[Effects of ultraviolet laser beam irradiation on rabbit cornea and lens]

Rabbit eyes were irradiated by an ultraviolet laser beam in with to investigate its effects on the corneal endothelium, thickness of the cornea, and lens. An Excimer laser beam (gas; XeCl) with wave length of 308 nm and with energy intensity of 0.02, 0.07, 0.2, 0.6, 1.7, 3.0, 4.0, or 5.1 J/cm2 was irradiated to the right eye using 3 rabbits for each energy intensity (24 rabbits in all) in order to examine changes occurring in the right eye compared with the left eye from immediately after irradiation to 32 days thereafter. The results obtained were as follows: 1. Corneal thickness UV laser beam irradiation at 0.02, 0.07, and 0.6 J/cm2 caused immediate thickening of the cornea (p less than 0.01). The cornea thickness returned to normal 14 days later. Irradiation at 3.0 and 4.0 J/cm2 resulted in remarkable thickening, which returned to normal 28 days after irradiation. By irradiation at 5.1 J/cm2, the corneal thickness increased markedly (0.333 +/- 0.019 mm in control eyes and 0.405 +/- 0.05 mm in irradiated eyes) immediately after irradiation. It tended to gradually return to normal and was reduced to the pre-irradiation thickness on the 32nd day after irradiation. 2. Corneal endothelial area and morphology (the number of angles) The area of the corneal endothelium increased after irradiation. However, no significant differences were noted at any energy intensity, because of the larger scattering of the values in the control eyes. The ratio of hexagonal cells tended to decrease even by energy intensities above 0.7 J/cm2. However, no significant differences were found at any energy intensity level.(ABSTRACT TRUNCATED AT 250 WORDS)

An experimental study on the respiratory toxicity of isopropyl alcohol

Guinea-pigs were exposed to 400 ppm or 5500 ppm of isopropyl alcohol (IPA) for 24 successive hours, and they were killed immediately after the exposure period. The ciliary activities of the nose and trachea were examined. In addition, the epithelium of the nose and trachea was observed by scanning and transmission electron microscopy. The present study showed that exposure to 400 or 5500 ppm of IPA vapor caused deterioration of the ciliary activity and also some pathological changes. Although our study revealed that exposure to 400 ppm of IPA vapor can affect the mucosa of the nose and trachea, the ciliary activity of the 400-ppm exposure group was not too poor and morphological changes were rather mild. Recovery from such degeneration might be rapid. Therefore, our study supports the justification of the allowable IPA level recommended by ACGIH.

Pupillary changes due to work using visual display terminals

In order to measure the degree of ocular fatigue and general fatigue among the workers using visual display terminal (VDT), pupillary dynamics were measured with open-loop light stimulation for 26 subjects of a mean age of 25.9 years. VDT loads were TV games for 30 min under indirect light of 100 lux. The eight parameters of pupillary light reflex with open-loop pupillometer were examined before and after VDT loads. On the right eyes, two parameters and one value increased 9.2% (Student's t-test: P less than 0.005, max.), 25.7% (Student's t-test: P less than 0.005, Min.) and 14.8% (Student's t-test: P less than 0.005, min/max) just after the load and then gradually decreased and returned to the pre-load level after a 10 to 15-min rest period. Two parameters increased 11.7% (Student's t-test: P less than 0.05, 1/2C) and 12.9% (Student's t-test: P less than 0.05, VD), one parameter decreased -9.0% (Student's t-test: P less than 0.05, 0.63D) and three parameters were constant (Student's t-test: L, A and VC) just after the load. On the left eyes, the same tendencies were observed. But there were no significant differences (Student's t-test) between the right and left eyes. The change pattern of the eight parameters were small in degree and similar to the changes when the sympathetic nervous system was activated.

Recovery process of tracheal mucosa of guinea pigs exposed to isopropyl alcohol

The toxicity of isopropyl alcohol (IPA) on the tracheal mucosa was studied experimentally with special reference to the recovery process of the organ. The results showed that 400 ppm IPA has an acute effect on the mucociliary system in the tracheal mucosa, and that recovery from such degeneration can occur in 2 weeks. When functional and morphological damage was induced by a higher level (5500 ppm) of IPA, recovery did not occur in 2 weeks. The conclusion is that the present allowable level of IPA is reasonable from the viewpoint of the effects of short-term exposure to IPA on the tracheal mucosa. In addition, a higher level of IPA exposure has longer-term effects on the tracheal mucosa, and workers exposed to such a higher level of IPA vapor should be given careful otolaryngological follow-up observations.

