Characterization of the human c-K-ras gene promoter

The promoter of the human c-K-ras gene has been characterized by deletion mutagenesis in concert with stable and transient expression gene transfer experiments. The transcription initiation sites were determined by S1 mapping and RNase A protection experiments. The c-K-ras promoter region is rich in G + C, lacks TATA and CCAAT boxes and contains sequence similarities with other house-keeping genes such as the dihydrofolate reductase (DHFR) and the epidermal growth factor (EGF) receptor genes. The promoter of the c-K-ras gene consists of multiple elements and initiation of transcription occurs at multiple sites. A 54 bp DNA fragment immediately upstream from the 5' end untranslated exon controls the position of many of the transcription initiation sites and direct sufficient transcription for transformation of NIH3T3 cells. However, these sequences can be replaced by other upstream sequences which are required for optimal gene expression. In addition, sequences overlapping with the 5' end untranslated exon and therefore downstream from the major transcription initiation sites are important (although not sufficient) for transcription because their deletion greatly impairs the promoter activity of the upstream elements.

[A new surgical method for the creation of atrial septal defects]

For the creation of atrial septal defect (ASD), we have developed a new method (Method I) using modified Harken blade for the closed commissurotomy, in which the membranous septum of the fossa ovalis was incised in case of patent foramen ovale (PFO). When there was no or very narrow PFO, we applied Schuster's procedure to create defect in the muscular and membranous septum, however, it was sometimes found the bridging of remnant of membranous septum was left. So that, we have applied the Method I to cut it off (Method II). Up to date, eleven patients were operated with the Method I, and three patients with the Method II. As the results, nearly no pressure gradient between right and left atrium was detected postoperatively. In two cases, sufficiently created ASDs were confirmed at radical surgery. Because of the safety and reliability, our new procedures appear to be more advantageous in comparing to conventional Blalock-Hanlon or other procedures.

Evaluation of rapid drying hand disinfectant preparations in the intensive care unit

MK412A (0.2% chlorhexidine in 70% ethanol) and MK412B (0.2% benzalkonium chloride in 70% ethanol), which are rapid drying and rubbing antiseptic preparations, have been evaluated for hand sterilization over a month by ICU nurses. They have been shown to have effective skin decontaminant efficacy under practical conditions in a busy ICU. There were no adverse reactions except for two cases of mild erythema in the MK412A treatment group. In a comparative in vitro study with Pseudomonas cepacia, 0.2% chlorhexidine solution alone and 0.2% benzalkonium chloride solution alone were less bactericidal than MK412A and MK412B.

Effect of pre-adaptation on pattern electroretinogram (P-ERG)

Up to now light and dark adaptation are considered as of minor importance when recording the pattern electroretionogram (P-ERG) which in man reflects cone vision. In order to test this supposition transient P-ERGs were recorded in six healthy subjects to a reversing checkerboard pattern produced by a pivoted mirror system after two minutes of pre-exposure to darkness (1), to the pattern reversal stimulus (2), and to uniform illumination of 3.3 log cd/m2 (3). Field size was 18 x 20 degrees, check size 69 min of arc, reversal frequency 3.5/s, contrast 0.95. When recording the P-ERG within the first 30 s after pre-exposure, the amplitude/luminance function of the p-q and the q-r component was shifted along the luminance axis without changing the maximum amplitude. For a criterion response of 1.5 microV there was a sensitivity difference of 1.3 log units between measurements after pre-exposure to darkness and after strong illumination. Furthermore, the P-ERG latencies of the q and the r component displayed significantly shorter values after pre-exposure to strong light than after darkness, whereas no change of p-latency was recorded. We conclude that pre-exposure to darkness and strong illumination has no effect on the P-ERG elicited at high luminance levels. However, pre-adaptation should be considered when recording the P-ERG at luminance levels near threshold.

The c-K-ras gene and human cancer (review)

A significant number of human tumors from diverse histological origins contain c-K-ras oncogenes which have been activated by somatic point mutations resulting in single amino acids substitutions in the encoded p21 ras protein. In addition to these qualitative changes, other genetic alterations leading to increased expression of the c-K-ras gene, especially its mutated form, appear to be important in the activation of its oncogenic potential. These findings support the hypothesis that c-K-ras oncogenes are contributing in a dominant but dose dependent manner to the multistage process of human tumorigenesis. Activated c-K-ras oncogenes have been detected in human tumors at different stages of progression, including premalignant neoplasms. These studies provide evidence for the involvement of somatic mutational activation of this ras gene in the early stages of tumor development in some types of human cancer. We discuss here the structural and functional features of the human c-K-ras gene and the involvement of its activated form in human cancer.

