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Biomedical subjects

G Ross

Publications and source records attributed to G Ross.

At least 109 records · Page 6Linked to original sources
PubMed1995

De novo malignancy after renal transplantation.

We reviewed the incidence of de novo malignancy in renal transplant recipients who received their grafts between 1979 and 1989, and had at least two years of graft function. Multiple attempts were made to contact 236 patients who were then surviving, or, in whom the medical history could be validated prior to death. There were 94 successful contacts, among whom 19 patients (20.12%) had developed 30 malignant lesions. There were 24 instances of skin and 6 of non-skin malignancy. Squamous cell carcinoma of the skin was the most common new malignancy observed.

Adolescent↗
PubMed1995

Goodpasture's syndrome superimposed on membranous nephropathy. A case report.

We describe a patient with idiopathic membranous glomerulopathy who developed acute deterioration in renal function; this was associated with hemoptysis, severe hypertension, and anti-glomerular basement membrane (anti-GBM) antibody in the serum. Despite aggressive therapy with plasmapheresis, cyclophosphamide and prednisone, the patient progressed to end-stage renal failure and is on maintenance hemodialysis.

Anti-Glomerular Basement Membrane Disease↗
PubMed1994

Survival in patients with recurrent glioma as a measure of treatment efficacy: prognostic factors following nitrosourea chemotherapy.

The assessment of efficacy of treatment in patients with recurrent glioma is notoriously difficult, and survival is the most objective endpoint. Between 1970 and 1992, a cohort of 211 patients with recurrent glioma received nitrosourea-based chemotherapy at the time of disease progression. The median survival from the start of chemotherapy was 7 months, with 30% 1-year and 10% 2-year survival probabilities. One-year survival was 22% in 147 patients with recurrent high-grade astrocytoma, 41% in 37 patients with low-grade astrocytoma and 45% in 24 patients with oligodendroglioma. Age, histological grade and Karnofsky performance status (KPS) at recurrence were independent prognostic factors for survival on multivariate analysis. Based on patients' age, tumour grade and KPS, it was possible to define three distinct prognostic groups with 1-year survival probabilities of 60, 21 and 17% (P < 0.005). Response to chemotherapy was difficult to assess but correlated with prognostic subgroup, with highest response rate (46%) in the most favourable group and lowest (13%) in the poor prognostic group. In patients with recurrent glioma, patient and tumour parameters are the major determinants of outcome which are identical to prognostic factors at the time of primary diagnosis. They can be used to provide prognostic information for the individual patient, and to stratify patients particularly in trials assessing the efficacy of novel treatments.

Adolescent↗
PubMed1994

Obstructive sleep apnea in obese noninsulin-dependent diabetic patients: effect of continuous positive airway pressure treatment on insulin responsiveness.

Patients with noninsulin-dependent diabetes mellitus (NIDDM) are often obese and frequently complain of tiredness. These features are also characteristically seen in patients with obstructive sleep apnea (OSA). Therefore, it was the aim of this study to assess the prevalence of OSA among a group of obese NIDDM patients who have some clinical features of OSA. The effect of reversal of OSA by nasal continuous positive airway pressure (CPAP) treatment on insulin responsiveness was also investigated. From a population of 179 NIDDM patients with a body mass index (BMI) greater than 35 kg/m2, we performed ambulatory sleep monitoring on 31 (15 males and 16 females) who admitted to either heavy snoring or excessive sleepiness. Results were reviewed by a sleep physician blinded to the clinical status of the patients, and 22 (70%) were found to have moderate or severe OSA, with mean oxygen desaturation indexes of 10.3 +/- 5.3 and 30.7 +/- 13.2 episodes/h, respectively. A subgroup of 10 patients (seven males and three females) with a mean BMI of 42.7 +/- 4.3 kg/m2 was treated with nightly CPAP for 4 months. These subjects all had significant OSA, with frequent obstructive apneas (mean, 47 +/- 31.6 episodes/h) and oxygen desaturation (mean minimum O2 saturation, 74 +/- 9.5%), as determined by polysomnography. One patient was excluded from analysis because of infrequent use of CPAP. Insulin responsiveness in terms of glucose disposal measured by hyperinsulinemic euglycemic clamps improved from 11.4 +/- 6.2 to 15.1 +/- 4.6 mumol/kg.min (P < 0.05) during CPAP treatment. These results indicate that OSA occurs commonly in obese NIDDM patients with excessive sleepiness or heavy snoring. Treatment of their OSA may improve insulin responsiveness.

Adult↗
PubMed1994

Effects of dietary therapy on post renal transplant hyperlipidemia. A prospective study.

Hyperlipidemia often occurs after renal transplantation and may contribute to increased cardiovascular morbidity. The National cholesterol education program guidelines (NCEP) recommend dietary modification as the initial therapeutic intervention. We evaluated the effects of the AHA Step I and Step II diets on the serum total cholesterol (TC) and the triglyceride (TG) levels in nondiabetic renal transplant patients. Both the AHA Step I (TC 296 +/- 7 vs 294 +/- 9 mg/dL, p = ns) and Step II diets (TC 282 +/- 8 vs 292 +/- 16 mg/dL, p = ns) failed to significantly lower the serum total cholesterol and the triglycerides levels. During this dietary intervention, the patients' body weight and serum creatinine level remained stable. Our data suggest that neither the AHA Step 1 nor the Step II diet are effective in significantly lowering elevated serum lipids in nondiabetic renal transplant recipients.

Adult↗
PubMed1993

Content of nonhistone protein in nuclei after hyperthermic treatment.

