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Biomedical subjects

O Giampietro

Publications and source records attributed to O Giampietro.

At least 55 records · Page 3Linked to original sources
PubMed1994

Forearm blood flow reserve and cardiac and renal indexes of pressure load in normotensive and hypertensive individuals.

In response to hypertension, arterioles remodel their structure, the heart develops myocardial hypertrophy, and the kidney reduces creatinine clearance and increases albuminuria. To better understand the interrelations among the target organs involved in hypertension, we evaluated minimal forearm vascular resistances--a hemodynamic index of arteriolar structure derived from mean blood pressure and maximal postischemic forearm blood flow--the echocardiographic indexes of cardiac structure, and urinary albumin excretion and creatinine clearance in 29 male mild to moderate non-macroalbuminuric essential hypertensive patients on no drugs and 11 age- and sex-matched normotensive control subjects. Minimal forearm resistances were elevated in hypertensive patients and correlated with left ventricular mass, wall thickness, and mean arterial pressure. Patients with abnormal minimal forearm resistances (2 SD above normal) were characterized by higher pressure, greater wall thickness, lower creatinine clearance, and higher albumin excretion, suggesting that maximal forearm flow capacity does relate to the hemodynamic load exerted on both the kidney and heart. However, the correlation with cardiac structure and mean arterial pressure explained only part of the variability of minimal forearm resistances. Furthermore, no correlation among these parameters was found when hypertensive patients were evaluated separately from normotensive subjects, possibly because of heterogeneous factors active on arteriolar structure and unrelated to the pressor load. Overall, the data suggest that the development of abnormal minimal forearm resistances in the course of the hypertensive process is related to the pressor load, but its details need further understanding.

Adult↗
PubMed1993

Knowledge on diabetes and performance among health professionals in non-diabetological departments.

We tested the level of knowledge on diabetes and professional skills in a group of 60 non-diabetological health care professionals at the Policlinic of Pisa regarding the recognition and treatment of hypoglycaemia, the storage, mixing and administration of insulin, blood glucose stick monitoring, and the prevention and treatment of diabetic foot. The evaluation was carried out using a multiple-choice questionnaire and observation of the subjects, performance by means of pre-defined observation schedules, during the preparation and administration of a blend of rapid-intermediate insulin, the use of blood glucose sticks and the management of a simulated hypoglycaemic crisis. As regards hypoglycaemia, 90% of subjects did not give a correct definition, 88.3% were unaware of the existence of asymptomatic hypoglycaemia, and 96.6% did not give a complete answer as to the treatment of hypoglycaemia. For insulin, 51.7% did not know the standards for correct storage of insulin, 88.3% did not know the difference between "clear" and "opaque" insulins, and 91.7% ignored the required interval between administration of regular insulin and meals. For foot care, 45% admitted that the problems with diabetics' feet were frequently not controlled, and between 21.7% and 63.3% did not known the hygiene rules for feet. Assessment of the performance of the subjects using schedules revealed incorrect use of sticks and administration of insulin (80.2% mixed and 92.4% injected the insulin incorrectly). There is clearly a need for education of non-diabetological health professionals regarding the disease. This is supported by the health professionals themselves, 94.5% of whom wished to participate in a course on diabetes.

Blood Glucose↗
PubMed1993

How and how long to store urine samples before albumin radioimmunoassay: a practical response.

We used three study protocols to check the dependence of albumin stability, measured by an RIA, on different temperatures, durations, and materials (i.e., assay tubes) of urine storage. Albumin values obtained for samples stored in three types of assay tubes (glass, polystyrene, and polypropylene) throughout the 2 months of the first (prospective) protocol were superimposable. The 24-h storage of six urine samples at room temperature or at 4 degrees C, as well as 72-h storage at 4 degrees C, did not affect the albumin measurement by RIA. After 2 months of storage of these same six urine samples at -20 degrees C, there was still no albumin decrease. A significant albumin decrease occurred (a mean of approximately 5% per year, throughout the range of albumin concentrations tested) when samples stored at -20 degrees C were reassayed by RIA after > or = 2 years (second protocol, retrospective). Finally, 3 of 21 (14.3%) urine pools stored at -20 degrees C for various periods (4-21 months) showed a significant albumin loss after storage; the time of storage as well the decrement rates of these 3 pools differed from each other (third protocol, retrospective). Short- and medium-term (2-6 months) freezing of urine samples at -20 degrees C does not significantly affect the stability of immunoreactive albumin. For longer preservation periods, storage of urine samples at -70 degrees C may be preferable.

Albuminuria↗
PubMed1992

Which method for quantifying "microalbuminuria" in diabetics? Comparison of several immunological methods (immunoturbidimetric assay, immunonephelometric assay, radioimmunoassay and two semiquantitative tests) for measurement of albumin in urine.

