Studies on (pro)insulin biosynthesis and secretion of pancreatic islets of sand rats (Psammomys obesus) after different feeding conditions

It was possible to induce different metabolic states in sand rats of our breeding colony or in newly caught Egyptian sand rats, respectively, by feeding a pellet diet or vegetable diet (green cabbage). Newly captured sand rats fed only on native food were used as reference group (group C). Plasma IRI-level and glucose in vivo and [3H]-leucine incorporation into proinsulin and insulin, insulin secretion and insulin content in vitro were investigated. Sand rats fed on pellet chow and ad libitum (group B) developed a hyperinsulinism and showed higher sensitivity of [3H]-leucine incorporation into proinsulin and insulin to glucose (maximal stimulation at 3 mM) and increased incorporation rates in vitro. Restriction of pellet food to 35-40 kcal/animal/day (group A) lead to changes of all parameters, which were investigated in the same direction as in group B, but to a much smaller extent. Newly captured sand rats, which were fed green cabbage for 4 to 6 weeks divided into two groups: One group (group D1) was comparable to the normal group (C) in IRI levels, glucose levels, glucose sensitivity and amount of [3H]-leucine incorporation. The other group (group D2) tended to group A. Marked changes in insulin content and insulin secretion of isolated pancreatic islets could not be found in any group.

Different responses of active and inactive plasma renin to various stimuli

1. The response of active and inactive plasma renin to orthostasis and frusemide and to inhibition of prostaglandin synthesis by indomethacin was tested in normal human volunteers. 2. Active renin increased by orthostasis and frusemide and decreased by indomethacin. The latter also blunted the increase of active renin after stimuli. 3. Inactive renin was slightly increased by orthostasis, but was not significantly influenced by acute administration of frusemide or inhibition of prostaglandin synthesis by indomethacin. 4. The results show differences in the response of active and inactive renin to stimuli and suppression. Opposite changes of active and inactive renin were not observed in the experimental conditions studied.

[Malnutrition and scolastic achievement. Study among the 1st series of 1st grade pupils from the peripheral urban zone of Londrina, P.R., Brazil]

Estudaram-se 450 escolares da periferia de Londrina, PR, Brasil, com o objetivo de demonstrar uma possível associação entre desnutrição e aproveitamento escolar. Destes 450 escolares, 227 eram do sexo masculino e 223 do feminino. A incidência de desnutrição foi de 34,89%. Das crianças desnutridas, apenas 56,69% obtiveram rendimento satisfatório, em comparação aos 73,88% das crianças eutróficas, demonstrando uma relação significativa entre desnuirição e aproveitamento escolar. As crianças desnutridas provinham de famílias com baixa renda mensal bruta per capita em maior proporção que as eutróficas. O aproveitamento escolar mostrou estar mais relacionado ao gasto mensal per capita em alimentação do que a renda mensal bruta per capita.

Studies on the (pro) insulin biosynthesis of islets of Langerhans of sand rats (Psammomys obesus)

By feeding a regular laboratory chow, sand rats (Psammomys obesus) from our breeding colony gained different body weights, though they received approximately the same quantity of calories. Sand rats, reaching a body weight above 160 g (group B) showed significantly increased blood glucose values in contrast to the animals with a body weight under 160 g (group A). Isolated pancreatic islets of these two groups of sand rats were incubated with [3H]-leucine to study the incorporation of this amino acid into proinsulin and insulin. The incorporation into proteins of pancreatic islets of sand rats of group B was stimulated by 0.45 mg and 3.0 mg/ml glucose. In group A there was no further stimulation from 0.45 mg to 3.0 mg/ml glucose. Insulin secretion could be stimulated by glucose in both groups, but the stimulation was stronger in group B than in group A.

Comparison of deaf and hearing children on body-object localization

20 profoundly deaf and 20 normal hearing children from ages 10 to 13 were compared as to their ability to locate visually the position of apparent vertical and the apparent location of the longitudinal axis of the body under erect and 30 degrees left and right body-tilt. Both deaf and normal hearing children were able accurately to locate a rod to the apparent visual vertical, but deaf children were significantly more accurate in aligning a rod to their apparent body-position than hearing children. This finding is discussed from both a learning view and from a hypothesis of developmental lag.

