GABA(A) receptor-mediated inspiratory termination evoked by vagal stimulation in decerebrate cats.

To identify the GABAergic inhibitory mechanisms involved in inspiratory termination or off-switching (IOS), the effects of a specific enhancer of GABA(A) receptors, midazolam, and an antagonist, bicuculline, on vagally evoked inspiratory inhibitions and IOS were investigated in decerebrate cats. Stimulation of vagal afferents at late inspiration provoked either reversible inspiratory inhibition or IOS, depending on the stimulus intensity. Each response occurred at a constant latency (phase 1). The reversible response was triphasic, consisting of an early (phase 2) inhibition, a brief (phase 3) excitation and a late (phase 4) inhibition in the phrenic neurogram, and early (phase 2) IPSPs, brief (phase 3) EPSPs and late (phase 4) IPSPs in bulbar inspiratory (I) neurones. With an increasing stimulus intensity, phase 4 inhibitions were increased in amplitude and duration, leading to IOS. Midazolam (0.1 mg/kg i.v.) increased more selectively phase 4 IPSPs than phase 2 IPSPs in I neurones, and decreased the threshold for evoking IOS by producing an earlier and larger phase 4 IPSPs. Bicuculline (1.0 mg/kg i.v.) had an opposite effect. These results suggest that the late inhibitory response evoked by vagal stimulation in the I neuronal pool organizes an initial phase of IOS which is mediated by GABA(A) receptors.     

Effects of ethyl alcohol administration to rat dams during the gestation period on learning behavior and on levels of monoamines and metabolites in rat pup brain after birth

Pregnant rats were given 0%-, 5%-, 10%- and 20% ethyl alcohol in drinking water during the gestation period.We evaluated the brain function of pups born of alcohol-administered dams. Learning ability (Sidman avoidance behavior), the amounts of monoamines (noradrenalin, dopamine, serotonin) and metabolites (3,4-dihydroxyphenyl acetic acid [DOPAC], homovanillic acid [HVA] and 5-hydroxyindole acetic acid [5-HIAA])in whole brain were examined for neurobehavioral and neurochemical effects.There was no effect on Sidman avoidance behavior in 56-day-old offspring, but alterations of the amounts of monoamines and their metabolites were observed even in 66-day-old offspring as a result of the dams' exposure to ethanol during pregnancy.     

Prognostic Significance of Proliferating Cell Nuclear Antigen (PCNA) in Squamous Cell Carcinoma of the Esophagus

Proliferating cell nuclear antigen (PCNA) has been shown tobe of prognostic significance in some gastrointestinal tumors.Immunohistochemical analysis was performed to determine whetherPCNA is useful for predicting the outcome of patients with squamouscell carcinoma of the esophagus. Using a mouse monoclonal antibody,PC 10, the expression of PCNA was studied in resected squamouscell carcinomas of the esophagus from 59 patients who had undergonecurative esophagectomy. None had received any preceding therapy.The proliferation rate was assessed in terms of the percentageof the PCNA-positive nuclear area relative to the total areaof cancer nuclei using a cell analysis system (CAS). Clinicopathologicalvariables including PCNA staining were assessed in relationto prognosis. Survival rate was obtained by the Kaplan-Meiermethod. The PCNA indices (percentage of the positive nucleararea) of the tumors varied from 4.4% to 96.2%. Among the clinicopathologicalvariables, only tumor size (5 cm) and depth of invasion werecorrelated significantly with PCNA index (P<0.05). Microscopically,PCNA was stained in non-keratinized cells but not in keratinizedcells. However the histological grade was not correlated withPCNA index. The survival rate was significantly worse in patientswith high PCNA indices (40%) than in those with low indices(<40%) (P<0.05). However, multivariate analysis revealedthat PCNA index was not an independent prognostic factor.     

Temporal deterioration of wavelength discrimination with successive comparison method

The wavelength discrimination threshold (Δλ) was measured with a successive comparison method, in which two stimuli of different wavelengths were presented in the left and right half of 2.2° or 2.7° bipartite field, respectively, with a certain stimulus onset asynchrony (SOA). The stimulus duration was kept constant at 110 msec. The Δλ value for five different wavelengths, 430, 470, 520, 570 and 610 nm, was found to be constant up to SOA= 60 msec and increased gradually till SOA= 190 msec. The wavelength discrimination functions with SOA of 0 and 550 msec were also obtained for 430 through 650 nm in 10 nm steps. At all wavelengths the values with SOA of 550 msec were about twice as large as those with SOA of 0 msec. The present results indicate that the wavelength discrimination deterioration is complete within a relatively short period of time.     

