Betel quid chewing, cigarette smoking and alcohol consumption related to oral cancer in Taiwan

A hospital-based case-control study of matched pairs was conducted to explore (a) the relationship between the use of betel quid chewing, cigarette smoking, alcohol drinking and oral cancer and (b) synergism between these factors. The case group consisted of 104 male and 3 female oral cancer patients and these were compared with 194 male and 6 female matched controls. We found by univariate analysis that alcohol consumption, smoking, betel quid chewing, educational level and occupation were associated with oral cancer. The adjusted odds ratios were to be found elevated in patients who were smoking and betel quid chewing. After adjusting for education and occupation covariates, the incidence of oral cancer was computed to be 123-fold higher in patients who smoked, drank alcohol and chewed betel quid than in abstainers. The synergistic effects of alcohol, tobacco smoke and betel quid in oral cancer were clearly demonstrated, but there was a statistically significant association between oral cancer and betel quid chewing alone. Swallowing betel quid juice (saliva extract of betel quid produced by chewing) or including unripened betel fruit in the quid both seemed to enhance the risks of contracting oral cancer.

Risk factors for primary lung cancer among non-smoking women in Taiwan

BACKGROUND

Although cigarette smoking is considered to be the most important cause of lung cancer, smoking behaviour cannot fully explain the epidemiological characteristics of lung cancer in Taiwanese women, who rarely smoke but contract lung cancer relatively often. There are other causes of lung cancer that have produced variability in lung cancer incidence.

METHODS

A case-control study involving interviews with 117 female patients (including 106 non-smoking) suffering from lung cancer and the same number of individually matched hospital controls was conducted in Kaohsiung, Taiwan between 1992 and 1993. The questionnaire administered to cases and controls collected information on cigarette smoking and suspected risk factors for lung cancer. Multivariate logistic regression analysis was applied to assess smoking for all women and suspected risk factors for non-smoking women.

RESULTS

The relationship between cigarette smoking and lung cancer was statistically significant although only a small proportion (9.4%) of female patients had smoked. However, the risk of contracting cancer for non-smoking women appears to be associated with certain cooking practices, especially preparing meals in kitchens not equipped with a fume extractor at cooking age of 20-40 years (odds ratio [OR] = 8.3; 95% confidence interval [CI]: 3.1-22.7. These factors and a history of pulmonary tuberculosis plus low consumption of fresh vegetables explained 78% of the summary attributable risks for non-smoking women in a multivariate logistic regression model.

CONCLUSIONS

Exposure to fumes from cooking oils, when not reduced by an extractor, may be an important factor in causing lung cancer in non-smoking Taiwanese women.

Tumour necrosis factor (cachectin) induces phospholipase A2 activity and synthesis of a phospholipase A2-activating protein in endothelial cells

Tumour necrosis factor (TNF) is an important mediator of endotoxin-induced vascular collapse and other inflammatory reactions. Eicosanoids have been implicated in the pathogeensis of these responses. In order to explore further the potential interactions between TNF and eicosanoid metabolism in eliciting vascular responses, we studied the effects of TNF on the bovine endothelial cell line CPAE. TNF induced cellular retraction observed by light microscope. This morphological change was monitored by the passage of iodinated protein A between adjacent cells and by release of [3H]arachidonic acid metabolites from cells. Both the morphological and functional responses were abrogated by inhibition of eicosanoid synthesis with BW755c. The release of [3H]arachidonic acid metabolites appeared to be mediated by a transient increase in phospholipase A2 activity. Phospholipase C activity was not affected by TNF. The maximal increase in phospholipase A2 activity occurred at 5 min following the addition of TNF. Phospholipase A2 activation, [3H]arachidonic acid-metabolite synthesis and passage of iodinated protein A, required both RNA and protein synthesis and were associated with an increase in the synthesis of a recently described phospholipase A2-activating protein. The Bordetella pertussis toxin, islet-activating protein, also inhibited the increase in phospholipase A2 activity, the release of [3H]arachidonic acid metabolites and the passage of iodinated protein A, suggesting that the TNF receptor-ligand interaction resulting in cellular retraction, phospholipase A2 activation and eicosanoid synthesis, is coupled through the Ni guanine nucleotide regulatory protein in these cells.