Inactivation of influenza B virus by normal guinea-pig serum

Normal guinea-pig serum (GPS) lacking detectable antiviral antibody efficiently neutralized the infectivity of influenza B virus grown in chick embryos or MDCK cells. The inhibitor was heat-labile and sensitive to trypsin digestion. This beta-like inhibitor required Ca2+ and the complement components C1 and C4 for its activity. In contrast, GPS did not inactivate influenza A virus. Influenza B virus from which the neuraminidase activity of the spikes on the viral envelope had been eliminated by trypsin digestion was also inactivated to a level comparable to untreated virus. Complement component C1 alone bound directly to influenza B virus and inhibited its haemagglutinin activity. We suggest that the beta-like inhibitor in GPS is a component of the classical complement pathway which is triggered by the protein moiety of influenza B virus haemagglutinin, leading to virus neutralization.

Respiratory care of pediatric patients requiring prolonged intubation after cardiac surgery

Pediatric patients requiring intubation more than 4 days after cardiac surgery can experience many respiratory and other problems. We found that 48 of 264 pediatric patients could not be extubated within 4 days after open-heart surgery because PaO2 was less than 75 torr and PaCO2 was over 45 torr on an inspired oxygen fraction of 0.4. Most of the 48 patients were under 12 months old, had pulmonary hypertension and/or complex cardiac anomalies, and were not hemodynamically stable and/or fully conscious. The intensity of long-term intubation was attributed to cardiovascular or respiratory complications and multiple organ failure. At the time of extubation, water infusion was maintained below 80 ml/kg X day and positive water balance below 15 ml/kg X day. Calories and amino acid were maintained over 70 kcal/kg X day and 1.5 g/kg X day, respectively.

The neuronal pathway from the flocculus to the oculomotor nucleus: an electrophysiological study of group y nucleus in cats

In 17 cats anesthetized by Ketalar, neuronal activities were recorded extracellularly by a tungsten microelectrode placed in the group y nucleus of the vestibular nuclei. Forty-seven of 139 neurons tested were activated antidromically by stimulation of the superior rectus and inferior oblique subdivisions of the oculomotor nucleus. Twenty-five of these 47 neurons ceased their spontaneous discharges after stimulation of the caudal zone of the flocculus. In addition, 18 out of these 25 units responded polysynaptically to stimulation of the vestibular nerve.

[Efficacy and limitation of postoperative barbiturate therapy in severe head injury]

Efficacy and limitation of barbiturate therapy employed as postoperative treatment for acute traumatic intracranial hematomas were studied in 20 patients. The clinical cases in this series included 15 males and 5 females with mean age of 41.8 years who all were operated on for intracranial hematomas within 3 days after injury. Glasgow Coma Scale (GCS) score was less than 7 in all instances and intracranial pressure (ICP) as well as arterial pressure was monitored postoperatively with Gaeltec and Gould transducers. Barbiturate therapy (5 mg/kg of thiopental as an initial dose and loading dose of 2-3 mg/kg/hour) was given when ICP rose above 20 mmHg and maintained for 3 days after operation. The outcome of the patients was assessed by Glasgow Outcome Scale 3 months after injury. The response of barbiturate on ICP and the changes of cerebral perfusion pressure (CPP) during the therapy in relation to the outcome were studied. Final outcome of the patients revealed 5 of good (good recovery and moderate disability), 3 of poor (severe disability and vegetative state) outcomes and 60% of mortality rate. Eleven out of 20 patients responded to barbiturate therapy and 0-20 mmHg of ICP reduction (mean reduction of 10 mmHg) was obtained in these cases. Among these cases, 2 out of 3 dead patients were older than 60 years. There were no responses of barbiturate in 7 patients to whom the therapy was started when ICP rose above 40 mmHg. No response of the therapy on ICP was also observed in the patients with GCS score of 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study of four arginine ester hydrolases, ME-1, 2, 3 and 4 from the venom of Trimeresurus mucrosquamatus (the Chinese habu snake)

