Insulin-like growth factor 1 regulates developing brain glucose metabolism

The brain has enormous anabolic needs during early postnatal development. This study presents multiple lines of evidence showing that endogenous brain insulin-like growth factor 1 (Igf1) serves an essential, insulin-like role in promoting neuronal glucose utilization and growth during this period. Brain 2-deoxy-d- [1-(14)C]glucose uptake parallels Igf1 expression in wild-type mice and is profoundly reduced in Igf1-/- mice, particularly in those structures where Igf1 is normally most highly expressed. 2-Deoxy-d- [1-(14)C]glucose is significantly reduced in synaptosomes prepared from Igf1-/- brains, and the deficit is corrected by inclusion of Igf1 in the incubation medium. The serine/threonine kinase Akt/PKB is a major target of insulin-signaling in the regulation of glucose transport via the facilitative glucose transporter (GLUT4) and glycogen synthesis in peripheral tissues. Phosphorylation of Akt and GLUT4 expression are reduced in Igf1-/- neurons. Phosphorylation of glycogen synthase kinase 3beta and glycogen accumulation also are reduced in Igf1-/- neurons. These data support the hypothesis that endogenous brain Igf1 serves an anabolic, insulin-like role in developing brain metabolism.

Functional link of BRCA1 and ataxia telangiectasia gene product in DNA damage response

BRCA1 encodes a familial breast cancer suppressor that has a critical role in cellular responses to DNA damage. Mouse cells deficient for Brca1 show genetic instability, defective G2-M checkpoint control and reduced homologous recombination. BRCA1 also directly interacts with proteins of the DNA repair machinery and regulates expression of both the p21 and GADD45 genes. However, it remains unclear how DNA damage signals are transmitted to modulate the repair function of BRCA1. Here we show that the BRCA1-associated protein CtIP becomes hyperphosphorylated and dissociated from BRCA1 upon ionizing radiation. This phosphorylation event requires the protein kinase (ATM) that is mutated in the disease ataxia telangiectasia. ATM phosphorylates CtIP at serine residues 664 and 745, and mutation of these sites to alanine abrogates the dissociation of BRCA1 from CtIP, resulting in persistent repression of BRCA1-dependent induction of GADD45 upon ionizing radiation. We conclude that ATM, by phosphorylating CtIP upon ionizing radiation, may modulate BRCA1-mediated regulation of the DNA damage-response GADD45 gene, thus providing a potential link between ATM deficiency and breast cancer.

Prevalence of foam cells and helper-T cells in atherosclerotic plaques of Korean patients with carotid atheroma

BACKGROUND

Inflammation and activation of immune cells have important roles in the pathogenesis of atherosclerosis. We analyzed the involvement of various immune cells in the pathogenesis of atherosclerosis.

METHODS

We investigated the presence of foam cells, lymphocytes and killer cells in 11 atherosclerotic plaque specimens removed from Korean patients who underwent carotid endoarterectomy. Atherosclerotic plaques were analyzed by immunohistochemistry using monoclonal antibody specific to foam cells (anti-CD68), pan-T cells (anti-CD3), helper-T cells (anti-CD4), cytotoxic T cells (anti-CD8), granular component of killer cells (anti-TIA-1) and pan-B cells (anti-CD20).

RESULTS

Analysis revealed a general infiltration of immune cells not only in atherosclerotic plaques but also in the vascular wall adjacent to the plaque. Heavy infiltration of CD68+ macrophage was observed in all cases. In addition, significant infiltration of CD3+ T-lymphocytes was observed in all cases, while CD20+ B-cells were observed in only a few cases. Majority of the CD3+ cells was found to be CD4+ helper-T cells. CD8+ cytotoxic T cells and TIA-1+ cells were less prominent.

CONCLUSION

Analysis of the human atherosclerotic plaques suggested that helper-T cells and foam cells had a major role in the plaque development.

Malignant meningioma with rhabdoid transformation

We report a rare case of recurrent meningioma with malignant change and rhabdoid transformation in a 54-year-old woman who presented with severe headache and progressive weakness of the right extremities. The patient had a history of atypical meningioma and had undergone a craniotomy to remove a tumor nine years earlier. We discuss the distinctive morphologic, immunohistochemical staining and ultrastructural features of a recurrent malignant meningioma. A meningioma with rhabdoid transformation may indicate aggressive biologic and clinical behavior of the tumor.

Histopathological examination of chemo-sympathectomy in cats

In recent decades, there has been an increase in both the number of sympathectomy techniques, as well as the surgical findings of sympathetic anatomy. Currently the advanced technique of C-arm guided percutaneous thoracic chemo-sympathectomy is widely used for the treatment of palmar hyperhidrosis. However, a better understanding of chemical agents in sympathectomy is required. In this study, chemo-sympathectomy was performed in cats, using alcohol, glycerol and various concentrations of phenol, to determine the chronic neurotoxic effects of these chemical agents on the stellate ganglia. The stellate ganglia of 24 cats were exposed under endotracheal general anesthesia, then injected with about 0.02 ml of absolute alcohol, glycerol and phenol (10%, 25%, 50%, and 75% concentration) solutions, respectively. The stellate ganglia were taken for histological examination three weeks after the chemical injection. The results showed that the degenerative changes in the cytoplasm and nucleus of ganglionic cells and intercellular tissue were moderate and relatively moderate after the injection of alcohol and glycerol, respectively. Meanwhile, the stellate ganglia revealed mild, relatively moderate, serious and extremely serious degeneration after injection of 10%, 25%, 50%, and 75% phenol, respectively. In conclusion, we recommend a high concentration of phenol, in the least volume, as a chemical agent for clinical injection in the upper thoracic sympathetic ganglion.

Comparison of the efficacy and safety of latanoprost 0.005% compared to brimonidine 0.2% or dorzolamide 2% when added to a topical beta-adrenergic blocker in patients with primary open-angle glaucoma or ocular hypertension

The purpose of this study was to evaluate the ocular hypotensive efficacy and safety of latanoprost 0.005% (Xalatan, Pharmacia & Upjohn), brimonidine (Alphagan, Allergan), and dorzolamide (Trusopt, Merck Inc.) when added to a beta-blocker in patients with ocular hypertension or primary open-angle glaucoma. This was a multicenter, retrospective analysis which included all reviewed patient records in which latanoprost, brimonidine or dorzolamide were added to a beta-blocker for at least three months. Patients who were treated for less than three months, who failed therapy due to ineffectiveness of the medicine or an adverse event also were included. The study included 141 patients. Latanoprost (n = 50) showed an intraocular pressure of 16.7 +/- 3.3 mm Hg (-6.3 +/- 4.1 mm Hg, P < 0.001), brimonidine (n = 24) 17.4 +/- 4.9 mm Hg (-4.2 +/- 4.5 mm Hg, P < 0.001), and dorzolamide (n = 67) 20.1 +/- 6.1 mm Hg (-3.1 +/- 5.1 mm Hg, P < 0.001) at three months. A significant difference was observed in the absolute level of intraocular pressure (P < 0.005) and the change from baseline between groups (P < 0.005) at three months. A significant difference was observed between groups in the success rate of therapy between latanoprost (70%), brimonidine (58%) and dorzolamide (40%) (P = 0.008). No significant differences were observed between groups for rate or type of adverse events leading to discontinued therapy. This study showed that latanoprost, when added to beta-blockers, compares favorably in ocular hypotensive efficacy and is similar in safety to brimonidine and dorzolamide.

