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Biomedical subjects

H H Wolf

Publications and source records attributed to H H Wolf.

At least 19 recordsLinked to original sources
PubMed1990

Infection prophylaxis in neutropenic patients with acute leukaemia--a randomized, comparative study with ofloxacin, ciprofloxacin and co-trimoxazole/colistin.

Preliminary results are presented of an ongoing, prospective, randomized, study comparing ofloxacin, ciprofloxacin and co-trimoxazole/colistin for the prevention of infection in patients with acute leukaemia. The results for 59 patients (median age 47 years, range 21-72) included 88 episodes of neutropenia, each associated with a course of cytotoxic therapy. The main factor measured was the time elapsed from the beginning of neutropenia (neutrophils less than 500/microliter) until the first infectious febrile episode. The median time for the period was 12 days (range 1-56) for the cotrimoxazole/colistin group, 15 days (range 1-38) for the ofloxacin group and 20 days (range 1-36) for the ciprofloxacin group (differences not significant). Microbiologically proven major infections occurred in 10/27 treatment courses with co-trimoxazole/colistin 7/31 courses with ofloxacin and 7/30 courses with ciprofloxacin (P not significant). These were mostly due to Gram-positive cocci. There were no Gram-negative infections in the quinolone groups compared with one major Pseudomonas aeruginosa infection in the co-trimoxazole/colistin group. No Pneumocystis carinii infections were encountered. Adverse reactions associated with co-trimoxazole/colistin required discontinuation of medication in 11/27 treatment courses because of compliance problems, skin reactions or gastrointestinal intolerance. There were significantly fewer discontinuations in the ofloxacin (n = 2) and in the ciprofloxacin groups (n = 3). Major side effects of the quinolones included persistent icterus in one patient receiving ofloxacin and psychiatric symptoms in one patient receiving ciprofloxacin. It is concluded from these data that there were no statistically significant differences between the three treatment groups in respect of the prevention of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1987

Hypnotic action of pentobarbital in mice: a possible mechanism.

The effect of GABA receptor agonists (THIP and baclofen) on the hypnotic activity (loss of righting reflex and sleep time) of pentobarbital in mice was investigated. Combinations of either THIP-pentobarbital or baclofen-pentobarbital interacted synergistically by increasing hypnotic activity. The GABAa receptor antagonist, bicuculline, decreased the hypnotic effect of THIP-pentobarbital combinations but not that of baclofen-pentobarbital combinations. These results suggest that the hypnotic activity of pentobarbital involves GABAa receptor function.

Animals↗
PubMed1987

[Magnetic resonance tomography (MRT) of the orbit].

By using high field strengths and surface coils, MRT achieves a resolution comparable with CT in the orbita. The advantages of MRT are good contrast resolution and imaging in several planes. Twenty-six patients have been examined by MRT, which has shown high sensitivity and good detail for the demonstration of pathological changes. In spite of this, MRT at present is not a realistic alternative to ultrasound and CT, because it is unable to demonstrate bone and calcification; its specificity is low, but the time and cost of the examination is high. It is indicated only for problems involving the optic nerve and chiasma.

Adolescent↗
PubMed1985

Benzodiazepine receptors are not involved in the neurotoxicity and anti-electroshock activity of phenytoin in mice.

The present study was undertaken to investigate whether benzodiazepine receptors are involved in either the anticonvulsant activity of phenytoin against supramaximal seizures or maximal threshold seizures induced by electroshock or the neurotoxicity of phenytoin. Ro 15-1788, a benzodiazepine receptor antagonist, reversed the anticonvulsant activity of clonazepam against both supramaximal and maximal threshold seizures induced by electroshock but not that of phenytoin. Moreover, Ro 15-1788 did not decrease the neurotoxicity of phenytoin. These results suggest that benzodiazepine receptors are not involved in either the anticonvulsant action of phenytoin against seizures induced by electroshock or the neurotoxicity of phenytoin.

Animals↗
PubMed1985

gamma-Aminobutyric acid modulation of benzodiazepine receptor binding in vitro does not predict the pharmacologic activity of all benzodiazepine receptor ligands.

gamma-Aminobutyric acid (GABA) modulation of triazolam and nicotinamide binding to benzodiazepine (BDZ) receptors in vitro was compared with the neurotoxicity and anticonvulsant activity of these two drugs in vivo. GABA had no significant effect on the inhibitory potency of triazolam in [3H]flunitrazepam receptor binding, whereas GABA decreased the inhibitory potency of nicotinamide. When administered to mice, both triazolam and nicotinamide exhibited neurotoxicity by the rotorod test and anticonvulsant activity by the pentylenetetrazol seizure threshold test. This suggests that GABA modulation of the receptor binding of a BDZ ligand in vitro is not a reliable predictor of the pharmacologic activity of the ligand.

Animals↗
PubMed1985

Effect of GABA agonists on the neurotoxicity and anticonvulsant activity of benzodiazepines.

Progabide (50 mg/kg, i.p.), a GABA receptor agonist, significantly decreases the median minimal neurotoxic dose (TD50) of clobazam, chlordiazepoxide, and diazepam; the receptor binding of these substances is highly enhanced by muscimol. Progabide has no significant effect on the TD50 of clonazepam and triazolam; the receptor bindings of these substances is either only slightly enhanced or not altered by muscimol. Progabide also significantly decreases the median antimaximal electroshock dose (MES ED50) of all the benzodiazepines tested. However, progabide has no effect on the median antipentylenetetrazol dose (PTZ ED50) of the benzodiazepines. Likewise, THIP (2.5 mg/kg, i.p.) significantly decreases the TD50 of chlordiazepoxide but not that of triazolam. THIP significantly decreases the MES ED50 of chlordiazepoxide and triazolam but has no effect on the PTZ ED50 of these two substances. The above data suggest that benzodiazepine receptors linked to GABA receptors contribute to the minimal neurotoxicity and anti-MES activity but not to the anti-PTZ activity of benzodiazepines.

