Nonoperative management of liver and/or splenic injuries: effect on resident surgical experience

Changes in the management of trauma over the past few years are significantly affecting postgraduate surgical education, with the lack of operative trauma experience being a major concern in some programs. This problem is accentuated in residency programs that obtain their trauma caseload primarily from blunt injury. Our experience over the past 6 years confirms that the growing trend toward nonoperative management of blunt liver and spleen injuries in adults is likely to exacerbate this problem. Blunt trauma admissions to our Level I trauma center increased from 2888 from 1991 through 1993 (group A) to 3587 from 1994 through 1996 (group B). Liver and/or splenic injuries occurred with equal frequency in both groups. Whereas diagnostic peritoneal lavage was used in 26 per cent of group A, its use dropped to 2 per cent in group B as abdominal computerized tomography was used more frequently to evaluate these patients. Nonoperative management increased from 10 per cent of group A to 54 per cent of group B. As a result, therapeutic laparotomies dropped from 85 in group A (58% of patients with liver/splenic injuries) to 74 (35%) in group B and nontherapeutic laparotomies from 48 (33%) to 23 (11%). While the evolution in the management of blunt liver and splenic injuries has resulted in the avoidance of nontherapeutic laparotomies, the operative caseload available to surgical housestaff has been adversely affected. Although the Residency Review Committee has stressed the importance of the critical care management of these patients, the criteria used to evaluate the number of trauma cases in postgraduate surgical education may need to be revised.     

Subdiaphragmatic and intrathoracic paraspinal malignant peripheral nerve sheath tumors: a clinicopathologic study of 25 patients and 26 tumors

BACKGROUND: To determine the effects of anatomic site on the presentation and diagnosis of malignant peripheral nerve sheath tumors (MPNSTs) and on the treatment and outcomes of the patients, the authors initiated a study of these tumors at different sites. An earlier report described MPNSTs of the buttock and lower extremity, and the current series analyzes those presenting at intrathoracic (IT) and subdiaphragmatic (SD) paraspinal sites. METHODS: The authors reviewed data on patients with paraspinal MPNSTs who were seen at Memorial Hospital during the period 1960-1995 and for whom histologic slides were available. Various clinicopathologic parameters and their effects on patient outcomes were examined. RESULTS: Twenty-five patients with 26 tumors were evaluated. Seven tumors were IT and 19 were SD; 60% of the patients had neurofibromatosis type 1 (NF1). Most patients presented with pain, and a diagnostic delay (of 3 months to 2 years) was often noted. Mean tumor sizes for SD and IT tumors were 14.3 cm and 6.6 cm, respectively. Most MPNSTs were composed of spindle cells in fascicles. Twenty-seven percent exhibited divergent differentiation. Twenty-four tumors were high grade, and a low grade component was identified in 8 tumors. Surgical resection was attempted for 23 tumors (88%), but complete resection was achieved in only 6 cases (23%). Eighty percent of the patients died of their tumors, 2-year and 5-year survival rates were 35% and 16%, and median survival was 8.5 months. Significant prognostic factors were tumor size <5 cm, the presence of a low grade component, and complete tumor resection. CONCLUSIONS: Paraspinal MPNSTs have more aggressive behavior than peripherally located tumors, mainly because of the difficulty encountered in resecting them completely. Prognoses of patients with MPNST at this site appear to be affected by resection status, tumor size, and tumor grade.     

Reaction and total cross sections for low energy pi + and pi - on isospin zero nuclei

We calculated the electrostatic force between a planar interface, such as a planar-supported lipid bilayer membrane, and the tip of a stylus on which another lipid bilayer or some other biomacromolecular system might be deposited. We considered styli with rounded tips as well as conical tips. To take into account the effect of dynamical hydrogen-bonded structures in the aqueous phase, we used a theory of nonlocal electrostatics. We used the Derjaguin approximation and identified the systems for which its use is valid. We pointed out where our approach differs from previous calculations and to what extent the latter are inadequate. We found that 1) the nonlocal interactions have significant effects over distances of 10-15 A from the polar zone and that, at the surface of this zone, the effect on the calculated force can be some orders of magnitude; 2) the lipid dipoles and charges are located a distance L from the hydrophobic layer in the aqueous medium and this can have consequences that may not be appreciated if it is ignored; 3) dipoles, located in the aqueous region, can give rise to forces even though the polar layer is unchanged, and if this is ignored the interpretation of force data can be erroneous if an attempt is made to rationalize an observed force with a knowledge of an uncharged surface; 4) the shape of the stylus tip can be very important, and a failure to take this into account can result in incorrect conclusions, a point made by other workers; and 5) when L is nonzero, the presence of charges and dipoles can yield a force that can be nonmonotonic as a function of ionic concentration.     

The low-affinity dihydropyridine receptor and Na+/Ca2+ exchanger are associated in adrenal medullary mitochondria

