Reduced cell motility and enhanced focal adhesion contact formation in cells from FAK-deficient mice

The intracellular protein tyrosine kinase FAK (focal adhesion kinase) was originally identified gy its high level of tyrosine phosphorylation in v-src-transformed cells. FAK is also highly phosphorylated during early development. In cultured cells it is localized to focal adhesion contacts and becomes phosphorylated and activated in response to integrin-mediated binding of cells to the extracellular matrix, suggesting an important role in cell adhesion and/or migration. We have generated FAK-deficient mice by gene targeting to examine the role of FAK during development. Mutant embryos displayed a general defect of mesoderm development, and cells from these embryos had reduced mobility in vitro. Surprisingly, the number of focal adhesions was increased in FAK-deficient cells, suggesting that FAK may be involved in the turnover of focal adhesion contacts during cell migration.

NF-kappaB binds P-TEFb to stimulate transcriptional elongation by RNA polymerase II

To stimulate transcriptional elongation of HIV-1 genes, the transactivator Tat recruits the positive transcription elongation factor b (P-TEFb) to the initiating RNA polymerase II (RNAPII). We found that the activation of transcription by RelA also depends on P-TEFb. Similar to Tat, RelA activated transcription when tethered to RNA. Moreover, TNF-alpha triggered the recruitment of P-TEFb to the NF-kappaB-regulated IL-8 gene. While the formation of the transcription preinitiation complex (PIC) remained unaffected, DRB, an inhibitor of P-TEFb, prevented RNAPII from elongating on the IL-8 gene. Remarkably, DRB inhibition sensitized cells to TNF-alpha-induced apoptosis. Thus, NF-kappaB requires P-TEFb to stimulate the elongation of transcription and P-TEFb plays an unexpected role in regulating apoptosis.

Tat competes with CIITA for the binding to P-TEFb and blocks the expression of MHC class II genes in HIV infection

AIDS and the bare lymphocyte syndrome (BLS) are severe combined immunodeficiencies. BLS results from mutations in genes that regulate the expression of class II major histocompatibility (MHC II) determinants. One of these is the class II transactivator (CIITA). HIV and its transcriptional transactivator (Tat) also block the expression of MHC II genes. By binding to the same surface in the cyclin T1, which together with CDK9 forms the positive transcription elongation factor b (P-TEFb) complex, Tat inhibits CIITA. CIITA can also activate transcription when tethered artificially to RNA. Moreover, a dominant-negative CDK9 protein inhibits the activity of MHC II promoters. Thus, CIITA is a novel cellular coactivator that binds to P-TEFb for the expression of its target genes.

Interactions between the class II transactivator and CREB binding protein increase transcription of major histocompatibility complex class II genes

Class II major histocompatibility (class II) genes are regulated in a B-cell-specific and gamma interferon-inducible fashion. The master switch for the expression of these genes is the class II transactivator (CIITA). In this report, we demonstrate that one of the functions of CIITA is to recruit the CREB binding protein (CBP) to class II promoters. Not only functional but also specific binding interactions between CIITA and CBP were demonstrated. Moreover, a dominant negative form of CBP decreased the activity of class II promoters and levels of class II determinants on the surface of cells. Finally, the inhibition of class II gene expression by the glucocorticoid hormone could be attributed to the squelching of CBP by the glucocorticoid receptor. We conclude that CBP, a histone acetyltransferase, plays an important role in the transcription of class II genes.

New restriction endonucleases from Flavobacterium okeanokoites (FokI) and Micrococcus luteus (MluI)

Two new restriction endonucleases have been isolated from Flavobacterium okeanokoites IFO12536 and Micrococcus luteus IFO12992 and named FokI and MluI, respectively. Based on analysis of the sequences around the restriction sites, the recognition sequences and cleavage sites of these endonucleases were deduced as below: FokI: (formula: see text). MluI introduces double-strand cleavages at unique sequences that are completely two-fold rotationally symmetric like most type II restriction endonucleases. FokI belongs to a class of restriction endonucleases that recognize specific but asymmetric nucleotide sequences and introduce staggered cleavages at appointed positions away from the recognition sequences.

