Small bowel intussusception due to malignant melanoma: primary lesion or metastases? A case report.

Intussusception is a rare condition in the adult population: it is responsible for 1% of all bowel obstructions. In most of intussusceptions a malignant tumor is involved; a lot of studies show that approximately 50% of malignant metastases causing small bowel intussusception are metastatic melanomas. In present paper a case of a small bowel intussusception probably due to metastases of an occult melanoma, in a 69-year-old patient, is presented. Surgery resection, careful research of possible primitive neoplasms and an accurate follow-up program has been the treatment of choice. All the investigations carried out did not allow to identify a possible primitive neoplasm. The last whole body PET carried out 44 months after surgery resulted disease-free.

Meckel diverticulum: one pathology, different clinical presentations. A report of two cases.

Meckel diverticulum is the most prevalent congenital malformation of gastrointestinal tract and usually it remains asymptomaRomatic. Approximately in 25% of cases Meckel diverticulum comes to be symptomatic with various clinical presentations where lower gastrointestinal hemorrhage or intestinal obstruction represent the most frequent clinical outcome. In present paper two cases of complicated Meckel diverticulum in young patients are described; in both cases diagnosis was difficult and initially mistaken with other pathologies. Surgical resection was the treatment of choice.

Different expression of procoagulant activity in human cancer cells cultured "in vitro" or in cells isolated from human tumor tissues.

We studied in a homologous system the procoagulant activity of human tumor cells cultured "in vitro" (1402 primary melanoma, Me 7110/2 metastatic melanoma, Hep G2 hepatoma and GLC1 small cell lung carcinoma) or of cells freshly isolated from different human tumor tissues. Tumor cells cultured "in vitro" possessed and released a factor VII dependent procoagulant activity, which was inhibited by concanavalin A and unaffected by iodoacetamide or HgCl2. The activity released by the cells of metastatic melanoma was higher than that released by the cells of the primary tumor. On the contrary, cancer cells isolated from tumor tissues possessed and released a factor VII independent activity which was inhibited by iodoacetamide of HgCl2 and was not modified by concanavalin A. Therefore, different methods for the preparation of tumor cell suspensions have to be used for the study of tumor procoagulants, since their expression depends very largely on the source of tumor cells. Furthermore, cultured human tumor cells are not an appropriate model for the "in vivo" procoagulant effect of tumor cells.

Enhanced antithrombotic mechanisms in patients with maturity-onset diabetes mellitus without thromboembolic complications.

Some haemostatic parameters have been evaluated in a group of rigorously selected patients with maturity-onset diabetes mellitus without thromboembolic complications and in apparently normal subjects of the same age before and after the venous occlusion test (VOT). In basal conditions diabetics had higher levels of AT III as biological activity and higher fibrinolytic and antifibrinolytic activities than controls. After VOT, F VIII R:Ag increased significantly in both groups, more markedly in controls than in diabetics, while F VIII: C showed no modification. Also AT III R:Ag increased after the test, but such variation was significant only in diabetics; on the contrary, the biological activity of AT III was always significantly decreased after the test. After VOT there were also in both groups highly significant increases in the fibrinolytic and antifibrinolytic activities. Finally, HbA1c levels directly correlated with AT III as biological activity before VOT, but with no other parameter either before or after the test. These data suggest the existence in patients with diabetes mellitus without thromboembolic complications of an activated protective mechanism against intravascular clotting.

Activation of platelet prostaglandin biosynthesis pathway during neoplastic cell-induced platelet aggregation.

In a previous study we found a correlation between metastatic potential and platelet aggregating activity in sublines of a benzopyrene-induced murine fibrosarcoma ( mFS6 ); the purpose of the present work was to elucidate the role of thromboxane biosynthesis by platelets and/or by neoplastic cells in the activation of platelets in this system. The cells of the more malignant subline induced higher aggregation and TxB2 production than those of the non metastasizing one. The supernatants of aggregating cell suspensions contained very few TxB2; furthermore, preincubation of platelets with ASA or Apyrase resulted in inhibition of aggregation and TxB2 production, while preincubation of the cells was ineffective; these results suggest the platelet origin of the measured TxB2 and indicate that platelet-derived ADP plays an important role in their activation, while the production of ADP by the cells does not seem to be relevant in this model. The involvement of platelet prostaglandin biosynthesis pathway in neoplastic cell induced platelet activation could play an important role in the development of platelet-dependent tumour metastasis.

Effects of nicardipine on the ex vivo release of eicosanoids after experimental subarachnoid hemorrhage.

