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Biomedical subjects

H Beck

Publications and source records attributed to H Beck.

At least 127 records · Page 7Linked to original sources
PubMed1992

Chronic gastritis and the distribution of parietal cells in duodenal ulcer patients and normals.

Pentagastrin-stimulated acid secretion and parietal cell density were studied in 51 patients with duodenal ulcer (DU) and 26 patients without ulcer disease (non-DU). Chronic gastritis was assessed for a comparative study between parietal cell density and grade as well as the extent of gastritis. Parietal cell density was estimated with a high degree of accuracy, since the difference in cell counts of two adjacent biopsies and the inter- and intra-observer variation never exceeded 10%. The density calculated from three regional biopsies was representative for the density of the entire corpus mucosa. Parietal cell density was similar in normal mucosa, superficial chronic gastritis and mild atrophic gastritis, while fewer parietal cells were found in severe chronic atrophic gastritis. Nonuniform distribution of chronic gastritis was more frequent in DU than in non-DU, and may explain the lack of correlation between acid secretion and parietal cell number. If severe chronic atrophic gastritis is found to be localized, parietal cell density investigations will require multiple biopsies.

Chronic Disease↗
PubMed1992

Properties of two voltage-activated potassium currents in acutely isolated juvenile rat dentate gyrus granule cells.

1. The properties of outward currents were investigated in acutely isolated dentate gyrus granule cells at postnatal ages of day 5-7, 10-14, 18-24 (P5-7, P10-14, P18-24) and at adulthood (2-3 mo), with the use of the whole-cell patch-clamp technique. 2. Kinetic analysis and pharmacological properties showed that an A-type K+ current (IA) and a delayed rectifier current (IK) were present in these cells. 3. IA in P10-14 cells activated and inactivated rapidly with a decay time constant of 7.5 +/- 2.1 (SD) ms with command pulses to +30 mV. The removal of inactivation was monoexponential with a time constant of 23.1 ms (holding potential, -50 mV; conditioning voltage steps of varying duration to -110 mV). V 1/2 of the Boltzmann function describing steady-state inactivation was -65.1 +/- 1.8 mV with a slope factor of -6.0. IA was sensitive to 5 mM 4-aminopyridine (4-AP) but not to 10 mM tetraethylammonium (TEA). 4. IK in P10-14 cells displayed a voltage-dependent activation time constant (4.3 +/- 0.8 ms for command pulses to +30 mV and 16.2 +/- 2.4 for command pulses to -10 mV) and a double-exponential decay (time constants 194 +/- 21 and 1,625 +/- 254 ms). The rate constant of removal of inactivation was 332.1 ms. IK showed a reduction by 61.4 +/- 5.3% with 10 mM TEA and was partially blocked by 5 mM 4-AP in a subpopulation of cells. 5. Whereas IA remained stable over time, IK showed a substantial reduction of current amplitude by 67% after 30 min of cell perfusion through the patch pipette. The time course of this reduction was monoexponential with a time constant of 6.9 min and was partly due to a shift in V1/2 of the steady-state inactivation from -79.2 to -99.6 mV. 6. IA and IK remained stable with respect to kinetic properties during ontogenesis. However, the relative contribution and pharmacological properties of the investigated K+ currents varied with age. Although IA dominated in P5-7 cells, IK was prominent in most older cells. Five millimolars 4-AP reduced IA by 40.7 +/- 26.7% in P5-7 cells and blocked IA completely in 80% of investigated P10-14 cells. Similar changes were observed for the effects of 4-AP on IK (18.7% depression in the age group P5-8, 46.1% in the age group P10-14, and 45.7% in adult animals).

4-Aminopyridine↗
PubMed1992

Daily variations of the involvement of beta-receptors in the sympathetic nerve action on glycogenolysis in perfused rat liver.

