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J Thomas

Publications and source records attributed to J Thomas.

At least 361 records · Page 20Linked to original sources
PubMed1995

[Urinary calculi, consisting of dehydrated calcium phosphate. Clinical, biological, radiologic aspects, clinical course and management].

Seventeen cases of urinary calculi analyzed by infrared spectrophotometry were found to be composed entirely or nearly entirely of bihydrated calcium hydrophosphate. The observations are summarized here. This type of stone occurs with a frequency of about 1% (0.85% in our experience) of all urinary calculi, predominantly in men (14 of our 17 cases). Diagnosis is based on the physical and chemical analysis of the stone and on infrared spectrophotometry. Most of these stones are pure or nearly pure compounds. The macroscopic aspect of the stones or fragments of stones can guide diagnosis. These stones are cream coloured stones with a smooth regular outer surface. Broken fragments show the same cream colour, sometimes with strips radiating from the centre of the fracture surface. Radiologically, these stones are homogeneously radio-opaque, often oval-shaped with a regular outline. Blood tests can demonstrate suspected or proven hyperparathyroidism (4 out of 10 cases in our 17 observations) with hypercalcemia, hypophosphatemia and hypercalciuria. Complementary examinations may be needed to search for a parathyroid adenoma. With or without hyperparathyroidism, 24-h urinalysis usually shows hypercalciuria up to ro over 500 to 600 mg/24 h. Crystallization usually occurs in the upper urinary tract, in the bladder or in indwelling catheters. These stones are extremely hard and are difficult to break in vitro. To be successful, lithotripsy requires prolonged treatment: up to 3000 to 6000 shockwaves at 22-23 kv with the Dornier apparatus. Despite the notion of hypercalciuria, the pathogenesis of bihydrated calcium hydrophosphate calculi remains to be elucidated.

Adult↗
PubMed1994

Continuous postcolumn detection of underivatized polysaccharides in high-performance liquid chromatography by reaction with permanganate.

We describe a continuous postcolumn reaction system for colorimetric detection of carbohydrates suitable for use with both preparative and analytical HPLC separations. A fraction of the effluent from the column is mixed via a T-junction with a 0.02% solution of potassium permanganate in 3 M sulfuric acid. The mixture then passes through a reaction coil heated to 100 degrees C, and its absorbance at 525 nm is continuously monitored. Bleaching of the permanganate is proportional to the sugar concentration. The major advantages of the detection system are its mass rather than molar sensitivity and insensitivity to changes in nonoxidizable buffer concentrations. As little as 0.1 micrograms of sugar can be detected. These features make the system suitable for detection, with high sensitivity, of polysaccharides using gradient elution from ion-exchange columns.

Chromatography, High Pressure Liquid↗
PubMed1994

A 6-hydroxydopamine-induced selective parkinsonian rat model: further biochemical and behavioral characterization.

The main focus of the present study was to define the rotational response of 6-hydroxydopamine-lesioned rats to dopaminergic agonists to separate the partially lesioned rats from those having complete substantia nigra (SN) and ventral tegmental area (VTA) lesions. Animals were challenged by amphetamine and L-DOPA for 10 consecutive weeks. There was a correlation between rotational behavior and extent of midbrain cell loss. Rats with complete SN and < 40% VTA lesion turned more than 5 times/min after amphetamine administration, but not after L-DOPA; animals with complete SN and 40-80% VTA lesions turned vigorously following amphetamine and began turning after L-DOPA administration. Rats with complete SN and VTA lesions turned less after amphetamine than the other two groups, while their turning after L-DOPA administration increased. Extracellular dopamine (DA) measured by microdialysis, intracellular DA measured by postmortem tissue punches, and tyrosine hydroxylase-immunoreactive cell count in SN and VTA were also evaluated. It appears that the dopaminergic cells in the lateral VTA affect DA concentration in the medial caudate nucleus. In the nucleus accumbens of the lesioned side, DA release and metabolism substantially increased with the larger VTA lesion. Dopamine turnover rate in the caudate was also higher in the group with < 40% VTA lesion.

