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Biomedical subjects

R Klein

Publications and source records attributed to R Klein.

At least 973 records · Page 54Linked to original sources
PubMedDate not supplied

The progression of retinopathy over 2 years: the Pittsburgh Epidemiology of Diabetes Complications (EDC) Study.

This study examined potential risk factors for the incidence and progression of retinopathy in a large representative cohort of childhood onset insulin-dependent diabetic patients. Participants in the Epidemiology of Diabetes Complications (EDC) Study underwent a full clinical examination at baseline and again at a 2-year follow-up. Retinopathy status was ascertained using stereo fundus photographs graded according to the modified Airlie House System. The study population is based on a large cohort of childhood-onset insulin-dependent diabetic patients, seen within 1 year of diagnosis at the Children's Hospital of Pittsburgh between January 1950 and May 1980. A total of 657 subjects participated at baseline (1986-1988), with 80% of eligible survivors taking part in the follow-up examination. This report concerns risk factors associated with the progression of diabetic retinopathy over a 2-year period, and the interaction of these factors with the presence of nephropathy. Analyses showed that baseline diastolic blood pressure was significantly associated with the incidence of any retinopathy, while glycosylated hemoglobin, baseline severity of retinopathy, serum triglycerides, and, to a lesser extent, higher levels of low-density lipoprotein (LDL) cholesterol and fibrinogen were associated with the progression of retinopathy. Progression to proliferative retinopathy was related to higher LDL cholesterol, fibrinogen, serum triglycerides, albumin excretion rate, and glycosylated hemoglobin (GHb). Risk factors varied with the presence of nephropathy. In the absence of nephropathy, GHb was a significant predictor of progression, whilst this was not the case in the presence of nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
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Retinal microvascular abnormalities and their relationship with hypertension, cardiovascular disease, and mortality.

Retinal microvascular abnormalities, such as generalized and focal arteriolar narrowing, arteriovenous nicking and retinopathy, reflect cumulative vascular damage from hypertension, aging, and other processes. Epidemiological studies indicate that these abnormalities can be observed in 2-15% of the nondiabetic general population and are strongly and consistently associated with elevated blood pressure. Generalized arteriolar narrowing and arteriovenous nicking also appear to be irreversible long-term markers of hypertension, related not only to current but past blood pressure levels as well. There are data supporting an association between retinal microvascular abnormalities and stroke, but there is no convincing evidence of an independent or direct association with atherosclerosis, ischemic heart disease, or cardiovascular mortality. New computer-related imaging methods are currently being developed to detect the presence and severity of retinal arteriolar narrowing and other microvascular characteristics. When reliably quantified, retinal microvascular abnormalities may be useful as risk indicators for cerebrovascular diseases.

Cardiovascular Diseases↗
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An international classification and grading system for age-related maculopathy and age-related macular degeneration. The International ARM Epidemiological Study Group.

A common detection and classification system is needed for epidemiologic studies of age-related maculopathy (ARM). Such a grading scheme for ARM is described in this paper. ARM is defined as a degenerative disorder in persons > or = 50 years of age characterized on grading of color fundus transparencies by the presence of the following abnormalities in the macular area: soft drusen > or = 63 microns, hyperpigmentation and/or hypopigmentation of the retinal pigment epithelium (RPE), RPE and associated neurosensory detachment, (peri)retinal hemorrhages, geographic atrophy of the RPE, or (peri)retinal fibrous scarring in the absence of other retinal (vascular) disorders. Visual acuity is not used to define the presence of ARM. Early ARM is defined as the presence of drusen and RPE pigmentary abnormalities described above; late ARM is similar to age-related macular degeneration (AMD) and includes dry AMD (geographic atrophy of the RPE in the absence of neovascular AMD) or neovascular AMD (RPE detachment, hemorrhages, and/or scars as described above). Methods to take and grade fundus transparencies are described.

Aged↗
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Heterogeneous regional expression patterns of matrix metalloproteinases in human malignant gliomas.

