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Biomedical subjects

C Adams

Publications and source records attributed to C Adams.

At least 91 records · Page 5Linked to original sources
PubMed1997

Onset of speech after left hemispherectomy in a nine-year-old boy.

Case Alex, with Sturge-Weber Syndrome affecting the left hemisphere, failed to develop speech throughout early boyhood, and his comprehension of single words and simple commands remained stagnant at an age equivalent of 3-4 years. But then, following left hemidecortication at age 8.5 years and withdrawal of anticonvulsants when he was more than 9 years old, Alex suddenly began to acquire speech and language. He also showed an unusual degree of residual motor capacity on his right side. Alex's remarkable progress in learning speech and language, and the development of his other cognitive abilities, were measured periodically from the age of 9 to 15 years. His most recent scores on tests of receptive and expressive language place him at an age equivalent of 8-10 years. Comparison with the level of function attained in these domains by nine other left hemispherectomized patients with early onset of disease and comparable IQ (range, 40-68) but with early development of speech and language, suggests that, surprisingly, Alex has suffered no permanent disadvantage from his protracted period of mutism and severely limited comprehension. Although the findings in Alex, as in other left-hemispherectomized patients, indicate define limits to the cognitive and linguistic capacity of the isolated right hemisphere, Alex's achievements appear to challenge the widely held view that early childhood is a particularly critical period for acquisition of speech and language or any of their selective aspects, including phonology, grammar, prosody and semantics. It is concluded that clearly articulated, well structured, and appropriate language can be acquired for the first time as late as age 9 years with the right hemisphere alone.

Adolescent↗
PubMed1997

Adult age-group differences in recall for the literal and interpretive meanings of narrative text.

This study examined age differences in recall for the literal and interpretive meanings of narrative text. Following presentation of one of two stories rich in both literal and interpretive content, younger (mean age = 19.2 years) and older (mean age = 72.2 years) adults were asked to retell and to interpret the story. Response task order was counterbalanced across participants. When asked to retell a story as close to the original as possible, the younger adults recalled more of the literal propositional content than did the older adults in the retell-first, although not in the interpret-first, condition. In addition, both older and younger adults recalled more of the main ideas (gist) relative to the details. When asked to interpret the same story, more older than younger adults produced deep and synthetic representations of the story's interpretive meanings. In addition, there was a clear preference among the older age group for deep-synthetic responding. Although more younger than older adults produced analytic interpretations, within the younger group there was no clear preference for either an analytic or a deep-synthetic style.

Adolescent↗
PubMed1997

Randomized trial of high nutrient density formula versus standard formula in chronic lung disease.

To test the hypothesis that the nutrient intake and growth of infants with chronic lung disease would be improved by providing nutrients in more concentrated form, and that the lower volume would improve respiratory status, 60 preterm infants requiring supplemental oxygen at 28 days of age were randomly assigned a low-density (24 kcal/oz) formula fed at 180 ml/kg/day, or a high-density (30 kcal/oz) formula at 145 ml/kg/day. There was no difference in growth, respiratory outcome, oedema or diuretic requirement between dietary groups. Infants fed the high nutrient density formula had significantly greater total energy (143 vs 134 kcal/kg/day) and protein (3.9 vs 3.6 g/kg/day) intakes, largely because the low-density formula group did not achieve the designated 180 ml/kg/day. In conclusion, use of a high-density formula in infants with chronic lung disease did not improve growth or respiratory outcome, despite a small increase in total energy and protein intake.

Energy Intake↗
PubMed1997

Alzheimer's disease research: a game of connect the dots.

Although a vast number of experimental investigations have focused on various aspects of Alzheimer's disease (AD), the pathogenic mechanism of the disease has not been established. AD research is a dynamically changing field that has entertained a variety of hypotheses. Since most of the data pertaining to AD pathogenesis is obtained in postmortem tissue or in vitro experiments, researchers must play a game of 'connect the dots' to try to correlate the diverse aspects of the disease and generate hypotheses regarding the sequence of pathological events. This article reviews the current state of AD research, and presents three hypothetical models for disease progression.

Alzheimer Disease↗
PubMed1997

Clinical and molecular analysis of a pedigree of southern Italian ancestry with spinocerebellar ataxia type 2.

