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Biomedical subjects

C Bellini

Publications and source records attributed to C Bellini.

123 records · Page 7Linked to original sources
PubMedDate not supplied

Use of a transient expression assay for the optimization of direct gene transfer into tobacco mesophyll protoplasts by electroporation.

Plasmid DNA was transfected into tobacco mesophyll protoplasts by electroporation. Transfection efficiency was estimated, using a transient expression assay based on the measurement of chloramphenicol transacetylase activity or by scoring colonies expressing resistance to paromomycin, an aminoglycoside related to kanamycin. Under conditions of cell survival superior to 50% after electroporation, transient expression signals and transformation efficiencies were found to be proportional. Factors affecting the efficiency of transformation were studied. A clear-cut optimum voltage (250-300 V/cm) was detected. Among various salts tested, potassium chloride was the best electrolyte. No improvement of electroporation efficiency was obtained by a heat-shock (45 degrees C/5 min) treatment prior to electroporation or by the presence of polyethylene glycol in the electroporation medium. The physiological state of plants used as the protoplast source significantly affected the transfection ability of the resulting protoplasts. These results are discussed and compared to previously published procedures.

Acetyltransferases↗
PubMedDate not supplied

Enteral nutrition in anorexia nervosa.

Biochemical and anthropometric data were collected in 9 subjects with anorexia nervosa before and after enteral nutrition by the nasogastric route. All subjects but one accepted the treatment which was stopped as soon as an adequate spontaneous food intake was resumed. Enteral nutrition caused a significant increase of mid-arm muscle circumference and of tricipital skinfold. Body weight gain was remarkable, averaging a rate of 8.22 kg/month. This value was not different from the levels attained by anorectic subjects put on total parenteral nutrition. Furthermore, a significant rise of some biochemical indexes, namely prealbumin and total iron binding capacity, was achieved. The most impressive drawbacks of enteral nutrition were occasional hypophosphatemia and moderate rise of serum aspartate and alanine aminotransferases. Both of these abnormalities were transient and apparently not associated with clinical disturbances.

Anorexia Nervosa↗
PubMedDate not supplied

[In vitro experimentation of a new model of radial flow bioreactor containing isolated hepatocytes].

Hepatocyte based artificial liver support systems are under investigation to support acute liver failure patients. The main purpose of such systems is to serve as a bridge to liver transplantation, or to promote spontaneous liver recovery. Limitation in mass-transfer capacity makes hollow-fiber bioreactors unsuited for long-term functioning of hybrid devices. We developed a novel radial-flow bioreactor in which the fluid perfuses the module from the center to the periphery, after having diffused through a space occupied by a three-dimensional structure filled with the hepatocytes. Five grams of freshly isolated porcine hepatocytes were seeded into uncoated, woven-non woven, hydrophilic polyester fabric, overlaid by two polyethersulfone membranes. Liver cells were perfused with 37 degrees C-warm, oxygenated, serum-free tissue culture medium, in which NH4Cl and Lidocaine were added at the final concentration of 1 mM and 60 micrograms/ml, respectively. Ammonium chloride removal, urea synthesis, monoethylglycinexylide (MEGX), pO2, pCO2, and pH were measured throughout the 14 day duration of the study. In a separate set of experiments, a scaled-up version of the radial flow bioreactor containing 150 grams of cells was perfused for 7 h with recirculating human plasma and MEGX production was monitored. During the 2 weeks of the study, an increasing production of urea was paralleled by constant ammonium removal. MEGX concentration after Lidocaine addition increased throughout the 14 days of perfusion with tissue culture medium, as well as after 7 hour perfusion with human plasma. Under transmission and scanning electron microscopy cells appeared attached to the polyester and one to each other, displaying ultrastructural features typical of functioning hepatocytes. Our study showed that liver cells were metabolically active when perfused into the radial-flow bioreactor. This configuration allowed close contact between media, or plasma, and cells at a physiological flow rate, by equalizing the concentration of the perfusing components, including O2, throughout the module. Our results suggest a potential use of this system for temporary extracorporeal liver support in acute hepatic failure patients.

