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Biomedical subjects

S Wolf

Publications and source records attributed to S Wolf.

At least 91 records · Page 5Linked to original sources
PubMed2000

Intensive livestock operations, health, and quality of life among eastern North Carolina residents.

People who live near industrial swine operations have reported decreased health and quality of life. To investigate these issues, we surveyed residents of three rural communities, one in the vicinity of an approximately 6,000-head hog operation, one in the vicinity of two intensive cattle operations, and a third rural agricultural area without livestock operations that use liquid waste management systems. Trained interviewers obtained information about health symptoms and reduced quality of life during the previous 6 months. We completed 155 interviews, with a refusal rate of 14%. Community differences in the mean number of episodes were compared with adjustment for age, sex, smoking, and employment status. The average number of episodes of many symptoms was similar in the three communities; however, certain respiratory and gastrointestinal problems and mucous membrane irritation were elevated among residents in the vicinity of the hog operation. Residents in the vicinity of the hog operation reported increased occurrences of headaches, runny nose, sore throat, excessive coughing, diarrhea, and burning eyes as compared to residents of the community with no intensive livestock operations. Quality of life, as indicated by the number of times residents could not open their windows or go outside even in nice weather, was similar in the control and the community in the vicinity of the cattle operation but greatly reduced among residents near the hog operation. Respiratory and mucous membrane effects were consistent with the results of studies of occupational exposures among swine confinement-house workers and previous findings for neighbors of intensive swine operations. Long-term physical and mental health impacts could not be investigated in this study.

Adult↗
PubMed2000

Porcine kidney microsomal cysteine S-conjugate N-acetyltransferase-catalyzed N-acetylation of haloalkene-derived cysteine S-conjugates.

N-Acetylation of xenobiotic-derived cysteine S-conjugates is a key step in the mercapturic acid pathway. The aim of this study was to investigate the N-acetylation of haloalkene-derived S-haloalkyl and S-haloalkenyl cysteine S-conjugates by porcine kidney cysteine S-conjugate N-acetyltransferase (NAcT). A radioactive assay for the quantification of NAcT activity was developed as a new method for partial purification of the enzyme, which was necessitated by the substantial loss of activity during the immunoaffinity chromatography method. 3-[(3-Cholamidopropyl)dimethylammonio]-1-propane-sulfonate, rather than N,N-bis[3-gluconamidopropyl]deoxycholamide, was used to solubilize the NAcT from porcine kidney microsomes in the revised procedure. The partially purified NAcT was free of detectable aminoacylase activity. Although low acetyl-coenzyme A hydrolase activity was observed, its effect on the assay was minimized by addition of excess acetyl-coenzyme A in the NAcT assay mixture. Attempts to separate the residual hydrolase activity from NAcT by different chromatographic procedures were either unsuccessful or lead to inactivation of NAcT. Most of the cysteine S-conjugates studied were N-acetylated by NAcT. Although the apparent K(m) values for the cysteine S-conjugates studied differed by a factor of approximately 2.5 (124-302 microM), a greater than 15-fold difference in the apparent V(max) (0.75-15.6 nmol/h) and V(max)/K(m) (0.008-0.126 x 10(-3) l h(-1)) values was observed. These data show that a range of haloalkene-derived cysteine S-conjugates serve as substrates for pig kidney NAcT. The significant differences in cytotoxicity of these conjugates may be a result of more variable deacetylation rates of the corresponding mercapturates.

Acetyl-CoA Hydrolase↗
PubMed2000

Factors leading to hydrocephalus after aneurysmal subarachnoid hemorrhage.

