Medical risk factors in diabetic patients with foot ulcers and severe peripheral vascular disease and their influence on outcome

The association between medical risk factors and the outcome of foot ulcers was evaluated in 208 consecutive diabetic patients with severe peripheral vascular disease (systolic toe blood pressure < or = 45 mm Hg). All patients were treated and followed by the same foot care team. Eighty patients healed primarily, 83 healed after a minor or major amputation, and 45 died. The systolic toe blood pressure was higher among primary healed (30 +/- 13 mm Hg) compared with amputated (22 +/- 15 mm Hg; p < 0.001) and deceased patients (20 +/- 14 mm Hg; p < 0.001). The patients were comparable regarding age, sex, and diabetes and wound duration. Only 41 (19%) patients had intermitten claudication, whereas 153 (77%) lacked palapble pedal pulses, 36% of whom healed primarily. Rest pain occurred in 72 (33%) patients, 38 (47%) of whom had an amputation and 18 (25%) who healed primarily (p < 0.01). Peripheral edema and proteinuria were more common among patients who healed after amputation compared with those who healed primarily (p < 0.001 and p < 0.01, respectively). Signs of sensory neuropathy were found in 158 (77%) patients. There were no differences concerning cardiovascular disease, smoking habits, or short-term metabolic control between patients who healed primarily or after an amputation. In conclusion, diabetic patients with foot ulcers and severe peripheral vascular disease with low systolic toe blood pressure were not excluded from the possibility of primary healing. The most important risk factors for amputation were a systolic toe pressure of less than 30 mm Hg, peripheral edema, rest pain, and proteinuria.

Regional cerebral blood flow in normal man during insulin-induced hypoglycemia and in the recovery period following glucose infusion

The effect of moderate hypoglycemia (p-glucose, 2.0 +/- 0.3 mmol/L; mean +/- SD) on regional cerebral blood flow (rCBF) was studied in a group of 10 healthy, right-handed men (aged 23 to 28 years) using an intravenous xenon 133 single photon emission computed tomography technique (SPECT). After 10 minutes of hypoglycemia, global CBF had increased to 46.3 +/- 9.6 mL/100 g/min compared with the initial normoglycemic flow of 38.6 +/- 6.8 mL/100 g/min (P less than .01). The relative distribution of the rCBF changed significantly (P less than .05, ANOVA) from before to during hypoglycemia. Of the 10 regions analyzed, the highest increments in rCBF during hypoglycemia were found in the frontal (21.5% +/- 15.2%) and parietal (20.6% +/- 14.2%) lobes, and the lowest (10.7% +/- 9.4%) were found in the pons/brainstem regions. The increase in rCBF persisted for 15 minutes after normalization of blood glucose. The persisting high flow after hypoglycemia affected all regions, but a further 10.1% +/- 7.2% increase was observed in the pons/brainstem area (P less than .05). The CBF was significantly higher in the right compared with the left hemisphere (2.8%, 1.2%, and 3.9%, respectively; P less than .05) in all measurements. A decrease in brain volume was found at the final examination, compared with the hypoglycemic state (2.6%; P less than .05). It is concluded that moderate hypoglycemia leads to a marked increase in CBF and in the relative distribution of rCBF, which persists in the immediate period after normalization of the blood glucose level.

Irreversible progression of severe retinopathy in young type I insulin-dependent diabetes mellitus patients after improved metabolic control

The impact of metabolic control on the development of rapidly progressive severe retinopathy was studied in 14 young type I insulin-dependent diabetes mellitus (IDDM) patients. Glycosylated hemoglobin (HbAlc) levels 45 months prior to and 12 months after the diagnosis of retinopathy were compared with HbAlc levels in 17 type I IDDM patients with no or minimal background retinopathy, matched for age and duration of diabetes. HbAlc levels were generally higher in patients with severe retinopathy (p less than 0.05) from 39 months until 6 months before the diagnosis of retinopathy. Thereafter, there was a gradual decrease in HbAlc levels reaching the same level as in control patients 6 months after diagnosis of retinopathy. Patients with severe retinopathy required higher doses of insulin prior to the diagnosis of retinopathy (p less than 0.05), but the insulin requirement decreased, and 12 months afterward, the insulin dosage was similar to patients with background retinopathy. Systolic blood pressure levels were slightly increased and higher in patients with severe retinopathy compared with control patients from 18 months before to diagnosis of retinopathy (p less than 0.05). Diastolic blood pressure levels likewise differed at 18 and 12 months before and at the time of diagnosis of retinopathy as well as 12 months afterward (p less than 0.05); however, no differences were seen in urinary albumin or serum creatinine levels between the groups. Thus, years of poor metabolic control, drastically improved, preceded the development of irreversible severe retinopathy in these young type I IDDM patients.

