Covalent binding of a reactive metabolite derived from propranolol and its active metabolite 4-hydroxypropranolol to hepatic microsomal proteins of the rat

Repeated administration of propranolol (PL) to rats causes the inhibition of cytochrome P450-2D (P450-2D) enzyme. We recently found that 4-hydroxypropranolol (4-OH-PL) was biotransformed to 1,4-naphthoquinone (1,4-NQ) by superoxide (SO) anions in medium containing rat liver microsomes and NADPH and proposed that the binding of the quinone to P450-2D apoproteins might be one of mechanisms for the enzyme inhibition [Narimatsu et al. (1995) Chem. Res. Toxicol. 8, 721-728]. In this study, we have searched for possible sources of SO for the conversion of 4-OH-PL to 1,4-NQ in rat liver microsomes and determined the radioactivity covalently bound to microsomal proteins after incubation of radioactive PL and 4-OH-PL with rat liver microsomes. Elimination of 4-OH-PL from a mixture containing microsomes and NADPH was suppressed by carbon monoxide. Antibodies raised to P450-2B1 and -3A2 partially, and antibody against NADPH-cytochrome P450 reductase (fp2) markedly suppressed the reaction. 1,4-NQ was formed concomitantly with 4-OH-PL elimination by a reconstituted preparation of fp2. Binding studies using naphthalene ring (NR)- and side chain (SC)-radiolabeled PL and 4-OH-PL showed that radioactivity covalently bound to microsomal proteins was much higher from 4-OH-PL than from PL for the NR-labeled compounds, but higher from PL than from 4-OH-PL for the SC-labeled compounds. These results suggest that the 4-OH-PL formed from PL by P450-2D enzyme is converted to 1,4-NQ with loss of the side chain, and the 1,4-NQ accounts for most of the radioactivity covalently bound to microsomal proteins, including the P450-2D enzymes. The SO for conversion of 4-OH-PL to 1,4-NQ is supplied mainly by fp2 with some contribution by P450 enzymes.

Remnant-like very-low-density lipoprotein isolated from hypertriglyceridemic patients by immunoaffinity chromatography suppressed 3-hydroxy-3-methylglutaryl coenzyme A activity of cultured human skin fibroblasts

It has been previously reported that VLDL unbound to monoclonal antibody against apoB-100 was rich in apoE, thus resembling remnant particles (J Lipid Res, 1993:33;369-380). In the current study, we have further analyzed the unbound VLDL fraction in plasma from hypertriglyceridemic patients using a mixture of monoclonal antibodies against apoB-100 and apoA-1. The unbound VLDL isolated from the plasma of hypertriglyceridemic patients was found to be rich in apoE, apoB-48, and triglyceride compared with the bound VLDL. Furthermore, these unbound VLDL, but not bound VLDL, significantly suppressed HMG CoA reductase activity of cultured human skin fibroblasts (-20 to -25%, P = 0.0022). The degree of suppression is significantly correlated with the apoE content of unbound VLDL (r = -0.769, P < 0.05). Unbound VLDL failed to suppress the activity of HMG CoA reductase of LDL receptor negative fibroblasts. These observations indicate a potential atherogenicity of remnant-like unbound VLDL by delivering more cholesterol through the LDL receptor dependent pathway with apoE as a ligand. In conclusion, this new immunoaffinity chromatography system is a useful method for directly quantifying atherogenic remnants in plasma.

Loss of p53 is an early event in induction of brain tumors in mice by transplacental carcinogen exposure

Experimental carcinogenesis studies using p53-deficient mice have suggested that loss of function of this tumor suppressor gene is generally not an early event but is rather related to tumor progression. However, the biological functions of p53 and the accumulating evidence of alteration in human tumors imply a possible role for loss of p53 in the initial stages of tumorigenesis. Ethylnitrosourea administration to p53-heterozygous pregnant mice resulted in rapid development of primary brain tumors, which are extremely rare in mice, in 70% of the p53-null offspring. Brain tumors also developed later in 4% of heterozygous mice, but they had lost the wild-type allele. Thus, loss of normal p53 gene expression is of direct significance to early events in brain tumorigenesis, and this tumor suppressor gene may protect embryos from DNA damage in the brain induced by transplacental carcinogen exposure.

