Chronic estrogen treatment increases levels of endothelial nitric oxide synthase protein in rat cerebral microvessels

BACKGROUND AND PURPOSE

A number of studies indicate that the female gonadal hormone, estrogen, confers protection against cerebrovascular disorders such as stroke. One postulated mechanism for these effects of estrogen is an action on the enzyme endothelial nitric oxide synthase (eNOS), which produces the vasodilatory molecule NO. We have investigated the hypothesis that estrogen increases expression of eNOS in cerebral microvessels of male and female rats.

METHODS

We measured levels of eNOS protein by Western blot in cerebral microvessels isolated from 7 groups of animals: females, ovariectomized females, ovariectomized females treated with estrogen, males, castrated males, castrated males treated with estrogen, and castrated males treated with testosterone.

RESULTS

Ovariectomized female rats treated with estrogen had 17. 4-fold greater levels of eNOS protein in cerebral microvessels than ovariectomized females, and intact females had 16.6-fold greater levels than ovariectomized females (P<0.01). In intact females, cerebral microvessel eNOS protein levels were 9.2-fold higher than those of intact males (P<0.05). Levels of eNOS protein in castrated males, castrated males treated with testosterone, and males were not different from each other. Estrogen treatment of castrated animals resulted in an 18.8-fold increase in cerebral microvessel eNOS protein (P<0.05).

CONCLUSIONS

Chronic estrogen treatment increases levels of eNOS protein in cerebral microvessels of male and female rats. This increase in eNOS protein correlates with our previous functional findings indicating that estrogen exposure increases NO modulation of cerebrovascular reactivity in both male and female animals. Upregulation of eNOS expression may contribute to the neuroprotective effect of estrogen.

Continuity and change in the social competence of children with autism, Down syndrome, and developmental delays

The aims of this longitudinal study were: (1) to assess the continuity and change in diagnosis, intelligence, and language skills in children with autism, Down syndrome, and other developmental delays, (2) to specify the deficits in social competence and language skills in these children, and (3) to identify precursors in the preschool period of gains in language skills and of peer engagement in the mid-school years. The initial sample consisted of 70 children with autism, 93 children with Down syndrome, 59 children with developmental delays, and 108 typically developing children, with the first three groups of children studied when they were between 2 and 6 years of age. At follow-up, 51 children with autism, 71 children with Down syndrome, and 33 children with developmental delays were assessed at mean ages around 10-13 years. The long-term follow-up showed little change in the diagnosis of autism but sizeable improvements in intellectual and language abilities within the autistic group, a pattern that was not seen in the children with Down syndrome. Unique deficits in joint attention, some forms of representational play, responsiveness to the emotions of others, and initiation of peer engagement were identified in the autistic children, whereas the children with Down syndrome seemed to have a specific deficit only in language. Joint attention skills were concurrently associated with language abilities in all groups and predicted long-term gains in expressive language for the children with autism. Children with autism, regardless of their level of functioning, were less socially engaged with classmates than the other developmentally disabled children because they infrequently initiated and accepted play bids, not because they were rebuffed by peers. Early nonverbal communication and play skills were predictors of the frequency of initiations of peer play for the children with Down syndrome as well as the extent of peer engagement of the children with autism. These results suggest that improvements in early communication and play skills may have long-term consequences for later language and social competence in these groups of children.

Different mismatch repair deficiencies all have the same effects on somatic hypermutation: intact primary mechanism accompanied by secondary modifications