OBJECTIVE: The predisposing factors for the development of posthemorrhagic hydrocephalus, requiring shunt implantation, after subarachnoid hemorrhage (SAH) are still not exactly known. Therefore we analyzed the patients with SAH, who were treated in our department with respect to the development of chronical cerebro-spinal fluid (CSF) imbalance, trying to define predictive parameters for this entity. METHODS: All patients presenting with SAH were analyzed retrospectively between September 1992 and July 1998. Special consideration was given to the initial CT scan (cistern index, Fisher grade, bicaudate index) and the requirement for an external ventricular drainage. Other possible predictive factors as age, Hunt & Hess grade, electrolyte disturbances and operative techniques were also evaluated. RESULTS: During the investigation period, 283 patients presenting with aneurysmal SAH underwent surgery. Fifty-two patients (18.4%) required a shunting procedure due to chronic posthemorrhagic hydrocephalus. The mean time interval between the initial bleeding and shunting was 28 days. All of these patients required a significantly longer external CSF drainage (p < 0.001) with a much higher amount of daily drained CSF (p < 0.001). The evaluation of the initial CT scan revealed no correlation between the amount of blood and later shunt dependency. However, there was a significant correlation with the bicaudate index (p < 0.01). CONCLUSION: Chronic hydrocephalus after aneurysmal SAH is an important complication. The recovery-time of shunt dependent patients is definitely prolonged compared to non-shunted patients. Predictive factors of shunt dependency seem to be length and amount of the external CSF drainage, as well as a high bicaudate index.

Adult↗
PubMed1999

Localization of 5-oxo-L-prolinase mRNA in the murine choroid plexus by in situ hybridization.

The gamma-glutamyl cycle is thought to play a significant role in the transport of amino acids between the blood and the cerebrospinal fluid. In the present study we investigated the expression of 5-oxo-L-prolinase, an enzyme of this pathway, in mouse brain and kidney by in situ hybridization using digoxygenin-labeled RNA probes. Expression of 5-OPase mRNA was found in epithelial cells of the proximal tubules in kidney as well as in the epithelium and vascular endothelial cells of the choroid plexus but not in periventricular capillaries.

Amidohydrolases↗
PubMed1999

Immunohistochemical localization of 5-oxo-L-prolinase, an enzyme of the gamma-glutamyl cycle, in porcine brain microvessels.

The immunohistochemical analysis of the distribution of 5-oxo-L-prolinase in porcine brain at the light microscopic level was performed with an antibody raised against the enzyme purified from pig kidney. The present study reveals the specific expression of 5-oxo-L-prolinase in brain capillaries with an average diameter of 4.1+/-0.9 microm, while larger blood vessels remain unstained. Porcine kidney and skeletal muscle show no endothelial-specific staining with the antibody. In some cases, the asymmetrical staining pattern in cross and longitudinal sections of brain microvessels indicate endothelial- but also pericyte-specific expression.

Animals↗
PubMed1999

Kinetic parameters and tissue distribution of 5-oxo-L-prolinase determined by a fluorimetric assay.

5-Oxo-L-prolinase (5-OPase) catalyses the hydrolysis of 5-oxo-L-proline to glutamate with concomitant stoichiometric cleavage of ATP to ADP, a reaction which is known to be part of the gamma-glutamyl cycle-an interrelated series of reactions involved in the synthesis and metabolism of glutathione. As recent studies indicate, this cyclic pathway plays a crucial role in the regulation of amino acid transport. Apparently, the intermediate product 5-oxo-L-proline functions as a second messenger molecule that upregulates the activity of certain amino acid transport systems. Thus, the degradation of 5-oxo-L-proline by 5-OPase leads to the downregulation of this stimulus. In this study, a new sensitive fluorimetric assay for 5-OPase activity was established which is based on the derivatization of glutamate with o-phthaldialdehyde in the presence of thiols and subsequent separation of the products by HPLC. The method is suitable for the screening of chromatography fractions as well as for the determination of the kinetic parameters Km and Vmax of purified 5-OPase. Additionally, it can be used for the measurement of enzyme activity in crude cell extracts and evaluation of tissue distribution.

Amidohydrolases↗
PubMed1999

A new radiolucent system for vertebral body replacement: its stability in comparison to other systems.

Anterior intervention of metastatic lesions of the spine can accomplish relief of pain, spinal decompression, and restoration of spinal stability. Ventral vertebral body replacements have been developed to provide these conditions but there have been problems with loosening at the implant-bone interface, mechanical failure, and X-ray artifacts from the metal. Intraoperative stability of the vertebral body replacement is especially critical to avoid loosening of the implant and to achieve long-term bony incorporation. This study compared the biomechanical performance in vitro of a new radiolucent system for vertebral body replacement to three currently marketed systems. The new system features a composite bioglass-polyurethane body and a new configuration of polymeric fastening hardware. Range of motion, neutral zone, and several interfacial motion parameters were measured under pure moments of 3.75 Nm in the three anatomical directions. The new system provided the significantly highest restraint of motion for all parameters. Mechanically, the new system is preferable at least initially to a sampling of systems representative of those currently used.