The aim of the study was to assess the differential intra- and intertumoral heterogeneity and patterns of matrix metalloproteinase expression in human glioblastomas in vivo. 12 glioblastoma samples were analyzed for MMP expression by semi-quantitative RT-PCR. A total of 56 samples (8 adjoining regions of 6 glioblastoma tumors) were immunohistochemically examined for the expression and regional distribution of gelatinase-A (MMP-2), gelatinase-B (MMP-9), matrilysin (MMP-7) and stromelysin-1 (MMP-3). Gelatinase-A mRNA was detected in all samples, gelatinase-B was found in numerous samples. Correspondingly, strong expression levels of both gelatinase protein was seen in immunohistochemistry. Gelatinase-A was expressed by both tumor cells and endothelium while gelatinase-B was found to be restricted to endothelial cells. Stromelysin-1 protein was not detected in any of the samples. Matrilysin was found around tumor cells of three samples from one patient only. The strong immunoreactivity seen for gelatinase-A around tumor cells and blood vessels suggests a role in both tissue degradation and tumor neoangiogenesis which is in accordance with previously published in vitro data. The marked localization of gelatinase-B to the endothelium and its presence in non-infiltrative benign lesions, however, makes a direct proteolytic role of gelatinase-B on ECM components during glioma invasion appear unlikely. Its close association with vascular structures, however, might indicate a link to neoangiogenesis. The significance of matrilysin which was only seen in tumor cells in three samples remains unclear. Stromelysin-1, though strongly expressed in cell lines, does not appear to play a role in glioblastoma tumors in vivo.

Brain Neoplasms↗
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Does the severity of diabetic retinopathy predict pregnancy outcome?

The authors sought to determine whether the severity of diabetic retinopathy is a predictor of subsequent pregnancy outcome. One hundred and seventy-nine pregnant diabetic women were evaluated in their first trimester of pregnancy. Stereoscopic color photographs of the ocular fundus were taken and graded by the Fundus Photography Reading Center. Thirty-nine women had no retinopathy, while 28 had proliferative retinopathy in the worse eye. The women's history and hospital delivery room charts were reviewed with regard to pregnancy outcome. Thirty-three pregnancies terminated with an adverse outcome. A logistic regression analysis was used to evaluate significant predictors of pregnancy outcome. Of maternal age, duration of diabetes, glycosylated hemoglobin, proteinuria, cigarette smoking status, and severity of diabetic retinopathy, only the last variable significantly predicted an adverse outcome. These data suggest that the severity of retinopathy should be considered when counseling a pregnant diabetic woman.

Adolescent↗
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Production of Co-60 sources for high-accuracy efficiency calibrations of gamma-ray spectrometers.

Activity determination by gamma-ray spectrometry is a valuable aid which is widely used where radioactive sources are applied. For the construction of an efficiency curve vs. energy in a standard geometry, the accuracy is limited not only by the uncertainty of peak area determination and the knowledge of the relevant emission probabilities but also by the uncertainties of the activity values applied to efficiency calibration with standard sources. Recently, a method to determine a relative efficiency function using selected radionuclides with gamma cascades of well known emission probabilities has been developed which yields very accurate efficiency values. Such a curve has to be converted into an absolute efficiency curve by calibration of the detector system with at least one source of very well known activity. Especially for this purpose, a set of Co-60 gamma-ray spectrometer sources was produced at the PTB. The activity values (10-45 kBq) were measured by the 4pi beta-gamma coincidence technique with a standard uncertainty of less than 0.1%. Production and measurement of these sources are described in the present paper. Special care was taken to include all contributions to the standard uncertainty of the activity value when establishing the uncertainty budget for the activity of each of these sources. The activity ratio of two of these sources, as obtained by the absolute measurements, was checked by independent gamma-ray counting at two other laboratories, where the precision achieved was less than 0.2%. The procedure described is considered to be a step towards more accurately determined efficiency functions in gamma-ray spectrometry.

Journal Article↗
PubMedDate not supplied

Is peak expiratory flow rate a predictor of complications in diabetes? The Wisconsin Epidemiologic Study of Diabetic Retinopathy.

