Significance of mitral L wave to predict late recurrence of atrial fibrillation after radiofrequency catheter ablation

Background

Mitral L wave, prominent mid-diastolic filling wave in echocardiographic examinations, is associated with severe left ventricular diastolic dysfunction, and that has been reported to predict recurrent atrial fibrillation (AF) after cardioversion. However, association between mitral L wave and the outcome of AF after radiofrequency catheter ablation (RFCA) has not been established.

Objective

The aim of this study is to evaluate the predictive value of mitral L wave on AF recurrence after RFCA.

Methods

250 patients including 164 paroxysmal AF (65.6%) and 86 non-paroxysmal AF (34.4%) who received RFCA in single center from January 2015 to December 2016 were enrolled consecutively. Echocardiographic examinations before RFCA were recorded, and the mitral L wave was defined as a distinct mid-diastolic flow velocity with a peak velocity ≥20 cm/s following the E wave. Systematic follow-up was conducted after RFCA. Univariate and multivariate analyses were carried out to determine the factors predicting late recurrence of AF (LRAF) which means AF recurrence after 3 months. Enrolled patients were divided into groups with the L wave (L-group; n=57) or without the L wave (NL-group; n=193) based on the findings of echocardiographic examinations.

Results

During a follow-up of 35.0±17.6 months, the ratio of LRAF in the L-group was significantly higher than that in the NL-group (32 (56.1%) vs. 41 (21.2%), Hazard ratio [HR]: 3.55, 95% confidence interval [CI]: 2.33 - 5.42, p<0.001). Among the clinical factors, presence of mitral L wave, BNP value, non-paroxysmal AF and moderate-severe mitral regurgitation were related to LRAF. A multivariate analysis using a Cox proportional hazard model found that presence of mitral L wave (HR: 2.67, 95% CI: 1.30 - 5.48, p=0.007) was significantly associated with LRAF.

Conclusion

This study revealed that mitral L wave predicts late recurrence of AF after RFCA.

Funding Acknowledgement

Type of funding sources: None.

Substituent effects in aqueous solutions of carboxylate salts studied by x-ray absorption spectroscopy at the oxygen K-edge

The present study aims at probing the influence of different substituents of sodium carboxylate salts R-COO^-:Na⁺ in aqueous solutions, with R = H, CH₃, C₂H₅, CH₂Cl, CF₃, and C₆H₅. X-ray absorption spectroscopy was used in the oxygen K-edge region to highlight the effect of R on the energy position of the O1s-to-π_COO* resonance of the carboxylate ion. Ab initio static exchange and ΔSCF calculations are performed and confirm the experimental observations. We qualitatively discuss the results on the basis of the polar properties of these groups as well as on the basis of the π_COO* orbital energy in the ground states, the oxygen 1s orbital ionization energy, and the O1s-to-π_COO* resonance energy.

Electrocardiographic evaluation of depolarization and repolarization abnormalities in breast cancer patients with HER2-inhibitor related cardiac dysfunction

Background

The arrhythmic substrates of the myocardium such as depolarization and repolarization abnormalities are thought to reflect cardiac dysfunction prior to the morphologic left ventricular dysfunction. Activation time (AT), recovery time (RT) and T wave peek-end interval dispersion (Tpe-dispersion) are useful indicators of the arrhythmic substrate. We examined the appearance of depolarization and repolarization abnormalities in patients with cancer therapeutics-related cardiac dysfunction (CTRCD) using AT, RT and Tpe-dispersion.

Methods

We conducted a standardized case-control study of CTRCD with 40 patients who developed breast cancer and treated with trastuzumab (13 cases and 27 controls). We assessed the relation between electrocardiographic indexes, including AT, RT and corrected Tpe-dispersion, and CTRCD. QT intervals were measured by Fridericia method, and QT observer 3 software were used for the measurement of all electrocardiographic indexes.

Results

LVEF in case and control group were 45.7±8% and 69.2±6%, respectively. AT in aVR lead was significantly higher in case group compared with control (28.8±7ms vs 22.8±5ms, P=0.02). corrected Tpe-dispersion tended to be higher in case group than that of control group (43.2±19ms vs 31.9±10ms, P=0.06). QT dispersion and RT dispersion were not different between case and control group.

Conclusions

Our study demonstrated that AT in aVR may predict cardiac dysfunction in breast cancer patients with HER2-inhibitor related cardiac dysfunction. More detailed studies using other modalities which can detect depolarization and repolarization abnormalities, including ventricular late potentials and T wave alternans, are needed.

Funding Acknowledgement

Type of funding source: None

P93 The usefulness of dual cardiac autonomic nervous modulation assessment for prediction of mortality in patients with relatively preserved left ventricular ejection fraction

Background

Recent guidelines have stated that reduced left ventricular ejection fraction (LVEF) is the gold standard marker for identifying patients at risk for cardiac mortality. Although reduced LVEF identifies patients at an increased risk of cardiac arrest, sudden cardiac deaths (SCDs) occur considerably more often in patients with relatively preserved LVEF. Current guidelines on SCDs risk stratification do not adequately cover this general population pool. Heart rate variability (HRV) and heart rate turbulence (HRT) are non-invasive electrocardiography (ECG)-based techniques capable of providing relevant information on the cardiac autonomic nervous modulation. Although a large body of evidence about autonomic nervous modulation markers has been reported, the usefulness of HRV and HRT parameters for risk stratification in such patients with relatively preserved LVEF has not yet been elucidated.

