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Biomedical subjects

A Ross

Publications and source records attributed to A Ross.

At least 217 records · Page 12Linked to original sources
PubMed1984

Patterns of obstetric procedures use in maternity care.

The use of seven obstetric procedures was studied in two institutions that use different approaches to maternity care. The study population included 796 women delivering at Booth Maternity Center and 804 women with similar sociodemographic characteristics delivering at Thomas Jefferson University Hospital during 1977 and 1978. Several differences were found between the two institutions. The majority of selected procedures were used more often at Thomas Jefferson University Hospital than at Booth Maternity Center. The greatest differences were found for women at low intrapartum risk, while differences were smallest for women at high prenatal and intrapartum risk. The two institutions differed in their use of procedures for women at various levels of prenatal and intrapartum risk. The findings suggested that most of the differences did not reflect different levels of risk in the populations served, but were due to other unidentified factors.

Adult↗
PubMed1983

Determinants of transstenotic gradients observed during angioplasty: an experimental model.

Pressure gradient measurement across a stenosis is used during angioplasty to aid catheter positioning and estimate dilatation efficacy. The angioplasty catheter itself, however, further reduces lumen size, and therefore augments the transstenotic gradient. To more precisely define the catheter influence on gradient, we derived a theoretical expression relating the measured gradient with the angioplasty catheter in situ to the "true" gradient; that is, the gradient in the absence of the angioplasty catheter. We then tested this theoretical construct in a canine femoral artery angioplasty model. Fifty-four measurements were performed using 23 separate, 3-mm-long, 40 to 70% stenoses. As predicted by the theoretic model, "true" gradient is compounded by the angioplasty catheter principally as a function of the angioplasty catheter diameter (Dc) and the stenosis diameter (Ds). The best-fit curve of data points relating "true" and compounded gradients to various Dc and Ds combinations can be expressed as: Measured gradient = K X true gradient, where K = 0.25 (e)4.47 (Dc divided by Ds) and e = 2.718. Thus, the transstenotic gradient measured at angioplasty overestimates "true" resting gradient in a predictable manner, which is dependent on the ratio of Dc to Ds.

Angioplasty, Balloon↗
PubMed1982

[Demonstration of Chlamydia by means of vaginal cytology].

There are mostly metaplastic cells, which are affected by chlamydia, show a dense usually cyanophilic cytoplasm with vacuolization. They are characterized by more or less round granula, sometimes also amorphous inclusion bodies. The vacuoles are multiple and mostly perinuclear, sometimes the nucleus is pushed aside like a signet-ring cell. Also columnar cells of the endocervix may be infected by chlamydia. They are showing more less characteristic signs, mostly a fine vacuolated cytoplasm. A smear of the endocervix, wet fixed, stained by Papanicolaou, allows the suspected diagnosis "chlamydia-infection", if metaplastic or endocervical cells show these characteristic changes. The proof diagnosis however is only possible by cell-culture.

Bacteriological Techniques↗
PubMed1982

Intrauterine contraceptive devices in diabetic women.

11 of 30 (36.6%) insulin-dependent diabetic women fitted with intrauterine contraceptive devices (IUCDs) became pregnant within 1 year, whereas the pregnancy rate for non-diabetic women fitted with the same types of IUCD by the same consultant gynaecologists over a similar time period was 4 per 100 women years (4%). As soon as the high risk was recognised, devices were removed (2 from diabetic women who were pregnant and 19 from non-pregnant diabetic women), and patients were advised about other methods of contraception. The IUCDs were examined in a scanning electron microscope with X-ray microprobe analysis to measure the amount of copper eroded from the wire, the extent of the encrustation (if any) deposited on the wire, and the composition of the deposit, and the data were compared with those for 111 devices removed from non-diabetic women, 40% of the IUCDs from diabetic women had sulphur and chloride in the deposit, compared with 15.3% of IUCDs from normal women, and fewer IUCDs from diabetic women had calcareous deposits. In devices from normal women, erosion and deposition seemed to occur independently, but in IUCDs from diabetic women, there was high erosion, there were also large deposits, and where there was little deposit, the erosion was slight. 7 of 14 IUCDs taken from normal women who had become pregnant with an IUCD in situ had a high sulphur plus chloride deposit; none of these IUCDs had a predominantly calcareous deposit compared with 19.8% of the IUCDs from non-pregnant normal women. The evidence militates against the insertion of IUCDs in diabetic patients and indicated that, even in non-diabetic women, there may be small groups for whom the risk of becoming pregnant is very high.

