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Biomedical subjects

J E Scott

Publications and source records attributed to J E Scott.

At least 91 records · Page 5Linked to original sources
PubMed1993

Violence and sexual violence in pornography: is it really increasing?

Literature and research on the question of the increasingly violent nature of pornography is reviewed. In addition, the paper reports the findings of a content analysis of all cartoons and pictures in Hustler Magazine from 1974 through 1987. Results indicate that sexually violent cartoons and/or pictorials constitute a relatively small proportion of the total cartoons and pictorials. Moreover, no monotonic increase was found in such depictions over the 14-year period examined. In fact, a relatively small and constant proportion of violent and/or sexually violent depictions over this period is reported. These findings are examined in relation to previous research and societal concern about alleged increases in violent pornography as an explanation for increases in rape rates.

Erotica↗
PubMed1993

Production of fibroblast-pneumocyte-like factor by fetal rabbit lung fibroblasts: isolation and effects of it and related factors on fetal type II cells in vitro.

Fetal lung fibroblasts interact with type II epithelial cells, inducing their maturation. This interaction arises by secretion of factors which alter fetal type II cell function. To analyze these factors, conditioned medium (CM) was produced by exposing serum-free minimum essential medium, with [35S]methionine (5 microCi/ml), to confluent cultures of fetal rabbit lung fibroblasts. This medium was tested for ability to stimulate [3H]choline incorporation by fetal type II cells and subsequently fractionated on molecular weight filtration columns P60 (2.5cm x 90cm; NMW cutoff, 60kd; 1M acetic acid) and A1.5m (2.5cm x 90cm; NMW cutoff, 1,500kd; Tris-buffered saline) and a hydroxyapatite column (HT) (1.5cm x 30cm; NaCl and 0.01-0.3M phosphate). Crude medium stimulated choline incorporation into phosphatidylcholine. [35S]methionine was resolved in void volume material and in material of apparent molecular weight of 6000 daltons on the P60 filtration column. Filtration on the A1.5m column showed two major fractions with radiolabel incorporation. Each of these was resolved into two subfractions on HT chromatography. The high molecular mass fraction contained material which stimulated [3H]choline incorporation by fetal type II cells. The low molecular mass fraction tended to inhibit [3H]choline incorporation. The second subfractions of both the first and second primary fractions inhibited [3H]thymidine incorporation into DNA by fetal type II cells. SDS-PAGE electrophoresis and autoradiography showed that under reducing conditions, each peak contained several proteins. However few of these displayed radioactivity. These results indicate that protein factors produced by fetal lung fibroblasts may be involved in regulating both differentiation and replication of fetal type II cells.

Animals↗
PubMed1993

A phase II and pharmacokinetic study with oral piritrexim for metastatic breast cancer.

Piritrexim is a lipid-soluble antifolate which, like methotrexate, has a potent capacity to inhibit dihydrofolate reductase. We performed a multicentre phase II study with piritrexim in patients with locally advanced or metastatic breast cancer. Twenty-four patients of which sixteen had received prior chemotherapy, were initially treated with 25 mg piritrexim orally administered trice daily for four days, repeated weekly, with provision for dose escalation or reduction according to observed toxicity. Of twenty-one patients evaluable for tumour response, one patient achieved a partial response which lasted for 24 weeks. Three patients had stable disease during 12 weeks of treatment, seventeen had progressive disease. Pirtrexim was generally well tolerated, in eighteen patients the dose could be escalated. Myelotoxicity was the most frequent observed toxicity of this piritrexim regimen. Leucopenia and thrombocytopenia grade 3/4 occurred in 38% of the patients sometime during treatment. Pharmacokinetic analysis of piritrexim in three patients during the first treatment cycle, revealed peak levels 1 to 2 h after an oral dose, with a trend towards a higher peak plasma levels and AUCs on the fourth dosing day compared with the first dosing day. In conclusion, orally administered piritrexim appears to be a regimen with little activity in patients with locally advanced or metastatic breast carcinoma.