Retinoblastoma protein enhances the fidelity of chromosome segregation mediated by hsHec1p

Retinoblastoma protein (Rb) plays important roles in cell cycle progression and cellular differentiation. It may also participate in M phase events, although heretofore only circumstantial evidence has suggested such involvement. Here we show that Rb interacts, through an IxCxE motif and specifically during G(2)/M phase, with hsHec1p, a protein essential for proper chromosome segregation. The interaction between Rb and hsHec1p was reconstituted in a yeast strain in which human hsHEC1 rescues the null mutation of scHEC1. Expression of Rb reduced chromosome segregation errors fivefold in yeast cells sustained by a temperature-sensitive (ts) hshec1-113 allele and enhanced the ability of wild-type hsHec1p to suppress lethality caused by a ts smc1 mutation. The interaction between Hec1p and Smc1p was important for the specific DNA-binding activity of Smc1p. Expression of Rb restored part of the inactivated function of hshec1-113p and thereby increased the DNA-binding activity of Smc1p. Rb thus increased the fidelity of chromosome segregation mediated by hsHec1p in a heterologous yeast system.

Methylation of the neutral endopeptidase gene promoter in human prostate cancers

Neutral endopeptidase 24.11 (NEP) is a cell surface peptidase expressed by prostatic epithelial cells that cleaves and inactivates neuropeptide growth factors implicated in the growth of androgen-independent prostate cancer (PC). Decreased NEP expression in hormone-refractory metastatic PCs can result from hormonal therapies because NEP transcription is induced by androgens and down-regulated by androgen withdrawal. NEP is encoded by a gene that contains a 5' CpG island spanning a transcriptional regulatory region. In this study, we investigate whether DNA hypermethylation of the NEP promoter accompanies decreased NEP expression in PC cell lines and whether it occurs in human PC tissues in vivo. DNA isolated from PC cell lines and from normal and neoplastic human prostate tissues was restriction-digested with a methylation-sensitive restriction endonuclease and analyzed by Southern blot using a 5' sequence-specific NEP probe. Methylation-specific PCR was performed using PCR primers designed to discriminate between methylated and unmethylated alleles, and reverse transcription-PCR using NEP-specific primers was performed on cDNA extracted from PC cells treated with 5-aza-2'-deoxycytidine. Methylation of the NEP promoter was present in androgen-independent PC cell lines but not in androgen-dependent or small-cell derived PC cell lines and in 3 of 21 (14%) primary PCs from patients with androgen-dependent disease. Exposure of PC cells to the demethylating agent 5-aza-2'-deoxycytidine led to an increase in NEP transcripts in DU-145 and PC-3 cells. These data show that hypermethylation of the 5' CpG NEP island is associated with a loss of NEP expression in PC. Loss of NEP expression via hypermethylation of the NEP promoter may contribute to the development of neuropeptide-stimulated PCs.

CD40L activation in circulating platelets in patients with acute coronary syndrome

The CD40-CD40L interaction, which was initially shown to have important roles in the T cell-mediated activation of B cells during humoral immune responses, is now known to have roles in activation of endothelial cells, smooth muscle cells, and macrophages within atherosclerotic plaques. Recently, CD40L expression was found in activated platelets in the thrombus in vivo and CD40L was reported to be responsible for the platelet-mediated activation of endothelial cells in vitro. To investigate the activation status of platelets in coronary artery disease patients, we tested expression levels of CD40L, and platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31) in platelets isolated from peripheral blood, using flow cytometric analysis. Twenty-nine patients with acute coronary syndrome (10 acute myocardial infarction and 19 unstable angina patients) were compared with 14 normal subjects or 14 stable angina patients. In platelets isolated from normal subjects, the expression of CD40L was not detected in all subjects. In the patients with acute coronary syndrome, the average level of CD40L showed a significant increase (p = 0.0028), while stable angina patients did not have any increase when compared to normal subjects. Patients with more complex lesions or vessel occlusion tended to have a high platelet CD40L level compared to patients who do not. The expression levels of CD31 were increased in a small portion of the ACS patients. These data indicate that the rupture of plaque and subsequent formation of thrombus may lead to the activation of CD40L expression in circulating platelets of ACS patients.

Characterization of a highly glycopeptide-resistant Enterococcus gallinarum isolate

BACKGROUND AND PURPOSE

Adequate treatment of emergency infection involving antibiotic-resistant bacteria such as vancomycin-resistant Enterococcus requires a convergence of clinical and bacteriologic techniques. An isolate of Enterococcus gallinarum, designated as TSGH63, is known to be uncommonly vancomycin-resistant. This study investigated the genetic determinant for this unique characteristic.

METHODS

After completing the conventional identification and sensitivity tests, the genomic content of E. gallinarum TSGH63 was extracted and analyzed by pulse-field electrophoresis. A set of specific primers for vanA, vanB, vanC1, and vanC2/C3 genes was then applied in a multiplex polymerase chain reaction (PCR) to differentiate its genetic content. To locate the determinant for high vancomycin resistance, the electrophoresis profile was further analyzed by Southern blot using the digoxigenin (DIG)-labeled vanA gene probe. Finally, interspecies transfer of the vancomycin-resistance determinant of E. gallinarum TSGH63 was tested by a conjugation experiment in vitro.

RESULTS

A 50-kb plasmid was identified in the analysis of the genomic extract of E. gallinarum TSGH63 by pulse field electrophoresis. Using multiplex PCR, we demonstrated that E. gallinarum TSGH63 harbors a vanA gene in addition to a vanC1 gene. The DIG-labeled vanA gene-specific probe bound to the plasmid exclusively on the Southern blot. The plasmid-carried vanA gene, but not the vanC1 gene, was found to be transferable from TSGH63 to E. faecalis JH2-2 by conjugation in vitro.

CONCLUSIONS

This is the first report of isolation of E. gallinarum with a high level of resistance to glycopeptides in Taiwan. The demonstrated interspecies transfer of the vancomycin-resistance gene highlights the importance of stringent control of the use of vancomycin.

Masturbation and its relationship to sexual activities of young males in Korean military service

This study examined the masturbatory experiences and other sexual activities of young Korean males in military service. The actual status of masturbation and its relationship to sexual activity questionnaire. A total of 1,212 young males among military personnel in Korea were interviewed with sexuality questionnaires on masturbation, sexual intercourse and personal characteristics. We divided these subjects into four groups according to the age of initiation of masturbation and analyzed the relationship between masturbation and other sexual activities. The mean age of subjects was 22.03 +/- 1.22 (19-27) years. The percentage of men who reported ever having masturbated was 98.1% (1189/1212) and the average age of initiation of masturbation was 14.26 +/- 1.66 years. So we divided 1,212 males into four groups on the basis of the average age below and above one standard deviation. Overall, 67.7% (821/1212) had experienced sexual intercourse, and significantly, the earlier the initiation age of masturbation, the higher the coitus rate in each group (p < 0.05). About 21.5% of the men who were not virgins had experienced their first sexual intercourse with prostitutes. The mean age of first coitus, the incidence of sexually transmitted disease (STD) and the frequency of masturbation were closely linked to the initiation age of masturbation, respectively (p < 0.05). A masturbatory guilt feeling was seen in about 10.9% (132/1212) and there was no significant difference according to the types of religious worship (p = 0.227). On the basis of this study, sexual activities generally increased accordingly as the beginning of masturbation was earlier. Coital incidence in this study was 67.7% for young males in Korean military service, and 21.5% of them had their first sexual intercourse with prostitutes. Prostitution still plays an important role in the sexual lives of males in Korea. The incidence of STD was over 10% and homosexual manifestation was seen in 1.07% of subjects. Thus a proper and sound sex education at school during childhood is needed in Korea. A large scale survey of sexual behavior in various populations is essential for the improvement of correct sexual concepts.

