Large right ventricular myxoma in a 79-year-old male

A 79-year-old male, admitted because of severe dyspnea on exertion, showed echocardiographic findings of a large tumor in the dilated right ventricle. The right ventricular outflow tract was nearly occluded by the tumor mass, and the mass was attached to the interventricular septum by a pedicle. The tumor removal operation was successful. The size of the tumor was 40 mm x 90 mm, and the weight 70 g. Microscopic findings showed typical myxomatous tissue with high cellularity, and no malignancy was observed. This is the oldest reported patient with right ventricular myxoma which was cured by operation.

Characterization of microtubule-associated protein 1-associated protein kinases from rat brain

The microtubule-associated protein (MAP) 1 preparation, MAP1A and 1B, obtained from rat brain microtubules was associated with protein kinases that were insensitive to cAMP, cGMP, calcium, calcium/calmodulin and calcium/phosphatidylserine. The fractionation of highly purified MAP1 by phosphocellulose chromatography revealed that protein kinase activity to phosphorylate phosvitin was separated into three major peaks (MAP1 kinases A, B and C). MAP1 was recovered in the MAP1 kinase A fraction and phosphorylated by the contained kinase. MAP1 kinase A is a novel protein kinase that is remarkably activated by poly-L-lysine and poly-L-arginine, but very insensitive to heparin among the kinases. Photoaffinity labeling using [alpha-32P]8-azido ATP indicated that the 65 kDa polypeptide is identified as an ATP-binding protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the highly purified MAP1 and MAP1 kinase A fractions. MAP1 kinases B and C may be identified as casein kinase I- and II-like kinases. The present results show that MAP1 is associated with at least three kinases and provide an insight for understanding thoroughly the MAP1-mediated microtubule functions.

Assessment of a Continuing Education Evaluation Framework

This study analyzes a systems model for evaluation research of continuing education (CE) and reports on the result of a quasi-experimental study of a stoma care CE program. Holzemer's conceptual framework for evaluating CE consisting of the learner, setting, and program along with a systems model was used as an organizing framework. A quasi-experimental design (n = 24 experimental group and n = 27 control group) was used to evaluate the impact of the CE program. Pre- and post-tests of participants' knowledge and skills of stoma care were evaluated. Participants' satisfaction with the course was surveyed by questionnaire during the course, on completion and four months after the course. No significant differences were found between the two groups. The revised framework included the concept of needs assessment and the impact of the CE program on patient care.

Effects of interferon-alpha, beta, and gamma on the function of differentiated leukemic HL-60 cells induced by 1,25-dihydroxyvitamin D3

The differentiation of HL-60, a human leukemic cell line, into monocyte-like cells (D3-HL-60 cells) is induced by 1,25-dihydroxyvitamin D3 (D3). We examined the effects of interferon (IFN) treatment of D3-HL-60 cells on the expression of cell surface antigens, the phagocytic activity for fluorescent beads, production of oxygen radicals, and intracellular growth of Legionella pneumophila. Activation of D3-HL-60 cells with IFN-gamma, Beta, and alpha for 24 h significantly increased expression of CD16, CD36, CD71, and HLA-DR antigens. IFN-gamma markedly enhanced the phagocytic activity of beads in D3-HL-60 cells. There was no significant difference in phagocytic activity between cells exposed to IFN-alpha or beta and untreated D3-HL-60 cells. IFN-alpha, beta, and gamma enhanced production of oxygen radicals, including superoxide, by D3-HL-60 cells. Superoxide production was enhanced to the greatest degree by IFN-gamma, followed by IFN-beta and then IFN-gamma. Intracellular growth of L. pneumophila in D3-HL-60 cells was inhibited by interferons (IFN-gamma > beta > gamma). Similar results were obtained in human mononuclear cells. These data indicate that interferons can act as biologic response modifiers not only in human mononuclear cells but also in differentiated leukemic cells. Our results may have implications for the development of differentiation therapy for treatment of leukemia.

