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C Becker

Publications and source records attributed to C Becker.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of protein kinases in rat pheochromocytoma (PC12) cells promotes morphological differentiation and down-regulates ion channel expression.

We have studied morphological differentiation and ion channel expression in PC12 cells under different culture conditions. Differentiation mediated by nerve growth factor (NGF) was compared with that induced by depletion and inhibition of protein kinases (phorbol ester beta-PMA plus staurosporine). Morphological differentiation was similar under both conditions. However, ion channel densities, studied by means of the patch-clamp technique, were enhanced by NGF and reduced by beta-PMA+staurosporine. Similar changes were also observed for omega-conotoxin-sensitive Ca2+ channels by measuring radioligand binding. The decrease in Ca2+ channel density, after treatment of the cells with beta-PMA+staurosporine, resulted in a reduced increase in the intracellular Ca2+ concentration during K+ depolarization. We conclude that morphological differentiation, but not ion channel expression, can occur during depression of protein kinase activities in PC12 cells.

Alkaloids↗
PubMed1992

Lymphokine profile and activation pattern of two unrelated antigen- or idiotype-specific T suppressor cell clones.

Two T suppressor (Ts) clones of different specificity have been analyzed for their lymphokine spectrum. BVI/5 is an I-Ek-restricted bovine serum albumin (BSA)-specific Ts cell clone from a CBA/J mouse tolerized by low doses of BSA. It affects directly or indirectly the function of BSA-specific T helper (Th) cells. The Ts cell clone 178-4 from a BALB/c mouse is I-Ed restricted and recognizes the public J558 Id on B cells. It prevents alpha(1----3)dextran B 1355S (Dex)-specific IgG antibody production and drives Dex-specific J558 idiotype-bearing B cells into an anergic B IgG memory cell state. Both Ts cell clones thus cause specific suppression, yet in different experimental systems using different effector mechanisms. Upon stimulation with concanavalin A or fixed CD3-specific monoclonal antibody, both clones produce high levels of interferon (IFN)-gamma and tumor necrosis factor (TNF) but in contrast to Th1 cells no interleukin (IL)-2. Both clones produce low levels of IL-3 and IL-6 but no IL-4, IL-5 and IL-9. Furthermore, unlike Th2 cells, both clones do not respond to IL-1. The mechanism of the idiotype-specific induction of anergy in Dex-specific B IgG memory cells by 178-4 Ts cells is not yet understood. BVI/5 Ts cells suppress in vitro the BSA-specific proliferation of the BSA-specific Th cell clone 83/1, as well as the response of BSA-primed CBA/LN cells. Whereas the suppressive effect on 83/1 cells is due to IFN-gamma alone the suppression of BSA-specific lymph node cells can be simulated neither by IFN-gamma nor the combination of IFN-gamma and TNF. Thus these mediators cannot account for the antigen-specific suppression by BVI/5 Ts cells in polyclonal in vitro responses from lymph node cells and probably not for the induction of in vivo unresponsiveness.

Animals↗
PubMed1992

[Clinical relevance of whole body skeletal scintigraphy in multiple injury and polytrauma patients].

The provision of care to polytraumatised patients is a particular diagnostic and therapeutic challenge. The examination data of 162 polytraumatised patients were retrospectively investigated to determine the diagnostic gain provided by skeletal scintigraphy with 99mTc-HMDP. It was found that every fresh fracture (with the exception of fractures to the skull) led to a scintigraphically clearly demonstrable remodelling reaction within ten to 14 days. The timing of the examination was of decisive importance for the information yield. Not until about the tenth to 12th day did also those fractures that showed a delayed uptake show adequately signal-intensive areas of uptake in the scintigram. Typical examples were additional fractures of the spine and pelvis in patients immobilised by fractures of the limbs. At this time, with the aim of skeletal scintigraphy, an additional fracture was found in half of all patients, and was subsequently verified radiologically. Additional diagnostic information is independent of the ability of the patient to cooperate. This was of particular importance in the case of the very severely injured and old patients. Skeletal scintigraphy can be employed with equal efficacy to reliably exclude bone injuries. Thus, skeletal scintigraphy if of particular significance in the determination of the extent of bone injury in polytraumatised patients. This applies in particular to the preparation of an expertise. Thus, as in the case of staging of malignomas, the additional performance of bone scanning twelve to 14 days after traumatisation should form part of routine care offered to polytraumatised patients.

Adolescent↗
PubMed1992

[The proton MR spectroscopy of intracranial tumors. The differential diagnostic aspects for gliomas, metastases and meningiomas].