Somatic hypermutation of Ig genes is probably dependent on transcription of the target gene via a mutator factor associated with the RNA polymerase (Storb, U., E.L. Klotz, J. Hackett, Jr., K. Kage, G. Bozek, and T.E. Martin. 1998. J. Exp. Med. 188:689-698). It is also probable that some form of DNA repair is involved in the mutation process. It was shown that the nucleotide excision repair proteins were not required, nor were mismatch repair (MMR) proteins. However, certain changes in mutation patterns and frequency of point mutations were observed in Msh2 (MutS homologue) and Pms2 (MutL homologue) MMR-deficient mice (for review see Kim, N., and U. Storb. 1998. J. Exp. Med. 187:1729-1733). These data were obtained from endogenous immunoglobulin (Ig) genes and were presumably influenced by selection of B cells whose Ig genes had undergone certain mutations. In this study, we have analyzed somatic hypermutation in two MutL types of MMR deficiencies, Pms2 and Mlh1. The mutation target was a nonselectable Ig-kappa gene with an artificial insert in the V region. We found that both Pms2- and Mlh1-deficient mice can somatically hypermutate the Ig test gene at approximately twofold reduced frequencies. Furthermore, highly mutated sequences are almost absent. Together with the finding of genome instability in the germinal center B cells, these observations support the conclusion, previously reached for Msh2 mice, that MMR-deficient B cells undergoing somatic hypermutation have a short life span. Pms2- and Mlh-1-deficient mice also resemble Msh2-deficient mice with respect to preferential targeting of G and C nucleotides. Thus, it appears that the different MMR proteins do not have unique functions with respect to somatic hypermutation. Several intrinsic characteristics of somatic hypermutation remain unaltered in the MMR-deficient mice: a preference for targeting A over T, a strand bias, mutational hot spots, and hypermutability of the artificial insert are all seen in the unselectable Ig gene. This implies that the MMR proteins are not required for and most likely are not involved in the primary step of introducing the mutations. Instead, they are recruited to repair certain somatic point mutations, presumably soon after these are created.

Effect of eradication of Helicobacter pylori on the benign gastric ulcer recurrence--a 24 month follow-up study

OBJECTIVES

To evaluate the effect of eradication of Helicobacter pylori (H. pylori) on the recurrence of benign gastric ulcer (BGU) in the patients with BGU.

METHODS

This study was performed for 40 H. pylori-positive BGU patients cured of BGU and H. pylori eradicated, and for 25 H. pylori-positive patients (non-eradicated group) who were not treated with H. pylori eradication regimen or H. pylori was not eradicated. Four different methods--CLOtest, microscopy of Gram stained mucosal smear, culture and histology of modified Giemsa staining--were taken for identifying colonization of H. pylori before treatment, and 4 weeks after completion of triple therapy. For the control group in which triple therapy was not tried, follow-up gastroscopy was done to confirm the healing of the ulcer. To detect BGU recurrence, the gastroscopy was performed at 6, 12, 18, and 24 months after therapy.

RESULTS

In the non-eradicated group, the BGU recurrence rate was 16% within 6 months, 40% within 1 year, 56% within 18 months and 60% within 2 years. The respective recurrence rates in the 40 patients in whom the bacteria had been eradicated were 0%, 7.5%, 10% and 10% (4 patients), respectively. Among the four BGU-recurred patients in whom H. pylori had been eradicated, one patient was found to have BGU recurring with H. pylori positive again in one year, and another two patients had NSAIDs ingestion history.

CONCLUSION

The eradication of H. pylori in patients with BGU reduces the recurrence of BGU. In addition, the major causes of BGU recurrence look like NSAIDs ingestion and reinfection of H. pylori.

Web based 3-D medical image visualization on the PC

With the recent advance of Web and its associated technologies, information sharing on distribute computing environments has gained a great amount of attention from many researchers in many application areas, such as medicine, engineering, and business. One basic requirement of distributed medical consultation systems is that geographically dispersed, disparate participants are allowed to exchange information readily with each other. Such software also needs to be supported on a broad range of computer platforms to increase the softwares accessibility. In this paper, the development of world-wide-web based medical consultation system for radiology imaging is addressed to provide platform independence and greater accessibility. The system supports sharing of 3-dimensional objects. We use VRML (Virtual Reality Modeling Language), which is the defacto standard in 3-D modeling on the Web. 3-D objects are reconstructed from CT or MRI volume data using a VRML format, which can be viewed and manipulated easily in Web-browsers with a VRML plug-in. A Marching cubes method is used in the transformation of scanned volume data sets to polygonal surfaces of VRML. A decimation algorithm is adopted to reduce the number of meshes in the resulting VRML file. 3-D volume data are often very large in size, hence loading the data on PC level computers requires a significant reduction of the size of the data, while minimizing the loss of the original shape information. This is also important to decrease network delays. A prototype system has been implemented (http://cybernet5.snu.ac.kr/-cyber/mrivrml .html), and several sessions of experiments are carried out.

