Biomedical subjects

H Beck

Publications and source records attributed to H Beck.

At least 19 recordsLinked to original sources

PubMed1995

Controlled superfusion of the rat spinal cord for studying non-synaptic transmission: an autoradiographic analysis.

Recently, evidence has been raised that long-term changes in the central nervous system are mediated by extrasynaptic spread of neuropeptides ('volume transmission'). To study the effects of volume transmission in the spinal cord we developed the technique of controlled superfusion of the rat cord dorsum. This paper presents quantitative data about the spread, local spinal tissue concentration and redistribution of (2-[125I]iodohistidyl)neurokinin applied for 15, 30 or 60 min to the spinal cord dorsum in concentrations of 0.05 or 50 microM (10 microliters). Analysis of autoradiograms of sagittal and transverse spinal cord sections was done by computer-assisted densitometry. Under all experimental conditions, the spread of radiolabel into the superfused spinal cord segments reached Rexed's laminae V and VI; maximal spread (1.6 +/- 0.3 mm) was measured after superfusion for 30 min. The amount of radiolabel decreased in ventral direction as a function of distance. Highest tissue concentrations of neurokinin A (NKA) were obtained within the superficial spinal cord up to a depth of 0.5 mm and ranged from 700 to 2000 pmol/g following superfusions for 15 or 30 min with 50 microM NKA. Thus, these tissue concentrations were 25-70 times lower than the concentration of NKA in the superfusate. Since pool content was not exchanged, the radioactivity within the spinal cord was lower after superfusion periods of 60 min than after 15 or 30 min. Detection of radiolabel in blood and urine suggests that capillary clearance is relevant and limits the accumulation of the peptide within the spinal cord tissue and the spread into deeper laminae. The controlled superfusion of the rat cord dorsum is a useful method to mimick the spinal release of endogenous neuropeptides such as NKA during intense noxious stimulation, and it can be employed for versatile investigations of the effects of neuroactive molecules on the processing of sensory information in the intact spinal network.

Animals↗

PubMed1995

[Hemiprosthesis in femoral neck fracture].

From 1968 to 1993 835 hemiarthroplasties were performed at the Department of Trauma Surgery of the University of Erlangen. Until 1984 Moore (297) and Thompson (148) prostheses were implanted. After this period 390 patients were treated with a bipolar headneck replacement. Average age of patients at the time of surgery was 80.2 years from 1968 to 1980 and 83.1 from 1981 to 1993. All hemiarthroplasties were performed due to intracapsular fractures of the femoral neck. 5.9% of the Thompson and Moore prostheses were revised to total hip arthroplasty, the rate of revisions of bipolar prostheses was 4.9%. Main causes of revision for Thompson and Moore prostheses were acetabular erosion and protrusion (5.2%). Revision of bipolar prostheses became necessary because of recurrent luxation in 4.1%. The social status of the patients was examined 1 year after the operation. From 1968 to 1980 67% of the patients lived in their own home or with their families, compared to 39% from 1981 to 1993. The percentage of patients in retirement homes tripled from 9% to 29% for the same period.

Activities of Daily Living↗

PubMed1994

Possible involvement of arachidonic acid and eicosanoids in metamorphic events in Hydractinia echinata (Coelenterata; Hydrozoa).

Upon induction of metamorphosis, larvae of the marine hydroid Hydractinia echinata release [14C]-arachidonic acid from previously labeled endogenous sources. The lipoxygenase inhibitors nordihydroguaiaretic acid and 5,8,11,14-eicosatetraynoic acid inhibited metamorphosis induced by Cs+ and 1,2-sn-dioctanoylglycerol, whereas the inhibitors of cyclooxygenase, indomethacin, and acetylsalicylic acid were ineffective, suggesting a role for lipoxygenase metabolites of arachidonic acid in induction of metamorphosis. Lipoxygenase products in Hydractinia echinata were isolated and identified by gas chromatography/mass spectrometry. 8- and 12-HETE were the most abundant metabolites. In cytosolic fractions from larvae activity of an arachidonic acid metabolizing enzyme, presumably a lipoxygenase, was found. The metabolic product was identified by 1H-NMR and chiral phase HPLC as 8(R)-HETE. Its production was strongly inhibited by NDGA, but not by indomethacin.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1994

Inhibition of cholesterol biosynthesis by allicin and ajoene in rat hepatocytes and HepG2 cells.

