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Biomedical subjects

J Newman

Publications and source records attributed to J Newman.

At least 253 records · Page 14Linked to original sources
PubMed1982

Urothelial abnormalities in the obstructed bladder.

Bladder mucosa from patients undergoing prostatectomy was examined histologically for evidence of pre-malignant change. The mucosal appearances were compared with tissue taken from control patients without bladder outlet obstruction. The appearances in patients with uncomplicated obstruction and in control patients were found to be similar and dysplastic change was uncommon. However, dysplasia was found relatively frequently in patients with bladder outlet obstruction complicated by the presence of infection, catheters or stones. In all, 10 out of 74 patients were found to have dysplasia and 7 of these agreed to have a further cystoscopy and biopsy taken at an interval of between 10 and 28 months after the first examination. Persistent dysplasia was found in all 7 cases and in 3 of these it had progressed from mild to moderate in severity. The significance of these findings is discussed.

Adult↗
PubMed1981

Partial purification of biologically active, low molecular weight, human antihemophilic factor free of Von Willebrand factor. I. Partial characterization and evidence for disulfide bond(s) susceptible to limited reduction.

Partially purified (approx. 5000-fold), low molecular weight human antihemophilic factor, free of detectable Von Willebrand factor (ristocetin cofactor activity or Von Willebrand antigen), was prepared from fresh citrated plasma by limited reduction with 1 mM dithiothreitol and chromatography on Sepharose CL-4B, Sephadex G-100, and polyelectrolyte E-5. The ratio of antihemophilic factor activity to Von Willebrand factor activity or antigen was greater than 27 000 : 1. The antihemophilic factor activity could be neutralized with homologous antibody and could be further increased with thrombin. The Mr (approx. 116 000) was determined by calibrated gel permeation chromatography, electrophoresis in 5% polyacrylamide gels with sodium dodecyl sulfate and by electrophoresis in large-pore acrylamide gels without it. Since the low Mr antihemophilic factor could be prepared by treating fresh rather than fresh-frozen plasma with dithiothreitol, it was concluded that partial reduction of the antihemophilic factor with this reagent helped to maintain the antihemophilic factor in a low Mr form. When iodo[l-14C]acetamide was used to alkylate the reduced plasma proteins prior to purification, the molecular weight of the purified antihemophilic factor remained low despite numerous purification steps. By this means, one of four radioactive proteins (Mr 116 000) in the final preparation was bound specifically to homologous antihemophilic factor antibody and attributed to 14C-labeled antihemophilic factor. While the data suggest that antihemophilic factor in fresh plasma contains one or more dithiothreitol-sensitive intramolecular disulfide bonds, the possibility of disulfide linkages with other proteins(s) cannot be excluded.

Chemical Phenomena↗
PubMed1981

Evidence for orbital deformation that may contribute to monocular blindness following minor frontal head trauma.

Traction injury to the optic nerve and vasa nervorum is the suggested etiology for monocular blindness following trivial frontal trauma. Holographic interferometry was used on human skulls to demonstrate orbital deformation in response to nondestructive frontal loading. The findings suggest an additional mechanism for energy dissipation and therefore for optic nerve injury following frontal impact.

Blindness↗
PubMed1981

Intermittent exotropia: is surgery necessary?

Sixty cases of intermittent exotropia were studied to compare the outcome of those patients treated medically with the outcome of those patients treated surgically. Below 30 prism diopters of intermittent exotropia, there is a high functional cure rate in both groups. Preoperative orthoptics did not lead to a surgical overcorrection. And finally, central fusion is not essential for a clinical cure.

Adolescent↗
PubMed1981

Surface ultrastructure of the epithelia lining the normal human lower urinary tract.