Animals↗
PubMedDate not supplied

[The efficacy and tolerance of orally administered kallikrein in patients with essential arterial hypertension].

Since the reduced kallikrein excretion demonstrated in essential hypertension suggested the possibility of an impairment in the renal kallikrein-kinin system, we decided to evaluate the efficacy and safety of oral kallikrein administration (glandular kallikrein derived from porcine pancreas) in 30 essential hypertensive subjects (21 males, 9 females, age range 34-62 years). Twenty subjects took 150 IU kallikrein t.i.d. for eight days; during this period their sodium intake remained normal (120 mEq Na+/die). Ten subjects took placebo. After the trial period, urinary kallikrein in the active group increased from 0.9 +/- 0.4 U/24 h (normal value greater than 1.2 U/24 h) to 1.6 +/- 1 U/24 h (p less than 0.05); systolic and diastolic blood pressure decreased respectively from 154.6 +/- 13.8 mmHg to 140.3 +/- 12.5 mmHg (p less than 0.01) and from 92.5 +/- 1.5 mmHg to 86 +/- 3.9 mmHg (p less than 0.025); urinary sodium and potassium excretion increased respectively from 96.7 +/- 17 mEq/24 h to 119.1 +/- 32.3 mEq/24 h (p less than 0.05) and from 36.7 +/- 11 mEq/24 h to 43.5 +/- 12.8 mEq/24 h (p less than 0.05). One patient in the kallikrein group suffered a transient episode of gastric pain. No modifications of the parameters evaluated were observed in the placebo group. We conclude that kallikrein has a mild hypotensive effect in hypertensive subjects and is generally well-tolerated. Its antihypertensive effect is probably due to the sodiuretic action of the substance.

Administration, Oral↗
PubMedDate not supplied

[Correlations between circulation levels of natriuretic atrial peptide and urinary excretion of kallikrein in young normotensive and hypertensive subjects].

The relationships between atrial natriuretic peptide (ANP) and the renal sodium-modulating systems have not yet been completely examined. In particular, the relationships between ANP and the kinins system are almost unknown. We thus examined an extremely selected cohort of normotensive (n = 29, mean age 21 +/- 2 years) and hypertensive subjects (n = 51m mean age 21 +/- 2.9 years), both without hypertensive heredity. After 7 days under normal sodium intake (120 mEq of Na+/day), blood samples were taken in the morning on awaking, for radioimmunoassay of plasma levels of aldosterone, ANP and renin activity. Blood was again drawn after one active hour in orthostatism. We also evaluated urinary kallikrein excretion from urine collected over the previous 24 hours. Our results showed higher plasma levels of ANP in young hypertensives than in normotensives (statistical significance p less than 0.0025). Urinary excretion of kallikrein was markedly reduced (p less than 0.001) in the hypertensive group (0.46 +/- 0.3 U/24 h) compared to youths with normal blood pressure (0.79 +/- 0.24 U/24 h), in which a relationship between plasma ANP and urinary kallikrein was not evident; young hypertensives, on the other hand, showed an inverse correlation (r = -0.72; p less than 0.001). Finally, our investigation, aside from establishing the presence of high circulating ANP levels even at the initial phases of hypertension, points out a new possible means of feedback among sodium-modulating systems. The opposite relationship between ANP and urinary kallikrein excretion in young hypertensives could be attributed to reduced activity of the renal kinins system and a compensatory attempt on the part of ANP.

Adult↗
PubMedDate not supplied

[Oral administration of extracted kallikrein to patients with essential arterial hypertension].

