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Biomedical subjects

P Thomas

Publications and source records attributed to P Thomas.

At least 307 records · Page 17Linked to original sources
PubMed1999

Clostridium methoxybenzovorans sp. nov., a new aromatic o-demethylating homoacetogen from an olive mill wastewater treatment digester.

A strictly anaerobic, spore-forming bacterium (3.0-5.0 x 0.4-0.8 microns), designated strain SR3T (T = type strain), which stained Gram-positive and possessed a Gram-positive type cell wall was isolated from a methanogenic pilot-scale digester fed with olive mill wastewater (Sfax, Tunisia). It utilized a number of carbohydrates (glucose, fructose, sorbose, galactose, myo-inositol, sucrose, lactose, cellobiose), organic compounds (lactate, betaine, sarcosine, dimethylglycine, methanethiol, dimethylsulfide), alcohol (methanol) and all methoxylated aromatic compounds only in the presence of yeast extract (0.1%). The end products from carbohydrate fermentation were H2, CO2, formate, acetate and ethanol, that from lactate was methanol, those from methoxylated aromatics were acetate and butyrate, and that from betaine, sarcosine, dimethylglycine, methanethiol and dimethylsulfide was only acetate. Strain SR3T was non-motile, had a G+C content of 44 mol% and grew optimally at 37 degrees C and pH 7.4 on a glucose-containing medium. Phylogenetically, the closest relatives of strain SR3T were the non-methoxylated aromatic-degrading Clostridium xylanolyticum, Clostridium aerotolerans, Clostridium sphenoides and Clostridium celerecrescens (mean similarity of 98%). On the basis of the phenotypic, genotypic and phylogenetic characteristics of the isolate, it is proposed to designate strain SR3T as Clostridium methoxybenzovorans sp. nov. The type strain is SR3T (= DSM 12182T).

Bacterial Typing Techniques↗
PubMed1999

Aminomonas paucivorans gen. nov., sp. nov., a mesophilic, anaerobic, amino-acid-utilizing bacterium.

A novel, asaccharolytic, amino-acid-degrading bacterium, designated strain GLU-3T, was isolated from an anaerobic lagoon of a dairy wastewater treatment plant. Strain GLU-3T stained Gram-negative and was an obligately anaerobic, non-spore-forming, slightly curved, rod-shaped bacterium (0.3 x 4.0-6.0 microns) which existed singly or in pairs. The DNA G+C content was 43 mol%. Optimum growth occurred at 35 degrees C and pH 7.5 on arginine with a generation time of 16 h. Good growth was obtained on arginine, histidine, threonine and glycine. Acetate was the end-product formed from all these substrates, but in addition, a trace of formate was detected from arginine and histidine, and ornithine was produced from arginine. Strain GLU-3T grew slowly on glutamate and produced acetate, carbon dioxide, formate, hydrogen and traces of propionate as the end-products. In syntrophic association with Methanobacterium formicicum, strain GLU-3T oxidized arginine, histidine and glutamate to give propionate as the major product; acetate, carbon dioxide and methane were also produced. Strain GLU-3T did not degrade alanine and the branched-chain amino acids valine, leucine and isoleucine either in pure culture or in association with M. formicicum. The nearest phylogenetic relative of strain GLU-3T was the thermophile Selenomonas acidaminovorans (similarity value of 89.5%). As strain GLU-3T is phylogenetically, physiologically and genotypically different from other amino-acid-degrading genera, it is proposed that it should be designated a new species of a new genus Aminomonas paucivorans gen. nov., sp. nov. (DSM 12260T).

Amino Acids↗
PubMed1999

Sporobacterium olearium gen. nov., sp. nov., a new methanethiol-producing bacterium that degrades aromatic compounds, isolated from an olive mill wastewater treatment digester.

