Biological monitoring of occupational exposure to methyl ethyl ketone by means of urinalysis for methyl ethyl ketone itself

Summary Head space gas chromatography (GC) was applied to measure methyl ethyl ketone (MEK) in urine from 62 MEK-exposed male workers, whose individual intensity of exposure to MEK was monitored utilizing the carbon felt dosimeter. The urinary MEK level increased rapidly to reach a plateau in the first quarter of the daily 8-h work, while very little MEK was detected in the preshift urine. When the MEK levels in the urine at the end of the shift were compared with the afternoon MEK-TWA values, the uncorrected MEK in urine correlated best with MEK in air (r=0.774, n=62), while correction for creatinine gave a comparable result and the correlation was poorer when corrected for a specific gravity of urine or for the lapse of time after preceding passage of urine. Balance of MEK absorption via inhalation and MEK excretion into urine revealed that only 0.1% of MEK absorbed will be excreted unchanged into urine. Wider application of head space GC is discussed for the analysis of unmetabolized solvents in urine.     

Acute promyelocytic leukemia after living donor partial orthotopic liver transplantation in two Japanese girls

Organ transplant recipients are generally considered to be at greater risk for developing malignant disorders because of prolonged immunosuppression for organ grafting, but acute leukemia is a rare complication after organ transplantation (0.2 - 2.5%). We encountered two girls with acute promyelocytic leukemia (APL) after living donor partial orthotopic liver transplantation. In one patient, APL developed 21 months after liver transplantation for ornithine transcarbamylase deficiency. She had been administered tacrolimus for prophylaxis of graft-versus-host reaction. In the other patient, APL was diagnosed 46 months after liver transplantation for congenital biliary atresia. Both patients were successfully treated by chemotherapy including all-trans retinoic acid (ATRA), and after reaching complete remission, they have subsequently been in continuous remission. Although leukemia after liver transplantation is generally thought of as a rare complication, increases in survival rate following liver transplantation is likely to lead to more such cases, and documentation of these cases is therefore of importance.     

Non-cardiogenic pulmonary edema induced by non-ionic radiographic contrast media during the coil embolization for a ruptured cerebral aneurysm

We describe a 48(correction of 44) year-old woman, who presents a non-cardiogenic pulmonary edema caused by non-ionic radiographic contrast medium. She suffered from subarachnoid hemorrhage due to dissecting aneurysm of right vertebral artery. Cerebral angiography followed by coil embolization for the aneurysm was performed. During the interventional procedure, saturation of blood oxygen suddenly declined and chest X-ray photography obviously revealed pulmonary edema. At first we dealt with it as neurogenic phenomenon but subsequently interpreted it to non-cardiogenic pulmonary edema induced by radiographic contrast medium, since intra-arterial injection of contrast medium at follow-up angiography led the symptoms into more fulminant status. Intensive care including endotracheal intubation and continuous positive airway pressure ventilation consequently achieved complete remission and the patient discharged without any sequelae. Although low osmolar, non-ionic contrast medium has been regarded as relatively safe, severe reaction such as dyspnea, hypotension and cardiac arrest could emerge at certain intervals. We must perceive the adverse effects of it because the usage of contrast medium will dramatically increase with development of diagnostic radiographical methodology and interventional neurosurgery.     

Is the national nutrition survey in Japan representative of the entire Japanese population?

OBJECTIVE: We examined the representativeness of the sample used in the National Nutrition Survey in Japan (J-NNS). METHODS: The distribution of the J-NNS sample from 1995 to 2000 was compared with that of the national census with respect to gender, age group, place of residence, and number of household members. RESULTS: In the survey sample, as compared with the national census distributions, the proportion of females was 1% to 2% larger, the proportion of individuals who were 20 to 39 y of age was a few percentages smaller, and a slight bias toward rural areas was seen. Among individuals who were 20 to 59 y of age, the proportion of individuals who lived in single-person households was 50% to 66% of that found in the national census. Observed disparities between the sample and the population were minimal except in the case of the proportion of individuals who lived alone. CONCLUSIONS: The sample used in the J-NNS is generally representative of the entire Japanese population with the exception of individuals in single-person households.     

Triethyl tin does not induce intramyelinic vacuoles in the CNS of the quaking mouse

Intraperitoneal injection of triethyl tin (TET) sulfate, 5 or 10 mg/kg body weight did not induce intramyelinic edema without altering water content in quaking mice while in C5BL/6J and littermate control mice, water content was increased and typical intramyelinic edema was induced following TET injection. Even among control mice, however, there were some strain differences in the histological severity of the edema, which were in precise agreement with the quantitative alterations in water content. These observations suggest that CNS myelin in quaking may differ qualitatively from that in controls and the mode of response to TET is under genetic control.     

