Intracytoplasmatische Glykogenablagerungen,lamelläre Strukturen und virus-ähnliche Einschlüsse in Mastzellentumoren des Hundes. Eine elektronenmikroskopische Untersuchung

Zusammenfassung Gefunden wurden: Bis zu 6 große Einschlüsse, welche aus Glykogenkörnchen bestehen; rundliche, bis zu 1,5 große, aus Lamellen zusammengesetzte Strukturen; virusähnliche Partikel (30–32 m), die einzeln oder zu mehreren in membranumgebenen Haufen liegen.

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Intracytoplasmatic glycogen deposits, lamellate structures and virus-like inclusions in mast-cell tumours of dogs. An electron-microscopic study

Summary The following were encountered: inclusions measuring up to 6 and composed of glycogen grains; round structures measuring up to 1.5 , and consisting of laminae; viruslike particles (30–32 m) either occurring as single bodies or accumulations. The latter were surrounded by a single membrane.

     

Cytogenetic effects of N-nitrosodiethanolamine (NDELA) and NDELA-monoacetate in human lymphocytes

Summary The mutagenicity of N-nitrosodiethanolamine (NDELA) and NDELA monoacetate was tested in vitro on lymphocytes of two healthy probands by determining the frequencies of chromosome aberrations, micronuclei and sister chromatid exchanges (SCE). A dose-dependent increase was found in all three test systems for NDELA as well as its monoacetate. The SCE test proved to be most sensitive for the genotoxic effect of NDELA because the differences to the control cultures had already become significant at 250–625 mol/culture (26.6–65.4 mM). However, NDELA monoacetate showed a higher reactivity in the micronuclei and chromosome aberration test: significantly increased values were found even at 12.5 mol (1.3 mM), whereas in the SCE test the differences became significant at the 25-mol (2.7 mM) level. NDELA caused significantly increased rates of micronuclei and chromosome aberrations only at the highest test levels (625–1250 mol; 65.4–127.6 mM). The results indicate important differences in the genotoxic effects of the two compounds, which might be explained by different lipophilicity and/or special activation processes.     

Iron stores in 1359, 30- to 60-year-old Danish women: Evaluation by serum ferritin and hemoglobin

Summary Iron status, including serum (S-)ferritin and hemoglobin (Hb), was assessed in a population survey comprising 1359 nonpregnant Danish women in age cohorts of 30, 40, 50, and 60 years. S-ferritin levels were similar in 30- and 40-year-old women; they displayed a significant increase in 50-year-old women and a further significant increase in 60-year-old women. In the 30- and 40-year-old women, median S-ferritin was 38g/l, 5–95 percentile 6–135g/l; 17.2% had values < 15,g/l (i.e., depleted iron stores), 22.7% values from 15 to 30g/l (i.e., small iron stores), and 60.1% values > 30g/l (i.e., replete iron stores). In the 50-year-old women, median S-ferritin was 54g/l, 5–95 percentile 10–164g/l; 10.3% had values < 15g/l, 16.5% values from 15 to 30g/l, and 73.2% values > 30g/l. For the 60-year-old women, median S-ferritin was 84g/l, 5–95 percentile 25–249g/l; 1.6% had values < 15g/l, 8.6% values from 15 to 30g/l, and 89.8% values > 30g/l. Blood donors (n=180) had lower S-ferritin than nondonors in all age-groups (p<0.001). In the entire series, Hb levels were similar in 30- and 40-year-old women, median 137 g/l (8.5 mmol/l), 5–95 percentile 121–152 g/1 (7.5–9.4 mmol/l), and higher in 50- and 60-year-old women, median 140 g/l (8.7 mmol/l), 5–95 percentile 123-158 g/l (7.6–9.8 mmol/l) (p<0.0001). Hb values < 121 g/l (7.5 mmol/l) were observed in 3.8% of the women. Women with S-ferritin < 15 g/l (n=161) had lower Hb, median 134 g/l (8.3 mmol/l), than those with S-ferritin > 15 g/l, median 139 g/l (8.6 mmol/l) (p<0.001). Iron deficiency anemia (S-ferritin < 15 g/l and Hb < 121 g/l) was seen in 2.3% of 30- and 40-year-old women, and in 1.1% of 50- and 60-year-old women.     