Telomerase activity in ductal carcinoma in situ and invasive breast cancer

The increasing number of breast carcinoma in situ detected by screening procedures makes it imperative to develop improved markers to stratify the risk of invasive cancer. Telomerase is detectable in invasive cancer, but not in normal tissues. We have microdissected frozen tissue blocks containing both DCIS and invasive cancer to assay the telomerase activity of these two lesions. The 46 available cases of concurrent DCIS and invasive breast cancer resulted in 43 DCIS samples and 38 invasive cancer samples adequate for analysis. Seventy per cent of the DCIS and all invasive cancer samples tested had detectable telomerase activity. In addition, we analysed telomerase activity in ten cases of DCIS that were not associated with invasive cancer, and detected telomerase activity in seven (70%). Mixing experiments showed no evidence of telomerase inhibitors in telomerase negative samples. Furthermore, periductal inflammatory infiltrates were shown to be a potential confounding source of telomerase activity. Since DCIS lesions appear to be heterogeneous with respect to telomerase activity, and telomerase activation appears to precede the development of invasive cancer, telomerase activity may be a useful adjunct in stratifying the risk of developing invasive breast cancer in patients with DCIS.

Sequential priming in hierarchically organized figures: effects of target level and target resolution

Three experiments are reported in which participants identified target letters that appeared at either the global or local level of hierarchically organized stimuli. It has been previously reported that response time is facilitated when targets on successive trials appear at the same level (L. M. Ward, 1982; L. C. Robertson, 1996). Experiments 1 and 2 showed that this sequential priming effect can be mediated by target-level information alone, independent of the resolution, or actual physical size, of targets. Target level and resolution were unconfounded by manipulating total stimulus size, such that global elements of the smaller stimuli subtended the same amount of visual angle as local elements of the larger stimuli. Experiment 3, however, showed that when level information is less useful than resolution in parsing targets from distractors, resolution does become critical in intertrial priming. These data are discussed as they relate to the role of attention in local vs. global (part vs. whole) processing.

Syntheses of (+/-)-shinflavanone and its structural analogues as potent inhibitors of bone resorption pits formation

The first total syntheses of (+/-)-shinflavanone and its structural analogues were achieved. (+/-)-Shinflavanone, appears to be a strong inhibitor of bone resorption pits formation by osteoclast-like cell induced by 1alpha, 25-dihydroxy vitamine D3 (IC50 = 0.70 microg/mL).

N-(4-bromobenzoyl)-S,S-dimethyliminosulfurane, a potent dermal penetration enhancer

N-Aroyl-, N-Arylsulfonyl-, and N-Aryl-S,S-dimethyliminosulfuranes have been synthesized and evaluated as potential dermal penetration enhancers. The title compound and Azone exhibit similar activities for permeation of hydrocortisone through hairless mouse skin.

Cripto-1 indirectly stimulates the tyrosine phosphorylation of erb B-4 through a novel receptor

Cripto-1 (CR-1) is a recently discovered protein of the epidermal growth factor family that fails to directly bind to any of the four known erb B type 1 receptor tyrosine kinases. The present study demonstrates that CR-1 indirectly induces tyrosine phosphorylation of erb B-4 but not of the epidermal growth factor-related receptors erb B-2 and erb B-3 in different mouse and human mammary epithelial cell lines. In addition, down-regulation of erb B-4 in NMuMG mouse mammary epithelial cells and in T47D human breast cancer cells, using an anti-erb B-4 blocking antibody or a hammerhead ribozyme vector targeted to erb B-4 mRNA, impairs the ability of CR-1 to fully activate mitogen-activated protein kinase. Finally, chemical cross-linking of 125I-CR-1 to mouse and human mammary epithelial cell membranes results in the labeling of two specific bands with a molecular weight of 130 and 60 kDa, suggesting that the CR-1 receptor represents a novel receptor structurally unrelated to any of the known type I receptor tyrosine kinases. In conclusion, these data demonstrate that CR-1, upon binding to an unknown receptor, can enhance the tyrosine kinase activity of erb B-4 and that a functional erb B-4 receptor is required for CR-1-induced MAPK activation.

