PubMed HealthSearch

Biomedical subjects

S Wolf

Publications and source records attributed to S Wolf.

At least 19 recordsLinked to original sources

The conus medullaris: time of ascendence to normal level.

This study was intended to determine the level of the conus medullaris in normal babies. We examined 114 healthy infants using high resolution ultrasound which identified the spinal cord and the tip of the conus medullaris. This method provided a good analysis of the level of the conus medullaris so that we could assess the rate of ascent to L1/2. The range of the conus level for all children was at TH12/L1 interspace to L4.78% of babies aged between the 30th and 39th postmenstrual week had the tip of the conus medullaris between L2 and L4.84% of babies aged between the 40th and 63rd postmenstrual week had their conus level between TH12/L1 and L1/2 interspace. In one girl aged 53 weeks the tip was found at L4. Ultrasound is a reliable method to observe the development of the conus level in young infants and to identify a tethered cord.

Female

[Retinal circulation and current blood glucose value in diabetic retinopathy].

In 42 type II diabetic patients with nonproliferative diabetic retinopathy the arm-retina time (ART) and arteriovenous passage time (AVP) were measured by means of videofluorescein angiography. Glycosylated hemoglobin (HbAlc) as a parameter of longterm diabetic control and the blood glucose level were determined. The ART in the diabetics was similar to the ART of normals and the AVP was significantly prolonged. HbAlc level ranged between 5.6 and 12.2% (8.6 +/- 1.7%) and the blood glucose level between 4.5 and 22.9 mmol/l (11.4 +/- 4.5 mmol/l). Significant correlations were found between AVP and blood glucose (r = 0.37) and between AVP and HbAlc (r = 0.49). No correlation was found neither between ART and blood glucose nor between ART and HbAlc. A multiple stepwise regression analysis shows that of both investigated parameters HbAlc is the predicting variable for AVP. These results show that in diabetic patients the retinal blood flow is more influenced by the longterm diabetic control than by the blood glucose level at the time of examination.

Aged

Preservation of hearing in bilateral acoustic neurinomas by deliberate partial resection.

With the aim of preserving hearing, 20 acoustic neurinomas in 17 patients with neurofibromatosis 2 were intentionally submitted to an incomplete (80%) tumour removal. In 12 cases this was an operation on the last hearing ear with total deafness of the contralateral ear. If an auditus existed in both ears the better hearing ear was selected for the primary intervention. Early audiological controls evidenced residual hearing in 19 of the 20 cases operated on by the enlarged middle fossa approach, which was utilized inspite of the tumour diameters being between 1 and 6 cm in the cerebello-pontine angle. The oncologic and functional follow-up over 1 to 7 years showed different patterns of slow progression of hearing loss and of persistent auditory function over 2 to 7 years. Facial nerve function was excellent in 16 of the 18 controlled cases. Continued CT or MRT imaging revealed no signaling in 2 cases, constant tumour sizes in 10 cases and slow progression in 3 cases. With regard to the importance of an auditory communication in the younger adult, the described treatment modality appears to be the first choice method.

Adult

Secondary plasmodesmata are specific sites of localization of the tobacco mosaic virus movement protein in transgenic tobacco plants.

Expression of the tobacco mosaic virus 30-kD movement protein (TMV MP) gene in tobacco plants increases the plasmodesmatal size exclusion limit (SEL) 10-fold between mesophyll cells in mature leaves. In the present study, we examined the structure of plasmodesmata as a function of leaf development. In young leaves of 30-kD TMV MP transgenic (line 274) and vector control (line 306) plants, almost all plasmodesmata were primary in nature. In both plant lines, secondary plasmodesmata were formed, in a basipetal pattern, as the leaves underwent expansion growth. Ultrastructural and immunolabeling studies demonstrated that in line 274 the TMV MP accumulated predominantly in secondary plasmodesmata of nonvascular tissues and was associated with a filamentous material. A developmental progression was detected in terms of the presence of TMV MP; all secondary plasmodesmata in the tip of the fourth leaf contained TMV MP in association with the filamentous material. Dye-coupling experiments demonstrated that the TMV MP-induced increase in plasmodesmatal SEL could be routinely detected in the tip of the fourth leaf, but was restricted to mesophyll and bundle sheath cells. These findings are discussed with respect to the structure and function of plasmodesmata, particularly those aspects related to virus movement.

Cytoplasm

[Movement correction of digital sequence angiographies of the retina].

