Lidocaine inhibition of inducible nitric oxide synthase and cationic amino acid transporter-2 transcription in activated murine macrophages may involve voltage-sensitive Na+ channel

Lidocaine has been reported to inhibit nitric oxide (NO) production in activated murine macrophages, but the role of inducible NO synthase (iNOS) in lidocaine-induced inhibition of NO has not been explored. In addition, type-2 cationic amino acid transporter (CAT-2) and guanosine triphosphate cyclohydrolase I (GTPCH) also regulate iNOS activity. The effects of lidocaine on CAT-2 and GTPCH are unknown. To explore further these effects, confluent immortalized murine macrophages (RAW264.7 cells) were incubated with lipopolysaccharide (LPS) or in combination with lidocaine (5, 50, or 500 microM) for 18 h before harvesting. We also used tetrodotoxin (TTX) and veratridine to elucidate the possible role of voltage-sensitive Na+ channel. Our data demonstrated that LPS significantly upregulated transcription of iNOS and CAT-2 but not GTPCH in stimulated macrophages. In a dose-dependent manner, lidocaine significantly attenuated the LPS-induced upregulation of iNOS and CAT-2. Conversely, lidocaine significantly increased GTPCH transcription in LPS-stimulated macrophages. The effects of TTX on iNOS, CAT-2, and GTPCH expression were comparable to those of lidocaine. In addition, veratridine significantly attenuated the effects of lidocaine and TTX. We therefore concluded that lidocaine significantly inhibits iNOS and CAT-2 and, in turn, enhances GTPCH transcription in LPS-stimulated macrophages via a mechanism that possibly involves the voltage-sensitive Na+ channel.

Pre-treatment of acupuncture stimulation of ST36 (Zusanli) significantly attenuates CAT-2, CAT-2B and GTPCH transcription in septic rat lungs

BACKGROUND

The isozymes of type-2 cationic amino acid transporter (including CAT-2 and CAT-2B) and guanosine triphosphate cyclohydrolase I (GTPCH) constitute part of the down-stream regulatory pathways that regulate nitric oxide (NO) production mediated by inducible NO synthase (iNOS). We sought to evaluate the effects of acupuncture stimulation of ST36 (Zusanli) on the expression of CAT-2, CAT-2B, and GTPCH in lipopolysaccharide (LPS)-stimulated rat lungs.

METHODS

Sixty rats were randomized into 6 groups (n = 10 in each group): 1) LPS, 2) Normal saline (N/S), 3) LPS + ST36, 4) ST36, 5) LPS + Sham, and 6) Sham groups. Manual acupuncture stimulation of ST36 (designated as "ST36") or a "nonacupoint" (designated as "Sham") was performed in lightly immobilized rats for 30 minutes. Then, LPS injection was performed to induce the expressions of iNOS, CAT-2, CAT-2B, and GTPCH in rat lungs. Rats were sacrificed 6 hours after LPS injection and the expressions of these enzymes were assayed.

RESULTS

Reverse transcription and polymerase chain reaction (RT-PCR) data revealed that the expressions of iNOS, CAT-2, CAT-2B, and GTPCH in N/S-stimulated rat lungs were low. Exposure to LPS significantly induced the expressions of iNOS, CAT-2, CAT-2B, and GTPCH. In addition, the pre-treatment of ST36 acupuncture significantly attenuated the LPS-induced expressions of iNOS, CAT-2, CAT-2B, and GTPCH in stimulated rat lungs.

CONCLUSIONS

Pre-treatment of acupuncture stimulation of ST36 had significantly inhibitory effects on LPS-induced iNOS, CAT-2, CAT-2B, and GTPCH expressions in septic rat lungs.

Propofol significantly attenuates iNOS, CAT-2, and CAT-2B transcription in lipopolysaccharide-stimulated murine macrophages

BACKGROUND

Propofol significantly inhibits inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) biosynthesis in stimulated macrophages. L-arginine transport mediated by the isozymes of type-2 cationic amino acid transporter (including CAT-2 and CAT-2B) has been reported to play a crucial role in regulating iNOS activity. We sought to evaluate the effects of propofol on L-arginine transport and transcription of CAT-2 and CAT-2B.

METHODS

Confluent murine macrophages (RAW264.7 cells) were stimulated with lipopolysaccharide (LPS) to induce NO production, L-arginine transport and the transcriptions of iNOS, CAT-2, and CAT-2B. Propofol (25, 50, and 75 microM) was added to the cells 4 hours before, immediately after, or 4 hours after LPS administration. After reacting with LPS for 18 hours, cell cultures were harvested and assayed.

RESULTS

Propofol administered 4 hours before LPS had no significant effects on NO production, L-arginine transport, and the transcriptions of iNOS and CAT-2. To our surprise, NO production and iNOS transcription were significantly enhanced by 25 microM propofol administered immediately after LPS. NO production and iNOS transcription were not affected by 50 microM propofol but significantly inhibited by 75 microM propofol administered immediately after LPS. CAT-2 transcription and L-arginine transport were significantly inhibited by 50 and 75 microM but not 25 microM propofol administered immediately after LPS. When administered 4 hours after LPS, 75 but not 25 and 50 microM propofol significantly inhibited NO production, L-arginine transport, and the transcription of iNOS and CAT-2. In addition, CAT-2B transcription was significantly inhibited by propofol that was administered 4 hours before, immediately after, or 4 hours after LPS.

CONCLUSIONS

Propofol had significantly inhibitory effects on LPS-induced NO production, L-arginine transport, and the expressions of iNOS, CAT-2 and CAT-2B in stimulated murine macrophages in a dose-dependent manner. In addition, timing of administration also affected this regulatory effect of propofol.

Proteomic analysis of human meibomian gland secretions

BACKGROUND/AIM

Human tears contain hundreds of proteins that may exert a significant influence on tear film stability, ocular surface integrity, and visual function. The authors hypothesise that many of these proteins originate from the meibomian gland. This study's aim was to begin to develop the proteomic methodology to permit the testing of their hypothesis.

METHODS

Meibomian gland secretions were collected from the lower eyelids of adult volunteers and placed in a chloroform-methanol mixture. Samples were partitioned in a biphasic system and non-lipid phase materials were reduced, alkylated, and trypsin digested to obtain peptides for protein identification. This peptide mixture was separated by micro-capillary reverse phase chromatography and the effluent examined by nano-electrospray MS and data dependent MS/MS. SEQUEST software was used to identify proteins from the MS/MS spectra.

RESULTS

The methodological approach to date has permitted the identification of more than 90 proteins in human meibomian gland secretions. Proteins include the alpha2-macroglobulin receptor, IgA alpha chain, farnesoid X activated receptor, interferon regulatory factor 3, lacritin precursor, lactotransferrin, lipocalin 1, lysozyme C precursor, potential phospholipid transporting ATPase IK, seven transmembrane helix receptor (also termed somatostatin receptor type 4), testes development related NYD-SP21 (also termed high affinity IgE receptor beta subunit), and TrkC tyrosine kinase.

CONCLUSIONS

These findings indicate that the meibomian gland secretes a number of proteins into the tear film. It is quite possible that these proteins contribute to the dynamics of the tear film in both health and disease.

The Effect of DNA Repair Defects on Reproductive Performance in Nucleotide Excision Repair (NER) Mouse Models: An Epidemiological Approach

In this study, we used an epidemiological approach to analyze an animal database of DNA repair deficient mice on reproductive performance in five Nucleotide Excision Repair (NER) mutant mouse models on a C57BL/6 genetic background, namely CSA, CSB, XPA, XPC [models for the human DNA repair disorders Cockayne Syndrome (CS) and xeroderma pigmentosum (XP), respectively] and mHR23B (not associated with human disease). This approach allowed us to detect and quantify reproductive effects based on a relatively small number of matings. We measured and quantified the scale of the effect between factors that might influence reproductive performance (i.e. age at co-housing, seasons) and reproductive parameters (i.e. litter size and pairing-to-birth interval -'pbi'). Besides, we detected and quantified the differences in reproductive performance between wild type mice and heterozygous/homozygous NER mutant mice. From our analyses, we found impaired reproduction in heterozygous and homozygous knock out mice; in particular, reduced litter size and lengthened pbi was related to the NER mutation-mHR23B, in heterozygous couples, even if they were otherwise phenotypically normal. Heterozygous mHR23B couples produced a 6.6-fold lower number of mHR23B(-/-) pups than indicated by Mendelian expectation; other genetic deficiencies studied were not statistically significant from each other or wild type controls. We concluded that careful epidemiological evaluations by analysis of animal database could provide reliable information on reproductive performance and detect deviations that would remain unnoticed without this. Also, some managerial aspects of mouse breeding could be evaluated.

