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Biomedical subjects

C A Robinson

Publications and source records attributed to C A Robinson.

At least 19 recordsLinked to original sources
PubMed1992

Microalbuminuria associated with diabetic neuropathy.

OBJECTIVE: To test the hypothesis that microalbuminuria may show an independent statistical association with diabetic neuropathy. RESEARCH DESIGN AND METHODS: An observational study of a prospectively identified cohort was conducted at the University Medical Center. The cohort consisted of 78 consecutive diabetic patients who fulfilled the criteria of having diabetes for greater than 10 yr, a normal serum creatinine, urine negative for macroalbuminuria by a commonly used dipstick method, a blood glucose less than 13.8 mM (less than 250 mg/dl), and an HbA1 less than 11% (normal range 5.5-8.5%). Medical record review established the presence of chronic complications of diabetes. Urine albumin level was measured by radioimmunoassay. Albumin concn greater than or equal to 15 mg/L was used as a cutoff value for microalbuminuria. RESULTS: Twenty-five of 78 patients (32%) showed microalbuminuria. Of these, 51% had neuropathy, 39% had retinopathy, 35% arterial hypertension, 17% peripheral vascular disease, and 15% ischemic heart disease. After adjusting for age, sex, and type and duration of diabetes, diabetic neuropathy and hypertension showed a significant association with microalbuminuria. After adjusting for other diabetic complications, diabetic neuropathy showed a significant association with microalbuminuria. CONCLUSIONS: Microalbuminuria is independently associated with diabetic neuropathy. This association lends support to the theory of a vascular etiology for diabetic distal symmetrical neuropathy.

Albuminuria↗
PubMed1991

Acute tolerance in morphine analgesia: continuous infusion and single injection in rats.

This study aimed to determine whether the decline of the analgesic effect of morphine with a continuous infusion or that after a single injection correlates with the changes in brain concentration of morphine. The analgesic effect of morphine and its brain and serum concentrations were determined with a continuous 8-h infusion at a constant rate and after a single subcutaneous injection of the agent. The analgesic effect was determined by measuring the threshold of motor response to noxious stimulation. Brain and serum concentrations of morphine were detected by radioimmunoassay with the use of 125I-labeled morphine. With the constant-rate (4 mg.kg-1.h-1, intravenous) morphine infusion, the peak of analgesia could not be maintained: the increase in the pain threshold at 2 h was 1,003 g and at 8h was 286 g (a decrease in analgesia by 72%, P less than 0.0002). At the same time, the brain morphine concentration tended to increase, to 278 ng/g at 2 h and 329 ng/g at 8 h. After the single morphine injection (6 mg/kg, subcutaneous), recovery from analgesia occurred at a much faster rate than did the decrease in morphine brain concentration; the decrease in pain threshold was 79% at 90 vs. 30 min after the injection (P less than 0.0001), and the corresponding decrease in brain concentration was 28% (NS). The absence of correlation between analgesia and morphine brain concentration both with the constant-rate morphine infusion and after the single injection suggests the development of acute tolerance, which is pharmacodynamic in nature.

Analgesia↗
PubMed1991

Acute tolerance to the hypnotic effect of morphine in rats.

To demonstrate the development of acute tolerance to the hypnotic effects of morphine, loss and recovery of the righting reflex with a constant-rate morphine infusion was studied in rats. In one group of animals, brain and serum concentrations of morphine were detected (radioimmunoassay) at the time of loss of the righting reflex, and in another group, at the time of the reflex recovery. The morphine infusion at a constant rate of 14 mg.kg-1.h-1 caused a loss of the righting reflex in all animals that was achieved by 2.5 h. However, this level of response could not be maintained, and at 5 h it began to decline. All animals recovered the righting reflex by the ninth hour, despite the continuing morphine infusion. The morphine brain and serum levels at the times of loss and recovery of the righting reflex were not different. The results suggest a development of acute tolerance to the hypnotic effect of morphine, which is determined primarily by pharmacodynamic mechanisms.

