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Biomedical subjects

M Valente

Publications and source records attributed to M Valente.

306 records · Page 17Linked to original sources
PubMedDate not supplied

Liver and apoptosis.

Apoptosis is an energy-requiring mechanism of cell death which is a physiological event in organ morphogenesis, clone selection of lymphoid cells and cell turnover, but also occurs in many pathological conditions. It is under genetic control, bcl-2 being the major apoptosis suppressing gene, while p53 and c-myc are apoptosis promoting genes. Other factors, such as the Fas/Fas1 system, the caspases cascade, cytokines and enzymes also play a role in determining apoptosis. The term apoptosis was introduced by Kerr to describe this type of death in ischaemic rat liver, and the same Councilman bodies are now considered an example of apoptotic death. Virus-infected hepatocytes bear Fas receptors and apoptosis is induced by binding to the Fas ligand which is expressed by activated T cells; this action is probably mediated by enzymes of the caspase family and/or by granzyme B. The Fas/Fas1 system is also involved in apoptosis occurring in chronic non suppurative destructive cholangitis, in transplant rejection and in other liver diseases, including neoplasms; in the latter Bcl-2 protein and mutations of p53 also seem to play an important role. Cytokines are also frequently involved. Toxins like alcohol probably induce apoptosis by producing active oxidants. Whether aging enhances apopstosis in liver is still controversial. Although many molecular mechanisms have been suggested to be involved the switch on/off of apoptosis is still poorly understood and will be a matter of further investigations.

Aging↗
PubMedDate not supplied

Venous thromboembolism and renal cell carcinoma.

There is a vast amount of literature documenting the relationship between cancer and venous thromboembolism. Nevertheless, many aspects of this association remain obscure and the best approach to be taken towards a patient with apparently idiopathic venous thromboembolism has yet to be defined. We present a case of a patient with venous thromboembolism in whom abdominal ultrasonography, prescribed as a cautionary measure to rule out the presence of a tumour, revealed liver metastases, while the subsequent CAT scan showed hepatic angiomatosis and two small bilateral renal carcinomas. Although there are as yet no indications in the literature on screening patients with idiopathic venous thromboembolism for occult tumours, our case shows how the clinical decision to perform abdominal ultrasonography saved the patient's life.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Thrombosis and cancer.

Although the association between malignant disease and thrombosis was first recognised by Trousseau in 1865, many aspects of this complex relationship are still obscure. Cancer patients have an increased risk of developing thrombosis. Similarly, patients presenting with idiopathic venous thromboembolism are considered to have a higher risk of developing cancer. However, no data exist that warrant thorough screening for cancer in these patients--apart from history taking, physical examination, routine investigations, and chest X-ray. Tumour cells activate the blood coagulation system either by directly stimulating thrombin formation or by inducing mononuclear cells to synthesise procoagulants. Both cancer cells and chemotherapeutic agents damage the endothelium by further enhancing the hypercoagulable state of malignancy. With few exceptions, the diagnosis and treatment of thrombosis in cancer patients are the same as in patients without cancer. Cancer patients are considered eligible for primary prevention of venous thromboembolism when they are receiving chemotherapy, if they have indwelling central venous catheters, when they are immobilised and, more importantly, when they undergo surgery. Secondary prevention in recurrent venous thrombosis may require the administration of oral anticoagulants or, in cases of resistance to warfarin, adjusted doses of heparin.

Humans↗
PubMedDate not supplied

[Validity of the V/Q index in the monitoring of critical patients].

The Authors have controlled the validity of VQI to quantify pulmonary shunt (Qs/Qt). The survey involved (group A) patients who had undergone major surgery and (group B) patients hospitalized in ICU for cardiorespiratory failure. Four subgroups were identified in both the groups according to different values of SaO2. A good correlation, already described by Räsänen, was comproved in the groups and subgroups. However a progressive reduction of the coefficient of correlation from the lower to the higher values of SaO2 was noted. Finally the differences observed between group A and group B, are supposed to be dependent on a greater variability of haemoglobin, in the surgical group, in relation to the time of evaluation.

Analysis of Variance↗
PubMedDate not supplied

[Giant mucocele of appendix. Case report].

Appendiceal mucocele is an uncommon disorder caused by accumulation of mucus within the appendiceal lumen. Mucoceles represent a heterogeneous group comprising various histopathologic lesions including mucosal hyperplasia, cystoadenomas, and cystoadenocarcinomas and prognosis is related to these subtypes. The most common symptom is pain or a palpable mass in the right lower quadrant on physical examination. The preoperative diagnosis is performed with abdominal U.S. and confirmed with CT scan; typical CT scan image is a capsulated cystic mass with calcification of the wall while U.S. pattern shows cystic lesion with the onion skin sign considered a specific sonographic marker for appendiceal mucocele. In conclusion a cystic mass sonographically detected with onion skin sign, in the presence of normal female reproductive organs, suggest the diagnosis of appendiceal mucocele.

Adult↗
PubMedDate not supplied

[Unusual manifestations of Ebstein's disease in a 53 year old adult. Ebstein's disease in an adult].

B.P., asymptomatic until her fifties, was admitted to hospital because of precordial pain. Her ECG and chest X rays were normal. When 52 she was again admitted, because of congestive heart failure. ECG showed repolarization abnormalities and chest X rays showed marked cardiomegaly. 2d echocardiogram was consistent with right atrial dilatation, dislodged posterior leaflet of the tricuspid valve and marked tricuspid regurgitation; these features were consistent with Ebstein anomaly. The patient was successfully treated by digitalis and diuretics. This case shows that in very rare cases this congenital heart disease can produce its clinical manifestations only late in lifetime.

Ebstein Anomaly↗
PubMedDate not supplied

[Bilateral adrenal neuroblastoma of multicentric origin].

Bilateral neuroblastoma is extremely rare. In the literature few cases are reported which are mostly considered to represent metastases rather than multicentric tumoral occurrence. A case of bilateral adrenal neuroblastoma is reported; given its various aspects, and especially the prognosis features, this tumor is, in our opinion, of a multicentric origin.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

[Carcinoid cardiopathy. A study of 40 cases].

Carcinoid is a slowly growing type of tumor; its pathological effects are primarily due to its endocrine symptomatology. Among the main causes of death are heart failure, liver disease and complications due to the tumor size. The purpose of this study was to investigate carcinoid heart disease in a wide necropsy sample. We analyzed 26,921 necropsies performed at the Institute of Pathology of the University of Trieste from January 1, 1976 to December 31, 1985. Out of the 26,921 necropsies we found 59 cases with carcinoid tumor. It is interesting to underline the presence of a second primary tumor in 28.8% of cases and of multiple tumors in 2 cases. In the heart we observed valvular abnormalities with no peculiar features in 16.1% of cases, ischemic heart disease in 52.2% and endocardial thickening in 15.9%. Our series, although rather large, did not show the high frequency of carcinoid heart disease that has been reported by other authors; instead, we observed a rather high prevalence of lesions typical of ischemic heart disease. The endocardial thickening seems to be the most interesting and specific finding.

Adult↗