Retinal hemodynamics can be quantified from videoangiographic image sequences by digital image processing. Intensity changes of dye dilution curves provide dynamics parameters of the local retinal blood flow. The measuring points of dye dilution curves have to be fixed on identical image contents in each image of a complete image sequence. To obtain measurements for every pixel on the retinal surface a motion-compensated image sequence is required. A new method adapted to the compensation of eye motion and movement artifacts in Scanning Laser Ophthalmoscopy in long image sequences (300-500 images) is presented in this paper. To inhibit error propagation of time sequential motion estimation, the eye movement is divided into two dynamic movements components. The method presented permits compensation for eye motion in retinal fluorescein angiographic sequences. Owing to the short calculation times, this algorithm can be used in clinical routine.

Artifacts

The Roseto effect: a 50-year comparison of mortality rates.

OBJECTIVES: Earlier studies found striking differences in mortality from myocardial infarction between Roseto, a homogeneous Italian-American community in Pennsylvania, and other nearby towns between 1955 and 1965. These differences disappeared as Roseto became more "Americanized" in the 1960s. The present study extended the comparison over a longer period of time to test the hypothesis that the findings from this period were not due to random fluctuations in small communities. METHODS: We examined death certificates for Roseto and Bangor from 1935 to 1985. Age-standardized death rates and mortality ratios were computed for each decade. RESULTS: Rosetans had a lower mortality rate from myocardial infarction over the course of the first 30 years, but it rose to the level of Bangor's following a period of erosion of traditionally cohesive family and community relationships. This mortality-rate increase involved mainly younger Rosetan men and elderly women. CONCLUSIONS: The data confirmed the existence of consistent mortality differences between Roseto and Bangor during a time when there were many indicators of greater social solidarity and homogeneity in Roseto.

Adult

Treatment of relapsing peritonitis in pediatric patients on peritoneal dialysis.

Relapsing peritonitis is often due to bacterial colonization of the Tenckhoff catheter and may require removal of the catheter in patients on peritoneal dialysis. The efficacy of a Tenckhoff catheter decontamination procedure was examined in 9 pediatric patients aged 1.5-18 years and compared to the outcome of a historical control group. After repeated dialysate cultures had become negative and cell count was normalized (< 100/ul), intraluminal urokinase (5000 IU/ml) and intraluminal high concentrated antibiotics (vancomycin, fosfomycin, cefotaxim) were instilled sequentially for 3 h and 1 h respectively. This procedure was performed once daily for three days. In addition, the connector was exchanged on the last day. This regimen prevented relapsing peritonitis in all study patients, whereas in the control group in 75.8% of events further relapses occurred, necessitating removal of the Tenckhoff catheter in 7/19 (36.8%) episodes. No side effects of intraluminal urokinase were recorded in any of the patients. We conclude that intraluminal urokinase and intraluminal high concentrated antibiotics combined with connector device exchange are highly effective for prevention of further relapses of peritonitis and reduce the need for Tenckhoff catheter exchange.

Adolescent

Capillary occlusion and secondary angiogenesis: case report.

The first follow-up control 5 days later (14.1.1990) showed a fresh capillary occlusion with massive red blood cell diapedesis. The arteriolar limb of the capillary is filled with erythrocytes up to the occlusion. Since capillary occlusion probably allowed some plasma flow at first, blood cells distal to the occlusion were washed away. After 53 days (8.3.1990) extravasal cells could no longer be made out. At the upper margin of the image a newly formed capillary loop can be seen. The channel of the old capillary seemed to have disappeared. Seventy-three days after occlusion, on 28th of March, the tip of the capillary, already demonstrated on 8th of March, had further grown distally. The capillary had crossed the neighbouring diagonal capillary. Twelve days later (9.4.1990) a remarkable growth connected with formation of a collateral was observed. The new capillary grew in direction of the former capillary channel. On 22nd of April the new capillary had almost got back to its old form. The collateral vessel formed on 9th of April had also grown and could be well distinguished. The different branches were immediately well perfused (mean erythrocyte velocity is v = 0.74 mm/s). The capillary were growing at different speeds. The new capillary had visibly grown by 220 microns over a period of 47 days which corresponds to an average growth of 4.7 microns a day. The capillary was growing fastest between the 9th and 22nd of April. A minimum of growth of 2 microns was observed within the first 11 days of the observation period.

Adult

[The microvasculature and microcirculation of the peri-macular capillary network. New diagnostic possibilities with the scanning laser ophthalmoscope].

The scanning laser technique makes it possible for the first time to perform objective measurements of blood flow velocities in retinal capillaries. This new technique allows for continuous recording of retinal pictures at high resolution. Only the quality of the optical media of the eye limits the resolution of the retinal image. Sequences with a sample frequency of up to 50 images/s can be stored using a digital recorder. In these digital sequences the moving blood stream in retinal capillaries is visible. Segments of high and low fluorescence can be observed moving through the capillary network of the perifoveal capillaries. The flow velocities of these segments can be measured objectively using image analysis. In addition, morphologic information about the perifoveal capillary bed can be obtained by this new technique. Determination of flow velocities and morphological parameters give an objective means of assessing oxygen supply to the macular tissue. Furthermore, the degree of changes in the perifoveal microcirculation may provide objective data for estimating the prognosis of diabetic or senile maculopathy. Further investigation is needed to examine the relationship between changes in perifoveal microcirculation and the development of macular edema in various diseases.