The Objective of this study was to determine whether peak expiratory flow rate is a predictor of complications of diabetes. Peak expiratory flow rate was measured at the 10-year follow-up (third examination) of a cohort of persons with younger-onset diabetes. The relationships of progression of diabetic retinopathy by two steps, progression to proliferative retinopathy and of incidences of macular edema, sore or ulcers on feet or ankles, lower extremity amputation, proteinuria, and cardiovascular disease 4 years after this examination with respect to peak expiratory flow rate were evaluated. Study procedures including measurements of blood pressure, height and weight, grading of fundus photographs, peak expiratory flow rate, urinalysis, and medical history were performed according to standard protocols. Peak expiratory flow rate was not associated in univariate analyses with progression of retinopathy, incidences of proliferative retinopathy, macular edema or lower extremity amputation, sores or ulcers on feet or ankles, gross proteinuria, or self-reported cardiovascular disease. However, when using multivariable models to include the effects of other risk factors, peak expiratory flow rate was significantly associated with the combined incidences of sores or ulcers on feet and ankles, or lower extremity amputations (OR=0.61, 95% CI 0.42-0.88). These data suggest that peak expiratory flow rate is a predictor of subsequent complications in the lower extremities in those with long duration of younger-onset diabetes. Evaluating this association in an incipient cohort would illuminate whether the relationship we found is likely to be causal.

Adult↗
PubMedDate not supplied

[Why do newborn infants already suffer from "stroke". Studies of focal, arterial, ischemic infarct].

In most cases the etiology of the focal ischemic stroke in newborns is still obscure. We considered patients with congenital hemiparesis due to a lesion in the territory of the middle cerebral artery (shown by CT or MRI) as a model of this infarction. A detailed history including maternal and familiar data was obtained from 9 affected patients. Duplex-sonography was performed and biochemical parameters were analysed in all patients and their mothers. There were no convincing hints for a prenatal (for instance infectious, traumatic or toxic) origin. Also the reconstruction of the perinatal period could not explain the infarction. Duplex-sonography revealed no anatomic variants of the intra- or extracerebral arteries. Haemostasiological results were within normal limits--except the antiphospholipid antibodies, which were detected in 7 of the 9 families (patient or mother). The significance of these results is still unknown. We propose, antiphospholipid antibodies and further haemostasiological parameters should be investigated as near as possible to the neonatal period.

Adolescent↗
PubMedDate not supplied

Women as body parts in the era of reproductive and genetic engineering.

Reproductive and genetic engineering are presented by their promoters as miracle cures for people with infertility problems or who are at genetic risk in having their desired healthy child. Focusing on the test-tube baby method (in vitro fertilization), in this article I investigate the medical reality of these technologies and their impact on women's lives as individuals and as members of a social group, women. Specifically, I discuss these developments in a global context and suggest that, in connection with fertility-control methods, they could be used as the ultimate means of population control. I contend that reproductive and genetic engineering dismember, fragment, and dissect women into their body parts and that, in the interests of women with a right to bodily integrity and dignity, they need to be stopped.

Female↗
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Improving excellence in scoliosis rehabilitation: a controlled study of matched pairs.

OBJECTIVES: Physiotherapy programmes so far mainly address the lateral deformity of scoliosis, a few aim at the correction of rotation and only very few address the sagittal profile. Meanwhile, there is evidence that correction forces applied in the sagittal plane are also able to correct the scoliotic deformity in the coronal and frontal planes. So it should be possible to improve excellence in scoliosis rehabilitation by the implementation of exercises to correct the sagittal deformity in scoliosis patients. An exercise programme (physio-logic exercises) aiming at a physiologic sagittal profile was developed to add to the programme applied at the centre or to replace certain exercises or exercising positions. MATERIAL AND METHODS: To test the hypothesis that physio-logic exercises improve the outcome of Scoliosis Intensive Rehabilitation (SIR), the following study design was chosen: Prospective controlled trial of pairs of patients with idiopathic scoliosis matched by sex, age, Cobb angle and curve pattern. There were 18 patients in the treatment group (SIR + physio-logic exercises) and 18 patients in the control group (SIR only), all in matched pairs. Average Cobb angle in the treatment group was 34.5 degrees (SD 7.8) Cobb angle in the control group was 31.6 degrees (SD 5.8). Age in the treatment group was at average 15.3 years (SD 1.1) and in the control group 14.7 years (SD 1.3). Thirteen of the 18 patients in either group had a brace. Outcome parameter: average lateral deviation (mm), average surface rotation ( degrees ) and maximum Kyphosis angle ( degrees ) as evaluated with the help of surface topography (Formetric-system). RESULTS: Lateral deviation (mm) decreased significantly after the performance of the physio-logic programme and highly significantly in the physio-logic ADL posture; however, it was not significant after completion of the whole rehabilitation programme (2.3 vs 0.3 mm in the controls). Surface rotation improved at average 1.2 degrees in the treatment group and 0.8 degrees in the controls while Kyphosis angle did not improve in both groups. DISCUSSION: The physio-logic programme has to be regarded as a useful 'add on' to Scoliosis Rehabilitation with regards to the lateral deviation of the scoliotic trunk. A longitudinal controlled study is necessary to evaluate the long-term effect of the the physio-logic programme also with the help of X-rays.