Prevalence and determinants of prehypertension status in the Taiwanese general population

OBJECTIVE

The purpose of this study was to determine the prevalence rate of prehypertension and to compare the differences in demographic factors, anthropometric measurements, lifestyles and metabolic profiles between normotensive and prehypertensive individuals.

DESIGN

Data were based on the Nutrition and Health Survey in Taiwan (NAHSIT), a cross-sectional survey that adopted a multi-stage, stratified clustering sampling scheme. The data collection period was from 1 January 1993 to 31 December 1996.

METHODS

This study was a secondary analysis of data previously collected. Data from 1039 men and 1186 women, aged 18-96 years, were analyzed.

RESULTS

Approximately 34% of Taiwanese adults had prehypertension. The prevalence rate of prehypertension was higher among men (36%) than women (32%). In univariable logistic analysis, sex, age group, age, waist-hip ratio (WHR) group, body mass index (BMI) group, waist circumference, blood sugar, triglyceride, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), cholesterol/HDL and smoking status were significantly associated with prehypertension status. Multivariable logistic regression revealed that age [odds ratio (OR) = 1.014, 95% confidence interval (CI) = 1.004-1.0249] and BMI (OR = 1.106, 95% CI = 1.051-1.165) were the determinants of prehypertension status in men. For women, age (OR = 1.033, 95% CI = 1.022-1.044), waist circumference (OR = 1.031, 95% CI = 1.012-1.051) and triglyceride (OR = 1.003, 95% CI = 1.000-1.005) were the determinants of prehypertension.

CONCLUSIONS

This study underscores the importance of general obesity and central obesity as risk factors for prehypertension in the Taiwanese adult population. These two indices of obesity have different impacts on men and women.

Psychometric Evaluation of the Chinese Version of the Pittsburgh Sleep Quality Index (CPSQI) in Primary Insomnia and Control Subjects

In order to effectively study the population experiencing insomnia, it is important to identify reliable and valid tools to measure sleep that can be administered in the home setting. The purpose of this study was to assess psychometric properties for the Chinese version of the Pittsburgh Sleep Quality Index (CPSQI) in community-dwelling adults with primary insomnia. The CPSQI had an overall reliability coefficient of 0.82 -0.83 for all subjects. "Subjective sleep quality" was the component most highly correlated with the global score. Overall, the CPSQI showed acceptable test-retest reliability over a 14- to 21-day interval with a coefficient of 0.85 for all subjects and 0.77 for primary insomniacs. The two contrasting groups had significantly different global and component scores. A CPSQI of greater than 5 yielded a sensitivity and specificity of 98 and 55% in primary insomniacs vs. controls. A CPSQI of greater than 6 resulted in a sensitivity and specificity of 90 and 67%. Results suggest that the CPSQI is a psychometrically sound measure of sleep quality and disturbance for patients with primary insomnia. It may not be an effective screening tool because of its low specificity, but it can be a sensitive, reliable, and valid outcome assessment tool for use in community-based studies of primary insomnia.

Inhibition of lipopolysaccharide-induced expression of inducible nitric oxide synthase by phenolic (3E)-4-(2-hydroxyphenyl)but-3-en-2-one in RAW 264.7 macrophages

The large amount of nitric oxide (NO) produced by inducible NO synthase (iNOS) contributes to cellular injury in inflammatory disease. In the present study, a novel synthetic compound (3E)-4-(2-hydroxyphenyl)but-3-en-2-one (HPB) was found to inhibit lipopolysaccharide (LPS)-induced NO generation, but not through the inhibition of iNOS activity, in RAW 264.7 macrophages. Administration of HPB into mice also inhibited the LPS-induced increase in serum nitrite/nitrate levels. To evaluate the underlying mechanisms of HPB inhibition of NO generation, the expression of the iNOS gene in RAW 264.7 macrophages was examined. HPB abolished the LPS-induced expression of iNOS protein, iNOS mRNA and iNOS promoter activity in a similar concentration-dependent manner. LPS-induced nuclear factor-kappaB (NF-kappaB) DNA binding and NF-kappaB-dependent reporter gene activity were both significantly inhibited by HPB. This effect was mediated through the inhibition of inhibitory factor-kappaBalpha (IkappaBalpha) phosphorylation and degradation, and of p65 nuclear translocation. HPB had no effect on the LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinases (MAPK), and c-Jun NH(2)-terminal kinase (JNK). However, HPB suppressed the LPS-induced intracellular reactive oxygen species (ROS) production. These results indicate that HPB down-regulates iNOS gene expression probably through the inhibition of LPS-induced intracellular ROS production, which has been implicated in the activation of NF-kappaB.

Catecholamines' enhancement of inducible nitric oxide synthase-induced nitric oxide biosynthesis involves CAT-1 and CAT-2A

Catecholamines enhance inducible nitric oxide synthase (iNOS) expression that results in nitric oxide (NO) overproduction in lipopolysaccharide (LPS)-stimulated macrophages. L-arginine transport mediated by cationic amino acid transporters (including CAT-1, CAT-2, CAT-2A, and CAT-2B) is crucial in regulating iNOS activity. We sought to assess the effects of catecholamines on L-arginine transport and CAT isozyme expression in stimulated macrophages. Confluent RAW264.7 cells were cultured with LPS with or without catecholamines (epinephrine or norepinephrine, 5 x 10(-6) M) for 18 h. NO production, L-arginine transport, and enzyme expression were determined. Our data revealed that LPS co-induced iNOS, CAT-2, and CAT-2B expression, whereas CAT-1 and CAT-2A expression remained unaffected. Significant increases in NO production and L-arginine transport (approximately eight-fold and three-fold increases, respectively) were found in activated macrophages. Catecholamines significantly enhanced NO production and L-arginine transport (approximately 30% and 20% increases, respectively) in activated macrophages. Catecholamines also enhanced the expression of iNOS, CAT-1, and CAT-2A but not CAT-2 or CAT-2B in LPS-stimulated macrophages. Furthermore, the enhancement effects of catecholamines were inhibited by either dexamethasone or propranolol. We provide the first evidence to indicate that L-arginine transport in activated macrophages could be enhanced by catecholamines. Furthermore, this catecholamine-enhanced L-arginine transport might involve CAT-1 and CAT-2A but not CAT-2 or CAT-2B.

Cognitive behavioural therapy for primary insomnia: a systematic review

AIM

This paper reports a systematic review of seven studies evaluating the efficacy of cognitive behavioural therapy (CBT) for persistent primary insomnia.

BACKGROUND

Insomnia is one of the most common health complaints reported in the primary care setting. Although non-pharmacological treatments such as the CBT have been suggested to be useful in combating the persistent insomnia, the efficacy and clinical utility of CBT for primary insomnia have yet to be determined.

METHOD

A systematic search of Ovid, MEDLINE, psychINFO, PsycARTICLES, CINAHL, and EMBASE databases of papers published between 1993 and 2004 was conducted, using the following medical subject headings or key words: insomnia, primary insomnia, psychophysiological insomnia, sleep maintenance disorders, sleep initiation disorders, non-pharmacological treatment, and cognitive behavioural therapy. A total of seven papers was included in the review.

FINDINGS

Stimulus control, sleep restriction, sleep hygiene education and cognitive restructuring were the main treatment components. Interventions were provided by psychiatrists except for one study, in which the CBT was delivered by nurses. Among beneficial outcomes, improvement of sleep efficacy, sleep onset latency and wake after sleep onset were the most frequently reported. In addition, participants significantly reduced sleep medication use. Some studies gave follow-up data which indicated that the CBT produced durable clinical changes in total sleep time and night-time wakefulness.

CONCLUSIONS

These randomized controlled trial studies demonstrated that CBT was superior to any single-component treatment such as stimulus control, relaxation training, educational programmes, or other control conditions. However, heterogeneity in patient assessment, CBT protocols, and outcome indicators made determination of the relative efficacy and clinical utility of the therapy difficult. Therefore, the standard components of CBT need to be clearly defined. In addition, a comprehensive assessment of patients is essential for future studies.

Biofeedback-assisted Relaxation Training for Essential Hypertension

The main purpose of this study was to develop a way to predict which persons with essential hypertension would benefit most from biofeedback-assisted relaxation (BFAR) training. Second, the authors evaluated the effect of BFAR on blood pressure (BP) reduction, which was measured in the clinic and outside the clinic using an ambulatory BP monitor. Fifty-four adults with stage 1 or 2 hypertension (78% taking BP medications) received 8 weeks of relaxation training coupled with thermal, electromyographic, and respiratory sinus arrhythmia biofeedback. Blood pressure was measured in the clinic and over 24 hours using an ambulatory BP monitor pretraining and posttraining. Systolic BP dropped from 135.0 +/- 9.8 mmHg pretraining to 132.2 +/- 10.5 mmHg posttraining (F = 6.139, P = .017). Diastolic BP dropped from 80.4 +/- 8.1 mmHg pretraining to 78.5 +/- 10.0 mmHg posttraining (F = 4.441, P = .041). Data from 37 participants with baseline BP of 130/85 mmHg or greater were used to develop a prediction model. Regression showed that those who were able to lower their SBP 5 mm Hg or more were (1) not taking antihypertensive medication, (2) had lowest starting finger temperature, (3) had the smallest standard deviation in daytime mean arterial pressure, and (4) the lowest score on the Multidimensional Health Locus of Control-internal scale. Since these types of persons are most likely to benefit from BFAR, they should be offered BFAR prior to starting hypertensive medications.

