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Biomedical subjects

O Hall

Publications and source records attributed to O Hall.

At least 19 recordsLinked to original sources
PubMed1993

The value of histoquantitative measurements in prognostic assessment of renal adenocarcinoma.

In a series of 135 patients with renal-cell carcinomas (followed up for a mean of 9.5 years), a variety of clinical and histological factors were analyzed in relation to morphometric measurements of the nuclear parameters in the primary tumours to establish their value as prognostic factors. Clinical, histological and morphometric factors were significantly interrelated in that the metastatic high-grade tumours had larger nuclei, larger variation in nuclear size and shape, and were also rapidly proliferating. In a univariate analysis, the most important clinical predictor of recurrence-free survival (RFS) was T category, followed by combined nuclear grade, N category, nuclear grade, tumour size, sex and M category. The most important quantitative predictor of RFS was the mean area of the 10 largest nuclei (NA10), the mean of the longest nuclear axis (Dmax), SD of nuclear area (SDNA), the volume-corrected mitotic index (M/V index), inflammatory-cell reaction, SD of nuclear perimetry (SDPE), and the mean of nuclear area (NA). M category, T category, combined nuclear grade, nuclear grade and N category were significantly related to patient survival. Of the quantitative variables, M/V index, Dmax and NA were significant predictors of survival in a univariate analysis. Females had longer RFS than men, and density of tumour-infiltrating lymphocytes (TIL) referred to an increased risk of recurrent tumour in both sexes. In a multivariate analysis, the RFS was independently predicted by the clinical stage, female sex and mitotic frequency/mm2, while nuclear parameters or nuclear grading had no independent prognostic value. The extent of the primary tumour was the single most important determinant of survival, followed by the proliferation rate of the tumour. In local T1-2NOMO tumours, mitotic frequency/mm2 was the only independent prognostic factor for RFS. The clinical stage, mitotic frequency/mm2, nuclear grade and density of TIL were independent predictors in Cox's analysis. In these local tumours, mitotic frequency/mm2 of neoplastic epithelium was the only independent prognostic factor. The results indicate that although an accurate prognostic evaluation of renal-cell carcinomas can be based on subjective nuclear grading and histoquantitative measurements of nuclear parameters, the simple assessment of mitotic frequency alone supplies most of the prognostic data, particularly in local tumours.

Adult↗
PubMed1986

Using social indicators to locate mental health facilities.

The following article reports the results of a process designed to improve the accessibility of psychiatric inpatient services by identifying sites which are closest to the greater number of people in need. Facility locations and catchment areas for a test region are noted along with facility sites arrived at by a more conventional approach. The estimated travel time was 11 percent lower in the test methodology. This finding indicates that major improvements in the reduction of travel time are possible when quantitative techniques are applied by mental health planners.

Adolescent↗
PubMed1978

Adrenal-regeneration hypertension in Wistar-Furth rats.

The susceptibility of young virgin female Wistar-Furth (W/Fu) rats to adrenal-regeneration hypertension (ARH) was evaluated by comparing the blood pressure of adrenal-enucleated, mononephroadrenalectomized, salt-loaded rats with that of similarly treated rats having one intact adrenal over a period of 5 weeks. Hypertension began to appear in animals of the first group by the 3rd week, affected all of them by the 4th week, and increased in severity during the 5th week. Control rats remained normotensive during the study. Hypertensive rats developed marked enlargement of the heart and kidney, which frequently displaced myocardial scarring and nephrosclerosis, respectively. These studies do not support the contention that W/Fu rats display heightened resistance to ARH to which, in fact, they appear to be just as susceptible as are most other strains.

Adrenal Glands↗
PubMed1978

Experimental hypertension and other responses to 18-hydroxy-deoxycorticosterone treatment in the rat.

Young female unilaterally nephrectomized, salt-loaded, Sprague-Dawley rats were treated with 200 microgram or 1 mg 18-hydroxy-deoxycorticosterone-21-acetate (18-OH-DOCA) in oil daily, and a group of kidney-intact animals on a normal salt intake was given 2 mg/day. The hormone was not found to increase saline consumption, increase urinary potassium or kallikrein excretion, or depress serum renin activity or potassium concentration. Slight hypertension did develop at 3 weeks in salt-loaded rats on the lowest dose, but this was neither increased by higher dosage or longer treatment, nor reflected by increased heart or kidney weight. The effect of 40-mg pellet implantation of DOCA and 18-OH-DOCA was then compared in unilaterally nephrectomized, salt-loaded, female Fischer 344 rats. The former caused increased saline consumption, hypertension, hypokalemia, and heart and kidney enlargement, whereas 18-OH-DOCA did not. Thus, the hypertensogenic potency of 18-OH-DOCA is, at best, a reflection of its known, very weak, mineralocorticoid activity.

