Morbidity, mortality, and albuminuria in type 2 diabetic patients: a three-year prospective study of a random cohort in general practice

In a 3-year prospective study, the prevalence of albuminuria and its relationship to macrovascular disease, pre-existing vascular risk factors and mortality rate were studied in a random cohort of 290 patients with Type 2 diabetes mellitus in general practice. Newly occurring micro- or macroalbuminuria was associated with significantly (p less than 0.05) higher systolic blood pressure: median (IQ range) 157 (140-170) vs 150 (130-160) mmHg, in addition to higher serum triglycerides: median (IQ range) 2.71 (1.84-4.25) vs 1.84 (1.35-3.14) mmol l-1, and C-peptide levels: median (IQ range) 1.30 (0.98-2.16) vs 1.10 (0.82-1.58) nmol l-1, at 3-year follow-up. Patients with macroalbuminuria at final examination had significantly higher systolic and diastolic blood pressure, serum triglyceride and beta 2-microglobulin levels, decreased HDL-cholesterol, and a significantly higher prevalence of carotid artery stenoses and peripheral vascular disease. Patients dying from vascular causes showed significantly higher urinary albumin levels at entrance as compared to the surviving patients: median (IQ range): 42.2 (11-249.7) vs 10.4 (4.6-28.0) mg l-1, p less than 0.008, and overall mortality rate was significantly linked with the presence of macroalbuminuria (26% vs 5% in normoalbuminuric patients). A comparison between the results of the initial and the final examination indicated an overall worsening of renal variables (albuminuria: median (IQ range): female 9.5 (4.5-21) vs 13.4 (5.1-39.7) mg l-1, (p less than 0.05); male 13.8 (4.7-34.1) vs 32.6 (8.1-78.7) (p less than 0.001), despite a significant improvement in metabolic variables.(ABSTRACT TRUNCATED AT 250 WORDS)

[Insulin autoantibodies and islet cell antibodies in recently appearing diabetes mellitus type I. Association with age of manifestation and HLA phenotype]

Insulin autoantibody (IAA) and islet cell antibody (ICA) titres were measured in 108 newly diagnosed type I diabetics (49 male, 59 female, mean age 20 [1-38] years) and 103 non-diabetic controls (41 male, 62 female, mean age 23 [16-46] years). IAA titres in the controls were normally distributed, with a mean of 5 +/- 11 nU/ml. The upper limit of normal was established as 49 nU/ml (mean + 4 standard deviations). Raised IAA and ICA titres were present in 45% and 44% of type I diabetics, respectively, with 59% positive for either IAA or ICA or both. IAA were markedly age-dependent, being positive in 70% (26 out of 37) of diabetics under the age of 15 years, and in 32% (23 out of 71) at the age of 15 years or more (P = 0.0004). There was a less marked difference for ICA titres (positive in 62% of patients less than 15 years, and in 35% of those of 15 years of older; P less than 0.01). IAA were significantly more common in HLA DR4 positive patients than in HLA DR4 negative patients (56% vs 11%; Pc less than 0.00015). With regard to age a significant association between IAA and HLA DR phenotype was present only in homozygous (Pc less than 0.03) and heterozygous (P less than 0.0003) patients aged 15 years or older. By contrast, ICA was not significantly correlated with HLA phenotype. These data suggest a genetic predisposition for the development of IAA.

HLA-associated insulin autoantibody formation in newly diagnosed type I diabetic patients

To assess a possible HLA association with anti-insulin autoantibodies (IAAs) in human insulin-dependent (type I) diabetes, 51 newly diagnosed type I diabetic patients (mean age 22 +/- 8 yr) were typed for HLA-DR and HLA-DQ and studied for IAAs before exogenous insulin therapy with a competitive radioimmunoassay (normal range less than or equal to 49 nU/ml). The level of IAAs in 16 patients exceeded our upper limit of normal, and 18 had high-titer islet cell antibodies (ICAs; greater than or equal to 40 Juvenile Diabetes Foundation U). A striking association with HLA-DR4 (DQw3) in both the prevalence and the level of IAAs was found (IAA positivity in patients with DR4/4 vs. DR4 heterozygous vs. non-DR4: 90 vs. 29%, corrected [c] P less than 0.01, vs. 5%, Pc less than 0.0001; IAA positivity in patients with DR4 vs. non-DR4: 50 vs. 5%, Pc less than 0.005; IAA level in patients with DR4/4 vs. DR4 heterozygous vs. non-DR4: 111 vs. 17 nU/ml, Pc less than 0.01, vs. 20 nU/ml, Pc less than 0.0001; IAA level in patients with DR4 vs. non-DR4: 45 vs. 20 nU/ml, Pc less than 0.01). In contrast, none of the DR3+ subjects had IAAs above normal range, except in conjunction with DR4 (DR3 vs. non-DR3: 12 vs. 42%, Pc less than 0.05). However, there was no significant relationship between DR3 and IAAs after correcting for the number of DR4 alleles. No relationship was seen between age of onset, IAA level, and HLA typing in our population, and no relationship was found between ICA positivity and HLA antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