Adult↗
PubMed1982

Voluntary control of cardiovascular reactions to demanding tasks.

Three groups of 10 normotensives participated in a study exploring voluntary control of cardiovascular reactions to cognitive tasks. Pulse transit time (TT), interbeat interval (IBI), skin conductance level, and respiratory variables were monitored throughout one introductory and four experimental sessions. The groups were matched on the basis of initial TT and IBI responses to the taxing arithmetic and reasoning tasks. During experimental sessions, one group (FB) was provided with visual analogue TT feedback, while the REL group was given detailed relaxation instructions. A third group (CON) performed the same sequence of tasks but was not instructed to modify cardiovascular reactions at any point. Training in voluntary control was carried out in resting (no-task) conditions, and during task administration. Both treatment groups showed lower cardiovascular reactions than controls in task trials. Only REL subjects lengthened TT in no-task conditions, while both FB and REL groups showed smaller cardiovascular reactions than CON during the tasks. Effects were confined to cardiovascular variables, since respiratory and electrodermal reactions during task administration were similar in all groups. The effects of treatments were especially marked among the most reactive subjects.

Adult↗
PubMed1982

The influence of hormonal therapy on survival of men with advanced prostatic cancer.

Although hormonal therapy has been used for almost 40 years in the management of patients with prostatic cancer there is no consensus on whether this treatment prolongs life in these men. In an attempt to answer this question survival of 65 control patients seen from 1937 to 1940 was compared to survival of patients who received hormonal therapy from 1942 to 1944. These intervals were selected in an attempt to minimize the influence of medical advances other than hormonal therapy. Although life table graphs indicated that survival was extended for patients who entered in the hormonal era our analyses indicate that the difference in survival between treatment and control groups can be accounted for by a trend toward lower mortality in patients who entered later in the study rather than by hormonal therapy. The temporal trend was noted in all major subgroups of patients. These data suggest that in this study hormonal therapy had little impact on the over-all survival of men with advanced prostatic cancer and that every effort must be made to explore new avenues for the treatment of these patients. In the future, hormonal therapy may be most effectively used when the poorly responsive patients can be identified at an earlier time in the disease and treated with alternate forms of therapy.

Adenocarcinoma↗
PubMed1982

A review of Burkitt's lymphoma. Importance of radiographic diagnosis.

Burkitt's lymphoma is a malignant proliferation of undifferentiated B lymphocytes that most often affects children. In endemic areas of Africa, the jaws are the sites most frequently involved. In non-endemic areas of North America, the jaws are involved in only 15-18 per cent of the cases. The oral and maxillofacial surgeon can play an important role in the early diagnosis of Burkitt's lymphoma by recognizing the clinical signs of multiple loose teeth and jaw tenderness coupled with the radiographic signs of generalized destruction of tooth crypts and diffuse disruption of jaw trabeculation. Successful treatment results from a combination of early diagnosis and controlled chemotherapy.

Adolescent↗
PubMed1982

Gastric tumorigenesis by a single dose of 4-(hydroxymethyl)benzenediazonium ion of Agaricus bisporus.

4-(Hydroxymethyl-benzenediazonium tetrafluoroborate was administered as a single intragastric instillation at 400 micrograms/g to Swiss albino mice. The treatment gave rise to glandular stomach tumours in incidences of 30% in females and 32% in males. Histopathologically, the tumours were classified as polypoid adenomas and adenocarcinomas. This diazonium ion is an ingredient of the cultivated mushroom of commerce, Agaricus bisporus. The implications are self-evident.

Adenocarcinoma↗
PubMed1982

Motor functions: associated primitive reflex profiles.

The results of reflex/motor activity interactions in 177 normal infants are evaluated. The asymmetrical tonic neck reflex, tonic labyrinthine reflex-supine, and Moro reflexes were assessed for each child at birth and at intervals up to 12 months. Ages of rolling prone to supine, rolling supine to prone, and sitting alone were elicited from parents. The effects of the primitive reflexes on early motor activity were assessed, and statistically significant correlations were demonstrated between decreased reflex activity and the emergence of motor milestones. The distinctive association of reflex activity with motor function suggests the interaction of several reflexes (a primitive reflex profile) rather than the influence of isolated reflex activity. Such patterns support the hypothesis that decreasing primitive reflex activity is associated with the onset of volitional motor activity in normal infants.