Effects of efonidipine on platelet and monocyte activation markers in hypertensive patients with and without type 2 diabetes mellitus

We compared the levels of microparticles, platelet activation markers, soluble cell adhesion molecules, and soluble selectins between hypertensive patients with and without type 2 diabetes and control subjects. Binding of anti-glycoprotein IIb/IIIa and anti-glycoprotein Ib monoclonal antibodies to platelets did not differ significantly between the hypertensive patients and controls, but platelet expression of activation markers (CD62P, CD63, PAC-1, and annexin V) was higher in the hypertensive patients. Platelet-derived microparticle (PDMP) and monocyte-derived microparticle (MDMP) levels were significantly higher in the hypertensive patients than in the controls. Soluble ICAM-1, VCAM-1, P-selectin, and E-selectin levels were also higher in the hypertensive patients, and they were significantly higher in the hypertensive patients with diabetes. After treatment with efonidipine, the levels of PDMPs, CD62P-, CD63-, PAC-1-, and annexin V-positive platelets, sICAM-1, sVCAM-1, sP-selectin, and sE-selectin all decreased significantly. The MDMP levels decreased, and the decrease was significant in the hypertensive patients with diabetes. These findings suggest that administration of efonidipine to hypertension patients with diabetes may prevent the development of cardiovascular complications caused by cell adhesion molecules or activated platelets and monocytes.

Myocardial stiffness derived from end-systolic wall stress and logarithm of reciprocal of wall thickness. Contractility index independent of ventricular size

The slope of the end-systolic pressure-volume relation (ESPVR) is useful in assessing acute changes in contractile state. However, a limitation of ESPVR is that its slope decreases progressively as ventricular size increases without this change necessarily indicating a change in contractile state. In this respect, an index of contractile function that is independent of ventricular size would have an obvious advantage. The exponential constant (k) of the end-systolic relation between wall stress (sigma) and the natural logarithm of the reciprocal of wall thickness [ln(1/H)], sigma = Cekln(1/H), corresponds to the stiffness constant of the myocardium (kSM), a contractile index that should be independent of ventricular size and geometry. To examine the size independence of kSM, we studied left ventricular kSM during beta-blockade (to stabilize inotropic state) in 25 normal dogs with greatly differing ventricular sizes whose end-diastolic volumes ranged from 14 to 82 ml. The kSM was nearly constant (3.6 +/- 0.4) over this wide range of end-diastolic volumes and thus was independent of end-diastolic volume. Conversely, ESPVR, also obtained during beta-blockade, was closely and negatively correlated to end-diastolic volume (r = 0.92). To test the ability of kSM to measure changes in contractile state, we altered contractile state pharmacologically. The kSM increased from 3.7 +/- 0.5 to 4.8 +/- 0.8 (p less than 0.01) with infusion of dobutamine (after reversal of beta-blockade) and decreased to 3.1 +/- 0.3 (p less than 0.05) with inhalation of isoflurane, a negative inotrope, during beta-blockade (p less than 0.05). We conclude that kSM is independent of ventricular size and is sensitive to changes in inotropic state. As such, it should be useful as an index of contractile function.

VEGF, basic-FGF, and TGF-beta in Crohn's disease and ulcerative colitis: a novel mechanism of chronic intestinal inflammation

OBJECTIVE

Inflammatory bowel disease (IBD), the precise etiology of which remains unknown, is comprised of two forms of chronic intestinal inflammation; ulcerative colitis (UC) and Crohn's disease (CD). Recent evidence increasingly suggests that IBD is the result of dysfunctional immunoregulation manifested by inappropriate production of mucosal cytokines. An abnormal microcirculatory system has also been implicated in its pathogenesis. To elucidate the mechanism of ischemic change in IBD, we assesse serum concentration levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF), and plasma level of endothelin-1 (ET-1). We also investigated the expression of VEGF, b-FGF, and transforming growth factor-beta1,2,3 (TGF-beta1,2,3) in tissue by immunostaining.