Exposure of primary rat hepatocytes and human HepG2 cells to allicin and ajoene resulted in the concentration-dependent inhibition of cholesterol biosynthesis at different steps of this metabolic pathway. At low concentrations of ajoene sterol biosynthesis from [14C]acetate in rat hepatocytes was decreased by 18% with an IC50-value of 15 microM, while allicin was almost uneffective. In HepG2 cells, both compounds significantly inhibited sterol biosynthesis by 14% and 19% with IC50-values of 7 and 9 microM for allicin and ajoene, respectively. This inhibition was exerted at the level of HMG-CoA-reductase as revealed by the absence of inhibition, if [14C]acetate was replaced by [14C]mevalonate as a precursor, and by direct determination of enzyme activity. At somewhat higher concentrations inhibition of cholesterol biosynthesis by both, allicin and ajoene, was also observed at late steps resulting in the accumulation of the precursor lanosterol. Alliin instead was completely inactive. In the case of allicin, small amounts of dihydrolanosterol and 7-dehydrocholesterol were formed at intermediate concentrations of 5-10 microM. From these results it is concluded that a major point of inhibition at the late steps occurs at the level of lanosterol 14 alpha-demethylase.

Acetates↗

PubMed1994

Inhibition of c-Fos protein expression in rat spinal cord by antisense oligodeoxynucleotide superfusion.

Peripheral noxious stimulation leads to a rapid and transient expression of c-fos, c-jun and other immediate-early genes (IEGs) in the spinal cord. However, the role of IEG encoded transcription factors in plasticity of spinal neurons remains speculative. In the present study we have shown that superfusion of rat spinal cord with antisense oligodeoxynucleotides complementary to c-fos mRNA suppresses heat-induced c-Fos protein expression without affecting other members of the Fos and Jun family, thus providing a technique to determine the function of IEGs in vivo.

Animals↗

PubMed1994

Porphyrin studies in TCDD-exposed workers.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been shown to inhibit uroporphyrinogen decarboxylase activity resulting in chronic hepatic porphyria. From a cross-sectional study of 170 workers in chemical industry 68 showed elevated coproporphyrin levels, interpreted as secondary coproporphyrinuria. Three persons suffered from chronic hepatic porphyria in subclinical stages. None of the workers showed an overt porphyria cutanea tarda. A low-grade zinc protoporphyrinemia was observed in three persons. Forty-three of the 170 workers were evaluable for investigating the effect of TCDD on porphyrin levels. No significant correlation was found between TCDD concentration in adipose tissue and the level of uroporphyrin and coproporphyrin. The influence of a chloracne history is described.

Adipose Tissue↗

PubMed1994

Prevention of urethral stricture recurrence using clean intermittent self-catheterization.

OBJECTIVE: To investigate the effect of clean intermittent catheterization (CIC) on prevention of urethral stricture recurrence after internal urethrotomy. PATIENTS AND METHODS: Of 55 men who were randomly selected, 43 completed the investigation. Of these, 21 patients performed CIC weekly for 1 year following Sachse's operation for urethral stricture and 22 patients formed the control group after the same operation. All had an objective examination for urethral stricture every 2 months after surgery. RESULTS: Significantly fewer (P < 0.01) patients developed recurrence of urethral stricture within the first postoperative year in the CIC group (n = 4) compared with the control group (n = 15). No CIC complications were seen, and patients who completed the CIC programme considered the method fully acceptable. CONCLUSION: Weekly CIC is a simple method of reducing the frequency of urethral stricture recurrence after internal urethrotomy.

Adolescent↗

PubMed1994

PCDD and PCDF exposure and levels in humans in Germany.

