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Biomedical subjects

M Blum

Publications and source records attributed to M Blum.

At least 19 recordsLinked to original sources
PubMed2006

[The myogenic response of retinal arterioles in diabetic retinopathy].

OBJECTIVES: The retinal vessel analyzer (RVA) offers the unique opportunity for noninvasive online measurements of the "Bayliss effect." In the presented study this myogenic response is used to test vessel contractility of retinal arterioles in different stages of diabetic retinopathy (DR). METHODS: Forty patients with diabetes were exposed to a standardized rise in blood pressure. The myogenic response of a retinal arteriole was measured by continuous use of the RVA during this time. The subjects were divided into four groups (each n=10) according to different stages of DR. Group I: no DR, group II: mild/moderate DR, group III: moderate/severe nonproliferative DR with laser treatment, and group IV: proliferative DR with laser treatment. RESULTS: A similar blood pressure rise was achieved in all subjects. In response to this BP rise, group I demonstrated a vasoconstriction of -7.6% (+/-4.1). In group II -0.85% (+/-4.3) and in group III a mild vasodilation of +0.44% (+/-5.9) was found. Group IV presented a vasodilatation of +3.2% (+/-5.9). CONCLUSION: According to the progression of the morphological changes in diabetic retinopathy a functional deficit in the autoregulation of retinal arterioles can be measured with the RVA.

Blood Pressure↗
PubMed2006

[Presbyopia treatment using a femtosecond laser].

Presbyopia is by far the most common refractive error worldwide, with no permanent therapeutic option available. All efforts to restore accommodation by the use of surgery have not led to a generally accepted therapy. However, there is evidence from an animal model that the use of a femtosecond (fs) laser might influence the modulus of elasticity in the lens. Fs-laser impulses can create intralenticular disruption in animal eyes as well as human cadaver lenses and improve elasticity. The concept of treating presbyopia with fs-laser requires a new, complex theory combining the optical and the mechanical aspects of accommodation in the eye. Diagnostic tools for measuring optical change in power and geometrical modification as the eye views from far to near are needed to obtain objective clinical data. A non-invasive treatment of presbyopia to restore accommodation might be possible in the future.

Accommodation, Ocular↗
PubMed2006

[Selenium and cataract--risk factor or useful dietary supplement?].

BACKGROUND: The exact role of selenium in cataract development is still unclear. Both protective and toxic effects and mechanisms have been postulated in the past. Accordingly, the selenium contents in human lenses and blood sera in different forms of cataract were investigated. METHODS: 123 patients (76 female and 37 male) with a mean age of 69.8 years (range: 17 to 91 years) were enrolled in this study. Overall, 84 lenses (after ECCE) and 110 blood serum samples were investigated by atomic absorption spectroscopy. Interpretation of data was accompanied by exact preoperative investigations including Scheimpflug techniques. RESULTS: A significant increase of selenium content of the lenses was found with increasing lens opacification and colouration. Lenses with a mature cataract showed the highest selenium contents in the lens compared to other cataract forms. Opposite results were detected in blood serum. Lenses of diabetics showed already at a younger age changes in selenium content. Smokers showed both decreased selenium contents in the lens and decreased selenium concentration in blood serum. CONCLUSIONS: An obvious correlation between the type of cataract and selenium content of the lens seems to exist. The question by which mechanism selenium acts directly or by selenium-dependent enzymes acts lens opacification remains speculative up to now.

Adolescent↗
PubMed2005

[Percutaneous liver biopsy. Overview of different techniques].

To classify a liver tumor, image-guided percutaneous biopsy of a liver lesion is indicated. Using ultrasound (US) to guide a biopsy needle into a liver lesion has been proven useful and safe. If a lesion cannot be seen on US or the access to a lesion has been complicated by its position, CT-guided biopsy can be performed. If a lesion cannot be delineated on US or CT, MR-guided biopsy is recommended. Using hepatospecific contrast agents, the time span to delineate tumor tissue can be prolonged. To differentiate diffuse liver disease, transvenous biopsy under fluoroscopic control can be performed if a percutaneous biopsy is contraindicated. In recent years fine-needle aspiration biopsy has been increasingly replaced by coaxial 14-20 G core biopsy, which is a safe and efficient technique to classify liver lesions and has a low complication rate.

Biopsy, Fine-Needle↗
PubMed2005

[Contractility of human retinal arterioles during oxygen breathing vs. myogenic response].