NF-kappaB inhibitors significantly attenuate the transcription of high affinity type-2 cationic amino acid transporter in LPS-stimulated rat kidney

BACKGROUND

Sepsis-induced renal failure is closely related to inducible nitric oxide synthase (iNOS) upregulation and nitric oxide (NO) overproduction. Trans-membrane L-arginine transportation mediated by type-2 cationic amino acid transporter (CAT-2) isozymes, including CAT-2, CAT-2A, and CAT-2B, is one of the crucial mechanisms that regulate NO biosynthesis by iNOS. We previously had shown that endotoxemia significantly upregulated renal CAT-2 and CAT-2B but not CAT-2A expression. This study was, thus, conducted to further explore the role of nuclear factor-kappaB (NF-kappaB) in regulating the expression of CAT-2 isozymes in lipopolysaccharide (LPS)-treated rat kidney.

METHODS

Adult male Sprague-Dawley rats were randomly given intra-peritoneal injections of normal saline (N/S), LPS, LPS plus NF-kappaB inhibitor pre-treatment (PDTC, dexamethasone, or salicylate), or an NF-kappaB inhibitor alone. The rats were sacrificed at 6 hours after LPS injection and enzyme expression and renal injury were examined.

RESULTS

Renal iNOS, CAT-2, and CAT-2B were significantly upregulated in LPS-stimulated rat kidney. NF-kappa B inhibitors significantly attenuated this upregulation induced by LPS and resultantly attenuated renal NO biosynthesis and renal injury induced by LPS. In contrast, renal CAT-2A expression was not affected by either LPS or NF-kappaB inhibitors.

CONCLUSIONS

LPS co-induces iNOS, CAT-2 and CAT-2B expression in LPS-stimulated rat kidney. Furthermore, inhibition of NF-kappaB significantly attenuates NO biosynthesis through inhibition of iNOS, CAT-2, and CAT-2B, and, in turn, significantly reduces endotoxemia-induced renal injury.

Pulmonary transcription of CAT-2 and CAT-2B but not CAT-1 and CAT-2A were upregulated in hemorrhagic shock rats

Hemorrhagic shock stimulates nitric oxide (NO) biosynthesis through upregulation of inducible NO synthase (iNOS) expression. Trans-membrane l-arginine transportation mediated by the isozymes of cationic amino acid transporters (e.g. CAT-1, CAT-2, CAT-2A, and CAT-2B) is one crucial regulatory mechanism that regulates iNOS activity. We sought to assess the effects of hemorrhage and resuscitation on the expression of these regulatory enzymes in hemorrhage-stimulated rat lungs. Twenty-four rats were randomized to a sham-instrumented group, a sustained shock group, a shock with blood resuscitation group, or a shock with normal saline resuscitation group. Hemorrhagic shock was induced by withdrawing blood to maintain MAP between 40 and 45mmHg for 60min. Resuscitation by infusing blood/saline mixtures (blood resuscitation group) or saline alone (saline resuscitation group) was then performed. At the end of the experiment (300min after hemorrhage began), rats were sacrificed and enzymes expression as well as pulmonary NO biosynthesis and lung injuries were assayed. Our data revealed that hemorrhage-induced pulmonary iNOS, CAT-2, and CAT-2B transcription which was associated with pulmonary NO overproduction and subsequent lung injury. Resuscitation significantly attenuated the hemorrhage-induced enzyme upregulation, pulmonary NO overproduction, and lung injury. Blood/saline mixtures were superior to saline as a resuscitation solution in treating hemorrhage-induced pulmonary NO overproduction and lung injury. Hemorrhage and/or resuscitation, however, did not affect the expression of pulmonary CAT-1 and CAT-2A. It is, therefore, concluded that the expression of pulmonary iNOS, CAT-2, and CAT-2B is inducible and that of CAT-1 and CAT-2A is constitutive in hemorrhagic shock rat lungs.

Successful detection and management of unexpected endotracheal tube kinking during neurosurgery--a case report

Kinking of endotracheal tube (ETT) is not an infrequent problem during general anesthesia. However, failure to secure free airway following airway obstruction due to kinking of endotracheal tube or other tube problems may lead to lethality instead of lifesaving. We describe a case of unexpected kinking of ETT intraorally while craniotomy was underway. The kink might result from over-bending of the softening tube in the oral cavity due to oral temperature and neck flexion. Early detection and immediate management of the ETT kinking may reduce the possibility of morbidity and mortality in anesthesia. It could be more difficult to carry out reintubation in such an awful situation when the operation was proceeding. In this case report we would like to highlight how to accurately and quickly diagnose and manage the ETT kinking intraorally while craniotomy was in process under anesthesia. Emphasis is also laid on the importance of properly positioning of the head and neck prior to any operation especially in craniotomy. Besides, the flexometallic (FM) or armoured endotracheal tubes may be good substitutes for the polyvinyl chloride (PVC) ones in preventing the ETT kinking during general anesthesia.

Comparison of blood pressure measurement consistency using tonometric and automated oscillometric instruments

To effectively evaluate treatments for hypertension, researchers and clinicians must be able to measure blood pressure (BP) in a valid and reliable way. The purpose of this study is to compare measurements made in the clinic using beat-to-beat radial BP tonometry, measurements made during 24 hours using an ambulatory BP monitor, and measurements made in the clinic using an automated oscillometric BP monitor. Fifty-seven adults with primary hypertension participated in this study, which used a repeated measures descriptive design. Clinic and ABPM daytime averages were compatible for both SBP and DBP. In contrast, clinic SBP was 7.56 mmHg higher than the beat-to-beat SBP; clinic DBP was 9.83 mmHg higher than the beat-to-beat DBP. These data suggest that automated clinic measurements may be used in place of daytime ambulatory BP measurements. We also estimate sample sizes for future studies based on characteristics of clinic BP.

Change in expression of the guanosine triphosphate cyclohydrolase I in LPS-stimulated rats is tissue specific

BACKGROUND

The synthesis of tetrahydrobiopterin (BH4), a necessary cofactor for inducible nitric oxide synthase (iNOS), has been reported to be controlled by guanosine triphosphate cyclohydrolase I (GTPCH). Previous studies have demonstrated that GTPCH was induced by bacterial toxin. However, in a study using lipopolysaccharide (LPS)-treated murine macrophages model, we found that GTPCH expression was in fact constitutive rather than inducible. To further elucidate the effects of endotoxemia on GTPCH expression, we therefore preformed this LPS-treated rodent endotoxemia study with special focus on lung, liver, and kidney.

METHODS

Rats randomly received either normal saline (N/S) or LPS injection. At five different time points (0, 1, 2, 3 and 4 h after LPS injection in LPS group and comparable time points in N/S group), four rats from each group were sacrificed. Snap frozen tissues were then analyzed using semi-quantitative RT-PCR to determine GTPCH mRNA concentrations.

RESULTS

GTPCH mRNA concentrations in lung and liver tissues were similar between groups. On the other hand, GTPCH mRNA concentrations in renal tissues were significantly higher in the LPS group as compared with the N/S group. Our data demonstrated that GTPCH expression in lung and liver tissues was constitutive rather than inducible, whereas renal GTPCH expression was induced by LPS in a time-dependent manner.

CONCLUSIONS

GTPCH expression is tissue specific. Different tissues react differently to endotoxemia in terms of GTPCH expression. Therefore, efforts aiming at modulating GTPCH expression to limit NO overproduction should adjust accordingly.

Hemodynamics and arterial properties in response to mental stress in individuals with mild hypertension

OBJECTIVE

The role of tonic sympathetic stimulation on the properties of large arteries is largely unknown. The purpose of this study was to determine the effect of mental stress on hemodynamics and arterial properties in mild hypertensives.

METHOD

Twenty-three subjects with mild hypertension and 19 age-matched normotensives were compared to examine changes in hemodynamics and central arterial wave reflection before, during, and after mental stress.

