Follow-up of women with previous GDM. Insulin, C-peptide, and proinsulin responses to oral glucose load

Gestational diabetes mellitus (GDM) is a strong predictor of glucose intolerance later in life. Former GDM (n = 145) and control (n = 41) subjects were studied 3-4 yr after the index pregnancy. They were subjected to a 75-g oral glucose tolerance test (OGTT) with measurements of insulin, C-peptide, and proinsulin in the basal state and every 30 min for 180 min. In the former GDM group, 5 subjects (3.4%) had developed non-insulin-dependent diabetes mellitus (NIDDM), and 32 (22%) had developed impaired glucose tolerance (IGT; by World Health Organization criteria). In the control group, 2 (4%) had IGT. In the GDM group, IGT or NIDDM was significantly associated with obesity (body mass index [BMI] greater than or equal to 25 kg/m2) and earlier diagnosis of GDM during pregnancy (P less than 0.001). Nonobese (BMI less than 25 kg/m2) GDM subjects with normal glucose tolerance at follow-up had significantly higher mean glucose (P less than 0.01), insulin (P less than 0.05), and proinsulin (P less than 0.001) values during the OGTT than control subjects, whereas there was no significant difference in C-peptide values. A comparison between control subjects with normal OGTT and BMI less than 25 kg/m2 (n = 39) and GDM subjects (n = 39) selected to have a comparable area under the glucose curve, BMI, and age demonstrated no group differences in glucose, C-peptide, or insulin levels, whereas the proinsulin levels were significantly higher (P less than 0.001) during the glucose load. The molar ratio between proinsulin and insulin was also significantly higher among the former GDM subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Real-time biospecific interaction analysis using surface plasmon resonance and a sensor chip technology

We report here the development and application of a biosensor-based technology that employs surface plasmon resonance for label-free studies of molecular interactions in real time. The sensor chip interface, comprising a thin layer of gold deposited on a glass support, is derivatized with a flexible hydrophilic polymer to facilitate the attachment of specific ligands to the surface and to increase the dynamic range for surface concentration measurements. The sensor can be used to measure surface concentrations down to 10 pg/mm2. Typical coefficients of variation are from two to five percent. We anticipate that the ability to monitor multi-molecular complexes as they form will greatly contribute to the understanding of biorecognition and the structural basis of molecular function.

Antihypertensive effects of chronic 5-hydroxytryptamine (5-HT2) receptor blockade with irindalone in the spontaneously hypertensive rat

The present study was conducted to evaluate the antihypertensive effects of irindalone, a potent 5-HT2-receptor blocking agent with weak alpha 1-adrenoceptorblocking properties. Young spontaneously hypertensive rats (SHR) received irindalone in the food (daily intake estimated to 10 mg/kg) for 10 weeks and older SHR received irindalone subcutaneously for 2 weeks (3 mg/kg/day by osmotic pump). The indirect systolic blood pressure was measured each week (tail plethysmography) and at the end of the intervention periods the direct intraarterial blood pressure was measured in conscious rats. Subsequently a dose-response curve of pressor responses to phenylephrine was constructed in pithed rats. Chronic oral treatment with irindalone reduced the development of hypertension but influenced neither body weight nor heart weight. The subcutaneous treatment with irindalone reduced the blood pressure in relatively older SHR compared with controls. Pressor responses to phenylephrine were antagonized in rats receiving oral treatment. However, during subcutaneous treatment with irindalone the dose-response curve to phenylephrine was not influenced, suggesting that the blood pressure reduction was not directly related to a concomitant alpha 1-adrenoceptor blockade. These results demonstrate that irindalone effectively reduces the blood pressure in SHR and that no tolerance develops to its antihypertensive effects. Since the blood pressure reduction, at least following subcutaneous treatment, was not directly related to a concomitant alpha 1-blockade, it is suggested that the 5-HT2-receptor blockade may be of relevance for the antihypertensive effect.