Pancreatic Fluid Hypersecretion in Rats After Acute Pancreatitis

Pancreatic exocrine function was examined inrats during the early stage of acute pancreatitisinduced by four subcutaneous injections of 20 mug/kgbody weight of cerulein at hourly intervals. Basalpancreatic fluid secretion at 6 hr after the first of fourcerulein injections was significantly elevated (27.6± 3.7 vs 17.4 ± 2.1 l/30 min incontrol, P < 0.01) and further increased with time,reaching the peak level at 24 hr (105.1 ± 4.6 l/30 min).Intravenous infusion of loxiglumide (50 mg/kg bodywt/hr), atropine (100 g/kg body wt/hr), oranti-secretin serum did not modify the fluidhypersecretion observed at 24 hr after induction of acute pancreatitis.Loxiglumide, when given 30 min before the first ceruleininjection, markedly reduced fluid secretion, but couldnot inhibit the fluid hypersecretion when applied after the last cerulein injection. Leakage ofEvans blue dye into pancreatic juice was slightly butsignificantly increased in postpancreatitic ratscompared with that in the control rats (1.30 ±0.17 vs 0.75 ± 0.08 g/ml, P 0.01),whereas that in the pancreas was not different from thecontrol rats. In vivo labeling with5-bromo-2-deoxyuridine showed active proliferation ofacinar and ductular cells at 6 hr. In addition, the fluid was rich inchloride (137.1 ± 2.5 at 24 hr vs 92.4 ±3.3 meq/liter in control, P < 0.01) but poor inbicarbonate concentration (39.0 ± 2.0 at 24 hr vs46.5 ± 1.9 mmol/liter in control, P < 0.01), indicating acinar cell secretion.These results indicate that pancreatic fluid secretionduring the early stage of acute pancreatitis induced bysupramaximal doses of cerulein was markedly increased not by CCK-, secretin-, orcholinergic-dependent mechanisms but probably by acinarcell proliferation.     

Fasting prevents acute pancreatitis induced by cerulein in rats

We examined the effect of fasting on the course of experimental acute pancreatitis induced in rats by four subcutaneous injections of 20 g/kg body weight of cerulein at hourly intervals. Rats were either fasted from 24 hr before to 9 hr after the first cerulein injection or fed ad libitumthroughout the experiment. Twenty-four hours of fasting reduced cerulein-induced increases in serum levels of amylase and anionic trypsin(ogen) to 50 and 70% of those in fed rats, respectively. Increases in pancreatic wet weight after cerulein injections were also less in fasted rats than in fed rats. Pancreatic content of trypsin was significantly decreased after a 24-hr fast, and no further changes were induced by cerulein injections. The histological signs of acute pancreatitis were greatly alleviated by fasting. However, 24 hr of fasting did not alter the sensitivity and responsiveness of the exocrine pancreas to cerulein in both in vivoand in vitro.Plasma CCK bioactivity and immunoreactive secretin concentration in 24-hr-fasted rats were significantly lower than those in fed rats. Administration of CCK receptor antagonist, loxiglumide, 12 hr prior to the induction of acute pancreatitis reduced the increase in serum amylase activity in fed rats to nearly the same levels as that in fasted rats and alleviated histological signs of pancreatitis to some extent. These present observations suggest that fasting lessens the severity of cerulein-induced acute pancreatitis by reducing endogenous CCK release.This work was supported in part by a grant from the Japanese Ministry of Health and Welfare and Grant-in-Aid for Scientific Research (C).     

Serum bile salts as an aid to oral cholecystogram interpretation

A radioimmunoassay for glycocholate was used as an estimate of serum bile salts in patients with serum bilirubin levels less than 5 mg/dl undergoing oral cholecystography. Most subjects also had a percutaneous liver biopsy. Intravenous cholangiography was performed in most subjects who had a nonvisualized gallbladder after receiving single doses of iopanoic acid on two consecutive days. The pathologic status of nonvisualized gallbladders was ascertained by surgery, prospective follow-up, necropsy and/or ultrasound. In 20 subjects with well-visualized gallbladders, the serum cholate conjugates (CC) were lower than 3.5 M in all but two subjects, both of whom had inflammatory liver disease (chronic active hepatitis, alcoholic hepatitis). Those with faintly or poorly visualized gallbladders, but with no evidence of gallbladder or gallstone disease by other criteria, also had levels less than 3.5 M, except for one subject with inflammatory liver disease. By contrast, 11 subjects with nonvisualized, although normal gallbladders by the above clinical criteria, exhibited serum CC greater than 3.5 M. Six subjects had diminished gallbladder visualization, but normal gallbladders on clinicopathological grounds; all but one with chronic active hepatitis had serum CC greater than 3.5 M. In conclusion, when the serum cholate conjugates are less than 3.5 M, nonvisualization of the gallbladder with oral cholecystography supports a diagnosis of a diseased gallbladder. In addition, a serum CC level greater than 3.5 M may predict insufficient hepatic capacity to secrete iopanoic acid adequate for gallbladder visualization in noninflammatory liver disease. The serum cholate conjugates appear to provide greater information on this hepatic function than the serum bilirubin or bromsulfophthalein retention.     