For nonoccupationally exposed persons, the daily intake via food consumption has been calculated to be 0.35 pg/kg body weight per day for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2.3 pg/kg body weight per day for TCDD equivalents (TEqs). As compared to food, other sources and pathways are of minor importance. Food of animal origin contributes most, although human exposure begins with atmospheric emissions depositing these compounds on plant surfaces. In the meantime, a possible additional body burden from cardboard containers for cow's milk and coffee filters has been practically excluded. Of the 210 existing PCDDs and PCDFs, only 15 2,3,7,8-substituted isomers with a characteristic congener pattern can be found in samples of human origin. In adipose tissue and milk samples, mean levels for 2,3,7,8-TCDD of 7.2 and 3.6 pg/g fat, respectively, and of 56 (range 18-122) and 30 (range 10-72) pg TEqs/g fat, respectively, were determined. Human data revealed a dependency of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) levels on age. In human milk, levels became reduced with the number of children born to mothers and duration of breast-feeding period. The average daily intake for a breast-fed child has been calculated to be 17 pg 2,3,7,8-TCDD/kg body weight per day and 142 pg TEqs/kg body weight per day, respectively. Levels in adipose tissue of infants, even if breast fed, were distinctly lower compared to human milk. In human milk, adipose tissue, and whole blood, PCDD/PCDF concentrations have been found to be equal on a fat-weight basis. Liver fat accumulated PCDD/PCDF with an alteration in the congener distribution pattern, whereas brain, even on a fat-weight basis, showed the lowest concentrations. Elevated or even high levels were found in occupationally exposed persons working in special chemical plants or involved in specific processes. There are limited data suggesting slightly elevated PCDD/PCDF levels are due to long-term consumption of a large share of food produced near point sources with a heavy emission or ingestion of soil or dust from such areas.

Adipose Tissue↗

PubMed1994

[Neuropathology of 20 centenarians. I. Clinical data].

We report a clinical study of 20 patients aged more than 100 years, and deceased in Charles Foix Hospital, Ivry/Seine, France, where they had stayed for 10 days to 16 years (mean: 3.3 years, median: 4 years). Each of them was studied neuropathologically (the results of this study will be published later on). The case selection excluded only those patients whose neuropathological study could not be complete. The prevalence of sensorial deficits was high: 15/20 patients had deterioration of hearing, 8 of them were deaf; 14/20 patients had deterioration of sight, 4 of them were blind. Motor deficits were numerous: 15 patients were not ambulatory. The patients were classified as demented or not, according to the criteria of the DSMIII R (American Psychiatric Association 1987), on the basis of a retrospective evaluation of clinical records, and of an inquiry among the caring staff. Their mental status was also evaluated by the Global Deterioration Scale of Reisberg et al (1985). Five patients had been demented, four had been intellectually normal, and 11 had suffered from mild disturbances of memory or cognitive functions. This series was not representative of the general population of centenarians, but probably of those institutionalized in France. We observed a low proportion of demented patients despite the prevalence expected from epidemiological studies. This is difficult to interpret. The low proportion of dementia in this small sample is not due to the short duration of the course of diseases responsible for dementia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

[Prevention of para-articular ossifications after endoprosthetic hip joint replacement by postoperative irradiation].

In a prospectively randomized study, 137 patients with 141 hips at high risk for heterotopic ossification (HO) received prophylactic radiation therapy (RT). Patients were randomly assigned to a low-dose regimen of five fractions of 2 Gy each (n = 73) or a high-dose regimen of either 10 fractions of 2 Gy each (n = 7) or five fractions of 3.5 Gy each (n = 61). Treatment outcome was assessed by comparing immediately postoperative radiographs with radiographs obtained at least 6 months after hip surgery (Brooker grading score). Positive responses (ie, effective prophylaxis of HO) were seen in 129 (91.5%) hips. Treatment failures were observed in 12 (8.5%). Use of a nonsteroidal antiinflammatory drug (NSAID) lowered the failure rate in both groups. High RT dose with a short duration (< or = 9 days) and use of an NSAID was significantly (p = 0.009) correlated with treatment success. RT delivered within a few days after hip surgery is effective in preventing HO, even in high-risk patients, and provides an alternative of at least equal value for patients with contraindications to long-term medication with either NSAIDs or corticosteroids.

Adult↗

PubMed1994

[Hip dislocation without fracture--a trauma surgery emergency].

