroblasts from exposed lungs persisted over 9 wk of serial subcultivation. Fibroblast cultures from exposed lungs typically had a greater proportion of large cells exhibiting extensive cytoskeletal structures than did control cultures. Comparisons of these fibroblasts with normal fibroblasts exposed in vitro to bleomycin showed similarities in size, morphologic features, and proliferation.

Animals↗