Characteristics of short-chain alcohol dehydrogenases and related enzymes

Different short-chain dehydrogenases are distantly related, constituting a protein family now known from at least 20 separate enzymes characterized, but with extensive differences, especially in the C-terminal third of their sequences. Many of the first known members were prokaryotic, but recent additions include mammalian enzymes from placenta, liver and other tissues, including 15-hydroxyprostaglandin, 17 beta-hydroxysteroid and 11 beta-hydroxysteroid dehydrogenases. In addition, species variants, isozyme-like multiplicities and mutants have been reported for several of the structures. Alignments of the different enzymes reveal large homologous parts, with clustered similarities indicating regions of special functional/structural importance. Several of these derive from relationships within a common type of coenzyme-binding domain, but central-chain patterns of similarity go beyond this domain. Total residue identities between enzyme pairs are typically around 25%, but single forms deviate more or less (14-58%). Only six of the 250-odd residues are strictly conserved and seven more are conserved in all but single cases. Over one third of the conserved residues are glycine, showing the importance of conformational and spatial restrictions. Secondary structure predictions, residue distributions and hydrophilicity profiles outline a common, N-terminal coenzyme-binding domain similar to that of other dehydrogenases, and a C-terminal domain with unique segments and presumably individual functions in each case. Strictly conserved residues of possible functional interest are limited, essentially only three polar residues. Asp64, Tyr152 and Lys156 (in the numbering of Drosophila alcohol dehydrogenase), but no histidine or cysteine residue like in the completely different, classical medium-chain alcohol dehydrogenase family. Asp64 is in the suggested coenzyme-binding domain, whereas Tyr152 and Lys156 are close to the center of the protein chain, at a putative inter-domain, active-site segment. Consequently, the overall comparisons suggest the possibility of related mechanisms and domain properties for different members of the short-chain family.

Lipoprotein lipases and vitellogenins in relation to the known three-dimensional structure of pancreatic lipase

A 106-residue region of high similarity between lipoprotein/pancreatic/hepatic lipases and Drosophila vitellogenins encompasses four beta-strands with all residues but one strictly conserved or conservatively replaced between the structures, and enclosing the putative active site Ser-152. The properties suggest a common folding pattern but the region probably does not function as an 'interface recognition site' in the lipases, although it might well bind fatty acid esters of ecdysteroids or single lipid molecules in the vitellogenins. C-terminally of this 106-residue region, a surface loop ('flap') covers the active site. No residue within this loop is conserved through all lipases, but adjacent segments exhibit 60-70% residue identity. Hepatic and lipoprotein lipases probably hydrolyze both soluble and emulsified substrates at the same site. They lack residues corresponding to a second active site postulated in pancreatic lipase to account for hydrolysis of soluble substrates. In addition, due to structural differences the flap could prevent entry of soluble substrate molecules into the active site of pancreatic lipase.

Renal functional effects of prostaglandin synthesis inhibition in patients with insulin-dependent diabetes mellitus of long duration without nephropathy

The short-term effects of prostaglandin synthesis inhibition (PGSI; single dose 500 mg of naproxen) on renal function were studied in six women (age: 21.9 +/- 2.4 yrs) with insulin dependent diabetes mellitus (IDDM) of 14.3 +/- 2.8 yrs' duration, and in nine age- and sex-matched controls. The diabetics had no overt signs of nephropathy (Albustix neg, normal serum creatinine, and blood pressure). The clearance of inulin (CIn) and PAH; the filtration fraction (FF); and the excretion of Na, albumin and PGE2 were studied under water diuresis on two separate mornings, first without and then with PGSI. With PGSI all individuals has lower PGE2 excretion. The CIn and FF were significantly (p less than 0.05) higher in the diabetics than in the controls both without (129.4 +/- 23.9 ml/min/1.73 m 2 and 23.4 +/- 2.8% vs. 107.6 +/- 10.3 and 19.7 +/- 1.6) and with (133.7 +/- 29.4 and 22.6 +/- 2.1, vs. 106.8 +/- 10.3 and 20.1 +/- 1.5) PGSI. The diuresis and Na excretion were significantly lower with PGSI, than without, in both groups. The albumin excretion was significantly higher in the diabetics under both conditions (29.9 +/- 16.6 and 34.2 +/- 19.9 micrograms/min/100 ml GFR, vs. 14.5 +/- 10.6 and 12.9 +/- 8.3 in controls). We conclude that the hyperfiltration in this stage of IDDM does not appear to be PG dependent, and that PGSI does not give any immediate effects on the albumin excretion.