Novel blockade of Ca2+ current by quinacrine in smooth muscle cells of the guinea pig

Effects of quinacrine on voltage-dependent Ca2+ channel current (ICa) were examined using whole cell voltage clamp in single smooth muscle cells isolated from vas deferens and urinary bladder and single cardiac myocytes from ventricle of the guinea pig. When ICa was elicited by depolarization from a holding potential of -60 to 0 mV for 150 msec every 15 sec in vas deferens myocytes, external application of quinacrine reduced the amplitude of ICa in a concentration-dependent manner in a range of 0.1 approximately 30 microM, and the IC50 of quinacrine was 1.3 microM. The block was at least partly removed by washout. The block of ICa by 1 microM quinacrine in vas deferens myocytes greatly depended upon the activation potentials but only slightly on the holding potentials. Use-dependent development of the block was also observed. Addition of 300 microM quinacrine to the pipette-filling solution did not significantly affect ICa. The IC50 of quinacrine for ICa block in urinary bladder myocytes was 1.1 microM and comparable to that in vas deferens. On the other hand, IC50 for the block of ICa elicited by depolarization from -45 to 0 mV in cardiac ventricular myocytes was 5.6 microM. It is concluded that quinacrine is a potent blocker of L-type Ca2+ channels in two types of smooth muscle myocytes and that the potency appeared to be approximately five times higher than that in cardiac myocytes. The action of quinacrine may be due to the direct block of Ca2+ channels from outside of the cell membrane.

Developmental changes in expression and distribution of the glutamate receptor channel delta 2 subunit according to the Purkinje cell maturation

The glutamate receptor (GluR) channel delta 2 subunit is considered to be a functional molecule involved in motor coordination, Purkinje cell synapse formation and cerebellar long-term depression. We examined developmental changes in expression and distribution of the GluR delta 2 in the mouse cerebellum by in situ hybridization and immunohistochemistry. The GluR delta 2 mRNA was detected as early as embryonic day 15 (E15) in a cell mass consisting of Purkinje neuroblasts in the posterior cerebellum. During late embryonic and postnatal periods, the GluR delta 2 mRNA was expressed abundantly and specifically in Purkinje cells. By immunohistochemistry, immunoreactivity of the GluR delta 2 was found in both shafts and spines of Purkinje dendrites at early postnatal period. By P21, however, the intense immunoreactivity became restricted to the dendritic spines, especially along the postsynaptic membrane in contact with parallel fiber terminals. These findings suggested that the transcription of the GluR delta 2 subunit occurs in the Purkinje cells from fetal through adult stage, but the intracellular localization of the protein products undergoes an alteration from non-synaptic to synaptic site when active synaptogenesis takes place.

Fluorimetric determination of nicorandil in human plasma by a high-performance liquid chromatographic-postcolumn ultraviolet irradiation [corrected] system equipped with on-line back-pressure tubing

For the determination of nicorandil in plasma, a fluorometric technique using HPLC-postcolumn UV radiation [corrected] has been developed. The chromatographic system consisted of a single pump, photoreactor and on-line back-pressure tubing. The system was suitable for the separation of nicorandil under the present reaction conditions. The calibration graph was linear over the range 6.5-1170 ng ml-1 using an injected volume of 100 microliters. The pretreatment of the plasma samples consisted only of deproteinizing steps by adding perchloric acid. The mean recovery from plasma was 90.2%.

Effects of water ingestion on gastric electrical activity and heart-rate variability in healthy human subjects

Electrogastrography (EGG) is a method to record electrical activity of the stomach using cutaneous electrodes. Power ratio (PR) is one of the parameters and means the relative change of EGG power of gastric activity from before to after certain stimulations (e.g., meals, water or drugs). Autonomic nervous function is an important modulator of gastric activity, but its relation with the EGG parameters has not been well clarified. We recorded EGG and the R-R interval simultaneously both before and after drinking 150 ml water for 400 s, and spectrally analyzed them using the maximum entropy method in 12 healthy volunteers. We calculated PR from before to after water ingestion, and the power of the high-frequency component of R-R interval variability before (pre-HF) and after water ingestion (post-HF), and their ratio (rHF = post-HF/pre-HF). PR was positively correlated with rHR (r = 0.727; P < 0.05) and negatively correlated with pre-HF (r = 0.706; P < 0.05), and rHF was negatively correlated with pre-HF (r = 0.776; P < 0.05). These results suggest that simultaneous recording of EGG and ECG for frequency domain analysis is necessary to estimate the vagal nervous activity.

