Fructose-induced insulin resistance and hypertension in rats

To determine if hypertension could be produced in normal rats by feeding them a fructose-enriched diet, Sprague-Dawley rats were fed either normal chow or a diet containing 66% fructose as a percentage of total calories for approximately 2 weeks. At the end of this period systolic blood pressure had increased from 124 +/- 2 to 145 +/- 2 (SEM) mm Hg in the fructose-fed rats, whereas no change occurred in the control group. In addition, hyperinsulinemia and hypertriglyceridemia were associated with hypertension in fructose-fed rats. The addition of clonidine to the drinking water inhibited fructose-induced hypertension, but not the increase in plasma insulin or triglyceride concentration seen in fructose-fed rats. Thus, the metabolic changes associated with fructose-induced hypertension are unlikely to be secondary to an increase in sympathetic activity. Whether or not this is also true of the hypertension remains to be clarified.

Use of the International Knee Documentation Committee guidelines to assess outcome following anterior cruciate ligament reconstruction

The purpose of this project was to determine if guidelines established by the International Knee Documentation Committee (IKDC) could distinguish differences in outcome, as indicated by the patients' subjective rating of knee function following ACL reconstruction, and to determine if all subgroups included in the IKDC rating system contribute to the prediction of the overall final IKDC rating. A total of 133 patients undergoing ACL reconstruction were evaluated according to IKDC guidelines 1-5 years postoperatively. Each subject was rated in each of four subgroups on the IKDC scale: patient subjective assessment, symptoms, range of motion (ROM), and laxity. The worst rating for the subgroups defined the overall final rating. The outcome from the patient's perspective was determined by asking them to rate the function of their knee on a scale from 0 to 100 with 100 being the level of function before injury. Average length of follow-up was 3.2 years (range 1.1-6.3 years). ANOVA indicated that the patients' subjective rating of knee function on a scale from 0 to 100 differed according to the overall final IKDC rating (F = 16.1, P < 0.001). The average subjective rating of knee function for those with a normal IKDC rating was 95.2, nearly normal was 91.2, abnormal was 84.9, and severely abnormal was 75.4. The average subjective rating of knee function for those who were severely abnormal was significantly different from those rated normal, nearly normal, and abnormal, and the average subjective rating for those who were abnormal was significantly different from those who were normal or nearly normal. There was no significant difference in average subjective rating between those who were rated as normal or nearly normal. Regression analysis indicated that all four subgroups contributed significantly to the prediction of the final IKDC rating (r2 = 0.70), but the majority of the variance (62%) was accounted for by symptoms and laxity. These results appear to indicate that the IKDC guidelines are useful for describing the outcome following ACL reconstruction. Further testing of the IKDC guidelines is necessary to determine if they are capable of detecting a change in the patients over time following treatment and/or surgery of the knee.

Comparative pharmacology of chemically distinct NADPH oxidase inhibitors

BACKGROUND AND PURPOSE

Oxidative stress [i.e. increased levels of reactive oxygen species (ROS)] has been suggested as a pathomechanism of different diseases, although the disease-relevant sources of ROS remain to be identified. One of these sources may be NADPH oxidases. However, due to increasing concerns about the specificity of the compounds commonly used as NADPH oxidase inhibitors, data obtained with these compounds may have to be re-interpreted.

EXPERIMENTAL APPROACH

We compared the pharmacological profiles of the commonly used NADPH oxidase inhibitors, diphenylene iodonium (DPI), apocynin and 4-(2-amino-ethyl)-benzolsulphonyl-fluoride (AEBSF), as well as the novel triazolo pyrimidine VAS3947. We used several assays for detecting cellular and tissue ROS, as none of them is specific and artefact free.