Amphetamine↗
PubMed1994

The effects of phonetic similarity and list length on children's sound categorization performance.

Three experiments investigating children's performance on tests of sound categorization are reported. In two experiments, the children had to decide which was the "odd one out" in a sequence of three, four, and five words. In each case the "oddity" judgement required selecting the word which differed in its final consonant, producing a different rime segment. The odd word differed either by one phonetic feature (voice or place) or by both voice and place, from the others in the sequence. Oddity judgements were easier when the odd word was phonetically dissimilar to the background items but, contrary to expectation, performance did not decline as list length increased. Experiment 3 extended these findings by showing that place-only changes were more difficult than voice-only changes. Sound categorization performance correlated with memory span for words, but memory span did not make an independent contribution to sound categorization once age and reading skills had been controlled. The experiments show that the sound categorization task taps individual differences in speech perception mechanisms but that memory load is less crucial to this task than has often been supposed.

Age Factors↗
PubMed1994

Bioactive chromenes from Rhyncholacis penicillata.

Investigation of the aerial parts of Rhyncholacis penicillata afforded the new chromenes, 7-hydroxy-6-(3-methylbutyryl)-5-oxymethyl-chromene (rhynchonin A) and 7-hydroxy-6-(2-methylbutyryl)-6-oxymethylchromene (rhynchonin B). Structures were elucidated by spectroscopic methods and independent synthesis. Rhynchonin A showed broad insecticidal, acaricidal and nematicidal potency including strong biological activity against Heliothis zea.

Animals↗
PubMed1994

Obstacles to hepatitis B vaccine uptake by health care staff.

OBJECTIVES: (1) To identify reasons for non-uptake of hepatitis B vaccine by health care staff; (2) to determine whether fully vaccinated staff are aware of the need to consider booster vaccinations in the future. DESIGN: Semi-structured anonymous questionnaire survey of health care staff. SETTING: Croydon health district, south London. SUBJECTS: 462 health care staff. RESULTS: 300 staff (65%) responded. The reasons given by staff for non-uptake included fear of side-effects or injections, misconceptions about hepatitis B transmission, the alternative use of homeopathic vaccine, pressure of work, difficulties in arranging vaccination, forgetfulness, and 'inertia'. Of the 54 unvaccinated staff, 55.6% believed themselves to be at high risk of contracting hepatitis B as a result of their occupation; 33% of 202 fully vaccinated staff were unaware of the use of booster doses of vaccine to maintain long-term immunity. CONCLUSIONS: The level of awareness and understanding about hepatitis B vaccination of any group of health care staff should not be assumed. A number of specific educational and organisational issues need to be addressed when implementing staff vaccination programmes. Without the use of automatic call-recall systems the long-term success of staff hepatitis B vaccination programmes may be in doubt.

Adult↗
PubMed1994

General practice awareness of notifiable infectious diseases.

The Acheson Report concluded that the process of infectious disease notification in England and Wales was unsatisfactory and recommended that it should be reviewed. However, the success of any notification system will depend on the knowledge and motivation of general practitioners, who are responsible for a large proportion of infectious disease notifications. A district-wide telephone survey was conducted in Croydon among general practitioners to assess the level of awareness of which diseases are on the statutory notification list. Respondents' opinions were also sought on the composition of the present list. Results indicated that a generally high level of awareness contrasted with a relative paucity in knowledge of certain of the more common diseases. Differences in knowledge were not associated with the sex, the length of time since the doctor qualified or the number of partners in the particular practice. Motivation may be a particularly important factor underlying the present incompleteness of notifications. A large proportion of doctors stated that legionellosis, AIDS, brucellosis and listeriosis merited statutory notification.