A strictly chemo-organotrophic, anaerobic bacterium was isolated from an olive mill wastewater treatment digester on syringate and designated strain SR1T. The cells were slightly curved rods, stained Gram-positive and possessed terminal spores. Strain SR1T utilized crotonate, methanol and a wide range of aromatic compounds including 3,4,5-trimethoxybenzoate (TMB), 3,4,5-trimethoxycinnamate (TMC), syringate, 3,4,5-trimethoxyphenylacetate (TMPA), 3,4,5-trimethoxyphenylpropionate (TMPP), ferulate, sinapate, vanillate, 3,4-dimethoxybenzoate, 2,3-dimethoxybenzoate, gallate, 2,4,6-trihydroxybenzoate (THB), pyrogallol, phloroglucinol and quercetin as carbon and energy sources. Acetate and butyrate were produced from aromatic compounds, methanol and crotonate whereas methanethiol (MT) was produced from methoxylated aromatic compounds and methanol. Strain SR1T had a G + C content of 38 mol% and grew optimally between 37 and 40 degrees C at pH 7.2 on a crotonate-containing medium. Phylogenetically, strain SR1T was a member of cluster XIVa of the Clostridiales group and shared a sequence similarity of 90% with Clostridum aminovalericum and Eubacterium fissicatena. Consequently, its precise neighbourliness to any one of them depended on the selection of strains of the cluster. On the basis of the phylogenetic and phenotypic evidence presented in this paper, the designation of strain SR1T as Sporobacterium olearium gen. nov., sp. nov. is proposed. The type strain is SR1T (= DSM 12504T).

Acetates↗
PubMed1999

Lack of association between juvenile myoclonic epilepsy and HLA-DR13.

PURPOSE: We sought to replicate and extend a previously reported positive association between juvenile myoclonic epilepsy and HLA-DR13. METHODS: Ninety-three subjects with juvenile myoclonic epilepsy and 93 normal blood donors, entirely of white origin with their families mostly of French extraction, underwent DNA-based HLA-DR13 and DQB6 typing. RESULTS: None of the investigated alleles or combination of alleles (DRB1*1301-DQB1*0603 or DRB1*1302-DQB1*0604) showed a significant difference between patients and controls. CONCLUSIONS: Unlike previously reported positive association, in this population, there is no evidence that susceptibility to juvenile myoclonic epilepsy is associated with HLA-DR13.

Alleles↗
PubMed1999

GABA exerts stimulatory and inhibitory influences on gonadotropin II secretion in the Atlantic croaker (Micropogonias undulatus).

Possible involvement of gamma-aminobutyric acid (GABA) in the control of gonadotropin II (GTH II) secretion was investigated during different phases of the seasonal gonadal cycle of the Atlantic croaker (Micropogonias undulatus). Intraperitoneal administration of GABA (100 microgram/g) elicited a significant increase in plasma GTH II levels in croaker with regressed or pre-recrudescence phase gonads, whereas it did not significantly affect GTH II levels during the early- to mid-recrudescence phase of the gonadal cycle in this species. On the other hand, GABA induced a dose-related inhibition of GTH II secretion in fish with fully recrudesced gonads. Similar opposite changes in GTH II levels were observed when croaker with regressed and fully recrudesced gonads were injected with the GABA transaminase inhibitor, gamma-vinyl GABA (10 and 100 microgram/g). This suggests an involvement of endogenous GABA in the control of GTH II secretion. GABA (1-100 microM) did not significantly alter GTH II release from pituitary fragments from regressed or fully recrudesced fish incubated in vitro, suggesting the lack of a major direct influence at the pituitary level. Muscimol (GABAA receptor agonist, 1 microgram/g) treatment mimicked both the stimulatory and inhibitory effects of GABA, whereas injection of baclofen (GABAB receptor agonist, 1 microgram/g) had no significant effect on basal or a gonadotropin-releasing hormone (GnRH) analog-induced GTH II secretion. Pretreatment of fish with bicuculline (1 microgram/g), a GABAA antagonist, completely blocked the stimulatory influence of GABA on GTH II secretion in croaker with regressed gonads and partially blocked the inhibitory effect in individuals with fully recrudesced gonads. The results demonstrate that GABA exerts opposite influences on GTH II secretion at two different stages of the gonadal cycle of croaker, and acts primarily via GABAA type receptors. Thus, GABAergic pathways may be important in mediating seasonal influences on GTH II secretion in this species.

Animals↗
PubMed1999

Haemoptysis after breath-hold diving.

Pulmonary oedema has been described in swimmers and self-contained underwater breathing apparatus (Scuba) divers. This study reports three cases of haemoptysis secondary to alveolar haemorrhage in breath-hold divers. Contributory factors, such as haemodynamic modifications secondary to immersion, cold exposure, exercise and exposure to an increase in ambient pressure, could explain this type of accident. Furthermore, these divers had taken aspirin, which may have aggravated the bleeding.

Adult↗
PubMed1999

Pulmonary arteriovenous malformations: lung transplantation as a therapeutic option.

