Reflex rhinorrhea after a right caudate infarct

After a right caudate infarct, a 57-year-old man developed a left reflex rhinorrhea induced by gustation. Since data from the blink reflex and facial electrodiagnosis were normal, a disinhibitory response from caudate nucleus to superior salivatory nucleus is proposed.

[Typing of H. pylori strains isolated from patients with gastric diseases]

Helicobacter pylori, an organism recently described in association with gastritis and peptic lesions. The degree of relationship between these micro-organisms was studied on molecular level using SDS-PAGE protein profiles and immunoblot patterns. Study on a total of 112 lysates of H. pylori showed some differences in protein patterns of different H. pylori strains. However, the difference became more apparent when studied by immunoblot analysis. According to SDS-PAGE protein, strains isolated from gastric mucous of the patients were identified as types I-IV, while type IV can be further classified as sub-type IV-1 to IV-5 analysis of SDS-PAGE protein patterns proved to be an excellent method of characterizing those H. pylori, different from traditional methods.

Lack of embryotoxicity of fumonisin B1 in New Zealand white rabbits

Fumonisin B1 (FB1) is one of a number of mycotoxins produced by fungi, especially Fusarium sp. As a contaminant of many maize-derived products, this toxin is associated with a variety of animal diseases, including esophageal cancer and possibly neural tube defects in humans. We have investigated the embryotoxic potential of this compound in New Zealand White rabbits. Animals were dosed by gavage daily on GD 3-19 with purified FB1 at 0.10, 0.50, or 1.00 mg/kg/day. Maternal lethality occurred at the 0.50 and 1.00 mg/kg/day doses. When examined on GD 29, there were no differences in maternal body weight, maternal weight gain, maternal organ weights, number of nonlive implantations, and number of malformations. Fetal weight was decreased at 0.50 and 1.00 mg/kg/day (13 and 16%, respectively); this was true for male and female pups. Fetal liver and kidney weights were also decreased at these doses. Analysis of embryonic sphinganine to sphingosine ratios demonstrated no differences between control and treated embryos on GD 20, although these ratios were increased in maternal urine, serum, and kidney when compared to control animals. These data suggest that FB1 did not cross the placenta and that the observed decreased fetal weight was probably the result of maternal toxicity, rather than any developmental toxicity produced by FB1.

Inhibition of bufalin on pituitary and testicular function in rats

The effects of bufalin on the secretion of testosterone and luteinizing hormone (LH) and the accumulation of testicular adenosine 3':5'-cyclic monophosphate (cAMP) were studied. Male rats were injected with bufalin, human chorionic gonadotropin (hCG), gonadotropin releasing hormone (GnRH), hCG plus bufalin or GnRH plus bufalin via a jugular catheter. Blood samples were collected at several intervals subsequent to the challenge. In the in vitro study, rat testis blocks were incubated with bufalin, hCG or both for 1 h. The anterior pituitary gland was incubated with bufalin, GnRH or both for 30 min. The media were analyzed for testosterone or LH. For studying cAMP accumulation, testicular blocks were incubated for 1 h with the medium containing isobutyl-1-methylxanthine. After incubation, tissues were extracted by ethanol before measuring cAMP concentration. A single intravenous injection of bufalin decreased the basal and hCG-stimulated levels of plasma testosterone. Administration of bufalin in vitro resulted in an inhibition of both basal and hCG-stimulated release of testosterone. Bufalin diminished cAMP accumulation in rat testes. However, the basal levels of plasma and medium LH were not altered by bufalin administration. Likewise, the LH response to GnRH was diminished by bufalin administration, both in vivo and in vitro. These results suggest that the inhibition of testosterone production by bufalin is partly caused by a decrease of testicular cAMP accumulation and LH response to GnRH in rats.