Administration, Oral↗
PubMed1993

Fetal ureteric reflux: a follow-up study.

The findings in 21 children (17 males) with ureteric reflux diagnosed in the first 3 months of life and likely to have been present antenatally are described; 19 were followed up for between 2 and 8 years. Reflux was grade 3 and bilateral in 13 babies. Radioisotope studies showed evidence of renal parenchymal abnormalities in 45% of non-infected refluxing kidneys. Nonoperative treatment was adopted initially. The reflux disappeared completely in 6 children: evidence that it would do so was apparent within 2 years. Two children developed pelviureteric junction obstruction that was secondary to the dilatation accompanying the reflux. Anti-reflux surgery was performed in 10 children because the degree of reflux and upper urinary tract dilatation were increasing. Operative treatment for fetal ureteric reflux of advanced grades should be considered if there is no improvement after 2 years; gigantic reflux may otherwise ensue.

Female↗
PubMed1993

Urological anomalies in the Northern Region Fetal Abnormality Survey.

From 1 January 1985 to 31 December 1990, the Northern Region Fetal Abnormality Survey received 736 notifications of fetuses with suspected urological abnormalities; a prevalence of three per 1000 births. There was a male:female ratio of 2:1, the ratio was higher in obstructive than in intrinsic renal parenchymal lesions. Overall diagnostic sensitivity was 68.9% and positive predictive value 50.8%. Hydronephrosis was the most frequent antenatal diagnosis (421 cases, 57.2%): 233 (55.3%) of these were found to be normal postnatally. There were 52 other false positive diagnoses. Of 113 babies with confirmed hydronephrosis antenatal diagnosis was correct in 97, sensitivity 85.8%, specificity 48.1%; 1.8% of these had chromosome defects. In 33 cases of bilateral renal agenesis antenatal diagnosis was correct or potentially correct in 24, sensitivity 72.7%, specificity 98.9%. Only six of 26 babies with posterior urethral valves were suspected, sensitivity 23%, specificity 98.7%. Mortality rate in 91 babies with unsuspected abnormalities was 39.6%: overall mortality was 24.2%. Unsuspected abnormalities occurred more frequently when mothers were not scanned after the 16th week of pregnancy.

Chromosome Aberrations↗
PubMed1993

Influence of strain on [3H]thymidine incorporation, surfactant-related phospholipid synthesis, and cAMP levels in fetal type II alveolar cells.

Episodic fetal breathing movements occur in utero; however, their purpose is not known. While some evidence indicates these movements produce distention of the fetal lung, the effects of eliminating the movements on lung development are not clear. Using preparations of the surfactant-producing fetal rabbit lung type II cells, we have examined the hypothesis that distention is involved in maturation of these cells as determined by replication rate and phospholipid synthesis. Differentiating type II cells were isolated from fetal rabbit lungs on gestational day 24. After allowing 24 h for the cells to attach, distention (10%) was applied using a Flexercell apparatus at a rate of 3 s of strain and 57 s of rest for 24 or 48 h. Cells were concurrently incubated with [3H]thymidine. Autoradiography showed that [3H]thymidine-labeled nuclei of fetal type II cells and fibroblasts could be identified. Strain significantly increased incorporation of the radioisotope into DNA. In the remaining studies, cells were grown to confluence prior to use. Cell viability after straining (3 or 50 cycles per minute [cpm] for 48 h) was assessed by incubating with diacetyl fluorescein/ethidium bromide and viewing by fluorescence microscopy. Straining did not alter cellular viability. Lactate dehydrogenase was also assayed in the culture medium. Straining did not cause release of lactate dehydrogenase. Ultrastructural examination showed typical cellular appearance in the strained cells. Extracellular lamellar body material was also observed. The incorporation of [3H]choline (3 or 50 cpm) into cellular phospholipids was measured under static conditions or under distention. [3H]choline-labeling of phosphatidylcholine and disaturated phosphatidylcholine was significantly increased by distention at either 3 or 50 cpm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Ultrastructural and biochemical observations on proteoglycans and collagen in the mutable connective tissue of the feather star Antedon bifida (Echinodermata, Crinoidea).