Follow-up of cyclosporin A treatment in type 1 (insulin-dependent) diabetes mellitus: lack of long-term effects

In the Canadian/European randomized controlled study on cyclosporin A (CsA) in recent onset Type 1 (insulin-dependent) diabetes, treatment with the immunosuppressive drug had increased and maintained Beta-cell function and clinical remission during the first 12 months. Following discontinuation of the study drug and double-blinding after a mean of 13.8 months former CsA patients doubled the daily insulin dose within 6 months reaching the level of former placebo patients. The difference in Beta-cell function between the two groups was also lost. Metabolic control (HbA1c) was transiently worse in the former CsA group. Adverse effects of cyclosporin A on systolic blood pressure, haemoglobin levels, serum potassium and creatinine levels also remitted during that time. We conclude that treatment with cyclosporin A for a mean of 13.8 months had no long-lasting effect on the course of Type 1 diabetes persisting beyond drug discontinuation.

[Insulin level--a parameter for risk of arteriosclerosis?]

Surprisingly enough, insulin has recently been suspected of promoting cardiovascular complications provided it becomes effective in excess concentrations at the vascular walls. This applies to both endogenous hyperinsulinemia and insulin substitution performed exogenously with high insulin doses. Several large population studies in non-diabetics--carried out in Helsinki, Busselton and Paris--proved recently that serum insulin concentration is an independent risk predictor for the occurrence of coronary heart disease. According to in-vitro trials, insulin stimulates the proliferation of the smooth muscle cells in vascular media and the lipid synthesis as well as lipid incorporation into the vascular wall. Very recent large-scale population studies in randomly selected type II-diabetics (the Schwabing Study and one performed at Oxford) have revealed a close association between endogenous hyperinsulinemia respectively high exogenous insulin requirement on the one hand and the risk of macroangiopathy or coronary heart disease on the other.

Changes of vitamin D3 serum concentrations at the onset of immune-mediated type 1 (insulin-dependent) diabetes mellitus

Several hormones such as 1,25-dihydroxy-vitamin D3 (1,25-(OH)2D3), alpha-MSH, or ACTH have been found to interact extensively with the immune system. In view of the immune-mediated nature of Type 1 (insulin-dependent) diabetes mellitus, 49 recently diagnosed diabetic patients were investigated in terms of serum 1,25-(OH)2D3-levels, 25-hydroxyvitamin D3(25-(OH)D3), alpha-MSH and ACTH, and compared with 42 healthy controls. A marked decrease of 1,25-(OH)2D3-levels was found at onset of Type 1 (insulin-dependent) diabetes compared to normal controls (39 +/- 2 vs 55 +/- 4 pg/ml, p less than 0.01). Grouping patients according to season (winter or summer) of diabetes onset and blood sampling, it was demonstrated that the decrease of 1,25-(OH)2D3 was primarily present during summer and due to a loss of the seasonal rhythm of this hormone observed in healthy controls (summer: patients vs controls 41 +/- 2 vs 63 +/- 4 pg/ml, p less than 0.001; winter: 37 +/- 3 vs 33 +/- 3 pg/ml, n.s.). Serum concentrations of 25-(OH)D3 were closely correlated with those of 1,25-(OH)2D3, both in controls (r = 0.55, p less than 0.002) and diabetic patients (r = 0.41, p less than 0.05), yielding a similar loss of seasonal variation also of this vitamin D3 metabolite in Type 1 (insulin-dependent) diabetic patients. No difference was found in the mean and median values of alpha-MSH and ACTH between IDDM patients and controls, although patients exhibited much higher variation of alpha-MSH levels than did controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk of progression to diabetes of low titer ICA-positive first-degree relatives of type I diabetics in southern Germany