RESULTS

The results demonstrate an acute effect of mental stress on blood pressure, heart rate, and arterial compliance. The static component (MBP) and the pulsatile (PP) component of arterial pressure increased significantly during mental stress and returned to baseline within a few minutes. Mild hypertensives did not have an increased response to mental stress. For both groups, an increase in HR and a consequent rise in CO were responsible for the increase in BP in response to mental stress. Compared with baseline, both groups demonstrated a decrease in arterial compliance during stress. Mental stress did not induce a significant change in total peripheral vascular resistance nor did it affect central arterial wave reflection in both groups. Individuals with mild hypertension demonstrated higher PP (p <.001), lower arterial compliance (p <.01), and higher AI (p <.05) than those with normal BP.

CONCLUSIONS

Hemodynamic and arterial responses to mental stress in individuals with normal BP and mild hypertension were similar. Several parameters, however, were different in basal state. These differences (ie, higher PP, lower compliance, and higher AI in the mild hypertensive group) could be due to the chronic effect of sympathetic stimulation on central arteries.

Determinants of the White‐Coat Effect in Normotensives and Never‐Treated Mild Hypertensives

The prognostic significance of the white-coat effect (WCE) is unclear. Knowledge of the predictors of the WCE may help illuminate the clinical significance of this phenomenon. The purpose of this study was to (i) compare characteristics of subjects demonstrating a WCE, those not demonstrating a WCE, and those demonstrating a reverse WCE and (ii) determine clinical features that may influence the size of the WCE. Forty-one subjects with normotension or mild hypertension who had never been treated with antihypertensive medications were recruited for the study. All subjects underwent a battery of anthropometrical measurements and clinic blood pressure (BP) measurements. To calculate arterial compliance, impedance cardiography was used to measure resting stroke volume in each subject. All subjects performed a laboratory mental stress protocol to determine the size of the BP reactivity. Ambulatory blood pressure (ABP) profiles were studied in each subject with the use of an oscillometric ABP recorder. White-coat effect was determined by subtracting the awake period of the ambulatory systolic blood pressure (SBP) from the clinical SBP. Subjects were grouped according to the size of their WCE. Those who showed a WCE of 5 mmHg and above were assigned to the WCE group; those who showed a WCE of between -5 and 5 mmHg were assigned to the no white coat effect (NWCE) group; those who exhibited a WCE of -5 mmHg and lower were assigned to the reverse white-coat effect (RWCE) group. Subjects with a positive WCE had significantly higher body mass index (BMI) than those without a WCE and those with a RWCE. The WCE group had significantly higher clinic SBP and heart rate (HR) than the RWCE group. Arterial compliance was significantly lower in the WCE group as compared to the NWCE group and the RWCE group. The three groups had comparable ABP profiles. In terms of BP variability, the increase in SBP in response to mental stress did not differ among the three study groups nor did the 24-hour and awake BP variability. For the sample as a whole, clinic HR and clinic-ambulatory SBP difference were higher and arterial compliance were lower in women than in men. Furthermore, clinic SBP significantly correlated with the systolic WCE (r = 0.40, P = 0.009). When men and women were analyzed separately, the correlation between clinic SBP and the systolic WCE was significant in women (r = 0.63, P = 0.001) but not in men (P = 0.95). Multiple linear regression showed that sex (P = 0.013) and clinical SBP (P = 0.003) were the only two variables that significantly influenced the systolic WCE. These two variables together accounted for 29% of the variation in the systolic WCE. In conclusion sex and clinic BP are two major determinants of the WCE. The results of this study indicate that WCE is not related to higher stress reactivity or higher BP variability.

Effects of daily activities on ambulatory blood pressure during menstrual cycle in normotensive women

The purpose of this study was to determine whether (1) there is a menstrual phase effect on blood pressure (BP) and heart rate (HR), and (2) the effects of physical effort, posture, or moods on BP and HR is mediated by the menstrual phase. Twelve normotensive women, aged between 28 and 50, with normal menstrual cycles were studied. BP was measured at 30- to 60-min intervals during a 24-hr period using an ambulatory BP monitor on Days 1, 8, 15, and 22 of the menstrual cycle. Participants were asked to report their posture, physical effort, and mood ("annoyed," "tense," and "happy") on 5-point Likert-type scales each time the ambulatory BP monitor took measurements. Systolic BP (SBP) was lower on Day 8 of the cycle. Diastolic BP (DBP) and HR were lower on Days 1 and 8. Daytime SBP was affected by the time of the day and posture, but not by moods, whereas daytime DBP was affected by posture and levels of tenseness. The level of physical effort only affected HR, not BP. The average daytime physical and emotional variables had little influence over the average daytime BP. In 12 normotensive women with a normal menstrual cycle, SBP was lower during the follicular phase and DBP and HR were lower during the follicular phase and menstruation even after controlling the effects of other factors. Physical activity or moods had only momentary effects on BP or HR. A cross-validation statistical method used is suggested to study how individuals are affected by various factors. With the use of this method, the inclusion of menstrual phase in the model improved the prediction of SBP for 5 out of the 12 women studied.

White coat hypertension: understanding the concept and examining the significance

Because the concept of white coat hypertension is evolving, a variety of definitions appear in the literature. There has also been continuing debate as to whether white coat hypertension is a benign clinical condition or is associated with increased hypertensive complications. This paper summarizes and evaluates the literature on white coat effect/hypertension, with a focus on the following aspects of the concepts: (1) alternative definitions, (2) prevalence and predictors, (3) prognostic significance, and (4) implications for clinical practice. The evidence suggests that white coat hypertension is not a harmless phenomenon. It is frequently associated with increased target-organ damage and often coexists with other cardiovascular risk factors. The extent of the presence of other risk factors may determine the risks associated with white coat hypertension. It is important for clinicians to understand the concept, learn to diagnose it properly, and develop strategies for evaluating risk levels so that patients receive the proper treatment.

Premedication with low-dose oral midazolam reduces the incidence and severity of emergence agitation in pediatric patients following sevoflurane anesthesia

BACKGROUND

Sevoflurane is a volatile anesthetic agent with low pungency, non-irritating odor, and low blood/gas partition coefficient that makes it an attractive alternative to halothane. However, a high incidence of emergence agitation (EA) has been reported in pediatric patients after sevoflurane anesthesia. The underlying mechanism of sevoflurane-induced EA remains unclear. Rapid recovery of consciousness (emergence) from sevoflurane anesthesia has been proposed as one possible mechanism. We, therefore, hypothesized that sedatives such as midazolam may counteract sevoflurane's rapid emergence and thus reduce the incidence and the severity of sevoflurane-induced EA.

METHODS

A prospective, controlled, single-blinded study was carried out in 88 ASA class I or II pediatric patients scheduled for elective outpatient surgery. Patients were assigned to receive either midazolam (oral midazolam, 0.2 mg/kg as anesthetic premedication) or saline (oral normal saline as premedication) before the conduct of anesthesia. When separation from parents was due its process was watched and evaluated. Induction of anesthesia and maintenance of anesthesia were uniform in both groups. Induction of anesthesia was made possible with 8% sevoflurane and N2O in 50% O2. Intubation was performed straight without the aid of muscle relaxant and the ventilator was set to maintain normocapnia. Anesthesia was maintained with 3% sevoflurane and N2O in 50% O2 until the surgery was over. All matters of relevant time periods were recorded (induction, surgical procedure, extubation and transportation). In the post-anesthesia care unit (PACU), adverse events, the incidence and the severity of EA, analgesic requirement, duration of PACU stay, and parental as well as PACU nurses' satisfaction were evaluated.

RESULTS

A significant lower incidence and less severity of EA were noted in patients premedicated with midazolam. Less postoperaive analgesia was required in patients who had received midazolam. Although midazolam-premedicated patients remained sedated after sevoflurane anesthesia, the duration of the PACU stay was not significantly different from that of saline-treated patients. Both parents and PACU nurses were more satisfied with midazolam as premedication. No solid evidence showed that there was close correlation between the process of separation from parents and the occurrence of EA.

CONCLUSIONS

Premedication with oral midazolam is safe, convenient and effective in decreasing the occurrence of sevoflurane-induced EA. It does not delay discharge from PACU and is suitable for outpatient surgery.

Noninvasive measurements of central arterial pressure and distensibility by arterial applanation tonometry with a generalized transfer function: implications for nursing

Decreased distensibility of large arteries is a strong indicator of cardiovascular risk. Measurements of arterial distensibility can be made noninvasively with the use of an arterial applanation pressure tonometer with a generalized transfer function. This article reviews (1) the concept of arterial distensibility and its relation to pulse wave amplitude, velocity, and reflection; (2) epidemiologic evidence that large-artery stiffness increases cardiovascular risks; and (3) the estimation of arterial distensibility with the use of noninvasive techniques, with an emphasis on measuring pulse wave velocity and calculating the aortic augmentation index. Finally, it addresses the application of arterial applanation tonometry in nursing research and practice.

