Increase in signal intensities on T1-weighted magnetic resonance images in asymptomatic manganese-exposed workers

OBJECTIVES: To clarify the clinical significance of increased signal intensities on T1 weighted magnetic resonance imaging (MRI) we performed a large-scale epidemiological study on asymptomatic manganese (Mn)-exposed workers with its focus on MRI. METHODS: We randomly selected 121 male workers out of a total of 750 workers including Mn-exposed, non-exposed manual, and non-exposed clerical workers in the factories. We studied environmental and biological monitoring, neurological examination, and MRI. RESULTS: The proportion of workers with increased signal intensities among the exposed, the non-exposed manual workers, and the non-exposed clerical workers was 46.1%, 18.8%, and 0%, respectively. Especially, 73.5% of the welders showed increased signal intensities. In no subject, were clinical signs of manganism observed. The pallidal index correlated with blood Mn concentration. CONCLUSION: Increase in signal intensities on the T1-weighted image reflect recent exposure to Mn, but not necessarily manganism. At which increase of signal intensity, the progression of manganism from Mn exposure occurs, remains to be solved.     

Alfentanil co-induction for laryngeal mask insertion

We assessed the effect of two different doses of alfentanil (5 and 10 micrograms.kg-1) on the conditions for laryngeal mask airway insertion in ASA 1 and 2 patients who received propofol for induction of anaesthesia. One hundred and fifty unpremedicated patients were randomly allocated to receive either propofol 2.5 mg.kg-1 only (Group P), alfentanil 5 micrograms.kg-1 and propofol 2.5 mg.kg-1 (Group A5), or alfentanil 10 micrograms.kg-1 and propofol 2.5 mg.kg-1 (Group A10). The addition of alfentanil to propofol resulted in a greater ease of insertion and a better quality of airway patency. Pretreatment with alfentanil also resulted in a significantly higher success rate during the first attempt at inserting the laryngeal mask airway compared with Group P (Group P 58%, Group A5 96%, Group A10 94%). Patients in Group P were apnoeic for a mean (+/- SD) time of 3.3(+/- 1.9) min, 4.71 (+/- 2.2) min in Group A5, and 7.32(+/- 4.3) min in Group A10. The use of alfentanil 10 micrograms.kg-1 with propofol, however, led to a significant decrease in mean arterial pressure and heart rate. We concluded that pretreatment with intravenous alfentanil 5 micrograms.kg-1 prior to propofol provides excellent conditions for insertion of laryngeal mask with minimal adverse haemodynamic changes.     

Surfactant protein A and stable microbubble formation in tracheal aspirates

This study aimed to determine the role of surfactant protein A (SP-A) in the formation of stable microbubble in tracheal aspirates. Our results showed that as the concentration of anti SP-A antibodies added to tracheal aspirate specimens increased, the number of stable microbubble formed in the specimen decreased. The correlation between stable microbubble counts and the SP-A levels in the tracheal aspirates was good, r = 0.85, p < 0.05. This study suggests that SP-A plays an important role in stable microbubble formation. Measurement of small stable microbubbles is thus a useful bedside test for predicting the SP-A activity in the tracheal aspirates and in indirect measurement of lung maturity.     

Attenuation of voluntary ethanol consumption by dopamine-beta-hydroxylase inhibition (FLA-57): mediated by changes in aversion, reinforcement or both

The dopamine-beta-hydroxylase inhibitor, FLA-57, was reported by several investigators to reduce voluntary ethanol consumption in rats. The nature of the effect of FLA-57 on this behavior had been attributed to its involvement in both the mediation of positive reinforcing and aversive processes. In the present study, the capacity of FLA-57 to induce a conditioned taste aversion (CTA) in both a forward and a "nominally backward conditioning" paradigms was investigated. This was done in an attempt to assess the possible contribution of a FLA-57-induced CTA to the previously observed reduction in ethanol intake in several drinking studies. Furthermore, the ability of FLA-57 to induce a CTA in a nonnovel situation, where the taste of the presented solution (ethanol or saccharin) was familiar to the animals, was also assessed. The inclusion of these specific conditions was necessitated by the attempt to create conditions similar to those prevalent in drinking studies. We found that FLA-57, in both conditioning paradigms, induced a significant CTA. Animals, naive and experienced with the taste of ethanol or saccharin, exhibited a CTA following the administration of FLA-57. However, the magnitude and rate of extinction of the observed CTAs did not resemble those observed in studies on the effects of FLA-57 on ethanol intake. The results of this study suggest that while it is possible that FLA-57 exerts its effect on ethanol intake, at least in part, through an aversive mechanism, such a mechanism is unlikely to be the exclusive process through which ethanol ingestion is attenuated.     

Validity and cost-effectiveness of diagnostic procedures in CS2 poisoning

To determine relatively useful diagnostic procedures of carbon disulfide (CS2) poisoning in terms of validity and cost-effectiveness, several diagnostic tests are evaluated on 1,552 people by prevalence ratio (exposed/nonexposed), dose-response relationship, sensitivity and specificity, and the cost of the tests. Several symptoms with high kappa indices are found to be useful in various combinations, showing a consistent dose-response relationship and high exposed-nonexposed ratio. In clinicopathologic tests on functions of the kidney, liver and hematopoietic systems, eight items out of 22 have been shown to have significant dose-response relationship, mostly in liver function tests. A thorough dental examination failed to identify any useful indicator peculiar to the CS2 poisoning. Unlike Western people, the prevalence of coronary heart disease among Koreans was too low to be useful in the diagnosis of CS2 poisoning. Among four elective tests, i.e., Minnesota Multiphasic Personality Inventory (MMPI), Brain magnetic resonance imaging (MRI), nerve conduction velocity (NCV), and fluorescent angiography (FAG), the NCV appeared to be a more sensitive and specific test than the others are. Combinations of the tests improved the probability of diagnosing CS2 poisoning cases when any one test out of four was positive. Addition of other valid tests increased the probability of excluding non-cases. It was concluded that diagnosis of CS2 poisoning could be made validly and inexpensively if the diagnostic tests were carefully chosen step by step.     

Transient hyperthyroidism following L-asparaginase therapy for acute lymphoblastic leukemia

The effect of L-asparaginase on the thyroid gland has not been well documented. We report the first two cases of hyperthyroidism associated with thyroid nodule following L-asparaginase therapy for acute lymphoblastic leukemia (ALL). The thyroid function abnormalities were not severe, short-lived and did not require specific therapy.     

The yield for colorectal cancer and adenoma by indication at colonoscopy

Colonoscopy is an integral part of the clinician armamentarium in the diagnosis of colorectal cancer and its precursor, the adenoma. Polypoid lesions when identified can be excised at colonoscopy and in turn reduce the risk of colorectal cancer. We prospectively evaluated the yield of colorectal cancer and adenomatous polyps by indication for colonoscopy over a one-year period. A total of 375 colonoscopies were carried out. The more common indications of colonoscopy were rectal bleeding, abdominal pain, surveillance of colorectal cancer and altered bowel habit. The highest yield for cancer was for rectal bleeding with 12.5% while surveillance of patients with a history of polyps yielded the highest percentage of new polyps. We conclude that rectal bleeding as an indication for colonoscopy yielded the highest number of cancers.