A covalent fragment-based strategy targeting a novel cysteine to inhibit activity of mutant EGFR kinase

Several generations of ATP-competitive anti-cancer drugs that inhibit the activity of the intracellular kinase domain of the epidermal growth factor receptor (EGFR) have been developed over the past twenty years. The first-generation of drugs such as gefitinib bind reversibly and were followed by a second-generation such as dacomitinib that harbor an acrylamide moiety that forms a covalent bond with C797 in the ATP binding pocket. Resistance emerges through mutation of the T790 gatekeeper residue to methionine, which introduces steric hindrance to drug binding and increases the Km for ATP. A third generation of drugs, such as osimertinib were developed which were effective against T790M EGFR in which an acrylamide moiety forms a covalent bond with C797, although resistance has emerged by mutation to S797. A fragment-based screen to identify new starting points for an EGFR inhibitor serendipitously identified a fragment that reacted with C775, a previously unexploited residue in the ATP binding pocket for a covalent inhibitor to target. A number of acrylamide containing fragments were identified that selectively reacted with C775. One of these acrylamides was optimized to a highly selective inhibitor with sub-1 μM activity, that is active against T790M, C797S mutant EGFR independent of ATP concentration, providing a potential new strategy for pan-EGFR mutant inhibition.

Discovery of a Novel ATP-Competitive MEK Inhibitor DS03090629 that Overcomes Resistance Conferred by BRAF Overexpression in BRAF-Mutated Melanoma

Patients with melanoma with activating BRAF mutations (BRAF V600E/K) initially respond to combination therapy of BRAF and MEK inhibitors. However, their clinical efficacy is limited by acquired resistance, in some cases driven by amplification of the mutant BRAF gene and subsequent reactivation of the MAPK pathway. DS03090629 is a novel and orally available MEK inhibitor that inhibits MEK in an ATP-competitive manner. In both in vitro and in vivo settings, potent inhibition of MEK by DS03090629 or its combination with the BRAF inhibitor dabrafenib was demonstrated in a mutant BRAF-overexpressing melanoma cell line model that exhibited a higher MEK phosphorylation level than the parental cell line and then became resistant to dabrafenib and the MEK inhibitor trametinib. DS03090629 also exhibited superior efficacy against a melanoma cell line-expressing mutant MEK1 protein compared with dabrafenib and trametinib. Biophysical analysis revealed that DS03090629 retained its affinity for the MEK protein regardless of its phosphorylation status, whereas the affinity of trametinib declined when the MEK protein was phosphorylated. These results suggest that DS03090629 may be a novel therapeutic option for patients who acquire resistance to the current BRAF- and MEK-targeting therapies.

Direct catalytic asymmetric Mannich-type reaction of α-sulfanyl lactones

Catalytic asymmetric Mannich-type reactions of α-sulfanyl lactones to aldimines were promoted by a chiral Ag complex/DBU binary catalyst. The reaction proceeded in a syn-selective manner in high enantioselectivity. Alkylative activation of the sulfide of the Mannich adduct allowed for the formation of trisubstituted aziridines.

Effects of short- and long-acting calcium channel blockers on the relationship between blood pressure and physical activity

Calcium channel blockers are widely used as antihypertensive drugs. However, there is some controversy as to how they should be used. Our first aim was to clarify how the dihydropyridine calcium channel blocker, benidipine, affects the quantitative relationship between blood pressure (BP) and physical activity. The second aim was to determine whether there is a relationship between systolic blood pressure (SBP) and physical activity in patients with hypertension when treating with a short-acting (nifedipine) or long-acting (benidipine) calcium channel blocker. In Study 1, ambulatory BP and physical activity were measured simultaneously in 27 patients with hypertension before and after 6 months with benidipine. In Study 2, ambulatory BP and physical activity were measured simultaneously in 16 patients with hypertension before (placebo) and after 6 weeks of crossover treatment with nifedipine and benidipine. In Study 1, there was no difference in the SBP change caused by physical activity between the pre- and posttreatment periods. In Study 2, SBP was significantly related to physical activity in the placebo (16/16) and benidipine (16/16) groups but not in the nifedipine (12/16) group. The lowest BP during day-time and nighttime in the nifedipine group were significantly lower than those in the benidipine group. Plasma renin activity (ng/mL/h) was significantly higher in the nifedipine group (1.20+/-1.05) than in the placebo (0.57+/-0.59) and benidipine (0.75+/-0.78) groups. These findings indicate that nifedipine might interfere with the adaptation mechanism of BP changed by physical activity and that the activated renin-angiotensin system might cause cardiac events.