Purpose

This study aimed to evaluate HRV and HRT parameters for predicting cardiac mortality in patients with structural heart disease (SHD), including ischemic heart disease, dilated cardiomyopathy and valvular heart disease, who have mid-range left ventricular dysfunction (LVD).

Methods

We prospectively enrolled 229 patients (187 men, age 63 ± 13 years) with SHD who have mid-range LVD (LVEF > 40%). HRV and HRT parameters based on 24-hour ambulatory ECG recordings (Fukuda Denshi Co., Ltd., Tokyo, Japan) were evaluated as follows; SDNN, triangular index, high and low frequency HRV, turbulence onset and slope. The primary endpoint was all-cause mortality. Univariate and multivariate Cox regression analysis were used to assess the association between these cardiac autonomic nervous modulation and mortality.

Results

During a mean follow-up of 21 ± 11 months, all-cause mortality was seen in 11 (4.8%) patients. Univariate Cox regression analysis showed that reduced SDNN (<50ms), reduced triangular index (<20ms) and HRT category 2 were significantly associated with the primary endpoint (P < 0.05). When HRT category 2 combined with reduced SDNN, Multivariate Cox regression analysis revealed that this combination more strongly associates with the primary endpoint (hazard ratio =7.91, 95%CI, 1.82-34.2; P = 0.006).

Conclusion

Dual cardiac autonomic nervous modulation assessment which combined HRT and HRV could be a superior technique to predict mortality in patients with relatively preserved LVEF.

P3754Comparison of the transdermal bisoprolol patch with the oral bisoprolol fumarate administration as a therapeutic agent for idiopathic frequent premature ventricular contractions

Background

The transdermal bisoprolol patch (TB) was designed to maintain a sustained concentration of bisoprolol in plasma by higher trough concentration than the oral bisoporolol fumarate administration (OB). It is unclear whether the TB is as effective in treating idiopathic premature ventricular contractions (PVCs) as the OB.

Purpose

We compared the efficacy between the TB and OB in treating idiopathic PVCs while considering their duration of action.

Methods

Among 198 patients with a PVC count of ≥3,000 beats/24 hours, 84 patients were divided into groups treated with TB 4mg (n=50) or OB 2.5mg (n=34). The PVCs were divided into positive heart rate (HR)-dependent PVCs (P-PVCs) and non-positive HR-dependent PVCs (NP-PVCs) based on the relationship between the hourly PVCs density and hourly mean HR. To evaluate the efficacy, PVC counts by 24-hour Holter electrocardiograms were measured at baseline and at 1 month after the initiation of the therapy.

Results

There were no significant between-group differences for the mean HR, PVC count, or type of PVCs. Both the TB (from 16,692±9,737 to 10,442±10,711 beats/24 hours, P<0.001) and OB (from 19,633±16,298 to 9,235±12,124 beats/24 hours, P<0.001) significantly decreased the total PVC count after the initiation of therapy, and a comparison between the two drugs showed no significant difference (P=0.46). In the P-PVC group, both the TB and OB significantly decreased the total PVC count (P<0.001, P=0.022 respectively), PVC count during the day-time (P<0.001, P=0.030 respectively), and PVC count during the night-time (P=0.0038, P=0.022 respectively). In contrast, in the NP-PVC group, neither the TB nor OB made any significantly change in the total PVC count (P=0.079, P=0.10 respectively), PVC count during the day-time (P=0.35, P=0.12 respectively), or PVC count during the night-time (P=0.11, P=0.12 respectively). The TB exhibited a significant reduction during each time period regarding the changes within 24-hours in the P-PVC count from baseline, while the OB did not significantly reduce the P-PVC count from baseline during each time period between 0 and 5 o'clock.

Conclusions

Compared with the OB, the TB could be used with the same efficacy for reducing the PVC count. The TB could be a more useful therapeutic agent for idiopathic P-PVCs during a 24-hour period than the OB.

P6559Long-term follow-up and outcomes of patients with discontinuation of oral anticoagulant therapy after successful ablation procedures for atrial fibrillation

Background

Oral anticoagulant therapy (OAT) is effective for preventing strokes in atrial fibrillation (AF) patients. Currently, there is controversy regarding the discontinuation of OATs in patients with ablation procedures to eliminate AF.

Aim

We investigated the incidence of major bleeding and ischemic strokes/systemic embolisms in low-risk patients that discontinued OATs after successful AF ablation procedures.

Methods

Of 330 consecutive patients that underwent AF ablation procedures and were prescribed one of the direct oral anticoagulants or warfarin, 207 AF patients (158 men, mean age 61±11 years) who discontinued OATs three months after the procedure were enrolled. The average CHADS2 and HAS-BLED scores were 1.0±0.9 and 1.2±1.0, respectively, which meant that most patients had a low risk for strokes.

