Protein substrates and heat shock reduce the DNA-binding ability of Escherichia coli Lon protease

Interaction between the fusion protein MBP-Lon, formed by maltose-binding protein and Lon protease, and the plasmid pBR322 was studied to clarify the DNA-binding behavior of the Lon protease. Since the MBP-Lon fusion protein that was bound to the plasmid was strongly adsorbed by amylose resin, complex formation and dissociation were determined by quantifying the unadsorbed plasmid using agarose gel electrophoresis. The autolysis of MBP-Lon fusion protein was suppressed when the protein was bound to the plasmid. The plasmid was completely dissociated from MBP-Lon fusion protein by the addition of the protein substrates of Lon protease (i.e. alpha-casein and denatured bovine serum albumin). In addition, at high temperatures, MBP-Lon fusion protein lost its plasmid-binding ability, although it fully retained ATP-dependent protease activity. These results suggest that Lon protease loses DNA-binding ability when cells are exposed to abnormal conditions and the amount of damaged proteins increases. On the other hand, DNA probably plays an important role in controlling the Lon protease activity in cells under normal conditions by entrapping the enzyme.

Laparoscopic retrograde cholecystectomy (from fundus downward) facilitated by lifting the liver bed up to the diaphragm for inflammatory gallbladder

In order to safely and reliably perform laparoscopic cholecystectomy in severe inflammatory cases (e.g., acute or chronic cholecystitis), we have designed a method of suturing the liver bed to the diaphragm, lifting it cephalad so as to maintain a good operative field. Initially, we dissect the gallbladder fundus, fully dissecting the neck of the gallbladder from the liver and finally dissecting the cystic duct (laparoscopic retrograde cholecystectomy facilitated by lifting the liver bed up to the diaphragm; Lap-RC). This method is different from laparoscopic standard cholecystectomy (Lap-SC), in which dissection of the cystic duct is done first. One hundred and twenty-nine consecutive laparoscopic cholecystectomies for various gallbladder diseases were carried out at Nerima General Hospital between August 1991 and June 1994. Fifteen cases of Lap-RC and six cases of Lap-SC in a severe inflammatory group were comparatively evaluated. Thirteen cases of Lap-RC and 92 cases of Lap-SC in a noninflammatory group were also comparatively evaluated. The rates of conversion to laparotomy were 0% in Lap-RC cases (0/15) and 33% in Lap-SC cases (3/9) in the severe inflammatory group. The incidences of major postoperative complications were 0% in Lap-RC cases (0/15) and 17% in Lap-SC cases (1/6) in the severe inflammatory group. In conclusion, Lap-RC showed satisfactory results in terms of both safety and reliability in patients with severe inflammatory disease.

A case of Sheehan's syndrome associated with severe anemia and empty sella proved 48 years after postpartum hemorrhage

A 68-year-old woman was admitted to our hospital for severe normochromic and normocytic anemia. She had a history of prolonged postpartum hemorrhage at the age of 20 yr. Her menses were resumed thereafter and she gave birth to two other children, but her lactation was poor. She had no subjective symptom until the age of 63 yr when she complained of weakness and cold intolerance. Laboratory examination at admission revealed severe anemia (Hb 7.2 g/dl) with relatively low serum erythropoietin (EPO 20.4 mIU/ml) and panhypopituitarism. Empty sella was also found by magnetic resonance imaging (MRI). Hb levels were corrected by replacement with levothyroxine (75 micrograms/day) and hydrocortisone (10 mg/day), which was accompanied by an increase in serum EPO levels. These findings indicate that this is a very rare case of Sheehan's syndrome with severe anemia and empty sella proved at the longest reported interval of 48 yr after the provoking delivery, and that serum EPO levels are increased by replacement with glucocorticoid and thyroxine in panhypopituitarism.

