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Frequent and recurrent ventricular premature beats (VPB's) are considered to be associated with a higher risk of sudden cardiac death, particularly for survivors of myocardial infarction (MI). The distribution of VPB's has a large probability mass at zero, and a very heavy right hand tail. In this research, we fitted a model to VPB for patients for which VPB was present. The model was fitted on the basis of a relatively large data set on MI survivors in Israel. The model was fitted by a method which is based on the generalized linear model. This method, which was introduced by Zeger and Liang, is designed for longitudinal data and uses the quasi-likelihood concept. No specific assumptions are required on the shape of the distribution of the dependent variable. The results indicate that the model fits the data quite well but underestimates the very extreme high values. This research demonstrates the applicability of generalized linear models for longitudinal non-Gaussian data. Such data often arise in medical studies. The study also points out the distributional properties of VPB counts. In particular, it shows their associations with simple clinical and epidemiological variables, and with certain time periods during the day. 相似文献
3.
BACKGROUND: Normal spirometry is required for medical clearance of professional divers in many countries. Divers frequently have unusually large lung volumes associated with a low ratio of FEV(1) to FVC (FEV(1)%), suggestive of obstructive airways disease. We retrospectively analyzed the records of divers in the Israeli Navy with a low FEV(1)% who fulfilled the criteria for large lungs, to determine whether this might be the effect of training or natural selection. We also investigated changes in pulmonary function in relation to diving experience. METHODS: A total of 171 divers with FEV(1)% < 80% on simple spirometry were evaluated. We conducted a retrospective analysis of lung function data for those subjects who met the criteria for large lungs. RESULTS: One hundred nine of 171 divers with low FEV(1)% met the criteria for large lungs and were included in the study. Their average age was 25 years (range, 18 to 44 years), and their mean diving experience was 7 years (range, 0 to 26 years). No difference was found in FVC values between experienced and inexperienced divers. The mean forced expiratory flow at 50% of vital capacity was significantly reduced in the most experienced group compared with the novice or less experienced divers. No difference was found in the diffusing capacity of the lung for carbon monoxide between experienced and inexperienced divers. CONCLUSIONS: We suggest that large lungs may represent part of the natural selection for diving, rather than a training effect. Prolonged diving experience may result in the development of small airways disease. 相似文献
4.
Eder L Zisman D Barzilai M Laor A Rahat M Rozenbaum M Bitterman H Feld J Rimar D Rosner I 《The Journal of rheumatology》2008,35(5):877-882
OBJECTIVE: To investigate the prevalence of subclinical atherosclerosis among patients with psoriatic arthritis (PsA). METHODS: Forty patients with PsA were enrolled. Controls were matched by age, sex, and atherosclerotic risk factors. All patients and controls underwent duplex scan of the carotid arteries. Carotid intima-media thickness (IMT) was evaluated and the presence of atherosclerotic plaques was recorded. The plaques were graded and carotid plaque index was calculated. RESULTS: Patients with PsA had a higher IMT (mean +/- standard deviation, 1.04 +/- 0.35 mm vs 0.88 +/- 0.29 mm in controls; p = 0.03), and had a higher carotid plaque index than did matched controls (2.3 +/- 2.6, compared to 1.12 +/- 2.09; p = 0.03). Multivariate analysis demonstrated that PsA status as well as age and triglyceride levels were associated with the presence of carotid plaque. Other traditional risk factors were more prevalent among patients with PsA; however, they were not statistically significant. CONCLUSION: Our study demonstrates that patients with PsA may have an increased prevalence of subclinical atherosclerosis. These findings may not be solely attributable to traditional risk factors alone. Special attention and strict control of atherosclerotic risk factors in patients with PsA is warranted. 相似文献
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ABSTRACT: BACKGROUND: Numerous emerging data from research on osteoporosis among Asians found differences from Caucasians. Therefore, the aim of this study was to determine the prevalence of vitamin D insufficiency and osteoporosis in elderly participants from two nursing homes in Thailand, a country located near the equator. METHODS: The subjects of this cross-sectional study comprised 93 elderly Thai women who were living in institutional long-term nursing homes for the aged. Demographic data, daily food and calcium intake, physical activity, and sunlight exposure were measured. Lumbar spine and femoral neck bone mineral density (BMD) and biochemical levels including serum 25 hydroxyvitamin D [25(OH)D] and bone turnover markers were assessed. Vitamin D insufficiency was defined as 25(OH)D level < 70 nmol/l. RESULTS: The mean age of subjects was 75.2 +/- 6.0 (SD) years. Dietary calcium intake was low (322 +/- 158 mg/day) The mean 25(OH)D level was 64.3 +/- 14.9 nmol/L and the prevalence of vitamin D insufficiency was 38.7 % (95 % CI: 28.8 %, 49.4 %). There was no correlation between serum 25(OH)D concentrations and age (r = -.11, p = 0.3). The mean BMD of lumbar spine and femoral neck were 0.92 +/- 0.19 and 0.65 +/- 0.10 g/cm2, respectively. Nearly a half of the subjects had osteopenia (44.1 %, 95 % CI: 33.8 %, 54.8 %) and osteoporosis (47.3 %, 95 % CI: 36.9 %, 57.9 %). Circulating C-terminal telopeptide of type I collagen (CTx) level correlated significantly with both lumbar spine (r = -0.26, p = 0.01) and femoral neck BMD (r = -0.25, p = 0.02). CONCLUSIONS: More than one-third of Thai elderly women residing in nursing homes had vitamin D insufficiency. Almost all nursing home residents had osteoporosis and/or osteopenia. 相似文献
6.