Results

During follow-up, 31 patients (15%) had recurrences of AF. Those patients underwent a re-ablation procedure and then re-discontinued their OATs three months after the session. During a 60±13 months follow-up, major bleeding was observed in five patients (2.4%) and was associated with a higher HAS-BLED score (2.2±0.4 vs. 1.1±1.0, P=0.027). In contrast, none of the patients experienced ischemic strokes/systemic embolisms.

Conclusions

This prospective study demonstrated that in patients with successful ablation procedures and low risk scores for AF management, OATs could be discontinued three months after the procedure. Unnecessary continuation of OATs may increase the incidence of major bleeding during the follow-up.

Pseudo-subarachnoid hemorrhage found in patients with postresuscitation encephalopathy: characteristics of CT findings and clinical importance

BACKGROUND AND PURPOSE

High-attenuation areas (HDAs) called pseudo-subarachnoid hemorrhages (SAHs) may develop in some patients resuscitated from cardiopulmonary arrest (CPA), though no hemorrhage has occurred. We investigated the imaging characteristics and clinical significance of this phenomenon.

MATERIALS AND METHODS

CT images of consecutive patients resuscitated from nontraumatic CPA were reviewed and classified into cases with pseudo-SAH (pseudo-SAH[+] group, n = 9), those without pseudo-SAH (pseudo-SAH[-] group, n = 28), and those with true SAH (SAH-CPA group, n = 8). Typical patients with SAH (SAH group, n = 13) and 20 healthy individuals were also extracted as control groups. The degree of brain edema was scored visually as none, mild, or severe, and the CT values of the HDAs and brain parenchyma were measured. These parameters were compared among the groups. We also compared the prognosis between the pseudo-SAH(+) and pseudo-SAH(-) groups.

RESULTS

On CT, pseudo-SAH was associated with severe brain edema, whereas there was mild or no edema without pseudo-SAH. The CT values of the HDAs in the pseudo-SAH(+) group were significantly lower than those of the CPA-SAH and SAH groups (P < .0001). The brain parenchyma of the pseudo-SAH(+) group had the lowest CT values among all of the groups (P < .0001). The prognosis of the pseudo-SAH(+) group was significantly poorer than that of the pseudo-SAH(-) group in terms of both clinical outcome (P = .02) and survival (P = .046).

CONCLUSION

The findings of pseudo-SAH have several imaging characteristics differing from SAH and predict a poor prognosis. This provides important information that can be used for deciding treatment strategies.

Inhibitory effects of safe and novel SOD derivatives, galactosylated-SOD, on hepatic warm ischemia/reperfusion injury in pigs

BACKGROUND/AIMS

Oxygen-derived free radicals such as superoxide play an important role in ischemia/reperfusion (IR) injury during and after extensive liver surgery or liver transplantation. Superoxide dismutase (SOD) has protective effects against hepatic IR injury. The effect of native SOD is, however, limited because of rapid elimination from the blood circulation and poor affinity for liver cells. It was reported by our collaborators that a SOD derivative modified with galactose (Gal-SOD) was selectively delivered well to hepatocytes by direct attachment to galactose receptors. In the present study, the efficacy of this agent for attenuating hepatic warm IR injury was investigated using the pig model.

METHODOLOGY

After 45-min clamping of the hepatic artery and portal vein, pigs were divided into 3 groups according to the following treatments. Ten milliliters of normal saline in Group 1 (n=5), 10,000 units/kg of native SOD in Group 2 (n=5) and 10,000 units/kg of Gal-SOD in Group 3 (n=5) were given just prior to hepatic reperfusion. Liver function including clearance of total bile acid (TBA) and hyaluronic acid (HA) was investigated. Lipid peroxidase of the liver tissue (LPO) and histological findings were examined. In addition, survival rates of the pigs in each group were evaluated.

RESULTS

The survival rates at the 7th day after the operation were 60%, 80%, 100% in Groups 1, 2 and 3, respectively. Liver function tests, clearance of TBA and HA, and LPO levels were significantly improved in Groups 3 over findings in Groups 1 and 2. Congestion of hepatic tissues and vacuolization of hepatocytes in Group 3 were less than those in Groups 1 and 2. These results suggested that oxygen-derived free radicals were scavenged by Gal-SOD and IR injury was attenuated.

CONCLUSIONS

A safe and novel agent, Gal-SOD has a protective effect against hepatic warm IR injury.

Late-onset biliary leakage after laparoscopic cholecystectomy using laparoscopic coagulating shears. Report of a case

We recently encountered a rare case of late-onset biliary leakage after laparoscopic cholecystectomy using laparoscopic coagulating shears (LCS). The patient was a 49-year-old Japanese man who had undergone a laparoscopic cholecystectomy at Hamamatsu Medical Center after a diagnosis of cholecystolithiasis associated with localized adenomyomatosis. The cystic duct and the cystic artery were closed using LCS instead of metal endoclips. The postoperative course was uneventful, and the patient was discharged on the 4th operative day. However, on the 7th day after the surgery, the patient developed severe upper abdominal pain and was readmitted to our center with the diagnosis of a late biliary leakage, which was confirmed by an endoscopic retrograde cholangiogram. We then treated the leak successfully with endoscopic nasobiliary drainage.