We describe patients from five generations of a pedigree with mutations in the spinocerebellar ataxia type 2 gene (SCA2). The predominant clinical features observed included both appendicular and truncal ataxia, dysarthria, slowness of saccades, and impaired optokinetic responses. Successive generations demonstrated both earlier ages of onset as well as increasing numbers of trinucleotide repeat sequences. The signs found in this family are compared with the description of other families with SCA2 as well as with other types of dominantly inherited spinocerebellar ataxias.

Adolescent↗
PubMed1997

Cyclosporin treatment of perianal fistulas in dogs.

The purpose of this pilot study was to investigate the efficacy of cyclosporin in treating perianal fistulas (PAF) in dogs. Based on resolution of all fistulas in all dogs with remission times up to > 18 months, we conclude that cyclosporin therapy is the treatment of choice for PAF in dogs.

Animals↗
PubMed1997

[Calculation of the regurgitation fraction in mitral insufficiency by Doppler echocardiography using a study of the zone of flow convergence].

The aim of this study was to propose a new method for calculating the regurgitation fraction of mitral insufficiency by the proximal isovelocity surface area (PISA) method and to compare it with the value of the catheter regurgitation fraction. Thirty-five patients (21 men and 14 women) aged 59 +/- 13 years with isolated mitral insufficiency were studied. Analysis of the proximal isovelocity surface area enabled calculation of an instantaneous maximum regurgitant flow, surface of the regurgitant orifice and the regurgitant volume. The regurgitant fraction was calculated by dividing the regurgitant volume by the sum of the regurgitant volume and aortic stroke volume measured by Doppler echocardiography. These parameters were compared with the corresponding catheter data and the angiographic grade of mitral insufficiency. The echocardiographic and catheter studies were performed within 1.7 +/- 1.2 days. There was a statistically significant correlation between the instantaneous maximum regurgitant flow calculated by the PISA method and the catheter regurgitant flow (r = 0.88; p = 0.0001); between the regurgitant volume calculated by the PISA method and the catheter regurgitant volume (r = 0.85; p = 0.0001) and the regurgitation fraction calculated by the PISA method and the catheter regurgitant fraction (r = 0.82; p = 0.0001). A regurgitant fraction by the PISA method of > 45% corresponded to severe mitral regurgitation (> or = angiographic grade 3 and/or a catheter regurgitant fraction > or = 50%) with a sensitivity of 88% and a specificity of 100%. The PISA method should form part or routine quantification of mitral insufficiency.

Adult↗
PubMed1996

Expression of insulin-like growth factor-1 (IGF-1) and IGF-binding protein 2 (IGF-BP2) in the hippocampus following cytotoxic lesion of the dentate gyrus.

Receptor binding and gene expression of several members of the IGF gene family were examined in the rat brain following lesion of the hippocampal dentate gyrus granular cells by intradentate colchicine injection. Dentate granular cell loss was accompanied by extensive reactive gliosis in the lesioned hippocampus and damaged overlying cortex, as verified by the increase in GFAP mRNA and BS-1 lectin binding. At 4 days post-lesion, 125I-IGF-2 binding was dramatically increased within the lesioned dentate gyrus and damaged overlying cortex, and corresponded temporally and anatomically with increased IGF-BP2 gene expression following the lesion. Increased IGF-BP3 gene expression was only observed in the overlying cortex at 10 days post-lesion, and corresponded with an increase in 125I-IGF-1 binding at the injured surface of the cortex. Type-2 IGF receptor mRNA expression was reduced to background levels in the lesioned dentate gyrus, suggesting that IGF-BP2 was a major component of the observed increase in 125I-IGF-2 binding. In situ hybridization also revealed a prominent increase in IGF-1 mRNA expression by 4 days post-lesion, which was localized within the lesioned dentate gyrus and damaged cortical areas, and was shown to be expressed by microglia. While no IGF-2 mRNA expression was observed within the CNS, either prior to, or following the lesion, IGF-2 mRNA expression was observed in the choroid plexus, meningeal membranes, and in blood vessel endothelium, providing a potential source for the transport of IGF-2 into the CNS. In the injured CNS, increased IGF-BP2 expression may act to maintain or transport IGF-1 or IGF-2, as well as modulate the local autocrine and paracrine actions of the IGFs. Increased microglial IGF-1 expression following colchicine treatment correlates with the timing of a number of post-traumatic events within the CNS, suggesting that IGF-1 may have a role as a neuroprotectant for surviving neurons and signal for local neuronal sprouting, as well as a role in reactive astrogliosis.

