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Biomedical subjects

G Hill

Publications and source records attributed to G Hill.

At least 73 records · Page 4Linked to original sources
PubMed1996

Calcification in colorectal hepatic metastases correlates with longer survival.

BACKGROUND: Calcification occurs in 12-27% of hepatic colorectal metastases, but its clinical significance and its influence on prognosis are unknown. METHODS: All patients diagnosed with colorectal liver metastases at the Ottawa Regional Cancer Center in 1991 (n = 97), as well as those enrolled in chemotherapy trials in 1990-1992 (n = 51), were entered into a retrospective cohort study. Thirty-six patients were excluded due to inadequate follow-up. In the remaining 112, abdominal CT scans and/or ultrasound examinations were used to determine the presence of calcification. Charts were reviewed for variables, including primary tumour pathology, amount of liver involvement by tumour (< 25%, 25-50%, > 50%), and the chemotherapeutic agents received, and were subjected to multivariate and regression analysis. End point was survival in months or to December 1993 (median follow up 24 months). RESULTS: Patients with calcification (n = 31) (28%) were compared to those who did not have calcifications (n = 81). The groups were comparable with respect to sex, age, time to calcification, time to metastases, and treatment type. Calcification occurred independent of the degree of tumour differentiation, the presence of mucinous adenocarcinoma, or the hepatic tumour burden. Nine patients with calcified metastases (30%) had calcification at presentation. Biopsies showed calcification next to viable tumour cells with an absence of an inflammatory reaction. Survival was improved with better primary tumour differentiation and less tumour burden. The presence of calcification had a statistically highly significant improvement in survival (P < 10(-6), relative risk = .19) independent of other variables. CONCLUSIONS: The presence of calcification within a colorectal liver metastasis appears to imply a significantly better prognosis.

Aged↗
PubMed1996

Histopathologic characterization of hereditary benign prostatic hyperplasia.

OBJECTIVES: Recent studies suggest the presence of a hereditary form of benign prostatic hyperplasia (H-BPH). This study was undertaken to characterize the histopathologic features of BPH in these men. METHODS: Because study subjects with H-BPH were young (mean age 59 years) and had a large prostate (mean prostate weight 61 g), we compared the histopathologic findings in these men with those in two different control groups: (1) age-matched control subjects (mean age 59 years; mean prostate weight 31 g), and (2) prostate weight-matched control subjects (mean age 70 years; mean prostate weight 61 g). Using a color video image analysis system, we morphometrically determined stromal/epithelial ratios in histologic sections taken from 12 men with H-BPH, 36 age-matched control subjects, and 36 prostate weight-matched control subjects. RESULTS: The stromal/epithelial ratio was 2.6 +/- 1.4 in the men with H-BPH, 2.7 +/- 1.7 in the age-matched control subjects, and 1.7 +/- 0.9 in the prostate weight-matched control subjects. Regression analysis, which controlled for the differences in prostate weight or patient age between men with H-BPH and age-matched and prostate weight-matched control subjects, respectively, revealed a significant difference between men with H-BPH and prostate weight-matched control subjects (P = 0.015) but no difference from age-matched control subjects (P = 0.36). CONCLUSIONS: The larger prostates in young men with H-BPH are characterized by a higher stromal/epithelial ratio than are similar-sized prostates in older men with sporadic BPH. This finding gives rise to speculation that H-BPH is associated with an increase in stromal elements.

Adult↗
PubMed1996

Optimal cut-points when screening for more than one disease state: an example from the Canadian Study of Health and Aging.

A method is described for choosing optimal cut-points in screening test with a continuous score in order to divide people into any number of disease categories. The cut-points are chosen to minimize the overall expected loss, given a matrix of losses incurred by misclassifications. It is shown that the optimal cut-points depend on the column differences of the loss matrix. The effect of changing the loss matrix is examined. For the error counting matrix, where misclassifications are given equal weight, it is shown that the relationship between the minimal loss cut-point and the receiver operating characteristic (ROC) curve for two disease categories extends to the general case. The results of a study in which elderly people were screened for cognitive impairment and dementia are used to illustrate the method.

Aged↗
PubMed1996

Dementia among seniors.