BACKGROUND: By the use of the retinal vessel analyzer (RVA) it is possible to measure the myogenic response of retinal arterioles to blood pressure increases. Pure oxygen breathing is another method to test the contractility of vessels. The presented study compares these two methods in the same healthy volunteers. METHODS: After a 3-minute baseline measurement 20 healthy volunteers (age: 22 - 58 years) were exposed to 100 % oxygen breathing for 5 minutes. The diameter of an retinal arteriole was measured continuously during that period of time. The very same persons were tested in a 9-minute experiment with isometric exercise to cause a vasoconstriction by an increase in mean arterial blood pressure (MAP). RESULTS: Oxygen breathing resulted in a vasoconstriction of - 7.45 (+/- 2.1) % on average. The same individuals reacted with an MAP rise of 24.0 (+/- 5.9) mm Hg to isometric exercise, answered by a vasoconstriction of - 5.3 (+/- 2.1) %. Both tests were significantly correlated to each other. CONCLUSIONS: Although the two tests trigger different autoregulative responses in the arteriole vasoconstriction due to MAP increases and vasoconstriction as an answer to 100 % oxygen breathing they do correlate at a significant level in the same subjects.

Adult↗
PubMed2005

[Haemodynamics and diabetic retinopathy].

Diabetic retinopathy is the most common cause of blindness in adults in all industrialised countries. A much better pathophysiological understanding of the disease has been achieved during the last years. There is evidence that a functional deficit in haemodynamics proceeds the morphological changes of the retina. Modern technologies for measuring haemodynamic parameters and their correlation to pathophysiology in diabetic retinopathy are discussed. In the near future it will be possible to use these parameters as an early sign of worsening before morphological changes occur. Measurement of the therapeutic success, e. g., in laser coagulation would seem to be possible.

Blood Flow Velocity↗
PubMed2004

[Percutaneous radiofrequency ablation of liver cell carcinoma: a current overview].

In patients with hepatocellular carcinoma (HCC) surgical resection so far offers potential cure. Due to the frequent association with liver cirrhosis less then 30% of patients with HCC can be resected. In unresectable cases, radiofrequency ablation (RFA) offers an effective treatment alternative. Substantial improvements in the development of powerful generators (up to 250 W) combined with expandable, closed or open-perfused needle electrodes, provide coagulation necroses up to 5 cm in diameter. Most recently primary technical success rates of 85 to 100% were reported. Following RFA of HCC's (diameter up to 2,8 cm) 1-, 2-, 3 and 5-year survival was reported to be 97, 89, 71 and 48%. Low complication rates of 0-12% and a mortality of 0-1% indicate the minimal-invasive character of RFA. Basic principles, technique, indications, contraindications and limitations of percutaneous RFA will be discussed together with a presentation of own cases and a review of literature.

Carcinoma, Hepatocellular↗
PubMed2004

Correction of anemia in patients with congestive heart failure increases resting energy expenditure.

BACKGROUND & AIM: Congestive heart failure (CHF) and anemia were reported to affect resting energy expenditure (REE). The aim of this study was to evaluate the effect of the correction of anemia on REE in subjects with CHF. PATIENTS AND METHODS: Nine anemic patients with compensated CHF and CRF were studied before and after correction of anemia. REE was studied by an open circuit indirect calorimeter, body composition by dual-energy-X-ray absorption and total body and extracellular water by multi-frequency bioelectrical impedence. Four anemic and 5 non-anemic CHF patients who did not receive any new treatment served as controls. RESULTS: After the correction of their anemia patients tended to increase weight (P<0.06), but no significant changes were observed in body composition. Daily caloric intake increased significantly (P<0.02). Ejection fraction increased (P<0.05) and pulse rate decreased significantly (P<0.001). REE and REEPP were in the normal range before correction but increased significantly afterwards (1402+/-256 vs. 1496+/-206 kcal/d, and 101+/-9 vs. 109+/-8, P<0.023 and P<0.006, respectively). CONCLUSION: Correction of anemia in patients with CHF increases their REE. This can be related either to improved tissue oxygenation and/or to increased caloric intake.

Aged↗
PubMed2003

Leptin, body composition and bone mineral density in premenopausal women.

Body weight is known to be associated with bone mass, however, it is unclear whether body composition, as reflected by the percent of total weight that is fat tissue (%fat), is associated with bone mass independently of weight. Fat tissue is metabolically active, and hormonal factors may mediate an association of %fat with bone mass. Leptin, a hormone produced in fat tissue, has recently been shown to be inversely related to bone mass in mice, but whether it is related to human bone mass is uncertain. We sought to investigate the associations of %fat and of serum leptin concentration with bone mineral density (BMD) in a cohort of 153 premenopausal women. BMD measurements of the total hip, lumbar spine and total body as well as body composition were measured by dual energy X-ray absorptiometry (DXA). Serum leptin levels were established using a commercial competitive binding assay. Individually, body weight, %fat and leptin were each positively associated with BMD at all three sites. However, when we examined BMD either as a function of both body weight and %fat together, or as a function of both body weight and leptin together, we found that for a given body weight, BMD appeared to be inversely associated with %fat and similarly appeared to be inversely associated with leptin. When BMD was examined as a function of %fat and leptin together, we found that for a given %fat, leptin appeared to be inversely associated with BMD. In summary, the results of this study suggest that for a given body weight, a higher proportion of fat and a higher serum leptin concentration have negative associations with bone mass in premenopausal women.