In perfused rat liver perivascular nerve stimulation (7.5 Hz, 20 V, 2 ms, 5 min) at the liver hilus caused an increase in glucose release, a shift of lactate uptake to output and a decrease in arterial, portal and total flow. The influence of the alpha 1-receptor blocker prazosin and the beta-antagonist propranolol on these nerve effects were studied in the isolated rat liver perfused via both the hepatic artery and the portal vein in three experimental series at 9 a.m., at 2 p.m. and at 8 p.m. 1) The nerve stimulation-dependent increase in glucose output was maximal at 9 a.m. (100%), halfmaximal at 2 p.m. (50%) and very low at 8 p.m. (15%). The alterations in arterial, portal and total flow were similar in all three series. 2) At 9 a.m., at 2 p.m. and at 8 p.m. 5 microM arterial plus portal prazosin nearly completely inhibited the metabolic alterations and blocked the reduction of arterial, portal and total flow by 80%. 3) At 9 a.m. 10 microM arterial, portal and arterial plus portal propranolol inhibited the increase in glucose release to less than 25% and the shift of lactate uptake to output to about 50%. At 2 p.m. this inhibitory effect was not observed, neither by selective arterial or portal, nor by simultaneous arterial plus portal addition of 10 microM propranolol. At 8 p.m. the influence of propranolol could not be studied because of the too small control values. The nerve stimulation-dependent reduction of arterial, portal and total flow was not influenced by propranolol, neither at 9 a.m. nor at 2 p.m.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The dentate gyrus as a regulated gate for the propagation of epileptiform activity.

Properties of the interaction between the entorhinal cortex (EC) and the dentate gyrus were studied in a combined EC hippocampal slice preparation in which most of the fiber connectivity within this structure is intact. Epileptiform activity was induced by lowering extracellular Mg2+ concentration. This caused short recurrent discharges in the hippocampus while seizure-like events (SLE) slowly spread from the site of initiation to neighboring areas. At the end of a SLE, the EC, the subiculum and the neocortical area Te2 discharged in synchrony. This activity could develop into a state of recurrent tonic discharges highly synchronized between the different areas. These discharges were insensitive to treatment with currently available antiepileptic drugs. Although the SLE increased neuronal firing and extracellular potassium concentration in the dentate gyrus, this activity had only moderate effects on the activity generated in areas CA3 and CA1. Removing GABAergic inhibition with baclofen and bicuculline caused the spread of SLE from the EC to the dentate gyrus. Slow inhibitory postsynaptic potentials and intrinsic properties of dentate gyrus granule cells appear to underlie the filtering function of the dentate gyrus.

Afferent Pathways↗
PubMed1992

[Prevention of periarticular ossification following endoprosthetic hip replacement using postoperative irradiation].

The development of heterotopic ossification (HO) after total hip replacement or other surgical hip procedures can considerably impair the functional result and quality of life in up to 73% of all patients. Predisposing high risk factors for heterotopic ossification are severe pre-intra- and/or postoperative hip trauma, previous development of ipsi- and/or contralateral heterotopic ossification, hypertrophic osteoarthritis, active rheumatoid spondylarthritis as well as male sex. Over the past two decades a variety of surgical, pharmaceutical and radiotherapeutic prophylactic measurements have been proposed and tested in clinical trials. Since June 1988, we have treated 77 patients or 80 hips respectively with prophylactic irradiation. Individual risk factors included severe coxarthrosis grade IV, ipsi- or contralateral heterotopic ossification and severe hip trauma. As of July 1991 60 patients with a minimum follow-up of six months could be analyzed using clinical and radiological scoring systems. The patients had been prospectively randomized in two different treatment arms: 32 patients were treated with low dose (LD), five times 2 Gy daily fractions to a total dose of 10 Gy, whereas 28 patients were treated with high dose (HD), ten times 2 Gy (eight patients) or five times 3.5 Gy (20 patients). Operative procedures and individual risk factors were equally distributed in both groups. 23 patients (38% received indometacin three times 25 mg for six weeks, 19 patients (32%) diphosphonate EHDP 20 mg/kg body weight and 18 patients (30%) had no additional medication. 56/60 (93%) patients developed no significant heterotopic ossification and/or remained without impairment of their postoperative radiological and clinical hip status according to the applied Brooker and Harris Scores. Only 4/60 (7%) patients demonstrated treatment failures developing postoperative worsening one grade of Brooker score in two patients and two and three grades of Brooker score in the two others. Only 1/49 patients experienced a treatment failure, when radiotherapy had been initiated before and at postoperative day 4 compared to 3/11 patients initiated after postoperative day 4 (p less than 0.001). 3/32 patients (9.4%) in the LD group and 1/28 (3.6%) in the HD group were scored as treatment failures (nonsignificant). Radiotherapy treatment duration and additional medication had no impact on the outcome. In conclusion postoperative radiotherapy has shown high efficacy in prevention of heterotopic ossification as long as the treatment is initiated within the first four days after surgery. With respect to acute toxicity postoperative radiotherapy seems to be without any competition compared to surgical and pharmaceutical approaches including corticoid, diphosphonate and nonsteroid antiphlogistic drugs.