Noradrenergic and serotonergic blockade inhibits BDNF mRNA activation following exercise and antidepressant

Antidepressants and physical exercise have been shown to increase the transcription of hippocampal brain-derived neurotrophic factor (BDNF). Much evidence regarding the initial actions of antidepressant medications as well as exercise leads to the hypothesis that noradrenergic (NE) and/or serotonergic (5-HT) activation is a key element in the BDNF transcriptional elevation common to both interventions. Currently, we used short-term beta-adrenergic, 5-HT(1A), or 5-HT(2A/C) receptor blockade to characterize the influence of NE and 5-HT systems on BDNF transcription during physical exercise and antidepressant treatment. In situ hybridization revealed that beta-adrenergic blockade significantly blunted the BDNF mRNA elevations due to exercise, and also inhibited the modest elevations in the CA3 and dentate gyrus following short-term treatment with tranylcypromine. In contrast, 5-HT(2A/C) blockade only minimally altered exercise-induced BDNF mRNA levels, but inhibited up-regulation of BDNF transcription via tranylcypromine. Finally, 5-HT(1A) blockade did not inhibit exercise-induced BDNF mRNA elevations, but significantly enhanced levels above those achieved with exercise alone in the CA4. These results suggest that NE activation via beta-adrenergic receptors may be essential for both exercise and antidepressant-induced BDNF regulation. 5-HT(1A) and 5-HT(2A/C) activation, on the other hand, appear to be most important for antidepressant-induced BDNF regulation, but may also participate significantly in exercise-induced regulation in the CA4.

Norepinephrine induces BDNF and activates the PI-3K and MAPK cascades in embryonic hippocampal neurons

Both antidepressant treatment and physical exercise have been shown to increase circulating levels of norepinephine (NE) and hippocampal brain-derived neurotrophic factor (BDNF). Increases in BDNF have been shown to be associated with enhanced dendritic arborization and neuronal survival, which forms the theoretical basis of the Neurotrophin Hypothesis of antidepressant action. Using isolated embryonic hippocampal neurons and immunoblotting, we show that application of NE increases BDNF and phosphorylated Trk, and that these increases can be prevented by ERK and PI-3K inhibitors. In addition, NE-induced increases in phospho-ERK2 and PI-3K were each suppressed by a PI-3K and MAPK inhibitor, respectively. Furthermore, phosphorylation of cAMP-response element binding (CREB) protein was also increased by NE and brought down to baseline levels by MAPK and PI-3K inhibitors. And finally, because both the MAPK and PI-3K inhibitors suppress phosphorylation of both TrkB (upstream) and CREB (downstream), these results indicate that NE-induced BDNF expression follows a cyclic pathway, reminiscent of a positive feedback loop. The results of this study provide an in vitro model of the intracellular signaling mechanisms activated by NE, via ligand-G-protein-coupled receptor (GPCR)-to-BDNF-RTK transactivation, that is putatively thought to occur in vivo as a result of excitatory neural activity.

Brain-derived neurotrophic factor and antidepressant activity

Brain-derived neurotrophic factor (BDNF) is a member of the structurally and functionally homologous neurotrophin family. It is the most widely distributed trophic factor in the brain, and participates in neuronal growth, maintenance, and use-dependent plasticity mechanisms such as long-term potentiation and learning. There are several lines of evidence supporting a role for BDNF in the treatment of depression. This paper reviews the neurotrophin hypothesis of antidepressant action, and examines our current understanding of activity-dependent mechanisms of BDNF expression and function in limbic regions of the brain. Our discussion starts with the original observations of monoaminergic neurotransmitter dysfunction that served as the basis for early antidepressant drug development, and outlines evidence for neurodegeneration and functional deficits existing with chronic stress and depression. We continue with evidence that enhancement in neurotrophic support and associated augmentation in synaptic plasticity and function may form the basis for antidepressant efficacy, and serve as a current and future focus in the quest for more rapid-acting and effective medication treatments. Finally, we follow the current search for the intracellular mechanisms of antidepressant interventions that may bring the monoaminergic and neurotrophic hypotheses together, and help us to more fully understand the roles of both neurotransmitter and growth factor. Principal challenges to the neurotrophin hypothesis, and inconsistencies between clinical and preclinical research results, are also pointed out, as these also guide future experiments that will refine our understanding of treatment mechanisms.

