Two aberrant splicings caused by mutations in the insulin receptor gene in cultured lymphocytes from a patient with Rabson-Mendenhall's syndrome.

Rabson-Mendenhall's syndrome is one of the most severe forms of insulin resistance syndrome. We analyzed an English patient described elsewhere and found novel mutations in both alleles of the insulin receptor gene. One is a substitution of G for A at the 3' splice acceptor site of intron 4, and the other is an eight-base pair deletion in exon 12. Both decrease mRNA expression in a cis-dominant manner, and are predicted to produce severely truncated proteins. Surprisingly, nearly normal insulin receptor levels were expressed in the patient's lymphocytes, although the level of expression assessed by immunoblot was approximately 10% of the control cells. Insulin binding affinity was markedly reduced, but insulin-dependent tyrosine kinase activity was present. Analyzing the insulin receptor mRNA of the patient's lymphocytes by reverse transcription PCR, we discovered aberrant splicing caused by activation of a cryptic splice site in exon 5, resulting in a four-amino acid deletion and one amino acid substitution, but restoring an open reading frame. Skipped exon 5, another aberrant splicing, was found in both the patient and the mother who had the heterozygotic mutation, whereas activation of the cryptic splice site occurred almost exclusively in the patient. Transfectional analysis in COS cells revealed that the mutant receptor produced by cryptic site activation has the same characteristics as those expressed in patient's lymphocytes. We speculate that this mutant receptor may be involved in the relatively long survival of the patient by rescuing otherwise more severe phenotypes resulting from the complete lack of functional insulin receptors.

Cell-mediated immunity in diabetes mellitus; lymphocyte transformation by insulin and insulin fragments in insulin-treated and newly-diagnosed diabetes.

Using a radioisotope labeling technic, the ability of bovine and porcine insulin antigens to induce lymphocyte transformation was tested with cells from the peripheral blood of thirty nondiabetic controls, fifty established insulin-dependent diabetics with no evidence of insulin allergy, and ten newly diagnosed diabetics (five untreated, five insulin-treated for less than three weeks). Lymphocytes from twenty-six (42 per cent) of the diabetics showed significant blastogenesis to bovine or porcine insulin, as compared with two (7 per cent) of controls; the phenomenon was shown by both established and newly diagnosed patients including four who had never recieved insulin. The results indicate that cellular hypersensitivity to insulin, as judged by an in vitro test, is relatively common in insulin-treated diabetics without in vivo evidence of allergy, and suggest that hypersensitivity may also be present in untreated diabetics. Lymphocytes from twenty-one of the twenty-six diabetics who responded to intact insulin were further tested using bovine and porcine insulin A chain bovine B chain as antigens. The A chain of either insulin induced significant blastogenesis in only one diabetic but bovine B chain induced significant blastogenesis in fourteen (67 per cent) of the patients tested. These results suggest that B chain is the major antigenic site determining cellular hypersensitivity to insulin. Diabetes 24:36-43, January, 1975.

Tissue plasminogen activator inhibition in diabetes mellitus.

Depression of fibrinolysis may be relevant to the vascular complications of diabetes mellitus. Plasminogen activator inhibitor (PAI) is an important inhibitor of fibrinolysis in humans, and we have found basal activities of PA inhibition to be elevated in patients with diabetes compared with a reference group of healthy subjects (mean +/- SD 268 +/- 268 vs. 105 +/- 48%; P less than .0001). With a monoclonal antibody, it was shown that high inhibition values were due to PAI-1. No differences in PA inhibition were noted in relation to type of diabetes, diabetic treatment, or presence or absence of vascular complications. Basal PA inhibition did not correlate with in vivo (B beta 15-42 antigen) or ex vivo (fibrin plate) fibrinolytic activity or HbA1. In patients with non-insulin-dependent diabetes mellitus, treatment with the anabolic steroid stanozolol significantly reduced PA inhibition. These findings suggest a further abnormality of fibrinolysis in diabetes, but the lack of a relationship among other measures of fibrinolysis renders its biologic significance uncertain.

Macrosomia in pregnancy complicated by insulin-dependent diabetes mellitus.