Two novel mutations in the adrenoleukodystrophy gene in two unrelated Japanese families and the long-term effect of bone marrow transplantation

We identified two novel missense mutations in exon 1 of adrenoleukodystrophy (ALD) gene in two unrelated Japanese families. The first, G(874)C transition results in Arg(163)Pro substitution in the cytoplasmic domain of the ALD protein in adrenomyeloneuropathy family. The second, C(679)G results in Ser(98)Trp substitution in the first transmembrane loop in childhood onset cerebral ALD family. Both mutations cause the substitution of polar amino acid (arginine and serine) with non-polar amino acid (proline and tryptophan). Bone marrow transplantation (BMT) from his non-affected his younger sister was performed on a boy with childhood onset cerebral ALD who showed neurological deficit and brain MRI abnormalities. We evaluated the effect of BMT over a 6-year period in terms of neurological deficit, the level of very-long-chain fatty acids (VLCFA) in plasma and fibroblasts, and brain MRI. After BMT, patient's peripheral white blood cells were replaced by donor's XX ones carrying a normal ALD gene confirmed by in situ hybridization using satellite DNA of the centromere of X and Y chromosomes as probes and the level of VLCFA in lymphocytes was within normal limit. However, his neurological state progressively deteriorated. BMT was not beneficial to him.

CALNUC (nucleobindin) is localized in the Golgi apparatus in insect cells

A mouse monoclonal antibody 12B1 was raised against Golgi fractions from Sf21 insect cells and selected as Golgi-specific by immunostaining of the cells. The antigen was purified from the cells by immunoaffinity chromatography with the monoclonal antibody, and its N-terminal and internal amino acid sequences were determined. Based on the partial amino acid sequences, cDNA encoding the antigen protein was cloned and sequenced. The amino acid sequence deduced from the cDNA nucleotide sequence showed a homology to those of CALNUC family proteins, CALNUC (or nucleobindin, a calcium-binding Golgi protein with DNA-binding activity) and protein NEFA (a cell surface protein with DNA-binding, EF-hand, and acidic domains). The insect protein had two EF-hand loops at the same sites as the mammalian CALNUC family proteins, but had no leucine zipper which the mammalian homologues commonly have. An electron microscopic immunoperoxidase study demonstrated that the insect protein was localized in the cis-Golgi cisternae and cis-Golgi networks. Since this localization is identical to that of mammalian CALNUC, the insect protein was considered to be a homologue of CALNUC rather than that of NEFA. Assays involving proteinase K digestion, sodium carbonate extraction and Triton X-114 extraction revealed that the insect CALNUC-like protein was a soluble protein tightly associated with the luminal surface of Golgi membranes as reported for mammalian CALNUC. The insect protein was also shown to have calcium-binding activity as does mammalian CALNUC. These data verify that the insect protein is CALNUC. The existence of CALNUC in insect cells suggests that CALNUC is an essential calcium-binding Golgi protein in a wide range of the animal kingdom. A phylogenetic tree analysis, however, suggested that NEFA was derived from CALNUC long after the segregation of a mammalian ancestor from an insect ancestor.

Combination therapy using prednisolone and cyclophosphamide slows the progression of moderately advanced IgA nephropathy

AIM

We retrospectively examined the effect of combination therapy using prednisolone (PSL) and cyclophosphamide (CPA) on the progression of IgA nephropathy (IgAN) in 45 patients with moderate to severe histological changes.

PATIENTS AND METHODS

Patients were recruited from 129 consecutive patients with IgAN seen over 10 years based on semiquantitative histological grading. They were divided into two groups: PSL+CPA group (n = 26, male/female = 11/15, age 40+/-3 years (SEM)) or control group undergone conventional therapy with or without antiplatelet agents (n = 19, male/female = 10/9, age 41+/-3). In PSL+CPA group, PSL and CPA treatment commenced using a dose of 30 and 50 mg/day, respectively. PSL was reduced by 5 mg every month.

