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Biomedical subjects

P Kelly

Publications and source records attributed to P Kelly.

At least 163 records · Page 9Linked to original sources
PubMed1994

What factors predict discrepancies between self and observer ratings of depression?

This study used a matched clinician and self-rating scale, the Inventory for Depressive Symptomatology (IDS; Rush et al., 1986), in the assessment of 48 patients meeting DSM-III-R criteria for non-psychotic major depressive disorder. Patients generally rated their symptoms as more severe than the clinician, but differences between the self and clinician rating (the delta-IDS) were significantly correlated with non-endogenous depressive subtype, higher levels of neuroticism and dysfunctional attitudes, and lower self-esteem. Multiple linear regression analysis which controlled for severity of depression demonstrated that whilst neuroticism, dysfunctional attitudes and self-esteem accounted for 48.5% of the variance in delta-IDS, the variable accounting for most of the variance was low self-esteem (47.9%).

Adult↗
PubMed1994

Excimer laser correction of myopic astigmatism.

The excimer laser allows the controlled ablation of corneal tissue to correct refractive error. By using a combination of spherical and slit apertures, it is possible to correct both myopia and astigmatism. We report the results of 139 consecutive eyes that had photoastigmatic refractive keratectomy (PARK) for myopic astigmatism (myopia < or = -15.00 diopters [D] with astigmatism < or = -6.00 D) and compare these results with 107 consecutive and concurrent eyes that received photorefractive keratectomy (PRK) for myopia (< or = -15.00 D). The same excimer laser was used by 27 different surgeons. All patients were followed for at least three months. In the PARK group, 68% were within +/- 1.00 D at six months and 77% were within +/- 2.00 D. In the PARK group, these figures were 87% and 97%, respectively. Uncorrected visual acuity of 20/40 or better was achieved in 72% of PARK and 90% of PRK patients at six months. Minor adverse reactions occurred in 6% of PARK and 11% of PRK patients. No significant surgeon effect was seen. Photoastigmatic refractive keratectomy provides a realistic approach to the surgical correction of myopic astigmatism and is comparable to PRK in safety and efficacy.

Adult↗
PubMed1994

Biochemical and pharmacological factors causing induction and suppression of germination of Trichosporon beigelii.

Trichosporon beigelii is an emerging fungal pathogen, which is morphologically characterized by blastoconidia, arthroconidia and hyphae. The non-hyphal forms of T. beigelii germinate to form hyphae in plasma in vitro and in tissues in vivo, suggesting possible pathophysiological significance of this process. Little is known, however, about the mechanisms of germination of T. beigelii. We therefore studied relevant biochemical and pharmacological factors that may regulate germination of T. beigelii. Germination was significantly enhanced by temperature at 37 degrees C, chemically defined cell culture media such as RPMI-1640, plasma, physiological pH, N-acetylglucosamine and proline. N-acetylglucosamine was equivalent to proline in inducing germination. Germination was suppressed by high concentrations of glucose, increasing inocula, low pH, and amphotericin B at achievable serum concentrations. Thus, many of the factors regulating germination of T. beigelii appear to be similar to those for Candida albicans.

Amino Acids↗
PubMed1994

Exercise-induced fall in insulin: mechanism of action at the liver and effects on muscle glucose metabolism.

To determine the importance of the fall in insulin on whole body glucose fluxes and muscle glucose metabolism during exercise, dogs ran on a motorized treadmill for 90 min at a moderate work rate with somatostatin (SRIF) infused to suppress insulin and glucagon and basal (B-INS; n = 6 dogs) or exercise-stimulated (S-INS; n = 8 dogs) insulin replacement. The fall in insulin during exercise potently stimulates glucose production at least in part by potentiating the actions of glucagon. To assess the hepatic effects of insulin in the absence of its potentiating effect on glucagon action, glucagon levels were not restored during SRIF infusion. At least 17 days before experimentation, dogs underwent surgery for chronic placement of sampling (carotid artery and femoral vein) and infusion (inferior vena cava and portal vein) catheters. Hindlimb blood flow was assessed by placement of a Doppler flow cuff on the external iliac artery. Whole body glucose production (Ra) and disappearance (Rd) were assessed with [3-3H]glucose, and hindlimb glucose uptake and metabolism were assessed with arterial-venous differences and [U-14C]glucose. Insulin levels were 69 +/- 6 and 61 +/- 7 pM at rest in B-INS and S-INS and 62 +/- 10 and 41 +/- 6 pM at 30 min of exercise. Glucose levels were clamped at euglycemic levels with an exogenous glucose infusion during rest and exercise in both groups. Exercise-induced increases in Ra, Rd, hindlimb glucose uptake, and hindlimb oxidative and nonoxidative glucose metabolism were not affected by maintenance of basil insulin levels during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1994

Dose-response of chronic beta-blocker treatment in heart failure from either idiopathic dilated or ischemic cardiomyopathy. Bucindolol Investigators.