Physostigmine enhances performance on an odor mixture discrimination test

Acetylcholine is found within key sectors of the olfactory pathway, and is the neurotransmitter for many bulbopetal axons terminating in the glomerular and internal plexiform layers of the olfactory bulb. The present study determined whether systemically administered physostigmine, a cholinesterase inhibitor, alters the rat's ability to discern among odorant mixtures. Following appropriate training, the performance of eight rats was measured every third day on an odor mixture discrimination test with six levels of difficulty. On each test day (separated from one another by 3 days), a different drug treatment was administered [i.e., 0.00 (saline), 0.05, 0.10, or 0.20 mg/kg physostigmine]. The presentation order of the treatments was counterbalanced across subjects using 4 x 4 Latin squares. The mixture discrimination test consisted of discerning the odor of an airstream coming from the saturated head space of a 1% concentration of ethyl acetate from an airstream saturated with a 1% concentration of ethyl acetate and various concentrations of butanol (i.e., 1, 0.5, 0.1, 0.05, 0.01, or 0.005%). Physostigmine was found to enhance odor discrimination performance on the more difficult discrimination tasks in a dose-related manner, suggesting that cholinergic activation may sharpen the ability of rats to discern subtle differences among complex odor stimuli.

Signal transduction in esophageal and LES circular muscle contraction

Contraction of normal esophageal circular muscle (ESO) in response to acetylcholine (ACh) is linked to M2 muscarinic receptors activating at least three intracellular phospholipases, i.e., phosphatidylcholine-specific phospholipase C (PC-PLC), phospholipase D (PLD), and the high molecular weight (85 kDa) cytosolic phospholipase A2 (cPLA2) to induce phosphatidylcholine (PC) metabolism, production of diacylglycerol (DAG) and arachidonic acid (AA), resulting in activation of a protein kinase C (PKC)-dependent pathway. In contrast, lower esophageal sphincter (LES) contraction induced by maximally effective doses of ACh is mediated by muscarinic M3 receptors, linked to pertussis toxin-insensitive GTP-binding proteins of the G(q/11) type. They activate phospholipase C, which hydrolyzes phosphatidylinositol bisphosphate (PIP2), producing inositol 1,4,5-trisphosphate (IP3) and DAG. IP3 causes release of intracellular Ca++ and formation of a Ca++-calmodulin complex, resulting in activation of myosin light chain kinase and contraction through a calmodulin-dependent pathway. Signal transduction pathways responsible for maintenance of LES tone are quite distinct from those activated during contraction in response to maximally effective doses of agonists (e.g., ACh). Resting LES tone is associated with activity of a low molecular weight (approximately 14 kDa) pancreatic-like (group 1) secreted phospholipase A2 (sPLA2) and production of arachidonic acid (AA), which is metabolized to prostaglandins and thromboxanes. These AA metabolites act on receptors linked to G-proteins to induce activation of PI- and PC-specific phospholipases, and production of second messengers. Resting LES tone is associated with submaximal PI hydrolysis resulting in submaximal levels of inositol trisphosphate (IP3-induced Ca++ release, and interaction with DAG to activate PKC. In an animal model of acute esophagitis, acid-induced inflammation alters the contractile pathway of ESO and LES. In LES circular muscle, after induction of experimental esophagitis, basal levels of PI hydrolysis are substantially reduced and intracellular Ca++ stores are functionally damaged, resulting in a reduction of resting tone. The reduction in intracellular Ca++ release causes a switch in the signal transduction pathway mediating contraction in response to ACh. In the normal LES, ACh causes release of Ca++ from intracellular stores and activation of a calmodulin-dependent pathway. After esophagitis, ACh-induced contraction depends on influx of extracellular Ca++, which is insufficient to activate calmodulin, and contraction is mediated by a PKC-dependent pathway. These changes are reproduced in normal LES cells by thapsigargin-induced depletion of Ca++ stores, suggesting that the amount of Ca++ available for release from intracellular stores defines the signal transduction pathway activated by a maximally effective dose of ACh.

