Biomedical subjects

R Armentano

Publications and source records attributed to R Armentano.

29 records · Page 2Linked to original sources

PubMed1988

[Constrictive and stiffening effects of parasympathetic blockade on the pressure response of the aorta to angiotensin in the conscious dog ].

The elastic response of the thoracic aorta to increasing steps of angiotensin was studied in chronic instrumented conscious dogs with and without parasympathetic blockade by atropine. A pressure microtransducer and two ultrasonic crystals diametrically opposed and fixed in the adventitia enabled to determine the mean and systolic-diastolic changes of pressure (P) and diameter (D). By computing these measurements two representative indexes of dynamic elastic modulus in vivo were calculated; the elastic modulus of Peterson (Ep) Ep = delta P/D.D and the incremental elastic modulus (Ei) Ei = 0.75 EP/gamma, gamma being the ratio of the thickness to the external radius. A positive correlation (p less than 0.01) was obtained between pressure and diameter variations in the presence or absence of atropine but the slope of these relationship were lower with atropine than in controls. The slope of the positive correlations observed between Peterson and incremental elastic modulus and the increase in mean arterial pressure in response to angiotensin (p less than 0.01) was higher in the presence of atropine (p less than 0.05). These observations indicate that in response to angiotensin mediated high blood pressure, the cholinergic blockade of muscarinic receptors with atropine induce a contraction and increasing rigidity of the aorta.

Angiotensin II↗

PubMed1987

Inconsistency of the slope and the volume intercept of the end-systolic pressure-volume relationship as individual indexes of inotropic state in conscious dogs: presentation of an index combining both variables.

We tested the ability of the slope (Emax) and the volume intercept (Vo) of the end-systolic pressure-volume relationship (ESPVR) to indicate contractility changes in conscious dogs instrumented with sonomicrometers measuring left ventricular diameter in three orthogonal axes and a left ventricular pressure microtransducer. ESPVRs were generated by inferior vena caval occlusion under control conditions (C1 and C2) and during enhanced (I+) and depressed (I-) inotropic states achieved by infusion of dobutamine and injection of propranolol, respectively. No significant difference between the first control (C1) and I+ or between the second control (C2) and I- were found for either Emax (C1, 5.31 +/- 1.68 mm Hg/ml, mean +/- SD; I+, 5.37 +/- 1.44; C2, 5.20 +/- 1.62; I-, 4.18 +/- 1.32) or Vo (C1, 10.3 +/- 9.6 ml; I+, 7.3 +/- 9.1; C2, 9.9 +/- 9.0; I-, 12.7 +/- 12.5), despite significant changes in other indexes of contractility. Comparison of changes in Emax in individual animals in response to I+ and I- revealed that 63% were nonsignificant, 28% were significant and expected, and 9% were significant and paradoxical. Within defined volume limits and irrespective of individual changes in Emax and Vo, in all animals I+ shifted the ESPVR above and to the left of C1 and I- shifted the ESPVR below and to the right of C2. We thus integrated the changes in Emax and Vo by measuring the area beneath each ESPVR between defined limits of end-systolic volume. The values for area were: C1, 612 +/- 150 mm Hg.ml; I+, 745 +/- 191 (p less than .001); C2, 520 +/- 198; I-, 420 +/- 139 (p less than .001). We conclude that (1) neither Emax nor Vo are individually reliable indexes of changed contractility, and (2) the area beneath the ESPVR between defined end-systolic volume limits is a consistent indicator of variations in inotropic state.

Animals↗

PubMed1987

[Study of the visco-elastic response of the aortic wall to angiotensin and noradrenaline in the conscious dog by analysis of the instantaneous pressure-diameter relation in the descending aorta].

The viscoelastic behaviour of the aorta has been studied in 7 adult non-anesthesized mongrel dogs, chronically instrumented with a microtransducer pressure (Konigsberg P7) implanted inside the aortic lumen, and 2 ultrasonic crystals diametrically opposed and fixed in the adventitia of the thoracic aorta. Pressure and diameter were analysed in terms of mean values and of systolic diastolic variations, enabling to calculate the elastic modulus of Peterson. After recovery from surgery, and under autonomic blockade by atropine and propranolol, perfusions of angiotensin and norepinephrine were performed at incremental steps of doses. In individual dogs, instantaneous pressure-diameter relationships were formed by the different pressure diameter hysteris loops obtained at each dose of the same drug; the relationships obtained with the two drugs were curvilinear and were mixed at lower pressure ranges, but at highest levels of pressures it was found, that comparatively to angiotensin curve, that of norepinephrine had shifted toward lower diameter. The percent increase in mean diameter from baseline obtained at each dose of the same drug, was positively correlated to the corresponding per cent increase in mean pressure, with angiotensin (r = 0.83 P less than 0.001), and for norepinephrine (r = 0.82 P less than 0.001), but the slope of the relation was lower with angiotensin (22.3 +/- 3.2) than with norepinephrine (12.8 +/- 1.9) (P less than 0.001); likewise, the elastic modulus, for each dose of a same drug, was positively correlated to the corresponding mean pressure for angiotensin (r = 0.53 P less than 0.01), norepinephrine (r = 0.69 P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗

