Proportional proinsulin responses in first-degree relatives of patients with type 2 diabetes mellitus

Elevated fasting proinsulin immunoreactive material (PIM) has previously been found in patients with type 2 (non-insulin-dependent) diabetes mellitus. It is not known whether this is a genetic trait or whether it is related to the manifestation of type 2 diabetes. Neither is it clear whether the raised fasting insulin immunoreactivity previously observed in first-degree relatives of patients with type 2 diabetes is due to raised PIM. Furthermore, it has not been investigated whether first-degree relatives have altered PIM responses to different secretagogues. To study this, PIM, insulin and C-peptide were measured in patients with type 2 diabetes, in their first-degree relatives and in healthy control subjects in the fasting state and in relatives and controls during a hyperglycemic clamp. At the end of the hyperglycemic clamp, 0.5 mg of glucagon was given intravenously to stress the beta cells further. Fasting PIM concentrations were significantly higher in patients with type 2 diabetes (P < 0.05). These patients did not have significantly elevated fasting insulin levels when corrected for PIM. In the relatives, fasting insulin concentrations were elevated but PIM levels were normal suggesting that the increase in fasting insulin concentrations reflected an increase in true insulin. The incremental PIM, insulin and C-peptide responses to glucose and glucagon in the relatives were not different from those in the controls. We conclude that elevated fasting PIM levels in patients with type 2 diabetes seem not to be a genetic trait.(ABSTRACT TRUNCATED AT 250 WORDS)

Cognitive function in type 1 (insulin-dependent) diabetic patients after nocturnal hypoglycaemia

Eight Type 1 (insulin-dependent) diabetic patients with no diabetic complications were studied on two consecutive and one subsequent overnight occasions. The aim was to evaluate the influence of nocturnal hypoglycaemia on neuropsychological and reaction time tests the following morning. Hypoglycaemia was induced by i.v. insulin infusion, blood glucose nadir was 1.5 +/- 0.3 mmol/l. Duration of hypoglycaemia (blood glucose less than 3 mmol/l) was 101 +/- 38 min. Whole night sleep statistics for all patients showed no statistical differences between the normoglycaemic and hypoglycaemic nights, however, there was a tendency of prolongation of the second sleep cycle in the nights with hypoglycaemia. Each patient was used as his own control and periods with blood glucose concentration less than 3 mmol/l were compared to exactly the same periods in nights with blood glucose level over 5 mmol/l. During hypoglycaemia the amount of deep sleep was reduced and replaced by superficial sleep and arousals of short duration. Further, the reduction in deep sleep was replaced later at night. Neuropsychological test scores and reaction time measurements in the morning showed no differences between the normoglycaemic and hypoglycaemic nights.

IN CONCLUSION

despite sleep disturbances, nocturnal hypoglycaemia did not impair cognitive function the following morning in Type 1 (insulin-dependent) diabetic patients.

Homogeneity in pattern of decline of beta-cell function in IDDM. Prospective study of 204 consecutive cases followed for 7.4 yr

OBJECTIVE

To study the natural history of beta-cell function from onset of IDDM to expected deterioration of insulin (C-peptide) secretion and to identify different patterns of decline, if any.

RESEARCH DESIGN AND METHODS

A cohort of 204 consecutive newly diagnosed IDDM (clinical criteria) patients were followed prospectively for 7.4 yr (range 6-9 yr), measuring fasting C-peptide at onset, 1, 3, 6, 9, 12, and then every 6 mo until 106 wk (range 104-135 wk). Then, postprandial C-peptide was measured.

RESULTS

Fasting C-peptide was 0.17 nM (range 0.11-0.25 nM) at onset followed by an annual increase rate of 0.16 nM/yr (range 0.06-0.48 nM/yr) to a peak of 0.28 nM (range 0.23-0.34 nM/yr) after 25 wk (range 12-39 wk). The subsequent annual decline rate of fasting C-peptide was 0.08 (0.05-0.12) and of postprandial C-peptide 0.03 nM/yr (range 0.02-0.06 nM/yr). None of these parameters showed bimodality in their distribution. However, some parameters were important. In men, fasting C-peptide at onset was lower, but the initial C-peptide increase rate was more pronounced compared to women. Furthermore, insulin-free remission was related to higher C-peptide levels throughout the study. C-peptide was higher during the 1st yr of diabetes in subjects greater than 30 yr of age at onset compared with younger diabetic patients. Stepwise multiple regression analysis showed that age, male sex, and fasting C-peptide at onset were of some predictive value for the C-peptide levels at 5 yr. However, simple group comparisons revealed no significant differences.

