Incremental effects of 28 days of beta-alanine supplementation on high-intensity cycling performance and blood lactate in masters female cyclists.

Within the aging population, there exists a subset of individuals termed masters athletes (MA). As masters-level competition increases in popularity, MA must find methods to enhance individual athletic performance. Longitudinal beta-alanine (BA) supplementation is suggested to enhance physical capability during exercise; however, these effects have not been evaluated in MA. To examine the longitudinal effects of BA on time to exhaustion (TTE), total work completed (TWC), and lactate clearance in female MA cyclists. Twenty-two female MA (age = 53.3 ± 1.0) participated in this double-blind design. Subjects were randomly assigned to BA (n = 11; 800 mg BA + 8 g dextrose) or placebo (PLA; n = 11; 8 g dextrose) groups and supplemented 4 doses/day over 28 days. Every 7 days, subjects completed a cycling TTE at 120% VO2max, and TWC was calculated. Blood lactate was measured at baseline, immediate post, and 20-min post each TTE. No significant differences existed between groups for any variable at baseline (p > 0.05). After 28 days supplementation, BA had greater TTE (23 vs 1% change) and TWC (21 vs 2% change) than PLA (p < 0.05). Following the 20-min TTE recovery, lactate was 24% lower in BA compared to PLA (4.35 vs. 5.76 mmol/L, respectively). No differences existed for variables during intermittent weeks. 28 days of BA supplementation increased cycling performance via an enhanced time to exhaustion and total work completed with associated lactate clearance during passive rest in female MA.

Treatment of congenital pulmonary lymphangiectasia using ethiodized oil lymphangiography.

Historically, congenital pulmonary lymphangiectasia (CPL) has had poor treatment outcomes despite aggressive therapy. There are recent reports of ethiodized oil (Lipiodol) lymphangiography successfully treating lymphatic leakage in adults. In this report, we describe two infants with CPL complicated by chylothoraces successfully treated by instillation of ethiodized oil into the lymphatic system. Congenital atresia of the thoracic duct was demonstrated on the lymphangiogram in both patients before treatment. Both patients have shown good short-term outcomes without supplemental oxygen or fat restricted diets at 9 months of age. Ethiodized oil lymphangiography represents a new treatment modality for some patients with CPL.

Ethanol and its non-oxidative metabolites profoundly inhibit CFTR function in pancreatic epithelial cells which is prevented by ATP supplementation.

Excessive alcohol consumption is a major cause of acute pancreatitis, but the mechanism involved is not well understood. Recent investigations suggest that pancreatic ductal epithelial cells (PDECs) help defend the pancreas from noxious agents such as alcohol. Because the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel plays a major role in PDEC physiology and mutated CFTR is often associated with pancreatitis, we tested the hypothesis that ethanol affects CFTR to impair ductal function. Electrophysiological studies on native PDECs showed that ethanol (10 and 100 mM) increased basal, but reversibly blocked, forskolin-stimulated CFTR currents. The inhibitory effect of ethanol was mimicked by its non-oxidative metabolites, palmitoleic acid ethyl ester (POAEE) and palmitoleic acid (POA), but not by the oxidative metabolite, acetaldehyde. Ethanol, POAEE and POA markedly reduced intracellular ATP (ATPi) which was linked to CFTR inhibition since the inhibitory effects were almost completely abolished if ATPi depletion was prevented. We propose that ethanol causes functional damage of CFTR through an ATPi-dependent mechanism, which compromises ductal fluid secretion and likely contributes to the pathogenesis of acute pancreatitis. We suggest that the maintenance of ATPi may represent a therapeutic option in the treatment of the disease.

The determination of glycyrrhizic acid in Glycyrrhiza uralensis Fisch. ex DC. (Zhi Gan Cao) root and the dried aqueous extract by LC-DAD.