Adult↗
PubMed1992

["Erlangen Model" titanium socket. Study of the biomechanics of the "Erlangen Mode" titanium socket with and without supporting ring].

A multitude of prostheses are available for the reconstruction of severely arthrotic hip joints--especially for revising total arthroplasty. In order to find out more about the biomechanical efficiency of these special implants, we carried out computerized analyses on how the distribution of stress within the pelvis changes when employing the titanium socket component "Erlanger Modell" [TiAl 5 Fe 2.5], which can be used with a supporting ring in order to transfer the stress on the hip joint to the iliac bone and to the pubic bone in case the acetabulum should not be able to provide the stability needed by the socket. In a procedure described by Herzog, strain gauges are attached to the pelvis of freshly slaughtered cattle at the following sites, transmitting the relative bone expansion and torsion to a multipoint measuring instrument (Linseis L2100) and on-line to a computer: (1) superior ramus of the pubic bone; (2) front edge of the socket at the iliopubic eminence; (3) iliac bone on the outside of the pelvis; (4) socket roof, pars ossis ilei in the small pelvis; (5) socket roof, pars ossis ischii in the small pelvis. The quality of the implantation was monitored by the non-delayed force transmission from the femur through the hip arthroplasty onto the pelvis. With stress varying from 0 to 500 N in steps of 125 N we carried out four complete readings in order to ensure the reproducibility of the measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1991

[Experience with Ender nailing in 671 cases].

Between 1976 and 1987 at the Surgical Department of the University of Erlangen-Nürnberg, 671 fractures of the trochanteric region of the femur were treated by Ender nailing. In 54 cases (8.0%) there were intraoperative complications, in 82 cases (12.2%) postoperative complications occurred. Reoperation became necessary at 57 (8.5%) patients. Because of this complication rate we only see indications for Ender nailing in patients with skin lesions over the fracture site, valgus angulation of the proximal fragment and in the palliative treatment of pathological fractures.

Adult↗
PubMed1991

Absence of xanthine oxidoreductase activity in human myocardium.

STUDY OBJECTIVE: The aim was to examine whether or not xanthine oxidase activity may be a significant source of oxygen derived free radicals in the human heart. DESIGN: Xanthine oxidoreductase activity of human myocardium was assayed in vitro. In addition, tests were performed to assess whether or not endogenous inhibitors of the enzyme were present in myocardial homogenates. The enzyme assay was based on high performance liquid chromatography with electrochemical and/or radiochemical detection of hypoxanthine, xanthine, and urate. SUBJECTS: Measurements were done on (a) isolated perfused rat myocardia and (b) left ventricular needle biopsies and papillary muscles obtained during elective cardiac surgery (chiefly aortic and/or mitral valve replacement and aortocoronary bypass) (n = 105 patients). MEASUREMENTS AND MAIN RESULTS: Homogenisation of human papillary muscles in buffer caused significant accumulation of hypoxanthine but not xanthine or urate. In addition, during incubation of crude myocardial homogenates with exogenous xanthine or hypoxanthine in the presence of NAD+ and/or O2 no production of urate was detected. Likewise, following aerobic incubation of papillary muscle homogenates with 14C-hypoxanthine neither 14C-xanthine nor 14C-urate were formed. Absence of xanthine oxidising activity was also observed with human papillary muscle extracts that were subjected to either ultrafiltration or gel filtration. In contrast, the rat heart was found to contain abundant xanthine oxidoreductase activity. The rat heart enzyme was inhibited by both allopurinol and oxypurinol but remained active when mixed with human papillary muscle homogenates. CONCLUSIONS: These findings show absence of xanthine oxidase and xanthine dehydrogenase activities in human myocardium, indicating that xanthine oxidase is not a source of oxygen derived free radicals in the human heart.

