Influence of single nucleotide polymorphisms on thrombin generation in factor V Leiden heterozygotes.

Carriership of the factor V (FV) Leiden mutation increases the risk of venous thromboembolism (VTE) ~4-fold, but the individual risk of each FV Leiden carrier depends on several co-inherited risk and protective factors. Under the hypothesis that thrombin generation might serve as an intermediate phenotype to identify genetic modulators of VTE risk, we enrolled 188 FV Leiden heterozygotes (11 with VTE) and determined the following parameters: thrombin generation in the absence and presence of activated protein C (APC); plasma levels of prothrombin, factor X, antithrombin, protein S and tissue factor pathway inhibitor; and the genotypes of 24 SNPs located in the genes encoding these coagulation factors and inhibitors. Multiple regression analysis was subsequently applied to identify the (genetic) determinants of thrombin generation. The endogenous thrombin potential (ETP) showed a striking inter-individual variability among different FV Leiden carriers and, especially when measured in the presence of APC, correlated with VTE risk. Several SNPs in the F2 (rs1799963, rs3136516), F10 (rs693335), SERPINC1 (rs2227589), PROS1 (Heerlen polymorphism) and TFPI (rs5940) genes significantly affected the ETP-APC and/or the ETP+APC in FV Leiden carriers. Most of these SNPs have shown an association with VTE risk in conventional epidemiological studies, suggesting that the genetic dissection of thrombin generation leads to the detection of clinically relevant SNPs. In conclusion, we have identified several SNPs that modulate thrombin generation in FV Leiden heterozygotes. These SNPs may help explain the large variability in VTE risk observed among different FV Leiden carriers.

Genetic modulation of the FV(Leiden)/normal FV ratio and risk of venous thrombosis in factor V Leiden heterozygotes.

BACKGROUND AND OBJECTIVES: The factor (F)V Leiden mutation causes activated protein C (APC) resistance by decreasing the susceptibility of FVa to APC-mediated inactivation and by impairing the APC-cofactor activity of FV in FVIIIa inactivation. However, APC resistance and the risk of venous thromboembolism (VTE) vary widely among FV Leiden heterozygotes. Common F5 genetic variation probably contributes to this variability. PATIENTS/METHODS: APC resistance was determined in 250 FV Leiden heterozygotes and 133 normal relatives using the prothrombinase-based assay, which specifically measures the susceptibility of plasma FVa to APC. The effects of 12 F5 single-nucleotide polymorphisms (SNPs) on the normalized APC sensitivity ratio (nAPCsr) and on FV levels were determined by multiple regression analysis. RESULTS: In FV Leiden heterozygotes,VTE risk increased with increasing nAPCsr, reaching an odds ratio (OR) of 9.9 (95% confidence interval [CI] 1.2­80.5) in the highest nAPCsr quartile. The minor alleles of several F5 SNPs, including 327 A/G (Q51Q), 409 G/C (D79H), 2663 A/G(K830R, T2 haplotype), 6533 T/C (M2120T) and 6755 A/G (D2194G, R2 haplotype), increased the nAPCsr in FV Leiden heterozygotes, but not in their normal relatives. Most of these effects could be attributed to a shift in the FV(Leiden)/normal FV ratio. Four FV Leiden heterozygotes with extremely high nAPCsr turned out to be pseudo-homozygotes, i.e. they carried a deleterious mutation on the non-Leiden allele. CONCLUSIONS: In FV Leiden heterozygotes, the prothrombinase-based nAPCsr is a marker of VTE risk and is modulated by common F5 SNPs that affect the FV(Leiden)/normal FV ratio in plasma.

Dopamine-sodium relationship in type 2 diabetic patients.

Diabetes mellitus is known to be associated with sodium retention. The aim of the present paper was to investigate the possible role of the renal dopaminergic system in the disturbed sodium homeostasis of Type 2 diabetic patients. The urinary dopamine excretion, which represents the local kidney production, was lower in Type 2 diabetic patients as compared to controls and decreased in insulin treated patients as compared to patients treated without insulin. Urinary dopamine excretion correlated positively with sodium excretion in non-insulin treated patients and in controls, but not in insulin treated patients. In contrast to findings in healthy volunteers, an intravenous sodium load failed to increase the dopamine excretion in Type 2 diabetic patients, despite similar increments in sodium excretion. A low-dose dopamine infusion caused significantly lower natriuretic responses in insulin treated Type 2 diabetic patients as compared to controls, but not in non-insulin treated patients. These findings suggest that Type 2 diabetic patients display a derangement of the renal dopaminergic system, which is accentuated by insulin treatment.