A rapid, sensitive and specific reversed phase high-performance liquid chromatographic (LC) method with photodiode array detection (DAD) has been developed for the determination of glycyrrhizic acid in both the raw herb and a commercially prepared dried aqueous extract of Glycyrrhiza uralensis Fisch. ex DC. root (Zhi Gan Cao, liquorice). It was determined that extracting the raw herb in aqueous methanol (50:50 v/v) by sonication for 2 x 30 min was the most efficient sample preparation. Baseline resolution of the glycyrrhizic acid peak was achieved on a Varian Polaris RP C18-A (250 mm x 4.6 mm, 5 microm packing) column using an isocratic mobile phase consisting of 0. v aqueous phosphoric acid and acetonitrile in the ratio 60:40 v/v. Chromatograms were monitored between 200 and 400 nm for peak purity assessments, with quantitation performed at 254 nm. Glycyrrhizic acid calibration curves in the concentration range of 14-558 microg/ml were prepared on the day of analysis. Curve fitting was by the least-squares method, with correlation coefficients of >0.9998 obtained each time. The average recovery at three spike levels (50, 100, 200%) was of 95.91+/-1.05% and 98.36+/-3.45% (+/-S.D., n=7) for the spiked raw herb and dried aqueous extract respectively. The limit of detection and limit of quantitation was 0.52 and 1.72 mg/g respectively for the raw herb, and 0.75 and 2.51 mg/g respectively for the dried aqueous extract. Identity confirmation of the chromatographic peak was achieved by (-) electrospray ionisation tandem mass spectrometry. The concentration of glycyrrhizic acid in the root and dried aqueous extract was found to be 31.1+/-0.2 and 40.4+/-0.3mg/g (+/-S.D., n=7) respectively.

Effects of bile acids on pancreatic ductal bicarbonate secretion in guinea pig.

BACKGROUND AND AIMS: Acute pancreatitis is associated with significant morbidity and mortality. Bile reflux into the pancreas is a common cause of acute pancreatitis and, although the bile can reach both acinar and ductal cells, most research to date has focused on the acinar cells. The aim of the present study was to investigate the effects of bile acids on HCO(3)(-) secretion from the ductal epithelium. METHODS: Isolated guinea pig intralobular/interlobular pancreatic ducts were microperfused and the effects of unconjugated chenodeoxycholate (CDC) and conjugated glycochenodeoxycholate (GCDC) on intracellular calcium concentration ([Ca(2+)](i)) and pH (pH(i)) were measured using fluorescent dyes. Changes of pH(i) were used to calculate the rates of acid/base transport across the duct cell membranes. RESULTS: Luminal administration of a low dose of CDC (0.1 mM) stimulated ductal HCO(3)(-) secretion, which was blocked by luminal H(2)DIDS (dihydro-4,4'-diisothiocyanostilbene-2,2'-disulfonic acid). In contrast, both luminal and basolateral administration of a high dose of CDC (1 mM) strongly inhibited HCO(3)(-) secretion. Both CDC and GCDC elevated [Ca(2+)](i), and this effect was blocked by BAPTA-AM (1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid), caffeine, xestospongin C and the phospholipase C inhibitor U73122. BAPTA-AM also inhibited the stimulatory effect of low doses of CDC on HCO(3)(-) secretion, but did not modulate the inhibitory effect of high doses of CDC. CONCLUSIONS: It is concluded that the HCO(3)(-) secretion stimulated by low concentrations of bile acids acts to protect the pancreas against toxic bile, whereas inhibition of HCO(3)(-) secretion by high concentrations of bile acids may contribute to the progression of acute pancreatitis.

The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent.

L-theanine (N-ethyl-L-glutamine) or theanine is a major amino acid uniquely found in green tea. L-theanine has been historically reported as a relaxing agent, prompting scientific research on its pharmacology. Animal neurochemistry studies suggest that L-theanine increases brain serotonin, dopamine, GABA levels and has micromolar affinities for AMPA, Kainate and NMDA receptors. In addition has been shown to exert neuroprotective effects in animal models possibly through its antagonistic effects on group 1 metabotrophic glutamate receptors. Behavioural studies in animals suggest improvement in learning and memory. Overall, L-theanine displays a neuropharmacology suggestive of a possible neuroprotective and cognitive enhancing agent and warrants further investigation in animals and humans.

Bacterial biodegradation of aliphatic sulfides under aerobic carbon- or sulfur-limited growth conditions.