Induction by E1A oncogene expression of cellular susceptibility to lysis by TNF

Tumour necrosis factor alpha (ref. 1), synthesized primarily by monocytes in response to various invasive agents, induces a wide variety of biological effects relevant to regulating cell growth and differentiation, including the selective killing of some tumour cells and the growth stimulation of some normal fibroblasts. As tumour necrosis factor (TNF) appears to kill tumour cells preferentially, we asked whether TNF sensitivity correlates with the expression of specific oncogene(s). If so, by examining the cellular target(s) of the oncogene product, it might be possible to identify specific factor(s) which mediate TNF action. By using an in vitro cytotoxicity assay with NIH 3T3 and Fisher BRK-derived cells expressing exogenously introduced oncogenes, we found that adenovirus E1A proteins induce susceptibility to TNF killing.

Visual and phonological pathways to the lexicon: evidence from Chinese readers

In this study, we investigated the role of visual and phonological information in lexical access of Chinese characters. Homophonic English words have been the main source of stimuli for word recognition research. However, since these stimuli also often look alike, visual and phonological information may be confounded in reported experiments. In contrast, many homophonic Chinese characters are visually distinct. In addition, visually similar characters often have very different pronunciations. These characteristics allow a more controlled investigation of the roles of visual and phonological information in activation of meaning. In the present study, two types of Chinese characters were used in a semantic categorization paradigm: integrated characters, which contain strokes that are not separable; and compound characters, which contain at least two clearly identifiable components. The results show that the recognition of a Chinese integrated character depends primarily on visual information, whereas the recognition of a Chinese compound character relies on visual, phonological, and semantic information. It is concluded that visual information plays a greater role in Chinese character recognition than has previously been documented.

ATM-dependent phosphorylation of human Rad9 is required for ionizing radiation-induced checkpoint activation

ATM (ataxia-telangiectasia-mutated) is a Ser/Thr kinase involved in cell cycle checkpoints and DNA repair. Human Rad9 (hRad9) is the homologue of Schizosaccharomyces pombe Rad9 protein that plays a critical role in cell cycle checkpoint control. To examine the potential signaling pathway linking ATM and hRad9, we investigated the modification of hRad9 in response to DNA damage. Here we show that hRad9 protein is constitutively phosphorylated in undamaged cells and undergoes hyperphosphorylation upon treatment with ionizing radiation (IR), ultraviolet light (UV), and hydroxyurea (HU). Interestingly, hyperphosphorylation of hRad9 induced by IR is dependent on ATM. Ser(272) of hRad9 is phosphorylated directly by ATM in vitro. Furthermore, hRad9 is phosphorylated on Ser(272) in response to IR in vivo, and this modification is delayed in ATM-deficient cells. Expression of hRad9 S272A mutant protein in human lung fibroblast VA13 cells disturbs IR-induced G(1)/S checkpoint activation and increased cellular sensitivity to IR. Together, our results suggest that the ATM-mediated phosphorylation of hRad9 is required for IR-induced checkpoint activation.

The influence of specific noradrenergic and serotonergic lesions on the expression of hippocampal brain-derived neurotrophic factor transcripts following voluntary physical activity

Previous studies have shown that hippocampal brain-derived neurotrophic factor (BDNF) mRNA levels are significantly increased in rats allowed free access to exercise wheels and/or administered antidepressant medications. Enhancement of BDNF may be crucial for the clinical effect of antidepressant interventions. Since increased function of the noradrenergic and/or serotonergic systems is thought to be an important initial mechanism of antidepressant medications, we sought to test the hypothesis that noradrenergic or serotonergic function is essential for the increased BDNF transcription occurring with exercise. In addition, individual transcript variants of BDNF were examined, as evidence exists they are differentially regulated by discrete interventions, and are expressed in distinct sub-regions of the hippocampus. The neurotransmitter system-specific neurotoxins p-chloroamphetamine (serotonergic) and N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (noradrenergic) were administered to rats prior to commencing voluntary wheel-running activity. In situ hybridization experiments revealed an absence of exercise-induced full-length BDNF mRNA elevations in the hippocampi of noradrenergic-lesioned rats. In addition, the striking elevation of the exon I transcript in the dentate gyrus was removed with this noradrenergic lesion. In contrast, other transcript variants (exons II and III) were elevated in several hippocampal regions as a result of this lesion. In serotonin-lesioned rats, the significant increases in full-length BDNF, exon I and exon II mRNA levels were sustained without alteration (with the exception of exon IV in the cornus ammonis subregion 4, CA4). Overall, these results indicate that an intact noradrenergic system may be crucial for the observed ability of exercise to enhance full-length and exon I hippocampal BDNF mRNA expression. In addition, these results suggest that the promoter linked to exon I may provide a major regulatory point for BDNF mRNA expression in the dentate gyrus. Elevations of other exons, such as II and III, may require the activation of separate neurotransmitter systems and intracellular pathways.