Animals↗
PubMed1990

Transfer of human systemic lupus erythematosus in severe combined immunodeficient (SCID) mice.

To study the role of peripheral blood leukocytes (PBL) in the pathogenesis of human systemic lupus erythematosus (SLE), we transferred PBL from 5 SLE patients into 15 severe combined immunodeficiency (SCID) mice. Such reconstituted mice showed long-term presence of auto-antibodies characteristic of the donor in their sera, as well as human immunoglobulin deposition, and in some cases mouse C3, in the renal glomeruli. SCID mice repopulated with PBLs from normal donors do not develop serologic abnormalities or immunodeposits. It is concluded that human SLE serology and some associated renal changes can be reproduced solely by PBL transferred from afflicted patients, and that SCID-human-SLE mice may serve as an in vivo laboratory model for the study of human SLE.

Animals↗
PubMed1990

Screening for slight albuminuria: a comparison of selected commercially available methods.

Slight albuminuria predicts clinically significant nephropathy in patients with insulin-dependent diabetes mellitus (IDDM) and early death in patients with non-insulin-dependent diabetes mellitus (NIDDM). This study compares four commercially available methods for measuring low concentrations of urinary albumin. We tested random spot urine specimens from 50 nondiabetic volunteers and 100 diabetic patients. This specimen was chosen to simplify collection in an outpatient setting. Two screening methods were evaluated for their ability to detect urinary albumin in the range of 15 to 200 mg/L. Sensitivity and specificity were 100% and 54.7%, respectively, for the Ames Micro-Bumintest; and 95.5% and 91.5%, respectively, for the Sclavo Albumin Screen. The high number of false-positive results made the Micro-Bumintest unacceptable. The Albumin Screen yielded fewer false-positive results, but also produced some false-negatives. Two quantitative methods, a radioimmunoassay (RIA) and a turbidimetric assay (the SPQ Microalbumin), yielded results that agreed well with each other.

Albuminuria↗
PubMed1990

Analysis of 8-methoxypsoralen by high-performance liquid chromatography.

We report a simple and rapid procedure for assaying 8-methoxypsoralen (8-MOP) in plasma by high-performance liquid chromatography (HPLC). The standard curve for the assay is linear for 8-MOP from 15 to 500 micrograms/L (y = 0.002x-0.01, r = 0.99) with a lower limit of detection of 1.5 micrograms/L. Intra-assay precision (CV) was 6.0% at the 100 micrograms/L concentration and 10.0% at 50 micrograms/L (n = 30 each). Interassay precision was 6.4% at 100 micrograms/L and 7.0% at 50 micrograms/L (n = 50 each). Extraction recovery of 8-MOP was 98%. Common antiarrhythmics, sedatives, and hypnotics were found not to interfere.

5-Methoxypsoralen↗
PubMed1979

Computed tomographic evaluation of pear-shaped bladder.

Computed tomography (CT) was used to distinguish between pelvic lipomatosis and idiopathic inferior vena caval thrombosis as a cause of a pear-shaped bladder seen on intravenous urography. The findings on CT were explicit in explaining the patient's clinical problem.

Adult↗
PubMed1978

Histologic grading of Wilms' tumor as potential prognostic factor: results of a retrospective study of 26 patients.

A histologic grading system based on tumor differentiation was applied in a retrospective study of 26 patients with Wilms' tumor to determine if it might provide an index to prognosis. The results were compared to those obtained by applying a histologic classification based on the presence or absence of individual histologic structures to the same tumors. Low grade tumors with predominance of differentiated structures--glomeruli and tubules--were associated with a better cure rate than high grade tumors composed mainly of undifferentiated spindle elements. The presence of undifferentiated large cells correlated with poor cure rate. The findings suggest that histologic grading may be valid as a prognostic factor in Wilms' tumor.

