Increased formaldehyde in jet engine exhaust with changes to JP-8, lower temperature, and lower humidity irritates eyes and respiratory tract.

BACKGROUND: Formaldehyde (FA) in exhaust from F-4 aircraft with low smoke combustor(LSC) J79 engines has been reported to be of sufficient concentration to cause irritation. It has also been noted that eye and respiratory irritation became more frequent and severe after the fuel was changed from JP-4 to JP-8. The present sturdy investigated the effect of jet fuel and power setting on formaldehyde concentrations in the exhaust. We also investigated the exposure to formaldehyde among pilots and flight line personnel. METHODS: The exhaust from LSC J79 engines using different types of fuel (JP-8 and JP-4) was sampled 50 m behind the engine at different power settings in July (summer season in Japan) and February (winter season ). It was also sampled at 75% power settings using JP-8 in July. RESULTS: At an idle power setting, the FA concentration was higher in the exhaust of engines using JP-8 (1.31 ppm in July and 2.78 ppm in February) than in engines using JP-4 (0.95 ppm in July and 1.84 ppm in February). The FA concentration increased as both ambient temperature and relative humility decreased in the sampling atmosphere. The FA concentration of JP-8 fuel at an idle power setting (65%) was higher than that at a 71.5% power setting (1.32 ppm and 0.86 ppm, respectively). CONCLUSIONS: The FA concentrations in LSCJ79 engine exhaust varies depending on the type of fuel, engine power settings, and ambient air conditions. A high FA concentration at ground level due to a change in the fuel type, low temperature, and humidity, causes frequent severe eye respiratory irritation.

A 25-year prospective study of visual acuity in the Japan Air Self Defense Force personnel.

BACKGROUND: In the Japan Air Self Defense Force (JASDF), new vision standards for student pilots allow lower uncorrected monocular acuity (from 1.0 to 0.8). In flight environments, where the use of corrective lenses may present problems, the risk of decreasing visual acuity in pilots who should wear corrective lenses must be defined. METHODS: We conducted a 25-yr prospective study of visual acuity with regard to distance vision in 752 JASDF nonaviation personnel followed from ages 20 to 45. The test subjects were divided into four groups according to their right monocular visual acuity at entry: > or =1.0, between 0.9 and 0.7, between 0.6 and 0.2, and <0.2. RESULTS: At entry, 94.1% of all subjects had visual acuity > or =0.7. The proportion of subjects who required corrective lenses for distance increased with age from 15.8% to 37.1%. After 25-yr, 30.2% of subjects with visual acuity > or =1.0 at entry and 62.7% of subjects with visual acuity between 0.9 and 0.7 at entry required corrective lenses. CONCLUSIONS: Over 25 yr, the population with the best eyesight at age 20 had a lower increase in the need for corrective lenses than the population with visual acuity between 0.9 and 0.7 at age 20. These results suggest an increased risk of visual acuity loss in pilots over time as a result of the lower vision standards for student pilots in the JASDF.

Evaluation of nano-optical probe from scanning near-field optical microscope images.

We studied a nanometre-sized optical probe in a scanning near-field optical microscope. The probe profile is determined by using a knife-edge method and a modulated transfer function evaluation method which uses nanometre-sized line-and-space tungsten patterns (with spaces 1 microm to 50 nm apart) on SiO2 substrates. The aluminium-covered, pipette-pulled fibre probe used here has two optical probes: one with a large diameter (350 nm) and the other with a small diameter (10 nm). The small-diameter probe has an optical intensity approximately 63 times larger than that of the large-diameter probe, but the power is about 1/25 of that of the large probe.

Adrenergic neurotransmitters and calcium ionophore-induced situs inversus viscerum in Xenopus laevis embryos.

Xenopus laevis embryos at the blastula-early tail bud stage were exposed to norepinephrine or octopamine dissolved in culture saline until they reached the larval stage. The left-right asymmetry of the heart and gut was then examined. We found that these adrenergic neurotransmitters induced situs inversus in the heart and/or gut in up to 35% of tested neurula embryos. Norepinephrine-induced situs inversus was blocked by the alpha-1 adrenergic antagonist prazosin. Furthermore, A23187, a calcium ionophore, also increased the incidence of situs inversus up to 54% when late-neurula embryos were exposed to the solution. A23187 treatment initiated before neural groove formation was less effective. The incidence of situs inversus induced by these reagents decreased towards the control level (2.2%, 25 untreated embryos out of 1127 embryos in total) in embryos past the stage of neural tube closure. In the present experiments we obtained 22 gut-only situs inversus embryos having an inverted gut and a normal heart. In contrast, such embryos were not observed among the 1127 untreated embryos. An adrenergic signal mediated by an increase in intracellular free calcium may be involved in the asymmetrical visceral morphogenesis of Xenopus embryos.

+Gz acceleration affects the trace minerals zinc, copper, and chromium in serum and urine of humans.