BACKGROUND: Small-scale clinical investigations have demonstrated that single doses of beta-blocking agents can improve left ventricular function in heart failure from idiopathic dilated cardiomyopathy (IDC). The purpose of this multicenter clinical trial was to determine the dose-effect characteristics of beta-blockade in a heart failure population that includes ischemic dilated cardiomyopathy (ISCD). METHODS AND RESULTS: Bucindolol is a nonselective beta-blocking agent with mild vasodilatory properties. One hundred forty-one subjects with class II or III heart failure, left ventricular ejection fraction (LVEF) < or = 0.40, and background therapy of angiotensin-converting enzyme inhibitors, digoxin, and diuretics were given an initial challenge dose of bucindolol 12.5 mg. One hundred thirty-nine subjects (99 with IDC, 40 with ISCDC) tolerated challenge and were randomized to treatment with placebo or bucindolol 12.5 mg/d (low dose), 50 mg/d (medium dose), or 200 mg/d (high dose). At the end of 12 weeks, left ventricular function and other parameters were measured and compared with baseline values. There was a dose-related improvement in left ventricular function in bucindolol-treated subjects. In the high-dose bucindolol group, radionuclide-measured LVEF improved by 7.8 EF units (%) compared with 1.8 units in the placebo group (P < .05), and compared with the placebo group, a greater percentage of subjects had an increase in LVEF by > or = 5 units. In contrast, all three bucindolol doses prevented deterioration of myocardial function as defined by an LVEF decline of > or = 5 units. CONCLUSIONS: In heart failure from systolic dysfunction, beta-blockade with bucindolol produces a dose-related improvement in and prevents deterioration of left ventricular function.

Adrenergic beta-Antagonists↗
PubMed1994

Expediting the turnaround of radiology reports: use of total quality management to facilitate radiologists' report signing.

OBJECTIVE: The purpose of this study was to determine whether total quality management techniques could be used to speed radiologists' performance on the task of signing reports. SUBJECTS AND METHODS: Total quality management represents a group of tools that can be used to improve the functioning of complex processes in the workplace. The steps involved in our total quality management project were as follows: (1) commit to improving radiologists' performance, (2) commission an interdisciplinary study team, (3) propose hypotheses for the causes of signing delays, (4) identify the key issues constraining performance (Pareto analysis), (5) intervene to correct systematic problems in a test system, (6) evaluate the results of intervention on radiologists' report signing performance, and (7) hold the gains achieved by the intervention. An interdisciplinary study team identified five key obstacles to prompt signing of reports: (1) radiologists' absence from the department when reports were available for signing (e.g., nights and weekends), (2) dysfunctional hand-off between transcriptionist and radiologist, (3) requirement that a fellow or resident sign before a staff radiologist, (4) lack of a system for signing by proxy (if primary radiologist is away), (5) perceived lack of impact of signed report on clinical decision making. RESULTS: Interventions included (1) providing home computer terminals, (2) implementing a buddy system for proxy signing, (3) eliminating the requirement for a signature from a fellow or resident, (4) teaming groups of radiologists with specific transcriptionists, and (5) streamlining transcription service. When these enhancements were used in a test system, the mean time required to sign reports decreased 59% from 26.0 +/- 8.4 hr (mean +/- standard error) in the baseline period to 10.6 +/- 2.9 hr (in the enhanced period, p = .05). CONCLUSION: We conclude that total quality management methods can accelerate radiologists' signing of reports.

Authorship↗
PubMed1993

Prediction of osteoporotic fractures by postural instability and bone density.