Whole genome sequencing of meticillin-resistant Staphylococcus aureus

BACKGROUND

Staphylococcus aureus is one of the major causes of community-acquired and hospital-acquired infections. It produces numerous toxins including superantigens that cause unique disease entities such as toxic-shock syndrome and staphylococcal scarlet fever, and has acquired resistance to practically all antibiotics. Whole genome analysis is a necessary step towards future development of countermeasures against this organism.

METHODS

Whole genome sequences of two related S aureus strains (N315 and Mu50) were determined by shot-gun random sequencing. N315 is a meticillin-resistant S aureus (MRSA) strain isolated in 1982, and Mu50 is an MRSA strain with vancomycin resistance isolated in 1997. The open reading frames were identified by use of GAMBLER and GLIMMER programs, and annotation of each was done with a BLAST homology search, motif analysis, and protein localisation prediction.

FINDINGS

The Staphylococcus genome was composed of a complex mixture of genes, many of which seem to have been acquired by lateral gene transfer. Most of the antibiotic resistance genes were carried either by plasmids or by mobile genetic elements including a unique resistance island. Three classes of new pathogenicity islands were identified in the genome: a toxic-shock-syndrome toxin island family, exotoxin islands, and enterotoxin islands. In the latter two pathogenicity islands, clusters of exotoxin and enterotoxin genes were found closely linked with other gene clusters encoding putative pathogenic factors. The analysis also identified 70 candidates for new virulence factors.

INTERPRETATION

The remarkable ability of S aureus to acquire useful genes from various organisms was revealed through the observation of genome complexity and evidence of lateral gene transfer. Repeated duplication of genes encoding superantigens explains why S aureus is capable of infecting humans of diverse genetic backgrounds, eliciting severe immune reactions. Investigation of many newly identified gene products, including the 70 putative virulence factors, will greatly improve our understanding of the biology of staphylococci and the processes of infectious diseases caused by S aureus.

RseB binding to the periplasmic domain of RseA modulates the RseA:sigmaE interaction in the cytoplasm and the availability of sigmaE.RNA polymerase

The Escherichia coli sigmaE regulon has evolved to sense the presence of misfolded proteins in the bacterial envelope. Expression of periplasmic chaperones and folding catalysts is under the control of sigmaE RNA polymerase. The N-terminal domain of RseA sequesters sigmaE in the cytoplasmic membrane, preventing its association with core RNA polymerase. The C-terminal domain of RseA interacts with RseB, a periplasmic protein. The relative concentration of sigmaE:RseA:RseB is 2:5:1 and this ratio remains unaltered upon heat shock induction of the sigmaE regulon. Purification from crude cellular extracts yields cytoplasmic, soluble sigmaE RNA polymerase as well as membrane sequestered sigmaE.RseA and sigmaE.RseA.RseB. RseB binding to the C-terminal domain of RseA increases the affinity of RseA for sigmaE by 2- to 3-fold (Kd 50-100 nM). RseB binds also to the misfolded aggregates of MalE31, a variant of maltose binding protein that forms inclusion bodies in the periplasm. We discuss a model whereby the RseB-RiseA interaction represents a measure for misfolded polypeptides in the bacterial envelope, modulating the assembly of sigmaE RNA polymerase and the cellular heat shock response.

Selective importation of RNA into isolated mitochondria from Leishmania tarentolae

All mitochondrial tRNAs in kinetoplastid protozoa are encoded in the nucleus and imported from the cytosol. Incubation of two in vitro-transcribed tRNAs, tRNA(Ile)(UAU) and tRNA(Gln)(CUG), with isolated mitochondria from Leishmania tarentolae, in the absence of any added cytosolic fraction, resulted in a protease-sensitive, ATP-dependent importation, as measured by nuclease protection. Evidence that nuclease protection represents importation was obtained by the finding that Bacillus subtilis pre-tRNA(Asp) was protected from nuclease digestion and was also cleaved by an intramitochondrial RNase P-like activity to produce the mature tRNA. The presence of a membrane potential is not required for in vitro importation. A variety of small synthetic RNAs were also found to be efficiently imported in vitro. The data suggest that there is a structural requirement for importation of RNAs greater than approximately 17 nt, and that smaller RNAs are apparently nonspecifically imported. The signals for importation of folded RNAs have not been determined, but the specificity of the process was illustrated by the higher saturation level of importation of the mainly mitochondria-localized tRNA(Ile) as compared to the level of importation of the mainly cytosol-localized tRNA(Gln). Furthermore, exchanging the D-arm between the tRNA(Ile) and the tRNA(Gln) resulted in a reversal of the in vitro importation behavior and this could also be interpreted in terms of tertiary structure specificity.