Roles of human CYP2A6 and 2B6 and rat CYP2C11 and 2B1 in the 10-hydroxylation of (-)-verbenone by liver microsomes.

(-)-Verbenone, a monoterpene bicyclic ketone, is a component of the essential oil from rosemary species such as Rosmarinus officinalis L., Verbena triphylla, and Eucalyptus globulus and is used for an herb tea, a spice, and a perfume. In this study, (-)-verbenone was found to be converted to 10-hydroxyverbenone by rat and human liver microsomal cytochrome p450 (p450) enzymes. The product formation was determined by high-performance liquid chromatography with UV detection at 251 nm. There was a good correlation between activities of coumarin 7-hydroxylation and (-)-verbenone 10-hydroxylation catalyzed by liver microsomes of 16 human samples, indicating that CYP2A6 is a principal enzyme in (-)-verbenone 10-hydroxylation in humans. Human recombinant CYP2A6 and CYP2B6 catalyzed (-)verbenone 10-hydroxylation at Vmax values of 15 and 21 nmol/min/nmol p450 with apparent Km values of 16 and 91 microM, respectively. In contrast, rat CYP2A1 and 2A2 did not catalyze (-)-verbenone 10-hydroxylation at all, suggesting that there were species-related differences in the catalytic properties of human and rat CYP2A enzymes in the metabolism of (-)-verbenone. In the rat, recombinant CYP2C11, CYP2B1, and CYP3A2 catalyzed (-)-verbenone 10-hydroxylation with Vmax and Km ratios (ml/min/nmol p450) of 0.73, 0.20, and 0.03, respectively. Male-specific CYP2C11 was a major enzyme in (-)-verbenone 10-hydroxylation by untreated rat livers, and CYP2B1 catalyzed this reaction in liver microsomes of phenobarbital-treated rats. Rat CYP2C12, a female-specific enzyme, did not catalyze (-)verbenone 10-hydroxylation. These results suggest that human CYP2A6 and rat CYP2C11 are the major catalysts in the metabolism of (-)-verbenone by liver microsomes and that there are species-related differences in human and rat CYP2A enzymes and sex-related differences in male and female rats in the metabolism of (-)-verbenone.     

Changes in proton magnetic resonance spectroscopy and Wechsler adult intelligence scale revised after clipping of unruptured aneurysms

The purpose of this study is to evaluate the influence of surgery for unruptured aneurysms on neuropsychological status and cerebral metabolism. We studied 21 patients with unruptured aneurysms treated with direct surgery accompanied by craniotomy, rather than by the endovascular method. Patients were evaluated before and after surgery, using the Wechsler adult intelligence scale revised (WAIS-R) and proton magnetic resonance spectroscopy which measured the ratio of N-acetyl-aspartate to creatine (NAA/Cr). Although the results of WAIS-R (total IQ, verbal IQ and performance IQ) was not significantly different after surgery in any of the patients, the total IQ of the patients with anterior communicating artery aneurysms (AcoA) showed a significant decline compared with patients with other aneurysms after surgery. Five of eight AcoA patients showed a specific reduction in verbal IQ, suggesting deterioration of recent memory. The NAA/Cr remained within the normal range and was not significantly different before and after surgery. However, the NAA/Cr in the white matter of the frontal lobe of AcoA patients showed a significant reduction compared with that of non-AcoA patients. All three elderly patients older than 70 showed a reduction in NAA/Cr of more than one standard deviation from normal subjects in their frontal or parietal lobes. These results indicated that operation for unruptured aneurysms is reliable and well established but they also show that careful consideration should be given to possible deterioration in neuropsychological status and cerebral metabolism after operation in AcoA and elderly patients.     

Prognostic impact of hypoxia-inducible factors 1alpha and 2alpha in colorectal cancer patients: correlation with tumor angiogenesis and cyclooxygenase-2 expression.

