Biomedical subjects

J J Driessen

Publications and source records attributed to J J Driessen.

45 records · Page 3Linked to original sources

PubMed1984

Effect of some benzodiazepines on peripheral neuromuscular function in the rat in-vitro hemidiaphragm preparation.

The effect of equimolar cumulative concentrations of 11 different benzodiazepines on the indirectly evoked twitch contraction was investigated in the rat in-vitro phrenic nerve-hemidiaphragm preparation. Depending on the pattern of the concentration-response curves two groups of benzodiazepines can be distinguished: (i) a first group with a biphasic action, e.g. potentiation of twitch tension in low concentrations and depression of twitch tension in high concentrations, and (ii) a second group with primary depression of twitch tension with increasing concentrations. All of the tested compounds ultimately caused a 100% depression of twitch tension at concentrations ranging from 0.175 to 0.35 mmol litre-1. Although this peripheral effect of benzodiazepines on neuromuscular function is not the main site of action of these compounds, there are enough arguments to state that it is not a simple toxic effect. There is some evidence from this study that the peripheral component of the benzodiazepine effect on muscle relaxation may involve a multi- rather than one single receptor system.

Animals↗

PubMed1984

Epidural anesthesia with plain bupivacaine 0.75% for elective caesarean section.

The clinical effects of epidural anesthesia with bupivacaine 0.75% for elective caesarean section were investigated in 20 healthy pregnant women. The mean total dose of bupivacaine which offers sufficient sensory and motor block, provided the epidural catheter is properly placed, was 137.5 mg. Maternal hypotension occurred in 4 patients in spite of prehydratation and left uterine displacement. No maternal systemic toxicity or local neurotoxicity was found. The results of the Apgar scoring and the neonatal acid-base studies showed that there is no clinically important neonatal depression with this technique.

Adult↗

PubMed1983

Quantitative determination of specified chlorobiphenyls in fish with capillary gas chromatography and its use for monitoring and tolerance purposes.

A gel permeation (GPC) clean-up procedure of fish samples in combination with capillary gas chromatography is used for the determination of individual chlorobiphenyls. The described method is compared with a more universal method based on saponification. Starting from a tolerance for PCB's expressed as a technical Aroclor, tolerance for some specified individual chlorobiphenyls are derived. It is shown that these tolerances for specified individual chlorobiphenyls can be used for monitoring and tolerance purposes. Rejection obtained with the Dutch PCB tolerance agree with rejections obtained with individual tolerances.

Animals↗

PubMed1983

Clinical effects of regional intravenous guanethidine (Ismelin) in reflex sympathetic dystrophy.

Twenty patients with documented reflex sympathetic dystrophy were treated with a series of regional intravenous guanethidine blocks. The mean delay between the first clinical symptoms and the start of guanethidine blocks was 3.6 months. The overall result was good in 11 patients, moderate in two patients and poor in seven patients. Poor results are due mainly to incorrect diagnosis and to application either too late in the third phase or too early in the first phase when only signs of increased blood flow are part of the symptomatology. Side effects, except pain after the injection, were few and of minor importance. The tolerance of the procedure may be improved by preceding the injection of guanethidine by an injection of a local anaesthetic agent. It may be concluded that with correct diagnosis and indication, guanethidine injections may play an important part in the treatment of reflex sympathetic dystrophy and may replace sympathetic blocks with local anaesthetics because of the longer duration of action and lower incidence of serious side-effects.

Adult↗

PubMed1983

[Comparative study of thiopental and midazolam for induction of anesthesia].

In 40 female ASA class I-II patients, scheduled for laparoscopy, midazolam 0.2 mg kg-1 i.v. was compared with thiopentone 5 mg kg-1 i.v. for induction of anaesthesia after parenteral premedication. Loss of the eyelash reflex occurred significantly earlier (p less than 0.005) in the thiopentone group (23.3 s) than in the midazolam group (37.5 s). During orotracheal intubation a more stable cardiovascular course was found with midazolam than with thiopentone. Awakening was markedly slower with midazolam than with thiopentone. Anterograde amnesia of more than 60 minutes after induction of anaesthesia occurred in 50% of midazolam patients compared with 10% in the thiopentone group. No significant differences in side effects could be found. Midazolam 0.2 mg kg-1 was sufficient to induce anaesthesia reliably after premedication with droperidol and fentanyl shortly before induction.

Adult↗

PubMed1982

Comparison of diazepam and midazolam as oral premedicants for bronchoscopy under local anesthesia.

A randomized double blind comparison between diazepam 10 mg, and midazolam 15 mg as oral premedicants in diagnostic fiber optic bronchoscopy under local anesthesia was made. The subjective assessments by the patient, the observer and the bronchoscopist showed that midazolam 15 mg orally gives an at least comparable degree of sedation, relief of anxiety and patient's tolerance as diazepam 10 mg orally. Midazolam 15 mg gives some degree of anterograde amnesia where diazepam 10 mg completely fails. Psychomotor recovery after 4 hours is better after midazolam 15 mg than after diazepam 10 mg. No adverse reactions were seen with both premedicants.

Amnesia↗

PubMed1981

Simultaneous determination and pharmacokinetics of midazolam and its hydroxymetabolites in plasma and urine of man and dog by means of high-performance liquid chromatography.

A HPLC (high performance liquid chromatography) method for the determination of 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1,4]benzodiazepine (midazolam, Ro 21-3981, Dormicum) and its hydroxy metabolites has been developed. The half-life of elimination of midazolam and the glucuronides of the metabolites 1-hydroxymethyl-midazolam, 4-hydroxy-midazolam and 1-hydroxymethyl-4-hydroxy-midazolam are identical, 53 min in dogs and 90 min in man.

Aged↗

PubMed1981

Midazolam as a sedative on regional anesthesia. Preliminary results.

Diazepam is widely used as a sedative for loco-regional anesthesia. The venous irritation and long duration of action and hangover may be a drawback. We compared 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1,4]benzodiazepine (midazolam, Ro 21-3981, Dormicum), a new water-soluble benzodiazepine, with diazepam for cardio-respiratory changes, onset time, duration of action, amnesia and venous irritation after a single i.v. shot in loco-regional anesthesia.

Anesthesia, Conduction↗

PubMedDate not supplied

Pharmacokinetics of diazepam and four 3-hydroxy-benzodiazepines in the cat.

Biotransformation and elimination of diazepam and four 3-hydroxy-benzodiazepines after i.v. injection in anaesthetized cats were investigated. Decay of plasma concentration of 3-hydroxy-benzodiazepines was slow and plasma concentrations of their glucuronides were lower than of unchanged parent compounds. In the urine, very low excretion rates of all investigated benzodiazepines were found during the first eight hours. It is concluded that cats poorly glucuronidate 3-dydroxy-benzodiazepines.

Animals↗