The finding of cells with pleomorphic microvilli in urinary sediments has been proposed as an indicator for urothelial neoplasia. Recently, in addition to such cells, others with less bizarre, non-pleomorphic microvilli have also been found in urothelial cancers, and these cells are similar in appearance to others detected in the urinary sediments of healthy people. When using scanning electron microscopy as a diagnostic tool, these cells are a possible source of confusion. The entire lower urinary tracts from people free of urothelial neoplasia have therefore been examined to delineate the normal surface appearance of all cell types which could appear in the urine. There are 4 predominant cell types: the large, flat squamous cells of the urethral meatus which have abundant microridges; cells with mucus-coated, short, stubby microvilli lining the urethra and renal papilla; immature urothelial cells with chains and ridges of bleb-like processes in the ureters and bladder; and, also in the ureters and bladder, mature urothelial cells with microridges or ruffles. The lining epithelia of the normal urethra and renal papilla may thus contribute cells with non-pleomorphic stubby microvilli to urine sediments, which cannot be differentiated by scanning electron microscopy alone from similar cells derived from urothelial neoplasms. However, the normal complement of cells lining the adult lower urinary tract does not include any with prolific, long, pleomorphic microvilli such as characterize transitional-cell carcinomas of the urothelium.

Adolescent↗
PubMed1981

Intestinal parasites in Southeast Asian refugees.

A survey of intestinal parasitism in 6,241 Southeast Asian refugees (3,576 males and 2,665 females) indicated that 32.9 percent of the refugees had one or more intestinal parasites. A total of 1,178 (57.3 percent) males and 878 (42.7 percent) females harbored the parasites, with helminths representing the most frequent isolate. Intestinal parasitic infections may be considered minimal public health threats in the United States because of effective hygienic practices and sanitation facilities. However, it is important to emphasize that the attack rate also will be influenced by continued health education, job activities, and diagnosis and treatment of the refugees for these parasites.

Adolescent↗
PubMed1981

Diffuse neoplastic change in urothelium from tumour-bearing human lower urinary tract.

In nine patients, who underwent radical cystectomy for transitional cell carcinoma of the bladder, detailed maps were prepared of results of the light microscopic findings and of the surface features of the urothelium as observed by scanning electron microscopy. Scanning electron microscopy revealed a more widespread distribution of residual neoplastic disease than suspected by light microscopy alone. This observation is based on the presence of abnormal cells carrying pleomorphic microvilli in association with other cells infrequently seen in normal healthy urothelium. Such changes have been directly related to neoplastic transformation in numerous experimental studies and have also been observed in human transitional cell carcinoma. This widespread distribution of these markers for neoplastic transformation explains the multiple recurrences of transitional cell carcinoma which characterises neoplastic disease of the bladder.

Adult↗
PubMed1980

Dynamic light-scattering evidence for the flexibility of native muscle thin filaments.

We have obtained clear evidence for the flexibility of native scallop adductor thin filaments by studying the temperature and ionic strength dependence of the average decay constants obtained from intensity fluctuation spectroscopic (IFS) measurements. The low-angle (10-25 degrees ), average decay constants obtained from time autocorrelation functions of scattered light were independent of concentration (0.08-1.3 mg/ml), scaled with the ratio of temperature to solvent viscosity, T/eta, over a range of 4-45 degrees C, and yielded a value for the translational diffusion coefficient of D(T) (5 degrees C) = (1.24 +/- 0.06) x 10(-8) cm(2)/s. From this value and the Broersma relation for rigid rods, we find an average filament length of 1.06 +/- 0.06 mum. Quantitative sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that at high temperatures (> 35 degrees C) or in 0.6 M NaCl, tropomyosin completely dissociates from native thin filaments. Decay constants from high-angle (60-150 degrees C) IFS temperature dependence measurements do not scale with T/eta and hence do not show the temperature dependence expected for rigid rods. The differences are not due to any change in length distribution of filaments with temperature or to the free tropomyosin in solution, but are attributed to nonrigid motions of the filaments. Similar experiments on samples in high- and low-salt solvents gave results consistent with this interpretation.