The activation of lipid peroxidation and the enhancement of arachidonic acid metabolism have been demonstrated as indicators of brain damage after subarachnoid hemorrhage (SAH). Meanwhile, the final common pathway of neuronal damage seems to be related to the impaired homeostasis of Ca++. The present study evaluated the effect of the calcium-antagonist nicardipine on arachidonate metabolism after experimental induction of SAH. The ex vivo release of four eicosanoids (prostaglandin (PG)D2, PGE2, 6-keto-PGF1 alpha, and leukotriene (LT)C4) was measured at different intervals after SAH induction. Rats were separated into the following three groups: a sham-operated group, an SAH group (rats were injected with 0.3 ml autologous arterial blood), and an SAH-treated group (after SAH induction, rats were treated with nicardipine 1.2 mg/kg intraperitoneally). Nicardipine significantly decreased the ex vivo release of PGD2 at 48 hours after SAH (p less than 0.01). The release of PGE2 was significantly enhanced at 6 hours after SAH, while in the nicardipine-treated group PGE2 release is significantly reduced. Nicardipine also affects the lipoxygenase pathway, reducing the release of LTC4 at 1, 6, and 48 hours after SAH induction. The results of the present study show that nicardipine treatment exerts an inhibitory effect on both biochemical pathways of arachidonic acid metabolism; aside from vascular effects, nicardipine could exert a protective role against the release of arachidonate metabolites, which could play a significant role in the pathogenesis of brain damage after SAH.

CSF leukotriene C4 following subarachnoid hemorrhage.

Leukotrienes derive from arachidonic acid metabolism via the lipoxygenase pathway and modulate several cellular events. In the central nervous system, leukotrienes are mainly synthesized in the gray matter and in vascular tissues. Their production is enhanced in ischemic conditions and in experimental subarachnoid hemorrhage (SAH). Previous studies have indicated the ability of the leukotrienes C4 and D4 to constrict arterial vessels in vivo and in vitro and have suggested their involvement in the pathogenesis of cerebral arterial spasm. In the present study, the authors measured lumbar and cisternal cerebrospinal fluid (CSF) levels of leukotriene C4 in 48 patients who had suffered aneurysmal SAH. In 12 of the cases, symptomatic and radiological spasm was evident. The mean lumbar CSF level of immunoreactive-like activity of leukotriene C4 (i-LTC4) was significantly higher (p less than 0.005) than in control cases, while the cisternal CSF level was higher than the lumbar mean concentration (p less than 0.005). Patients presenting with vasospasm had significantly higher levels of i-LTC4 compared to patients without symptomatic vasospasm. This is the first report concerning monitoring of i-LTC4 levels in the CSF after SAH. The results of this study suggest that: 1) metabolism of arachidonic acid via the lipoxygenase pathway is enhanced after SAH; 2) the higher cisternal CSF levels of i-LTC4 may be part of the biological response in the perianeurysmal subarachnoid cisterns after the hemorrhage; and 3) the higher CSF levels of i-LTC4 in patients presenting with vasospasm suggest that a relationship exists between this compound and arterial spasm and/or reflect the development of cerebral ischemic damage.

[Invagination of a gastric leiomyoma causing duodenal subocclusion and cholestasis]. / Invaginazione di leiomioma gastrico causante subocclusione duodenale e stasi biliare.

The case is reported of a 78 year old female admitted to our Department with symptoms compatible with intestinal obstruction and melena. Upper gastrointestinal x-ray examination and endoscopy did not lead to a precise diagnosis. On the contrary, double contrast x-ray examination revealed the presence of a probably benign gastric tumour with gastroduodenal intussusception. Cholestasis was also present, as suggested by elevated serum conjugated bilirubin levels and by intravenous cholangiography. These findings were confirmed during surgical operation; a partial gastrectomy with gastroentero anastomosis was performed; histologic examination showed that the tumour was a gastric leiomyoma. All the symptoms disappeared quickly and the patient is still in good health after 2 years.

In vitro effect of reduced glutathione on platelet function.