Maturation of villus and crypt cell functions in rat small intestine

To evaluate the role of dietary polyamines in maturation of the rat small intestine, spermine was given orally twice daily to suckling pups from day 10 to day 14 postpartum at different doses: 0, 0.2, 0.5, 1, 2.5, and 5 mol/dose. Compared, to saline treated controls, spermine (5 mol) produced significant increases in mucosal mass parameters (+12 to +57%,P<0.05), induced prematurely, an adult pattern of microvillous enzymes, and enhanced respectively, by 19- and 3.5-fikd (P<0.01 vs controls) the concentration of the secretory component ofp-immunoglobulins in villous and crypt cells. The response of microvillous enzymes (lactase, sucrase, maltase, and aminopeptidase) to spermine was dose-dependent and-specific since oral administration of arginine (5 mol) or ornithine (5 mol) was without effect. Intestinal changes were found to be significant (P<0.05) for doses of spermine exceeding 1 mol/day, which is in the range of the amount of polyamines provided by solid pellets at weaning (0.4 mol/g). However, intestinal changes were undetectable at the physiological amounts of polyamines consumed by pups from rat milk during the suckling period (less than 0.3 mol/day). Consistent with a direct effect of spermine on the intestinal cell, the cytosolic activity of ornithine decarboxylase was depressed by 27-fold (P<0.005 vs controls) in the jejunum, while inhibition of ornithine decarboxylase by -difluoromethylornithine did markedly decrease but did not suppress the cell response to spermine. Alternately, plasma corticosteronemia, which was virtually, absent by day 14 in controls, ranged between 1.4 and 4.6 g/dl in 60% (N=9) of the spermine-treated rats. These novel findings indicate that dietary polyamines exert direct and indirect trophic effects on the rat immature intestine and can trigger at a critical level of intake the adult expression of villus and crypt cell functions.     

Sertraline Causes Strong Coronary Vasodilation: Possible Relevance for Cardioprotection by Selective Serotonin Reuptake Inhibitors

Summary Objective: Although Selective Serotonin Reuptake Inhibitors (SSRIs) are important antidepressant drugs, knowledge of their vaso active effects is limited. Vaso active effects of the SSRI sertraline were studied in rings of rat aorta, human Internal Mammary Arteries (IMAs) and in Langendorff perfused rat hearts.Methods: The effects of sertraline (0.1 to 300 mol L^{– 1}) on precontracted rat aortic and IMA rings were evaluated in organ bath chambers. Precontraction was elicited by serotonin (5-HT; 10 mol L^{– 1}), phenylephrine (PE; 10 mol L^{– 1}) and potassium chloride (KCl; 50 mmol L^{– 1}). In addition, the effects of sertraline on PE induced contraction curves were established by subjecting vascular rings to increasing doses of PE (1 nmol L^{– 1} to 10 mol L^{– 1}) in the presence of sertraline or vehicle. Finally, the effects of sertraline on ex vivo coronary flow in rat hearts were examined using a retrograde Langendorff perfusion model.Results: Sertraline elicited dose-dependent relaxation, independent of the substance used for precontraction (p < 0.025). Sertraline showed a rightward shift of dose-response curves to PE (p < 0.01). Vasodilatory effects of SSRIs were endothelium independent. In perfused rat hearts, sertraline (0.3 to 10 mol L^{– 1}) showed a concentration-dependent increase in coronary flow that returned to baseline levels after wash-out of the antidepressant (p = 0.005).Conclusions: One of the SSRIs, sertraline, showed marked vasodilatory effects in rat aorta and human IMAs. Sertraline elicited vasodilatation in coronary arteries during perfusion of rat hearts. These hemodynamic effects may explain the observed beneficial effects in myocardial ischemia and infarction.     