Animals↗
PubMed1996

Prospective evaluation of dynamic contrast enhanced magnetic resonance imaging in the evaluation of fistula in ano.

Forty-two patients with a suspected diagnosis of fistula in ano underwent prospective comparison of digital rectal examination, dynamic contrast enhanced magnetic resonance imaging (DCEMRI) and surgical exploration. There were five discordancies: DCEMRI showed an ischiorectal abscess and track with no enteric connection in one patients who at operation was found to have a well epithelialized primary fistula. Four patients with fistulas on DCEMRI had no enteric opening found at surgery and were treated as having sinuses. Long-term follow-up has shown failure to heal in all patients and further surgery confirmed missed fistula. Compared with final outcome measures DCEMRI had a sensitivity of 97 per cent and specificity of 100 per cent in the detection of fistula. DCEMRI also identified more secondary tracks and was more accurate at identifying complex fistulas than either digital rectal examination alone or surgical exploration.

Adult↗
PubMed1996

Reduced transmitter release conferred by mutations in the slowpoke-encoded Ca2(+)-activated K+ channel gene of Drosophila.

Potassium channels control the repolarization of nerve terminals and thus play important roles in the control of synaptic transmission. Here we describe the effects of mutations in the slowpoke gene, which is the structural gene for a calcium activated potassium channel, on transmitter release at the neuromuscular junction in Drosophila melanogaster. Surprisingly, we find that the slowpoke mutant exhibits reduced transmitter release compared to normal. Similarly, the slowpoke mutation significantly suppresses the increased transmitter release conferred either by a mutation in Shaker or by application of 4-aminopyridine, which blocks the Shaker-encoded potassium channel at the Drosophila nerve terminal. Furthermore, the slowpoke mutation suppresses the striking increase in transmitter release that occurs following application of 4-aminopyridine to the ether a go-go mutant. This suppression is most likely the result of a reduction of Ca2+ influx into the nerve terminal in the slowpoke mutant. We hypothesize that the effects of the slowpoke mutation are indirect, perhaps resulting from increased Ca2+ channel inactivation, decreased Na+ or Ca2+ channel localization or gene expression, or by increases in the expression or activity of potassium channels distinct from slowpoke.

4-Aminopyridine↗
PubMed1996

Regional gene expression of the glutamate receptor subtypes GluR1, GluR2, and GluR3 in human postmortem brain.

Although glutamatergic receptors are localized throughout the mammalian central nervous system (CNS), the specific cellular localization of the various glutamatergic receptor subtypes throughout human brain remains largely unknown. PCR fragments to human GluR1, GluR2, and GluR3 receptor subtypes were cloned and used as probes for in situ hybridization in order to examine the anatomical and cellular localization of glutamate receptor subtype gene expression in dissected regions of human postmortem brain tissue. Although hybridization was observed throughout the CNS, results indicated that the highest levels of hybridization were in the hippocampus, with localization primarily to cells in the pyramidal cell layer of the CA1-CA3 region, and the granular cells of the dentate gyrus. Prominent hybridization also was observed in the medium to large neurons of the cingulate cortex, temporal lobe, septum, and amygdala, as well as in scattered neurons in the thalamus, cerebral cortex, and medulla. A striking pattern of differential hybridization was observed within the cerebellum. GluR1 demonstrated light hybridization along the Purkinje/Bergmann glia layer, with GluR2 and GluR3 demonstrating hybridization to Purkinje cells, and GluR3 also to cells within the molecular layer, previously identified as stellate-basket cells. Changes in glutamate receptor function have been shown to be important in the pathogenesis of a number of neurological disorders. Therefore, an examination of glutamatergic receptor expression in human postmortem brain tissue may provide important information on the molecular basis of a variety of neurological and psychiatric disorders of the CNS.