Artifacts↗
PubMed1999

Macular translocation for surgical management of subfoveal choroidal neovascularizations in patients with AMD: first results.

BACKGROUND: At present no satisfying treatment for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) is available. Visual results after successful surgical removal of subfoveal CNV are disappointing. This has been explained by a primary dysfunction of the retinal pigment epithelium (RPE) in the macular region and the surgical trauma to the RPE in patients with AMD. Therefore, Machemer and Steinhorst developed a technique for macular translocation after surgical removal of subfoveal CNV. We report our first experiences with this technique in patients with subfoveal CNV secondary to AMD. METHODS: Seven patients aged between 71 and 83 years with subfoveal CNV were included in the study. Visual acuity of the fellow eyes was below 20/400. All patients underwent pars plana vitrectomy. Retinal detachment was produced by subretinal infusion of balanced salt solution and a 360 degrees retinotomy at the base of the vitreous was performed. After removal of the CNV, retinal rotation and reattachment, the retina bordering the retinotomy was coagulated with endolaser photocoagulation. Silicone oil was used as temporary tamponade. RESULTS: In all patients the subfoveal CNV was removed and the macula was translocated by a 15 degrees-45 degrees rotation onto functional RPE. The mean duration of follow-up was 11 +/- 3 months. Initial visual acuity ranged from 20/80 to hand movements. Final visual acuity was 20/100 to 20/400. Initially all patients complained of tilted vision. During follow-up the rotation of the image regressed and was well tolerated by all patients. Complications included the development of retinal detachment in three patients after silicone oil removal, development of a macula pucker, and a significant increase of lens opacity in the phakic eyes. CONCLUSION: In our series rapid improvement of visual function was observed in one patient only, even if the macula appeared ophthalmoscopically and angiographically normal. Vitreoretinal complications occurred frequently during follow-up.

Aged↗
PubMed1999

Dark spots in late-phase indocyanine green angiographic studies in a patient with presumed ocular histoplasmosis syndrome.

PURPOSE: We analyzed indocyanine green (ICG) angiograms in a patient with presumed ocular histoplasmosis syndrome (POHS) complaining about "seeing spots" and decreased visual acuity in order to identify the pathologic process. PATIENTS AND METHODS: A 30-year-old caucasian man with clinical signs of POHS who had previously undergone laser photocoagulation for secondary choroidal neovascularization developed visual disturbances primarily in his temporal visual field. We performed fundus photography, fluorescein angiography and ICG angiography before, during and after the episode of visual disturbance. ICG angiographic findings were correlated to fundus photographs and fluorescein angiograms. RESULTS: Fundus examination, fluorescein angiograms and early-phase ICG angiograms were unremarkable at all time points. However, during the phase of visual disturbance, late-phase ICG angiographic study revealed hypofluorescent lesions in the area representing the visual disturbances. At 1 week follow-up, these hypofluorescent lesions were reduced in size and number; at 6 months follow-up they had completely resolved. CONCLUSIONS: Late-phase ICG angiographic study can provide additional information in inflammatory retinal disease by virtue of identifying areas of choroidal alterations while standard diagnostic examination remain unremarkable.

Adult↗
PubMed1999

Selective inhibition of amino-terminal methionine processing by TNP-470 and ovalicin in endothelial cells.