Reduced kallikrein excretion has been demonstrated in essential hypertension, suggesting an impairment of the renal kallikrein-kinin system. Therefore, we evaluated the efficacy and safety of oral kallikrein administration (glandular kallikrein derived form porcine pancreas) in 20 essential hypertensives (14 males and 6 females) aged between 34 and 62 years. Kallikrein was administered (150 U.I. three times daily) over a period of eight days, under normal sodium intake (120 mEq of Na+/day). After the kallikrein administration period, urinary kallikrein resulted increased (from 0.9 +/- 0.4 U/24h, normal value greater than 1.2 U/24h, to 1.6 +/- 1 U/24h; p less than 0.05). Blood pressure decreased (systolic: from 154.6 +/- 13.8 mmHg to 140.3 +/- 12.5 mmHg; p less than 0.01--diastolic: from 92.5 +/- 1.5 mmHg to 86 +/- 3.9 mmHg; p less than 0.025), while urinary excretion of sodium (from 96.7 +/- 16 mEq/24h to 119.1 +/- 32.2 mEq/24h; p less than 0.05) and potassium (from 36.7 +/- 11 mEq/24h to 43.5 +/- 12.8 mEq/24h; p less than 0.05) increased after kallikrein administration. We observed only a transient episode of gastric pain. In conclusion, kallikrein administration has a mild hypotensive effect in hypertensive patients, and is generally well tolerated. The antihypertensive action is probably due to the natriuretic effect of kallikrein.

Administration, Oral↗
PubMedDate not supplied

[Changes in the atrial natriuretic factor and the renin-angiotensin-aldosterone axis induced by maximum exertion in subjects with a recent myocardial infarct].

To examine the effect of exercise-induced myocardial ischemia (EIMI) on atrial natriuretic factor (ANF), plasma renin activity (PRA) and aldosterone (PA), a maximal exercise test in 12 patients with recent acute myocardial infarction (AM) was performed. ANF, PRA and PA were measured by radioimmunoassay at baseline, peak-exercise and at 15 min after recovery. Four patients developed EIMI (group I) and 8 patients did not (group II). ANF increased in all patients from baseline to peak-exercise (27.7 +/- 9.5 pg/mL vs 92.7 +/- 26.7 pg/mL, p less than 0.0005) and it was still elevated 15 min after recovery. Baseline ANF was similar in both groups while at peak-exercise it was higher in group. I than in group II (112 +/- 15 pg/mL vs 82 +/- 26 pg/mL p less than 0.05). After 15 min of recovery, ANF was higher in group I than in group II (67 +/- 20 pg/mL vs 32 +/- 10 pg/mL, p less than 0.01), resulting higher than at baseline only in group I (p less than 0.05). PRA and PA also increased during exercise but their values rose more slowly and were the same in both groups. Thus, ANF, PRA and PA increase during exercise in patients after AMI, and EIMI is associated with higher ANF plasma levels.

Adult↗
PubMedDate not supplied

[Sodium-modulating hormones and the pressor response to sodium chloride in essential arterial hypertension].

Some predictive markers for NaCl sensitivity, related to the red blood cell membrane or to circulating proteins, have already been described in human essential hypertension. The present study was planned to investigate whether or not some hormones produced by the kidney or acting at the kidney level could be used as new markers for NaCl sensitivity. The study was conducted in 28 not previously treated outpatients affected by uncomplicated mild to moderate essential hypertension. After 15 days on a normal NaCl diet, plasma renin activity (PRA), plasma atrial natriuretic peptide (ANP), and the urinary excretion of active kallikrein were evaluated. The sensitivity of blood pressure to changes in NaCl intake was then assessed in all patients, according to a randomized double blind cross-over design. Each patient was assigned to a high (240 mmol of NaCl/day for 15 days) or low (40 mmol of NaCl/day for 15 days) NaCl intake. During the assessment of NaCl sensitivity, the double blindness was achieved by the use of capsules containing either NaCl or placebo. Fifteen patients (11 males and 4 females) resulted as NaCl-sensitive, while 13 patients (8 males and 5 females) were classified as NaCl-resistant. Our results indicate that PRA levels were significantly lower in the NaCl-sensitive group than in the NaCl-resistant one (0.108 +/- 0.05 ng/L/s vs 0.247 +/- 0.16 ng/L/s, p < 0.007), in the presence of raised levels of plasma ANP in NaCl-sensitive hypertensives (18.08 +/- 4.61 fmol/mL vs 12.45 +/- 3.77 fmol/mL, p < 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