We have compared the chemical and clinical characteristics of an immunonephelometric assay (INA), two immunoturbidimetric assays (ITA) and two semi-quantitative methods with those of a solid-phase radioimmunoassay (RIA) for measurement of urinary albumin (UA) concentration in 136 diabetic patients. INA and RIA had similar accuracy, and provided comparable results. However, RIA has slightly greater sensitivity than INA, which is easier and faster. Good agreement was also found between RIA and the two ITA methods, although one of these overestimated RIA values in the low-medium range (5-30 mg/l) of urinary albumin. ITA seems suitable for initial screening of albuminuria in diabetic patients but more sensitive procedures (such as RIA and INA) seem preferable for measurement of UA concentrations in the normal range. The two semi-quantitative methods showed high sensitivity but poor specificity, because of the large number of false positive results. About 50% of diabetic patients "positive" by these methods did not have microalbuminuria. The utility of these methods is questionable, because many samples from diabetic patients need to be reassayed by a more specific and sensitive assay such as the RIA, INA or ITA methods.

Albuminuria↗
PubMed1992

Automated measurement of lactate dehydrogenase, alkaline phosphatase and gamma-glutamyltransferase in urines: an alternative to the manual procedure.

A sensitive and precise automated assay of urinary lactate dehydrogenase (EC 1.1.1.27), alkaline phosphatase (EC 3.1.3.1) and gamma-glutamyltransferase (EC 2.3.2.2) is described. For this purpose, we used a BM/Hitachi System 704 model and reagents for automated analysis of serum enzymes from Boehringer Mannheim. However, the schedules of enzyme chemistry parameters recorded by the autoanalyzer and the spectrophotometric calibration are reprogrammed to meet requirements deriving from urine adoption and to optimize the enzyme assay in this unusual medium.

Alkaline Phosphatase↗
PubMed1992

More on effects of storage time and temperature on urinary enzymes: a 1-year study.

Results of our conclusive study on urinary enzyme stability during sample storage are reported. We measured alanine aminopeptidase (AAP) and N-acetyl-beta-D-glucosaminidase (NAG) in morning urines from 9 healthy normal subjects immediately after collection and throughout a 1-year storage at -70 and -20 degrees C. AAP proved to be quite stable at -70 degrees C (99.2% of the basal value at the end of the year). NAG is partially preserved (84.1% of the basal value) at -70 degrees C, but significantly decreased (50.4%) at -20 degrees C.

Acetylglucosaminidase↗
PubMed1992

Urinary cholinesterase activity is increased in insulin-dependent diabetics: further evidence of diabetic tubular dysfunction.

We measured the cholinesterase activity in morning urines from 63 insulin-dependent diabetics and 27 controls. The total esterase (TotE) activity (Ellman's method) has been divided into aliesterase (AliE), pseudocholinesterase and acetylcholinesterase by means of two inhibitors, eserine and quinidine. Diabetics were divided in 2 groups according to the urinary albumin/creatinine ratio (mg/mmol, < 2 in group 1, > 2 in group 2). The urinary cholinesterase behavior was correlated with that of a known tubular lysosomal hydrolase, N-acetyl-beta-D-glucosaminidase (NAG). Compared to normals, in addition to a significant increase in urinary NAG in diabetes (in group 2 more than in group 1), TotE and AliE were also significantly raised (+36% and 109% of the controls, in group 1 as much as in group 2).

Adolescent↗
PubMed1992

Endogenous digitalis-like factors in human milk.

We measured the concentration of endogenous digitalis-like factors (EDLFs) in milk or colostrum of women during nursing on different days after delivery. EDLF concentrations were assayed by a solid-phase RIA involving antidigoxin antibodies and by a radioreceptor assay (RRA) involving human placenta Na+/K(+)-ATPase. The mean (SD) EDLF concentrations as measured by RIA were 35.6 (19.4) ng of digoxin equivalents per liter in milk samples (n = 37) and 61.3 (12.5) ng/L in colostrum samples (n = 5); the mean EDLF concentration as measured by RRA in milk samples (n = 11) was 573 (717) ng/L (range 0-2098). EDLF concentration in milk is greater than circulating concentrations in healthy adults but is comparable with serum concentration in the third trimester of pregnancy. In milk and serum samples (n = 8) collected at the same time, heating and (or) extracting with Sep-Pak C18 cartridges before the RIA produced significantly different EDLF values from those in untreated serum (P less than 0.001) and milk (P = 0.035). EDLF in milk appeared to be not bound or weakly bound to milk protein, as indicated by the fact that boiling did not increase the digoxin-like immunoreactivity.

Blood Proteins↗
PubMed1991

How can storage time and temperature affect enzymic activities in urines?

We measured a tubular brush-border enzyme (alanine aminopeptidase, AAP) and a lysosomal hydrolase (N-acetyl-beta-D-glucosaminidase, NAG) in morning urines from 15 healthy normal subjects to check if different storage times and temperatures could modify enzyme concentrations. Short-term (24 h) storage time at room temperature or 4 degrees C does not affect AAP and NAG activities. Both enzymes are well preserved at -70 degrees C. AAP dramatically falls after 1 month at -20 degrees C, lowering to about 8% of the initial value after only 4 days of storage. On the contrary, NAG is well preserved at these storage conditions. Centrifugation has revealed not critical for measurement of these two enzymes.