AIMS: To isolate bacteria capable of cleaving aliphatic carbon-sulfur bonds as potential biological upgrading catalysts for the reduction of molecular weight and viscosity in heavy crude oil. METHODS AND RESULTS: Thirty-one bacterial strains isolated from enrichment cultures were able to biotransform model compounds representing the aliphatic sulfide bridges found in asphaltenes. Using gas chromatography and mass spectrometry, three types of attack were identified: alkyl chain degradation, allowing use as a carbon source; nonspecific sulfur oxidation; and sulfur-specific oxidation and carbon-sulfur bond cleavage, allowing use as a sulfur source. Di-n-octyl sulfide degradation produced octylthio- and octylsulfonyl-alkanoic acids, consistent with terminal oxidation followed by beta-oxidation reactions. Utilization of dibenzyl sulfide or 1,4-dithiane as a sulfur source was regulated by sulfate, indicating a sulfur-specific activity rather than nonspecific oxidation. Finally, several isolates were also able to use dibenzothiophene as a sulfur source, and this was the preferred organic sulfur substrate for one isolate. CONCLUSIONS: The use of commercially available alkyl sulfides in enrichment cultures gave isolates that followed a range of metabolic pathways, not just sulfur-specific attack. SIGNIFICANCE AND IMPACT OF THE STUDY: These results give new insight into biodegradation of organosulfur compounds from petroleum and for biotreatment of such compounds in chemical munitions.

Investigation of the effects of extracts of Manilkara zapota (L.) P. van Royen on blood pressure and heart rate of rats

The objective of the study was to investigate the hypotensive effect produced by leaf extracts of Manilkara zapota. Methanol extracts of Manilkara zapota leaves were prepared using a soxhlet apparatus. The methanol was removed with a rotor evaporator. Sprague-Dawley rats were anaesthetized with urethane (1.2 mg/kb) and doses of 0.63, 1.25, 2.5, 5.0, 10.0 and 20.0 mg/kg body weight of extract were administered intavenously. Saline (0.9 percent) was given as a control. The effects on blood pressure and heart rate were recorded using a Pressure transducer (Spectramed model 23XL) coupled to a Grass polygraph (model 79E). The plant extract showed a dose-related hypotensive activity and no significant change in heart rate (P.0.05). Toxicity was observed with doses greater than 20mg/kg body weight. These results indicate that Manilkara zapota leaf tea used in folklore medicine to treat hypertension does indeed show various degrees of hypotensive activity when tested in lab animals. However, larger doses were toxic. It is therefore necessary to assess the beneficial as well as the adverse effects of this herb before usage by the hypertensive patient

Pharmacological evaluation of some local plant extracts claimed to be used abortifacients in folklore practice

OBJECTIVE: Several local plant extracts are used in folklore practice as abortifacients. The objectives was to determine the scientific basis, if any, for these claims. METHODS: Aqeous extracts were prepared from 6 plants collected from St.Thomas, Jamaica: Leonotis nepetifolia (LN), Mentha pulegium (MP), Phyllanthus amarus (PA), Stachytarpheta jamaicensis (SJ), Gliricidia sepium (GS) and Wedelia gracilis (WG). The extracts were tested for contractile activity on isolated mouse uteri maintained in de Jalons solution. The effects of indomethacin and atropine on the contractions were used to indicate the possible mechanism of action. RESULTS: Three plant extracts (LN, MP and PA) produced dose-dependent contractions of the non-pregnant and pregnant mouse uteri. No contractions were observed with the other three extracts (SJ, GS, and WG). The contractions produced by MP were significantly reduced by indomethacin (p<0.05) but not by atropine. Contractions produced by LN and MP were blocked by either drug. Pregnant mice given LN litterd with live offspring within 24 hours. CONCLUSIONS: Of the 6 plants evaluated, 3 contracted the uterus in vitro but only one (LN) had a significant action in vivo. The contractile effect of MP may possibly be mediated via prostaglandins. However, this plant extract showed significant toxicity in vivo. (AU)

Prototype algorithm for automated determination of gastric slow wave characteristics.

An algorithm for determining the frequency and propagation time of the gastric slow wave has been designed for integration into a demand gastric pacing system. The algorithm analyses the serosal activity in both the time and frequency domains, and the results are compared to produce a conclusion only when the values are within 5% of each other. Thus, the probability of inappropriate intervention is reduced, at the expense of unidentified segments. The system is verified by comparing the conclusions produced by the algorithm with conclusions from hand analysis of seven canine and one human serosal recordings. The algorithm correctly identifies the slow-wave frequency in the distal portion of the stomach for 90% of the segments, while producing no incorrect results. Slow-wave propagation times in the antrum are correctly identified for 84% of the segments, with no incorrect identifications.