Neuropsychological performance differs between type 1 diabetic and normal men during insulin-induced hypoglycaemia

Cerebral function was measured with a neuropsychological test battery before, during, and after insulin-induced hypoglycaemia (blood glucose approximately 2.0 mmol l-1) in 10 male Type 1 diabetic patients (age 20-43 years, duration of diabetes 14 (2-30) years) and in 12 normal men. There were no group differences in neuropsychological results at normal glucose levels. Significant effects of hypoglycaemia were found in reaction-time measures (p less than 0.001) and in other tests requiring speed and attention (p less than 0.001), in verbal fluency (p less than 0.05), and short-term memory (p less than 0.001). Significant group effects and interactions (p less than 0.05) revealed that the diabetic patients were generally more affected by hypoglycaemia than the normal subjects. This might have been partly due to the larger absolute decrease in blood glucose level in the diabetic patients, although the rate of glucose decrease was not related to performance in either group. Thus, the diabetic brain might be more vulnerable to hypoglycaemia, perhaps through the persistent impact of repeated hypoglycaemic episodes, although no neuropsychological deficit is demonstrable at normal blood glucose levels.

Growth hormone levels in the basal state and after thyrotropin-releasing hormone stimulation in young type 1 (insulin-dependent) diabetic patients with severe retinopathy

Sixteen young patients with type 1 diabetes mellitus and rapidly progressive severe retinopathy were examined regarding serum levels of growth hormone before and after the i.v. administration of 200 micrograms thyrotropin-releasing hormone (TRH). Serum IGF I, HbA1c, blood pressure, urinary albumin, and serum creatinine levels were also measured. The control group consisted of type 1 diabetic patients matched for age, duration of diabetes and metabolic control with no or minimal background retinopathy. The results show that basal growth hormone levels were above normal in both groups, and that there was a paradoxical increment in growth hormone levels after TRH stimulation (p < 0.05) in patients with severe retinopathy, but the values did not differ from patients with background retinopathy. IGD I levels were normal in all patients but one, and no differences were seen between the two groups. HbA1c, serum creatine, blood pressure, and urinary albumin levels were similar in the groups but patients with severe retinopathy were treated with more insulin (p < 0.001). Thus, neither abnormal growth hormone levels, nor IGF I, seems to be associated with the development of severe retinopathy in young type 1 diabetic patients.

Tubular secretion of Tamm-Horsfall protein in type 1 (insulin-dependent) diabetes mellitus using a simplified enzyme linked immunoassay

The relationship between glomerular and tubular dysfunction and metabolic control in type 1 diabetes was studied. To that end the urinary excretion rates of albumin and Tamm-Horsfall protein as well as HbA1c levels were measured in 58 patients with different degrees of diabetic nephropathy and in 76 apparently healthy subjects matched for sex and age. The urinary Tamm-Horsfall protein levels were measured by a simplified enzyme linked immunoassay. The intra- and interassay variations were 8.9% and 13.6%, respectively. The intraindividual variation was 41% and the sensitivity of the assay was 4 micrograms/l. The Tamm-Horsfall protein excretion rate was 42.1 x/2.0 micrograms/min (geometric mean x/tolerance factor) in the diabetic patients compared to 34 x/1.9 micrograms/min in the control subjects (NS). The diabetic patients had higher albumin excretion rate (38.5 x/7.3 micrograms/min) than the control subjects (4.7 x/2.3 micrograms/min; P less than 0.001). By using multivariate analysis of variance, HbA1c level was found to be the only independent variable associated with Tamm-Horsfall protein excretion rate in diabetic patients (r = -0.28; P = 0.04), while no relationship was found between Tamm-Horsfall protein excretion rate and age, age at onset and duration of diabetes, gender, serum creatinine, diuresis, urinary albumin excretion rate, systolic and diastolic blood pressure levels and antihypertensive treatment. The urinary albumin excretion rate was associated with diastolic blood pressure (r = 0.34; P = 0.02) but not with HbA1c levels when testing the above variables by multivariate analysis of variance. In conclusion, these results may indicate a lack of relationship between glomerular and tubular dysfunction. The former was influenced only by diastolic blood pressure levels and the latter only by the degree of metabolic control. However, the correlations were weak and do not provide any insight into what is actually responsible for glomerular and tubular dysfunction.

