Diabetes in pregnancy. Skeletal malformations in the offspring of diabetic rats after intermittent withdrawal of insulin in early gestation.

Precise timing of the teratogenic period in diabetic pregnancy is of clinical importance since correction of the glucose intolerance during this period may protect the offspring from malformations. An experimental approach to elucidate this problem with regard to skeletal development was made in groups of pregnant streptozotocin-diabetic rats (MDI), which were treated with daily insulin injections except for a 2-day period in the first half of pregnancy. The degree of metabolic derangement was estimated by measurements of serum glucose concentrations. During the insulin-free period, the rats showed severe hyperglycemia (greater than 20 mM) while during ongoing insulin treatment, only brief periods of hyper- or hypoglycemia were observed. Insulin treatment was withdrawn successively between gestational days 3 and 12. Control groups consisted of normal pregnant rats (N) or pregnant rats with manifest diabetes (MD) without insulin treatment. The serum glucose levels of the N animals were below 6 mM while those of the MD animals were above 25 mM throughout pregnancy. Skeletal malformations in the viable offspring were recorded on gestational day 20 after Alizarin staining of calcified ossification centers, which also allowed an estimate of skeletal development as a whole. Untreated diabetes in the MD rats induced a high rate of fetal resorptions, a decrease in fetal weight and viability, as well as retardation of skeletal development. Intermittent insulin treatment in the MDI rats ameliorated, but did not abolish, these changes. In the MD group 9 of 48 viable fetuses showed severe malformations of either the lower jaw (micrognathia) or of the lumbosacral region (caudal dysgenesis).(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of free and total insulin and C-peptide in insulin-treated diabetics.

Serum levels of free and total insulin as well as total C-peptide immunoreactivity (C-peptide and proinsulin) and C- peptide were measured in insulin-treated diabetics with circulating insulin antibodies by the addition of polyethylene glycol (PEG) before and after acidification. PEG resulted in complete precipitation of insulin antibodies from serum and made it possible to measure free insulin in the supernatant. Incubation of serum at 37 degrees C. for two hours before addition of PEG resulted in values for free insulin that probably resembled the in-vivo levels most closely. The same method could also be used to remove proinsulin bound to circulating insulin antibodies and permitted the measurement of C-peptide in the supernatant. Clinical studies using this approach indicate that combined measurements of serum free and total insulin and C-peptide provide information that is helpful in understanding the contribution of endogenous and exogenous insulin to the course and metabolic control of insulin-requiring diabetic patients.

Polymerization of fetal fibrin and alterations in fibrin network characteristics during diabetic pregnancy.

The present study compares plasma fibrin network characteristics of fetal blood and that of normal and diabetic pregnant women. Plasma fibrinogen concentration, clotting curves, mass-length ratio of the fibrin fibers, gross permeability and tensile strength of the networks, have been measured. Plasma glucose and glycated hemoglobin are used as glycemic index in diabetic gestational women. The fetal plasma has a lower concentration of fibrin and exhibits delayed clotting, the networks are made up of thinner fibers, are more cross-linked, have lower permeability, and increased tensile strength than in normal adults. The tensile strength of the networks prepared from the plasma of diabetic gestational women are more highly crosslinked than those made from plasma of normal women of corresponding length of pregnancy. The fibrin fiber-thickness is increased during the first and second trimester but is significantly reduced during the third trimester in the diabetic gestational women. The gross permeability of the networks is significantly reduced during the second and third trimester in the diabetic gestational women. The SDS-PAGE shows characteristic pattern of alpha, beta, and gamma-polypeptides in both normal and diabetic gestational women.

Enamel hypoplasia in a litter of rats with alloxan-induced diabetes mellitus.