Inhibition of metastasis in human gastric cancer cells transfected with tissue inhibitor of metalloproteinase 1 gene in nude mice

BACKGROUND

Tissue inhibitors of metalloproteinases (TIMPs) act as negative regulators of matrix metalloproteinases (MMPs) that degrade extracellular matrix. We evaluated the metastatic ability of the highly metastatic human gastric cell line KKLS, and that of cells transfected with exogenous TIMP-1 gene by the orthotopic transplantation model in nude mice.

METHODS

KKLS was derived from human gastric cancer. Expression of mRNA for tissue inhibitor of metalloproteinase-1 (TIMP-1) was almost undetectable in KKLS cells. KKLS cells were transfected with exogenous TIMP-1 gene by the Chen-Okay-ama method. Two clones (KTCLs) that expressed different levels of TIMP-1 and neomycin-resistant KKLS (K-neo) were obtained. The KKLS cells and these transfectants were orthotopically transplanted into nude mice (murine stomach) and metastasis in the murine liver was detected. As a method of detecting metastasis, we used a DNA fragment (human beta-globin gene) specific to human tumor cells that have metastasized into the murine liver by polymerase chain reaction (PCR).

RESULTS

Differences in tumor growth in the murine stomach were not observed between KKLS cells, K-neo cells, and the two transfectants expressing the different TIMP-1 levels (low, KTCL-1; high, KTCL-14). The KKLS cells and K-neo cells had undergone liver metastasis, as shown by PCR amplification of the human beta-globin gene fragment from the murine liver samples, since Week 1 after transplantation and the metastasis had grown exponentially; however, although KTCL-1 cells and KTCL-14 cells had undergone liver metastasis since Week 2, the metastasis had not grown. The average intensities of the amplified gene fragments from K-neo cells, KTCL-1 cells, and KTCL-14 cells in Week 4 after transplantation were 100%, 45%, and 18%, respectively, of the parenteral KKLS cells.

CONCLUSIONS

TIMP-1 was suggested to act as a negative regulator of the metastasis. The present data is thought to be especially important because the mice in this study underwent orthotopic transplantation with a metastatic model.

Production of a novel monoclonal antibody, JT-95, which can detect antigen of thyroid carcinoma

Monoclonal antibody (MAb) JT-95 was produced by immunization of mice with membrane fractions of a human thyroid carcinoma. Immuno-histochemical staining has demonstrated that the antigen recognized by JT-95 is strongly expressed in 95 (95%) of 100 cases of papillary carcinomas and in 3 (75%) of 4 cases of follicular carcinomas. In benign diseases of the thyroid gland, MAb JT-95 reacted with 0 (0%) of 39 adenomas, 1 (4%) of 21 adenomatous goiters, 0 (0%) of 8 hyperthyroidism specimens, and 3 (38%) of 8 chronic thyroiditis specimens. The antigen detected by MAb JT-95 has an apparent Mr 250,000 in thyroid carcinomas. Moreover, circulating antigen in thyroid carcinoma patients was detected by MAb JT-95 in an ELISA and in Western blotting. The circulating antigen has a Mr 105,000. MAb JT-95 conjugated with (131) I was administrated to nude mice bearing a human thyroid carcinoma. JT-95 131I accumulation at the transplanted tumor was visualized by autoradiography with 2.68-14.75-fold higher levels detected at the xenograft compared to that for normal organs. Based on these data, MAb JT-95 may be useful in the diagnosis detection and therapy of thyroid carcinoma.

Genetic alterations in rat colon tumors induced by heterocyclic amines

BACKGROUND

In rat colon tumors induced by the cooked food mutagens 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), ras and p53 alterations are rarely detected. To investigate the roles of the APC gene and microsatellite instability (MI) in PhIP-induced colon carcinogenesis, mutations of the APC gene and alterations of microsatellites were examined.