The role of cyclic AMP production, calcium channel activation and enzyme activities in the inhibition of testosterone secretion by amphetamine

1. The aim of this study was to investigate the mechanism by which amphetamine exerts its inhibitory effect on testicular interstitial cells of male rats. 2. Administration of amphetamine (10(-12)-10(-6) M) in vitro resulted in a dose-dependent inhibition of both basal and human chorionic gonadotropin (hCG, 0.05 iu ml(-1))-stimulated release of testosterone. 3. Amphetamine (10(-9) M) enhanced the basal and hCG-increased levels of adenosine 3':5'-cyclic monophosphate (cyclic AMP) accumulation in vitro (P<0.05) in rat testicular interstitial cells. 4. Administration of SQ22536, an adenylyl cyclase inhibitor, decreased the basal release (P<0.05) of testosterone in vitro and abolished the inhibitory effect of amphetamine. 5. Nifedipine (10(-6) M) alone decreased the secretion of testosterone (P<0.01) but it failed to modify the inhibitory action of amphetamine (10(-10)-10(-6) M). 6. Amphetamine (10(-10)-10(-6) M) significantly (P<0.05 or P<0.01) decreased the activities of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), P450c17, and 17-ketosteroid reductase (17-KSR) as indicated by thin-layer chromatography. (t.l.c.). 7. These results suggest that increased cyclic AMP production, decreased Ca2+ channel activity and decreased activities of 3beta-HSD, P450c17, and 17-KSR are involved in the inhibition of testosterone production induced by the administration of amphetamine.

The visible vessel on the bleeding gastric ulcer: an endoscopic-pathological study

BACKGROUND AND STUDY AIMS

The visible vessel is an important endoscopic sign for predicting rebleeding in ulcers. Freeman has described a visible vessel with a high rate of rebleeding as a "pearl" color (whitish) compared with a darkly colored "sentinel" clot with a low rebleeding rate. Clarifying the color of visible vessels helps to distinguish high-risk bleeding ulcers. We conducted a retrospective study that compared pathological findings with endoscopic pictures to determine the significance of the visible vessel's color.

PATIENTS AND METHODS

From January 1986 to December 1992, 110 patients who underwent endoscopy and received subtotal gastrectomies for ulcer bleeding were included in this study. Of these, 24 received endoscopic therapy before the operation. There were 94 males and 16 females, ranging in age from 30 to 90 years, with a mean age of 62.5 years. According to Freeman's report, a subgroup of visible vessels (IIav +) was defined as having either a "pearl-colored" collar around a red or black protruding mount or a "pearl-colored" mount on the ulcer base. The endoscopic findings were compared with the findings of the pathological specimens.

RESULTS

The endoscopic findings on the stigmata of recent hemorrhage in the 110 patients revealed that 31 were of type IIa (including 18 type IIav+ and 13 type IIav-), 56 of type IIb, 18 of type IIc, and 5 of type III. Fifty-four patients (49,1%) were found from their pathological specimen to have an eroded vessel on their ulcer base. Type IIa patients had a higher percentage of eroded vessels. The percentages of eroded vessels in types IIa, IIb, IIc, and III were 67.7%, 46.4%, 33.3%, and 20 %, respectively (P < 0.05, Fisher's exact test). Of the 54 patients with an eroded vessel in their pathological specimen, 13 (24 %) were found to have some vessel wall above the ulcer base (six in type IIa, four in type IIb, two in type IIc, and one in type III). Among the six with vessel wall above the ulcer base in type IIa, five patients (83 %) were identified as type IIav+ under endoscopy. There was a greater frequency of having a vessel wall above the ulcer base in type IIav+ than in type IIav- (38.5% vs. 12.5%) among the 31 endoscopic type IIa patients.

CONCLUSION

From this study, we determined that the wall of an eroded vessel on a gastric ulcer may protrude either above or below the ulcer base. A vessel wall on the ulcer base will appear pearl-colored under endoscopic view.

Multiple muscle-specific regulatory elements are associated with a DNase I hypersensitive site of the cardiac beta-myosin heavy-chain gene

Using nuclei isolated from neonatal cardiomyocytes, we have mapped the DNase I hypersensitive sites (DHSs) residing within the 5'-upstream regions of the hamster cardiac myosin heavy-chain (MyHC) gene. Two cardiac-specific DHSs within the 5 kb upstream region of the cardiac MyHC gene were identified. One of the DHSs was mapped to the -2.3 kb (beta-2.3 kb) region and the other to the proximal promoter region. We further localized the beta-2.3 kb site to a range of 250 bp. Multiple, conserved, muscle regulatory motifs were found within the beta-2.3 kb site, consisting of three E-boxes, one AP-2 site, one CArG motif, one CT/ACCC box and one myocyte-specific enhancer factor-2 site. This cluster of regulatory elements is strikingly similar to a cluster found in the enhancer of the mouse muscle creatine kinase gene (-1256 to -1050). The specific interaction of the motifs within the beta-2.3 kb site and the cardiac nuclear proteins was demonstrated using gel mobility-shift assays and footprinting analysis. In addition, transfection analysis revealed a significant increase in chloramphenicol acetyltransferase activity when the beta-2.3 kb site was linked to a heterologous promoter. These results suggest that previously undefined regulatory elements of the beta-MyHC gene may be associated with the beta-2.3 kb site.