Communicable Disease Control↗
PubMed1994

Testosterone levels during systemic and inhaled corticosteroid therapy.

Testosterone has importance both as a sex hormone and as an anabolic steroid promoting bone formation. Osteoporosis is associated with both hypogonadism and corticosteroid therapy. Testosterone levels are reduced by long term prednisolone treatment. Although high dose inhaled corticosteroid therapy may cause a variety of systemic effects including adrenal suppression, dermal thinning and a reduction in total bone calcium, its effect on testosterone levels is not known. Testosterone, luteinizing hormone, follicle stimulating hormone and sex hormone binding globulin were therefore measured in 35 male patients with respiratory disease attending an outpatient clinic (median age 58, range 21-75 years). They were grouped according to steroid therapy and compared with 19 age matched controls. Mean (SD) testosterone levels were 33% lower in 12 men on long term oral prednisolone [14.5 (6.0) nmol 1-1] than in controls [21.7 (6.3) nmol 1-1], but were not significantly reduced in 10 patients on low dose inhaled beclomethasone [200-800 micrograms day-1: 19.7 (3.7)] nor in 13 men taking high dose inhaled beclomethasone [1500-2,250 micrograms day-1: 17.9 (5.6)]. Levels of luteinizing hormone, follicle stimulating hormone and sex hormone binding globulin were similar in all four groups. These cross sectional data confirm that long term systemic corticosteroid therapy reduces testosterone levels. However, testosterone was reduced by only 18% (NS) by long term inhaled corticosteroids. Other mechanisms to explain the disordered bone metabolism should now be explored.

Administration, Inhalation↗
PubMed1994

Preliminary results of the EORTC-GPMC controlled clinical trial H7 in early-stage Hodgkin's disease. EORTC Lymphoma Cooperative Group. Groupe Pierre-et-Marie-Curie.

In this phase III trial, 770 patients with clinical stage I-II Hodgkin's disease (HD) have been enrolled since November 1988. Preliminary results are given for the 605 (79%) patients who have completed their initial therapy. Patients were grouped according to 6 pretreatment prognostic characteristics. In the very favourable (VF) group, treatment consisted of mantle field alone. In the favourable (F) group, patients were randomized to either subtotal nodal irradiation (STNI), or 6 cycles of EBVP (epirubicin, bleomycin, vinblastine, prednisone) followed by involved-field irradiation (IF-RT). Unfavourable (U) patients were randomized to either 6 cycles of EBVP plus IF-RT, or to 6 cycles of MOPP/ABV hybrid plus IF-RT. Of the 35 VF patients, none have progressed during radiotherapy. Four patients relapsed and were salvaged. Three-year failure-free survival (FFS) was 82%; overall survival (OS) was 100%. Of the 254 F patients, 130 were treated with STNI and 124 with EBVP plus IF-RT. At 3 years, FFS rates were 81% (1 progression, 14 relapses) and 79% (5 progressions, 8 relapses), respectively. Corresponding OS rates were 99% and 100%. Of the 316 U patients, 160 received EBVP and 156 MOPP/ABV. At 3 years, FFS rates were 72% (18 progressions, 20 relapses) and 88% (7 progressions, 6 relapses), respectively (p < 0.001). Although OS rates were identical (92%), the entry in the U-EBVP arm was stopped in November 1992. We conclude that a treatment strategy based on prognostic factors allows the use of less aggressive treatment in favourable patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

EORTC study of non-Hodgkin's lymphoma: phase III study comparing CHVmP-VB and ProMACE-MOPP in patients with stage II, III, and IV intermediate- and high-grade lymphoma.