RESULTS

The clinical parameters at the start of treatment such as age, gender, histological score, blood pressure, urinary protein excretion and serum creatinine concentration (SCr) were not different between the groups. The mean observation period in PSL+CPA group (3.3+/-0.3 years) was not different from the control group (4.0+/-0.7 years). In PSL+CPA group, urinary protein excretion, defined as the ratio of urinary protein to creatinine concentration (UP/UCr), significantly decreased from 3.9+/-0.4 to 1.3 +/-0.2 (p<0.01), whereas it remained high in the control group (3.8+/-0.7 to 2.7+/-0.8). The progression rate (PR), which was determined by the slope of the correlation between time after renal biopsy and reciprocal SCr, was significantly lower in PSL+CPA (0.054+/-0.014) than in the control group (0.172+/-0.032 dl/mg/year, p<0.001). Our results indicated that PSL+CPA combination therapy was effective in slowing the progression of moderately advanced IgAN.

CONCLUSION

We suggest that the immunosuppressive treatment with CPA is sometimes necessary to preserve renal function in patients with histologically advanced IgAN.

Sas3 is a histone acetyltransferase and requires a zinc finger motif

SAS3 was originally isolated as a gene related to SAS2, which encodes a positive regulator of transcriptional silencing in yeast. The Sas3 protein possesses an evolutionally conserved domain that is shared by a group of SAS-like factors. This conserved domain contains an atypical zinc finger motif and a putative acetyl-CoA binding motif. We showed that recombinant Sas3 exhibits histone acetyltransferase (HAT) activity toward acetylate core histones H2A, H3, and H4. This substrate specificity is similar to those of Tip60 and Esa1. Analysis of a series of deletion mutants revealed that the minimum region required for HAT activity is located within amino acid residues 241-577, including the domain conserved in the MYST family proteins. Amino acid substitution mutant analysis showed that both the acetyl-CoA binding motif and the zinc finger motif are required for HAT activity. These results suggest that SAS3 and its family members require the zinc finger motif for their activity.

Nonbacterial prostatitis caused by partial urethral obstruction in the rat

The pathogenesis of nonbacterial prostatitis (NBP) is not understood mainly due to the lack of appropriate experimental models. We developed a new experimental model of NBP by inducing a partial obstruction of the urethra (PUO) in the rat. Male Wistar rats aged 12 weeks were used. PUO was produced by a nylon ligature on the urethra over a rubber tube. The tube was slipped out after the ligature had been tied. Two rats were examined histologically 6 h, 1 day, 3 days and 7 days after PUO. In another group, two rats were killed at 1, 3 and 7 days after the release of the PUO that had been left in place for 3 days. On day 3, another eight rats with PUO and eight control rats had 2 ml of urine in the bladder replaced by the same volume of lucifer yellow (LY; 10 microg/ml, MW 500), microperoxidase (MP; 20 microg/ml, MW 1900), horseradish peroxidase (HRP; 10 microg/ml, MW 40 000), or saline as control, respectively. Lymphocytic infiltration and interstitial edema were noted in the prostate following PUO, being most prominent on day 3. After the release of the PUO, these inflammatory changes gradually disappeared. Only LY was noted within the prostatic stroma of the rats 2 h after bladder instillation. Intraprostatic urinary reflux may be an etiologic factor in NBP. The present study showed that lower urinary tract obstruction caused NBP in the rat. Penetration of prostatic tissue by low-molecular-weight substances in the urine may trigger NBP.

Neuroprotective effect of mild hypothermia cannot be explained in terms of a reduction of glutamate release during ischemia

An exogenous glutamate injection into the hypothermic hippocampal CA1 during 5-min ischemia produced the same extent of extracellular glutamate levels as observed in the normothermic CA1 during 5-min ischemia; however, neuronal death was not induced in the hypothermic CA1. Glutamate is released excessively into the extracellular space during ischemia, and is thought to induce brain injury by its neurotoxicity. It has been reported that the massive glutamate release is reduced by mild hypothermia, and it has been proposed that the reduction of ischemia-induced glutamate release exerts the neuroprotective effect on postischemic neuronal death. In the present study, to determine whether the neuroprotective effect of mild hypothermia on postischemic hippocampal CA1 neuronal death is due to the reduction of ischemia-induced glutamate release, gerbils were subjected to 5-min ischemia under hypothermic condition at 31 degrees C and were simultaneously injected exogenously with L-glutamate, so that the hypothermic CA1 around a microdialysis probe was exposed to the same extracellular glutamate levels as seen during normothermic ischemia, and the histological outcome was examined. An injection with 1 mM L-glutamate into the hypothermic CA1 during 5-min ischemia produced a similar extent of increased glutamate (17-fold increase) to that observed in the normothermic CA1 during 5-min ischemia (16-fold increase). However, neuronal death was not induced in the hypothermic CA1. This result indicates that the neuroprotective effect of mild hypothermia cannot be explained in terms of a reduction of glutamate release during ischemia.