A simplified model for management of women with gestational diabetes at the primary care level

A simplified model for management of women with gestational diabetes mellitus (GDM) that could be applied at the level of the primary antenatal care was evaluated. Two groups were compared: group I included 172 consecutive GDM subjects cared for at the hospital-based specialized antenatal clinic 1984-85. Group II included 149 consecutive GDM subjects cared for at the primary antenatal clinics 1985-86. Both groups were instructed in self-monitoring of blood glucose and were given dietary instructions. Insulin treatment was initiated if blood-glucose exceeded 9 mmol/l post-prandially three times a week. While women in group II mainly were cared for by midwives, following the routine antenatal program, women in group I were seen every two weeks by an obstetrician and non-stress tests were performed twice weekly from gestational week 35. There were no significant differences with respect to the number of women who required insulin treatment, rate of pregnancy complications or mode of delivery. There were two intrauterine deaths, one in each group, both were unrelated to GDM. There were no group differences regarding large-for-gestational-age infants, respiratory disturbances, neonatal hypoglycemia, hyperbilirubinemia or polycythemia. We conclude that an effective care of GDM-women can be achieved at the primary care level provided frequent self-monitoring of blood glucose is performed for early detection of insulin requiring diabetes.

The gene from the short arm of chromosome 3, at D3F15S2, frequently deleted in renal cell carcinoma, encodes acylpeptide hydrolase

Loss or inactivation of a gene on the short arm of chromosome 3 may contribute to the genesis of renal cell carcinoma. A gene that corresponds to the most frequently lost RFLP site (D3F15S2) is expressed in a variety of human tissues, and at a particularly high level in the kidney. Its expression is markedly reduced in renal cell carcinoma. A database search showed that the gene product is closely related to or identical with acylpeptide hydrolase. The nucleotide identity between the rat acylpeptide hydrolase and the human gene at D3F15S2 is 88%, compatible with normal species differences. It is therefore likely that the human gene product is acylpeptide hydrolase. The renal cell carcinoma is then associated with a decrease of acylpeptide hydrolase activity. The gene may represent a tumor suppressor gene, whose loss contributes to the development of renal cell carcinoma. It might be speculated that it could act e.g. by affecting the activity of a small acetylated growth factor. Alternatively, its decreased expression may merely reflect the impairment of differentiation in RCC, compared to normal kidney. Loss of a linked but irrelevant gene by the 3p deletion is another possibility.

Flow-force relationships during energy transfer between mitochondrial proton pumps

The effect of inhibitors of proton pumps, of uncouplers and of permeant ions on the relationship between input force, delta mu H+, and output flows of the ATPase, redox and transhydrogenase H(+)-pumps in submitochondrial particles was investigated. It is concluded that: (1) The decrease of output flow of the transhydrogenase proton pump, defined as the rate of reduction of NADP+ by NADH, is linearily correlated with the decrease of input force, delta mu H+, in an extended range of delta mu H+, independently of whether the H(+)-generating pump is the ATPase or a redox pump, or whether delta mu H+ is depressed by inhibitors of the H(+)-generating pump such as oligomycin or malonate, or by uncouplers. (2) The output flows of the ATPase and of the site I redox H(+)-pumps exhibit a steep dependence on delta mu H+. The flow-force relationships differ depending on whether the depression of delta mu H+ is induced by inhibitors of the H(+)-generating pump, by uncouplers or by lipophilic anions. (3) With the ATPase as H(+)-consuming pump, at equivalent delta mu H+ values, the output flow is more markedly inhibited by malonate than by uncouplers; the latter, however, are more inhibitory than lipophilic anions such as ClO4-. With redox site I as proton-consuming pump, at equivalent delta mu H+ values, the output flow is more markedly inhibited by oligomycin than by uncouplers; again, uncouplers are more inhibitory than ClO4-. (4) The results provide further support for a delocalized interaction of transhydrogenase with other H(+)-pumps.

