Ionic strength influences hemolytic action of dibucaine hydrochloride

BACKGROUND: Little is known about effect of ionic strength on local anesthetic toxicity. Using human erythrocytes, hemolytic action of dibucaine in solutions of various ionic strength was investigated. METHODS: The critical micellar concentration (CMC) of dibucaine and the dibucaine level that causes destruction of half of the red blood cells in vitro (EC50 value) were determined in solutions of various ionic strength. RESULTS: The mean CMC values of the dibucaine solutions adjusted to ionic strength 0.15, 0.30, 0.45 and 0.90 with NaCl, were 35.3, 22.6, 15.9 and 9.6 mM, respectively. The mean EC50 values of these solutions measured at 5 sec were 22.5, 16.0, 12.6 and 8.2 mM, respectively, and those at 30 min were 4.9, 4.5, 4.5 and 2.6 mM, respectively. There was a significant correlation between mean CMC values and mean EC50 values at 5 sec but not at 30 min in the solution of the same ionic strength. CONCLUSIONS: These findings indicated that the mechanism of dibucaine-induced hemolysis within a few seconds is through membrane lysis, whereas dibucaine-induced hemolysis at 30 min is caused by another mechanism. Because each mechanism is enhanced by high ionic strength, dibucaine dissolved in salt solution should not be administered intrathecally.     

Uptake of cadmium in meals from the digestive tract of young non-smoking Japanese female volunteers

OBJECTIVES: To estimate rates of cadmium (Cd) uptake from the digestive tract and changes in Cd in biological specimens after intake of Cd mainly in rice. METHODS: Twenty-five young non-smoking Japanese female volunteers (20-23 in age) were recruited and a 20-d experimental study was conducted. With polished rice containing 0.004 ppm and 0.340 ppm of Cd, Meal L and Meal H were prepared. Approximately 12% of total Cd in Meal L and 92% of total Cd in Meal H originated in rice. The volunteers ate Meal L for 11 d to achieve a stable intake-output balance of Cd. Fifteen of the 25 volunteers ate Meal H on the 12(th) day (Group D1), and the remaining 10 ate Meal H on the 12(th), 13(th) and 14(th) day (Group D3). All 25 subjects then resumed the consumption of Meal L to the end of the study (20(th) day). All meals, feces and urine were collected during the study, and Cd intake from the daily meals (Cd-I), Cd in feces (Cd-F) and Cd in urine (Cd-U) were determined. For measurement of Cd in blood (Cd-B), venous blood was collected from all volunteers on the day before the study and again on the 12(th) and 20(th) day; venous blood was also collected from 4-8 volunteers at additional time points. RESULTS: Mean Cd-I was 4.51 microg/d (range: 1.85-6.93) or 48.48 microg/d (range: 27.98-56.27) when they ate Meal L or Meal H. Cd-F and Cd-B exhibited faster responses to the change in Cd-I than did Cd-U. The Cd(uptake) rate, defined as (1-Cd-F(excess) /Cd-I(excess)) (Fig. 1), was 47.2% (range: -9.4-83.3%) in Group D1 and 36.6% (range: -9.2-73.5%) in Group D3, and the Cd(balance) rate, defined as (1-Cd-F(output) /Cd-I(intake)), was 23.9% (range: -4.0-37.7%) in Group D1 and 23.7% (range: -8.2-56.9%) in Group D3. CONCLUSIONS: Cd-F and Cd-B are better biological monitoring parameters for assessing change in Cd-I than Cd-U. The Cd(uptake) and Cd(balance) rates appeared to be higher than those in previous papers when ingested Cd mainly originated in rice.     

Cortical blindness following aortic arch surgery

PURPOSE: To report a patient with Marfan's syndrome in whom cortical blindness occurred after planned circulatory arrest during aortic arch surgery. CASE: A 31-year-old man underwent aortic arch surgery because of an acute aortic dissection due to Marfan's syndrome. He noticed poor vision after surgery, although his pupillary reflexes and fundi appeared normal. Magnetic resonance imaging (MRI) and positron emission tomography (PET) were performed 2 years and 9 months after his operation. RESULTS: The MRI revealed cortical atrophy in the occipital cortex, and PET scans with fluorodeoxy glucose revealed extreme glucose hypometabolism in the occipital cortex. The atrophy reflected cortical laminar necrosis that presumably occurred during the planned circulatory arrest to the brain during the surgery. CONCLUSION: It is occasionally difficult to diagnose cortical blindness with MRI, especially at the acute stage. We could find significant hypometabolism of the occipital cortex using PET.     