Testosterone and estrogen act via different pathways to inhibit puberty in the male Siberian hamster (Phodopus sungorus)

The peripubertal transition in male mammals is accompanied by a gradual decrease in sensitivity to the inhibitory effects exerted by gonadal hormones, such as T and E2. Here, we investigated the effects of chronic T and its metabolites, 5alpha-dihydrotestosterone and E2 on the hypothalamo-pituitary-gonadal axis at puberty. We also examined if T effects are distinct or mediated through its conversion to 5alpha-dihydrotestosterone or E2. Twenty-day-old male Siberian hamsters were sc implanted with a SILASTIC brand capsule containing varying doses of T, 5alpha-dihydrotestosterone, or E2. Several functional parameters of the hypothalamo-pituitary-gonadal axis were evaluated including hypothalamic GnRH concentration, pituitary and plasma FSH levels, pituitary FSH and LH mRNA, and testicular status. Our results showed that gonadal steroids inhibited puberty in a dose-dependent manner as evaluated by testes mass (undiluted steroid: T, 27 +/- 3 mg; 5alpha-dihydrotestosterone, 18 +/- 1 mg; and E2, 62 +/- 4 mg relative to cholesterol-implanted controls, 510 +/- 42 mg). Also, T decreased plasma FSH below detectable levels, but pituitary FSH concentration was unaffected (1.37 +/- 0.16 ng/microg protein) while E2-treated hamsters had normal plasma FSH levels (3.5 +/- 0.98 ng/ml) yet significantly lower pituitary FSH concentration (0.09 +/- 0.04 ng/microg protein). These results showed that the pathways of T and E2 action on the hypothalamo-pituitary-gonadal axis are distinct.

Intrathecal magnesium sulfate attenuates algogenic behavior and spinal amino acids release after kainic acid receptor activation in rats

Activation of N-methyl-D-asparate (NMDA) receptor and non-NMDA classes of glutamate receptors play a key role in spinal nociceptive processing. Using with a lumbar intrathecal (IT) catheter and a loop dialysis catheter in lightly anesthetized (1% isoflurane) rats, the effect of IT pre-treatment with magnesium sulfate (100, 300 or 500 microg) on IT kainic acid (KA: 1 microg; non-NMDA receptor agonist) evoked amino acids (AAs) release and corresponding behavior was examined. IT KA produced significant increases (mean+/-SD of % baseline concentration) in dialysate concentrations of aspartate (424+/-88%), glutamate (241+/-35%) and taurine (398+/-58%). IT pre-treatment with MgSO(4) resulted in a dose-dependent suppression of the evoked algogenic behavior and aspartate release. These data suggest that activation of spinal KA receptors provides a powerful stimulus for secondary spinal excitatory AAs release and corresponding appearance of pain behavior. The regulation of this release by magnesium suggests the possible role of this divalent cation in regulating this excitatory effect of non-NMDA receptor activation.

Effects on the bispectral index during elective caesarean section: a comparison of propofol and isoflurane

BACKGROUND

Awareness during general anesthesia has been a particular problem during caesarean section. About 7 percent of patients undergoing elective caesarean section have reported dreaming or recall of voices during the procedure. The bispectral index (BIS), a value derived from the electroencephalogram (EEG), has been shown to be useful in monitoring the depth of anesthesia. Supplementation of propofol or isoflurane for maintenance of anesthesia has been shown to effectively reduce the incidence of awareness. However, the effects of propofol or isoflurane on the BIS index have not been fully investigated. We therefore designed this study to compare the effects of isoflurane or propofol supplementation on the BIS index in 24 healthy parturients undergoing elective caesarean section.

METHODS

All patients had induction of anesthesia and orotracheal intubation in rapid sequence made possible by 1 MAC isoflurane with 50% N2O-50% O2 as conveyer and atracurium. After delivery, patients were randomly assigned to either of two groups (isoflurane or propofol). Patients in the Isoflurane group (n = 12) received 0.5 MAC isoflurane in 67% N2O-33% O2 and fentanyl + droperidol. Patients in the propofol group (n = 12) received propofol (8 mg/kg/h) infusion combined with 67% N2O-33% O2 and fentanyl + droperidol.

RESULTS

There was no difference between the two groups in total operation time, maternal blood loss, fetal Apgar scores. No differences between the two groups in heart rate, blood pressure or BIS index values were found throughout the surgery. No patient from either group reported recall of the operative procedure. However, 25% of patients (3 of 12) in the isoflurane group had poor uterine contraction, suggestive of doubtful appropriateness of the use of isoflurane for maintenance of anesthesia in delivery.

CONCLUSIONS

We therefore concluded that supplementation of isoflurane or propofol for maintenance of anesthesia can satisfactorily decrease the BIS index and minimize the incidence of awareness in patients undergoing caesarean section under general anesthesia. The BIS index is a reliable monitor of the hypnotic component of anesthesia.

Biological and immunological characterization of multiple GnRH in an opisthobranch mollusk, Aplysia californica

Gonadotropin-releasing hormone (GnRH) is a neurohormone central to the regulation of reproductive functions in vertebrates. Recently, several studies have reported the presence of GnRH immunoreactivity (IR) in a number of mollusks, suggesting that the distribution of GnRH may not be restricted to Phylum Chordata. In the present study, we extend our investigations to an opisthobranch mollusk, Aplysia californica, to characterize the source, chemical nature, and biological activity of molluscan GnRH-related molecules. Specific radioimmunoassays (RIAs) of various tissue extracts of Aplysia revealed that only ovotestis, hemocytes, and hemolymph contained significant amounts of GnRH that crossreacts with antisera raised against tunicate-I (tI) and mammalian (m) GnRH. Further RIAs and extractions revealed that the GnRH-IR in the hemolymph is biochemically and immunologically distinct from the GnRH-IR in the hemocytes and ovotestis. Using reverse-phase high-performance liquid chromatography coupled with RIAs, the GnRH-IR in the hemolymph was resolved into two major peaks. The first peak eluted earlier than most known forms of vertebrate GnRH, and the later peak coeluted with m, lamprey I, chicken II, and tI-GnRH. However, both peaks were broad and may contain a heterogeneous mixture of GnRH-IR. Immunocytochemical study showed that tI-GnRH-IR was present in the connective sheath surrounding the central nervous system, with a strong presence in what appeared to be vascular space, again suggesting the close association between Aplysia GnRH-IR and circulation. Finally, treatment of the neuroendocrine bag cells with chicken II GnRH significantly decreased the duration of the afterdischarge (AD, a characteristic pattern of electrical firing in bag cell neurons) and the number of action potentials fired during an AD, indicating the presence of a corresponding GnRH receptor in the Aplysia central nervous system. Overall, the results demonstrated the presence of multiple forms of GnRH-IR that crossreact with tI- and mGnRH antisera in A. californica and the ability of a vertebrate GnRH to alter Aplysia neural activity. Together, these data suggest that GnRH may be a factor released by the ovotestis and hemocytes into the circulation to alter neural functions. GnRH-IR produced by the latter may serve as a novel mediator of the neural and immune functions in Aplysia.

Role of the cAMP signaling pathway in the regulation of gonadotropin-releasing hormone secretion in GT1 cells

We studied the signaling pathways coupling gonadotropin-releasing hormone (GnRH) secretion to elevations in cAMP levels in the GT1 GnRH-secreting neuronal cell line. We hypothesized that increased cAMP could be acting directly by means of cyclic nucleotide-gated (CNG) cation channels or indirectly by means of activation of cAMP-dependent protein kinase (PKA). We showed that GT1 cells express the three CNG subunits present in olfactory neurons (CNG2, -4.3, and -5) and exhibit functional cAMP-gated cation channels. Activation of PKA does not appear to be necessary for the stimulation of GnRH release by increased levels of cAMP. In fact, pharmacological inhibition of PKA activity caused an increase in the basal secretion of GnRH. Consistent with this observation activation PKA inhibited adenylyl cyclase activity, presumably by inhibiting adenylyl cyclase V expressed in the cells. Therefore, the stimulation of GnRH release by elevations in cAMP appears to be the result of depolarization of the neurons initiated by increased cation conductance by cAMP-gated cation channels. Activation of PKA may constitute a negative-feedback mechanisms for lowering cAMP levels. We hypothesize that these mechanisms could result in oscillations in cAMP levels, providing a biochemical basis for timing the pulsatile release of GnRH.

Postoperative myocardial infarction in a patient with perioperative ST-depression--a case report

Often we ignore electrocardiogram (EKG) evidence of ischemia and no adverse events occur. However, once in a while these ischemic episodes will turn into a full-blown myocardial infarction. Therefore, studying perioperative events which tilt the balance over to postoperative myocardial infarction (PMI) can enlighten our knowledge in postoperative myocardial infarction (MI) prevention. We present a case of ST depression in perioperative EKG evolving into postoperative MI. In this paper we attempt to explore various possibilities which could have altered this patient from her ischemic state into an infracted event.

