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Biomedical subjects

L Gray

Publications and source records attributed to L Gray.

At least 73 records · Page 4Linked to original sources
PubMed1998

Dementia associated with hyperphosphatemic tumoral calcinosis.

Hyperphosphatemic tumoral calcinosis (HTC) is a rare inherited metabolic disorder manifested by pararticular calcification and hyperphosphatemia, caused by an elevated renal phosphate reabsorption threshold and elevated serum 1,25-dihydroxyvitamin D levels. The disorder usually affects African-American subjects, but has also been described in Caucasians and Hispanics. Vascular calcifications and angioid streaks have been reported to be associated with the disorder; however, dementia has not been previously reported. Our medical center has followed two African-American siblings, with HTC for over 30 years, who have developed dementia at 56 years and 67 years of age. Neither man has been hypertensive, however, magnetic resonance imaging (MRI) scans in both cases revealed multiple periventricular infarcts, suggestive of infarcts caused by vascular calcification in the central nervous system. These two brothers with HTC suggest that periventricular infarcts with dementia may be a long term complication of this disorder.

Aged↗
PubMed1998

One-methyl group metabolism in non-ketotic hyperglycinaemia: mildly elevated cerebrospinal fluid homocysteine levels.

Non-ketotic hyperglycinaemia (NKH) is a rare, severe brain disease caused by deficient glycine cleavage enzyme complex activity resulting in elevated glycine concentrations. Recent experience suggests that factors in addition to glycine kinetics are involved in its pathogenesis. The glycine cleavage reaction through the formation of methylenetetrahydrofolate is an important one-methyl group donor. A deficiency in one-methyl group metabolites, in particular of choline, has been hypothesized in NKH. We investigated metabolites involved in one-methyl group metabolism in plasma and CSF of 8 patients with NKH, and monitored the effect of treatment with choline in one patient. Plasma and CSF choline and phosphatidylcholine concentrations were normal, except for a low plasma choline in the single neonate studied. Choline treatment did not change brain choline content, and was not associated with clinical or radiological improvement. Methionine concentrations and, in one-patient, S-adenosylmethionine and 5-methyltetrahydrofolate concentrations were normal in CSF. Homocysteine concentrations in CSF, however, were slightly but consistently elevated in all four patients examined, but cysteine, cysteinylglycine and glutathione were normal. Serine is important in the transfer of one-methyl groups from mitochondria to cytosol. Serine concentrations were normal in plasma and CSF, but dropped to below normal in CSF in three patients on benzoate treatment. These observations add to our understanding of the complex metabolic disturbances in NKH.

Amino Acid Metabolism, Inborn Errors↗
PubMed1998

Psychological distress and the frequency of perfectionistic thinking.

Five studies tested the hypotheses that there are individual differences in the frequency of automatic thoughts involving perfectionism and that these thoughts are associated with psychological distress. Research with the Perfectionism Cognitions Inventory (PCI) established that this new measure has adequate psychometric properties, and high PCI scorers tend to spontaneously report perfectionistic thoughts in naturalistic situations. Additional research confirmed that frequent perfectionism thoughts account for unique variance in distress, over and above variance predicted by standard measures of negative automatic thoughts and trait perfectionism measures. Overall, the findings support the view that personality traits involved in depression and anxiety have a cognitive component involving ruminative thoughts and that activation of this cognitive personality component contributes to distress.

Adult↗
PubMed1998

Diagnosis of intracranial vasculitis: a multi-disciplinary approach.

Intracranial vasculitis, or primary angiitis of the central nervous system (PACNS), is an uncommon, often fatal disorder that frequently responds to aggressive immunosuppressive therapy. Magnetic resonance imaging (MRI), cerebral angiography, and brain biopsy are diagnostic modalities that vary in invasiveness and diagnostic accuracy. The purpose of this study was to determine whether certain clinical or radiologic features were predictive of a diagnostic biopsy. Thirty consecutive patients undergoing brain biopsy to "rule out vasculitis" were studied. Nine patients demonstrated granulomatous or lymphocytic vasculitis, 1 had lymphocytic vasculitis and encephalitis secondary to arbovirus infection, 5 had thickened vessels consistent with hypertensive changes, 5 had amyloid angiopathy and/or changes of Alzheimer disease, 5 demonstrated no pathologic abnormalities, and 1 each had acute infarct, vascular malformation, aneurysm, acellular fibrinoid necrosis, and demyelination. The spectrum of MRI and angiographic changes associated with PACNS were nonspecific, overlapping extensively with changes of chronic hypertension and amyloid deposition. The predictive values of brain biopsy (90-100%) were significantly higher than those of angiography (37-50%) or MRI (43-72%). In this study, morbidity associated with aggressive immunosuppression was significantly greater than that associated with cerebral angiography or brain biopsy. Thus, wedge biopsy of cortical and leptomeningeal tissues is central to the multi-disciplinary approach to a patient with clinical suspicion of PACNS.