Mutational analysis of transcriptional activation by the bovine papillomavirus type 1 E6

While the bovine papillomavirus type 1 (BPV-1) E6 induces tumorigenic transformation of murine C127 cells, it does not bind or promote the degradation of p53. We recently showed the cellular protein ERC-55/E6BP binds BPV-1 E6 as well as the cancer-related human papillomavirus (HPV) E6 proteins. BPV-1 E6 also binds E6-AP, a ubiquitin ligase necessary for HPV E6-induced p53 degradation. We previously reported that the transforming activity of a set of BPV-1 E6 mutants correlated with their E6BP-binding ability. Another function of BPV-1 E6 is stimulation of transcription when targeted to a promoter, although cellular promoters responsive to BPV-1 E6 have not been identified. To examine whether its transcriptional function is required for oncogenic activity, or is related to its interactions with E6-AP or E6BP, a series of BPV-1 E6 mutants were analyzed as fusions to a sequence-specific DNA binding domain for activity in yeast and in mammalian cells. We show that some transformation defective mutants retained substantial levels of transcriptional activation activity. These mutants also distinguish transcriptional activation from E6-AP and E6BP binding. These results suggest the transcriptional activation function of BPV-1 E6 is not sufficient for cell transformation.

Influence of sampling on the reproducibility of ovarian follicle counts in mouse toxicity studies

Different ovarian follicle counting procedures were investigated to reduce labor while retaining statistical power. Intact ovaries of untreated CD-1 mice (20/group) from National Toxicology Program Reproductive Assessment by Continuous Breeding (RACB) studies were serially sectioned at 6 microm. Mean numbers of small and growing follicles were used to assess sampling efficiency. In 10 mice per group, comparisons were made between 10% nonrandom samples from every 10th section starting at either the first or sixth section having follicles (approximately 40 sections per ovary). These 10% counts were compared with 5% (20 sections) and 20% (80 sections) nonrandom samples and with 1% (4 sections), 5%, or 10% random samples from the same 10 animals. For two studies, a 10% nonrandom sample was analyzed from 20 mice per group. Follicle counts for each group were comparable regardless of the sampling paradigm. Four to 10 animals provided 90% confidence that a 20% difference in mean counts would be detected. The 1% sample had a larger error term and, thus, slightly reduced statistical power. These data suggest that follicle counts from 1% or 5% random samples may provide a suitable screen for ovarian toxicity.

Differential follicle counts as a screen for chemically induced ovarian toxicity in mice: results from continuous breeding bioassays

Ovaries from National Toxicology Program Reproductive Assessment by Continuous Breeding (RACB) bioassays were used to directly compare differential ovarian follicle counts and reproductive performance for 15 chemicals. Ovaries of 10 animals per group from 16 studies in CD-1 mice and 1 study each in C3H and C57BL/6 mice were sectioned serially at 6 microm. Counts of small, growing, and antral follicles were obtained in every 10th section. For all follicle types, younger mice had more follicles than older mice, and CD-1 mice had more follicles than age-matched animals from either inbred strain. The in-life portion of the RACB protocols demonstrated that 9 of 15 chemicals altered reproductive outcome in one or both sexes of mice, with six agents affecting females (R. E. Morrissey et al., 1989, Fundam. Appl. Toxicol. 13, 747-777). Three of six female toxicants [2,2-bis(bromoethyl)-1,3-propanediol, BPD; ethylene glycol monomethyl ether, EGME; methoxyacetic acid, MAA] significantly decreased counts of small and/or growing follicles by 33 to 92% in CD-1 mice; EGME also reduced follicle counts in the other strains. Follicle counts were decreased in progeny of animals treated with EGME or its active metabolite, MAA. For BPD, reductions in follicle numbers were proportional to dose. In CD-1 mice, female toxicants di-N-hexyl phthalate, propantheline bromide, and tricresyl phosphate reduced reproductive performance but not follicle numbers. Counts were not affected by toxicants for which the susceptible sex could not be determined (bisphenol A, ethylene glycol, oxalic acid). Altered follicle counts without apparent reproductive impairment occurred in CD-1 mice at lower doses of BPD but were not observed for nontoxic chemicals. These data suggest that differential follicle counts (1) are a quantifiable endpoint of ovarian injury in conventional bioassays, and (2) in some instances, may provide a more sensitive indicator of female reproductive toxicity than fertility.

