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Biomedical subjects

L Welsh

Publications and source records attributed to L Welsh.

14 recordsLinked to original sources
PubMed2004

Drug treatment of essential hypertension: the case for initial combination therapy.

Essential hypertension is a major cause of cardiovascular morbidity and mortality in the Western world, yet it remains poorly controlled. Single drug-antihypertensive therapy is unsuccessful in up to half of all patients with hypertension; although lack of adherence may account for a proportion of this, there is evidence of considerable variation in the response of different hypertensive patients to different drug classes. A number of algorithms have been proposed in the literature, with a view to predicting an individual's response to different antihypertensive agents. However, even using such algorithms, hypertension control remains problematic, and they are frequently difficult to apply in everyday clinical practice. Initiation of treatment with low-dose combination antihypertensive therapy, using a drug which reduces total body sodium and/or volume in combination with a drug which blocks the renin-angiotensin system, provides an effective and easily applicable means to improve hypertension control in the primary care setting.

Adrenergic beta-Antagonists↗
PubMed1997

The acute effects of exercise on bone turnover.

Exercise is known to have long-term benefits on bone mass, but little is known about the short-term effects of exercise on bone turnover. The purpose of this study was to investigate whether acute effects of exercise on bone remodelling could be detected by measuring blood and urinary markers of bone turnover. We measured biochemical markers of bone turnover in ten healthy, young men before and up to 32 hours after 30 minutes of brisk treadmill walking. Blood samples were taken before, immediately after and at 0.5, 1, 8, 24 and 32 hours after the exercise. These were assayed for osteocalcin and bone specific alkaline phosphatase. Twenty-four hour urine samples were taken over three days (day before, day of and day after exercise) and measured for pyridinoline and deoxypyridinoline crosslinks. Crosslink excretion was standardised for total body bone mineral content (TBBMC) and urinary creatinine. Total body bone mineral density (and content) and body composition were measured by dual energy X-ray absorptiometry. No changes in the levels of either osteocalcin or alkaline phosphatase were seen at any time point following the exercise. Both urinary crosslinks exhibited an increase in levels on the day of the exercise and a further significant increase the day after (pyridinoline 38.7%, p = 0.05; deoxypyridinoline 42.3%, p = 0.025; median, corrected for TBBMC). There were significant negative correlations between the crosslinks, osteocalcin and body fat percentage. In conclusion, the exercise appears to have stimulated bone resorption within 32 hours of moderate exercise, but there was no measurable effect on bone formation after 32 hours. A longer study period may be necessary to detect changes in bone formation.

Absorptiometry, Photon↗
PubMed1996

Effects of isometric strength training on quadriceps muscle properties in over 55 year olds.

Changes in strength, speed and size of the quadriceps muscle have been investigated in elderly men and women after 6 months of isometric strength training. We have also indirectly investigated the role of metabolites as a stimulus for muscle hypertrophy by studying two training protocols. One thigh was trained using short, intermittent contractions (IC), while the other trained using long, continuous contractions (CC). This meant that there should be a greater metabolite change in the muscle performing CC, as the blood flow is occluded for longer. Nine subjects [eight women, mean (SE) age, 71.8 (2.9) years] were measured for contractile properties and strength before and after training, and compared to nine age-matched controls [71.5 (2.1) years]. The training group increased quadriceps strength by 48.7 (9.1)% (P < 0.005) and 53.1 (11.3)% (P < 0.005) following the IC and CC protocols, respectively. There was no change in muscle strength in the controls. Both muscles showed significant slowing after training as measured by the relaxation times and the force-frequency ratio. There were non-significant decreases in muscle fatigability after training. The control group also showed some significant decreases in fatigability and muscle speed. The training group showed significant increases in muscle (and bone) cross-sectional area of 4.0 (1.7)% and 4.9 (1.3)% following the CC and IC protocols, respectively. These increases were significantly different from the decrease observed in the control group. These findings suggest that people over the age of 55 still have the capacity to increase muscle strength and size, and that the training causes slowing of the muscle. Muscle hypertrophy does not seem to be strongly influenced by metabolite changes in this age group, as there were no differences in measurements observed between protocols.

Aged↗
PubMed1996

Hip bone mineral density is improved by high-impact aerobic exercise in postmenopausal women and men over 50 years.