Retinal hamartoma in oral-facial-digital syndrome

Only recently have intraocular findings been described in oral-facial-digital syndrome (OFDS), including 5 cases of chorioretinal colobomas and 1 case of optic nerve coloboma. We report a case of a new ocular anomaly associated with this syndrome: a retinal hamartoma in a male infant with OFDS. The patient had bilateral retinal masses that were suspicious for retinoblastoma because of a family history of retinoblastoma. Physical examination and imaging studies of the retinal masses could not differentiate between retinoblastoma, hamartoma, or persistent hyperplastic primary vitreous. Subsequent pathologic study of an enucleated globe was diagnostic of a retinal hamartoma. This case further illustrates the heterogeneity of ocular anomalies in OFDS and underscores the importance of a complete ophthalmologic evaluation in patients with this syndrome.

Children with mucopolysaccharidoses--three cases report

The mucopolysaccharidoses (MPS) are a group of inherited disorders of metabolism, with widespread, progressive involvement and derangement of many organs and tissues. Because of their disabling nature, frequent surgical intervention for the abnormality entailed is common, and is associated with a high degree of anesthetic risks perioperatively. One of the major hazards which we find clinically is airway difficulty. Multiple factors are present in the mucopolysaccharidoses to make airway management and trachael intubation potentially hazardous. Aside from generalized infiltration and thickening of the soft tissues, the oropharynx may be obstructed by a large tongue with tonsillar hypertrophy. Also, the friable mucosa covering the nasal and oral pharynx renders these structures easily to bleed and edematous. The neck is typically short and immobile, and the cervical spine and tempromandibular joint may have a limited range of movement. From our experience, we have learned not to overlook the propensity of airway difficulty. The uniqueness of their anatomy and extremely sensitive airway often result in failed intubation and bronchospasm even after successful intubation. Recently, in Mackay Memorial Hospital we have encountered in series three pediatric cases with mucopolysaccharidoses (one Hurler and two Hunter syndromes). In this report we would like to share our experiences and to discuss the anesthetic risks and management of the MPS patients.

Lidocaine concentrations in plasma and cerebrospinal fluid after systemic bolus administration in humans

Preclinical studies suggest that systemic lidocaine acts at the level of the spinal dorsal horn to inhibit hyperalgesia resulting from nerve injury, yet no clinical data are available to support this view. Therefore, we sought to characterize the time course of lidocaine in the plasma and cerebrospinal fluid (CSF) after an IV bolus injection of lidocaine 2 mg/kg in patients scheduled for surgery involving spinal anesthesia. Sixty-five patients were randomly allocated to one of five study groups (n = 13 per group) receiving IV lidocaine before CSF/ plasma sampling at 5, 10, 15, 30, or 60 min. Gas chromatographic analysis of these samples revealed a fast but transient peak (5-15 min) in lidocaine plasma levels (1.7+/-0.16 microg/mL), which declined rapidly thereafter. Only small concentrations of IV lidocaine were found in the CSF (6%- 8% of plasma concentration), but this fraction remained stable from 15 min until termination of the experiment. No statistical correlation was observed between plasma and CSF lidocaine levels. These data suggest that because of the prolonged availability of lidocaine at the spinal dorsal horn level, systemic administration of lidocaine suppresses central sensitization within the spinal cord after nerve injury in humans.

IMPLICATIONS

Cerebrospinal fluid concentrations of lidocaine after its systemic bolus delivery in humans indicate that the spinal cord may be the major site of antinociceptive action by this route of drug administration.

The comparative potency of intravenous nicardipine and verapamil on the cardiovascular response to tracheal intubation

BACKGROUND

Two different types of calcium channel blockers (namely nicardipine and verapamil) have been used widely in clinical practice. However, no clinical studies have previously been performed to ascertain the relative potency of intravenous verapamil and nicardipine in the attenuation of cardiovascular response to tracheal intubation.

METHODS

We assessed the optimal dose and relative potency of verapamil and nicardipine in the attenuation of hemodynamic response to tracheal intubation in 135 healthy patients. Control group (Group D received normal saline i.v. Patients in Groups II-V received nicardipine 0.005, 0.01, 0.03 and 0.06 mg/kg i.v., respectively. Patients in Groups VI-IX received verapamil 0.03, 0.05, 0.1 and 0.15 mg/kg i.v., respectively. Anaesthesia was induced with propofol (2.5 mg/kg) and muscle relaxation was facilitated by vecuronium (0.2 mg/kg, i.v.). One min after induction, tracheal intubation was performed. Mean arterial pressure (MAP) was measured at 1 min interval from 10 min before induction to 15 min after induction.

RESULTS

The ED50 with 95% confidence interval of nicardipine and verapamil for the attenuation of 50% mean arterial pressure (MAP) increase after tracheal intubation were 14.55 micrograms/kg (8.25-25.67) and 75.4 micrograms/kg (58.7-96.95), respectively. The ED50 with 95% confidence interval of verapamil for the reduction of the 50% heart rate (HR) increase post tracheal intubation was 57.4 micrograms/kg (18-182.2). No differences were found in the frequency of perioperative arrhythmia, post-operative hypotension, postoperative emesis, dizziness, muscle weakness and muscle soreness within two hours following surgery, when compared control with experimental groups (p > 0.05).

CONCLUSIONS

These results suggest that verapamil and nicardipine attenuate the hypertensive response to tracheal intubation without significant adverse effects in healthy patients. The dose ratio (ED50 nicardipine and ED50 verapamil for MAP) with 95% confidence interval was revealed to be 2.3 (1.82-7.41).

Expression of Vitreoscilla hemoglobin is superior to horse heart myoglobin or yeast flavohemoglobin expression for enhancing Escherichia coli growth in a microaerobic bioreactor

Expression of a gene encoding hemoglobin (VHb) from the aerobic bacterium Vitreoscilla sp. in several organisms, including Escherichia coli, has been shown to improve microaerobic cell growth and enhance oxygen-dependent product formation. The suitability of VHb to enhance microaerobic metabolism has been suggested to depend on its unusual oxygen binding characteristics. To examine whether hemoproteins of other origins can also elicit the positive effects VHb exerts in microaerobic E. coli cells, we subcloned the genes encoding Vitreoscilla VHb, horse heart myoglobin (HMb), and yeast flavohemoglobin (YFb) behind the IPTG-inducible tac promoter on a medium-copy-number vector and transformed these globin-expression plasmids into E. coli MG1655 and DH5 alpha. Biologically active VHb, HMb, and YFb were produced from these constructions in E. coli as judged by their ability to abduct carbon monoxide. The presence of HMb increased the growth of wild-type cells during the early stages of fed-batch growth, but the final optical densities of HMb-expressing cultures were comparable with the wild-type control not synthesizing HMb. The presence of VHb increased the cell density by 70% under the same cultivation conditions. The expression of wild-type YFb reduced the final cell density by 30% relative to the non-globin-expressing control.

Regulation of gonadotropin-releasing hormone neurons by basic fibroblast growth factor

The development of a functional network of gonadotropin-releasing hormone (GnRH) neurons in the central nervous system requires a series of complex regulatory mechanisms, presumably mediated in part by neurotrophic factors. The difficulty in studying factors regulating the development of GnRH neurons stems from their paucity and scattered distribution in the brain; as a result, little was known about the role of neurotrophic factors in the development of the mature GnRH neuronal network. Recent utilization of immortalized GnRH neuronal cell lines (GT1) has enabled us to identify and study specific neurotrophic factors and their functions in vitro. The potent neurotrophic effect of basic fibroblast growth factor (bFGF) and the presence of a high abundance of receptors for bFGF in GT1 cells have led to the hypothesis that bFGF may be an important regulator of GnRH neuron expansion, survival, migration, and connectivity.

Basic fibroblast growth factor is a neurotropic factor in GT1 gonadotropin-releasing hormone neuronal cell lines

Basic fibroblast growth factor (bFGF) plays an important role in development of the central nervous system and is neurotropic for a variety of neurons. In this study, we investigated whether bFGF is neurotropic for GT1 GnRH neuronal cell lines and if these cells express functional FGF receptors (FGFRs). The GT1 cell lines generated by genetically targeted tumorigenesis display highly differentiated properties of GnRH neurons. Addition of 2 and 10 ng/ml bFGF increased neurite outgrowth of GT1-7 cells and resulted in a significant increase of GT1 cell survival in serum-free medium. However, bFGF had no effect on [3H]thymidine incorporation at 24 or 48 h. RNase protection assays using riboprobes specific for murine FGFRs 1-3 showed that GT1 cells express FGFRs 1 and 3 but not 2. Occupancy of FGFRs with 10 ng/ml bFGF stimulated the sustained tyrosine phosphorylation of both the 42- and 44-kilodalton mitogen-activated protein kinases (MAPKs) for up to 6 h as shown by Western blot analysis. In addition, phosphorylation of the MAPKs was associated with enzyme activation as shown by an in-gel MAPK assay. GT1-1 and GT1-7 cells also express messenger RNA for bFGF, although the level of bioactive bFGF synthesized by GT1 cells appears suboptimal because GT1 cells can further respond to exogenously added bFGF. Thus, we have demonstrated that bFGF is a neurotropic factor in GT1 GnRh neuronal cell lines, raising the possibility that bFGF may play a role in the neurobiology of GnRH neurons.

