Preflight versus en route success and complications of rapid sequence intubation in an air medical service

Methacholine chloride bronchoprovocation challenges are performed for the diagnosis and investigation of hyperreactive airways. Over the last 20 yrs various formulations and pH values for the preparation of solutions of methacholine have been described. To determine the stability of methacholine chloride solutions prepared in a variety of buffers with differing pH values and under varying storage temperatures, we measured methacholine concentrations at intervals from 1 to 5 weeks. It was found that methacholine chloride solutions rapidly decompose if the pH is greater than 6 and that decomposition is more rapid as the pH is raised; solutions at pH 9, i.e. bicarbonate buffer, and stored at 27 degrees C have degradation up to 36% after only one week. Solutions of the same pH but prepared in different buffers can have both varied rates of deterioration and different absolute amounts of methacholine hydrolysed, e.g. solutions prepared in pH 9 borate buffer and stored at 27 degrees C have up to 60% degradation after 1 week. Solutions prepared in saline are stable probably because methacholine solutions are weakly acidic. The results emphasise the importance of preparing methacholine chloride in the proper buffers for use in the accurate assessment of airway responsiveness.     

Effects of inhaled nitric oxide on methacholine-induced bronchoconstriction: a concentration response study in rabbits

Inhaled nitric oxide (NO), at a concentration of 80 ppm, counters the increase in respiratory resistance (Rrs) induced by methacholine, but fails to prevent a reduction in lung compliance (Crs) in a rabbit model. This study reports the effects of 3, 30 and 300 ppm of inhaled NO. New Zealand White rabbits were intubated and mechanically ventilated with 30% oxygen during neurolept anaesthesia. Methacholine (3 mg.ml-1) was nebulized, with or without NO inhalation. Inhalation of 3 and 30 ppm NO had no effect on the induced bronchoconstriction, whereas 300 ppm fully blocked the increase in Rrs. The decrease in Crs due to methacholine was not countered by 3, 30 or 300 ppm NO. On the contrary, inhalation of 300 ppm NO in itself decreased Crs from 5.0 +/- 0.1 to 4.3 +/- 0.1 ml.cmH2O-1. Also, mean arterial pressure (60 +/- 7 to 54 +/- 5 mmHg), alveolar-arterial oxygen tension gradient (0.8 +/- 0.8 to 2.3 +/- 1.8 kPa) and methaemoglobin (0.5 +/- 0.2 to 1.5 +/- 0.5%) changed significantly on inhalation of NO 300 ppm prior to methacholine challenge. We conclude that 3 and 30 ppm NO inhalation does not alter methacholine-induced bronchoconstriction. Inhalation of 300 ppm NO blocks an increase in resistance but fails to counter the reduction in compliance due to methacholine. This suggests that the bronchodilating effects of NO in rabbits in vitro are confined to the large airways.     

Methacholine induces wheal-and-flare reactions in human skin but does not release histamine in vivo as assessed by the skin microdialysis technique

A number of investigations have indicated that cholinergic agonists release histamine from isolated mast cells and suggested that cholinergic stimulation releases histamine in vivo. The purpose of this study was to investigate whether the cutaneous wheal-and-flare reaction induced by methacholine challenge in human skin involves histamine release as measured by the skin microdialysis technique. Five hollow dialysis fibers were inserted intradermally in forearm skin in eight healthy subjects. Each fiber was perfused with Kreb's-Ringer bicarbonate at a rate of 3 microliters/min. Dialysates were collected in 2-min fractions before skin challenge and for 20 min after intradermal injection of methacholine 10(-3)-10(-1) M, the vehicle, and a positive control, codeine phosphate 0.3 mg/ml. Histamine was assayed spectrofluorometrically. Methacholine caused a statistically significant dose-related wheal-and-flare reaction, the flare reaction to methacholine 10(-1) M being comparable with that seen with codeine 0.3 mg/ml. No significant histamine release was observed with methacholine, cumulative histamine release of 16 +/- 8 nM by methacholine 10(-1) M being similar to vehicle responses of 15 +/- 9 nM. Histamine release by codeine was 2524 +/- 435 nM. In conclusion, methacholine-induced wheal-and-flare reactions in human skin appeared not to involve histamine release from skin mast cells.     

