Biomedical subjects

M Jones

Publications and source records attributed to M Jones.

At least 559 records · Page 31Linked to original sources

PubMed1992

Resuscitation. Patient and staff attitudes in the context of cancer.

One hundred oncology and hematology cancer patients from a major teaching hospital and their treating doctors were studied regarding their attitudes toward cardiopulmonary resuscitation (CPR). A descriptive approach was used, incorporating semistructured interviews of patients and medical staff and established questionnaire measures, examining knowledge of and attitudes toward disease and treatment, and projected attitude toward CPR and current psychological functioning. One-third of the patient sample anticipated a time when they would not consent to cardiopulmonary resuscitation. This was significantly associated with good disease prognosis. Patients with a psychiatric past history were also overrespresented. It appears that patient attitude to treatment withdrawal and refusal of CPR is related to disease progression and likely to change over time. This supports a dynamic and evolving model of advance directives rather than any fixed decree. Medical staff reported that they planned to provide half the sample with intensive medical treatment (including Intensive Care support in the event of their cardiac arrest), and 32% were designated for ward-based resuscitation only. Eighteen percent would not be resuscitated. These patients were older, had more treatment side effects, and a poorer quality of life. Those patients with either a psychiatric past history or higher ratings of depressive affect were also overincluded in the doctors' "Do-Not-Resuscitate" (DNR) group. These results suggest that there are other qualitative factors (e.g., current psychological functioning and past psychiatric history) that contribute to DNR decisions beyond the usual disease-based criteria seen in formal DNR protocols.

Adult↗

PubMed1992

Relationship between angiographic infarct size and left ventricular filling.

Infarct size may influence left ventricular filling after acute myocardial infarction. Pulsed Doppler transmitral flow velocities were compared in 47 patients at 7 +/- 6 days following acute myocardial infarction and 47 age-matched controls. Patients were stratified by angiographic infarct size into Groups I, II, III (corresponding angiographic hypokinetic scores less than 2; 2-2.99; greater than or equal to 3 SD/cord). Early diastolic transmitral Doppler flow velocities did not differ between infarct groups but atrial transmitral Doppler flow measurements did: peak A velocity (p = 0.001), A velocity time integral (p less than 0.001), and total velocity time integral (p = 0.001). Compared to controls atrial transmitral Doppler flow was augmented in Group I, whilst atrial and total transmitral Doppler flow were depressed in Group III. Peak A velocity and A velocity time integral were inversely related to infarct size (R = -0.44 to -0.54) and directly to left ventricular ejection fraction (R = 0.59 to 0.65). Large infarct size following myocardial infarction is associated with lower atrial and total transmitral Doppler flow velocities.

Adult↗

PubMed1992

Arthroscopic surgery of the knee: its role in the support of U.S. troops during Operation Desert Shield on USNS mercy.

The role of arthroscopy in the preconflict deployment of a large number of military troops is not well defined. Between September 1990 and January 1991, while deployed to the Persian Gulf for Operation Desert Shield 73 patients underwent on-board elective arthroscopy on the USNS Mercy. There were 71 men and two women with an average age of 27 years (range 19-47). Indications for arthroscopy included clinical diagnosis of meniscus tear, acute hemarthrosis, chronic effusion, and intra-articular loose body. Findings at the time of arthroscopy included 34 patients (47%) with meniscus tears; 17 (23%) with anterior cruciate ligament tears; five (7%) with isolated grade II-IV chondromalacia involving the patella, trochlea, femoral condyles, or tibial plateaus; six (8%) with synovitis; four (5%) with osteochondritis dissecans of the medial femoral condyle; two (3%) with a medial retinacular tear secondary to patella dislocation; and 10 (14%) with normal arthroscopic examinations. Forty-nine patients (66%) were returned to duty at an average of 6 days postoperatively, obviating the need to evacuate these patients from the Middle East theatre.

Adult↗

PubMed1992

The pain and discomfort experienced during orthodontic treatment: a randomized controlled clinical trial of two initial aligning arch wires.