Adolescent↗
PubMed1991

[Postoperative complications and work disability after operation on the adnexa per laparotomy and after pelviscopic surgery].

For estimations of the complaint pattern after comparatable operations per pelviscopiam versus per laparotomiam, in a retrospective study 114 patients after pelviscopic operation and 117 patients after laparotomy were examined. The most important significant differences with an advantage for the pelviscopycally operated patients had been found in asking for postoperative spontaneous miction (84.2% versus 37.2%), spontaneous defecation (68.0% versus 8.1%), the time of completely being free from pain when climbing stair (11.9 compared to 20.8 days), the time when the patient absolutely feel no pain any longer (15.8 compared to 51.7 days), in the average hospitalisation time (3.8 compared to 8.9 days) and the time for unfitness for work (24.5 compared to 48.7 days). Under consideration that also after pelviscopic operations pain occur which are to be treated the present studies confirm the clear improvement of life quality pelviscopic operations.

Adolescent↗
PubMed1991

Can acid secretion be predicted in the duodenal ulcer patient by interpretation of mucosal biopsies?

At gastroscopy 4 biopsies were taken from the oxyntic mucosa in 51 patients with duodenal ulcer. The patients underwent an acid stimulating test by injecting 6 microgram 5-gastrin/kg bodyweight. The parietal cell density in the mucosa of the biopsies was determined by cell counting in a standardized lattice. The method was fully acceptable compared with morphometric analysis of the parietal cell density per volume, and had a low intra- and inter-observer variation. Parietal cell density showed a significantly positive correlation with peak acid output (PAO) in patients with PAO less than or equal to 25 meqH+/h, whereas a correlation not could be demonstrated in patients with PAO greater than 25 meqH+/h. The lack of correlation in patients with high acid secretion reduces the value of the parietal cell counting method in predicting acid secretion in patients with duodenal ulcer disease.

Adult↗
PubMed1990

Differential control of glycogenolysis and flow by arterial and portal acetylcholine in perfused rat liver.

The effects of acetylcholine on glucose and lactate balance and on perfusion flow were studied in isolated rat livers perfused simultaneously via the hepatic artery (100 mmHg, 25-35% of flow) and the portal vein (10 mmHg, 75-65% of flow) with a Krebs-Henseleit bicarbonate buffer containing 5 mM-glucose, 2 mM-lactate and 0.2 mM-pyruvate. Arterial acetylcholine (10 microM sinusoidal concentration) caused an increase in glucose and lactate output and a slight decrease in arterial and portal flow. These effects were accompanied by an output of noradrenaline and adrenaline into the hepatic vein. Portal acetylcholine elicited only minor increases in glucose and lactate output, a slight decrease in portal flow and a small increase in arterial flow, and no noradrenaline and adrenaline release. The metabolic and haemodynamic effects of arterial acetylcholine and the output of noradrenaline and adrenaline were strongly inhibited by the muscarinic antagonist atropine (10 microM). The acetylcholine-dependent alterations of metabolism and the output of noradrenaline were not influenced by the alpha 1-blocker prazosin (5 microM), whereas the output of adrenaline was increased. The acetylcholine-dependent metabolic alterations were not inhibited by the beta 2-antagonist butoxamine (10 microM), although the overflow of noradrenaline was nearly completely blocked and the output of adrenaline was slightly decreased. These results allow the conclusion that arterial, but not portal, acetylcholine caused sympathomimetic metabolic effects, without noradrenaline or adrenaline being involved in signal transduction.

Acetylcholine↗
PubMed1990

Fatty acid and lipopolysaccharide analyses of three Heliobacterium spp.

The cellular fatty acids from Heliobacterium chlorum, Heliobacterium gestii, and Heliobacillus mobilis were analyzed. The fatty acid contents of the three organisms were essentially the same, consisting of large amounts of branched chain and some mono-unsaturated fatty acids. Neither a phenol-water nor a phenol-petroleum ether-chloroform extraction of whole cells yielded lipopolysaccharide.

Bacteria↗