Biomedical subjects

Greg D Gamble

Publications and source records attributed to Greg D Gamble.

27 records · Page 2Linked to original sources

PubMed2004

Auckland proliferative diabetic vitrectomy fellow eye study.

BACKGROUND: To review medical and ophthalmic findings of primary diabetic vitrectomy patients to examine indices important in progression to fellow eye surgery. METHODS: A retrospective analysis was undertaken of all diabetic patients undergoing vitreoretinal surgery at Auckland Public Hospital between January 1992 and July 1996. Kaplan-Meier survival analysis was performed along with univariate and multivariate (Cox Proportional Hazards) data analysis. RESULTS: One hundred and fourteen primary diabetic vitrectomy cases were reviewed with mean follow-up duration of 4 years. Thirty-eight per cent (n = 43) of the study group underwent fellow eye surgery at a mean time of 1.6 years after first eye surgery. Fourteen patients were already blind in the fellow eye at baseline, and five patients refused second eye surgery on intention to treat. Thus there were 62 (54%) patients with severe (surgical threshold) fellow eye disease diagnosed within the follow-up period. The presence of either tractional retinal detachment or combined rhegmatogenous/tractional retinal detachment but without vitreous haemorrhage in the presenting eye was, in this series, a risk factor for fellow eye surgery (OR 5.56; 95% CI 1.96-15.8). Maori and Pacific Islander ethnicity was significantly associated with traction retinal detachment (OR 2.23; 95% CI 1.05-4.7). At data analysis 57% (n = 60) of the study patients had died. The mean time to death was 4.3 years, with 84% of these patients having evidence of renal disease at the time of their first eye surgery. Good visual function in at least one eye was maintained in many patients. CONCLUSIONS: A substantial proportion of diabetic vitrectomy patients require fellow eye surgery. Absence of vitreous haemorrhage in the presenting eye (i.e. tractional or combined rhegmatogenous/tractional retinal detachments but without vitreous haemorrhage) was predictive of need for fellow eye surgery. The need for diabetic vitrectomy correlates with poor survival in this study population.

Adult↗

PubMed2004

Factors influencing mortality in acromegaly.

Studies of acromegaly have shown a doubling of mortality compared with the general population. With the development of new modalities of treatment, it has become important to identify prognostic factors relating to mortality. Between 1964 and 2000, 208 acromegalic patients were followed for a mean of 13 yr at Auckland Hospital. Treatment was by surgery or radionuclide pituitary implantation, and all except 27 patients received pituitary radiation. Over the duration of the study, 72 patients died at a mean age of 61 +/- 12.8 yr. Those dying were significantly older at diagnosis, had a higher prevalence of hypertension and diabetes, and were more likely to have hypopituitarism. The observed to expected mortality ratio (O/E ratio) fell from 2.6 (95% confidence interval, 1.9-3.6) in those with last follow-up GH greater than 5 microg/liter to 2.5 (1.6-3.8), 1.6 (0.9-3), and 1.1 (0.5-2.1) for those with GH less than 5, less than 2, and less than 1 microg/liter, respectively (P < 0.001). Serum IGF-I, expressed as an SD score, was significantly associated with mortality, with O/E mortality ratios of 3.5 (95% confidence interval, 2.8-4.2) for those with an SD score greater than 2, 1.6 (0.6-2.6) for those with an SD score less than 2 (normal or low levels), and 1.0 (0.1-3) for those with an SD score less than zero. When assessed by multivariate analysis, last serum GH (P < 0.001), age, duration of symptoms before diagnosis (P < 0.03), and hypertension (P < 0.04) were independent predictors of survival. If IGF-I was substituted for GH, then survival was independently related to last IGF-I SD score (P < 0.02), indicating that GH and IGF-I act equivalently as predictors of mortality. These findings indicate that reduction of GH to less than 1 microg/liter or normalization of serum IGF-I reduces mortality to expected levels.

Acromegaly↗

PubMed2003

Amino-terminal pro-C-type natriuretic peptide in heart failure.