PURPOSE: Angiogenesis plays an important role in a multitude of biological processes including those of tumorigenesis and cancer progression. Hypoxia is the prime driving factor for tumor angiogenesis and the family of hypoxia-inducible factors (HIFs) plays a pivotal role in this process. The role of HIF in tumor angiogenesis has been underscored in different carcinomas but yet to be reported for colorectal carcinomas. EXPERIMENTAL DESIGN: In this study, we examined HIF [HIF-1alpha (HIF1) and HIF-2alpha (HIF2)] expression in 87 curatively resected colorectal carcinoma samples, and the results were correlated with clinicopathological factors, microvessel density, cyclooxygenase 2 expression, and patient prognosis. RESULTS: HIF1 (44.8%) was more frequently expressed than HIF2 (29.9%). Most of the clinicopathological factors representing the tumor aggressiveness were significantly correlated with overexpression of HIF2 but not with HIF1 expression. HIF2 expression had direct correlation with microvessel density and cyclooxygenase 2 expression. and, in contrast, HIF1 expression had a weak but significant inverse correlation in T1 and T2 tumors only. HIF2 expression alone and the combined expression of HIF1 and HIF2 had significant impact on patient survival. In the multivariate analysis, however, only the combined expression of HIF1 and HIF2 remained independently significant. CONCLUSIONS: Taken together, our results suggest that HIF2 expression may play an important role in angiogenesis and that the combined expression of HIF1 and HIF2 may play an important role in tumor progression and prognosis of colorectal carcinomas. Therefore, HIF expression could be a useful target for therapeutic intervention.     

Neck node metastasis after successful brachytherapy for early stage tongue carcinoma.

BACKGROUND AND PURPOSE: The accuracy of factors for predicting lymph node metastasis in patients with early-stage (stage I and II) mobile tongue carcinoma and prognostic factors associated with the clinical and pathological findings of lymph node metastasis were examined. MATERIAL AND METHODS: Between 1971 and 1998, 616 patients with early stage mobile tongue carcinoma were treated by brachytherapy with or without external irradiation. Neck lymph node metastasis occurred in a total of 237 cases, and 191 of them were not associated with primary failure. Neck dissection was performed in 169 of these 191 cases, and 16 cases were treated by radiotherapy. A pathological analysis was possible in 159 of the 169 neck dissection cases. RESULTS: There were 88 tongue cancer recurrences, and the incidence of neck metastasis was 38% (191/528) in the cases of primary controlled early tongue carcinoma, and 25% (38/151) and 41% (153/377), in stage-I and -II carcinoma, respectively. Neck metastasis was diagnosed within 12 months in 80% of cases, and within 24 months in 95%. Macroscopic appearance, tumor thickness and tumor length were identified as significant risk factors by a univariate analysis, but macroscopic appearance was the only significant risk factor identified by a multivariate analysis (P<0.001). The incidence of cervical lymph node metastasis was 62% among the invasive/ulcerative type tongue carcinomas, and was lower among the superficial type and exophytic/nodular type (20 and 35%, respectively). Regional and/or distant failure occurred in 75 of the 169 neck dissection cases (44%). The incidence of regional/distant failure was extremely high (49/68=72%) in the extra-nodal invasion group, and extra-nodal invasion was found even in small metastatic node less than 1 cm in length (20%). CONCLUSIONS: The macroscopic appearance of the primary tongue carcinoma has a major impact on the incidence of lymph node metastasis in patients with early tongue cancer, and extra-nodal invasion was the dominant risk factor for regional and distant failure. Treatment policy for clinically negative neck metastasis in early tongue cancer patients should be determined after considering the possibility of neck metastases and the morbidity associated with elective neck dissection.     

Thiamin is decomposed due to Anaphe spp. entomophagy in seasonal ataxia patients in Nigeria

A fairly high activity of a relatively heat-resistant thiaminase was detected and characterized from the pupae of an African silkworm Anaphe spp. which had been the putative cause of a seasonal ataxia and impaired consciousness in Nigerians. The thiaminase in the buffer extract of Anaphe pupae was type I (thiamin: base 2-methyl-4-aminopyrimidine methyl transferase EC 2.5.1.2), and the optimal temperature and pH were 70 degrees C and 8.0-8.5, respectively. Based on gel filtration chromatography, the molecules were estimated to be 200 kDa. Second substrates which could be utilized by the thiaminase were pyridoxine, amino acids, glutathione, taurine and 4-aminopyridine. Thiamin phosphate esters were inactive as substrates. This is the first report describing an insect thiaminase. Our results indicate the necessity of thorough heat treatment for the detoxification of the African silkworm, making the worm a safe source of high-quality protein.