Adenocarcinoma in the middle third of the stomach--an evaluation for the prognostic significance of clinicopathological features

BACKGROUND/AIMS

The prognosis of patients with gastric adenocarcinoma varies with the location of the tumor. Adenocarcinoma in the middle third of the stomach has been claimed to have a better outcome than those in other locations. However, there is still very limited information specifically regarding the prognostic factors which influence the survival time of patients with adenocarcinoma in the middle third of the stomach. This retrospective study was designed with the aim to evaluate and uncover the possible significant clinicopathological parameters for adenocarcinoma in the middle third of the stomach.

METHODOLOGY

Between 1986 and 1992, 363 patients underwent gastric resection for primary gastric adenocarcinoma at this hospital. Fifty-two (14.3%) of these patients were included in this study and they all met the following criteria: 1) tumor primarily located in the middle third of the stomach without distant metastases or peritoneal seeding, 2) undergoing curative resection and 3) undergoing R2 nodal dissection, at least. The clinicopathological findings were obtained by detailed review of the medical records and the histologic slides. All surviving patients were also contacted and their current conditions were recorded.

RESULTS

The overall 5-year survival rate (Kaplan-Meier method) was 42.5%. In univariate survival analysis by Kaplan-Meier method and long-rank test, serosal invasion (p < 0.01), lymph node metastasis (p < 0.01) and lymphatic involvement (p < 0.01) had an individual prognostic significance. When a multivariate analysis using Cox proportional hazards regression was performed, serosal invasion (P < 0.01) and lymphatic involvement (p < 0.05) appeared as the only two independent prognostic factors regarding long-term survival. When these 52 patients were categorized into patients with early gastric cancer (n = 10) and patients with advanced gastric cancer (n = 42), there was a significant difference (p < 0.01) between the survival rates (90.0% vs. 29.1%). When these tumors were further categorized into early gastric cancer (n = 10), early simulating advanced gastric cancer (n = 14) and Borrmann type advanced gastric cancer (n = 28), there were significant differences (P < 0.01 and P < 0.01, respectively) in 5-year overall survival rates between early gastric cancer (90.0%) and Borrmann type advanced gastric cancer (18.9%), also between early simulating advanced gastric cancer (52.5%) and Borrmann type advanced gastric cancer (18.9%). UICC stage also had significant influence (P < 0.01) on the survival rates.

CONCLUSIONS

Serosal invasion and lymphatic involvement are the significant, independent prognostic factors in predicting the survival rate of patients with adenocarcinoma in the middle third of the stomach. Since more advanced stage tumors usually carry a poorer prognosis, early detection is of extreme importance for improving the survival rate.

Catalase mediates acetaldehyde formation from ethanol in fetal and neonatal rat brain