BACKGROUND: The angiogenesis inhibitors TNP-470 and ovalicin potently suppress endothelial cell growth. Both drugs also specifically inhibit methionine aminopeptidase 2 (MetAP2) in vitro. Inhibition of MetAP2 and changes in initiator methionine removal in drug-treated endothelial cells have not been demonstrated, however. RESULTS: Concentrations of TNP-470 sufficient to inactivate MetAP2 in intact endothelial cells were comparable to those that inhibited cell proliferation, suggesting that MetAP2 inhibition by TNP-470 underlies the ability of the drug to inhibit cell growth. Both drug-sensitive and drug-insensitive cell lines express MetAP1 and MetAP2, indicating that drug sensitivity in mammalian cells is not simply due to the absence of compensating MetAP activity. With a single exception, detectable protein N-myristoylation is unaffected in sensitive endothelial cells treated with TNP-470, so MetAP1 activity can generally compensate when MetAP2 is inactive. Analysis of total protein extracts from cells pulse-labeled with [(35)S]-methionine following TNP-470 treatment revealed changes in the migration of several newly synthesized proteins. Two of these proteins were identified as glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and cyclophilin A. Purification and amino-terminal sequencing of GAPDH from TNP-470-treated cells revealed partial retention of its initiator methionine, indicating that methionine removal from some, but not all, proteins is affected by MetAP2 inactivation. CONCLUSIONS: Amino-terminal processing defects occur in cells treated with TNP-470, indicating that inhibition of MetAP2 by the drug occurs in intact cells. This work renders plausible a mechanism for growth inhibition by TNP-470 as a consequence of initiator methionine retention, leading to the inactivation of as yet unidentified proteins essential for endothelial cell growth.

Amino Acid Sequence↗
PubMed1999

Connections between virus movement, macromolecular signaling and assimilate allocation.

Studies originating with plant viruses led to the concept that plasmodesmata potentiate the cell-to-cell trafficking of viral and endogenous proteins and nucleoprotein complexes. In this article, we develop the theme that, at the tissue/organ level, cell-to-cell trafficking of information molecules enables non-cell-autonomous control over a range of processes, whereas at the organismal level, the phloem serves as an information superhighway. The capacity to deliver proteins and nucleoprotein complexes, over long distances, allowed for the development of a viral surveillance/resistance mechanism, as well as the integration of processes at the whole-plant level.

Biological Transport↗
PubMed1999

Up-training loading responses in older adults.

This randomized, experimental-control group, multiple-observation study examined the ability of older adults to use center of pressure feedback to up-train the vertical loading response (LR) and the impact that such training had on changes in clinical tests of balance. Eleven community ambulators, aged at least 65 years, with no recent history of falls were recruited by convenience sampling. Each group received 6 baseline sessions and 6 control/training sessions, followed by 1 posttest session. All sessions included visual cueing about stance equilibrium followed by 30 randomly timed dynamic, toes-up perturbations (8 degrees, 66 degrees per second). Training consisted of verbal instructions with visual and auditory feedback of a 225 msec response window to shape an increase in total LR following perturbations. Subjects in the experimental group demonstrated a tendency to decrease vertical loading relative to baseline regardless of visual and verbal feedback encouraging strategies to increase it. Specifically, the T3 or 150-225 msec component of the response window showed a decline from session 7 to session 12. Up-training, however, appears to cause a faster rate of rise to the maintenance window, but this event probably occurs too late to correct for a loss of balance. No correlation was found between change in load values and change in performance on clinical balance tests.

Accidental Falls↗
PubMed1999

Prevalence of low bone mass and endocrine disorders in hip fracture patients in Southern Germany.

UNLABELLED: Low bone mass and conditions leading to falls are considered to determine the risk of hip fracture. Bone mass is influenced by underlying diseases and risk factors such as malnutrition and life style habits. In order to evaluate the clinical significance of osteopenia and risk factors in the pathogenesis of hip fracture, we have studied 146 consecutive patients (27 males, 119 females, aged 53-95 years) undergoing rehabilitation shortly after hip fracture (4 cases of hip fracture resulting from traffic accidents had been excluded). We measured bone mineral density (BMD) at the hip (DXA, Hologic QDR 2,000+), evaluated vitamin D status (serum 25-OH-Vitamin D) and nutritional calcium intake (clinical dietician), and searched for endocrine disorders (physical examination and serum hormones). Femoral neck BMD was 0.543 +/- 0.084 g/cm2 in females and 0.635 +/- 0.087 g/cm2 in males (p < 0.01). For both sexes, the values were significantly lower compared to age-matched controls. 88% of the females and 69% of the males had T-Scores below -2.5, thus fulfilling the densitometric WHO criteria of osteoporosis. Nutritional calcium intake was similar in both sexes (804 +/- 330 mg/day in women, 738 +/- 295 mg/day in men), but lower compared to coxarthrosis patients (1080 +/- 436 mg/day). Vitamin D deficiency was prevalent in 69% of the women, and in 55%, of the men with hip fracture. In female hip fracture patients, the serum alkaline phosphatase was significantly higher (194 +/- 82 U/I) as compared to patients with surgery because of coxarthrosis (142 +/- 46 U/I), supporting the view that some degree of osteomalacia and high turnover was present. Primary hyperparathyroidism (pHPT) was newly detected in 1% and hyperthyroidism in 4.3% of the cases. CONCLUSIONS: Hip fracture occurs at higher BMD values in men compared to women suggesting different fracture thresholds. Vitamin D deficiency and low calcium intake are common in hip fracture patients. However, before initiation of vitamin D treatment pHPT should be excluded. Determination of TSH is recommendable in all hip fracture patients.