When nuclei were isolated from Chinese hamster ovary cells after being heated, there was a large increase in the amount of 3H-tryptophan labeled nonhistone protein in the nucleus relative to the whole cell. After 15 min or 30 min of heating at 45.5 degrees C, the nuclear nonhistone protein content increased by 1.6 or 1.8, respectively. In contrast, when the nuclear nonhistone protein content was determined in the intact cell by using autoradiography to quantify 3H-tryptophan labeled protein in the nucleus and cytoplasm in sections of fixed cells, the nuclear nonhistone protein content increased by only 1.14 or 1.28 for 15 or 30 min at 45.5 degrees C, respectively. Therefore, heat does not induce a massive movement of cytoplasmic protein into the nucleus.

Animals↗
PubMed1993

Use of the double immuno gel diffusion test and the enzyme-linked immunosorbent assay to distinguish false from true reactors in the complement fixation test for Brucella ovis.

A gel diffusion test with sonicated Brucella ovis antigen and an enzyme-linked immunosorbent assay based on heat-extracted antigen were used to distinguish false from true reactions in a complement fixation test based on heat-extracted antigen. Of 142 complement fixing reactors (occurring in supposedly Brucella ovis-free, accredited flocks), the gel diffusion test correctly identified the status of 139 animals as compared to 128 with the enzyme-linked immunosorbent assay. A combination of the two methods resulted in a correct identification of 141 animals. The procedures provide an easy, cheap and quick way to determine the true status of reactors that show up during routine use of the complement fixation test in Brucella ovis re-accreditation procedures.

Journal Article↗
PubMed1993

Role of L-arginine-derived nitric oxide in cholinergic dilation of gastric arterioles.

The role of L-arginine-derived nitric oxide (NO) in cholinergic vasodilation of resistance vessels was studied in the intact stomach of the rat, utilizing an in vivo microscopy technique. Two L-arginine analogues, NG-monomethyl-L-arginine (L-NMMA) and nitro-L-arginine methyl ester (L-NAME), were used to block NO synthesis. Cholinergic dilation of gastric submucosal arterioles was induced by topical application of various concentrations of acetylcholine (ACh) (10(-7)-10(-4) M). Intravenous but not topical administration of L-NMMA and L-NAME caused an increase in arterial pressure. Intravenous or topical L-NAME reduces resting arteriolar diameter. These findings support the contention that NO formation modulates basal vascular tone and suggest that NO release may play a significant role in the regulation of the gastric circulation. L-Arginine analogues attenuated the arteriolar dilating effect of ACh but not adenosine or nitroglycerin. Substantial arteriolar responses to ACh remained after systemic or topical treatment with either L-NMMA or L-NAME. These results indicate that the L-arginine-NO pathway accounts only in part for ACh-induced vasodilation in gastric resistance vessels in vivo.

Acetylcholine↗
PubMed1993

Boron neutron capture therapy: long-term effects on the skin and spinal cord of the rat.

Our studies of the pharmacokinetics of boron focused on the variations in the concentration in blood of Sprague-Dawley rats with time after the administration of single intravenous doses of 50-200 mg/kg of 10B-enriched sodium mercaptoundecahydro-closo-dodecaborate (BSH). After the lowest dose of BSH there was a progressive decline in the boron content of the blood, with a biological half-life (t1/2) of approximately 4.5 h. Higher doses of BSH resulted in slower boron clearance rates. A dose of 100 mg/kg of BSH was the maximum safely tolerated by the rats. The boron content of the skin at this dose of BSH was a factor of 0.6 lower than that in the blood. To determine the dose-related changes in the response of the central nervous system to BNCT-type radiation exposures, a well-established and clinically relevant model, the rat spinal cord, was used. The spinal cords (20 mm field length) of rats, infused with 100 mg/kg of BSH, were irradiated for 3 to 5 h with cold thermal neutrons from the H6 beam on the DIDO reactor (AERE, Harwell). The skin surface neutron flux was 4.8 x 10(8) n/cm2/s. Exposure times of > or = 4 h resulted in vigorous, biphasic skin reactions, indicative of long-term vascular damage in the dermis. Rats were monitored closely for 84 weeks after irradiation. No abnormal neurological responses were observed and there was no histological evidence of lesions in the spinal cord at the end of the study. These findings indicate that the central nervous system has a high tolerance to BNCT-type radiation using BSH as the neutron capture agent.

Animals↗
PubMed1993

Trityl monitoring of automated DNA synthesizer operation by conductivity: a new method of real-time analysis.

AutoAnalysis is a new method for detecting and quantitating the trityl cation released each cycle on automated DNA synthesizers. The trityl (dimethoxytrityl) cation is removed from the growing oligonucleotide after each base addition and is a useful measure of synthesis efficiency. The traditional absorbance method of collecting each trityl effluent with a fraction collector, followed by dilution with an acid solution and careful quantitation by UV/VIS spectroscopy is costly, tedious and prone to error. The absorbance method for trityl cation analysis must usually wait until the synthesis is complete. Interruption of a failed operation, for a variety of reasons, such as an empty reagent reservoir, is thus not possible. Taking advantage of the conductive properties of the trityl cation, immediate and real-time quantitation is now possible by integrating the total conductance of the flowing stream during the detritylation step after each nucleoside addition in DNA synthesis. A conductivity cell is mounted downstream, past the synthesis column. The conductivity signal is processed and displayed as the current average stepwise yield and overall yield. If the yield drops below a pre-set threshold value because of a failure situation, the synthesizer will interrupt, preserving reagents. AutoAnalysis allows trityl monitoring with complete automation on the Applied Biosystems Models 392 and 394 DNA/RNA Synthesizers.

Base Sequence↗