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Biomedical subjects

A Thomas

Publications and source records attributed to A Thomas.

At least 289 records · Page 16Linked to original sources
PubMed1996

Hearing aids and glue ear.

This study was designed to determine the acceptance and effectiveness of a hearing aid in the management of children with persistent hearing loss due to glue ear (otitis media with effusion [OME]). Forty-eight children with OME, in whom the main symptom was deafness, were treated with a hearing aid instead of surgery and reviewed at 3-monthly intervals over 6-12 months. Seventy-one per cent reported unequivocal satisfaction with the aid. Sixty-five per cent used the aid continuously throughout the day whilst 35% used it only at specific times of need. Ninety-eight per cent noticed a definite improvement in their hearing whilst using the aid and this was confirmed audiometrically in 100%. Disability was considered in terms of speech development and educational achievement. In 66% there had been a subjective decline in these parameters prior to aid prescription. In all but one child significant improvement was made sufficient to alleviate parental and teachers' concern. No children reported significant symptoms due to OME other than deafness and there were no complications of hearing aid usage. At follow-up, however, 13% of children continued to use a hearing aid in an ear in which the OME had resolved. This study has shown that in this preselected group of children with persistent OME and the predominant symptom of deafness, a hearing aid was an effective treatment for their deafness with high acceptance and compliance.

Audiometry, Pure-Tone↗
PubMed1996

Missed cervical spine injury following barflying.

The case is reported of a young woman who suffered a wedge fracture of C7 due to axial loading with a flexed spine, in an injury caused by barfly jumping. The fracture was unstable and required surgical stabilisation. In this case the seriousness of the injury was not realised at first because neck radiographs were not taken at her initial assessment in accident and emergency.

Accidental Falls↗
PubMed1996

Water turnover and body composition during long-term exposure to high altitude (4,900-7,600 m).

Thirteen healthy subjects (11 men and 2 women; 30.2 +/- 5.4 yr; 73.5 +/- 10.3 kg; 178.9 +/- 10.4 cm; body mass index, 22.9 +/- 1.6 kg/m2) participated at the 62-day expedition to the Broad Peak (8,047 m), Pakistan. Weight, body water, and water turnover (deuterium dilution and elimination) were measured eight times to assess long-term changes. Body weight fell during the ascent to the base camp [from 73.2 +/- 9.8 (baseline) to 71.7 +/- 9.7 kg; P < 0.05] and decreased until the end of the base camp stay (66.7 +/- 7.2 kg; P < 0.0001). Body compartments changed at different rates. Total body water decreased during the ascent (from 43.1 +/- 7.3 to 41.0 +/- 7.7 liters; P < 0.05) and remained unchanged until the base camp was reached (41.2 +/- 6.9 liters; P < 0.01) but decreased further during the base camp stay (40.6 +/- 5.2 liters). Water content of the body (total body water-to-body weight ratio) fell during the ascent (from 58.6 +/- 3.4 to 55.8 +/- 4.4%; P < 0.01), approached the baseline value during the base camp (57.4 +/- 4.0 and 58.3 +/- 5.1%), and increased again until the end of the base camp (60.6 +/- 3.4 and 60.9 +/- 4.3%). The compartment of the solids increased during the ascent (from 30.2 +/- 3.4 to 32.2 +/- 4.9 kg; P < 0.01) and approached the baseline value on arrival at the base camp (30.5 +/- 4.7 kg). Until the end of the base camp, the compartment of the solids fell (26.9 +/- 2.6 and 26.1 +/- 4.0 kg), indicating that weight loss was due to a loss of body solids, presumably mostly fat mass. Water turnover during the pretest period (sea level) was 45 +/- 7 ml.kg-1.day-1; it increased during the ascent (56 +/- 11 and 60 +/- 10 ml.kg-1.day-1) but remained constant during the base camp stay (63 +/- 12, 58 +/- 9, and 56 +/- 10 ml.kg-1.day-1). It increased during the ascent to Broad Peak (73 +/- 20 ml.kg-1.day-1; P < 0.05) and even more during the descent to civilization (83 +/- 17 ml.kg-1.day-1; P < 0.05).

Adult↗
PubMed1996

Role of intelligence tests in speech/language referrals.

This study examined the relation of the WISC-R Verbal IQ with measures of oral and written language among 190 students referred to a private educational clinic over a 5-yr. period. Correlations of Verbal IQ with scores on measures of oral language, written language, receptive language, reading comprehension, and basic reading skills were calculated for the total sample and by Grades 1-3, 4-7, and 8-11. Standard regression coefficients were used to estimate the proportion of variance explained by these five measures. Significant correlations were found for Verbal IQ with the measures, ranging from .36 (Basic Reading Skills) to .69 (Receptive Vocabulary). Multiple regression indicated that 59% of the variance was explained by the five measures and that three--Oral Language, Receptive Vocabulary, and Reading Comprehension--contributed significantly to Verbal IQ. Correlations across grades showed inconsistent differences by grade for Verbal IQ with language variables. Implications for speech-language referral practices are discussed.

Adolescent↗
PubMed1996

[Maternal and fetal retinoid assay. Two case reports of isotretinoin (Roaccutane) exposure].