Acetylglucosaminidase↗
PubMed1991

Effects of storage time and temperature on urinary enzymes.

We measured three renal tubular brush-border enzymes (lactate dehydrogenase, LDH, EC 1.1.1.27; gamma-glutamyltransferase, GGT, EC 2.3.2.2; and alkaline phosphatase, AP, EC 3.1.3.1) in morning urine samples from 48 healthy subjects to check whether different storage times and temperatures could modify enzyme concentrations. Short-term (24 h) storage time at room temperature or 4 degree C does not affect urinary enzyme activity. A few days of freezing, at -20 or -70 degrees C, dramatically lowers LDH and AP values; GGT is partially preserved only at -70 degrees C, if the sample has been previously centrifuged. Urinary enzymes investigated in this study are extremely labile at low temperatures.

Alkaline Phosphatase↗
PubMed1990

Exercise-induced proteinuria in well-trained athletes.

We studied the rate of urinary excretion of albumin, alpha 1-microglobulin (as an indicator of the renal tubular involvement), sodium, potassium, and creatinine in the basal state (overnight urine collection) and after physical exercise (training session) in 10 professional cyclists, to verify whether protein excretion is increased even in well-trained athletes after physical effort. In addition, we wanted to understand whether the origin of exercise-induced proteinuria was glomerular, tubular, or both. Compared with the basal state (overnight collection), exercise significantly (P less than 0.01) increased the excretion rate of albumin (4.2 +/- 2.6 micrograms/min vs 18.1 +/- 10.6 micrograms/min, mean +/- SD), Na, and K, and also the urinary volume. Creatinine output was not affected by exercise. The mean (+/- SD) overnight excretion rate of albumin by athletes was quite similar to that found for 91 healthy nonathletes at rest (4.6 +/- 2.7 micrograms/min). The mean exercise-related excretion of alpha 1-microglobulin by the athletes significantly exceeded the overnight value (6.6 vs 0.3 mg/L, P = 0.037). Our study indicates that (a) albuminuria furnishes the greater contribution to the increase in exercise-induced proteinuria; (b) the exercise proteinuria is both glomerular and tubular in origin, and is reversible; (c) the enhanced protein requirement of athletes may in part be due to the recurrent excretion of proteins in the urine after physical effort.

Adult↗
PubMed1990

Is the endogenous digitalis-like factor the link between hypertension and metabolic disorders as diabetes mellitus, obesity and acromegaly?

Endogenous factors cross-reacting with antidigoxin antibodies have been found in several tissues and body fluids of animals and humans, using commercially available digoxin radioimmunoassay or enzyme immunoassay methods. The chemical characteristics of these endogenous factors are, at present, unknown, although it has been suggested that they could be substances with low molecular weight. Experimental studies and theoretical considerations indicate that endogenous digitalis-like factors (DDLFs), in addition to the ability to react with antibodies, might also bind to the specific cellular receptor of the cardiac glycosides and thus inhibit the membrane Na+/K(+)-ATPase (sodium pump). Therefore, EDLF can be an endogenous modulator of the membrane sodium-potassium pump and several authors have suggested that EDLF could play a role in the regulation of fluids and electrolytes, muscular tone of myocardial and also in the pathogenesis of arterial hypertension. In this review, the authors discuss the hypothesis that, in metabolic diseases such as diabetes mellitus, obesity and acromegaly, the sodium retention and volume expansion, possibly due to exaggerated sodium intake, and/or exogenously induced peripheral hyperinsulinemia and high levels of growth hormone, could trigger a sustained release of EDLF, which in turn increases the blood pressure.

Acromegaly↗
PubMed1989

Metabolic effects of three new low-dose pills: a six-month experience.

We evaluated the effects on glucose and lipid metabolism in 57 healthy volunteers randomly assigned to one of three low-dose oral contraceptives: two monophasic (desogestrel + ethinylestradiol, EE, and cyproterone acetate + EE) and one triphasic (gestodene + EE) contraceptives. Glucose and insulin responses during OGTT were slightly affected by the cyproterone pill. The insulin area/glucose area ratio and HbA1c level were unchanged in all women. No preparation affected total and LDL-cholesterol levels. Triglycerides rose in all groups, while HDL-CH did only in women taking the two monophasic pills. The three low-dose pills assessed in this study have negligible effects on glucose and lipid metabolism.

Adult↗
PubMed1989

[Effects of low-dose oral contraceptives on sugar metabolism].

The effects on carbohydrate metabolism by four low-dose oral contraceptives were evaluated in four low-dose oral contraceptives were evaluated-66 young women randomly divided in four groups. In the various preparations there were a different dosage of estrogen (ethinylestradiol) together different doses and types of progestogen (desogestrel, gestodene, cyproterone acetate). After six months of treatment, in all groups a slight increase of glycemic and insulinemic responses during OGTT was observed; the significance was achieved with the preparation containing cyproterone acetate alone. Glycated hemoglobin did not change. Our results suggest that these new low-dose oral contraceptives induced negligible metabolic side effects.

Adolescent↗