In a prospective study to evaluate the prevalence and predictive potential of circulating cytoplasmatic islet cell antibodies (ICA) and competitive insulin autoantibodies (CIAA), we screened 406 non-diabetic first-degree relatives of patients with Type I diabetes mellitus (n = 154 for CIAA). The prevalence of ICA was 2.5% (10/406) and of CIAA 0.6% (1/154) in ICA- and 10% (1/10) in ICA+ relatives at initial screening. The titer of ICA positivity in all relatives varied between 1:1 and 1:4. Values of elevated CIAA were 256 nU/ml of the CIAA+/ICA+, and 97 nU/ml of the CIAA+/ICA- relatives (normal range less than or equal to 39 nU/ml). Sera for repeat ICA and CIAA determination was obtained, and 70% of relatives were found to be again ICA+ after 1.5 years, 40% after 3 years, and 10% after 5.7 years. Both CIAA+ relatives were found to be again CIAA+ on follow-up. Intravenous glucose tolerance tests (IVGTT) were performed in all antibody-positive relatives. No decrease in first-phase insulin secretion (1 + 3 min) below the 1st percentile was observed in any of the ICA+ relatives during follow-up. No ICA+, but one CIAA+/ICA- relative had developed Type I diabetes after 5.6 years of follow-up. In summary, these results indicate that low titer ICA (less than 40 JDF units) are often transient and relatives with low titer ICA rarely progress to Type I diabetes. Elevated CIAA appear to be constant over time and associated with increased progression to overt diabetes.

Low-pigment skin type and predisposition for development of type I diabetes

To ascertain whether skin pigmentation type and sensitivity to ultraviolet (UV) light are associated with susceptibility to type I (insulin-dependent) diabetes, 55 type I diabetic patients were examined, 38 new-onset and 17 long-term cases. They were compared to 72 control subjects of the same geographic region and nationality. To evaluate the individual skin pigmentation type, a standardized questionnaire was developed. Reactivity to UV light was determined by a stepwise-graded UV irradiation. Significantly more diabetic patients in southern Germany had blue eyes than nondiabetic control subjects (55 vs. 26%, P less than 0.01), and significantly more diabetic patients had a low-pigment eye color (blue or green) than control subjects (66 vs. 38%, P less than 0.01). In addition, more fair skin color was noted among diabetic versus control subjects (84 vs. 60%, P less than 0.01). In response to UV irradiation, diabetic patients more often showed an increased UV-light sensitivity than control subjects (83 vs. 23%, P less than 0.001). The relative risk for susceptibility to type I diabetes in subjects with low-pigment eye color was 3.1, in subjects with fair skin type 3.4, and in subjects with increased UV-light sensitivity 5.8. The highest risk for the development of diabetes was seen in subjects who had low-pigment eye color and/or increased UV-light sensitivity (95 vs. 51%, P = 0.00002, odds ratio 17.4). We conclude that a low-pigment skin type may predispose for the development of type I diabetes.

[Results of local thrombolysis with special reference to diabetic metabolism]

The influence of diabetes on the primary and long-term success rate after 145 local thrombolyses in peripheral arterial disease stages III and IV was evaluated. 75 patients suffered from thrombotic, 62 patients from embolic occlusions, with eight patients suffering from thrombangitis obliterans. Regarding the localisation of vascular occlusion 0.6% suffered under an occlusion of the iliacal artery, 21% of the femoral artery, 16% of the popliteal artery, 7% of the vessel of the lower limb and 55.4% showed a combined occlusion of the femoral- and popliteal artery and the artery of the lower limb. In cases of embolic occlusions only marginal differences could be observed, while the primary success-rate of thrombotic occlusions showed greater differences between both groups (75% vs. 91%). During the follow-up, no differences between both groups could be established (patency-rate of 79% for both groups). The same applies to the prognostic factors: peripheral run off, length, duration of occlusion and the clinical stage (Fontaine IIb to IV). The remarkable differences between diabetic and non-diabetic patients in cases of occlusions of more than 16 cm (66% vs. 88% in primary and 55% vs. 77% in long-term success) can be explained by the high percentage of diabetic patients with poor run-off and microangiopathy. Regarding the above parameters, primary and long-term results seemed to be less in diabetic patients, even though a long-term patency could be observed in 2/3 of diabetic patients in stages IIb and IV with primary success.

Flow-cytometric detection of human anti-rat insulinoma antibodies in relation to anti-human islet cell and anti-insulin antibodies. Recognition of distinct antigens by antibodies in early type I diabetes

Flow cytometry was recently introduced for the detection of antibodies in human serum to a cultured insulin-secreting rat insulinoma cell line (RINm5F) to investigate humoral immune reactivity in newly diagnosed type I (insulin-dependent) diabetic patients. Fifty-three patients were observed for 6-20 mo after clinical onset of diabetes with a reported duration of symptoms of less than 6 wk. Human anti-RINm5F antibodies were detected in 28%, human anti-islet cell antibodies in 62%, and anti-insulin autoantibodies in 36% of patients before initiation of insulin therapy. Occurrence of human anti-RINm5F antibodies at this stage was correlated with human anti-insulin autoantibodies rather than with the formation of anti-islet cell antibodies. Incidence of anti-RINm5F antibodies in individuals with duration of diabetes greater than 6 wk was 38%, whereas human anti-islet cell antibodies and anti-insulin antibodies became detectable in 72 and 61% of the patients, respectively. These findings are in line with previous reports of immunoprecipitation by human diabetic serums of a 64,000-Mr antigenic structure in freshly prepared rat islet cells. The results suggest a reactivity of distinct classes of antibodies in serums of patients with type I diabetes to disparate antigens on human islet cells and cloned rat insulinoma cells and, moreover, reactivity to insulin as the secreted product. Further characterization of the reacting RINm5F antigens and prospective studies in subjects at risk for diabetes are required to validate the application of RIN cells to the investigation of immune mechanisms involved in the pathogenesis of human type I diabetes.