Fifteen men and women (six men) between the ages of 50 and 73 years were recruited to begin keep-fit classes. They were matched for sex, age, menopausal status and mass to 15 non-exercising controls. The keep-fit classes were two to three times a week and included high-impact exercise, including step and jumping exercises specifically to load the proximal femur and spine. Proximal femur, lumbar spine and total body bone mineral density (BMD) were measured at 0 and 12 months. Urinary pyridinoline (Pyr) and deoxypyridinoline (dPyr) crosslinks were measured every 6 months to assess bone resorption. Quadriceps isometric strength was measured every 6 months. BMD increased non-significantly at the femoral neck [1.57 (0.8)%] and Wards triangle [1.97 (1.4)%], and significantly at the greater trochanter 2.21 (0.9)% (P = 0.02) in the exercise group. Femoral neck BMD decreased by -1.9(0.8)% (P = 0.049) in the control group, which was significantly different from the change in the exercise group (P = 0.009). BMD did not change at the Wards triangle or trochanter in the controls. Lumbar spine BMD did not change in either group. Total body BMD did not change in the exercise group, but decreased by -0.79 (0.3)% (P = 0.02) in the controls. Following 6 months of the exercise classes. Pyr and dPyr crosslinks were significantly reduced [-19.0 (7.2)%; P = 0.0019 and -20.0 (7.7)%; P = 0.021 respectively]. There was no significant change in crosslinks after 1 year, and no change at any time in the controls. Quadriceps strength changed by 5.4 (3.7)% in the exercise group and by -6.9 (2.5)% (P = 0.01) in the control group after 12 months, being significant between groups (P = 0.008). This study suggests that high-impact, aerobic exercise in postmenopausal women and men over 50 years old is feasible and effective at maintaining muscle strength and increasing proximal femur BMD but not spine or total body BMD.

Adipose Tissue↗
PubMed1996

In vitro activities of azithromycin, clarithromycin, erythromycin, and tetracycline against 13 strains of Chlamydia pneumoniae.

Thirteen strains of Chlamydia pneumoniae were evaluated for their in vitro susceptibilities to azithromycin, clarithromycin, erythromycin, and tetracycline. The MIC ranges were 0.125 to 0.5 micrograms/ml for azithromycin, 0.031 to 1.0 micrograms/ml for clarithromycin, 0.125 to 1.0 micrograms/ml for erythromycin, and 0.25 to 1.0 micrograms/ml for tetracycline. The ranges for the minimal lethal concentrations were 0.125 to 0.5 micrograms/ml for azithromycin, 0.031 to 1.0 micrograms/ml for clarithromycin, 0.125 to 1.0 micrograms/ml for erythromycin, and 0.25 to 1.0 micrograms/ml for tetracycline. Clarithromycin and azithromycin were the most active antibiotics against C. pneumoniae in vitro.

Anti-Bacterial Agents↗
PubMed1996

Diagnosis by AMPLICOR PCR of Chlamydia trachomatis infection in urine samples from women and men attending sexually transmitted disease clinics.

Screening of urine specimens from men for Chlamydia trachomatis infection by a commercial PCR assay (AMPLICOR C. trachomatis Test; Roche Diagnostic Systems, Inc., Branchburg, N.J.) is a sensitive and specific noninvasive diagnostic assay. Since screening of women for C. trachomatis infection with the AMPLICOR C. trachomatis Test has been limited to use with endocervical swab specimens, we conducted an evaluation of the AMPLICOR C. trachomatis Test for the detection of C. trachomatis using female urine samples and compared the results of those obtained by in vitro culture and PCR of endocervical swab specimens. For 713 men we compared the performance of AMPLICOR C. trachomatis Test with urine specimens with that of culture of urethral specimens. For specimens that were PCR positive and culture negative, two additional tests were used to resolve the discrepancies: direct fluorescent-antibody assay (DFA) of sediment from a spun endocervical specimen culture vial and major outer membrane protein-based PCR of the sediment from the endocervical specimen culture vial. Of 525 urine specimens from females, 67 (12.8%) were PCR positive, and 41 (7.8%) endocervical specimens from the 525 women were culture positive. After resolution of the discrepancies, the resolved sensitivity of the urine PCR was 93.3%, whereas the sensitivity of endocervical swab specimen culture was 67.3%. Of 468 female endocervical swab specimens, 47 (10.0%) had a positive PCR result and 33 (7.0%) were culture positive. The resolved sensitivity of the endocervical swab specimen PCR was 86%. Of 415 matched female urine and endocervical swab specimens, there were 49 confirmed infections; 30 (61.2%) specimens were positive by culture of the endocervical swab specimen, 40 (81.6%) were positive by confirmed endocervical swab specimen PCR, 43 (87.8%) were positive by confirmed urine PCR, and all 49 (100%) were positive by either endocervical swab specimen PCR or urine PCR. For men, the resolved sensitivity of the urine PCR was 88%, and the sensitivity of culture was only 50.7%. These results indicate that urine PCR is highly sensitive for the detection of C. trachomatis in both women and men and provides a noninvasive technique for routine screening for chlamydial infection.

Ambulatory Care Facilities↗
PubMed1992

Multicenter evaluation of the AntigEnz Chlamydia enzyme immunoassay for diagnosis of Chlamydia trachomatis genital infection.