An in vitro study of the use of chelating agents in cleaning nickel-contaminated human skin: an alternative approach to preventing nickel allergic contact dermatitis

The purpose of this study was to investigate the efficacy of organic ligands in cleaning human skin contaminated with nickel. 4 ligands were investigated, 5-chloro-7-iodoquinolin-8-ol (either as HL(1) or NaL(1)), ethylenediaminetetraacetic acid (either as H4L(2) or Na2H2L(2)), sodium diethyldithiocarbamate (NaL(3)) and L-histidine (HL(4)). The cytotoxicity of these ligands was assessed using HaCaT cells (a transformed human keratinocyte cell line). The cytotoxicity order of the ligands was NaL(1) >Na2H2L(2)>NaL(3)>HL(4). An in vitro methodology for examining nickel removal from viable human skin was developed. This methodology was then used to compare the efficiency of the ligands in removing nickel from skin, both alone and in combination with soap solutions. HL(1) and NaL(3) were no more effective than control solutions in removing nickel over the pH range 2-11. In contrast, both H4L(2) and HL(4) removed between 74 and 87% (mean=82+/-3%) of nickel from human skin over the same pH range. Nickel removal from skin by sodium lauryl ethoxy sulfate (SLES, the active ingredient in most liquid skin cleansers) was independent of concentration and no more effective than phosphate-buffered saline (PBS). The amount of nickel removed by PBS solutions of Na2H2L(2) and HL(4) was significantly greater than the amount removed by SLES and was concentration dependent. An evaluation of nickel removal from skin by commercial solid soap, liquid soap and PBS, both alone and with added Na2H2L(2) or HL(4), was conducted. Commercial liquid soap with added HL(4) was more effective than the untreated soap. PBS with either added Na2H2L(2) or HL(4) was more effective than PBS alone.     

Mid-trimester emergent cerclage: a ten year single institution review

Chronic lung disease (CLD) of prematurity may be caused by a number of insults during mechanical ventilation, including barotrauma and hyperoxia. To evaluate bronchial hyperresponsiveness (BHR) in infants with CLD of prematurity, we measured changes in transcutaneous oxygen tensions (tcPO2) during methacholine inhalation challenge. Twelve infants with CLD and 22 age-matched children without respiratory diseases were enrolled in this study (ages--5 to 36 months; mean age--16.2 months). Serial doses of methacholine were doubled until a 10% decrease in tcPO2 from baseline was reached. The cumulative dose of methacholine inhaled by the time tcPO2 had been reached (Dmin-PO2) was considered to represent the dose at which reactivity to methacholine (RO2meth) had occurred. In the CLD group, Dmin-PO2 (3.50 +/- 0.1 log x milli-units) was significantly lower than in the preterm control infant group (4.31 +/- 0.2 log x milli-units) and the term infant group (4.21 +/- 0.1 log x milli-units) (P = 0.004, P < 0.001). Dmin-PO2 in the preterm control infant group was not significantly different than in the term infant group (P > 0.5). These results suggest that infants who require additional therapeutic oxygen and mechanical ventilation during the early months of life are at risk of developing early-onset, long-lasting respiratory disease that is related to an acquired BHR.     

Significant reduction of medical costs by differentiation therapy with all-trans retinoic acid during remission induction of newly diagnosed patients with acute promyelocytic leukemia. The Japan Adult Leukemia Study Group

OBJECTIVE: For resuscitation of hemorrhagic hypovolemia, we compared the effectiveness of (1) isotonic lactated Ringer's solution (LRS), (2) 2400 mOsm of 7.5% NaCl:6% dextran 70 (HSD), and (3) 2400 mOsm of 7.9% sodium acetate:1.9% NaCl:6% dextran 70 (HAD). DESIGN: In six randomized, blinded experiments for each solution, conscious instrumented adult sheep were hemorrhaged by removing approximately 1.8 L (42 +/- 3 mL/kg) of blood, while maintaining the mean arterial pressure (MAP) at 50 mm Hg for 2 hours. METHODS: Test solutions were infused as needed to restore the cardiac index to baseline. RESULTS: Volume requirements with HAD (236 +/- 29 mL) and HSD (244 +/- 39 mL) were significantly less (p < 0.05) than LRS (3463 +/- 234 mL). Mean arterial pressure was normalized with HSD and LRS, but not with HAD, which resulted in MAPs of 20 to 25 mm Hg less than baseline resulting from a reduced peripheral resistance. Oxygen delivery, however, was significantly higher with HAD during the resuscitation period. Acid-base balance (pH) and oxygen consumption were normalized within 5 minutes of infusion only with HAD. CONCLUSIONS: Small-volume infusion with HAD resulting in "high-flow-low-pressure" resuscitation may offer unique hemodynamic and metabolic advantages for the initial treatment of hemorrhage from trauma.     