The effect of Ca2+ channel-acting drugs on bovine adrenal mitochondria Ca2+ movements was investigated. Mitochondrial Ca2+ uptake is performed by an energy-driven Ca2+ uniporter with a Km of 20.9 +/- 3.2 microM and Vmax of 148.1 +/- 7.2 nmol 45Ca2+ min-1 mg-1. Ca2+ release is performed through an Na+/Ca2+ antiporter with a Km for Na+ of 4.2 +/- 0.5 mM, a Vmax of 7.5 +/- 0.4 nmol 45Ca2+ min-1 mg-1, and a Hill coefficient of 1.4 +/- 0.2 Ca2+ efflux through the mitochondrial Na+/Ca2+ exchanger was inhibited by several dihydropyridines (nitrendipine, felodipine, nimodipine, (+)isradipine) and by the benzothiazepine diltiazem with similar potencies. In contrast, neither CGP 28392, Bay-K-8644, amlodipine, nor verapamil had any effect on Ca2+ efflux. Nitrendipine at 20 microM modified neither the Km nor the Hill coefficient for Na+, whereas the Vmax was reduced to 2.9 nmol 45Ca2+ min-1 mg-1, thus demonstrating noncompetitive modulation of the Na+/Ca2+ exchanger. None of the Ca2+ channel-acting drugs assayed at 100 microM affected Ca2+ influx through the uniporter. Ca2+ channel blockers inhibited the Na+/Ca2+ antiporter and displaced the specific binding of [3H]nitrendipine to intact mitochondria with Ki values similar to the IC50s obtained for the inhibition of the Ca2+ efflux. Ca2+ channel-acting drugs that did not inhibit the Na+/Ca2+ exchanger (amlodipine, CGP 28392, Bay-K-9644, and verapamil, at concentrations of 100 microM or higher) had no effect on [3H]nitrendipine binding. These results suggest that the adrenomedullary mitochondrial dihydropyridine receptor is associated with the Na+/Ca2+ exchanger.     

Lymphocyte response to silica among offspring of silicone breast implant recipients

The current study evaluated immune response to silicon dioxide in children born to women with silicone breast implants. In part one of the study, the T lymphocytes of 21 of 24 such children were significantly stimulated by silicon dioxide (silica). Part two consisted of eleven children, four born preimplantation and seven born postimplantation. None of the preimplant offspring showed T cell responses to silica; five of the seven postimplant children were positive for T cell memory for silica. Part three was a blinded study based on statistically significant differences in T cell stimulation with silicon dioxide between postimplant children and controls. These findings indicate a common immune reaction, that of T cell memory, occurs in mothers and their children born after exposure to silicone mammary implants placed prior to pregnancy. Since not all such children were breast fed the result favors transplacental passage of immunogens such as silicone oligomers or through maternofetal cellular traffic.     

Curcumin induces apoptosis in immortalized NIH 3T3 and malignant cancer cell lines

Curcumin, which is a widely used dietary pigment and spice, has been demonstrated to be an effective inhibitor of tumor promotion in mouse skin carcinogenesis. We report that curcumin induces cell shrinkage, chromatin condensation, and DNA fragmentation, characteristics of apoptosis, in immortalized mouse embryo fibroblast NIH 3T3 erb B2 oncogene-transformed NIH 3T3, mouse sarcoma S180, human colon cancer cell HT-29, human kidney cancer cell 293, and human hepatocellular carcinoma Hep G2 cells, but not in primary culture of mouse embryonic fibroblast C3H 10T1/2, rat embryonic fibroblast, and human foreskin fibroblast cells in a concentration- and time-dependent manner. Many cellular and biochemical effects of curcumin in mouse fibroblast cells have been reported, such as inhibition of protein kinase C (PKC) activity induced by phorbol 12-myristate 13-acetate treatment, inhibition of tyrosine protein kinase activity, and inhibition of arachidonic acid (AA) metabolism. Treatment of NIH 3T3 cells with the PKC inhibitor staurosporine, the tyrosine kinase inhibitor herbimycin A, and the AA metabolism inhibitor quinacrine induces apoptotic cell death. These results suggest that, in some immortalized and transformed cells, blocking the cellular signal transduction might trigger the induction of apoptosis.     

Accidental hypothermia: incidence, risk factors and clinical course of patients admitted to hospital

This study was initiated to identify the incidence, risk factors and outcome predictors of patients admitted to hospital in the Netherlands because of accidental hypothermia. Information about these patients was available for study through the National Health Care Data Bank. Between 1987 and 1990, 612 accidental hypothermic patients were admitted: 185 hypothermic patients also suffered from submersion (HYPSUBS), but this was not the case in the remaining 427 patients (HYPNOTSUBS). Patients in the HYPNOTSUBS group were older (average age 55.2 years versus 38.9 years; p < 0.001), remained longer in hospital (average 20.8 days versus 9.2 days; p < 0.001) and had a higher death rate than those in the HYPSUBS group (16.9% versus 5.9%; p < 0.001). In HYPNOTSUBS, increasing age correlated with increases in the length of hospital stay and death rate. This relationship was not found in HYPSUBS. Trauma was the major associated problem in both groups; these patients had the highest death rate (22.8% versus 16.7%; not significant). Death occurred within 2 days in 54% of HYPNOTSUBS non-survivors and 73% of HYPSUB non-survivors. HYPNOTSUBS admitted to university hospitals showed a lower death rate (5.9%) compared with HYPNOTSUBS admitted to non-university hospitals with less than 400 beds (13.4%) or more than 400 beds (21.7%). In contrast, the death rate in HYPSUB was higher in university hospitals (14.3%) than in non-university hospitals with less than 400 beds (5.2%) or more than 400 beds (3.6%). We observed that the incidence of accidental hypothermia is low at 1.1 per 100,000 inhabitants per year. We concluded that HYPNOTSUBS and HYPSUB are different groups of patients with respect to demographic data, risk factors and prognostic factors. Old age is an important unfavourable prognostic factor in HYPNOTSUB but not in HYPSUB. Hypothermia with trauma is an unfavourable combination in both groups. Almost half of the HYPNOTSUBS non-survivors died after more than 2 days. Because body temperature will have returned to normal by then, this must be the result of late complications. Most HYPSUB non-survivors died during the first 2 days, probably as a direct result of the submersion injury.