Fetal ethanol (E) exposure has well documented deleterious effects on brain development, yet it is uncertain if the neurotoxicity of maternal E consumption is generated by E itself, by its primary metabolite acetaldehyde (AcHO), or both. The current studies present evidence that homogenates of immature rat brains can generate AcHO via a catalase (CAT)-mediated reaction and that AcHO may be produced in vivo by this system. Homogenates of day 19 fetal rat brain were incubated with E (50 mM). When incubated with CAT inhibitors (sodium azide or 3-aminotriazole), AcHO formation was blocked, whereas neither the alcohol dehydrogenase inhibitor, 4-methylpyrazole, nor P-450 inhibitors decreased AcHO production. Three hours after one oral dose of E (4 g/kg) to a pregnant dam (gestation day 19), AcHO levels in fetal brain increased to 14.28 +/- 1.82 nM/g tissue. Baseline CAT activity in day 19 fetal brains was 4.5 times adult values (p < 0.05). Western blot analysis determined that CAT protein level in the day 19 fetal brain exceeded that in adult brain by 2.5 times. One hour after a single dose of E, CAT activity in day 19 fetal brain increased by 8.2 units/mg protein. In 5-day-old neonatal brains during the "third trimester" brain growth spurt, baseline CAT activity was twice the adult values (p < 0.05) and a 2-day in vivo E regimen increased AcHO levels to four times the control values, with a concomitant 1.7-fold increase in CAT activity. This was prevented by administration of a CAT inhibitor (3-amino-1,2,4-triazole). Immunohistochemical staining of neonatal brains exposed to E illustrated the presence of acetaldehyde-protein adducts. We conclude that AcHO is likely produced in rat fetal and neonatal brain via CAT-mediated oxidation of E. This phenomenon may be an important factor in the neurotoxic effects of in utero E exposure.

Lactate and the effects of exercise on testosterone secretion: evidence for the involvement of a cAMP-mediated mechanism

The effects of swimming and lactate on the release of testosterone were examined in male rats. During in vivo experiments, male rats were catheterized via the right jugular vein and blood was collected at 0, 10, 15, 30, and 60 min following the exercise, or they were catheterized via the right jugular vein and the left femoral vein and blood was collected at 0, 2, 5, 10, 15, 30, 60, and 120 min after a 10-min infusion at lactate (13 mg.kg-1.min-1). Trunk blood and blood from the testicular vein were also collected after 10 min of swimming or water immersion. In an in vitro experiment, testicular fragments were challenged with lactate (0.01-10 mM) and/or human chorionic gonadotropin (hCG; 0.5 IU.mL-1), and the mediobasal hypothalamus (MBH) was challenged with lactate (8 mM). The post-exercise levels of plasma lactate and testosterone at 10, 15, and 30 min were higher than resting levels. Plasma luteinizing hormone (LH) was increased following 30 min of swimming. Administration of lactate or hCG increased in a dose dependent manner testicular cyclic adenosine 3':5' monophosphate (cAMP) and testosterone release. Plasma testosterone increased after swimming and lactate infusion. Incubation of MBH with lactate increased the gonadotropin-releasing hormone (GnRH) level in the medium. These results suggest that the increased plasma testosterone levels in male rats during exercise is at least partially a result of a direct and LH-independent stimulatory effect of lactate on the secretion of testosterone by increasing testicular cAMP production. Swim-elevated plasma LH may be a result of a rise of GnRH caused by lactate.

A gene fusion at a homeobox locus: alterations in leaf shape and implications for morphological evolution

Compound leaves are seen in many angiosperm genera and are thought to be either fundamentally different from simple leaves or elaborations of simple leaves. The knotted1-like homeobox (knox) genes are known to regulate plant development. When overexpressed in homologous or heterologous species, this family of genes can cause changes in leaf morphology, including excessive leaf compounding in tomato. We describe here an instance of a spontaneously arisen fusion between a gene encoding a metabolic enzyme and a homeodomain protein. We show that the fusion results in overexpression of the homeodomain protein and a change in morphology that approximates the changes caused by overexpression of the same gene under the control of the cauliflower mosaic virus 35S promoter in transgenic plants. Exon-shuffling events can account for the modularity of proteins. If the shuffled exons are associated with altered promoters, changes in gene expression patterns can result. Our results show that gene fusions of this nature can cause changes in expression patterns that lead to altered morphology. We suggest that such phenomena may have played a role in the evolution of form.

The effects of pyrroloquinoline quinone on heme-regulated eIF-2alpha kinase and eIF-2B activities in eukaryotic protein synthesis

