Perfluorochemicals as US contrast agents for tumor imaging and hepatosplenography: preliminary clinical results

In animals, perfluorochemicals (PFCs) are effective ultrasound (US) contrast agents that produce hepatic, splenic, and tumor enhancement. The use of Fluosol-DA 20%, an emulsion of perfluorodecalin and perfluorotripropylamine, was studied in nine non-critically ill patients with cancer who had liver lesions. US studies without Fluosol were compared with studies obtained 24, 48, and 72 hours after Fluosol infusion. Vital signs and extensive laboratory analyses are performed before and after Fluosol infusion. Liver metastases from colonic, pancreatic, and gastric carcinoma exhibited rim or diffuse enhancement after a Fluosol dose of 1.6 g/kg or greater. Fluosol produced echogenic enhancement of the liver and spleen relative to kidney at a dose of 2.4 g/kg, allowing the detection of nonenhancing lesions. In addition, Fluosol at a dose of 1.6 g/kg or greater allowed detection of lesions not seen before contrast medium was administered in three of the seven patients studied. There was a mild increase in the level of serum glutamic oxaloacetic transaminase in two patients, one given 2.4 and the other 3.2 g/kg of Fluosol. Mild and transient allergic reactions without change in vital signs were experienced by two patients.     

Surgical aspects of chronic peritoneal dialysis in the neonate and infant under 1 year of age.

Since 1982 eight patients under 1 year of age with end-stage renal failure have been treated by chronic peritoneal dialysis (CPD) following insertion of an abdominal Tenckhoff catheter. We routinely perform a partial omentectomy now, and in males undertake bilateral exploration of the groins at the time of catheter insertion, with herniotomy or ligation of the patent processus vaginalis as required. Up to January 1990, 19 straight double-cuff catheters had been inserted with a total follow-up of 244.5 patient months. The median age at the initial catheter insertion was 14.6 weeks (range, 2 days to 11 months) and the median weight was 3.89 kg (range, 2.2 to 5.5). Peritonitis was the most common complication, with 46 episodes, representing one episode of peritonitis per 5.3 patient months on dialysis. The frequency of peritonitis has decreased in the last 6 months since all patients have been dialysed by two caregivers. The present rate of peritonitis is 1 episode per 10 patient months on dialysis. One patient has died of septicemia secondary to associated congenital abnormalities, one patient has regained renal function, and two patients have been transplanted, one successfully. Five patients are currently dialysing via their abdominal Tenckhoff catheters and awaiting transplantation. We conclude that neonates and infants under 1 year of age can be treated satisfactorily by CPD to enable successful preparation for transplantation later in childhood.     

Physicians' information needs: analysis of questions posed during clinical teaching

OBJECTIVE: To describe information requests expressed during clinical teaching. SETTING: Residents' work rounds, attending rounds, morning report, and interns' clinic in a university-based general medicine service. SUBJECTS: Attending physicians, medical house staff, and medical students in a general medicine training program. METHODS: An anthropologist observed communication among study subjects and recorded in field notes expressions of a need for information. We developed a coding scheme for describing information requests and applied the coding scheme to the data recorded. Based on assigned codes, we created a subset of strictly clinical requests. MEASUREMENTS: Five hundred nineteen information requests recorded during 17 hours of observed clinical activity were selected for detailed analysis. These requests related to the care of approximately 90 patients by 24 physicians and medical students. Sixty-five requests were excluded because they were not strictly clinical, leaving a subset of 454 clinical questions for analysis. MAIN RESULTS: On average, five clinical questions were raised for each patient discussed. Three hundred thirty-seven requests (74%) concerned patient care. Of these 337 questions, 175 (52%) requested a fact that could have been found in a medical record. Seventy-seven (23%) of these questions, motivated by the needs of patient care, were potentially answerable by a library, a textbook, a journal, or MEDLINE. Eighty-eight (26%) of the questions asked for patient care required synthesis of patient information and medical knowledge. CONCLUSIONS: Clinicians in the study settings requested information frequently. Many of these information needs required the synthesis of patient information and medical knowledge and thus were potentially difficult to satisfy. A typology is proposed that characterizes information needs as consciously recognized, unrecognized, and currently satisfied.     

Renal allograft rejection: induction and function of adhesion molecules on cultured epithelial cells.

The interaction of graft-infiltrating immune cells with donor parenchymal cells is an important early event in allograft rejection. This binding is stabilized by interaction of antigen-independent 'adhesion' molecules expressed on the two cell types. As the level of expression of these molecules can be altered during inflammation, a series of experiments was performed to examine the effects of the inflammatory cytokines interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) on adhesion molecules expressed by cultured human renal tubular epithelial cells. These cells constitutively expressed ICAM-1 and LFA-3. Incubation with IFN-gamma increased expression of ICAM-1 but had no significant effect on expression of LFA-3 (P greater than 0.05). Incubation with TNF-alpha increased expression of both ICAM-1 and LFA-3; IFN-gamma synergized with TNF-alpha to further augment expression of these molecules. Peripheral blood lymphocytes (PBL) showed an enhanced binding to allogeneic renal epithelial cell monolayers which had been pretreated with IFN-gamma or TNF-alpha. MoAbs specific for ICAM-1 or its ligand LFA-1 inhibited adhesion of PBL to either IFN-gamma- or TNF-alpha-pretreated renal cells. By contrast, antibodies specific for LFA-3 or its ligand CD2 only significantly blocked PBL adhesion to renal cells which had been pretreated with TNF-alpha. Combination of antibodies specific for multiple components of the adhesion systems produced greater inhibition of adhesion than was produced by any single MoAb. These results suggest that the inflammatory cytokines IFN-gamma and TNF-alpha up-regulate expression of functional ICAM-1 and LFA-3 molecules which can augment the binding of potentially graft-damaging lymphoid cells to renal tubular epithelial cells.     

Colonization and maintenance of murine embryonic stem cells on poly(alpha-hydroxy esters)

The aim of this study was to determine the ability of various poly(alpha-hydroxy esters) to support the in vitro propagation of murine embryonic stem (ES) cells in an undifferentiated state. To this end, ES cell colonization, growth and Oct-4 immunoreactivity following a 48 h culture period upon poly((D,L)-lactide), poly((L)-lactide), poly(glycolide) and poly((D,L)-lactide-co-glycolide) (PLGA) were assessed. By the analysis of live and dead cell number indices and Oct-4 immunoreactivity, ES cell colonization rate during a 48 h culture period was found to be significantly greater on PLGA compared to all the other unmodified poly(alpha-hydroxy esters) tested. Surface treatment of all polymers with 0.1m potassium hydroxide revealed a significant increase in ES cell live numbers when compared to all unmodified polymers, thus revealing a correlation between polymer content, hydrophilicity and colonization rate. These data suggest that surface treated poly(alpha-hydroxy esters) may be employed for ES cell scale up procedures and in tissue engineering applications requiring the colonization of scaffolds by ES cells in an undifferentiated state. According to such applications, once the designated scaffold has been colonized, ES cell directed differentiation into the desired and fully differentiated, functional adult tissue may then be effected.