Mutations of the Ki-ras, p53 and APC genes in adenocarcinomas of the human small intestine

In contrast to the origins of colorectal carcinomas, the mechanisms of carcinogenesis in the small intestine remain unclear. We therefore analyzed the mutational status of the Ki-ras, p53, and adenomatous polyposis coli (APC) genes in primary carcinomas of the small intestine and compared the mutation patterns with those established for colorectal cancers. DNA was extracted from 15 formalin-fixed, paraffin-embedded lesions. Codons 12, 13 and 61 of the Ki-ras gene, exons 5-8 of the p53 gene, and codons 1268-1569, which contain the mutation cluster region (MCR) of the APC gene, were amplified by means of PCR, subcloned and sequenced. Mutations of the Ki-ras and p53 genes were observed in 8 (53.3%) and 4 lesions (26.7%), respectively. The mutational frequency of the Ki-ras gene in the present series of small intestinal carcinomas was similar, while that of the p53 gene was slightly lower than the reported frequencies for colorectal carcinomas. Only one case showed a mutation of the APC gene, involving an insertional mutation of an adenine at codons 1554-1556 with formation of a stop codon immediately downstream. Since the occurrence of an APC mutation is considered an early event in colorectal carcinogenesis, our findings indicating an extremely low frequency of such changes in and around the MCR suggest that carcinomas of the small intestine arise via a genetic pathway distinct from that involved in the development of carcinomas of the colorectum.

The effect of the selective PAF antagonist CIS-19 on PAF- and antigen-induced bronchoconstriction, microvascular leakage and bronchial hyperreactivity in guinea-pigs

We investigated the effects of a novel platelet-activating factor (PAF) receptor antagonist, CIS-19 [cis-2-(3, 4-dimethoxyphenyl)-6-isopropoxy-7-methoxy-1-(N-methyl-formamido)-1, 2, 3, 4-tetrahydronaphthalene], on PAF-, histamine-, substance P- and antigen-induced bronchoconstriction and microvascular leakage, as well as PAF- and antigen-induced bronchial hyperreactivity to methacholine in urethane-anesthetized guinea-pigs. Administration of CIS-19 (0.5-5 mg/kg, i.v.) inhibited the increase in lung resistance induced by PAF (30 ng/kg, i.v.) in a dose-dependent manner, but failed to inhibit the increase induced by histamine (30 micrograms/kg, i.v.) or substance P (6.5 micrograms/kg, i.v.). CIS-19 (5 mg/kg, i.v.) did not inhibit the increase in lung resistance induced by ovalbumin (2 mg/kg, i.v.) in actively sensitized guinea-pigs. PAF (30 ng/kg, i.v.)-induced microvascular leakage, measured by the extravasation of Evans blue dye, was dose-dependently inhibited by CIS-19 (0.5-5 mg/kg, i.v.) in the trachea, main bronchi and intrapulmonary airways, but it did not affect histamine (30 micrograms/kg, i.v.)- or substance P (6.5 micrograms/kg, i.v.)-induced microvascular leakage at all airway levels. CIS-19 (2.5 and 5 mg/kg) did not affect ovalbumin (2 mg/kg, i.v.)-induced microvascular leakage in all airway levels in actively sensitized guinea-pigs, CIS-19 (2.5 and 5 mg/kg, i.v.) significantly inhibited PAF-induced enhancement of the bronchial response to methacholine, but had no effect on ovalbumin (0.05 mg/kg, i.v.)-induced bronchial hyperreactivity in actively sensitized guinea-pigs. It is concluded that CIS-19 is a potent PAF receptor antagonist which inhibits PAF- but not antigen-induced bronchoconstriction, microvascular leakage and bronchial hyperreactivity. These results suggest that PAF plays little or no role in early airway responses following antigen challenge.

Purification and partial characterization of a novel human platelet aggregation factor in the extracellular products of Streptococcus mitis, strain Nm-65

