Effect of uremia on rates of ethanol disappearance from the blood and on the activities of the ethanol-oxidizing enzymes.

The effect of uremia on ethanol metabolism was investigated. Uremia was induced in male Spraque-Dawley rats by removal of approximately 85 per cent of the renal mass. Control animals had a sham operation. The mean activity of alcohol dehydrogenase was markedly increased in the uremic rats to 2.12 +/- 0.13 (S.E.M.) mumoles per milligram of protein per hours as compared with a control value of 1.39 +/- 0.13 mumoles per milligram of protein per hour (p less than 0.001). There were no changes in the activity of the microsomal ethanol oxidizing system, in catalase activity present in the microsomes, or in the rates of ethanol disappearance from the blood. Uremia resulted in decreases in microsomal cytochrome -450, but no changes in cytochrome b5, NADPH-cytochrome c reductase, or in the activities of aniline hydroxylase and aminopyrine demethylase. The increase in alcohol dehydrogenase activity could not be reproduced by incubation of liver from a normal rat with uremic rat plasma, uremic human serum, or urea. Also, the increase in the enzyme activity was not associated with changes in leucocyte ascorbic acid levels. The cause and physiologic significance of the increase in alcohol dehydrogenase activity in uremia remain to be elucidated.     

Reduced beta-adrenoceptor sensitivity in the elderly.

The effect of age on sensitivity to both isoproterenol and propranolol has been investigated in 27 male volunteers aged 21 to 73 yr. The dose of isoproterenol (given as a rapid intravenous injection) required to increase the resting heart rate by 25 bpm (I25) increased with age. The I25 was repeated during an intravenous infusion of propranolol and the dose ratio (I25 after propranolol divided by the control I25) determined. This was related to the concentration of free propranolol in plasma. It was found that the effectiveness of any given free concentration diminished progressively with age. These data are consistent with a diminished responsiveness of the beta-adrenoceptor to both agonist and antagonist drugs with advancing years.     

Effects of cyclopentyladenosine on isoproterenol response in adult and senescent cardiac tissue from Fischer 344 rats

To characterize age-related changes in beta-adrenergic responsiveness and to test the hypothesis that an increase in the effects of adenosine contribute to impaired beta-adrenergic responsiveness, Fischer 344 rat right atria (RA), left atria (LA), and left ventricular trabeculae carnae were exposed to the beta-receptor agonist isoproterenol (ISO), followed by four doses of the selective adenosine A(1) receptor agonist cyclopentyladenosine (CPA). Spontaneous contractile rates of adult RA were inhibited more than senescent RA by CPA. Contractility (+dF/dt) of adult LA was reduced more than senescent LA by CPA. Left trabeculae carnae tissue responded weakly to CPA, but senescent tissue was less responsive than adult tissue. Senescent atrial A(1) receptor density was 56% greater than in adult tissue, whereas the density in senescent ventricles was 39% lower than in adult tissue. No significant difference in antagonist affinities (K(d)) of A(1) receptor was observed between adult and senescent atria. In addition, agonist competition curves indicated a significant increase in senescent atrial and a decrease in senescent ventricular tissue in the affinity of agonist for high-affinity A(1) receptors with no difference in dissociation constant (K(i)). No significant age-related differences in atrial or ventricular tissues occurred in either the antagonist affinity (K(d)) or density (B(max)) of the beta-adrenergic receptors. CPA was found to inhibit ISO-stimulated adenylate cyclase activity more in senescent than in adult atrial and ventricular membrane preparations. We conclude that age-related differences in functional response to ISO and CPA, A(1) receptor density, and ISO-stimulated adenylate cyclase activity differ in atrial and ventricular myocardium.     

Comparison of mechanical and electrical activity and interstitial cells of Cajal in urinary bladders from wild-type and W/Wv mice

Background and purpose:

W/W^v and wild-type murine bladders were studied to determine whether the W/W^v phenotype, which causes a reduction in, but not abolition of, tyrosine kinase activity, is a useful tool to study the function of bladder interstitial cells of Cajal (ICC).

Experimental approach:

Immunohistochemistry, tension recordings and microelectrode recordings of membrane potential were performed on wild-type and mutant bladders.