18-Hydroxydesoxycorticosterone↗
PubMed1976

Delayed onset and reduced severity of adrenal-compression hypertension in rats treated with digitoxin.

1. Bilateral compression of adrenal glands combined with unilateral nephrectomy and followed by imposition of a high sodium chloride intake caused severe hypertension in all rats, accompanied by enlargement of the heart, kidneys and adrenal glands, atrophy of the thymus and severe nephrosclerosis. 2. Digitoxin treatment delayed the onset, reduced the incidence and ameliorated the magnitude of the hypertensive response in such rats; it also reduced the degree of cardiac hypertrophy, the severity of nephrosclerosis and completely prevented enlargement of the adrenals and kidneys or atrophy of the thymus.

Adrenal Glands↗
PubMed1975

Excretion of Na and H2 O and hypertension after adrenal enucleation or compression.

An attempt was made to analyze the participation of the several independent variables that must contribute to the reproted inability of large male adrenal-enucleate rats withintact kidneys to normally excrete sodium following a light oral sodium load. This was prompted by a desire to understand whether the phenomenon was improtant to development of adrenal-regeneration hypertension (ARH). The results indicated that sdoium retention required the presence of both kidneys as it was not evident in unilaterally nephrectomized rats. The failure of ARH to develop in rats having both kidneys argues against a cause-and-effect relationship between the two phenomena. Sex does not appear to be important to sodium retention. Various fasting periods were employed, but with none of them did rats with a single kidney exhibit sodium retention. Since the conditions necessary to elicit imparied sodium excretion are incompatible with the induction of ARH and those essential to development of ARH prevent significant sodium retention, the two must be considered as independent manifestations of distrubed glandular function.

Adrenal Medulla↗
PubMed1975

Evolution of adrenal-regeneration hypertension in blinded rats.

The influence of blinding upon the blood pressure and adrenal regeneration of monoephrectomized but otherwise normal and mononephrectomized adrenal-enucleate rats on a high Na intake was evaluated. Blinding had no effect on control blood pressure, or upon the incidence, course and severity of adrenal-regeneration hypertension. Similarly there was no discernible effect on the regeneration of enucleate adrenal glands. The adrenal glandsands of otherwise normal blinded rats showed some enlargement in proportion to body weight, a finding which is probably attributable to loss of body weight in several animals.

Adrenal Medulla↗
PubMed1975

Genetic influence on saline consumption and salt hypertension as exhibited by the response of various rat strains and sub-strains.

Female rats of 2 Sprague-Dawley sub-strains and of the Wistar and Fischer 344 strains were sensitized to the hypertensogenic effect of excess salt by removal of 1 kidney and by being given 1% NaCl solution as their sole drinking fluid. One of the Sprague-Dawley sub-strains (SPD) and the Wistar (CFEP) rats developed progressive saline polydipsia of equivalent degree, blood pressure rose, and about half of the members became hypertensive during treatment. Rats of the other Sprague-Dawley strain (CFNP) also showed a progressive saline intake; but although they drank substantially less saline, the incidence of hypertension among them was increased by 50%. Animals of the Fischer 344 strain displayed neither saline polydipsia--the intake remaining relatively constant at a very low level throughout the experiment--nor hypertension. Salt hypertension appears to be affected by genetic factors in at least 2 ways, one of which regulates the quantity of salt ingested (salt appetite), while the other controls the susceptibility to salt excess or perhaps to hypertension per se. Fischer 344 rats have the ability to restrict the volume consumption of saline; their resistance to enforced high salt intake has yet to be established.

Animals↗
PubMed1975

Hypertension from compression and/or enucleation of the adrenal glands in the rat.

Previos studies have shown that compression of the adrenal glands is as effective as adrenal enucleation in causing hypertension in rats. Unilateral adrenal enucleation is ineffective, however, if a normal contralateral adrenal gland is present. The studies reported herein demonstrate that unilateral compression also fails to cause hypertension in the presence of a normal contralateral gland. When present singly, either enucleate or compressed adrenals cause hypertension; when either is present with a normal contralateral gland, the blood pressure is unaffected. When compressed or enucleate glands constitute the pair, in any combination, hypertension ensues. However, whereas an enucleate gland remains extremely atrophic in the presence of a normal gland, compressed glands attain a much larger size under this circumstance. Furthermore, a compressed gland is less inhibitory to the regeneration of a contralateral enucleate gland than is a normal adrenal. Whereas enucleate glands, whether bilateral or unilateral, are always smaller than normal glands, compressed adrenals may be enlarged. The hypertensogenic function of compressed adrenals is, like that of enucleate glands, suppressed by the presence of a normal gland. The growth response of compressed or enucleate glands, whether bilateral or single, appears to depend upon the degree of injury inflicted upon them. There is a considerable discrepancy in the size of individual members of a pair when one or both have been injured, that members of a normal pair do not exhibit.

Adrenal Glands↗