Arnold C. Merrow Michael P. Reiter Andrew M. Zbojniewicz Tal Laor 《Pediatric radiology》2014,44(11):1436-1445
Although avulsion fractures of the pediatric knee are uncommon, they are important injuries to recognize because they are frequently associated with adjacent soft-tissue and osteocartilaginous abnormalities. Related injuries, which include entrapment of soft-tissue structures, intra-articular fracture extension, and intra-articular loose bodies, can complicate or alter therapy. The most commonly affected soft-tissue structures include the cruciate ligaments, collateral ligaments and supporting tendons, and extensor mechanism and retinacula. The purpose of this pictorial essay is to review avulsion fractures of the pediatric knee and to highlight associated injuries. 相似文献
7.
Avi Livneh Deborah Zemer Pnina Langevitz Arie Laor Ezra Sohar Mordechai Pras 《Arthritis \u0026amp; Rheumatology》1994,37(12):1804-1811
Objective. To elucidate factors possibly influencing the outcome of colchicine therapy in patients with amyloidosis of familial Mediterranean fever (FMF). Methods. Retrospective analysis of data abstracted from the charts of all 68 FMF patients with amyloidosis who presented during the study period (1974–1992) with proteinuria (≥0.5 gm/24 hours) and creatinine values ≤2.5 mg/dl, received colchicine, and were followed up for ≥5 years. Results. At the end of the study period, kidney disease had worsened in 31 patients and remained stable in 22. Proteinuria had regressed in 15 patients. Deterioration was related to initial serum creatinine values ≥1.5 mg/dl (P ≤ 0.01) and to mean colchicine dosage ≤1.5 mg/day (P ≤ 0.001). The 3 groups were comparable in terms of initial urinary protein levels, duration of proteinuria, presence of hypertension, occurrence of febrile attacks, sex distribution, and proportion of non-compliant patients. Conclusion. The therapeutic dosage of colchicine for amyloidosis of FMF is >1.5 mg/day. This dosage is effective only in patients with initial serum creatinine levels <1.5 mg/dl. 相似文献
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Minimizing radiation dose for pediatric body applications of single-detector helical CT: strategies at a large Children's Hospital 总被引:24,自引:0,他引:24
Donnelly LF Emery KH Brody AS Laor T Gylys-Morin VM Anton CG Thomas SR Frush DP 《AJR. American journal of roentgenology》2001,176(2):303-306
Adjustments of the standard helical CT protocols for adults can result in reduced radiation dose when imaging children. It is the radiologist's responsibility to critically evaluate the CT techniques used at their institution. Adjustments to CT protocols should be made to choose the appropriate mA and pitch when imaging children. 相似文献
10.
M. Vardi N. Petersil A. Keysary S. Rzotkiewicz A. Laor H. Bitterman 《European journal of clinical microbiology & infectious diseases》2011,30(12):1527-1530
Physicians often encounter patients who present with a vague clinical syndrome. A wide serological workup is often ordered, which may include tests for Coxiella burnetii in endemic areas. Often, the results of these tests pose new dilemma, with overlapping positive laboratory assays. The objective of this investigation was to characterise the serological overlap between acute Q fever and other infectious and immunological diseases. We retrospectively scanned the files of patients with a positive or equivocal immunoglobulin (Ig) M for C. burnetii phase II over a period of 8 years in a general hospital. Clinical and laboratory data, including antibodies to infectious agents and antibodies related to immunological states, were recorded. Anti-nuclear antibody (ANA), smooth muscle antibody (SMA) and rheumatoid factor were positive in 38%, 33.3% and 22.2% of the cases, respectively. In patients with acute Q fever, elevated IgM levels for Epstein–Barr Virus (EBV), cytomegalovirus (CMV), Mycoplasma pneumoniae, parvovirus, Bordetella pertussis, Rickettsia conorii and R. typhi were noted in 13.8%, 8.3%, 12.12%, 22.2%, 25%, 13% and 21.7% of cases, respectively. Acute Q fever induces a non-specific immunological arousal in a significant number of patients. This may interfere with diagnosis and delay treatment. Caution, clinical judgment and serological follow-up is warranted in such conditions. 相似文献