High plasma leucine concentrations without neurological symptoms in a patient with classical maple syrup urine disease

It has been found that the amino acid analyser used in this study systematically overestimated plasma leucine at high concentrations. The concentration reported as 2249 mol/L had a true value of 1430 mol/L and leucine values reported as >2000 mol/L were approximately 1500 mol/L.     

The Role of the MAP-Kinase Superfamily in β-Amyloid Toxicity

The mitogen-activated protein kinase (MAP kinase) pathway participates in a number of reactions of the cell when responding to various external stimuli. These stimuli include growth factor binding to its receptor as well as stressful situations such as hypoxia and oxidative stress. It has been postulated that one of the mechanisms by which -amyloid exerts its toxic effects is to produce oxidative stress. This study therefore investigated whether the MAP-kinase pathway was activated in cells following exposure to -amyloid. Neuroblastoma (N2) cells were used in all experiments. The cells were exposed to 50, 100, and 500 M glutamate, and 10, 30, and 50 M -amyloid, for 24 h. The methyl–thiazolyl tetrazolium salt (MTT) assay was performed to determine the degree of toxicity. The generation of hydrogen peroxide was detected by fluorescence microscopy using the dye dihydrochlorofluorescein diacetate (DCDHF). Extracellular-signal-regulated kinase (ERK) and p38 MAP-kinase phosphorylation, as representatives of the MAP-kinase pathway, was determined. Treating N2 cells with -amyloid resulted in a greater than 50% reduction in cell viability. These cells also showed a significantly higher presence of hydrogen peroxide. Western Blot analysis revealed that the phosphorylation of p38 MAP kinase was dose-dependently increased in cells exposed to glutamate and -amyloid. On the other hand, the phosphorylation of ERK was significantly reduced in these cells. These data therefore suggest that the toxic effects of -amyloid involve the generation of hydrogen peroxide, leading to the activation of p38 and the down-regulation of ERK.     

Influence of phorbol esters on contractile force,action potential and calcium current of isolated guinea-pig heart tissues

Phorbol-12,13-dibutyrate (PDB) reduced concentration-dependently the contractile force of guineapig papillary muscles (EC₅₀ 1.07 mol/l) while phorbol-12-myristate-13-acetate (PMA) was ineffective. The protein kinase C inhibitors staurosporine (0.1 mol/l) and polymyxin B (70 mol/l) did not antagonize the negative inotropic effect of PDB. Neither PMA nor PDB, in concentrations up to 30 mol/l caused significant changes of the membrane resting potential, the maximum depolarization velocity, the action potential duration or the functional refractory period in intact papillary muscles. In isolated ventricular cardiomyocytes the inward calcium current was halved by either 1 mol/l PDB or 10 mol/l PMA. PKC inhibitors attenuated, but could not completely abolish this effect of the phorboles. It is concluded that the negative inotropic effect of PDB is caused by a reduction of the slow inward calcium current and that this inhibition is, for the greater part, not mediated by an activation of protein kinase C.     

Dose/response study of the effects of oestrogens on tumour growth and morphology in the Dunning R3327 prostatic adenocarcinoma

Summary The present study was undertaken to investigate to what extent the oestrogen-induced effects on growth and morphology of the Dunning R3327 rat prostatic adenocarcinoma are dose-dependent. Castrated and testosterone-supplemented rats were used in order to study effects of increasing doses of oestrogens on the tumour. It was found that the lowest dose of oestradiol-17 that reduced the overall growth, the volume density of the epithelium and epithelial cell area in Dunning R3327 prostatic tumours is 10 g given as daily injections. Higher oestrogen doses (50 g, 200 g, and 500 g), in addition to reducing the volume of tumour epithelium, also induced an increase of the volume density of tumour stroma. The area of stroma cell nuclei was increased by 50 g and 200 g oestradiol-17. These observation, may indicate that the lowest effective oestrogen dose is different in the epithelium and stroma of Dunning tumours and that large doses of oestrogen stimulate the stromal compartment. This stimulatory effect did not influence the inhibitory effects seen on the overall growth of the tumour and on the tumor epithelium.     