Adult

Nucleotide and nucleic acid metabolism in rat thymocytes during cell cycle progression.

A complete cell cycle of mature, concanavalin A (Con A) stimulated rat thymocytes was documented by analyzing the cell number as well as the content and synthesis of DNA and RNA. Cell cycle progression is accompanied by an elevation of class I, II and III RNA polymerase activities (about 10-fold) in the S phase maximum, 48 h after stimulation. Moreover, maximal cellular contents of DNA, ATP, ADP and AMP were observed at this culture period, whereas the RNA level peaked at 60 h. The synthesis of purine and pyrimidine nucleotides de novo was detected by use of [14C]HCO3-. Maximal incorporation rates of [14C]HCO3- into nucleotides (de novo synthesis) and of [3H]adenine into adenylates ('salvage pathway') occur during the S phase. However, the de novo synthesis rates were markedly lower than those of the 'salvage pathway'. The highest cellular level of the nucleotide precursor 5-phosphoribosyl-1-pyrophosphate (8.4-fold increase) also coincided with the S phase.

Animals

Cloning of a leucine-zipper protein recognized by the sera of patients with antibody-associated paraneoplastic cerebellar degeneration.

Antibody-associated paraneoplastic cerebellar degeneration (the Yo syndrome) is an uncommon disorder in which an immune response is specifically directed against tumor tissue and the cerebellum. Screening of a lambda expression library has resulted in the isolation of cDNA clones that encode the major antigen recognized by serum from these patients. The fusion protein produced by the cDNA clones provides the basis of a simple diagnostic assay for this neurological syndrome. The occurrence of leucine-zipper and zinc-finger motifs in the predicted open reading frame suggests that this protein plays a role in the regulation of gene expression.

Amino Acid Sequence

Mortality among workers at Oak Ridge National Laboratory. Evidence of radiation effects in follow-up through 1984.

White men hired at the Oak Ridge (Tenn) National Laboratory between 1943 and 1972 were followed up for vital status through 1984 (N = 8318, 1524 deaths). Relatively low mortality compared with that in US white men was observed for most causes of death, but leukemia mortality was elevated in the total cohort (63% higher, 28 deaths) and in workers who had at some time been monitored for internal radionuclide contamination (123% higher, 16 deaths). Median cumulative dose of external penetrating radiation was 1.4 mSv; 638 workers had cumulative doses above 50 mSv (5 rem). After accounting for age, birth cohort, a measure of socioeconomic status, and active worker status, external radiation with a 20-year exposure lag was related to all causes of death (2.68% increase per 10 mSv) primarily due to an association with cancer mortality (4.94% per 10 mSv). Studies of this population through 1977 did not find radiation-cancer mortality associations, and identical analyses using the shorter follow-up showed that associations with radiation did not appear until after 1977. The radiation-cancer dose response is 10 times higher than estimates from the follow-up of survivors of the bombings of Hiroshima and Nagasaki, Japan, but similar to one previous occupational study. Dose-response estimates are subject to uncertainties due to potential problems, including measurement of radiation doses and cancer outcomes. Longer-term follow-up of this and other populations with good measurement of protracted low-level exposures will be critical to evaluating the generalizability of the results reported herein.

Cause of Death

Retinal blood flow in diabetic children and adolescents.

A total of 209 diabetic children and adolescents aged 6-17 years (mean, 12.6 +/- 2.3 years) were examined by ophthalmoscopy, video fluorescein angiography and hemoglobin (HbA1c) test. Microaneurysms were found in 26% of the children (ophthalmoscopy, 11%; angiography, 23%). The prevalence of retinopathy was 16% in patients aged 6-10 years, 27% in those aged 11-13 years and 36% in those aged 14-17 years. Only five diabetics aged 11-17 years showed lesions other than microaneurysms (hard exudates, intraretinal hemorrhages or retinal capillar leakage). Retinal blood flow was quantified using video fluorescein angiography. The arm-retina time (ART) and the arteriovenous passage time (AVP) as parameters of the retinal microcirculation were obtained using an image analysing system. The mean value for ART was 9.7 +/- 2.5 s and that for AVP was 1.43 +/- 0.52 s. AVP was significantly shorter in diabetic children and adolescents with good glycemic control (HbA1c, less than 7%; AVP, 1.35 +/- 0.44 s) than in those with bad glycemic control (HbA1c, greater than or equal to 9%; AVP, 1.65 +/- 0.51 s).

Adolescent