CONCLUSIONS

No major heterogeneity exists in the pattern of decline of beta-cell function in IDDM, although small differences in pattern could be identified in both sexes, in different age-groups, and in relation to achieving insulin-free remission.

Nasal glucagon in the treatment of hypoglycaemia in type 1 (insulin-dependent) diabetic patients

The aim of this study was to compare the effect of nasally administered glucagon in doses of 1 (A) and 2 mg (B), with 1 mg glucagon administered intramuscularly (C) in 12 C-peptide-negative IDDM patients. Spontaneous recovery (D) from insulin-induced hypoglycaemia in the same patients was used as reference. The mean age was 31.1 (21-48) years, diabetes duration 10.8 (2.7-31) years and HbA1c 7.7 (6.5-9.8)%. Hypoglycaemia was induced by i.v. insulin infusion. When blood glucose (BG) reached about 2 mmol/l either glucagon was administered or the patients recovered spontaneously. BG nadir was 1.6 (1.1-2.3) mmol/l. BG increments during the first 15 min after glucagon administration were: (A) 1.9 +/- 0.7 (0.4-3.0); (B) 2.5 +/- 0.7 (1.5-3.5); (C) 2.5 +/- 1.0 (1.2-4.7); and (D) 0.3 +/- 0.4 (0-1.0) mmol/l, respectively. All treatments were more effective, measured as increments in BG, than spontaneous recovery, P less than 0.00001. There was no difference between nasal treatment with 2 mg (B) and i.m. treatment (C), both being more effective than 1 mg (A) nasal treatment, P less than 0.1. BG continued to increase up to 10 mmol/l 90 min after i.m. glucagon administration, whereas it stabilized at a level of 4.6-6 mmol/l, 30-45 min after nasal administration. Eighty percent of the patients had side-effects to nasal administration - local irritation, rhinitis or sneezing. Half of the patients sneezed, without correlation with the delivered dose of glucagon. None of the patients had side-effects which would preclude further treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined deficiencies of the pyruvate dehydrogenase complex and enzymes of the respiratory chain in mitochondrial myopathies

In six patients with mitochondrial (encephalo-) myopathy investigations of skeletal muscle revealed a defect of pyruvate dehydrogenase complex (PDHC) in combination with one or more respiratory chain complex deficiencies. A combination of defects of this kind has not been reported previously. Five of the six patients presented within the 1st year of life and had a severe clinical course. Intrafamilial variability of the clinical course in dizygotic twins both suffering from a cytochrome c oxidase deficiency and one of them also from a PDHC deficiency suggests an additional effect of PDHC deficiency on the clinical symptoms. Immunoblot studies of PDHC in five of the patients revealed no abnormalities in their subunit pattern, rendering a defect of mitochondrial protein import or assembly unlikely. The finding of a combined PDHC and respiratory chain deficiency has implications for the diagnostic approach, for therapy and genetic counselling. The exact pathogenetic mechanism of this combination of defects remains to be elucidated.

Endocrine emergencies. Hypoglycaemia

Hypoglycaemia is possibly the most frequent metabolic emergency, in that insulin-induced hypoglycaemia is a common side-effect of treatment of a common disease. The symptoms are partly sympathetic and related to the release of catecholamines. These symptoms include sweating, tremor, palpitations, sensation of hunger, restlessness and anxiety. Other symptoms are caused by an insufficient supply of glucose to the brain, resulting in neuroglucopenia with symptoms like blurred vision, weakness, slurred speech, vertigo and difficulties in concentration. Symptom recognition is the primary and most effective defence against cerebral dysfunction which is the ultimate consequence of hypoglycaemia. Even in insulin-treated diabetic patients symptom failure might occur. Patients who experience severe episodes of hypoglycaemia do not constitute a special subgroup of patients. However, near-normalization of blood glucose levels have resulted in an increase in the incidence of severe hypoglycaemia. Moreover, the threshold for hormonal counter-regulatory responses in adrenaline, growth hormone and cortisol is lowered after a period of strict metabolic control in insulin-dependent diabetic patients. The glucose level at which the patients become subjectively aware of hypoglycaemia is correspondingly reduced. Other reasons for hypoglycaemia to occur are oral hypoglycaemic agents, especially sulfonylureas which may be potentiated by other drugs. Prolonged hypoglycaemia may be seen after first-order sulfonylureas, and may indicate glucose infusion as treatment. Next to insulin and sulfonylurea, ethanol is the most common cause of hypoglycaemia. In non-diabetics, hypoglycaemia will typically develop 6-24 h after a moderate or heavy intake of ethanol by a person who has had an insufficient intake of food for 1 or 2 days. Insulin-producing tumours, insulinomas and non-islet cell tumours may also be reasons for hypoglycaemia in non-diabetics. Treatment of mild episodes of hypoglycaemia is intake of fast-absorbing carbohydrates. Severe episodes can be treated with either i.v. dextrose or glucagon injected i.m. or i.v. The glycaemic response and recovery of a normal level of consciousness is 1-2 min slower after glucagon than after glucose.