The influence of hypothermia on hypoglycemia-induced brain damage in the rat

The effects of hypothermia on hypoglycemic brain damage were studied in rats after a 30-min period of hypoglycemic coma, defined as cessation of spontaneous EEG activity. The rats were either normothermic (37 degrees C) or moderately hypothermic (33 degrees C). Morphological brain damage was evaluated after various periods of recovery. Hypothermic animals with halothane anesthesia never resumed spontaneous respiration, thus requiring artificial ventilation during recovery (maximally 8 h). In contrast, when isoflurane was used as the anesthetic agent, all animals survived and were examined after 1 week of recovery. There was a tendency towards gradually higher arterial plasma glucose levels during hypoglycemia with lower body temperature. The time period from insulin injection until isoelectric EEG appeared was gradually prolonged by hypothermia, and was shorter when isoflurane was used for anesthesia. Brain damage was examined within the neocortex, caudoputamen and hippocampus (CA1, subiculum and the tip of the dentate gyrus). Damage to neurons was found to be of two types, namely condensed dark purple neurons (pre-acidophilic) and shrunken bright red-staining neurons (acidophilic). In the neocortex, no clear influence of temperature on the degree of injury was seen. In the caudoputamen, the number of injured neurons clearly decreased at lower temperature (33 degrees C, P less than 0.001) when halothane was used, while no such difference was seen when isoflurane was used as the anesthetic agent. Likewise, a protective effect of hypothermia was seen in subiculum (P less than 0.01) when halothane, but not isoflurane was used.(ABSTRACT TRUNCATED AT 250 WORDS)

Association between urinary N-acetyl-beta-glucosaminidase and its isoenzyme patterns and microangiopathy in type 1 diabetes mellitus

Urinary N-acetyl-beta-glucosaminidase (NAG) and its isoenzymes (NAG A and NAG B) in samples from 87 type 1 diabetic patients and 40 apparently healthy reference subjects were studied with enzyme immunoassays. The diabetic patients had higher concentrations of urinary NAG than did the control subjects (P less than 0.01), but the isoenzyme pattern did not differ. There was a positive correlation between metabolic control (Hb A1c concentrations) and total NAG (P less than 0.01), NAG A (P less than 0.01), and NAG B (P less than 0.001). The diabetic patients were divided into three groups, depending on the degree of retinopathy. Subjects with severe forms of retinopathy did not have increased concentrations of urinary NAG unless they had concomitant nephropathy. The isoenzyme pattern was similar irrespective of degree of retinopathy or nephropathy. The results indicate that concentrations of urinary NAG are positively correlated to the degree of nephropathy, whereas there is no such correlation to the degree of retinopathy.

Association between urinary N-acetyl-beta-glucosaminidase and its isoenzyme patterns and microangiopathy in type 1 diabetes mellitus

Urinary N-acetyl-beta-glucosaminidase (NAG) and its isoenzymes (NAG A and NAG B) in samples from 87 type 1 diabetic patients and 40 apparently healthy reference subjects were studied with enzyme immunoassays. The diabetic patients had higher concentrations of urinary NAG than did the control subjects (P less than 0.01), but the isoenzyme pattern did not differ. There was a positive correlation between metabolic control (Hb A1c concentrations) and total NAG (P less than 0.01), NAG A (P less than 0.01), and NAG B (P less than 0.001). The diabetic patients were divided into three groups, depending on the degree of retinopathy. Subjects with severe forms of retinopathy did not have increased concentrations of urinary NAG unless they had concomitant nephropathy. The isoenzyme pattern was similar irrespective of degree of retinopathy or nephropathy. The results indicate that concentrations of urinary NAG are positively correlated to the degree of nephropathy, whereas there is no such correlation to the degree of retinopathy.