KEY RESULTS

DPI abolished NADPH oxidase-mediated ROS formation, but also inhibited other flavo-enzymes such as NO synthase (NOS) and xanthine oxidase (XOD). Apocynin interfered with ROS detection and varied considerably in efficacy and potency, as did AEBSF. Conversely, the novel NADPH oxidase inhibitor, VAS3947, consistently inhibited NADPH oxidase activity in low micromolar concentrations, and interfered neither with ROS detection nor with XOD or eNOS activities. VAS3947 attenuated ROS formation in aortas of spontaneously hypertensive rats (SHRs), where NOS or XOD inhibitors were without effect.

CONCLUSIONS AND IMPLICATIONS

Our data suggest that triazolo pyrimidines such as VAS3947 are specific NADPH oxidase inhibitors, while DPI and apocynin can no longer be recommended. Based on the effects of VAS3947, NADPH oxidases appear to be a major source of ROS in aortas of SHRs.

A randomized controlled trial of filgrastim as an adjunct to antibiotics for treatment of hospitalized patients with community-acquired pneumonia. CAP Study Group

Because of the critical role of neutrophils in host defenses, it was hypothesized that stimulation of neutrophil production and function with Filgrastim would improve the outcome of hospitalized patients with community-acquired pneumonia. To test this hypothesis, a randomized, placebo-controlled, multicenter trial of Filgrastim (300 micrograms/day up to 10 days) as an adjunct to antibiotics was conducted for these patients. Outcome measures included time to resolution of morbidity (TRM, a composite measure of temperature, respiratory rate, blood oxygenation, and chest radiograph), 28-day mortality, length of stay, and adverse events. Filgrastim increased blood neutrophils 3-fold, but TRM, mortality, and length of hospitalization were not affected. Treatment, however, accelerated radiologic improvement and appeared to reduce serious complications (e.g., empyema, adult respiratory distress syndrome, and disseminated intravascular coagulation). Filgrastim administration was safe and well tolerated in these patients. Additional trials are needed to establish the value of this approach to treatment of infectious diseases.

Human interferon-gamma-inducible protein 10 (IP-10) inhibits constitutive signaling of Kaposi's sarcoma-associated herpesvirus G protein-coupled receptor

A G protein-coupled receptor (GPCR) is encoded within the genome of Kaposi's sarcoma- associated herpesvirus (KSHV)/human herpesvirus 8, a virus that may be involved in the pathogenesis of Kaposi's sarcoma and primary effusion lymphomas. KSHV-GPCR exhibits constitutive signaling activity that causes oncogenic transformation. We report that human interferon (IFN)-gamma-inducible protein 10 (HuIP-10), a C-X-C chemokine, specifically inhibits signaling of KSHV-GPCR. In contrast, monokine induced by IFN-gamma (HuMig), which like HuIP-10 is an agonist of C-X-C chemokine receptor 3, does not inhibit KSHV-GPCR signaling. Moreover, HuIP-10, but not HuMig, inhibits KSHV-GPCR-induced proliferation of NIH 3T3 cells. These results show that HuIP-10 is an inverse agonist that converts KSHV-GPCR from an active to an inactive state. Thus, a human chemokine inhibits constitutive signaling and cellular proliferation that is mediated by a receptor encoded by a human disease-associated herpesvirus.

Palmar plate fixation of AO type C2 fracture of distal radius using a locking compression plate--a biomechanical study in a cadaveric model

The stability of palmar plate fixation using a locking compression T-plate was compared with that of a conventional palmar T-plate and a dorsal T-plate in a cadaveric model of an AO type C2 fracture of distal radius. The wrist axial load transmission through the radius was tested for each fixation. The results show that, under 100N axial load, the palmar locking compression T-plate restores stability comparable to that of the intact radius, and is superior to conventional palmar or dorsal T-plates.