Cerebellar activation during ataxic gait in olivopontocerebellar atrophy: a PET study

OBJECTIVE: To investigate the possible abnormal regional brain metabolism during ataxic gait in olivopontocerebellar atrophy (OPCA), and to evaluate the response of the cerebellar subregions to instability during bipedal gait. MATERIAL AND METHODS: On 9 patients with OPCA in early phase and on 10 age-matched normal subjects, we performed positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) under two different conditions: supine resting and 30 min treadmill walking. RESULTS: Both in normals and in patients with OPCA, the FDG uptake in the walking state (Uwalk) was significantly greater than that in the resting state (Urest) in the pyramis, declive-folium-tuber and culmen of the cerebellar vermis, and in the thalamus. In the patients, the Uwalk was also significantly greater than the Urest in the posterior lobe of cerebellar hemisphere and in the pons and midbrain. In the pyramis, the activation ratio (= Uwalk/Urest) of the patients was significantly lower than that of the normals. CONCLUSIONS: We considered that these findings reflect the pathophysiology of ataxic gait in OPCA patients and the compensatory mechanism for the instability during ataxic gait.     

Carpal tunnel syndrome grading system in rheumatoid arthritis

The grading system of Hashizume and Hirooka for carpal tunnel syndrome (CTS) was modified to refine the system for surgical treatment selection for specific subsets of CTS in patients with rheumatoid arthritis (RA). The grading system uses clinical signs and symptoms of CTS, including pain indications, to identify surgical subsets of patients to facilitate treatment selection. Retrospective analysis of the system included radiographic and electromyographic findings. Twenty-nine hands of 21 adult patients with CTS in RA were graded in the current study. Eight hands with mild synovitis received conservative treatment only. Endoscopic carpal tunnel release (ECTR), using Okutsu's universal subcutaneous endoscopic system with a clear cannula, was performed in 11 hands with moderate synovitis. Open carpal tunnel release (OCTR) combined with flexor tenosynovectomy was performed in 9 hands with severe synovitis. One more hand required OCTR after ECTR when malignant RA was diagnosed. Clinical results, evaluated using Kelly's criteria, were: excellent in 19 hands, good in 5, fair in 4, and poor in the 1 patient with malignant RA. Clinical symptoms of CTS improved in all but the latter patient. Although the sample size in the current study is small, the results appear to warrant further study to determine the clinical utility of the grading system. Received: April 2, 2001 / Accepted: November 1, 2001     

Impact of digital dermoscopy analysis on the decision to follow up or to excise a pigmented skin lesion: a multicentre study

Background: The quality of early malignant melanoma (MM) diagnosis is dependent on the experience of dermatologists, tools like dermoscopy and histopathology, and awareness and education of the studied population. Does a higher rate of excision of pigmented skin lesions (PSL) increase the rate of detected melanomas? Material and Methods: The DB‐MIPS objective tool, able to evaluate mathematical defined variables, has been used to verify the variability of measurements among PSL stored by five different centres located in Italy, Switzerland, and Germany. Results: The objective analysis showed low differences in terms of moles' features among the different groups, arguing for robustness of the dermatological patient's PSL inspection. Differences in terms of false positives and predictive positive values have been detected. The tendency to follow up a lesion was proportional to the percentage of thin MM (<0.75 mm tumour thickness), while the interventism was proportional to the percentage of dysplastic moles. Similar percentage of thin melanoma has been observed in all the centres, indicating a standardization in early diagnosing among experienced dermatologists. The main difference among the centres was their mode of action, i.e. to follow up or remove suspicious PSL. Conclusion: Interventism depends neither on the geographic site nor on the features of the observed moles. Higher removal rates do not correspond to higher MM detections: this means that an in‐depth knowledge of melanoma patterns is required and follow‐up of suspicious moles is highly suggested.     

Expression and localization of the LGN protein in the mouse brain with reference to its relationship with Gαi2

It has been suggested that the LGN protein is associated with Gα_i2 by the yeast two-hybrid system and in vitro pull-down assay. To determine the functions of LGN in the central nervous system, we examined the expression and localization of LGN in mouse brain by immunoblotting and immunofluorescence microscopy. By immunoblotting, almost similar amounts of LGN were detected in the olfactory bulb, cerebral cortex, hippocampus, and cerebellum of the adult mouse brain, and the levels of the postnatal LGN expression in the whole brain were fairly constant. Immunofluorescence microscopy showed that LGN is localized in nuclei of the neurons in the olfactory bulb, cerebral cortex, and hippocampus, but in both nuclei and cytoplasm of Purkinje cells in the cerebellum. On the other hand, Gα_i2 was distributed throughout the neuronal elements except for the nuclei. Thus, LGN and Gα_i2 were colocalized in the cytoplasm of Purkinje cells, but not in other neurons examined. These results suggest that LGN may be involved not only in the Gα_i2-mediated signaling but also in other signaling pathways.