Minimal effect of brain temperature changes on glutamate release in rat following severe global brain ischemia: a dialysis electrode study

Using a dialysis electrode, we recently developed an oxygen-independent system for real-time measurement of the glutamate concentration in the extracellular space ([Glu]e) during ischemia. This system allows separate evaluation of intra-ischemic biphase [Glu]e elevation, i.e. release from synaptic vesicles (1st phase), reversed uptake of glutamate from metabolic pools in neuronal cells (2nd phase), and post-ischemic glutamate re-uptake in ischemia-reperfusion models. Using the system, we attempted to clarify the relationship between biphase glutamate release and brain temperature in a model of acute global ischemia produced by transecting both carotid arteries. Our results showed that, in contrast to mild hyperthermia, hypothermia did not inhibit the 1st phase of [Glu]e release, and changes in intra-ischemic brain temperature had a minimal effect on the 2nd phase of [Glu]e elevation during severe acute ischemia. These findings, together with our previous data, indicate that brain temperature change in the intra-ischemic period plays an important role in disturbance of the glutamate re-uptake system during ischemia.     

Osteoclastogenesis inhibitory factor exhibits hypocalcemic effects in normal mice and in hypercalcemic nude mice carrying tumors associated with humoral hypercalcemia of malignancy

In the present study, we attempted to determine the extent to which an anterior capsulorrhexis carried out during cataract surgery contracts postoperatively. The size of the continuous curvilinear capsulorrhexis (CCC) was measured at the end of surgery and at the final follow-up examination in 52 eyes of 40 patients who underwent phacoemulsification/aspiration and implantation of an intraocular lens (IOL) with 6-mm optics. Images obtained by video during surgery and by slit-lamp microscopy were used to determine the CCC size with reference to the optics of the IOL. The average CCC size was 5.0 mm at the end of surgery; it contracted to 4.4 mm by the final postoperative examination. The contraction of the anterior capsule progressed rapidly in the first 50 days following surgery and then gradually thereafter. The extent of contraction was greater in older patients. The smaller the CCC size immediately after surgery, the more rapidly it contracted. The size of the capsulorrhexis contracted an average of 22% following cataract surgery. The contraction rate tended to be higher in older patients. The results suggest that the capsulorrhexis carried out in cataract surgery for elderly patients should be sufficiently large, but not larger than the optics size of the IOL.     

Psychosocial evaluation on the correct recollection of periodic medical checkups of workers. 2. Long-term change in the recalled results of medical checkups

A self-administered questionnaire study of 333 workers (male 253, female 80) in a manufacturing company was carried out one month after informing the workers of the results of their medical checkups in 1993. The questionnaire included several items such as recalled abnormal findings of health examination and ways of overcoming the abnormal findings, recalled results of their medical checkups in 1992, self-confidence in their recollection of the results, and the usefulness of medical checkups. The following were investigated: the relationship between actual as well as recalled results of medical checkups in 1992 and the recollection of them after one year, the effects of examinations after medical checkups in 1992 on their recollection of the checkup results after one year, the effects of actual as well as recalled 1992 checkup results on the recollection of the results one month after informing the workers of the results of their medical checkups in 1993, assurance of correct recollection of the results, the relationship between the usefulness of medical checkups, explanation of abnormal findings and the percentage of correct answers to the results of medical checkups in 1993 one month after informing the workers of their results. It was found that the percentage of correct answers to the results after one year was significantly lower than that after one month in 1992. The rate decreased with the increase in the number of abnormal items in medical checkups. Moreover, the rate also decreased when the results were abnormal. Further examinations in addition to the medical checkups influenced their recollection somewhat after one year. The results that the workers still remembered in 1992 had a stronger effect on their recalling the results one month after informing them in 1993 than the actual results in 1992. The workers' confidence in their recollection of the results was untrustworthy in the same way as their recollection of the results, and they were not able to maintain the recollection of the correct results, although many of the workers realized the usefulness of the medical checkups. Our results suggest that explanation of abnormal medical findings in 1993 was effective because the percentage of partial concordance between actual and recalled results was much higher in the workers who received the explanation than in the workers who did not receive it.     