Somatostatin inhibition of fructose-induced hypertension

The role of insulin resistance and hyperinsulinemia in the etiology of fructose-induced hypertension was studied in male Sprague-Dawley rats. Rats consumed a fructose-enriched diet (containing 66% of total calories as fructose) for 11 days and were infused continuously during the last 7 days with either a somatostatin analogue or vehicle. At the end of this period, rats receiving the somatostatin analogue had a lower plasma insulin concentration (52 +/- 4 vs. 70 +/- 6 microunits/ml, p less than 0.01) and a lower blood pressure (133 +/- 2 vs. 150 +/- 2 mm Hg) than did the rats infused with the control solution. In addition, the increase in plasma triglyceride concentration in response to the fructose-enriched diet was significantly attenuated (p less than 0.001) in the rats infused with somatostatin. These data provide further support that the increase in blood pressure that occurs when normal rats are fed a high fructose diet is dependent on the ability of this intervention to cause insulin resistance and hyperinsulinemia.

Effect of age and diet on insulin secretion and insulin action in the rat

The effects of aging on various aspects of insulin secretion and action were studied in male Sprague-Dawley rats, maintained from 1 1/2 to 12 mo of age on conventional rat chow, sucrose-rich, or calorie-restricted diets. In chow-fed rats, islet volume increased as the animals grew from 1 1/2 to 12 mo of age, but glucose-stimulated insulin secretion (per volume islet) declined over the same interval. In addition, in vivo insulin-stimulated glucose utilization fell in these rats. However, the plasma insulin response to an oral glucose challenge was sufficient to prevent frank decompensation of glucose tolerance (presumably due to an increase in total pancreatic endocrine cell mass). All these changes, with the exception of the decline in glucose-stimulated insulin secretion per volume islet, were accentuated by feeding sucrose. Thus, 12-mo-old sucrose-fed rats had larger islets and higher plasma insulin levels in response to an oral glucose challenge, and the rats were more insulin-resistant than chow-fed rats. However, glucose-stimulated insulin release per volume islet was similar in 12-mo-old chow-fed and sucrose-fed rats. In contrast, calorie restriction led to an amelioration in all but one of the age-related changes, i.e., islets from calorie-restricted rats were comparable in size to those of 2-mo-old rats, the animals had lower plasma insulin levels in response to an oral glucose load, and they were less insulin resistant than the other two groups of 12-mo-old rats. On the other hand, glucose-stimulated insulin secretion per volume islet was similar to that of the other 12-mo-old rats. These results suggest that aging leads to marked changes in both insulin secretion and insulin action. The decline in glucose-stimulated insulin secretion per unit endocrine pancreas appears to be an inevitable consequence of the aging process. In contrast, the age-related changes in islet size, insulin response to a glucose load, and in vivo insulin-stimulated glucose uptake are extremely responsive to variations in amount and kind of calories. DIABETES 32:175-180, February 1983.

Attenuation of fructose-induced hypertension in rats by exercise training

This study was initiated to see if the insulin resistance, hyperinsulinemia, and hypertension that follow feeding normotensive Sprague-Dawley rats a fructose-rich diet could be prevented by letting rats run spontaneously in exercise wheel cages. Blood pressure in sedentary rats increased from (mean +/- SEM) 125 +/- 2 to 148 +/- 3 mm Hg in response to 2 weeks of a high fructose diet, and this increment was significantly (p less than 0.001) attenuated in exercising rats (from 121 +/- 1 to 131 +/- 2 mm Hg). In addition, mean (+/- SEM) plasma insulin concentration was lower in fructose-fed rats allowed to run spontaneously (44 +/- 2 vs 62 +/- 5 microU/ml; p less than 0.01). Finally, resistance to insulin-stimulated glucose uptake was assessed by determining the steady state plasma glucose response to a continuous glucose and exogenous insulin infusion during a period in which endogenous insulin secretion was suppressed. The results of these studies indicated that the mean (+/- SEM) steady state plasma glucose concentration was significantly lower in the exercise-trained rats (127 +/- 5 vs 168 +/- 6 mg/dl; p less than 0.001), despite the fact that the steady state plasma insulin levels were also lower in rats allowed to run spontaneously (75 +/- 4 vs 90 +/- 5 microU/ml; p less than 0.05). Thus, the ability of exercise-trained rats to stimulate glucose disposal was enhanced as compared with that of sedentary rats fed the same fructose-rich diet. These data demonstrate that the insulin resistance, hyperinsulinemia, and hypertension produced in normotensive rats by feeding them a high fructose diet can be attenuated if rats are allowed to run spontaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Perinatal ontogeny of brain growth in the domestic pig

