Measurement of residual 152Eu activity induced by atomic bomb neutrons in Nagasaki and the contribution of environmental neutrons to this activity

Residual 152Eu activities induced by neutrons from the Nagasaki atomic bomb were measured for nine mineral samples located up to 1,061 m in the slant range and one control sample at 2,850 m from the hypocenter. A chemical separation to prepare europium-enriched samples was performed for all samples, and gamma ray measurements were carried out with a low background well-type germanium detector. In this paper, the measured specific activities of 152Eu are compared with activation calculations based on the DS86 neutron fluence and the 93Rev one. The calculated-to-measured ratios are also compared with those of 60Co and 36Cl. The present results indicate that the measurements agree to the calculation within a factor of three as observed in the nuclear tests at Nevada. The activation level of environmental neutrons and the detection limit for 152Eu are also discussed.     

Significant dose effect of carbamazepine on reduction of steady-state plasma concentration of haloperidol in schizophrenic patients

A reduction in haloperidol concentration induced by carbamazepine coadministration has been consistently reported. However, the degree of this reduction is very different among individuals treated with various doses of carbamazepine. Thus, we investigated dose effect of carbamazepine on the steady-state plasma concentration of haloperidol. Eleven excited schizophrenic inpatients, despite receiving haloperidol 12 mg/d, were treated with incremental doses of carbamazepine for 6 weeks (100, 300, 600 mg/d for 2 weeks each). Plasma drug concentrations were monitored together with clinical assessments before and after each phase of the 3 carbamazepine doses. Mean haloperidol concentrations during coadministration of carbamazepine 100, 300, and 600 mg/d were 75%, 39%, and 15%, respectively, of corresponding variables before carbamazepine coadministration. Negative linear correlations were observed between dose or plasma concentration of carbamazepine and the degree of reduction in haloperidol concentration. Mean carbamazepine dose and plasma carbamazepine concentrations at 50% reduction of haloperidol concentration were 240 mg/d and 3.5 microg/mL, respectively. Scores in total and excitement symptoms were significantly reduced after carbamazepine coadministration, whereas no changes were observed in other clinical symptoms or any of the subgroup side effects. Therefore, this study indicates that carbamazepine decreases plasma haloperidol concentration in a dose-dependent or concentration-dependent manner, and that reduction in haloperidol concentration is apparent even at subtherapeutic dose of carbamazepine.     

Midazolam can potentiate the analgesic effects of intrathecal bupivacaine on thermal- or inflammatory-induced pain

Epidurally administered midazolam can potentiate analgesia by epidural bupivacaine. However, whether this effect is synergistic or additive is not known. In this study, we investigated the spinally-mediated analgesic interaction between midazolam and bupivacaine by using the tail-flick and formalin tests in rats with chronically implanted catheters. Behavioral effects were also observed. The dose dependency of analgesia and the 50% effective doses of intrathecal midazolam and bupivacaine were determined, and then the interaction of these two drugs was examined with an isobolographic analysis. Both drugs had dose-dependent analgesic effects in both the tail-flick test and the formalin test. The 50% effective dose values of the combination were significantly lower than the calculated additive values in both tests (P = 0.023 in the tail-flick test; P = 0.0025 in Phase 1 and 0.047 in Phase 2 of the formalin test). Behavioral side effects decreased in the combination group compared with each drug alone. In conclusion, intrathecally administered midazolam and bupivacaine had synergistic analgesic effects on acute thermal- or inflammatory-induced pain, with decreased behavioral side effects. IMPLICATIONS: In both acute thermal- and inflammatory-induced pain, intrathecally administered midazolam and bupivacaine produced synergistic analgesia with decreased side effects in intrathecally catheterized rats.     

Detection of acute tolerance to the analgesic and nonanalgesic effects of remifentanil infusion in a rabbit model

Although acute tolerance to analgesia develops rapidly with remifentanil, it is unknown whether acute tolerance also develops to its nonanalgesic effects. We investigated the analgesic and cardiorespiratory effects of remifentanil during a continuous infusion in a rabbit model. Ten tracheotomized New Zealand White rabbits with arterial and venous accesses were placed on a sling that allowed for reasonably free movement. In spontaneously breathing conscious animals, remifentanil was infused IV at a constant-rate of 0.3 microg kg(-1)x min(-1) for 360 min. Sedative/analgesic and cardiorespiratory variables were assessed repeatedly during remifentanil infusion, including the number of animals behaviorally unresponsive to clamping the forepaw (nonresponders) and subcutaneous electrical stimulation thresholds required to elicit head lift (HLT: pain detection/arousal threshold) and escape movement responses (EMT: pain tolerance threshold). Within 60-120 min of starting the infusion, the number of nonresponders, HLT, EMT, and PaCO(2) increased significantly, whereas blood pressure, heart rate, and respiratory rate decreased. Thereafter, all variables returned towards preinfusion levels despite continuing infusion. These results indicate that during a remifentanil infusion acute tolerance develops for both its analgesic and cardiorespiratory effects. IMPLICATIONS: Using a new rabbit model, we found that during continuous, constant-rate remifentanil infusion acute tolerance developed within the first few hours, not only to its analgesic but also to its cardiovascular and respiratory effects, albeit in slightly different time courses.     