Acidosis-induced ischemic brain damage: are free radicals involved?

Substantial evidence exists that reactive oxygen species participate in the pathogenesis of brain damage following both sustained and transient cerebral ischemia, adversely affecting the vascular endothelium and contributing to the formation of edema. One likely triggering event for free radical damage is delocalization of protein-bound iron. The binding capacity for some iron-binding proteins is highly pH sensitive and, consequently, the release of iron is enhanced by acidosis. In this study, we explored whether enhanced acidosis during ischemia triggers the production of reactive oxygen species. To that end, enhanced acidosis was produced by inducing ischemia in hyperglycemic rats, with normoglycemic ones serving as controls. Production of H2O2, estimated from the decrease in catalase activity after 3-amino-1,2,4-triazole (AT) administration, was measured in the cerebral cortex, caudoputamen, hippocampus, and substantia nigra (SN) after 15 min of ischemia followed by 5, 15, and 45 min of recovery, respectively (in substantia nigra after 45 min of recovery only). Free iron in cerebrospinal fluid (CSF) was measured after ischemia and 45 min of recovery. Levels of total glutathione (GSH + GSSH) in cortex and hippocampus, and levels of alpha-tocopherol in cortex, were also measured after 15 min of ischemia followed by 5, 15, and 45 min of recovery. The results confirm previous findings that brief ischemia in normoglycemic animals does not measurably increase H2O2 production in AT-injected animals. Ischemia under hyperglycemic conditions likewise failed to induce increased H2O2 production. No difference in free iron in CSF was observed between animals subjected to ischemia under hyper- and normoglycemic conditions. The moderate decrease in total glutathione or alpha-tocopherol levels did not differ between normo- and hyperglycemic animals in any brain region or at any recovery time. Thus, the results failed to give positive evidence for free radical damage following brief periods of ischemia complicated by excessive acidosis. However, it is possible that free radical production is localized to a small subcellular compartment within the tissue, thereby escaping detection. Also, the results do not exclude the possibility that free radicals are pathogenetically important after ischemia of longer duration.

Increased levels of plasma homocysteine are associated with nephropathy, but not severe retinopathy in type 1 diabetes mellitus

The reactive vascular-injuring amino acid homocysteine was measured in plasma samples from 79 well-characterized type 1 diabetic patients and 46 control subjects. Patients with proliferative retinopathy had higher homocysteine levels (15.0 +/- 6.3 mumols l-1; mean +/- SD, p less than 0.001; n = 42) than those with progressive retinopathy during a two-year period (10.4 +/- 1.6 mumols l-1; n = 12), no or minimal retinopathy (10.7 +/- 4.3 mumols l-1; n = 25), and the control subjects (11.0 +/- 3.4 mumols l-1). Within the group of patients with proliferative retinopathy increased homocysteine levels were confined to those patients that had serum creatinine levels greater than 115 mumols l-1 and/or an albumin:creatinine clearance ratio greater than or equal to 0.02 x 10(-3) (17.0 +/- 5.9 mumols l-1; n = 23), whereas those with no or only minimal nephropathy had levels (12.1 +/- 5.5 mumols l-1; n = 18) that were not different from the control group. We conclude that neither type 1 diabetes mellitus nor diabetic retinopathy per se is associated with increased plasma homocysteine levels. In contrast, homocysteine accumulates, probably owing to reduced glomerular filtration, in diabetic patients with advanced nephropathy. This suggests that homocysteine might contribute to the accelerated development of macroangiopathy seen especially in this subgroup of diabetic patients.