OBJECTIVE: To investigate the utility of risk factors such as bone mineral density, lifestyle, and postural stability in the prediction of osteoporotic fractures. DESIGN: Longitudinal, epidemiological, and population based survey. SETTING: City of Dubbo, New South Wales. SUBJECTS: All residents of Dubbo aged > or = 60 on 1 January 1989. MAIN OUTCOME MEASURE: Incidence of fracture for individual subjects. RESULTS: The overall incidence of atraumatic fractures in men and women was 1.9% and 3.1% per annum respectively. The predominant sites of fracture were hip (18.9%), distal radius (18.5%), ribs and humerus (11.9% in each case), and ankle and foot (9.1% and 6.6% respectively). Major predictors of fractures in men and women were femoral neck bone mineral density, body sway, and quadriceps strength. Age, years since menopause, height, weight, and lifestyle factors were also correlated with bone mineral density and body sway and hence were indirect risk factors for fracture. Discriminant function analysis correctly identified 96% and 93% (sensitivities 88% and 81%) of men and women, respectively, who subsequently developed atraumatic fractures. Predictions based on this model indicated that a woman with a bone mineral density in the lowest quartile in the hip together with high body sway had a 8.4% probability of fracture per annum. This represented an almost 14-fold increase in risk of fracture compared with a woman in the highest bone mineral density quartile with low postural sway. An individual with all three predictors in the "highest risk" quartile had a 13.1% risk of fracture per annum. CONCLUSIONS: Bone mineral density, body sway, and muscle strength are independent and powerful synergistic predictors of fracture incidence.

Aged↗
PubMed1993

Prevention of corticosteroid osteoporosis. A comparison of calcium, calcitriol, and calcitonin.

BACKGROUND: Prolonged corticosteroid therapy increases the risk of osteoporosis and fracture. We studied whether corticosteroid-induced osteoporosis could be prevented by treatment with calcium, calcitriol (1,25-dihydroxyvitamin D3), and calcitonin. METHODS: One hundred three patients starting long-term corticosteroid therapy were randomly assigned to receive 1000 mg of calcium per day orally and either calcitriol (0.5 to 1.0 microgram per day orally) plus salmon calcitonin (400 IU per day intranasally), calcitriol plus a placebo nasal spray, or double placebo for one year. Data on treatment efficacy were available for 92 of these patients. Bone density was measured every four months for two years by photon absorptiometry. There were no significant differences between groups with respect to age, underlying disease, initial bone density, or corticosteroid dose during the first year. RESULTS: Calcitriol (mean dose, 0.6 microgram per day), with or without calcitonin, prevented more bone loss from the lumbar spine (mean rates of change, -0.2 and -1.3 percent per year, respectively) than calcium alone (-4.3 percent per year, P = 0.0035). Bone loss at the femoral neck and distal radius was not significantly affected by any treatment. In the second year, lumbar bone loss did not occur in the group previously treated with calcitonin plus calcitriol (+0.7 percent per year), but it did occur in the group given calcium alone (-2.3 percent per year). The calcitriol group also lost lumbar bone (-3.6 percent per year) but received more corticosteroid in the second year than the other two groups. CONCLUSIONS: Calcitriol and calcium, used prophylactically with or without calcitonin, prevent corticosteroid-induced bone loss in the lumbar spine.

Adolescent↗
PubMed1993

Comparison of excimer laser treatment of astigmatism and myopia. The Excimer Laser and Research Group.

OBJECTIVE: To assess the safety and efficacy of excimer laser treatment of myopic astigmatism and to compare this with the excimer laser treatment of myopia. DESIGN: A prospective, open study of consecutive patients having excimer laser treatment of myopic astigmatism or myopia. SETTINGS: Patients were recruited from 18 private ophthalmic practices. PATIENTS: Fifty-four eyes received treatment for astigmatism and 66 eyes for myopia. One patient was lost to follow-up, and another underwent an ineffective ablation. INTERVENTIONS: A VISX Twenty/Twenty excimer laser was used to perform either photoastigmatic refractive keratectomy or photorefractive keratectomy. MAIN OUTCOME MEASURES: Refraction and visual acuity with and without correction were assessed preoperatively and postoperatively. RESULTS: At 6 months, 17 (85%) of the 20 patients receiving photoastigmatic refractive keratectomy were within 1 diopter of plano refraction, and 19 (95%) of 20 had uncorrected visual acuity of 6/12 (20/40) or better. For patients receiving photorefractive keratectomy, these figures were 28 (88%) of 32 patients and 28 (88%) of 32 patients, respectively. CONCLUSIONS: Excimer laser surgery offers an effective option in the treatment of myopic astigmatism.

