Expression of inducible nitric oxide synthase in human burn wounds

A water-soluble synthetic peptide with only nine amino acid residues, comprising the 131-139 sequence region of the cytotoxic protein alpha-sarcin (secreted by the mold Aspergillus giganteus), interacts with large unilamellar vesicles composed of acid phospholipids. It promotes lipid mixing between bilayers and leakage of vesicle aqueous contents, and it also abolishes the phospholipid phase transition. Other larger peptides containing such an amino acid sequence also produce these effects. These peptides acquire alpha-helical conformation in the presence of trifluoroethanol, but display beta-strand conformation in the presence of sodium dodecyl sulfate. The interaction of these peptides with the lipid vesicles also results in beta-structure. The obtained data are discussed in terms of the involvement of the 131-139 stretch of alpha-sarcin in its interaction with lipid membranes.     

Transgenic animal models for the functional analysis of vasoactive peptides

The interplay of vasoactive peptide systems is an essential determinant of blood pressure regulation in mammals. While the endothelin and the renin-angiotensin systems raise blood pressure by inducing vasoconstriction and sodium retention, the kallikrein-kinin and the natriuretic-peptide systems reduce arterial pressure by eliciting vasodilatation and natriuresis. Transgenic technology has proven to be very useful for the functional analysis of vasoactive peptide systems. As an outstanding example, transgenic rats overexpressing the mouse Ren-2 renin gene in several tissues become extremely hypertensive. Several other transgenic rat and mouse strains with genetic modifications of components of the renin-angiotensin system have been developed in the past decade. Moreover, in recent years gene-targeting technology was employed to produce mouse strains lacking these proteins. The established animal models as well as the main insights gained by their analysis are summarized in this review.     

The effect of combined external beam radiotherapy and brachytherapy on local control and wound complications in patients with high-grade soft tissue sarcomas of the extremity with positive microscopic margin

PURPOSE: A previously reported randomized trial from out institution demonstrated a local control advantage to adjuvant brachytherapy (BRT) for completely resected high grade soft tissue sarcoma (STS). In recent years, BRT boost has been combined with wide field external beam radiotherapy (EBRT) for selected patients in whom the margin(s) of resection was positive. This study evaluates the impact of BRT boost plus EBRT on local control in this subset of patients and on wound complication rates. METHODS AND MATERIALS: Between January, 1987 and December, 1992, 105 adult patients with primary or locally recurrent high grade STS of the extremity were treated with wide local excision and BRT alone (87 patients; dose: 45 Gy) or BRT plus EBRT (18 patients; dose: 15-20 Gy BRT + 45-50 Gy EBRT). The margin(s) of resection was positive in 10 out of 18 patients in the BRT + EBRT group vs. 17 out of 87 patients in the BRT alone group. Wound complications were classified as major if they required further operative intervention; moderate if there was purulent discharge, hematoma > 25 ml, wound separation > 2 cm, and persistent seroma requiring drainage; or minor if less than moderate. Median follow-up was 22 months. RESULTS: The overall 2-year actuarial local control rate was 86%. There was no difference in the 2-year actuarial local control rate between the BRT + EBRT group (90%) and the BRT alone group (82%) (9 = 0.32). However, for patients with positive resection margins the use of BRT + EBRT produced better local control than BRT alone [9 out of 10 (90%) vs. 10 out of 17 (59%)]. This difference approached but did not reach statistical significance (p = 0.08). No difference was seen in patients with negative margins. There was no significant difference in the overall wound complication rate (26% BRT vs. 38% BRT + EBRT, p = 0.31) nor in the combined major and moderate wound complication rate (16% BRT vs. 27% BRT + EBRT, p = 0.39). CONCLUSION: Our preliminary data suggest a trend in favor of BRT boost + EBRT as the optimal adjuvant local strategy for STS with positive resection margins. There is no significant difference in the wound complication rate with either technique.     

A method for rapid filling of fine-tipped micropipettes with electrolyte solutions including those containing horseradish peroxidase

Cooling the tips of micropipettes pulled from filament-containing capillary glass dramatically increases the rate and completeness of filling with a variety of electrolyte solutions. In tests with solutions containing horseradish peroxidase this method increased the completeness of filling by more than two orders of magnitude.     

