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Biomedical subjects

G M Jones

Publications and source records attributed to G M Jones.

At least 55 records · Page 3Linked to original sources
PubMed1993

Characterization of MHC class I restricted cytotoxic T cell responses to tax in HTLV-1 infected patients with neurologic disease.

To understand the nature of the cytotoxic T cell response generated in human T lymphotropic virus type 1 (HTLV-1)-infected patients with HTLV-1-associated myelopathy/tropical spastic paraparesis, we cloned CTL from the peripheral blood and cerebrospinal fluid from patients with neurologic diseases and demonstrated the presence of HLA-A2, A3, and B14 restricted responses to the HTLV-1 p40x (tax) protein. We identified the minimal amino acid residues within the epitopes required for binding and recognition by HLA-A2- and B14-restricted CTL, identified the critical residues within the peptide sequence defining the HLA-A2-restricted response, and demonstrated that CTL can lyse T cells infected with HTLV-1. This study shows that the CTL response to HTLV-1 tax in patients with neurologic diseases is heterogenous in nature and is not confined to patients of a single HLA haplotype or to a specific region of the tax protein.

Amino Acid Sequence↗
PubMed1992

Detection of antigen specific T lymphocytes by determination of intracellular calcium concentration using flow cytometry.

We present a method for the detection of lymphocytes with specific reactivity to antigens on stimulator cells using flow cytometry. Cultured human T lymphocytes were loaded with the intracellular fluorochrome indo-1 and were mixed with stimulator cells. Using flow cytometry we could detect a specific increase in intracellular calcium in the T lymphocytes as well as conjugation between the T cells and the stimulator cells. Examination of antigen-specific CD4+ and CD8+ T cell clones demonstrated that the vast majority of T cells which were conjugated to antigen-bearing stimulator cells manifested a rapid increase in intracellular calcium. In contrast T cells conjugated to stimulator cells which did not bear specific antigen demonstrated no such increase in calcium. A similar finding was observed when examining polyclonal tumor infiltrating lymphocytes obtained from patients with melanoma. Tumor infiltrating lymphocytes with specific antitumor reactivity demonstrated an increase in intracellular calcium when conjugated to autologous tumor but not to allogeneic melanoma. In contrast to the T cell clones, only a small subpopulation of tumor infiltrating lymphocytes manifested this specific signal upon conjugation with autologous tumor. This suggests that tumor infiltrating lymphocyte cultures contain T cells with varying reactivities to tumor or may also imply heterogeneity in the stimulating tumor cell lines. The method allows for the detection of specific T cells on an individual cell basis in real time. The procedure is not lethal to the cell and sorting and subculturing of reactive T cell populations can be readily performed. The method could also be used to sort stimulator cells based on their ability to elicit an increase in intracellular calcium in selected T cells.

CD4 Antigens↗
PubMed1992

Effects of acute subcutaneous nicotine on attention, information processing and short-term memory in Alzheimer's disease.

This single-blind, placebo controlled study reports on the effects of administering three acute doses of nicotine (0.4, 0.6 and 0.8 mg) subcutaneously to a group of Alzheimer's disease (DAT) patients (n = 22), young adult controls (n = 24), and normal aged controls (n = 24). The study extends our previous findings obtained using smaller groups of subjects. Drug effects were examined on three computerised tests: the first measuring rapid visual information processing, sustained visual attention and reaction time (RVIP task); a delayed response matching to location-order task measuring sustained visual attention and visual short-term memory (DRMLO task); and a finger tapping test measuring simple reaction time (FT task). The critical flicker fusion test (CFF) was used as a measure of perception and the WAIS digit span forwards (DS), of auditory short-term memory. Tests were graded in difficulty, titrated to avoid floor and ceiling effects so that meaningful, direct comparisons between groups could be made. Nicotine significantly improved sustained visual attention (in both RVIP and DRMLO tasks), reaction time (in both FT and RVIP tasks), and perception (CFF task--both ascending and descending thresholds). Nicotine administration did not improve auditory and visual short-term memory. There were no consistent, overall patterns of difference in performance between smokers and non-smokers in the control groups, or between males and females in any group. Despite the absence of change in memory functioning, these results demonstrate that DAT patients have significant perceptual and visual attentional deficits which are improved by nicotine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

In-line skating: physiological responses and comparison with roller skiing.

