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Biomedical subjects

H Ross

Publications and source records attributed to H Ross.

At least 55 records · Page 3Linked to original sources
PubMed1997

Indirect calorimetry, body composition and small bowel function in asymptomatic HIV-seropositive women.

Extrapolation of data from energy balance studies in HIV-seropositive men to HIV-seropositive women may be inaccurate due to gender differences in body composition, hormones and metabolism. If women have a different metabolic response to the human immunodeficiency virus (HIV), nutritional advice may differ from HIV-seropositive men. Ten asymptomatic HIV-seropositive women were matched with 10 heterosexual female controls from low-risk groups. Subjects and controls had assessment of energy and protein intake, resting energy expenditure (REE) and substrate oxidation, small bowel absorption and permeability and body composition. There were no significant differences in REE, substrate oxidation and body composition. Energy and protein intake and small bowel permeability were increased and sugar absorption decreased in HIV-seropositive women (all P < 0.05). Unlike asymptomatic HIV-seropositive men, asymptomatic HIV-seropositive women do not have significant alterations in metabolism or body composition. Therefore, nutritional advice may need to vary according to the gender of the asymptomatic HIV-seropositive subject.

Adult↗
PubMed1997

Life-time problem drinking and psychiatric co-morbidity among Ontario women.

Women problem drinkers in the community, aged 15-64 years, with and without life-time psychiatric co-morbidity were compared to examine the association of this co-morbidity with alcohol consumption patterns, course and chronicity of problem drinking, treatment service utilization and other substance use and misuse. The women problem drinkers were also compared with non-problem drinkers on substance use patterns and utilization of services. The study employs data from the Mental Health Supplement to the Ontario Health Survey, a province-wide household population study. The University of Michigan Composite International Diagnostic Interview (UM-CIDI) was administered by trained lay interviewers and subsequently World Health Organization computer algorithms were used to generate DSM-III-R diagnoses based on the interview responses. Multiple logistic regression analysis indicated that psychiatric co-morbidity was associated with less education, earlier onset of problem drinking and one indicator of binge drinking. Co-morbidity also greatly increased the chances of women problem drinkers having sought mental health treatment. Women problem drinkers were significantly younger (about 7 years) than women in the general population, perhaps an indicator of an increased mortality rate.

Adolescent↗
PubMed1997

Importance of decreased heart rate in predicting transplant coronary artery disease.

Studies in animals and humans have demonstrated that an increased heart rate is a predictor for the development of coronary atherosclerosis and overall cardiovascular mortality. In contrast, we have previously reported that the need for pacemaker implantation because of bradycardia in heart transplant recipients is associated with an increased prevalence of transplant coronary artery disease (TxCAD). Hence, the relevance of changes in heart rate to the development of TxCAD remains unclear. Intra-coronary ultrasound examinations (ICUS) were therefore analyzed in 130 heart transplant recipients (age 50 +/- 11 yr) studied at annual evaluations (3.7 +/- 3.0 yr after transplantation). Quantitative ultrasound measurements were obtained by calculating mean coronary artery intimal thickness (MIT) obtained by examination of the left anterior descending artery. The presence of TxCAD was defined as MIT > 0.3 mm. Resting heart rates (HR) were recorded with the patients in the supine position during routine echocardiography. Based on HR recordings, two groups were defined: group 1, HR below; or group 2, HR above the median. TxCAD was detected in 40% of the ICUS studies overall. The prevalence of TxCAD was higher in group 1 (49%) compared with group 2 (33%), p < 0.05. There was no significant difference in donor ischemic time or donor gender, recipient age, gender, body weight, CMV status, creatinine, total cholesterol, use of lipid lowering drugs or diltiazem. Donor age and use of beta-blockers were higher in group 1 compared with group 2 (29 +/- 10 vs. 25 +/- 9 yr, and 15% vs. 5%, for donor age and beta-blocker use, respectively). By multivariate regression analysis only donor age and years after transplantation were independently correlated with TxCAD. After excluding patients taking beta-blockers and diltiazem, the prevalence of CAD was still higher in group 1 (50%) vs. group 2 (34%). In conclusion, transplant coronary artery disease is more prevalent in patients with lower, rather than higher, heart rates. The reason for this is unclear, but may reflect impaired blood flow to the sinoatrial node.