Decreased urinary dopamine excretion and disturbed dopamine/sodium relationship in type 1 diabetes mellitus.

In Type 1 diabetes an increased total body sodium and an impaired ability to excrete a sodium load have been described. A possible involvement of the renal dopaminergic system in this abnormal sodium handling was evaluated through measurements of the urinary output of dopamine, sodium, the dopamine/sodium correlation, and through examining the effect of a dopamine infusion on urinary sodium excretion. Twenty-four hour urinary dopamine excretion was significantly lower in Type 1 diabetic patients as compared to normal controls. A significant correlation between urinary dopamine and sodium excretion was present in normoalbuminuric Type 1 diabetic patients and in normal controls. However, no such correlation could be found in microalbuminuric patients. The increase in fractional excretion of sodium during a 1 h low-dose dopamine (3 micrograms kg-1 min-1) infusion in Type 1 diabetic patients was negatively correlated with diabetes duration. Patients with short duration of diabetes (less than 15 years) had a comparable dopamine-induced increase in fractional excretion of sodium as normal controls. However, patients with longer duration of diabetes (more than 15 years) and microalbuminuric patients displayed no significant changes in sodium output during dopamine infusion. These findings suggest that in Type 1 diabetes mellitus a deficiency of renal dopamine production could be responsible for the impaired sodium handling. Longer duration of the disease and microalbuminuria seem to be associated with an uncoupling of the urinary dopamine/sodium relationship.

Early complications of radioiodine treatment for hyperthyroidism.

Three patients were described with undesirable early complications of low dose radioiodine treatment for hyperthyroidism. The first patient with Graves' disease developed an extreme and permanent hypothyroidism within only few months after receiving this therapy. The second patient with a hyperactive nodular goiter and mild hyperthyroidism had an immediate important exacerbation of the symptoms of hyperthyroidism shortly after a low dose treatment. In the third patient with Graves' disease but without preexisting eye disease a therapy-resistant endocrine ophthalmopathy occurred two months after radioiodine administration.

A multicentre trial of the aldose-reductase inhibitor tolrestat, in patients with symptomatic diabetic peripheral neuropathy. North European Tolrestat Study Group.

One hundred and ninety patients with symptomatic diabetic peripheral neuropathy took part in a double blind multicentre trial of either placebo or tolrestat 200 mg once daily for 6 months. Painful and paraesthetic symptoms, vibration sensory threshold, and nerve conduction velocity (NCV) were assessed as efficacy end-points during the trial. There was an equally marked improvement of painful symptoms during the trial in the tolrestat and placebo groups. A difference in the improvement of paraesthetic symptoms was found however in favour of the placebo group at 24 weeks (p less than 0.02). The deterioration in mean vibration threshold of the tolrestat group was less than placebo at 24 weeks at all 3 sites measured, and reached significance at the carpal site (p less than 0.05). Significant improvements in median motor NCV and in the mean NCV of the four motor nerves were also seen in tolrestat treated patients at 24 weeks compared to placebo (p less than 0.05). In addition, significant changes in favour of tolrestat were seen when the number of motor nerves per patient with NCV increased during the trial was analysed (p less than 0.001). Concordance analysis of patients with increased mean motor NCV and improvement in painful symptoms demonstrated a positive effect for tolrestat compared to placebo (p less than 0.02). Mild reversible elevations of hepatic transaminases were seen in a few patients treated with tolrestat, with no other significant adverse effects. Tolrestat may therefore be helpful in diabetic peripheral neuropathy, where there is little opportunity for therapeutic intervention apart from effort to achieve normoglycaemic control.

Blood glycogen and metabolic control in diabetes mellitus.