Bradykinin regulation of salt transport across mouse inner medullary collecting duct epithelium involves activation of a Ca(2+)-dependent Cl(-) conductance.

The mechanism by which bradykinin regulates renal epithelial salt transport has been investigated using a mouse inner medullary renal collecting duct cell-line mIMCD-K2. Using fura-2 loaded mIMCD-K2 cells bradykinin (100 nM) has been shown to induce a transient increase in intracellular Ca(2+) via activation of bradykinin B2 receptors localized to both the apical and basolateral epithelial cell surfaces. In mIMCD-K2 epithelial cell-layers clamped in Ussing chambers, 100 nM bradykinin via apical and basolateral bradykinin B2 receptors stimulated a transient increase in inward short-circuit current (I:(sc)) of similar duration to the increase in intracellular Ca(2+). Replacements of the bathing solution Na(+) by the impermeant cation, N-methyl-D-glucamine and of Cl(-) and HCO(3)(-) by the impermeant anion gluconate at either the apical (no reduction) or basal bathing solutions (abolition of the response) are consistent with the bradykinin-stimulated increase in inward I:(sc) resulting from basal to apical Cl(-) (anion) secretion. Using the slow whole cell configuration of the patch-clamp technique, bradykinin was shown to activate a transient Cl(-) selective whole cell current which showed time-dependent activation at positive membrane potentials and time-dependent inactivation at negative membrane potentials. These currents were distinct from those activated by forskolin (CFTR), but identical to those activated by exogenous ATP and are therefore consistent with bradykinin activation of a Ca(2+)-dependent Cl(-) conductance. The molecular identity of the Ca(2+)-dependent Cl(-) conductance has been investigated by an RT - PCR approach. Expression of an mRNA transcript with 96% identity to mCLCA1/2 was confirmed, however an additional but distinct mRNA transcript with only 81% of the identity to mCLCA1/2 was identified.

The qualities of an effective mentor from the student nurse's perspective: findings from a longitudinal qualitative study.

Parker and Carlisle (Journal of Advanced Nursing 24, 771-778) argue that there is a scarcity of empirical research focusing on issues such as supernumerary status and mentorship in Project 2000 courses from the students' perspective. This paper presents the findings of a longitudinal cohort study using Grounded Theory to discover the effect(s) of mentorship on student nurses following the introduction of the 1992 programme of education leading to a Diploma of Higher Education in Nursing and registration with the United Kingdom Central Council (UKCC). The cohort consisted of 10 students from a large Scottish College of Nursing & Midwifery who were interviewed on five occasions during the three years of their course. Students also kept a diary to record their thoughts and experiences regarding mentorship during their practice placements. In addition, a further seven students volunteered to participate by diary only. Data were analysed with the aid of NUD.IST and subjected to the constant comparative method of analysis. Findings indicate that Diploma students quickly lose their idealistic view of their mentor and over time develop an insight into the qualities they perceive are required of an effective mentor. Students quickly become aware of the importance of choosing good role models and learning their own mentor's likes and dislikes as they realize this impinges on the outcome of their assessment. As students move into their Branch programme, a gradual distancing from their mentor is evident. This coincides with a development in their confidence, skills and a holistic perspective of care.

PspA, a protection-eliciting pneumococcal protein: immunogenicity of isolated native PspA in mice.

PspA is a surface exposed virulence factor of S. pneumoniae that can elicit protective immunity to pneumococcal sepsis in mice. It can be released from pneumococci by washing them with a solution containing 2% choline chloride, by growing pneumococci in media containing 1.2% choline chloride, or by growing pneumococci in media in which the choline has been replaced by ethanolamine. Our results indicate that PspA is the major protection-eliciting antigen in each of these preparations. Two injections of < or = 1 microgram of native PspA purified by use of a choline-Sepharose column are highly immunogenic in BALB/c and CBA/N mice, and even in the absence of adjuvant can elicit protection against otherwise fatal sepsis with 100 times the LD50 of S. pneumoniae. Fragments comprising the N-terminal 115 and 245 amino acids of PspA were able to elicit protection but only in the presence of complete Freund's adjuvant (CFA). In the absence of CFA the 245 amino acid fragment was less than 1/100 as immunogenic as native PspA.