The perinatal development of the brain is highlighted by a growth spurt whose timing varies among species. The growth of the porcine cerebrum was investigated from the third trimester of gestation (70 days postconception) through the first 3.5 weeks of postnatal life (140 days postconception). The shape of the growth curves for cerebrum weight, total protein mass, total cell number (estimated by DNA content), and myelination (estimated by cholesterol accretion) were described. The growth velocity of cerebrum weight had two peaks, one at 90 days and the other at 130 days postconception, whereas that of total protein was greatest from 90 to 130 days postconception, and that of total DNA was greatest between 90 and 110 days and again at 130 days postconception. The growth velocity for total cholesterol continued to increase during the entire period, suggesting that myelination continued after the growth spurts for cells (protein and DNA). The growth velocity patterns observed in these contemporary pigs suggest that this species may be an appropriate model for human brain development, not only in the perinatal pattern of increase in mass of the cerebrum, as established previously, but also with regard to the patterns of cellular development and myelination.

Sugar-induced hypertension in Sprague-Dawley rats

Male Sprague-Dawley rats were fed either conventional rat chow, or a diet in which vegetable starch was replaced with either glucose or sucrose for two weeks. At the end of this period, measurements were made of weight, blood pressure, and plasma glucose, insulin, and triglyceride concentrations. The average weight gain over the dietary period was approximately 75 g, and did not vary between the three groups. Mean (+/- SEM) blood pressure remained stable in the rats fed conventional chow (124 +/- 2 to 127 +/- 3 mm Hg), but increased significantly in rats fed the glucose-enriched diet (122 +/- 1 to 134 +/- 2 mm Hg, P less than .02, compared to chow-fed rats). The increase in blood pressure was even greater in rats fed the sucrose-enriched diet (122 +/- 2 to 144 +/- 2), and was significantly greater (P less than .005) than in rats fed either conventional chow or the glucose-enriched diet. Plasma glucose concentrations did not change in any of the groups, but plasma insulin concentration approximately doubled in rats fed either the glucose-enriched or sucrose-enriched diets. Finally, plasma triglyceride concentrations also were significantly higher (P less than .002) in both glucose-fed and sucrose-fed rats than in the control group. However, the increase was greatest in the sucrose-fed rats, and was significantly higher than in rats fed the glucose-enriched diet (P less than .002).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomembrane permeation of nicotine: mechanistic studies with porcine mucosae and skin

In the present study, the permeation and partitioning of nicotine as a function of pH was investigated with various regions of skin and absorptive mucosae that were freshly excised from domestic pigs. As an ionizable compound (pKa values of 3.04 and 7.84), nicotine in solutions of different pH values provides a model for determining the influence of the charge status of a molecule on permeation. The permeation of nicotine across porcine mucosae and skin followed zero-order kinetics. The rate of permeation was dependent on donor solution pH and increased exponentially as the pH increased. With an exception of the nasal mucosa, which showed similar permeabilities for all species of nicotine, the permeability of nicotine across various skin and mucosal specimens was significantly higher (p < 0.001) for the un-ionized species (NN) than for the ionized species (NNH+, NH+NH+). It was also seen that un-ionized nicotine molecules were more permeable through absorptive mucosae (nasal, buccal, sublingual, and gingival) than through skin (abdominal, dorsal, thigh, and ear pinna). Partition studies were performed and the results further confirmed that biomembrane permeation of nicotine follows the pH-partition theory.