Pyrroloquinoline quinone (PQQ), a novel cofactor of biological redox processes, is ubiquitous in animal cells. We have examined the effects of PQQ on protein synthesis. PQQ inhibits protein synthesis in hemin-supplemented rabbit reticulocyte lysates. This inhibition is characterized by increased phosphorylation of eIF-2alpha and by diminished guanine nucleotide exchange activity of eIF-2B. The increased eIF-2alpha phosphorylation is the result of activation by PQQ of the heme-regulated eIF-2alpha kinase (HRI). The addition of 10 microM PQQ completely inhibits the increase in protein synthesis that occurs on the addition of hemin (20 microM) to heme-deficient lysates, whereas a lower concentration of PQQ (100 nM) causes a very slight stimulation of protein synthesis. The increased eIF-2alpha phosphorylation that occurs at high concentrations of PQQ inhibits eIF-2B activity, presumably due to formation of a 15S complex [eIF-2(alphaP).eIF-2B] in which eIF-2B becomes non-functional. Low concentrations of PQQ (0.1-1 microM) do not affect eIF-2alpha phosphorylation, but rather enhance the guanine nucleotide exchange activity of eIF-2B in reticulocyte lysates. In Chinese hamster ovary cell extract which is devoid of significant eIF-2alpha kinase activity, addition of both low and high concentrations of PQQ results in an increase in eIF-2B activity. The addition of PQQ to reticulocyte lysates activates HRI whereas addition of PQQ to purified HRI in vitro inhibits the autokinase and eIF-2alpha kinase activity of the HRI; the inhibition of purified HRI by PQQ is observed both in the presence and absence of hemin. These findings suggest that PQQ inhibits purified HRI by acting as an oxidant whereas in lysates in which PQQ is readily reduced, the PQQ acts as a reductant and increases the activities of both HRI and eIF-2B.

Spatio-temporal representation of multichannel EMG firing patterns and its clinical applications

Analyzing motor unit (MU) activity is essential for studying the neurological dysfunction of upper motor neuron disorders (UMND). This study employs multichannel surface electromyographic (EMG) signals, as recorded from the upper arm during elbow flexion and extension, to analyze the temporal changes and spatial distribution of the dominant firing rate. To estimate the dominant firing rate, the autoregressive (AR) spectrum analysis method is utilized to detect the peaks and poles of the AR model, of the surface EMG spectrum below 40 Hz. The temporal changes in firing rates are also observed by using the spectrogram representation of low-frequency EMG spectra. The EMG spectrogram facilitates examination of the time-varying characteristics of firing rates and recruitment of MUs from surface EMG signal. The low-frequency spectra of multichannel EMG are then represented in a polar form to visualize the spatial distribution of firing patterns across muscles. Via spatio-temporal representation techniques, this study provides a viable approach of observing both the spatial and temporal patterns of MU activities in normal subjects and patients with UMND, including cerebrovascular disease and Parkinson's disease.

Multipoint dissolution specification and acceptance sampling rule based on profile modeling and principal component analysis

In dissolution testing, multiple dissolution measurements at specific time points are needed in quality control when the compliance of the product requires controlled dissolution throughout the time course. The dissolution specification based on general multivariate confidence region was proposed by Chen and Tsong (8). This paper presents two alternative procedures when the dissolution profile consists of important measurements at more than 4 time points. In the first procedure, when the dissolution profile can be described by a physical curve through modeling, the dissolution specification is developed based on the confidence region of the parameters of the physical curve. In the second procedure, the principal components (PCS) as the linear combinations of the dissolution measurements are identified and dissolution specification is set based by the confidence intervals of the values of principal components. In both approaches the specification can be set at lower dimensions than the general multivariate confidence region approach. A single-stage acceptance rule can be used in both approaches by first projecting the dissolution values of each tablet in the new testing batch onto the determined parameters axes (through modeling in modeling approach and through projection on the selected PCS in principal component approach). Then check if the projections of the new tablet fall within the specifications. Finally, count the number of tablets that fall outside the specification limits and reject the batch if the proportion of out-of-specification tablet is high and accept the lot for release if the proportion is low.

Cytotoxic lignans from Formosan Hernandia nymphaeifolia

A new dibenzylbutyrolactone lignan, (--)-6-hydroxyyatein, along with two new furanoid lignans, (--)-hernone [(2R,3S,4R)-(--)-3-hydroxymethyl -4-(3",4",5"-trimethoxybenzoyl)-2-(3,4-dimethoxyphenyl) tetrahydrofuran] and (--)-nymphone [(2R,3S,4R)-(--)-3-hydroxymethyl-4-(3",4",5"-trimethoxybenzoyl)-2- (3,4-methylenedioxyphenyl)tetrahydrofuran], have been isolated and characterized from the trunk bark of Formosan Hernandia nymphaeifolia. The structures of these compounds were determined by means of spectral analyses. These three lignans exhibited cytotoxic activities against P-388, KB16, A549 and HT-29 cell lines.