The relationship between metabolic control and leukocyte glycogen content in diabetes mellitus was re-evaluated, blood glycogen being measured by an enzymatic procedure. In 30 healthy subjects, fasting blood glycogen averaged 50.6 +/- 2.8 mg l-1 or 7.45 +/- 0.42 ng 10(3)-cells-1, the latter value being unaffected during a 60-min period of induced hyperglycaemia. Comparable levels were found in 18 Type 1 insulin-treated diabetic patients (blood glycogen 50.4 +/- 4.6 mg l-1, leukocyte glycogen 6.92 +/- 0.50 ng 10(3)-cells-1), 6 insulin-treated diabetic patients presenting with chronic pancreatitis (blood glycogen 62.2 +/- 9.3 mg l-1, leukocyte glycogen 6.69 +/- 0.70 ng 10(3)-cells-1) and 12 Type 2 insulin-treated patients (blood glycogen 53.7 +/- 4.3 mg l-1, leukocyte glycogen 7.51 +/- 0.44 ng 10(3)-cells-1). In severely ketotic patients, leukocyte counts and blood glycogen (160.8 +/- 29.6 mg l-1, p less than 0.01 vs stable diabetic patients) were increased, but the leukocytic glycogen content was not significantly affected either before or during intensive insulin therapy and rehydration. The leukocyte glycogen content was abnormally low, however, in 9 untreated Type 2 diabetic patients (5.29 +/- 0.39 ng 10(3)-cells-1, p less than 0.02 vs healthy subjects) and abnormally high (10.77 +/- 0.65 ng 10(3)-cells-1, p less than 0.005 vs healthy individuals) in 30 Type 2 patients treated by sulphonylurea, alone or in combination with insulin. No correlation was found between leukocyte glycogen and either fasting plasma glucose or HbA1c.(ABSTRACT TRUNCATED AT 250 WORDS)

The straight back syndrome.

Chest wall deformities may produce signs that closely mimic organic heart disease. In this category, the straight back syndrome is well recognized. Although clinical identification of this syndrome is thought sufficient to withdraw from any further investigation, its association with idiopathic mitral valve prolapse--a cardiac lesion with considerable morbidity and mortality--may be underestimated. The literature on straight back syndrome is reviewed and its association with mitral valve prolapse discussed.

Effect of rioprostil, a methylprostaglandin E1 analog, on basal and stimulated plasma pancreatic hormone levels in man.

The effect of rioprostil, a methylprostaglandin E1 analog on circulating pancreatic hormones was evaluated in 13 healthy male subjects. Rioprostil administration, 300 micrograms twice daily resulted in a significant decrease of fasting insulin, C-peptide, glucagon, and pancreatic polypeptide. No change in fasting plasma glucose or somatostatin levels was observed. An oral glucose tolerance test induced similar increments in plasma glucose concentration before and during treatment, but a delayed rise of insulin and C-peptide levels occurred during the administration of the drug. On rioprostil, the glucose load no longer inhibited peripheral glucagon or somatostatin. Treatment with rioprostil remained without effect on mixed meal-induced changes in plasma glucose levels and concomitant increases in insulin, pancreatic polypeptide, and somatostatin levels. It is concluded that in healthy individuals rioprostil influences the basal and glucose-induced levels of glucagon, insulin, and somatostatin. In healthy men this effect did not, however, result in glucose intolerance.

Cell surface antibodies in type 1 (insulin-dependent) diabetic patients. II. Presence of immunoglobulins M which bind to lymphocytes.

A standardized cell surface antibody assay was used to measure binding of circulating human immunoglobulins to rat or piglet splenocytes. In 100-fold diluted serum fractions, lymphocyte surface antibodies were detected in 30% of Type 1 (insulin-dependent) diabetic patients under 20 years of age but in none of 33 control subjects. Binding occurred with T and B lymphocytes, appeared unrelated to Fc receptors or protein glycosylation and was not attributable to insulin or albumin antibodies. At clinical onset of the disease, the lymphocyte surface antibodies belonged primarily to the IgM-class. Their presence was positively correlated to that of IgM-pituitary cell surface antibodies and their absorption by anterior pituitary cells occurred as well as by splenocytes. Lymphocyte surface antibodies remained present during the first years of insulin treatment. They were also detected in first degree relatives of lymphocyte surface antibody-positive patients. It is unlikely that IgM-lymphocyte surface antibodies mark the destructive process in the pancreatic B cell population. They may, instead, express a state of immune reactivity which precedes the formation of IgG-autoantibodies and therefore be associated with an event in the development of diseases such as Type 1 (insulin-dependent) diabetes.

Cell surface antibodies in type 1 (insulin-dependent) diabetic patients. I. Presence of immunoglobulins M which bind to rat pituitary cells.