Adult↗
PubMed1993

Prevention of corticosteroid bone loss.

Prolonged corticosteroid therapy is known to result in an increased risk of osteoporotic fracture, probably as a consequence of enhanced bone resorption and depressed bone formation. We examined the effects of prophylactic treatment with 1,25-dihydroxyvitamin D3 (calcitonin) and nasal salmon calcitonin on corticosteroid-induced bone loss in 103 patients being treated with long-term corticosteroids for the first time in a randomized, double-masked prospective study. Patients were randomly allocated to one of three groups receiving either calcium supplementation alone, calcium plus calcitriol, or calcium plus calcitriol and nasal salmon calcitonin. Treatment was given for 12 months. Bone mineral density (BMD) was measured every 4 months by dual-photon absorptiometry in the lumbar spine and femoral neck. Calcium supplementation alone did not prevent bone loss at either site. In the lumbar spine calcitriol, with or without nasal calcitonin, significantly reduced bone loss (p < 0.0001). Neither calcitriol alone nor calcitriol with calcitonin prevented bone loss at the femoral neck. These data suggest that treatment with calcium and calcitriol, or with calcium and intranasal calcitonin, greatly reduced or prevented corticosteroid-induced bone loss in the lumbar spine.

Adrenal Cortex Hormones↗
PubMed1993

Lysis of erythrocytes by exposure to CW ultrasound.

The threshold for lysis of erythrocytes suspended at concentrations of 0.5-1% in saline or plasma in rotating cylindrical exposure vessels is approximately spatial peak intensities of 2 W/cm2 at 1 MHz continuous wave (CW). Results of a series of experiments in which cell concentration, viscosity and gas composition of the suspending medium and rotation speed of the exposure vessel were varied combined with observations of sonoluminescence are all consistent with a hypothesis that cells are lysed by inertial (transient) acoustic cavitation. For the proposed mechanism to operate in cell suspensions, it is necessary that bubbles be brought into contact with the cells. Rotation of the chamber recycles bubbles that are driven by radiation forces to the far wall of the chamber in a matter of milliseconds. The physical and chemical properties of the wall of the chamber appear to be important as stabilizing sites for nuclei that serve as seeds for cavitation events.

Animals↗
PubMed1993

DNA fingerprints of Mycobacterium tuberculosis do not change during the development of rifampicin resistance.

Drug-resistant tuberculosis has become a major public health problem. Resistance to rifampicin probably arises through mutations in the mycobacterial RNA polymerase. Patients may acquire rifampicin resistant tuberculosis by three mechanisms: (1) infection with a resistant organism, (2) selection of a sub-population of resistant organisms that remain contained whilst the more virulent wild type is present, (3) mutations within the population of bacilli causing the original infection. Sequential isolates of Mycobacterium tuberculosis were collected from 2 patients who developed rifampicin resistance whilst on treatment. One patient was immunosuppressed with HIV-infection; in the other patient the original isolate was also resistant to isoniazid. DNA fingerprinting techniques were used to type the isolates. No differences were found between the fingerprints of isolates from before and after the development of resistance. These data suggest that the third of the mechanisms listed above was responsible for the acquisition of rifampicin resistance in these 2 patients.

Adult↗
PubMed1993

Bone mass and ageing.

Bone can be divided into two kinds of tissue, cortical and trabecular bone. The skeleton comprises approximately 80% cortical bone, mainly in peripheral bones, and 20% trabecular bone, mainly in the axial skeleton. Bone density increases with skeletal growth to a peak in late adolescence or early adulthood. Bone loss subsequently occurs with ageing in both sexes, and in females accelerated loss occurs at the menopause. The risk of osteoporotic fracture in later life is the result of peak bone mass achieved at skeletal maturity and subsequent age-related and postmenopausal bone loss. Peak bone mass is largely genetically determined but is also influenced by environmental factors such as dietary calcium and physical activity. Bone loss with ageing occurs at different rates and different times in different skeletal sites. Femoral neck bone loss probably occurs in a linear fashion throughout life from early adulthood but may be accelerated at the menopause. Spinal bone loss may commence before the menopause but is rapidly increased in the immediate postmenopausal years. Bone strength is directly related to bone density, but the loading force is also relevant to risk of fracture.

Aging↗
PubMed1993

Chemotherapy of African AIDS diarrhoea: a preliminary study.