[Menarche, menstrual cycle and fertility in diabetic patients]

From observations of female type I diabetics, we collected data on menarche, menstrual cycle and fertility. 337 women answered our questionnaire which had been published in journals for diabetic patients. The data were correlated with age, diabetes duration, and the onset of diabetes. The mean age at menarche was inversely correlated with the age of the patients; in diabetics it was 0.8-2 years higher than in the population in which diabetes developed after menarche. As compared to a population of non-diabetics we observed an increase in mean age at menarche of 0.4-1.3 years. The increase was most pronounced if diabetes developed between the age of 3-8 years. The prevalence of primary amenorrhoea in diabetics was 3.6%, in the controls and in diabetics with late onset 1.5%. Irregularities of the menstrual cycle were observed more often in diabetics than in the controls. The prevalences of oligomenorrhoea and secondary amenorrhoea were 14 and 7% in the group of patients with diabetes onset before menarche. In the group with late onset of diabetes the prevalence of secondary amenorrhoea was 12%. Irregularities of the menstrual cycle were found more frequently at the time of diabetes onset, although 76% of the patients had not remarked any change in the frequency of menstrual bleedings. With increasing diabetes duration, the frequency of bleedings normalized. 70.5% of the patients aged 35 or more had spontaneous conceptions, 2.1% were sterile. Both values are not significantly different from the data of the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

[5-year follow-up after endarterectomy of carotid artery thrombosis]

The long-term results of carotid endarterectomy were analysed in 119 patients, operated on between January 1979 and December 1980 (135 endarterectomies; preoperative data analysed retrospectively). 43 patients had been in stage I, 39 in stage IIa, 13 in stage IIb, 4 in stage III, and 20 in stage IV. Perioperative mortality was 0.8%, while hospital mortality was 2.5%. Transitory perioperative neurological deficits occurred in 4.2% of all patients, but no permanent ones. Five years postoperatively 44.5% had died, nearly half (43.4%) of cardiovascular disease. Cerebrovascular disease and tumour each caused 15% of deaths. During the five-year follow-up period 12% of all patients had had transitory ischaemic attacks; 16% had suffered a stroke (in 63% on the operated side). With a high prevalence of risk factors, only the quality of diabetic control (mortality rate of well controlled diabetes 38%, of poorly controlled 70%) and the risk factors heart failure and vascular occlusive disease had a significant influence on the mortality rate. But the mortality rate was significantly lowered with the use of platelet aggregation inhibitors (41.6% vs 72.7%).

Loss of Ia-positive epidermal Langerhans cells at the onset of type 1 (insulin-dependent) diabetes mellitus

Immunocompetent antigen-presenting Langerhans cells were investigated in skin biopsies of 20 short-term Type 1 (insulin-dependent) diabetic patients and compared with 17 matched normal control subjects. Langerhans cells in epidermal sheet preparations were visualized with a monoclonal anti-HLA DR antibody using indirect immunofluorescence. A significant decrease of Langerhans cells/mm2 body surface area was found in 10 patients immediately at the onset of diabetes compared to 10 patients with 6 months duration of diabetes and to normal control subjects (401 +/- 30 vs 559 +/- 43 vs 611 +/- 33, p less than 0.01 and p less than 0.002). There was no significant difference in the number of Langerhans cells between patients with 6 months duration of diabetes and control subjects. Examination of the most likely precursor of Langerhans cells, the blood monocytes, indicated an increase of monocyte counts in Type 1 diabetic patients after 6 months duration (344 +/- 37 cells/microliters vs 191 +/- 31 in control subjects, p less than 0.05) and an inverse correlation between the number of Langerhans cells in skin with the number of monocytes in peripheral blood (at onset: r = -0.73, p less than 0.01, after 6 months of diabetes: r = -0.61, p less than 0.05). In addition, a positive correlation between Langerhans cells and daily insulin dose was noted in patients after 6 months of diabetes (r = 0.76, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Cell-mediated autoimmunity at the onset of insulin-dependent diabetes mellitus (IDDM)