METHODS

Complimentary DNA sequence of the rat APC gene were determined by polymerase chain reaction (PCR) using primers based on the human APC sequence. PCR-single strand conformation polymorphism (SSCP) analysis was performed using primers based on sequences of flanking introns and exon 15. Microsatellite alterations were also analyzed using 85 microsatellite sequences dispersed through most of the rat chromosomes.

RESULTS

Five mutations in the APC gene were detected in four of eight PhIP-induced rat colon tumors. All five mutations involved deletion of a guanine base in a 5'-GGGA-3' sequence. Only 2 of 13 IQ-induced colon tumors had mutations of the APC gene and these were base substitution mutations. Seven of eight PhIP-induced colon tumors had microsatellite alterations in at least one locus, whereas no alterations were observed in the IQ-induced colon tumors.

CONCLUSIONS

The specific 5'-GGGA-3' to 5'-GGA-3' mutation and MI demonstrated in this study are strong evidence of a mutational fingerprint of PhIP.

Nitric oxide--a retrograde messenger for carbon monoxide signaling in ischemic heart

To examine the intracellular signaling mechanism of NO in ischemic myocardium, isolated working rat hearts were made ischemic for 30 min followed by 30 min of reperfusion. A separate group of hearts were pre-perfused with 3 mM L-arginine in the presence or absence of 650 microM of protoporphyrin, a heme oxygenase inhibitor for 10 min prior to ischemia. The release of NO was monitored using an on-line amperometric sensor placed into the right atrium. The aortic flow and developed pressure were examined to determine the effects of L-arginine on ischemic/reperfusion injury. Induction for the expression of heme oxygenase was studied by Northern hybridization. For signal transduction experiments, sarcolemmal membranes were radiolabeled by perfusing the isolated hearts with [3H] myoinositol and [14C] arachidonic acid. Biopsies were processed to determine the isotopic incorporation into various phosphoinositols as well as phosphatidic acid and diacylglycerol. cGMP was assayed by radioimmunoassay and SOD content was determined by enzymatic analysis. The release of NO was diminished following ischemia and reperfusion and was augmented by L-arginine. L-arginine reduced ischemic/reperfusion injury as evidenced by the enhanced myocardial functional recovery. Protoporphyrin modulated the effects of L-arginine. cGMP, which was remained unaffected by ischemia and reperfusion, was stimulated significantly after L-arginine treatment. The NO-mediated augmentation of cGMP was reduced by protoporphyrin suggesting that part of the effects may be mediated by CO generated through the heme oxygenase pathway. Reperfusion of ischemic myocardium resulted in significant accumulation of radiolabeled inositol phosphate, inositol bisphosphate, and inositol triphosphate. Isotopic incorporation of [3H] inositol into phosphatidylinositol, phosphatidylinositol-4-phosphate, and phosphatidylinositol-4,5-bisphosphate was increased significantly during reperfusion. Reperfusion of the ischemic heart prelabeled with [14C] arachidonic acid resulted in modest increases in [14C] diacylglycerol and [14C] phosphatidic acid. Pretreatment of the heart with L-arginine significantly reversed this enhanced phosphodiesteratic breakdown during ischemia and early reperfusion. However, at the end of the reperfusion the inhibitory effect of L-arginine on the phosphodiesterases seems to be reduced. In L-arginine treated hearts, SOD activity was progressively decreased with the duration of reperfusion time. The results suggests for the first time that NO plays a significant role in transmembrane signaling in the ischemic myocardium. This signaling appears to be on- and off- nature, and linked with SOD content of the tissue. The signaling is transmitted via cGMP and opposes the effects of phosphodiesterases by inhibiting the ischemia/reperfusion-induced phosphodiesteratic breakdown. Our results also suggest that NO activates heme oxygenase which further stimulates the production of cGMP presumably by CO signaling. Thus, NO not only potentiates cGMP mediated intracellular signaling, it also functions as a retrograde messenger for CO signaling in heart.