BACKGROUND: Generation of reactive oxygen species has been suggested to represent an important regulatory mechanism of platelet reactivity in both physiological and pathological conditions, and free-radical scavengers may inhibit platelet activation. The purpose of the present study was to investigate the effect of reduced glutathione (GSH) on different platelet functions stimulated by ADP, collagen or PAF. METHODS: Platelet aggregation was investigated by Born's method. TxB2 and PDGF levels were measured by radioimmunoassay. RESULTS: GSH at the lowest dose (1 mM) did not significantly modify aggregation, TxB2 production or PDGF release induced by ADP or PAF, while at higher concentrations (3 mM or 10 mM) it significantly inhibited all parameters. Collagen-induced platelet activation was remarkably less sensitive to GSH, since aggregation was not significantly reduced, while TxB2 production was reduced by GSH when employed at concentrations of 3 mM or 10 mM, and PDGF release was inhibited only by the highest dose (10 mM). IC50 for inhibition of platelet aggregation, TxB2 production and PDGF release were between 1.43 and 2.36 mM when platelets were stimulated with ADP, between 2.23 and 8.90 mM when PAF was used and between 8.00 and 16.30 mM when collagen was the agonist. CONCLUSIONS: Our data suggest that GSH may act as a physiological inhibitor of platelet activation and may therefore contribute to the regulation of platelet reactivity.

In vitro Effect of Verapamil on Platelet Activation Induced by ADP, Collagen or Thrombin.

We studied the effects in Vitro of the calcium channel blocker verapamil (0.1, 0.2 or 0.3 mM) on platelet aggregation, on cytoplasmic Ca(+ +) levels and on TxB(2) production after activation of platelets with adenosine diphosphate (ADP) (100 µM), collagen (20 µg/ml) or thrombin (1 U/ml). A Platelet Ionized Calcium Aggregometer was used and washed, aequorin loaded platelets were employed. The drug was able to inhibit similarly and always significantly aggregation, Ca(+ +) fluxes and TxB(2) production when collagen was the agonist. Furthermore, inhibition of aggregation and TxB(2) production was significant at all the concentrations tested when platelets were activated by ADP or thrombin, but in this case inhibition of Ca (+ +) fluxes was observed only with the higher concentrations of the drug (0.2 or 0.3 mM). Hence, with these two last agonists inhibition of Ca(+ +) movements was less pronounced than inhibition of aggregation or TxB(2) production. These data suggest that platelet activation by collagen depends directly and almost exclusively on Ca(+ +) fluxes through biological membranes, while activation by ADP or thrombin is less strictly related to Ca(+ +) movements. Indeed, with these last two agonists verapamil may inhibit platelet activation also by calcium-independent mechanism(s).

Tumor cells induce platelet aggregation and intraplatelet calcium ion movements.

We studied platelet aggregation and changes in cytosolic Ca(++) concentrations induced by cells isolated from 5 human tumor tissues (2 hepatocellular carcinomas, 1 colon carcinoma, 1 gastric carcinoma and 1 pancreatic carcinoma). A Platelet Ionized Calcium Aggregometer was used and washed, aequorin loaded platelets were employed. Tumor cells were able to induce aggregation and an increase in cytoplasmic Ca(++) concentrations in the presence of trace amounts (10 µl) of PPP, while no aggregating response was found after addition of fibrinogen alone to washed platelets. The platelet aggregating activity of tumor cells was maintained in the presence of factor VII deficient plasma or of factor VIII deficient plasma, and disappeared completely when factor X deficient plasma was added to washed platelets. Furthermore, tumor cell induced platelet aggregation and Ca (++) movements were inhibited by hirudin (100 U/ml), a specific thrombin inhibitor, while concanavalin A (100 µg/ml), a tissue factor inhibitor, had no effect. Finally, preincubation of neoplastic cells with HgCl(2) (0.5 mM), a cysteine protease inhibitor, markedly decreased their ability to induce aggregation and Ca(++) movements; on the contrary, incubation of cells with soybean trypsin inhibitor (10 µg/ml), a serine protease inhibitor, or with concanavalin A (100 µg/ml) had no effect. These data suggest that cells isolated from human tumor tissues activate platelet function through the generation of thrombin, due to a cysteine protease which directly activates factor X.

Platelet activation by cells isolated from human tumor tissues: effect of cyclooxygenase blockade.

We have studied in a homologous system the effect on different platelet functions of cells isolated from 26 human tumor tissues (11 breast carcinomas, 11 colon carcinomas, 2 pancreatic carcinomas, 1 gastric carcinoma and 1 esophageal carcinoma). Tumor cells (10(5)/ml) significantly increased platelet adhesion to glass beads; they were also found to possess a potent platelet aggregating activity and aggregation was accompanied by significant release of ATP and platelet derived growth factor (PDGF) and by production of TXB(2). Preincubation of platelets with a low concentration (1 µM) of indobufen, a cyclooxygenase inhibitor, significantly reduced tumor cell induced TXB(2) production and ATP release, while the other platelet functions were not modified. Higher concentrations of the drug (10 or 100 µM) were also able to inhibit tumor cell-induced platelet aggregation and PDGF release, while platelet adhesion to glass beads was unchanged even at these doses. Finally, preincubation of neoplastic cells with indobufen (400µM) had no effect on their ability to induce platelet aggregation, TXB(2) production and ATP release. These data demonstrate that cyclooxygenase blockade in platelets has different effects on several platelet functions activated by the tumor cells that were investigated.

