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Biomedical subjects

W C Stolov

Publications and source records attributed to W C Stolov.

At least 19 recordsLinked to original sources
PubMed1992

Dermatomal somatosensory evoked potentials in the diagnosis of lumbosacral spinal stenosis: comparison with imaging studies.

Dermatomal somatosensory evoked potentials (DSEPs) and computerized tomography/magnetic resonance (CT and/or MR) images were retrospectively analyzed to evaluate their relationship in the diagnosis of lumbosacral spinal stenosis (SS). Of 155 patients referred for DSEPs with a clinical suspicion of lumbosacral SS, 58 met the inclusion criteria. DSEP abnormality was defined as: (1) N1 latency absent or greater than 2.5 SD; (2) side-to-side latency difference greater than 2 SD; (3) amplitudes greater than 2 SD below the mean; or (4) amplitude ratio greater than 2 SD. Involvement of two or more DSEP levels by any of the above criteria was labeled multiple root disease (MRD). Involvement of one level was labeled single root disease (SRD). Images were reviewed independently by a neuroradiologist. Results revealed 54 subjects with SS by imaging; 42 had MRD and 8 had SRD by DSEPs. Sensitivity for MRD and SS was 78%, and for MRD plus SRD and SS was 93%.

Electromyography↗
PubMed1992

Height is an independent risk factor for neuropathy in diabetic men.

Height may increase the risk of diabetic polyneuropathy, but previous studies are inconclusive. Our purposes were to further examine the hypothesis that height (HT) is an independent risk factor for diabetic polyneuropathy and to determine which electrophysiologic measures are influenced by HT in diabetic subjects. We studied 170 Japanese American men (ages 43-73 years, mean 61) including: 69 diabetic men (mean HT 166 cm), 54 normal men (mean HT 167 cm), and 47 men with impaired glucose tolerance (IGT) (mean HT 164 cm), measuring 28 nerve conduction study (NCS) parameters. We used data from normal men in developing regression models to adjust NCS parameters for HT, age, and temperature. Factor analysis was employed to reduce the 28 NCS parameters to five physiologically meaningful factors, one of which, a factor representing median and peroneal sensory amplitudes, was significantly correlated with HT (r = -0.38, P = 0.0011) in diabetic men; taller subjects having smaller sensory nerve amplitudes. No significant correlation was found between this factor and body mass index. This factor had no correlation with HT in normal or IGT men. Our data do not confirm previous reports of associations between HT and slowed motor conduction velocities in diabetic subjects. This study does, however, support the hypothesis that HT is an independent risk factor for sensory polyneuropathy in diabetic subjects.

Body Height↗
PubMed1992

Factor analysis. A methodology for data reduction in nerve conduction studies.

Analyzing multiple nerve conduction study parameters individually is statistically problematic. The goal of this study was to develop a useful factor analysis scheme for assessment of nerve conduction study abnormalities in diabetic neuropathy. Hypotheses were: (1) factor analysis produces a few physiologically meaningful factors, (2) there are associations between factors and markers of diabetic severity and (3) clinical impressions are related to factor scores. We studied 165 Japanese-American men: 52 nondiabetic, 66 diabetic and 47 with impaired glucose tolerance. One author (W.C.S.) obtained 28 nerve conduction study parameters in all subjects and factor analysis extracted five factors from these parameters. These factors were related to conduction velocities (factor 1), distal ulnar function (factor 2), sensory amplitudes (factor 3), distal median function (factor 4) and distal peroneal function (factor 5); together, they explain 57% of the variability in the total data. Diabetic factor scores were significantly (P less than 0.05) below that of the controls and correlations with fasting blood sugar were significant at the P less than or equal to 0.001 level. Use of this technique promises to permit sensible analysis of large amounts of data in clinical studies of diabetic and other types of polyneuropathy.

Age Factors↗
PubMed1991

Effect of statistical methodology on normal limits in nerve conduction studies.

Mean +/- 2 standard deviations (SD), which relies on a Gaussian distribution, has traditionally been used to derive normal limits for nerve conduction studies. Our purpose was to examine skew in nerve conduction study (NCS) parameters, and to compare normal limits derived by several alternative methods. We examined 22 NCS parameters from 75 asymptomatic, nondiabetic men (controls). The coefficient of skewness (g1) was significantly positive (P less than 0.10, two-tailed test) in 5 of 8 amplitude and 6 of 8 latency measurements. Transformation reduced g1 in 19 of 22 parameters, and was optimal when g1 was closest to zero. For each measurement, ideal normal limits were defined as mean +/- 2 SD of the optimally transformed data of the control subjects. The percentage of 66 diabetic subjects classified as abnormal by the raw data, but normal by the ideal normal limits, was the positive misclassification rate; while the percentage considered normal by the raw data, but abnormal by the ideal normal limits, was the negative misclassification rate. Mean +/- 2 SD of the raw data produced up to 11% positive misclassifications and 12% negative misclassifications. When the range of observed values was used, up to 6% positive misclassifications and 13% negative misclassifications were found, while the 2.5 or 97.5 percentile values produced up to 10% positive misclassifications and 13% negative misclassifications. We conclude that analyses using the raw data to derive normal limits result in an unacceptable rate of misclassification. Normal limits should be derived from the mean +/- 2 SD of the optimally transformed data.