Between 1968 and 1990, 26 patients (medium age 24.2 years) with a traumatic hip dislocation without fracture were treated at the Dept. of Trauma Surgery of the University Erlangen-Nuremberg. Only 26.9% of the patients had no further injuries beside the hip dislocation. An early closed reduction was carried out whenever possible. In 96.0% of the cases, radiological acceptable results have been achieved with the closed reduction. In 4.0% an open reduction became necessary. After a period of three to four weeks of extension, the patients had been mobilized to nonweight bearing status. Stress on the injured leg was increased progressively, that full weight bearing capacity was achieved after three months. It was possible to examine 12 of the 26 patients. Good and very good results based on the Merle d'Aubigné score and on the Thompson and Epstein score were obtained in 11 of the 12 patients. The complication seen most often was posttraumatic coxarthritis of the hip. We have not seen any necroses of the head of femur in our patients to date. All our results indicate, that the immediate and careful reposition under anaesthesia seems to be the most important factor in preventing a necrosis of the head of femur.

Adolescent↗

PubMed1994

Detection of soft-tissue infections and osteomyelitis using a technetium-99m-labeled anti-granulocyte monoclonal antibody fragment.

UNLABELLED: Imaging of osteomyelitis and soft-tissue infections can be problematic with currently available agents; bone scans are often false-positive. Indium-111-oxine and 99mTc-HMPAO white blood cell (WBC) scans require ex vivo handling of blood with potential exposure to infectious agents, and 99mTc-antigranulocyte (IgG1) antibodies need 24 hr for final diagnosis. METHODS: We investigated the use of 99mTc-murine anti-granulocyte monoclonal Fab' fragment in 20 patients with suspected osteomyelitis of soft-tissue infections. All patients also had 99mTc bone scans and 111In-oxine or 99mTc-HMPAO white blood cell scans. The final diagnosis was confirmed by culture, biopsy, surgery, follow-up, x-rays, CT or MRI. In vitro studies performed on granulocytes demonstrated no effect on their function when the anti-granulocyte monoclonal antibody fragment was added. RESULTS: Sensitivity, specificity and diagnostic accuracy to detect infection was 88%, 75% and 80%, respectively. All lesions could be detected as early as 1 hr after injection of the antibody fragment. In comparison, WBC scanning had values of 86%, 78% and 81%, respectively. Some lesions could only be detected 24 hr following the injection of labeled WBCs. LeukoScan had three false-positives and WBC scanning had two false-positives. CONCLUSIONS: Immunoscintigraphy with 99mTc-NCA-90 Fab' fragments offers rapid localization of foci, rapid and simple use, a negligible HAMA response rate, no effect on granulocyte function and an accuracy comparable to WBC scanning.

Adult↗

PubMed1994

[The Erlangen Support Ring for management of congenital and acquired acetabular defects. Intermediate term results of 43 implantations].

Between January 1987 and December 1989, at the Department of Trauma Surgery of the University of Erlangen 41 patients were treated at one or both hips with the uncemented hip replacement "Erlanger Modell" including a special supporting ring because of the bad condition of the bone surrounding the acetabular region. In 41 cases the implantation was a revision. 2 patients have not been operated on before. They suffered from congenital hypdysplasia with severe bone destruction at the area of the acetabulum. The supporting ring and the cup are made of the titanium alloy TiAl5 Fe2.5. Using the supporting ring, it is possible to fix the socket within the bone graft and to diminish the pressure exerted on the socket by transferring a lot of stress directly to the iliac bone and the oubic bone. The results of 41 patients (43 joints) ranging from 21 to 57 postoperative months giving an average of 32 months, are very encouraging. 76.6% of the patients feel no or not much pain, 67.4% can walk without hooked stick and 79% can walk a distance of more than 1000 m. The range of movement of the hip joint could be improved, especially abduction and extention. Good results based on patients satisfaction were obtained in 95.4%.

Acetabulum↗

PubMed1993

Prevention of heterotopic ossification (HO) after total hip replacement: randomized high versus low dose radiotherapy.

In a prospectively randomized study 60 hips at high risk for heterotopic ossification (HO) received prophylactic radiotherapy (RT). Randomization was performed between a low dose (LD-RT) of 5 x 2 Gy (arm A: 32 patients) and a high dose (HD-RT) of either 10 x 2 Gy (arm B1; 8 patients) or 5 x 3.5 Gy (arm B2; 20 patients). Relevant patient and risk factors were equally distributed in both treatment arms. 4 (7%) patients developed treatment failures. A short delay of RT after postoperative day (POD) 4 was significantly correlated with failure (p < 0.001). The results suggest no difference in prophylactic efficacy between LD-RT and HD-RT treatment. 2/19 (11%) patients receiving additional diphosphonates and 2/18 (11%) on no medication failed RT treatment, but none on indomethacin did so. In conclusion, immediate postoperative RT has been shown to be an effective prophylactic treatment.