Adult↗
PubMed1996

Are heart-lung transplant recipients protected from developing transplant coronary artery disease? A case-matched intracoronary ultrasound study.

BACKGROUND: Accelerated coronary artery disease is a major cause of mortality in heart transplant recipients; however, it does not appear to play a major role in the clinical outcome of heart-lung transplant recipients. The purpose of this study was to determine whether the incidence and severity of transplant coronary artery disease as detected by intracoronary ultrasound in heart-lung transplant recipients are less than those encountered in heart transplant recipients. METHODS AND RESULTS: We studied the left anterior descending coronary artery with the use of intracoronary ultrasound imaging in 22 heart-lung transplant recipients at the time of their routine annual coronary angiogram. Twenty-two heart transplant recipients were case matched for number of years after transplant at ultrasound study, recipient age, donor age, and diagnosis of nonischemic cardiomyopathy. Mean intimal area, intimal index, Stanford class, and incidence of at least moderate disease (Stanford class > or = 3) were measured and calculated in each group and then compared between the two groups. Mean intimal area (1.6 +/- 2.5 versus 3.8 +/- 2.8 mm2), mean intimal index (0.07 +/- 0.10 versus 0.22 +/- 0.14), mean Stanford class (1.7 +/- 1.0 versus 2.7 +/- 1.2), and incidence of Stanford class > or = 3 (14% versus 45%) were significantly lower in the heart-lung transplant recipient group. CONCLUSIONS: The incidence and severity of transplant coronary artery disease are much less in patients receiving heart-lung transplants than in those receiving heart transplants alone.

Adult↗
PubMed1996

Prevalent left ventricular hypertrophy in the predialysis population: identifying opportunities for intervention.

Left ventricular hypertrophy (LVH) is present in over 70% of patients commencing dialysis. It is an independent risk factor for cardiac death, which is the cause of death in approximately 45% of patients in dialysis. The prevalence of LVH in patients earlier in the course of renal insufficiency is unknown. As part of a prospective longitudinal study evaluating the progression of comorbid diseases in patients with progressive renal disease, we evaluated LVH. In 175 consecutive patients attending a renal insufficiency clinic we obtained technically adequate echocardiograms and estimated left ventricular mass index (LVMI) using two-dimensional targeted M-mode echocardiography. We calculated LVMI using the American Society of Echocardiography cube formula method regressed to anatomic validation. The population consisted of 115 men and 60 women ranging in age from 20 to 82 years (mean age, 51.5 years). The mean creatinine was 403 +/- 207 micro mol/L (+/-SD), representing a creatinine clearance (Ccr) of 25.5 +/- 17 mL/min. Left ventricular hypertrophy was defined as LVMI greater than 131 g/m(2) in men and greater than 100 g/m(2) in women, and was present in 38.9% of the population studied. We demonstrate that the prevalence of LVH increased with progressive renal decline: 26.7% of patients with Ccr greater than 50 mL/min had LVH, 30.8% of those with Ccr between 25 and 49 mL/min had LVH, and 45.2% of patients with severe renal impairment (Ccr <25 L/min) had LVH (P = 0.05). The mean LVMI was significantly different among the three groups (97.5 g/m(2) v 114.4 g/m(2), respectively; P < 0.001). Univariate analyses revealed that age, hemoglobin, systolic blood pressure and Ccr were significantly different between the groups with and without LVH. The logistic regression model confirmed the findings of the univariate analysis: an increase in age of 5 years was associated with an increase of 3% in risk of LVH (P = 0.0094), as was an increase in systolic blood pressure of 5 mm Hg (P = 0.0018). For each 10 g/L decrease in hemoglobin, the risk of LVH increased by 6% (P = 0.0062), and for each 5 mL/min decline in Ccr the risk increased by 3% (P = 0.0168). We demonstrate the high prevalence of LVH in patients with renal insufficiency prior to the need for dialysis, which is associated with severity of renal impairment, and identify two modifiable factors (systolic blood pressure and anemia) as important predictors of LVH. We suggest that future studies should focus on interventions aimed at attenuating the impact of these factors.

Adult↗
PubMed1996

Fractional allele loss data indicate distinct genetic populations in the development of non-small-cell lung cancer.