We report on 2 women who were treated with retinoids (Roaccutan, isotretinoin) during the first trimester of their pregnancies. Therapeutic abortions were carried out. The interest in these case reports lies in the determination of concentration of isotretinoin and its metabolites (4-oxo-isotretinoin, and tretinoin) in foetal tissues, using high performance liquid chromatography. The findings show the significant transplacental passage of isotretinoin, an accumulation of 4-oxo-isotretinoin in the liver, and a low concentration of retinoids in the brain of these foetuses. Contraception must be used with retinoid treatment and for 4 weeks after retinoid withdrawal.

Abortion, Therapeutic↗
PubMed1996

Primary psoas abscess--diagnostic and therapeutic considerations.

OBJECTIVE: To present our experience of the diagnosis and treatment of primary psoas abscess in India. PATIENTS AND METHODS: Between July 1993 and December 1995, five men (aged 24-67 years) presented with suspected primary psoas abscess. All five patients had fever with or without rigors and upper/lower abdominal pain of varying duration (2-6 weeks). RESULTS: The presentation in all patients was conspicuous by the absence of the classical signs of limping and positive psoas symptoms. Computed tomography (CT) was the best method of diagnosis, being accurate in every case. Antibiotics alone (two patients), or in combination with percutaneous aspiration, were curative. CONCLUSIONS: This small series of five patients of primary psoas abscess was remarkable in that all the patients were men and three were elderly. The classical symptom of limping was absent in all. The urologist can be misled by loin pain and irritative lower urinary symptoms in the patients, resulting in a delay in diagnosis and management.

Adult↗
PubMed1996

Reappearance of event-related P3 potential in locked-in syndrome.

In a patient affected by locked-in syndrome, because of a lesion of the caudal-ventral pontine tegment, we recorded event-related potentials (ERPs) to an acoustic odd-ball paradigm. We did not record N2 and P3 components in the 50 days following the acute lesion although the patient was able to understand the task and communicate with blinking. 55 days after the acute lesion, N2 and P3 reappeared on scalp derivations. This findings suggest that brainstem structures are involved in P3 or N2-P3 generation.

Acoustic Stimulation↗
PubMed1996

[The membrane oxygenator].

Researches in blood oxygenation through a membrane, in an extracorporal circuit, with the physiological flow of an adult and an oxygen saturation have led up, by experimental way, to use dissolved oxygen. The membrane is a plastic microporous film coating a strong textile support which constitutes a cylindrical rotor. The rotor micropores are crossed through by a pH 7.4 phosphate buffer aerosol which conveys the oxygen. This aerosol is dropped in the revolving rotor. Venous blood which spreads out on the external surface of the rotor is immediately hematosed in contact with the atmospheric pressure with free release of carbon dioxide without microbubbles formation. The low pressure which prevails in the rotor is maintained only when the membrane is hydrated by the aerosol. To do that, it is enough to maintain the hydratation by a buffer drip: one drop per second can be enough. During the high flow open-heart operation of an adult patient, the curves of physiological constants remain normal. The membrane is perfectly stable during the period it is used. In France, according to François de Gaudard d'Allaines, this equipment has allowed "the adult first open-heart operation with extracorporal circulation" (1958). About sixty operations have been realized under the responsibility of François de Gaudard d'Allaines and myself.

Extracorporeal Circulation↗
PubMed1995

Bayesian approaches to random-effects meta-analysis: a comparative study.

Current methods for meta-analysis still leave a number of unresolved issues, such as the choice between fixed- and random-effects models, the choice of population distribution in a random-effects analysis, the treatment of small studies and extreme results, and incorporation of study-specific covariates. We describe how a full Bayesian analysis can deal with these and other issues in a natural way, illustrated by a recent published example that displays a number of problems. Such analyses are now generally available using the BUGS implementation of Markov chain Monte Carlo numerical integration techniques. Appropriate proper prior distributions are derived, and sensitivity analysis to a variety of prior assumptions carried out. Current methods are briefly summarized and compared to the full Bayes analysis.

Bayes Theorem↗
PubMed1995

Non-dominant dorsal-prefrontal activation during chess problem solution evidenced by single photon emission computerized tomography (SPECT).

Expert chess players can recall meaningful chess positions with extraordinary precision in comparison with inexperienced players. We hypothesized, therefore, that their mental performance during chess deliberation could be an appropriate target for single photon emission computerized tomography (SPECT) studies. We studied cerebral activation with 1110 MBq 99mTc-Bicisate SPECT in five expert male chess players during mental solution of a complex chess problem. Region of interest (ROI) analysis, in comparison with average weighted cerebellar counts, showed activation by 10% or more, of the non dominant prefrontal area (right in four dominant right handed players, left in one dominant left handed player) and by 2-6% in the non-dominant middle temporal areas. Maximum variability of ROI analysis versus cerebellar counts in test/retest evaluation is in our laboratory, as in others, 1.5%. Our results are in agreement with neuropsychological studies suggesting that the non-dominant hemisphere is specialized for chess skill, and show that non-dominant prefrontal and temporal lobe activation during chess deliberation can be detected by SPECT.