Human platelet factor 4 monomer-dimer-tetramer equilibria investigated by 1H NMR spectroscopy

As a function of protein concentration, proton NMR spectra of human platelet factor 4 (PF4) differ. Correlation with low-angle laser light scattering data has allowed identification of concentration-dependent NMR spectral changes to PF4 aggregation, with tetramers being the largest aggregates formed. Well-resolved aromatic ring proton NMR resonances were assigned to Tyr-60, His-I, and His-II in monomer, dimer, and tetramer states. Since Tyr-60 3.5 ring proton resonances are well resolved from state to state, estimation of fractional populations in each state was possible. By varying the PF4 concentration, changes in these populations when plotted according to the Hill equation show a bimolecular mechanism of aggregation which proceeds from monomers to tetramers through a dimer intermediate. Equilibrium constants for dimer association (KD) and tetramer association (KT) have been estimated as a function of pH and ionic strength. At pH 4, where KD and KT approach the same value, resonances associated with all three aggregate states are observed. Lowering the pH shifts the equilibrium to the monomer state, while raising the pH shifts the equilibrium to dimer and tetramer states. Analysis of the pH dependence of KD and KT suggests that electrostatic interactions, probably arising from Glu/Asp and Lys/Arg side chains, play a role in the binding process. Increasing the solvent ionic strength stabilizes the tetramer state especially at low pH, suggesting that intersubunit, repulsive electrostatic interactions probably between/among cationic side chains (Lys/Arg) attenuate the aggregation process. Information based primarily on histidine pKa values and photo-CIDNP 1H NMR data suggests that Tyr-60 and His-I, but not His-II, are significantly affected by the aggregation process.

A novel fermentation pathway in an Escherichia coli mutant producing succinic acid, acetic acid, and ethanol

Escherichia coli strain NZN111, which is unable to grow fermentatively because of insertional inactivation of the genes encoding pyruvate: formate lyase and the fermentative lactate dehydrogenase, gave rise spontaneously to a chromosomal mutation that restored its ability to ferment glucose. The mutant strain, named AFP111, fermented glucose more slowly than did its wild-type ancestor, strain W1485, and generated a very different spectrum of products. AFP111 produced succinic acid, acetic acid, and ethanol in proportions of approx 2:1:1. Calculations of carbon and electron balances accounted fully for the observed products; 1 mol of glucose was converted to 1 mol of succinic acid and 0.5 mol each of acetic acid and ethanol. The data support the emergence in E. coli of a novel succinic acid:acetic acid:ethanol fermentation pathway.

Lactobacillus kefiranofaciens M1 isolated from milk kefir grains ameliorates experimental colitis in vitro and in vivo

Lactobacillus kefiranofaciens M1, isolated from and identified in Taiwanese milk kefir grain, has demonstrated immune-modulating activity. In the present study, we further investigated the effects of Lb. kefiranofaciens M1 on intestinal epithelial cells in vitro and on dextran sodium sulfate (DSS)-induced colitis in vivo. The possible mechanisms regarding the cytokine products and intestinal epithelial barrier restoration as well as the putative receptor for the protective effects of Lb. kefiranofaciens M1 were investigated. In vitro results indicated that Lb. kefiranofaciens M1 could strengthen the epithelial barrier function in vitro by increasing the transepithelial electrical resistance (TEER) and significantly upregulated the level of the chemokine CCL-20 at both the apical and basolateral sites. The in vivo effects of Lb. kefiranofaciens M1 on the regulation of intestinal physiology indicate that this strain could ameliorate DSS-induced colitis with a significant attenuation of the bleeding score and colon length shortening. Production of proinflammatory cytokines was decreased and that of the antiinflammatory cytokine IL-10 was increased in the DSS-treated mice given Lb. kefiranofaciens M1. The putative receptor for the protective effects of Lb. kefiranofaciens M1 was toll-like receptor 2 (TLR2), which was involved in probiotic-induced cytokine production in vitro and in attenuation of the bleeding score and colon length shortening in vivo. In this study, the kefir lactobacillus Lb. kefiranofaciens M1 clearly demonstrated an anticolitis effect. Based on these results, Lb. kefiranofaciens M1 has the potential to be applied in fermented dairy products as an alternative therapy for intestinal disorders.