Allelic imbalance or loss of heterozygosity (LOH) has been widely used to assess genetic instability in tumours, and high LOH on chromosome arms 3p, 9p and 17p has been considered to be a common event in non-small-cell lung cancer (NSCLC). We have investigated allelic imbalance in 45 NSCLCs using 92 microsatellite markers on 38 chromosome arms. LOH of 38% was observed on 3p using nine markers, 58% on 9p using 15 markers and 38% on 17p using five markers. Fractional allele loss (FAL) has been calculated for each tumour (FAL is the number of chromosome arms showing LOH/number of informative chromosome arms) and a median FAL value of 0.09 was obtained in the 45 NSCLCs studied. The LOH data were examined on the basis of FAL scores: low FAL (LFAL) (0.00-0.04), medium FAL (MFAL) (0.05-0.13) and high FAL (HFAL) (0.14-0.45) based symmetrically around the median FAL value of 0.09. Tumours with HFAL values showed a very clear polarisation of the LOH data on chromosome arms 3p, 9p and 17p, such that 80% showed loss on 3p, 80% on 9p and 73% on 17p. These incidences of LOH were significantly higher than would be expected, since overall genetic instability in these HFAL tumours ranged from 14% to 45% LOH. Nine of the 14 patients in the LFAL group were found to have no LOH on 3p, 9p or 17p, but five of these had LOH at other sites: i.e. LOH on 5p, 5q, 8p, 13q, 16q and 19q. These results indicate that LFAL patients form a new subset of NSCLC tumours with distinct molecular-initating events, and may represent a discrete genetic population.

Adenocarcinoma↗
PubMed1996

Exercise capacity of heart transplant recipients: the importance of chronotropic incompetence.

BACKGROUND: Maximal exercise capacity is limited in patients after heart transplantation. The extent to which chronotropic incompetence contributes to this intolerance has not been well defined. METHODS: This prospective cross-sectional study examined the heart rate response to exercise and its relation to exercise capacity in 159 heart transplant recipients during progressive, symptom-limited, upright exercise. All prior exercise studies of heart transplant recipients that reported peak oxygen uptake and peak heart rate were also evaluated. RESULTS: Peak oxygen uptake was closely correlated with peak heart rate (r = 0.39, p < 0.001) and maximum increase in heart rate (r = 0.49, p < 0.001) during exercise by our patients. Similar correlations were found in the published studies for peak oxygen uptake versus maximal heart rate (r = 0.54, p < 0.05) and peak oxygen uptake versus increase in heart rate (r = 0.63, p < 0.02). The current study showed that the increase in heart rate from rest to peak exercise was significantly higher and the decline in heart rate after exercise significantly faster for patients 2 or more years after transplantation than for patients less than 2 years after transplantation (46 +/- 2 versus 38 +/- 1.9 beats/min, p < 0.05); the decline in heart rate 4 minutes after exercise was 27 +/- 1.8 versus 16 +/- 1.8 beats/min, respectively ( p < 0.001). CONCLUSION: The reduction in peak oxygen consumption, particularly during the first 2 years, appears to be related in part to chronotropic incompetence. Late after transplantation the heart rate response to exercise is greater and the decline in heart rate after exercise faster, suggesting possible autonomic reinnervation in some patients. Chronotropic incompetence may be an inadequate explanation of oxygen uptake impairment seen late after transplantation, when other factors such as myocardial dysfunction and intrinsic skeletal muscle abnormalities are of increasing importance.

Analysis of Variance↗
PubMed1995

Prophylactic ganciclovir treatment reduces fungal as well as cytomegalovirus infections after heart transplantation.

Cytomegalovirus (CMV) infection is associated with an increased incidence of other opportunistic infections in organ transplant recipients. Whether this is related to immunomodulating effects of CMV or independent of CMV but associated with a host risk factor common to both infections is unclear. The purpose of this study was to determine whether the reduction in CMV infections seen with prophylactic ganciclovir treatment after heart transplantation is associated with a reduced incidence of other opportunistic infections. Of 149 patients prospectively enrolled in a multicenter, randomized, double-blind, placebo-controlled trial of ganciclovir to prevent CMV disease, 74 patients enrolled at this center (33 control and 41 ganciclovir-treated) were retrospectively identified. All received prophylactic OKT-3 and standard 3 drug maintenance immunosuppressive therapy. Actuarial survival and rejection rates and incidence of opportunistic infections (bacterial, fungal, and protozoal) for the 2 treatment groups were determined and compared using Cox-Mantel analysis. CMV disease occurred 2.5 times more frequently in the control group. There were no significant differences in survival or rejection rates nor in bacterial or protozoal infection incidence between the 2 groups. Bacterial infections occurred in 54% of control and 39% of ganciclovir-treated patients (P = 0.18). There were significantly fewer fungal infections in the ganciclovir-treated group (7% vs. 27%, P = 0.0071). CMV and fungal infections were both significantly reduced in patients who received ganciclovir prophylaxis. This suggests that active CMV disease may be causally associated with the development of opportunistic fungal infections.