Adult↗
PubMed1995

Structural basis of antibody cross-reactivity: solution conformation of an immunogenic peptide fragment containing both T and B epitopes.

A synthetic octadecapeptide with the amino acid sequence of residues 23-40 of toxin alpha from Naja nigricollis, cyclized with a disulfide bridge between residues 23 and 40, induces antibodies that cross-react with toxin alpha. We report a structural analysis of this peptide in aqueous solution using NMR spectroscopy and molecular modeling. Structures compatible with the 151 obtained NMR distance restraints were generated using a random simulated annealing protocol followed by restrained high-temperature dynamics and energy minimization. The generated structures are compared with that of the corresponding sequence in the native toxin. The two stretches 23-28 and 37-40 adopt a canonical beta-strand structure in the toxin but are disordered in the peptide. The region 28-36 is ordered in both the peptide and the toxin. Residues 28-30 and 34-36 adopt beta-strand structures in the toxin but loop structures in the peptide. Residues 30-33 form a reverse turn in both the peptide and the toxin. Residues Val-27, Trp-28, Ile-35, and Ile-36 form a hydrophobic cluster. The similar, reverse-turn fold of residues 30-33 in the peptide and the toxin may be associated with the immunogenic cross-reactivity.

Amino Acid Sequence↗
PubMed1995

Analysis of cysteine mutations on the transmembrane protein of Moloney murine leukemia virus.

Earlier studies of murine leukemia viruses (MuLVs) have reported that a percentage of surface protein (SU) remains covalently associated with transmembrane protein (TM) through formation of disulfide bonds. Among MuLVs, there are three conserved cysteine residues within the extracellular domain of TM. These cysteine residues were substituted individually with serines to define their function and possible role in disulfide bonding with SU. Using oligonucleotide-directed mutagenesis, seven mutant constructs were generated with individual as well as multiple cysteine mutations. Transient transfection of all seven cysteine mutations resulted in nonviable virus. Analysis of intracellular proteins of producer mutant cell lines have demonstrated that precursor envelope protein (gPr80env; SU/TM) is being synthesized, but transport and processing of gPr80env is blocked in the endoplasmic reticulum. Two independent reversions of one cysteine mutation have been isolated and characterized.

Amino Acid Sequence↗
PubMed1995

Frequent homozygous deletions of D13S218 on 13q14 in B-cell chronic lymphocytic leukemia independent of disease stage and retinoblastoma gene inactivation.

A correlative study has been performed to delineate further the role of the Rb gene in the disease B-cell chronic lymphocytic leukemia (B-CLL). First, we examined DNAs from B cells from 140 B-CLL patients representing all Rai stages of disease for the loss of 13q14 using two microsatellite markers mapping distal to the Rb locus. Loss of heterozygosity (LOH) of D13S133 was infrequent, occurring in 5 of 140 (4%) patients. The frequency for LOH of D13S218 was 33 of 140 (24%) samples and was independent of Rai stage of disease. Rb protein was detected in 19 of 23 (83%) samples. Of 4 patients lacking detectable Rb gene expression, only one showed LOH of D13S218. Rb protein levels varied from undetectable to high in samples with or without LOH for D13S218, and the levels were also independent of Rai stage of disease. Our findings support the role of DBM on 13q14, rather than Rb, as the candidate tumor suppressor gene that is frequently targeted for deletion in B-CLL. In addition, the data suggest that other mechanism(s) contribute to altered Rb expression detected in one-fourth of B-CLL B-cells.

Chromosome Deletion↗
PubMed1995

Targeting of the 67-kDa isoform of glutamic acid decarboxylase to intracellular organelles is mediated by its interaction with the NH2-terminal region of the 65-kDa isoform of glutamic acid decarboxylase.

The two isoforms of glutamic acid decarboxylase (GAD), GAD67 and GAD65, synthesize the neurotransmitter gamma-aminobutyric acid in neurons and pancreatic beta-cells. Previous studies suggest that GAD67 is a soluble cytosolic protein, whereas GAD65 is membrane-associated. Here, we study the intracellular distribution of GAD67 in neurons, pancreatic beta-cells, and fibroblasts transfected either with GAD65 and GAD67 together or with GAD67 alone. Neuronal GAD67 is partially recovered with GAD65 in membrane-containing pellet fractions and Triton X-114 detergent phases. The two proteins co-immunoprecipitate from extracts of brain and GAD65-GAD67 co-transfected fibroblasts, but not when extracts of GAD65 and GAD67 transfected fibroblasts were mixed and used as a starting material for immunoprecipitation. GAD67 is concentrated in the Golgi complex region in GAD65-GAD67 co-transfected fibroblasts, but not in fibroblasts transfected with GAD67 alone. A pool of neuronal GAD67 co-localizes with GAD65 in the Golgi complex region and in many synapses. The two proteins also co-localize in the perinuclear region of some pancreatic beta-cells. GAD67 interacts with the NH2-terminal region of GAD65, even in the absence of palmitoylation of this region of GAD65. Taken together, our results indicate that GAD65-GAD67 association occurs in vivo and is required for the targeting of GAD67 to membranes.

Animals↗