The association between plasma beta-hexosaminidase and its isoenzyme patterns and retinopathy in type 1 diabetes mellitus

beta-Hexosaminidase and its isoenzyme patterns were investigated in plasma from patients with Type 1 diabetes mellitus. The patients were divided into three main groups matched for duration of diabetes: (a) proliferative retinopathy (b), progress of retinopathy within a two-year period (c) and with no background retinopathy. When all patients were compared to a reference group, a significant increase of plasma beta-hexosaminidase activity was found. Patients with proliferative retinopathy had significantly increased activity of plasma beta-hexosaminidase compared to the reference group but not compared to the other diabetic patients. The isoenzyme distribution was not different in any of the diabetic subgroups compared to the reference group. It was also shown that various degrees of diabetic nephropathy did not influence total plasma Hex or the isoenzyme pattern.

A study of exercise-induced microalbuminuria in type I (insulin-dependent) diabetes mellitus

Microalbuminuria is thought to be an important prognostic factor in diabetes mellitus. To study the influence of changes in blood pressure on the development of microalbuminuria during exercise, two exercise tests were carried out. A total of 32 insulin dependent diabetic men whose age at onset was less than 30 years, mean duration of diabetes 14 years (range 7 to 21) and mean age 29 years (range 21 to 40), and who did not have albuminuria (N-labstix negative) were studied. The diabetic patients were compared with a total of 29 age-matched male control subjects. Urinary albumin excretion was measured during two exercise tests: at a standardised workload (150 W) for 30 min, and at a standardised heart rate for 25 min. The diabetic patients had higher albumin excretion rates during both exercise tests compared with the control subjects. Blood pressure and heart rate during exercise were significantly higher in diabetic patients compared with control subjects in the standardised workload test. If the test was individualised to achieve the same standardised heart rate there was no significant difference in blood pressure between the diabetic patients and the control subjects. These results indicate that the diabetic kidneys were more sensitive than the healthy kidneys to similar degrees of haemodynamic stress induced by exercise.

Hydrogen peroxide production in ischaemic retina: influence of hyperglycaemia and postischaemic oxygen tension

Free radicals have recently been proposed to play a role in the development of diabetic retinopathy. Ischaemia and hyperglycaemia followed by recirculation have been suggested to initiate free radical production in other tissues and the aim of the present study was to examine whether this could also be the case in the retina. The present study showed retinal cell damage, as measured by pycnotic cells, to be more pronounced when ischaemia was combined with hyperglycaemia than when combined with normoglycaemia. As an indication of free radical production, catalase activity was measured, reflecting the production of hydrogen peroxide (H2O2). Small amounts of H2O2 were found to be generated in the normal retina, but did not increase during ischaemia and hyperglycaemia followed by recirculation. It thus seems, as if hyperglycaemia aggravates the harmful effects of ischaemia, but with the methods used, there does not seem to be any increase in free radical production (as measured by H2O2 production) in normal rat retina during ischaemic and hyperglycaemic conditions.

Free radical production and ischemic brain damage: influence of postischemic oxygen tension

It is now becoming increasingly clear that free radicals contribute to brain damage in several conditions, such as hyperoxia and trauma. It has been more difficult to prove that free radical production mediates ischemic brain damage, but it has often been suggested that it may be a major contributor to reperfusion damage, observed following transient ischemia. Recent results demonstrate that cerebral ischemia of long duration, particularly when followed by reperfusion, leads to enhanced production of partially reduced oxygen species, notably hydrogen peroxide (H2O2). It has also been suggested that postischemic hyperoxia, e.g. an increased oxygen tension during the recirculation period, adversely affects recovery following transient ischemia. Other data support the notion that brain damage caused by permanent ischemia (stroke) is significantly influenced by production of free radicals. The present study, however, fails to show that recirculation following brief periods of ischemia (15 min) leads to an enhanced H2O2 production, and that hyperoxia aggravates the ischemic damage. This study was undertaken to reveal whether variations in oxygen supply in the postischemic period following forebrain ischemia in rats affect free radical production and the brain damage incurred. To that end, rats ventilated on N2O/O2 (70:30) were subjected to 15 min of transient ischemia. Normoxic animals were ventilated with the N2O/O2 mixture, hyperoxic animals with 100% O2, and hypoxic ones with about 10% O2 (balance either N2O/N2 or N2) during the recirculation. At the end of this period, the animals were decapitated for assessment of H2O2 production with the aminotriazole/catalase method. This method is based on the notion that aminotriazole interacts with H2O2 to inactivate catalase; thus, the rate of inactivation of catalase in aminotriazole treated animals reflects H2O2 production. In a parallel series, animals ventilated with one of the three gas mixtures in the early recirculation period, respectively, were allowed to recover for 7 days, with subsequent perfusion-fixation of brain tissues and light microscopical evaluation of the brain damage. Animals given aminotriazole, whether rendered ischemic or not, showed a reduced tissue catalase activity, reflecting H2O2 production in the brain. Hyperoxic animals failed to show increased tissue H2O2 production, while hypoxic ones showed a tendency towards decreased production. However, all three groups (hypo, normo- and hyperoxic) had similar density and distribution of neuronal damage. These results suggest that although postischemic oxygen tensions may determine the rates of H2O2 production, variations in oxygen tensions do not influence the final brain damage incurred.(ABSTRACT TRUNCATED AT 400 WORDS)

