High blood pressure. Causes, symptoms, treatments

Lipid-lowering effect and changes in estimated cardiovascular risk after switching to a tenofovir-containing regimen for the treatment of HIV-infected patients.

2017-05-06

We hypothesized that inhibition of carbonic anhydrase in the central nervous system by acetazolamide should limit the rise in cisternal cerebrospinal fluid (CSF) [HCO3-] observed in metabolic alkalosis. To test this hypothesis, isosmotic isonatremic metabolic alkalosis was produced in two groups of anesthetized, paralyzed, and mechanically ventilated dogs (8 in each group). Group II animals received 50 mg/kg of acetazolamide intravenously 1 h before induction of metabolic alkalosis of 5-h duration. Renal effects of acetazolamide were eliminated by ligation of renal pedicles. In both groups cisternal CSF [Na+] remained relatively constant during metabolic alkalosis. In group I CSF [Cl-] decreased 3.6 and 8.2 meq/l, respectively, 2.5 and 5 h after induction of metabolic alkalosis. Respective increments in CSF [HCO3-] were 3.4 and 6.0 meq/l. In acetazolamide-treated dogs, during metabolic alkalosis, increments in CSF [HCO3-] (4.8 and 7.2 meq/l, respectively, at 2.5 and 5 h) and decrements in CSF [Cl-] (9.1 and 13.3 meq/l) were greater than those observed in group I. We conclude that, in dogs with metabolic alkalosis and bilateral ligation of renal pedicles, acetazolamide impairs CSF regulation of HCO3- and Cl- ions; acetazolamide not only failed to impede HCO3- rise but actually appeared to increase it. The mechanisms for these observations are discussed.

The η-carbonic anhydrases (CAs, EC 4.2.1.1) were recently discovered as the sixth genetic class of this metalloenzyme superfamily, and are so far known only in protozoa, including various Plasmodium species, the causative agents of malaria. We report here an inhibition study of the η-CA from Plasmodium falciparum (PfCA) against a panel of sulfonamides and one sulfamate compound, some of which are clinically used. The strongest inhibitors identified were ethoxzolamide and sulthiame, with KIs of 131-132 nM, followed by acetazolamide, methazolamide and hydrochlorothiazide (KIs of 153-198 nM). Brinzolamide, topiramate, zonisamide, indisulam, valdecoxib and celecoxib also showed significant inhibitory action against PfCA, with KIs ranging from 217 to 308 nM. An interesting observation was that the more efficient PfCA inhibitors are representative of several scaffolds and chemical classes, including benzene sulfonamides, monocyclic/bicyclic heterocyclic sulfonamides and compounds with a more complex scaffold (i.e., the sugar sulfamate derivative, topiramate, and the coxibs, celecoxib and valdecoxib). A comprehensive inhibition study of small molecules for η-CAs is needed as a first step towards assessing PfCA as a druggable target. The present work identifies the first known η-CA inhibitors and provides a platform for the development of next generation novel PfCA inhibitors.

Argon laser peripheral iridoplasty significantly is more effective than conventional systemic medications in reducing IOP levels in acute PACG in eyes not suitable for immediate laser peripheral iridotomy within the first 2 hours from the initiation of treatment. Argon laser peripheral iridoplasty is a safe and more effective alternative to conventional systemic medications in the management of acute PACG not amenable to immediate laser peripheral iridotomy.

Cerebrovascular diseases are one of the most important complications of systemic lupus erythematosus (SLE). The diagnostic imaging of neuropsychiatric SLE complications presents many problems. This study was undertaken to investigate cerebral blood flow char s and its reactivity to hypercapnia by means of acetazolamide test in SLE patients.

STDU was available for evaluating postsurgical patency of the bypass flow and the rCBF of the ipsilateral MCA territory. The mean blood flow velocity of the operated STA is a highly sensitive parameter for predicting rCBF in the ipsilateral MCA territory after EC-IC bypass.

Studies were performed to determine the mechanism by which short-chain fatty acids increase colonic Na and Cl absorption by determining unidirectional 22Na and 36Cl fluxes across isolated stripped mucosa from the rat distal colon under voltage clamp conditions. Mucosal butyrate (25 mM, in the absence of bicarbonate) significantly enhanced both net Na and net Cl absorption by 7.0 +/- 1.3 and 6.9 +/- 1.0 microEq/h.cm2, respectively, without increasing the short-circuit current. Net Na and Cl absorption in butyrate-Ringer's solution and HCO3-Ringer's solution were identical. Butyrate stimulation of Na (and Cl) absorption was Cl-dependent and prevented by 1 mM mucosal amiloride, an inhibitor of Na-H exchange, but was HCO3-independent and not inhibited by acetazolamide, a carbonic anhydrase inhibitor. In contrast, bicarbonate-stimulated Na (and Cl) absorption was also Cl-dependent and amiloride-sensitive, but was significantly inhibited by acetazolamide. The effect of mucosal butyrate on net Na and Cl absorption was substantially greater than serosal butyrate, which in the presence of bicarbonate did not alter ion transport. The stimulation of Na and Cl absorption by mucosal butyrate was significantly greater than by propionate and acetate, whereas mucosal formate did not alter Na transport. The results of this study permit the following model: short-chain fatty acid stimulation of active Na and Cl absorption involves uptake of the nonionized form of butyrate and the coupling of Na-H and Cl-butyrate exchanges.