The effect of posture on esophageal pH in endoscopy normal reflux disease (ENRD) cases.

PURPOSE OF THE STUDY: Endoscopy Normal Reflux Disease (ENRD) is a common presentation of reflux disease. These patients are symptomatic but do not have abnormal endoscopy findings. They may have pathological intraesophageal reflux. Lifestyle modifications are the mainstay of management of these patients. Posture plays an important role in their management. It was felt that exact quantification of reflux pattern with different postures in ENRD cases should be studied to include it as a part of management of these cases. BASIC PROCEDURES: Fifteen male patients were studied. 24 h ambulatory pH metry was done for all patients. Half an hour recording was studied for various postures: supine, supine with 30 degrees head end elevated, upright, right and left lateral recumbent position. The data of pH metry for half an hour of each of these postures was studied. RESULTS AND INTERPRETATION: All fifteen patients were ENRD cases and were upright refluxers. None of them had an abnormal supine reflux pattern. The percentage time of reflux and the reflux episode duration was significantly low in supine (P<0.05) and supine with 30 degrees head end elevated (P<0.005). CONCLUSION: In our study of 15 upright refluxers, supine with 30 degrees head end elevated and supine position were the postures associated with least reflux. Posture can help reduce the reflux significantly and can be used as an effective means in management.

Erythropoietin levels in lowlanders and high-altitude natives at 3450 m.

BACKGROUND: This study is aimed to determine whether short or prolonged residency at high altitude (HA) elicits erythropoietin (EPO) secretion effectively in subjects who were able to acclimatize and those who were not able to acclimatize and suffered from acute mountain sickness (AMS) and high altitude pulmonary edema (HAPE). METHODS: Plasma EPO was measured in 16 lowland residents (LLR) at sea level (SL) and during 11 d of their sojourn at an altitude of 3450 m. Identical studies were also conducted in LLR acclimatized to HA (LLR-accl), high altitude natives (HAN) and in patients of AMS and HAPE. RESULTS: In LLR at SL, the mean +/- SD EPO levels were 8.93 +/- 3.75 mU x ml(-1), increased significantly after 8 h (20.0 +/- 11.06) of arrival at HA, peaked by day 1 (27.91 +/- 10.74 mU x ml(-1)), and started declining thereafter. The hemoglobin and hematocrit also increased after 8 h of arrival at HA and the increased levels were maintained during sojourn at high altitude. The EPO levels in LLR-accl were found to be significantly higher than the LLR SL values, but were not significantly different in HAN. The EPO levels in patients of AMS were not significantly different than the LLR values during the initial 2 d after arrival at HA but were found to be increased in patients of HAPE. CONCLUSION: Short or prolonged residency at HA is associated with increased secretion of EPO. The EPO response to hypoxia is not significantly altered in AMS but is markedly enhanced in HAPE, which may be due to exaggerated hypoxemia in these patients.

2-aryl-N-tosylazetidines as formal 1,4-dipoles for [4 + 2] cycloaddition reactions with nitriles: an easy access to the tetrahydropyrimidine derivatives.

[reaction: see text] A new synthetic route to 2-aryl-N-tosyl azetidines has been developed starting from N-tosylarylaldimines in two steps in an overall yield of 63-70%. A formal [4 + 2] cycloaddition of these 2-aryl-N-tosylazetidines with nitriles in the presence of BF3.OEt2 has been described for the synthesis of substituted tetrahydropyrimidines. It is proposed that the reaction proceeds in Ritter fashion.

Beta-adrenoreceptor blockade attenuates heat-induced tachycardia,but not the tolerance to the stress.

Ten healthy males (age 34 +/- 3 yr 9 SE) underwent 40 min of heat exposure (WD 39.7.C) after 2 hours of ingesting 120 mg of Propranolol (Inderal; ICI), or a placebo, in a random manner, the exposures being about a week apart. That there was no placebo effect was ensured by giving a control run (no medication). In the placebo trials, the end-experiment heart rate had increased by 52%, while after propranolol the increase was only 43%. Regression analysis showed that with the placebo, the HR increased by 22 beats/min/o rise in core (aural) temperature, while with propranolol, the rise (14 beats/min) was significantly lower (P < 0.02). The various heat strain indices viz the Craig's Index, the Body heat storage (Kilocals/m2/hr), and the effective heat storage were also similar for both the treatments. We conclude that beta-adrenoreceptor activity plays a significant role in producing tachycardia of heat exposure in humans, but blocking this activity with propranolol does not affect tolerance to heat stress.

Peak expiratory flow rates in elderly Indians.

Peak expiratory flow rates were measured in 124 normal elderly men (55-85 yr) using the Wright's peak flow meter. In the less than 60 yrs age group (n = 32; mean age 57.7 yr) the PEFR was 431 +/- 13 lpm, while for the group greater than 60 yr (mean age 69.0 +/- 6.0; n = 92), the PEFR value was 373 +/- 11 1pm. These values are similar to those reported in other Indian studies, suggesting that the ethnic variations amongst Indian subjects do not affect the PEFR. However, the reported values are lower than those observed in Europeans, but greater than those of Chinese. The PEFR regressed at a rate of 4.47 1pm/year increase in age, but is positively correlated to the subjects' height (cm), and their FVC and FEVI. The smokers had a significantly higher PEFR as compared with the non-smokers. This finding was contrary to what was expected.