Tissue and plasma peptidase activity is altered during hypothermic hibernation in the 13 lined ground squirrel (Spermophilus tridecemlineatus)

Adult 13 lined ground squirrels were monitored for entry into a state of hypothermic hibernation or arousal in a cold room on a photoperiod LD 2:22. Once animals developed predictable hibernation patterns, animals were killed at the mid point of hypothermic hibernation or arousal for determination of plasma and tissue angiotensin-1-converting enzyme (Kininase II) activity. Enzyme was extracted from plasma, lung, kidney, liver, forebrain and brainstem and assayed in vitro. During hypothermic hibernation enzyme activity is significantly decreased in all tissues examined. These data suggest that the activity of tissue and plasma peptidases are altered during the cyclic torporous periods characteristics of hibernation in this species.     

Effects of cytosine arabinoside on human leukemia cells

Cytosine arabinoside (Ara-C) is used to treat leukemias, with complete remission induced by combination chemotherapy in approximately 70% of cases of acute myelogenous leukemia (AML). Ara-CTP acts as a competitive inhibitor of DNA polymerase and may also be incorporated into DNA. Accumulation of deoxyribonucleoside triphosphates (dNTPs) induced by Ara-C may indicate disruption of DNA synthesis in susceptible leukemia cells. A procedure has been developed for the quantification of Ara-CTP and dNTPs from small samples of leukaemia cells from patients (4 x 10(7) cells) activated with concanavalin A (10 micrograms/ml, 48 hr) and grown in the presence of [32P]orthophosphate (1.1 microM, 9 x 10(6) Ci/mol, 16 hr). The susceptibilities to Ara-C of the human leukemia cell lines CCRF-CEM (IC50 = 6.30 nM), CCRF-HSB-2 (IC50 = 10.4 nM) and MOLT-4 (IC50 = 10.0 nM) may be correlated with their abilities to accumulate high concentrations of Ara-CTP (> 1000 amol/cell) with increases of between 1.3- and 3.4-fold in dATP, dGTP and dTTP for the four cell lines, while dCTP decreased between 0.23- and 0.78-fold. By contrast, an Ara-C-resistant derivative of HL-60 cells (IC50 = 400 nM) accumulated only low concentrations of Ara-CTP (71 amol/cell) without significant changes in dNTPs. High concentrations of Ara-CTP in leukemia cells induce accumulations of dATP, dGTP and dTTP due to inhibition of DNA synthesis, and depletion of dCTP. This imbalance in the pools of the four dNTPs could lead to genetic miscoding and cell death.     

Results of a policy of primary repair of truncus arteriosus in the neonate

Although the early mortality for repair of truncus arteriosus has decreased in the modern era, routine correction in the neonate has not been widely adopted. To assess the results of our protocol of early repair, we reviewed 46 neonates and infants undergoing repair of truncus arteriosus at the University of Michigan Medical Center from January 1986 to January 1992. Their ages ranged from 1 day to 7 months (median 13 days) and weights from 1.8 kg to 5.4 kg (mean 3.1 kg). Repair was performed beyond the first month of life in only 8 patients, because of late referral in 7 and severe noncardiac problems in 1. Associated cardiac anomalies were frequently encountered, the most common being interrupted aortic arch (n = 5), nonconfluent pulmonary arteries (n = 4), hypoplastic pulmonary arteries (n = 4), and major coronary artery anomalies (n = 3). Truncal valve replacement was performed in 5 patients with severe regurgitation, 3 of whom also had truncal valve systolic pressure gradients of 30 mm Hg or more. The truncal valve was replaced with a mechanical prosthesis in 2 patients and with a cryopreserved homograft in 3 patients. Right ventricle-pulmonary artery continuity was established with a homograft in 41 patients (range 8 mm to 15 mm), a valved heterograft conduit in 4 (range 12 mm to 14 mm), and a nonvalved polytetrafluoroethylene tube in the remaining patient (8 mm). There were 5 hospital deaths (11%, 70% confidence limits 7% to 17%). Multivariate and univariate analyses failed to demonstrate a relationship between hospital mortality and age, weight, or associated cardiac anomalies. Only 1 death occurred among 9 patients with interrupted aortic arch or nonconfluent pulmonary arteries. Hospital survivors were followed-up from 3 months to 6.3 years (mean 3 +/- 0.4 years). Late noncardiac deaths occurred in 3 patients, all within 4 months after the operation. Actuarial survival was 81% +/- 6% at 90 days and beyond. Despite the prevalence of major associated conditions, early repair has resulted in excellent survival. We continue to recommend repair promptly after presentation, optimally within the first month of life.     

Anterior choroidal artery aneurysm and stroke

We report the unique combination of a mid anterior choroidal artery (AChA) aneurysm and ischemic stroke presenting as a movement disorder in a young man. The mechanism for stroke in the AChA territory may either reflect a cause or an effect of aneurysm formation. We provide evidence for both arguments and speculate on the anatomic basis for the initial presentation of hemibody spasm.