Four arginine ester hydrolases, ME-1, 2, 3 and 4 from the venom of Trimeresurus mucrosquamatus had been isolated and characterized by Sugihara et al. (1980, 1981, 1982, 1983). Immunologically, ME-1, 2, 3 and 4 are identical. The four enzymes hydrolyzed Pro-Phe-Arg-MCA and z-Phe-Arg-MCA. Furthermore, ME-2 slightly hydrolyzed Boc-Val-Pro-Arg-MCA, Boc-Phe-Ser-Arg-MCA and Boc-Ile-Glu-Gly-Arg-MCA. ME-1 cleaved almost simultaneously the Arg(22)-Gly(23) and Phe(25)-Tyr(26) bond of oxidized insulin B chain. ME-2 and 3 also hydrolyzed the same bond of insulin B chain, but the activity was not as potent as ME-1. ME-4 did not cleave the substrate. The four enzymes hydrolyzed C-terminal of arginine in the biologically active peptides. Four arginine ester hydrolases showed fibrinogenolytic activity. ME-1 and 2 first cleaved B beta-chain and then A alpha-chain. On the contrary, ME-3 and 4 cleaved A alpha- and B beta-chain simultaneously. The four enzymes also hydrolyzed fibrinogen in plasma cleaving B beta- and gamma-chain and slightly digesting A alpha-chain. The various inhibitors affected TAME (tosyl-arginine-methylester) and the fibrinogen hydrolytic activity of the four enzymes. All four enzymes had fibrinolytic activity.

Calcium antagonists and myocardial protection: a comparative study of the functional, metabolic and electrical consequences of verapamil and nifedipine as additives to the St. Thomas' cardioplegic solution

Using an isolated rat heart preparation as a model of cardiopulmonary bypass and ischemic arrest, a comparative study has been undertaken in order to characterize the functional, metabolic and electrophysiological consequences resulting from the addition of dl-verapamil or nifedipine to the St. Thomas' Hospital cardioplegic solution. Hearts (n = 6 in each group) were subjected to cardioplegic infusion with the St. Thomas' solution with or without added verapamil (1.1 micromoles/liter) or nifedipine (0.075 micromoles/liter). After 35 minutes of normothermic (37 degrees C) ischemic arrest, reperfusion was initiated and functional recovery was measured and expressed as a percent of its pre-ischemic control value. Inclusion of nifedipine in the cardioplegic solution improved the post-ischemic recovery of cardiac output from its control value of 59.8 +/- 3.0% to 80.0 +/- 2.5%. The temporal characteristics for the post-ischemic recovery of electrical activity and contractile performance were uncomplicated and similar to control hearts. Inclusion of verapamil also improved the protective properties of the St. Thomas' solution with cardiac output recovering to 76.8% +/- 2.8%. However, in contrast to the control and nifedipine groups, the profile for functional recovery was complex. After an early initial recovery, pressure development declined for 0.5 to 6.0 minutes. This occurred despite the recovery of electrical activity. Hearts then exhibited a second phase of recovery where pressure development returned to normal and this was sustained for the duration of the experiment. Analysis of electrocardiographic characteristics revealed a significant prolongation of the P-P and P-Q interval during the first 10 minutes of reperfusion in the verapamil group.(ABSTRACT TRUNCATED AT 250 WORDS)

[Significance of multimodality evoked potentials (MEPs) in severe head injuries]

Clinical significance of multimodality evoked potentials (MEPs) consisting of auditory evoked brainstem response (ABR), cortical somatosensory evoked potential (SEP) and visual evoked potential (VEP) was studied in 14 cases with severe head injuries. The cases in this series associated with cerebral contusion and/or intracranial mass lesions such as acute subdural, intracerebral and acute epidural hematomas and Glasgow Coma Scale (GCS) score was less than 8 in all instances. MEPs were recorded for 14 days after injury and evaluated by MEP grade modified from Greenberg, et al. Intracranial pressure (ICP) was monitored from the extradural space on main lesion side in all cases for 3 to 5 days. Transtentorial herniation on CT scan was also graded according to the status of subarachnoid cisterns around the tentorium. The outcome was assessed by Glasgow Outcome Scale at 3 months after injury and was classified into good, poor and dead. MEPs on admission showed mild to severe abnormalities determined by single or all modalities in all cases and they were fairly well correlated with GCS score on admission and initial ICP. In the cases with good outcome, initial MEPs showed mild to moderate abnormalities determined by single modality and improved within 3 days after injury. They returned to normal or remained at mild abnormality at 7 days. But abnormality on initial MEPs was more severe in the cases with poor outcome and they were deteriorated within 3 to 7 days when elevation of ICP above 25 mmHg was observed. MEPs remained at moderate abnormality even at 14 days after injury in these cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of left ventricular volume in assessing tetralogy of Fallot for total correction

Ninety-one patients with tetralogy of Fallot underwent intracardiac repair between 1978 and 1981. One patient died from left-sided heart failure. Retrospective analyses of this death revealed a significant decrease of the left ventricular (LV) end-diastolic volume index (EDVI) of 21 ml/m2 (36% of normal). Results of early postoperative hemodynamic studies after total correction of this anomaly suggested that an EDVI of 30 ml/m2 is the minimal requirement for adequate cardiac output postoperatively. Based on these data, 3 patients with decreased LV volume with EDVI of around 30 ml/m2 were challenged with the primary repair with success, although they required atrial pacing and catecholamine support postoperatively to maintain adequate left atrial pressure and cardiac output. From these results, it is recommended that patients with tetralogy of Fallot and an EDVI of 30 ml/m2 or more can be considered as candidates for the primary repair, but that patients with an EDVI of less than 30 ml/m2 should be palliated once by systemic-to-pulmonary arterial shunt procedures. Subsequent total correction should be performed after sufficient LV growth for those patients.