Calcium channel blockers and the CVS reflex responses during lower body suction.

Nine normal men (mean age 27.6 yr) were exposed to continuous lower-body suction pressure (LBSP) of -20 to -50 mmHg (for 5 min at each level) on four different occasions after having consumed a single oral therapeutic dose of either diltiazem, nifedipine, verapamil, or a placebo, randomly, in a single blind manner. The suction was applied at 12.30 pm in all experiments, while the medications were administered in such a manner so that their expected peak plasma levels would have been achieved at the time of suction application. The cardiovascular reflex effects commenced at a pressure of -30 mmHg, and peaked at -50 mmHg. The increases in the heart rate for all treatments at -50 mmHg was statistically similar (about 16-20 beats/min). The systolic BP fell by about 9 mmHg for the placebo experiments, and this change was not different from the changes produced by the 3 Calcium channel blocker treatments. The diastolic BP increase was about 3 mmHg. The Cardiac index did not vary significantly. Our results suggest that the commonly used Ca++ channel blockers do not adversely affect orthostatic tolerance.

Pd-NHC catalyzed cyclopentannulation of diazabicyclic alkenes with ortho-aryl halides.

Pd-NHC catalyzed cyclopentannulation of diazabicyclic alkenes with ortho- functionalized aryl halides is described. In all the reactions, a single diastereomer of the cyclopentannulated product is observed, and this reaction is very efficient under microwave irradiation.

One-pot synthesis of unsymmetrical N-heterocyclic carbene ligands from N-(2-iodoethyl)arylamine salts.

An approach that provides symmetrical, unsymmetrical, and asymmetric N-heterocyclic carbene (NHC) ligands is reported. Reaction of iodoethanol with aniline provides N-(2-iodoethyl)arylamine salts that are then converted to the corresponding iodide. Reaction with aliphatic or aromatic amines followed by triethyl orthoformate was used to provide 26 different NHC ligands.

Studies on the reaction of aziridines with nitriles and carbonyls: synthesis of imidazolines and oxazolidines.

Reaction of N-tosylaziridines with nitriles and carbonyls to produce imidazolines and oxazolidines has been studied in the presence of a variety of Lewis acids. The reaction is efficient with 1 equiv of BF3.Et2O or Et3OBF4 in CH2Cl2. However, it is catalytic with metal triflates that give the best results for cycloaddition of N-tosylaziridine with nitriles under solvent free conditions. The same reaction with carbonyls proceeds best in CH2Cl2 in the presence of molecular sieves. Among various triflates, Zn(OTf)2 has been found to be the best. The cleavage of the N-Ts bond of the cyclized products has been studied in order to make it more versatile in synthesis. The mechanistic aspect of the reaction has been studied by using chiral aziridines as substrates. These formal [3+2] cycloaddition reactions of aziridines with nitriles and carbonyls proceed in a Ritter fashion.

Pt-catalyzed tandem epoxide fragmentation/pentannulation of propargylic esters.

A Pt-catalyzed pentannulation of propargylic esters containing an epoxide moiety has been developed. The present transformation achieves the formation of cyclopentenone products as single diastereomers in good yields. The observed products likely form from pyran intermediates that undergo an oxa-6pi electrocyclic ring opening to a functionalized dienone, followed by ring closure with an accompanying acyl shift.

Pt-catalyzed pentannulations from in situ generated metallo-carbenoids utilizing propargylic esters.

A highly selective and efficient Pt-catalyzed pentannulation reaction beginning from propargylic esters is described. The key to this reaction is the use of a PtCl2(PPh3)2/PhIO catalyst combination that allows the in situ generation of Pt-carbenoid intermediates, which lead to good yields (61-84%) of the desired pentannulated compounds.

Effects of inhaled nitric oxide and oxygen in high-altitude pulmonary edema.

BACKGROUND: High-altitude pulmonary edema (HAPE) is characterized by pulmonary hypertension, increased pulmonary capillary permeability, and hypoxemia. Treatment is limited to descent to lower altitude and administration of oxygen. METHODS AND RESULTS: We studied the acute effects of inhaled nitric oxide (NO), 50% oxygen, and a mixture of NO plus 50% oxygen on hemodynamics and gas exchange in 14 patients with HAPE. Each gas mixture was given in random order for 30 minutes followed by 30 minutes washout with room air. All patients had severe HAPE as judged by Lake Louise score (6.4+/-0.7), PaO2 (35+/-3. 1 mm Hg), and alveolar to arterial oxygen tension difference (AaDO2) (26+/-3 mm Hg). NO had a selective effect on the pulmonary vasculature and did not alter systemic hemodynamics. Compared with room air, pulmonary vascular resistance fell 36% with NO (P<0.001), 23% with oxygen (P<0.001 versus air, P<0.05 versus NO alone), and 54% with NO plus 50% oxygen (P<0.001 versus air, P<0.005 versus oxygen and versus NO). NO alone improved PaO2 (+14%) and AaDO2 (-31%). Compared with 50% oxygen alone, NO plus 50% oxygen had a greater effect on AaDO2 (-18%) and PaO2 (+21%). CONCLUSIONS: Inhaled NO may have a therapeutic role in the management of HAPE. The combined use of inhaled NO and oxygen has additive effects on pulmonary hemodynamics and even greater effects on gas exchange. These findings indicate that oxygen and NO may act on separate but interactive mechanisms in the pulmonary vasculature.