Twenty-two patients with intracranial tumours were examined by MR images and in vivo proton-MR-spectroscopy. The changes of relative concentrations of NAA, PCr/Cr, Cho, and Ins were measured spectroscopically and the amount of these metabolites were related to different tumour groups. Analysis of the results has shown that the spectra from all the tumours differed from normal spectra. All cerebral tumours showed marked reduction of the Pcr/Cho quotient and the NAA/Cho quotient was also reduced. The Ins/Cho quotient for meningiomas and metastases was also lower than in normals; in gliomas of low malignancy the quotient was slightly raised and in gliomas of greater malignancy it was significantly higher than normal. The spectra of cerebral metastases showed unusual high lipid signals of 0.9 ppm and 1.25 ppm. The only common feature for meningiomas was marked reduction of NAA concentration. In summary, localised in vivo proton-MR-spectroscopy can be used clinically to obtain valuable information for the differential diagnosis of gliomas and intracerebral metastases.

Brain Neoplasms↗
PubMed1992

Preliminary studies on the vascular anatomy of the equine superficial digital flexor tendon.

The vascular and microvascular anatomy of normal equine superficial digital flexor tendons was studied by dissection of vinyl-perfused specimens and by microangiography on high detail film. The presence of an extensive intratendinous vascular latticework was confirmed, and a 'nutrient artery' described closely associated with the accessory ligament of the superficial digital flexor tendon (proximal check ligament). Circumferential stripping of the paratenon from the tendon to eliminate afferent vessels was performed bilaterally in three horses and unilaterally in a fourth, followed by a treadmill training regimen. No resulting intratendinous lesions could be documented on gross post mortem and histological examination at three, 10, or 35 days post operatively. There was mild paratendinous proliferation in all instances. In one horse, four intratendinous ligatures were placed within the medial and lateral borders of the contralateral tendon to isolate further from its blood supply a 10 cm segment. Gross lesions at 35 days post operatively included a marked paratendinous response involving the entire 10 cm segment, and a darkened, soft focus within the core of the tendon. Histopathology and electron microscopy demonstrated focal degeneration. It was concluded that the blood supply of the normal equine superficial digital flexor tendon is primarily intratendinous, rather than paratendinous as previously thought. The lesions in one horse similar to those in naturally occurring tendinitis supported a vascular aetiology of the disease, and set the groundwork for studies aimed at the development of a clinically relevant tendinitis model.

Angiography↗
PubMed1992

[Percutaneous removal of residual calculi of the bile ducts by T-drainage tract].

Percutaneous instrumentation under fluoroscopic control via the T tube tract is a minimally invasive technique to remove retained bile duct stones after cholecystectomy. 23 of 25 patients were treated successfully with this method. Two patients needed either percutaneous transhepatic stone-removal or repeat surgery because his residual calculus could neither be removed percutaneously nor endoscopically. In standard situations, the calculi were removed quickly and easily under outpatient conditions. Impacted and large calculi had to be mobilized and fragmented prior to their removal. One patient developed fever, another a mild, transient pancreatitis, no serious complications were observed. In large series, the success rate is 86-95%, the complication rate 3-5%, and the mortality rate 0-0.1%. A relative drawback of the percutaneous technique is the waiting period of approximately 4 weeks which is required for tract maturation. However, this inconvenience is acceptable if we consider that the risk of the percutaneous procedure is less than with endoscopic retrograde sphincterotomy. Therefore, we still favour a primary percutaneous radiologic approach to remove retained bile duct stones.

Aged↗
PubMed1992

[Symptomatic cholecystolithiasis: 1992 therapy options].

Modern treatment of symptomatic cholecystolithiasis requires a knowledge of several nonsurgical and surgical treatment options. Extracorporeal shock-wave lithotripsy and oral bile acid therapy offer the possibilities of noninvasive, outpatient treatment in approximately 20% of all symptomatic gallstone patients at a low complication rate. The percutaneous interventional techniques such as contact dissolution by means of ether or mechanical stone removal may in principle be used in a higher percentage of patients but are considerably more invasive. None of the nonsurgical techniques can exclude the relative risk of gallstone recurrence. Laparoscopic cholecystectomy constitutes a major progress in the surgical treatment of gallstone disease, since it is much less invasive than conventional cholecystectomy and requires a much shorter hospital stay and recovery time. The laparoscopic technique is primarily indicated in patients with symptomatic, uncomplicated cholecystolithiasis. Nevertheless, the range of indications is expanding as experience with this technique increases. Under certain circumstances, laparoscopic cholecystectomy is already being combined with endoscopic sphincterotomy in the presence of bile duct calculi. Conventional cholecystectomy remains the treatment of choice for complicated cases.

Bile Acids and Salts↗
PubMed1992

[Leipzig Medical Society (founded in 1829)].

