Search PubMed⌕ Search

Biomedical subjects

T J Ryan

Publications and source records attributed to T J Ryan.

At least 73 records · Page 4Linked to original sources
PubMed1999

The quality of life in acne: a comparison with general medical conditions using generic questionnaires.

Skin diseases such as acne are sometimes thought of as unimportant, even trivial, when compared with diseases of other organ systems. To address this point directly, validated generic questionnaires were used to assess morbidity in acne patients and compare it with morbidity in patients with other chronic diseases. For 111 acne patients referred to a dermatologist, quality of life was measured using the Dermatology Life Quality Index, Rosenberg's measure of self-esteem, a version of the General Health Questionnaire (GHQ-28) and the Short Form 36 (SF-36). Clinical severity was measured using the Leeds Acne Grade. Population quality of life data for the SF-36 instrument were available from a random sample of adult local residents (n = 9334) some of whom reported a variety of long-standing disabling diseases. All quality of life instruments showed substantial deficits for acne patients that correlated with each other but not with clinically assessed acne severity. The acne patients (a relatively severely affected group) reported levels of social, psychological and emotional problems that were as great as those reported by patients with chronic disabling asthma, epilepsy, diabetes, back pain or arthritis. Acne is not a trivial disease in comparison with other chronic conditions. This should be recognized in the allocation of health care resources.

Acne Vulgaris↗
PubMed1999

Stress echocardiography in hyperthyroidism.

Exertion symptoms occur frequently in subjects with hyperthyroidism. Using stress echocardiography, exercise capacity and global left ventricular function can be assessed noninvasively. To evaluate stress-induced changes in cardiovascular function, 42 patients with untreated thyrotoxicosis were examined using exercise echocardiography. Studies were performed during hyperthyroidism, after treatment with propranolol, and after restoration of euthyroidism. Twenty-two healthy subjects served as controls. Ergometry was performed with patients in a semisupine position using a continuous ramp protocol starting at 20 watts/min. In contrast to control and euthyroidism, the change in end-systolic volume index from rest to maximal exercise was lower in hyperthyroidism. At rest, the stroke volume index, ejection fraction, and cardiac index were significantly increased in hyperthyroidism, but exhibited a blunted response to exercise, which normalized after restoration of euthyroidism. Propranolol treatment also led to a significant increase of delta (delta) stroke volume index. Maximal work load and delta heart rate were markedly lower in hyper- vs. euthyroidism. Compared to the control value, systemic vascular resistance was lowered by 36% in hyperthyroidism at rest, but no further decline was noted at maximal exercise. The delta stroke volume index, delta ejection fraction, delta heart rate, and maximal work load were significantly reduced in severe hyperthyroidism. Negative correlations between free T3 and diastolic blood pressure, maximal work load, delta heart rate, and delta ejection fraction were noted. Thus, in hyperthyroidism, stress echocardiography revealed impaired chronotropic, contractile, and vasodilatatory cardiovascular reserves, which were reversible when euthyroidism was restored.

Adult↗
PubMed1999

The gender paradox.

Explore the source record for details and available documents.

Coronary Disease↗
PubMed1998

Modelling the regional dynamics and management of bovine tuberculosis in New Zealand cattle herds.

A previous model addressed the within-herd transmission of bovine Tb (Mycobacterium bovis) in New Zealand cattle herds. This complementary model considers transmission between herds, in an area of New Zealand's North Island (the Waikato) largely free from wildlife reservoirs. The model is used to account for the observed pattern of Tb breakdowns and to assess the likely impact of changes in management on the percentage of herds on movement control between 1988 and 1993 (an average of 0.76% in the Waikato region). It partitions the region into two sub-areas: one small, with significant infection from wildlife; the other much larger and lacking external sources of infection. The observed pattern of herd breakdowns (in different parts of the Waikato and in the region as a whole) could be accounted for in the model by infection from wildlife reservoirs in the southern sub-area (Waitomo) and infection due to movement of cattle from infected but undiagnosed herds to uninfected herds throughout the whole region. During the above period, the model suggests that about 0.8% of herds became infected each year, that most new infections (81% of the total) occurred between herds in the larger sub-area, and that about 13% of the total occurred through infection from wildlife in the smaller sub-area. The whole situation appears to be in a state of near-neutral balance (even without input of new infection), with removal through testing of new infections almost exactly balancing the rate of infection by between-herd movement. Therefore, if the external input is removed, the number of infected herds and of herds of movement control in the whole region declines so slowly that the decline is almost undetectable. Other management changes had a more dramatic effect--particularly, reducing the testing interval to a maximum of 1 year in the whole district. This also appeared to be a necessary condition for achieving < or = 0.2% herds on movement control within 10 years (whatever other strategies were employed). The greatest reduction in the percentage of herds on movement control came from yearly testing plus a 50% reduction in infection from wildlife. A further but smaller additional improvement was gained by reducing cattle movements throughout the region by 50%.

Animal Husbandry↗
PubMed1998

Intraspecific heterochrony and life history evolution: decoupling somatic and sexual development in a facultatively paedomorphic salamander.