Role of tumor necrosis factor-alpha and glucocorticoid on lipopolysaccharide (LPS)-induced apoptosis of thymocytes

Administration of bacterial lipopolysaccharide (LPS) into mice markedly induced the apoptosis of CD4+8+ thymocytes. The injection of anti-tumor necrosis factor (TNF)-alpha antibody or RU38486, a glucocorticoid receptor antagonist, into mice definitely inhibited LPS-induced apoptosis of thymocytes. Addition of the sera 1 h after injection of LPS into in vitro cultures of thymocytes caused thymocyte apoptosis. It was also prevented by either anti-TNF-alpha antibody or RU38486. Further, recombinant TNF-alpha and hydrocortisone collaborated in induction of the thymocyte apoptosis in vitro. The in vivo phenomenon of LPS-induced apoptosis of thymocytes was reproducible by the in vitro experimental system. It was therefore suggested that both TNF-alpha and glucocorticoid participate and collaborate as effector molecules in LPS-induced apoptosis of thymocytes.

[A case report of chronic sternal osteomyelitis after thoracic aortic aneurysmectomy]

A 76-year-old man, who was complicated with chronic sternal osteomyelitis after thoracic aortic aneurysmectomy was reported. He was treated with local wound care and antibiotics for about 3 months, but cutaneous fistula with persistent discharge required sternal bone debridement and omental pedicle grafting. After this treatment the patient was uneventful. 67Ga scintigram and 67Ga-SPECT may be more useful in the diagnosis of this serious complication.

[Treatment with bolus methylprednisolone for pure red cell aplasia after ABO incompatible bone marrow transplantation in a patient with chronic myelocytic leukemia]

Pure red cell aplasia (PRCA) was found in a male patient with chronic myelocytic leukemia after major ABO incompatible bone marrow transplantation (BMT). He had blood group O, and received BMT from an HLA identical sibling (blood group A). Erythrocyte-depleted marrow was transplanted. Methotrexate for short time and cyclosporine (CyA) were used for graft versus host disease (GVHD) prophylaxis. Engraftment of neutrophils and platelets were observed on day 14 and 22, respectively. The Ph1 chromosome disappeared on day 133. However engraftment of erythrocytes was not observed on day + 280. Bone marrow puncture revealed depletion of erythrocyte precursors. Anti-A isoagglutinin was persisted. There was no evidence of acute or chronic GVHD. Administration of prednisolone, discontinuance of CyA and subcutaneous infusion of recombinant human erythropoietin failed to improve PRCA. Bolus methylprednisolone (m-PSL) therapy started on day 284 resulted in rapid increase in reticulocyte counts within 6 days, which was followed by normal hemoglobin concentrations. We conclude that bolus m-PSL may be one treatment for PRCA after BMT.

Change in hepatic handling of hepatocyte growth factor during liver regeneration in rats

The change in the hepatic uptake clearance of hepatocyte growth factor (HGF) during liver regeneration in rats was examined. The hepatic uptake clearance per gram liver of 125I-labeled HGF in vivo decreased to a minimum level only 15 min after partial hepatectomy (PH). In the perfused liver, in which the effect of endogenous substances can be ignored, the hepatic uptake clearance of 125I-HGF did not change until at least 3 h after PH, suggesting that the decrease in the clearance in vivo is caused by some endogenous inhibitors. Such a decrease in the clearance cannot be explained only by the elevated endogenous HGF concentration in plasma. In addition, at 48 h after PH the decrease in hepatic uptake clearance was comparable for in vivo and perfused liver (approximately 50 and 60% reduction, respectively), suggesting that the decreased hepatic clearance in vivo at that time was caused mainly by reduction in the binding and/or uptake by the liver itself. In addition, the hepatic uptake clearance of 125I-HGF at that time in the presence of an excess (135 pM) of unlabeled HGF was comparable with that of the control, indicating that only the saturable portion of hepatic uptake clearance is reduced. The internalization rate constant representing the probability of cell surface-bound 125I-HGF being internalized per unit time increased to three times that of the control at 15 min after PH, demonstrating that the internalization of HGF is enhanced immediately after the start of liver regeneration.

