Simplifying assessment of dimensions of oral lesions using a syringe and 'impression planimetry' with printer paper

Two novel methods of measuring the dimensions of oral lesions are described, which would be of help in deciding relative efficacies of different therapeutic agents when used in clinical trials after larger studies quantitatively assessed for inter/intraobserver variability.

Head and neck cancers: results of thermoradiotherapy versus radiotherapy

Sixty-five patients were included in a randomized clinical study to evaluate the efficacy of local hyperthermia as a concomitant agent to radiotherapy in the treatment of carcinoma of the head and neck region. Local hyperthermia at 42-43 degrees C was generated by a 27 x 12 MHz radiofrequency diathermy unit and was used before radiotherapy in 33 patients; the remaining 32 patients were subjected to radiotherapy alone. The response in patients with early lesions (Stage I and II) was similar for both the groups, while in patients with advanced disease (Stage III and IV) a significantly better tumour control was obtained by the use of the combined treatment.

Histamine H2-receptor mediated stimulation of gastric acid secretion by mercaptomethylimidazole

Intraperitoneal administration of mercaptomethylimidazole (methimazole), a potent antithyroid drug belonging to the thionamide group, caused a significant increase in gastric secretion both in control and pylorus-ligated mice. The drug also induced significant stimulation of gastric acid and pepsinogen secretion in both the animal systems studied. The dose-response curve indicated a nearly 10-fold increase in acid output by injection of 0.55 mg mercaptomethylimidazole per 25 g body weight. The duration profile of the drug response at the dose mentioned showed acid secretion almost at a linear rate up to 2.5 hr, after which the response decreased to some extent. Of the other antithyroid drugs of the same family, only thiourea activated acid secretion but the response was much smaller than mercaptomethylimidazole. Histamine, one of the physiological secretagogues of gastric acid secretion, was found to be less active than mercaptomethylimidazole. Mercaptomethylimidazole-induced stimulation of acid secretion could be effectively blocked by prior administration of cimetidine and completely by omeprazole and not by atropine. Verapamil and nifedipine had also some inhibitory effect. These observations indicate that mercaptomethylimidazole stimulates HCl secretion through the involvement of H2-receptor and through the functioning of the H+-K+-ATPase of the parietal cells. The bulk movement of water during increased HCl secretion was partially sensitive to cimetidine and omeprazole and was also associated with an increased secretion of Na+ and K+ in the gastric juice. This indicates that mercaptomethylimidazole also induced water transport through a separate mechanism.

Horseradish peroxidase-catalyzed conversion of iodine to iodide in presence of EDTA and H2O2

EDTA (4 mM) blocks the oxidation of iodide to I-3 (increase of extinction at 353 nm) by H2O2 catalyzed by horseradish peroxidase, which is reversed by the addition of an equimolar concentration of Zn2+. Addition of suboptimal concentration of EDTA (2 mM) not only decreases the rate of forward reaction of I-3 formation but also causes loss of extinction of the same when I-3 is generated. The loss of extinction of I-3 is proportional to the enzyme concentration and is blocked by azide, the inhibitor of the peroxidase. EDTA also causes bleaching of nonenzymatically formed I-3 (from iodide and H2O2) only in the presence of horseradish peroxidase, and the effect is reversed by the equimolar concentration of Zn2+. Both the bleaching of I-3 by EDTA and reversal of EDTA effect by Zn2+ are sensitive to azide. The decrease of extinction of I-3 (formed by dissolving iodine in KI solution) is dependent on EDTA, H2O2, and horseradish peroxidase. Molecular iodine is also bleached but at a slower rate than I-3. Evidence is presented to show that this bleaching of I-3 is due to enzymatic conversion of I-3 to iodide in presence of EDTA and H2O2 and this involves pseudocatalatic degradation of H2O2 to O2.

Endocrine control of extrathyroidal peroxidases and iodide metabolism

The role of the thyroid and adrenal glands on iodide transport and peroxidase-catalyzed formation of iodotyrosines in extrathyroidal tissues such as stomach and submaxillary glands has been investigated. Thyroidectomy stimulates iodide concentration and iodotyrosine formation in stomach, sensitive to the administration of thyroxine but having no effect on the peroxidase activity. In contrast, although thyroidectomy stimulates the submaxillary peroxidase which is reversed on treatment with thyroxine, it has no effect on iodide concentration and organification in the submaxillary gland. Gastric peroxidase activity is specifically stimulated by adrenalectomy and is inhibited by glucocorticoids which also inhibit iodotyrosine formation in stomach.