Albuminuria and associated medical risk factors: a cross-sectional study in 451 type II (noninsulin-dependent) diabetic patients. Part 2

The association between urinary albumin concentration (UAC) in a morning urine sample and medical risk factors was evaluated in a cross-sectional study of 451 type II (noninsulin-dependent) diabetic patients. The following four groups of patients were created according to their urinary albumin levels: A) normal (less than 12.5 mg/L); B) high normal (12.5-30 mg/L); C) microalbuminuria, ie, incipient nephropathy (31-299 mg/L); and D) clinical nephropathy (greater than or equal to 300 mg/L). The patients with high normal levels had higher HbA1c and systolic blood pressure levels than patients with values within normal limits. The prevalence of incipient and clinical diabetic nephropathy was 20 and 7%, respectively. Incipient nephropathy was associated with higher blood pressures and body weights. Patients with clinical nephropathy had even further increases in these parameters, were older, and had longer duration of diabetes. In both groups of nephropathy, men were preponderant. Thirty six percent of all patients and 73% of patients with clinical nephropathy were treated for hypertension; 55% were treated with insulin. The insulin-treated patients had poorer metabolic control, but there were no differences in blood pressure or serum creatinine levels as compared with those of patients not receiving insulin treatment. The proportion of patients with severe retinopathy increased with the degree of albuminuria, although 22% of the patients with clinical nephropathy continued to be nonretinopathic.

Urine and serum levels of the carboxyterminal domain (NCl) of collagen IV in membranous glomerulonephritis and diabetic nephropathy

Serum and urinary concentrations of NCl, the non collagenous globular domain of collagen IV, were used as markers for turnover of basement membranes. NCl levels were studied in membranous glomerulonephritis and diabetic nephropathy. Thirteen patients with membranous glomerulonephritis and 8 insulin-dependent diabetic patients with diabetic nephropathy were compared to 16 apparently healthy control subjects. The patients with membranous glomerulonephritis had lower levels of NCl in serum and urine compared to the control subjects. In comparison, the patients with diabetic nephropathy had similar levels of NCl in serum and urine as the control subjects. Furthermore, among patients with membranous glomerulonephritis, those with hypertension had higher serum levels of NCl than those without, which may indicate that hemodynamic factors influence the basement membrane collagen metabolism. It is suggested that there are differences in basement membrane turnover in membranous glomerulonephritis and diabetic nephropathy although there are similarities in glomerular histopathological features. Other possible mechanism are discussed. Further studies are needed to confirm the suggested mechanism.