Functionally important regions of glucose-6-phosphate dehydrogenase defined by the Saccharomyces cerevisiae enzyme and its differences from the mammalian and insect forms

The primary structure of Saccharomyces cerevisiae glucose-6-phosphate dehydrogenase has been determined. It consists of 503 amino acid residues, with an acetyl-blocked N-terminus. The structure shows equally extensive differences from the corresponding mammalian and fruit fly enzymes (52% residues non-identical). Residues conserved in all the forms constitute about 40% of the structures and include two histidines. One of these (His200 in the numbering of the rat enzyme) occurs in a 10-residue conserved segment, including the reactive Lys204, probably related to substrate binding. Two segments with conserved Gly-Xaa-Xaa-Gly-Xaa-Xaa-Gly/Ala pattern constitute possibilities for the coenzyme-binding site. One is N-terminally located (positions 37-43) with two conserved arginine residues nearby (positions 56 and 71), of interest for phosphate binding. The other (positions 241-247) is in a middle region, with many residue identities, containing the conserved residues Arg256 and His264.

Different segment similarities in long-chain dehydrogenases

Long-chain dehydrogenases were scrutinized for common patterns. Overall molecular similarities are not discerned, in contrast to the situation for several short-chain and medium-chain dehydrogenases, but coenzyme-binding segments are discernible. Species variants of glucose-6-phosphate dehydrogenase reveal about 20% strictly conserved residues, grouped into three segments and supporting assignments of sites for coenzyme-binding and catalysis. Glycine is overrepresented among the residues conserved, typical of distantly related proteins. Two of the enzymes within the pentose phosphate pathway reveal a distant similarity of interest for further evaluation, between a C-terminal 178-residue segment of glucose-6-phosphate dehydrogenase and the N-terminal part of 6-phosphogluconate dehydrogenase.

Urinary C-peptide excretion in obese and anorectic children

To assess the total insulin secretion in children in different nutritional states we have analysed the 24 h urinary C-peptide excretion in 32 obese children (16 boys and 16 girls) 8-15 years of age as well as in 7 girls with anorexia nervosa 11-16 years of age. Obese children had a median urinary C-peptide excretion rate of 0.27 nmol/kg/24 h, which was not different from that of a group of normal-weight children. In the group of anorectic girls, on the other hand, the median value 0.47 nmol/kg/24 h was significantly (p less than 0.05) higher than for normal-weight girls of the same age (median = 0.26 nmol/kg/24 h). These results indicate that in obese children insulin secretion, measured as the 24 h urinary C-peptide excretion per kg body weight, is the same as in normal-weight children. Total insulin secretion is consequently increased. In anorexia nervosa, on the other hand, the higher C-peptide excretion per kg body weight compared with normal-weight children, indicates that insulin secretion is increased in relation to body weight.

Clinical pharmacokinetics of ketanserin

Ketanserin is a serotonin S2-receptor antagonist introduced for the treatment of arterial hypertension and vasospastic disorders. Plasma concentrations of ketanserin (and some metabolites) can be measured with high performance liquid chromatography using ultraviolet or fluorescence detection, or by radioimmunoassay. The methods are sensitive, accurate and specific. Following oral administration ketanserin is almost completely (more than 98%) and rapidly absorbed and peak concentrations in plasma are reached within 0.5 to 2 hours. It is subject to considerable extraction and metabolism in the liver (first-pass effect) and the absolute bioavailability is around 50%. The compound is extensively distributed to tissues and the volume of distribution is in the order of 3 to 6 L/kg. In plasma ketanserin binds avidly to plasma proteins, mainly albumin, and the free fraction is around 5%. Ketanserin is extensively metabolised and less than 2% is excreted as the parent compound. The major metabolic pathway is by ketone reduction leading to formation of ketanserin-ol which is mainly excreted in the urine. Ketanserin-ol, which by itself does not contribute to the overall pharmacological effect, is partly reoxidised into ketanserin, and it is likely that the terminal half-life of the parent compound is related to the slow ketanserin regeneration from the metabolite. Following intravenous administration plasma ketanserin concentrations decay triexponentially with sequential half-lives of 0.13, 2 and 14.3 h. The terminal half-life is similar after oral administration. Following long term oral dosing (20 or 40 mg twice daily) the pharmacokinetics remain linear and steady-state concentrations, which can be predicted from single-dose kinetics, are reached within 4 days. During long term treatment with the common dosage of 40 mg twice daily, steady-state concentrations fluctuate between 40 micrograms/L (trough) and 100 to 140 micrograms/L (peak). The pharmacokinetic properties of ketanserin are predictable in a wide group of patients and there is no influence from the duration of treatment, age and sex of the patient or concomitant treatment with beta-blockers or diuretics. There is no direct relationship between plasma concentrations of ketanserin and the antihypertensive effect in a group of patients. Side effects, including prolongation of the Q-T interval, are dose-dependent and, at least in the individual patient, related to peak plasma concentrations. In separate studies the pharmacokinetics of ketanserin were investigated in special patient groups, namely the elderly and patients with hepatic and renal insufficiency.(ABSTRACT TRUNCATED AT 400 WORDS)