We assessed the factors influencing the birth weight of infants born to 83 women with insulin-dependent diabetes mellitus (IDDM) over a 5-yr period. Maternal glycosylated hemoglobin (HbA1) concentrations at delivery correlated with the percentile birth-weight ratios (r = .43, P less than .001) and indicated that approximately 18% of variance in the birth weight could be ascribed to glycemic control in the third trimester. Fetal macrosomia occurred in 22 (27%) pregnancies. When 20 of these pregnancies were compared closely with 20 nonmacrosomic pregnancies in diabetic women, the mothers of macrosomic infants were found to be more obese, have a history of previous macrosomic birth, and have higher concentrations of serum human placental lactogen and urinary estriols in the third trimester. Macrosomic pregnancy was further distinguished by accelerated fetal growth (judged by serial ultrasonography) from the 32nd wk of gestation and by biochemical (but asymptomatic) hypoglycemia in the neonate. In our study, no serious neonatal morbidity could be attributed to macrosomic pregnancy. Good glycemic control was attained in both groups, and no significant differences between the groups in overall glycemic control throughout pregnancy were noted. Thus, despite good glycemic control, macrosomia remains comparatively common in modern pregnancy complicated by IDDM, and factors other than maternal hyperglycemia must contribute to its etiology.

Pruritus in diabetes mellitus: investigation of prevalence and correlation with diabetes control.

Three hundred diabetic and 100 nondiabetic hospital outpatients (both groups of comparable age and sex distribution) were assessed for the presence of generalized and localized pruritus. Pruritus vulvae was significantly more common in diabetic women (18.4%) than in controls (5.6%) and was significantly associated with poor diabetes control (mean glycosylated hemoglobin level less than 12%). Other forms of localized pruritus were equally common in diabetic and nondiabetic patients, regardless of glycosylated hemoglobin levels. Generalized pruritus was present in 14 diabetic patients, but in 5 cases the symptom was ascribed to intercurrent illness or drug administration. Thus, generalized pruritus without apparent cause was present in only 8 diabetic patients (2.7%) and was not significantly more common than in nondiabetic patients. It is doubtful if diabetes mellitus per se should be regarded as a cause of generalized or localized pruritus, other than pruritus vulvae.

A double-blind crossover trial comparing human insulin (recombinant DNA) with animal insulins in the treatment of previously insulin-treated diabetic patients.

Ninety-four diabetic patients established on treatment with pork (N = 47) or beef insulin (N = 47) took part in a double-blind crossover trial in which 6-wk treatment periods of their animal insulin were compared with similar periods on human insulin (recombinant DNA). Six patients withdrew during the trial--in three cases for hypoglycemia while taking human insulin. In patients initially treated with beef insulin there was no significant change in the mean blood glucose, the 'M' index, the total daily insulin dose, or the frequency of hypoglycemic attacks after the change to human insulin. Home blood glucose sample values were greater before the morning and evening insulin injection on human insulin (morning: 12.8 mmol/L [beef] versus 14.2 mmol/L [human insulin] [P less than 0.05]; evening: 10.0 mmol/L versus 11.6 mmol/L [P = 0.05]). In pork insulin-treated patients greater values while on human insulin were found for mean glucose (9.0 mmol/L [pork] versus 9.7 mmol/L [human insulin], P = 0.05), 'M' index (65.0 [pork] versus 79.6 [human insulin], P less than 0.025), and total daily insulin dose (50.9 U/day [pork] versus 52.5 U/day [human insulin], P less than 0.001). The early morning glucose sample was also greater on human insulin (9.6 mmol/L [pork] versus 12.1 mmol/L [human insulin], P less than 0.001). No significant differences in either insulin antibody levels or E. coli protein antibody levels were found between either of the animal-insulin treatment periods and human insulin treatment periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Response of insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) and IGFBP-3 to IGF-I treatment in severe insulin resistance.

It has been suggested that recombinant human IGF-I (rhIGF-I) is a potential therapeutic agent in diabetes mellitus. It is known to have glucose-lowering effects in normal individuals, in patients with non-insulin-dependent diabetes (NIDDM) and in extreme insulin-resistant states. IGF-binding proteins (IGFBPs) have the potential to affect the biological activity of rhIGF-I. We have studied the effect of infused rhIGF-I on IGFBP-1 and IGFBP-3 in a patient with Mendenhall's syndrome, a rare insulin-resistant state. During an infusion of 20 mg rhIGF-I, glucose concentrations fell from 44.1 +/- 7.2 to 31.5 +/- 7.2 (S.E.M.) mmol/l (P = 0.001), and insulin and C-peptide levels fell from 920 +/- 62 to 542 +/- 45 mU/l (P = 0.008) and 5466 +/- 633 to 3071 +/- 297 pmol/l (P = 0.02) respectively. Significant lowering of phosphate, magnesium and alkaline phosphatase concentrations was also noted. IGF-I levels rose from 48 +/- 10.2 to 410 +/- 50.1 micrograms/l (P = 0.001), and those of IGF-II fell from 279.8 +/- 8.3 to 104.3 +/- 7.9 micrograms/l (P = 0.001). IGFBP-1 concentrations did not significantly change during the infusion but those of IGFBP-3 increased from 1655 +/- 127 to 2197 +/- 334 micrograms/l (P = 0.002), despite a significant fall in GH concentrations from 10.7 +/- 2.6 to 4.1 +/- 1.1 mU/l (P = 0.007), suggesting that IGFBP-3 regulation is also IGF-I-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in phagocytic function with glycaemic control in diabetic patients.