The Leipzig Medical Society was founded in 1829 by Justus Radius. More than 100 years this interdisciplinary association was a scientific and cultural centre which promoted scientific life and professional training of the municipal physicians and the university staff. Therefore the Leipzig Medical Society contributed to reputation of Leipzig as an cultural and scientific centre during the last years of the 19th and the beginning of the 20th century.

Germany↗
PubMed1991

The community hospital-based stroke programs in North Carolina, Oregon and New York--V. Stroke diagnosis: factors influencing the diagnostic evaluation of patients following acute stroke.

Among the 4129 patients of the Community Hospital-based Stroke Program, 30% had an unspecified stroke diagnosis. Since specific diagnosis and, perhaps, eventual treatment, derives in part from diagnostic testing, we examined the effect of clinical condition, geographic and demographic factors on the incidence of certain diagnostic tests after acute stroke. In this multivariable analysis, race, sex, history of hypertension and history of diabetes did not influence the chance of having any test, but older age strongly reduced the chances of receiving extensive evaluation. When CT scanning was available, the utilization of a CT as well as other diagnostic studies including cerebral angiography, radionuclide brain scan, EEG and EKG was increased. The odds of receiving a CT scan increased if the patient was married, and decreased with a history of previous stroke. A history of previous TIA increased the chance of having a cerebral angiogram while a history of cardiac disease decreased the chance. There were striking regional geographic differences in the use of CT, radionuclide brain scanning and cerebral angiography which may, in part, reflect differences between the availability of these technologies in urban and rural hospitals. These results indicate that evaluation of stroke patients remains heterogenous.

Aged↗
PubMed1991

Comparison of iohexol with barium in gastrointestinal studies of infants and children.

This study evaluates iohexol as a contrast agent in the gastrointestinal tract in children. In the first part of the study, iohexol in concentrations of 180 and 300 mg l/ml was compared in double-blind manner with barium. Sixty-four patients were studied. No significant difference in changes of blood pressure and pulse rate was found between the three groups of patients studied. Diarrhea was significantly more common in the children receiving iohexol than in children receiving barium. The diarrhea was not due to previously identified high-risk factors in the children, nor was it due to concurrent medication. When image quality was assessed in each anatomic region of the gastrointestinal tract, fewer nondiagnostic ratings occurred with barium than with iohexol. With barium, fewer ratings of poor mucosal coating and slightly fewer ratings of suboptimal contrast density occurred. The second part of the study was an open evaluation of iohexol 180 mg l/ml in 18 patients in whom barium was clinically contraindicated. Three of 53 assessments were nondiagnostic. Mucosal coating was poor in 6%, and contrast density was suboptimal in 8% of patients. The results of this study indicate that barium is the preferred contrast agent for routine evaluation of the gastrointestinal tract in children. Good-quality images can be obtained, however, with iohexol in concentrations of 180 or 300 mg l/ml, and iohexol is an excellent contrast agent for evaluation of the gastrointestinal tract in those patients in whom barium is relatively or absolutely contraindicated.

Adolescent↗
PubMed1991

[Clinical pharmacokinetics of lidocaine after intraoral nerve block].

Aim of this study was to show the time course of plasma concentrations of 2% lignocaine with adrenalin at a concentration of 1:100,000. Four retinated third molars were removed in one session in 23 patients. For local anaesthesia in each patient we used 10 ml of Xylocaine 2% (Astra), which is commonly used in dentistry. The plasma-concentration was measured for the first 30 minutes after injection of the local anaesthetic using high pressure liquid chromatography (HPLC). Our results suggest that partially intravascular injection could not be avoided although careful aspiration was carried out before injecting. Neither subjective nor objective adverse central nervous effects were seen in our patients. Nevertheless we consider a peripheral intravenous cannula and ECG-monitoring strongly recommended in all major operations under local anaesthesia.

Adolescent↗
PubMed1991

Fatal injuries at work in California.

We examined deaths due to injury on the job reported from three readily accessible data sources in California for a 1-year period. Of 682 deaths identified as of February 1990 as having occurred on the job in 1983, county coroners identified 607 (89.0%), workers' compensation records identified 294 (43.1%), and the California Occupational Safety and Health Administration investigated 141 (20.7%). Most fatal injuries at work resulted from events that are not covered by current California Occupational Safety and Health Administration standards: transportation vehicle accidents and homicides. Demographic patterns suggest that fatal injuries on the job are nonrandom events, which may be prevented by additions to existing standards or increased enforcement of workplace safety standards and by efforts to target groups at highest risk. Improved surveillance of fatal occupational injuries will require changes in existing reporting mechanisms, similar to those proposed by the US Bureau of Labor Statistics.

Accidents, Occupational↗
PubMed1990

Inhibition of palmitoyl co-enzyme A hydrolase in mitochondria and microsomes by pharmaceutical organic anions.