Smoking cessation following treatment in a smoke-free Navy Alcohol Rehabilitation program

The purpose of this study was to examine changes in smoking behavior and attitudes following treatment in the smoke-free Navy Alcohol Rehabilitation program (NARC) and to evaluate changes in staff attitudes toward the smoke-free policy. Consecutive patients (N = 404; 93.8% male) admitted to the NARC between February 1, 1993 and September 30, 1993 were studied, of whom 54.7% were current smokers. Measures included patient surveys administered repeatedly at admission and discharge and at 12 months following the 4-week treatment program. The staff were also administered a survey 2 months before (N = 86) and 6 months after (N = 104) policy implementation. Results indicate that alcohol treatment in a smoke-free environment did not markedly affect the smoking status of patients; the proportion of current smokers at discharge was 54.7%. Significant reductions in cigarettes smoked per day (p < .001) were observed among patients from admission to discharge. However, no statistically significant change in readiness to consider smoking cessation scores was detected. Results indicated no significant change in patient smoking status at 12-month follow-up, although the survey response rate was low (35.1%; N = 142). Six months following implementation of the smoke-free policy, 84.6% of staff indicated that the NARC should remain smoke-free and 84.6% recommended that other alcohol and drug treatment facilities be smoke-free.

Immunoglobulin transgenes as targets for somatic hypermutation

This review describes studies on somatic hypermutation of immunoglobulin genes that were started in the mid-80s in collaboration with Ralph Brinster. Almost all of the experiments were carried out using Ig transgenes as targets for the somatic mutation mechanism. Ig transgenes can be very good targets of somatic mutation, despite many different transgene integration sites. Thus, the required cis-acting elements must be present within the approximately 10 kb of the transgene. Only the Ig variable region and its proximate flanks are mutated, not the constant region in unmanipulated sequences. Several Ig gene enhancers are permissive for somatic mutation and they do not have to be associated with the Ig promoter they normally interact with. However, the mutation process does seem to be specific for Ig genes. No mutations were found in several housekeeping genes isolated from cells that had very high levels of somatic hypermutation of their Ig genes. This suggests that the Ig enhancers provide the lg gene specificity. An exception is the Bcl-6 gene, encoding a transcription factor, which was found to be mutated in normal human memory B cells. When the transcriptional promoter that is located upstream of the variable region is duplicated upstream of the constant region, this region is mutated as well. This suggests a transcription coupled model in which a mutator factor associates with the RNA polymerase at the initiation of transcription, travels with the polymerase during elongation, and causes mutations during polymerase pausing. Our recent data with an artificial substrate for somatic mutation suggest that the mutations are increased by increased stability of the secondary structures in the nascent RNA, and the specific nucleotides that are mutated are due to preferences of a mutator factor.

Helicobacter pylori reinfection rate and duodenal ulcer recurrence in Korea

In the short term, the eradication of Helicobacter pylori in patients with duodenal ulcer (DU) is deemed to be clearly effective; the long-term effectiveness apparently depends on the H. pylori reinfection rate. We conducted the present study to investigate the rates of H. pylori reinfection and DU recurrence in 45 patients previously cured of DU in whom H. pylori had been eradicated. These patients underwent gastroscopy and tests for H. pylori at least 1 year after eradication. In a control group comprising 31 patients with DU who were not treated with H. pylori eradication regimen, the DU recurrence rate was checked annually for 4 years. Twenty of 45 patients (44.4%) in whom the mean follow-up period was 3.5 years were again found to be H. pylori positive, and the reinfection rate was 12.8% per year. DU recurred in 8 of these 20 (40%) but not in any nonreinfected patients. In the control group, the DU recurrence rate was 61% within 1 year, 81% within 2 years, 84% within 3 years, and 90% within 4 years. The respective recurrence rates in the 45 patients in whom the bacteria had been eradicated were 0%, 4%, 13%, and 18%. The H. pylori reinfection rate was as high as 12.8% per year in Korea, but in that the DU recurrence rate is significantly lower (p < 0.01; odds ratio, 129.5) in the H. pylori-eradicated group than in the control group, the eradication of H. pylori in DU patients is effective over the long term (at least 4 years).