PubMed1986

Real-time pressure-volume diagrams for the evaluation of ventricular function.

Using three intraventricular diameter signals obtained from ultrasonic distance gauges and applying the general ellipsoid model to the left ventricle, it was possible to obtain the left ventricular volume signal. Implanting a miniature transducer in the left ventricle the pressure signal was attained. With these two signals the pressure-volume diagrams were constructed on line, and ventricular function during load manoeuvres could be studied from them. Because the whole process was done on line, using a microcomputer, the performance of the left ventricle to load manoeuvres in different conditions could be seen instantly.

Animals↗

PubMed1986

Correlation of cineangiographic and pathology findings in coronary artery disease.

In order to correlate the percent of coronary lumen reduction measured by cineangiography and by pathology, we reviewed the coronary trees of 12 patients who died of coronary heart disease. The 36 arterial segments were divided in two groups: group I showing a good correlation in its 24 segments (less than 15% difference between both methods, r = 0.90), and group II (12 segments) with a poor correlation. No significant differences were found every time there was a greater than 70% stenosis. Milder lesions have a higher rate of discrepancies, due to pathology overestimation because of collapse of the vessel and tissue shrinkage, and to the angiographic underestimation that appears when comparing the stenotic segment with a remaining presumably normal artery.

Adult↗

PubMedDate not supplied

Complete response to chemotherapy in intra-abdominal desmoplastic small round cell carcinoma. A case report.

AIMS AND BACKGROUND: The authors report the case of a 23-year-old woman affected by intra-abdominal desmoplastic small round cell tumor (DSRCT) who obtained a complete response to multiagent chemotherapy. DSRCT is a rare, highly aggressive neoplasm generally arising in young people and seldom in females (about 20 cases described in the literature). METHODS: The patient underwent surgical resection of a large 15 x 15 cm mass located in the right lower abdominal quadrant, but after only 2 months later, two liver metastasis were noted. Thus, she was subjected to an aggressive antineoplastic treatment consisting of three groups of alternating non-cross resistant multiagent regimens administered every 21 days (cis-platin-etoposide-adriamycin-bleomicin; gemcitabine-ifosfamide-dacarbazine; methotrexate-5-fluorouracil-folinic acid) for a total of 9 administrations. RESULTS: After one cycle of treatment including the administration of all the three alternated schemes of chemotherapy, a complete disappearance of liver disease was noted. The treatment was relatively well-tolerated and the toxicity was acceptable. At present, after 15 months from diagnosis and 12 months after starting chemotherapy, the patient is disease-free and in good health. CONCLUSIONS: Even though this study regards only a single patient, it is noteworthy because of the rarity of this neoplasm and because of the infrequent complete responses reported in the literature. The efficacy and manageability of the treatment, suggests that both the timing and schedule used could constitute an important therapeutical option for this aggressive and poorly chemo-responsive tumor.

Abdominal Neoplasms↗

PubMedDate not supplied

Programmed cell death in colorectal carcinogenesis.

The most studied mechanism of malignant transformation has been cell proliferation. The relationship between programmed cell death (apoptosis), cell proliferation, and apoptosis regulatory genes (p53 and bcl-2), was studied in normal colonic epithelium, 26 sporadic adenomas both early and late, 25 FAP adenomas, and 34 carcinomas. We showed a decrease in programmed cell death and an increase in cell proliferation during the transition from adenoma to carcinoma. The increase of expression of p53 from early (10%) to late adenomas (87%) contrasted with the decrease of bcl-2 staining. Sixty-two per cent and 23% of carcinomas were reactive for p53 and bcl-2 respectively. Abnormal early activation of the bcl-2 gene, rather than late p53 gene mutation appears to be responsible for inhibition of apoptosis in colorectal carcinogenesis. bcl-2 was higher in FAP adenomas than in sporadic cases, and in carcinomas favouring the accumulation of long-living cells, which are more subject to mutation and thus cancerization.