A prospective controlled study of the risk of bacteremia in emergency sclerotherapy of esophageal varices

Reported incidences of bacteremia after endoscopy with esophageal variceal sclerotherapy are conflicting. A prospective controlled study was conducted to determine the frequency of bacteremia after emergency endoscopy with esophageal variceal sclerotherapy compared with frequency after elective esophageal variceal sclerotherapy and after emergency endoscopy in patients with upper gastrointestinal bleeding from nonvariceal sources. A total of 126 endoscopies were studied in 72 patients. Groups consisted of (a) emergency endoscopy without esophageal variceal sclerotherapy, 37 sessions with 36 patients; (b) elective esophageal variceal sclerotherapy, 33 sessions with 14 patients; and (c) emergency esophageal variceal sclerotherapy, 56 sessions with 36 patients. Blood cultures were obtained before and 5 and 30 minutes after endoscopy. There was a higher frequency of preendoscopic bacteremia in emergency esophageal variceal sclerotherapy (13%) than in emergency endoscopy alone (0%) (P = 0.02). Clinically significant bacteremia in emergency esophageal variceal sclerotherapy was observed in 7 of 56 (13%) sessions, compared with 0 of 33 in elective esophageal variceal sclerotherapy (P = 0.03) and 1 of 36 (3%) in emergency endoscopy alone (P = 0.45). Of these cases, 3 (5.4%) were potentially caused by emergency esophageal variceal sclerotherapy, but not clinically significant postendoscopic bacteremia was attributable to the procedure in the other groups.

Identifying barriers to healthcare delivery and access in the Circumpolar North: important insights for health professionals

Lack of access to healthcare services for people living in the Circumpolar North may have important consequences for their health and well-being, both in terms of the actual treatment and other possible health-related consequences intertwined with their life situation. The aim of the present study was to identify the specific challenges to healthcare service delivery and access for populations in the Circumpolar North that are addressed in contemporary literature. A scoping review of literature published between 2005 and 2016 was conducted and 43 articles were selected for inclusion into the review. The review findings address 4 main themes identified in the literature: (1) the influence of physical geography, (2) healthcare provider-related barriers, (3) the importance of culture and language and (4) the impact of systemic factors. The review of the literature enabled us to identify existing gaps in both health service access and issues discussed in the available literature, particularly for informing healthcare services in the Circumpolar North, as well as point towards opportunities for future research. The thematic findings drawn from interdisciplinary and international literature inform understandings of the impact of health system barriers on healthcare services and the opportunities for Northern residents to support their own health.

Caffeine ameliorates hemodynamic derangements and portosystemic collaterals in cirrhotic rats

Portal hypertension (PH), a pathophysiological derangement of liver cirrhosis, is characterized by hyperdynamic circulation, angiogenesis, and portosystemic collaterals. These may lead to lethal complications, such as variceal bleeding. Caffeine has been noted for its effects on liver inflammation, fibrogenesis, and vasoreactiveness. However, the relevant influences of caffeine in cirrhosis and PH have not been addressed. Spraque-Dawley rats with common bile duct ligation-induced cirrhosis or sham operation received prophylactic or therapeutic caffeine treatment (50 mg/kg/day, the first or 15th day since operation, respectively) for 28 days. Compared to vehicle (distilled water), caffeine decreased cardiac index, increased systemic vascular resistance, reduced portal pressure (PP), superior mesenteric artery flow, mesenteric vascular density, portosystemic shunting (PSS), intrahepatic angiogenesis, and fibrosis without affecting liver and renal biochemistry. The beneficial effects were reversed by selective adenosine A1 agonist N6-cyclopentyladenosine (CPA) or A2A agonist GCS21680. Both prophylactic and therapeutic caffeine treatment decreased portal resistance and PP in thioacetamide (200mg/kg, thrice-weekly for 8 weeks)-induced cirrhotic rats. Caffeine down-regulated endothelial nitric oxide synthase, vascular endothelial growth factor (VEGF), phospho-VEGFR2, and phospho-Akt mesenteric protein expression. Caffeine adversely affected viability of hepatic stellate and sinusoidal endothelial cells, which was reversed by CPA and GCS21680. On the other hand, caffeine did not modify vascular response to vasoconstrictors in splanchnic, hepatic, and collateral vascular beds.