Formation of a covalent Nepsilon2-guanylylhistidyl reaction intermediate by the GTP:GTP guanylyltransferase from the brine shrimp Artemia

1. Cardioplegic solutions provide the opportunity to operate on a nonbeating heart and to protect the heart against ischemic injury during cardiac surgery. The components of these solutions are constantly being modified in an effort to find the optimal solution. We studied the effects of colloidal volume replacers such as dextran, HES and gelatin as an isocolloidoosmotic addition to St. Thomas Hospital cardioplegic solution in ischemia-reperfusion injury of isolated rat hearts. 2. In the control group, after a stabilization period of 20 min, the hearts were arrested with St. Thomas Hospital cardioplegic solution for 3 min, then subjected to 30 min of global ischemia. Hearts then were reperfused for 10 min. In the experimental groups, the protocol was the same, but either HES 200/0.5 (50 g/L), modified fluid gelatin (30 g/l) or dextran 70 (25 g/L) were added to the St. Thomas Hospital solution. 3. All hearts were compared for their preischemic and postischemic contractility, heart rate, contractility rate product, coronary flow, lactate dehydrogenase, creatine phosphokinase enzyme leakage and wet/dry weight ratio. 4. All groups had similar contractility (for control, HES, gelatin and dextran groups the values at minute 10 of reperfusion were 59+/-9, 56+/-11%, 61+/-14%, 49+/-14% of initial values [P>0.05, respectively]) and enzyme leakage (lactate dehydrogenase 4.1+/-1.0, 8.1+/-1.5, 5.8+/-1.4, 3.7+/-1.2 [P>0.05] and for creatine phosphokinase 3.9+/-2.5, 6.4+/-3.7, 5.5+/-1.3, 5.5+/-0.8, P>0.05] IU xmin(-1) x g dry tissue(-1) in the reperfusion period, respectively) results as compared with the control group. 5. The addition of isocolloidoosmotic colloids to the cardioplegic solution did not appear to enhance the effectiveness of the crystalloid St. Thomas Hospital cardioplegic solution. If a colloid is to be chosen as a plasma replacer or an additive to priming solution in the preoperative period, or during open-heart surgery, it should be modified fluid gelatin-for no sign of cardiodepression was determined with the use of this agent.     

Inhaled steroids modify bronchial responses to hyperosmolar saline

We investigated the effects of inhaled beclomethasone dipropionate (BDP) on airway sensitivity (provocative dose producing a 20% fall in forced expiratory volume in one second (FEV1) from baseline (PD20)) and reactivity (slope of the dose-response curve) to inhaled aerosols of hyperosmolar (4.5%) saline, and histamine or methacholine. This was an open study on 13 patients referred to the laboratory by their respiratory physician for investigation of their asthma. These challenges were performed on separate days before (initial visit) and 8.8 +/- 0.8 (SD) weeks (range 5.6-12.4 weeks) after (visit 1) a treatment period with BDP (dose range 600-1,500 micrograms.day-1). At visit 1 there was a significant reduction in sensitivity to 4.5% NaCl and histamine/methacholine and in reactivity. The PD20 increased 5.6 fold for 4.5% NaCl and 4.1 fold for histamine/methacholine. All patients remained responsive to histamine/methacholine and a fall in FEV1 > 20% to 4.5% saline was documented in 10 of the 13 patients. We conclude that treatment with BDP reduces sensitivity and reactivity to both osmotic and pharmacological challenge.     

Intragenic Tsc2 somatic mutations as Knudson''s second hit in spontaneous and chemically induced renal carcinomas in the Eker rat model

Membrane conductances during hypoosmotic swelling were characterized in rat astrocytes in primary tissue culture. Using whole cell patch clamp techniques, mean +/- SEM cell conductance in isoosmotic phosphate-buffered saline (PBS) was 55.6 +/- 5.8 pS/pF. Cell conductance (mean +/- SEM) increased from this initial value to 187 +/- 46%, 561 +/- 188%, and 1216 +/- 376% within 9 min of exposure to 220 mOsm, 190 mOsm, and 145 mOsm PBS, respectively. With each of these hypoosmotic exposures, no change occurred in membrane capacitance. When CsCl replaced KCl in the microelectrode solution, a similar conductance increase was obtained at each osmolality. However, when gluconate salts were used in place of chloride salts in the electrode solution, no significant conductance increase was observed with 190 mOsm PBS. With a KCl microelectrode solution, all conductance increase which occurred in 190 mOsm PBS was inhibited by 200 microM niflumic acid, but not by 5 mM BaCl(2). Both niflumic acid and BaCl(2) inhibited 60-80% of the conductance increase of cells in 145 mOsm PBS. Using a microelectrode solution containing taurine as the major anion, membrane conductance increased 5-fold when cells were placed in 250 mOsm medium. This conductance increase was completely inhibited by 200 microM niflumic acid. Thus, independent chloride and potassium conductances are activated by hypoosmotic swelling of cultured astrocytes while plasma membrane area is unaltered. The chloride conductance pathway is activated at a significantly lower degree of hypoosmotic exposure than that which activates the potassium pathway and may be permeable to anionic taurine. These conductance pathways may mediate diffusive loss of potassium, chloride, and taurine from these cells during volume regulation following hypoosmotic swelling.     

