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Biomedical subjects

H Berger

Publications and source records attributed to H Berger.

At least 199 records · Page 11Linked to original sources
PubMed1988

Gonadotropin-releasing hormone (GnRH) pharmacokinetics: peptide hormone pharmacokinetics needs clarification.

The plasma level curves of the peptide hormone gonadotropin-releasing hormone (GnRH) after its intravenous, intramuscular, and intraperitoneal administration into rats were fitted according to a two- (i.v.) and one-compartment model (i.m., i.p.), respectively. From the pharmacokinetic parameters it is concluded that urinary excretion and proteolytic degradation by kidney and liver are not sufficient to fully account for the clearance of the hormone and that, therefore, proteolytic degradation by tissues may play a role for the elimination of GnRH. This may be generally true with other short peptide hormones. The GnRH pharmacokinetics is shown as an example to underline that there presently exist problems of interpreting pharmacokinetic data of peptide hormones and that there is a need for a close interplay between biochemical and pharmacokinetic studies on peptide hormones for their pharmacokinetic behaviour to be understood.

Absorption↗
PubMed1988

[Percutaneous biopsy technic. Aspiration fine needle and cutting biopsy cannula in an experimental comparison].

Guided percutaneous biopsy for cytological or histological diagnosis is well tried. Various types of needles and calibres are available. Only few studies have been performed comparing different needle configurations. Fine needles and cutting needles were evaluated quantitatively and qualitatively in an experimental study obtaining specimens of resected tumours. Weight measurement and preservation of the material were analysed. Material for cytological diagnosis was obtained with all types of needles. Increasing needle size resulted in higher yield of diagnostic tissue. Small-bore cutting needles having an acute bevel angle provide better results in soft or semiliquid tissue. It is not necessary to increase the needle size over 18 gauge.

Biopsy, Needle↗
PubMed1988

[Transthoracic excisional biopsy of focal pulmonary lesions].

The results of percutaneous, fluoroscopically-guided cutting biopsies of focal pulmonary lesions in 126 patients were evaluated retrospectively. In 90% of malignant lesions an exact diagnosis could be made from the material obtained. In 40% of the malignant lesions, histological examination was possible, in addition to cytology. In 87% of these, there was agreement between histology and cytology. Of the cases coming to surgery, 84% of the biopsies proved correct. Specificity was 100%. Multiple punctures were necessary in only 13%. Significant complications occurred in 5%. The cutting biopsy technique has the advantage of producing more biopsy material suitable for histology.

Biopsy, Needle↗
PubMed1988

Evaluation of the efficacy of maduramacin ammonium in combination with roxarsone and avoparcin in caged broiler chickens.

1. The anticoccidial activity of maduramicin ammonium (5 mg/kg food) administered alone or with roxarsone (50 mg/kg food) and/or avoparcin (10 mg/kg food) was evaluated in battery-reared broilers artificially challenged with recent field culture mixtures containing Eimeria acervulina, E. maxima and E. tenella or E. mivati, E. necatrix and E. brunetti. 2. Maduramicin ammonium exhibited a high degree of anticoccidial activity and the addition of roxarsone and/or avoparcin in food at recommended concentrations did not adversely affect the activity.

Animals↗
PubMed1988

Hemodynamic effects of labetalol in patients with combined hypertension and left ventricular failure.

To investigate the safety of labetalol in the treatment of hypertension in patients with heart failure, sixteen hypertensive patients with a history of congestive heart failure and an ejection fraction at rest less than 45%, had measurements of ejection fraction and cardiac output by first pass radionuclide angiography at baseline, at the end of 2 weeks maintenance with labetalol (titrated to the effective antihypertensive dose of 200-1600 mg daily), and in the post-treatment placebo period. On labetalol, heart rate and blood pressure were significantly lower than placebo at rest and the ejection fraction was higher (30 vs 25%) (p less than 0.05). At maximal exercise on labetalol the heart rate and blood pressure were lower than at placebo maximal exercise (p less than 0.05) and the ejection fraction was higher (32 vs 27%) (p less than 0.01). Exercise tolerance was not changed by labetalol. No patient was discontinued from the study because of worsening heart failure. Dizziness was reported in 5 of 16 patients usually at one visit. Dyspnea that was reported in 4 of 16 patients improved with minor adjustments in digitalis or diuretic dose. In conclusion, labetalol reduces blood pressure in hypertensive patients with left ventricular dysfunction without reducing cardiac performance.

