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Biomedical subjects

J Vogel

Publications and source records attributed to J Vogel.

At least 127 records · Page 7Linked to original sources
PubMed1995

[First clinical experience with a new nitinol stent in the biliary system].

PURPOSE: To evaluate the clinical usefulness of a new nitinol biliary stent (Memotherm) in patients with malignant biliary obstruction. 32 self expanding nitinol stents were applied in 17 patients. The following parameters were investigated: Difficulty of placement, lateral stability and patency over an observation time between 3 weeks and 11 months. RESULTS: In 29/32 stent application could be performed with high precision. In 3/32 we observed a displacement about 1 cm--according to the optimal stent position. Stent shortening was about 5 mm in 31/32 stents, secondary shortening only occurred in one patient with primarily distracted stent design. Lateral stability was sufficient in 21/25 stenoses with the consequence that dilatation was only performed in 4 cases. Average stent patency was 4.8 months, the average survival 5.1 months. Because of his special design, this stent may not be used for a stenosis with angulation higher than 90 degrees. CONCLUSION: Basing on a small calibre introducing system, easy placement, predictable minimal shortening and good lateral stability, the Memotherm seems an interesting alternative to other metal stents.

Alloys↗
PubMed1995

[Radiation exposure during digital hysterosalpingography: how much is due to fluoroscopy?].

PURPOSE: To determine the proportion of radiation exposure from fluoroscopy during the performance of hysterosalpingography, using a digital image intensifier. MATERIAL AND METHOD: 20 women with primary or secondary sterility were examined. The total radiation dose was measured and the proportion due to fluoroscopy was determined. The use of a computer programme permitted accurate differentiation of the dose obtained by fluoroscopy and radiography. Total mean radiation dose was 256 cGy x cm2; fluoroscopy contributed 187 cGy x cm2. On average, fluoroscopy contributed 69% of total radiation dose. CONCLUSION: During hysterosalpingography with a digital image intensifier, fluoroscopy should be as brief as possible since it contributes most of the radiation dose.

Adult↗
PubMed1995

Patterns of capillary plasma perfusion in brains in conscious rats during normocapnia and hypercapnia.

The present study aimed to investigate the distribution pattern of plasma flow velocities in brain capillaries. We tested the hypothesis that plasma flow velocities are heterogeneous in the brain capillaries of normocapnic conscious rats and become more homogeneous during increased cerebral blood flow induced by hypercapnia. We developed a method that makes it possible to detect the distribution pattern of plasma flow velocities from the intravascular dye concentrations measured in different capillaries. Evans blue was injected intravenously as a bolus, and 3 to 4 seconds later the rats were decapitated. During this period, a steep increase in arterial dye concentration was verified by frequent arterial blood sampling. Under such conditions, divergent plasma flow velocities in different capillaries yield unequal intravascular dye concentrations. Dye concentrations were measured in several hundred capillaries of brain cryosections using quantitative fluorescence microscopy based on calibration curves obtained from anesthetized rats. The results show a high degree of variation in the intravascular dye concentration during normocapnia. During increasing stages of hypercapnia, the variation was gradually reduced. The coefficient of variation (SD/mean-100) of intracapillary dye concentration decreased from 76% at normocapnia to 22% at extreme hypercapnia (PCO2 of 87 mm Hg), thus showing an inverse correlation with arterial PCO2 (r = .97). The heterogeneity of intravascular dye concentrations observed in the present experiments indicates heterogeneous velocities of plasma perfusion in different brain capillaries during normocapnia and a more homogeneous distribution pattern during hypercapnic hyperemia.

Animals↗
PubMed1995

[Results of catheter embolization of renal cell carcinoma].