Peripheral blood lymphocytes have been investigated in 20 newly diagnosed type-I diabetics and 10 healthy subjects using monoclonal antibodies. Mononuclear cells were marked with anti-T-lymphocytes (Leu2, 3, 4, 12) and anti-Ia-antibodies (K14, L243) using indirect immunofluorescence. The percentage of circulating K14- and L243-positive cells was significantly higher in all diabetics than in normal controls. An increase in the number of K14-bearing cells was found in newly diagnosed patients with duration of less than 7 days (n = 10) compared with diabetics of longer duration (1 to 8 months; n = 10). Using dual-color immunofluorescence with fluorescein-conjugated anti-T-lymphocytes and rhodamin-conjugated anti-Ia-antibodies it was not possible to identify Ia-antigen bearing cells (Ia cells) as helper or suppressor lymphocytes. In addition, there was no significant difference in the number of Ia cells in diabetics with and without islet cell antibodies. It is concluded that there is evidence of activation of cellular immune response in type I diabetes, particularly in the early days of manifestation. However, previous assumptions that Ia cells represent T-cell activation have to be questioned.

Daily insulin dose as a predictor of macrovascular disease in insulin treated non-insulin-dependent diabetics

In the longitudinal Schwabing study, unselected insulin-treated diabetic patients were followed for major vascular complication (MVC) (stroke, myocardial infarction, gangrene) and asymptomatic, early detectable peripheral vascular disease (PVD). In the group of insulin-treated NIDDM multiple logistic regression analysis revealed the number of daily injected insulin units as a significant predictor for MVC and PVD (t = 1.98; p less than 0.04; x +/- S.D.: PVD yes 57.6 +/- 21.4 U/d; PVD no 44.3 +/- 17.7; age-adjusted univariate p less than 0.001). Daily insulin dose correlated highly significantly with serum triglycerides (r = 0.40, p less than 0.001) as well as with blood glucose (r = 0.33, p less than 0.001). These data suggest that insulin resistance is characteristic for atherosclerotic disease in NIDDM and the hyperinsulinemia-hypertriglyceridemia-syndrome might be a powerful cardiovascular risk factor in diabetes mellitus.

[Local thrombolysis in acute occlusion of a femoropopliteal Gore-Tex bypass]

Occlusion of a femoro-popliteal Gore-Tex-bypass in two patients could be reopened using local low-dose thrombolytic therapy. Apart from the peripheral outflow effective anticoagulation treatment appears to have a deciding influence on long-term results. Application of the thrombolytic selectively to single vessels of the lower leg as well as a post-lysis effect offer the chance for an improvement in outflow. Combination of local lysis with vessel surgery may be an additional alternative for conservation of the extremities.

Insulin degrading enzyme activity and insulin binding of erythrocytes in normal subjects and Type 2 (non-insulin-dependent) diabetic patients

Specific insulin degrading enzyme activity of erythrocytes was determined in relation to erythrocyte insulin binding in 16 healthy subjects, 14 Type 1 (insulin-dependent) and various groups of Type 2 (non-insulin-dependent) diabetic patients (n = 39). Degrading activity was increased in Type 2 diabetic patients on sulphonylureas, as well as in a subgroup with good metabolic control (p less than 0.001) and in patients with secondary failure to oral therapy (p less than 0.02); degrading activity returned to normal in the latter patients after 1 week of insulin treatment. Highest degrading activity was found in insulin-treated, yet insulin-insensitive patients (daily insulin dose greater than 80 U). Degrading activity was significantly correlated in healthy subjects both with circulating insulin concentrations and maximal specific insulin binding. In contrast, in Type 2 diabetic subjects, degrading activity was inversely correlated with serum insulin with no apparent association with maximal specific insulin binding except in those patients given 1 week of insulin treatment. High erythrocyte insulin degrading enzyme activity might be a common feature in the insulin-insensitive Type 2 diabetic patient and might occur subsequent to some aspect of insulin deficiency at the tissue level.

Platelet enzyme activities in diabetes mellitus in relation to endothelial damage

Increased platelet reactivity has been suggested in the pathogenesis of both arteriosclerosis and diabetic microangiopathy. Therefore, platelet function and platelet enzyme activities were assessed in a large group of 357 diabetics (256 patients with IDDM, aged 16-49 and 101 patients with NIDDM, aged 50-78) and 163 matched controls, and related to photographically documented retinopathy (Rd) and to peripheral vascular disease (PVD) as well as to plasma levels of von Willebrand factor (VIII R:Ag) as an indicator of endothelial damage. Patients with IDDM had increased platelet aggregation (PA, expressed as microM ADP threshold concentration) before Rd was detectable in comparison to control subjects (P less than 0.01). PA was further increased in patients with advanced Rd (P less than 0.01), whereas 20 newly diagnosed diabetics with IDDM exhibited normal PA. Patients with minimal Rd did not differ from patients without Rd. Plasma beta-thromboglobulin (reflecting platelet consumption in vivo) was enhanced significantly in patients with Rd only (P less than 0.05), as was malondialdehyde (MDA) production of platelets (as a measure of platelet endoperoxide formation). Factor VIII-related antigen in plasma was already increased in patients without Rd (P less than 0.05), yet more so in patients with Rd (P less than 0.01). Prostacyclin-stimulated adenylate cyclase activity (ACA) of platelets (as an antiaggregatory enzyme system) was twice as high in diabetics with advanced Rd compared with patients without Rd and with controls (P less than 0.01). Significant correlations were found between PA and plasma F VIII R: Hg, MDA production, and ACA of platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