Rat microsomes and mitochondria were isolated and incubated with selected pharmaceutical organic anions at concentrations of 0, 0.2, 0.5, 1.0, and 2 mM. Activity of palmitoyl CoA hydrolase (PCAH) was shown to be reduced in a dose-dependent manner in microsomes by ibuprofen, valproate, acetyl salicylate, 2,4-dichlorophenoxyacetate (2,4-D), and 4-pentenoate, but not salicylate. Mitochondrial PCAH activity was inhibited by clofibrate, ibuprofen, valproate, and 2,4-D. Mitochondrial oxidative phosphorylation was impaired or uncoupled by each of the mitochondrial PCAH inhibitors. The inhibition of PCAH by some of these agents may lead to fatty acyl CoA accumulation. Very low concentrations of fatty acyl CoA are known to cause mitochondrial uncoupling and increase permeability. This action may play a role in the mitochondrial injury caused by some of these agents or related disease processes.

Animals↗
PubMed1990

Differential expression by nerve growth factor of two types of Ca2+ channels in rat phaeochromocytoma cell lines.

1. Two clones of rat phaeochromocytoma PC12 cells have been used to study the expression of Ca2+ channels and their possible involvement in neuronal differentiation. One clone differentiated morphologically when exposed to nerve growth factor (NGF) for 4 days (PC12 cells), while the other clone was insensitive to NGF, but differentiated morphologically in the presence of ouabain (0.1 mM) for 7 days (PC12-mutant cells). 2. Whole-cell Ba2+ currents through Ca2+ channels were measured in PC12 cells at a test potential (Et) of +10 mV, from two holding potentials (Eh) of -90 and -30 mV (I-90 and I-30). NGF-induced differentiation increased I-90 by 248% and I-30 by 133%. The cells that differentiate in the presence of ouabain had only small, if any, Ba2+ currents that did not appear to change during morphological differentiation or after the addition of NGF. 3. Barium currents in PC12 cells could be separated into two components by selective antagonists. The component of I-90 that could be inhibited by omega-conotoxin GVIA (omega-CgTX) in NGF-differentiated cells was 458 +/- 84 pA (mean +/- S.E.M.), compared with 79 +/- 44 pA in native cells. I-30 was reduced by 50 +/- 17 pA in NGF-treated cells and was virtually insensitive to the toxin in native cells. By contrast, the dihydropyridine (DHP) isradipine reduced I-30 in NGF-treated cells by 30 +/- 8 pA and in native cells by 20 +/- 3 pA. 4. Radioligand binding studies with 125I-omega-CgTX in PC12 cell membrane fragments and in PC12 cells showed a 2- to 3-fold increase in maximal binding capacity after NGF exposure, while mutant cells showed no such change in binding capacity after treatment with NGF or ouabain. Staurosporine inhibited the effect of NGF on 125I-omega-CgTX binding. [3H](+)-isradipine binding capacity was increased 1.8-fold by NGF in depolarized PC12 cells while no change was observed in mutant cells after NGF or ouabain. There was no interaction between omega-CgTX and DHP binding sites. 5. Both the electrophysiological and the binding data indicate a preferential expression of omega-CgTX-sensitive Ca2+ channels (N type) over isradipine-sensitive channels (L type) in PC12 cells treated with NGF. By contrast, ouabain-induced differentiation of a mutant PC12 cell line, that lacks functional NFG receptors, was not associated with the expression of Ca2+ channels.

Adrenal Gland Neoplasms↗
PubMed1990

Community hospital-based stroke programs in North Carolina, Oregon, and New York. IV. Stroke diagnosis and its relation to demographics, risk factors, and clinical status after stroke.

The use of diagnostic tests, the accuracy of stroke type diagnosis, and their relationship to outcome are important from the standpoint of patient management and health care costs. To address this issue, we examined the differences between stroke types in terms of demographics, risk factors, diagnostic tests, and clinical outcome in the 4,129 patients who comprise the Community Hospital-Based Stroke Program. Previous transient ischemic attacks were equally frequent among patients with embolic and those with thrombotic stroke. For all stroke types, previous stroke was as frequent as previous transient ischemic attacks. Hypertension and cardiac disease were the most common risk factors, but 10% of all stroke patients had no recognized risk factors. Intracerebral hemorrhage was most often associated with death (45%). There was a strong direct relation between in-hospital mortality and a decreased level of consciousness at admission. Overall, 30% of patients did not receive a specific stroke type diagnosis; these patients were elderly, usually nonwhite, and often had an altered level of consciousness at admission but had a risk factor profile similar to that of patients who received a specific stroke type diagnosis. In summary, our findings suggest the continued need for physician education about and refinement of stroke type diagnosis.

Aged↗