Recovery of cardiac norepinephrine concentration and tyrosine hydroxylase activity by the central alpha2-adrenoceptor agonist guanabenz in rats with aortic constriction

Depletion of cardiac norepinephrine has been reported in cardiac hypertrophy. This depletion causes less support for cardiac output in response to sympathetic nerve activation. The central nervous system is thought to be involved in this abnormality. Correction of this abnormality is expected to restore proper support for the heart. Clipping of the ascending aorta or a sham operation was performed in 10-week-old rats. At 4 weeks after the operation, the left ventricular norepinephrine concentration in clipped rats decreased (p<0.01). The clipped rats and sham-operated rats were treated with either guanabenz (1 mg/kg) or a vehicle for 4 weeks starting from fifth postoperative week. The level of left ventricular norepinephrine increased more in clipped rats treated with guanabenz (469+/-37 ng/g) than in clipped rats treated with a vehicle (325+/-28 ng/g). The norepinephrine concentration in the left ventricle recovered significantly after the treatment with guanabenz (p<0.001). Tyrosine hydroxylase activity in the left ventricle also recovered after treatment with guanabenz (p<0.01). Modulation of sympathetic nerve tone by the alpha2-adrenoceptor agonist restored cardiac norepinephrine concentration and tyrosine hydroxylase activity. This could be a new approach to the treatment of heart failure.

Histological study of urinary bladder transplantation in rats

Patients who require cystectomy are usually treated with an ileal conduit or intestinal neobladder for urinary control. In some of them, however, the bowel segment cannot be used because of previous abdominal surgery or radiation treatment. Bladder transplantation from cadavers may be beneficial to these patients, if possible. To obtain basic knowledge about bladder transplantation, we developed an animal model of whole bladder transplantation in rats. Male Lewis rats weighing 270-320 g were used as both donors and recipients. Of the 23 recipients, 12 (52.2%) survived 7 days or longer after surgery. At 1 week after transplantation, the bladder showed loss of transitional epithelium and remarkable cellular infiltration. In the bladder at 5 weeks after transplantation, the transitional epithelium regenerated markedly and submucosal cellular infiltration was much improved. Regeneration of some smooth muscle cells was also noted. At 6 months after transplantation, the nerve fibers were recognized in the bladder and the volume of the transplanted bladder was well preserved (1.0-1.3 ml). This article describes an animal model of whole bladder transplantation in the rat which we produced and the results of our study. Because a large number of pure-bred animals can easily be used, we believe our rat model is very useful for basic studies of bladder transplantation.

Organization of the chicken histone genes in a major gene cluster and generation of an almost complete set of the core histone protein sequences

We present a detailed picture of the disposition of the histone genes in the chicken genome and an almost complete set of the core histone protein sequences. Thirty-nine histone genes, six H1, nine H2A, eight H2B, eight H3 and eight H4, were located within a histone gene cluster of 110 kb, which was covered by five cosmid clones and two lambda clones. Results of our sequence analyses, together with those reported previously, generated a set of the core histone amino acid sequences as follows: three H2A variants, four H2B variants, two H3 variants and an H4 protein.

Molecular structure of the transposable element ninja in Drosophila simulans

Genetically unstable DNA sequences of 16.1 kb in length were isolated from the white locus of the W(mky) strain of Drosophila simulans. This insertional DNA has some unique characteristics as a transposon. It is found in high numbers in this strain and its revertant strains W(psm1) and W(cho), but not elsewhere, and the sequence is a tandem triplication of a basic repeating unit. In order to determine the structure of the insert as whole and the functional unit as a transposon, we analyzed nine clones isolated from genomic libraries of W(psm1) and W(cho). The repeating unit of the 16.1 kb insertion was the retrotransposon ninja and the DNA sequence of the entire element was determined. The ninja transposon is 6644 bp in length, with a 316 bp long terminal repeat (LTR) on each end. It contains two openreading frames (ORFs), and the pol region is divided between the two ORFs in contrast the organization of other retrotransposons. An alignment analysis of the reverse transcriptase sequences suggested that the ninja element is the first Drosophila retrotransposon belonging to the Pao subgroup.