[ECG during rest as an indicator of vascular changes in diabetic patients]

EKG-findings of 186 non-selected diabetic outpatients and 52 control subjects of the age group of 50 to 79 years have been examined in relation to cardiovascular risk factors as well as to peripheral vascular disease (PVD) and carotid artery stenosis (CS). The Whitehall-Criteria of the Minnesota-Code were seen in diabetics (D) approximately twice as frequently as in non-diabetics (C): Minnesota-Code I: D 7% vs C 4%; IV 27% vs 13%; V 25% vs 15%; VII1 2% vs 0%. Beside higher levels of blood glucose and HbAI, diabetics differed from controls mainly by higher systolic blood pressure (p less than 0.001). Furthermore, they showed more signs of PVD and CS. Only in 27% of diabetics normal EKG-findings were seen. In comparison to age-adjusted diabetics with EKG-abnormalities, these patients showed signs of PVD and CS only to a minor degree and lower values were found for systolic (p less than 0,01) and diastolic (p less than 0.05) blood pressure, weight (p less than 0.05), serum triglycerides (p less than 0.02), and markedly higher values for HDL-cholesterol (p less than 0.01). These data show that in diabetics more frequently abnormal EKG-findings are seen and that a normal EKG in diabetics older than 50 years indicates low cardiovascular morbidity and a favorable risk factor profile.

Purification to homogeneity of an insulin-degrading enzyme from human erythrocytes

The purification of an enzyme is described, a protease, from human erythrocytes which degrades insulin with a high specificity at physiological hormone concentrations. Since the enzyme contains free sulfhydryl groups, affinity chromatography on organomercuri-Sepharose proved to be applicable as a valuable step in the isolation procedure. The purification factor amounted to approx. 6000, the yield to 8%. 1mg of purified enzyme was capable of degrading 50 pmol of insulin/min into trichloroacetic acid-soluble split products. The purified insulin-degrading enzyme was shown to be homogeneous, as demonstrated by gel chromatography, gel electrophoresis and isoelectric focusing. The isoelectric points was at pH 5.8. The molecular weight of nativ enzyme was estimated by gel chromatography and gel electrophoresis and found to be about 150 000-160 000, consisting of 4 subunits. Degradation products of insulin eluted from a Biogel P 30 column are smaller than the A-chain of the hormone, suggesting the activity of a protease. The enzyme appears to be specific for insulin in that it does not degrade other peptide hormones such as growth hormone, prolactin, or thyroid-stimulating hormone. Furthermore, the enzyme does not inactivate enzymes such as lactate dehydrogenase, aldolase, fructose 1,6-bisphosphatase, hexosephosphate isomerase or hexokinase.

Muscle triglycerides in diabetic subjects. Effect of insulin deficiency and exercise

Muscle triglycerides and glycogen were measured in biopsy specimens of the vastus lateralis muscle before and after 1 h of ergometric exercise at 50 to 60% of maximal capacity (i. e. at a pulse rate during exercise of 180 minus age) in 3 groups of 19 to 35 year old, non-obese male subjects: 10 normals, 10 insulin dependent diabetic patients in relatively good control and 10 poorly controlled insulin dependent diabetic patients in whom insulin was withdrawn 24 h prior to examination. At rest in all subjects muscle triglyceride content was positively correlated with serum triglycerides(p < 0.001) and blood glucose (p < 0.05), resulting in elevated muscle triglyceride stores in the insulin deficient diabetic patients (17.9 +/- 1.8 mumol/g protein vs. 13.4 +/- 1.3 and 9.4 +/- 1.2 in the normal subjects and the well controlled diabetic patients; p < 0.05 and < 0.001). During exercise, utilisation of muscle triglycerides and glycogen were directly related to content at rest (p < 0.001), including the insulin-deprived patients with decreased glycogen. The decrease of muscle fat was associated with a rise in serum glycerol (p < 0.001) and non-esterified fatty acids (p < 0.001) during exercise.

[Necrotising vasculitis in lympho-plasmocytoid immunocytoma (author's transl)]

A 42-year-old patient died of fulminant necrotising vasculitis with acute renal failure. During life neither paraproteins nor immune complexes or cryo-globulins could be demonstrated in the blood. At necropsy an intraabdominal lympho-plasmocytoid immunocytoma was found as underlying disease.

