Effects of lactate on intracellular pH and hypercontracture during simulated ischemia and reperfusion in cardiac ventricular myocytes of the guinea pig.

Effects of lactate on changes in intracellular pH (pHi) and contractility during simulated ischemia and reperfusion were examined in single myocytes of the guinea pig cardiac ventricle. The conditions of simulated ischemia were produced by the exchange of perfusion medium from the standard one oxygenated with 95% O2-5% CO2 gas (pH 7.4) to one containing no glucose, 8 mM K+, and 0-30 mM sodium-D,L-lactate and was gassed with 90% argon - 10% CO2 (pH 6.6). The pHi was decreased by the simulated ischemia from approx. 7.3 to approx. 6.9 regardless of lactate concentration, while the rate of pHi decrease was increased by lactate in a concentration-dependent manner. The contraction induced by electrical stimulation disappeared faster in the presence of lactate. The incidence of irreversible hypercontracture of myocytes was significantly reduced by 20-30 mM lactate. The overshoot of pHi to approx. 7.7 and excess contractions were induced by withdrawal of lactate during the reperfusion, but not observed when lactate was continuously present. The recovery of normal contractility during reperfusion was facilitated by lactate. It can be concluded that lactate added to or removed from the perfusion medium increases the rate of pHi change under the simulated ischemia and reperfusion, respectively, and that the continuous presence of lactate reduces cell injury under these conditions.     

Droperidol inhibits tracheal contraction induced by serotonin,histamine or carbachol in guinea pigs

Purpose

Droperidol (D) is effective in the treatment of patients with status asthmaticus. It has been reported that D inhibits the bronchoconstriction induced by serotonin (5-HT) but not that by histamine (H) or acetylcholine. However, haloperidol, another butyrophenone, is known to interact with and inhibit calmodulin, an intracellular Ca⁺⁺-binding protein which is important in the contraction of smooth muscles. The present study was designed to investigate the effects of D on tracheal contractions induced by 5-HT, H or carbachol (C) and to determine the contribution of α-adrenoceptors to the relaxant effect of D in vitro.

Methods

Tracheas of female guinea pigs were cut spirally into strips and mounted in water-jacketed organ baths in Tyrode’s solution, aerated with a mixture of 95% O₂ and 5% CO₂ at 37°C. The changes in isometric tension induced by each spasmogen in the strips were measured with a transducer and a polygraph.

Results

We found that D inhibited the tracheal contractions induced by 5-HT, H or C in a concentration-dependent manner. At 1.25 × 10^?6 M D blocked the effect of 10^?4 M 5-HT by 44.1 ± 4.3% and at 2.5 × 10^?6 M by 63.8 ± 3.8%. Similarly, at 5.0 × 10^?6 M concentration, D blocked the effect of 10^?5 M H by 27.7 ± 5.3% and at 10^?5 M by 56.2 ± 2.6%. Furthermore, 5 ×10^?6 M of D reduced the contractions produced by 10^?7 M C by 37.1 ± 3.0% and 70^?5 M of D by 76.1 ± 3.2%. The inhibiting effect of D was strongest on contractions induced by 5-HT. Prazosin (70^?6 M) affected neither 5-HT-induced contractions nor the inhibition by D.

Conclusion

Our data indicate that D partially blocks the contractile responses not only to 5-HT, an effect which would be mediated through a blockade of the 5-HT receptors, but also to H or C, probably through inhibition of calmodulin. Our data support previous reports indicating that droperidol may be an important therapeutic agent in the treatment of patients with hyperreactive airways.     

Day surgery for treatment of varicose veins in the leg

We had surgically treated varicose veins in 554 legs of 386 patients as of June 30, 2000. Varicose veins of the stem or segment type without skin changes were treated with sclerotherapy combined with high ligation, while a part of secondary varicose veins and the reticular or web type were treated with sclerotherapy alone. This paper describes our methods for day surgery for this condition. The most important therapeutic consideration in the surgical procedure is achieving sufficient venous collapse to prevent the occurrence of intravenous thrombus. In our 386 patients, a massive intravenous thrombus that was resected occurred in one limb (0.1%). Postoperative bleeding also occurred in one limb (0.1%) of a patient with severe liver cirrhosis.     