The levels and pathophysiological role of amino terminal C-type natriuretic peptide in heart failure are unknown. The potential of plasma amino-terminal C-type natriuretic peptide (N-CNP) as a marker of cardiac function was investigated in symptomatic patients. In 305 patients with recent-onset dyspnea and/or peripheral edema, presenting to primary care, assay of plasma amino-terminal C-type natriuretic peptide and other plasma vasoactive hormones was conducted together with echocardiography. Heart failure was diagnosed in 77 (of the 305) patients by rigorous application of predefined criteria. Plasma amino-terminal C-type natriuretic peptide concentrations were elevated in patients with heart failure, and by univariate analysis were related to age, renal function, and other hormones. On multivariate analysis, tertile of plasma N-CNP interacted with tertile of plasma amino-terminal B-type natriuretic peptide to predict heart failure independent of age, gender, renal function, or echocardiographic left ventricular fractional shortening. N-CNP showed significant relations to concurrent plasma CNP, atrial natriuretic peptide (ANP), N-ANP, B-type (or brain) natriuretic peptide (BNP), N-BNP, endothelin-1, and adrenomedullin but not to echocardiographic indicators of left ventricular systolic function. Plasma amino-terminal C-type natriuretic peptide is elevated in heart failure and is related to other plasma hormones in heart failure. These findings suggest a possible compensatory response from the peripheral vasculature to heart failure by an endothelium-based vasodilator peptide and mandate further exploration of the role of C-type natriuretic peptide in this condition.

Adult↗

PubMed2003

Plasma amino-terminal pro-brain natriuretic peptide and accuracy of heart-failure diagnosis in primary care: a randomized, controlled trial.

OBJECTIVES: The purpose of this study was to determine the effect of amino-terminal pro-brain natriuretic peptide (N-BNP) on the diagnostic accuracy of heart failure (HF) in primary care. BACKGROUND: The accurate diagnosis of patients with suspected HF presenting in primary care is difficult. Amino-terminal pro-brain natriuretic peptide is present in high levels in cardiac dysfunction and may improve the diagnostic accuracy of HF in primary care. METHODS: The Natriuretic Peptides in the Community Study was a prospective, randomized controlled trial of the effect of N-BNP on the accuracy of HF diagnosis. Patients presenting to their general practitioner (GP) with symptoms of dyspnea and/or peripheral edema were included. The GPs formulated an initial diagnosis based on clinical assessment. All patients underwent a full cardiologic assessment that included echocardiography and N-BNP. Each patient was randomized to the BNP group (GP received the N-BNP result) or the control group (GP did not receive the N-BNP result). Patients were then reviewed by their GP, and their diagnosis was reviewed. The primary end point was the accuracy of the GPs' diagnoses compared with the panel standard. RESULTS: A total of 305 patients were included; mean age was 72 years, 65% were female. Seventy-seven patients met the panel criteria for HF. The diagnostic accuracy improved 21% in the BNP group and 8% in the control group (p = 0.002). The main impact of N-BNP measurement on diagnostic accuracy was the GPs' correctly ruling out HF. The number needed to diagnose by N-BNP measurement was seven patients. CONCLUSION: This study demonstrates that N-BNP measurement significantly improves the diagnostic accuracy of HF by GPs over and above customary clinical review.

Adult↗

PubMed2003

Effect of sub-elite competitive running on bone density, body composition and sexual maturity of adolescent females.