Thiolated Salmonella antibody immobilization onto the gold surface of piezoelectric quartz crystal

An improved antibody-coated sensor system based on quartz crystal microbalance analysis on Salmonella spp. was developed making use of thiolated antibody immobilization onto one gold electrode of the piezoelectric quartz crystal surface. The best results in sensitivity and stability were obtained with the thin layer of a thiol-cleavable, heterobifunctional cross-linker, sulfosuccinimidyl 6-[3-(2-pyridyldithio)propionamido]hexanoate (sulfo-LC-SPDP). The long bridge of this reagent could function as a spacer, facilitating antibody-Salmonella interaction on the gold electrode. After the addition of a S. typhimurium suspension into a reaction cell with 0.1 M sodium phosphate buffer, pH 7.2, the resonant frequency decreased conspicuously. The time required for maximum frequency shift was about 30-90 min. Sensor response was observed for the microbial suspensions ranging from 9.9 x 10(5) to 1.8 x 10(8) CFU/ml.

Cyanide determination by an ISFET-based peroxidase biosensor

Horseradish peroxidase immobilized on the surface of an Ion Sensitive Field Effect Transistor (ISFET) can be used for the determination of cyanide ions in aquatic media. When the enzyme is immobilized in BSA gel, the resulting sensor can determine 10(-5)-10(-3) M cyanide. Enzyme immobilization into a positively charged polymer, poly(4-vinylpyridine-co-styrene) (PVPy), seems to cause an increase in cyanide inhibition effects because of anion accumulation in the polymeric matrix, and the resulting sensor can measure cyanide concentration in the range 10(-7)-10(-5) M. Fifty percent peroxidase inactivation was observed with 80 microM KCN in the case of BSA-entrapped enzyme, and with only 0.6 microM KCN when the enzyme was covered by PVPy film. Because of the reversible nature of peroxidase inhibition with cyanide ions, restoration of the enzyme activity after inhibition can be obtained by sensor rewashing in fresh buffer.

Long-term effect of Helicobacter pylori eradication on gastric metaplasia in patients with duodenal ulcer

There have been conflicting reports on the effect of Helicobacter pylori eradication on gastric metaplasia in the duodenal bulb (DGM). In the present study, we have investigated the relationships between DGM and H. pylori by examining whether or not H. pylori-positive patients had more DGM than H. pylori-negative patients with nonulcer dyspepsia (NUD) or duodenal ulcer (DU), and by examining the effect of eradication of H. pylori on the prevalence and the extent of DGM during the long-term up to 4 years. Fifty H. pylori-positive and seven H. pylori-negative patients with DU and 23 H. pylori-positive and 23 H. pylori-negative NUD subjects were studied. Two duodenal bulb biopsy specimens were taken for histologic evaluation and the presence and the extent of DGM were evaluated. The extent of DGM was classified as none (grade 0), focal (grade 1), multifocal (grade 2), and diffuse type (grade 4). In H. pylori-positive patients with DU, follow-up gastroscopy was conducted 4 weeks, 1 year, and 4 years after H. pylori eradication. DGM was significantly (p < 0.001) more common (DU: 93%, NUD: 22%) and significantly (p < 0.001) greater in extent for patients with DU than for NUD subjects (DU: 1.89, NUD: 0.28). Neither the prevalence nor the extent of DGM was affected by H. pylori status in patients with DU or NUD; the prevalence (extent) of DGM of H. pylori-positive and -negative patients with DU were 96% (1.94) and 71% (1.57), respectively. In the 43 "H. pylori-eradicated" group, initial prevalence of DGM was 95% and those of 4 weeks, 1 year, and 4 years after eradication were 91%, 96%, and 79%, respectively. The initial extent of DGM was 1.93, and those of 4 weeks, 1 year, and 4 years after eradication were 1.90, 1.88, and 1.57, respectively. In conclusion, the prevalence and the extent of DGM were not related to H. pylori in patients with DU or NUD. In addition, the prevalence and the extent of DGM did not change until 1 year after H. pylori eradication in patients with DU, and decreased to the initial level of the H. pylori-negative DU group but without statistical significance after 4-year follow-up.

Leukotriene D4-induced contraction of cat esophageal and lower esophageal sphincter circular smooth muscle

BACKGROUND & AIMS

In esophageal circular muscle, acetylcholine activates phosphatidylcholine-specific phospholipases C and D and phospholipase A2, producing diacylglycerol and arachidonic acid, which cause contraction by interacting synergistically to activate protein kinase C. In a model of acute esophagitis, leukotriene D4 (LTD4) contributes to acetylcholine-induced contraction. We examined intracellular signaling in LTD4-induced contraction.