Adult↗
PubMed1998

Overview of diffusion imaging.

Diffusion is a major advance in the continuing evolution of MR imaging. It provides contrasts and characterization between tissues at a cellular level that may imply differences in function as well as framework. With the development of echo-planar imaging (EPImh54) diffusion the quality of the data will be such that clinically relevant information can result, and thus clinical usage of EPI diffusion will increase. Many potential applications of diffusion have not yet been explored.

Brain↗
PubMed1998

Nucleic acid vaccines against hepatitis viruses.

Direct DNA intramuscular or intradermal injection of plasmids containing viral genes under the control of viral promoters is an efficient means of stimulating both class I and class II-mediated antiviral responses. Viral hepatitis B and C are suitable candidates for this approach, particularly as therapeutic immunogens for chronically infected individuals. Several groups have shown that the S gene of HBV is expressed in murine muscle and stimulates a high titre and long-lasting anti-HBs response. Uniquely, CD8+ CTL responses are also induced to HBsAg. No vaccine exists for HCV. Therefore the structural genes (C + E1 + E2) have been cloned as a 2,831 bp fragment from a genotype la isolate into the vector pcDNA3. The resulting plasmid DNA was injected directly into the quadriceps muscle of three-week-old BALB/c mice. Intracellular-expressed E1 and E2 proteins thus represent the complete spectrum of native structural epitopes, including those dependent on glycosylation and protein folding. Mouse antisera were tested for reactivity against conserved sequences using overlapping 7-mer peptides. Two conserved, overlapping epitopes were identified in E2 spanning residues 581-591 and 590-603. This domain represents one of seven major E2 antigenic domains recognized by HCV human antibodies, one of three with antigenic homologies to related flavivirus proteins. Thus antigen is presented with high efficiency following DNA injection and offers the potential of high rates of seroconversion and virus clearance in those predisposed to virus-induced chronic liver disease.

Animals↗
PubMed1998

Close relationships of violent and nonviolent African American delinquents.

One hundred and one incarcerated African American adolescent delinquents, 51 violent and 50 nonviolent were contrasted on background variables and measures of close relationships. Violent delinquents were found to be older, have a greater number of arrests, lower reading achievement scores, and were more likely to have a criminal parent in the home. Violent, as compared with nonviolent delinquent, showed differences in close relationships. Violent delinquents were more likely to perceive their mothers as showing more rejection/undifferentiated behavior and their attachments, mainly to hetero-sexual partners, were more anxious. The results were interpreted in terms of both quantitative and qualitative distinctions between violent and nonviolent delinquents, with violent delinquents showing greater impairment.

Achievement↗
PubMed1997

Functional mapping of glomus tumors reveals underlying embryology.

A functional map of cranial nerves was created by the multidimensional scaling (MDS) of adults' symptoms from glomus tumors. Differences between cranial-nerve deficits in eight different subsets of glomus tumors were input to MDS. MDS determines coordinates of points (representing cranial nerves) such that distances between points are related as closely as possible to differences in the observed symptoms. For example, two nerves that are equally likely to be affected by a glomus tumor would be put close together in the calculated map, even though they may be physically distant. The result resembles a stage in the developing nervous system. This correlation provides mathematical confirmation that adults' glomus tumors are related to early embryology. This in turn suggests that functional maps can provide a useful way for computers to depict underlying patterns in medical data.

Adult↗
PubMed1997

Overcoming right ventricular failure with left ventricular assist devices.

BACKGROUND: Right ventricular failure can lead to circulatory collapse while on left ventricular assist device support. By shunting blood from the femoral vein to the left ventricular assist device, cardiac output can be increased, but arterial oxygen saturation will decrease. METHODS: To determine the effects on O2 delivery, a model was developed on the basis of O2 uptake in the lungs and whole body O2 consumption. An equation was derived that related cardiac output, pulmonary venous O2 saturation, O2 consumption, and the ratio of shunt-to-systemic blood flow to systemic O2 delivery. RESULTS: When total cardiac output increases, the shunt will increase systemic O2 delivery while decreasing arterial O2 saturation and leaving systemic venous O2 saturation unaltered. When total output does not increase, the shunt will decrease systemic O2 delivery, arterial O2 saturation, and systemic venous O2 saturation. CONCLUSIONS: The analysis suggests that measuring systemic venous oxygen saturation may be a useful way to monitor patient safety. A decrease in systemic venous O2 saturation when creating the shunt implies an inadequate increase in cardiac output.

Cardiac Output↗
PubMed1996

Triacylglycerol and cholesterol transport during absorption of glycerol trioleate vs. glycerol trielaidate.