Multiple pulmonary arteriovenous malformations (PAVM) constitute an uncommon cause of respiratory disability. They may lead to severe hypoxaemia via right-to-left shunts and are sources of substantial mortality and morbidity. Conservative surgical resection has been proposed as the treatment of choice. More recently, percutaneous balloon or coil embolization of the feeding vessels offered an efficacious and safe alternative therapy for patients whose fistulas are too numerous to excise. This study reports an unusual case of respiratory disability in a patient with multiple and microscopic pulmonary arteriovenous malformations who failed to respond to embolotherapy and who received a double lung transplantation with good initial outcome.

Adult↗
PubMed1999

Role of adjuvant chemotherapy in the treatment of surgically resected pediatric nonrhabdomyosarcomatous soft tissue sarcomas: A Pediatric Oncology Group Study.

PURPOSE: To prospectively study the value of adjuvant chemotherapy in pediatric patients with surgically resected nonrhabdomyosarcomatous soft tissue sarcomas (NRSTS). PATIENTS AND METHODS: From June 1986 to May 1992, after complete surgical resection (+/-radiotherapy) of their NRSTS, 81 eligible patients either received adjuvant chemotherapy comprising vincristine, dactinomycin, cyclophosphamide, and doxorubicin or were observed. Only 30 patients accepted randomization, and 15 were assigned to each regimen. Of the remaining 51 patients, 19 elected adjuvant chemotherapy and 32 elected observation. RESULTS: Patients were predominantly male, and 69% of all patients were white. The median age at diagnosis was 12.3 years (range, 9.2 to 20.7 years). For the 81 eligible patients, the 5-year overall survival estimate was 84.5% +/- 4.4% and event-free survival was 72.2% +/- 5.4%. Among randomized patients, the 5-year estimated overall survival rate was 93.3% +/- 7%, and the event-free survival rate was 86.7% +/- 9.5% for the observation group, compared with 69.2% +/- 13% and 40.7% +/- 14%, respectively, for those who received chemotherapy. The significantly worse outcome of patients who received adjuvant chemotherapy disappeared when survival was stratified by tumor grade. Among all patients, a grade 3 lesion conferred a significant disadvantage with respect to event-free survival (P =.0001). CONCLUSION: The administration of adjuvant chemotherapy according to the schedule and dosages used in our trial did not improve the outcome of children with resected NRSTS. In this study, tumor grade was the most important predictor of clinical outcome in patients with resected NRSTS, and this factor should be incorporated into the stratification of patients in future trials.

Adolescent↗
PubMed1999

Characterization of two nuclear androgen receptors in Atlantic croaker: comparison of their biochemical properties and binding specificities.

Two distinct androgen receptors (ARs) with different characteristics were identified in the brain and ovary of Atlantic croaker, Micropogonias undulatus. A nuclear AR, AR1, was identified in the brain that had high affinity binding sites for testosterone (T; Kd, 1.1 +/- 0.15 nM; binding capacity, 1.4 +/- 0.14 pmol/g tissue; n = 16). A second nuclear AR, AR2, was found in the ovary that had high affinity binding sites for 5alpha-dihydrotestosterone (DHT; Kd, 0.62 +/- 0.1 nM; binding capacity, 0.38 +/- 0.06 pmol/g tissue; n = 14). AR2 has physiochemical properties similar to those of other vertebrate ARs. AR2 has high affinity binding for a broad spectrum of natural and synthetic androgens, including 17alpha-methyl-5alpha-dihydrotestosterone, which has a relative binding affinity of DHT = 100% > T > mibolerone > 11-ketotestosterone = 16%, a rapid association (t1/2, 44 min) and a slow dissociation (t1/2, 45 h) rate, as well as specific binding to purified DNA. The cytosolic AR2 interacts with heat shock proteins in a manner similar to other steroid receptors, as sodium molybdate stabilizes the receptor, and it has a 7.4-7.8S sedimentation coefficient in a 5-20% sucrose gradient. In contrast, AR1 is highly specific for only a few androgens, with T = 100% relative binding affinity >> DHT >> 11-ketotestosterone > mibolerone > 17alpha-methyl-5alpha-dihydrotestosterone = 0, has rapid association (t1/2, 15 min) and dissociation (t1/2, 2.6 +/- 0.7 h) rates, and has specific binding to purified DNA upon heat activation. The cytosolic binding component sediments at 5.6-5.7S in a 5-20% sucrose gradient and is not affected by sodium molybdate, which suggests that AR1 does not interact with heat shock proteins in the usual manner. This is the first report of the presence of two different nuclear ARs displaying markedly different steroid binding specificities within a single vertebrate species.

Animals↗
PubMed1999

Pesticides interfere with the nongenomic action of a progestogen on meiotic maturation by binding to its plasma membrane receptor on fish oocytes.