A randomized controlled clinical trial was performed to compare the nature, prevalence, intensity, and duration of pain related to the use of a relatively recently developed superelastic arch wire and a more traditional multistranded steel arch wire. Other factors likely to influence the pain experience were also investigated. Forty-three subjects participated in the study, the pain response being assessed by each of the visual analogue scales, the questionnaires, and an analgesic consumption record. In 18 of the 43 subjects a standardized preliminary dental extraction procedure was used as a control. Subsequent to the random allocation of an initial arch wire in 43 patients, 22 of them underwent a second arch wire in the opposing arch, the wire again being determined by random allocation. It was found that the prevalence, intensity, and duration of pain after the insertion of the two types of wire was similar but much greater than in the postextraction control phase. The pain score peaked on the morning after the placement of the arch wire, lasting typically for 5 to 6 days. The pain and discomfort experienced after the insertion of the second arch wire was similar to that of the first, no conditioning response being evident. Overall a diurnal variation was found with a tendency to an increase in pain in the evenings and nights, although this did not greatly affect sleep. The pain response was found to be highly and consistently subjective, not related to the dental arch, crowding, sex, or social class; however, a statistically significant association was found between the age and the pain experienced.

Adolescent↗

PubMed1992

The development of a light curing prosthesis for chest wall replacement.

In conjunction with colleagues in the chemical industry, we have developed and evaluated a new plastic prosthesis which we hope will supplant presently used materials for chest wall replacement. We have modified the basic chemical of a reactive resin routinely used in orthopaedic and dental work by the inclusion of a polypropylene mesh. The resultant material is thin enough to cut with scissors and yet supple enough to shape to fit the defects. It is hardened by exposure to UV light and has a practical cure time when exposed to normal light in the operating theatre. When set it is strong and rigid. The mechanical properties have been studied with the Flexural 3-point bend test and compared with the best of the presently available prostheses. The inert nature of the material was studied in a subcutaneous implant in 29 rats over 3 months. Histology has shown a lack of reactivity. The stability in vivo was studied using the material to replace portions of the chest wall in rabbits for up to 6 months. Subsequent histology and in-vitro testing have proved satisfactory. The ability of this material to withstand the dynamic stresses of the chest wall have been studied by its implantation into the chest wall of 3 minipigs for 6 months. The material looks promising and has proved more "user friendly" than existing prostheses for flat bone replacement. We hope to refine its production to allow its use in humans.

Animals↗

PubMed1992

Evaluation of bcl-2 protein expression and 14;18 translocation as prognostic markers in follicular lymphoma.

Conflicting results have been published on the prognostic significance of t(14;18) in follicular lymphoma: Yunis et al. (1989) reported that its presence indicated poor response to therapy and short survival, whereas Levine et al. (1988) showed no difference in prognosis between cases with and without the translocation. However these results were based on small series of cases and on follow-up periods (no longer than 7 years) which are relatively short for a disease with such a slow clinical evolution. Here we report an investigation of 70 cases of follicular lymphoma with long term follow-up data (up to 17 years). This series has been studied for the presence of the 14;18 translocation and for the expression of bcl-2 protein. Our results show that there are no grounds for considering either the 14;18 translocation or the expression of the bcl-2 protein to be useful prognostic markers in clinical practice.

Blotting, Southern↗

PubMed1992

Molecular and biological properties of an abrin A chain immunotoxin designed for therapy of human small cell lung cancer.

An immunotoxin (IT) comprising abrin A chain attached to the mouse monoclonal antibody SWA11, recognising a cell surface antigen highly associated with human small cell lung cancer (SCLC), was synthesised using a hindered disulphide crosslinker, N-succinimidyl 3-(2-pyridyldithio) butyrate (SPDB), and purified by Blue Sepharose CL-6B affinity chromatography. The IT preparation contained monomeric conjugate, composed of one abrin A chain molecule linked to one SWA11 molecule, and was free from unconjugated A chain or antibody. The IT fully retained the cell-binding capacity of the antibody component and the ribosome-inactivating activity of the A chain. In cytotoxicity assays using the SW2 SCLC cell line in tissue culture, SWA11-SPDB-abrin A chain inhibited the incorporation of 3H-leucine by 50% at a concentration of 10 pM and by 99% at a concentration of 1 nM. The anti-tumour efficacy of the IT was tested in nude mice bearing established s.c. solid SW2 tumour xenografts. A single i.v. injection of SWA11-SPDB-abrin A chain at a non-toxic dose induced a significant 7 to 10 day growth delay that could not be matched by administration of equivalent doses of either unconjugated SWA11 or abrin A chain alone. The results of this study indicate that the antigen recognised by SWA11 is an effective target for therapy of SCLC with A chain ITs in vivo.

