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Biomedical subjects

M Thomas

Publications and source records attributed to M Thomas.

At least 613 records · Page 34Linked to original sources
PubMed1992

In vitro sensitized autologous tumorocidal lymphocytes to colonic adenocarcinoma.

We report a method of developing a population of tumorocidal lymphocytes by culturing peripheral blood mononuclear cells (PBMC) with live isogenic colorectal tumour cells in a mixed cell culture. When the proportion of PBMC to tumour cells is 100:1, eradication of the tumour cell population results. The proportion of activated lymphocytes in culture increases with cytotoxic activity as demonstrated by the presence of the cytotoxic enzyme serine esterase in the lymphocyte granules.

Adenocarcinoma↗
PubMed1992

Evaluation of purified protein derivative in the laboratory diagnosis of tuberculous meningitis.

An enzyme-linked immunosorbent assay (ELISA) was standardised for the quantitation of IgG antibody in cerebrospinal fluid (CSF) specimens of patients with tuberculous meningitis (TBM). Purified protein derivative (PPD1) from H37Ra M tuberculosis was used as the antigen in the assay. The sensitivity of the ELISA with this antigen was evaluated in the CSF of 10 culture positive and 40 culture negative patients with TBM. The specificity of the assay was evaluated in the CSF of 50 patients with non-tuberculous neurological diseases (control group). The results obtained with this antigen were compared with commercially available tuberculin purified protein derivative (PPD2) and BCG antigens. PPD2 gave false negative results (50%) in culture positive patients with TBM, and BCG antigen gave false positive results in 32% of non-tuberculous subjects. PPD1 gave a sensitivity of 60% in culture negative patients with TBM and no false positive reactions in the non-tuberculous group. PPD1 antigen, in contrast to other mycobacterial antigens, can be very easily prepared in any routine laboratory, and this antigen is recommended for use as an aid in the laboratory diagnosis of TBM, particularly in culture negative patients with TBM.

Antibodies, Bacterial↗
PubMed1992

The incredible odontogenic keratocyst.

The aggressive behavior and high recurrence rate of the odontogenic keratocyst make it unique among odontogenic cysts. Successful treatment requires meticulous evaluation and diagnosis, proper surgical management and continued follow up.

Epithelium↗
PubMed1991

Structure-function relationships in the cysteine proteinases actinidin, papain and papaya proteinase omega. Three-dimensional structure of papaya proteinase omega deduced by knowledge-based modelling and active-centre characteristics determined by two-hydronic-state reactivity probe kinetics and kinetics of catalysis.

1. A model of the three-dimensional structure of papaya proteinase omega, the most basic cysteine proteinase component of the latex of papaya (Carica papaya), was built from its amino acid sequence and the two currently known high-resolution crystal structures of the homologous enzymes papain (EC 3.4.22.2) and actinidin (EC 3.4.22.14). The method used a knowledge-based approach incorporated in the COMPOSER suite of programs and refinement by using the interactive graphics program FRODO on an Evans and Sutherland PS 390 and by energy minimization using the GROMOS program library. 2. Functional similarities and differences between the three cysteine proteinases revealed by analysis of pH-dependent kinetics of the acylation process of the catalytic act and of the reactions of the enzyme catalytic sites with substrate-derived 2-pyridyl disulphides as two-hydronic-state reactivity probes are reported and discussed in terms of the knowledge-based model. 3. To facilitate analysis of complex pH-dependent kinetic data, a multitasking application program (SKETCHER) for parameter estimation by interactive manipulation of calculated curves and a simple method of writing down pH-dependent kinetic equations for reactions involving any number of reactive hydronic states by using information matrices were developed. 4. Papaya proteinase omega differs from the other two enzymes in the ionization characteristics of the common (Cys)-SH/(His)-Im+H catalytic-site system and of the other acid/base groups that modulate thiol reactivity towards substrate-derived inhibitors and the acylation process of the catalytic act. The most marked difference in the Cys/His system is that the pKa for the loss of the ion-pair state to form -S-/-Im is 8.1-8.3 for papaya proteinase omega, whereas it is 9.5 for both actinidin and papain. Papaya proteinase omega is similar to actinidin in that it lacks the second catalytically influential group with pKa approx. 4 present in papain and possesses a catalytically influential group with pKa 5.5-6.0. 5. Papaya proteinase omega occupies an intermediate position between actinidin and papain in the sensitivity with which hydrophobic interaction in the S2 subsite is transmitted to produce changes in transition-state geometry in the catalytic site, a fact that may be linked with differences in specificity in P2-S2 interaction exhibited by the three enzymes.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1991

Blood lipid levels in New Zealand.

