A detailed study of the effects of in vitro interferon treatment on the growth of two variants of the B16 mouse melanoma in the lungs: evidence for non-specific effects

Interferon treatment increases the ability of tumour cells to colonize the lungs. Although it has been suggested that this effect can be explained by increases in the expression of MHC molecules the precise mechanism is still uncertain. The growth in the lungs of a low (F1) and a high colonizing variant (BL6) of the B16 mouse melanoma have been studied after in vitro treatment with interferon. Interferon-gamma, but not interferon-alpha/beta, increased the number of lung colonies formed after intraveneous injection, but not after subcutaneous administration. Treatment also increased the sizes of the lung colonies formed and the number of radiolabelled cells retained by the lungs. However, no clear relationship was observed between the number of colonies formed and the concentration of interferon used. The effect of interferon on F1 was greater than on BL6, but the overall number of colonies formed was very similar. These results suggest that interferon increases the adhesiveness of these cell lines in a fairly non-specific manner, that seems unlikely to involve MHC molecules. As a result of this and other studies the importance of interferon in the process of tumour spread seems very questionable.     

The accuracy of computed tomography in the diagnosis of retroperitoneal blood in the presence of abdominal aortic aneurysm

The use of computed tomography (CT) in the management of patients who are hemodynamically stable with symptoms suggestive of ruptured abdominal aortic aneurysm and in hemodynamically unstable patients without palpable or known aortic aneurysms was analyzed in a retrospective study. One hundred forty-two CT scans were performed; 48 patients had abdominal aortic aneurysms and 35 had no evidence of rupture or retroperitoneal blood. Ten patients had CT scans that showed evidence of rupture, and three patients had CT scans that were thought to be indeterminate for rupture, probably inflammatory. Forty patients underwent laparotomy. Excluding the three patients with inflammatory aneurysms, the results of CT scanning were compared with the findings at laparotomy. The sensitivity of CT scanning for the diagnosis of retroperitoneal blood in the presence of abdominal aortic aneurysm was 77% and the specificity was 100%, with an overall accuracy of 92%. An algorithm for the management of the patient with symptoms suggestive of a ruptured aneurysm is presented.     

Etiology and pathogenesis of hypertension following renal transplantation

Hypertension is a common feature of end-stage renal disease (ESRD) and constitutes a major risk factor for accelerated cardiovascular disease and premature death. While a reduction in the incidence and severity of hypertension is one potential benefit of kidney transplantation, hypertension often remains as a problem after transplantation, even in recipients of wellfunctioning allografts. Despite many studies of the underlying etiologic factors, the mechanisms implicated in post-transplant hypertension are still incompletely understood. A number of variables, including status of the diseased native kidneys, steriod therapy, rejection, recurrence of original disease, activation of the renin-angiotensin system, sodium and calcium metabolism, and transplant renal artery stenosis may play a role in the etiology of hypertension after transplantation. Patients with persistent high blood pressure for more than 3 months after transplantation should be thoroughly investigated, with controlled sodium intake so that proper medical or surgical therapy can be implemented. Since sodium restriction, radionuclide renal scanning, renin levels, or responses to saralasin or captopril may not provide a clear index of various possibilities, an accurate differential diagnosis my also require invasive procedures such as arteriography and/or renal biopsy.     

Participative management: Determining employee readiness

An action research methodology is used to implement participative management on a unit of a municipal community mental health center. A one-group pretest-posttest quasi-experimental design is used to assist unit managers and employees in determining their level of desire for participation in decision-making. Findings suggest an average desire for less rather than more participation.