Adolescent↗
PubMed1978

Selective involvement of the first carpometacarpal joint in scleroderma.

Selective involvement of the first carpometacarpal joint is described in four women with scleroderma. Radiographic abnormalities at this site included osseous erosion, radial subluxation of the metacarpal base, and (in two patients) intraarticular calcification. Perlarticular osseous erosions were noted at adjacent locations in three patients. The cause of this distinctive wrist finding in scleroderma is unknown, but its similarity to alterations in other connective tissue diseases suggests that muscular and tendon imbalance may be important in producing bone erosion and subluxation at this articulation.

Aged↗
PubMed1978

Association of diffuse idiopathic skeletal hyperostosis (DISH) and calcification and ossification of the posterior longitudinal ligament.

Diffuse idiopathic skeletal hyperostosis (DISH) is a common ossifying diathesis in middle-aged and elderly patients characterized by bone proliferation along the anterior aspect of the spine and at extraspinal sites of ligament and tendon attachment to bone. Four patients with DISH revealed extensive calcification and ossification of the posterior longitudinal ligament in the cervical spine. Review of cervical spine radiographs in 74 additional patients with DISH demonstrated bony hyperostosis of the posterior aspect of the vertebrae in 41%, posterior spinal osteophytosis in 34%, and posterior longitudinal ligament calcification and ossification in 50%. These ligamentous findings, which have previously been described almost exclusively in Japanese people, appear to be an additional skeletal manifestation of DISH.

Aged↗
PubMed1978

Pitfalls of the alcohol dehydrogenase procedure for the emergency assay of alcohol: a case study of isopropanol overdose.

We describe a case of ethanol and isopropanol ingestion that resulted in coma. The concentration of ethanol and isopropanol was 0.90 and 1.65 g/liter in serum and 3.12 and 5.34 g/liter in gastric contents. With an enzymatic (alcohol dehydrogenase) method for ethanol determination we obtained erroneous analytical results. Because of partial cross reactivity with isopropanol, ethanol concentration was overestimated and total alcohol (i.e., the contribution of isopropanol) was underestimated. This was recognized by measuring serum osmolality. Differences between measured and calculated serum osmolality that are not accounted for by the serum ethanol concentration as determined by an enzymatic ethanol method must be further investigated by specific methods to see if other alcohols are present.

1-Propanol↗
PubMed1978

Simple method for estimating glycosylated hemoglobins, and its application to evaluation of diabetic patients.

Recent reports have suggested that determination of glycosylated hemoglobin may serve as a clinical aid for long-term blood glucose control in diabetes mellitus. We describe a simple procedure for measuring it by ion-exchange chromatography. Hemolysates were subjected to Bio-Rex 70 chromatographic separation on small columns. Percentages in the normal group ranged from 4.7 to 8.8% of total hemoglobin; the mean +/- standard error was 6.61 +/- 0.31%. Values in the diabetic group ranged from 6.9 to 17.4%; the mean was 10.83 +/- 0.34. Plasma glucose concentrations after fasting, plotted vs. the percent of glycosylated hemoglobin, revealed a linear relationship at normal or moderately high glucose concentrations. However, the values for glycosylated hemolgobin approached a plateau with grossly higher plasma glucose concentrations after fasting. Our results support the view that, due to its long half-life, the estimation of glycoylated hemoglobin reflects the integrated glucose concentrations to which the erythrocytes have been previously exposed.

Adult↗
PubMed1976

Evaluation of narcotic and narcotic antagonist interactions in primates.

Multiple and single drug interactions were studied in morphine-dependent monkeys whose dependency was maintained by self-infusion. Naloxone, naltrexone, and cyclazocine precipitated abstinence syndrome which the animals generally controlled with increased morphine intake. Methadone and L-alpha-acetylmethadol (LAAM) initially reduced, then increased, the morphine intake. Multiple interactions were studied using ethanol, seconal, diazepam, amphetamine, and diphenylhydantoin.

Animals↗