Comparative studies on (2'-5')oligoadenylate-related enzyme systems and the antiviral effect of interferon in two mouse cell lines which differ in (2'-5')oligoadenylate sensitivity of their protein synthesizing system

Effect of (2'-5')oligoadenylate (2-5A) on cellular and viral protein and RNA syntheses was investigated with two mouse cell lines, L929 and Lz (a subclone of L929). The oligonucleotide was introduced into the cells either by using calcium phosphate coprecipitation technique or by microinjection method. In L929 cells protein and viral RNA syntheses were severely inhibited by 2-5A, whereas in Lz cells, both were only slightly inhibited. The activities of 2-5A synthetase and double-stranded (ds)RNA-dependent protein kinase were enhanced by interferon (IFN) treatment roughly to the same extent and there was no significant difference in the level of 2'-5' phosphodiesterase activity either. On the other hand, 2-5A-dependent RNase (RNase L) activity in Lz cells was low, being about 10-20% of that of L929 cells. It was increased twofold after IFN treatment, but protein synthesis of Lz cells was not as sensitive to 2-5A as that of L929 cells even after IFN treatment. L929 and Lz cells were sensitive to the antiviral effect of mouse IFN against vesicular stomatitis virus (VSV) and Mengovirus. In contrast, however, Lz cells were relatively insensitive to the antiviral effect of IFN on vaccinia virus, whereas L929 cells were sensitive.

Activation of a human c-K-ras oncogene

The human lung carcinomas PR310 and PR371 contain activated c-K-ras oncogenes. The oncogene of PR371 was found to present a mutation at codon 12 of the first coding exon which substitutes cysteine for glycine in the encoded p21 protein. We report here that the transforming gene of PR310 tumor contains a mutation in the second coding exon. An A----T transversion at codon 61 results in the incorporation of histidine instead of glutamine in the c-K-ras gene product. By constructing c-K-ras/c-H-ras chimeric genes we show that this point mutation is sufficient to confer transforming potential to ras genes, and that a hybrid ras gene coding for a protein mutant at both codons 12 and 61 is also capable of transforming NIH3T3 cells. The relative transforming potency of p21 proteins encoded by ras genes mutant at codons 12, 61 or both has been analyzed. Our studies also show that the coding exons of ras genes, including the fourth, can be interchanged and the chimeric p21 ras proteins retain their oncogenic ability in normal rodent established cell lines.

Calcium antagonists and hypothermia: the temperature dependency of the negative inotropic and anti-ischemic properties of verapamil in the isolated rat heart

Using an isolated rat heart preparation under both aerobic and ischemic conditions we have characterized the temperature dependency of the slow calcium channel-blocking drug verapamil. In the first series of studies, isolated working rat hearts were subjected to global ischemia at 37 degrees, 34 degrees, 31 degrees, 29 degrees, 27 degrees, 25 degrees, and 20 degrees C. The duration of ischemic arrest was adjusted so that in the control group the postischemic recovery of function (aortic flow) was approximately 50% of its preischemic value. Ischemic times were therefore 35, 50, 55, 60, 80, 100, and 130 min, respectively. In all cases hearts were subjected to 3 min preischemic infusion with St. Thomas' cardioplegic solution with or without added verapamil (1.1 mumol/liter). At 37 degrees C verapamil increased recovery by 36.6 +/- 4.8%; this increased to 57.4 +/- 6.0% at 34 degrees C. Below 34 degrees C, however, additional protection was progressively lost, so that at 27 degrees C or below verapamil contributed no significant additional protection. In separate aerobic perfusion studies with paced Langendorff-prepared hearts with intraventricular balloons, verapamil (0.2 mumol/liter) was shown to depress pressure development by up to 76% at 37 degrees C; this increased to 92% at 34 degrees C, but thereafter the drug's negative inotropic effects declined, so that at 24 degrees C and below there was no significant difference in developed pressure between the control and drug-treated groups. On the basis of these and other studies, the argument is advanced that by some mechanism common to both hypothermia and verapamil, the anti-ischemic and negative inotropic effects of verapamil are rendered redundant under conditions of hypothermia.