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Biomedical subjects

G Ross

Publications and source records attributed to G Ross.

At least 91 records · Page 5Linked to original sources
PubMed1996

Specific cognitive abilities in 2-year-old children with subependymal and mild intraventricular hemorrhage.

Subependymal and mild intraventricular hemorrhages (S/IVH) are likely to affect the subcortical and frontal cortex regions of the brain in premature infants. Damage to the subcortical and frontal areas has been associated with poorer performance in certain abilities, including visual attention, memory for location, and ability to change response set. This study investigated whether S/IVH, occurring at birth, affect these abilities in young children. Two-year-old premature children with S/ IVH, premature children with normal neonatal head ultrasound scans, and full term children with normal births were evaluated on a series of tasks. These tasks were a habituation/novelty preference task (visual attention), Piaget's invisible displacement task (memory for location), an object discrimination reversal task (ability to change response set), and the Bayley Scales of Infant Development (traditional infant test). Premature children with hemorrhage performed significantly less well on the task of ability to remember the last location of a hidden object and on the task of ability to reverse response set. Both groups of premature children performed.

Cerebral Hemorrhage↗
PubMed1996

Increased metabolism of collagen VI in canine osteoarthritis.

The integrity of joint function depends on both the extracellular matrix and the chondrocytes of articular cartilage. It has been suggested that there is a reciprocal relationship between these two components, which is altered in osteoarthritis. The immunohistochemical distribution of type VI collagen in normal and osteoarthritic canine cartilage was investigated by immunofluorescence and immunoelectron microscopy. Immunogold labelling showed that in normal cartilage type VI collagen was concentrated in the capsule adjacent to the chondrocyte complex. However, in osteoarthritic cartilage, type VI collagen was also observed throughout the cartilage matrix and was greatly increased in the territorial matrix and pericellular capsule surrounding the chondrocytes. Naturally occurring canine osteoarthritis provides a useful model for the study of the human disease, particularly the early stages. The changes in type VI collagen observed in osteoarthritis suggest an attempt at cartilage repair, resulting in the reorganization of the matrix.

Animals↗
PubMed1996

Plantar ecchymosis sign: a clinical aid to diagnosis of occult Lisfranc tarsometatarsal injuries.

Diagnosis of subtle Lisfranc injuries can be difficult for the examining clinician. Radiographs do not always reveal the full extent of tarsometatarsal injuries. We describe a clinical sign found in significant Lisfranc injuries that consists of a mid-foot ecchymotic area on the plantar aspect. This implies the potential for significant injury to the plantar tarsometatarsal ligaments. We call this the plantar ecchymosis sign. Patients with this injury and sign should be aggressively evaluated, with early consideration for stress radiographs and ORIF if indicated, as the prognosis of the undertreated Lisfranc injury is poor.

Adult↗
PubMed1996

Pathogenicity and cytadherence of Mycoplasma imitans in chicken and duck embryo tracheal organ cultures.

Two strains of the avian organism Mycoplasma imitans were examined for pathogenicity and cytadherence in chicken and duck embryo tracheal organ cultures, and a virulent strain of the related pathogen Mycoplasma gallisepticum was included for comparison. All consistently cause ciliostasis in tracheal explants from both hosts, and examination of infected tissues by immunofluorescence and transmission electron microscopy demonstrated that M. imitans proliferated on the epithelial surface and adhered to the respiratory epithelium by means of its terminal tip structure in the same manner as M. gallisepticum. These observations endorse the striking phenotypic similarities between M. imitans and M. gallisepticum and suggest that M. imitans may have pathogenic potential in vivo.

Animals↗
PubMed1996

Pathobiology of copper-induced injury in Bedlington terriers: ultrastructural and microanalytical studies.

The pathogenesis of copper (Cu)-induced liver injury has been investigated in Bedlington terriers with familial Cu toxicosis using ultrastructural and microanalytical techniques. Livers from 3 affected and 1 non-affected Bedlington terrier were fixed in 4% paraformaldehyde and 2% glutaraldehyde for transmission electron microscopy and X-ray electron probe microanalysis. Cu analysis was performed on formalin fixed liver by atomic absorption spectrophotometry. In the dog with liver Cu concentration < 2000 micrograms/g, Cu was located only in electron dense lysosomes with minimal cytoplasmic change. With increasing concentrations of liver Cu, the metal became apparent in the nucleus with early signs of nuclear disturbance. In the dog with highest liver Cu content > 7000 micrograms/g X-ray microanalysis identified Cu peaks in lysosomes, nucleus and cytoplasm in descending order with profound cellular changes. The hepatocytes were shrunken with compacted electron dense organelles and the nuclei were contracted, misshapen with chromatin condensation and fragmentation. Apoptotic bodies were identified in sinusoids. It was concluded that excess Cu is initially sequestered in lysosomes but following increasing saturation of this compartment nuclear accumulation of Cu occurs with DNA damage. Apoptosis follows probably by induction of p53 protein.

Animals↗
PubMed1996

Hypocholesterolemia is not associated with neurotoxicity in renal transplant patients.

Cyclosporine-associated neurotoxicity has been reported in recipients of solid organ and bone marrow transplantation. Neurotoxicity during cyclosporine therapy has been suggested to be associated with low levels of serum total cholesterol (TC). We report seven hypocholesterolemic (TC < 150 mg/dl) renal transplant recipients who remained asymptomatic during cyclosporine therapy. Three of these patients were hypocholesterolemic at the time of transplantation and received intravenous cyclosporine as induction therapy. The other four patients became hypocholesterolemic > or = 9 months after renal-transplantation. None of these patients developed neurologic signs or symptoms during cyclosporine therapy. Our short and long-term observations in renal transplant recipients suggest that perhaps factors other than low cholesterol levels may be responsible for cyclosporine-associated neurotoxicity.