Protective effect of nafamostat mesilate on injury of porcine hepatocytes by human plasma

Nafamostat mesilate (NM), a protease inhibitor, possesses a cytoprotective effect and inhibits the activation of complement. The present study investigated whether NM has any protective effect against injury of porcine hepatocytes by human plasma in a bioartificial liver support system. Porcine hepatocytes were harvested and seeded at a density of 2 x 10(5) cells on a 35-mm collagen-coated plate in Dulbecco's modified Eagle's medium (DMEM) with 10% fetal calf serum. Twenty-four hours later, the medium was replaced with human plasma with three concentrations of NM between 3.8 x 10(-5) and 3.8 x 10(-4) M and then cultured for 6 h. The viability of porcine hepatocytes, lactate dehydrogenase (LDH) levels, lidocaine clearance, porcine albumin production, and changes in complement (C3) levels were measured. The viability of porcine hepatocytes in human plasma decreased significantly to 37.7 +/- 11.4% of that in DMEM. NM improved the viability of the hepatocytes, lowered the levels of LDH, and increased lidocaine clearance and albumin production in a concentration-dependent manner. The concentrations of C3, the marker of xenogeneic reactions, did not change significantly, indicating that no hyperacute xenogeneic reaction occurred in our series. Together, our results suggested that NM exerts favorable effects on porcine hepatocytes in human plasma through direct effect such as prevention of protease activity in the plasma membrane of porcine hepatocytes rather than inhibition of complement-dependent immunoreactions.

A distinct segment of the sigma 32 polypeptide is involved in DnaK-mediated negative control of the heat shock response in Escherichia coli

Induction of heat shock proteins in Escherichia coli is caused by a transient increase in the cellular level of sigma 32 (the rpoH gene product), a protein required for transcription of heat shock genes. Both increased synthesis and stabilization of sigma 32 contribute to the increase in sigma 32. We previously showed that heat-induced translation of sigma 32-beta-galactosidase fusion protein encoded by an rpoH-lacZ gene fusion was mediated by an mRNA secondary structure formed between two 5'-proximal segments (A and B) of rpoH coding sequence spanning some 200 nt. We now report that a portion of the sigma 32 polypeptide that corresponds to further downstream (designated region C) is involved in the DnaK-mediated negative control resulting in the shutoff of heat-induced synthesis and degradation of fusion protein. Gene fusions carrying the 5' half (433 nt) or more of the rpoH coding sequence exhibited normal shutoff of synthesis, and the fusion proteins produced were very unstable, like authentic sigma 32; both the shutoff of synthesis and the instability of protein were markedly affected by the dnaK and dnaJ mutations. In contrast, gene fusions carrying < or = 364 nt (lacking region C) and a fusion carrying most of the rpoH sequence but with a frameshift mutation specifically affecting region C exhibited little or no shutoff and produced stable proteins. These results indicate that a distinct segment of sigma 32 plays a critical role in the negative feedback control of sigma 32. The control may be exerted during or after completion of sigma 32 synthesis mediated by interaction between nascent or mature sigma 32 and DnaK/DnaJ proteins.

Heat induction of sigma 32 synthesis mediated by mRNA secondary structure: a primary step of the heat shock response in Escherichia coli

Induction of heat shock proteins following transfer of E. coli cells from 30 degrees C to 42 degrees C depends on rapid accumulation of sigma 32, a minor sigma factor specifically required for transcription of heat shock genes. The synthesis of sigma 32 is induced by enhancing translation of its mRNA transcribed from the rpoH (htpR) gene. We previously showed that the translational control of rpoH-lacZ gene fusion is mediated by two cis-acting rpoH coding regions presumably involving mRNA secondary structure. To further examine this model, we constructed and analyzed a set of gene fusions carrying base substitution(s) or internal deletions within rpoH, including constitutive mutations predicted to destroy the mRNA secondary structure and compensatory second-site mutations that may restore the secondary structure. The results demonstrate that base pairings between the translation initiation region of some 20 nucleotides and part of the internal complementary sequences are critical for maintaining repression during steady-state growth and for modulating heat-induced synthesis of sigma 32-beta-galactosidase fusion protein upon temperature upshift. Furthermore, some of the compensatory mutations resulted in super-repressed (non-inducible) phenotypes, suggesting that the heat induction depends on a specific nucleotide sequence(s) as well as the mRNA secondary structure within the 5'-proximal regulatory segment of rpoH coding region.

Regulation of the heat shock response in E coli: involvement of positive and negative cis-acting elements in translation control of sigma 32 synthesis

When cells of E coli are transferred from 30 to 42 degrees C, the cellular level of sigma 32 (rpoH gene product) increases transiently, resulting in increased transcription of a set of heat shock genes. Both increased synthesis and increased stability of sigma 32 contribute to transient accumulation of sigma 32. Evidence suggests that synthesis of sigma 32 is enhanced primarily at the level of rpoH translation. We have constructed and examined the expression of deletion derivatives of rpoH-lacZ gene fusion at 30 degrees C and after shift to 42 degrees C. It was revealed that two cis-acting sequences within the rpoH coding region are involved in thermal regulation of fusion protein synthesis. One region immediately downstream of the initiation codon is required for high level expression, whereas the other internal region is involved in repression at low temperature. Thus, these regions act as positive and negative cis-elements in thermal regulation of rpoH translation. The rpoH mRNA secondary structure model suggesting an interplay between the two regions has been proposed to account for the temperature-induced sigma 32 synthesis as a primary cellular response to the heat shock stress.