Aged↗
PubMed1991

Glucose intolerance and diabetic complications among Japanese-American women.

The prevalence of glucose intolerance and diabetic complications was determined in second-generation Japanese-American (Nisei) women and compared to previously obtained results in Nisei men. A volunteer study sample of 191 Nisei women 45-74 years old was enrolled from a study population of 1489 Nisei women born 1913-1942, raised and educated in the U.S., and residing in King County, Washington. The enrolled sample included 72 with normal glucose tolerance, 67 with impaired glucose tolerance (IGT), and 52 with non-insulin-dependent diabetes. A random sample was also drawn from the study population to form a reference sample of 157 women. Based upon observations in the reference and enrolled samples, an estimated 16% of Nisei women in the study population have diabetes and 40% IGT. These rates compare to 20% diabetes and 36% IGT previously estimated for Nisei men 45-74 years old. The prevalence of cardiovascular disease (hypertension, peripheral vascular disease, and/or coronary heart disease) was highest among diabetic women, lowest in those with normal glucose tolerance, and intermediate in women with IGT. In comparison to diabetic men, there was a significantly lower frequency of neuropathy, peripheral vascular disease, and coronary heart disease in diabetic women. However, hypertension occurred equally often in both. Thus Japanese-American men and women 45-74 yr old have a similar prevalence of glucose intolerance, although less severe in women, and complications, except for hypertension, are reduced in women.

Adult↗
PubMed1988

Electrodiagnosis of diabetic peripheral polyneuropathy. A multivariate analytic approach.

Traditional univariate comparisons of nerve conduction data against standard norms may produce conflicting estimates of the presence or absence of a diabetic neuropathy, depending upon the data obtained and the specific nerves sampled. Alternatively, a multivariate analytic approach, using discriminant functions, provides a useful single measure of the degree of neuropathy determined as a weighted combination of the available data. The weights are derived from the linear discriminant function, which maximizes statistical separation of diabetic and nondiabetic subject groups. In this study, 12 electrophysiologic attributes are used to generate a single discriminant function that clearly separates diabetic from nondiabetic subjects and is interpretable as a neuropathic index. Each individual's index of diabetic neuropathy (I) can be quantified as follows: (Formula: see text) where Ai is the original electrophysiologic attribute (i = 12), ai is the coefficient for each attribute that defines the discriminant function and C is a constant specific for that function. For the first time, the degree of diabetic neuropathy can thus be quantified for purposes of comparison and correlation with other quantifiable clinical/somatic measures of diabetes. The index allows for a higher percentage of type II diabetic patients to be classified as neuropathic than previously described and enables determination of degree of neuropathy is affected individuals by an interpolative method.

Analysis of Variance↗
PubMed1987

Prevalence of diabetes mellitus and impaired glucose tolerance among second-generation Japanese-American men.

We describe the initial findings from a multidisciplinary, epidemiologic study of diabetes mellitus conducted in a population of second-generation Japanese-American (Nisei) men born between 1910 and 1939 who reside in King County, Washington (n = 1746). From this study population, 487 volunteered, and 229 were enrolled to comprise the study sample. A random sample of Nisei men was also drawn from the population to develop a reference sample of 189 men. All subjects participated in a 75-g oral glucose tolerance test; the National Diabetes Data Group (NDDG) and World Health Organization (WHO) diagnostic criteria as well as a modification of the WHO criteria were used to classify individuals with normal glucose tolerance, impaired glucose tolerance (IGT), or diabetes. Within the study sample, 79 men were found to have normal glucose tolerance, 72 had IGT, and 78 had type II diabetes. The mean age of the study sample was 61.4 yr. Based on comparison of the study sample to the reference sample, the study sample was ascertained to be representative of Nisei men in King County. Extrapolating from our observations in the reference sample and in the study sample, we have estimated that approximately 56% of Nisei men in the study population have abnormal glucose tolerance. Much of this is undiagnosed because only approximately 13% of the reference sample of Nisei men reported a prior diagnosis of diabetes. Of the men who enrolled in the study as nondiabetic subjects, 11.1% had diabetes and 39.2% had IGT; i.e., 50.3% had previously unknown abnormalities in glucose tolerance. We estimate that approximately 20% of Nisei men have diabetes (both previously diagnosed and undiagnosed) and approximately 36% have IGT.