METHODS

Esophageal and lower esophageal sphincter (LES) cells, isolated by enzymatic digestion, were contracted by LTD4 in the absence or presence of inhibitors. Permeabilization by saponin allowed use of G-protein antibodies and heparin.

RESULTS

Esophageal contraction was inhibited by pertussis toxin, Gi3 antibodies, D609 (phosphatidylcholine-specific phospholipase C inhibitor), propranolol (phospholipase D pathway inhibitor), and chelerythrine (protein kinase C antagonist) but not W7 (calmodulin antagonist). LES contraction was unaffected by pertussis toxin. It was inhibited by Gq antibodies, U-73122 (phosphatidylinositol-specific phospholipase C inhibitor), heparin (inositol 1,4,5-trisphosphate inhibitor), and W7 and reduced by D609.

CONCLUSIONS

In the esophagus, LTD4 activates a protein kinase C-dependent pathway through pertussis toxin-sensitive Gi3 proteins and phosphatidylcholine-specific phospholipase. In the LES, LTD4 activates a calmodulin-dependent pathway through pertussis toxin-insensitive Gq proteins and phosphatidylinositol-specific phospholipase C. The intracellular pathways activated by LTD4 in the esophagus and the LES are similar to those activated by acetylcholine and other agonists.

Cell cycle and adhesion defects in mice carrying a targeted deletion of the integrin beta4 cytoplasmic domain

The cytoplasmic domain of the integrin beta4 subunit mediates both association with the hemidesmosomal cytoskeleton and recruitment of the signaling adaptor protein Shc. To examine the significance of these interactions during development, we have generated mice carrying a targeted deletion of the beta4 cytoplasmic domain. Analysis of homozygous mutant mice indicates that the tail-less alpha6beta4 binds efficiently to laminin 5, but is unable to integrate with the cytoskeleton. Accordingly, these mice display extensive epidermal detachment at birth and die immmediately thereafter from a syndrome resembling the human disease junctional epidermolysis bullosa with pyloric atresia (PA-JEB). In addition, we find a significant proliferative defect. Specifically, the number of precursor cells in the intestinal epithelium, which remains adherent to the basement membrane, and in intact areas of the skin is reduced, and post-mitotic enterocytes display increased levels of the cyclin-dependent kinase inhibitor p27(Kip). These findings indicate that the interactions mediated by the beta4 tail are crucial for stable adhesion of stratified epithelia to the basement membrane and for proper cell-cycle control in the proliferative compartments of both stratified and simple epithelia.

Ultrasound image texture analysis for characterizing intramuscular fat content of live beef cattle

The primary factors in determining beef quality grades are the amount and distribution of intramuscular fat percentage (IMFAT). Texture analysis was applied to ultrasound B-mode images from ribeye muscle of live beef cattle to predict its IMFAT. We used wavelet transform (WT) for multiresolutional texture analysis and second-order statistics using a gray-level co-occurrence matrix (GLCM) technique. Sets of WT- and GLCM-based texture features were calculated from ultrasonic images from 207 animals and linear regression methods were used for IMFAT prediction. WT-based features included energy ratios, central moments of wavelet-decomposed subimages and wavelet edge density. The regression model using WT features provided a root mean square error (RMSE) of 1.44 for prediction of IMFAT using validation images, while that of GLCM features provided an RMSE of 1.90. The prediction models using the WT features showed potential for objective quality evaluation in the live animals.

Toluene distribution of glue sniffers' biological fluid samples in Korea

We have studied the distribution of toluene in glue sniffers' biological fluid samples by gas chromatography or gas chromatography/mass spectrometry. The determined toluene concentrations ranged from 0.1 to 40.3 mg/L in urine samples and from 0.1 to 74.7 mg/L in blood samples, respectively. Among the 120 urine samples, 61% of all cases ranged between 0.1 and 1.0 mg/L and 27% was between 1.0 and 5.0 mg/L, respectively. On the other hand, 39% and 46% of all 99 blood samples ranged between 0.1 and 1.0 mg/L, or 1.0 and 5.0 mg/L, respectively. In the fatal cases (36 cases), the distribution of toluene ranged from 0.3 to 40.5 mg/L in the blood samples.