Interplay of two cis-acting mRNA regions in translational control of sigma 32 synthesis during the heat shock response of Escherichia coli

When Escherichia coli cells are transferred from 30 degrees C to 42 degrees C, transcription from specific promoters recognized by RNA polymerase containing sigma 32 (the rpoH gene product) is transiently activated, resulting in induction of heat shock proteins. Transcription from heat shock promoters is activated by an increased cellular concentration of sigma 32 due to enhanced synthesis and stabilization. We have constructed and examined the expression of mutant derivatives (deletions and base substitutions) of rpoH-lacZ gene fusion. Synthesis of a sigma 32-beta-galactosidase fusion protein was found to be regulated at the translational level involving two distinct 5'-proximal rpoH coding regions. A small region immediately downstream of the initiation codon is required for potentially high-level expression, whereas a much larger internal region is required for thermal regulation--namely, repression at low temperature or nonstress conditions. The two mRNA regions act as positive and negative cis elements, respectively, in controlling rpoH translation. We propose that an interplay between these RNA regions involving secondary structure formation is important in regulating translation initiation and that transient disruption of secondary structure represents a primary step of the heat shock response.

The organization and evolution of transfer RNA genes in Mycoplasma capricolum

The genes for presumably all the tRNA species in Mycoplasma capricolum, a derivative of Gram-positive eubacteria, have been cloned and sequenced. There are 30 genes encoding 29 tRNA species. This number is the smallest in all the known genetic systems except for mitochondria. The sequences of 9 tRNA genes of them have been previously reported (1-3). Twenty-two genes are organized in 5 clusters consisting of nine, five, four and two genes (2 sets), respectively. The other eight genes exist as a single transcription unit. All the tRNAs are encoded each by a single gene, except for the occurrence of two tRNA(Lys)(TTT) genes. The arrangement of tRNA genes in the 9-gene cluster, the 5-gene cluster, the 4-gene cluster and one of the 2-gene clusters reveals extensive similarity with a part of the 21-tRNA gene cluster and/or the 16-tRNA gene cluster in Bacillus subtilis, respectively. The results suggest that the present M. capricolum tRNA genes have evolved from large tRNA gene clusters in the ancestral Gram-positive bacterial genome common to M. capricolum and B. subtilis, by discarding genes for redundant as well as non-obligate tRNAs, so that all the codons may be translated by as small a number of tRNAs as possible.

[Analysis of GM2 and anti-GM2 antibody in normal pregnancy]

Oncofetal antigen immunogenic (OFA-I), an antigen common to the fetal brain and some malignant tumors (derived from ectoderm), is immunogenic in man, and anti-OFA-I antibody appears in the sera of not only malignant patients but also pregnant women. Biochemical analysis revealed that OFA-I is ganglioside GM2 and GD2. In the present study, GM2 and anti-GM2 antibody were investigated as to the kinetics in pregnant sera and the tissue localization in placenta and decidua. The results obtained were as follows: 1. The concentration of GM2 was 76.7 pmol/ml (mean) in pregnant sera and 10.8 pmol/ml (mean) in cord sera. GM2 was not measurable in the sera of non-pregnant women. 2. GM2 was detected by thin layer chromatogram-immunostaining methods in the gangliosides extracted from decidua and term placenta. GM2 was, however, undetected from villi at an early stage. 3. In immunohistological analysis for GM2, positive findings were observed in decidua and in villous stroma of term placenta. In contrast, no distinct positive findings were observed in trophoblast at any stage. 4. Anti-GM2 antibody appeared in pregnant sera at an early stage and was detectable up to the 5th day postpartum.

[Studies of second-look operations (SLO) in ovarian cancer]

The Niigata Gynecological Cancer Society has been investigating the role of the second look operation (SLO) in the multi-disciplinary treatment of ovarian cancer, in cooperation with many other institutions, since 1981. One hundred seventy patients who underwent initial treatment for primary common epithelial ovarian cancer were analyzed in the present study. The distribution of clinical stages was as follows: stage I, 60 cases: stage II, 27 cases; stage III, 72 cases; and stage IV, 11 cases. Results; Five-year survival rates were 96% in stage I, 54% in stage II, 26% in stage III and 23% (4-year rate) in stage IV. Survival rates classified by the degree of completion of initial operation were 94% (5-year) in the complete extirpation group, 45% (4-year) in the group with residual tumor within 2 cm, 8% (4.5-year) in the group with residual tumor over 2 cm and 18% (5-year) in the exploratory laparotomy group. There were 89 cases of incomplete initial surgery, and 51 of them underwent SLO after FCAP therapy (Cisplatin + Adriamycin + Cyclophosphamide + 5-fluorouracil). Cancer was macroscopically completely removed in 20 cases (39.2%) by SLO, with the 4.5-year survival rate of 58%. In 25% of the cases with initial exploratory laparotomy group, the residual cancer was completely extirpated. There were 74 cases of complete initial surgery at stage I and stage II. They have been given FCAP therapy with 3 courses and maintenance chemotherapy. SLO was performed in 40 cases without clinical signs of recurrence. Recurrent cancer was noted in 2 cases (5%). On the other hand, 3 cases (12.5%) had recurred in 24 cases without SLO within about 2 years from initial operation. Consequently, SLO in the treatment of ovarian cancer is considered to be effective in the extirpation of residual cancer and in the early detection of cancer recurrence.