CONCLUSIONS

Caffeine decreased PP, ameliorated hyperdynamic circulation, PSS, mesenteric angiogenesis, hepatic angiogenesis, and fibrosis in cirrhotic rats. Caffeine may be a feasible candidate to ameliorate PH-related complications in cirrhosis.

Antimicrobial resistance and virulence genes of Streptococcus isolated from dairy cows with mastitis in China

Streptococcus is a major mastitis-causing pathogen in dairy cows. To investigate the prevalence, antimicrobial resistance and virulence gene of Streptococcus in mastitic milk, a total of 735 mastitic raw milk samples from dairy cows in 11 provinces of China were collected and tested. Antimicrobial resistance of Streptococcus isolates was determined by disc diffusion against 8 classes 29 antimicrobial agents, and Streptococcus resistant genes and virulence genes were determined by PCR and agarose gel electrophoresis. A total of 64 (8.71%) isolates of Streptococcus were isolated and identified using biochemical profiling, including 22 isolates of Streptococcus agalactiae, 13 isolates of Streptococcus dysgalactiae, and 29 isolates of Streptococcus uberis. Out of 64 resistant Streptococcus isolates, all isolates (100%) were resistant to 3 or more antimicrobials. The most frequency (n = 18, 28.12%) of the isolates were multi-resistant to 5-7 antimicrobials and the highest multi-resistant number was 29 (n = 1, 1.56%). Streptococcus isolates had the highest resistance rate to tetracycline (98.44%) and oxacillin (98.44%), followed by penicillin G (96.88%) and doxycycline (96.88%), and the lowest resistance was observed with respect to ciprofloxacin (1.56%). A total of 16 antimicrobials resistance genes with 25 combination patterns were detected in the isolates. The gene combination of Sul1/Sul2/Sul3 + gyrA/parC + cat1/cat2 was the most common pattern (12.5%). The correlation between resistant phenotypes and resistance genes in Streptococcs was 35.87%. A total of 7 virulence genes were detected and 59 (92.19%) isolates harbored at least one gene. Twenty-four classes of gene patterns were found in the isolates and the patterns of bca (9.38%) and cfb (9.38%) were the most prevalent form. In conclusion, the issue of drug resistance of Streptococcus is still a great concern in cattle health in China.

Robotic transperineal prostate biopsy: pilot clinical study

OBJECTIVE

To develope a robot (BioXbot) that performs mapping transperineal prostate biopsy (PB) with two perineal skin punctures under ultrasound guidance. Our pilot study's clinical endpoints were complications and its technical endpoints were the duration for each phase.

METHODS

This institution review board-approved prospective clinical trial included patients with indications for PB. Two urologists performed these PBs. In the lithotomy position and under general anesthesia, the transrectal biplane ultrasound probe acquired transverse images of the prostate gland. The urologist defined its boundaries and planned the biopsy. It guided the PB in 3 axes, passing through a single perineal skin puncture for each prostate side. After each biopsy, it automatically moved to the next position. The steps were repeated on the contralateral side.

RESULTS

Our 20 patients had a mean prostate-specific antigen of 8.4 ± 4.9 ng/mL. Two patients had 2 previous biopsies, whereas the rest had one. The mean number of biopsies taken was 28.5 ± 6.2 in a mean total procedure time of 32.5 ± 3.2 minutes. We detected 3 patients with prostate cancer with Gleason score 3 + 3. Two patients required brief bladder catheterization after their biopsy. Their prostate volumes were >50 mL and the number of biopsies taken was >30 cores. There was no mechanical failure, sepsis, bleeding per-rectal, or perineal hematoma.

CONCLUSION

This pilot study demonstrated BioXbot's safety and feasibility as a biopsy platform. It can potentially be used for image-guided PB and focal therapy.