Physical fitness influences water turnover and body water changes during trekking

PURPOSE: This study was performed to assess water turnover and changes of body water during a trekking tour at moderate altitude. METHODS: Fifteen healthy normally trained adults participated in a 7-d backpack trek tour in the Swiss Alps (total walking distance: 120.5 km; cumulated altitude difference: 6990 m (uphill) and 7550 m downhill; lowest point: 1285 m; highest point: 3317 m). Total body water and water turnover were measured using deuterium dilution and elimination (oral load of 0.33 g 99.8% D2O per kg body weight, overnight equilibration period, pre- and postdose saliva samples immediately before and after sleep, analysis of D2O concentrations in saliva using Fourier-transform infrared spectroscopy, CV < 1%). Physical training state was assessed after the tour using the lactate-exercise intensity relationship obtained by performing 50-W increments every 3 min on a cycle ergometer. RESULTS: Body water decreased from the evening of day 0 to the evening of day 4 (from 45.3 +/- 7.3 L to 43.4 +/- 7.6 L, P < 0.05), and did not significantly decrease (43.5 +/- 7.9 L) until the evening of day 5 (maximum of trekking exercise intensity). Mean daily water turnover was 5.7 +/- 1.8 L x d(-1) corresponding to 78.7 +/- 17.5 mL x kg(-1) x d(-1). Body water changes and water turnover were significantly related to the exercise intensity obtained at the lactate threshold as well as at the level of 4 mM lactate. CONCLUSIONS: This correlation may be in part explained by differing glycogen content of muscle tissue.     

Mechanism of NaCl and water reabsorption in the proximal convoluted tubule of rat kidney

The role of chloride concentration gradients in proximal NaCl and water reabsorption was examined in superficial proximal tubules of the rat by using perfusion and collection techniques. Reabsorptive rates (Jv), chloride concentrations, and transtubular potential difference were measured during perfusion with solutions (A) simulating an ultrafiltrate of plasma; (B) similar to (A) except that 20 meq/liter bicarbonate was replaced with acetate; (C) resembling late proximal fluid (glucose, amino acid, acetate-free, low bicarbonate, and high chloride); and (D) in which glucose and amino acids were replaced with raffinose and bicarbonate was partially replaced by poorly reabsorbable anions (cyclamate,sulfate, and methyl sulfate). In tubules perfused with solutions A and B, Jv were 2.17 and 2.7 nl mm-1 min-1 and chloride concentrations were 131.5 +/- 3.1 and 135 +/- 395 meq/liter, respectively, indicating that reabsorption is qualitatively similar to free-flow conditions and that acetate adequately replaces bicarbonate. With solution C, Jv was 2.10 nl mm-1 min-1 and potential difference was +1.5 +/- 0.2 mV, indicating that the combined presence of glucose, alanine, acetate, and bicarbonate per se is not an absolute requirement. Fluid reabsorption was virtually abolished when tubules were perfused with D solutions; Jv was not significantly different from zero despite sodium and chloride concentrations similar to plasma; chloride concentration was 110.8 +/- 0.2 meq/liter and potential difference was -0.98 mV indicating that chloride was close to electrochemical equilibrium. These results suggest the importance of the chloride gradient to proximal tubule reabsorption in regions where actively reabsorbable solutes (glucose, alanine, acetate, and bicarbonate) are lacking and provide further evidence for a passive model of NaCl and water transport.     

