Antimicrobial Resistance in Salmonella enterica Serovar Typhi Isolates from Bangladesh,Indonesia, Taiwan,and Vietnam

We characterized Salmonella enterica serovar Typhi isolates from Bangladesh, Indonesia, Taiwan, and Vietnam to investigate their genetic relatedness and antimicrobial resistance. The isolates from Bangladesh and Vietnam were genetically closely related but were distant from those from Indonesia and Taiwan. All but a few isolates from Indonesia and Taiwan were susceptible to all antimicrobials tested. The majority of isolates from Bangladesh and Vietnam were multidrug resistant (MDR) and belonged to the widespread haplotype H58 clone. IncHI1 plasmids were detected in all MDR S. Typhi isolates from Vietnam but in only 15% of MDR isolates from Bangladesh. Resistance genes in the majority of MDR S. Typhi isolates from Bangladesh should reside in the chromosome. Among the isolates from Bangladesh, 82% and 40% were resistant to various concentrations of nalidixic acid and ciprofloxacin, respectively. Several resistance mechanisms, including alterations in gyrase A, the presence of QnrS, and enhanced efflux pumps, were involved in the reduced susceptibility and resistance to fluoroquinolones. Intensive surveillance is necessary to monitor the spread of chromosome-mediated MDR and fluoroquinolone-resistant S. Typhi emerging in Bangladesh.     

In vivo gastric mucosal histopathology using endocytoscopy

AIM:To study the ability of endocytoscopy to identify normal gastric mucosa and to exclude Helicobacter pylori(H.pylori) infection.METHODS:Endocytoscopic examination of the gastric corpus and antrum was performed in 70 consecutive patients.Target biopsy specimens were also obtained from the assessed region and multiple H.pylori tests were performed.The normal endocytoscopy patterns of the corpus and antrum were divided into the normal pit-dominant type(n-Pit) or the normal papilladominant type(n-Pap), respectively characterized as either regular pits with capillary networks or round, smooth papillary structures with spiral capillaries.On the other hand, normal mucosa was defined as mucosa not demonstrating histological abnormalities, including inflammation and atrophy.RESULTS:The sensitivity and specificity of n-Pit for normal mucosa in the gastric corpus were 94.4%and 97.1%,respectively,whereas those of n-Pap for normal mucosa in the antrum were 92.0%and 86.7%,respectively.The positive predictive values of n-Pit and n-Pap for H.pylori-negative tissue were 88.6%and 93.1%,respectively,and their negative predictive values for H.pylori-negative tissues were 42.9%and41.5%,respectively.The inter-observer agreement for determining n-Pit and n-Pap for normal mucosa were0.857 and 0.769,respectively,which is considered reliable.CONCLUSION:N-Pit and n-Pap,seen using EC,are considered useful predictors of normal mucosa and theabsence of H.pylori infection.     

Effect of 1,1,1-Trichloroethane Inhalation on Heart Rate and Its Mechanism: A Role of Autonomic Nervous System

The response of heart rate to acute 1,1,1-trichloroethane (1,1,1-TCE) inhalation and its mechanism via the autonomic nervous system were studied in anesthetized dogs in acute inhalation experiments. Concentrations of 1,1,1-TCE in inspired air of 1.32 ± 0.14% (mean ± S.E.) increased heart rate, but 2.79 ± 0.24% decreased heart rate. Opposite reactions of heart rate were observed when blood pressure decreased to 70–80 mm Hg following inhalation. Moreover, both tachycardia from relatively low concentrations and bradycardia from higher concentrations were blocked by pre-administration of adrenergic beta blocker, but were only slightly affected by vagotomy. It is suggested that both tachycardia and bradycardia following 1,1,1-TCE inhalation may be controlled by the sympathetic nervous system.     

Atypical Osteosarcomas in Werner Syndrome (Adult Progeria)

Werner syndrome (WS), adult progeria, is more common in Japan than elsewhere. It predisposes to osteosarcoma (OS) and five other rare tumors. To determine if and how OS is atypical in this genetic disorder, we studied the characteristics of ten Japanese cases with respect to clinical features, pathology, and radiographs, and compared them with a hospital series of 36 skeletal OS with the same atypical age-range, 35–57 years. The anatomic sites were also atypical: seven ankle/foot, two radius and one patella compared with only one at the ankle in the hospital series. The osteoblastic cell-type was about equally frequent in both series, but, among others than the three major subtypes, there was only one in WS as compared with 14 (39%) in the hospital series. The types of mutations were sought in five WS cases with OS. One showed no mutation at any of the ten known loci for Japanese, two were of type 4/4 and two of type 6/6. The mutations 4 and 6 have been found in 66% of alleles of WS cases in Japan. The increased frequency and unusual age and site distributions of OS in WS may be due to increased susceptibility, related to later-life leg ulcers, and weight-bearing on spindly ankles weakened by severe loss of lower limb subcutaneous tissue.     

Reproductive toxicity of ethylene glycol monoethyl ether in Aldh2 knockout mice

Ethylene glycol monoethyl ether (EGEE) can cause damage to testes and sperm, and its metabolites are believed to play an important role in its toxicity. Aldehyde dehydrogenase 2 (ALDH2) is involved in the metabolism of this chemical. To investigate whether and how the enzyme affects the toxicity of EGEE, we conducted experiments comparing Aldh2 knockout mice with wild-type mice. Administration of EGEE at 100 and 600 mg/kg/day for one week did not induce any significant change in the weight and body weight ratios of testes, prostate and epididymides in either Aldh2 knockout or wild-type mice. However, motion of sperm from the spermaduct, as analyzed with a Hamilton-Thorne Sperm analyzer, was slightly decreased in the low dose group, and significantly lower in the high dose group; and the percentage of progressive sperm was also reduced in the two EGEE groups. This effect of EGEE treatment was observed in the wild-type, but not in the Aldh2 knockout mice. Sperm motion from the cauda epididymides was not affected. On the other hand, the concentration of ethoxyacetic acid, a metabolite of EGEE, in 24 h pooled urine of EGEE-treated Aldh2 knockout mice was not significantly lower than that of the wild-type mice on most days of urine sampling. These results suggest that inactivation of the ALDH2 enzyme due to gene mutation may be linked to differences in the susceptibility to EGEE-induced sperm toxicity.     

Ultrastructural characterization of enterochromaffin-type cells in human gastric carcinoma

Ultrastructural characterization has been performed on eosinophilic granular cells occurring in gastric carcinomas. Of these, the present paper dealt with enterochromaffin (EC)-type cells. EC-type cells were identified by the presence of eosinophilic granules, immunoreactivity for serotonin (5 HT) and argentaffinity. Conventional electron microscopy revealed that they bore membrane bound, electron-dense granules of varying size (100-800 nm in shorter diameter), which were larger than those of normal EC cells. Their shapes are round, rod-shaped and concave. The granules are immunolabeled for 5HT by both pre- and post-embedding methods. The preembedding method also disclosed diffuse cytosolic immunoreactivity. Both differentiated-type and undifferentiated-type gastric carcinomas showed essentially the same results. General trends of occurrence of Paneth-like and EC-type cells in gastric carcinomas were also discussed. The present study confirmed that EC-type cells in gastric carcinoma retained basic characteristics of EC cells despite of morphological deviation from the normal cells. It is speculated that they are derived from neoplastic precursor cells with a special differentiation.