Comparison of barium swallow,CT and thallium-201 SPECT in evaluating responses of patients with esophageal squamous cell carcinoma to preoperative chemoradiotherapy

The aims of this study were to compare the results of thallium-201 (Tl-201) SPECT, barium swallow and CT in the assessment of the effect of preoperative chemoradiotherapy. This study consisted of 28 patients with advanced esophageal squamous cell carcinoma (AESCC) who underwent the three imaging modalities before and after preoperative chemoradiotherapy. The results were quantified using the bidimensional method for barium swallow and contrast-enhanced CT and the tumor-to-lung ratio for SPECT. The percent decrease in these quantitative values after therapy was defined as %Dba, %Dct and %Dtl respectively. The histological effect of the chemoradiotherapy was determined from the resected surgical specimen of the esophagus: grade 0, 100% viable tumor cells; grade 1a, 99-67%; grade 1b, 66-34%; grade 2, 33-1%; grade 3, no viable cells. A statistically significant difference of %Dtl between the subgroups of each grade was evident (p = 0.0433), whereas no significant differences were evident for %Dba (p = 0.1778) or %Dct (p = 0.7377). However, the overlap of %Dtl between these groups was marked. Although thallium-201 SPECT cannot be used to evaluate the therapeutic effect with acceptable accuracy, SPECT may be of additional value to barium swallow and CT in assessing the response of AESCC to preoperative chemoradiotherapy.     

The usefulness of<Superscript>99m</Superscript>Tc-hexamethylpropyleneamineoxime white blood cell scintigraphy in a patient with eosinophilic gastroenteritis

White blood cell (WBC) 99mTc-hexamethylpropyleneamineoxime (HMPAO) scintigraphy was performed in a patient with eosinophilic gastroenteritis. WBC accumulation was detected in the terminal ileum to descending colon, and pathological studies demonstrated eosinophilic infiltration at the same region. 99mTc-HMPAO-WBC scintigraphy was proved to be a useful tool for the detection of eosinophilic infiltration in eosinophilic gastroenteritis.     

Detection of Oxalobacter formigenes in human feces and study of related genes in a new oxalate-degrading bacterium

The first objective of the present study was to examine the presence of Oxalobacter formigenes (an oxalate-degrading bacterium in the human intestine) according to sex in a large number of Japanese. The second objective was to study the presence of three related genes in Bifidobacterium breve, which is considered to be a new oxalate-degrading bacterim. Fecal samples were collected from 55 male and 37 female healthy volunteers. O. formigenes was detected by a polymerase chain reaction (PCR) and a culture-based method. DNA was amplified by the PCR method including the site of important base sequences of each gene in order to detect oxc, frc, and OxlT. O. formigenes was present in 80% of 54 male and 62% of 34 female subjects in the PCR-based assay, while it was present in 62% of 40 male and 50% of 24 female subjects in the culture-based assay. The partial base sequences of the three related genes in B. breve were determined. The RNA polymerase-binding site in promoters and the rho-independent termination sequence were preserved in oxc and frc. In conclusion, the rate of the presence of O. formigenes was the same as in previous reports. Female subjects showed a 15% lower rate than males. B. breve is considered to be an oxalate-degrading bacterium since it was found to have oxalic acid-degrading ability and three genes involved in oxalate degradation.     

Two cases of 46,XX male with chief complaint of infertility

We report two cases of XX male with chief complaints of infertility. Physical examination of both patients aged 42 and 29 demonstrated normal male habitus except for small testes. Semen analyses demonstrated no spermatozoa. Endocrinological examinations showed hypergonadotrophic hypogonadism. Vesiculograms demonstrated normal seminal tracts. Histological examination of their testes did not reveal germ cells; one case lacked seminiferous tubules and there was hyalinization in the seminiferous tubule in another case. Chromosomal analyses of peripheral blood demonstrated 46,XX. The sex-determining region Y gene was positive and DAZ (deleted in azoospermia) gene was negative in both cases.