Discriminative stimulus effects of S(-)-methcathinone (CAT): a potent stimulant drug of abuse

Elevated circulating plasma nonesterified fatty acids (NEFA) may contribute to the insulin resistance and hyperglycemia of non-insulin-dependent diabetes mellitus (NIDDM), and decreasing plasma NEFA could provide a therapeutic benefit. A sustained-release preparation of acipimox, a lipolysis inhibitor, was used in an attempt to decrease circulating plasma NEFA levels long-term, and the effects on glycemic control, insulin resistance, and serum lipids were measured. Sixty NIDDM patients (43 males and 17 females) took part in a randomized controlled trial of acipimox or placebo for 12 weeks. Fasting plasma NEFA levels did not change in acipimox-treated patients (baseline v 12 weeks, 0.84 +/- 0.35 v 0.88 +/- 0.55 mmol x L(-1), mean +/- SD). Fasting blood glucose was unchanged (mean difference v placebo, -0.5 mmol x L(-1); 95% confidence interval [CI], -1.4 to 0.3 mmol x L[-1]), but serum fructosamine decreased (mean difference v placebo, -26 micromol x L(-1); 95% CI, -51 to 0 mmol x L[-1]), as did the standardized hemoglobin A1 ([HbA1] mean difference v placebo, -1.4%; 95% CI, -3.0% to -0.1%). Insulin resistance measured as steady-state plasma glucose during an insulin-dextrose infusion test was unchanged (mean difference v placebo, -1.4 mmol x L(-1); 95% CI, -3.2 to 0.5 mmol x L[-1]). Serum total cholesterol (mean difference v placebo, -0.4 mmol x L(-1); 95% CI, -0.6 to -0.1 mmol x L[-1]), serum apolipoprotein B ([apo B] mean difference v placebo, -0.19 g x L(-1); 95% CI, -0.3 to -0.1 g x L[-1]), and serum triglycerides (mean difference v placebo for pretreatment v posttreatment ratio, 0.59; 95% CI, 0.40 to 0.88) were all lower with acipimox. Serum high-density lipoprotein (HDL) cholesterol (mean difference v placebo, 0.10 mmol x L(-1); 95% CI, -0.05 to 0.3 mmol x L[-1]), serum apo A1 (mean difference v placebo, 0.03 g x L(-1); 95% CI, -0.04 to 0.1 g x L[-1]), and serum lipoprotein(a) ([Lp(a)] acipimox v placebo, 154 (0 to 1,574) v 71 (0 to 1,009), median and range) were unchanged. Despite the lack of change in fasting plasma NEFA levels, acipimox caused a modest beneficial improvement in overall glycemic control and plasma lipids in NIDDM patients and could be a useful agent in the treatment of dyslipidemic NIDDM patients.     

Protein balance in the first week of life in ventilated neonates receiving parenteral nutrition

BACKGROUND: Protein intake is frequently delayed in ill neonates because of concerns about their ability to metabolize substrates. OBJECTIVE: We aimed to determine the factors affecting protein balance in ventilated, parenterally fed newborns during the first week of life. DESIGN: Leucine kinetic studies were performed in 19 neonates by using the [1-(13)C]leucine tracer technique after 24 h of a stable total parenteral nutrition (TPN) regimen. TPN intakes were prescribed by rotating attending physicians, enabling assessment of protein metabolism over a range of clinically used nutrient intakes. RESULTS: Mean (+/-SD) birth weight was 1.497 +/- 0.779 kg, gestational age at birth was 30.3 +/- 4.0 wk, and age at study was 3.9 +/- 1.4 d. Amino acid intakes (AAIs) ranged from 0.0 to 2.9 g x kg(-1) x d(-1). Based on leucine kinetic data, protein balance was calculated as the difference between protein synthesis and catabolism. By multiple regression analysis, AAI was the only predictor associated independently with protein balance (P < 0.01); energy intake, lipid intake, glucose intake, birth weight, and gestational age were not. Both leucine oxidation and nonoxidative leucine disposal rates were significantly correlated with leucine intake (P < 0.0005 and P < 0.01, respectively). Of the 12 infants with AAIs > 1 g x kg(-1) x d(-1), only 1 infant was significantly catabolic (protein balance <-1 g x kg(-1) x d(-1)). There was no evidence of protein intolerance as determined by elevated creatinine (69 +/- 31 micromol/L), plasma urea nitrogen (6.7 +/- 2.53 mmol/L), or metabolic acidosis (pH: 7.36 +/- 0.05). CONCLUSIONS: Ill neonates can achieve a positive protein balance in the first days of life without laboratory evidence of protein toxicity.     