[Isolation of cisplatin-resistant subline from human ovarian cancer cell line and analysis of its cell-biological characteristics]

The cisplatin (CDDP)-resistant subline TYK-nu (R) was developed by culturing TYK-nu (human ovarian cancer cell line in vitro) with exposure to CDDP in stepwise increasing concentrations. The characteristics of both cell lines were compared and the results were as follows; 1. Both cell lines formed a monolayer in a pavement-like arrangement and large cells were occasionally present in TYK-nu (R) rather than TYK-nu. The population doubling time of TYK-nu and TYK-nu (R) was 43 hr and 48 hr, respectively. 2. IC50 (microgram/ml) in 96 hr treatment with CDDP and carboplatin (CBDCA) was 0.035 and 0.5 in TYK-nu and 0.62 and 2.0 in TYK-nu (R), respectively. 3. In the intracellular CDDP concentration, there was no marked difference between TYK-nu and TYK-nu (R) after CDDP (2.0 micrograms/ml) treatment in 2hr. 4. After treatment with CDDP (0.2 microgram/ml) or CBDCA (2.0 micrograms/ml), a decrease in S and G2 + M compartments was observed in the pattern of the DNA histogram of TYK-nu, but not in that of TYK-nu (R). 5. The majority of chromosomes in both cell lines were in hyperdiploid areas and the mode of TYK-nu and TYK-nu (R) was 56 and 51, respectively. The karyotype of TYK-nu (R) showed deletion of chromosome 7q. Thus, compared to TYK-nu, TYK-nu (R) was 17.7 times more resistant to CDDP and 4 times more resistant to CBDCA. The results suggest that the mechanism of resistance to CDDP may be due to genetic changes at the cellular level.

[Antitumor effect of UFT on human ovarian cancer grafted to nude mice and 5-FU concentration in tumor and normal tissues]

Antitumor effects of UFT, tegafur (FT-207), cisplatin (CDDP) and the combination of UFT with CDDP on a human ovarian cancer xenograft in nude mice and the concentration of 5-FU in the tumor tissue and major organs were studied. UFT (48.6mg/kg/day X 20) or tegafur (15.0mg/kg/day X 20) was daily administrated orally, and CDDP (5mg/kg/day X 3) was administrated intraperitoneally at an 7-day interval. The inhibition rates of the tumor growths were 49.6% with UFT, -2.3% with tegafur and 17.7% with CDDP, respectively. In the combination of UFT with CDDP, severe side effect were observed. The concentration of 5-FU in UFT-treated group was higher than tegafur group: about 2 times in the tumor, 5 times in the liver, 9 times in the kidney and 4 times in the spleen, respectively. In the combination of UFT with CDDP, the concentration of 5-FU in major organs, especially in the kidney, in nude mice that died at 10 day after drug administration were higher than in those of UFT. These findings indicate that UFT increases the intratumoral concentration of 5-FU to elicit better antitumor effect and also the concentration of 5-FU in various normal organs after long time administration.

[Clinical studies on the effect of imipenem/cilastatin sodium on infections in obstetrics and gynecology. Tissue concentrations and clinical effects]

Tissue transfer and clinical effects of imipenem/cilastatin sodium (MK-0787/MK-0791), a new carbapenem antibiotic, were studied and the following results were obtained. Penetrations of MK-0787 into uterine arterial blood and into pelvic dead space exudate were good. When MK-0787/MK-0791 was administered at a dose of 500 mg/500 mg by a 30-minute intravenous drip infusion, the peak level of MK-0787 in uterine arterial blood was 22.2 micrograms/ml, 30 minutes after the completion of the drip infusion. The peak level of MK-0787 in pelvic dead space exudate was 12.9 micrograms/ml at 2 hours and it dropped to 2.6 micrograms/ml at 6 hours. MK-0791 levels were similar to those of MK-0787. Penetrations of MK-0787 into tissues were also good. When MK-0787/MK-0791 was administered at a dose of 500 mg/500 mg by a 30-minute intravenous drip infusion, the level of MK-0787 was 2.2 +/- 1.1 micrograms/g in the oviduct, 2.7 +/- 2.1 micrograms/g in the ovary, 2.5 +/- 1.2 micrograms/g in the endometrium, 3.0 +/- 1.6 micrograms/g in the myometrium, 3.1 +/- 1.9 micrograms/g in the cervix uteri and 3.8 +/- 2.0 micrograms/g in the portio vaginalis at 1 hour after administration. These levels were reduced to halves, respectively, in approximately 2 hours. Four patients with intrauterine infections and 2 with vaginal stump infections were treated with MK-0787/MK-0791 at a daily dose of 1 g/1 g (500 mg/500 mg X 2). Good clinical and bacteriological responses were observed in 5 patients and causative organisms were eradicated in 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical effects of human fibroblast interferon in advanced gynecological cancers]