Adult↗
PubMed1987

Prevalence of complications among second-generation Japanese-American men with diabetes, impaired glucose tolerance, or normal glucose tolerance.

In a study sample of 229 second-generation Japanese-American (Nisei) men, 79 with normal glucose tolerance, 72 with impaired glucose tolerance (IGT), and 78 with non-insulin-dependent diabetes, we have determined prevalence rates for certain conditions (ischemic heart disease, peripheral vascular disease, hypertension, retinopathy, neuropathy, and nephropathy) associated with diabetes. All subjects participated in a 75-g oral glucose tolerance test. World Health Organization (WHO) diagnostic criteria and information from the subject's medical history and personal physician were used to classify the subjects. Retinopathy was observed only in diabetic men in the study sample (11.5% of diabetic men). Furthermore, it was observed only in men who were receiving drug treatment for diabetes--40.0% of insulin-treated and 17.2% of sulfonylurea-treated men. Electrophysiologic evidence of peripheral neuropathy was observed in 46.2% of diabetic men and in 4.0% of nondiabetic (normal and IGT) men. For diabetic men with fasting serum glucose greater than or equal to 140 mg/dl, 63.8% had peripheral neuropathy and 19.1% had retinopathy, whereas for diabetic men with fasting serum glucose less than 140 mg/dl, 19.4% had neuropathy and none had retinopathy. For diabetic men with a diabetes duration of greater than or equal to 10 yr, 72.7% had neuropathy and 31.8% had retinopathy; with a diabetes duration of 5-9 yr, 70.6% had neuropathy and 11.8% had retinopathy; and with a diabetes duration of less than 5 yr, 20.5% had neuropathy and none had retinopathy. Nephropathy was distinctly uncommon, and among the measurements of kidney function, only proteinuria was clearly abnormal with diabetes. Prevalence rates of hypertension, peripheral vascular disease, and ischemic heart disease were highest in Nisei men with diabetes, lowest in men with normal glucose tolerance, and intermediate in men with IGT.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1986

Somatosensory evoked potentials after removal of somatosensory cortex in man.

Somatosensory evoked potentials (SEPs) to median nerve, ulnar nerve, thumb, middle finger, and posterior tibial nerve stimulation were recorded in a patient with a discrete resection of part of the postcentral somatosensory cortex as a treatment for focal epilepsy. Comparison of the different stimulation sites confirmed electrophysiologically the restricted locus of the lesion. The results strongly suggest that the early negative component (N20) and subsequent components recorded postcentrally are of cortical origin and depend upon postcentral gyrus cytoarchitectonic areas 3, 2, and 1. Moreover, these postcentral SEPs are distinct from precentrally recorded activity.

Adult↗
PubMed1979

Action myoclonus following acute cerebral anoxia.

Action myoclonus secondary to posthypoxic encephalopathy is being seen increasingly with improved resuscitation techniques. A case report describes 5 specific physical and occupational therapeutic techniques for achieving independence in ambulation, transfers and self-care: (1) analysis and segmentation of complex motions into small steps; (2) controlled progression of training; (3) voluntary cessation of abnormal activity (pacing); (4) progressive densensitization to external stimuli; and (5) quantification of progress. Literature review suggests that posthypoxic action myoclonus is secondary to a loss of inhibitory synapses in the brainstem reticular formation due to low serotonin levels. The proposed therapeutic effect of clonazepam, the drug used in this patient, is decreased serotinin degredation. L-5-hydroxytryptamine, an investigative drug, is also therapeutic, for it stimulates increased serotonin production.

Acute Disease↗
PubMed1978

Paraplegia: succinylcholine-induced hyperkalemia and cardiac arrest.

The rapid development of hyperkalemia leading to cardiac arrest can occur in patients with spinal cord injuries and other conditions when succinylcholine is used during the induction of anesthesia. Three patients with thoracolumbar spinal cord injuries resulting in lower motor neuron lesions or lesions above the lower extremity motor units developed hyperkalemia followed by cardiac arrest after succinylcholine administration. The mechanism by which succinylcholine leads to hyperkalemia from denervated muscle is described and precautions to be taken are mentioned. Physicians caring for patients with denervated muscle due to spinal cord injuries should be aware of this danger and nondepolarizing muscle relaxants should be used instead of succinylcholine.