Demonstration of long-range GABAergic connections distributed throughout the mouse neocortex

Gamma-aminobutyric acid (GABA)ergic neurons in the neocortex have been mainly regarded as interneurons and thought to provide local interactions. Recently, however, glutamate decarboxylase (GAD) immunocytochemistry combined with retrograde labeling experiments revealed the existence of GABAergic projection neurons in the neocortex. We further studied the network of GABAergic projection neurons in the neocortex by using GAD67-green fluorescent protein (GFP) knock-in mice for retrograde labeling and a novel neocortical GABAergic neuron labeling method for axon tracing. Many GFP-positive neurons were retrogradely labeled after Fast Blue injection into the primary somatosensory, motor and visual cortices. These neurons were labeled not only around the injection site, but also at a long distance from the injection site. Of the retrogradely labeled GABAergic neurons remote from the injection sites, the vast majority (91%) exhibited somatostatin immunoreactivity, and were preferentially distributed in layer II, layer VI and in the white matter. In addition, most of GABAergic projection neurons were positive for neuropeptide Y (82%) and neuronal nitric oxide synthase (71%). We confirmed the long-range projections by tracing GFP-labeled GABAergic neurons with axon branches traveled rostro-caudally and medio-laterally. Axon branches could be traced up to 2 mm. Some (n = 2 of 4) were shown to cross the areal boundaries. The GABAergic projection neurons preferentially received neocortical inputs. From these results, we conclude that GABAergic projection neurons are distributed throughout the neocortex and are part of a corticocortical network.     

Development of spontaneous mouth/tongue movement and related neural activity, and their repression in fetal mice lacking glutamate decarboxylase 67

Spontaneous body movement starts at early fetal stage, at embryonic day (E) 12-15 in mice. In the present study, the movement of the head region was studied in E13-14 mice by in utero ultrasound imaging, together with the in vitro recording of underlying neural activities in the hypoglossal nerve and the ventral root of the upper cervical cord of an isolated brainstem-spinal cord preparation. The role of gamma-aminobutyric acid (GABA) in the generation of fetal movement was assessed using mice lacking GABA-synthesizing glutamate decarboxylase 67 (GAD67). At E14, mouth opening and tongue withdrawal were observed independently at frequency of 14/h each. This movement was rarely observed in the GAD67-deficient mouse. The intraventricular administration of picrotoxin or 3-mercaptopropionic acid abolished mouth opening in the wild-type mice. In a brainstem-spinal cord preparation, three types of neural discharge were recorded: mouth/tongue-moving burst, respiratory burst and irregular activity on the basis of their waveform, regularity in occurrence and concomitant muscle activity. In the GAD67-deficient mice, the occurrence of mouth/tongue-moving burst and irregular activity was inhibited to about 15 and 40% of those in the wild-type mice, respectively. Respiratory burst was slightly inhibited but the difference was not significant. Picrotoxin greatly reduced the frequency of mouth/tongue-moving burst. These results indicate that GABA is involved in rhythm generation in movement of the head region and support the hypothesis that cleft palate in the GAD67-deficient mouse is due to the impairment of mouth or tongue movement that assists palate formation.     

Frontotemporal dementia with co-occurrence of astrocytic plaques and tufted astrocytes, and severe degeneration of the cerebral white matter: a variant of corticobasal degeneration?

We report two patients who exhibited frontotemporal dementia (FTD) with unusual neuropathological features. The ages of the patients at death were 65 and 67 years, the disease durations were 6 and 5 years, and the clinical diagnoses were Picks disease and corticobasal degeneration (CBD), respectively. At autopsy, both cases exhibited neuropathological findings compatible with those of CBD, including atrophy of the frontal and parietal lobes, neuronal loss and gliosis in the cortical and subcortical regions, and presence of cortical ballooned neurons and astrocytic plaques (APs). In both cases, immunoblotting of insoluble tau exhibited the pattern of selective accumulation of four-repeat tau, a finding that is also compatible with CBD. However, severe degeneration was evident in the frontal and parietal white matter in both cases. Moreover, a striking finding was the widespread presence in the affected cortex of tufted astrocytes (TAs), which are characteristic of progressive supranuclear palsy (PSP). Neither co-occurrence of APs and TAs nor severe degeneration of the cerebral white matter is a feature of either CBD or PSP. No mutations were found in the tau gene in either case. In conclusion, the possibility that these two cases represent a new neuropathological phenotype of non-familial FTD rather than simply a variant of CBD cannot be completely excluded.