Lorazepam and diazepam as adjuncts to epidural anaesthesia for caesarean section.

Lorazepam 0.05 mg X kg-1 and diazepam 0.1 mg X kg-1 administered intravenously were compared as sedatives for 42 patients undergoing Caesarean Section under epidural anaesthesia.

The effect of foetal acidosis on bupivacaine levels in utero.

Amide local anaesthetics are weak bases with pK's of 7.80 or greater. Therefore, tissue acidosis may result in ionization and "trapping" of the basic local anaesthetics The following study was done in the pregnant ewe to determine if the highly protein-bound local anaesthetic bupivacaine demonstrates ion-trapping in the acidotic foetus.

Fate of neurohypophysial granule membranes after secretion in the rat: generation of a new apparent organelle by freezing and thawing secretory granules.

The contents and membranes of the secretory granules in the rat neurohypophysis were labelled in vivo with [35S]cysteine and [3H]choline respectively. Density-gradient centrifugation of the labelled granules showed the membrane label to be distributed largely between two peaks: one associated with intact granules and one with the characteristics of empty granule envelopes. Stimulation of hormones release in vitro led to the movement of membrane label from the intact granule fraction to the other one, consistent with the recapture of membrane as large vesicles.

Effects of small doses of colchicine on the components of the hypothalamo-neurohypophysial system of the rat.

Small doses (3.5 micrograms and 7 micrograms) of colchicine injected intracisternally caused an interruption of transport of secretory material from the supraoptic and paraventricular nuclei of the hypothalamus to the neural lobe of the pituitary gland. Transport was assessed by direct measurement of the incorporation of [35S] cysteine into neurophysins, by radioimmunoassay of accumulated material in discrete areas of the system and by immunocytochemistry.

Effects of tunicamycin on the hypothalamo-neurohypophysial system of the rat.

Intracisternal injections of tunicamycin, an inhibitor of glycosylation, decreased the incorporation of [35S]cysteine into the neurophysins in the rat neurohypophysis. Histochemical and immunocytochemical studies showed that there was no concomitant decrease in the amount of secretory product in the perikarya of the hypothalamo-neurohypophysial neurones. Indeed there was an increase, although this was not associated with neurosecretory granules as judged electron-microscopically.

Cimetidine premedication in elective caesarean section.

A single intramuscular injection of Cimetidine was compared to oral antacid premedication in 17 patients undergoing elective Caesarean section. Seven patients in the Cimetidine group and four in the antacid group had gastric volumes in excess of 50 ml after induction of anaesthesia, while two patients in each group had gastric pH less than 2.5 after induction.

Preparation of antisera to three individual rat neurophysins and their use for radioimmunoassays.

A number of antisera have been raised against individual rat neurophysins. One of these proved suitable for the specific radioimmunoassay of rat vasopressin-neurophysin and data validating such a use are presented. Use of this antiserum showed that vasopressin-neurophysin is present in rat neurohypophyses in equimolar amounts to vasopressin, while in the hypothalamus the assay detected twice as much neurophysin-like material as hormone.

Distribution of granulopoietic activity in the human skeleton, studied by colony growth in agar diffusion chambers.

The colony forming ability of bone marrow cells from 110 haematologically normal patients was investigated by their growth in semi-solid agar in intraperitoneal diffusion chambers. Marrow aspirated from the sternum showed a consistently higher colony yield than that from the iliac crest. Study of site variation in the individual was possible in donors for bone marrow transplantation.

Incorporation of radioactive precursors into the membrane and contents of the neurosecretory granules of the rat neurohypophysis as a method of studying their fate.

Rat neural lobes have been separated into subcellular fractions by differential centrifugation at various times after an intracisternal injection of [35S]cysteine or [3H]choline. Both isotopes led to a rise and fall in the radioactivity of neurosecretory granules (NSG) which paralleled that found previously for the neurohypophysial hormones and the neurophysins. While the radioactivity of the NSGs resulting from [35S]cysteine injection was predominantly associated with granular contents, [3H]choline injections led to a preferential labelling of the granular membrane.

Assessment of bone marrow function: microscopy versus the agar colony assay.

Changes in bone marrow status followig cytotoxic chemotherapy were measured by means of peripheral blood counts, bone marrow cytology and colony-formation in agar culture. A correlation is described between colony-forming ability and marrow differential count.

Movement of neurosecretory product through the anatomical compartments of the neural lobe of the pituitary gland. An electron microscopic autoradiographic study.

Electron-microscope autoradiographs have been prepared from the neural lobes of the pituitary glands of rats which had received intracisternal injections of [35S] cysteine at various times before gland removal. The rate of appearance and disappearance of autoradiographically demonstrable radioactivity in the neural lobe closely paralleled that previously determined, biochemically, for radioactive hormones and neurophysins. Radioactivity was appreciably associated with the undilated parts of neurosecretory axons only during the first few hours after injection of the label.