Adult↗
PubMed1978

Gastrocnemius muscle belly and tendon length in stroke patients and able-bodied persons.

Length changes of gastrocnemius muscle belly and tendon at different passive tensions and ranges of motion (ROM) were measured in 31 healthy persons and 15 hemiplegic patients with clinically demonstrated ankle joint plantar flexion (PF) contractures. Preliminary studies were done to obtain accurate determination of gastrocnemius muscle insertion and origin points on x-ray films, to calculate the magnification factor due to x-ray beam divergence and to measure the length changes in muscle belly by the use of a wire hook placed at the muscle-tendon junction. Our results revealed: (1) change in length at different passive tensions is in the muscle belly, not in the tendon, (2) in hemiplegic patients no statistical difference in elongational characteristics of affected gastrocnemius muscle bellies with clinically demonstrated ankle PF contractures and of the contralateral nonaffected muscle bellies, (3) spastic and flaccid gastrocnemius muscle bellies are not statistically different in respect to passive elongations, (4) gastrocnemius muscle bellies of both affected and nonaffected legs of hemiplegic patients were statistically different from the muscle bellies of healthy persons in regard to maximal ROM and maxinum muscle belly length changes, (5) there was approximately .5 mm change in the belly length for each degree of ankle ROM, (6) age is not a factor influencing passive elongation of muscle belly, (7) average muscle belly lengths were consistently shorter in hemiplegic muscles while their tendon lengths did not change. The enumerated findings suggest that the limitation of ankle ROM in spastic hemiplegic legs obtained by the standard clinical measurements technique represents a change in muscle belly rest length without a structural contracture of the muscle fibers.

Adult↗
PubMed1977

Muscle fiber number in immobilization atrophy.

Eight Sprague-Dawley rats 10 to 12 weeks of age had one limb immobilized by plaster in knee flexion and ankle plantar flexion for four weeks. The soleus muscles from the control and immobilized limbs were excised and frozen. The technique used insured that cross sections subsequently cut and stained would contain all the fibers extending from the origin to the insertion aponeuroses. The total number of muscle fibers per muscle was counted from 25 to 50 photomicrographs made for each muscle cross section. Paired comparisons of total muscle fibers in control and immobilized muscles revealed no significant differences. The total number of fibers in control and immobilized soleus muscles was 2812 +/- 521 and 2930 +/- 403, respectively. Therefore, muscle fiber loss does not occur in disuse atrophy produced by external immobilization as has been reported.

Animals↗
PubMed1976

Microscopic features and transient contraction of palpable bands in canine muscle.

Ten pairs of biopsies were excised from gracilis and semitendinosus muscles of 4 mongrel dogs. These were compared with the histological findings reported in painful spots and muscle hardenings of human muscles. Test biopsies sampled a palpable band. Paired control biopsies sampled a portion of the same muscle where it showed no palpable hardening. Processed sections were randomized and read blind. Sections stained with aqueous toluidine blue showed no convincing metachromasia. Sections stained with trichrome showed no proliferation of endomysial connective tissue. Test sections stained with hematoxylin and eosin showed no proliferation of nuclei and no increase in the number of central nuclei in muscle fibers compared to control sections. No convincing histological difference was found. During surgery under Nembutal anesthesia, rubbing palpation of the exposed muscle elicited a transient contraction of a bundle of muscle fibers several milli-meters in diameter. This corresponded in time and position to the palpable band in the dog muscle. The band-like hardness palpated in these canine muscles appears to be caused by a circumscribed transient muscular contraction rather than histologically demonstrable structural changes.

Animals↗
PubMed1976

Needle electromyography: its effect on serum creatine phosphokinase activity.

The effect of needle electromyography on serum creatine phosphokinase (CPK) levels has remained unclear despite the diagnostic implications. Serum CPK was serially assayed for changes before and after electromyography (EMG) in two healthy persons and ten persons having low back pain, while they remained at total bed rest. Mean curves showed a peak at 6 hours post-EMG and a return to baseline 48 hours post-EMG. The mean peak value was 1.5 times the baseline. Only one sample exceeded the normal range and it was from a patient with frank positive waves and fibrillation potentials. Correcting for dilution of CPK released, by body weight and for total trauma, by number of needle insertions did not modify the results. The time course and magnitude of elevation of CPK parallel those reported for post exercise changes but are much less than those reported to follow myocardial infarction. In the differential diagnosis of myopathies, care must be taken to ensure that the combination of needle electromyography, exercise, diurnal variation and active denervation does not lead to a "false-positive" elevation of CPK above the normal range. Needle electromyography by itself should not induce a false-positive CPK level in a normal person and no significant changes in CPK levels are likely to occur within two hours after the study.

Adolescent↗