Multicenter study of the treatment of erectile dysfunction with transurethral alprostadil (MUSE) in Korea

A Korean multicenter study was conducted to assess the effectiveness of transurethral alprostadil with MUSE in 334 subjects with chronic erectile dysfunction (ED) who were enrolled in 21 clinical centers. Patients with psychogenic impotence comprised about 30% of subjects. Intraurethral alprostadil was titrated in a stepwise fashion in the clinics from 250 to 500 or 1000 mcg based on erectile response and tolerability. The erectile responses were evaluated using an erection assessment scale (score of 1-5). The dose that produced a maximal penile response of score 5 (full rigid erection) or 4 (full tumescence, partial rigidity) was selected for home treatment. Patients who showed partial erection (score of 3) with 1000 mcg were also included in the home-treatment group. In-clinic phase: 198 men (59.3%) had maximal penile responses of score 4 or 5. The rate of maximal responses was not related to patient age, etiology or duration of the ED. A total of 228 (68.3%) men progressed to home treatment. The overall level of comfort of the transurethral alprostadil was rated as uncomfortable or very uncomfortable in 12%. Home phase: During the two-month period of home treatment, 178 (78.1%) men had successful sexual intercourse at least once, and 78.2% of administrations (1976) resulted in successful intercourse. The main causes of drop-out were insufficient erectile response in 27 men (11.8%), adverse reactions (mostly penile or urethral pain) in 7 (3.1%) or both in 7 (3.1%). In conclusion, transurethral alprostadil could be a suitable treatment option for patients with ED regardless of age and etiology of ED. Efficacy in an Asian population (Korea) is comparable to that reported previously in Caucasians.

A paradigm for cancer treatment using the retinoblastoma gene in a mouse model

Discovery of tumor suppressor genes has provided a rational approach to cancer prevention and treatment. Loss of retinoblastoma susceptibility gene (Rb) function is a rate-limiting event in the development of human and mouse cancers. Establishment of animal models of cancer associated with Rb deficiency allowed us to develop and test long-awaited approaches to genetic correction for treating tumors in vivo. Recent studies demonstrated that (1) prevention of carcinogenesis is achieved by correction of gene copy number in Rb+/- mice, and (2) reconstitution of Rb gene functions is sufficient for suppression of neoplasia in immunocompetent mice. These results fulfill a promise of cancer treatment by reconstitution of tumor suppressor function.

Clinical study of SS-cream in patients with lifelong premature ejaculation

OBJECTIVES

To investigate the clinical efficacy of SS-cream, the topical agent made from the extracts of nine natural products for the treatment of premature ejaculation, we performed a double-blind, randomized, placebo-controlled Phase III clinical study of patients with lifelong premature ejaculation in three medical centers.

METHODS

One hundred six patients (mean age 38.7 +/- 0.61 years) completed this study. The ejaculatory latency measured by stopwatch and sexual satisfaction ratio of both partner and patient were investigated twice in the screening period and once after each treatment (1 placebo 0.20 g and 5 SS-cream 0.20 g for a total of six treatments). Patients were instructed to apply the cream on the glans penis 1 hour before sexual intercourse in a double-blind randomized fashion. Clinical efficacy was compared with the prolongation of ejaculatory latency and improvement of the sexual satisfaction ratio before and after each treatment.

RESULTS

In the screening period, the mean ejaculatory latency was assessed at 1.37 +/- 0.12 minutes, and neither the patients nor their partners were satisfied with their sexual lives. After treatment, the mean ejaculatory latency was prolonged to 2.45 +/- 0.29 minutes in the placebo group and 10.92 +/- 0.95 minutes in the SS-cream group. The clinical efficacy of placebo and SS-cream as judged by an ejaculatory latency time prolonged more than 2 minutes was 15.09% and 79.81%, respectively. The improvement of sexual satisfaction to a grade higher than effective was 19.81% and 82.19%, respectively, for placebo and SS-cream. Of 530 trials of SS-cream, 98 (18.49%) resulted in a sense of mild local burning and mild pain. No adverse effect on sexual function or partner and no systemic side effects were observed.

CONCLUSIONS

According to these results, SS-cream is effective and safe in the treatment of premature ejaculation, with mild local side effects.

Characterization of the first clinical isolate of vancomycin-resistant Enterococcus faecalis, AH803, in Taiwan

We previously isolated a vancomycin-resistant strain of Enterococcus faecalis, designated AH803, from the sputum of a patient with pneumonia and bacteremia in Taiwan. AH803 was resistant to vancomycin (minimal inhibitory concentration, MIC = 512 micrograms/mL) but susceptible to teicoplanin (MIC = 8 micrograms/mL), and harbored the vanA gene but not the vanB gene. In this study, we further characterized E. faecalis AH803 and the plasmid it was found to contain. DNA from AH803 was analyzed for the presence of vanA and vanB resistance genes by polymerase chain reaction. The vancomycin resistant phenotype was transferable from AH803 to E. faecalis JH2-2, at a frequency of 4.8 x 10(-2). AH803 was also resistant to gentamicin and chloramphenicol, and these antibiotic resistance phenotypes cotransferred with vancomycin resistance. The genes responsible for resistance to all three antibiotics were located on a 42-kb conjugative plasmid (pBL101). This plasmid had the same restriction enzyme digestion patterns as Tn1546, found in pIP816 of E. faecalis BM4147. Epidemiologic studies of glycopeptide resistance should perhaps combine phenotypic and genotypic methods, rather than using phenotypic methods alone.

p53-independent induction of p21 (WAF1/CIP1), reduction of cyclin B1 and G2/M arrest by the isoflavone genistein in human prostate carcinoma cells

Genistein, a natural isoflavonoid phytoestrogen, is a strong inhibitor of protein tyrosine kinase and DNA topoisomerase II activities. Genistein has been shown to have anticancer proliferation, differentiation and chemopreventive effects. In the present study, we have addressed the mechanism of action by which genistein suppressed the proliferation of p53-null human prostate carcinoma cells. Genistein significantly inhibited the cell growth, which effect was reversible, and induced dendrite-like structure. The inhibitory effects of genistein on cell growth proliferation were associated with a G2/M arrest in cell cycle progression concomitant with a marked inhibition of cyclin B1 and an induction of Cdk inhibitor p21 (WAF1/CIP1) in a p53-independent manner. Following genistein treatment of cells, an increased binding of p21 with Cdk2 and Cdc2 paralleled a significant decrease in Cdc2 and Cdk2 kinase activity with no change in Cdk2 and Cdc2 expression. Genistein also induced the activation of a p21 promoter reporter construct, utilizing a sequence distinct from the p53-binding site. Analysis of deletion constructs of the p21 promoter indicated that the response to genistein could be localized to the 300 base pairs proximal to the transcription start site. These data suggest that genistein may exert a strong anticarcinogenic effect, and that this effect possibly involves an induction of p21, which inhibits the threshold kinase activities of Cdks and associated cyclins, leading to a G2/M arrest in the cell cycle progression.