The prevalence of dementia increases sharply in old age and is higher among women than men. Alzheimer's disease, the most common form of dementia, affects a greater proportion of women. On average, the number of years lived with dementia is longer for women, and women with dementia are more likely to be living in institutions than men with the condition.

Age Distribution↗
PubMed1995

In rat pinealocytes the cyclic GMP response to NO is regulated by Ca2+ and protein kinase C.

There is ample evidence that beta-adrenergic stimulation of cyclic GMP formation is potentiated by alpha1-adrenergic mechanisms, the latter leading to elevation of intracellular Ca2+ concentration ([Ca2+]i) and protein kinase C (PKC) activation. Recent studies have shown that nitric oxide synthase (NOS) and nitric oxide (NO) are a component of the adrenoceptor-cyclic GMP signalling pathway. The aim of the present investigation was to study the roles of alpha1-adrenergic mechanisms, Ca2+ and PKC on NO-stimulated cyclic GMP formation. To this end suspension cultures of rat pinealocytes were treated with the NO donor sodium nitroprusside (SNP) in the presence of alpha1-adrenergic agonists, [Ca2+]i-elevating substances, PKC inhibitors, followed by measurement of cyclic GMP accumulation. It was found that alpha1-adrenergic stimulation did not affect NO-activated cyclic GMP synthesis. Therefore alpha1-mechanisms act prior to NO induction of cyclic GMP. Agents, which elevate [Ca2+]i depressed NO-induced cyclic GMP formation. Since literature data show that Ca2+ stimulates pineal NO formation it is apparent that Ca2+ has antagonistic effects in the pineal adrenoceptor-cyclic GMP signalling pathway. The inhibitory effect of Ca2+ was unchanged after inhibition of phosphodiesterases suggesting that it may interfere with cytosolic guanylyl cyclase activation. Inhibition of PKC, but not of other protein kinases, decreased NO-activated cyclic GMP formation. Therefore it appears that non-alpha1-adrenergic-regulated PKC possesses a regulatory rote in NO-induced cyclic GMP formation.

Animals↗
PubMed1995

Conversion from 2.5 mg to 1.25 mg indapamide in patients with mild to moderate hypertension.

BACKGROUND: Indapamide is an effective antihypertensive drug with diuretic and vasodilating activities. The common starting dose has been 2.5 mg to 5 mg. A lower dose formulation (1.25 mg) is now available. The safety and efficacy of switching patients from indapamide 2.5 mg to indapamide 1.25 mg was evaluated in this randomized, double-blind, multicenter clinical trial. METHODS: Three hundred seventy-eight adult patients with mild to moderate essential hypertension were enrolled in a washout period, during which patients received single-blind placebo for 4 weeks. All 378 patients qualified for the study and received open-label treatment with indapamide 2.5 mg for 8 weeks. Of the 378 patients, 265 responded to indapamide 2.5 mg and were randomized to receive double-blind treatment with either indapamide 1.25 mg (n = 132) or 2.5 mg (n = 133) for 8 weeks. Overall, 245 of the 378 patients who were initially enrolled completed the study. The primary efficacy variable was the number of patients in each treatment group who maintained a supine diastolic blood pressure of < or = 90 mm Hg (treatment success) by the end of the double-blind period (week 16). RESULTS: Treatment with indapamide 1.25 mg once daily was as efficacious as the 2.5-mg once-daily dose. No significant difference was observed for the percentage of patients who achieved treatment success between the patients switched from indapamide 2.5 to 1.25 mg (74%) and the control group maintained on indapamide 2.5 mg (70%). The incidence of drug-related adverse events during the double-blind period was similar between the two treatment groups. The mean change from pretreatment baseline to endpoint in serum potassium was -0.2 mEq/L (-0.2 mmol/L) in the indapamide 1.25 mg treatment group, compared with -0.4 mEq/L (-0.4 mmol/L) in the indapamide 2.5 mg treatment group. CONCLUSIONS: Indapamide 1.25 mg given once daily for 8 weeks was as effective as 2.5 mg once daily in reducing systolic and diastolic blood pressure in patients with mild to moderate hypertension.

Adult↗