Respiratory tract infections due to different rhinovirus serotypes and the influence of maternal antibodies on the clinical expression of the disease in infants

Rhinoviruses were isolated from nasopharyngeal secretions of 49 children hospitalized because of severe respiratory tract infection. The isolates were typed using 90 type-specific antisera. No obvious relation between certain serotypes and the severity of illness was found. Serum samples were drawn from all children simultaneously with the nasopharyngeal secretions and screened for the presence of type-specific neutralizing antibodies. Children aged 1 week to 6 months had higher neutralizing antibody titers and revealed a lower degree of morbidity than older children. The decline of neutralizing serum antibodies with increasing age was correlated with a higher incidence of severe disease in those aged 7-12 months. Nevertheless, also in this age group children with mild clinical courses of disease were observed despite a low concentration or an absence of neutralizing serum antibodies. This indicates that not only neutralizing serum antibodies, but other factors also influence the clinical expression of RHV-induced disease.

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)

Nocturnal electroencephalogram registrations in type 1 (insulin-dependent) diabetic patients with hypoglycaemia

Eight Type 1 (insulin-dependent) diabetic patients with no diabetic complications were studied overnight for two consecutive and one subsequent night with continuous monitoring of electroencephalogram and serial hormone measurements. The aims were: 1) to evaluate the influence of spontaneous and insulin-induced hypoglycaemia on nocturnal electroencephalogram sleep-patterns and, 2) to evaluate counter-regulatory hormone responses. Spontaneous hypoglycaemia occurred on six nights (38%) with blood glucose concentrations less than 3.0 mmol/l and on four nights less than 2.0 mmol/l. All the patients experienced insulin-induced hypoglycaemia with a blood glucose nadir of 1.6 (range 1.4-1.9) mmol/l. The electroencephalogram was analysed by a new method developed for this purpose in contrast to the traditional definition of delta-, theta-, alpha- and beta-activity. The blood glucose concentration could be correlated to the rank of individual electroencephalogram-patterns during the whole night, and specific hypoglycaemic amplitude-frequency patterns could be assigned. Three of the eight patients showed electroencephalogram changes at blood glucose levels below 2.0 (1.6-2.0) mmol/l. The electroencephalogram classes representing hypoglycaemic activity had peak frequencies at 4 and 6 Hz, respectively, clearly different from the patients' delta- and theta-activity. The changes were not identical in each patient, however, they were reproducible in each patient. The changes were found equally in all regions of the brain. The three patients with electroencephalogram changes during nocturnal hypoglycaemia could only be separated from the other five patients by their impaired glucagon responses. Against this background the possibility of protection by glucagon, against neurophysiologic changes in the brain during hypoglycaemia may be considered.

Glucose-induced insulin response is reduced and proinsulin response increased in healthy siblings of type 1 diabetic patients

Glucose-stimulated insulin and proinsulin responses, and insulin sensitivity, were studied in 30 HLA identical, 38 HLA haplo-identical, and 25 HLA non-identical, healthy islet-cell-antibody negative siblings of Type 1 diabetic patients. The results were compared with 41 age- and sex-matched healthy subjects with no diabetes in the family. The proinsulin-corrected insulin response to an intravenous glucose infusion test was significantly lower among siblings when insulin sensitivity was taken into account (1.65 (inter-quartile range 1.20-2.64) vs 2.18 (1.65-3.28) nmol mmol-1 min, p = 0.04). Proinsulin values were consistently higher among siblings than among control subjects (peak values 50.0 vs 38.0 pmol l-1 (p = 0.004)). When proinsulin release was corrected for individual insulin sensitivity this difference remained. The results suggest disturbed islet B-cell function, unrelated to HLA identity or the presence of circulating islet cell antibodies.