Thromboxane production by platelets during tumor cell-induced platelet activation.

We have evaluated in a homologous system the mechanisms of platelet activation by cells isolated from fresh human tumor tissues and the role of thromboxane B2 (TxB2) generation in this process. Thirty-eight of the 46 tumor tissues considered showed a high platelet-aggregating activity, with no particular distribution in any specific tumor type. Apyrase caused a nonsignificant reduction in the aggregation response, hirudin did not change it, while iodoacetic acid or p-hydroxymercuriphenylsulfonate, specific cysteine proteinase inhibitors, significantly reduced the platelet-aggregating capacity of these tumor cells. In 9 colon carcinomas and in 8 breast carcinomas the levels of TxB2 produced by platelets after addition of tumor cells were measured: tumor cell-induced platelet aggregation was accompanied by a significant production of the metabolite; indobufen, a cyclooxygenase inhibitor, significantly reduced aggregation and particularly TxB2 production, while the drug had no effect on both parameters if preincubated with tumor cells only. These data suggest that cells isolated from different human tumor tissues activate platelets through the activity of tumor-associated cysteine proteinase(s); platelet aggregation by tumor cells is largely dependent on arachidonic acid metabolism in platelets, while such metabolism in tumor cells does not play a significant role.

Proaggregating and procoagulant activities of human mesothelioma tumor cells at different stages of "in vitro" culture.

BACKGROUND: The mechanisms of the interactions between tumor cells and the hemostatic system are not completely understood; the purpose of this study was to elucidate whether tumor cells grown "in vitro" express the same proaggregating and procoagulant activities as cells isolated from tumor tissues, and whether the activities of such cultures are constant and consistent over time. METHODS: Tumor cells were collected and cultured from the pleural fluid of a 71-year-old patient with a sarcomatous malignant mesothelioma. Platelet aggregating activity was studied by adding tumor cells to platelet rich plasma or to washed, aequorin-loaded platelets. The procoagulant activity of the tumor cells was measured by the one-stage recalcification time of different humans plasma substrates. RESULTS: Cells harvested after 4 culture passages possessed low, ADP-dependent platelet aggregating activity, while those studied after 16 or 40 passages activated platelets through the production of thrombin. In the washed platelet system and in the presence of trace amounts of platelet poor plasma, the difference in the aggregating activity of various tumor cell populations was more evident. Normal mesothelial cells did not induce platelet aggregation. Procoagulant activity (tissue factor-like) was low in normal mesothelial cells and in tumor cells after 4 passages, and it was about 10 times higher in tumor cells after 16 or 40 passages. CONCLUSIONS: Results obtained with tumor cells cultured "in vitro" should be considered with caution because their effects are different from those of freshly isolated cells and may not be constant in the different culture passages.

Haemostatic variables, serum lipid abnormalities and vascular complications in diabetes mellitus: a 5 year follow-up study.

The relationship among blood lipids, haemostatic and fibrinolytic parameters have been evaluated, during a follow-up study, in 27 non-insulin dependent (type II) diabetic patients. Upon recruitment, and in periodical controls, we observed that plasma triglycerides and VLDL levels correlated inversely, and HDL directly, with the fibrinolytic activity of plasma and euglobulin precipitate. Furthermore triglycerides and VLDL correlated directly with Factor VIII antigen (vWFAg). After 5 years in the study, 12 patients (44%) had macroangiopathic complications, and 9 of these subjects showed persistently high levels of triglycerides (above 2.36 mmol/l). These haemostatic and lipid components, however, do not influence the progression of diabetic retinopathy and nephropathy. The alterations of lipid, haemostatic and fibrinolytic parameters and their possible relationships seem to play an important role in the occurrence of diabetic macroangiopathy.

Effect of interferon alpha, interferon gamma and tumor necrosis factor on the procoagulant activity of human cancer cells.