Effects of operating conditions on the adhesive strength of Pseudomonas fluorescens biofilms in tubes

Understanding the mechanical properties of biofilms, especially the force required to disrupt them and remove them from substrata is very important to development of antibiofouling strategies. In this work, a novel micromanipulation technique with a specially designed T-shaped probe has been developed to serve as an experimental means to measure directly the adhesive strength of biofouling deposits on the surface of a glass test stud. The basic principle of this novel technique is to pull away a whole biofilm accumulated on the surface of a glass test stud with T-shaped probe, and to measure simultaneously the force imposed on the biofilm. The adhesive strength between the biofilms and the surface to which they are attached, is defined as the work per unit area required to remove the biofilms from the surface. The biofouling experiments were performed on an elaborate design of a simulated heat exchanger system. A monoculture of Pseudomonas fluorescens was chosen as the fouling microorganism for the laboratory studies. Results indicate that the adhesive strength of the biofilm was affected by the conditions of operation, such as biofilm age, nutrient concentration, suspended cell concentration, pH, surface roughness of the substratum and fluid velocity. As noted, the effect of fluid velocity on the biofilm adhesive strength seemed to overwhelm other factors. At the same operating conditions, the biofilm adhesive strength increased as the fluid velocity increased within the range of 0.6-1.6m/s. In addition, the flow-related biofilm structures were observed that biofilms generally grew as a more compact pattern at the higher fluid velocity. Apparently, the fluid velocity can affect the biofilm structure, which in turn determines the biofilm adhesive strength. The knowledge of the biofilm adhesive strength with associated influences of the operating conditions may be used to define better cleaning procedures.

In vivo gene therapy for colon cancer using adenovirus-mediated, transfer of the fusion gene cytosine deaminase and uracil phosphoribosyltransferase

Virus-directed enzyme prodrug therapy (VDEPT) utilising cytosine deaminase (CD) converts 5-fluorocytosine (5-FC) into the chemotherapy agent, 5-fluorouracil (5-FU), and has entered into a clinical trial for metastatic colon cancer. To improve this system, a replication-deficient adenovirus, containing a bifunctional fusion gene, CD:uracil phosphoribosyltransferase (UPRT), was constructed (AdCDUPRT). UPRT enhances the conversion of 5-FU into its active metabolites, which inhibit DNA and RNA synthesis. In vitro, AdCDUPRT infection of colon cancer cells resulted in a marked increase in sensitisation to 5-FU, compared with AdCD-infected or uninfected cells. The corollary is a approximately 100-fold and approximately 10 000-fold increase in sensitisation to 5-FC in AdCDUPRT-infected cells, compared to AdCD-infected and uninfected cells, respectively. There was a strong bystander effect in vitro, 70% of tumour cells were killed by 5-FC when only 10% of cells expressed CDUPRT. In vivo, athymic mice with colon cancer xenografts treated with intratumoral AdCDUPRT and intraperitoneal 5-FC, significantly reduced tumour growth rates compared with untreated controls (P = 0.02), whereas AdCD/5-FC treated mice did not. At higher AdCDUPRT virus doses, 5-FC and 5-FU were equally effective at delaying tumour growth compared with controls. In summary, VDEPT for colon cancer utilising AdCDUPRT is more effective than AdCD and the bifunctional CDUPRT gene enables the use of either 5-FC or 5-FU as prodrugs.