Detection of substances with alcoholic or phenolic hydroxyl groups by generation of hydrogen peroxide with imidazole and peroxyoxalate chemiluminescence

On-line detection of substances with an alcoholic or phenolic hydroxyl group using imidazole and peroxyoxalate chemiluminescence was investigated qualitatively using a flow-injection method. The substances tested included six polyphenols, five monophenols and six sugars. After incubation at 80 degrees C with an imidazole buffer (pH 9.5) the substances were detected by peroxyoxalate chemiluminescence. The polyphenols tested (e.g., pyrogallol, purpurogallin, and dopamine) showed the strongest light emission. The sugars with hydroxyl groups (e.g., fructose and lactose) and the monophenols (e.g., phenol, serotonin, and beta-estradiol) produced only a weak light emission. Imidazole served two roles, it catalysed the reaction with the hydroxyl compound and initiated peroxyoxalate chemiluminescence on-line. A novel reactor formed by packing glass beads into a flow cell (Teflon) of a chemiluminometer improved the sensitivity of light detection.

Contribution of parenchymal and non-parenchymal liver cells to the clearance of hepatocyte growth factor from the circulation in rats

PURPOSE

The distribution of 125I-hepatocyte growth factor (HGF) to either liver parenchymal cells (PC) or non-parenchymal cells (NPC) was investigated in rats.

METHODS

After injection of a trace amount of 125I-HGF, the distribution of radioactivity determined by microautoradiography closely resembled that of 125I-epidermal growth factor which distributes mainly to PC.

RESULTS

The uptake clearance of 125I-HGF estimated by determining the radioactivity of isolated liver cells was three times higher for PC than for NPC. This suggests that HGF distributes mainly to PC at relatively low doses. On the other hand, the uptake clearance by PC fell on coadministering an excess (80 micrograms/kg) of unlabeled HGF, while no change was observed for NPC, indicating that a saturable process for the hepatic handling of HGF exists only in PC where the HGF receptor is expressed.

CONCLUSIONS

At such a dose the uptake clearance was comparable for both PC and NPC showing that HGF distributes to both cell types although NPC have few HGF receptors. Since the distribution to NPC was relatively non-specific and heparin-sensitive, it may be that heparin-like substances, which are believed to exist on PC and/or the extracellular matrix, also exist on NPC.

The future of voice-processing technology in the world of computers and communications

This talk, which was the keynote address of the NAS Colloquium on Human-Machine Communication by Voice, discusses the past, present, and future of human-machine communications, especially speech recognition and speech synthesis. Progress in these technologies is reviewed in the context of the general progress in computer and communications technologies.

Analysis of time-dependent change of Escherichia coli F1-ATPase activity and its relationship with apparent negative cooperativity

Except for the case of gradual activation of EF1 (F1-ATPase from Escherichia coli) caused by the dissociation of the epsilon subunit [Laget, P. P. and Smith, J. B. (1979) Arch. Biochem. Biophys. 197, 83-89], EF1 has long been thought not to show a time-dependent change in activity [Senior, A.E. et al. (1992) Arch. Biochem. Biophys. 297, 340-344]. Here, we report the time-dependent inactivation and activation of EF1, which are apparently similar to those of mitochondrial F1-ATPases [Vasilyeva, E.A. et al. (1982) Biochem. J. 202, 15-23]. Analysis of these changes as a function of ATP concentrations in relation to negative cooperativity revealed that the initial inactivation phase was attributable to the decrease in the Vmax associated with the low Km (around 10 microM), and the following activation, probably due to the dissociation of the epsilon subunit, corresponded to the increase in the Vmax associated with the high Km (in the order of 100 microM). Thus, the time-dependent change in EF1 activity is closely related to the apparent negative cooperativity (multiple Km values) of ATP hydrolysis.