We used conscious, chronic lymph-fistula rats to compare intestinal lymphatic transport of glycerol trioleate (TO) vs. glycerol trielaidate (TE) and to determine the effect of TO vs. TE on absorption and transport of cholesterol. Rats were implanted with intestinal lymph fistulas and duodenal cannulas and then given intraduodenal infusions of lipid emulsions containing purified TO or TE (40 mumol/h) and cholesterol (7.8 mumol/h + 2 microCi [14C]cholesterol). Lymph samples were collected at 0, 2, 4, 5, 6, 7, and 8 h after the start of lipid infusion. Lymphatic output and luminal and gut wall recovery of radioactive lipid at 8 h were quantified. Triacylglycerol (TG) fatty acid isomers did not affect lymphatic output of TG; lymph TG fatty acid composition and output reflected infusate composition. Lymphatic output of cholesterol (mass and radioactivity) did not differ between groups; luminal and gut wall recovery of [14C]cholesterol was also similar between groups. Similar lymphatic transport of TG and cholesterol between triolein- and trielaidin-infused rats was maintained for up to 16 h after the cessation of an infused lipid load. These results indicate that TO and TE are transported into lymph similarly, and that cholesterol absorption and transport are similar irrespective of whether TO or TE is the TG source. The data suggest that trans fatty acid-induced hypercholesterolemia is not due to altered intestinal absorption and transport of cholesterol.

Animals↗
PubMed1996

Intestinal lipid absorption in the nephrotic rat.

There is limited data on intestinal lipid absorption in the nephrotic syndrome. This study investigated whether the efficiency of intestinal lipid absorption is altered in nephrotic lymph-fistula rats. The nephrotic syndrome was induced in nine Sprague-Dawley rats by an i.v. injection of puromycin aminonucleoside in saline; seven control rats received saline only. At 10 to 14 days after injection, the main intestinal lymph duct was cannulated for collection of lymph. The duodenum was also cannulated and a fasting saline-glucose solution was infused overnight at 3 mL/h. The next day, the infusate was changed to a lipid emulsion that contained (14C) cholesterol and (3H)triglyceride (triolein) that was infused at 3 mL/h for 8 h. During the last hour of fasting and during the lipid infusion, lymph flow in the Nephrotic group averaged 0.6 mL/h higher than the Control group (P = 0.02). No significant differences were found between the two groups in recovery of infused radioactive cholesterol (P = 0.37) or triglyceride (P = 0.38) from the gastrointestinal lumen, small intestinal mucosa, or lymph. Lymphatic output of chemically measured cholesterol was also similar (P = 0.96). These results suggest that mucosal uptake and lymphatic output of cholesterol and triglyceride are not altered in the nephrotic syndrome.

Animals↗
PubMed1996

Transcranial doppler sonography to monitor cerebral vasculitis.

We describe a patient with cerebral vasculitis treated with prednisone and cyclophosphamide and followed by serial transcranial Doppler sonography and arteriography. Proximal cerebral angiographic abnormalities correlated with transcranial Doppler abnormalities. The abnormalities gradually normalized with treatment and correlated with the findings of followup arteriography, which also showed improvement in the vascular morphology. Transcranial Doppler sonography is useful in following proximal cerebral vascular abnormalities in some cases of cerebral vasculitis.

Angiography↗
PubMed1995

Designing a funding system for rehabilitation services. Part 2: Policy objectives and options for achieving efficiency and quality of care.

This paper examines the objectives of a funding policy for rehabilitation services. A casemix funding system comprises two sets of instruments: a classification system and a payment system. Attention is given to identifying which policy objectives are best pursued through each of these instruments. The paper then analyses the effect of various instruments on creating incentives for efficiency and quality, and assesses policy options with regard to their capacity for dealing with the heterogeneity of rehabilitation patients and controlling various forms of gaming. In conclusion, the paper canvasses four major areas warranting consideration in advancing policy: the use of a blended payment system; dealing with functional gain; the development of an information base; and the focus on designated rehabilitation units.

Australia↗
PubMed1995

Stroke due to recurrent ipsilateral carotid artery dissection in a young adult.

BACKGROUND: Extracranial carotid artery dissection is a well-recognized cause of ischemic stroke. Recurrent carotid artery dissections are infrequent. Recurrent ipsilateral dissection has only rarely been documented and has not been pathologically verified. CASE DESCRIPTION: A 33-year-old woman presented with a left parieto-occipital ischemic stroke. Angiography demonstrated a pseudoaneurysm of the extracranial left internal carotid artery. There was no angiographic evidence of an underlying vasculopathy. The pseudoaneurysm was resected, and microscopic examination revealed features most consistent with fibromuscular dysplasia with areas of both chronic and recent dissection. CONCLUSIONS: This case suggests that the frequency of fibromuscular dysplasia as a cause for "idiopathic" spontaneous carotid artery dissection may be higher than previously recognized and that recurrent embolization may occur in the setting of chronic dissection due to redissection of the previously involved vessel.

Adult↗