OBJECTIVES: the study aimed to determine age and gender specific levels of lipids and lipoproteins in New Zealanders. Participants were randomly selected from 20 general electoral roles, and from a sample of 15-18 year olds. METHODS: plasma cholesterol, LDL cholesterol, HDL cholesterol and triglyceride levels were measured in 2941 men and women aged 15-99 years. RESULTS: mean (SD) plasma cholesterol was 6.0 (1.3) mmol/L in men and 6.1 (1.3) mmol/L in women. There was a marked variation in total cholesterol and calculated LDL cholesterol with age, and the pattern was different in men and women. There was also a considerable regional variation; levels tending to increase from north to south. Overall mean cholesterol levels adjusted for age and geographical distribution were 5.8 and 6.0 mmol/L for men and women respectively. CONCLUSION: the fact that approximately a third of the adult population in New Zealand under 65 years have cholesterol levels greater than 6.5 mmol/L indicates the need for effective diet and lifestyle changes to reduce the high rates of CHD.

Adolescent↗
PubMed1991

Can urinary thyroid hormone loss cause hypothyroidism?

Four patients presented with nephrotic syndrome associated with hypothyroidism; none had thyroid antibodies. Hypothyroidism resolved on remission of nephrotic syndrome in two patients; thyroxine (T4) replacement was ineffective during periods of gross proteinuria in another, and the fourth had had normal thyroid function a year before presentation. Urinary T4 excretion was measured in ten further patients with proteinuria. It was detectable in the urine in five, who had significantly lower serum free T4 (8.5 [95% confidence interval 5.8-11.2] vs 13.9 [11.1-16.7] pmol/l; p less than 0.01) and free triiodothyronine (3.1 [2.2-4.0] vs 4.9 [3.8-6.0] pmol/l; p less than 0.01) concentrations than the five patients without detectable urinary T4.

Aged↗
PubMed1991

Tuberculosis in New South Wales.

Surveillance of tuberculosis in New South Wales depends on notification of cases by medical practitioners and careful follow-up by public health nurses dedicated to the control of tuberculosis. Evaluation of tuberculosis surveillance data enables identification of patterns of infection, highlighting areas requiring specific interventions. In 1986, 290 cases of tuberculosis were notified to the Department of Health, New South Wales. The majority of patients (72.8%) were diagnosed as having pulmonary disease. The highest rates of infection were in people from Southeast Asian countries. Whereas 5.2% of cases were identified when the patients entered Australia, a substantial proportion of diagnoses (23.1%) were made in people who had been resident in Australia for 10 or more years. This article highlights the need to continue efforts to improve tuberculosis surveillance and control programmes in New South Wales.

Adolescent↗
PubMed1991

Granulocyte colony-stimulating factor (G-CSF) treatment in a neutropenic leukemia patient with diffuse interstitial pulmonary infiltrates.

Adult respiratory distress syndrome (ARDS) in patients suffering from acute leukemia usually occurs during chemotherapy-induced neutropenia. In addition, intensified chemotherapy with high-dose cytosine arabinoside and mediastinal irradiation may contribute to the development of ARDS. This complication is usually refractory to conservative treatment with antibiotics, steroids, and mechanical ventilation. In this report, we describe a 25-year-old patient with acute lymphoblastic leukemia who developed ARDS during the phase of chemotherapy-induced neutropenia. Subcutaneous administration of granulocyte colony-stimulating factor (G-CSF) at doses of 300-600 micrograms/day led to a prompt increase of peripheral granulocyte counts. With resolution of neutropenia, respiratory function gradually improved, and mechanical ventilatory support was stopped after 2 weeks. From this observation we surmise that the application of G-CSF may be an effective therapeutic approach for preventing the fatal outcome of ARDS in leukemia patients with bone marrow aplasia.

Adult↗
PubMed1991

Rapid diagnosis of tuberculous meningitis with a dot enzyme immunoassay to detect antibody in cerebrospinal fluid.

A simple dot enzyme immunoassay (Dot-EIA) was carried out to detect antibody to Mycobacterium tuberculosis antigen 5 in cerebrospinal fluid (CSF) specimens from 40 patients with a clinical diagnosis of tuberculous meningitis (TBM). The assay gave a positive reaction in all ten patients with culture proven TBM. In 30 culture negative patients with TBM, the assay was positive at a titre of 1:16 in 18 patients. In 40 patients with non-tuberculous neurological diseases (control group) the assay was negative at a titre of 1:16. The Dot-EIA had an overall sensitivity of 70% and a specificity of 100% in the diagnosis of TBM. This assay could be used as a rapid screening test to establish the diagnosis of TBM, particularly in patients in whom bacteriological investigations for Mycobacterium tuberculosis in CSF specimens are negative.

Adolescent↗
PubMed1991

Rickets in Nigerian children: a consequence of calcium malnutrition.