PURPOSE: We pointed out the value of catheter embolisation of kidney tumours. METHODS AND PATIENTS: We treated 42 patients with kidney tumours. For peripheral embolisation we placed Histoacryl or Ethibloc into the kidney artery via a transfemoral catheter. 33 patients had haematuria. 8 patients were lost for follow up. 26 patients were treated by embolisation alone and 8 patients were treated before nephrectomy. RESULTS: Haematuria was stopped in 98% and never reoccurred. The intraoperative blood-loss was 600 ml on average. 55% of patients treated by embolisation alone died within the first year. 51% of patients suffered from a slight postinfarction syndrome. One patient died of sepsis and one had pulmonary insufficiency due to AV shunt and pulmonary embolism. CONCLUSIONS: Peripheral embolisation of kidney tumours can be used successfully and is minimal invasive, in case of haematuria and pain. The perioperative risk is reduced due to limited blood loss.

Adult↗
PubMed1995

[Alveolar echinococcosis of the liver--computerized tomography findings].

In order to ascertain the typical computed tomographic findings of hepatic alveolar echinococcosis, 24 computed tomograms of 19 patients were evaluated. The liver was involved in all cases whereas the diaphragma was infiltrated in 32%, and the retroperitoneal area in 42%. The right liver lobe was affected in 65%. Both before and after intravenous bolus contrast medium administration, the lesions were mainly inhomogeneous and of low density; a masking of the lesions due to the contrast medium administration was not observed; the enhancement pattern was irregular. Calcifications were detected in 96% of the cases, cystic structures in 50%, and cholestasis in 54%. On the basis of the crucial finding of calcifications in combination with the other typical observations, CT seems to be very suitable for the evaluation of hepatic alveolar echinococcosis.

Adult↗
PubMed1995

Low pretreatment gallbladder stone densities at computed tomography predict rapid stone clearance following extracorporeal shock wave lithotripsy.

The importance of routine computer tomographic (CT) stone analysis in optimizing the therapeutic outcome after extracorporeal shock wave lithotripsy (ESWL) remains controversial. The aim of the present prospective study was to seek a correlation between CT findings and stone clearance rates after ESWL in 159 patients. One hundred fifty-nine symptomatic patients (116 females, 43 males) with solitary radiolucent gallbladder stones underwent CT for stone analysis before lithotripsy. In Group I (<50 HU, n=104), stone clearance was achieved in 55.8% of patients within 6.11+/- 6.95 months; in Group II (51-100 HU, n = 28), in 50.0% of patients within 11.2 +/- 10.3 months; in Group III (>100 HU, n = 27) in 29.7% of patients within 9.60 +/- 6.96 months. The mean follow-up period was 17.9 +/- 10.0 months. Patients in Group I showed a significantly higher rate of stone clearance than those in Groups II and III (p < 0.001) as well as a significantly shorter time for the achievement of total stone clearance than either of the other groups (p < 0.001). The authors conclude that CT stone analysis provides a more accurate method of selecting patients suitable for ESWL and may be of importance in predicting the expected length of time for achieving complete stone clearance.

Absorptiometry, Photon↗
PubMed1994

A comparison of pipecuronium with pancuronium on haemodynamic variables and plasma catecholamines in coronary artery bypass patients.

Pipecuronium bromide, a new neuromuscular relaxant with steroidal structure, is devoid of effects on the autonomic nervous system and may be useful in patients where haemodynamic stability is mandatory. However, tracheal intubation may alter this haemodynamic profile. Therefore, we carried out a prospective double-blind study in 30 patients undergoing coronary artery bypass surgery with the purpose (1) of determining if intubation influenced the haemodynamic stability in patients paralyzed with pipecuronium and (2) of comparing plasma catecholamine concentrations after pipecuronium with those after pancuronium. Thirty patients were randomized into two groups receiving either pipecuronium 100 micrograms.kg-1 or pancuronium 150 micrograms.kg-1 after induction of anaesthesia with midazolam and fentanyl. Haemodynamic variables and plasma catecholamines were measured before and after induction, after the muscle relaxant three times and twice after intubation. After anaesthesia induction decreases in heart rate (HR), mean arterial pressure (MAP) and cardiac index (CI) were observed in both groups. These haemodynamic variables were unchanged after pipecuronium whereas after pancuronium HR increased from 53 +/- 11 b.min-1 to 64 +/- 9 b.min-1 after induction (P < 0.05) and CI from 2.5 +/- 0.5 L.min-1 to 3.0 +/- 0.8 L.min-1 (P < 0.05). Furthermore ECG signs of myocardial ischaemia appeared in four patients after pancuronium and the decay of plasma norepinephrine concentration was slower than with pipecuronium. We conclude that pipecuronium given after induction of anaesthesia is free of sympathomimetic or vagolytic activity and does not influence haemodynamic variables for up to ten minutes after tracheal intubation.