Penile vibratory threshold changes with various doses of SS-cream in patients with primary premature ejaculation

SS-cream made with extracts from natural products is a topical agent for treating premature ejaculation (PE). In order to elucidate the penile vibratory threshold changes and clinical effects of various doses of SS-cream, 53 patients with primary PE were investigated in a double-blind randomized placebo-controlled study. The mean age was 37.3 +/- 6.4 years and mean ejaculatory latency was 1.37 +/- 0.52 minutes. Neither the patients nor their sexual partners were satisfied with their sexual lives. Vibratory threshold at the glans penis, penile shaft, scrotum and index finger were measured using a biothesiometer twice during the screening period and three times one hour after the application of respective creams (SS-cream 0.05, 0.10. 0.15, 0.20 gm and placebo 0.10 gm) on the glans penis according to the order of the allocation table in a randomized fashion. The efficacy of SS-cream was defined as when the vibration threshold increased by more than 4 microns compared to the value tested during the screening period. The vibratory thresholds at the glans penis increased significantly in a dose-dependent manner after the application of various doses (0.05, 0.10, 0.15, 0.20 gm) of SS-cream (p < 0.001), and the efficacy of SS-cream on the penile vibration threshold increased according to the increased dosage (penile shaft: 48.4, 51.6, 54.8, 64.5%, glans penis: 58.1, 67.7, 77.4, 83.9%, respectively). With these results, we concluded that SS-cream increased the penile sensory threshold dose dependently, and therefore it is clinically effective for treating the heightened penile sensory response in patients with PE.

Aging affects the association between endothelial nitric oxide synthase gene polymorphism and acute myocardial infarction in the Korean male population

OBJECTIVES

The aging process affects responsiveness and other functions of endothelium and vascular smooth muscle cells, predisposing the old vessels to the development of atherosclerotic lesions. Endothelial nitric oxide synthase (ecNOS) gene polymorphisms were shown to affect the occurrence of acute myocardial infarction (AMI). We hypothesized that aging may affect the association between the ecNOS gene polymorphism and AMI.

METHODS

We investigated the age-related distribution of the ecNOS gene a/b polymorphism in 121 male AMI patients and 206 age-matched healthy male controls.

RESULTS

The aa, ab and bb genotypes were found in 1, 49 and 156 cases among the control subjects and 5, 23 and 93 cases among the AMI patients, respectively. There was a significant correlation between the ecNOS polymorphism and AMI (p = 0.045). When the correlation was analyzed by age, the significance remained only in the group below the age of 51 (p = 0.009). The proportion of smokers was increased in the young patients when compared to the old patients (p = 0.033), indicating that smoking also has greater effect on the younger population. The incidences of hypertension and diabetes mellitus, however, were similar in both populations.

CONCLUSION

Our work provides the first evidence that links ecNOS polymorphism to the risk of AMI in relation to age. Young persons who smoke or have ecNOSaa genotype may have an increased risk of developing AMI. The functional as well as structural changes associated with aging in the vascular endothelium may mask the effect of the ecNOS polymorphism in the development of AMI in old persons.

Primary hemangiopericytoma of the tibia: MR and angiographic correlation

The Magnetic Resonance Imaging (MRI) appearances of primary osseous hemangiopericytoma (HPC) have been rarely described. We report on a 46-year-old Chinese man with primary osseous HPC of the right tibia. The characteristic vascular distribution of this tumor, presenting with a "spoke-wheel" appearance on MR images and with angiographic correlation, is described. Although not pathognomonic, this MR appearance may be an important finding in suggesting the diagnosis of osseous HPC.

Emerging roles of BRCA1 in transcriptional regulation and DNA repair

BRCA1 was the first breast cancer susceptibility gene to be identified and cloned. In individuals from high-risk families, mutations in BRCA1 increase the lifetime risk of developing breast cancer eight to tenfold, compared to the general population. How the BRCA1 protein product normally functions to suppress tumor formation and how defects in the gene can ultimately lead to breast cancer have been the focus of intense scrutiny by the scientific and medical communities. BRCA1 has intrinsic transactivation activity and is able to activate the p21 promoter. In addition, BRCA1 is linked to a number of genes involved in transcriptional regulation, including CtIP, c-Myc, the RNA holoenzyme complex, and the histone deacetylase complex. Moreover, BRCA1 is essential for cellular response to DNA damage repair. Inactivation of Brca1 in mouse embryonic stem and fibroblast cells results in increased cell sensitivity to DNA-damaging agents. In human cells, BRCA1 binds to both Rad50 and Rad51 and colocalizes with these proteins at repair foci. Part of BRCA1's response to DNA damage may in fact be corroborated through transcriptional regulation. The expression of GADD45, a DNA damage-responsive gene, is increased immediately after induction of BRCA1. Recently, BRCA1 was shown to repress estradiol (E2)-responsive ER-alpha-mediated transcriptional activity, potentially linking the multiple functions of BRCA1 to specific tissue targets. These recent developments in BRCA1 function are an encouraging step toward understanding the role of BRCA1 in breast cancer formation.

Expression of BRC repeats in breast cancer cells disrupts the BRCA2-Rad51 complex and leads to radiation hypersensitivity and loss of G(2)/M checkpoint control

BRCA2 is a breast tumor suppressor with a potential function in the cellular response to DNA damage. BRCA2 binds to Rad51 through its BRC repeats. In support of the biological significance of this interaction, we found that the complex of BRCA2 and Rad51 in breast cancer MCF-7 cells was diminished upon conditional expression of a wild-type, but not a mutated, BRC4 repeat using the tetracycline-inducible system. Cells expressing a wild-type BRC4 repeat showed hypersensitivity to gamma-irradiation, an inability to form Rad51 radiation-induced foci, and a failure of radiation-induced G(2)/M, but not G(1)/S, checkpoint control. These results strongly suggest that the interaction between BRCA2 and Rad51 mediated by BRC repeats is critical for the cellular response to DNA damage.

Temporal, spatial, and cell type-specific control of Cre-mediated DNA recombination in transgenic mice

We have developed a universal system for temporal, spatial, and cell type-specific control of gene expression in mice that (1) integrates the advantages of tetracycline-controlled gene expression and Cre-recombinase-loxP site-mediated gene inactivation, and (2) simplifies schemes of animal crosses by combination of two control elements in a single transgene. Two transgenic strains were generated in which the cell type-specific control was provided by either the retinoblastoma gene promoter or the whey acidic protein promoter. Both promoters drive the expression of the reverse tetracycline-controlled transactivator (rtTA). Placed in cis configuration to the rtTA transcription unit, the rtTA-inducible promoter directs expression of Cre recombinase. In both strains crossed with cActXstopXLacZ reporter mice, which have a loxP-stop of transcription/translation-loxP-LacZ cassette driven by chicken beta-actin promoter, Cre-loxP-mediated DNA recombination leading to LacZ expression was accurately regulated in a temporal, spatial, and cell type-specific manner. This approach can be applied to establishment of analogous mouse strains with virtually any promoter as systems to control gene regulation in a variety of cell types.

Safety and efficacy study with various doses of SS-cream in patients with premature ejaculation in a double-blind, randomized, placebo controlled clinical study

OBJECTIVES

SS-cream is a topical agent made from the extracts of natural products for treating premature ejaculation (PE). To determine the optimal clinical dosage of SS-cream on PE, we investigated the safety and efficacy of SS-cream with various doses. A double blind, randomized placebo controlled clinical study was performed.

METHODS

Fifty patients completed the study. Mean age of the patients was 37.1+/-1.O y and mean ejaculatory latency was 1.35+/-0.07 min. Sexual satisfaction rate of both the partner and patient was 16.2%. Each patient was instructed to apply the different cream (placebo, SS-cream 0.05, 0.10, 0.15, 0.20 g) on glans penis 1 h before sexual intercourse in random fashion. The ejaculatory latency was measured by stop watch and the satisfaction rate of both partner and patient was also recorded two times in the screening period and after the application of each test drugs. Clinical efficacy was considered if ejaculatory latency was prolonged more than 2 min and sexual satisfaction rate increased more than 20% than that of pretest values.