Procedures for reproducible detection of rabies virus antigen mRNA and genome in situ in formalin-fixed tissues

Procedures allowing the reproducible in situ detection of rabies virus antigen and RNAs (both genome and message) in formalin-fixed tissue are described. These procedures can be used on sequential tissue sections and thereby permit comparison of results from tests detecting both antigen and RNA in the same tissue. This antigen-detecting procedure has also been used to identify both the phylogenetically distant rabies viruses from silver-haired bat and vampire bat and the rabies-related viruses Mokola, Duvenhage, and Lagos bat. One of the critical steps in these procedures is the digestion (and the resulting exposure of the target molecules) with proteinase K. These methods may be useful for the identification of other viruses of public health importance. Because in many situations only formalin-fixed tissue is available for postmortem diagnosis, the technical ability to identify a virus antigen and nucleic acid in such tissues greatly extends potential diagnostic capabilities.

Blastocystis hominis infection and intestinal injury

Blastocystis hominis is an enteric protozoan associated with clinical illness. To determine the prevalence of intestinal injury in patients with B. hominis infection, the authors prospectively evaluated 18 patients with B. hominis infection by endoscopy and a test of intestinal permeability. Seventeen patients had gastrointestinal symptoms. Colonic mucosa appeared normal by lower endoscopy in 12 of 13 patients, and was friable slightly in 1. Duodenal mucosa was normal by upper endoscopy in nine patients. Pathologic examination of mucosal biopsy specimens did not demonstrate evidence of mucosal invasion. 51Cr-edetic acid (51Cr-EDTA) was given to the 18 patients with stools positive for B. hominis and to 32 healthy control subjects. Approximately 100 uCi of 51Cr-EDTA was given orally after an overnight fast, and urine was collected for the following 24 hours. Mean 24-hour urinary excretion of 51Cr-EDTA, calculated as a percent of the administered dose, was 1.31% (0.34-2.76%) in patients with B. hominis infection and 1.99% (0.59-3.48%) in the control subjects. The intestinal permeability to 51Cr-EDTA in blastocystis-infected individuals was not increased, but was decreased significantly compared with healthy subjects (p < 0.005). Therefore, in a group of symptomatic patients with B. hominis infection, endoscopy typically did not show evidence of significant intestinal inflammation, and results of intestinal permeability testing with 51Cr-EDTA did not suggest impaired barrier function of the intestinal mucosa. The clinical literature on B. hominis infection and intestinal injury is reviewed.

Myocardial protection during ventricular fibrillation by reduction of proton-driven sarcolemmal sodium influx

Although the inhibition of proton-driven sarcolemmal sodium influx ameliorates ischemic injury in the quiescent myocardium, the effects when ventricular fibrillation is present are largely unknown. We used an isolated rat heart model to investigate whether inhibition of the sodium-hydrogen exchanger isoform-1 (with the benzoylguanidine derivatives HOE-694 and cariporide) with or without concomitant inhibition of the sodium-bicarbonate co-transporter (with perfusate buffered with N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid [HEPES]) during ischemia and ventricular fibrillation could ameliorate functional myocardial abnormalities presumed to limit cardiac resuscitability. Ischemic contracture, which typically develops during ventricular fibrillation, was ameliorated by HOE-694 when either a bicarbonate-buffered (20 +/- 7 mm Hg vs 15 +/- 5 mm Hg, P <.05) or a HEPES-buffered (14 +/- 5 mm Hg vs 10 +/- 3 mm Hg, P <.04) perfusate was used. Maximal amelioration occurred when cariporide and HEPES-buffered perfusate were used simultaneously (25 +/- 14 mm Hg vs 11 +/- 3 mm Hg, P <.01), and this was accompanied by lesser leftward shifts of the end-diastolic pressure-volume curves after defibrillation. Intramyocardial sodium increases of 76% during ischemia and ventricular fibrillation (P <.05) were ameliorated by the sodium-influx-limiting interventions. Thus interventions limiting sarcolemmal sodium influx during ischemia and ventricular fibrillation may facilitate successful resuscitation from ventricular fibrillation.