Structure of two cecropin B-encoding genes and bacteria-inducible DNA-binding proteins which bind to the 5'-upstream regulatory region in the silkworm, Bombyx mori

Two genomic DNAs encoding cecropin B (CecB), an antibacterial protein from Bombyx mori, were cloned and sequenced. The number of CecB genes was estimated to be more than four copies per haploid by genomic Southern blotting. Two genes, CecB1 and CecB2, were located tandemly within 12 kb in the same orientation. These two genes encoded identical amino acids, though 15 nucleotides (nt) were different in the coding region and the intron size varied. About 90% of the nt spanning 800 bp in the 5'-untranslated region (UTR) were identical between the two genes. This 5'-flanking region contained characteristic sequences such as a repetitive element of B. mori (Bm1), an interleukin-6 response element (IL-6 RE), and two putative lipopolysaccharide (LPS) response elements (LPS RE). An electrophoretic mobility shift assay (EMSA) showed that the fat body contains at least three different nuclear proteins inducible by bacteria which bind to the 5'-UTR, suggesting that these proteins may be involved in CecB expression triggered by bacteria.

Oral low-dose etoposide therapy for refractory multiple myeloma with extramedullary involvement

A 65-year-old man was hospitalized with IgG kappa-type multiple myeloma (MM) and enormous subcutaneous plasmacytomas. Two different combination chemotherapy regimens (MMCP and AVPP) and alpha-interferon therapy were ineffectual. Oral administration of etoposide at 50 mg/day was subsequently started, the tumors completely disappeared after 5 months. The blood level of monoclonal protein became undetectable after 8 months of continuous treatment. The side effect noted was loss of hair. The course in this patient suggests that long-term daily low-dose administration of etoposide should be attempted in patients with refractory MM and extramedullary plasmacytoma.

K+ channel-opening properties of a novel compound, NIP-121, in guinea pig myocardium as compared with those of cromakalim

Myocardial effects of NIP-121, a novel compound with potent vasorelaxant activity, were examined in comparison with those of cromakalim in isolated tissue and cells from guinea pig hearts. NIP-121 and cromakalim concentration-dependently reduced the action potential duration (APD) of isolated papillary muscle; the effect was antagonized by glibenclamide. In isolated ventricular tissue, NIP-121 and cromakalim decreased the contractile force concentration dependently. In these two experiments, the potency of NIP-121 was approximately 20 times higher than that of cromakalim. The effects of NIP-121 and cromakalim on membrane currents were examined in voltage-clamped ventricular myocytes. NIP-121 (10(-6) M) and cromakalim (3 x 10(-5) M) increased the steady-state outward currents. The normal inwardly rectifying current-voltage relationship changed to a linear relationship that reversed at the K+ current reversal potential. The current activated by NIP-121 and cromakalim was inhibited either by glibenclamide or by increased intracellular ATP concentration. NIP-121, at this concentration, had little effect on the calcium current. Thus, NIP-121 was demonstrated to produce AP shortening and decrease in contractile force through activation of ATP-sensitive K+ currents in cardiac muscle, with a potency approximately 20 times higher than that of cromakalim.

Flat adenomas and flat adenocarcinomas of the colorectal mucosa in Japanese and Swedish patients. Comparative histologic study

PURPOSE

In recent years, flat adenomas of the colorectal mucosa have been intensively investigated by Japanese pathologists. Results of that work indicate that flat adenomas may antedate the development of colorectal carcinomas. Because of differences in the histologic definition of flat adenomas with severe dysplasia and with intramucosal carcinoma within the group, one single observer having both Western and Asian training in pathology reviewed the material.

METHODS

A total of 287 flat colorectal lesions were reviewed: 109 from the Karolinska Hospital, Stockholm, 137 from the Tokyo Medical and Dental University (TMDU) (which included 5 cases from the Nagoya City University), and 41 from the Cancer Institute (CI), Tokyo. Lesions were histologically classified following strict histologic criteria. Thus, flat adenomas were divided into those having low-grade dysplasia (LGD; having dysplastic cells in the deeper half of the epithelium), high-grade dysplasia (HGD; dysplastic cells were found even in the superficial half of the epithelium), intramucosal carcinoma (dysplastic glands displayed molding with buddings and often a cribriform pattern), and adenocarcinoma (braking through the muscularis mucosa, with neoplastic cells in the submucosal layer or deeper).