Abrin↗

PubMed1992

Effects of oral contraceptives containing oestrogen combined with norethisterone or levonorgestrel on erythrocyte cation transport in normal women.

1. Studies were undertaken in pre-menopausal women to examine the effects of treatment with standard oestrogen-progestogen and progestogen-ony oral contraceptives on erythrocyte Na+,K+ co-transport and Na(+)-Na+ countertransport over 3- and 6-month periods. Concurrent observations were made on other erythrocyte cation transport components, plasma lipid concentrations, plasma renin activity, plasma aldosterone concentration and blood pressure. 2. Na+,K+ co-transport, measured as the ouabain-resistant, frusemide-sensitive component of 86Rb+ influx, and Na(+)-Na+ countertransport, measured as the ouabain-resistant, phloretin-sensitive component of 22Na+ influx, were both increased in women taking, on days 1-21 of their cycle, ethinyloestradiol (30-50 micrograms) combined with norethisterone (1000 micrograms or 500-1000 micrograms) for 3 or 6 months. Neither of these fluxes was increased in a control group of women, or in women treated for the same time periods with ethinyloestradiol combined with levonorgestrel. 3. In a separate study of erythrocyte cation transport (excluding Na(+)-Na+ countertransport), in which women undertook treatment with norethisterone only (350 micrograms/day) for 6 months starting 6 weeks post partum, no changes in Na+,K+ co-transport were observed at 3 or 6 months; there were no changes in cation transport in a corresponding control group. 4. The results of these studies confirm that certain oral contraceptive compounds can alter erythrocyte cation transport, and indicate that norethisterone in higher dose preparations is the component predominantly responsible. The alterations observed could not be explained by a direct link with concurrent changes in plasma triacylglycerol concentrations or in the renin-aldosterone axis and were not closely associated with elevation of blood pressure.

Adolescent↗

PubMed1992

Stresses induced by edgewise appliances in the periodontal ligament--a finite element study.

The quantification of stress in the periodontal ligament is an important concept, as stress in this tissue is transmitted to the alveolus, with subsequent bone remodelling and tooth movement. A number of clinical studies have suggested figures for such an optimal stress range. This study makes use of a finite element technique to determine the stress induced in the periodontal ligament in three dimensions when a maxillary canine tooth is subjected to an orthodontic force similar to that produced by an edgewise appliance. The maximum stress induced at the cervical margin of the periodontal ligament was 0.072 N/mm2, while the maximum stress induced at the level of the apical foramen was 0.0038 N/mm2. These results are discussed in the light of known clinical experience and compared with the stresses produced in the periodontal ligament by other orthodontic forces. The findings would suggest that even with 'perfect' edgewise mechanics it would be difficult to obtain canine movement by pure translation or 'bodily movement.'

Alveolar Process↗

PubMed1992

Candidemia in a tertiary care hospital: epidemiology, risk factors, and predictors of mortality.

Demographic information, risk factors, therapy, and outcome for all patients who had candidemia at Barnes Hospital, St. Louis, between 1 September 1988 and 1 September 1989 were retrospectively reviewed. One hundred six candidemic patients were identified, representing 0.5% of all medical and surgical discharges and 0.33% of total patient discharges. These percentages represent a 20-fold increase in the incidence of candidemia at our hospital in comparison with that during 1976-1979. Candida albicans was the most frequently isolated species (63%), followed by Candida tropicalis (17%), Candida glabrata (13%), Candida parapsilosis (6.5%), and Candida krusei (0.9%). Overall mortality was 57%, and 14 (23%) of 60 deaths occurred within 48 hours of the detection of candidemia. Mortality was associated with higher APACHE II scores (25 for nonsurvivors vs. 16 for survivors; P = .0001), the presence of a rapidly fatal underlying illness (P = .0009), and sustained positivity of blood cultures (P = .02). In cases of sustained candidemia, the isolation of non-albicans Candida species also correlated with increased mortality (8 of 8 vs. 10 of 21; P = .005). Thirty candidemic patients (28%) did not receive any antifungal therapy, and 19 (63%) of these untreated patients died. Eleven untreated patients (37%) survived without sequelae. There has been a marked increase in the incidence of candidemia in our institution that is associated with a high overall mortality. Candidemia lasting less than 24 hours was associated with a lower mortality than was that of longer duration. Severity of illness and duration of candidemia should be used as stratifying factors in prospective studies to determine optimum therapy.