Albuminuria and associated medical risk factors: a cross-sectional study in 476 type I (insulin-dependent) diabetic patients. Part 1

Albumin concentration in a morning urine sample was analyzed in a cross-sectional study in 476 insulin-dependent diabetic patients. The following groups of patients were defined: A) normal urinary albumin (urine albumin less than 12.5 mg/L); B) high normal albuminuria (12.5-30 mg/L); C) microalbuminuria, ie, incipient nephropathy (31-299 mg/L); and D) clinical nephropathy (greater than or equal to 300 mg/L). The prevalences of incipient and clinical diabetic nephropathy were 24.8 and 14.4%, respectively. There were no differences in clinical parameters such as age, age at onset or duration of diabetes, blood pressure, serum creatinine, or HbA1c levels between groups A and B. The frequency of retinopathy in these groups was 55 and 50%, respectively. In group C, there were increases in age, duration of diabetes, blood pressure, serum creatinine, and HbA1c levels. The frequency of retinopathy was higher (80%), and more patients had severe forms (47%). In group D, there were further increases in all parameters and, in addition, younger age at onset of diabetes. The frequency of retinopathy was 97%, and severe forms of retinopathy were more common (86%). Seventeen percent of the patients were treated for hypertension. These patients were older, had longer duration of diabetes, and had higher levels of blood pressure, serum creatinine, and urinary albumin, as well as a younger age at onset of diabetes than patients not requiring antihypertensive treatment.

Urinary excretion of the carboxy terminal domain of type IV collagen is associated with kidney size and function in IDDM

We evaluated whether urinary excretion of the carboxy terminal domain (NC1) of Type IV collagen is associated with glomerular filtration rate and kidney size in Type I (insulin-dependent) diabetes mellitus (IDDM). Urinary excretion rate of NC1, glomerular filtration rate (GFR), and kidney size were measured in 16 men with Type I diabetes. Their mean age was 33.3 +/- 6.1 years with a duration of diabetes of 14.9 +/- 3.7 years (mean +/- SD). The urinary excretion rate of NC1 was higher in the diabetic patients than in 18 healthy control subjects. Urinary excretion of NC1 was associated with both kidney size, parenchymal width, and GFR (r = 0.73, p = 0.001; r = 0.63, p = 0.009; r = 0.53, p = 0.04, respectively). The exact relationship between these factors and basement membrane turnover/synthesis remains to be elucidated.

The importance of peripheral pulses, peripheral oedema and local pain for the outcome of diabetic foot ulcers

In a prospective study, peripheral pulses, claudication, peripheral oedema, and rest pain were evaluated in 314 sequentially presenting diabetic patients with foot ulcers. In the ulcerated limb pedal pulses were found to be present in 44% of the patients, peripheral oedema in 38%, and rest pain in 19%. Twelve per cent had claudication. Presence of pedal pulses was more common in patients whose ulcers underwent primary healing (56%) than in those who healed after amputation (23%) or died (25%, p less than 0.001). Eighty per cent of the patients with pedal pulses present underwent primary healing. However, 49% of patients with absence of pedal pulses also underwent primary healing and 12 patients developed gangrene despite presence of pedal pulses. Peripheral oedema was more common in patients who required amputation (58%) or died (55%) than in patients with primary healing (26%, p less than 0.001). A tentative predisposing factor was identified in 95% of the patients, the most common factors being neuropathy, congestive heart failure, and previous deep venous thrombosis. Rest pain was more common in patients who required amputation (48%) or died (23%) than in those with primary healing (7%; p less than 0.001). Only 50% of patients with gangrene had rest pain and of these patients, only one underwent primary healing. The presence of pedal pulses, oedema, and rest pain give valuable but imperfect information on the possible primary healing of foot ulcers in diabetic patients.

Neurophysiological changes during insulin-induced hypoglycaemia and in the recovery period following glucose infusion in type 1 (insulin-dependent) diabetes mellitus and in normal man

Hypoglycaemia (median venous blood glucose 1.8 mmol/l; range 1.6-2.3) was induced by an intravenous infusion of regular insulin in eight patients with Type 1 (insulin-dependent) diabetes mellitus (age 28.0 +/- 7.4 years; mean +/- SD, duration 15.5 +/- 5.1 years) and in 12 age-matched healthy male control subjects. Multi-channel frequency analysis of electroencephalogram (electrophysiologic brain mapping) and recording of P300 and somatosensory evoked potentials were performed before, during and immediately after the hypoglycaemic period. The hypoglycaemia produced a significant increase in low frequency electroencephalographic activity in both groups, most pronounced over anterior regions of the brain. The electroencephalographic activity was normalised immediately after the hypoglycaemic period. The patients with diabetes showed somewhat longer P300 latencies during the initial normoglycaemic examination. Hypoglycaemia caused a marked reduction of the P300 amplitude in both groups of subjects and the amplitude was not restored immediately after normalisation of blood glucose levels. The somatosensory cortical responses were not affected by hypoglycaemia. We conclude that hypoglycaemia results in impairment in cerebral function, as measured by neurophysiological techniques, which is not immediately normalised when blood glucose is restored to normal.