RESULTS

Whereas in Stockholm only 14.7 percent of lesions had HGD, as much as 56.9 percent and 56.1 percent, respectively, had HGD at the two Tokyo Hospitals. Intramucosal carcinomas were not found in the Stockholm material but occurred in 2.2 percent of lesions seen at TMDU and in 4.9 percent of those seen at the CI. Notably, only 2.7 percent of the specimens at Karolinska Hospital had invasive adenocarcinoma, but it was seen in as many as 4.4 percent at TMDU and 21.9 percent at the CI.

CONCLUSIONS

This study indicates that there were histologic differences between flat neoplasias of the colorectal mucosa harvested in Stockholm and Tokyo. In Japan lesions were obviously more advanced (in terms of HGD) and more aggressive (in terms of intramucosal and submucosal invasion). The cause for the differences found in those two disparate geographic regions remains poorly understood. The results, however, may help us understand some of the unclear points and discussions appearing in the literature on this subject.

Analysis of wild-type and e antigen-defective hepatitis B viruses during the course of a short-term corticosteroid therapy in chronic hepatitis B

Hepatitis B virus (HBV), with a G-to-a point mutation at nucleotide 83 in the precore region (mutant HBV83), accounts for most cases of hepatitis B e antigen (HBeAg)-defective HBV. However, it is still not clear how mutant HBV83 is associated with HBe seroconversion. Twenty-six HBeAg-positive patients with chronic hepatitis B who received oral prednisolone (30 mg/day) for 3 weeks were studied to clarify the prevalence of mutant HBV83 during the treatment using polymerase chain reaction with a restriction fragment length polymorphism assay. Twelve (46%) patients seroconverted to anti-HBe 1 year after treatment, whereas 14 (54%) did not. The proportion of mutant HBV83 to whole HBV remained unchanged in both groups during an acute exacerbation induced by withdrawal of corticosteroids. Among 12 anti-HBe-seroconverted patients, five (56%) of nine patients with only wild-type HBV at baseline developed detectable levels of mutant HBV83 while all three patients with a mixed viral population of wild-type HBV and mutant HBV83 at baseline developed a higher proportion of mutant HBV83 one year after treatment. In contrast, these changes were observed in only one (14%) of seven who failed to seroconvert. The results indicate that a flare-up of hepatitis precedes emergence or selection of mutant HBV83, followed by HBe seroconversion in patients with chronic hepatitis B.

Effects of high-calorie diet on blood pressure and sodium retention in spontaneously hypertensive rats and normotensive Wistar-Kyoto rats

Previous reports from our laboratory have documented that spontaneously hypertensive rats (SHR) have insulin resistance and that insulin resistance is enhanced by high-caloric diet (HCD) feeding. The aim of this study was to elucidate the effect of HCD on blood pressure and sodium retention in both SHR and normotensive Wistar-Kyoto rats (WKY). SHR and WKY were divided into two groups. One group of rats was fed normal diet (ND). The other rats were fed HCD. After the 8-week feeding period, insulin suppression tests were performed. The animals were individually housed in metabolic cages for the last 2 days of the experiment. Food consumption was recorded for 24 h, and a 24-h urine was collected to calculate the sodium excretory ratio. In both strains, body weight was significantly increased by HCD feeding. Blood pressure was significantly elevated in SHR by HCD feeding, whereas that of WKY was not affected by HCD feeding. In both strains, steady-state plasma glucose (SSPG) during the insulin suppression test was higher in the HCD group than in the ND group. SSPG was consistently higher in SHR than in WKY treated with HCD. Urinary sodium excretion ratio was significantly decreased in SHR by HCD, and plasma potassium concentrations were significantly lower in SHR with HCD than in SHR with ND, whereas those of WKY were not affected by HCD feeding. SHR are more sensitive to the induction of insulin resistance than WKY, resulting in sodium retention and elevation of blood pressure.