Fnr, a global transcriptional regulator of Escherichia coli, activates the Vitreoscilla hemoglobin (VHb) promoter and intracellular VHb expression increases cytochrome d promoter activity

The oxygen-regulated promoter (Pvhb) of the Vitreoscilla hemoglobin gene has been applied to direct high-level expression of several cloned proteins, including Vitreoscilla hemoglobin (VHb), which improves productivity of many aerobic processes. In an effort to gain a better understanding of the regulation of Pvhb, and to guide further optimization of this technology, we investigated whether the Escherichia coli global regulatory molecules Fnr and the Arc system (ArcA and ArcB), which control the expression of various genes under either aerobic or anaerobic conditions, also regulate Pvhb activity in E. coli. The activity of Pvhb and the expression of VHb in E. coli were activated by Fnr, but were relatively unaffected by the Arc system under microaerobic conditions (DO less than 2% air saturation). We also examined the possibility of VHb affecting cytochrome d promoter activity during microaerobiosis. The presence of VHb increased the activity of beta-galactosidase from a cytochrome d promoter-lacZ fusion by 1.5-fold. This indicates that VHb affects oxygen-regulated transcription of E. coli genes and may contribute to the modified physiology observed in VHb-expressing E. coli.

The nature and distribution of gonadotropin-releasing hormones in brains and plasma of ranid frogs

Highly specific antisera and reversed-phase HPLC were used to examine the nature and distribution of gonadotropin-releasing hormone (GnRH) in the brains and plasma of three species of Rana frog previously reported to vary in the types and brain distributions of GnRH. The three species examined, Rana pipiens, Rana esculenta, and Rana ridibunda, exhibit differences in total concentration and relative concentrations of GnRH in brain areas, but all three contain the mammalian and chicken-II forms of GnRH (mGnRH and cGnRH-II). Both forms were found in the telencephalon and diencephalon, but mGnRH is consistently the most abundant form in the preoptic-hypothalamic area (e.g., ratios of mGnRH:cGnRH-II > 3:1 in hypothalamus-median eminence), whereas, cGnRH-II is the most abundant in the telencephalon and the only form measured in the cerebellum and medulla. The total content of cGnRH-II in the whole brain is about 1.5-2 times higher than that of mGnRH, due to the larger size of the areas outside the preoptic-hypothalamic area. These general patterns were the same for adults and juveniles. We found no evidence of a third form of GnRH corresponding to salmon GnRH in hypothalamus or other brain areas of R. esculenta as previously reported. These analyses also revealed the presence of both forms of GnRH in plasma draining the hypothalamic area, but the concentration of cGnRH-II is relatively higher than that in the corresponding hypothalamic tissue, suggesting differentially greater release or slower degradation of this form. These results do not support the conclusion that the ranid frogs are highly variable in the nature and distribution of GnRH in the brain, although they suggest that both forms of GnRH are potentially involved in the direct regulation of pituitary gonadotropes.

Intracellular expression of Vitreoscilla hemoglobin alters Escherichia coli energy metabolism under oxygen-limited conditions

An earlier stoichiometric analysis of oxygen-limited metabolism of Escherichia coli expressing cloned Vitreoscilla hemoglobin (VHb) suggested improved efficiency of ATP production relative to wild-type controls [Khosla, C., Curtis, J. E., DeModena, J., Rinas, J. & Bailey, J. E. (1990) BioTechnol. 8, 849-853]. This hypothesis has been further examined by determining several energetic parameters of different VHb-expressing E. coli (VHb+) strains relative to controls not expressing VHb (VHb-). The H+/O ratio, the transmembrane delta pH, and the ATP content of VHb+ constructs are 1.5, 1.6 and 2 times, respectively, corresponding values in VHb- controls. VHb was expressed using a low-copy-number vector in E. coli mutant strains lacking cytochrome o, cytochrome d, or both terminal oxidases; significant growth enhancement due to VHb expression was observed only in the strain having functional cytochrome o and lacking cytochrome d. All of these data obtained using different E. coli strains are consistent with a model of VHb action that hypothesizes enhancement by VHb of activity of the lower oxygen-affinity, higher proton-pumping-efficiency cytochrome o terminal oxidase under oxygen-limited growth conditions.

Role of aromatization in testosterone-induced inhibition of luteinizing hormone secretion in female turtles, Trachemys scripta

Both 17 beta-estradiol (E2) and testosterone (T) were shown to inhibit in vitro pituitary LH secretion in the turtle Trachemys scripta. Since T was approximately 500 times less potent than E2, and 5 alpha-dihydrotestosterone was even less active than T, the inhibitory action of T may result from its aromatization to estrogen. We utilized both in vivo and in vitro approaches to elucidate the roles of T and estrogen in the negative feedback of pituitary LH secretion. Gonadectomy of adult (vitellogenic) females significantly elevated plasma LH. Adult females treated with fadrozole (an aromatase inhibitor) with or without daily injections of keoxifene (an antiestrogen) also showed an increase in plasma LH to a level comparable to that observed in gonadectomized females, whereas plasma LH levels of juvenile females treated with fadrozole remained undetectable. In vitro LH secretion in response to GnRH in juvenile females was significantly inhibited by 48-h exposure to 50 ng/ml T or 100 pg/ml E2. Both fadrozole (200 microM) and keoxifene (200 nM) significantly blocked this T-induced inhibition of LH secretion, demonstrating that T lacks intrinsic inhibitory activity. Confirmation of the inhibition of aromatase activity by fadrozole comes from metabolic studies of 1 beta-[3H]androstenedione using turtle brain, ovary, and pituitary. In vitro, fadrozole altered the metabolism of 1 beta-[3H]androstenedione and inhibited aromatase activities in these tissues. These results indicate that the inhibitory effect of T is largely mediated through its aromatization to estrogen, and that estrogen is primarily responsible for the suppressed LH secretion in vitellogenic adult turtles.

[Anesthetic management of intraoperatively diagnosed pheochromocytoma--a case report]

Pheochromocytoma is a catecholamine secreting tumor originating from the adrenal medulla (up to 90%), or from the chromaffin tissue along the paravertebral sympathetic chain. The hallmark of pheochromocytoma is paroxysmal hypertension associated with diaphoresis, headache, tremulousness, and palpitations. The triad of diaphoresis, tachycardia, and headache in hypertensive patients is highly suggestive of pheochromocytoma. Other symptoms like flushing, nausea, vomiting, personality changes, and visual disturbances may however cast doubt on the diagnosis of pheochromocytoma. Death resulting from pheochromocytoma is usually due to congestive heart failure, myocardial infarction, or intracerebral hemorrhage. Although less than 0.1 percent of patients with hypertension have a pheochromocytoma, nearly 50 percent of the mortality with unsuspected pheochromocytoma occurred during anesthesia and surgery or parturition. Patients of unsuspected pheochromocytoma have higher risk for surgery, because some mandatory pre-op medical treatments might have been ignored. It is also a challenge to anesthesiologists to handle unsuspected hypertensive crisis during anesthesia and surgery. We presented such a case of unexpected Pheochromocytoma which was mis-diagnosed by the surgeon and was treated as an ordinary adrenal gland tumor and was scheduled for surgical operation. When the patient was undergoing excision of the tumor, manipulations of the tumor initiated an tremendous elevation of the blood pressure. Upon reviewing her history of normotension with visual disturbance, nausea and restlessness, she was immediate treated as with a pheochromocytoma. Appropriate managements were applied to control her abnormally high fluctuating blood pressure with success and with no complications or adverse effect.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo GnRH responsiveness of LH secretion in the female turtle, Trachemys scripta, in relation to the reproductive stage

The effects of several forms of gonadotropin-releasing hormone (GnRH) on the in vivo secretion of luteinizing hormone (LH) were investigated in the female turtle Trachemys scripta. Serial injections of large vitellogenic turtles with 1-2 micrograms (ca. 0.15 micrograms/100 g turtle) of chicken GnRH-I (cGnRH-I) and multiple blood sampling revealed that mature females were unresponsive to GnRH. In contrast, both forms of avian GnRH, cGnRH-I and cGnRH-II, and an avian GnRH analogue (GnRHa) significantly increased circulating levels of LH in previtellogenic turtles. In these turtles, plasma LH increased within 10 min after the initial injection of 0.5 microgram GnRHa or cGnRH-I, but this increase in LH was generally transient and could not be sustained for more than 2 hr even with repeated GnRH injections. Turtles treated with GnRHa on Day 1 showed attenuated pituitary responsiveness to subsequent GnRH challenges on Day 2, whereas turtles treated with both native forms of chicken GnRH remained equally responsive on Day 2. In vitro, GnRHa was more resistant to degradation in plasma than both native forms of GnRH, and the clearance rate of GnRHa in vivo was also slower than that of cGnRH-I. The results show, for the first time, that in vivo GnRH administration stimulates and desensitizes LH secretion in the turtles, but the GnRH responsiveness is related to reproductive status. Furthermore, the results suggest that the desensitizing effects of various forms of GnRH in vivo may be related to their clearance rate.

