Comparative clinical trial of bemetizide/triamterene and cyclopenthiazide/potassium chloride combinations in patients with mild to moderate hypertension

A double-blind trial was carried out to compare the combination of 25 mg bemetizide plus 50 mg triamterene ('Hypertane') and 0.25 mg cyclopenthiazide plus 600 mg potassium chloride ('Navidrex' K) in the treatment of mild to moderate essential hypertension. Two well matched groups of patients were treated for periods of 6 weeks with one or other of the drugs under test. There were 2-week placebo run-in and run-out periods. Blood pressure and laboratory investigations were performed every 2 weeks during the trial period. Both treatments resulted in similar overall statistically significant reductions in blood pressure during the trial. With bemetizide/triamterene, mean lying blood pressure decreased by 11.1/11.2 mmHg and mean standing blood pressure by 15.9/10.3 mmHg; with cyclopenthiazide/potassium chloride the corresponding reductions were 14.9/12.1 mmHg and 9.1/11.7 mmHg. The fact that some of the observed overall reduction seen with both drugs was due to 'placebo effect' is discussed but the clinical importance of overall changes is stressed. There were no significant differences between changes in blood pressure with the two treatments. Biochemical changes were those expected with thiazide diuretics. However, the decrease in potassium and increases in urea and uric acid levels were less with bemetizide/triamterene than with cyclopenthiazide/potassium chloride. Clinical tolerance of both treatments was good.

The discrepancy between the cross-reactivity of a monoclonal antibody to serotonin and its immunohistochemical specificity

The rat monoclonal antibody YC5/45 has been shown to react specifically with serotonin containing neurones, and does not detect dopamine containing sites. On the other hand the monoclonal antibody recognizes dopamine, since it is capable of inhibiting the binding of 3H-YC5/45 to sheep red blood cells coated with serotonin albumin conjugate, or the direct agglutination of the same cells by the monoclonal antibody. Tryptamine and 5-methoxytryptamine are even better inhibitors, while derivatives with a modified-CH2-CH2-NH2 group are inactive. Treatment of the active compounds with paraformaldehyde increases their efficiency dramatically. The binding of antibody was also tested by cross linking with paraformaldehyde: dopamine, serotonin, tryptamine, 5-methoxytryptamine etc., to serum albumin. Only the serotonin derivative was active. The result shows that the discrimination specificity observed in immunohistochemistry is due to the paraformaldehyde fixation. It is concluded that for histochemical detection of serotonin by YC5/45, two reactive sites are necessary. The -CH2-CH2-NH2 group is probably modified by formaldehyde to produce a cyclic derivative to form the antibody recognition site. A different formaldehyde reactive site is required for cross linking to the tissue and this is provided by the presence of the 5-OH of serotonin which is absent in the others.

Rat monoclonal antitubulin antibodies derived by using a new nonsecreting rat cell line

Hybrid myeloma cell lines secreting monoclonal antibodies to tubulin have been prepared using rat myelomas and spleen cells from rats immunized with yeast tubulin. A comparison between the results obtained with the rat myeloma Y3-Ag 1.2.3., which secretes a light chain, and a new line, YB2/O, which does not, shows that they are both excellent parental lines and that the second produces hybrids with no myeloma chain components. The antitubulin antibodies in the serum of rats bearing two of the hybrid myeloma tumors gave titers of up to 1:10(6) from which large amounts of monoclonal antibodies could be easily purified. They recognized tubulin from yeast as well as from birds and mammals. The two antibodies gave clear immunofluorescent staining of yeast mitotic spindles as well as the interphase microtubule network of tissue culture cells. Some difference in the pattern of immunofluorescence staining of yeast cells and nuclei was observed between the two antibodies. The purified antibodies could be conjugated to colloidal gold particles and used for direct labeling of yeast microtubules for electron microscopy.

Synthesis of N7-hydroxyethylguanine and O6-hydroxyethylguanine. Markers for the reaction of ethylene oxide (EO) with DNA

O6-Hydroxyethylguanine has been synthesized by reaction of mono-sodium glycolate with 6-chloroguanine. The crystalline product has been characterized using a variety of analytical techniques and compared with a sample of the corresponding N7-hydroxyethyl derivative. These 2 chemicals may prove useful as standards when studying the reaction of ethylene oxide (EO) with DNA.

Immunocytochemical detection of serotonin with monoclonal antibodies

The development of the monoclonal antibody YC5/45 HLK (YC5/HLK) against a 5HT-bovine seroalbumin immunogen and its application for immunocytochemistry is described. The YC5/HLK antibody is the product of a rat x rat hybrid myeloma, producing a heavy chain and two light chains. In hemagglutination tests, the antibody cross-reacts to entirety with dopamine, serotonin, and tryptamine at high concentrations. The serotonin-albumin conjugate is 20,000 times more effective in displacing the binding antibody, while albumin itself goes unrecognized by the antibody. In fixed preparations of brain tissue, immunofluorescence is observed only in neurons known to contain serotonin, while no reaction is observed in dopamine-rich neurons. All immunofluorescence is extinguished by the use of agents that inhibit the biosynthesis of 5HT, but not of the catecholamines.

A monoclonal antibody to the HLA-DR product recognizes a polymorphic Ia determinant in mice

A rat monoclonal antibody which recognizes a product of the HLA-DR locus is described. The determinant recognized by this antibody is monomorphic in man but polymorphic in mice. Mapping studies with inbred and recombinant strains of mice show that this antigen as associated with H-2 haplotypes b, d and q and is coded for by genes within the I-A subregion.

Isolation of six monoclonal alloantibodies against rat histocompatibility antigens: clonal competition

We describe the isolation of six clones and some variant derivatives of rat x mouse hybrid myelomas secreting alloantibody against antigens of the rat major histocompatibility complex. Very large numbers of active hybrids were obtained but many were lost early in the post-fusion period; evidence is presented for rapid selective processes operating in uncloned complex hybrid cultures. The results suggest that the secretion of specific immunoglobulin chains is as stable a function in rat x mouse hybrid myelomas as in mouse x mouse hybrid myelomas.

Diastematomyelia in a geriatric patient

The discovery of diastematomyelia in a geriatric patient is a rare occurrence. A 76-year-old woman with this entity was not diagnosed until she developed superimposed motor neuron disease.

Avian cholera in waterfowl in Saskatchewan, spring 1977

Avian cholera was diagnosed in lesser snow geese (Anser c. caerulescens), Ross' geese (Anser rossii) and individuals of several other waterfowl species in a small area of south-western Saskatchewan over a 1 month period during the 1977 spring migration. Approximately 250 dead birds were found. This is apparently the first time avian cholera has been reported in migrating waterfowl in Canada. The site of the mortality was midway between the wintering and nesting areas of the two principal species, and the significance of the occurrence of the disease this far north is discussed.

The effect of positive end-expiratory pressure (PEEP) ventilation in neurogenic pulmonary oedema. Report of a case

The effect of positive end-expired pressure ventilation (PEEP) on mean systemic arterial pressure, mean pulmonary arterial pressure, mean pulmonary wedge pressure, mean intracranial pressure (ICP), and cerebral perfusion pressure (CPP), in a case of neurogenic pulmonary oedema (NPO) is presented. PEEP improved oxygenation, reduced, and finally stopped clinical pulmonary oedema. In this patient PEEP produced severe systemic hypotension. As a consequence of this, CPP was impaired.