METHODS

Blood samples were obtained from 11 patients with UC, 11 patients with CD, and 10 patients as controls. Paraffin-embedded samples were used for an immunohistochemical study.

RESULTS

The concentration levels (in picograms per milliliter) were as follows: for ET-1, UC: 127+/-47.0, CD: 167.3+/-35.1, and controls (asthma: 38.5+/-23.8, p < 0.01; diverticulitis: 40.5+/-25.6, p < 0.01), for b-FGF, UC: 9.2+/-1.9, CD: 9.1+/-1.5, and controls (asthma: 5.0+/-0, p < 0.01; diverticulitis: 5.0+/-0, p < 0.01), for VEGF, UC: 659.8+/-181.0, CD: 740.0+/-182.3, and controls (asthma: 193.7+/-58.7, p < 0.01; diverticulitis: 199.6+/-59.7, p < 0.01). The levels of VEGF and b-FGF were significantly higher in active IBD than those in the controls. There was a significant positive correlation among the serum levels of VEGF and b-FGF and the plasma level of ET-1; that is, elevated VEGF, b-FGF, and ET-1 levels correlated well with each other. Immunohistochemical studies showed increased venula in the submucosa and lamina propria. Overexpression of VEGF and b-FGF in endothelial cells was revealed and TGF-beta2 and TGF-beta3 were found in inflammatory cells of active IBD, but no change was observed around the vessels in the controls.

CONCLUSIONS

It is suggested that the reciprocal reaction of these cytokines may contribute to angiogenesis in IBD b inducing intestinal ischemia through vasoconstriction.

Analysis of flow characteristics in poststenotic regions of the human coronary artery during bypass graft surgery

Poststenotic blood flow velocities were evaluated in nine patients with 75% to 99% stenosis of the left anterior descending coronary artery (LAD) during coronary artery bypass graft surgery. We used the 20 MHz 80-channel pulsed Doppler velocimeter developed in our laboratory. An operator placed a specially designed probe on the native LAD with his fingers. Before induction of extracorporeal circulation, LAD blood velocities were measured at several locations distal to the stenosis. The poststenotic flow velocities were rich in systolic flow component with reduced diastolic component. The velocity configuration in the poststenotic portions was characterized by the presence of reverse flow velocities and/or irregularity of the velocity pattern near the vessel wall, indicating the existence of flow separation and recirculation in the regions. The broadening of the velocity spectrum observed at central axial regions suggested the occurrence of flow disturbances. After grafting, the velocity waveform in the LAD beyond a vein bypass graft changed to a diastolic-predominant pattern with a relatively small systolic component. A transient bypass graft occlusion caused a marked reduction in diastolic flow velocity. The systolic-to-diastolic velocity ratio increased from 0.27 +/- 0.07 to 1.50 +/- 0.50 (p less than .01) by the graft occlusion.

Depressed contractile function due to canine mitral regurgitation improves after correction of the volume overload