[Intrathecal meperidine attenuates shivering induced by spinal anesthesia]

Shivering is a common and complex phenomenon that occurs in many patients during spinal anesthesia. Shivering can increase oxygen consumption up to 500 per cent which may be detrimental to patients with decreased myocardial reserve. The metabolic costs and cardiorespiratory consequences of shivering are important particularly for patients with anemia, coronary arterial disease, cardiopulmonary insufficient, debilitated status or are elderly. We studied whether intrathecal meperidine could prevent shivering after spinal anesthesia. 60 patients with ASA class I-II were divided into intrathecal meperidine group (Group I) (n = 30) and control group (Group II) (n = 30). Group I received spinal tetracaine 12-16 mg with meperidine 0.2 mg/kg and Group II received spinal tetracaine 12-16 mg without meperidine. During operation the highest level of spinal anesthesia, ambient and rectal temperatures, blood pressure (BP) and heart rate (HR), presence or absence of shivering, intensity of shivering in both groups were recorded. Close observation for side effects was given post-operatively. There was a significant reduction (p < .005) in incidence of shivering in group I patients (16.7%) when compared with group II (56.7%). There was no or less side effects observed with other neuraxial opioids except nausea. We concluded that intrathecal meperidine could suppress shivering induced by spinal anesthesia.

Differential distribution of chicken-I and chicken-II GnRH in the turtle brain

Chicken-I and chicken-II gonadotropin-releasing hormone (cI-GnRH and cII-GnRH) were shown to be differentially distributed in the brain of a turtle, Trachemys scripta, by HPLC and specific radioimmunoassays. The cI-GnRH was most concentrated in the median eminence (ME), while cII-GnRH was most concentrated in the caudal brain regions, especially medulla and cerebellum. The ratio of cI- to cII-GnRH in the ME of adults was 8:1. Age- and sex-related differences in GnRH concentrations were observed exclusively in the ME: adult females had significantly higher cI-GnRH than younger females and adult males; adult females also had significantly higher cII-GnRH than hatching females. Their differential distribution and sex- and age-related differences suggest that the two peptides may have distinct physiological roles; cI-GnRH is likely the form responsible for stimulating gonadotropin release.

GnRH-induced desensitization of in vitro luteinizing hormone secretion in the turtle, Trachemys scripta

Gonadotropin-releasing hormone (GnRH)-induced desensitization of pituitary luteinizing hormone (LH) secretion in female turtles (Trachemys scripta) was investigated by in vitro superfusion of whole or hemipituitaries with the endogenous forms of the peptide. In sub-adults, LH secretion was rapidly attenuated (desensitized) by both prolonged and pulsatile treatments of chicken II GnRH (cII-GnRH), but pulsatile GnRH administration was more effective than prolonged administration in stimulating LH release. Prolonged administration of chicken I GnRH (cI-GnRH) also desensitized LH secretion; cI-GnRH was slightly less potent than cII-GnRH. GnRH-induced attenuation of LH secretion was not the result of tissue deterioration or depletion of releasable LH: GnRH responsiveness of desensitized pituitaries was fully restored after 4 hr of in vitro recovery, and further LH secretion was induced by tetraethylammonium chloride, a membrane depolarizing agent, in the desensitized glands; TRH-stimulated TSH release did not show desensitization in the same glands. Pituitaries from most adult (vitellogenic) females failed to respond to GnRH challenges; however, when responsive, adult pituitaries also desensitized under prolonged GnRH stimulation and were more resistant to GnRH-induced desnsitization under pulsatile GnRH treatments. Current results show that adult T. scripta typically display lower GnRH sensitivity than the subadults; the latter are like mammals, birds, and goldfish in their susceptibility to desensitization by both forms of endogenous GnRH.

Estrogen-independent growth of mouse vaginal epithelium in organ culture

A serum-free vaginal explant culture system was established to investigate the in vitro effect of estrogen on the growth of mouse vaginal epithelium. Vaginal explants were isolated from 40-day-old, ovariectomized BALB/cCrgl mice and cultured in a basal unsupplemented medium or in basal medium plus various doses of 17 beta-estradiol. Explants were processed for histology at the end of culture periods or were given 4-hour pulses of tritiated thymidine at various times and processed for autoradiography. Vaginal epithelium increased 3- to 5-fold in thickness and 2-fold in the number of epithelial cell layers during 72 hours of culture without estrogen; addition of estrogen did not significantly influence epithelial growth. Keratinization of vaginal epithelium occurred within 48 hours of culture in the absence of estrogen, and again addition of estrogen did not accelerate its appearance. Covering the explants with collagen decreased the estrogen-independent growth of vaginal epithelium. Autoradiography showed that ca. 70-90% of basal epithelial cells entered S phase during the initial 4 hours of culture and that this number declined rapidly after 48 hours to ca. 20%. Addition of 1.8 nM 17 beta-estradiol significantly decreased the labelling index of basal cells at 48 hours, but did not affect the labelling index at 24 and 72 hours. Stromal cells were not labelled at any time. Thus, DNA synthesis, cellular proliferation, and differentiation (keratinization) of vaginal epithelium in organ culture occurred without estrogen and were not stimulated by the addition of estrogen.

Proliferation and differentiation of prepubertal mouse vaginal epithelial cells in vitro and the specificity of estrogen-induced growth retardation

Mouse vaginal epithelial cells were isolated from intact 21-day-old BALB/cCrgl mice and cultured in a serum-free medium (SF20: basal medium supplemented with insulin, epidermal growth factor, transferrin, and bovine serum albumin--fraction V) to examine the proliferation, differentiation, and specificity of estrogen-induced growth retardation in vitro. Histologic and ultrastructural studies showed that vaginal epithelial cells undergo differentiative changes in vitro in the absence of estrogen, and that these changes are similar to those induced in vivo by estrogen. Addition of 17 beta-estradiol inhibited cellular proliferation in a dose-dependent manner. Whereas other estrane derivatives (17 alpha-estradiol and estriol) also significantly retarded cellular proliferation, cholesterol, testosterone, and progesterone had no effect. Keoxifene, an antiestrogen, significantly reversed estrogen-induced growth inhibition, resulting in proliferation of estrogen-treated cells equivalent to that of the untreated control. The results suggest that both proliferation and differentiation of prepubertal mouse vaginal epithelial cells in vitro are estrogen-independent, and that the growth inhibition is a specific estrogen-induced response.

High-pressure liquid chromatographic determination of saccharin in artificial sweeteners and pharmaceuticals

A high-pressure liquid chromatographic procedure is presented for determining saccharin in various formulations. The method is fast, precise, and accurate and is specific for saccharin in the presence of its most likely impurities and degradation products. Reversed-phase chromatography on a micro-C18 column is utilized with an internal standard, and detection is by UV absorption at 280 nm.

Magnifying endoscopic observation of the gastric mucosa, particularly in patients with atrophic gastritis

The gastric mucosal surface was observed using the magnifying fibergastroscope (FGS-ML), and the fine gastric mucosal patterns, which were even smaller than one unit of gastric area, were examined at a magnification of about 30. For simplicification, we classified these patterns by magnifying endoscopy in the following ways; FP, FIP, FSP, SP and MP, modifying Yoshii's classification under the dissecting microscope. The FIP, which was found to have round and long elliptical gastric pits, is a new addition to our endoscopic classification. The relationship between the FIP and the intermediate zone was evaluated by superficial and histological studies of surgical and biopsy specimens. The width of the band of FIP seems to be related to the severity of atrophic gastritis. Also, the transformation of FP to FIP was assessed by comparing specimens taken from the resected and residual parts of the stomach, respectively. Moreover, it appears that severe gastritis occurs in the gastric mucosa which shows a FIP. Therefore, we consider that the FIP indicates the position of the atrophic border.