RESULTS

The mean ejaculatory latencies were significantly prolonged after using various test drugs (placebo 2.27+/-0.32, SS-cream 0.05 g 4.47+/-0.81, 0.10 g 5.34+/-0.79, 0.15 g 6.22+/-0.87, 0.20 g 11.06+/-1.17 min, respectively). Clinical efficacies evaluated by ejaculatory latency were placebo 18%, SS-cream 0.05 g 30%, 0.10 g 60%, 0.15 g 54%, 0.20 g 84%, respectively. The satisfaction rate was also significantly increased dose-dependently (placebo 26%, SS-cream 0.05 g 60%, 0.10 g 70%, 0.15 g 78%, 0.20 g 90%, respectively). A side effect such as local mild burning sensation was noted in 35/250 times (14%) and no adverse effect on sexual function and no systemic side effects were observed. From the result of logistic regression analysis on clinical efficacy, the ED50 of SS-cream was obtained as 0.10 g. SS-cream 0.20 g was effective in 84% without any serious systemic side effects.

CONCLUSION

From the above results, our conclusions are that SS-cream is effective on the treatment of PE with a few local side effects and that clinical optimal dose of SS-cream is 0.20 g.

Perinatal hypoxia-ischemia decreased neuronal but increased cerebral vascular endothelial IGFBP3 expression

In adults, insulin-like growth factor binding protein 3 (IGFBP3) is the main carrier protein for circulating insulin-like growth factors (IGFs) (IGF-I and -II). While most IGFBP3 is synthesized in the liver, it is also expressed locally by many cell types including vascular endothelial cells. The regulation of this endothelial IGFBP3 expression, especially in response to hypoxic-ischemic injury, has not been investigated in vivo. Using in situ hybridization histochemistry, we studied the cellular distribution of IGFBP3 mRNA in rat brains following hypoxic-ischemic injury at 1, 5, 24, and 72 h of recovery. In normal P7 rat brain, IGFBP3 mRNA was found in neurons within the thalamus, hippocampus, and amygdaloid. Low levels of IGFBP3 mRNA were also detected in cerebral vascular endothelial cells. After the hypoxic-ischemic injury, the levels of neuronal IGFBP3 mRNA substantially decreased within 24 h in areas that were normally supplied by the middle cerebral artery. In the meantime, there was an immediate increase in IGFBP3 expression in vascular endothelial cells throughout the affected hemisphere. This vascular IGFBP3 expression was further enhanced with the highest level at 24 h of recovery whereas neuronal IGFBP3 expression was further decreased. By 72 h of recovery, IGFBP3 was no longer expressed in vascular endothelial cells. Taken together, the activation of IGFBP3 is a likely mechanism by which vascular endothelial cells respond to hypoxic-ischemic insult. In addition, increased endothelial IGFBP3 may modulate the interaction of IGFs with IGF-I receptors at the site of injury and/or act independently on endothelial cell growth.

Activation of monocytes, T-lymphocytes and plasma inflammatory markers in angina patients

Inflammation and activation of immune cells have important roles in the pathogenesis of atherosclerosis. We analyzed the plasma levels of inflammatory markers and the degree of activation of peripheral blood monocytes and T-lymphocytes isolated from 12 unstable angina, 12 stable angina, and 12 normal subjects. In 20%-33% of patients, monocytes expressed high basal levels of IL-8, tissue factor, IL-1beta, and monocyte chemoattractant protein-1 mRNA. Furthermore, basal mRNA levels of these cytokines showed strong correlation with each other (p < 0.01 in all combination) but not with tumor necrosis factor-alpha or transforming growth factor-beta1. Plasma level of C-reactive protein was highest in the unstable angina patients (1.63+/-0.70 mg/l) and lowest in the control subjects (0.22+/-0.08 mg/l) (P = 0.03). We also observed a high correlation between C-reactive protein level and the occurrence of minor and major coronary events during 6 months of follow-up. Activation status of T-cells, assessed by the percentage of HLA-DR positive cells, was highest in the unstable angina patients (26.8+/-1.4%) compared with that in the control (14.7+/-1.2%) (P = 0.0053). Our data represent the first case showing that the circulating monocytes in angina patients are activated to a state express numerous proatherogenic cytokines. These results may help to diagnose angina patients according to the inflammatory markers and evaluate the prognosis of the disease.

Glucose and amino acid kinetic response to graded infusion of rhIGF-I in the late gestation ovine fetus

Insulin-like growth factor I (IGF-I) has anabolic effects and is thought to be important in fetal development. The present study was designed to determine the dose response of recombinant human (rh) IGF-I on ovine fetal glucose and amino acid kinetics. Chronically catheterized fetal lambs were studied at 122-127 days gestation. The kinetics of leucine, phenylalanine, and glucose were measured before and during the infusion of rhIGF-I. rhIGF-I was infused into the fetal inferior vena cava at low, medium, or high rates (9.9, 20.1, or 40.2 nmol/h, respectively). A stepwise increase in serum IGF-I was achieved (164 +/- 3, 222 +/- 7, and 275 +/- 5 ng/ml). Insulin concentrations were decreased at the medium and high rhIGF doses. The rate of appearance (Ra) of leucine and phenylalanine and leucine oxidation decreased. Phenylalanine appearance from protein breakdown was decreased, with a maximal suppression of 30% observed at the highest rate of infusion. Glucose Ra was increased at the medium and high doses; other aspects of glucose metabolism were unchanged. The change in both glucose Ra and suppression of proteolysis was significantly correlated to the rhIGF-I infusion rate. It is concluded that rhIGF-I exerts dose-related effects in the ovine fetus, increasing fetoplacental glucose turnover and causing significant suppression of both proteolysis and amino acid oxidation.

Lymphatic cyst of the colon: a case report

A rare case of a lymphatic cyst of the ascending colon is reported. The lobulated and fluctuant lesion, located in the hepatic flexure, was diagnosed by barium enema and colonoscopy, incidentally. Surgical treatment with segmental resection of the ascending colon was done because of the risk of obstruction and the question of an underlying malignancy. The clinical features, appropriate treatment, preoperative diagnosis and histopathology are discussed. We emphasize that lymphatic cysts are very rare and are difficult to identify by radiology or colonoscopy before surgery. They must be included in the differential diagnosis of submucosal tumors such as lipomas, leiomyomas and hemangiomas.

Hec1p, an evolutionarily conserved coiled-coil protein, modulates chromosome segregation through interaction with SMC proteins

hsHec1p, a Homo sapiens coiled-coil-enriched protein, plays an important role in M-phase progression in mammalian cells. A Saccharomyces cerevisiae protein, identical to Tid3p/Ndc80p and here designated scHec1p, has similarities in structure and biological function to hsHec1p. Budding yeast cells deleted in the scHEC1/NDC80 allele are not viable, but this lethal phenotype can be rescued by hsHEC1 under control of the endogenous scHEC1 promoter. At the nonpermissive temperature, significant mitotic delay, chromosomal missegregation, and decreased viability were observed in yeast cells with temperature-sensitive (ts) alleles of hsHEC1. In the hshec1-113 ts mutant, we found a single-point mutation changing Trp395 to a stop codon, which resulted in the expression of a C-terminally truncated 45-kDa protein. The binding of this mutated protein, hshec1-113p, to five identified hsHec1p-associated proteins was unchanged, while its binding to human SMC1 protein and yeast Smc1p was ts. Hec1p also interacts with Smc2p, and the binding of the mutated hshec1-113p to Smc2p was not ts. Overexpression of either hsHEC1 or scHEC1 suppressed the lethal phenotype of smc1-2 and smc2-6 at nonpermissive temperatures, suggesting that the interactions between Hec1p and Smc1p and -2p are biologically significant. These results suggest that Hec1 proteins play a critical role in modulating chromosomal segregation, in part, through their interactions with SMC proteins.