It is known that long-standing volume overload on the left ventricle due to mitral regurgitation eventually leads to contractile dysfunction. However, it is unknown whether or not correction of the volume overload can lead to recovery of contractility. In this study we tested the hypothesis that depressed contractile function due to volume overload in mitral regurgitation could return toward normal after mitral valve replacement. Using a canine model of mitral regurgitation which is known to produce contractile dysfunction, we examined contractile function longitudinally in seven dogs at baseline, after 3 mo of mitral regurgitation, 1 mo after mitral valve replacement, and 3 mo after mitral valve replacement. After 3 mo of mitral regurgitation (regurgitant fraction 0.62 +/- 0.04), end-diastolic volume had nearly doubled from 68 +/- 6.8 to 123 +/- 12.1 ml (P less than 0.05). All five indices of contractile function which we examined were depressed. For instance, maximum fiber elastance (EmaxF) obtained by assessment of time-varying elastance decreased from 5.95 +/- 0.71 to 2.25 +/- 0.18 (P less than 0.05). The end-systolic stiffness constant (k) was also depressed from 4.2 +/- 0.4 to 2.1 +/- 0.3. 3 mo after mitral valve replacement all indexes of contractile function had returned to or toward normal (e.g., EmaxF 3.65 +/- 0.21 and k 4.2 +/- 0.3). We conclude that previously depressed contractile function due to volume overload can improve after correction of the overload.

Specific binding of erythropoietin to its receptor on responsive mouse erythroleukemia cells

Erythropoietin (Epo) is a glycoprotein factor that specifically regulates the proliferation and differentiation of erythroid progenitor cells. Here we describe the isolation of Epo-responsive mouse erythroleukemia cell line SKT6, the characterization of the specific binding of biologically active 125I-labeled human Epo (125I-Epo) to its membrane receptor, and, finally, report information concerning the molecular structure of the receptor. About 75% of erythroid colony-forming precursor cell-like colonies derived from SKT6 cells were hemoglobin-positive after 3- to 4-day exposure to Epo in methylcellulose culture. Radioiodinated Epo bound specifically to SKT6 cells, and Scatchard analysis of the data showed a high affinity for 125I-Epo (Kd = 0.15 nM) but displayed only a small number of specific receptors (approximately equal to 470 per cell). Membrane components that specifically interact with 125I-Epo were identified by covalent crosslinking with disuccinimidyl suberate, and three receptor species with apparent Mr 63,000, 94,000, and 119,000 were found in membrane from SKT6 cells, suggesting the complex structure of the receptor molecules. Specific bindings were also detected in all of the Epo-unresponsive Friend erythroleukemia cells examined, and cross-linking study revealed the presence of only the 63,000 species as a binding site.

Essential role of phosphatidylserine externalization in apoptosing cell phagocytosis by macrophages

In many apoptotic cells, phosphatidylserine (PS), that is normally restricted to the inner membrane layer, is externalized and subsequently recognized by phagocytes. However, it has been unclear whether PS externalization is sufficient for phagocytosis induction. In a cultured cell line undergoing Fas-mediated apoptosis, PS externalization preceded other apoptotic events. When transbilayer movement of membrane phospholipids was analyzed, a decrease of the uptake of PS and phosphatidylethanolamine and an increase of phosphatidylcholine incorporation were observed upon apoptosis induction. Apoptotic cultured cells were phagocytosed by macrophages in a manner dependent on externalized PS before plasma membrane permeability increased. Moreover, a N-ethylmaleimide treatment caused PS externalization independent of apoptosis, and such cells underwent PS-mediated phagocytosis. These results suggested that PS is externalized as a result of membrane phospholipid redistribution and externalized PS by itself induces apoptosing cell phagocytosis.

The effect of various chemotherapeutic agents given with mild hyperthermia on different types of tumours