Morphological features such as size and shape are the most common focus in studies of heterochronic change. Frequently, these easily observed and measured features are treated as a major target of selection, potentially ignoring traits more closely related to fitness. We question the primacy of morphological data in studies of heterochrony, and instead suggest that principal sources of fitness, such as life history characteristics, are not only the chief targets of selection, but changes in them may necessitate changes in other (subordinate) elements of the organism. We use an experimental approach to investigate the timing of metamorphosis and maturation in a facultatively paedomorphic salamander, Ambystoma talpoideum. We determine that individuals possessing the well-known paedomorphic phenotype are peramorphic with regard to maturation, through the process of predisplacement (an earlier onset of maturation). Combining the well studied ecology of dimorphic A. talpoideum populations with theories of heterochronic mechanisms and life history evolution, we conclude that age at maturation is the principal target of selection and that morphological changes are secondary effects. Increased attention to the intimate connection between life history evolution and heterochrony is the most promising route to a better understanding of both.

Ambystomatidae↗
PubMed1998

Operator volume and outcomes in 12,998 percutaneous coronary interventions. Northern New England Cardiovascular Disease Study Group.

OBJECTIVES: We sought to determine whether there is a relation between operator volume and outcomes for percutaneous coronary interventions (PCIs). BACKGROUND: A 1993 American College of Cardiology/American Heart Association task force stated that cardiologists should perform > or = 75 procedures/year to maintain competency in PCIs; however, there were limited data available to support this statement. METHODS: Data were collected from 1990 through 1993 on 12,988 PCIs (12,118 consecutive hospital admissions) performed by 31 cardiologists at two hospitals in New Hampshire and two in Maine and one hospital in Massachusetts supporting these procedures. Operators were categorized into terciles based on annualized volume of procedures. Univariate and multivariate regression analyses were used to control for case-mix. Successful outcomes included angiographic success (all lesions attempted dilated to < 50% residual stenosis) and clinical success (at least one lesion dilated to < 50% residual stenosis and no adverse outcomes). In-hospital adverse outcomes included coronary artery bypass graft surgery (CABG), myocardial infarction (MI) and death. RESULTS: After adjustment for case-mix, higher angiographic (low, middle and high terciles: 84.7%, 86.1% and 90.3%, p-trend 0.006) and clinical success rates (85.8%, 88.0% and 90.7%, p-trend 0.025), with fewer referrals to CABG (4.54%, 3.75% and 2.49%, p-trend <0.001), were seen as operator volume increased. There was a trend toward higher MI rates for high volume operators (2.00%, 1.98% and 2.57%, p-trend 0.06); all terciles had similar in-hospital mortality rates (1.09%, 0.96% and 1.05%, p-trend 0.8). CONCLUSIONS: There is a significant relation between operator volume and outcomes in PCIs. Efforts should be directed toward understanding why high volume operators are more successful and encounter fewer adverse outcomes.

Angioplasty, Balloon, Coronary↗
PubMed1998

Dermal oedema assessed by high frequency ultrasound in venous leg ulcers.

Oedema is considered a key pathogenic factor in the development of venous leg ulcers. The purpose of this study was to determine the localization of oedema in legs with ulcers. Twelve patients with 13 venous leg ulcers (one bilateral), with a duration of 7-18 months, were examined by high-frequency B-mode ultrasound scanner. This was performed at three sites in the leg (low, middle and upper sites of the lower leg). In the same group of patients, the legs without ulcers were used as controls. The echogenicity and the thickness of the whole dermis were quantified by digital image analysis; the echogenicities of the upper (papillary) and lower portions of the dermis were measured. In the upper site no significant difference was found between the legs with ulcers and controls. In the middle and low sites of legs with ulcers, the dermal echogenicities were 34% and 64% (P < 0.01) less than those in controls, and the dermal thicknesses were 0.4 mm and 0.8 mm (P < 0.01) thicker than those in controls, respectively. This indicated intradermal oedema existing in the lower part (gaiter area) of the legs with ulcers. The ratios of low echogenic pixels in the upper and lower portions of the dermis, in the middle and low sites of legs with ulcers, were 0.5 and 0.9 (P < 0.05 and P < 0.01), respectively, higher than those in controls, suggesting the papillary dermis as a preferential site of oedema formation. The present study demonstrates that in the low sites of legs with ulcers, a marked increase in oedema was seen in the papillary dermis. This may add to the understanding of the origin of leg ulcers in the gaiter area of the leg.

Aged↗
PubMed1998

Laser Doppler imaging of skin microcirculation.