Human fibroblast interferon (IFN-beta) was given 13 cases of advanced gynecological cancers. Eight patients, who were clinically evaluable, were reported as follows; Patients consisted of ovarian adenocarcinoma (5), cervical adenocarcinoma (1), endometrial carcinoma (1) and tubal carcinoma (1). Route of administration was intravenous in 5 cases and intratumorous in 3 cases. IFN-beta dose ranged from 2, 650 X 10(4) to 10, 620 X 10(4) units. Clinical effects according to Koyama - Saitoh 's category was progressive disease (PD) in 7 cases and minor response (MR) only in one case who received intratumorous injection for recurrent tumor mass of tubal carcinoma in vaginal stump. Side effects of IFN-beta were chill and fever, fatigue and anorexia, leucocyte--and thrombocyte-- penia and hepatic dysfunction, though they were mild in grade and not dose-limiting factors. No anti-IFN-beta-antibodies were detected in any cases.

[Studies of anti-lymphocyte antibodies, with special reference to anti-B cell antibodies in choriocarcinoma]

For the purpose of elucidation of the immunologic properties of anti-lymphocyte antibodies which appeared in sera of choriocarcinoma patients, HLA typing of lymphocytes, complement-dependent lymphocytotoxicity test (CT) and mixed lymphocyte reaction (MLR)-blocking assay with patients' sera were performed in 7 couples with the disease. The results obtained were as follows: HLA distribution characteristic of patients and their husbands was not observed. In 3 of 7 patients, their sera exhibited positive CT to their husband's lymphocyte. In MLR-blocking assay, a significant blocking effects (BE) with sera were detected in all patients. The serum BE tended to be sustained for 4 to 8 months even after the decline of serum beta-hCG into the negative range. It was also observed that a case in whom the BE was positive for a longer period of time in a state of remission eventually underwent recurrence. It was demonstrated that the BE and MLR was induced by serum IgG antibodies closely associated with surface antigens of the husband's B-lymphocyte. Consequently, it was strongly suggested that serum anti-lymphocyte antibodies immunologically reflect the tumour burden in choriocarcinoma patients.

[Immunological analysis of hydatidiform mole and invasive mole (author's transl)]

Thirty-two cases of hydatidiform mole without endometrial invasion of chorial tissue and 17 of invasive mole were studied to ascertain whether these two diseases can be differentiated by various immune parameters. All of hydatidiform 11 of invasive mole were sampled at a state of "mole in utero" (pre-evacuation), but 6 of invasive mole were at a post-evacuation state, respectively. The results were summarized in the following items; 1. Serum total protein, especially albumin decreased with no significant difference in both groups. Globulin fractionation (alpha 1, alpha 2, beta, gamma-globulin) showed no characteristic changes. 2. A variation of immunoglobin (IgG, IgM, IgA) was similar in both. 3. Beta 1 C (a component of complement) increased in two groups, but no difference was revealed. 4. Leucocytosis was observed, but lymphocytosis was not detected in both groups. 5. Active E-RFC slightly increased, although total E-RFC and EAC-RFC were within normal range. But these findings were not statistically different in both. 6. In vitro lymphocyte-PHA-response was fairly depressed without a significant difference in two groups. 7. Suppressive effect of serum on lymphocyte-response was also slightly strengthened, but a difference in both was not significant. 8. The results of immune skin tests (PHA, PPD, SK-SD, Candida) could not be debated with liquid numbers studied.

[Studies on immunospecificity of skin test using tumor extract in gynecological malignancy (author's transl)]

Twenty-four patients of cervical cancer and 15 of ovarian cancer were studied to ascertain the presence of tumor-specific immune-response by in vivo and in vitro immunoassays. Soluble extracts of cell membranes as antigens were prepared from surgically obtained tumor tissues and normal tissues by 3M-Kcl method. Skin test and in vitro assays, such as Macrophage Migration Inhibition test, Leucocyte Adherence Inhibition assay and lymphocyte blastogenesis, were performed using these extracted antigens. 1. In skin test with autochthonous tumor extracts, positive reaction was revealed in 12.5% of cervical cancer cases and in 13.3% of ovarian cancer cases. There was no positive reaction in skin test with normal tissue extracts and allogeneic tumor extracts. 2. In in vitro assays, the percentage of positive was 30 to 40% in cervical cancer and 50 to 60% in ovarian cancer. It was observed that the patients with positive skin test tended to show also positive reaction in in vitro assays. 3. The positive percentage of non-specific skin tests (PHA, DNCB, PPD and SK-SD) was higher in the positive cases than in the negative in the tumor-specific skin test. Consequently, it was suggested that there were tumor-specific antigens in tumor tissues of cervical cancer or ovarian cancer and immune response of patients to these antigens might depend on individual-specificity.