Peroxidase-catalysed iodotyrosine formation in dispersed cells of mouse extrathyroidal tissues

A method has been developed for the isolation of cells, high in iodine uptake and peroxidase activity, from the stomach and submaxillary gland of mice. The isolated cells could produce protein-bound monoiodotyrosine, di-iodotyrosine and an unknown iodocompound. The reactions were catalysed by peroxidase and were sensitive to antithyroid drugs and haemoprotein inhibitors but were insensitive to TSH. In-vitro iodination of stomach or submaxillary soluble proteins with the respective peroxidase yielded similar iodocompounds while thyroxine was produced when thyroglobulin was used instead.

Cyclic AMP induces synthesis of prostaglandin E1 in platelets

Although platelets are known to synthesize small amounts of prostaglandin E1 the control of the formation of this prostanoid has not been investigated. Incubation of human platelet-rich plasma with various compounds which are known to increase cyclic AMP concentration in platelets and inhibit platelet aggregation also increased intracellular prostaglandin E1 synthesis. The prostaglandin E1 was isolated by high pressure liquid chromatography and definitively identified by negative and positive ionization mass spectroscopy. The amounts of prostaglandin E1 formed were proportional to the concentration of cyclic AMP in platelets. Prostacyclin (10 nM) which is the most potent stimulator of cyclic AMP formation increased intracellular cyclic AMP by 4.6 fold and prostaglandin E1 level by 3 fold over the basal levels. Addition of theophylline, a cyclic AMP phosphodiesterase inhibitor, together with prostacyclin increased cyclic AMP concentration 8.7-fold and prostaglandin E1 level 12-fold compared to basal concentrations. Dibutyryl cyclic AMP (2 mM) and 8-bromo cyclic AMP (0.1 mM) increased prostaglandin E1 levels by 3 fold and 2 fold over the basal level, respectively. Prostaglandin D2 (3 microM) when added to platelet-rich plasma increased the cyclic nucleotide levels by 2 fold concomitant with 2 fold increase in prostaglandin E1 concentration. In contrast prostaglandin E2 or prostaglandin F2 alpha which had no effect on cyclic AMP level did not affect the prostaglandin E1 synthesis. Addition of 2',5'-dideoxyadenosine, an inhibitor of adenylate cyclase, to platelet-rich plasma inhibited both the increase of intracellular prostaglandin E1 and cyclic AMP levels induced by prostacyclin.

Synthesis of 3 alpha,7 alpha,12 alpha,25-tetrahydroxy-5 beta-cholestan-24-one, an intermediate in the 25-hydroxylation pathway of cholic acid biosynthesis from cholesterol

This paper describes the chemical synthesis of 3 alpha,7 alpha,12 alpha,25-tetrahydroxy-5 beta-cholestan-24-one via selective oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha, 24 xi,25-pentol with silver carbonate on celite. The structure of this 24-keto bile alcohol was confirmed by gas-liquid chromatography and mass spectrometry. Synthesis of this compound via pyridinium chlorochromate oxidation of the triacetoxy derivative of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24 xi,25-pentol followed by saponification further established its structure. 3 alpha,7 alpha,12 alpha,25-Tetrahydroxy-5 beta-cholestan-24-one was required for the in vivo and in vitro studies of side-chain oxidation and cleavage in the 25-hydroxylation pathway of cholic acid biosynthesis.

Lipid alterations in acute pancreatitis

The authors studied the lipid profile in acute pancreatitis in humans and also in dogs in which this disease had been induced experimentally. Blood samples were analysed by mass spectroscopy and gas chromatography. During the acute phase of the pancreatitis there was a significant reversal of the ratio of unsaturated fatty acids. There was a marked increase in the concentration of fatty acids in the blood with monounsaturation in both carbon-16 and carbon-18 chains and diunsaturation in the later carbon chains. These changes have not been reported in any disease state.

Permeability and enterotoxic factors of nonagglutinable vibrios Vibrio alcaligenes and Vibrio parahaemolyticus

Enterotoxic factor (EF) was present and could be developed in nonagglutinable vibrios, but not the permeability factor (PF). Presence of PF without EF in Vibrio parahaemolyticus is significant. Both EF and PF were absent in V. alcaligenes.