Base Sequence↗
PubMed1996

Middle cerebral artery dissection.

A 12-year-old girl had minor head trauma, with resultant mild headache, one day prior to onset of an apparently generalized tonic clonic seizure, right hemiparesis and dysphasia. A cranial CT scan showed evidence of a left middle cerebral artery infarct. Despite ventilation, fluid restriction, mannitol, thiopental infusion and intracranial pressure monitoring she deteriorated and died. Autopsy demonstrated dissection of the left middle cerebral artery with an intact internal carotid artery and no evidence of vasculitis. Middle cerebral artery dissection in children is very rare. Most reported cases are diagnosed at autopsy. The pathogenesis of cerebral artery dissection may include preceding minor head trauma or exertion and this should be sought for in the history.

Accidents, Home↗
PubMed1996

Interaction between nutrition and Eimeria acervulina infection in broiler chickens: development of an experimental infection model.

In three experiments broiler chickens were inoculated with sporulated Eimeria acervulina oocysts at 18 d of age. Feed intake, body-weight gain, brush-border enzyme activities, fat digestion, protein digestion and protein retention were measured. Body-weight gain was reduced during the acute phase of the infection and increased during the recovery phase of the infection. Feed intake was decreased on day 4 and day 5 postinfection (PI) and increased from day 7 to day 11 PI. Maltase (EC 3.2.1.20) and sucrase (EC 3.2.1.48) activities were decreased on day 5 PI in all intestinal segments. In Expts 2 and 3, however, maltase activity was increased in the ileum. Fat digestion was decreased from day 2 to day 11 PI. N digestion and retention were decreased from day 2 to day 11 PI.

Animal Nutritional Physiological Phenomena↗
PubMed1996

Interaction between nutrition and Eimeria acervulina infection in broiler chickens: diet compositions that improve fat digestion during Eimeria acervulina infection.

Previously an experimental infection model was developed in which broiler chickens were inoculated with sporulated Eimeria acervulina oocysts at an age of 18 d. The infection resulted in adverse performance results and reduced nutrient digestion. In two new experiments with the infection model effects of diet adjustments on fat digestion were investigated. In the first experiment addition of 0.4 g cholic acid/kg to a diet rich in animal fat resulted in increased fat digestion during the infection. In the second experiment replacing animal fat by coconut oil resulted in improved fat digestion during the coccidiosis infection. However, replacement of animal fat by soybean oil did not improve fat digestion.

Animal Nutritional Physiological Phenomena↗
PubMed1996

Nicotinic receptor function in schizophrenia.

Schizophrenia can be partially characterized by deficits in sensory processing. Biochemical, molecular, and genetic studies of one such endophenotype, the P50 auditory-evoked potential gating deficit, suggest that one of the neuronal nicotinic receptors, the alpha 7 nicotinic receptor, may function in an inhibitory neuronal pathway involved in this phenotype. The P50 deficit is normalized in nongating subjects by nicotine. Although most schizophrenia patients are heavy smokers, the effects of nicotine may be transient, as alpha 7 receptors are known to desensitize rapidly. In an animal model of the P50 gating deficit, antagonists of the alpha 7 nicotinic receptor block normal gating of the second of paired auditory stimuli. Regional localization of receptor expression includes areas known to function in sensory filtering. An inhibitory mechanism, in the hippocampus, may involve nicotinic stimulation of gamma-aminobutyric acid (GABA)ergic interneurons, resulting in decreased response to repetitive stimuli. Expression of the alpha 7 receptor is decreased in hippocampal brain tissue, dissected postmortem, from schizophrenia subjects. The P50 deficit is inherited in schizophrenia pedigrees, but it is not sufficient for disease development and thus represents a predisposition factor. Linkage analysis between the P50 deficit in multiplex schizophrenia pedigrees and deoxyribonucleic acid (DNA) markers throughout the genome yielded positive lod scores to DNA markers mapping to a region of chromosome 15 containing the alpha 7 nicotinic receptor gene. Elucidation of possible interactions of the P50 with other factors, known to be important in the etiology of the disease, is important in determining an overall pathobiology of schizophrenia.

Animals↗