Levels of recombinant human granulocyte colony-stimulating factor in serum are inversely correlated with circulating neutrophil counts

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is effective in countering chemotherapy-induced neutropenia. However, serum rhG-CSF levels cannot be maintained throughout the course of rhG-CSF therapy. The drop in serum rhG-CSF levels may vary with the duration of rhG-CSF administration or with the circulating neutrophil counts. We investigated the relationship between serum G-CSF levels and circulating neutrophil counts and the pharmacokinetics of rhG-CSF for patients with lung cancer who had been treated with myelosuppressive chemotherapy and then with subcutaneous rhG-CSF (lenograstim, 2 micrograms per kg of body weight per day). Twelve patients were randomly assigned to four groups with different rhG-CSF therapy schedules. Serum G-CSF levels were measured by an enzyme immunoassay method. Serum G-CSF levels during the rhG-CSF therapy greatly exceeded endogenous G-CSF levels and were mainly due to the presence of exogenous rhG-CSF rather than increased levels of endogenous G-CSF. Despite the duration of rhG-CSF administration, serum G-CSF levels during rhG-CSF therapy were inversely correlated with circulating neutrophil counts (r2 = 0.73, P < 0.0001). The value for the area under the concentration-time curve of rhG-CSF on the day of neutrophilia was lower than that on the day of neutropenia (P < 0.05). Our results suggest that the fall in serum G-CSF levels during rhG-CSF therapy may result from increased clearance and/or decreased absorption of rhG-CSF, two processes related to circulating neutrophil counts.

APC gene mutations in human prostate cancer

Prostate cancer is the most common cancer in aged men. Although ras and p53 gene mutations have been detected in some prostate cancers, the major genetic alterations involved in its carcinogenesis are not well understood. Mutation of the APC gene is responsible for colorectal tumors in which ras and p53 mutations are also often involved. Using PCR-SSCP analysis and sequencing, we examined 31 human primary prostate cancers (three cases at stage A, 10 at stage B, five at stage C and 13 at stage D) and four cases of lymph node metastasis from the stage D cases, for mutations in the APC gene. A mutation was detected in only one of the 35 samples (3%). This mutation, present in a primary stage B cancer, had a T to C transition in exon 15 at the first position of codon 956, resulting in substitution of histidine for tyrosine. This study clarified that APC gene mutations are not largely involved in the development of clinical prostate cancer.

Functional requirement of gp130-mediated signaling for growth and survival of mouse primordial germ cells in vitro and derivation of embryonic germ (EG) cells

Leukemia inhibitory factor (LIF) is a cytokine known to influence proliferation and/or survival of mouse primordial germ cells (PGC) in culture. The receptor complex for LIF comprises LIF-binding subunit and non-binding signal transducer, gp130. The gp130 was originally identified as a signal-transducing subunit of interleukin (IL)-6 and later also found to be a functional component of receptor complexes for other LIF-related cytokines (oncostatin M [OSM], ciliary neurotrophic factor [CNTF] and IL-11). In this study, we have analyzed the functional role of gp130-mediated signaling in PGC growth in vitro. OSM was able to fully substitute for LIF; both cytokines promoted the proliferation of migratory PGC (mPGC) and enhanced the viability of postmigratory (colonizing) PGC (cPGC) when cultured on SI/SI4-m220 cells. Interestingly, IL-11 stimulated mPGC growth comparable to LIF and OSM, but did not affect cPGC survival. IL-6 and CNTF did not affect PGC. In addition, a combination of IL-6 and soluble IL-6 binding subunit (sIL-6R), which is known to activate intracellular signaling via gp130, fully reproduced the LIF action of PGC. Both in the presence and absence of LIF, addition of neutralizing antibody against gp130 in culture remarkably blocked cPGC survival. These results suggest a pivotal role of gp130 in PGC development, especially that it is indispensable for cPGC survival as comparable to the c-KIT-mediated action. We have further demonstrated that a combination of LIF with forskolin or retinoic acid, a potent mitogen for PGC, supported the proliferation of PGC, leading to propagation of the embryonic stem cell-like cells, termed embryonic germ (EG) cells. Since EG cells were also obtained by using OSM or the IL-6/sIL-6R complex in place of LIF, a significant contribution of gp130-mediated signaling in EG cell formation was further suggested.

