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Biomedical subjects

G Caruso

Publications and source records attributed to G Caruso.

At least 235 records · Page 13Linked to original sources
PubMed1983

Glucose utilization in Type 1 (insulin-dependent) diabetes: Evidence for a defect not reversible by acute elevations of insulin.

It has long been assumed that replacement of insulin in insulin-deficient diabetic patients will normalise glucose utilization. In this study, glucose utilization was measured in nine long-standing, poorly controlled diabetic patients and five control subjects, matched for age (33 +/- 3 versus 33 +/- 2 years) and ponderal index (22.9 +/- 1.3 versus 21.7 +/- 1.0). Glucose uptake was measured during steady state insulinaemia in the diabetic patients and control subjects, at euglycaemia (5.5 +/- 0.5 versus 5.4 +/- 0.3 mmol/l, respectively) and moderate hyperglycaemia (11.8 +/- 0.9 versus 10.2 +/- 0.7 mmol/l, respectively). At euglycaemia with similar free insulin levels (50 +/- 19 versus 43 +/- 9 mU/l; p greater than 0.6), the diabetic patients utilized less glucose than the control subjects (27.8 +/- 4.2 versus 56.4 +/- 5.7 mumol.kg-1.min-1;.p less than 0.005). During hyperglycaemia, the diabetic patients utilized almost as much glucose as the control subjects did at euglycaemia (49.9 +/- 6.4 versus 56.4 +/- 5.7 mumol.kg-1.min-1, respectively). In the control subjects, a 1-mmol/l rise in glucose concentration (with insulin remaining constant) resulted in a 12.3 +/- 1.3 mumol.kg-1.min-1 rise in glucose utilization. In contrast, in the diabetic patients, a 1-mmol/l rise in blood glucose resulted in a rise in glucose utilization of only 3.8 +/- 0.8 mumol.kg-1.min-1 (p less than 0.001), in the presence of similar concentrations of plasma insulin. This defect of glucose utilization in Type1 diabetic patients could not be reversed by acutely raising insulin to 247 +/- 23 mU/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Insulin resistance in alloxan-diabetic dogs: evidence for reversal following insulin therapy.

Hepatic glucose production and peripheral glucose utilization were measured basally and during infusion of insulin (25 and 40 m U X kg-1 X h-1) in normal dogs and in insulin-deficient diabetic dogs, before and after a 10-14 day period of insulin treatment. Basal hepatic glucose production was significantly raised in the diabetic dogs (21.4 +/- 2.5 mumol X kg-1. min-1; p less than 0.005) compared with normal dogs (11.9 +/- 2.5 mumol X kg-1 X min-1) and fell by 20% in diabetic dogs following insulin treatment (17.4 +/- 3.0 mumol X kg-1 X min-1). However, in all groups, hepatic glucose production suppressed equally well during the low dose insulin infusions, suggesting that the raised hepatic glucose production of diabetes is due to insulin deficiency and not hepatic insulin resistance. In addition, a marked defect of glucose utilization was found in the diabetic dogs (25 +/- 5 mumol X kg-1 X min-1; p less than 0.001) compared with normal dogs (99 +/- 15 mumol X kg-1 X min-1) during matched hyperinsulinaemia and hyperglycaemia. This defect of glucose utilization, as defined by euglycaemic insulin dose-response curves employing insulin infusion rates between 40-600 mU X kg-1 X h-1, demonstrated a marked reduction of glucose disposal in diabetic dogs. The severity of the insulin resistance closely paralleled the degree of hyperglycaemia. In contrast, following 10-14 days of insulin treatment, an improvement of glucose disposal was seen in all diabetic dogs. It is concluded that insulin deficiency leads to (a) increased hepatic glucose production, and (b) the development of marked peripheral insulin resistance, which is reversed by insulin treatment.

Animals↗
PubMed1983

Median-ulnar nerve communications: electrophysiological demonstration of motor and sensory fibre cross-over.

In a 33-year-old female with carpal tunnel syndrome the presence of anomalous communications between median and ulnar nerves was electrophysiologically demonstrated in the forearm. Motor latencies from proximal and distal stimulation sites along the median nerve fibres to the abductor pollicis brevis were identical. Proximal latency "increased" after procaine infiltration of the ulnar nerve at the wrist. Normal latency to the abductor digiti minimi was obtained on stimulation of the median nerve at the elbow. Along the sensory fibres of the median nerve orthodromic conduction velocity was markedly slowed from digit III to the wrist and normal from the wrist to the elbow. On supramaximal stimulation of digit III a sensory response was also recorded from the ulnar nerve at the wrist. On stimulation of digit V a sensory potential was recorded from the median nerve at the elbow. This appears to be the first electrophysiological demonstration of an anomaly involving both the motor and sensory fibres of both the median and the ulnar nerves.