Electrochemical study of some 2-mercapto-5-R-ammino-1,3,4-thiadiazole derivatives using carbon paste electrodes

The electrochemical study of some 2-mercapto-5-R-ammino-1,3,4-thiadiazole derivatives was made by cyclic and linear sweep voltammetry using a carbon paste electrode (CPE, graphite/solid paraffin ratio 2:1) as working electrode and an Ag/AgCl reference electrode. The current-potential curves were recorded in anodic polarisation in -0.1 and +1.3 V range using aqueous solutions and different buffers (between pH 1.2 and 10.0), with 20 or 50 mV s(-1) sweep rate. The oxidation peak appears between +0.65 and +0.70 V due to disulphides formation. The 5-phenyl derivative has two oxidation peaks, the first at +0.45 +/- 0.03 V and the second at +0.65 +/- 0.03 V. The oxidation potentials are pH dependent, decreasing from 0.9 +/- 0.1 V at pH 1.2 to 0.6 +/- 0.1 V at a pH between 8.0 and 10.0. In some potential ranges depending on pKa of molecules the oxidation potential and oxidation current are pH independent. Simple, precise and accurate voltammetric methods for the determination of these compounds were developed and validated in 2.5 x 10(-6)-7.5 x 10(-4) mol l(-1) concentration ranges. The detection limits were 2.3 micromol l(-1) for 5-ammino-, 12.3 micromol l(-1) for 5-acetylammino-, 11.6 micromol l(-1) for 5-allylammino-, and 1.2 micromol l(-1) for 5-phenylammino-2-mercapto-1,3,4 thiadiazole derivatives.     

Correlation of thrombosis with increased platelet turnover in thrombocytosis

There are no readily applicable methods to routinely assess thrombosis risk and treatment response in thrombocytosis. Reticulated platelets (RP) define the most recently released platelets in the circulation, and the RP% has been shown to estimate platelet turnover in thrombocytopenic states. We examined whether increased RP values were associated with thrombotic complications in thrombocytosis. Platelet count, RP%, and absolute RP count were measured at presentation in 83 patients with chronic or transient thrombocytosis, 46 patients with deep vein (DVT) or arterial (ART) thrombosis and normal platelet counts, and 83 healthy controls with normal platelet counts. Chronic thrombocytosis patients presenting with thrombosis (n = 14) had significantly higher RP% (14.7% +/- 10. 1%, mean +/- SD) than asymptomatic chronic thrombocytosis patients (n = 23, RP% = 3.4% +/- 1.8%), healthy controls (3.4% +/- 1.3%), DVT patients (n = 21, 3.8% +/- 2.1%), or ART patients (n = 25, 4.5% +/- 4.1%, P < .05 for all comparisons). Chronic thrombocytosis patients with thrombosis also had significantly higher absolute RP counts than asymptomatic chronic thrombocytosis patients (98 +/- 64 x 10(9)/L [range, 54 to 249 x 10(9)/L] v 30 +/- 13 x 10(9)/L [range, 11 to 51 x 10(9)/L]; P = .0004), whereas healthy controls, DVT, and ART patients had similarly low absolute RP counts (6 +/- 6 x 10(9)/L, 9 +/- 7 x 10(9)/L, and 11 +/- 7 x 10(9)/L, respectively; P > .49). The RP% and absolute RP counts remained significantly higher in chronic thrombocytosis patients with thrombosis when patients were further subdivided into primary myeloproliferative disorders versus secondary thrombocytosis. Similarly elevated RP percentages and absolute counts were also noted in transient thrombocytosis patients with thrombosis (n = 6, 11.5% +/- 4.4% and 90 +/- 46 x 10(9)/L, respectively) when compared with asymptomatic transient thrombocytosis patients (n = 40, 4.5% +/- 2.7% and 35 +/- 16 x 10(9)/L, respectively) and to all control groups (P < .05 for all comparisons). In addition, 7 of 8 thrombocytosis patients who were studied before developing symptoms of thrombosis had elevated absolute RP counts compared with only 1 of 63 thrombocytosis patients who remained asymptomatic. Follow-up studies in seven chronic thrombocytosis patients showed that successful aspirin treatment of symptomatic recurrent thrombosis significantly reduced the RP% from 17.1% +/- 10.9% before therapy to 4.8% +/- 2.0% after therapy; absolute RP counts decreased from 102 +/- 67 x 10(9)/L to 26 +/- 10 x 10(9)/L (P < .01 for both). We conclude that thrombosis in the setting of an elevated platelet count is associated with increased platelet turnover, which is reversed by aspirin therapy. Measurement of reticulated platelets to assess platelet turnover may be useful in evaluating both treatment response and thrombotic risk in thrombocytosis.     

Fluorescence polarization study of a salt bridge between a single chain Fv and its antigen ribonuclease A

The interaction between a single chain Fv (sFv) of the monoclonal antibody 3A21 and its antigen, bovine pancreatic ribonuclease A (RNase A), was studied by site-directed mutagenesis of the hypervariable regions and fluorescence polarization analysis. The affinity constants of wild-type sFv and a mutant sFv D31A (Asp31 of heavy chain was replaced by Ala) for RNase A were found to be 2.7 x 10(7) and 4.7 x 10(6) M(-1) in PBS at pH 7.2 and 37 degrees C, respectively. Whereas the affinity constant of D31A is not affected by NaCl concentration, that of wild-type sFv is almost the same as that of D31A in the presence of more than 1 M NaCl. These results demonstrate that Asp31 of the heavy chain interacts electrostatically with a positively charged amino acid residue of RNase A.     