Initiation of unidirectional ColE2 DNA replication by a unique priming mechanism

The ColE2 DNA can be replicated in an in vitro system consisting of a crude extract of Escherichia coli cells. DNA synthesis requires a plasmid-coded protein (Rep) and host DNA polymerase I but not host RNA polymerase. Replication starts at a fixed region containing the origin and proceeds unidirectionally. The leading- and lagging-strand DNA fragments synthesized around the origin were identified from early replicative intermediates. The 5' end of the leading-strand DNA fragment was mapped at a unique position in the minimal origin and carried RNA of a few residues. The results suggested that the initiation of the leading-strand DNA synthesis does not require the host DnaG protein. Thus the Rep protein itself seems to be a primase. Synthesis of the primer RNA at a fixed site in the origin region on a double-stranded DNA template is a unique property of the ColE2 Rep protein among other known primases. The 3' end of the lagging-strand DNA fragment was mapped at a unique position just at the end of the minimal origin region. Termination of the lagging-strand DNA fragment at that position seems to be the mechanism of the unidirectional replication of ColE2 plasmid.

Primer RNA synthesis by plasmid-specified Rep protein for initiation of ColE2 DNA replication

Initiation of in vitro ColE2 DNA replication requires the plasmid-specified Rep protein and DNA polymerase I but not RNA polymerase and DnaG primase. The ColE2 Rep protein binds specifically to the origin where replication initiates. Leading-strand synthesis initiates at a unique site in the origin and lagging-strand DNA synthesis terminates at another unique site in the origin. Here we show that the primer RNA for leading-strand synthesis at the origin has a unique structure of 5'-ppApGpA. We reconstituted the initiation reaction of leading-strand DNA synthesis by using purified proteins, the ColE2 Rep protein, Escherichia coli DNA polymerase I and SSB, and we showed that the ColE2 Rep protein is a priming enzyme, primase, which is specific for the ColE2 origin. The ColE2 Rep protein is unique among other primases in that it recognizes the origin region and synthesizes the primer RNA at a fixed site in the origin region. Specific requirement for ADP as a substrate and its direct incorporation into the 5' end of the primer RNA are also unique properties of the ColE2 Rep protein.

[Clean intermittent catheterization in neurogenic bladder patients with vesicoureteral reflux]

BACKGROUND

For neurogenic bladder (NGB) patients with vesicoureteral reflux (VUR), renal deterioration constitutes a primary threat to survival. Although anti-reflux surgery for those patients was reported to be effective, the efficacy of clean intermittent catheterization (CIC) in such patients still remains to be clarified.

METHODS

Sixteen neurogenic bladder patients with VUR were treated with CIC. Eight of them had spina bifida and 3 had radical hysterectomy for uterine cancer. Other 5 patients had spinal cord injury, spondyrocace, measles encephalopathy, and 2 unknown diseases, respectively. Hyperactive bladder was noted in 11 patients, whereas hypoactive bladder was noted in 3. Three patients were not evaluated.

RESULTS

VUR was improved in only 3 patients (3 ureters), whose VUR grades were not more than III. Nine patients (13 ureters) had to have antireflux surgery. Although 3 of them needed bladder augmentation afterwards, the success rate of the antireflux surgery was 84.6%.

CONCLUSION

We concluded that CIC alone was not effective to control VUR in neurogenic bladder patients. Nevertheless, CIC remained a good treatment option when VUR was managed surgically.

Control of ColE2 plasmid replication: negative regulation of the expression of the plasmid-specified initiator protein, Rep, at a posttranscriptional step