A human blood platelet aggregation factor was purified from the extracellular products (ECP) of Streptococcus mitis, strain Nm-65 by sequential chromatography on DEAE-Sepharose CL-6B, hydroxyapatite and Superdex 75 columns. The purified factor (S. mitis-derived human platelet aggregation factor, Sm-hPAF) gave a single band with a molecular weight of 66 kDa on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Sm-hPAF showed a peak absorption at 278 nm and an isoelectric point of around 8.5. Chemical analyses revealed that Sm-hPAF contained no sugars and that its first 15 amino-terminal amino acid residues were H-DEQGNRPVETENIAR. Platelet aggregation activity of Sm-hPAF was abolished by heating at 45 degrees C for 10 min. Platelet aggregation by Sm-hPAF was accompanied by a release of prostaglandin E2 (PGE2) in a dose-dependent manner. The platelet aggregation was not inhibited by either prostaglandin E1 (PGE1) or Gly-Arg-Gly-Asp-Ser (GRGDS), that inhibit the platelet aggregation induced by collagen. Twenty (77%) platelet rich-plasma (PRP) specimens derived from 26 healthy volunteers were aggregated by Sm-hPAF, but the remaining 6 (23%) were not reactive. A preliminary study suggested the presence of an inhibitory factor against Sm-hPAF in the plasma from a non-reactive donor.

Essential research projects of oral health science in Tokyo Dental College for the 21st century

In this era of an aging society, no longer will it be sufficient for us to sit in small research units and concentrate on individual experiments. Tokyo Dental College must expand its abilities and develop new attitudes to meet society's evolving needs. The Search Eye 21 will provide us with new opportunities to identify such research goals and to unite coordinated efforts for the advancement of oral health science.

Abdominal actinomycosis: barium enema and computed tomography findings

A case of abdominal actinomycosis is described in a woman with recurrent right lower abdominal pain and low-grade fever without history of appendectomy. Past history included the use of an intrauterine device (IUD) until 10 years before manifestation of these symptoms. We followed up the patient, via diagnostic imaging, for 7 months. On initial barium enema, a polypoid lesion was visualized at the bottom of the cecum and there was constriction of the sigmoid colon; the appendix was not seen. Seven months later, poor extension at the cecum, severe constriction in the sigmoid colon, and narrowing of the terminal ileum were also visualized. On computed tomography (CT), the lesion was initially localized only in the ileocecal region adjacent to the sigmoid colon. After 7 months, the lesion had infiltrated adjacent anatomic components and showed direct infiltration of the pelvic space. Differential diagnosis was difficult, as it was not obvious whether this was a pelvic abscess due to inflammation or appendiceal carcinoma. Laparotomy was performed. Macroscopically, the lesion was not limited to the ileocecal region, but involved the right ureter, tubes the Fallopian and ovary, bladder, psoas muscle, and abdominal wall. Pathology findings showed, chronic inflammatory tissue with evidence of actinomycosis. Although previous reports have described a lack of specific findings in this disease. When actinomycosis is suspected, CT is recommended to define its extent.

Mothers' low care in the development of alexithymia: a preliminary study in Japanese college students

We examined the influences of perceived parental bonding on scores on alexithymia in a sample of 232 college students. Ratings on mothers' care, a scale of the Parental Bonding Inventory were significantly and negatively correlated with scores on the Toronto Alexithymia Scale, and also with ratings on Difficulty Describing Feelings but not Difficulty Identifying Feelings and Externally Oriented Thinking. These results were replicated in another sample of 156 college students. Although our findings were based on simple correlations, they suggest that perceived mothers' low care is related to adults' scores on alexithymia, in particular, the construct, Difficulty Describing Feelings.

Pathological consideration of a "blister-like" aneurysm at the superior wall of the internal carotid artery: case report

OBJECTIVE AND IMPORTANCE

Although the incidence is low, a very small aneurysm with a thin wall and no neck arises at the superior wall of the supraclinoid portion of the internal carotid artery and is called a "blister-like" aneurysm. However, the pathogenesis of such a vascular lesion remains uncertain.

CLINICAL PRESENTATION

A 57-year-old man developed a fatal subarachnoid hemorrhage caused by the rupture of a blister-like aneurysm at the superior wall of the internal carotid artery. An autopsy was performed, and the lesion was pathologically examined.

RESULTS

The internal elastic lamina and media had disappeared at the border between the eccentrically sclerotic and normal carotid wall. The gap in the internal elastica was covered with normal adventitia and fibrinous tissue. This portion was not composed of collagenous tissue as ordinarily seen in an aneurysmal wall. Neither infiltration of inflammatory cells nor dissection of the artery were observed.

CONCLUSION

The blister-like aneurysm appeared to be a laceration of the carotid wall based on degeneration of the internal elastic lamina.

