Developmental Toxicity of Dimethylacetamide by Inhalation in the Rat

Developmental Toxicity of Dimethylacetamide by Inhalation inthe Rat. SOLOMON, H. M., FERENZ, R. L., KENNEDY, G. L., ANDSTAPLES, R. E. (1991). Fundam. Appl. Toxicol. 16, 414–422.Dimethylacetamide (DMAC) is a widely used industrial solvent.It has been reported to be teratogenic when given to rats byinjection or following dermal application. Most of these studiesemployed large single doses and did not examine both the fetaland the maternal response. In this study, groups of pregnantCrl:CD rats were exposed to 32, 100, or 282 ppm DMAC by inhalationfor 6 hr/day from Days 6 through 15 of gestation (day on whichcopulation plug was detected was termed Day 1G). A control groupof chambered pregnant rats was exposed simultaneously to aironly. All female rats were euthanized on Day 21G. At 282 ppm,both maternal weight gain during the exposure period and fetalweight were significantly decreased and accompanied by a significantdose-response trend. These effects were not seen in rats inhalingeither 32 or 100 ppm. Fetal resorptions were not increased inany of the groups exposed to DMAC. Fetal incidences of external,visceral, or skeletal variations and malformations were similarbetween the test and control groups. Therefore, both fetal andmaternal toxicity were noted at 282 ppm and the no-observedadverse-effect level under these experimental conditions was100 ppm for both the dam and the conceptus. DMAC was not demonstratedto produce malformations in the rat fetus even at a level thatwas toxic to the dam.     

PREDICTORS OF BEREAVED PARENTS' SATISFACTION WITH GROUP SUPPORT: AN ISRAELI PERSPECTIVE

This study evaluates various aspects of groupwork with bereaved parents who lost a child during military service. More specifically, it assesses the unique and cumulative contributions of various features of groupwork to the participants' satisfaction with the group support. One hundred and thirty-eight bereaved parents, who participated in 16 support groups, answered a battery of questionnaires tapping 3 aspects of the groupwork: their motives for joining the group, the interpersonal relations among the group members, and the group leadership style. In addition, the participants were asked to evaluate the contribution of the intervention to their adjustment. The findings indicate that the supportive elements of the intervention were associated with the groups' perceived contribution. The clinical implications of these results are discussed.     

The human α2(IV) collagen gene, COL4A2, is syntenic with the α1(IV) gene, COL4A1, on chromosome 13

We have previously assigned the gene for the α l chain of type IV collagen to chromosome 13. In this report we show that the gene coding for the second chain of this heterotrimer is on the same chromosome. This is the first example of the genes for both chains of one collagen molecule being syntenic.     

The assignment of the genes coding for human complement components C6 and C7 to chromosome 5

A panel of 19 somatic cell hybrids was tested for the presence of human sequences coding for complement components C6 and C7 by restriction enzyme digestion and Southern blots probed with human C6 and C7 cDNA probes. C7 was also detected by amplifying part of the human gene in hybrid DNA using the polymerase chain reaction. Detection of human C6 and C7 was completely correlated with the presence of chromosome 5.     

Bartter's Syndrome--Observations on the Pathophysiology

The pathophysiology of Barter's syndrome affecting seven adultshas been investigated. (1) Saralasin infusion caused a fallhi blood pressure in all patients, suggesting that angiotensinwas contributing to the maintenance of blood pressure. (2) Followinga water load, urinary chloride concentrations and osraolalitywere both low. No positive evidence for a defect in chloridereabsorption hi the ascending limb of the loop of Henle wasobtained, (3) The effect of high and low dietary sodium on plasmasodium, potassium, chloride, magnesium, renln activity, aldosterone,6-keto-PGF_ia, thromboxane B₂, urinary kalltkrein, platelet functionand erythrocyte membrane cation transport were studied. A varietyof responses was observed. Sodium restriction increased (orsodium loading decreased), plasma renin activity, aldosterone,6-keto-PGF_ia, urinary kallikrein and the platelet aggregationabnormality in some, but not all, individuals. (4) Treatmentwith indomethacin was undertaken in all patients and studiedin detail in one patient There was weight gain, increase inplasma sodium and potassium, decrease in capillary pH, positivesodium and potassium balance, and decrease in plasma renin activity,6-keto-PGF_ia, thromboxane B₂ and urinary kallikrein. Hypomagnesaemiaand excessive urinary magnesium loss persisted unchanged. (5)A variety of abnormalities of erythrocyte membrane cation transportwas found and these persisted during high- and low-sodium, andhigh-potassium Intakes; and during treatment with indomethacin,despite correction of intracellular sodium and potassium concentrations. Barter's syndrome is associated with an abnormality of erythrocytemembrane sodium and potassium transport Many of the other metabolicabnormalities may be the consequence of potassium and sodiumdepletion.