Animals↗
PubMed1985

Effect of picrotoxinin on benzodiazepine receptor binding.

The effect of picrotoxinin on [3H]flunitrazepam binding to benzodiazepine receptors was investigated. In mouse forebrain membranes, picrotoxinin inhibited basal, GABA- and pentobarbital-stimulated [3H]flunitrazepam binding; this inhibitory activity was temperature- and chloride ion-dependent. Scatchard analysis of the data indicates that picrotoxinin decreases the number of binding sites without altering binding affinity. In cerebellar membranes, picrotoxinin did not alter [3H]flunitrazepam receptor binding.

Animals↗
PubMed1985

gamma-Aminobutyric acid: temperature dependence in benzodiazepine receptor binding.

The effects of muscimol and/or incubation temperature on the inhibition of [3H]flunitrazepam receptor binding by benzodiazepine receptor ligands were investigated. At 0 degree C muscimol decreased the Ki values for some ligands as displacers of [3H]flunitrazepam binding to brain-specific sites while increasing or having no effect on the Ki values for other ligands. The Ki values for some ligands are higher at 37 degrees C than at 0 degree C but are reduced by muscimol at both 0 degrees and 37 degrees C. In contrast, the ligands whose Ki values are increased by muscimol either decreased or did not alter the Ki values at 37 degrees C as compared to those at 0 degree C. Incubation of membranes at 37 degrees C for 30 min accelerated gamma-aminobutyric acid (GABA) release by 221% over that at 0 degree C. These results indicate that changes in incubation temperature alter benzodiazepine receptor affinity for ligands via GABA.

Animals↗
PubMed1979

Opiate modification of intracranial self-stimulation in the rat.

Studies were conducted to confirm the involvement of central opiate receptors in the expression of opiate modulation of intracranial self-stimulation (ICSS). Biphasic, dose-related changes in ICSS responding are described following IP administration of morphine sulfate (1-25 mg/kg) and levorphanol tartrate (LEV, 0.5-5 mg/kg). Similar patterns of response modification are reported following intraventricular (IVt) administration of LEV (0.01-0.2 muMoles) LEV's enantiomorph, dextrorphan, was not found to elicit comparable effects after either IP or IVt administration. Both the facilitatory and the depressant phases of LEV's action were antagonized by naltrexone (10 microgram, IVt), which had no apparent effect on ICSS by itself. Complete tolerance developed to the suppression of responding by 2.5 mg/kg LEV (IP) but not to the facilitatory effect of 0.5 mg/kg (IP), during a 5-day course of administration. The implications of these results for opiate reinforcement theory are discussed and possible mechanisms are advanced.

Animals↗
PubMed1977

The ultrastructure of lymphadenosis benigna cutis (pseudolymphoma cutis).

In an ultrastructural study supplementing previous histological, cytochemical and immunocytological investigations of lymphadenosis benigna cutis, the tumor is shown to consist mainly of two cell types: Lymphocytes and macrophagocytic (reticulum?) cells. The tendency to spontaneous regression is manifested on the ultrastructural level by pronounced degenerative alterations.

Diagnosis, Differential↗
PubMedDate not supplied

Anticonvulsant profiles of the potent and orally active GABA uptake inhibitors SK&F 89976-A and SK&F 100330-A and four prototype antiepileptic drugs in mice and rats.

The anticonvulsant profiles of two potent and orally active gamma-aminobutyric acid (GABA) uptake inhibitors, 1-(4,4-diphenyl-3-butenyl)-3-piperidine-carboxylic acid hydrochloride (SK&F 89976-A) and 1-(4,4-diphenyl-3-butenyl)-1,2,5,6-tetrahydro-3-pyridine-carboxylic acid hydrochloride (SK&F 100330-A), were determined with a battery of well-standardized tests in mice and rats and compared with the profiles of phenytoin (PHT), carbamazepine (CBZ), valproate (VPA) and clonazepam (CZP) when subjected to the same tests. ED50 values were calculated and compared with TD50 values for minimal motor impairment to provide protective indexes (PI = TD50/ED50). The anticonvulsant profiles of SK&F 89976-A and SK&F 100330-A were similar and suggest that these compounds raise the threshold for seizure initiation rather than inhibit seizure spread. Like intraperitoneal (i.p.) PHT, CBZ, VPA, and CZP, SK&F 89976-A and SK&F 100330-A inhibited seizures in corneally kindled rats. The profiles of SK&F 89976-A and SK&F 100330-A were most similar to that of CZP and virtually opposite to that of PHT. Intraperitoneal SK&F 100330-A provided complete protection against pentylenetetrazol-induced seizures [subcutaneous (s.c.) PTZ] in mice but was ineffective against seizures induced by maximal electroshock (MES) at doses slightly greater than its TD50. SK&F 100330-A provided complete protection against picrotoxin-induced seizures (s.c. Pic) and against both clonus and forelimb tonic extension induced by NMDA N-methyl-D-aspartate [intracerebral ventricular (i.c.v.)-NMDA] in mice; however, SK&F 100330-A was ineffective against seizures induced by bicuculline (s.c. Bic) and strychnine (s.c. Strych) at doses slightly greater than its TD50. SK&F 89976-A was similar but provided partial protection against NMDA-induced clonus.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