Adult↗
PubMed1995

The relationship of granzyme A and perforin expression to cardiac allograft rejection and dysfunction.

The mechanisms underlying contractile dysfunction following heart transplantation are poorly defined. To investigate the role of cytotoxic T cells (CTL) in cardiac transplant rejection, and during episodic contractile dysfunction, we performed a prospective study analyzing the expression of granzyme A and perforin, two functional markers of activated CTL. Sixteen consecutive patients were analyzed during the first year posttransplantation. All patients received induction therapy with OKT-3 and received standard three-drug immunosuppression therapy. Rejection status was monitored using routine surveillance endomyocardial biopsy and graded according to the ISHLT scale. Granzyme A and perforin mRNA were detected by reverse transcription PCR at the time of each routine biopsy. A total of 64/123 biopsies were positive for granzyme expression, while 38/123 samples were positive for perforin expression. LV function was monitored using M-mode derived fractional shortening and Doppler assessment of diastolic function (isovolumic relaxation time [IVRT] and pressure half-time [P1/2]). As expected, the presence of granzyme A message was associated with rejection score (ANOVA, P = 0.001). In addition, granzyme A expression was correlated with a decrease in diastolic function (chi 2 = 6.4, P < 0.02), but was not associated with systolic function. The presence of perforin message was not correlated with functional changes or with rejection grade, but was associated with granzyme expression (chi 2 = 9.11, P = 0.0025). These studies suggest that the presence of granzyme A message may be an important predictor of graft function.

Adolescent↗
PubMed1994

Leiomyosarcoma in leiomyomatosis of the small intestine.

Multiple leiomyomata of the small intestine are rare. We report one such case where a leiomyosarcoma had arisen from a leiomyoma in the small intestine 8 years after presentation. The possible origin of the leiomyomata is discussed and it is concluded that small intestinal leiomyomatosis should be regarded as a premalignant condition.

Adult↗
PubMed1994

Combination therapy of cyclosporine with methotrexate and gold in rheumatoid arthritis (2 pilot studies).

OBJECTIVE: To evaluate the efficacy and toxicity of cyclosporine A (CyA) in combination with gold and methotrexate (MTX) in patients with rheumatoid arthritis (RA). METHODS: Twenty patients with RA with partial response to oral MTX and 20 patients with partial response to im gold had CyA added to their regimen for 6 months, withdrawn over 2 months and the patients monitored for 4 months. RESULTS: There was a significant improvement in joint count, joint score, joint swelling, grip strength and joint pain in patients taking the combination with no significant increase in adverse reactions. CONCLUSION: CyA in combination with gold or MTX may, over a 6 month period, increase efficacy in patients with refractory RA without significant increase in toxicity.

Adult↗
PubMed1993

Sequence specificity in the interaction of the four stereoisomeric benzo[c]phenanthrene dihydrodiol epoxides with the supF gene.

The shuttle vector pS189 was treated with each of the four configurational isomers of benzo[c]phenanthrene 3,4-dihydrodiol 1,2-epoxide, and the modified DNA was used as a template in a polymerase arrest assay examining the supF gene. Sites at which polymerase (Sequenase, version 2.0) progress along the template was blocked were presumed to be at or near sites of adduct formation. The polymerase arrest sites were compared with recently reported mutation hotspots induced by these agents in this gene (Bigger et al., Proc. Natl. Acad. Sci. USA, 89: 368-372, 1992). For 31 of 32 mutation hotspots, a polymerase arrest band was present at or 1 or 2 nucleotides 3'- to that site, indicating that adduct formation tended to be associated with mutation hotspots. However, the arrest bands near mutation hotspots were not particularly prominent in all cases, and there were many sites of substantial polymerase arrest that were not in the vicinity of mutation hotspots. Thus, factors in addition to chemical selectivity must play key roles in determining sites of mutation.

Base Sequence↗