Association of BRCA1 with the hRad50-hMre11-p95 complex and the DNA damage response

BRCA1 encodes a tumor suppressor that is mutated in familial breast and ovarian cancers. Here, it is shown that BRCA1 interacts in vitro and in vivo with hRad50, which forms a complex with hMre11 and p95/nibrin. Upon irradiation, BRCA1 was detected in discrete foci in the nucleus, which colocalize with hRad50. Formation of irradiation-induced foci positive for BRCA1, hRad50, hMre11, or p95 was dramatically reduced in HCC/1937 breast cancer cells carrying a homozygous mutation in BRCA1 but was restored by transfection of wild-type BRCA1. Ectopic expression of wild-type, but not mutated, BRCA1 in these cells rendered them less sensitive to the DNA damage agent, methyl methanesulfonate. These data suggest that BRCA1 is important for the cellular responses to DNA damage that are mediated by the hRad50-hMre11-p95 complex.

Hypoxia-ischemia-induced apoptotic cell death correlates with IGF-I mRNA decrease in neonatal rat brain

Hypoxia-ischemia induces apoptotic and necrotic cell death, which results partially from persistent alterations in cellular energy homeostasis. Insulin-like growth factor I (IGF-I) is an anabolic pleiotrophic factor required by developing neurons for their optimal proliferation, differentiation, and survival. To determine how cell death and changes in IGF-I gene expression relate to the extent of hypoxia-ischemia, we evaluated the time course of apoptosis in a neonatal hypoxia-ischemia model in relation to the cellular distribution of IGF-I and IGFBP5 mRNA. Severe hypoxia-ischemia results in an immediate decrease in neuronal IGF-I and IGFBP5 mRNA. The decrease in neuronal IGF-I mRNA was concurrent with an increase in the number of apoptotic cells. It is conceivable that the immediate decrease in IGF-I gene expression may contribute to the impending neuronal death and selective vulnerability of myelinogenesis during the perinatal period.

Characterization of a promoter for the human glial cell line-derived neurotrophic factor gene

To address the regulation of glial cell line-derived neurotrophic factor (GDNF) gene expression, we have isolated 5' extended cDNAs, cloned the human GDNF gene, and characterized the promoter. GDNF-encoding 5' extended cDNAs containing a novel exon were isolated via reverse transcription-polymerase chain reaction (RT-PCR) of mRNA from human fetal kidney and adult skeletal muscle. The GDNF gene was isolated from a human genomic library in a P1 bacteriophage vector. Analysis of the 5' flanking sequence revealed a promoter that lacks a CCAAT-box motif and is GC rich. Consensus binding sites for a variety of transcription factors have been identified in the promoter. Promoter/reporter plasmids have been constructed by fusion of the promoter and a portion of exon I to a luciferase gene. The promoter/reporter construct and a number of promoter deletions were transiently transfected into two human cell lines known to express GDNF. Multiple enhancer and silencer regions were revealed as well as a minimal promoter sufficient for basal transcription. Finally, a RT-PCR assay, specific for transcripts originating from this GDNF promoter, was developed and used to show that this promoter is active in vivo. The results suggest GDNF is regulated in a complex manner.

Crystallization and preliminary X-ray diffraction studies of piratoxin III, a D-49 phospholipase A2 from the venom of Bothrops pirajai

Piratoxin III (PrTX-III) is a phospholipase A2 (PLA2, E.C. 3.1.1.4, phosphatide sn-2 acylhydrolase) isolated from Bothrops pirajai. Crystals of PrTX-III were obtained using the vapour-diffusion technique and X-ray diffraction data have been collected to 2.7 A resolution. The enzyme was crystallized in the space group C2 with unit-cell parameters a = 60.88, b = 100.75, c = 48.19 A, beta = 123. 89 degrees. A molecular-replacement solution of the structure has been found using bothropstoxin I from the venom of B. jararacussu as a search model.

Binding of CtIP to the BRCT repeats of BRCA1 involved in the transcription regulation of p21 is disrupted upon DNA damage

Mutations in BRCA1 are responsible for nearly all of the hereditary ovarian and breast cancers, and about half of those in breast cancer-only kindreds. The ability of BRCA1 to transactivate the p21 promoter can be inactivated by mutation of the conserved BRCA1 C-terminal (BRCT) repeats. To explore the mechanisms of this BRCA1 function, the BRCT repeats were used as bait in a yeast two-hybrid screen. A known protein, CtIP, a co-repressor with CtBP, was found. CtIP interacts specifically with the BRCT repeats of BRCA1, both in vitro and in vivo, and tumor-derived mutations in this region abolished these interactions. The association of BRCA1 with CtIP was also abrogated in cells treated with DNA-damaging agents including UV, gamma-irradiation, and adriamycin, a response correlated with BRCA1 phosphorylation. The transactivation of the p21 promoter by BRCA1 was diminished by expression of exogenous CtIP and CtBP. These results suggest that the binding of the BRCT repeats of BRCA1 to CtIP/CtBP is critical in mediating transcriptional regulation of p21 in response to DNA damage.

Thyroid hormone, T3-dependent phosphorylation and translocation of Trip230 from the Golgi complex to the nucleus

Trip230 is a novel coactivator of the thyroid hormone receptor that is negatively regulated by the retinoblastoma tumor-suppressor protein. In an examination of its subcellular distribution, Trip230 localized predominantly to the vicinity of the Golgi instead of the nucleus, as other nuclear hormone receptor coactivators. Using a series of deletion mutants, a critical region identified for Golgi area targeting coincided with a previously defined thyroid hormone receptor-binding domain of Trip230. During cell cycle progression, the expression level of Trip230 is constant and a significant portion is imported into the nucleus at S phase. Within an hour of treating cells with T3, Trip230 immunofluorescence transiently colocalized with TR in prominent subnuclear structures. T3-dependent nuclear import of Trip230 does not require new protein synthesis. Coincident with T3 treatment and nuclear import, newly phosphorylated residue(s) appeared in Trip230, suggesting that phosphorylation may be involved in its nuclear import. These findings provided a novel mechanism for the regulation of nuclear hormone transcription factors by hormone-responsive phosphorylation and nuclear import of cytoplasmically located coactivators.

The expression of type I growth factor receptors in the squamous neoplastic changes of uterine cervix

AIM

The type I family of growth factor receptors includes ErbB1, ErbB2, ErbB3, and ErbB4 which are frequently overexpressed in various human cancer cells. In this study, we systematically investigated the frequency and distribution of these four receptors in relation to neoplastic changes and tumor behaviors in the uterine cervix.

MATERIALS

A total 84 of cases including 12 cases of normal cervical tissues, 6 cases of low grade squamous intraepithelial lesion, 10 cases of high grade squamous intraepithelial lesion, and 56 cases of squamous cells carcinoma were examined.

RESULTS

Our results show significant difference with increasing grades of dysplasia in terms of these four receptor expressions. No association was found between these four receptors and cell keratinization/differentiation of squamous cell carcinoma of the cervix. Of the four receptors studied, only the expression of erbB2/neu gene was significantly associated with lymph nodal metastasis. Moreover, we find that the coexpression of ErbB1 and ErbB4 was significant in cervical carcinoma.