Pharmacological evidence for beta3 adrenoceptors in the control of rat gastric acid secretion

The effect of the ₃-adrenoceptor agonist BRL37344 on gastric acid secretion evoked by different secretory stimuli was investigated in anaesthetized rats with lumen-perfused stomachs in comparison with the ₂-adrenoceptor agonist clenbuterol. Intravenous injections of BRL37344 (1–10 mol/kg) and clenbuterol (0.01–1 mol/kg) dose-dependently reduced 2-deoxy-D-glucose-induced acid secretion, with BRL37344 about forty times less potent than clenbuterol. BRL37344 (0.1–3 mol/kg) inhibited pentagastrin-induced acid output, whereas clenbuterol was effective only at high doses (10–100 mol/kg). The inhibitory effect of BRL37344 on pentagastrin-induced acid secretion was not modified by the nonselective –adrenoceptor antagonist propranolol, but it was prevented by bupranolol, a ₃-adrenoceptor antagonist. Furthermore, neither BRL37344 (10 mol/kg) nor clenbuterol (100 mol/kg) modified the acid secretion induced by histamine. These data suggest that ₃ adrenoceptors have an inhibitory role in the control of rat gastric acid secretion induced by indirect stimuli.     

Sarcophytols A and B inhibit tumor promotion by teleocidin in two-stage carcinogenesis in mouse skin

Summary Sarcophytols A and B, isolated from a soft coral, Sarcophyton glaucum, are cembrane-type diterpenes with different numbers of hydroxyl groups. Sarcophytols A and B inhibited tumor promotion by teleocidin in two-stage carcinogenesis experiments on mouse skin. The inhibitory effect of sarcophytol A was demonstrated with two different initiating doses of 7,12-dimethylbenz[a]anthracene (DMBA): 50 g (experiment 1) and 100 g (experiment 2). In experiment 1, three groups of mice were treated with DMBA, and then twice a week with doses (1.6 g, 16 g, and 82 g) of sarcophytol A followed by 2.5 g teleocidin. In week 25, the incidences of tumors in these groups were only 7.1%, 20.0%, and 13.3%, respectively, whereas that in the control group treated with DMBA plus teleocidin was 53.3%. Moreover, at this time, the average numbers of tumors per mouse in these groups were 0.1, 0.3, and 0.3, respectively, while that in the control group was 2.1. In experiment 2 an amount of sarcophytol A (1.6 g) or B (1.7 g) equimolar to 2.5 g teleocidin was applied twice a week, as in experiment 1, and results showed that sarcophytol B also inhibited tumor promotion by teleocidin. Both sarcophytols A and B caused delay in onset of tumor formation, and reduced the percentage of tumor-bearing mice and the average number of tumors per mouse. The effective concentrations of sarcophytols A and B were in the microgram range with an equimolar amount of teleocidin.Abbreviations DMBA 7,12-dimethylbenz[a]anthracene - TPA 12-O-tetradecanoylphorbol-13-acetate     

Islet B-cell dysfunction and the time course of recovery following chronic overinsulinisation of normal rats

Summary Appropriate insulin therapy may preserve or improve islet B-cell function whereas the effects of overinsulinisation are unclear. Pancreatic islet B-cell function was therefore studied after overinsulinisation of normal rats for 4 weeks (fed blood glucose 2.2–4.5 mmol/l, controls 4.1–7.0 mmol/l). Insulin secretion was assessed by a 3-h hyperglycaemic clamp (10.0 mmol/l) performed 1, 48, and 120 h after insulin withdrawal (n=6 in each group). When the clamp was performed 1 h after insulin withdrawal, clamp insulin concentration was 1.6±0.1 g/l, compared to 9.3±1.0 g/l in control rats. The integrated area under the plasma insulin concentration curve was also significantly decreased (4.8±0.4 vs 20.3±2.2 g·l^–1·h^–1, p<0.001), but recovered to 9.4±1.0 g·l^–1·h^–1 after 48 h, and to 17.5±1.4 g·l^–1·h^–1 after 120 h. Pancreatic insulin contents were decreased at 1 h (6±1 g/g wet wt) and 48 h (54±12 g/g wet wt) but not at 120 h (221±30 g/g wet wt) after withdrawal (controls, 303±29 /g wet wt) and there was a strong relationship with pancreatic preproinsulin mRNA and the clamp insulin response. Thus, overinsulinisation with prolonged periods of low blood glucose concentrations impairs islet B-cell function, but is reversible over 5 days.     