Enamel hypoplasia is an important clinical problem commonly seen in children born to diabetic women. We aimed to characterize the enamel hypoplasia in Wistar rats born to alloxan-induced diabetes mellitus rats. Groups consisted of pregnant rats supplemented (ISDR) or not (NISDR) with insulin and controls, in which sterile saline solution was administered instead of alloxan or insulin. The mandibular incisors of one-month-old rats born to these mothers were analyzed. Whitish defective enamel was found macroscopically in both experimental groups (ISDR = 37.5%, NISDR = 33.3%) but not in the control group. Mild to severe enamel hypoplasia was observed by scanning electron microscopy (ISDR = 93.8%; NISDR = 100%, control = 4.2%). The severity of hypoplasia correlated positively with the maternal level of blood glucose. In conclusion, the intensity of enamel hypoplasia in the teeth of the litter born to alloxan-induced diabetic rats was variable and was dependent on the glycemic level of the pregnant rat.

Diagnosis of gestational diabetes by use of a glucose polymer.

The oral glucose tolerance test is the recommended method for the assessment of carbohydrate metabolism in pregnancy. However, available glucose drinks are often associated with varying degrees of gastrointestinal symptoms that might preclude meaningful studies. Polycose (Ross Labs, Columbus, Ohio) is a glucose saccharide polymer mixture containing 3% glucose, 7% maltose, 5% maltotriose, and 85% polysaccharide of 4 to 15 glucose units, with an osmotic load one fifth that of glucose. We assessed the efficacy of this glucose polymer in the performance of a 3-hour carbohydrate tolerance test with glucose and glucose polymer used 3 to 5 days apart in each patient tested. After 2 days of 300 gm carbohydrate-enriched diets, 48 patients underwent 3-hour carbohydrate tolerance tests at a mean gestational age of 30 +/- 3 weeks. Statistical analysis revealed a moderate level of agreement (kappa = 0.45, p less than 0.001) between the results of both carbohydrate tolerance test preparations. Patients experienced fewer gastrointestinal symptoms with the glucose polymer than with glucose. These preliminary data suggest that glucose polymer may be effectively used in the performance of a 3-hour carbohydrate tolerance test.

Vitamin E and A and periodontium in pregnant diabetics.

The authors followed physiological levels of vitamin E and A in four-week intervals in the course of physiological pregnancy in 11 insulin dependent diabetics. The highest mean levels of both vitamins were found in the IIIrd trimester. Simultaneously, the periodontal condition and the standard of oral hygiene were evaluated by means of epidemiological indexes in two-week intervals. The most marked inflammatory changes of periodontium occurred in the 8th month and were followed by an improvement before delivery, though the standard of oral hygiene was unchanged. The possibility of the eventual contribution of both vitamins in the improvement of periodontal condition in the final stage of pregnancy seems evident.

In vitro effects of glucose and growth factors on limb bud and mandibular arch chondrocytes maintained at various serum concentrations.

In human and experimental diabetic pregnancy there is an increased risk of congenital malformation in the offspring. Some malformations involve growth retardation and altered chondrocyte differentiation, suggesting that a diabetic milieu may modify embryonic cell replication and the development of (pre)chondrocytes. The aim of the present work was to study the effects of a diabetes-like environment in vitro on the growth and differentiation of rat chondrocytes in the presence of specific growth factors and different concentrations of serum. This was performed with a modified micromass culture system of embryonic (pre)chondrocytes from the limb bud and mandibular arch areas using medium supplemented with different glucose concentrations and with serum from diabetic rats. An elevated ambient glucose concentration inhibited the growth of mature chondrocytes in vitro, and this effect was diminished in a serum-rich culture milieu. The (pre)chondrocytes exhibited a marked dependence on the serum level in the culture medium for optimal in vitro development. Diabetic rat serum had the lowest stimulatory capacity of the three different types tested (at similar glucose concentrations), suggesting a deficiency of growth-stimulating factor(s) rather than the presence of inhibiting factor(s) in this type of serum. One of the deficient factor(s) in diabetic rat serum may be similar to IGF-II, but a combined deficiency of several growth-stimulating agents is likely to be present. Chondrocytes originating from the mandibular arch in general appeared more sensitive to MSA and IGF-II than those from the limb buds. The present observations support the notion that while diabetes-induced hyperglycemia in the conceptus contributes to severe growth retardation of the mandibular arch, additional factors also play a role.