CONCLUSIONS

The coexpression of ErbB1 and ErbB4 in cervical carcinoma suggests that they may be involved in receptor heterodimerization leading to the activation of signaling pathway in the cervical carcinoma.

RB-mediated suppression of spontaneous multiple neuroendocrine neoplasia and lung metastases in Rb+/- mice

Alterations in pathways mediated by retinoblastoma susceptibility gene (RB) product are among the most common in human cancer. Mice with a single copy of the Rb gene are shown to develop a syndrome of multiple neuroendocrine neoplasia. The earliest Rb-deficient atypical cells were identified in the intermediate and anterior lobes of the pituitary, the thyroid and parathyroid glands, and the adrenal medulla within the first 3 months of postnatal development. These cells form gross tumors with various degrees of malignancy by postnatal day 350. By age of 380 days, 84% of Rb+/- mice exhibited lung metastases from C-cell thyroid carcinomas. Expression of a human RB transgene in the Rb+/- mice suppressed carcinogenesis in all tissues studied. Of particular clinical relevance, the frequency of lung metastases also was reduced to 12% in Rb+/- mice by repeated i.v. administration of lipid-entrapped, polycation-condensed RB complementary DNA. Thus, in spite of long latency periods during which secondary alterations can accumulate, the initial loss of Rb function remains essential for tumor progression in multiple types of neuroendocrine cells. Restoration of RB function in humans may prove an effective general approach to the treatment of RB-deficient disseminated tumors.

A male newborn with colonic atresia and total colonic aganglionosis

A case of colonic atresia (CA) and aganglionosis is presented, which is probably the tenth in the English literature. The boy presented on day 3 of life with delayed passage of meconium, milk intolerance, and progressive abdominal distension. A barium enema study was complicated by barium peritonitis. Emergency peritoneal lavage was done and the intestinal obstruction was relieved by a proximal defunctioning ileostomy; type III CA (Grosfeld classification) was identified. The proximal atretic end was the blind-ending caecum and the distal atretic end commenced in the splenic area as a microcolon extending to the pelvis and replacing the normal colon. Total colonic aganglionosis (TCA) was confirmed by biopsies. This is the first case in the literature of TCA with CA documented before any attempts at colonic resection and anastomosis were made. This association highlights the recommendation for biopsy of the micro-colon and rectum when Type III CA (Grosfeld classification) is encountered in a newborn. The infant underwent a cholecystectomy and Duhamel-Martin operation at 14 months that was complicated by abdominal wound dehiscence; the ileostomy was closed at 22 months of age.

Intracerebral hemorrhage caused by cerebral amyloid angiopathy: a case report

Cerebral amyloid angiopathy (CAA) accounts for approximately 10% of spontaneous intracerebral hemorrhages (ICH), and typically occurs in the cortex and subcortical white matter. It is characterized by the deposition of amyloid fibrils in the leptomeningeal, cortical and subcortical arteries. Pathologically, amyloid is stained pink with Congo red and shows yellow-green birefringence when viewed under polarized light. Although there have been many reports of CAA in the literature, it has rarely been described in Taiwan. This is the report of a case of a 75-year-old man with ICH caused by CAA. The postoperative course was uneventful. The incidence of this disease increases with age. The authors, therefore, suggest conducting a brain biopsy and special stain for CAA in each operative case of spontaneous ICH, especially in the elderly.

Early expression of a malignant phenotype of familial hypertrophic cardiomyopathy associated with a Gly716Arg myosin heavy chain mutation in a Korean family

The clinical course and prognosis of familial hypertrophic cardiomyopathy (HCM) are different according to the type of mutation in the genes for sarcomere proteins. It has been disputed that a mutation, which occurs at a functionally important region in the sarcomere proteins, may increase the penetrance and expressivity of the disease. We searched for a causative mutation in an HCM family, which is characterized by early expression of clinical phenotype, high incidence of sudden death at young ages, and progressive heart failure in adults. Among the 32 family members in 4 generations, 13 were affected; 4 died suddenly before age 16, 2 children have already had full expression of the cardiac hypertrophy, and other adults have either progressive heart failure or poor left ventricular systolic functions. PCR-SSCP (polymerase chain reaction-single strand confirmation polymorphism) analysis of genomic DNAs isolated from peripheral blood leukocytes of the family members identified a Gly716Arg mutation in the cardiac beta-myosin heavy chain gene, which was cosegregated with the clinical phenotype. The mutation is localized near a functionally important site of the myosin heavy chain, the 2 active thiols, which contribute to the adenosine triphosphatase activity of myosin S1. This family provides further evidence that the mutation, which occurs at a functionally important site of the myosin heavy chain, is associated with the high penetrance and early expression of HCM.

Expression of heat shock protein 70 blocks thymic differentiation of T cells in transgenic mice

Heat shock protein 70 (HSP70) is involved not only in protein folding, but also in processes of differentiation and cell-cycle progression. Recently, HSP70 has been implicated in mediation of functions of some immunosuppressive agents. To study the role of HSP70 in differentiation of haematopoietic cells, we generated transgenic mice using the human inducible hsp70 gene fused to the mouse H-2K promoter. These mice develop a T-cell deficiency that is characterized by thymic hypoplasia and a significant reduction in peripheral T cells. The total number of thymocytes is about 100-fold less than that in normal mice. The majority of the thymocytes are immature T cells that express neither CD4 nor CD8 molecules, indicating that T cells are affected at an early stage of thymic differentiation. Expression of the transgenic HSP70 was detected both in bone marrow cells and in thymocytes. Furthermore, injection of normal bone marrow cells into the T-cell deficient mice led to the generation of mature T cells indicating that the T-cell deficiency was caused by the action of HSP70 in T cells. The blockage of differentiation occurred only in T cells, both alphabeta- and gammadelta-T-cell receptor (TCR)-bearing cells, but not in B cells, granulocytes, and monocytes. The observations suggest that HSP70 may inhibit a cellular process that is essential for the differentiation of early stage T cells. Further experiments using this model system will widen our understanding of HSP70 and its function on a molecular level.

Spontaneous breakage of malleable penile prosthesis

The reported complications of malleable penile prosthesis include infection, erosion and chronic pain. We report the first two cases of bilateral breakage of malleable penile prosthesis.

Effect of rhIGF-I infusion on whole fetal and fetal skeletal muscle protein metabolism in sheep

Insulin-like growth factor I (IGF-I) has been shown to have significant anabolic effects in the regulation of fetal protein metabolism. To investigate the tissue-specific effects of IGF-I on fetal skeletal muscle metabolism, we infused recombinant human (rh) IGF-I directly into the hindlimb of nine chronically catheterized, late-gestation fetal sheep. Substrate balance and amino acid kinetics were measured across the hindlimb and were compared with the effects at the whole body level before and during a 3-h infusion of rhIGF-I into the external iliac artery at 150 microgram/h. Infusion of rhIGF-I resulted in increases in IGF-I concentrations by 2- to 5. 75-fold in the ipsilateral iliac vein and by nearly 3-fold in the abdominal aorta. In the study limb, IGF-I had no effect on protein synthesis (phenylalanine rate of disposal 0.88 +/- 0.13 before vs. 0. 73 +/- 0.19 micromol/min during IGF-I) or breakdown (phenylalanine rate of appearance 0.67 +/- 0.13 before vs. 0.60 +/- 0.17 micromol/min during IGF-I) and did not alter net phenylalanine balance. IGF-I also did not affect hindlimb oxygen or glucose uptake. In contrast, at the whole body level, the rate of appearance of leucine, indicative of fetal protein breakdown, decreased during IGF-I infusion (rate of appearance of leucine 41.1 +/- 3.3 to 37.6 +/- 2.7 micromol/min) as did fetal leucine oxidation (8.4 +/- 0.8 to 6.8 +/- 0.6 micromol/min). There was no change in the umbilical uptake of leucine, and although not statistically significant, fetal leucine accretion increased 2.4-fold. These results provide further evidence that IGF-I promotes fetal protein accretion; however, its site of action is in tissues other than skeletal muscle.