Although many environmental contaminants disrupt endocrine function by binding to nuclear steroid receptors, it is not known whether they are capable of binding to steroid membrane receptors and interfering with nongenomic actions of steroids. The binding of several organochlorine pesticides to the plasma membrane receptor for the maturation-inducing steroid, 17,20beta,21-trihydroxy-4-pregnen-3-one (20beta-S), in the ovaries of spotted seatrout (Cynoscion nebulosus) was investigated in in vitro competition assays. Kepone and o,p'-DDD were competitive inhibitors of 20beta-S binding and caused concentration-dependent displacement of [3H]-20beta-S from its receptor site over the range of 10(-4) to 10(-6) or 10(-7) M, whereas several other pesticides had lower affinities for the receptor. Interference with the nongenomic actions of 20beta-S on final meiotic maturation of spotted seatrout oocytes (final oocyte maturation, FOM) was examined in an in vitro bioassay. A concentration-dependent inhibition of FOM in response to 20beta-S was observed after 5 min and 12 h exposure to the same range of Kepone and o,p'-DDD concentrations (10(-4) to 10(-6) or 10(-7) M). The close correspondence between competitive binding of the two pesticides to the 20beta-S membrane receptor and their inhibition of 20beta-S induced FOM suggests a mechanism of endocrine disruption mediated by binding to a steroid membrane receptor and antagonism of a nongenomic steroid action.

Animals↗
PubMed1999

Dialogical engagement with voices: a single case study.

This paper raises the possibility that a dialogical, or discursive, model of human experience may be useful in helping someone who experiences verbal hallucinations. The model regards verbal hallucinations as a variety of inner speech with dialogical properties. The explication of these properties in the context of a personal narrative allowed the individual to engage in dialogue with the voices, through the medium of a new, supportive and positive voice. This process made it possible to introduce moral responses to distressing and potentially dangerous imperative verbal hallucinations, through the mediation of the new voice. Her dialogical engagement with this voice enabled her to deal effectively with troublesome voices, and was a powerful source of self-esteem. We briefly present the theoretical perspective underlying this approach, and compare and contrast the approach with cognitive-behavioural techniques.

Cognitive Behavioral Therapy↗
PubMed1999

Improved high altitude hypoxic tolerance and amelioration of anorexia and hypophagia in rats on oral glutamate supplementation.

BACKGROUND: The objective of this study is to evaluate the efficacy of oral glutamic acid supplementation in promoting hypoxic tolerance. METHODS: The experiments were conducted in albino rats by exposing them to three levels of hypoxia in a simulated environment for varying periods of time. The parameters studied include: gasping time at 35,000 ft (10,668 m), food and water intake, and heart to body weight (b.w.) ratio at 25,000 ft (7620 m), tolerance to composite stress at 15,000 ft (4572 m) and biodistribution of glutamate (glu). RESULTS: Supplementation of Glu (27 mg x kg(-1) b.w.) as glutamic acid dissolved in normal saline resulted in 4.8 times enhanced hypoxic tolerance (time taken for appearance of first gasp), 23% body weight gain and 24% increase in food consumption over control during hypoxia. When animals were subjected to composite stress of cold, hypoxia and restraint (CHR), the Glu fed animals showed higher resistance to fall in rectal temperature than the control group. Hypoxia significantly enhanced heart to body weight ratio compared with control, and Glu supplementation reduced and brought it down to that of control. CONCLUSION: The study reveals that Glu in optimal doses may be a conditionally essential amino acid resulting in enhanced tolerance to hypoxia and cold.

Administration, Oral↗
PubMed1999

[Long-term survival of a patient with melanoma with late recurrence of pulmonary metastasis treated by repeat surgery].

We report the case of a young woman initially treated with surgery, radiotherapy, chemotherapy and BCG therapy for stage II malignant melanoma involving the limbs. Considering that the risk of metastasis is usually maximal between 2 and 5 years after initial treatment, metastatic dissemination of this melanoma was rather unusual. Metastases were observed locally, regionally, and in the lungs 8, 10 and 12 years respectively after the primary diagnosis. Repeat surgery was performed to resect pulmonary nodules. Such surgery is possible in less than 10% of the cases of metastatic melanoma. Our patient has survived without relapse for 21 years after the initial diagnosis and 8 years after the last tumor excision. Recurrent pulmonary metastasis without extrapulmonary dissemination would suggest the tumor cell population was composed of a particular metastatic phenotype.

Aged↗