The attainment of optimal peak bone mass during adolescence is important in the primary prevention of osteoporosis. Exercise may contribute to skeletal development and bone density during growth, although competitive exercise is suggested to have an adverse effect. This study assesses the effect of moderate exercise on the bone density of adolescent females. Additionally, other factors which significantly influence attainment of peak bone mass were identified. This was a cross-sectional study of 42 adolescent females, classified as runners (n=15) or non-runners (n=27). Nutrient intake, energy expenditure, menstrual history and pubertal stage were recorded. Bone age, skinfold thickness, body composition and bone mineral density (BMD) of total body, lumbar spine and proximal femur were measured. Statistical analyses used Student's t-test, Pearson correlation and multiple regression analyses. Runners had lower fat mass and higher lean mass, with a trend to higher BMD in all sites measured. There were no significant differences in menstrual cycle regularity, age at menarche or number who had attained menarche. Pubic hair development was similar in both groups. Breast development was delayed in runners, although this may have been a function of lower fat mass in this group. When subjects were categorized according to menarchal status, postmenarchal girls were significantly taller and heavier, with higher fat mass and significantly higher total body and lumbar spine BMD. There was no significant relationship between BMD at any site and dietary nutrient intake. Multiple regression analyses, using BMD as the dependent variable, identified running status, pubertal stage, fat mass and lean mass as significant determinants. When BMD/height was used, significant determinants in total body BMD were fat mass, pubertal stage and running status, while in the lumbar spine, only the latter two variables remained significant. In conclusion, body composition, physical activity and sexual maturity were identified as significant determinants of bone density during adolescence. Runners had significantly lower body fat than non-runners, but this did not interfere with hormonal cyclicity, and caused no detriment to their bone density. The results of this study are reassuring, since they indicate that sub-elite competitive athletics has no detrimental effect on bone mass accrual in adolescent females.

Adolescent↗

PubMed2003

The effect of an integrated care approach for heart failure on general practice.

BACKGROUND: Recent studies have investigated specific strategies for heart failure management. None has involved collaboration between primary and secondary care. Potential gains for patients may result from collaborative strategies. OBJECTIVE: To assess the effect of an integrated management approach for patients with heart failure on general practice. METHODS: The study design was a cluster randomized controlled trial of integrated primary/ secondary care compared with usual care for heart failure patients. The study took place at Auckland Hospital, New Zealand and involved 197 patients admitted with an episode of heart failure. Patients were randomized to management group or control group (who received "usual" care). Management group patients received early clinical review, education sessions, a personal diary for medications and weight, and regular clinical follow-up alternating between GP and hospital clinic. Follow-up was for 12 months. RESULTS: Patients visited GPs frequently (median 14 visits, range 0-40), with no statistical difference between the two groups. Heart failure was the most common reason for consulting the GP. There was no relationship between GP consultations and patients' attendance at the study clinic, or hospital admissions. Management group GPs and patients expressed a high level of satisfaction. CONCLUSION: GP consultation rates were not affected by the programme. Further research will determine if general practice based programmes result in further gains.

Adult↗

PubMed2002

Pseudonormal mitral filling pattern predicts hospital re-admission in patients with congestive heart failure.

OBJECTIVES: We sought to investigate whether pseudonormal (PN) filling was associated with death or hospital admission in patients with congestive heart failure (CHF). BACKGROUND: The high mortality rate associated with CHF is related to many clinical and echocardiographic variables. In particular, a short mitral deceleration time and restrictive diastolic filling predict death and/or hospital admission. We hypothesized that differentiating patients with nonrestrictive filling might identify an intermediate PN group that may be associated with intermediate risk. METHODS: A total of 115 patients admitted to the hospital for exacerbation of CHF symptoms underwent pre-discharge Doppler echocardiography to determine mitral inflow (before and after preload reduction) and pulmonary venous return. Patients were followed up for one year, and all-cause mortality and re-admission data were analyzed. RESULTS: The classification of filling patterns was: abnormal relaxation (AR) in 46 (40%) patients, pseudonormal (PN) filling in 42 (36.5%) patients and restrictive filling pattern (RFP) in 27 (23.4%) patients. When comparing the RFP group with the AR group, all-cause mortality was higher (38.4% vs. 17.4%, p = 0.033), hospital admission was higher (70.3% vs. 54.3%, p = 0.073), death/hospital admission was higher (77.8% vs. 56.5%, p = 0.02), CHF hospital admission was higher (40.7% vs. 15.2%, p = 0.01) and death/CHF hospital admission was higher (62.9% vs. 26.1%, p = 0.0005). Mortality in the PN group was not significantly different from that in the two other groups, but re-admissions were higher than the AR group (76.2% vs. 54.3%, p = 0.006), as was death/re-admission (78.6% vs. 56.5%, p = 0.004) and death/CHF re-admission (47.6% vs. 26.1%, p = 0.03). Re-admissions in the PN and RFP groups were comparable. CONCLUSIONS: In a general hospital population of older patients with CHF, PN filling was associated with hospital admission rates similar to those seen with restrictive filling. The combined end point of death/CHF hospital admission was similar for restrictive filling and AR. Measurement of these variables is easy to add to routine clinical echocardiography and may provide important prognostic information in a wide range of patients with CHF.