Adolescent↗
PubMedDate not supplied

Diphtheria and hearing loss.

OBJECTIVE: To determine if infectious diseases usually experienced in childhood have an effect on hearing ability later in life. METHODS: The Epidemiology of Hearing Loss Study (N = 3,753) is a population-based study of age-related hearing loss in adults aged 48 to 92 years in Beaver Dam, Wisconsin. As part of this study, infectious disease history was obtained and hearing was tested using pure-tone audiometry. Hearing loss was defined as a pure-tone average of thresholds at 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz greater than 25 decibels hearing level in either ear. RESULTS: After adjusting for confounders, only a history of diphtheria (n = 37) was associated with hearing loss (odds ratio [OR] 2.79; 95% confidence interval [CI] 1.05, 7.36). There was no relationship between hearing loss and history of chickenpox, measles, mumps, pertussis, polio, rheumatic fever, rubella, or scarlet fever. Only two participants with a history of diphtheria and hearing loss reported having a hearing loss before age 20. CONCLUSIONS: Diphtheria in childhood may have consequences for hearing that do not become apparent until later in life. A possible biological mechanism for a diphtheria effect on hearing ability exists: The toxin produced by the Corynebacterium diphtheriae bacteria can cause damage to cranial nerves and therefore may affect the auditory neural pathway. These data may have important implications for areas facing a resurgence of diphtheria cases.

Adult↗
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Can the clearance of tumor necrosis factor alpha and interleukin 6 be enhanced using an albumin dialysate hemodiafiltration system?

Patients with acute hepatic failure (AHF) have elevated levels of inflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6). Recently, we have shown selective hemodiafiltration with albumin dialysis, as an extracorporeal liver support device (ECLVS), to be effective in the clearance of multiple toxins that are elevated in AHF. Our objective was to evaluate whether ECLVS would be effective in the clearance of TNF-alpha and IL-6. An in vitro continuous hemodiafiltration circuit was used with single pass counter-current dialysis. A known amount of recombinant rat TNF-alpha and IL-6 was added to heparinized bovine blood and filtered across a polyalkyl sulfone hemofilter using matched filtration and dialysate flow rates. During 4 hours, the serial TNF-alpha and IL-6 concentrations were measured in the circulating blood, and the content of each cytokine was calculated using mass balance. For each cytokine, clearance was determined for two dialysate groups at constant temperature and pH (group 1: dialysate = 0.9 normal saline, n = 5; group 2: dialysate = albumin 2 gm/dl, n = 5). Analysis of data was performed using ANOVA and Student's t-test. There was improved clearance of TNF-alpha and IL-6 when albumin was used in the dialysate (81+/-0.09% of the initial TNF-alpha and 77+/-0.04% of the IL-6 quantities) compared with when 0.9 normal saline was used as the dialysate (58+/-0.14% of the initial TNF-alpha and 56+/-0.18% of the IL-6 quantities); p < 0.03. An ECLVS utilizing hemodiafiltration with albumin dialysis is more effective than conventional hemofiltration in the clearance of TNF-alpha and IL-6 and, therefore, may benefit patients with acute hepatic failure.

Albumins↗
PubMedDate not supplied

Clinical nursing experience with cultured epidermal autografts.

