Diagnosis and treatment of cannula-related intravenous sepsis in burn patients

Suppurative thrombophlebitis was identified in 193 (4.2%) of 4,636 burn patients treated during the years 1960-1978. A single vein was involved in 162 patients, while 31 had multiple vein involvement. The distribution and incidence of suppuration in individual veins reflected the frequency of cannulation, with an increase in the use of central vein cannulae, during the last 10 years, paralleled by a rise in central vein suppuration. The infecting organisms reflected the patients' surface flora. Local signs of infection were present in less than half (35%) of the patients and recovery of a positive blood culture in a clinically septic patient was the most frequent clinical presentation prompting exploration of previously cannulated veins. Pathogenetic mechanisms are identified and criteria defined for determining the extent of excision necessary. Ninety veins were excised from 75 patients during the 1969-1978 period, of whom 30 (40%) survived (three other patients with antibiotic treated central vein disease also survived). Treatment failure was attributable to inadequate excision in 12 patients, suppuration within another unexcised vein in eight patients, hematogenous dissemination of infection in five patients in whom the local disease had been eradicated, and other disease in 20 patients. Prophylaxis must emphasize limited duration of cannulation. Timely diagnosis and treatment can effect maximum salvage and reduce the likelihood of systemic dissemination.

Structural analogues of L-glutamic Acid gamma-(4-hydroxyanilide) and gamma-(3,4-dihydroxyanilde) as potential agents against melanoma

Nine heretofore unknown mono- and dihydroxyanilide analogues of the cytotoxic mushroom metabolites L-glutamic acid gamma-(4-hydroxyanilide) (1) and L-glutamic acid gamma-(3,4-dihydroxyanilide) (3, agaridoxin) were synthesized and tested as inhibitors of the growth of B16 mouse melanoma cells in culture. The naturally occurring anilides 1 and 3 had ID50 values of 0.10 and 0.27 mM, respectively. The analogue of 1 in which the gamma-L-glutamyl moiety was replaced by beta-L-aspartyl showed only a threefold decrease in activity, whereas attachment of the phenolic OH group to the meta instead of the para position resulted in a tenfold decrease. Other structural modifications, such as O-methylation or deletion of the carboxyl or amino group in the side chain, led to compounds of still lower activity (ID50 greater than 1.0 mM). The only analogue in the series with more activity than either 1 or 3 against B16 cells was L-glutamic acid gamma-(2,5-dihydroxyanilide) (14), which had an ID50 value of 0.051 mM. These data suggest that the gamma-L-glutamyl side chain in 1 or 3 plays a significant role in the biological action of these compounds, though some flexibility appears to exist insofar as the positioning of OH groups on the aromatic ring is concerned.

Imidazo[1,2-a]-s-triazine nucleosides. Synthesis and antiviral activity of the N-bridgehead guanine, guanosine, and guanosine monophosphate analogues of imidazo[1,2-a]-s-triazine

The first chemical synthesis of 2-aminoimidazo[1,2-a]-s-triazin-4-one (8), the corresponding nucleoside and nucleotide, and certain related derivatives of a new class of purine analogues containing a bridgehead nitrogen atom is described. Condensation of 2-amino-4-chloro-6-hydroxy-s-triazine (2) with aminoacetaldehyde dimethyl acetal followed by the ring annulation gave the guanine analogue 8. A similar ring annulation of 4-(2,2-dimethoxyethylamino)-s-triazine-2,6-dione (5) gave imidazo[1,2-a]-s-triazine-4,6-dione (9). Direct glycosylation of the trimethylsilyl derivative of 8 with 1-O-acetyl-2,3,5-tri-O-benzoyl-beta-D-ribofuranose in the presence of stannic chloride, followed by debenzoylation, gave the guanosine analogue 2-amino-8-(beta-D-ribofuranosyl)imidazo[1,2-a]-s-triazin-4-one (12b), which on deamination gave the xanthosine analogue 13. Phosphorylation of 12b gave 2-amino-8-(beta-D-ribofuranosyl)imidazo[1,2-a]-s-triazin-4-one 5'-monophosphate (II). The anomeric configuration has been determined unequivocally by using NMR of the 2',3'-O-isopropylidene derivate 10 and the site of ribosylation has been established by using 13C NMR spectroscopy. These compounds were tested against type 1 herpes, type 13 rhino, and type 3 parainfluenza viruses in tissue culture. Moderate rhinovirus activity was observed for several compounds at nontoxic dosage levels.

Selective potentiation of hyperthermic killing of hypoxic cells by 5-thio-D-glucose

The modification of cell lethality at elevated temperatures by 5-thio-D-glucose, the nearest analog of D-glucose was studied with the use of HeLa cells in the presence or absence of oxygen. When the cells were exposed to temperatures ranging from 40.5-42 degrees for 0.5 to 4 hr in the presence of 5-thio-D-glucose (5 mM), there was a selective potentiation of hyperthermic killing of hypoxic cells. No enhanced killing of oxic cells by 5-thio-D-glucose was seen at these temperatures. These results indicate that glucose metabolism may be involved in influencing the heat sensitivity of hypoxic cells. The low toxicity of 5-thio-D-glucose and its specificity to hypoxic cells suggest that it may be a useful adjuvant to hyperthermic therapy.

