Lactate dehydrogenase activity and its isoenzymes in concentric layers of adult bovine and calf lenses.

The activity of lactate dehydrogenase (LDH) and its isoenzyme pattern were studied in four concentric layers of adult bovine and calf lenses. In both groups the specific activity of the total LDH diminished progressively toward the internal nuclear layer; the decrease was greater in the adult lenses. The enzyme activities in the cortical layers of the calf lens were lower than in the adult lens, but in the inner nuclear layers, the opposite was found. All of the 5 LDH isoenzymes were found in each layer. In both groups of animals the LDH1 isoenzyme prevailed, followed by LDH2. No differences were found in the percentage of each isoenzyme in the different lens layers. The differences in the activitie(s) of LDH found may be due to post-translational or post-synthetic modifications which may occur during the aging process.

Influence of glucocorticoid and betamimetic therapy on milk secretory IgA concentration produced by mothers delivering preterm infants.

A prospective study was performed to find the possible difference in secretory IgA concentration in milk of mothers with term pregnancy labors and those delivering at earlier gestational ages. Since tocolytic drugs and/or glucocorticoid agents are usually given in cases of threatened premature labor, the pre-term group was divided into mothers with or without medication. Thirty two mothers were distributed in three groups: Group I, mothers with preterm labors without any medication; Group II, preterm labors with previous treatment with betamimetics and glucocorticoids; Group III, term labors (see Tab. I). In each of the three groups, three periods were studied: colostral (4 to 5 days postpartum), transitional (8 to 10 days), and mature (14 to 15 days). All mothers were healthy, with good nutritional state, without local inflammation and membranes had been ruptured 12 hours or less before labor. There was no significant difference in the proportion of primiparas and multiparas in both groups. The gestational age was evaluated by amenorrhea and neonatal examination. In all mothers milk was extracted with a vacuum pump to empty the mammary gland. The determinations were made using a specific antibody against the secretory component. The concentration of free secretory component in these milks was practically insignificant. No differences were found in the concentration of secretory IgA among the three groups (Tab. II, Fig. 1) in the periods that were studied, colostral, transitional or mature. The farther away from labor that milk extraction was made, in the periods considered in our study, there is a progressive decrease in the concentration of secretory IgA (Fig. 2).(ABSTRACT TRUNCATED AT 250 WORDS)

The state of sulphydryl groups in lenses of insulin-induced hypoglycemic rats.

The level of non-protein sulphydryl compounds (NP-SH) and protein sulphydryls (P-SH) was investigated in lenses of rats with an acute and extended insulin induced hypoglycemia. No difference was found in the level of NP-SH between the controls and the rats with an acute hypoglycemia induced by cristalline insulin. After 10 hours of hypoglycemia induced by NPH insulin, the decrease of NP-SH was very significant (P less than 0.001). The level of P-SH in lenses of the animals treated with cristalline insulin was found to be lower than in the controls (P less than 0.01), the difference being more significant in the animals treated with NPH insulin (P less than 0.001). The possible reason for these findings is discussed.