Eleven Nigerian children with clinically and radiologically proven rickets were assessed biochemically. The children had low or low normal concentrations of total and corrected calcium, and elevated plasma alkaline phosphatase (ALP) activity, but normal plasma phosphate concentrations. Their serum 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) concentrations were not significantly different from those in controls, but the ratio of 1,25-(OH)2D to 25-OHD was significantly greater than that in controls. Parathyroid hormone (PTH) concentrations were greater in rachitic children, and there was a significant correlation between 1,25-(OH)2D and PTH concentrations. Osteocalcin concentrations in rachitic children were not significantly different from those in controls, but they were markedly elevated in the three patients with the highest 1,25-(OH)2D and PTH concentrations. One child, from whom a sample of bone (from a corrective osteotomy) was available for histological examination, showed markedly thickened osteoid seams, characteristic of rickets. All the rachitic children had a calcium intake of less than 150 mg daily. Treatment of these rachitic children with calcium gluconate (1 g/d) led to clinical, radiological, and biochemical healing of rickets. We conclude that rickets in Nigerian children is not due to vitamin D deficiency, but to a lack of calcium. This observation has implications regarding the pathogenesis, treatment, and prevention of rickets/osteomalacia in Nigeria and possibly other African and tropical countries.

Alkaline Phosphatase↗
PubMed1991

Development of an in vitro temporomandibular joint cartilage analog.

A method of producing an in vitro cartilage tissue analog by traditional organ culture methods in an animal model is presented. The resultant tissue analog had the clinical appearance and characteristics of the temporomandibular joint disc. Development of such an analog for in vivo autografting could provide an alternative to present methods for disc repair.

Animals↗
PubMed1991

1H-NMR and HPLC studies of the changes involved in volume regulation in the muscle fibres of the crab, Hemigrapsus edwardsi.

1. The process of cell volume readjustment, during adaptation to salinity changes, in muscle fibres of the euryhaline New Zealand shore crab, Hemigrapsus edwardsi, involve large changes in the amounts of free amino acid. 2. These are taurine, proline, alanine, arginine, glutamic acid, glycine and serine. 3. These changes may be quantified by High Performance Liquid Chromatography, and qualitatively demonstrated by proton nuclear magnetic resonance spectroscopy.

Adaptation, Physiological↗
PubMed1991

Increased postoperative pain and consumption of analgesics following acupuncture.

Acupuncture was given to patients before (preoperative-acupuncture group, PRE-ACU, n = 25) or after (postoperative-acupuncture group, POST-ACU, n = 25) operative removal of impacted mandibular third molars. Sixty patients did not receive acupuncture and participated as a control group (CG). All patients completed a questionnaire in order to characterize state tension and stress, degrees of neuroticism, extroversion, depression and psychosomatic disorders. We also recorded intraoperative discomfort and pain intensity, postoperative pain intensity and consumption of analgesics for 72 h. The PRE-ACU was significantly more tense following surgery and found the operative procedure more unpleasant than the other two groups. The PRE-ACU further rated intraoperative pain intensity higher than the CG and experienced higher pain intensity immediately postoperatively compared with POST-ACU and CG. Of the PRE-ACU patients 15/24 needed additional local anesthesia intraoperatively while none in the POST-ACU or CG requested extra lidocaine. Postoperatively patients in both PRE- and POST-ACU reported a higher total sum of pain scores (pain intensity) and the PRE-ACU consumed more analgesics compared with the CG. A significantly larger number of patients suffering from "dry socket" (a complication during wound healing) was found in both PRE- and POST-ACU compared with the CG. No correlation was found between assessed personality characteristics and reported postoperative pain/consumption of analgesics in any group and could thus not explain the observed differences between the groups. The reason for our unexpected "negative" findings is unclear but some hypothetical explanations are discussed.

Acupuncture Therapy↗
PubMed1991

The relationship of staff:client ratios, interactions, and residential placement.

The behavior of staff and persons with severe handicaps was surveyed in nine settings, including four traditional institutions, three large community-based units, and two groups of small homes. Data were collected that established the relationship among staff:client interactions, client responding, and the size of staff:client groups. The latter showed that the institutions were characterized by larger client and staff groups than the large community units. Large client and staff groups were virtually absent in the small homes. Two general conclusions could be drawn about the relationship between staff:client ratios and client behavior: (a) when one or two staff were together, improvements in the level of the staff interactions and client adaptive functioning occurred as the client group decreased in size and the staff size remained constant; (b) improvement in staff performance and client behavior arising from the addition of staff to a client group of a given size was marginal or nonexistent. The results were discussed in terms of their implications for the design of residential environments.

Activities of Daily Living↗
PubMed1991

New technique for selective transcervical osteal salpingography and catheterization in the diagnosis and treatment of proximal tubal obstruction.

Transcervical fallopian tube catheterization to recanalize the proximal (uterine end) fallopian tube are rapidly gaining acceptance for the diagnosis and treatment of tubal obstruction. We describe a new simplified technique for performing this procedure. Our technique obviates the need for hysterocaths and assures delivery of an atraumatic spherical tip of a cannula to the uterotubal junction. Compared with other techniques, it is quick with no need for IV or paracervical anesthesia or analgesia, no cervical dilatation, nor the use of Hyskon nor CO2 insufflation devices.

Adult↗