The use of in-line skates has become popular in recent years for recreational and conditioning purposes. This investigation evaluated the physiological responses of ten subjects during in-line skating on a flat track with three different in-line skating techniques. The double pole technique demonstrated the greatest economy with oxygen uptake requirements that were approximately 12% lower (p less than 0.05) than conventional skating (without poles) or the V1 skate technique. Across the investigated velocity spectrum of 14.6 to 18.0 km.h-1, individuals with an average fitness level of 40 ml.kg-1.min-1 will achieve exercise intensities of 68-90% of maximum oxygen uptake using the conventional skating and V1 skate techniques on flat terrain. These exercise intensities are appropriate for cardiorespiratory training. However, high fit individuals who are attempting to elicit a cardiorespiratory training effect using in-line skates with rolling resistances similar to those tested may need to perform uphill interval work or skate at higher velocities which may be technically difficult and may be unsafe in some training environments. Comparison of the present data with previously published data on roller skiing demonstrates that differences in physiological responses for the two modes of exercise are the result of differences in rolling resistances between the devices. Measurements of rolling resistance and comparison of the oxygen uptake requirements for double polling on both devices allow for the mechanical efficiency to be estimated at approximately 18% for this mode of locomotion.

Analysis of Variance↗
PubMed1992

Use of an enzyme-linked immunosorbent assay to monitor the control of Staphylococcus aureus mastitis.

Conventional culture methods were used to evaluate the ability of an ELISA to identify Staphylococcus aureus IMI. The test was 96% accurate; sensitivity was 90%, and specificity was 97%. The test was used to screen preserved milk samples rapidly in 10 cooperator herds. Prevalence of IMI was greater than 10% in 6 herds at the first test. Average prevalence of cows scoring +2 (suspect) and +3 (positive) was 12.6%. Prevalence declined during the 12-mo study. Incidence of new IMI decreased from 7.9% at 6 mo to 3.6% at 12 mo. Rinsing teat cup liners with a 25-ppm iodophor or 100-ppm chlorine solution reduced the presence of S. aureus on the milking machine liners by 97%. Elevated scores were correlated with increases in lactation number. Milk antibody concentrations changed quadratically with increasing SCC. The SCC increased as milk antibody concentration increased. In 38 dairy herds, bulk tank antibody tests reflected herd prevalence of S. aureus infection. The average prevalence was 15.0% in 87 herds in which all lactating cows were tested.

Animals↗
PubMed1991

A simple method for fixation of mandibular fractures.

A useful but underused technique of mandibular fixation is described. Its main advantages over more traditional techniques are that it is easily and rapidly applied, suitable for both children and adults, and generally well tolerated. The method can be employed where only a few teeth are present and in displaced fractures together with an intraosseous buccal plate wire. It is a method that can be recommended for use in nonmaxillofacial units and in areas where only basic equipment and facilities are available.

Bone Wires↗
PubMed1991

Trends in the aetiology of maxillofacial fractures in the United Kingdom (1977-1987).

A survey was undertaken to assess changes in the aetiology of maxillofacial fractures in the United Kingdom between 1977 and 1987, using data which had been collected in British departments of Oral and Maxillofacial Surgery. Data were available from units serving 17 million people and included details of patients from a broad spread of rural and urban areas. Analysis of data from the 27 maxillofacial units able to supply details from both 1977 and 1987 showed an overall increase of 20% in numbers of patients with maxillofacial fractures, though a trend towards fewer severe injuries was also a feature over the same period. Numbers of patients injured in road accidents had decreased by 34%, numbers of patients injured in assaults had increased by 47% whilst numbers of patients injured in all other ways had increased by 39%.

Accidental Falls↗
PubMed1991

Effects of technique and pole grip on physiological demands of roller skiing on level terrain.

This study evaluated the physiological responses to roller skiing with three different techniques, and compared the physiological responses during roller skiing with a standard pole grip and an innovative "anatomical" pole grip. Data were collected on ten experienced cross-country ski racers while roller skiing with the double pole, V1 skate, and kick double pole techniques on a flat track at mean (+/- SD) velocities of 14.6 +/- 0.2, 16.4 +/- 0.3, and 18.0 +/- 0.4 km.h-1. The kick double pole technique induced the highest (p less than 0.05) oxygen uptakes, heart rates, and ventilations. The double pole technique elicited the lowest (p less than 0.05) oxygen uptakes, and the V1 skate technique elicited the lowest (p less than 0.05) perceived effort and respiratory exchange ratios. Comparison of the two pole grips showed no differences in the physiological responses and perceived effort. While the V1 skate technique is not the most economical roller skiing technique on flat ground, the lower associated perceived effort and respiratory exchange ratios may at least partially account for the general preference of cross-country ski racers to use the V1 skating technique rather than the double pole technique on flat terrain.