Key results:

Wild-type and W/W^v detrusors contained c-Kit- and vimentin-immunopositive cells in comparable quantities, distribution and morphology. Electrical field stimulation evoked tetrodotoxin-sensitive contractions in wild-type and W/W^v detrusor strips. Atropine reduced wild-type responses by 50% whereas a 25% reduction occurred in W/W^v strips. The atropine-insensitive component was blocked by pyridoxal-5-phosphate-6-azophenyl-2′,4′-disulphonic acid in both tissue types. Wild-type and W/W^v detrusors had similar resting membrane potentials of −48 mV. Spontaneous electrical activity in both tissue types comprised action potentials and unitary potentials. Action potentials were nifedipine-sensitive whereas unitary potentials were not. Excitatory junction potentials were evoked by single pulses in both tissues. These were reduced by atropine in wild-type tissues but not in W/W^v preparations. The atropine-insensitive component was abolished by pyridoxal-5-phosphate-6-azophenyl-2′,4′-disulphonic acid in both preparations.

Conclusions and implications:

Bladders from W/W^v mice contain c-Kit- and vimentin-immunopositive ICC. There are similarities in the electrical and contractile properties of W/W^v and wild-type detrusors. However, significant differences were found in the pharmacology of the responses to neurogenic stimulation with an apparent up-regulation of the purinergic component. These findings indicate that the W/W^v strain may not be the best model to study ICC function in the bladder.     

Clarification of glycosylphosphatidylinositol anchorage of OTOANCORIN and human OTOA variants associated with deafness

Otoancorin (OTOA), encoded by OTOA, is required for the development of the tectorial membrane in the inner ear. Mutations in this gene cause nonsyndromic hearing loss (DFNB22). The molecular mechanisms underlying most DFNB22 remain poorly understood. Disruption of glycosylphosphatidylinositol (GPI) anchorage has been assumed to be the pathophysiology mandating experimental validation. From a Korean deaf family, we identified two trans OTOA variants (c.1320 + 5 G>C and p.Gln589ArgfsX55 [NM_144672.3]) . The pathogenic potential of c.1320 + 5 G>C was confirmed by a minigene splicing assay. To experimentally determine the GPI anchorage, wild‐type (WT) and mutant OTOA harboring p.Gln589ArgfsX55 were expressed in HEK293T cells. The mutant OTOA with p.Gln589ArgfsX55 resulted in an uncontrolled release of OTOA into the medium in contrast with phosphatidylinositol‐specific phospholipase C‐induced controlled release of WT OTOA from the cell surface. Together, the results of this reverse translational study confirmed GPI‐anchorage of OTOA and showed that downstream sequences from the 589th amino acid are critical for GPI‐anchorage.     

Predictors of successful labor induction with oral or vaginal misoprostol

Objective: To identify independent predictors of successful labor induction with oral or vaginal misoprostol.

Methods: Women enrolled in four previous randomized trials involving oral or vaginal misoprostol for cervical ripening and labor induction were included in the present cohort study, with dosing of 25–50?μg every 4 to 6?h vaginally (n?=?574) or 50?μg every 4?h orally (n?=?207). Multiple logistic regression was performed to identify factors independently associated with successful labor induction – defined as vaginal delivery within 12?h, vaginal delivery within 24?h and spontaneous vaginal delivery. Predictors of Cesarean birth and the need for only one dose of misoprostol were also identified. Variables included in the models were maternal age, weight, height, parity, gravidity, membrane status, route of misoprostol, gestational age, birth weight, and Bishop score and its individual components.

Results: Maternal age, height, weight, parity, birth weight, dilatation, effacement and cervical station were associated with vaginal delivery within 24?h of induction. Maternal age, height, weight, nulliparity, birth weight and route of misoprostol were associated with Cesarean birth, with oral misoprostol being associated with a lower rate of Cesarean birth. The need for only one dose of misoprostol was predicted by maternal height, weight, parity, gestational age, Bishop score and route of misoprostol.

Conclusion: Characteristics of the woman (height, weight, parity), the fetus (birth weight) and some of the individual components of the Bishop score, were associated with successful labor induction, with oral misoprostol being associated with a lower rate of Cesarean birth.     

ROLE OF EPIDURAL MEDICATION IN LUMBOSCIATIC SYNDROME

Role of epidural medication through caudal route was studied in 109 patients having lumbago with or without sciatica to highlight the value of this mode of treatment which relieved symptoms in more than 70% of cases without hospitalisation and without being off work for long periods as in usual methods of conservative treatment.KEY WORDS: Epidural medication, Backache, Lumbago, Sciatica