Separation and quantitation of serum proinsulin and proinsulin intermediates in humans

Two reversed-phase high-performance liquid chromatographic (RP-HPLC) systems were developed for the separation of human insulin, proinsulin and the major proinsulin intermediates. The individual components were quantified using two enzyme-linked immunosorbent assays for insulin and proinsulin immunore-active material (PIM) after (passive) evaporation of the organic modifier. Serum samples from normal subjects and patients with non-insulin-dependent diabetes mellitus were immunopurified and analysed in one of the RP-HPLC systems. The proportion of PIM relative to insulin immunoreactive material was higher in the diabetic patient compared with that in the normal subject. In both, PIM was heterogeneous, consisting of intact proinsulin and des-proinsulin intermediates.

Glycaemic thresholds for hypoglycaemic symptoms, impairment of cognitive function, and release of counterregulatory hormones in subjects with functional hypoglycaemia

Nine patients with food-relieved hypoglycaemic symptoms, in whom insulinoma and other organic diseases presenting with hypoglycaemia had been ruled out, and nine matched controls, participated in the study. Subjects were studied during a 5-h controlled (Biostator) insulin-induced (1-2 mU kg-1 min-1) hypoglycaemic clamp. After 1 h of euglycaemia, we aimed to lower the glucose level in arterialized venous blood in a stepwise manner at 30-min intervals to 3.5, 3.0, and 2.0 mmol l-1, and to withhold these levels for a further 30 min. At euglycaemia and at the end of the latter steps, the visual reaction time and cognitive function (digit span, letter cancellation and trail making) were tested, together with recording symptoms and signs of hypoglycaemia. Counter-regulatory hormones were measured at 20-min intervals. In the patients, clinical signs and symptoms of hypoglycaemia developed at median blood glucose levels of 2.6-2.8 and 2.8-3.1 mmol l-1, respectively. By contrast, the blood glucose levels were 0.4-0.8 mmol l-1 lower in control subjects (P less than 0.05). Similarly, the median threshold for deterioration of visual reaction time was 2.8 mmol l-1 in patients and 2.1 mmol l-1 in controls (P less than 0.01). A similar trend was observed for the results of the neuropsychological tests. Visual reaction time deteriorated in all subjects, whereas the cognitive function of some of the subjects in each group remained unchanged during hypoglycaemia. The glycaemic thresholds for release of cortisol, glucagon and growth hormone were significantly higher in patients (P less than 0.05), whereas the thresholds for catecholamine release showed no significant difference from controls. Despite the comparable glucose infusion rates required to sustain each of the hypoglycaemic levels in the two groups, the control subjects achieved lower glucose levels, suggesting that there is resistance to insulin or glucose in functional hypoglycaemia. In conclusion, the present study suggests that the existence of a higher threshold for symptoms and signs, as well as for deterioration of brain function, may explain every-day hypoglycaemic symptoms, despite normal glucose levels, in subjects with functional hypoglycaemia. However, the hypothesis should be tested further using a blinded approach, including euglycaemic control studies.

Symptomatic hypoglycaemia in 411 type 1 diabetic patients

The frequency of symptomatic hypoglycaemic episodes was studied in 411 randomly selected conventionally treated Type 1 diabetic out-patients. Between two consecutive visits to the out-patient clinic each patient filled in a questionnaire at home. The number of hypoglycaemic episodes was then recorded prospectively in a diary for 1 week. From the questionnaires, the (retrospective) frequencies of mild and severe symptomatic hypoglycaemia were 1.6 and 0.029 episodes patient-1 week-1. From the diaries, the (prospective) frequencies of mild and severe hypoglycaemic episodes were 1.8 and 0.027 patient-1 week-1. Symptomatic hypoglycaemia was more frequent on working days than during weekends (1.8:1) and more frequent in the morning than during the afternoon, evening, and night (4.5:2.2:1.4:1). The symptoms of hypoglycaemia were non-specific, heterogeneous, and weakened with increasing duration of diabetes. During their diabetic life, 36% of the patients had experienced hypoglycaemic coma. The frequency of hypoglycaemia was positively, but only weakly, correlated with insulin dose, number of injections, percentage unmodified insulin of the total dose, and HbA1c (mild hypoglycaemia only). The frequency was also negatively, but weakly, correlated with age and HbA1c (episodes with coma only), but not correlated with sex, duration of diabetes, or patients' ratings of worries about mild and severe hypoglycaemia.