Phagocytic function was assessed by serial whole blood chemiluminescence in poorly controlled type 2 (non-insulin dependent) diabetic patients during efforts to improve glycaemic control and compared with a group of well controlled type 1 (insulin dependent) diabetic patients. Chemiluminescence (corrected to a standard polymorphonuclear count) remained below normal (0.15-0.30 photons/second/cell) for most of the type 2 patients until 12 weeks when the value was significantly increased in patients showing improved glycaemic control (mean (range) 0.25 (0.01-0.43) photons/second/cell) compared with those showing no improvement (0.12(0.01-0.31) photons/second/cell). There was a significant inverse correlation of delta HbA1 with delta chemiluminescence. Although mean chemiluminescence for the type 1 diabetic patients was within the normal range, there was a wide scatter of values (0.19 (0.04-0.43) photons/second/cell) and there was no significant difference compared with the final value of type 2 patients with improved control. Glycaemic control is therefore a major determinant of phagocytic function in diabetic patients, but other factors must contribute, particularly in type 1 (insulin dependent) patients.

Circulating cell adhesion molecule concentrations in diabetic women during pregnancy.

OBJECTIVE: To determine whether circulating concentrations of defined cell adhesion molecules, which are thought to reflect endothelial expression, are increased in insulin-dependent diabetic women during pregnancy. METHODS: Pregnant diabetic women demonstrating good glycemic control and without major complications before pregnancy were studied at 8-12 (n = 15), 18 (n = 15), 28 (n = 16), 32 (n = 16), and 36 (n = 16) weeks' gestation. A subgroup of ten diabetic women was sampled longitudinally through all five gestational ages. The diabetic women were compared with healthy nondiabetic women sampled cross sectionally at 12 (n = 20), 28 (n = 19), and 36 (n = 19) weeks' gestation. Nonpregnant diabetic (n = 22) and nonpregnant nondiabetic women (n = 28) also were studied. Plasma concentrations of the cell adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular endothelial cell adhesion molecule-1 (VCAM-1) were measured by enzyme-linked immunosorbent assay. RESULTS: Significantly higher median (range) concentrations of E-selectin (63.0 [20.2-107.0] ng/mL) and ICAM-1 (281.5 [171.6-778.4] ng/mL) but not VCAM-1 (459.7 [301.0-909.7] ng/mL) were found in nonpregnant diabetic women compared with nonpregnant nondiabetic women (43.5 [18.1-93.2], 243.6 [174.4-329.2], and 476.0 [253.8-929.4] ng/mL, respectively). During pregnancy these significant differences between diabetic and control groups were lost. The median (range) concentration of E-selectin (50.0 [21.2-96.3] ng/mL) was significantly lower in pregnant compared with nonpregnant diabetic women. The plasma concentrations of E-selectin and ICAM-1 did not change significantly with gestation in either diabetic or nondiabetic pregnant groups. Vascular endothelial cell adhesion molecule-1 concentration changed significantly with gestation in the diabetic pregnant group only. CONCLUSION: Circulating concentrations of defined vascular cell adhesion molecules are not increased abnormally in diabetic women with good glycemic control during otherwise uncomplicated pregnancy.

The relationship between colonisation, secretor status and in-vitro adhesion of Candida albicans to buccal epithelial cells from diabetics.

This study investigated whether oral candida infection in diabetics and adhesion of Candida albicans to buccal epithelial cells in vitro were related. Buccal cells from 50 patients with diabetes mellitus showed a significant increase in adhesion of C. albicans strain CDS 88 compared with those collected from 50 non-diabetic controls matched for age, sex and denture status. Oral candida carriage, candida infection and secretor status were also investigated in both groups. The frequency of carriage was increased, but not significantly, and there was a significantly higher incidence of candida infection in diabetic patients compared with controls. Diabetic patients who were non-secretors had a significantly increased frequency of oral candida carriage.

Attenuated neutrophil respiratory burst following acute hypoglycaemia in diabetic patients and normal subjects.

