Correlations among autonomic, sensory, and motor neural function tests in untreated non-insulin-dependent diabetic individuals.

A well-defined group of untreated non-insulin-dependent (NIDD) subjects were evaluated to determine whether involvement of neural function measurements is generalized and symmetrical and to compare the autonomic, sensory, and motor neural measurements. After age adjustment, the sensory and motor neural function measurements were significantly slower in the diabetic group than in normal subjects (P less than 0.01). Similarly, the autonomic nervous system function measurements were also abnormal in the NIDD group (P less than 0.01). Further analysis revealed that each of the specific measurements--median motor nerve conduction velocity (NCV,P less than 0.005), peroneal motor NCV (P less than 0.005), median sensory NCV (P less than 0.005), dark-adapted pupil size after muscarinic blockade (P less than 0.02), pupillary latency time (P less than 0.02), and RR-variation after beta adrenergic blockade (P less than 0.001)--was significantly less by analysis of covariance after age adjustment in the NIDD group than in normal subjects. Thus, there was evidence of motor and sensory neural impairment in the upper and lower extremities as well as evidence of impairment of the reflex arcs involving the parasympathetic nerves to the heart and eye and the sympathetic nerves to the iris. Further analysis revealed that right and left NCV were correlated (P less than 0.01), as were the median motor and median sensory NCV (P less than 0.01), the median motor and peroneal motor NCV (P less than 0.001), and the peroneal motor and median sensory NCV (P less than 0.001). Thus, there was evidence of symmetrical upper and lower limb, as well as motor and sensory proportional involvement of large nerve fiber NCV in this group of NIDD subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensory perception threshold measurement: an evaluation of semiobjective testing devices.

Five semiobjective devices for testing sensory perception thresholds were concomitantly used on 36 normal subjects to determine normal threshold values, intersubject variability, and their correlation with age. The five devices include the Semmes-Weinstein monofilament (touch); three-point esthesiometer (two-point discrimination); Pfizer thermal tester (temperature); biothesiometer (vibration); and Optacon tactile tester (vibration). Each subject was tested at 12 upper extremity (UE) and ten lower extremity (LE) sites. The threshold was determined by the two-alternative forced choice method. Results showed that the mean threshold for each sensory perception modality in the UE sites was significantly lower than in the LE sites. The means of distally located sites for two-point discrimination and vibration thresholds were significantly lower than the means of the proximal sites in the UE. In the LE, touch perception threshold was significantly higher distally than proximally. Distally located nerves (median and ulnar) showed lower mean threshold values than proximally located nerves for two-point discrimination. There were also similar findings for the other sensory modalities in the UE and LE. The mean threshold of dermatomes showed significant variation across the trials for two-point discrimination and vibration sensation. Distally located dermatomes showed lower threshold values than those located proximally. The means of most sites tested for each sensory modality (except vibration tested by the Optacon) showed correlation with age. There was no difference in threshold values between men and women for any sensory modality. The mean values of standard deviation were provided for each peripheral sensory nerve and dermatome.(ABSTRACT TRUNCATED AT 250 WORDS)

Disproportionate elevation of immunoreactive proinsulin in type 2 (non-insulin-dependent) diabetes mellitus and in experimental insulin resistance.

In this study, we found that the ratio of proinsulin to total immunoreactive insulin was much higher in 22 patients with Type 2 (non-insulin-dependent) diabetes mellitus than in 28 non-diabetic control subjects of similar age and adiposity (32 +/- 3 vs 15 +/- 1%, p less than 0.001). In addition, the arginine-induced acute proinsulin response to total immunoreactive insulin response ratio was greater in diabetic patients (n = 10) than in control subjects (n = 9) (8 +/- 2 vs 2 +/- 0.5%, p = 0.009), suggesting that increased islet secretion per se accounted for the increased ratio of proinsulin to immunoreactive insulin. One explanation for these findings is that increased demand for insulin in the presence of islet dysfunction leads to a greater proportion of proinsulin secreted from the B cell. We tested this hypothesis by comparing proinsulin secretion before and during dexamethasone-induced insulin resistance in diabetic patients and control subjects. Dexamethasone treatment (6 mg/day for 3 days) raised the proinsulin to immunoreactive insulin ratio in control subjects from 13 +/- 2 to 21 +/- 2% (p less than 0.0001) and in diabetic patients from 29 +/- 5 to 52 +/- 7% (p less than 0.001). Dexamethasone also raised the ratio of the acute proinsulin response to the acute immunoreactive insulin response in control subjects from 2 +/- 0.5 to 5 +/- 2% (p = 0.01) and in diabetic patients from 8 +/- 2 to 14 +/- 4% (p = NS), suggesting that the dexamethasone-induced increment in the basal ratio of proinsulin to immunoreactive insulin was also due to increased secretion.(ABSTRACT TRUNCATED AT 250 WORDS)