Absorptiometry, Photon↗
PubMed2003

[Vasoconstriction of retinal arterioles with oxygen breathing in diabetic retinopathy].

OBJECTIVES: The retinal vessel analyzer (RVA) offers the unique opportunity of noninvasive online measurements of retinal vessel diameters. Breathing 100% oxygen is used to test vessel contractility of retinal arterioles in different stages of diabetic retinopathy (DR). METHODS: After a 3-min baseline measurement 40 patients with diabetes were exposed to 100% oxygen breathing for a 5-min period. The diameter of a retinal arteriole was measured with the RVA continuously during this time. Subjects were divided into four groups according to different stages of DR. Group I: no RD; group II: mild/moderate RD; group III: moderate/severe nonproliferative RD with laser treatment; group IV: proliferative RD with laser treatment. RESULTS: Group I (n=12) demonstrated a vasoconstriction of 6.2% (+/-4.0). In group II (n=8) 6.1% (+/-2.8) and in group III (n=8) 6.6% (+/-4.1) vasoconstriction was found. Group IV (n=12) presented a vasodilatation of +2.5% (+/-4,7). CONCLUSION: No significant differences could be found in the vasoreaction to 100% oxygen breathing in different stages of nonproliferative RD. However, a significant reduction could be demonstrated in proliferative DR with this method.

Administration, Inhalation↗
PubMed2003

The cardio renal anemia syndrome: correcting anemia in patients with resistant congestive heart failure can improve both cardiac and renal function and reduce hospitalizations.

Anemia (Hemoglobin of < 12 to 13 g/dl) is frequently encountered in patients with congestive heart failure (CHF). This anemia may be partly due to hemodilution, partly to the associated reduction in renal function, and partly to the use of ACE inhibitors and aspirin. However, there is evidence that CHF alone--through excessive cytokine production may also reduce the bone marrow and cause anemia. In several recent studies anemia has been found to be associated with a more severe degree of CHF, a higher rate of death, renal failure, hospitalization and evidence of malnutrition. In both uncontrolled and controlled studies correction of anemia with erythropoietin with or without the addition of i.v. iron has been attempted. The correction of anemia has been associated with a marked improvement in New York Heart Association (NYHA) functional cardiac class and Left Ventricular Ejection Fraction, a marked reduction in the need for hospitalization and high dose oral and i.v. diuretics, and an improvement in exercise capacity, peak exercise oxygen utilization and quality of life. The serum creatinine, which had been increasing steadily before treatment, stabilized with the correction of anemia. All this suggests that control of anemia in CHF could become a valuable addition to the therapeutic armamentarium of CHF and might also play a major role in the prevention of progressive renal failure.

Anemia↗
PubMed2002

Recall of early menstrual history and menarcheal body size: after 30 years, how well do women remember?

The validity of recall of early menstrual characteristics is of interest because of their putative role in the etiology of breast cancer and other diseases. A retrospective follow-up of the Newton Girls Study (1965-1975) provided an opportunity to assess the accuracy and precision of recall of several early menstrual characteristics. In 1998-1999, 57 percent of the original 793 Newton Girls Study participants completed a mailed questionnaire to assess the accuracy of recall for age and body size at menarche, usual cycle length during the first 2 years, and age at regularity. Recalled and original age at menarche were highly correlated (r = 0.79, p < 0.001). The body mass index percentile at menarche was well correlated with recalled body size at menarche (r = 0.61, p < 0.001), but with some evidence of systematic bias. Overall, a woman's recall of menarcheal age and body size was better than recall of cycle length and occurrence of regularity. The failure to identify certain menstrual characteristics as exposures for subsequent disease may reflect limitations in the accuracy and precision of the recalled measures.

Adult↗
PubMed2002

Household tobacco smoke exposure is negatively associated with premenopausal bone mass.