In the EORTC lymphoma cooperative group, a randomized phase III study was done for patients with stage II, III, IV intermediate- and high-grade lymphoma. Eight courses of CHVmP-VB were compared to eight courses of ProMACE-MOPP. Response was evaluated after 8 courses. Of 430 patients entered, 346 were eligible for this first analysis. Additional radiotherapy was given at initial large masses or residual disease after three courses. Response rate was higher in the CHVmP-VB arm in comparison to the ProMACE-MOPP arm, 82% vs. 65% (p < 0.0005). In the ProMACE-MOPP arm, treatment had to be interrupted because of patient refusal in 7% of the patients. So far there has been no significant difference in freedom from progression at 5 years (49% vs. 47%), relapse-free survival (59% vs. 59%), or overall survival (55% vs. 49%). Patients with early response at 4 courses showed no better RFS in comparison with late responders between 4 and 8 courses. The International Index, based on age, stage, SLDH, performance status, and number of extranodal localizations showed a good prognostic significance in this series of patients.

Adult↗
PubMed1994

New approaches to achieving dietary change.

Current approaches to achieving dietary change are reviewed. The more successful strategies are those that are tailored to the individual and his or her situation and readiness for change, supported when possible by broader social and environmental changes. Some methods of reducing dietary fat intake are better accepted and maintained than others; an emphasis on these may be helpful.

Diet, Fat-Restricted↗
PubMed1994

Exercise testing without interruption of medication for refining the selection of mildly symptomatic patients for prognostic coronary angiography.

OBJECTIVE: To examine how exercise testing on background medical treatment affects the ability of the test to predict prognostically important patterns of coronary anatomy in patients with a high clinical probability of coronary artery disease but who are well controlled on medication. DESIGN: Prospective study. SETTING: Regional cardiothoracic centre and referring district general hospital. PATIENTS: 84 patients with a history of typical angina or definite myocardial infarction and mild symptoms who had been placed on the waiting list for prognostic angiography. INTERVENTION: Maximal exercise electrocardiography and radionuclide ventriculography performed off and on medication, followed by angiography within three months. MAIN OUTCOME MEASURE: Prognostically important coronary artery disease for which early surgery might be recommended purely on prognostic grounds, irrespective of symptoms. RESULTS: Coronary artery disease was present in 71/84 (85%) patients; in 28/84 (33%) patients this was prognostically important. When the result was strongly positive, the predictive accuracy for prognostically important disease was 0.46 off and 0.62 on medication for the exercise electrocardiogram and 0.71 off and 0.82 on medication for exercise radionuclide ventriculography. The likelihood ratio was 1.00 off and 1.36 on medication for exercise electrocardiography and 2.54 off and 10.5 on medication for exercise radionuclide ventriculography. In stepwise logistic regression, the test identified as the strongest predictor of prognostically important disease was exercise radionuclide ventriculography on medication for which the improvement chi 2 was 28 (p < 0.0001). With the regression model, the probability of important disease is 92% if exercise radionuclide ventriculography on medication is at least strongly positive, compared with 16% if the result is normal or just positive. CONCLUSION: In patients likely to have coronary disease, exercise testing should be performed without interruption of medication to optimise its ability to identify those with prognostically important disease, and to help to avoid unnecessary or premature angiography in those who are well controlled on medical treatment.

Adult↗
PubMed1994

Thoracoscopic ganglionectomy for hyperhidrosis.

Thoracoscopic sympathectomy for the treatment of hyperhidrosis has been carried out with techniques that involve either monopolar coagulation or laser injury to the T2 ganglion. Although this has the advantage of being minimally invasive, it has not been established whether these techniques are superior to complete ganglion excision, as carried out during open surgery. A new technique of complete T2 ganglion excision for palmar hyperhidrosis (with T3 ganglionectomy for axillary sweating) was developed using thoracoscopic techniques. Sixteen patients were treated with thoracoscopic T2 ganglion excision on the right side, and simple coagulation (Nd-YAG laser or monopolar) on the left side. Results were excellent with no posttreatment differences between hands at 1 year follow-up. However, long-term follow-up of these patients will be carried out to determine whether differences exist between these two techniques.

Adult↗