Carbohydrate utilization by tilapia (Oreochromis niloticus x O. aureus) as influenced by different chromium sources

An experiment was conducted to study the influence of three different forms of chromium (CrCl3.6H2O, Na2CrO4.4H2O and Cr2O3) on the utilization of two carbohydrates (glucose and cornstarch) by juvenile hybrid tilapia (Oreochromis niloticus x O. aureus). Average initial body weight of the fish was 1.13 +/- 0.02 g. Fish were fed 5% body wt/d. Significantly (P < 0.05) greater body weight gain, food intake, protein retention, energy retention and body lipid concentration were observed in fish fed the starch diet than in those fed the glucose diet. Fish fed the glucose diet supplemented with any type of chromium had significantly greater weight gain than those fed the glucose diet without chromium supplementation. Fish fed the glucose diet supplemented with Cr2O3 had greater weight gain, food intake, protein retention, energy retention and body lipid concentration than those fed the unsupplemented glucose diet or the glucose diet supplemented with CrCl3.6H2O or Na2CrO4.4H2O. Delayed plasma glucose peak time was observed in tilapia fed the glucose diet supplemented with any type of chromium. Chromium supplementation generally lowered the glucose-6-phosphatase activity in tilapia. Phosphofructokinase activity was significantly higher in fish fed the glucose diet supplemented with Cr2O3 than in the other glucose-fed groups. These data suggest that chromium supplementation improved glucose utilization by tilapia and that Cr2O3 supplementation was markedly more effective than other chromium forms.

Intronless human dihydrofolate reductase genes are derived from processed RNA molecules

Three groups of recombinant bacteriophage containing coding sequences for dihydrofolate reductase (DHFR; tetrahydrofolate dehydrogenase; 5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase, EC 1.5.1.3) were isolated from two human DNA clone libraries. One recombinant (lambda hDHFR-1) contains three exons that encode the COOH-terminal portion of human DHFR. The other two human DHFR genes (hDHFR-psi 1 and hDHRF-psi 2) lack introns. hDHFR-psi 2 contains several in-phase termination codons and is only 93% homologous to the normal human DHFR coding sequences, whereas hDHFR-psi 1 has an open reading frame and is virtually identical to the coding sequence of the normal DHFR gene. The region of DNA sequence homology between each intronless gene and the normal DHFR gene extends 2.9 kilobases beyond the end of the coding sequences. At the 3' end of this homologous sequence, each intronless gene has an A-rich tract. The lack of introns and the presence of the 3' A-rich tract suggest that hDHFR-psi 1 and hDHFR-psi 2 were derived from processed RNA molecules. A short DNA sequence, 60 nucleotides 5' to the ATG start codon in lambda hDHFR-psi 2, is directly repeated immediately after the 3' A-rich tract; such terminal direct repeats also flank integrated proretroviruses and transposable DNA elements and are thought to be the hallmark of inserted DNA sequences.

A prospective randomized study comparing volume-standardized modified and conventional ultrafiltration in pediatric cardiac surgery

BACKGROUND

Modified ultrafiltration has been touted as superior to conventional ultrafiltration for attenuating the consequences of hemodilution after cardiac surgery with cardiopulmonary bypass in children. We conducted a prospective randomized study to test the hypothesis that modified and conventional ultrafiltration have similar clinical effects when a standardized volume of fluid is removed.

METHODS

From October 1998 to September 1999, 110 children weighing 15 kg or less (median weight 6.1 kg, median age 6.3 months) undergoing surgery with cardiopulmonary bypass for functionally biventricular congenital heart disease were randomized to conventional (n = 67) or arteriovenous modified ultrafiltration (n = 43) for hemoconcentration. The volume of fluid removed with both methods was standardized as a percentage of effective fluid balance (the sum of prime volume and volume added during cardiopulmonary bypass minus urine output): in patients weighing less than 10 kg, 50% of effective fluid balance was removed, whereas 60% was removed in patients weighing 10 to 15 kg. Hematocrit, hemodynamics, ventricular function, transfusion of blood products, and postoperative resource use were compared between groups.