Subjects exposed to environmental tobacco smoke have been found to be at increased risk for several health problems. Whether exposure to passive tobacco smoke is associated with reduced bone mineral density (BMD) is unknown. In order to examine this, we measured BMD in 154 healthy premenopausal women (age range 40-45 years). BMD of the total hip, femoral neck, lumbar spine and total body was measured by dual-energy X-ray absorptiometry (DXA). Data were collected on exposure to household tobacco smoke from age 10 years to the present as well as on other lifestyle factors related to bone mass. We found that 67.5% of the subjects had a history of household tobacco smoke exposure. Subjects exposed to household tobacco smoke had a mean adjusted BMD that was significantly lower at the total hip ( p = 0.021) and femoral neck ( p = 0.018) compared with subjects who were not exposed. In addition, duration of household tobacco smoke exposure was negatively associated with BMD at the total hip ( p = 0.010), femoral neck ( p = 0.004), lumbar spine ( p = 0.037) and total body ( p = 0.031). Subjects exposed to household tobacco smoke for 15 years or more had mean adjusted BMD that was 4% lower at the total body, and more than 8% lower at the total hip, femoral neck and lumbar spine, compared with subjects who were not exposed. In conclusion, household tobacco smoke exposure during adolescence and young adulthood was found to be negatively associated with BMD at the total hip and femoral neck, and duration of exposure was negatively associated with BMD at the total hip, femoral neck, lumbar spine and total body in premenopausal women.

Absorptiometry, Photon↗
PubMed2002

Embryonic lethality caused by apoptosis during gastrulation in mice lacking the gene of the ADP-ribosylation factor-related protein 1.

ADP-ribosylation factor (ARF)-related protein 1 (ARFRP1) is a membrane-associated GTPase with significant similarity to the family of ARFs. We have recently shown that ARFRP1 interacts with the Sec7 domain of the ARF-specific guanine nucleotide exchange factor Sec7-1/cytohesin and inhibits the ARF/Sec7-dependent activation of phospholipase D in a GTP-dependent manner. In order to further analyze the function of ARFRP1, we cloned the mouse Arfrp1 gene and generated Arfrp1 null-mutant mice by gene targeting in embryonic stem cells. Heterozygous Arfrp1 mutants developed normally, whereas homozygosity for the mutant allele led to embryonic lethality. Cultured homozygous Arfrp1 null-mutant blastocysts were indistinguishable from wild-type blastocysts. In vivo, they implanted and formed egg cylinder stage embryos that appeared normal until day 5. Between embryonic days 6 and 7, however, apoptotic cell death of epiblast cells occurred in the embryonic ectoderm during gastrulation, as was shown by histological analysis combined with terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling. Epiblast cells that would normally differentiate to mesodermal cells detached from the ectodermal cell layer and were dispersed into the proamniotic cavity. In contrast, the development of extraembryonic structures appeared unaffected. Our results demonstrate that ARFRP1 is necessary for early embryonic development during gastrulation.

ADP-Ribosylation Factors↗
PubMed2002

Increased content of zinc and iron in human cataractous lenses.

The purpose of the study was to examine the zinc and iron content of human lenses in different types of cataract and to investigate the possible influence of diabetes on the zinc and iron content of the lens. Iron and zinc of 57 human lenses (28 corticonuclear cataracts and 29 mature cataracts with a mean age of 70.6 +/- 16.1 and 74.7 +/- 11.1 yr, 41 nondiabetics and 16 diabetics) were determined by atomic absorption spectroscopy. The zinc content of human lenses was significantly increased in mature cataracts compared to corticonuclear cataracts (0.51 +/- 0.33 vs 0.32 +/- 0.20 micromol/g dry mass, p=0.012). The iron content of mature cataracts was also higher than in corticonuclear cataracts (0.11 +/- 0.09 vs 0.07 +/- 0.05 micromol/g dry mass, p=0.071). Furthermore, a significant increase of the lens zinc content could be observed with increasing lens coloration (light brown 0.33 +/- 0.17 vs dark brown 0.52 +/- 0.35 micromol/g dry mass, p=0.032). Diabetic patients seem to have both increased zinc and iron contents in the lens compared to nondiabetic subjects (zinc: 0.45 +/- 0.42 vs 0.40 +/- 0.22 micromol/g dry mass; iron: 0.12 +/- 0.10 vs 0.08 +/- 0.05 micromol/g dry mass). These data suggest a possible influence of the lens zinc and iron content on the development of lens opacification. Especially advanced forms of cataract and dark brown colored lenses show significantly increased zinc and iron content.

Adult↗
PubMed2002

The correction of anemia in severe resistant heart failure with erythropoietin and intravenous iron prevents the progression of both the heart and the renal failure and markedly reduces hospitalization.

Both Congestive Heart Failure (CHF) and Chronic Renal Failure (CRF) are increasing steadily in the community. We propose that there is a vicious circle established whereby CHF and CRF both cause anemia and the anemia then worsens both the CHF and CRF causing more anemia and so on. We call this the Cardio Renal Anemia (CRA) syndrome. By the combination of active treatment of the CHF and control of the anemia with subcutaneous erythropoietin and intravenous iron, the progression of both the CHF and the CRF can be slowed or stopped in most cases, the quality of life improved and the need for recurrent hospitalization reduced. This will involve cooperation between internists, cardiologists, and nephrologists to allow early and maximal therapy of both the CHF and the anemia.

Aged↗