Importance of endogenous adenosine during ischemia and reperfusion in neonatal porcine hearts

BACKGROUND: Adenosine has several potentially cardioprotective effects. We hypothesized that the effects of endogenous adenosine vary with degree of ischemia and that elevating endogenous levels is protective. METHODS AND RESULTS: Isolated blood-perfused piglet hearts underwent 120 minutes of low-flow ischemia (10% flow) or 90 minutes of zero-flow ischemia, all with 60 minutes of reperfusion. Hearts were treated with either saline, the adenosine receptor blocker 8-sulfophenyltheophylline (8SPT, 300 micromol x L(-1)), or the nucleoside transport inhibitor draflazine (1 micromol x L(-1)). In separate groups, biopsies were obtained before and at the end of ischemia. Compared with saline, 8SPT did not significantly alter functional recovery in either protocol. Draflazine significantly improved percent recovery of left ventricular systolic pressure both in the low-flow protocol (92+/-3% versus 75+/-2% [saline] and 73+/-3% [8SPT], P<.001 for both) and in the zero-flow protocol (76+/-3% versus 59+/-4% [saline] and 46+/-9% [8SPT], P<.05 for both). In the zero-flow protocol, draflazine also significantly reduced ischemic contracture and release of creatine kinase. Tissue adenosine at the end of ischemia was elevated by draflazine compared with saline-treated hearts: after low-flow ischemia to 0.10+/-0.05 versus 0.00+/-0.00 micromol x g(-1) dry wt (P<.05) and after zero-flow ischemia to 1.73+/-0.82 versus 0.15+/-0.03 micromol x g(-1) dry wt (P<.05). CONCLUSIONS: In neonatal porcine hearts, endogenous adenosine produced during ischemia does not influence ischemic injury or functional recovery. Elevating endogenous adenosine by draflazine elicits cardioprotection in both low-flow and zero-flow conditions.     

Technology of Chloride-Ion Utilization from Filtrates of Carbonate Circuit of Nickel Production

The problem of sulphate solution purification, in particular solutions of carbonate branch after nickel precipitation, from chloride ion can be solved effectively by extraction process. Trialkylamine available commercially (TAA) (alkyl—C₈-C₁₀ and C₇-C₉) has been used in this study. The dependences of chloride ion extraction on temperature, pH and composition of aqueous phase, and composition of organic phase have been investigated. Triethylbenzene, kerosene, diesel oil, syntin with different additions (2-ethylhexanol, hexanol, tributylphosphate) were used as the solvents. The optimum composition of organic phase (0.5-0.6 M TAA in kerosene with addition of 2-ethylhexanol) and the conditions of chloride ion extraction from sulphate solutions have been determined. Chloride ion stripping from organic phase was conducted by alkali solutions to obtain a concentrated solution of sodium chloride.

The technology of chloride ion recovery from filtrates of carbonate branch of nickel plant (Norilsk Mining and Metallurgical plant) has been developed and tested on an industrial scale. The initial filtrate contained in g/l: chloride ion I6-I8, sulphate ion 60-65, impurities of metals. After purification, the chloride ion concentration in solution was less than 0.3 g/l (chloride ion recovery was more than 95%). After stripping of chloride ion with alkali solution, the stripping solutions containing 200-220 g/l NaCl and < 2 g/l sulphate ion. The stripping solutions underwent an electrolysis to obtain chlorine and sodium hydroxide solutions.

The developed technology allows recovery of chloride ion from sulphate solution.     

Hamstrings and psoas lengths during normal and crouch gait: implications for muscle-tendon surgery