The influence of external precipitating factors and peripheral neuropathy on the development and outcome of diabetic foot ulcers

The influence of external precipitating factors and the presence of peripheral neuropathy on the development and outcome of foot ulcers were evaluated in 314 consecutive diabetic patients. All patients were treated by the same foot care team. Each patient was represented by one ulcer, and primary healing was defined as intact skin for at least six months. External precipitating factors were identifiable in 264 of 314 patients. The most common factors were ill fitting shoes/socks, acute mechanical trauma, stress ulcer, and paronychia. The highest primary healing rates were seen in lesions caused by paronychia (84%) and stress ulcer (76%). Clinical signs of sensory and muscular disturbances were seen in the majority of patients (96%). Sensory neuropathy, evaluated with a biothesiometer, was more common among patients who had had amputations or, died subsequently compared to those who healed. This study suggests that a majority of diabetic foot ulcers might have been prevented, since a precipitating external factor was identified in four of five patients, stressing the importance of preventive foot care.

Putative risk factors associated with retinopathy in patients with diabetes diagnosed at or after 30 years of age

In a cross-sectional study of diabetic patients diagnosed at or after 30 years, and with different stages of retinopathy, factors such as duration of diabetes, treatment mode, metabolic control, blood pressure, and clinical signs of nephropathy were examined. The different stages of retinopathy used were absence of retinopathy, simplex, and severe retinopathy. Patients with simplex and severe retinopathy were older than those without retinopathy (p less than 0.001, and p less than 0.01, respectively). They also had a longer duration of diabetes (p less than 0.001), and were more often treated with insulin (p less than 0.001) and in larger doses (p less than 0.001). Their glycosylated haemoglobin levels were higher (p less than 0.01). Their systolic blood pressure was higher (p less than 0.01), but the diastolic blood pressure did not differ, and the number of patients treated for hypertension was similar in all groups. Albumin clearance was higher (p less than 0.01 and p less than 0.001), as were urinary albumin levels (p less than 0.001). The only variables that distinguished patients with simplex from those with severe retinopathy were albumin clearance (p less than 0.01) and urinary albumin levels (p less than 0.05).

A new enzyme-linked immunosorbent assay for urine and serum concentrations of the carboxyterminal domain (NCl) of collagen. IV. Application in type I (insulin-dependent) diabetes

The major collagenous component of glomerular basement membrane (GBM) is collagen IV. Serum concentrations of the carboxyterminal end (NCl) of collagen IV have been proposed to be related to GBM turnover, which has been suspected to increase in diabetes mellitus. For the quantification of serum and urinary concentrations of NCl, a specific, sensitive enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies was developed. The detection limit of the assay was 30 micrograms/l at the 50% intercept of the standard curve. The intra- and interassay coefficients of variation were 6.2% and 13.9% for serum, respectively, and 11.9% and 39.7% for urine, respectively. The levels of NCl in serum and urine in 67 insulin-dependent diabetics and in 90 sex- and age-matched controls were compared. There were no differences in the serum concentrations of NCl between the diabetics and healthy controls. As a group, the diabetics had a higher urinary excretion of NCl than the controls (20.1 vs 12.5 ng/min, 2p less than 0.05). Furthermore, the results showed that the excretion of NCl in the urine was normal when the urinary albumin excretion rate (AER) was normal (less than 6.5 micrograms/min). The excretion was increased during the early stage of incipient diabetic nephropathy (AER 6.5-30 micrograms/min) and decreased to normal values with progression to clinical diabetic nephropathy (AER above 500 micrograms/min). Thus, it is suggested that an increased urinary excretion of NCl may be an early marker for incipient diabetic nephropathy.