Counterregulatory hormonal response to insulin-induced hypoglycaemia in insulin-dependent diabetic patients: a comparison of equimolar amounts of porcine and semisynthetic human insulin

The aim of the present study was to compare the degree of hypoglycaemia, the hypoglycaemic symptom score and counterregulatory responses to equimolar amounts of intravenously administered porcine and semisynthetic human insulin in a double-blind crossover study in insulin-dependent diabetic patients. After overnight stabilization of blood glucose to approximately 6 mmol l-1, insulin was infused from 06.00 hours at such a rate as to keep the blood glucose concentration constant at 6 mmol l-1. At 09.00 hours hypoglycaemia was induced by increasing the infusion rate to give a blood glucose level of 2 mmol l-1 within about 60 min. The individual infusion rate from the first test was repeated in the second test, 1 week later. Blood glucose minimum levels were 2.1 (range, 1.3-2.9) and 2.1 (1.3-2.8) mmol l-1 for porcine and human insulin, respectively. The insulin concentrations at blood nadirs were 107 (66-180) and 107 (56-184) pmol l-1, respectively, for porcine compared to human insulin (NS). Symptom scores at minimum blood glucose concentrations were 43 and 46, respectively, with a maximal difference in intensity of 1 point in each patient. There were no statistical differences in the counterregulatory responses of glucagon, epinephrine, norepinephrine, cortisol, growth hormone, prolactin, beta-endorphine or in serum-potassium decreases. Patients were unable to discriminate between the two forms of insulin. It is concluded that there are no differences between porcine and semisynthetic insulin with regard to glucose fall, hormonal counterregulation or symptom scores, when the two forms of insulin are administered intravenously in equimolar amounts.

The relationship between symptomatic and biochemical hypoglycaemia in insulin-dependent diabetic patients

The relationship between symptomatic (subjective feelings) and biochemical (blood glucose concentration less than 3 mmol l-1) hypoglycaemia was studied in 66 randomly selected insulin-dependent diabetic out-patients under normal conditions of daily life with conventional insulin injection regimens. The patients (a) collected 7-point diurnal blood glucose profiles at home on three consecutive days and then once weekly for 3 weeks, (b) indicated whether they felt hypoglycaemic at sampling times, and (c) collected extra samples if they felt hypoglycaemic at any time during the study period. The weekly frequencies of symptomatic and biochemical hypoglycaemia were 0.99 and 1.75 per patient, respectively. Biochemical hypoglycaemia was present in 29% of the symptomatic episodes, and symptomatic hypoglycaemia accompanied 16% of the biochemical episodes. Symptomatic hypoglycaemia was experienced at a median blood glucose concentration of 3.4 mmol l-1 (range 1.4-14.9 mmol l-1). Fifty per cent of both symptomatic and biochemical episodes occurred before lunch, while the remainder were evenly distributed throughout the day. The occurrence of biochemical hypoglycaemia, but not of symptomatic hypoglycaemia, was inversely correlated with HbA1c and median blood glucose concentration. Thus symptomatic hypoglycaemia is an unreliable indicator of biochemical hypoglycaemia and of the degree of glycaemic control. Blood glucose measurements are a prerequisite for the diagnosis of hypoglycaemia.

Acute actions of sulfonylurea drugs during long-term treatment of NIDDM

The acute effect of sulfonylurea drugs during long-term treatment was evaluated in two separate studies. In the first study, the levels of plasma glucose, insulin, and C-peptide were measured after intake of 10 mg glyburide alone or together with a standardized mixed meal in 10 non-insulin-dependent diabetes mellitus (NIDDM) patients treated with 10-20 mg glyburide/day for greater than 2 yr. There was no acute effect of glyburide on the insulin and C-peptide responses to the meal or during continued fasting, indicating the absence of an acute insulinotropic action of glyburide during chronic treatment. The glucose increase after the meal was also unchanged, but a significant glucose reduction was found after glyburide intake during continued fasting, suggesting a sustained acute extrapancreatic (hepatic) effect. In the second study, the diurnal glycemic excursions in 8 NIDDM patients chronically and continuously (24 h/day) exposed to glipizide (2.5-7.5 mg 3 times/day) were similar when the drug was taken 30 min before each of the three main meals and when taken immediately before the meals. It is concluded that there is no acute insulinotropic action of sulfonylurea drugs during chronic continuous exposure, whereas an acute extrapancreatic action may prevail. During such exposure, there seems to be no clinical benefit in taking a sulfonylurea 30 min before rather than at the start of a meal.