The effects of insulin-induced hypoglycaemia on the neutrophil respiratory burst were investigated in six patients with type 1 diabetes and six non-diabetic control subjects. Plasma glucose reached similar nadirs in control subjects (0.9 +/- 0.1 mmol 1(-1); mean +/- SEM) and diabetic patients (1.2 +/- 0.2 mmol 1(-1)) (NS). The resting neutrophil respiratory burst was similar in control subjects (1.26 +/- 0.15 mV) and diabetic patients (1.03 +/- 0.18 mV) (NS). The neutrophil respiratory burst fell following hypoglycaemia in control subjects and diabetic patients to 0.38 +/- 0.05 mV (P < 0.001) and 0.54 +/- 0.09 mV (P < 0.05), respectively. This fall was significantly greater in control subjects (ANOVA; P < 0.001). Resting neutrophil counts were not significantly different in control subjects (3.2 +/- 0.3 x 10(9) 1(-1)) and diabetic patients (6.1 +/- 1.5 x 10(9) 1(-1)). Following hypoglycaemia, neutrophil numbers increased in control subjects and diabetic patients to 11.5 +/- 1.4 x 10(9) 1(-1) (P < 0.01) and 9.7 +/- 1.7 x 10(9) 1(-1) (P < 0.05), respectively. This increase was significantly greater in control subjects (ANOVA; P < 0.001). These results suggest that the neutrophil respiratory burst is suppressed in response to hypoglycaemia and that this phenomenon is more pronounced in non-diabetic subjects.

Benefits of training junior physicians to detect diabetic retinopathy--the Glasgow experience.

The accuracy and appropriateness of 115 consecutive referrals by non-consultant physicians to a specialist Diabetic Retinopathy Clinic were assessed in a retrospective study. The source of the referrals was masked throughout the study. Referrals were classed as 'appropriate' or 'inappropriate' for patient management, and the referral diagnosis (where specified) was compared with the ophthalmologist's initial assessment. It was graded as 'correct', 'partly correct' and 'incorrect'. Referrals from physicians who had received 40-50 hours of outpatient training in the Diabetic Retinopathy Clinic (group A, n = 49) were compared with referrals from doctors without this special instruction (group B, n = 66). Referral was deemed 'appropriate' in 32 (65%) of group A referrals, but in only 22 (33%) of group B (chi 2 = 11.54, df = 1, P less than 0.001). Referral diagnosis (when expressed) was graded as 'correct' in 28 (67%) of group A referrals compared with only 12 (30%) of group B, being 'incorrect' in 10 (25%) of group B referrals and just two (4.5%) of group A (chi 2 = 12.9, df = 2, P less than 0.005). Regular fundoscopy with accurate assessment and appropriate action is vital to prevent loss of vision in diabetic patients. Short-term outpatient training in a Diabetic Eye Clinic leads junior physicians to more appropriate referral and more accurate referral diagnosis.

Cerebral oedema in diabetic ketoacidosis.

Modern management of diabetic ketoacidosis has reduced mortality of this condition from inevitable death in the pre-insulin era to less than 5% in specialised centres. Most fatalities now reflect the underlying disease which has caused metabolic decompensation, such as acute myocardial infarction, cerebrovascular accident or septicaemia. However patients may still die as a direct result of the metabolic disturbances per se and the rare complication of cerebral oedema in diabetic ketoacidosis is almost invariably associated with fatal outcome.

The hyperglycaemic, hyperosmolar non-ketotic syndrome: some aspects of management.

Hyperosmolar non-ketotic coma is a relatively uncommon but important medical emergency. It is associated with a high mortality, which has changed little over the past twenty years. Approximately half of all patients give no prior history of diabetes and since patients often present with neurological abnormalities, resembling a cerebrovascular accident, the diagnosis can sometimes be delayed or missed. Therefore every patient presenting to hospital with a state of clouded consciousness or objective signs of neurological abnormality, should have a blood glucose estimation performed at an early stage. It has been suggested that a regimen of less aggressive early fluid replacement, with more attention being directed to the associated or underlying problems, may be beneficial to the patient. Claims that the continuing high mortality in non-ketotic coma can be improved by such measures await confirmation.

Management of diabetes resistant to subcutaneous insulin with intravenous insulin via an implanted infusion pump.

Diabetes resistant to conventional subcutaneous insulin injection is a rare complication of insulin-dependent diabetes which poses a major management problem. We report three cases treated for a total of over seven patient years with fully implanted insulin infusion devices. Technical difficulties with the devices and their operation have been substantial but the patients are much improved and hospitalisation has been dramatically reduced. We suggest that implanted insulin pumps are a real treatment option for patients with this unusual syndrome.

Metastatic pancreatic polypeptide producing tumour presenting with diabetes mellitus.

A metastatic pancreatic polypeptide tumour is described which presented clinically with diabetes mellitus. This is the first case to present this way.