OBJECTIVE: To study the relative contribution of the lung and the chest wall on the total respiratory system mechanics, gas exchange, and work of breathing in sedated-paralyzed normal subjects and morbidly obese patients, in the postoperative period. SETTING: Policlinico Hospital, University of Milan, Italy. METHODS: In ten normal subjects (normal) and ten morbidly obese patients (obese), we partitioned the total respiratory mechanics (rs) into its lung (L) and chest wall (w) components using the esophageal balloon technique together with airway occlusion technique, during constant flow inflation. We measured, after abdominal surgery, static respiratory system compliance (Cst,rs), lung compliance (Cst,L), chest wall compliance (Cst,w), total lung (Rmax,L) and chest wall (Rmax,w) resistance. Rmax,L includes airway (Rmin,L) and "additional" lung resistance (DR,L). DR,L represents the component due to viscoelastic phenomena of the lung tissue and time constant inequalities (pendelluft). Functional residual capacity (FRC) was measured by helium dilution technique. RESULTS: We found that morbidly obese patients compared with normal subjects are characterized by the following: (1) reduced Cst,rs (p < 0.01), due to lower Cst,L (55.3 +/- 15.3 mL x cm H2O-1 vs 106.6 +/- 31.7 mL x cm H2O-1; p < 0.01) and Cst,w (112.4 +/- 47.4 mL x cm H2O-1 vs 190.7 +/- 45.1 mL x cm H2O-1; p < 0.01); (2) increased Rmin,L (4.7 +/- 3.1 mL x cm H2O x L-1 x s; vs 1.0 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01) and DR,L (4.9 +/- 2.6 mL x cm H2O x L-1 x s; vs 1.5 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01); (3) reduced FRC (0.665 +/- 0.191 L vs 1.691 +/- 0.325 L; p < 0.01); (4) increased work performed to inflate both the lung (0.91 +/- 0.25 J/L vs 0.34 +/- 0.08 J/L; p < 0.01) and the chest wall (0.39 +/- 0.13 J/L vs 0.18 +/- 0.04 J/L; p < 0.01); and (5) a reduced pulmonary oxygenation index (PaO2/PAO2 ratio). CONCLUSION: Sedated-paralyzed morbidly obese patients, compared with normal subjects, are characterized by marked derangements in lung and chest wall mechanics and reduced lung volume after abdominal surgery. These alterations may account for impaired arterial oxygenation in the postoperative period.     

Rabbit lens and retina phosphorylate glucose through a glucokinase-like enzyme: study in normal and spontaneously hyperglycemic animals

After having previously shown that some noninsulin-sensitive tissues (capillaries and optic nerve) phosphorylate glucose in a concentration-dependent manner through a glucokinase-like enzyme, here, we report data on glucose phosphorylation in rabbit lens and retina at various glucose concentrations (1, 5, 10, 25, 50, and 100 mmol/L). In the 3000 g supernatant of lens and retina homogenates from two separate groups of female albino rabbits ten animals in each group; 1.8-2.0 kg body weight; mean +/- SEM morning glycemia: 8.19 +/- 0.28 and 8.12 +/- 0.24 mmol/L, respectively) was assayed glucose phosphorylating activity (NADP reduction measured as change in optical density at 366 nm at pH 7.5). The enzyme activity did not reach the maximum at low glucose concentration (1 mmol/L), as it occurs in several tissues, but increased progressively in both tissues with the increase in glucose concentration. Values (mean +/- SEM) for lens were 0.197 +/- 0.031 nmol/min/mg protein at 1 mmol/L and 0.327 +/- 0.051 (the highest value) at 50 mmol/L glucose (+65.99%, p < 0.01; r = 0.31, p < 0.05). Values for retina were 36.02 +/- 2.12 at 1 mmol/L glucose and 42.48 +/- 2.79 (the highest value) at 25 mmol/L glucose (+17.93%, p < 0.001; r = 0.32, p < 0.05). These kinetic characteristics, somewhat reminiscent of those shown by hepatic glucokinase, are still more pronounced when we calculated the "glucokinase component," obtained by subtracting the activity at 1 mmol/L glucose (hexokinase component) from that at the highest glucose concentration (total glucose phosphorylating activity). In five rabbits of similar age and weight, with spontaneous hyperglycemia (mean +/- SEM morning glycemia: 11.71 +/- 0.60) glucose phosphorylation in the retina was lower than normal, value at pH 7.5 and 1 mmol/L glucose being 24.52 +/- 2.20 versus 36.02 +/- 2.12 of normal animals (-31.93%, p < 0.01). This, if occurs also in other tissues, could contribute to the hyperglycemia by reducing glucose utilization. In these animals, however, the glucose phosphorylating activity retained the responsivity to increasing glucose concentrations, with value at 100 mmol/L of 28.65 +/- 2.10, corresponding to + 16.84% over the value at 1 mmol/L (p < 0.01). Therefore, the actual glucose phosphorylation in the retina of these animals would depend both upon the enzyme level (which is reduced) and glucose concentration (which is increased). Due to the in vivo inhibition of the hexokinase component by glucose 6-phosphate, the glucokinase component in retina and lens may be predominant in vivo, making the stimulating effect of hyperglycemia much more important than it would appear from our in vitro data. This might play a role in the chronic diabetic complications.