Mutable connective tissue, unique to echinoderms, changes its mechanical behaviour within seconds of nervous stimulation. The molecular mechanism of this phenomenon is not understood. In this study proteoglycans and collagen of the brachial ligaments connecting neighbouring ossicles of the arms of the feather star Antedon bifida have been investigated by biochemistry, light and electron microscopy and the critical electrolyte concentration (CEC) technique using the dye Cupromeronic Blue (CB). The ligaments consist mainly of parallel cross-striated collagen fibrils, 82 +/- 12 nm in diameter, with a characteristic banding pattern and a D-period of 52.8 +/- 3.2 nm. Some fibrils were disaggregated into bundles of 10-11 nm protofibrils, lying between the normal fibrils. Proteoglycans occur at the surface of the fibrils with 2 binding sites (each with a different CEC) per D-period and also inside the fibrils. The surface proteoglycans are more highly sulphated (i.e. their CECs are > 1.3 M) than the intrafibrillar proteoglycans (CEC < 0.9 M). The glycosaminoglycans consist of a highly sulphated chondroitin sulphate, possibly with fucose residues. The results are consistent with the theory that disaggregation of the fibrils into protofibrils and reaggregation might be a mechanism of mutability, without excluding the possibility that fibrils may slide alongside each other during movements in the viscous phase of the ligament.

Animals↗
PubMed1992

Secondary and tertiary structures involving chondroitin and chondroitin sulphates in solution, investigated by rotary shadowing/electron microscopy and computer simulation.

Rotary shadowing/electron microscopy of chondroitin 6-sulphate (CS6) and 4-sulphate (CS4) showed that the former, but not the latter, aggregated to mesh works. Preparations made from salt (ammonium acetate) solutions showed enhanced aggregation. Computer modelling, using molecular mechanics and dynamics, was applied to secondary structures (twofold helices) derived from NMR studies, to determine geometric and energetic constraints on duplex and higher-aggregate formation. The calculations suggested that chondroitin, CS6 and undersulphated CS4 could form duplexes, while CS4 could not, thus bridging the gap between atomic dimensions (NMR) and high polymer scale (electron microscopy). Calculations suggested that water structure helped to stabilise the twofold helix. It is proposed that the twofold helical, flat, tape-like molecules aggregate via hydrophobic bonding between the very extensive hydrophobic patches (9 CH units) repeated on alternating sides of the polymers. The negative charge of the polyanions opposes aggregate formation. Calculations showed that duplexes were formed with decreasing stability as the charge density increased, and as the charge was concentrated towards the centre line of the polymer (i.e. in CS4). The unsulphated polymer chondroitin could form duplexes and higher aggregates as readily as hyaluronan. Hyaluronan was calculated to form stable heteroduplexes with CS6 and CS4. The frequency and positioning of the sulphate-ester group within the polymer thus determines whether the molecule participates in duplex formation.

Animals↗
PubMed1992

Effect of oxygen tension and lactate concentration on keratan sulphate and chondroitin sulphate biosynthesis in bovine cornea.

Calf cornea slices were incubated with [U-14C]glucose, in varying pO2 or lactate concentrations. Acid glycosaminoglycans were separated by ion-exchange chromatography after papain digestion. The percentage radioactivity incorporated into keratan sulphate increased markedly with decreased oxygen tension, whereas a concomitant relative decrease of the biosynthesis of glycosaminoglycuronans occurred. Similar results were obtained with increased lactate concentration. Our findings support the idea that keratan sulphate is a functional substitute for chondroitin sulphate in conditions of oxygen lack (Scott, J.E. and Haigh, M. (1988) J. Anat. 158, 95-108).

Animals↗
PubMed1992

A survey of state insurance mandates covering alcohol and other drug treatment.