Angiography↗
PubMed1988

[Aneurysm of the arteria lusoria. Case report and review of the literature].

Aneurysms arising from an aberrant subclavian artery represent a seldom but dangerous condition, which can be treated successfully when appropriately diagnosed. From 37 patients described in the literature most presented a mediastinal mass and had symptoms like dysphagia, dyspnoe or chest pain. Diagnosis is today possible by contrast-enhanced computed tomography. The aneurysm should be resected to prevent lethal rupture. Left thoracotomy seems to be the appropriate approach in most cases. Reestablishment of blood flow to the right subclavian artery seems not necessary and may be done if ischemia develops in a second procedure by subclavian transposition to the common carotid artery. The case of a 74-year-old women who had resection of an aneurysm in an aberrant subclavian artery is described together with a review of the literature and discussion of the surgical management.

Aged↗
PubMed1988

[Attempt at in vitro decalcification of aortic valves using various types of lasers].

The effects of three types of laser were studied in vitro on calcified aortic valves removed in the course of valve replacement. These were: 1) argon laser; 2) Nd-YAG laser with a long (1 ms) impulse, and 3) Nd-YAG laser with a short (10 ns) impulse. With the first two types of laser, lesions of carbonization and fragments detached from the areas treated were observed. With the 10 ns ND-YAG laser, a mean energy of 100 mj per shot excavated the calcified valves by drilling holes that were 0.5 to 1.5 mm in diameter and had clear-cut non carbonized borders. No residue was found during the procedure: the substance was simply vaporized. The splitting of several calcareous nodules on a valve made it more pliable. If it were possible to transfer this high peak energy onto a flexible optic fibre, the aortic valves could be decalcified by interventional catheterization.

Calcinosis↗
PubMed1988

Preparation of polyethylene glycol-tissue plasminogen activator adducts that retain functional activity: characteristics and behavior in three animal species.

Conditions were defined for the derivatization of recombinant tissue plasminogen activator (rt-PA) with polyethylene glycol (PEG) so as to retain functional activity as a possible means of producing a t-PA species with a prolonged circulating lifetime. Derivatives with a wide range of retention of activities were prepared by varying the concentration and species of activated PEG. The specific activities of the PEG-rt-PA derivatives were dependent on the method of assay. Assays using preformed fibrin gave higher estimates of retention of activity than assays using soluble components. Plasma elimination studies in mice and rats indicated prolonged circulating lifetimes for the radiolabeled PEG-rt-PA derivatives after a rapid clearance and distribution phase; however, the disappearance of functional activity was much more rapid than the disappearance of radiolabeled material. The PEG-rt-PA derivatives appeared to accumulate in tissues above their interstitial fluid concentrations and were rapidly inactivated, apparently by reaction with the plasma protease inhibitors. These results were consistent with the inactivation of the PEG-rt-PA derivatives in rat plasma in vitro. A somewhat longer half-life (t1/2) of the one derivative studied was observed in dogs (t1/2, 16 minutes) as compared with the rat (t1/2, five minutes). This was sufficient to confer thrombolytic activity upon the derivative (administered by bolus injection) in contrast to native rt-PA. The potential of PEG-modified rt-PA as a long-lived thrombolytic agent in humans will depend, however, on whether there will be a further extension of the t1/2 because of a reduction in clearance and/or a reduction in the rate of inactivation.

Animals↗
PubMed1988

[Fine-needle and incisional biopsy technics in the percutaneous puncture of abdominal space-occupying lesions].