[Dielectric behavior of rat lens and changes due to cold cataract]

To correlate the formation of cold cataract with changes in the passive electrical properties of the lens, we measured impedances of isolated rat lenses in the frequency range from 100 Hz to 500 MHz. Temperature-dependent, reversible changes were confirmed in the dielectric behavior as well as in the histological characteristics. The impedance of lenses showed two separate peaks (i.e. P1 and P2) when expressed in terms of loss tangent. At a low temperature of 4 degrees C, cytoplasmic "aggregates" characteristic of the cold cataract were formed inside the fiber cells of young rats with concomitant decreases in P2 (the peak value at higher frequencies), whereas no remarkable changes occurred in the control group. These results indicate that the lowering of P2 may reflect functional changes in the lens fiber membrane, an augmented heterogeneity in cytoplasm and/or decreases of protein-bound water. We conclude that the P2 is a useful dielectric index for the assessment of the nuclear opacity. This is the first report on the application of dielectric techniques to lenses with nuclear cataract. We suggest that dielectric spectroscopy may be applicable to a quantitative evaluation of cataract, not only of the cortical type but also of the nuclear type.

[A case of volatile solvent psychosis accompanied with multiple neurological and psychological symptoms]

A case of psychosis accompanied with variable symptoms induced by chronic volatile solvent inhalation is reported in this study. The patient was a 27-year-old male who had abused volatile solvents for 15 years, and was sent to the hospital because of a tonic-clonic seizure. Severe psychomotor excitement was observed on the first day and the 7th day after admission. After 10 days of admission, we observed visual transformation and hyperthermia, which suggested acute toxic symptoms due to a volatile solvent. Furthermore, symptoms such as incoherence, delusions of persecution, and catalepsy were also observed in this case. There have been few reports of multiple neurological and mental symptoms appearing in cases of volatile solvent psychosis. Although we sometimes experience cases of solvent abuse with acute mental symptoms and recurrent excitement after sedation, such symptoms are not always observed because of flashback in the strict sense. Therefore, careful early treatment should be employed to prevent 'secondary excitement'.

[Immunoglobulin heavy chain variable region(VH) genes in B cell clones producing anti-colon antibodies in ulcerative colitis]

We have established anti-colon antibodies producing B cell clones from the patient with ulcerative colitis, and analyzed the immunoglobulin heavy chain variable region (VH) gene segments of these clones using RT-PCR with VH family specific primers. VH3 family was used by all ten clones from ulcerative colitis that produced anti-colon antibodies, while various VH gene families were used by eight clones from normal controls. By nucleotide sequence analysis, two LPL clones were thought to be derived from a germ line gene segment, VH26. However, other three PBL clones were derived from 22-2B, 9-1 and 1.9-III, respectively. These results suggest the heterogeneity of the colonic antigens that autoantibodies in ulcerative colitis recognize.

Serial growth of human malignant fibrous histiocytoma xenografts in immunodeficient mice

Malignant fibrous histiocytoma (MFH) is on of the most common soft tissue sarcomas of adulthood, the only treatment for which involves surgical resection of the extremities and retroperitoneum, while no standard postoperative adjuvant chemotherapy has been established. We report herein on the establishment of a serially transplantable MFH strain in immunodeficient mice. An intraperitoneal tumor was resected from a patient with multiple recurrent MFH, inoculated into the subcutaneous tissue of mice with severe combined immunodeficiency (SCID), and established as a serially transplantable MFH strain, MH-1. The chemosensitivity of MH-1 was similar to that of the original fresh surgical specimen, as confirmed by the 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) test. We believe that this serially transplantable strain will be useful for further studies on chemotherapy effective against MFH.

Binding of benanomicin A to fungal cells in reference to its fungicidal action

An antifungal antibiotic, benanomicin A, binds in the presence of Ca2+ to susceptible fungi and some bacteria, but not to antibiotic-resistant bacteria and mammalian cells. With the susceptible yeast Saccharomyces cerevisiae, benanomicin A binds similarly to whole cells and to protoplasts. Studies using benanomicin A and three structurally related derivatives suggested that a carboxylic acid in the D-alanine moiety and a sugar moiety in the benanomicin A molecule are essential for both binding and antifungal activities against growing S. cerevisiae. An amino substituent on the sugar moiety can be replaced with a hydroxyl group without the loss of activities. Benanomicin A binds to various yeast mannans which differ in glycosidic linkages. These results indicate that binding of benanomicin A to the mannan portion of fungal cells is essential for exertion of the antifungal activity.