Cholecystokinin stimulates growth of human pancreatic adenocarcinoma SW-1990

The effect of a synthetic analogue of CCK (Thr⁴,Nle⁷CCK-9) on growth of SW-1990 human pancreatic cancer was examined in two experimental models. Nude mice bearing SW-1990 pancreatic cancer xenografts were injected with CCK (5, 15, or 25g/kg) or vehicle twice daily for 20 days. Animals were then sacrificed and tumor volume, weight, protein, and deoxyribonucleic acid (DNA) content were evaluated. SW-1990 cells were grown in vitro and the effects of CCK, secretin, vasoactive intestinal peptide (VIP), and proglumide (a CCK-receptor antagonist) on cell number and DNA synthesis were determined. The highest dose of CCK, 25 g/kg, significantly increased tumor weight, protein content, and DNA content P<0.005). In vitro, CCK caused significant increases in cell counts of up to 47% at six days and 66% at 12 days compared to control. Graded concentrations of CCK had a biphasic effect on DNA synthesis with significant increases of up to 65% P<0.005). CCK-induced cell proliferation was inhibited by proglumide. Secretin slightly increased cancer cell growth, although not as potently as CCK. VIP or secretin in combination with CCK did not show potentiation. These results indicate that growth of some human pancreatic cancers may be influenced by gastrointestinal peptides, of which CCK is the most potent.This work was supported by Grant IN-109L from the American Cancer Society, grants DK35152 and CA50303-01 from the National Institutes of Health, and by the Research Services of the Veterans Administration.     

Serumeisen-Normalwerte und statistische Verteilung der Einzelwerte bei Mann und Frau

Zusammenfassung Die Bestimmung der Normalwerte des Serumeisen bei 608 Erwachsenen und die Untersuchung des Verteilungstyps der Einzelwerte zeigt folgende Ergebnisse: Bei 503 Männern beträgt der Mittelwert (als arithmetisches Mittel) 109 g Fe/100 ml ±25 und der Normalbereich (als ±2 SD-Bereich) 59 bis 158 g Fe/100 ml, bei 105 Frauen 91 g Fe/100 ml±27 als Mittelwert und 37 bis 145 g Fe/100 ml als Normalbereich. Die Untersuchung der Verteilung mittelsFisher- undKolmogoroff-Test führte zur Annahme, einer näherungsweisen Normalverteilung.

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Summary The determination of normal values of serum iron in 608 adults and the examination of the frequency distribution gives the following results: the arithmetic mean in 503 male persons is 109±25 g Fe/100 ml and the normal range (2-SD-range) 59 to 158 g Fe/100 ml; in 105 female persons 91±27 g Fe/100 ml mean and 37 to 145 g Fe/100 ml normal range. The assumption of approximate normal distribution are controlled by theFisher- andKolmogoroff-test.

     

Cellular ionic effects of insulin in normal human erythrocytes: a nuclear magnetic resonance study

Summary Elevated erythrocyte cytosolic free calcium, and suppressed free magnesium and pH values are associated with the hyperinsulinaemia and insulin resistance of hypertension, obesity, and Type 2 (non-insulin-dependent) diabetes mellitus. To determine the role of insulin in this process, we utilized ¹⁹F- and ³¹P-nuclear magnetic resonance spectroscopy to study the cellular ionic effects of insulin in vitro on normal human erythrocytes. Insulin elevated cytosolic free calcium levels in a dose- and time-dependent manner. The effect began at 10 U/ml, peaked at 200 U/ml, and continued at both the 500 U/ml and 1000 U/ml doses. At 200 U/ml, free calcium levels rose from 24.6±2.5 nmol/l to a peak value at 120 min of 66.4±11 nmol/l (p<0.05 vs basal), levels remaining elevated throughout the incubation (45.7±5.6 nmol/l at 60 min, and 47.9±9.1 nmol/l at 180 min, p<0.05 vs basal, respectively). Similarly, insulin also increased intracellular free magnesium at all time points (basal: 177± 11 mol/l; 60 min: 209±19 mol/l; 120 min: 206±22 mol/l; and 180 min: 202±12 mol/l; p<0.05 vs basal at all times). No insulin-induced changes in pH were observed. We conclude (i) that insulin in physiological concentrations may participate in regulating divalent cations in the mature human erythrocyte, (ii) that insulin per se cannot account for the previously described cellular ionic lesions of hypertension and diabetes, and (iii) that future clinical studies of cell ion metabolism should be conducted in the fasting state, be controlled for ambient circulating insulin levels, or both.     