Adolescent↗

PubMed1992

Development and follicular localization of tolerant B lymphocytes in lysozyme/anti-lysozyme IgM/IgD transgenic mice.

To analyse mechanisms of immunological self-tolerance, a detailed comparison of the development and fate of lysozyme-specific B lymphocytes was carried out in transgenic mice expressing rearranged anti-lysozyme IgM/IgD Ig transgenes in the absence or presence of an additional transgene encoding lysozyme itself. In the absence of lysozyme, B cell development, localization, and differential expression of transgene-encoded IgM and IgD occurred in the normal sequence in Ig transgenic mice, establishing that these animals provide a physiological model for studies of B cell selection in vivo. By contrast, in lysozyme-expressing double-transgenic mice, tolerant lysozyme-reactive B cells persisted within the follicular mantle zones in the spleen, lymph nodes, and Peyer's patches, but were eliminated from the splenic marginal zones. It could be shown that lysozyme-binding and induction of tolerance occurred as soon as surface Ig was expressed on immature B cells in the bone marrow of the double-transgenic mice although this did not prevent maturation, emigration from the bone marrow, and localization in peripheral lymphoid follicles. These findings, together with recent examples of aborted maturation of self-reactive B cells, indicate two functionally distinct antigen receptor signalling events in immature B cells and suggest a unique role for the follicular microenvironment.

Animals↗

PubMed1992

The effectiveness of preemployment drug screening in the prediction of employment outcome.

Studies of adverse employment outcomes associated with positive preemployment drug screens have tracked employees for only about 1 year. Changes in drug use after hire may invalidate the predictions of employment outcome in later years which are essential for cost-benefit analyses. This blinded, prospective cohort study tracks absence, industrial accidents, occupational injuries, discipline, and turnover in 2537 screened employees through an average of 2 years. Marijuana-positive urines predicted increased turnover, accidents, injuries, discipline, and absence, but these risks appeared lower in the second year than the first. Cocaine-positive urines predicted increased turnover, accidents, injuries, discipline, and absence at levels not consistently different than the first year. Cost-benefit analyses of drug screening project employment risks throughout employees' careers. This study raises the possibility that elevated risks may decrease after the first year.

Boston↗

PubMed1992

Population-based survey of human sodium and potassium excretion.

1. During the 1989 National Heart Foundation Risk Factor Prevalence Survey a subsample in Hobart collected 24 h urine samples to measure electrolyte excretion. 2. The ranges were 30-344 mmol/24 h for Na+ excretion (mean 160 mmol/24 h for men, 124 mmol/24 h for women), and 25-119 mmol/24 h for K+ excretion (mean 77 mmol/24 h for men, 68 mmol/24 h for women). 3. As in other surveys, women excreted about 20-25% less Na+ and K+ than men, although there was no significant sex difference in the ratio of Na+/K+ excretion. 4. The recommended dietary intake (RDI) for Na+ and K+ was followed simultaneously by 19% of subjects, and 13% had a 24 h urinary Na+/K+ ratio less than or equal to 1.0. 5. Observance of the RDI limited the value of iodized salt for goitre prophylaxis. 6. Sodium excretion rates were outside the therapeutic range of thiazide diuretics in 22% of subjects. 7. Diet groups for long-term prospective cohort studies to test the prophylactic value of avoiding salt could apparently be recruited from existing subsamples of the population.

Adult↗

PubMed1992

Current management of duplex-system ureteroceles: experience with 41 patients.

Experience is described of 41 infants and children with duplex-system ureteroceles, 25 presenting clinically and 16 by prenatal ultrasonography. Bladder outflow obstruction was rare but lower polar vesicoureteric reflux (VUR), usually of lesser grades, was common. Upper polar function, as assessed by 99mTc-DMSA, was negligible in children with truly ectopic ureteroceles but well preserved in those where the lesion lay wholly intravesically. Lower polar function was good, even in the presence of secondary obstruction, except in 2 infants with major VUR. Twenty-three patients were treated by upper polar nephrectomy plus aspiration of the ureterocele; 2 subsequently required ureterocele excision. Histology of excised specimens indicated that a more conservative approach would not have been rewarded. Where upper polar function was good, conservation was maintained in 3 cases by pyelopyelostomy and in 5 more by excision of the ureterocele plus bipolar ureteric reimplantation. Other operative strategies were employed in 2 cases. Finally, a defined group of 8 children was managed expectantly without untoward results. It was concluded that the variable anatomy and function associated with duplex-system ureteroceles require a flexibile approach to treatment, including, possibly, no treatment at all.