In 1989, the Regional Burn Center of the Children's Hospital Medical Center of Akron, Ohio, switched to use of commercially produced cultured epidermal autograft (CEA) from cultured cells that had been grown in the institution's own laboratories. CEA has the advantage of producing the quantity of grafts that are needed from the original biopsy specimen. Clinical experience with 10 patients has demonstrated an average of 72% "take" with approximately 1309 grafts. Arms, legs, and anterior trunk are the preferred sites for coverage. Patient/family education is an integral component of the CEA regimen; a structured educational program begins immediately. The cooperation of both patient and family is often a critical factor in successful grafting. Usually one to two biopsy specimens from the groin or the axilla are sent for culturing. The patient receives standard burn care while cultured tissue is grown, which includes physical therapy and splinting. Early excision, temporary coverage with cadaver skin, topical antibiotics, graft protection, and pain control are keys to success. Physical therapy and splinting are delayed until after removal of the graft backing, which usually occurs 10 to 12 days after CEA is applied.

Burn Units↗
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Brain and atrial natriuretic peptides in patients with ischemic heart disease with and without heart failure.

The objective of the study was the evaluation of natriuretic peptides in ischemic heart disease. Atrial and brain peptides (ANP, BNP) were elevated in patients with ischemic heart failure, as compared with patients with angina without over failure, and controls (p < 0.01). BNP/ANP ratio was higher in NYHA class IV than in class III patients (2.67 +/- 0.87 vs. 1.52 +/- 0.59, respectively). Patients in the angina group, in whom elevated BNP or ANP was found, had subclinical systolic or diastolic dysfunction. There was inverse correlation between BNP, ANP and the left-ventricular ejection fraction (each r = 0.78, p < 0.001). We conclude that BNP is elevated as a result of myocardial dysfunction, but not of ischemia and seems to be a better index of disease stage and prognosis than ANP.

Adult↗
PubMedDate not supplied

The Beaver Dam Health Outcomes Study: initial catalog of health-state quality factors.

The Beaver Dam Health Outcomes Study (BDHOS) is an ongoing longitudinal cohort study of health status and health-related quality of life for a random sample of adults (age range at interview was 45 to 89 years; mean = 64.1, SD = 10.8) in a community population. In a face-to-face interview lasting approximately an hour, each participant responds to several batteries of questions. Included are a history of chronic medical conditions, current medications, and past surgeries; the SF-36 (a general health-status questionnaire); the Quality of Well-being index; self-rated health status on a five-point scale from "excellent" to "poor"; and evaluation of current health using the method of time tradeoffs. The authors present results from 1,356 interviews on these four principal measures, reporting mean scores by sex, by age, and for persons reporting being affected by various medical conditions. They believe data from the BDHOS will provide researchers and policy makers a reference collection of vital statistics for health-related quality of life. Additionally, the data provide a way to compare results from studies that utilize different indices from among the four principal measures of the BDHOS.

Adult↗
PubMedDate not supplied

Predicting Quality of Well-being scores from the SF-36: results from the Beaver Dam Health Outcomes Study.

BACKGROUND: The SF-36 and the Quality of Well-being index (QWB) both quantify health status, yet have very different methodologic etiologies. The authors sought to develop an empirical equation allowing prediction of the QWB from the SF-36. DATA: They used empirical observations of SF-36 profiles and QWB scores collected in interviews of 1,430 persons during the Beaver Dam Health Outcomes Study, a community-based population study of health status, and 57 persons from a renal dialysis clinic. METHOD: The eight scales of the SF-36, their squares, and all pairwise cross-products, were used as candidate variables in stepwise and best-subsets regressions to predict QWB scores using 1,356 interviews reported in a previous paper. The resulting equation was cross-validated on the remaining 74 cases and using the renal dialysis patients. RESULTS: A six-variable regression equation drawing on five of the SF-36 components predicted 56.9% of the observed QWB variance. The equation achieved an R2 of 49.5% on cross-validation using Beaver Dam participants and an R2 of 58.7% with the renal dialysis patients. An approximation for computing confidence intervals for predicted QWB mean scores is given. CONCLUSION: SF-36 data may be used to predict mean QWB scores for groups of patients, and thus may be useful to modelers who are secondary users of health status profile data. The equation may also be used to provide an overall health utility summary score to represent SF-36 profile data so long as the profiles are not severely limited by floor or ceiling effects of the SF-36 scales. The results of this study provide a quantitative link between two important measures of health status.

Activities of Daily Living↗