Chlorination for degrading saxitoxins (paralytic shellfish poisons) in water.

Chlorination was investigated as a treatment option for degrading and thus removing saxitoxins (paralytic shellfish poisons, PSPs) produced by cyanobacteria (blue-green algae) from water. It was found to be effective with the order of ease of degradation of the saxitoxins being GTX5 (B1) approximately dcSTX > STX > GTX3 approximately C2 > C1 > GTX2. However the effectiveness of chlorine was pH dependent. Degradation as a function of pH was not linear with the degree of degradation increasing rapidly at around pH 7.5. At pH 9 > 90% removal was possible provided a residual of 0.5 mg l(-1) free chlorine was present after 30 min contact time. The more effective degradation at higher pH was unexpected as chlorine is known to be a weaker oxidant under these conditions. The more effective degradation, then, must be due to the toxins, which are ionisable molecules, being present in a form at higher pH which is more susceptible to oxidation. The feasibility of using chlorine to remove saxitoxins during water treatment will therefore depend strongly on the pH of the water being chlorinated. Degradation may be improved by pH adjustment but may not be a practical solution. Although saxitoxins were degraded in that the parent compounds were not detected by chemical analysis, there is no indication as to the nature of the degradation products. However, acute toxicity as determined by the mouse bioassay was eliminated.

Local application of methotrexate for ectopic pregnancy with a percutaneous puncturing technique.

Management of ectopic pregnancy remains traditionally surgical. Early detection of unruptured ectopic pregnancies, using both ultrasound techniques and beta-human chorionic gonadotropin (beta-hCG) assays, allows a more conservative treatment. Twenty-six tubal pregnancies, which were managed with local methotrexate (MTX) injection, are presented. A single dose of 10-12.5 mg of MTX was percutaneously injected into the gestational sac under abdominal sonographic control. Complete resolution was obtained in all our patients. Four of them required a second percutaneous administration 4 days after the first one. Negligible serum beta-hCG levels (< 10 mIU/ml) were reached within 42 days after treatment. No systemic side effects were observed. Local administration of MTX under abdominal sonographic control seems to be an effective alternative for the treatment of ectopic pregnancy. The main potential advantages of the method are (1) a greater antitrophoblastic effect; (2) a shorter treatment period; (3) reduced dosage, and (4) absence of side effects.

Ocular surface and environmental changes.

PURPOSE: To investigate if ocular surface and precorneal tear film are influenced by the environment. METHOD: We studied the environmental influences on the ocular surface using the tests Break-up time, Schirmer-1 test and Rose Bengal staining. We correlated the values of the above tests among three groups of normal people from different places in Greece with different climates and levels of atmospheric pollution. Group A consisted of 57 persons coming from an area with a dry and warm climate and heavy atmospheric pollution. Group B consisted of 55 normal persons coming from an area with a dry and warm climate and a low level of atmospheric pollution. Group C consisted of 55 persons coming from an area with a humid and cool climate and a low level of atmospheric pollution. RESULTS: Schirmer-1 test and Break-up time are influenced by the climatic conditions but they are not influenced by the atmospheric pollution, while Rose Bengal staining is not influenced either by the climate or by the atmospheric pollution. CONCLUSION: The precorneal tear film is much more influenced by the climatic conditions than by the atmospheric pollution.

High nitrate content in drinking water: cytogenetic effects in exposed children.

The potential genotoxicity of nitrates and nitrites-contaminants of drinking water that have been implicated in carcinogenesis-was investigated in this study. Sister chromatid exchanges and frequency of chromatid/chromosome aberrations were studied in peripheral blood lymphocytes of 70 children who were 12-15 y of age. These children were permanent residents in geographical areas of Greece, where elevated concentrations of nitrates (i.e., 55.70-87.98 mg/l) existed in drinking water. The control group comprised 20 healthy children who resided in areas with very low nitrate concentrations (i.e., 0.7 mg/l). A significant increase in the mean number of chromatid/chromosome breaks was observed in children exposed to nitrate concentrations that exceeded 70.5 mg/l (p < .01), but there was no significant increase in the mean number of sister chromatid exchanges per cell. The results indicate that chronic administration of elevated concentrations of nitrate in drinking water has the capability of inducing cytogenetic effects.

Oocyte donation to women over 40 years of age: pregnancy complications.

Recently, oocyte donation to women of advanced age has led to a considerable number of conceptions, thus increasing the age limit for becoming pregnant. A main consideration encountered by physicians, though, is the potential medical and obstetric complications of a pregnancy at an advanced age. In this study, the obstetric complications, as well as the perinatal outcome, of pregnancies of aged recipients (above 40) are presented and compared to those of younger recipients. A significantly higher incidence of gestational diabetes (P < 0.001), an increased incidence of pre-eclampsia (at the 10% level of significance) and an increased risk for thrombophlebitis (again at the 10% level) was observed in the older patients, but a careful follow-up during their pregnancy led to a highly satisfactory obstetric and perinatal outcome. A rigorous precycle medical screening (especially for cardiovascular diseases and diabetes) and a careful follow-up during pregnancy is, therefore, imperative so that oocyte donation to older women is not withheld and continues to provide fertility possibilities to otherwise sterile patients.

Myomectomy during pregnancy and caesarean section.

Myomectomy was performed on a 31 year old primigravida during the 15th week of pregnancy due to a large myoma which was 23 cm in diameter. At the 39th week of pregnancy, during the Caesarean section, eight fibroids obstructing the lower part of the uterus were removed. There were no maternal or fetal complications.

Experience with isoxsuprine in the treatment of sickle cell crisis: a proposed mechanism of action.

An accidental clinical observation triggered this investigation into the possible beneficial effects of isoxsuprine in the treatment of painful sickle cell crisis. Twenty-four patients were studied with a total of 34 episodes of painful crisis. As they had all been previously treated by us we knew the duration of their crisis under conventional treatment, so that the two regimens with and without isoxsuprine could be compared. Isoxsuprine was administered in 3 successive steps: (1) as an IM injection (5-10 mg), (2) as a rapid IV infusion (1 mg/minute), and (3) as a slow, continuous IV infusion, (0.1-0.3 mg/minute). The results from this study suggest that isoxsuprine exerts in fact a remarkable action in sickle cell crisis by bringing about prompt relief in approximately 80% of the cases within 5 hours, and in 40% of the cases within 2 hours. There were only 2 cases of absolute failure. The hospitalization time was remarkably reduced and the use of narcotics was minimized. Side effects (tachycardia, palpitations, somnolence) have been observed mainly in cases where relatively high doses of isoxsuprine had to be administered IV.

Some operations research applications to problems of health care systems (a survey).

In this paper, a brief survey of operations research applications to problems of health care systems is made. It shows the possibilities which exist for improving the design and operations of hospitals and other health care systems through the use of operations research approaches. The different applications have been divided into groups, but it should be noted that there is a great deal of overlapping among them.