Endogenous nitric oxide acts as a natural antithrombotic agent in vivo by inhibiting platelet aggregation in the pulmonary vasculature.

Nitric oxide (NO) is a powerful vasodilator and an inhibitor of platelet aggregation in vitro. While the ability of NO to modulate vascular tone in vivo has been proven, only a few studies have assessed its platelet inhibitory activity in vivo. We have employed two complementary animal models of pulmonary platelet thromboembolism to assess the antithrombotic activity of endogenous NO in vivo. The inhibition of nitric oxide synthase (NOS) by L-NAME significantly potentiated while the administration of the NOS substrate L-arginine significantly reduced the accumulation of 111In-labelled platelets in the pulmonary vasculature of rabbits induced by intravenous collagen plus epinephrine. L-NAME or L-arginine did not, however, modify 111In-labelled erythrocyte distribution in lungs and phenylephrine had no effect on platelet accumulation following collagen + adrenaline, suggesting that the effects of L-NAME were not due to vasoconstriction but rather to a direct modification of platelet function. In mice, L-NAME significantly reduced the dose of collagen + adrenaline required to induce thromboembolic mortality, increased the fall in circulating platelets and increased the % of pulmonary vessels occluded by platelet thrombi. The effects of L-NAME were reversed by L-arginine but not by a dose of nicardipine exerting maximal vasodilatation. Phenylephrine did not potentiate collagen + adrenaline-induced mortality. In the pulmonary vasculature in vivo, endogenous NO inhibits collagen + adrenaline-induced aggregation and enhances platelet disaggregation. This natural modulator function of NO is exerted via a direct effect on platelets and not as a result of haemodynamic changes.

Chlorambucil carcinogenesis in BALB/c mice.

Chlorambucil, a drug used in the treatment of neoplastic and non-neoplastic disease, was administered by gavage to BALB/c mice at a dose of 1.0 mg/kg body wt. 5 times per week for 12 weeks to test its carcinogenicity. The survival was statistically reduced in treated animals of both sexes (P less than 0.001). The treatment induced a significant increase in lung tumours (males, P less than 0.001; females, P less than 0.001) and lymphoreticular system tumours (males P less than 0.01; females, P less than 0.001) in both sexes and mammary carcinomas in female mice (P less than 0.05). These results with other investigations reported in literature, suggest that chlorambucil is carcinogenic in laboratory animals, mutagenic and that it could be a potential carcinogenic hazard to man.

Amyloid tumours in the soft tissues of the legs. Case report and review of the literature.

We present a case of multiple amyloidomas occurring in the calves of a 61-year-old woman, without systemic amyloidosis or plasma cell dyscrasia. The disappearance of Congo red positivity after potassium permanganate treatment and immunohistochemical results showed that this was a case of reactive AA amyloidosis. True soft tissue amyloidomas are extremely rare, and this is the first case of AA amyloidoma in the soft tissues of the legs.

Distal intramural spread in colorectal cancer: a reappraisal of the extent of distal clearance in fifty cases.

Fifty colorectal carcinomas were investigated to demonstrate distal intramural spread (DIS). In 17 cases (34%) a DIS ranging from 0.25 to 3.5 cm was present. DIS was positively correlated with stage C2 (p less than 0.01), lymph node metastasis (p less than 0.03) and infiltrative growth of the tumor (p less than 0.05). Our results show that DIS is a relatively frequent event but of limited extension. In fact, a distal clearance margin of 2 cm was considered safe for all patients but one C2 mucoid case. No pathologic feature can predict preoperatively the presence and extent of DIS.

5-Fluorouracil carcinogenesis in BALB/c mice.

5-Fluorouracil, a drug mainly used in the treatment of gastrointestinal tract neoplasms, was administered i.p. to BALB/c mice at the dose of 30 mg/kg body weight once a week for 50 weeks to test its carcinogenicity. The treatment induced a significant increase in lung tumor in both sexes (males, p less than 0.05; females, p less than 0.01) and tumors of the lymphoreticular system in female mice (p less than 0.001). These results suggest that 5-fluorouracil is carcinogenic in mice.

Bilateral primary malignant lymphoma of the breast. A case report.

A case of bilateral primary malignant lymphoma of the breast in a 30 year old woman is described. The tumors were first discovered during a self-examination of the breast at the 7th month of pregnancy. Thereafter they rapidly increased in size. The patient underwent simple bilateral mastectomy, and histological examination revealed a centroblastic/centrocytic lymphoma. The patient is alive and well 9 months after mastectomy.

[Synovial sarcoma. Immunohistochemical study of 4 cases]. / Sarcoma sinoviale. Studio immunoistochimico di 4 casi.

We examined 4 cases of synovial sarcoma, 3 biphasic-one of which was located in the abdominal wall-and 1 monophasic, in patients between 16 and 54 years. Immunohistochemistry revealed the capacity of these neoplasms to express mesenchymal and epithelial markers, not only in the sarcomatous-like stroma but also in gland-like component. We also found that in the epitheliomorphous cells vimentin positivity had a characteristic basal position whereas EMA and cytocheratins were much more positive in the apical zone. This double positivity could be profitably utilized when the predominance of the gland-like component in a synovial sarcoma requires differential diagnosis from metastatic adenocarcinoma.

Fatal Strongyloides stercoralis hyperinfection diagnosed by Papanicolaou-stained sputum smears.

Opportunistic infections with Strongyloides stercoralis are rare in Western countries. However, individuals with cellular immunity defects may develop a disseminated infection. We report the case of a 78-year-old Italian male who developed progressive respiratory failure six weeks after initiation of corticosteroid therapy for temporal arteritis. Infective filariform Strongyloides stercoralis larvae, found in the sputum one day before death, clarified the complex clinical picture. It is advisable that before and during immunosuppressive treatments, the stools and body fluids of patients should be screened for parasites.