OBJECTIVE: To determine whether combined chemotherapy with tinidazole, thiabendazole and cotrimoxazole is more effective than placebo in treatment of AIDS diarrhoea in Zambia. DESIGN: Single-blind prospective comparison in consecutive patients, randomized alternately to placebo or chemotherapy. SETTING: A district hospital in Zambia. PATIENTS: Sixty-four HIV-seropositive patients with chronic diarrhoea were considered for inclusion in the study. Of these, 25 patients were not eligible for randomization (in 13 cases because of spontaneous remission); 11 were randomized, but excluded from the analysis (seven failed to attend for a scheduled visit and four died), leaving 28 patients who completed the study. MAIN OUTCOME MEASURES: Proportion of diarrhoea-free days in the 7 days following treatment, as determined by daily stool counts. RESULTS: There were 38 diarrhoea-free days out of 89 (43%) in the placebo group, and 39 out of 72 (54%) in the chemotherapy group; this difference was not statistically significant. CONCLUSIONS: The high level of spontaneous remission probably indicates a natural fluctuation in stool frequency and demonstrates the need for placebo-controlled studies in any assessment of therapy for AIDS diarrhoea. Our findings do not allow us to conclude that the chemotherapy used is ineffective, since the number of patients was low, but will help in our understanding of the natural history of the disorder and the design of future studies.

AIDS-Related Opportunistic Infections↗
PubMed1993

The response of implanted dual chamber pacemakers to 50 Hz extraneous electrical interference.

Twenty-two patients with dual chamber pacemakers with interchangeable lead configuration were exposed to 50 Hz electromagnetic interference. Current, at corporeal levels from 0-600 microA, was applied between electrodes on shoulders and feet using a bedside injection unit. Pacemaker behavior was monitored with telemetered event markers and intracardiac electrograms. In bipolar mode, noise reversion mode was induced in all except two Medtronic units at high (> 170 microA) levels of corporeal current. In the Intermedics, Siemens Pacesetter, and Telectronics models, onset of noise reversion mode was preceded by a window of inappropriate function, characterized by rate acceleration due to atrial malsensing, or pacemaker inhibition due to ventricular malsensing. In unipolar mode, pacemaker malfunction occurred at much lower current levels. Inappropriate behavior preceded the onset of protective noise reversion mode. During current injection, all pacemakers could be interrogated and reprogrammed, and intracardiac telemetry was reliably obtained except in two Medtronic units at high current levels. No pacemaker was reset by the electrical interference, and no cross-talk was seen. Use of bipolar mode confers a high degree of protection from extraneous electrical interference, but in unipolar mode pacemakers may be inhibited by small amounts of corporeal current, potentially encountered in every day life. The current injection unit allows safe, controllable, and quantifiable investigation of the effects of the electric field induced by a current on implanted pacemakers. Telemetry of annotated intracardiac signals during electromagnetic interference clarifies observations of pacemaker acceleration and inhibition.

Adult↗
PubMed1993

A comparison of 10 MHz ultrasound and 201-thallium/99m-technetium subtraction scanning in primary hyperparathyroidism.

Both high resolution (10 MHz) ultrasound and 201-thallium/99m-technetium subtraction scanning (Tl/Tc) were carried out preoperatively in 25 patients with primary hyperparathyroidism. Operative findings were the standard against which these two imaging methodologies were compared. Tl/Tc scanning showed a sensitivity of 42% and a specificity of 97%. By comparison, sensitivity of ultrasound was 38% and specificity 89%. Both techniques were positive together in nine instances and correctly localized the parathyroid adenoma in eight of these. In 44% of cases, however, both methods together failed to localize any abnormal parathyroid tissue. The ability of these modalities to localize abnormal parathyroid tissue correctly tended to vary with gland size. Where both ultrasound and Tl/Tc scans were negative, median gland size was smaller at 170 mg (range 50-2,500 mg), compared with where Tl/Tc scanning was correct (750 mg, 150-6,820 mg; P < 0.03), ultrasound was correct (960 mg, 100-6,820 mg; P < 0.03) and both techniques together were correct (980 mg, 600-6,820 mg; P = 0.002). These results suggest that neither Tl/Tc scanning or ultrasound has sufficient sensitivity or specificity to be used routinely in the preoperative evaluation of patients with primary hyperparathyroidism.

Female↗