Anesthesia, Intravenous↗
PubMed1994

Glucoseoxidase from Aspergillus niger in reverse micelles: pH and wo dependence.

The well known enzymatic method for the determination of glucose in aqueous solution with the system glucose oxidase/peroxidase/o-dianisidine was modified in a way that enables the quantitative determination of glucose in various reverse micellar systems. For instance in the 0.1 M sodium-bis-(2-ethylhexyl)-sulfosuccinate/n-octane system the useable glucose measuring range is between 10 and 70 micrograms glucose per 3 ml micellar solution. Investigations concerning the influence of the pH-value and the wo-value on the enzyme activity of glucose oxidase in the system 0.1 M sodium-bis-(2-ethylhexyl) sulfosuccinate/n-octane led to a shift of the pH-optimum from pH 5.5-6.0 in aqueous solution, to pH 4.0, in reverse micellar solution. The bell-shaped wo-dependence of the enzyme activity, typical for many other enzymes, was not found for glucose oxidase at pH 4.0, and was less clearly visible at the other investigated pH-values with an optimum at wo = 5.6.

Aspergillus niger↗
PubMed1994

Sound localization in chinchillas. I: Left/right discriminations.

The ability of chinchillas to localize sound was examined behaviorally using a conditioned avoidance procedure in which the animals were trained to discriminate left from right sound sources. Their minimum audible angle was 15.6 degrees for 100-ms broadband noise making them one of the more accurate rodents, although they are not as accurate as primates and carnivores. Thresholds obtained for filtered noise stimuli demonstrated that chinchillas are equally accurate in localizing either low- or high-frequency noise. Further, they are able to use both interaural phase-difference and interaural intensity-difference cues as demonstrated by their ability to localize both low- and high-frequency pure tones. Finally, analysis of the chinchilla retina supports the hypothesis that the role of auditory localization in directing the eyes to sound sources played a role in the evolution of auditory spatial perception.

Acoustic Stimulation↗
PubMed1994

Prostaglandin F2 alpha modulates responses of single cultured mesangial cell to arginine vasopressin.

The role of prostaglandin F2 alpha (PGF2 alpha) interaction with arginine vasopressin (AVP) in modulating intracellular Ca2+ homeostasis was studied. Examinations were done on single cultured mesangial cells loaded with fura-2. Pretreatment of cultured mesangial cells during 1 min with different concentrations of PGF2 alpha (10(-5)-10(-8) M) caused a significant prolongation of [Ca2+]i transients after subsequent AVP applications. The observed effect of a prolonged sustained phase was not influenced by the temporal sequence of AVP stimulation after preincubation with PGF2 alpha: the signal was modulated in nearly the same way after 5 min delay as after nearly simultaneous application of AVP and PGF2 alpha. Measurements in Ca(2+)-free medium showed that the prolonged sustained phase of [Ca2+]i transients after AVP applications in cells pretreated with PGF2 alpha was mostly due to Ca2+ release from intracellular store(s). Pretreatment of the cells with PGF2 alpha also greatly enhanced the % of AVP responsive cells. Even at concentrations of AVP as low as 10(-10) M about 30% of cells pretreated with PGF2 alpha responded with the fast [Ca2+]i rise. Thus, present studies showed that PGF2 alpha specifically modulates [Ca2+]i transients after AVP stimulation and enhances sensitivity of mesangial cells to AVP. The results help to identify PGF2 alpha participation in the cellular regulatory mechanisms of microcirculation and filtration in the kidney.