The incA gene of ColE2 is involved in the copy number control and incompatibility. Two promoters were identified around the incA gene. Transcription of the mRNA for the essential plasmid-coded initiator protein (Rep) mainly starts at a site about 140 bp upstream of the initiation codon of the Rep protein. The second transcript (RNA I) of about 115 nucleotides with two stem-and-loop structures is entirely complementary to the 5' untranslated region of the Rep mRNA. By using translational and transcriptional fusions of the rep gene of ColE2 and the lacZ gene of Escherichia coli, the incA gene product was shown to regulate expression of the rep gene at a posttranscriptional step. The results also suggest that the target of the incA gene product is the 5' untranslated region of the Rep mRNA. Deletion analyses reported here show that a region(s) about 17 to 70 bp upstream of the initiation codon of the Rep protein and another region inside the coding frame are important for efficient production of the Rep protein. This suggests that some additional sequence elements other than the initiation codon and the Shine-Dalgarno region and/or a secondary structure of the Rep mRNA are required for efficient production of the Rep protein. These results show that RNA I is an antisense RNA for the Rep mRNA and imply that it might regulate expression of the rep gene at the initiation step of translation by sequestering such additional sequence elements and/or by disrupting RNA secondary structure. We propose that RNA I represents the incA gene product.

Control of ColE2 plasmid replication: regulation of Rep expression by a plasmid-coded antisense RNA

We isolated and characterized mutants of ColE2 with increased copy number (cop) and those with reduced sensitivity to the wild-type incA gene (inc). Both types of mutations were single-base substitutions in the incA region and simultaneously increased the plasmid copy number and reduced the inhibitory activity of the incA gene on ColE2 DNA replication. Most of the cop mutations also reduced sensitivity to the wild-type incA gene. These mutations were located in the region specifying the large stem-and-loop structures of RNA I and the 5' portion of the Rep mRNA. All these results indicate that RNA I interacts with the Rep mRNA and thereby inhibits expression of the Rep protein at a post-transcriptional step and that this is probably the only mechanism that controls the ColE2 Rep protein expression. It is suggested that only portions of the nucleotides in the loop region are involved in initial (kissing) interaction of these RNAs. The total level of rep gene expression in the host cells appears to be kept constant (at a level characteristic for each cop allele) irrespective of the actual plasmid copy number above a certain level, when rep gene expression is regulated by the incA gene on the same plasmid. These seem to be the basic mechanisms for the replication control of ColE2.

Exogenous histone H1 injection into mitotic cells disrupts synchronous progression of mitotic events by delaying chromosome decondensation

At the end of open mitosis, chromosome decondensation, nuclear envelope re-formation and reassembly of interphase microtubules following mitotic spindle dissociation occur coordinately. To determine whether these events progress only synchronously in vivo, we delayed chromosome decondensation by injecting of exogenous proteins into the mitotic rat kangaroo kidney epithelium (PtK2) cells. When histone H1 purified from calf thymus was injected at prometaphase, chromosome condensation was prolonged for several hours, and sister chromatid separation and cytokinesis did not occur. However, interphase microtubules reassembled and lamin B-positive structures re-formed around the condensed chromosomes. Exactly the same results were obtained on injection of bacterially expressed H1. Kinetic experiments showed that there were two types of lamin B-positive structures. One type (type A) was stained uniformly with anti-lamin B antibodies. The other (type B) showed peripheral lamin B staining; that is, the normal interphase staining pattern, and was found to be competent for nuclear protein transport. As the chromosomes decondensed, the amount of type A decreased and that of type B increased. However, even cells containing highly condensed chromosomes had both type A and type B. From these results, we conclude that the re-formation of microtubules and reassembly of a nuclear transport-competent envelope do not depend on chromosome decondensation.

Exogenous histone H1 injection into mitotic cells disrupts synchronous progression of mitotic events by delaying chromosome decondensation

At the end of open mitosis, chromosome decondensation, nuclear envelope re-formation and reassembly of interphase microtubules following mitotic spindle dissociation occur coordinately. To determine whether these events progress only synchronously in vivo, we delayed chromosome decondensation by injecting of exogenous proteins into the mitotic rat kangaroo kidney epithelium (PtK2) cells. When histone H1 purified from calf thymus was injected at prometaphase, chromosome condensation was prolonged for several hours, and sister chromatid separation and cytokinesis did not occur. However, interphase microtubules reassembled and lamin B-positive structures re-formed around the condensed chromosomes. Exactly the same results were obtained on injection of bacterially expressed H1. Kinetic experiments showed that there were two types of lamin B-positive structures. One type (type A) was stained uniformly with anti-lamin B antibodies. The other (type B) showed peripheral lamin B staining; that is, the normal interphase staining pattern, and was found to be competent for nuclear protein transport. As the chromosomes decondensed, the amount of type A decreased and that of type B increased. However, even cells containing highly condensed chromosomes had both type A and type B. From these results, we conclude that the re-formation of microtubules and reassembly of a nuclear transport-competent envelope do not depend on chromosome decondensation.