Actins↗
PubMed1980

Developing competence in problem solving. A behavioral model.

Problem solving is an integral part of effective physical therapy practice. A model depicting the behaviors of the problem solver while solving problems is presented. The behaviors are related to each step in the problem-solving process and to cognitive, affective, and psychomotor functions of individuals. Guidelines for using the model in didactic and clinical activities are presented.

Humans↗
PubMed1980

Reliability of the health hazard appraisal.

As part of a controlled clinical trial of Health Hazard Appraisal's (HHA) efficacy in stimulating risk reduction, the reliability of the HHA questionnaire was evaluated. Of 203 subjects, only 30 (15%) had no contradictions when comparing the responses of the follow-up with baseline questionnaire. Overall, there was an average of 1.6 contradictions per subject. Failure to control for reliability may account for apparent reduction of risk reported in previous studies of HHA.

Adult↗
PubMed1980

The feature-positive effect in adult human subjects.

Previous experiments with animals and young children have shown that discriminations based on the presence versus absence of a single feature are learned more easily when the feature appears on reinforced rather than nonreinforced displays. Six experiments demonstrated an analogous effect in college students, across a range of stimulus materials, general procedures, kinds of feedback, pacing of trials, and instructions to the subject. The results were analyzed in terms of the exceptionally strong control of behavior by events that are present on positive trials. These findings have implications for theoretical interpretations of human concept learning and decision making, and offer additional examples of the difficulty organisms experience in using "nonoccurrence" as a cue.

Concept Formation↗
PubMed1979

Structural and compositional changes associated with chlorine inactivation of polioviruses.

Chlorine inactivation of polioviruses resulted in the loss of viral ribonucleic acid, converting the viruses from 156S particles to 80S particles. However, it was found that virus inactivation occurred before the ribonucleic acid was released from the virions. Extraction of ribonucleic acid from partially inactivated virus suspensions indicated that chlorine inactivation was due to degradation of the ribonucleic acid before release and that ribonucleic acid loss was a secondary event. The empty 80S capsids had the same isoelectric point and ability to attach to host cells as infective virions. Thus, no major capsid conformational changes occurred during chlorine inactivation.

Capsid↗
PubMed1979

Hormone replacement therapy in the menopause: a suitable animal model.

Female CBA mice, aged 11 months, were treated cyclically with oral ethynyl oestradiol or oestrone sulphate for 3 months. The ovaries of all animals appeared to be atrophied. Target tissues throughout the genital tract showed a response to both oestrogens. Electron microscopy of both the endometrium and the urothelium demonstrated morphological changes characteristic of increased cellular metabolic activity in the treated mice. Endometrial hyperplasia developed in both treatment groups but more pronounced epithelial changes occurred with oestrone sulphate. This hyperplasia was accompanied by a doubling in the number of uterine cytoplasmic oestrogen receptors. A 50% fall in serum levels of luteinizing hormone in the treated mice revealed that the hypothalamic-pituitary system was still intact. Both oestrogens improved skeletal balance by changes in cortical-endosteal bone remodelling. The results suggest that the CBA strain of mouse is a suitable model for the study of the human climacteric and its response to hormone replacement therapy.

Animals↗
PubMed1978

Circulating thrombin time anticoagulant in a procainamide-induced syndrome.

Circulating anticoagulants are unusual in drug-induced syndromes. We evaluated the prolonged thrombin time of plasma from a patient with a procainamide-induced syndrome. This defect was shown to be due to a circulating anticoagulant that was not of fibrin or fibrinogen origin and that prolonged thrombin and reptilase clotting times of plasma. Subclinical doses of heparin sodium induced hemorrhagic manifestations in this patient. Following cessation of heparin therapy, the circulating anticoagulant persisted but the bleeding tendency abated. All clinical and laboratory manifestations of this syndrome abated gradually following cessation of procainamide therapy.

Aged↗