Relationship between N-acetyltransferase (NAT) activity and liver protoporphyrin level in experimental porphyria

The results of our previous studies demonstrated that isonicotinic acid hydrazide (INH) can aggravate griseofulvin (GF)-induced protoporphyria in mice. To elucidate this phenomenon, we studied the relationship between liver protoporphyrin (PP) levels and N-acetyltransferase (NAT) activity, which is known to be a major catabolic enzyme of INH metabolism in the liver. The results revealed a significant correlation between liver PP levels and NAT activity in the mice fed 0.1% GF and 0.05% INH. In this group, mice with high NAT activity developed severe protoporphyria. There was no correlation, however, between liver PP levels and NAT activity in the mice fed GF alone or INH alone. The result suggested that INH metabolites formed by NAT enhance the hepatotoxicity of GF in mice.

Novel biochemical diagnostic method for aortic dissection. Results of a prospective study using an immunoassay of smooth muscle myosin heavy chain

BACKGROUND

Aortic dissection is one of the most common aortic catastrophes. Although newer diagnostic methods as exemplified by image diagnostic techniques have greatly improved the diagnosis of aortic dissection, the diagnosis is still frequently missed today because the signs and symptoms of the disease are at times obscure. A reliable biochemical diagnostic method for aortic dissection would be beneficial.

METHODS AND RESULTS

A novel biochemical diagnostic method for diagnosis of aortic dissection was developed that uses an immunoassay of monoclonal antibodies to smooth muscle myosin heavy chain. A prospective study was conducted to ascertain the usefulness of the method in the diagnosis of aortic dissection. Twenty-seven patients with aortic dissection admitted within the first 24 hours after onset were enrolled. Serial assay of serum smooth muscle myosin heavy chain showed significant elevations within the first 24 hours after onset of aortic dissection, with levels exceeding 10 ng/mL, with subsequent rapid reductions. The sensitivity of the assay within the first 12 hours was 90% with a specificity of 97%. Analysis of 65 patients with acute myocardial infarction showed that the method could accurately differentiate myocardial infarction from aortic dissection.

CONCLUSIONS

The immunoassay of serum smooth muscle myosin heavy chain is a rapid and reliable biochemical method in the diagnosis of aortic dissection. The potential use of the method in clinical medicine is promising.

Preferential differentiation of P19 mouse embryonal carcinoma cells into smooth muscle cells. Use of retinoic acid and antisense against the central nervous system-specific POU transcription factor Brn-2

Investigation of the molecular mechanisms that control smooth muscle cell (SMC) development and differentiation is a prerequisite in understanding the regulatory mechanisms of physiological and pathological SMC-associated vascular processes. The pluripotent murine embryonal carcinoma P19 cell, whose developmental potential resembles that of early embryonic cells, can develop into cell types derived from the neuroectoderm, mesoderm, and endoderm. In the present study, we have shown a unique strategy to enhance SMC differentiation in P19 cells. Under chemical induction of high concentrations of retinoic acid (1 micromol/L), P19 cells showed optimum differentiation into SMCs. Because the P19 cells thus induced also showed differentiation into neuronal cells, a strategy to block neuronal lineage differentiation was developed using a stable transformant antisense RNA construct against Brn-2, a neuronal lineage-specific POU-domain transcription factor; thus, by specifically inhibiting neuronal differentiation, enhanced SMC differentiation by P19 cells was attained. SMC expression was confirmed by immunohistochemical staining, RNA analysis (RNase protection assay), and protein analysis (Western blot) using SMC-specific markers (eg, SM1 and calponin) and alpha-smooth muscle actin. Our results show that the pathway of SMC differentiation may provide an in vitro system useful in the investigation of SMC regulatory mechanisms (eg, transcriptional regulation) and in the further understanding of SMC development and differentiation.