Hypertrophic cranial pachymeningitis with spinal epidural granulomatous lesion

A 67-year-old woman with a one-year history of tinnitus and headache had multiple cranial nerve palsies of V, VII, VIII, IX, X, XI and spastic paraparesis. She also had a secretory otitis media. Gd-DTPA-enhanced magnetic resonance imaging (MRI) revealed hypertrophy of the dura of the posterior fossa and spinal epidural mass which extended from C7 to T10. A biopsy of the epidural mass showed chronic granulomatous change. These lesions were completely cured with administration of antibiotics. We believe this case of double-lesion of hypertrophic cranial pachymeningitis and spinal epidural granulomatous lesion originated from a bacterial infection secondary to the secretory otitis media.     

Phase and magnetic properties of iron oxide clusters in 20CaO·20SiO2·7Fe2O3·6FeO glasses

The annealing of 20CaO·20SiO₂·7Fe₂O₃·6FeO glasses at 973K in vacuo produced clusters of iron oxide, the shape of which was nearly spherical and the diameter distributed in the narrow range 25–115Å. The phase of clusters was identified to be Fe³⁺(Fe³⁺ _{poststagger|1.30}Fe²⁺ _{poststagger|0.55}V_0.15)·O₄ in the inverse spinel structure based upon the Mössbauer spectra and x-ray diffraction profiles. The clusters exhibited superparamagnetism and their effective anisotropy energy constant was inversely proportional to the cluster diameter. The magnetization of the glasses measured by a vibrating sample magnetometer was 7.2 × 10^-6 Wbmkg^-1 at 10 kOe at room temperature and smaller than the value calculated assuming that the whole clusters have superparamagnetism. These results suggest the pinning of spins near the cluster surface.     

Ribotyping and a study of transmission of Staphylococcus aureus collected from food preparation facilities

Food poisoning from Staphylococcus aureus is sometimes caused by improper handling of food items in food preparation facilities. Prevention of contamination by employees is particularly important in facilities where a significant amount of food preparation is performed by hand. Some experiments have been performed to describe bacterial cross-contamination in the food preparation process, but there have been few studies of cross-contamination in actual food preparation facilities. Aiming to shed light on the transmission of S. aureus in food preparation facilities, this study collected samples of 66 strains of this bacterium from the fingers of food preparation staff, foodstuffs, prepared foods, cooking utensils, and cooking equipment and typed them with the ribotyping method. S. aureus from the same ribogroup was detected on the hands of a study participant, a faucet, knife, frying pan, and a salad, indicating that bacteria found on the hands of the study participant was transmitted to cooking utensils and prepared foods. Transmission (from a faucet to a frying pan handle) of bacteria by another person, a third party, was also detected.     

Cloning and heterologous expression of a beta-fructofuranosidase gene from Arthrobacter globiformis IFO 3062, and site-directed mutagenesis of the essential aspartic acid and glutamic acid of the active site

We have cloned the gene encoding a beta-fructofuranosidase from Arthrobacter globiformis IFO 3062, and subsequently, the gene was heterologously expressed in Escherichia coli. This beta-fructofuranosidase gene encodes a protein of 548 amino acid residues with a calculated molecular mass of 60,519 Da. We have examined the roles of three residues of A. globiformis IFO 3062 beta-fructofuranosidase by site-directed mutagenesis, and found that aspartic acid 130 and glutamic acid 392, which are two of the apparent catalytic residues, are essential for hydrolase activity. This study provides the first experimental evidence showing that these two amino acid residues of beta-fructofuranosidase play a critical role in hydrolyzing sucrose.     

Apatite formation on collagen fibrils in the presence of polyacrylic acid

Recently, we reported the formation of bone-like apatite on collagen fibrils by biomimetic method. Compounds containing carboxyl moieties are believed to be effective in the formation of apatite. Polyacrylic acid [-CH2CH(COOH)-]n (PAAc) is widely used in dentistry. In the present study, the effect of PAAc in the formation of apatite from revised simulated body fluid (R-SBF) on collagen fibrils was studied. Two different experimental approaches were tried to study the effect of PAAc present in the collagen and in the R-SBF solution. In the first, collagen gel was soaked with 1 mg/ml PAAc (molecular weights 25000 and 100000) for the time intervals of 30 min and 6 h. The gels were then dried in air and incubated in R-SBF. Characterization of the precipitates formed on the collagen fibrils in gel showed that the formation of apatite was inhibited when soaked in PAAc for 6 h. In the second experiment, when PAAc (0.1 and 1.0 mg/ml) was mixed with R-SBF the microstructure of the precipitates formed on collagen fibrils was affected partially. Hence, it is confirmed that the presence of PAAc in the biomimetic environment of collagen affects the mineralization of apatite.