Structure and expression of human thrombomodulin, a thrombin receptor on endothelium acting as a cofactor for protein C activation

We have deduced the entire 575-amino acid sequence of the human thrombomodulin precursor from cDNA clones. The precursor starts with an 18-residue signal peptide domain, followed by the NH2-terminal domain, a domain with six epidermal growth factor-like structures, an O-glycosylation site-rich domain, a 24-residue transmembrane domain and a cytoplasmic domain. Simian COS cells transfected with the expression vector pSV2 containing thrombomodulin cDNA synthesized immunoreactive and functionally active thrombomodulin.

Zinc content in Japanese food and estimated average daily intake

The zinc content of 284 types of 1, 693 food items commonly eaten by the Japanese was measured and a zinc content table was prepared based on the Food Standard Composition Table (4th edition). A good correlation was found between the values calculated using this table and the zinc content of 15 cooked meals. This table provides an estimate of the zinc intake in the average diet of Japanese people. Urban adult inhabitants were asked about the foods they had eaten using the 24-hour recall method and the average daily zinc intake was calculated to be 10.8 mg for males and 9.5 mg for females.

Acute effects of isopropyl alcohol exposure on the middle ear mucosa

Guinea pigs were exposed to 400 ppm or 5500 ppm of isopropyl alcohol (IPA) for 24 successive hours, and then middle ear mucosal samples in both proximal and distal sites to the eustachian tube were obtained for functional and morphological examinations. The ciliary activity was examined according to the photoelectric method of Ohashi and Nakai. The morphology of the middle ear lining was examined by transmission electron microscopy. The results showed that IPA at the allowable level of 400 ppm has an acute effect on the mucociliary system of the middle ear mucosa. Recovery from damage occurs within two weeks. At higher levels of exposure to IPA (more than 10 times the allowable level) moderate deterioration of the ciliary activity and severe damage of epithelial cells were observed and recovery within two weeks was not seen. It is concluded that IPA at the allowable level of 400 ppm does not cause significant middle ear disorders, but workers exposed to higher levels of IPA should be given careful otolaryngological examinations and follow-up observations.

The Velotrace: a device for monitoring velar position

This paper describes the Velotrace, a mechanical device designed to allow the collection of analog data on velar position. The device consists of two levers connected through a push rod and carried on a pair of thin supports rods. The device is positioned in the nasal passage with the internal lever resting on the nasal surface of the velum and the external lever positioned outside the nose. The movements of the external lever reflect the movement of the internal lever as it follows velar movement and are recorded as an analog signal using an optoelectronic position-sensing system. Results of evaluation studies indicate that the Velotrace accurately reflects the relatively rapid movements of the velum during speech.

Degeneration and regeneration of respiratory mucosa of rats after exposure to styrene

The recovery process of pathological changes in the respiratory mucosa following exposure to styrene were experimentally studied to improve the understanding of the respiratory toxicity of styrene. Thirty male SD rats were exposed to 150 ppm or 1000 ppm of styrene for 4 h a day over 3 weeks (5 days a week). They were killed for examination at 1 day or 12 weeks after completion of the exposure sequence. Bilateral mucosal samples from the nasal septum and the trachea of the animals were examined for ciliary activity and subjected to electron microscopy. Complete functional and morphological recovery of the nasal and tracheal mucosa was observed at the 12th week post-exposure to 150 ppm of styrene. After exposure to 1000 ppm of styrene, almost normal function and morphology of the tracheal mucosa was found at the 12th week post-exposure, but the nasal mucosa continued to show decreased ciliary activity and an affected morphology.