Administration, Oral↗
PubMed1996

ATGAM associated coagulopathy in renal transplant patients: a report of two unusual cases.

Polyclonal antibodies, used for both induction and rejection therapy in renal transplant recipients, are associated with such side effects as chills and fever. We describe two patients who developed a coagulopathy during antithymocyte globulin (ATGAM) therapy, a previously unknown complication. The laboratory tests revealed prolonged prothrombin and partial thromboplastin times and thrombocytopenia. Discontinuation of ATGAM therapy resulted in correction of these abnormalities.

Adult↗
PubMed1995

Coexisting extraadrenal pheochromocytoma and renal artery stenosis: a case report and review of the pathophysiology.

The authors report the case of an 8-year-old boy with coexisting malignant extraadrenal pheochromocytoma and ipsilateral renal artery stenosis, severe hypertension, normal urinary vanillylmandelic acid levels, and elevated catecholamines and renin levels. Reported mechanisms of the stenosis are reviewed. The interrelationships of catecholamines, renin, and angiotensin and their effects on renal vasculature are discussed.

Catecholamines↗
PubMed1995

Effects of nicotinic acid and lovastatin in renal transplant patients: a prospective, randomized, open-labeled crossover trial.

Lipid abnormalities are seen frequently in renal transplant patients. Cardiovascular disease is an important cause of morbidity and mortality in these patients. We assessed the efficacy and safety of the lipid-lowering drugs, nicotinic acid (short acting) and lovastatin, the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. Twelve renal transplant patients who had persistent hyperlipidemia despite 6 weeks of dietary treatment participated in this prospective, randomized, open-labeled crossover trial. At 16 weeks, when compared with control values, nicotinic acid (> or = 1.5 g twice a day) significantly reduced the total cholesterol (from 312 +/- 18 [+/- SEM] mg/dL to 229 +/- 19 mg/dL; P = 0.03) and the low-density lipoprotein cholesterol (from 218 +/- 15 mg/dL to 142 +/- 13 mg/dL; P = 0.03) and significantly increased the high-density lipoprotein cholesterol (from 44 +/- 3 mg/dL to 58 +/- 5 mg/dL; P = 0.03). The triglyceride level was reduced from 255 +/- 40 mg/dL to 150 +/- 23 mg/dL (P = 0.09). At 16 weeks, lovastatin therapy (40 mg/d) significantly reduced the total cholesterol (from 285 +/- 13 mg/dL to 233 +/- 10 mg/dL; P = 0.005) and the low-density lipoprotein cholesterol (from 201 +/- 11 mg/dL to 147 +/- 7 mg/dL; P = 0.001). There were no significant changes in the triglyceride and high-density lipoprotein cholesterol levels. Although flushing developed in 67% of patients treated with nicotinic acid, this was not a reason for any of the study dropouts. During this short-term study period no adverse biochemical effects were noted with either of the drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

De novo membranous glomerulopathy in renal allografts with unusual histology.

We describe two cases of de novo membranous glomerulopathy in the renal allograft, with unusual histologic findings. In one patient the allograft nephrectomy specimen showed numerous foam cells in the intima of hyperplastic arteries along with prominent features of chronic rejection. In the other patient, prominent IgM deposits were seen in the glomerular mesangium without chronic rejection.

Adult↗
PubMed1995

Long term effects of ACE inhibitors on the erythrocytosis in renal transplant recipients.

Erythrocytosis is infrequently seen in renal transplant recipients. Both theophylline and angiotensin converting enzyme (ACE) inhibitors have been reported to decrease the elevated hematocrit (Hct) and hemoglobin (Hgb) levels. We studied the efficacy of the ACE inhibitors ramipril (n = 6) and enalapril (n = 1) in seven stable renal transplant recipients. Although the ACE inhibitors significantly reduced the elevated Hct and Hgb levels during the short and long term (Hct 53 +/- 1 vs 48.8 +/- 0.7%; Hgb 17.8 +/- 0.4 vs 16.7 +/- 0.3 vs 16.7 +/- 0.3 gm/dl, at 1 year), the clinical significance of these reductions remains unknown. During therapy there were no significant changes in the blood pressure, serum creatinine and potassium levels and the medications were well tolerated.

Adult↗
PubMed1995

Acquisition and generalization of social skills by high school students with mild mental retardation.

Initial acquisition of social skills by high school students with mild mental retardation was measured during the social skills training game Stacking the Deck. Generalization probes were conducted outside of the training setting (immediately preceding and following training, and 6 weeks posttraining). Due to the high degree of dissimilarity between stimuli in and outside of the training setting, we hypothesized that generalization of skills to nontraining environments would be minimal. Two replications of an initial single-case study were conducted. Students demonstrated acquisition of social skills across game conditions. Immediate generalization of trained social skills did not occur. A possible "deferred generalization" effect was evidenced at 6 weeks posttraining. Results were discussed with respect to the "integrity of common stimuli" and opportunities to respond.

Adolescent↗
PubMed1995

Radiotherapy for primary and secondary brain tumors.

The past 2 years have seen publications of many studies on refinement of conventional radiotherapy using altered fractionation, sensitizers, and high-precision radiotherapy techniques, particularly in the form of stereotactic radiotherapy or radiosurgery. In less common tumors such as cranial germ cell tumors and primary central nervous system lymphoma, the trend towards exploring the role of chemotherapy continues. Mature clinical and experimental studies have also been published that provide detailed and clinically important information on the radiation tolerance of the spinal cord.

Brain Neoplasms↗