Cutting needles for guided percutaneous biopsy of abdominal tumors have been introduced in recent years and provide better results than fine-needle aspiration. A total of 292 biopsies in 273 patients were evaluated retrospectively. The diagnostic accuracy was 83.4% with cutting needles and 54.4% for fine-needle aspiration. The sensitivity in detection of malignancy was 86.8% and 88.6%, respectively. The location of the lesion to be biopsied determined whether CT or US was used for guidance. US control was used in biopsies of the upper abdomen; CT was preferred for guidance in the retroperitoneal space and in the pelvis. The caliber of the cutting needles in transperitoneal or transintestinal biopsy was limited to 19 gauge. The complication risk using cutting needles up to 18 gauge is no higher than for fine-needle aspiration biopsy if suitable access routes are selected.

Abdominal Neoplasms↗
PubMed1987

Peripheral and autonomic nerve function in long-term insulin-dependent diabetes.

In a cross sectional study, motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV), beat-to-beat variation (BBV) at rest and speed of pupillary dilatation (SPD) have been investigated in 127 nonketonuric long-term insulin-dependent diabetics aged 19-72 yr and in age-matched control subjects. 84% of the patients had electrophysiologic abnormalities, 58% had symptomatic peripheral neuropathy, 35% had abnormal cardiac parasympathetic tests and 26% had abnormal pupillary tests. The most frequent pathologic feature was a decreased sural SNCV (66%). Among the patients without symptomatic peripheral neuropathy, 71% showed electrophysiologic abnormalities. MNCV and SNCV in median, peroneal and sural nerves correlated with BBV (p less than 0.005), but only peroneal MNCV was related to SPD (p less than 0.005). There was also a relationship between BBV and SPD (p less than 0.05). Glycosylated hemoglobin (HbA1) levels correlated inversely with median MNCV (p less than 0.001), and SNCV (p less than 0.03), peroneal MNCV (p less than 0.05) and sural SNCV (p less than 0.05). Patients with abnormal peripheral or autonomic nerve function tests or symptomatic peripheral neuropathy had significantly higher HbA1 levels than those with normal tests (p less than 0.04) or asymptomatic patients (p less than 0.01). Median MNCV and SNCV, sural SNCV and BBV deteriorated with age (p less than 0.05) and median SNCV and peroneal MNCV deteriorated with the duration of diabetes (p less than 0.001). Our findings show an association between peripheral and autonomic nerve dysfunction in long-term insulin-dependent diabetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Catheter embolization of intrarenal arteriovenous fistula formations].

Catheter embolization of renal arteriovenous fistulas is an effective alternative treatment to surgery; general anaesthesia is not necessary and the hospitalization is limited to 2-3 days. Suitable catheters, permanent occlusion material, such as butylcyanoacrylate, and balloon occlusion technique provide a safe and successful embolization even in cases with massive arteriovenous malformations.

Adult↗
PubMed1987

Pharmacokinetics of gonadotropin-releasing hormone and stimulation of luteinizing hormone secretion after single dose administration of GnRH incorporated into liposomes.

The properties of liposomes as a carrier for sustained release of gonadotropin-releasing hormone (GnRH) was investigated. A mixture of egg-phosphatidylcholine/egg-phosphatidic acid, binding GnRH with high capacity, was used for preparation of GnRH-carrier liposomes, which were of the multilamellar type in most experiments. As test animals we used rabbits and pigs, the last mentioned for checking the LH4 response to GnRH-injections, which was via the i.m. route throughout in this investigation. By measuring the kinetics of removal of GnRH from the injection site and by following the GnRH invasion into the circulation, it was demonstrated that GnRH release from liposomal depots is strongly slowed down, compared with injections of the free hormone. Further, plasma levels of GnRH were detectable up to 8 h generally, sometimes up to 20 h after injection. However, a considerable portion of GnRH bound to multilamellar liposomes was released so slowly in our case, that the concentration decreased even below the RIA detection limit. This appears clearly from our kinetic data. For this reason the resorption of GnRH from liposomes seems to be less efficient than after i.m. injections of the free hormone. With pigs also the LH response to the injection of GnRH-liposomes was relatively poor. Apparently, biological activity is missing with very low GnRH concentrations. The results furnish good information on how to modify the liposome carrier in order to produce preparations with changed rates of GnRH release.

Animals↗