[Immunosuppression with cyclosporin induces clinical remission and improved beta cell function in patients with newly diagnosed insulin-dependent diabetes. A national and international multicenter study]

A prospective, randomized, double-blind, placebo-controlled international multicenter trial including 188 newly diagnosed insulin-dependent diabetic (IDDM) patients was undertaken with the aim of investigating whether immunosuppression for one year with ciklosporin (Cs) could induce and maintain clinical remission and improvement of beta-cell function. The relative odds for non-insulin-requiring remission at one year were increased approximately five times in the Cs-treated group. After three months Cs-treated patients achieved more than a doubling of beta-cell function compared to baseline than did placebo-treated patients, and the Cs-treated group maintained this improvement in beta-cell function for 12 months, whereas the placebo-group lost beta-cell function during the same period. Short duration of disease (less than or equal to six weeks of symptoms, less than or equal to two weeks of insulin treatment) was associated positively with remission, as was an elevated proinsulin/C-peptide ratio, especially in patients with the tissue-type HLA-DR 3,4; 4,X and X,X. Cs-treatment inhibited the formation of antibodies against insulin and islet cell components, but islet cell antibody status at entry was not predictive of remission. Cs-treatment caused a reversible decrement of kidney function as measured with serum creatinine and the calculated creatinine clearance, but studies of renal physiology and kidney biopsies performed on a limited subset of patients indicated that Cs treatment in IDDM patients for one year induced a slight chronic nephropathy in some of these.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of dexamethasone on glucose-induced insulin and proinsulin release in low and high insulin responders

We compared the effects of dexamethasone-induced insulin resistance on B-cell secretory performance in 12 low insulin responders (LIR) and in eight high insulin responders (HIR). A hyperglycemic clamp (120 minutes) was performed before and after the subjects had ingested dexamethasone 3 mg x 2 for 2 1/2 days. Fasting levels of blood glucose increased from 4.60 +/- 0.13 to 5.74 +/- 0.23 mmol/L after dexamethasone in LIR and from 4.37 +/- 0.18 to 5.26 +/- 0.13 mmol/L in HIR. Dexamethasone treatment increased fasting levels of total immunoreactive insulin (IRI), C-peptide, and proinsulin, as well as the proinsulin to IRI ratio to a similar degree in LIR and HIR. The amount of glucose infused to uphold hyperglycemia during the clamp decreased by 54% after dexamethasone in LIR and by 46% in HIR. Mean level of stimulated IRI during the clamp increased after dexamethasone by 43% in LIR and by 53% in HIR. Mean level of stimulated C-peptide increased by 11% (not significant) in LIR and by 24% in HIR. Mean level of stimulated proinsulin increased by 86% in LIR and by 93% in HIR. The effects of dexamethasone on insulin secretion varied among individuals, since steroid treatment failed to affect IRI responses to glucose in two LIR and two HIR. The magnitude of dexamethasone effects on secretion was not correlated to pre-dexamethasone insulin sensitivity as assessed by a somatostatin-insulin-glucose infusion test (SIGIT) or by M/I (glucose infused/insulin level) ratios of the control clamp.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring of blood glucose concentration in subjects with hypoglycaemic symptoms during everyday life

OBJECTIVE

To study the persistence of hypoglycaemic symptoms, changes in blood glucose concentrations, and the relation between reported symptoms and measured blood glucose values in functional hypoglycaemia.

DESIGN

Re-evaluation of symptoms in patients admitted consecutively with suspected hypoglycaemia followed by a case-control study.

SETTING

The Steno Memorial Hospital in Gentofte, Denmark, which specialises in the diagnosis and treatment of and research on endocrine disorders, including hypoglycaemia.