This article reports the results of a survey of health insurance mandate legislation for alcohol and other drug treatment in the 50 states through spring 1991. A total of 23 states (including the District of Columbia) requires insurance carriers to provide coverage for alcohol and other drug treatment. This paper compares the provisions in these states at the present time and contrasts these provisions with those in effect in 1981. The paper concludes with a discussion of the policy objectives states pursue through enactment of such legislation and the outcomes brought about by the mandates.

Alcoholism↗
PubMed1992

GTP-related effects and binding by differentiating fetal rabbit type II alveolar cells in vitro.

Type II alveolar cells were isolated from fetal rabbit lungs and used to determine the effect of GTP-binding protein activation on release of surfactant-related material. Cells were prelabelled with [3H]choline for 24 hours. NaF, a G-protein activator and GTP gamma S, a nonhydrolysable analogue of GTP, both loaded by hypoosmotic shock treatment, stimulated release of radioactive disaturated phosphatidylcholine. Localization of the cellular binding of [alpha-32P]GTP in fetal type II cells which were induced to differentiate by exposure to fetal lung fibroblast conditioned medium showed that two proteins of apparent molecular weights of 39.6 kd and 17.9 kd bound [alpha-32P]GTP. These proteins were detected only in the cells exposed to the conditioned medium. These results suggest GTP-binding proteins are involved in DSPC secretion and differentiation of fetal type II cells is accompanied by changes in GTP binding characteristics.

Animals↗
PubMed1992

Oxygen and the connective tissues.

Avascular connective tissues (cartilage, discs, cornea) change with maturation and aging, particularly in large animals, where diffusion paths are longest. It is suggested that the changes in such tissues are responses to increasing difficulties in obtaining oxygen. Two almost identical structural polymers are made in these tissues: chondroitin sulphate, which requires large amounts of oxygen for biosynthesis and keratan sulphate, which requires relatively little. The observed balance of these polymers in the tissue is proposed to depend on the control of biosynthesis by the ambient oxygen tension, and/or selective breakdown.

Animals↗
PubMed1992

Control of collagen fibril diameters in tissues.

It is proposed that radial growth of collagen fibrils, which takes place in all connective tissues to varying extents, according to the tensile stresses exerted on them, proceeds mainly by aggregation of protofibrils (approximately 10 nm) and existing fibrils. In young tissues, fibrils are prevented from making frequent intimate contacts which would lead to aggregation by abundant interfibrillar proteoglycan, that keeps the fibrils apart. Collagen fibrils are probably unable to fuse except when the molecules within them are packed in the same sense, i.e. fusing fibrils are parallel. The roughly equal numbers of parallel and antiparallel fibrils seen in several tissues must limit radial fibril growth in older tissues, where proteoglycan is usually less abundant. Possible origins of the balance of fibril polarities, which must be conserved after fibril nucleation on cell or non-cell templates, are analysed. The two controlling factors, ambient proteoglycan and fibril polarity, working against the tendency of fibrils to fuse, account for many features of the observed distributions of collagen fibril diameters in diverse tissues and at different ages.

Collagen↗
PubMed1992

The chemical morphology of the vitreous.

The water of the vitreous is stabilised by an ordered meshwork of very fine collagen fibrils that are tied together in loosely parallel bundles or sprays by bridges of sulphated glycosaminoglycan. Some fibril bundles run at right angles to other bundles. In these respects vitreous resembles a very dilute corneal stroma. The glycosaminoglycans of the vitreous (hyaluronan and chondroitin sulphate) aggregate with themselves and with each other in solution. The protein cores of the proteoglycans are attached to collagen fibrils. Thus, a three-component cross-linked structure is formed: collagen fibril-->proteoglycan protein core-->glycosaminoglycan chain-->glycosaminoglycan chain-->protein core-->collagen fibril. Hyaluronan can aggregate directly with chondroitin-6-sulphate, or with aggregated glycan cross-links, thus entering into an infinite meshwork.

Collagen↗