Peripheral vascular disease in diabetes mellitus and its relation to cardiovascular risk factors: screening with the doppler ultrasonic technique

Data of 623 nonselected diabetic outpatients are presented who were screened for peripheral vascular disease (PVD) and for cardiovascular risk factors. PVD was diagnosed in 15.9% of the diabetic patients (14.4% women and 18.0% men). Nine percent of the patients had signs of marked mediasclerosis at the ankle level. Multivariate statistical analysis revealed that PVD was closely associated with systolic hypertension and also with the duration of diabetes, a relationship that was highly significant (P less than 0.001) for the peripheral type (below the knee) of PVD. Diabetic patients with arterial disease at the pelvic or femoral site exhibited a higher number of cardiovascular risk factors. In contrast, in patients with the peripheral type, significantly higher blood glucose values were found. Therefore, the quality of metabolic control may play an important part in the development of this form of diabetic macroangiopathy.

[Epidemiology of peripheral vascular disease in diabetics (author's transl)]

623 non-selected diabetic outpatients were screened by the Doppler-ultrasonic-method for peripheral vascular disease. Additional angiologic work up was performed to define the location of stenosis and obliteration. 15.9% of the diabetics were shown to have peripheral vascular disease and 57% of those denied claudication. 9% of the patients had signs of mediasclerosis. The predilection of peripheral vascular disease in diabetics for the arteries below the knee (peripheral type) was confirmed in our study. Patients with a pelvic or femoropopliteal type of peripheral vascular disease showed a high frequency of cardiovascular risk factors. An influence of the duration of diabetes on peripheral vascular disease was not evident. In contrast to this, a significant correlation (p less than 0.001) of the peripheral type of peripheral vascular disease-as well as of mediasclerosis--could be demonstrated with the diabetes of long duration. In patients with the peripheral type of peripheral vascular disease significantly more often higher blood sugar volues were found. Thus the quality of metabolic control seems to be of some importance for this form of diabetic macroangiopathy.

An adverse effect of insulin on the oxygen-release capacity of red blood cells in nonacidotic diabetics

Oxyhemoglobin dissociation curves (ODC) were performed on blood from newly diagnosed, nonketotic diabetics prior to and following initial insulin treatment and from ambulatory juvenile diabetics before and after their usual morning insulin. In 10 newly discovered diabetics the average P50 at in vivo pH was normal prior to insulin (26.2 mm Hg), decreased to 24.5 mm Hg (p less than 0.005) on the day following the initial insulin administration, and was within normal limits (26.9 mm Hg) when the diabetes was finally well controlled and red cell 2,3-diphosphoglycerate (2,3-DPG) had risen to elevated levels. Oxygen affinity of hemoglobin was closely correlated with the content of red cell 2,3-DPG (r = 0.61, p less than 0.001) but was unrelated to the level of hemoglobin Alc. In 40 juvenile patients the average P50 was also normal prior to insulin administration but was significantly lower 3-4 hr after they had received their usual insulin dose (p less than 0.001). The study indicates that insulin administration to diabetics with high blood glucose levels may lead to transient decreases in red cell 2,3-DPG and in oxygen-releasing capacity of the red blood cells.

[The effect of combined therapy with buformin and dichloracetate on blood lactate concentrations in diabetics]

In animals, dichloroacetate (DCA) which activates pyruvate dehydrogenase has been shown to diminish increased blood lactate concentrations due to biguanide treatment. In 10 maturity onset diabetics, therefore, the effect of a combined therapy with buformin and DCA (200 mg b.i.d.) was studied on blood lactate concentrations and compared with an analogous pre- and postinvestigation period of 6 days with buformin treatment alone (100 mg b.i.d.). Mean blood glucose concentrations remained the same during all 3 investigation periods. Also, neither fasting nor postprandially significant differences were found in blood lactate and ketones. In association with a standardized ergometer test, however, the rise in blood lactate was significantly smaller (p less than 0.05) while the patients were on buformin plus DCA, compared to the periods when only buformin was given. Furthermore, less ketone bodies appeared to be utilized by the exercising muscle under the influence of the combined treatment (p less than 0.05). These results are in good agreement with animal studies and suggest that DCA might be as effective in decreasing enhanced blood lactate concentrations in biguanide treated man as in animals.