Functional domains of the BRCA1 and BRCA2 proteins

The BRCA1 and BRCA2 genes encode large unrelated proteins that presumably function as tumor suppressors in normal epithelial cells of the breast. However, the primary amino acid sequences of these proteins provide few insights into the mechanisms by which BRCA1 and BRCA2 inhibit tumor development. Nevertheless, recent studies have uncovered many similarities in the biological properties of BRCA1 and BRCA2, raising the prospect that these proteins may function in a common pathway of tumor suppression and that inactivation of either gene may represent an equivalent step in the development of breast cancer. Several lines of evidence now suggest a role for BRCA1 and BRCA2 in the cellular response to DNA damage, possibly by virtue of their relationship with proteins required for the recombinational repair of double-strand DNA breaks. Accordingly, the loss of BRCA1 or BRCA2 function might accelerate tumor development by allowing cells to accumulate DNA lesions that are potentially oncogenic.

Haemophilus influenzae type b infections in Hong Kong

A 5-year territory-wide retrospective survey of invasive Haemophilus influenzae type b (Hib) diseases in Hong Kong established that the annual incidence for children <5 years old was 2.7 per 100000 [95% confidence interval (CI), 2.0 to 3.5]. However, the corresponding annual incidence in Vietnamese refugees in Hong Kong was 42.7 per 100000 (95% CI 17.2 to 87.9), giving a relative risk of 18.5 (95% CI 8.3 to 41.0). The nasopharyngeal carriage rate of Hib was zero in 621 healthy Chinese children and 1.3% (95% CI 0.04 to 2.63%) in 300 healthy Vietnamese refugees 2 months to 5 years old in Hong Kong. The corresponding carriage rate of nontypable H. influenzae was 5.8% (95% CI 1.4 to 7.6%) in Chinese and 65.4% (95% CI 58.9 to 69.8) in Vietnamese. In a larger study of 1812 healthy Chinese children between 6 months and 5 years of age investigated by throat swabs, again no Hib was isolated but 141 children (7.8%) were found to be carriers of nontype b H. influenzae. In a study of 596 healthy Chinese children and adults, 25% had the protective level of anti-Hib antibody of >0.15 microg/ml by 1 year and 90% had reached >0.15 microg/ml by 6 years of age. There was some evidence that these "natural" antibodies against Hib in Hong Kong Chinese were cross-reacting antibodies against antigens on other encapsulated bacteria.

Apoptosis in nasopharyngeal carcinoma as related to histopathological characteristics and clinical stage

AIMS

We investigated the significance of apoptosis, using the terminal deoxynucleotidyl transferase mediated dUTP-digoxigenin nick end-labelling method, in nasopharyngeal carcinoma biopsy samples.

METHODS AND RESULTS

The apoptotic index (AI) in 50 nasopharyngeal carcinomas was compared with various histopathological features and clinical stage. Also, the AI was correlated with p53, bcl-2 and Ki67 expression by immunohistochemistry. In histopathological studies, the AI was significantly higher in mixed cellular type (MC) than in keratizing squamous cell type (KS) and spindle cell type (SC) (P < 0.001) which worsens prognosis. In tumour stage analyses, AI was higher in early stage (stage 2 and 3) than in high stage (stage 4). In addition, there was a significant correlation between the AI and p53 expression (P < 0.001) but not with proliferative activity (P = 0.15). In NPC containing p53 protein positive tumour cells, there was a significantly higher apoptotic rate.

CONCLUSIONS

These findings indicate that apoptosis is related to type and stage of nasopharyngeal carcinoma. They also confirm the role of p53 in regulating tumour apoptosis.

Genistein-induced G2/M arrest is associated with the inhibition of cyclin B1 and the induction of p21 in human breast carcinoma cells

Genistein is an isoflavone known to inhibit both tyrosine protein kinase and DNA topoisomerase II. We have investigated the mechanism of genistein-induced growth inhibition in MCF-7 and MDA-MB-231 breast carcinoma cell lines. DNA flow cytometric analysis indicated that genistein induced a G2/M arrest in both cell lines. Therefore, we examined the effect of genistein on cell cycle-related proteins. Western blot analysis using whole cell lysates from MCF-7 and MDA-MB-231 treated with genistein demonstrated that genistein treatment did not change the steady-state level of cdks, cyclin A, D-type cyclins and cyclin E protein, but inhibited expression of cyclin B1 protein in a time-dependent manner. The reduction in the protein level of cyclin B1 correlated with a decrease in the level of cyclin B1 mRNA. Genistein induced expression of p21, and the increased levels of p21 were associated with increased binding of p21 with cdc2 and cdk2. These observations suggest that genistein induces a G2/M arrest in human breast cancer cells, the mechanism of which is in part due to inhibition of kinase activities of cdc2 and cdk2, and decrease in cyclin B1 expression.

Perturbation of TSG101 protein affects cell cycle progression

tsg101 was recently identified as a tumor susceptibility gene by functional inactivation of allelic loci in mouse 3T3 fibroblasts. Although previous studies suggested that homozygous intragenic deletion of TSG101 is rare in breast cancer cells and specimens, the neoplastic phenotype caused by tsg101 inactivation implicated that tsg101 may play a significant role in cell growth control. Here, we characterize mouse polyclonal and monoclonal antibodies that specifically recognize the TSG101 protein (molecular mass, 46 kDa) in whole-cell lysates by straight Western blot analysis. By indirect immunofluorescence staining, TSG101 was found to be localized in the cytoplasm throughout the entire cell cycle. However, the nuclear staining increases from G1 to S phase and becomes dominant in late S phase. TSG101 is mainly distributed surrounding the chromosomes during M phase. The expression level of TSG101 is not cell cycle dependent. It is possible that the relocalization of TSG101 from the cytoplasm into the nucleus may be relevant to its function. Microinjection of both polyclonal and monoclonal antibodies specific to TSG101 into cells during G1 or S phase results in cell cycle arrest. Furthermore, overexpression of TSG101 leads to cell death, suggesting that the appropriate amount of TSG101 is critical for cell cycle progression. Taken together, these results suggest that neoplastic transformation caused by TSG101 deficiency may result from bypassing of the cell cycle checkpoints.

Treatment of intertrochanteric fracture with the Gamma AP locking nail or by a compression hip screw--a randomised prospective trial

The Gamma AP (Asia-Pacific) locking nail (GAPN) is a modification of the standard Gamma locking nail made especially for use in Oriental patients. We made a randomised prospective comparison of the compression hip screw (CHS) and the Gamma AP locking nail for the internal fixation of 60 intertrochanteric fractures of the hip in elderly patients by comparing perioperative details and analysing the radiographic and clinical results. The operation time for the GAPN group was shorter than for the CHS group and the intraoperative blood loss was lower. The Gamma AP nail enabled earlier mobilisation. We found no significant difference in the time to union and the length of sliding of the lag screw between the two groups. The decrease in the neck shaft angle in the Gamma nail group was significantly smaller than in the CHS patients. There were no significant mechanical complications, such as fracture of the femoral shaft or failure of fixation in the Gamma nail group. On the basis of our observations we conclude that the Gamma AP locking nail is more efficient than the CHS in the treatment of intertrochanteric fractures in geriatric patients.