Aged↗
PubMed1999

[Radiation therapy of occult choroidal neovascularisation (CNV) in age-related macular degeneration (AMD)].

BACKGROUND: Occult choroidal neovascularisation secondary to age-related macular degeneration cause severe visual loss due to exsudation, hemorrhage and fibrovascular scarring. So far, no efficient treatment of this condition could be established. Recently, some publications described an improved prognosis after low-dose radiation therapy of the neovascular membranes. PATIENTS AND METHODS: Patients with occult choroidal neovascularisation as defined by the Macular Photocoagulation Study were inclosed in our study. Irradiation with Photons (10 to 12 MeV) in fractions of 5 x 2 Gy were administered. At three-month follow-up intervals visual acuity a complete ophthalmological examination including visual acuity, fluorescein- and ICG-angiography as well as fundus photography was performed. RESULTS: In our study 64 patients (74 +/- 7 years) with occult CNV secondary to AMD were included. Follow-up was between 3 and 39 months (14.5 +/- 10). Compared to studies who investigated the natural history of this disease, the visual acuity measured in our study did not differ significantly from the natural course. CONCLUSIONS: Our results do not support the general use of radiation therapy in patients with occult choroidal neovascularisation secondary to AMD. However, the controlled multicenter studies might provide a better basis for a general recommendations.

Aged↗
PubMed1999

Musculoskeletal pain and fatigue are associated with chronic hepatitis C: a report of 239 hepatology clinic patients.

OBJECTIVE: The aim of this study was to identify the frequency of fatigue and musculoskeletal pain in hepatitis C compared with other liver diseases. METHODS: Hepatology outpatients were evaluated by questionnaire for musculoskeletal pain and fatigue. Charts were reviewed for diagnoses, aminotransferases, histology, treatment, and presence of hepatitis C by second generation ELISA and/or polymerase chain reaction. The frequency of symptoms in patients with and without hepatitis C were compared. RESULTS: In 239 patients (mean age 46.7 +/- 11.6 yr; 52% male) musculoskeletal pain was present in 70% for 6.7 +/- 8.3 yr and fatigue in 56% for 3.3 +/- 5.1 yr. Backache was the most common complaint (54%), followed by morning stiffness (45%), arthralgia (42%), myalgia (38%), neck pain (33%), pain "all over" (21%), and subjective joint swelling (20%). Diffuse body pain was present in 23% on a pain diagram and was strongly associated with fatigue. There was a significant association between hepatitis C positivity and the presence of musculoskeletal pain (81% of HCV-positive compared with 56% of HCV-negative patients, respectively; p = 0.0001), and fatigue (67% compared with 44%; p = 0.001). Musculoskeletal pain was more frequent among patients with isolated hepatitis C infection than among patients with isolated hepatitis B or alcoholic liver disease (91%, 59%, and 48%, respectively; p = 0.004). Similarly, fatigue was more frequent among patients with isolated hepatitis C than among those with isolated alcoholic liver disease or hepatitis B (66%, 30%, and 29%, respectively; p = 0.004). There was no relationship between musculoskeletal complaints and possible route of acquiring hepatitis C, levels of aminotransferases, liver disease severity on biopsy, or interferon treatment. CONCLUSIONS: Musculoskeletal pain and fatigue are frequent in hepatology clinic attendees, particularly those with hepatitis C and are unrelated to severity of liver disease, route of infection, or interferon therapy.

Fatigue↗