Apoptosis↗

PubMedDate not supplied

[Histologic findings in laser radiation of myocardial pericrater in dogs].

Laser beam constitutes a potential therapy in modern cardiology. Although its myocardial effects are known, they have been insufficiently evaluated at the surviving myocytes zone surrounding the evaporated crater. In order to assess myocyte cellular and organelar damage, we studied 8 isolated canine hearts radiated with different intensities by a CO2He laser beam 2.4, 3.5, 5, 15, 25, 30 and 40 Watts, varying the exposition time from 1 to 6 sec. Color photographs from the post-radiated lesions on front and depth were obtained. Their volumes were measured applying the cylinder and the cut out-conus formulas according to the shape of the lesions and then the involved tissues were embedded in paraffin for histological studies. Previously, samples of the lesions were fixed in glutaraldehyde for ultrastructural studies. Volumes of the craters were from 0.0004 to 19.57 mm3. Three layers were observed: a) a carbonized internal lining which measured x 15 microns in thickness; b) a coagulation necrotic zone ("gruyere cheese-like"), 70 microns thickness; c) finally more peripherally, a layer consisting of myocytes with patchy homogeneous cytoplasm, and scare positivity for the Barbeito López Trichome Stain (a positive technique in cases of myocardial damage). Ultrastructurally, crater peripherical cells showed cytosol and mitochondrial edema without membrane disruptions. These findings suggest that myocytes surrounding the laser beam crater, show reversible lesions. Therefore laser beam apperrs a safe procedure to be used in myocardium.

Animals↗

PubMedDate not supplied

P-170 glycoprotein expression in gastric and colorectal carcinomas and normal mucosa. An immunocytochemical study.

During the past few years it has become apparent that simultaneous resistance of tumour cells to a number of heterocyclic drugs (multidrug resistance) is often correlated with overexpression of a P-glycoprotein (P-gp or P-170). P-gp expression can be studied by molecular biology and immunohistochemical techniques. The latter provide a rapid, sensitive and specific screening method suitable for testing even a relatively small number of tumour cells like those obtained at biopsy. The aim of this study was to detect and localize the immunohistochemical expression of P-gp in normal and neoplastic gastrointestinal tissue using the Mab JSB-1 in formalin-fixed paraffin-embedded specimens. A particularly striking finding of our study was the consistent, prevalent higher expression of P-gp in the stomach than in the colon, with a higher percentage of immunostaining in normal than in neoplastic tissue. This is in agreement with the fact that not only is the prognosis known to be worse for stomach cancer, but also the response to treatment is lower. Further studies should be carried out to verify the possibility of making routine tests of this kind for the evaluation of multidrug resistance, to guide the selection of patients for treatment of cancer with chemotherapeutic drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

The immunohistochemical expression of cathepsin D in colorectal cancer.

It has been suggested that cathepsin D expression in stromal cells affects the prognosis of breast cancer. With reference to colon and breast cancer, this study verified cathepsin D immunostaining in epithelial and stromal cells of primary tumours and lymph-node metastases from 46 colorectal carcinomas. Eight of 46 cases (17%) were cathepsin D+ both in cancer and stromal cells. No staining was found either in cancer or stromal cells of the remaining cases. The results presented here suggest the possible paracrine influence of another diffusible factor produced by cancer cells which stimulates cathepsin D production in stromal and cancer cells.

Aged↗

PubMedDate not supplied

Multiple synchronous colorectal carcinomas: a ploidy study by image analysis.

Cytometry could represent an ancillary technique to morphology in order to understand whether multiple synchronous colorectal carcinomas arose independently. Twenty-eight multiple synchronous tumours, assessed by means of a computerized image analysis system for DNA ploidy, were categorized as diploid (4) or not diploid (24). The ploidy classes were: DNA-diploid, DNA-tetraploid, and DNA-aneuploid. The DNA Index (DI) ranged from 0,90 to 2,66. The overall concordance rate for ploidy and DI class with synchronous tumours was 69% and 31%, respectively. The high concordance rate in ploidic categories suggests the metastatic origin of our multiple synchronous tumours. Moreover, they showed site, Dukes' classification, degree of differentiation, percentage of ploidy class, and DI distribution comparable to the single colorectal carcinomas. In conclusion, image analysis is a reliable technique to determine the independent clonality or the common origin of multiple colorectal tumours when the evaluation based on the simple histopathological criteria is not satisfactory.

Aged↗