Demonstration of insulin degradation by thiol-protein disulfide oxidoreductase (glutathione-insulin transhydrogenase) and proteinases of pancreatic islets

Homogenate preparations of pancreatic islets have been found to degrade insulin by cleavage of the interchain disulfide bonds, followed by proteolysis of the resulting A and B chains. A proteolytic system of the pancreatic islets splitting not only 125I-labeled insulin A chain but also 125I-labeled glucagon at pH 7.0, was shown to be activated by glutathione and inhibited by EDTA. The results suggest that pancreatic islets contain both the thiol-protein disulfide oxidoreductase (glutathione : protein-disulfide oxidoreductase, EC 1.8.4.2) and the A and B chain-degrading enzyme(s). The effects of EDTA argue against the implication of cathepsins in insulin breakdown under the experimental conditions employed.

[Immuno-prevention of coli infections in swine using live vaccine. 1. Use in coli infections during the 1st days of life]

Live vaccine prepared from streptomycin-dependent mutants of E. coli was well tolerated in various doses and at various times of administration, for there were no adverse reactions. There was no evidence of reversion to a virulent form. Efficacy was closely related to frequency of application of the vaccine. Vaccination must be performed as early as possible to immunize against infection during the first few days of life. It was possible to confer protection against the diarrhoea that occurs at 3-4 weeks of age. The use of an oral vaccine under intensive husbandry systems was shown to be safe. When the piglets were kept in cages, the vaccine could be administered in the existing mixing tanks for water supply, without the need for special equipment. Oral immunization of pigs already infected or already ill did not aggravate the existing infection, whether the animals were housed individually or in pens. Because of the dilution effect of the mixing tank and water supply pipes, the dose of vaccine, given on ten successive days, should be calculated at 10(9) organisms of the E. coli mutant per animal. This should supply a number close to the desired bacterial count of 10(10) organisms per animal daily. Immunization significantly reduced the frequency of gastrointestinal diseases during the first three weeks of age in piglets.

Mixed lymphocyte culture stimulatory and responding capacity of lymphocytes from patients with lymphoproliferative diseases

Lymphocyte reactivity in vitro was studied in patients with Hodgkin's disease, chronic lymphocytic leukaemia and lymphosarcoma. The responding capacity to phytohaemagglutinin (PHA) was markedly depressed and delayed in all three groups of patients compared with the PHA response observed in lymphocyte cultures from normal individuals. In one-way mixed lymphocyte culture experiments a significant decrease in responding capacity of the patients' lymphocytes to lymphocytes from normal donors could be demonstrated. In contrast, the stimulatory capacity of the patients' lymphocytes was found to be intact, or only slightly reduced.

Lymphocyte transformation and production of a human mononuclear leucocyte chemotactic factor in patients with Hodgkin's disease

Human peripheral lymphocytes stimulated in vitro with phytohaemagglutinin (PHA) produce a factor with chemotactic activity for homologous monocytes. The production of this factor and lymphocyte transformation was investigated in patients with Hodgkin's disease. It has been found that the PHA response as measured by incorporation of [³H]thymidine was markedly depressed in patients when compared to the response of normal lymphocytes. In contrast, the production of the chemotactic factor was not significantly depressed in patients with Hodgkin's disease.

Effect of L-asparaginase and hydrocortisone on human lymphocyte transformation and production of a mononuclear leucocyte chemotactic factor in vitro

Human peripheral lymphocytes stimulated in vitro with PHA produce a soluble factor which is chemotactic for homologous monocytes. The synthesis of this factor was found to precede the blastogenic response as measured by [³H] thymidine incorporation. In cultures of unseparated leucocytes the maximum of chemotactic activity was detected after 24 hr, whereas in supernatants from purified lymphocyte suspensions the maximal synthesis occurs after 72 hr. High doses of L-asparaginase from E. coli which have been found to prevent lymphocyte transformation completely have no influence on the production of the chemotactic factor. Therefore it seems possible that the induction of DNA synthesis by PHA and its effect on the production of a chemotactic factor depend on different biochemical mechanisms. In contrast hydrocortisone leads to a dose-dependent inhibition of both DNA synthesis and chemotactic response.

Effects of hydrocortisone treatment and whole body irradiation on mouse lymphocyte stimulation in vitro

Whole body irradiation was found to reduce the number of nucleated cells in the thymus and the spleen of C57B1 mice to the same extent as hydrocortisone treatment. Equal numbers of thymus and spleen cells from either hydrocortisone-treated or irradiated mice and matched controls were cultured and stimulated with various mitogens. An increased stimulation of DNA synthesis by PHA, Con A and PWM was found in thymus and spleen cells after hydrocortisone treatment as well as after whole body irradiation. In contrast, the response to LPS, known as a typical B-cell mitogen, was not affected by any of the procedures.