Sequence Analysis of Genes Encoding Rodent Homologues of the Human Tumor-rejection Antigen SART-1

Human SART-1 ( hSART-1 ) gene encodes a 125 kD protein with a leucine-zipper motif expressed in the nucleus of all proliferating cells, and a 43 kD protein expressed in the cytosol of most epithelial cancers. In this study, two rodent genes ( rSART-1 and mSART-1 ) homologous to hSART-1 were cloned from cDNA libraries of murine brain and a rat tumor cell line, respectively. mSART-1 and rSART-1 were highly homologous to hSART-1 with 86% and 84% identity at the nucleotide level, and 95% and 91% at the protein level, respectively. The leucine zipper domain and two basic amino acid portions that bind DNA, as well as peptide sequences recognized by human cyto-toxic T lymphocytes (CTLs), were all conserved in these rodent genes. Nuclear protein homologous to the 125 kD hSART-1₈₀₀ protein, but not to the 43 kD cytosol SART-1₂₅₉ protein, was detectable with specific antibody in the nuclear fractions of rodent tumor cell lines, and normal rodent fetal liver and testis. These rodent genes should be a novel tool for studies on the biological roles of the SART-1 gene, and also in the construction of animal models of specific immuno-therapy using SART-1 gene products.     

Characterization of mouse Ire1 alpha: cloning, mRNA localization in the brain and functional analysis in a neural cell line

In yeast, an endoplasmic reticulum (ER)-associated protein, Ire1p, is believed to initiate the unfolded protein response (UPR), that is responsible for protein folding in the ER under stressed conditions. Two mammalian homologs of Ire1p have been identified, Ire1 alpha and Ire1 beta. We have previously reported that familial Alzheimer's disease linked presenilin-1 variants downregulate the signaling pathway of the UPR by affecting the phosphorylation of Ire1 alpha. In the present study, we cloned the mouse homolog of Ire1 alpha for generating genetically modified mice. Ire1 alpha was ubiquitously expressed in all mouse tissues examined, and was expressed preferentially in neuronal cells in mouse brain. This led us to investigate the effects of the downregulation of the UPR on the survival of neuronal cells under conditions of ER stress. Morphological and biochemical studies using a dominant-negative form of mouse Ire1 alpha have revealed that cell death caused by ER stress can be attributed to apoptosis, and that the downregulation of the UPR enhances the apoptotic process in the mouse neuroblastoma cell line, Neuro2a. Our results indicate that genetically modified mice such as transgenic mice with a dominant-negative form of Ire1 alpha might provide further understanding of the pathogenic mechanisms of Alzheimer's disease and other neurodegenerative disorders.     

Serine protease inhibitors prevent alcoholic liver injury]

The hepatotoxic effects of alcohol have been described in detail, but factors responsible for its hepatotoxicity have only partially characterized. It now appears that Kupffer cell derived TNF-alpha participates in several aspects of alcoholic liver injury. On the other hand, protease inhibitors have been used successfully for treatment of intractable diseases in which TNF-alpha is involved in the pathogenesis, including ulcerative colitis and Crohn's disease. Here, we will review new evidence for the proposal that serine protease inhibitors prevents alcoholic liver injury via mechanisms dependent on Kupffer cell derived TNF-alpha.     

A case of anaphylaxic shock due to latex glove used on internal examination and on the probe of intrauterine echogram

A 15 year old female with uterus bicornis bicollis was admitted for operation. She had a history of atopic dermatitis and allergy to buckwheat, raw egg and latex. Two months previously she had developed whole body flushing during dental treatment, and latex glove used by the dentist had been suspected as the cause. Prior to the operation she underwent internal examination and intrauterine echogram in which a latex glove was carelessly used by another gynecologist who had not confirmed her past history. After 30 minutes, dyspnea and urticaria without itching, appeared suddenly. Blood pressure decreased to 80/50 mmHg and heart rate increased to 120 beats.min-1. She was then transferred to our ICU. Methylprednisolone was administered intravenously for dyspnea and circulatory collapse. After 3 hours, the patient made an uneventful recovery. The increased plasma latex protein-specific IgE levels confirmed anaphylaxis to latex. The increasing incidence of potentially life-threatening allergic reactions to latex has caused mounting concern over recent years. We may suspect latex allergy when an anaphylaxic reaction or shock of unknown origin occurs. In hospitals, latex free products must be prepared for use with latex allergic patients and for protection of medical staff with this allergy.