5-Thio-D-glucose selectively potentiates hyperthermic killing of hypoxic tumor cells

To investigate the mechanisms by which heat affects cancer cells, we used 5-thio-D-glucose, an inhibitor of glycolysis in HeLa S-3 cells, under aerobic and hypoxic conditions at temperatures ranging from 37 degrees to 43 degrees C. Drug alone or heat alone killed a minimum number of cells under aerobic or hypoxic conditions. Exposure to drug and hyperthermia selectively increased the number of cells killed under hypoxic conditions at temperatures as low as 40.5 degrees C but had little effect on cells incubated under aerobic conditions. These results suggest that the glycolytic pathways is a primary site of hyperthermic damage leading to cell death.

alpha-Helix-double helix interaction shown in the structure of a protamine-transfer RNA complex and a nucleoprotamine model

Single crystal X-ray diffraction and circular dichroism studies of protamine binding to a tRNA suggest that the protamine molecule changes its conformation from a random coil to a structure containing a helices on binding to tRNA, and that alpha-helical segment(s) of protamine bind approximately along a shallow groove of a double-helical portion of ttrna. based on these observations, a structural model for nucleoprotamine is proposed.

Sexual precocity in a male due to thoracic polyembryoma

A 7-year-old boy with sexual precocity of recent onset was found to have elevated levels of chorionic gonadotropin, alpha fetoprotein, and testosterone. Removal of a retropleural, posterior mediastinal mass with an intraspinous epidural extension was followed by prompt declines in the plasma concentrations of the tumor markers and cessation of adolescent development. The neoplasm proved to be a polyembryoma, unusual in the multiplicity of its embryoid bodies and extra gonadal location. Following local irradiation and two years of systemic chemotherapy, the patient, now 13 years of age, has done well except for evidence of testicular tubular insufficiency.

Effect of dietary restrictions and source of rats on growth rate and efficiency of conversion of food into muscles, bones and organs

Differences in weight of the body, six different skeletal muscles, epididymal fat pads, three different bones, spleen, heart, kidneys, testes and liver were observed in 21-day-old male Sprague-Dawley rats from two different suppliers. All rats were pair-fed a 10% casein diet ad libitum, 10%, 20%, 30% restricted for 4 or 8 weeks. Original body and tissue weight differences between the two strains of rats were maintained in all diets during the 4 and 8 week feeding periods. Trends in body and tissue weight changes due to dietary restriction were similar in both strains of rats. Diet restrictions for 4 or 8 weeks caused similar patterns of weight decrease in most tissues. Feed efficiency ratio (FER) was reduced significantly at the 20% and 30% restriction for 4 weeks only in the lighter strain of rats. FER was higher in the heavier strain than in the lighter strain of rats at all levels of diet restriction. Food conversion efficiency with reduced food intake was constant or decreased depending on the skeletal muscle studied; decreased significantly for epididymal fat pad, bone weight (one strain only), kidneys and liver (one strain only) with the 30% reduced diet for 4 weeks; and increased for bone length and testes weight. Therefore, significant deviations from ad libitum controls were found only at 30% diet restriction, and the wide differences in body and tissue weight of two strains of Sprague-Dawley rats did not affect the interpretation of results when fed the same restricted diets.

RNA-ligant interactions. (I) Magnesium binding sites in yeast tRNAPhe

X-ray crystallagraphic studies studies indicate that there are at least four site-specifically bound hydrated Mg2+ ions, [Mg(H2O)n]2+, in yeast tRNAPhe. The size and the octahedral coordination geometry, rather than the charge, of [Mg(H2O)N]2+ appear to be the primary reasons for the specificity of magnesium ions in site-binding and in the stabilization of the tertiary structure of tRNA.

Secondary structural complementarity between DNA and proteins

A model for the complex between double-stranded DNA and a beta-ribbon (a two-stranded antiparallel beta-sheet) of proteins is proposed as one of the possible modes of structural recognition between DNA and proteins. In this model, the contact occurs on the narrow groove of DNA, and the symmetry elements as well as the repeat distances of DNA and the beta-ribbon coincide, thus providing favorable complementary contacts.

Endoscopic resection of obstructing airway lesions in children

In the past 8 yrs, 14 children were treated with obstructing lesions of the larynx, some of then acquired from prolonged intubation. Endoscopic resection of the obstructions proved feasible in selected cases. The use of a wire stylette of fine needle within a small ureteral catheter sheath provides a readily available and accurate means for dealing with some of these lesions.

Omphalocele

From a historical curiosity at the turn of the century, today omphalocele and gastroschisis can be corrected with good results, thanks to innovative techniques and better understanding of the newborn. Associated anomalies consist mainly of malrotation, Meckel's diverticulum, intestinal atresia, congenital heart defects, and genitourinary abnormalities. Nonoperative management in certain centers has been sucessful for the very large omphaloceles with an intact sac; however, a secondary procedure is necessary. In the past 10 years, the use of Silastic sheeting and total parenteral nutrition has allowed early repair of even the most severe cases, with excellent end results and low mortality.