Indications that branched chain amino acids, in addition to glucagon, affect the glomerular filtration rate after a high protein diet in insulin-dependent diabetes

Hormonal changes and whole blood free amino acid levels and their relation to renal function were measured in 12 insulin-dependent diabetic patients after two 10-day periods with a diet consisting of 10% and 20% respectively of the energy as protein. The patients were 15-21 years old and mean duration of diabetes was 12 (5-20) years. Glomerular filtration rate, renal plasma flow, and albumin excretion rate were measured together with plasma concentrations of glucagon, growth hormone, insulin-like growth factor 1 (IGF-1), somatostatin, serum insulin and free amino acids in blood. Glomerular filtration rate was 123 +/- 3 ml/min/1.73 m2 on high protein diet and 113 +/- 3 ml/min/1.73 m2 on low protein diet (p = 0.02). Renal plasma flow was unchanged. Glucagon, IGF-1, branch chained amino acids (BCAA), tyrosine, phenylalanine, lysine, and methionine were increased after the high protein diet. Growth hormone, somatostatin, insulin, and other amino acids remained unchanged. The increase in glomerular filtration rate was significantly correlated to the increase in glucagon, isoleucine, and valine (glucagon r = 0.71, p = 0.01, isoleucine r = 0.59, p = 0.04, valine r = 0.62, p = 0.03). In a multiple regression model the increase in glomerular filtration correlated most strongly to the increase in isoleucine, followed by valine and glucagon. Together these variables explained 88% of the total variance of the change in glomerular filtration rate (r2 = 0.88, p = 0.001). Albumin excretion rate was correlated to IGF-1 (r = 0.86, p less than 0.001) on the high protein diet.(ABSTRACT TRUNCATED AT 250 WORDS)

A circular dichroism study of mitochondrial transhydrogenase from beef heart

This paper describes a circular dichroism (CD) spectroscopy study of purified proton-pumping nicotinamide nucleotide transhydrogenase from beef heart. The CD spectrum obtained was used to estimate the content of secondary structures of the purified enzyme and suggests the presence of 40-45% alpha-helical structure and long, possibly membrane-spanning alpha-helices. The spectrum was essentially unaffected by the absence or presence of transhydrogenase substrates, suggesting that the catalytic and proton-translocating activities of the enzyme occur without major rearrangements at the level of secondary structures.

Cytogenetic analysis of 33 basal cell carcinomas

Cytogenetic analysis of short-term cultures from 33 basal cell carcinomas (BCC), a type of neoplasm for which no previous karyological data exist, revealed clonal chromosome aberrations, all of them different, in 8 tumors. In 2 cases, 2 cytogenetically unrelated clones were detected, suggesting a multicellular origin in at least a subset of BCC. A remarkably high level of nonclonal structural rearrangements, mostly in the form of seemingly balanced translocations, was found in 23 tumors; namely, in 6 of 8 BCC with clonal karyotypic abnormalities and in 17 of 25 without. It is possible that some of these aberrations represent additional neoplastic clones, thus indicating an even higher level of cytogenetic heterogeneity in BCC. We think that the most likely interpretation of the results is that BCC may have a multicellular origin, reflecting field cancerization of the skin. During subsequent tumor development, the selection pressure narrows down the number of clones that infiltrate the surrounding tissue. The finding by karyotypic analysis of some apparently monoclonal, some polyclonal BCC, may reflect that different tumors have been examined at different points in the clonal evolution of the neoplastic cells.