BACKGROUND: It is not known whether the different cytokines may influence the procoagulant activity of cancer cells; the purpose of this study was to investigate the effect of interferon alpha, interferon gamma and tumor necrosis factor on the procoagulation capacity of human cancer cells cultured "in vitro" or isolated from tumor tissues. METHODS: "In vitro" cultured tumor cell lines were derived from a patient with malignant mesothelioma and a patient with lung adenocarcinoma. Cells isolated from 6 carcinomas of different origin were also investigated. The procoagulant activity of the cells before and after treatment with the cytokines was expressed as RBT U/10(5) cells or RVV U/10(5) cells. RESULTS: Short-term incubation of tumor cells cultured "in vitro" with cytokines did not modify their procoagulant activity; after longer incubation however, interferon alpha induced a significant increase in the procoagulant activity of mesothelioma cells, while interferon gamma induced and increase in the procoagulant activity of lung adenocarcinoma cells. Furthermore, short-term incubation of cells isolated from tumor tissues with interferon gamma or tumor necrosis factor resulted in a significant increase of procoagulant activity, while interferon alpha had no effect. CONCLUSIONS: Altogether, these data demonstrate that the cytokines may influence the expression of the different procoagulant activities of tumor cells.

Effect of mental stress on platelet function in normal subjects and in patients with coronary artery disease.

We studied the effect of emotional stress (mental arithmetic for 10 min) in 10 postinfarction patients and in 10 age-matched apparently healthy subjects as controls. Blood samples for platelet function studies and for the determination of epinephrine levels in serum were taken in basal conditions, at the end of mental stress and after 30 min of recovery. Patients were studied twice, in washout of medications and after oral administration of dipyridamole, 200 mg twice a day for 6 consecutive days. Mental stress induced in patients significant increments in different hemodynamic parameters (heart rate, systolic blood pressure and diastolic blood pressure) and in serum epinephrine levels. Concomitantly, the test produced a significant increase in platelet aggregation (induced by 3 microM ADP or 1 microgram/ml collagen), the formation of circulating platelet aggregates and an increase in plasma thromboxane B2 levels. Hemodynamic parameters and platelet function tests returned to baseline values after 30 min. Similar activation of hemodynamic parameters, similar increase in epinephrine levels and lower increase in platelet function by emotional stress were observed in control subjects. Treatment of patients with dipyridamole had no effect on stress-induced increase in hemodynamic parameters and epinephrine levels, but decreased stress-related platelet activation. These data can contribute to a better understanding of the complex relationships between psychosocial factors, the hemostatic system and vascular disease.

Antithrombin III biological activity and emotional stress in patients with coronary artery disease.

We studied the effect of emotional stress (mental arithmetic for 10 minutes) in ten postinfarction patients and in ten age-matched, apparently healthy subjects as controls. Blood samples for the determination of epinephrine and AT III levels were taken in basal conditions, at the end of mental stress and after 30 minutes of recovery. Mental stress induced a significant increase in epinephrine levels and a significant decrease in AT III levels in control subjects. Both parameters returned to baseline values after 30 minutes of recovery. On the contrary, in postinfarction patients AT III levels of recovery were still significantly lower than those of baseline, suggesting a reduced ability to restore the original concentration of this physiologic inhibitor. Our data can contribute to a better understanding of the complex relationships among phychosocial factors, the haemostatic system and vascular disease.

Effect of nimodipine on arachidonic acid metabolites after subarachnoid hemorrhage.

Arachidonic acid metabolites are under investigation as possible vasoactive agents involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage. Prostaglandins, as well as other vasoactive compounds, activate contractile proteins through utilization of extracellular bound Ca++ to the intracytoplasmic free fraction. Recently, calcium-antagonists, mainly Nimodipine, have been proposed for the prophylaxis and/or reversal of the ischemic damage caused by vasospasm. Nimodipine failed to reduce vasospasm incidence in a series of 30 patients admitted with diagnosis of subarachnoid hemorrhage from ruptured intracranial aneurysm. Nimodipine failed to reduce level of four arachidonate metabolites measured (prostaglandin D2, prostacyclin, thromboxane B2 and leukotriene C4) in lumbar and cisternal CSF. After subarachnoid hemorrhage there is a significant increase of CSF levels of arachidonate metabolites; in perianeurysmic cisterns level of prostaglandin D2, thromboxane B2 and leukotriene C4 are significantly higher than lumbar CSF levels. Moreover, cisternal CSF level of prostaglandin D2 and leukotriene C4 are significantly higher in patients with symptomatic vasospasm. Nimodipine did not significantly modify CFS level of arachidonate metabolites: this suggests that Nimodipine treatment, which definitely improves long-term results of patients for intracranial aneurysms, could exert its pharmacological action reducing Ca++ intake from the extracellular compartment and preventing a direct toxic effect of calcium, without a direct action against the release of vasoactive compounds.