Laser Doppler imaging (LDI), a new technique which allows measurement of skin blood perfusion at a distance from the skin surface, was assessed methodologically in healthy volunteers. Each skin LDI value was based on virtually real-time measurements obtained from a number of discrete measuring sites. In scans made along the circumference of the lower arm, valid figures for LDI (as distinct from no output at all) were obtained in 8/8 measurements at 0 degrees inclination, and in 16/16 measurements at 7 degrees, 14 degrees, 22 degrees, 30 degrees and 38 degrees, respectively. Beyond this inclination a numerical output was obtained in only 9/16 of measurements at an inclination of 48 degrees, in 7/16 at 69 degrees, and in no more than 1/16 at 90 degrees. Values obtained at angles of inclination greater than 38 degrees fell within the relatively narrow range of values obtained at lesser angles of inclination. The findings are of interest since measuring sites of clinical importance may not be flat. Variability of measurement (coefficient of variation in per cent) was studied in the lower leg by performing LDI and conventional laser Doppler flowmetry (LDF) concomitantly. The coefficient of variation for measurements in one subject at rest was 13% for LDI vs. 19% for LDF, the corresponding interindividual coefficient of variation values being 25% vs. 28%. In response to heating, finger pulp perfusion increased by 55% as measured by LDI (p = 0.0051) and by 44% (p = 0.0756) as measured by LDF. In summary, the findings contribute to the validation of LDI for skin perfusion measurement.

Adolescent↗
PubMed1998

The veno-arteriolar reflex in venous leg ulcer patients studied by laser Doppler imaging.

Posture-induced microcirculatory changes in the lower leg were studied in venous leg ulcer patients and in control subjects by means of laser Doppler imaging (LDI), a technique which allows almost real-time mapping of the perfusion from a distance, each perfusion value constituting the mean of a number of measurements at separate sites. LDI values for intact skin with the subject supine were 0.39 (0.32, 0.47) V [geometric mean (gm -SD, gm +SD)] and 0.32 (0.15, 0.70) V in two age groups of controls and 0.91 (0.66, 1.24) V in patients (NS). Values were 2.04 (1.25, 3.35) V for skin at the ulcer margin, and 1.44 (0.72, 2.88) V in the ulcer proper. With the lower leg passively dependent, lower LDI values were obtained at all sites in all groups, the reduction in intact skin value being 62 +/- 11% (arithmetic mean +/- SD) (p < 0.01) in the younger controls, 43 +/- 24% (p < 0.01) in the older controls and 62 +/- 19% (p < 0.001) in the patient group, and the reduction in ulcer values being 45 +/- 27% (p < 0.05) for the margin and 52 +/- 23% (p < 0.001) for the ulcer proper. Thus, a high degree of postural vasoconstriction was present overall, even in the ulcer itself. Vasomotor tone in the skin of the lower leg was assessed by topical application of methyl nicotinate, a vasodilator. The skin perfusion value (supine position, no stimulus) was 71 +/- 31% (p < 0.01) of the drug-induced (assumed peak) hyperaemia value [0.60 (0.30, 1.10) V] in patients and 24 +/- 25% (p < 0.001) of the hyperaemia value (1.30 (0.64, 2.62) V] in the controls. It would appear that in ulcer patients the veno-arteriolar reflex, despite being comparable in magnitude to that in controls, may nonetheless be insufficient to reduce tone during dependency to a level similar to that in healthy controls.

Adult↗
PubMed1998

Management of leg ulcers.

Management of leg ulcers requires attention to a checklist of causes of delay in healing, the commonest cause of which is venous disease. Arterial disease must be excluded before fully effective management of venous disease is possible. Lymphatic failure is also worthy of attention. 'Keep moving' is an important management theme for the whole team, including the patient.

Anti-Bacterial Agents↗
PubMed1998

Characterization of human cellular gamma-glutamyl hydrolase.

A previously identified cDNA encoding a human gamma-glutamyl hydrolase was expressed in a baculovirus system. The expressed protein had molecular mass of 37 kDa. Treatment of the protein with PNGase F produced a protein of molecular mass of 30 kDa, indicating that the protein contained asparagine-linked glycosylation. Sequence analysis of the expressed protein indicated that a 24-amino-acid signal peptide had been removed. A polyclonal antibody to the expressed enzyme was used in Western blot analysis of partially purified lysates of HL-60 promyeloid leukemia cells and MCF-7 breast cancer cells. The HL-60 and MCF-7 enzymes appeared as two closely spaced bands with a molecular mass of 37 kDa. Treatment of the HL-60 enzyme with PNGase F produced a protein with a molecular mass of 30 kDa. The activities of the expressed enzyme and the enzyme from HL-60 cells were similar on methotrexate polyglutamates. Methotrexate-gamma-Glu is a poor substrate for the human enzyme relative to methotrexate gamma-Glu2-5. During hydrolysis of methotrexate-gamma-Glu4, all possible pterin-containing cleavage products (methotrexate and methotrexate-gamma-Glu1-3) appear. The results demonstrated that the human enzyme cleaves both the ultimate and penultimate gamma-linkages of methotrexate polyglutamates. Glutamate was released as either glutamic acid or gamma-Glu2. Longer chain species of gamma-Glun>2 were not observed. Inhibition by iodoacetic acid suggested that both the expressed enzyme and the HL-60 enzyme may contain a catalytically essential cysteine. These results indicate that the identified cDNA encodes the intracellular gamma-glutamyl hydrolase found in a variety of human tumor cells and that the baculovirus-expressed enzyme is a suitable model for further structural and enzymatic studies.

Animals↗