[Clinical evaluation of imipenem/cilastatin sodium in children]

Nine pediatric patients with moderate or severe bacterial infections (3 septicemia or bacteremia, 2 pyelitis, 2 tonsillitis, 1 pneumonia and 1 pyothorax) in hospital were treated with MK-0787/MK-0791. The drug was administered intravenously by 30 or 60 minutes drip infusion in 3 or 4 divided doses totalling 24 mg/24 mg-70.2 mg/70.2 mg per kg/day. Clinical effectiveness were excellent in 4 cases, good in 2 cases, poor in 2 cases and not evaluated in 1 case. The overall efficacy rate was 75%. A slight decrease of WBC was observed in 1 case. It was concluded that MK-0787/MK-0791 was a useful antibiotic for the treatment of infections in pediatric practices. Pharmacokinetics of intravenously administered MK-0787/MK-0791 was studied in 2 other cases. The MK-0787/MK-0791 was administered intravenously by 30 or 60 minutes drip infusion to 2 cases at a dose of 10 mg/10 mg/kg. The mean half-life (T1/2) of MK-0787 was 1.03 hours and MK-0791, 0.69 hour. The mean urinary recovery rate of MK-0787 within 6.5-7 hours after administration was 62.5% and MK-0791, 76.7%.

Alterations in nociception after intracisternal administration of prostaglandin D2, E2 or F2 alpha to conscious mice

The effect of intracisternal administration of three major prostaglandins on nociceptive responses was evaluated in mice. Prostaglandin D2 had biphasic effects on pain thresholds (hot plate and acetic acid writhing tests) when given in a dosage range of 5 ng to 5 micrograms per mouse. Lower doses of prostaglandin D2 (less than or equal to 15 ng) increased the sensitivity to pain stimulation. Higher doses (greater than or equal to 50 ng) caused hypoalgesia, which was completely blocked by intracisternal injection of 500 pg of naloxone. Prostaglandin E2 (5 ng-5 micrograms) also had a biphasic effect on pain thresholds, similar to the effect of prostaglandin D2. However, the hypoalgesia caused by a higher dose of prostaglandin E2 (5 micrograms) was not blocked at all by naloxone doses of up to 500 ng. Prostaglandin F2 alpha had little effect on pain thresholds. These results indicate that each prostaglandin has a specific effect on the modulation of nociception.

[Clinical study of BRL 25000 (clavulanic acid-amoxicillin) granules in pediatric infections]

BRL 25000 granules, a formulation of amoxicillin (AMPC) and the beta-lactamase inhibitor clavulanic acid (CVA) in a ratio of 2 to 1, was studied clinically and bacteriologically in pediatric infections. The in vitro antibacterial activity of BRL 25000 was superior to AMPC against beta-lactamase producing strains. The pharmacokinetics of the BRL 25000 granule were studied following oral administration to a 6 years old female and 9 years old male in the fasting state at dose levels of 10 mg/kg and 16.1 mg/kg, respectively. In the case of the female dosed at 10 mg/kg, the peak serum concentrations were found to be 6.38 micrograms/ml for AMPC and 1.83 micrograms/ml for CVA at 1 hour following administration. The elimination half-life of AMPC was 0.86 hour and that of CVA was 0.67 hour. The 4-hour urinary recovery was 61.89% for AMPC and 17.92% for CVA. In the male receiving 16.1 mg/kg, the peak concentrations were 2.55 micrograms/ml for AMPC at 3 hours following administration and 1.46 micrograms/ml for CVA at 1.5 hours following administration. The elimination half-life of AMPC was 1.59 hours and that of CVA was 1.19 hours. The 6-hour urinary recovery was 44.19% for AMPC and 30.05% for CVA. In clinical studies, the BRL 25000 granule was administered to 36 infants with upper respiratory tract infections, mainly tonsillitis, urinary tract infections etc. Good clinical efficacy was obtained in 33/36 cases (91.7%). Diarrhea and rash were occasionally noted side effects but were not severe. From the above results, it can be concluded that the BRL 25000 granule is a suitable and effective drug for use in the treatment of pediatric infections.

Morphological change in the corneal endothelium due to ultraviolet radiation in welders

To clarify the relationship between morphological changes in the corneal endothelium and ultraviolet (UV) radiation, specular microscopic examinations were performed on both eyes of 118 welders and 85 controls. The results showed: a decrease in the hexagonal cells in welders (20-29 years) in comparison with the controls (20-29) (p less than 0.05); an increase in the mean cell size of the endothelium and a decrease in the hexagonal cell population with increasing age in both groups; increases in standard deviation (SD) and the coefficient of variation (CV) of the mean cell size in both groups; increases in SD and CV of the mean number of cell cell sides in both groups; and no difference in the mean cell size between the two groups. These results show that UV radiation damages not only the corneal epithelium but also the endothelium, and suggest that it causes more pleomorphic change (a decrease in hexagonal cell population) than enlargement of the mean cell size.