Adult↗
PubMed1983

The physiologic action of insulin on glucose uptake and its relevance to the interpretation of the metabolic clearance rate of glucose.

Glucose uptake (Ru) is dependent upon the concentrations of both glucose and insulin. The metabolic clearance rate of glucose (MCRG), has been used as an in vivo measure of insulin action, because it was said to be independent of the prevailing glucose concentration. The validity of this assumption has recently been challenged. In this study, the effect of insulin concentration on the rate of glucose uptake (Ru) and on the MCRG was studied during euglycemia (5.1 +/- 0.3 mmol/L) and moderate hyperglycemia (10.4 +/- 0.5 mmol/L) in 17 experiments on nine normal ambulant volunteers. Stable plasma insulin levels were maintained with fixed infusion rates of insulin (0-300 mU/kg/h) and somatostatin (7.5 micrograms/min). At low insulin concentrations (less than 5 microU/mL) the increase in glucose uptake in response to hyperglycemia was small (5.3 +/- 2.3 mumol/kg/min). In contrast, with insulin levels more than 25 microU/mL, there was a steep rise in glucose uptake with hyperglycemia (55 +/- 3 mumol/kg/min; range: 44-74 mumol/kg/min). The metabolic clearance rate of glucose fell by an average of 32% with hyperglycemia in the studies at the lowest insulin levels (2.2 +/- 0.6 v 1.5 +/- 0.1 mL/kg/min; 0.15 greater than P greater than 0.1). There was no change in the MCRG in the subjects studied at higher insulin levels. It is concluded that (1) low concentrations of insulin are essential for the increase in glucose disposal during hyperglycemia; and (2) provided insulin levels are more than 25 microU/mL and plasma glucose less than 11 mmol/L, MCRG is independent of the plasma glucose concentration and is therefore a valid measure of insulin-mediated glucose uptake.

Adult↗
PubMed1983

Friedreich's ataxia: electrophysiological and histological findings.

Electromyography was performed, and motor and sensory nerve conduction velocities were measured in 19 patients definitely affected by Friedreich's ataxia. Biopsy of the sural nerve was also performed in 9 patients. Most patients presented a moderate to severe loss of motor units, a significant increase in mean duration of motor unit potentials, and in the incidence of polyphasic potentials. Short-lasting spontaneous activity was rarely seen. Conduction velocity along the motor and sensory fibres of the median and tibial nerves was moderately slowed, while distal conduction time to muscle was significantly increased and the sensory orthodromically-evoked response markedly reduced. Intraoperative electrophysiological recordings obtained during biopsy of the sural nerve in 4 patients were consistent with the changes conventionally observed in the median, tibial and sural (6 patients) nerves. Quantitative histology revealed a reduced number of total myelinated fibres with a severe loss of large fibres, and a moderate loss of fibres of less than 7 microns in diameter. In teased nerve fibre preparations, the most evident abnormality consisted of fibres with uniformly short internodal length, while signs of remyelination were less prominent. Signs of active axonal degeneration were rarely observed in electron microscopy. Electrophysiological and histological findings were uniformly distributed, and the changes were neither related to the duration nor to the severity of the clinical condition.

Adolescent↗
PubMed1983

Biological behaviour of laryngeal adenoid cystic carcinoma. Therapeutic considerations.

Two cases of adenoid cystic carcinoma of the larynx are reported with a review of the world literature. This tumour, though capable of metastasizing via the blood stream to various organs (brain, lung, bone, etc.), seldom spreads to the cervical lymph nodes, usually by direct infiltration. Because of the biological behaviour of the neoplasm, radical neck dissection is not indicated.

Adult↗
PubMed1982

Validation of a practical in vivo insulin dose-response curve in man.