Adult↗
PubMed1990

Parotid gland malignancy presenting as temporomandibular joint pain or dysfunction.

Temporomandibular joint pain and dysfunction is a common complaint and a frequent cause of referral to oral and maxillofacial surgeons. The importance of considering malignant disease in the differential diagnosis is illustrated by the following cases of parotid gland neoplasia which were referred as temporomandibular joint dysfunction.

Aged↗
PubMed1990

Mapping the fine specificity of a cytolytic T cell response to HIV-1 nef protein.

Epitope mapping of a MHC class I-restricted cytotoxic T cell response to nef, a regulatory protein of HIV, was performed with fresh PBMC from HIV-seropositive donors and target cells pulsed with a panel of overlapping peptides of the nef protein. These nef-specific CTL recognized a synthetic peptide of 10 residues derived from a nonamphipathic, highly conserved region of the nef protein in association with the HLA A3.1 molecule. Using human cell transfectants expressing mutations of the A3 molecule, we demonstrated that the amino acid at position 152 of the A3.1 molecule appears to be critical for detection of this response. Thus, rapid analysis of the epitopes of HIV proteins stimulating CTL responses can be achieved using a combination of fresh donor PBMC and target cells pulsed with synthesized peptides.

Amino Acid Sequence↗
PubMed1990

Enhanced chromatid damage in blood lymphocytes after G2 phase x irradiation, a marker of the ataxia-telangiectasia gene.

An assay for ataxia-telangiectasia (A-T) heterozygotes, i.e., healthy carriers of the A-T gene(s), requiring only a small sample (3.5 mL) of peripheral blood, is described. Frequencies of chromatid aberrations in phytohemagglutinin-stimulated blood lymphocytes collected by demecolcine from 0.5 hour to 1.5 hours after x irradiation with 58 roentgens were twofold to threefold higher in A-T heterozygotes than in clinically normal controls and twofold to three-fold higher in A-T patients (homozygotes) than in A-T gene carriers. The persistence of chromatid breaks and gaps in lymphocytes following radiation-induced DNA damage during G2 suggests a deficiency or deficiencies in DNA repair that may be the defect at the molecular level that results in the enhanced radiosensitivity and cancer proneness characterizing A-T gene carriers and patients.

Adolescent↗
PubMed1990

Metastatic renal clear cell carcinoma of the jaws. Two cases illustrating clinical and pathological diagnostic problems.

Two cases of metastatic renal clear cell carcinomas of the mandible are presented in which the jaw symptoms preceded the discovery of the primary lesions. Their presentation mimicked vascular abnormalities both clinically and on special investigations and both required biopsy, one of which was a major excision, for diagnosis. The histological differential diagnosis of metastatic renal clear cell carcinoma from other clear cell tumours arising in the orofacial tissues can also be difficult, often requiring specialised knowledge and techniques. These points illustrate that the differential diagnosis of a pulsatile soft tissue jaw tumour developing below intact mucosa and eroding bone, should include metastatic tumour as well as vascular anomaly, vasoformative tumour, extra nodal lymphoma and primary bone tumour.

Adenocarcinoma↗
PubMed1990

Primary bone cyst of the mandibular condyle.

Cysts of the mandibular condyle are rare and their diagnosis and treatment can be difficult. A case in a young girl is described where the histology was that of a solitary bone cyst but the presentation and behaviour more closely resembled an aneurysmal bone cyst.

Bone Cysts↗
PubMed1990

Fracture of the articular eminence. Report of a case.

A case of compound fracture of the articular eminence is presented. The injury was sustained as a result of direct trauma which also caused a mandibular symphyseal fracture. Management comprised repositioning and support of the fractured fragment by means of sutures and the application of intermaxillary fixation. There was no long-term limitation of mandibular movement nor was there neurological or hearing deficit as a result of either injury or treatment.

Accidents, Traffic↗
PubMed1990

The effect of exhaled alcohol on the performance of the Datex Capnomac.

We investigated the response of the Datex Capnomac to alcohol in expired air. The greatest response was seen when the Capnomac was set to monitor halothane. There was an approximately linear correlation with blood alcohol levels. This effect is of sufficient magnitude to introduce inaccuracies in the measured concentration of halothane.

Carbon Dioxide↗