Changes in the immunoreactivity of protein gene product (PGP) 9.5 in the cochlea of spontaneously diabetic WBN/Kob rats

The mechanism of hearing impairment due to diabetes mellitus was examined in relation to changes in the level of the immunoreaction for the protein gene product 9.5 in the cochlea of spontaneously diabetic WBN/Kob rats. At 7 months (33 weeks) of age, when half of the males of this strain manifest diabetes, male WBN/Kob rats were divided into two groups as follows: one group consisted of prediabetic animals showing slightly decreased tolerance to glucose with a normal plasma concentration of glucose, normal urinary excretion of glucose, and functional hearing impairment (assessed in terms of elevation of hearing threshold). The second group consisted of diabetic animals with glucose intolerance, high plasma glucose level, polyuria, urinary glucose excretion, and more apparent elevation of hearing threshold. According to morphometric analysis of the spiral ganglion, the number of ganglion cells was significantly smaller in both the prediabetic and the diabetic animals than in the age-matched control Wistar rats. The staining intensity for protein gene product 9.5 was increased in some spiral ganglion cells of diabetic animals, but decreased in others according to quantitative immunohistochemical analysis. On the other hand, the immunoreactivity for protein gene product 9.5 was similar in the prediabetic animals to that in the control Wistar rats. These results suggest that numerical and immunohistochemical changes in the spiral ganglion cells reflect the onset and degree of the diabetic hearing impairment.

[A successful removal of T4 lung cancer with its left atrial extension using cardiopulmonary bypass]

A 42-year-old man presented with cough, chest pain and dyspnea. The chest roentgenogram revealed a large mass shadow in the right upper and middle lobes with atelectasis and pleural effusion. Massive polypoid tumor extending into the left atrium was diagnosed by computed tomography and two dimensional echocardiography. In order to prevent sudden death and cardiac failure, surgery was performed. At first, the polypoid tumor in the left atrium was removed with a partial resection of the left atrial wall under cardiac arrest using cardiopulmonary bypass. Then, a right pneumonectomy was performed. Episodes of embolism were not observed during surgery. His postoperative course was almost favorable. The size of the tumor in the right lung was 18 x 15 x 8 cm and the one in the left atrium was 6.5 x 4.5 x 3 cm, respectively. Pathological examination of the resected specimen revealed the evidences of large cell carcinoma extending into the left atrium. Local recurrence with S9 metastasis of the left lung were detected 6 months after surgery, and he died 6 months later. It is emphasized that the extended surgery using cardiopulmonary bypass was useful for both prevention of embolism and improvement of quality of life.

Development of anterior cranial fossa dural arteriovenous malformation following head trauma. Case report

Dural arteriovenous malformations (AVMs) are considered to be acquired lesions that develop secondary to venous obstruction, which sometimes happens in head trauma. However, there has been a report of an anterior cranial fossa dural AVM that occurred independently of a history of head trauma, and there has been speculation that these malformations are congenital. The authors recount their experience with a patient who had an anterior cranial fossa dural AVM that was discovered incidentally. The lesion was fed by the bilateral anterior ethmoidal arteries and drained into the superior sagittal sinus via frontal cortical veins. The patient had a history of severe head trauma that had occurred 30 years earlier. This is the first case report in which a previous head trauma is strongly believed to be the cause of an anterior cranial fossa dural AVM. The authors postulate that anterior cranial fossa dural AVMs can develop secondary to a head trauma.

Serial analysis of hepatitis B virus core nucleotide sequence of patients with acute exacerbation during chronic infection

Recent studies suggest that hepatitis B virus (HBV) core region could be an immunological target and that amino acid (aa) substitutions are mostly restricted to a small segment located in the middle of the core region. We sequenced the middle portion of HBV core gene during the course of acute exacerbation of chronic hepatitis B, and compared aa variations between the region including ideal HLA-A2 binding motifs and the nonbinding region. Five HBeAg+ chronic hepatitis patients with subtype adr (three with HLA-A2 and two without HLA-A2) were selected and using polymerase chain reaction (PCR) and cloning system, the central part of core region (nt 2063 to 2365, 303 bp) was sequenced in sera from each patient at three time points; before, at the peak of, and after exacerbation of hepatitis. The second set of sera showed higher aa substitution rates in five and in three out of five patients compared with those of the first and third sera, respectively. No significant difference was found in the aa substitution rates for the region with ideal HLA-A2 binding motifs between patients with and without HLA-A2. In asymptomatic HBV carriers with persistently normal aminotransferase values, alterations of the aa sequence were not observed within the same time frame. The results suggest that aa substitutions often occur at some particular positions in the middle of HBV core region during acute exacerbation of the disease under possible host immune pressures. Furthermore, unidentified epitopes appear to exist in the central part of HBV core region and HLA-unrestricted lymphocytes may play a role in the immune response of chronic HBV carriers.