Animals↗
PubMed1994

Dynamic magnetic resonance imaging of the contralateral testis in patients with malignant tumor of the testis.

OBJECTIVES: Dynamic magnetic resonance imaging (MRI) was tested using a dynamic technique to evaluate the possibility of differentiating between normal contralateral testes and testes with a carcinoma in situ. METHODS: Since March 1990, 20 volunteers and 21 patients with a malignant tumor of the testis were examined in a field strength of 1.5 Tesla (Philips Gyroscan S15) with a multislice T1-weighted fast field echo sequence before and every 63 seconds after the injection of 0.1 mmol/kg gadolinium-diethylenetriamine pentaacetic acid. RESULTS: Significant differences (p < 0.001) in signal changes of contralateral testes were detected in dynamic MRI. This increased signal enhancement is detected even 45 months after orchiectomy in the contralateral testes. The signal increase is reduced in follow-up controls. These observations are explained by an increased perfusion which seems to be induced after a postoperative irritation, an unspecific inflammation, or postoperative bleeding. CONCLUSIONS: To avoid false-positive diagnoses of tumors or carcinomata in situ in contralateral testes, these increased enhancements caused by postoperative reactions have to be kept in mind.

Adult↗
PubMed1994

A yeast RNA-binding protein shuttles between the nucleus and the cytoplasm.

RNA-binding proteins have been suggested to move in association with RNA as it leaves the nucleus. The NPL3 gene of the yeast Saccharomyces cerevisiae encodes in nuclear protein with consensus RNA-binding motifs and similarity to heterogeneous nuclear ribonucleoproteins and members of the S/R protein family. We show that although Npl3 is located in the nucleus, it can shuttle between nuclei in yeast heterokaryons. In contrast, other nucleus-targeted proteins do not leave the nucleus under similar conditions. Mutants missing the RNA-binding motifs or the N terminus are still capable of shuttling in and out of the nucleus. Npl3 mutants missing the C terminus fail to localize to the nucleus. Overproduction of Npl3 in wild-type cells shows cell growth. This toxicity depends on the presence of series of unique repeats in the N terminus and localization to the nucleus. We suggest that the properties of Npl3 are consistent with it being involved in export of RNAs from the nucleus.

Biological Transport↗
PubMed1994

[Abdominal emergencies in patients with AIDS].

This is a report on five patients suffering from AIDS who underwent emergency abdominal surgery: One patient with gangrenous appendicitis, three with a small bowel perforation and a third with a colonic bleeding. The first outlived the appendectomy by seven month; the second and the third the small bowel resection by eight weeks resp. by 10 weeks. The fourth died four weeks after hemicolectomy and a relaparotomy with colonic resection for profuse bleeding. The fifth died because of infiltration of the heart by a malignant lymphoma. None of the patients developed any complications due to surgery. A review is given on emergencies caused by abdominal diseases which a surgeon must be aware of in patients with AIDS. The palliative character of surgery in these patients is stressed.

AIDS-Related Opportunistic Infections↗
PubMed1994

[5 years follow-up study of stroke patients over 65 years of age].

A total of 289 stroke patients over age 65 were followed-up 5 years post-discharge from in-patient rehabilitation. Predictors of the course following discharge are investigated and geriatric rehabilitation assessed based on data gathered during in-patient rehabilitation as well as follow-up findings. 40% of the patients were alive 5 years post-discharge; the average annual death rate of 14.6% had been three times higher than among a control group. 67% are living in their own home, 21% in a nursing facility, and 12% in a residence for the elderly; only 3 of the surviving patients had to move to a nursing home post discharge. The patients' independence had reduced by an average 5 points on the Barthel index. Negative predictors for survival had been the presence of cardiac disease, Diabetes mellitus, psycho-organic syndrome and depression at discharge. However, as is the case for age as such, these conditions do not affect survivors' functional outcomes. Two thirds of the patients consider their state of health as constant or improved; only one fifth were rated as having a poor quality of life. The data gathered for the follow-up patients show that geriatric stroke rehabilitation is worthwhile.

Activities of Daily Living↗