Reflexogenic neuronal and humoral responses to selective stimulation of low-pressure cardiopulmonary receptors in man

This study was conducted to determine the relative importance of efferent muscle sympathetic nerve activity (MSA), vasopressin (ADH) and atrial natriuretic peptide (ANP) in the short-term neurohumoral response to moderate changes in low-pressure cardiopulmonary receptor activity. The low-pressure receptors were stimulated and unloaded, respectively, by autotransfusion of blood (450 ml) and the application of lower body negative pressure (LBNP, -20 mmHg), and in 11 healthy men we measured MSA in the left peroneal nerve, indirect blood pressure, ECG, central venous pressure (CVP) and venous plasma concentrations of ANP and ADH (radioimmunoassay). Total MSA rose by 30% during LBNP and decreased during a rapid autotransfusion of blood, and the changes in MSA were significantly related to changes in CVP. The plasma concentrations of ADH and ANP were not significantly affected by either procedure. It is suggested that during moderate short-term changes in venous return, MSA responded more rapidly and/or at a lower threshold than the ADH and ANP systems.

Acute C-peptide, insulin and branched chain amino acid response to feeding in formula and breast fed infants

The response of C-peptide in serum and urine and of glucose and branched chain amino acids in blood to formula and breast feeding was assessed in six breast-fed and six formula-fed infants 3-6 months of age. We analysed serum C-peptide, branched chain amino acids (BCAA) in blood, and blood glucose in the fasting state at 90' and 180' after a regular meal. The excretion of urinary C-peptide and creatinine was also determined. The formula-fed infants received a formula in current use, containing 15-16 g protein/l and with a casein/whey ratio of 40/60. In the fasting state, no significant inter-group difference was found in the level of serum C-peptide or the valine/glycine ratio. Postprandially, the formula-fed infants had significantly higher serum C-peptide values and valine/glycine ratio than the breast-fed infants, p less than 0.05. No significant inter-group difference was found for blood glucose. The urinary C-peptide/creatinine ratio was significantly lower in the breast-fed group, p = 0.02, and significantly correlated both to the valine/glycine ratio at 90', rs = 0.75, p = 0.02 and to the serum C-peptide value at 90', rs = 0.66, p = 0.03. These results confirm that in formula-fed infants the insulin response to a meal is enhanced compared to that in breast-fed infants. The finding of similar blood glucose values in the two groups may also indicate an insulin resistance in the formula-fed infants following a meal.

A fragment of triosephosphate isomerase competes with the vasoactive intestinal polypeptide (VIP) for binding to the VIP receptor

A 28-residue N-terminal fragment of triosephosphate isomerase, TIM(1-28), has been purified from porcine upper intestine. It competes with VIP for binding to the VIP receptor on rat liver plasma membranes with an IC50 value of 2.8 mM, about 1000 times higher than that for VIP binding to the membranes. Except for a single positional identity and the number of amino acid residues, the amino acid sequences of TIM(1-28) and VIP are unrelated as regards primary structure. However, the ability to bind to the same receptor site may indicate common three-dimensional structural properties.

Mortality pattern among pulp and paper mill workers in Sweden: a case-referent study

The mortality pattern among Swedish pulp and paper mill workers was evaluated in a case-referent study encompassing 4,070 men decreased during the period 1950-1987. The subjects were identified from the register of deaths and burials in six parishes. A significantly increased mortality was seen for diabetes mellitus and for secondary tumors of the lung and liver among the pulp and paper mill workers. Indications of excess risks were also found for obstructive lung disorders, pulmonary emboli, accidents, and pneumonia, as well as for malignant lymphomas, leukemias, and cancer of the pancreas and stomach. In the only parish where a sulfite process was exclusively used, cancer of the digestive tract and especially of the rectum was found to be in excess. Except for this parish, the sulfate process predominated in the plants included. The mortality pattern found in this study is in reasonable agreement with findings in various studies from this type of industry.