Endothelin-converting enzyme expression in the rat vascular injury model and human coronary atherosclerosis

BACKGROUND

Endothelin 1 has been implicated in various human diseases, including atherosclerosis. In this study, we examined the expression and localization of endothelin-converting enzyme-1 (ECE-1), the final key enzyme of endothelin 1 processing, in rat carotid arteries after balloon injury and in human coronary atherosclerotic lesions.

METHODS AND RESULTS

ECE-1 mRNA levels and ECE activity in rat balloon-injured arteries started to increase between 2 and 5 days after injury. The endothelin 1 content of tissue in injured arteries was concomitantly increased. Immunohistochemical staining located ECE-1 signals in endothelial cells in uninjured arteries, whereas ECE-1 immunoreactivity was detected in neointimal smooth muscle cells in injured arteries 5 to 14 days after balloon denudation. The size of the neointima was effectively reduced by phosphoramidon, an inhibitor of neutral metalloproteases, including ECE-1. In human coronary atherosclerotic lesions, intense ECE-1 immunoreactivity was detected in subsets of cells embedded in atheromatous plaque that correspond to smooth muscle cells and macrophages, as identified by staining for smooth muscle alpha-actin and CD68 surface marker, respectively.

CONCLUSIONS

The present study ascertained that ECE-1 is expressed in neointimal smooth muscle cells in rat balloon-injured arteries and in both smooth muscle cells and macrophages in human coronary atherosclerotic lesions. Blockade of ECE-1 was effective in reducing neointimal formation after balloon injury. Thus, ECE-1 may contribute to the process of injury-induced neointimal formation and atherosclerosis through the autocrine/paracrine effects of endothelin 1.

Unilateral meningoencephalitis with hemispheric slowing on EEG

We report a 12-year-old boy with unilateral meningoencephalitis due to non-herpes simplex virus. He experienced secondarily generalized partial seizures of the left extremities with loss of consciousness. In contrast with normal neuroimaging findings, interictal electroencephalograms (EEGs) showed prolonged slowing in the right hemisphere. This laterality agreed with the right brain dysfunction verified on neuropsychological examination. Follow-up EEG is important in such a subtle case with normal neuroimaging.

Differential binding of peptides substituted at putative C-terminal anchor residue to HLA-DQ8 and DQ9 differing only at beta 57

HLA-DQ8 (DQA1*0302-DQB1*0302: DQ beta 57 Ala) and (DQA1*0302-DQB1*0303: DQ beta 57 Asp) differ only at beta 57, at which polymorphism reportedly confers distinct susceptibility to insulin-dependent diabetes mellitus (IDDM). To identify the differential peptide binding affected by beta 57, we determined DQ9-binding peptides by affinity-based selection of a phage random peptide library using the biotinylated DQ9 complex. Nonconservative single-residue substitution of high-affinity DQ8- and DQ9-binding peptide (1KLPDYVLWSSSTVVGLGAAGA21) at the underlined residues significantly decreased the peptide binding to DQ8 and DQ9. Affinities of the wild-type 21-mer K4DYVLWSSSTV13 and K4AYAAWAAATA13 to DQ8 and DQ9 were practically the same. The K4DYVLWSSSTV13-based analogue peptides with substitutions at 12T showed that residues R, K, H, E, D, Q, N, T, S, V, L, I, F, M, W, and Y permitted binding to DQ8, whereas only R, T, V, L, I, F, M, W, and Y did so to DQ9. Thus, significant differences exist between DQ9 and DQ8, in that the majority of polar residues, regardless of their static charges at the residue 12, permitted binding to IDDM-susceptible DQ8, which is not the case for DQ9. The affinities of K4DYVLWSSSXV13 AND K4AYAAWAAAAX13 (where X is T, A, K, D, or I) were almost equal to DQ8 and DQ9, suggesting the DQ8- and DQ9-binding peptide motifs could accept both the 8-mer and 9-mer frames depending on intervening sequences between N- and C-terminal anchor residues. The biochemical basis of peptide-HLA interactions determined by DQ beta 57 is discussed.