BACKGROUND: Research investigating the relationship between physical training and trace mineral concentrations has primarily focused on athletes. Few investigations, however, have specifically examined the alterations of trace mineral concentrations occurring in humans exposed to +Gz acceleration. Exercise alters mineral content; G-exposure is a form of exercise; therefore, G-exposure may elicit changes in mineral content. HYPOTHESIS: Exposure to +Gz acceleration may affect the concentrations of the trace minerals zinc, copper, and chromium in human serum and urine. METHODS: Blood samples were obtained from 7 men and 3 women, before and immediately after +Gz acceleration. Urine samples were obtained before, 30 min after, and 2 h after +Gz acceleration. RESULTS: The serum zinc concentration was significantly different after +Gz acceleration, decreasing from 90.6 +/- 21.0 micrograms.dl-1 to 80.8 +/- 14.4 micrograms.dl-1. The serum copper concentration was also significantly altered immediately after +Gz acceleration, decreasing from 111.7 +/- 27.5 micrograms.dl-1 to 98.5 +/- 35.2 micrograms.dl-1. The urinary zinc and copper concentrations, and the serum chromium concentration were not significantly affected by +Gz acceleration. CONCLUSIONS: The circulating levels of these minerals presumably change as they are transported to the tissues requiring greater amounts due to the increased physiological work associated with +Gz acceleration.

G-related musculoskeletal spine symptoms in Japan Air Self Defense Force F-15 pilots.

The introduction of the F-15 Eagle to the Japan Air Self Defense Force (JASDF) in the early 1980's seemed to increase musculoskeletal problems of the spinal column among pilots. The neck is the body part most vulnerable to high-G force injuries, and serious cases of neck injury have been reported. We surveyed 129 F-15 pilots from different air bases by means of a questionnaire. The occurrence rate of musculoskeletal problems in different types of aircraft was analyzed according to the pilots' flying experience. Of the surveyed pilots, 115 (89.1%) reported muscle pains related to flying. Of those who experienced pain, each averaged 7.6 events, 95% of which occurred in the F-15. Of these 115, 30% experienced pain in the F-4 and 15% in the F-1. The "checking six" position was the most common posture at the time of injury, followed by "forward bend." Of the 115 pilots, 44 stated that their symptoms adversely affected flight duty performance, and 50 pilots stated that their symptoms adversely affected daily life. The effectiveness of muscle training as a preventive measure was supported by 62%. Some oriental therapeutic methods (acupuncture, moxa cautery, and finger-pressure massage) were preferred by pilots for pain treatment. G-related problems of the spinal column still exist as a major medical concern in JASDF.

Comparison of efficacy, toxicity and pharmacokinetics of free adriamycin and adriamycin linked to oxidized dextran in rats.

Adriamycin linked to oxidized dextran (ADM-OXD) via Schiff's base formation was compared with free adriamycin with regard to antitumor activity, acute toxicity and plasma pharmacokinetics in rats following i.v. administration. ADM-OXD showed higher activity against Walker carcinosarcoma 256 than free adriamycin. On the other hand, the acute toxicity of ADM-OXD was about three times less than that of free adriamycin. In contrast to free adriamycin, a very high plasma level of adriamycin was found after i.v. administration of ADM-OXD. The area under the plasma concentration curve with ADM-OXD was about 160-fold higher than with free adriamycin. Thus, the improvement of the therapeutic index in the case of ADM-OXD might be due to the difference in the disposition of ADM-OXD and free adriamycin in rats.

[The evaluation of ultrasonic oocyte collection techniques for IVF-ET--comparing the transabdominal and transvaginal methods].

In order to evaluate the effectiveness and safety of ultrasonic oocyte collection for IVF-ET, a comparative study was performed on the results of IVF-ET by the transabdominal and transvaginal methods in 145 cycles of 51 patients. The oocyte collection rate for the transvaginal method was significantly higher than that for the transabdominal method (77.1% vs. 68.7% per follicle, p less than 0.01). The majority of the oocytes were collected in three follicular flushings. The fertilization rate for oocytes collected by the transabdominal method was significantly higher than that for those collected by the transvaginal method in cases of tubal damage and endometriosis (81.1% vs. 65.6% per oocyte, p less than 0.01). There was no significant difference between the signs of complications seen with the two methods. Six successful pregnancies were obtained by IVF-ET in our hospital (4 cases by the transabdominal method, and 2 cases by the transvaginal method). Two of these cases have already delivered full term healthy male infants. In conclusion, these results indicate that ultrasonic oocyte collection has been established as the most effective method for IVF-ET by means of either the transabdominal or the transvaginal methods.

Attempts to suppress experimental allergic encephalomyelitis in rats with alpha fetoprotein.

Rats of the Lewis strain were immunized with bovine basic myelin protein to develop experimental allergic encephalomyelitis. Neither human nor rat fetal sources of purified alpha-fetoprotein were able to significantly ameliorate the development of this dyscrasia. The plasma of pregnant rats at term was without effect. Immunization of pregnant rats was also accompanied by the usual course of development of typical encephalomyelitis.