Herbs: multicultural folk medicines.

Herbs have been used by man since antiquity for the prevention and treatment of illness. In the past few years, an increased interest in herbs seems to parallel the back-to-nature movement in the United States. While many herbs can be helpful, others pose potential threats. An examination of the cultural roots and general uses of herbs can prove helpful to the nurse conducting a patient interview.

Icterus in bob veal calves and its association with lack of colostrum intake and high serum creatine kinase activity.

Icterus condemnations compose a substantial proportion (41%) of total condemnations of bob veal, the class of veal composed of calves < 3 weeks old and weighing up to 68 kg. At postmortem examination, bob veal condemned because of icterus have generalized yellow discoloration of tissues, which is commonly associated with large, yellow liver (fatty liver), and a paucity of other gross pathologic changes. To establish that the generalized yellow discoloration was attributable to high tissue bilirubin concentrations and to examine the underlying mechanism(s) that might be responsible, blood samples and tissue specimens were obtained from clinically normal and icteric bob veal calves at slaughter. For comparison, blood samples were collected from clinically normal, 1- to 5-day-old Holstein calves being raised on local dairy farms. Hematologic and serum biochemical analyses were obtained for the 3 groups of calves (normal local, normal slaughter, and icteric slaughter), and tissues of slaughter calves were examined for histologic evidence of inflammatory or degenerative changes. Mean +/- SD total bilirubin concentration and creatine kinase (CK) activity in icteric bob veal (3.3 +/- 0.8 mg/dl; 869 +/- 788 U/L), normal bob veal (1.4 +/- 0.7 mg/dl; 486 +/- 890 U/L), and normal local calves (0.5 +/- 0.2 mg/dl; 156 +/- 158 U/L) were significantly different. When data for both normal and icteric bob veal calf groups were combined for analysis, total bilirubin concentration regressed significantly on hepatic lipid scores (P = 0.00003) and CK activity (P = 0.00049). Colostrum consumption was determined by measuring serum total protein concentration and serum gamma-glutamyltransferase activity. Bob veal calves that had not consumed colostrum had significantly higher total bilirubin (P = 0.00005) and CK (P = 0.0008) values. It was concluded that normal and icteric bob veal calves have significant increase in total bilirubin concentration, and icterus of bob veal calves is secondary to unconjugated hyperbilirubinemia. Lack of colostrum consumption was strongly correlated with icterus in bob veal calves.

Dimensional growth and extracellular matrix accumulation by neonatal rat mandibular condyles in long-term culture.

Mandibular condyles in organ culture commonly have been used as a model system for examination of the factors that influence skeletal growth and development. The work reported here complements previously published histological studies by providing quantitative temporal information on growth and matrix accumulation. Condyles maintained for as long as 5 weeks in serum-free and 1% serum-supplemented culture media were found to remain viable and metabolically active as demonstrated by continued dimensional growth as well as cell and matrix accumulation. Growth occurred by a combination of cell proliferation, matrix synthesis and accumulation, and cell hypertrophy (with the latter two mechanisms dominating). Increases in tissue volume correlated directly with increased glycosaminoglycan content; both increased 7-fold over 5 weeks. In comparison with serum-free culture, after 35 days in medium containing 1% serum, glycosaminoglycan content was 24% lower and collagen content was 36% higher, whereas dry weight, condyle length, and DNA content were not significantly different; in addition, histological observation suggested that, for samples cultured with serum, chondrogenic phenotype had been lost from some regions. The temporal behavior for all growth parameters exhibited a transient phase 1-2 weeks in duration followed by a steady-state period in which dimensions and tissue constituents or content increased at a constant or near constant rate. Comparison of the rates of incorporation of [35S]sulfate with glycosaminoglycan content in serum-free cultures suggests that the loss of glycosaminoglycan occurs only initially or is negligible; therefore, under these baseline conditions, cartilage glycosaminoglycan content reflects the biosynthetic rate. The high degree of reproducibility seen during steady-state growth suggests that these data provide reliable baseline information and further supports the notion that this model system is useful for investigation of the effects of specific physical factors on in vitro growth and development.