The effect of fructose infusions on the oxygen transport system of human blood

In 9 healthy subjects the erythrocyte 2,3-diphosphoglycerate (2,3-DPG) concentration, which modifies the oxygen affinity of haemoglobin, decreased by more than 25 per cent within 60 minutes of the beginning of a fructose infusion (0.5 g.kg body weight-1.h-1). In contrast erythrocyte adenosine triphosphate (ATP) concentration was unchanged. In spite of the diminished 2,3-DPG concentrations the oxygen affinity of whole blood actually measured remained unaltered. However, at the same time both the arterial and the venous blood pH had fallen by 0.05 or more. In vitro experiments indicated that this fall of erythrocyte 2,3-DPG was not due to a direct effect of fructose on the intra-erythrocytic regulation of 2,3-DPG or to changes indirectly related to the intravenous administration of fructose in vivo, i.e. an increase of the blood lactate/pyruvate ratio or a decrease of plasma inorganic phosphate. It is suggested that two opposing effects on the oxygen transport system of blood are induced by fructose infusions: 1) a displacement of the oxygen dissociation curve to the right due to the Bohr effect 2) a virtually counterbalancing shift of the oxygen dissociation curve to the left due to decreased erythrocyte 2,3-DPG concentrations.

Muscle metabolism during rest and exercise: influence on the oxygen transport system of blood in normal and diabetic subjects

The oxygen dissociation curve shifted less to the right in venous blood draining from muscle in eight insulin-deficient diabetics working at a constant submaximal workload than in seven normal controls (28.7 mm. Hg vs. 30.8 mm Hg; P less than 0.05). This diminution of the in-vivo Bohr effect at the muscle tissue level during exercise in diabetics was due to a significantly smaller decrease of venous blood pH (down to 7.33 vs. 7.27 in normals; P less than 0.05), probably a consequence of an latered muscle metabolism in insulin deficiency. Although no glucose was taken up, even during exercise, and less lactate was produced by insulin-deficient muscle (P less than 0.05), the differences in venous blood pH appeared to be brought about mainly by a different CO2 production of the exercising muscle in the two groups. The response of Krebs cycle activity to exercise in insulin-deficient muscle might have been inadequate, as suggested by the increased 3-hydroxybutyrate/acetoacetate ratio in the venous blood observed in the normal controls but not in the diabetics. Furthermore, proportionally less of the arterial ketone body concentration was utilized by the working muscle in the insulin-deficient diabetics. Changes in erythrocyte 2,3-diphosphoglycerate did not contribute to the differences in the in-vivo Bohr effect.

The oxygen transport system of red blood cells during diabetic ketoacidosis and recovery

Daily evaluations of 8 newly detected ketoacidotic diabetics showed the Bohr-effect of haemoglobin to be decreased by 50% while erythrocyte 2,3-DPG was decreased below 10 mumoles/g Hb. 2,3-DPG correlated strongly with pH during acidosis and with plasma inorganic phosphate (Pi) subsequently to the first insulin administration. Oxygen affinity of haemoglobin, measured as P50 act pH, was unchanged in ketoacidosis compared to the time, however, P50 act pH fell striking (p less than 0.001) and remained decreased up to 7 days depending upon the resynthesis of 2,3-DPG in relation to Pi. The Hill-coefeficient in reflecting the slope of the oxygen dissociation curve was diminished in ketoacidosis (p less than 0.005), and decreased further after pH-normalization (p less than 0.005). There was a close association of n with 2,3-DPG (p less than 0.001) and additionally with Pi at 2,3-DPG-levels below 10 mumoles/g Hb. Based on these findings a decreased erythrocyte oxygen release of one fifth during acidosis and more than one third after pH-correction can be hypothesised. In view of the intimate relation of Pi to the oxygen transport system it is suggesed that treatment of ketoacidosis should include Pi-sugstitution.

The problem of tissue oxygenation in diabetes mellitus. I. Its relation to the early functional changes in the microcirculation of diabetic subjects

The underlying cause leading to the reversible functional changes in the microcirculation of insulin-dependent diabetic subjects early during the disease prior to any clinical signs of retinopathy and nephropathy (functional microangiopathy) is discussed. It is suggested that the initial microvascular dilation observed in diabetics is due to an autoregulatory response to relative tissue hypoxia providing an increased tissue perfusion in order to improve tissue oxygen delivery. Supporting evidence for this suggestion is derived from the findings that diabetics simultaneously may show increased tissue oxygen consumption and decreased ability of the circulating blood to release oxygen to the tissues. The latter defect is likely to be caused by two interrelated factors: 1. an increased proportion of haemoglobin A1c with high oxygen affinity, and 2. difficulties of maintaining a sufficiently high concentration of plasma inorganic phosphate in order to provide an optimal 2,3-diphosphoglycerate (2,3-DPG) content in the erythrocytes. The basal oxygen demand of diabetics may fluctuate even within a few hours dependent upon the state of metabolic control and is increased at times of poor regulation. Hence, diabetics may suffer from innumerable cellular hypoxic injuries, which during the first years of the disease are counteracted in the microcirculation by an autoregulatory response. These microvascular reactions associated with increased plasma permeation may over the years be of major importance for the development of the degenerative microangiopathy in diabetes.