Bioavailability of selenium from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine, and sodium selenite assessed in selenium-deficient rats

The bioavailability of selenium (Se) from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine (SeMet), and sodium selenite was assessed in Se-deficient Fischer-344 rats. Se as veal, chicken, beef, pork, lamb, flounder, tuna, SeMet, and sodium selenite was added to torula yeast (TY) basal diets to comprise Se-inadequate (0.05 mg Se/kg) diets. Se as sodium selenite was added to a TY basal diet to comprise a Se-adequate (0.10 mg Se/kg), Se-control diet. The experimental diets were fed to weanling Fischer-344 rats that had been subjected to dietary Se depletion for 6 wk. After 9 wk of the dietary Se repletion, relative activity of liver glutathione peroxidase (GSHPx) from the different dietary groups compared with control rats (100%) was: flounder 106%, tuna 101%, pork 86%, sodium selenite 81%, SeMet 80%, beef 80%, chicken 77%, veal 77%, and lamb 58%. Se from flounder was the most efficient at restoring Se concentrations in the liver and skeletal muscle. Se from sodium selenite, SeMet, beef, veal, chicken, pork, lamb, and tuna was not dietarily sufficient to restore liver and muscle Se after 9 wk of recovery following a 6-wk period of Se depletion.

Liver transplantation for hepatitis C-associated cirrhosis in a single Australian centre: referral patterns and transplant outcomes

During the study period, 63 patients with hepatitis C virus (HCV) cirrhosis were referred to our unit for liver transplantation. All cases referred and transplanted were retrospectively examined. Eighty-six per cent of referred patients were male, 35% consumed alcohol in the harmful/hazardous range, 13% were infected with hepatitis B and 7% had hepatocellular carcinoma. Patients with sporadic infection were more likely to be born outside Australia and were an average of 10 years older than those with HCV acquired via intravenous drug use (P < 0.001). However, patients were an average of 12 years younger at referral if they consumed harmful amounts of alcohol than if they abstained (P = 0.002). We examined the impact of HCV on the outcome of 28 patients who underwent liver transplantation (mean follow up 25 months; range 3-76 months). The use of OKT3, HCV genotype and hepatitis B status were examined for their effect on HCV-related graft dysfunction. Three year survival was 84%, equivalent to a control group. Chronic HCV-related graft dysfunction occurred in 15 (56%) patients, of whom 10 had an asymptomatic elevation in serum amino transferase, two had cholestatic hepatitis and three had severe hepatitis C that progressed onto chronic rejection. Hepatitis C virus genotype 1b tended to be associated with HCV graft dysfunction (5/6 type 1b vs 10/16 in non-type 1b). In conclusion, HCV is an increasingly common indication for liver transplantation. Alcohol and hepatitis B were frequently occurring cofactors in the referral cohort. Most patients referred were male, although the reason why is not clear. Transplantation offers a good medium-term outcome, despite the high incidence of HCV-associated graft dysfunction.

Applying fuzzy logic to control cycling movement induced by functional electrical stimulation

This study examines the design of a rational stimulation pattern for electrical stimulation and a robust closed-loop control scheme to improve cycling system efficacy for subjects with paraplegia. The stimulation patterns were designed by analyzing gravitation potential needed for the cycling movement of the lower limbs against a frictionless cycling ergometer and the response delay of electrically stimulated muscles. To simplify the cycling control system, the stimulation patterns were fixed and only the single gain of the stimulation patterns was adjusted via a feedback control algorithm. To circumvent the complexity involved with exactly modeling a stimulated muscle and cycling ergometer, a model-free fuzzy logic controller (FLC) was adopted herein for our control scheme. Comparison between FLC and conventional proportional-derivative (PD) controllers demonstrated that the FLC with asymmetrical membership function enabled the subject with paraplegia to maintain varied desired cycling speeds, particularly at lower cycling speed. By incorporating the rational stimulation patterns, the FLC can produce a smooth and prolonged cycling movement deemed necessary for designing various training protocols.