Material identification using real and simulated thermal cues

The objective of this study was to develop a thermal display for simulating the thermal cues associated with making contact with materials with different thermal properties. The thermal display was designed based on a semiinfinite body model. The performance of subjects using this display was compared to that with real materials in a material identification experiment. The results indicated that there was no significant difference in material identification when subjects were presented with real or simulated materials. The decreases in skin temperature were also comparable in the two experiments and were related to the contact coefficient of the material palpated, which is consistent with the semiinfinite body model. These findings suggest that thermal feedback in a haptic display can facilitate object recognition when visual cues are limited.

Differential in vivo tumorigenicity of diverse KRAS mutations in vertebrate pancreas: A comprehensive survey

Somatic activation of the KRAS proto-oncogene is evident in almost all pancreatic cancers, and appears to represent an initiating event. These mutations occur primarily at codon 12 and less frequently at codons 13 and 61. While some studies have suggested that different KRAS mutations may have variable oncogenic properties, to date there has been no comprehensive functional comparison of multiple KRAS mutations in an in vivo vertebrate tumorigenesis system. We generated a Gal4/UAS-based zebrafish model of pancreatic tumorigenesis in which the pancreatic expression of UAS-regulated oncogenes is driven by a ptf1a:Gal4-VP16 driver line. This system allowed us to rapidly compare the ability of 12 different KRAS mutations (G12A, G12C, G12D, G12F, G12R, G12S, G12V, G13C, G13D, Q61L, Q61R, and A146T) to drive pancreatic tumorigenesis in vivo. Among fish injected with one of five KRAS mutations reported in other tumor types but not in human pancreatic cancer, 2/79 (0.25%) developed pancreatic tumors, with both tumors arising in fish injected with A146T. In contrast, among fish injected with one of seven KRAS mutations known to occur in human pancreatic cancer, 22/106 (20.8%) developed pancreatic cancer. All eight tumorigenic KRAS mutations were associated with downstream MAPK/ERK pathway activation in preneoplastic pancreatic epithelium, while non-tumorigenic mutations were not. These results suggest that the spectrum of KRAS mutations observed in human pancreatic cancer reflects selection based upon variable tumorigenic capacities, including the ability to activate MAPK/ERK signaling.

The gene expression of the amiloride-sensitive epithelial sodium channel alpha-subunit is regulated by antagonistic effects between glucocorticoid hormone and ras pathways in salivary epithelial cells

The functional expression of the amiloride-sensitive epithelial sodium channel (ENaC) in select epithelia is critical for maintaining electrolyte and fluid homeostasis. Although ENaC activity is strictly dependent upon its alpha-subunit expression, little is known about the molecular mechanisms by which cells modulate alpha-ENaC gene expression. Previously, we have shown that salivary alpha-ENaC expression is transcriptionally repressed by the activation of Raf/extracellular signal-regulated protein kinase pathway. Here, this work further investigates the molecular mechanism(s) by which alpha-ENaC expression is regulated in salivary epithelial Pa-4 cells. A region located between -1.5 and -1.0 kilobase pairs of the alpha-ENaC 5'-flanking region is demonstrated to be indispensable for the maximal and Ras-repressible reporter expression. Deletional analyses using heterologous promoter constructs reveal that a DNA sequence between -1355 and -1269 base pairs functions as an enhancer conferring the high level of expression on reporter constructs, and this induction effect is inhibited by Ras pathway activation. Mutational analyses indicate that full induction and Ras-mediated repression require a glucocorticoid response element (GRE) located between -1323 and -1309 base pairs. The identified alpha-ENaC GRE encompassing sequence (-1334/-1306) is sufficient to confer glucocorticoid receptor/dexamethasone-dependent and Ras-repressible expression on both heterologous and homologous promoters. This report demon- strates for the first time that the cross-talk between glucocorticoid receptor and Ras/extracellular signal-regulated protein kinase signaling pathways results in an antagonistic effect at the transcriptional level to modulate alpha-ENaC expression through the identified GRE. In summary, this study presents a mechanism by which alpha-ENaC expression is regulated in salivary epithelial cells.