[Effect of enalapril on left ventricular hypertrophy and left ventricular function in patients with hypertension]

The aim of this study was to study the effect of enalapril (E) on left ventricular (LV) mass, LV function and blood renin-angiotensin (RA) in patients with hypertension. Sixteen hypertensives were included in this study (WHO I 8, WHO II 8, 49.5 +/- 10.5 yrs). They were examined for blood pressure and heart rate. Chest X-ray film, echocardiography (echo), X-ray computed tomography (CT) and RA before and after about 6 months of E administration were studied. The LV mass was calculated by CT. The LV function was measured by echo. RAS was unchanged during this study. LV mass was significantly reduced after E (121.4 +/- 25.6 vs 104.6 +/- 13.7 g/cm2). The LV systolic function was unchanged after E, but LV diastolic function improved. It was shown that the long-term administration of E improves LV hypertrophy and LV diastolic function without any change of RAS.

Presence of particular transcription regulatory elements in the 5'-intergenic region shared by the chicken H2A-III and H2B-V pair

The two chicken histone gene families, H2A and H2B, contain nine and eight members, respectively, within two major histone gene clusters. Six genes each from families H2A and H2B have been found to be closely associated in inverted directions as H2A/H2B gene pairs. Two previously sequenced H2A members (H2A-I and H2A-II) encode the same amino acid (aa) sequence (class I), whereas seven sequenced H2B genes encode three different variants (classes I, II and III). In this study, we first sequenced H2A-III, a member of the H2A family, which is located in inverted orientation and 350 bp upstream from H2B-V, encoding the class-III H2B protein. The protein encoded by H2A-III differs from the class-I H2A protein in a single aa (Ala70-->Pro; class II). As a step toward elucidation of the transcriptional regulation of the H2A and H2B families, we fused this 5'-intergenic region to the cat gene in inverted orientations to generate two chimeric plasmids, pH2A-III-350 and pH2B-V-350. Transient CAT assays using these constructs indicated that the promoter of H2B-V is more active than that of H2A-III. CAT assays with 5'-deletion mutants of H2A-III and H2B-V showed that they each possess particular transcriptional motifs which are located relatively close to, or apart from, their own coding regions. These findings, together with those reported previously on the H2A-V/H2B-II pair, suggest distinct manners of transcription regulation of different members of the chicken histone gene families, H2A and H2B.

The chicken histone gene family

1. Most of the chicken 43 core and H1 histone genes belong to two major histone gene clusters. 2. Each of six H1 genes encodes a different H1 protein sequence. 3. The known core histone genes, four H2A, seven H2B, and seven H3 genes, respectively, encode two, three and three different protein variants, whereas the four known H4 genes encode the same amino acid sequence. 4. The core histone genes have particular transcription regulatory elements within the 5'-flanking regions and the regulations of their expressions are distinct, even though they are members of the same core histone gene family. 5. There are some undefined differences in the DNA structures of the particular core histone genes in various chicken tissues and these structural variations probably result in differences in their transcriptional regulation.

Nucleotide sequence of the cDNA encoding mouse thyroid peroxidase

The nucleotide (nt) sequence of the cDNA encoding mouse thyroid peroxidase (TPO) has been determined. The TPO cDNA is 3281 nt long and its open reading frame encodes a protein composed of 914 amino acids (aa), including a putative initiation Met. The mouse TPO cDNA shows 75.3, 70.8, and 93.5% homology in the coding nt sequence with human, porcine, and rat TPO cDNAs, respectively. In the aa sequence, mouse TPO shows 73.4, 68.4, and 93.9% homology with human, porcine, and rat TPOs, respectively. Specifically, the aa sequence surrounding the proximal His residue, probably essential for TPO activity, is well conserved among these four organisms.

Nucleotide sequences of two members of the chicken H4 histone-encoding gene family

The nucleotide sequences of two genes (H4-III and H4-IV) from the chicken H4 histone-encoding gene family have been determined. The four H4 genes, including the previously sequenced H4-I and H4-II genes, encode the same amino acid sequence and possess several copies of the possible Sp1-binding sequences on the coding and noncoding strands within the 5'-flanking regions.