Are there structural alterations in the enamel organ of offspring of rats with alloxan-induced diabetes mellitus?

Enamel hypoplasia is the most common developmental defect of human teeth that may be seen in deciduous teeth of babies born to diabetic women. In the present experimental study, we analyzed the enamel organ of the mandibular incisors of the offspring of rats with alloxan-induced diabetes. By light microscopy, no alterations could be found in the enamel organ of rats born to diabetic mothers compared to normal ones, except in one case. In contrast, significant differences were detected with computer-aided morphometry. In the rats born to treated and untreated diabetic mothers, there was thinning of the enamel matrix and of the ameloblasts and the nuclear area of the latter was smaller. In the rats born to treated diabetic mothers, the nuclei of the ameloblasts were more elliptical and there was enlargement of the interstitial area of the stellate reticulum. These results indicate that there are structural defects in the enamel organ of rats born to mothers with alloxan-induced diabetes which could induce the enamel hypoplasia observed by scanning electron microscopy and which may reflect the metabolic alterations seen in this condition. Future studies are needed to determine whether these effects are transitory or permanent.

Enamel hypoplasia in a litter of rats with alloxan-induced diabetes mellitus

Enamel hypoplasia is an important clinical problem commonly seen in children born to diabetic women. We aimed to characterize the enamel hypoplasia in Wistar rats born to alloxan-induced diabetes mellitus rats. Groups consisted of pregnant rats supplemented (ISDR) or not (NISDR) with insulin and controls, in which sterile saline solution was administered instead of alloxan or insulin. The mandibular incisors of one-month-old rats born to these mothers were analyzed. Whitish defective enamel was found macroscopically in both experimental groups (ISDR = 37.5 percent, NISDR = 33.3 percent) but not in the control group. Mild to severe enamel hypoplasia was observed by scanning electron microscopy (ISDR = 93.8 percent; NISDR = 100 percent, control = 4.2 percent). The severity of hypoplasia correlated positively with the maternal level of blood glucose. In conclusion, the intensity of enamel hypoplasia in the teeth of the litter born to alloxan-induced diabetic rats was variable and was dependent on the glycemic level of the pregnant rat

Are there structural alterations in the enamel organ of offspring of rats with alloxan-induced diabetes mellitus?

A hipoplasia de esmalte é a mais comum dentre as alterações de desenvolvimento do dente humano, e ocorre com freqüência em dentes decíduos de filhos de mães diabéticas. O presente estudo experimental analisou, por meio de microscopia óptica e morfometria, o órgão do esmalte de incisivos inferiores de filhotes de ratas com diabetes aloxânico, induzido previamente à gestação. Os resultados mostraram que não foram observadas pela microscopia óptica alterações significantes nos germes dentais dos animais descendentes de ratas diabéticas, com exceção de um caso. A análise morfométrica dos órgãos do esmalte de ratos nascidos de mães diabéticas tratadas e não tratadas evidenciou as seguintes diferenças estatisticamente significantes: menor espessura da matriz de esmalte, menor altura dos ameloblastos e área de seus núcleos. Nos animais nascidos de ratas diabéticas tratadas, observou-se núcleos dos ameloblastos mais elípticos e aumento da área correspondente ao interstício do retículo estrelado. Estes resultados indicam que há alterações estruturais no órgão do esmalte de descendentes de ratas com diabetes aloxânico as quais poderiam induzir a hipoplasia do esmalte dental visto por microscopia eletrônica de varredura, possivelmente refletindo as alterações metabólicas observadas nesta condição. Estudos futuros devem ser realizados a fim de determinar se estas alterações são transitórias ou permanentes.