It has been shown that hyperthermia can enhance the cytotoxicity of some chemotherapeutics. However, the most effective agent(s) at elevated temperatures have yet to be determined. A previous study suggests that the drug of choice at elevated temperatures may be different from that at the physiological temperature, and that the alkylating agents may be most effective at elevated temperatures. To further investigate these possibilities, the effect of chemotherapeutic agents were compared. These agents were cyclophosphamide, ifosfamide, melphalan, cis-diamminedichloroplatinum (II), 5-fluorouracil, mitomycin C and bleomycin. Three tumours (mammary carcinoma, osteosarcoma and squamous cell carcinoma) were used. They were transplanted into the feet of C3H/He mice. When tumours reached 65 mm(3), a test agent was injected intraperitoneally. Tumours were immediately heated at 41.5 degrees C for 30 min, and the tumour growth (TG) time was studied for each tumour. Using the TG times, the TG-50 (the time required for one-half of the total number of the treated tumours to reach the volume of 800 mm(3) from 65 mm(3)) was calculated. Subsequently, the tumour growth delay time (GDT) and the thermal enhancement ratio (TER) were obtained. The GDT was the difference between the TG-50 of treated tumours and that of non-treated control tumours. The TER was the ratio of the GDT of a group treated with an agent at 41.5 degrees C to that of a group treated with the agent at room temperature. Results showed that the top three effective agents tested at 41.5 degrees C were solely alkylating agents--CY, IFO and L-PAM--for each kind of tumour. A GDT of cisplatin was smaller than those of the alkylating agents. The smallest TER, 1.1, was observed for 5-fluorouracil, which was given for mammary carcinoma, and for mitomycin C, which was given for squamous cell carcinoma. It could be concluded that the alkylating agents at elevated temperatures might be the drugs of choice for many types of tumours. The possible mechanisms of thermal enhancement associated with these agents are discussed.

Judgment of gender through facial parts

Japanese male and female undergraduate students judged the gender of a variety of facial images. These images were combinations of the following facial parts: eyebrows, eyes, nose, mouth, and the face outline (cheek and chin). These parts were extracted from averaged facial images of Japanese males and females aged 18 and 19 years by means of the Facial Image Processing System. The results suggested that, in identifying gender, subjects performed identification on the basis of the eyebrows and the face outline, and both males and females were more likely to identify the faces as those of their own gender. The results are discussed in relation to previous studies, with particular attention paid to the matter of race differences.

Impairment of mobility in endodermal cells by FAK deficiency

Focal adhesion kinase (FAK) is a novel nonreceptor protein tyrosine kinase that localizes in focal adhesions. It is expressed in a variety of cell types, and we reported earlier that is deficiency causes a decrease of mobility in mesodermal cells with enhanced formation of focal adhesions. With embryoid bodies generated from embryonic stem cells, we also observed a decrease of mobility in FAK-deficient endodermal cells with enhanced focal adhesion formation.

Endometrial carcinoma: dynamic MRI with turbo-FLASH technique

PURPOSE

Our goal was to investigate the usefulness of dynamic MRI with the turbo-FLASH technique in estimating myometrial invasion by endometrial carcinoma.

METHOD

Forty-six patients with endometrial carcinomas were evaluated with pathologic correlation. Dynamic MRI was performed with the rapid administration of Gd-DTPA using the turbo-FLASH technique.

RESULTS

The inner muscle layer showed more rapid contrast enhancement effects than the outer muscle layer even after menopause. Contrast-to-noise ratio between the inner muscle layer and endometrial carcinoma was maximum at approximately 50 s after administration of Gd-DTPA. In postmenopausal women, the accuracy in estimating myometrial invasion with T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MRI was 66.7, 77.8, and 92.6%, respectively.

CONCLUSION

Dynamic MRI with the turbo-FLASH technique is considered to be a useful imaging method for the estimation of myometrial invasion by endometrial carcinoma, especially in postmenopausal patients.

Comparison of blood-flow velocity waveforms in different coronary artery bypass grafts. Sequential saphenous vein grafts and internal mammary artery grafts