Cardiac acetylcholine concentration in the rat

Varying values for the acetylcholine (ACh) concentration in the rat heart have been reported. The possibility that the method of sampling may influence prompted a comparison of heart levels of ACh obtained by two different procedures for sacrificing animals. One method was by microwave irradiation in vivo and the others being in vitro on the irradiated heart removed after decapitation. There were significant differences found in cardiac ACh concentration between the in vivo irradiated group and the decapitation groups. In decapitated animals, the cardiac ACh concentration became increasingly lower on standing. We also measured the ACh concentration of right atrium, left atrium, right ventricle and left ventricle. They were 4.62 +/- 1.57 nmol/g (mean +/- SD), 2.58 +/- 1.01, 2.76 +/- 1.00 and 2.12 +/- 0.70, respectively. We conclude the microwave irradiation in vivo is a more appropriate method for determining the cardiac ACh concentration.

Specific role of an alpha,beta-unsaturated carbonyl group in gamma-glutamylcysteine synthetase induction by prostaglandin A2

The effects of prostaglandins (PGs) on cellular glutathione (GSH) status in L-1210 cells were examined. PGA2 and J2, which have an alpha,beta-unsaturated carbonyl group in the cyclopentane ring, elevated the GSH content, but PGB2, D2, E2 and F2 alpha did not show the effect. When L-1210 cells were incubated with various 2-cyclopentenone derivatives, 4-hydroxy-2-cyclopentenone and some of related compounds elevated cellular GSH levels. Subsequent study with cell-free extract of cultured L-1210 cells revealed that PGA2 and 4-hydroxy-2-cyclopentenone induced gamma-glutamycysteine synthetase activity at the transcriptional level. This induction was also found in other cultured mammalian cells such as HeLa S3, NIH/3T3 and porcine aorta endothelial cells. When L-1210 cells were incubated with PGA2 in the presence of 4-hydroxy-2-cyclopentenone and its analogues, they inhibited the accumulation of PGA2 in cell nuclei. Our findings thus suggest that an alpha,beta-unsaturated carbonyl moiety is responsible for enhancing the biosynthesis of gamma-glutamylcysteine synthetase in cultured cells.

[A case of cardiac myxoma associated with congenital oculocutaneous albinism]

This case is a 43 year-old-woman of left atrial myxoma associated with oculocutaneous albinism, who was admitted to our hospital because of nocturnal cough everyday. Electrocardiogram showed normal sinus rhythm and complete right bundle branch block. Chest X-ray disclosed slight enlargement of left atrium. Echocardiography revealed the left atrial pedunculated tumor, arising from atrial septum, prolapsing into left ventricle during diastole, which was coincided with lucent tumor by levophase of pulmonary arteriography. Feeder artery of this tumor was visualized by right coronary arteriography. Cardiac catheterization represented normal pressure of right-sided heart. Thus the diagnosis of left atrial myxoma was established. At the operation, radical excision of the base of tumor and septum and patch closure was undergone. The gross morphology and microscopic findings were consistent with myxoma.

Cardiac acetylcholine concentration in the mouse

We measured cardiac acetylcholine (ACh) in mice using four different methods. The mice in the in vivo irradiation group received microwave irradiation and then the hearts were removed. The animals in the in vitro irradiation group were decapitated and only the hearts were irradiated. The animals in the non-frozen group were decapitated and ACh was measured soon after the removal of the heart. The animals in the frozen group were decapitated and the hearts were frozen. There were significant differences in ACh concentrations between the in vivo irradiation group and the other groups. We also measured the ACh concentrations in both atria and ventricles after the mice were irradiated while alive. The atrial ACh concentration 1.70 +/- 0.70 nmol/g (mean +/- SD) was significantly higher than the ventricle concentration 1.07 +/- 0.30. We concluded the microwave irradiation of animals was suitable method of sacrifice for the measurement of cardiac ACh.

Direct blood pressure monitoring in patients with pheochromocytoma

In patients with pheochromocytoma, blood pressure was monitored continuously for 2 days using direct measurement techniques. Systolic blood pressure sometimes increased to more than 300 mmHg. These sudden elevations of blood pressure were associated with increased levels of plasma catecholamines. Pre-operative prazosin and propranolol therapy lowered mean systolic and diastolic blood pressure throughout the 2 day observation periods and was associated with decreased hematocrit levels. However, these agents did not prevent the rapid elevation of blood pressure.