Developmental Disabilities↗
PubMed1982

Essential hypertension and psychological functioning: a study of factory workers.

This study was designed to examine the links between psychological characteristics and mild essential hypertension. Hypertensives were identified through mass screening of industrial populations. Sixteen men under the age of 56 whose blood pressure remained above 145/90 (145/95 for the 45-55 age group) on three separate occasions were compared with 13 age-matched normotensives from the same population. Participants completed a series of personality questionnaires, and carried out concurrent mood ratings and blood pressure self-monitoring four times daily for 14 days. Subjects remained unaware of their diagnostic status until the procedure was completed. No differences between groups were found on measures of trait anxiety, total hostility or direction of hostility. State anxiety and Type A (coronary-prone) scores were significantly higher in normotensives than in hypertensives. Analysis of mood and self-monitored blood pressure revealed consistent correlations between negative mood and higher pressure in both groups. Comparison of correlations between blood pressure, tension and anger with the correlations of pressure with a control mood scale permitted spurious associations based on expectancies or reporting biases to be distinguished from genuine effects. Only the correlation between tension and systolic pressure in the hypertensive group exceeded the correlation with the control mood scale. Self-monitored pressure also correlated with pressure levels recorded in the laboratory. These results suggest that examination of blood pressure variations and psychological factors on a longitudinal basis may be valuable, particularly in the development of self-management procedures for essential hypertensives.

Adaptation, Psychological↗
PubMed1981

Cellular basis for the loss of carcinogen from methylcholanthrene-impregnated Millipore membrane.

Millipore 'discs' impregnated with methylcholanthrene dissolved in wax or in crystalline form implanted subcutaneously in mice evoke an early intense macrophage and giant cell reaction; later the discs become covered with connective tissue, and eventually fibrosarcomas develop in their vicinity. Studies with tritium-labelled material show that under these conditions methylcholanthrene (MC) is removed from the discs and broken down rapidly (half life about 7 days) to a water-soluble product, which diffuses locally, is distributed widely via the blood stream, and is excreted in faeces and urine. Removal of label is halted by whole-body irradiation (550 R) with the disc area shielded; this observation, in conjunction with the histological and autoradiographic findings and the paucity of label in cells stripped from excised discs, points to the conclusion that the removal of MC from impregnated discs, and its subsequent degradation, depend on the presence of macrophages and the continual replacement of spent macrophages by new cells generated centrally. The rate of disappearance of label from implanted [3H]MC discs was not altered by administration of Corynebacterium parvum; this, however, does not exclude the possibility that the metabolic pathways involved in the removal of MC are altered. To investigate this it is proposed to study, in both normal mice and mice treated with C. parvum, the extent to which cytochrome P450 and other enzymes concerned in the activation and detoxification of polycyclic hydrocarbons by liver microsomal fractions are inducible in the macrophages that accumulate in inflammatory exudates. This histological techniques used should be readily applicable to the study of the early stages of chemical carcinogenesis and the host reaction to transformed cells.

Animals↗
PubMed1981

Protein-depleted chromosomes. I. Structure of isolated protein-depleted chromosomes.

Protein-depleted isolated Chinese hamster chromosomes have been obtained by different protein extraction procedures and examined by electron microscopy and SDS-polyacrylamide gel electrophoresis. Salt-resistant centromeric and telomeric structures are visible in protein-depleted chromosomes and the protein-depleted chromosomes appear to have a regular, longitudinal pattern in critical point dried preparations. The scaffold-like structure of protein-depleted chromosomes is highly affected by the ionic strength and composition of the extraction medium and by the spreading conditions. Nucleosomal histones of isolated chromosomes proved to be more sensitive to the sodium chloride treatment than histones of isolated chromatin. A small, but constant quantity of core histones was detected in 2 M salt extracted chromosomes and H3 and H4 histones of isolated chromosomes appeared to be resistant to the sodium deoxycholate treatment.

Animals↗