Insulin levels in the umbilical vein and in the umbilical artery of newborns of normal and gestational diabetic mothers

Summary Insulin levels (by double antibody radioimmunological assay) were studied in the venous blood of mothers at vaginal delivery and in the umbilical vein and artery of their newborns. — In 14 normal mothers the insulin levels after 10 hours fasting were 18.5±3.6 U/ml (mean±S.E.M.). In their newborns (mean: 3.420 kg, all < 4.000 kg, 38–41 weeks gestation) the insulin levels were low and similar in the umbilical vein (5.6±0.7 U/ml) and in the umbilical artery (6.6±0.7 U/ml). The plasma glucose levels in the mothers were 99.7±3.9 mg/100 ml and in the umbilical vein 77.3±3.7 mg/100 ml and the umbilical artery 65.5±3.2 mg/100 ml. They were significantly different from each other. — Eleven normal mothers receiving a glucose infusion (ca. 15 g/3 hours) during delivery had 42.0±9.9 U/ml insulin in their venous blood. In their newborns with a normal birth-weight (mean: 3.585 kg, all < 4.000 kg) the insulin levels were not increased either in the umbilical vein (7.0±1.0 U/ml) or in the artery (7.9±1.0 U/ml). The plasma glucose levels in the mothers were 128.0±7.7 mg/100 ml, and in the umbilical vein 105.0±7.5 mg/ 100 ml and in the umbilical artery 88.8±8.6 mg/100 ml. The plasma glucose levels were significantly different from each other. — In six infants with large birthweight (> 4.100 kg) born to untreated mothers with gestational diabetes the insulin levels were superior to the values found in normal newborns. In three of these infants, born to mothers who did not receive a glucose infusion, the insulin levels in the umbilical vein were 38, 42 and 13 U/ml, and in the artery they were 17, 34.5 and 18.5 U/ml. The other three mothers received a glucose infusion, their newborns had in the umbilical vein an insulin level of 15.5, 65 and 19 U/ml and in the artery 20, 72.5 and 14 U/ml. — In conclusion, the normal infant at birth has a low insulin level, which is equal in the umbilical vein and artery. In 6 heavy infants born to untreated latent diabetic mothers, the insulin levels were significantly higher than in normals, and the levels in the umbilical vein and the artery were different from one another. This latter data on hyperinsulinism is discussed in relation with hyperplasia of the islets of Langerhans observed in stillborn infants of mothers with insulin-dependant diabetes or gestational diabetes.Aspirant du Fonds National de la Recherche Scientifique     

Ca overload and the action of calcium sensitive proteases,phospholipases and prostaglandin E2 in myocardial cell degradation

Summary The mechanism of Ca overload-induced myocardial cell injury under hypoxia was examined for the involvement of calcium-activated neutral proteases (CANP), calcium-dependent phospholipases (CDP) or prostaglandins with measuring⁴⁵Ca entry, intake of biologically inert dye, nigrosin, into the cultured myocytes, as was useful for the quantification of sarcolemma permeability, and the release of creatine phosphokinase (CPK) to the culture medium. A Ca channel blocker, verapamil (1 and 10 g/ml) or a Ca ionophore, A 23187 (0.5 to 4 g/ml) dose-dependently decreased or increased both the Ca entry and nigrosin intake in accordance with the CPK release. Furthermore, the inhibitors against CANP, NCO-700 (2 and 20 g/ml) that was demonstrated to permeate sarcolemma using¹⁴C-labelled reagent, against CDP, mepacrine (1 and 10 g/ml) or against cyclooxygenase, indomethacin (1 and 10 g/ml) caused no effect on the Ca entry, nigrosin intake nor CPK release under hypoxia. These results suggest that the Ca overdose into the myocardial cells potentiates their injury and it is not primarily related to the activation of CANP, CDP nor cyclooxygenase.A part of the present study was financially supported by the Ministry of Education, Culture and Science, the Ministry of Health and Welfare, and the Japanese Heart Foundation.