To evaluate the AntigEnz Chlamydia enzyme immunoassay (EIA) (Baxter/Bartels, Issaquah, Wash.), we studied 320 men and 1,209 women attending clinics for sexually transmitted diseases in Baltimore, San Francisco, and Seattle. At examination, two separate swabs were obtained from each patient, one for chlamydial culture and one for EIA. Cervical samples were collected from women, and urethral samples were collected from men. The prevalence of chlamydial infection by culture was 9% in Baltimore (n = 532), 11% in Seattle (n = 500), and 9% in San Francisco (n = 497). To resolve specimens with discrepant culture and EIA results, the EIA transport buffer was centrifuged and the resuspended pellet was stained by direct immunofluorescence to determine whether elementary bodies were present. Overall sensitivity of the AntigEnz Chlamydia assay compared with culture was 87% in men and 86% in women, and overall specificities were 94 and 97%, respectively. Differences between centers were seen, with sensitivities ranging from 76% among men and 79% among women in Seattle to 100% among men and 95% among women in Baltimore. With a true positive considered to be either a culture-positive or an EIA- and direct immunofluorescence-positive specimen, the revised sensitivity was 91% in men and 88% in women. Overall revised specificity was 99% in both men and women. We conclude that in this high-prevalence population, the sensitivity and specificity of this assay compare favorably with those of other noncultural antigen detection tests for the diagnosis of chlamydial genital infection.

Antigens, Bacterial↗
PubMed1983

Host recognition of fetal antigens: do they induce specific antibodies?

The purpose of this study was to ascertain whether the protection afforded to adult mice against the induction and growth of 3-methylcholanthrene-induced tumours by prior exposure to syngeneic fetal cells has an immunological basis. Adult CBA mice were inoculated with fetal cells according to a variety of protocols and the sera were tested for their ability to bind to fetal and adult tissue cells, using a staphylococcal protein A binding assay. All 10 sera tested showed some degree of binding though this varied from strong to weak, and there was some cross-reactivity with adult thymic cells but relatively little with adult spleen cells. Absorption studies were carried out with one of these sera and with two others raised against testicular and thymic cells, respectively. The absorption patterns obtained so far suggest that fetal cells possess at least three, and possibly up to five, distinct antigens. Although none of the anti-fetal sera were produced with a sensitizing protocol identical with that used in in vivo protection, some of them were so close as to suggest that protection is associated with, and perhaps causally related to, these IgG antibodies. The in vitro evidence presented here, together with the in vivo data of P. B. Medawar & R. Hunt, shows that antigens are shared between fetal cells and adult thymic and testicular cells. It therefore lends support to the notion that the production of a vaccine against anaplastic neoplasms, using immunogens derived from adult tissues, is within the realms of possibility.

Animals↗
PubMed1976

Continuous Fetal Scalp and Carotid Artery Oxygen Tension Monitoring in the Sheep.

Fetal scalp and carotid PO2 were recorded continuously by polargraphic oxygen electrodes at several levels of maternal oxygenation. The results were compared to measurements obtained by intermittent blood samples using the radiometer blood gas analyzer. There was a good correlation between the PO2 values measured by the implanted oxygen electrodes and by conventional analyses of blood samples collected anaerobically. Electrode measurements differed from the control radiometer values by a mean of +/- 1.2 mmHg; 2 SD= +/- 2.50. Scalp PO2 recordings were lower but paralleled the carotid recordings under varying degrees of maternally inspired O2 concentrations. Thus scalp PO2 levels reflect closely those in the central fetal circulation. Administration of 95% O2 to the mother resulted in a 27% increase of scalp PO2 and a 29% increase in the carotid artery PO2 when compare to room air.

Animals↗
PubMedDate not supplied

Gene typing of Chlamydia trachomatis by polymerase chain reaction and restriction endonuclease digestion.

A portion of the major outer membrane protein (MOMP) gene from 15 Chlamydia trachomatis serovars was amplified by polymerase chain reaction (PCR) and the product was analyzed by restriction fragment length polymorphism (RFLP). A set of primers was used to amplify an 871 base pair gene fragment encompassing the 4 hypervariable regions of MOMP. AluI digestion of the product gave distinctive patterns for the 15 serovars as demonstrated on silver-stained polyacrylamide gels. A triple digest with EcoRI, HinfI, and HpaII allowed improved discrimination between closely related serovars (C, H, I, J, L3). PCR and RFLP were used to type 50 wild-type clinical isolates and results were compared to results of the solid-phase enzyme immunoassay typing method. These isolates represented the most prevalent genital serovars (D, E, F, K, I and J) in the local sexually transmitted diseases clinic population. For specimens containing 1 serovar, the results of the two methods were similar for 42 samples and discordant for 1 sample. In addition, two samples showed evidence of mixed infection with two serovars as identified by both methods. Five additional specimens contained two serovars, as shown by one or both methods. In all five such specimens, the two typing methods agreed on at least one of the two serovars. For both single and multiple serovar specimens, there was concordance between the two typing methods for 16/17 E serovars, 8/9 D serovars, 8/8 F serovars, 7/7 I serovars, 7/7 J serovars, 5/8 K serovars, and 0/2 G serovars.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Outer Membrane Proteins↗