Aged↗

PubMed2002

Accuracy of Orbscan II slit-scanning elevation topography.

PURPOSE: To establish the accuracy of Orbscan II (Orbtek Inc.) slit-scanning elevation topography in analyzing the anterior surface of complex test objects. SETTING: Discipline of Ophthalmology, University of Auckland, Faculty of Medical and Health Sciences, Auckland, New Zealand. METHODS: Six test objects were created from 2 materials: standard calibration poly(methyl methacrylate) (PMMA) (Orbtek Inc.) and a research PMMA material. The test objects were produced with spherical (radii of curvature 6.00 mm, 7.67 mm, and 8.88 mm), aspherical (apical radius 7.67, eccentricity 0.5, Q -0.25), and toroidal (7.67/7.92 mm radii of curvature) surfaces. The accuracy of the test surfaces was established by Form Talysurf Analysis. A single calibrated Orbscan II device was used to obtain 20 separate anterior elevation maps of each test object. The data obtained from Orbscan II, at 0.2 mm intervals along the chosen meridian, were directly compared with the Talysurf values for each test surface. RESULTS: Orbscan II measurements of all test objects were statistically significantly different from the Talysurf values (P <.001). The test objects produced from standard calibration material were more accurately measured by Orbscan II than the objects produced from the research material. Data obtained by Orbscan II from the central 3.5 mm of all test objects were more accurate than peripheral data when compared with the Talysurf values (P =.001). CONCLUSIONS: Orbscan II anterior surface elevation measurements differed significantly from Form Talysurf Analysis of complex test surfaces. However, the magnitude of the errors in the measurement of standard test objects was small, less than 0.20 microm centrally and 0.70 microm peripherally. Clinically, if similar accuracy of measurement is confirmed in the human eye, anterior surface elevation maps can be considered accurate representations of corneal shape.

Contact Lenses↗

PubMed2002

Personal computer-based PACS display system: comparison with a dedicated PACS workstation for review of computed radiographic images in rheumatoid arthritis.

RATIONALE AND OBJECTIVES: The authors' purpose was to investigate the reliability of a personal computer (PC)-based display system compared with a workstation in the evaluation of rheumatoid arthritis on computed radiographs of the hands. MATERIALS AND METHODS: Two radiologists on two occasions independently scored randomized computed radiographs of individual joints of the hands from 23 patients with rheumatoid arthritis and 14 control subjects. Each joint was scored from 0 (definitely normal) to 30 (severe disease) for each of four variables: soft-tissue swelling, osteopenia, erosions, and joint space narrowing. The observations were replicated on a picture archiving and communication system workstation and a PC. Intraobserver and interobserver reliability were calculated, as was the difference in scores between the two systems. The null hypothesis was that there was no difference between the workstation and the PC. RESULTS: The intraobserver reliability for normal versus abnormal joints was 73% with the workstation and 79% with the PC. The intraobserver reliability for workstation versus PC was 83%. There was moderate interreader reliability for both platforms (average kappa statistic, 0.46 [workstation] vs 0.45 [PC]). Small differences in scores between platforms are probably due mostly to the ordinal nature of the scoring system. CONCLUSION: For evaluating computed radiographs of the hands in early rheumatoid arthritis, a PC-based system provides results similar to those obtained with a workstation, at considerably reduced cost.

Arthritis, Rheumatoid↗