Pulmonary surfactant activity after severe steam inhalation injury in rabbits

Lung water content, Pao2, surface tension (in terms of hysteresis) and lecithin content of both bronchial irrigation fluid and lung homogenates were determined after severe steam inhalation injury in rabbits. At the time of a decrease in Pao2 and an increase in lung water content there was a moderate fall in pulmonary surfactant activity; as shown by a progressive decrease in the area of the hysteresis loop and a decrease of the lecithin content in both bronchial irrigation fluid and lung homogenate. It is proposed that a fall in pulmonary surfactant activity plays an important role in the pathogenesis of pulmonary oedema after inhalation injury. Successive determinations of lecithin content and/or surface tension of bronchial irrigation fluid are recommended as early diagnostic and prognostic aids in severe inhalation injury.

Human chromosome hot points. IV. Uridine-induced hot-point breaks at 3p14 and 16q23-24 and increased expression of fragile site Xq27 in folate-free medium

Peripheral lymphocytes from 16 healthy adults, 9 pregnant women, and 3 fragile X syndrome patients were cultured in Eagle's minimum essential medium without folic acid (MEM-FA). The addition of 2 mM, 4 mM, or 8 mM uridine 24 h or 72 h prior to harvest resulted in increases of chromosome gaps or breaks, especially at hot points 3p14, 16q23-24, and at fragile site Xq27. Pregnant women showed higher frequencies of 3p14 breaks and total chromosome breaks than men and non-pregnant women. The other chromosome regions, such as 6q26, 7q23, 7q35, 6p25, Xp22, 14q23 and 11p13, also frequently showed gaps or breaks. The results indicated that the unbalance of nucleotide pools was one of the causes of chromosome breakages. The higher frequencies of chromosome gaps and breaks under the condition of thymidylate stress may be due to the misincorporation of uracil instead of thymine into DNA.

Histopathological and ultrastructural change in liver tissue from burned patients

Histopathological studies were made on samples of liver and spleen tissue taken post mortem from 59 patients with severe burns. Samples from 8 patients were also studied using the transmission electron microscope. The main pathological findings were degeneration and necrosis of hepatic cells and proliferation of Kupffer cells showing active phagocytosis. Their causes in relation to the time of death after burning and severity of injury have been discussed. The proliferation of Kupffer cells may be a compensatory reaction to the severe splenic injury seen in the patients.

Anaerobic infections of burns

From August 1980 to June 1982, 102 burn wound specimens taken from 34 patients were studied for anaerobic cultures. Fifteen instances (14.7 per cent) from 8 patients were positive and altogether 12 species were found. The predominant anaerobes were Bacteroides melaninogenicus, Peptococcus, Bacteroides fragilis, and other strains of Bacteroides and Peptostreptococcus. They were mostly discovered in electric burn wounds and burn wounds affecting the perianal and oral areas. Wounds with anaerobic infection usually appeared gaseous, necrotic and ischaemic with foul odour. Nineteen blood samples from 10 burn patients were also studied for anaerobic cultures, and two were positive, one caused by Bacteroides and the other by mixed infection of Peptococcus and Serratia, indicating that the anaerobes played an important role in burn infections. It seems necessary to perform anaerobic culture studies in burn patients as a routine. A comparative study between anaerobic culture and indirect immuno-fluorescence method was undertaken for Bact. fragilis and Bact. melaninogenicus in 47 burn wounds. It showed that the immunofluorescence method was a more rapid, simple, sensitive and specific diagnostic method.

Human chromosome hot points. 1. Hot point at 3p14 in three populations

A chromosome hot point, 3p14, in healthy peasants, mentally retarded patients (MR), and epileptic patients (EP) was studied. The frequency of the hot point, 3p14 break, was significantly higher in EP. It may be caused by folic acid reduction in patients' serum induced by the antiepileptic drugs. The difference between hot point and fragile site is discussed.

Identification of a new glutathione S-transferase from rat liver cytosol

A new glutathione S-transferase has been purified to homogeneity from 105,000 X g supernatant of Sprague-Dawley rat liver homogenates. The purified enzyme exhibited specific activities of approximately 1.8, and 0.12 mumoles X min-1 X mg-1 toward 1-chloro 2,4-dinitrobenzene and cumene hydroperoxide respectively. The SDS gel electrophoresis data on subunit composition revealed that the new transferase is composed of two subunits with an identical Mr of 24,400 (Y alpha Family). Our in vitro translation experiments with rat liver poly(A) RNAs and substrate specificity data suggest that this subunit is different from the previously reported Ya , Yb and Yc subunits of rat liver glutathione S-transferases. Comparatively, the new isozyme showed significant activity toward 1,2 epoxy-3-(P-nitrophenoxy)-propane, ethacrynic acid and P-nitrophenyl acetate, 0.4, 0.34 and 0.18 mumoles. min-1 X mg-1 respectively.

The nucleotide sequence of a rat liver glutathione S-transferase subunit cDNA clone

We have determined the nucleotide sequence of a cloned cDNA derived from liver poly(A) RNA of pentobarbital-treated rats encoding a glutathione S-transferase subunit. This cDNA clone pGTR261 contains one open reading frame of 222 amino acids, a complete 3' noncoding region, and 63 nucleotides in the 5' noncoding region. The cloned DNA hybridizes to rat poly(A) RNA in a tissue-specific fashion, with strong signals to liver and kidney poly(A) RNA(s) of approximately 1100 and approximately 1400 nucleotides in size but little or no hybridization to poly(A) RNAs from heart, lung, seminal vesicles, spleen, or testis under stringent conditions. Our sequence covers the cDNA sequence of pGST94 which contains a partial coding sequence for a liver glutathione S-transferase subunit of Ya size. Comparison of sequences with our earlier clone pGTR112 suggests that there are at least two mRNA species coding for two different subunits of the Ya (Mr = 25,600) subunit family with very limited amino acid substitutions mainly of conserved polarity. The divergent 3' noncoding sequences should be useful molecular probes in differentiating these two different but otherwise very similar subunits in induction and genomic structure analyses. Our results suggest that tissue-specific expression of the glutathione S-transferase subunits represented by the sequences of pGTR261 and pGTR112 may occur at or prior to the level of RNA processing.

Effect of intravenous infusion on development of pulmonary oedema after inhalation injury

Last year, after a systematic search of pathological and patho-physiological changes of inhalation injury in dogs, we recorded severe pulmonary oedema as early as 2 h postburn (the earliest monitoring time designed in experiment) on dogs inflicted with both body surface and severe respiratory burns without any fluid replacement during the whole course of experiment. In an analysis of cases admitted into our burn centre in the past ten years, we also found that there was no definite relationship between the incidence and severity of pulmonary oedema occurring in severe burn patients and the amount of fluid infused in the early burn phase. These facts led us to the following experiment designed to study the effect of intravenous infusion on development of pulmonary oedema after severe burns complicated with inhalation injuries.