Adult↗

PubMed1993

Radiological examination of the intrathecal position of microcatheters in continuous spinal anaesthesia.

There have been few studies of the intrathecal position of spinal catheters in continuous spinal anaesthesia. This prospective study was designed to examine radiologically the intrathecal position of 28-gauge spinal catheters. We studied the entry into the subarachnoid space and the intrathecal position of 68 spinal catheters. In 50%, the catheters passed in a cranial direction, in 34% the catheters remained at the level of the puncture site and in 16% the catheters were directed caudally. The intrathecal position of the catheters did not depend on the level of the lumbar puncture (P = 0.6246), but was dependent on the position of the patient during insertion of the catheter (P = 0.0093), and on the depth of insertion (P = 0.0099). Our study suggests that patients should be in a sitting position during insertion of a subarachnoid microcatheter and that the depth of insertion should not exceed 4 cm.

Adult↗

PubMed1993

Technical problems with 32-gauge microcatheters in continuous spinal anaesthesia.

Technical problems with microspinal catheters for continuous spinal anaesthesia (CSA) are not unknown. The present case report deals with two unusual technical complications in CSA with 32-gauge spinal catheters. The first case shows a catheter with extraordinary elongation due to breakage of the embedded stylet. The second case shows a tear in the extracorporeal part of the catheter with leakage of the local anaesthetic and consequently failed spinal anaesthesia.

Adult↗

PubMed1993

Nurturing and breast-feeding: exposure to chemicals in breast milk.

All chemicals that are not normal constituents of human milk should be considered undesirable contaminants. In the present review, the following substances detected in human milk are considered: persistent organochlorine pesticides; polychlorinated biphenyls (PCB); polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF); polybrominated compounds; polycyclic aromatic hydrocarbons (PAH); trace elements; mycotoxins; nitrate, nitrite, nitrosamines; nicotine, caffeine, ethanol; and drugs. The levels of most of these substances found in human milk were within a range that would not constitute health hazards for breast-fed infants. For many of these, there is a comfortable safety margin. This applies also to organochlorine pesticides and PCB, particularly since, as a result of their discontinued use, the levels of these compounds have clearly declined in recent years. On the other hand, the aflatoxin burden mediated through breast milk, at least in certain tropical countries, appears to pose a definite health hazard. Detailed reference are given on the contamination of human milk with PCDD/PCDF which has to be considered as a matter of concern from the viewpoint of preventive public health. Although the low PCDD/PCDF levels found in the adipose tissue of infants indicate that there is no appreciable health risk emanating from these substances for breast-fed infants, appropriate measures to reduce the current rate of their emission into the environment have to be taken.

Body Burden↗

PubMed1993

[Results of cementless implantation of 150 "Erlangen Model" hip prostheses of titanium alloy Ti Al5 Fe2.5].

Between March 17, 1984 and August 20, 1987, 142 patients with osteoarthritis of one or both hips were treated by joint replacement with the uncemented "Erlangen" hip prosthesis (Prof. H. Beck/P. Brehm Chirurgie-Mechanik GmbH). The causes of the osteoarthritis varied. Hip replacement was carried out for the following conditions: rheumatoid arthritis including ankylosing spondylitis, aseptic necrosis of the femoral head, including posttraumatic and idiopathic forms, osteoarthritis of unknown origin, osteoarthritis following dysplasia or subluxation of the hips, and loosened cemented hip prostheses (131 primary implantations and 19 revisions). Full weight-bearing was not permitted for 50 days postoperatively, but mobilization and isometric exercises were started 2 days after operation and isotonic exercises were introduced later. Complications included fracture of the femoral shaft during operation and aseptic loosening. Our results in the 142 patients (150 joints) at 32-65 months (average 44 months) after surgery are encouraging. Good results based on patient satisfaction were obtained in 92.7% (81.3% after revision) and poor results in 7.3% (18.7% after revision). Most (90.2%) of the patients can walk without a stick (50.0% after revision), and 90.2% of the patients can walk more than 1000 m (68.8% after revision).

Alloys↗