To adequately investigate the state of insulin resistance, an insulin dose-response curve should be constructed so that insulin sensitivity (right shift of dose-response curve) and insulin responsiveness (maximal response) can be determined. This paper describes and validates in man a practical in vivo insulin dose-response curve technique, using a modification of the euglycaemic clamp described by De Fronzo et al. Insulin action at steady state was expressed as metabolic clearance rate of glucose (MCRG) rather than overall rate of glucose disappearance (M or Rd). MCRG was chosen because at plasma insulin concentrations greater than 25 microunits/ml it was shown (n = 5) not to be altered by changes in blood glucose concentration (MCRG 379 +/- 23 and 408 +/- 19 ml/m2/min; at plasma glucose concentrations 5.4 +/- 0.3 and 10.2 +/- 0.7 respectively), whereas Rd was critically dependent on the prevailing blood glucose concentration (Rd 2007 +/- 128 and 4124 +/- 219 mumol m2/min respectively). MCRG was demonstrated to be stable over a 6 hr period (n = 8) and to be reproducible (n = 4). Insulin dose-response curves (MCRG Versus insulin concentration) were performed on two obese and seven normal weight individuals. The insulin dose-response curves were linearized, allowing accurate prediction of the maximal MCRG, as compared to the experimentally determined maximal response (r = 0.953 p less than 0.01). The use of this transformation obviates the need to employ very high insulin infusion rates to determine the maximal insulin response. In conclusion, the technique permits, in a single 6 hr study, a precise insulin dose-response curve to be constructed for accurately determining insulin sensitivity and responsiveness.

Adult↗
PubMed1982

Myocardial disarray. A critical review.

Myocardial disarray or disorganisation is at present a contentious topic, not least because its value as a clinical marker for hypertrophic cardiomyopathy has changed considerably over the years. Initially observed as one of the features of asymmetric septal hypertrophy, disarray has since been promoted as its pathognomonic histological feature, regarded by some observers as the morphological manifestation of a genetically transmitted myocardial defect. Recently, however, it has become evident that myocardial disarray is not limited to hypertrophic cardiomyopathy, but is encountered in hearts with both congenital and acquired conditions, and is also observed in normal hearts. The specificity of disarray for hypertrophic cardiomyopathy is thus seriously questioned. Latterly, it has been suggested that disarray, judged from through-and-through sections of the ventricular midseptum is a highly specific and sensitive marker of hypertrophic cardiomyopathy when considered in quantitative rather than qualitative fashion. The present study sets out to answer the question whether disarray could be the histological expression of the normal but intricate fibre architecture of the heart, a consideration also initiated by debatable definitions of normality and abnormality of myocardial histology. Gross fibre dissections in five normal hearts showed that many sites occurred in which disarray was a natural phenomenon. In five more hearts it was found that the plane of section of a tissue block might profoundly influence the histology. In fact, tissue cubicles sampled from different faces showed a change in histology in the vast majority. Thus the diagnostic significance of myocardial disarray as a marker of hypertrophic cardiomyopathy in the clinical setting almost vanishes; a change in orientation of a tissue section may actually turn "normality" into "disarray".

Adolescent↗
PubMed1982

Hemispheric functionality patterns between dextrals and sinistrals in tactile-visual tasks at lower or higher level of mental processes.

Two different patterns of unilateral tactile-visual recognition tasks with random shapes were administered to 64 subjects, 32 right-handed (16 males, 16 females) and 32 left-handed (16 males, 16 females). The main effects were found in the over-all performance: dextral subjects performed better than sinistral subjects; males performed better than females. On the task at a lower level of mental process dextral subjects performed better over-all than the sinistral subjects; however, neither group showed superiority of one hand over the other. On the task at a higher level of mental process performance of sinistral subjects improved to a level equivalent to that of the dextral subjects. Dextral subjects tended to perform better with their left hands, whereas the sinistral subjects scored equally with both hands. The findings are discussed in terms of quantitative and qualitative differences in patterns of hemispheric functionality between dextral and sinistral subjects, and the more specific cerebral activation for tasks at a higher level of mental process is hypothesized.

Adolescent↗
PubMed1981

Primary Small Cell ("Oat Cell") carcinoma of the larynx and hypopharynx.

The present paper is a clinico-pathological study of 8 cases of small cell("oat cell") carcinoma of the larynx and hypopharynx investigates at the Section of Pathology of the ENT Department of Padua University during the last 14 years (from January 1966 to December 1969). Besides a review of the world literature, several problems connected with terminology, histogenesis and pathologic patterns (microscopic, histochemical and ultrastructural) and examined, together with the differential diagnosis, clinical aspects and therapeutic approach. The association of small cell carcinoma with squamous cell carcinoma both in the larynx and hypopharynx is reported.

Adult↗