RESULTS

There were no significant differences between groups in age, weight, or duration of cardiopulmonary bypass. The total volume of fluid added in the prime and during bypass was greater in patients undergoing conventional ultrafiltration than in those receiving modified ultrafiltration (205 +/- 123 vs 162 +/- 74 mL/kg; P =.05), although the difference was due primarily to a greater indexed priming volume in patients having conventional ultrafiltration. There was no difference in the percentage of effective fluid balance that was removed in the 2 groups. Accordingly, the volume of ultrafiltrate was greater in patients receiving conventional than modified ultrafiltration (95 +/- 63 vs 68 +/- 28 mL/kg; P =.01). Preoperative and postoperative hematocrit levels were 35.6% +/- 6.6% and 36.3% +/- 5.6% in patients having conventional ultrafiltration and 34.4% +/- 6.7% and 38.7% +/- 7.5% in those having modified ultrafiltration. By repeated-measures analysis of variance, patients receiving modified and conventional ultrafiltration did not differ with respect to hematocrit value (P =.87), mean arterial pressure (P =.85), heart rate (P =.43), or left ventricular shortening fraction (P =.21) from baseline to the postbypass measurements. There were no differences between groups in duration of mechanical ventilation, stay in the intensive care unit, or hospitalization.

CONCLUSIONS

When a standardized volume of fluid is removed, hematocrit, hemodynamics, ventricular function, requirement for blood products, and postoperative resource use do not differ between pediatric patients receiving conventional and modified ultrafiltration for hemoconcentration after cardiac surgery.

Comparative evaluation of two density gradient preparations for sperm separation for medically assisted conception

To evaluate and optimize the sperm separation efficiency of a novel silane-coated silica bead (Puresperm), serial studies were carried out to compare the various sperm parameters between: (i) three-layer (90%-70%-40%) Puresperm and three-layer (90%-70%-40%) conventional polyvinylpyrrolidone (PVP)-coated silica bead (Percoll) gradients; (ii) three-layer (90%-70%-40%) and two-layer (90%-45%) Puresperm gradients and separately the same for Percoll; and (iii) large (3.0 ml) and small (0.75 ml) semen loading volumes on three-layer Puresperm gradients. Normozoospermic semen samples were treated and analysed in 12 replicates for each experiment. Manual evaluation of concentration, percentage motility, percentage vitality, percentage normal morphology; computer-assisted semen analysis evaluation of concentration, percentage motility, grade of motility, motion characteristics (curvilinear velocity, linearity, amplitude of lateral head velocity, beat cross frequency, percentage hyperactivation); and yields from the initial semen samples were compared. Percoll was found to be superior to Puresperm in concentration, percentage motility, percentage vitality and yields after three-layer density gradient centrifugation. There were no significant differences in sperm parameters between two- and three-layer Percoll gradients, but three-layer Puresperm gradients behaved significantly better than two-layer gradients. Large semen volume loads on three-layer Puresperm gradients resulted in greater sperm concentrations, percentage motility, percentage vitality and percentage normal morphology, but small semen volume loads produced greater yields of good-quality spermatozoa. In the light of Percoll being withdrawn from the shelf for the use of assisted reproduction because of the presence of PVP, three-layer Puresperm gradients with large semen loading volumes appear to be an attractive alternative for sperm separation in medically assisted conception.

Action of dexmedetomidine on rat locus coeruleus neurones: intracellular recording in vitro

The action of dexmedetomidine on rat locus coeruleus neurones was examined using intracellular recordings from the in vitro brain slice preparation. Concentrations of dexmedetomidine from 1 to 1000 nM were tested. At 30 nM, dexmedetomidine produced complete inhibition of firing of all neurones tested (n = 21); this was associated with a 13 mV hyperpolarization (range 2.2-29.7 mV, n = 21) and a 27% reduction in input resistance (range 11.1-46.2%, n = 17). The dexmedetomidine responses reached a plateau phase between 100 and 1000 nM. Based on single-cell recordings, the hyperpolarizing potency of dexmedetomidine was found to be 6 times greater than that of clonidine (n = 10). The reversal potential for the dexmedetomidine-induced hyperpolarization was -106.9 +/- 1.7 mV (n = 9), a value similar to the K+ equilibrium potential; hyperpolarization was blocked by both CsCl and BaCl2. The effect of dexmedetomidine was antagonized by yohimbine, with a dissociation equilibrium constant of 30 nM. In contrast, prazosin, the alpha 1-, alpha 2B- and alpha 2C-adrenoceptor subtype-preferring ligand, did not inhibit the dexmedetomidine effect. Our results also show that low concentrations of oxymetazoline (10-300 nM), an alpha 2A-adrenoceptor subtype-selective drug, cause profound inhibition of neuronal activity in the locus coeruleus. These data therefore suggest that dexmedetomidine binds to alpha 2A-adrenoceptors on the cell membrane of neurones of the locus coeruleus and that this leads to opening of the inwardly rectifying K+ channels, resulting in the observed hyperpolarization of the membrane.