Child↗

PubMed1992

Dexamethasone increases plasma amino acid concentrations in bronchopulmonary dysplasia.

Nine ventilated low birthweight babies were treated with dexamethasone (0.6 mg/kg/day). Appreciable suppression of weight gain was accompanied by uraemia and significant increases in the concentration of all amino acids except phenylalanine, tyrosine, threonine, and glutamate. Ornithine, citrulline, alanine, glutamine, and cystine concentrations increased threefold or more. The findings could not be explained by changes in dietary intake and presumably reflect pronounced catabolism, though the effects of dexamethasone on intermediary metabolism and membrane transport could also play a part.

Amino Acids↗

PubMed1992

Incidence of normal micturition in myelomeningocele patients.

Among 108 consecutive patients with myelomeningocele aged 5-12 years initially treated by a selective policy, seven (6.5%) achieved spontaneous urinary continence, five with normal micturition and two with urgency. All had positive conus reflexes and incomplete cord lesions which, with one exception, comprised motor as well as sensory sacral sparing.

Child↗

PubMed1992

Monoclonal antibody JC1: new reagent for studying cell proliferation.

AIM: To characterise a newly developed mouse monoclonal antibody JC1 which recognises a nuclear antigen present in proliferating cells in normal tissues and neoplastic lesions, and which is absent in resting cells. METHODS: The methodology was established using a representative range of frozen sections from normal tissues and from certain tumours which were immunostained with antibodies Ki67 and JC1. The molecular weight of the antigen recognised by JC1 was obtained by western blot analysis and this was compared with that of Ki67. IM-9 cell lysates containing Ki67 derived plasmids were also tested with JC1 antibody. RESULTS: Biochemical investigation indicated that the antigen recognised by JC1 gives two molecular weight bands of 212 and 123 kilodaltons, which is distinct from the well characterised anti-proliferation monoclonal antibody Ki67 (395-345 kilodaltons). In addition recombinant Ki67 protein is not recognised by JC1. Immunohistological reactivity was seen in areas known to contain numerous proliferating cells such as lymphoid germinal centres, splenic white matter, cortical thymocytes and undifferentiated spermatogonia. In tumours many cells from adenocarcinomas, oat cell carcinomas, squamous cell carcinomas of lung, and seminomas were labelled by JC1 with a distribution and proportion similar to that seen with Ki67. In normal tissues the only apparent difference was in testis where JC1 stained a considerably greater number of cells than Ki67. In all cases studied the new antibody showed nuclear reactivity only. JC1 did not show any cytoplasmic crossreactivity with squamous cells as is frequently seen with Ki67. CONCLUSION: Antibody JC1, which recognises a nuclear antigen present in proliferating cells, should provide a useful adjunct to Ki67 as a marker of proliferation especially in those cases such as squamous cell carcinomas where a Ki67 index cannot be determined.

Animals↗

PubMed1992

Heterogeneity of vascular endothelial cells with relevance to diagnosis of vascular tumours.

AIMS: To determine the distribution of factor VIII related antigen, CD31, CD34 and CD36 in normal and malignant human vascular tissues using a panel of well characterised monoclonal antibodies. METHODS: Frozen and fixed material from a wide range of normal tissues and routinely processed material from 43 benign and malignant vascular tumours were examined. Single immunocytochemical labelling was performed using the APAAP technique. Double staining involved the sequential use of APAAP with the peroxidase method. RESULTS: Human vascular endothelium was antigenically heterogeneous. One of the most restricted markers was factor VIII related antigen, despite its having been widely used in diagnostic pathology as a marker of vascular endothelium and of the tumours which arise from it. Three antibodies against factor VIII related antigen, CD31 (JC70) and CD34 (QBend 10) were identified as immunostaining routinely processed, formalin fixed, paraffin wax sections. Each antibody gave different staining when tested on a range of vascular tumours, both benign and malignant. CONCLUSIONS: A small panel of three reagents (factor VIII related antigen, CD31 (JC70) and CD34 (QBend 10)) should be used by diagnostic pathologists who want to show the presence of cells of endothelial origin in routine material.

Antigens, CD↗