Characteristics of blood-flow velocities were investigated at different sites in two types of coronary artery bypass grafts, sequential saphenous vein grafts (SSVG) and internal mammary artery grafts (IMAG). The latter appear to have the longest life span. The patency rate of the side-to-side anastomosis of the SSVG is better than that of the end-to-side anastomosis. The SSVG was anastomosed to the major diagonal branch by side-to-side anastomosis and to the left anterior descending coronary artery (LAD) by end-to-side anastomosis in 13 patients who had 75-100% and 75-90% stenoses in the LAD and major diagonal branch, respectively. IMAG anastomoses were performed to the LAD in 10 patients with 75-100% stenoses of the artery. The blood-flow velocities were measured by the 20-MHz, eighty-channel ultrasound pulsed Doppler method during surgery. In six patients in the SSVG group, we investigated the configuration of velocity profiles at the region just proximal to the side-to-side anastomosis and at the bridge portion between the side-to-side and end-to-side anastomosis. In the other seven patients, we measured the blood-flow velocity at several centimeters proximal to the side-to-side anastomosis and compared it with that in the IMAG. At the region just proximal to the side-to-side anastomosis, the velocity profile skewed toward the anastomosis side wall in all patients, and the flow velocity near the wall opposite to the side-to-side anastomosis was reversed in five of six patients.(ABSTRACT TRUNCATED AT 250 WORDS)

ATR1, a Saccharomyces cerevisiae gene encoding a transmembrane protein required for aminotriazole resistance

In Saccharomyces cerevisiae, 3-amino-1,2,4-triazole (aminotriazole) competitively inhibits the activity of imidazoleglycerolphosphate dehydratase, the product of the HIS3 gene. Wild-type strains are able to grow in the presence of 10 mM aminotriazole because they induce the level of imidazoleglycerolphosphate dehydratase. However, strains containing gcn4 mutations are unable to grow in medium containing aminotriazole because they lack the GCN4 transcriptional activator protein necessary for the coordinate induction of HIS3 and other amino acid biosynthetic genes. Here, we isolated a new gene, designated ATR1, which when present in multiple copies per cell allowed gcn4 mutant strains to grow in the presence of aminotriazole. In wild-type strains, multiple copies of ATR1 permitted growth at extremely high concentrations of aminotriazole (80 mM), whereas a chromosomal deletion of ATR1 caused growth inhibition at very low concentrations (5 mM). When radioactive aminotriazole was added exogenously, cells with multiple copies of ATR1 accumulated less aminotriazole than wild-type cells, whereas cells with the atr1 deletion mutation retained more aminotriazole. Unlike the mammalian mdr or yeast PDR genes that confer resistance to many drugs, ATR1 appears to confer resistance only to aminotriazole. Genetic analysis, mRNA mapping, and DNA sequencing revealed that (i) the primary translation product of ATR1 contains 547 amino acids, (ii) ATR1 transcription is induced by aminotriazole, and (iii) the ATR1 promoter region contains a binding site for the GCN4 activator protein. The deduced amino acid sequence suggests that ATR1 protein is very hydrophobic with many membrane-spanning regions, has several potential glycosylation sites, and may contain an ATP-binding site. We suggest that ATR1 encodes a membrane-associated component of the machinery responsible for pumping aminotriazole (and possibly other toxic compounds) out of the cell.

The effect of adaptive iterative dose reduction on image quality in 320-detector row CT coronary angiography

OBJECTIVE

To evaluate the effect of adaptive iterative dose reduction (AIDR) on image noise and image quality as compared with standard filtered back projection (FBP) in 320-detector row CT coronary angiography (CTCA).

METHODS

50 patients (14 females, mean age 68 ± 9 years) who underwent CTCA (100 kV or 120 kV, 400-580 mA) within a single heartbeat were enrolled. Studies were reconstructed with FBP and subsequently AIDR. Image noise, vessel contrast and contrast-to-noise ratio (CNR) in the coronary arteries were evaluated. Overall image quality for coronary arteries was assessed using a five-point scale (1, non-diagnostic; 5, excellent).

RESULTS

All the examinations were performed in a single heartbeat. Image noise in the aorta was significantly lower in data sets reconstructed with AIDR than in those reconstructed with FBP (21.4 ± 3.1 HU vs 36.9 ± 4.5 HU; p<0.001). No significant differences were observed between FBP and AIDR for the mean vessel contrast (HU) in the proximal coronary arteries. Consequently, CNRs in the proximal coronary arteries were higher in the AIDR group than in the FBP group (p<0.001). The mean image quality score was improved by AIDR (3.75 ± 0.38 vs 4.24 ± 0.38; p<0.001).