Identification of yeasts and evaluation of their distribution in Taiwanese Kefir and Viili starters

The objective of the present study was to investigate yeast communities in kefir grains and viili starters in Taiwan through conventional microbiological cultivation and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The DNA sequencing was used as a validity technique to ensure that all isolates within each group belonged to just one species, and to confirm the identified results of PCR-DGGE. Results indicated that a combination of conventional microbiological cultivation with PCR-DGGE and sequencing could successfully identify 4 yeast species from both types of cultures in Taiwan. Kluyveromyces marxianus, Saccharomyces turicensis, and Pichia fermentans were found in Taiwanese kefir grains with a distribution of 76, 22, and 2%, respectively, whereas Klu. marxianus, Saccharomyces unisporus and P. fermentans were identified in viili starters corresponding to 58, 11, and 31% of the total cell counts, respectively. Furthermore, the culture-independent method was applied to identify the yeast species using DGGE. Only 2 yeast species, Klu. marxianus and S. turicensis, were found in kefir grains and 2, Klu. marxianus and P. fermentans, in viili starters. These results suggest that in samples containing multiple species, PCR-DGGE may fail to detect some species. Sequences of yeast isolates reported in this study have been deposited in the GenBank database under accession nos. DQ139802, AF398485, DQ377652, and AY007920.

Vascular effects on ciliary tissue from endoscopic versus trans-scleral cyclophotocoagulation

AIM

To determine the acute and chronic vascular effects of endoscopic cyclophotocoagulation (ECP) versus trans-scleral cyclophotocoagulation (TCP) in a rabbit model.

METHODS

20 rabbits underwent ECP in one eye and another 20 rabbits had unilateral TCP. Five treated eyes from each group underwent endoscopic fluorescein angiography (EFA) of the treated ciliary processes at each of the following time points: immediate, 1 day, 1 week, and 1 month. Five untreated rabbits were used as controls. The NIH Image software program was used to trace ciliary processes in order to determine their mean intensity, as a measure of their perfusion. Histopathology was also performed on eyes from each time point.

RESULTS

Immediately and 1 day after laser, both TCP and ECP eyes demonstrated severely reduced or non-existent blood flow in the areas of treatment. TCP treated processes essentially remained non-perfused at the 1 week and 1 month time points. ECP treated processes showed some reperfusion at 1 week and greater reperfusion by 1 month. Histopathology confirmed the overall greater vascular occlusion seen with TCP.

CONCLUSIONS

Chronic poor perfusion of the ciliary body after TCP may account, in part, for its efficacy, as well as the significant complications including hypotony and phthisis. Late reperfusion of this region after ECP may provide some insight into the differences in efficacy and complication rates compared to TCP.

Methylphenidate treatment following ablation-induced hemiplegia in rat: experience during drug action alters effects on recovery of function

Two experiments examined the effects of single or multiple administrations of methylphenidate (MPH; Ritalin) and differing amounts of beam-walking trials (symptom relevant experience) during the period of drug action on recovery from hemiplegia following unilateral sensorimotor cortex ablation in rat. The first study tested multiple doses of MPH (10 mg/kg) or sterile saline given once daily, followed by four beam-walk (BW) trials at 1, 2, 3, and 6 h on 3 consecutive days. A significant and enduring enhancement of recovery was only observed 24 h after the third administration of MPH, compared to saline controls. In the second study, a single dose of MPH (10 mg/kg) or saline was administered 24 h after ablation, followed by 12 BW trials beginning 1 h and continuing at 15-min intervals until 3 h after MPH or saline administration. A significant and enduring facilitation of BW ability was produced by this single MPH treatment regimen. These data further support the importance of an interaction between symptom-relevant experience and drugs that increase norepinephrine transmission to enhance functional recovery after brain damage.