The role of the 90-kDa heat-shock protein and its associated cohorts in stabilizing the heme-regulated eIF-2alpha kinase in reticulocyte lysates during heat stress

The heme-regulated eIF-2alpha kinase (HRI) is activated not only in heme-deficient rabbit reticulocyte lysates (RRL), but also in hemin-supplemented RRL treated with heat-shock, N-ethylmaleimide (MalNEt) or heavy metal ions. We have demonstrated previously that heat-shock proteins, Hsp90, Hsp70 and FKBP52, are associated with HRI in RRL; the association of HRI with Hsp90 and FKBP52, but not Hsp70, is enhanced by hemin. To study the role of Hsp90 and its associated cohorts in the regulation of HRI, we examined the interaction of these proteins with HRI in hemin-supplemented RRLs during heat or oxidative stress. The association of HRI with Hsp90, FKBP52 and p23 was maintained in heat-, MalNEt- or Hg2(+)-treated hemin-supplemented RRL. Glycerol gradient centrifugation and gel filtration on Sephacryl S-300 indicated that neither heat shock nor MalNEt-treatment affected the apparent molecular mass of HRI in hemin supplemented RRL. In addition, active HRI was coimmunoprecipitated with 8D3 anti-Hsp90 from both heme-deficient and MalNEt-treated hemin-supplemented RRL. These results demonstrate that activation of HRI in response to heat stress and oxidative stress does not require dissociation of Hsp90 from HRI. Furthermore, HRI activity was inhibited upon addition of hemin to Hsp90-depleted heme-deficient RRL, indicating that inhibition of HRI activity by hemin is not mediated by the reassociation of Hsp90 with HRI. We also examined the dynamics of the interaction of Hsp90 with HRI. Reconstitution of the interaction of Hsp90 with HRI was stimulated by elevated temperature and required both Mg2+ and ATP. Addition of purified Hsp90 to hemin-supplemented RRL which had been treated with MalNEt to inactivate its capacity to chaperone protein renaturation, protected HRI from irreversible denaturation and aggregation upon incubation at 41 degrees C. Our results suggest that Hsp90 interacts with HRI primarily in its capacity as a molecular chaperone, stabilizing HRI from denaturation under conditions of heat stress and oxidative stress.

The validity of stimulus-evoked EMG for studying muscle fatigue characteristics of paraplegic subjects during dynamic cycling movement

The fatigue characteristics of paralyzed muscles were investigated during dynamic cycling movement induced by functional electrical stimulation (FES). The peak-to-peak (PTP) amplitude of stimulus-evoked electromyogram (EMG), after suppression of stimulus artifact, was adopted as fatigue indicator. Compared to static contraction, the effects of dynamic movement factors on the stimulus-evoked EMG, such as the intermittent stimulation, joint angle, and contraction speed, were first evaluated in separate experiments. The results of isolated tests laid the foundation for interpreting the data obtained in two FES-cycling experiments, performed under maximum stimulation or in controlled cycling speeds. The effects of intermittent stimulation and joint angle caused periodic changes in PTP amplitude which can be alleviated by averaging the PTP amplitude of one cycle. Under the same stimulation intensity, our results indicated that slower muscle contraction speed would have larger PTP amplitude and vice versa. For the limited number of subjects with paraplegia studied, our results showed that the use of EMG PTP as reliable muscle fatigue indicator during dynamic movement is only valid at the same cycling speed or corresponding contraction speed. The decline of the PTP amplitude decreased with the decay of muscle force can be observed during cycling movement; however, reduction of cycling speed had the opposite effect on PTP amplitude. Observations from the hyperbolic modeling of fatigue process demonstrated that the EMG PTP of a fatigued muscle under dynamic movement decreased at a slower rate.

Tree-structured logistic models for over-dispersed binomial data with application to modeling developmental effects

This article proposes tree-structured logistic regression modeling for over-dispersed binomial data. Recursive partitioning is performed using a combination of statistical tests and residual analysis. The splitting criterion in cross-validation is based on the deviance function. A nested grid algorithm to estimate the bootstrap parameters is developed. The regression tree procedure provides a new approach for exploring in detail the relationship between the binomial response and explanatory variables. The proposed procedure is used to model the relationship between the incidence of malformation and dose and fetal weight using data from a developmental experiment conducted at the National Center for Toxicological Research. A conditional Gaussian chain model is used to account for the effect of fetal weight by dose.