CONCLUSION

The use of AIDR reduces image noise and improves image quality in 320-detector row CTCA.

Scientific discoveries as cultural displays: a further test of Miller's courtship model

The biographies of 280 scientists demonstrate that the age distribution of their career peaks is identical to those of jazz musicians, painters, and writers, and that this universal age profile holds only among scientists who were married some time in their lives. I interpret this as support for Miller's cultural display model in an evolutionarily novel environment.

Parenchymal changes of the liver in cholangiocarcinoma: CT evaluation

We evaluated parenchymal changes of the liver in 92 patients (41 peripheral types and 51 hilar types) with cholangiocarcinomas studied by bolus-enhanced computed tomography (CT). In 39% of patients with the peripheral type, a wedge-shaped increased enhancement of the liver was observed peripheral to the tumor on bolus-enhanced CT. Tumor was observed in all cases. In 58.8% of patients with the hilar type, a segmental or lobar increased degree of enhancement of the liver was observed, but the tumor was demonstrated in only 58.8%. Atrophy was accompanied by areas of increased enhancement in 80% of hilar type and 25% of peripheral type. Areas of increased degree of enhancement corresponded to a wedged-shaped perfusion defect on CT during arterial portography. On magnetic resonance imaging (MRI), those lesions showed hyperintensity on T2-weighted images. Most of these changes were considered to be due to reversible hepatic parenchymal ischemia secondary to portal vein invasion by the tumor.

Preliminary report: effect of adrenal androgen and estrogen on bone maturation and bone mineral density

To clarify the independent physiological roles of adrenal androgen and estrogen on bone growth, we compared the lumbar spine bone mineral density (BMD) in prepubertal girls with virilizing congenital adrenal hyperplasia (CAH) (n = 17) and girls with central precocious puberty (CPP) (n = 18). When BMD was analyzed according to chronologic age, no significant differences were found between CPP and CAH patients. However, when adjusted to bone age, BMD was statistically higher in CAH than in CPP subjects. This finding suggests that adrenal androgen, as well as estrogen, plays an important role in increasing BMD. Adrenal androgen may act on bone not only as androgen, but as estrogen after having been metabolized into an aromatized bone-active compound in peripheral tissues, such as bone and fat. Therefore, adrenal androgen may have a more important role in increasing BMD than previously realized.

Novel human topoisomerase I inhibitors, topopyrones A, B, C and D. I. Producing strain, fermentation, isolation, physico-chemical properties and biological activity

In the course of a screening program for specific inhibitors of human topoisomerase I using a recombinant yeast, we have discovered four new active compounds. All four compounds were isolated from the culture broth of a fungus, Phoma sp. BAUA2861, and two of them were isolated from the culture broth of a fungus, Penicillium sp. BAUA4206. We designated these compounds as topopyrones A, B, C and D. Topopyrones A, B, C and D selectively inhibited recombinant yeast growth dependent on expression of human topoisomerase I with IC50 values of 1.22, 0.15, 4.88 and 19.63 ng/ml, respectively. The activity and selectivity of topopyrone B were comparable to those of camptothecin. The relaxation of supercoiled pBR322 DNA by human DNA topoisomerase I was inhibited by these compounds, however they did not inhibit human DNA topoisomerase II. Topopyrones A, B, C and D were cytotoxic to all tumor cell lines when tested in vitro. Topopyrone B has potent inhibitory activity against herpesvirus, especially varicella zoster virus (VZV). It inhibited VZV growth with EC50 value of 0.038 microg/ml, which is 24-fold stronger than that of acyclovir (0.9 microg/ml). Topopyrones A, B, and C were inhibitory to Gram-positive bacteria.