A standardized method has been developed for the assay of cell surface antibodies in IgM- and IgG-fractions from human serum. Suspensions of adult rat islet B cells, islet non-B cells, and anterior pituitary cells were used as antigen source and a cell sorter as analyser of the immunoglobulin binding to individual cells. Assay conditions were selected wherein no surface antibodies were detected in 33 control subjects younger than 20 years. In 30% of Type 1 (insulin-dependent) diabetic patients, surface antibodies were measured with rat anterior pituitary cells as well as with rat islet B cells. Binding to pituitary cells occurred with IgM- and IgG-fractions and correlated positively with IgG binding to islet B cells. At onset of the disease, the prevalence of IgM-rat anterior pituitary cell surface antibodies was higher than that of IgG-rat anterior pituitary cell surface antibodies. Cell surface antibodies were also detected in first-degree relatives of Type 1 diabetic patients, but corresponded primarily to IgM-rat anterior pituitary cell surface antibodies. It is concluded that the development of Type 1 diabetes in subjects younger than 20 years is associated with the generation of both IgM and IgG cell surface antibodies. The IgM surface antibodies may result from stimulated production of polyreactive natural autoantibodies and could precede the switch to the formation of monoreactive IgG autoantibodies. The assay of IgM cell surface antibodies can be useful in studies on the sequence of immune events in diabetes and other autoimmune disease.

Electron microscopic detection of Whipple's bacillus in sarcoidlike periodic acid-Schiff-negative granulomas.

We describe a patient with Whipple's disease without apparent intestinal involvement at initial presentation. Electron microscopy demonstrated the typical bacilli in PAS-negative lymph node and muscle biopsy specimens.

Basal and tolbutamide-induced plasma somatostatin in healthy subjects and in patients with diabetes and impaired glucose tolerance.

Peripheral levels of basal and tolbutamide-induced somatostatin have been measured in patients with diabetes or impaired glucose tolerance (IGT) and compared with those in normal individuals. Basal somatostatin was significantly higher in patients with Type 1 diabetes than in age-matched control subjects. This increase was most pronounced at diagnosis, and appeared to be related to metabolic control in insulin-treated patients. No increase was noted in patients with Type 2 diabetes or with IGT. Intravenous bolus injection of tolbutamide enhanced peripheral somatostatin levels in healthy volunteers in a biphasic manner. Patients with IGT also exhibited a biphasic response but the amplitude of the first phase was higher. No secretory response was detected in 27/29 Type 1 diabetic patients at diagnosis; a somatostatin response to tolbutamide became detectable again in Type 1 patients with normalization of their basal somatostatin levels but was then paradoxically related to poor blood glucose control. In Type 2 diabetes, basal somatostatin levels were similar to age-matched control subjects, but decreased upon intravenous tolbutamide administration.

Iodine-123 MIBG imaging in a generalized pancreatic polypeptide-gastrin-serotonin secreting tumor.

The usefulness of radio-metaiodobenzylguanidine (MIBG), a specific radiopharmaceutical agent for scintigraphic imaging and treatment of phaeochromocytoma and neuroblastoma, has been extended to the location of carcinoid tumors. Scintigraphic evaluation with I-123 MIBG in a patient with a histologically proven endocrine tumor (apudoma) of unknown origin with liver and bone metastases is reported. Elevated plasma hormone levels of gastrin, pancreatic polypeptide, and serotonin were found. Tumoral content of these hormones was immunocytochemically confirmed on liver biopsy. I-123 MIBG uptake could be seen in those areas of the liver with deficient lesions in the Tc-99m colloid image with a maximal uptake in a large mass at the level of the left liver lobe. No abnormal uptake could be observed at any other level, which was in contrast with autopsy findings of generalized metastatic disease.

Bromism after prolonged use of carbromal.

Most of the brominated monoureide and bromide salt containing drugs are obtainable in Belgium without prescription. Apart from the regularly encountered suicidal attempts, these drugs can also, without the intention of the patient, cause bromism . We report two cases of patients recently admitted because of bromism after prolonged use of Carbromal . Bromism now has become a rather unfamiliar condition. Therefore diagnostic and therapeutic aspects are briefly discussed. Because we dispose now, for the same indications, of more efficient and much less toxic drugs, we suggest that drugs containing a significant amount of brominated monoureides or bromide salts should be removed from the market.