PATIENTS

21 Subjects admitted consecutively with hypoglycaemic symptoms that were relieved by eating in whom insulinoma and other organic disorders presenting with hypoglycaemia had been ruled out. Twelve of these subjects with persistent symptoms entered the case-control study, as did a matched control group.

INTERVENTIONS

Four days of monitoring blood glucose concentrations at home, six daily samples being taken in fixed relation to meals by the finger prick method. Extra samples were taken when symptoms occurred.

MAIN OUTCOME MEASURES

Blood glucose concentration, glycated haemoglobin concentration, and within subject variation in measured values.

RESULTS

After one to three years of observation 19 of the 21 subjects still had symptoms. Six out of 12 subjects experienced hypoglycaemic symptoms during the controlled study. Blood glucose concentration ranged from 3.7 mmol/l to 7.5 mmol/l during these episodes. Changes in blood glucose concentration, mean blood glucose concentrations at each time point, within subject variation in the measured values, and glycated haemoglobin concentration were not significantly different in all patients compared with the control subjects and in patients with symptoms during the study compared with controls.

CONCLUSION

Hypoglycaemic symptoms during everyday life in apparently healthy subjects are persistent but are not related to chemical hypoglycaemia.

Proinsulin and C-peptide at onset and during 12 months cyclosporin treatment of type 1 (insulin-dependent) diabetes mellitus

An increased proinsulin to C-peptide molar ratio at the onset of Type 1 (insulin-dependent) diabetes mellitus has been suggested. We studied fasting proinsulin levels and proinsulin/C-peptide ratios in the newly diagnosed diabetic subjects participating in the Canadian/European placebo controlled cyclosporin study at entry, during the one year treatment period and six months of follow-up. Available entry data from 176 out of the 188 allocated patients were compared to 60 age and weight matched control subjects. Fasting proinsulin was significantly elevated in male patients compared to male control subjects (p less than 0.01), whereas the levels only tended to be elevated in female patients. The proinsulin/C-peptide ratio was three to fourfold elevated in the diabetic groups of both sexes, (p less than 0.001). Further, proinsulin and C-peptide were studied in 83 cyclosporin and 86 placebo-treated subjects during the trial and follow-up. An additional increase of proinsulin/C-peptide ratio was observed during the first three months of placebo treatment. It remained constantly high for nine months and then declined to entry level. This pattern was not seen in the cyclosporin-treated group, where the ratio was unchanged during the 12 months trial and follow-up. The effect of cyclosporin on the induction of non-insulin requiring remission was unrelated to fasting and glucagon stimulated C-peptide levels at entry, whereas 64% of the cyclosporin-treated against 28% of the placebo-treated subjects (p less than 0.01) went into remission if the proinsulin/C-peptide ratio at entry was above 0.024.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of the unstable Hb Genova (beta 28 Leu----Pro) in an Arab child associated with severe haemolytic anaemia and growth retardation

The first case of unstable Hb Genova from North Africa is described. It was found in a 13-year-old girl from Libya suffering from chronic Heinz body haemolytic anaemia and growth retardation. The available data strongly suggest that this case represents a new example for a spontaneous mutation.

[Hypoglycemic effects of equimolar quantities of semisynthetic human and porcine insulin in insulin-dependent diabetic patients]

In some diabetic patients, transition from porcine insulin (PI) to human insulin (HI) has resulted in alterations or non-appearance of the usual hypoglycaemic symptoms. The authors have, therefore, undertaken a double-blind cross-over trial with induction of hypoglycaemia with semisynthetic HI and PI administered in equimolar quantities to eight insulin-dependent men. Prior to induction of hypoglycaemia, the blood glucose (BG) was stabilized at approximately 6 mmol/l. At the time 0, the BG was 5.9 (5.4-7.1) mmol/l and 6.2 (4.8-7.1) mmol/l (NS), BS-nadir was 2.1 (1.3-2.9) mmol/l and 2.1 (1.3-2.8) mmol/l PI versus HI. At the time -15 minutes and at BG-nadir, assessment of symptoms and neuropsychological testing were performed. The total symptom scorings were identical for the two types of insulin, the maximum intraindividual difference was +1 on a scale from 0 to 3. Cognitive function was reduced significantly in hypoglycaemia with no differences for the types of insulin. The conclusion is that, in insulin-dependent diabetic patients, no differences in hypoglycaemic effects were observed between PI and HI after intravenous administration of equimolar quantities.