Amyloid precursor protein, heat-shock proteins, and Bcl-2 form a complex in mitochondria and modulate mitochondria function and apoptosis in N2a cells

Neurons that degenerate in the brains of persons with Alzheimer's disease accumulate mitochondrial amyloid precursor protein (APP), which is thought to negatively affect mitochondrial function and cellular homeostasis. Because proteins that enter mitochondria require assistance from chaperone proteins, we hypothesized that heat-shock proteins (HSPs) help accumulate APP in mitochondria. We found that APP overexpression in N2a cells (APP cells) did not elicit mitochondrial dysfunction. Because cerebral hypoperfusion-associated energy deficiency is an important etiology for Alzheimer's disease, we also challenged the cells with serum starvation. APP/HSP/Bcl-2 complexes formed within the mitochondria of serum-starved APP cells, but not control cells. Mitochondria containing APP/HSP/Bcl-2 complexes induced apoptosis. We hypothesize that APP/HSP/Bcl-2 complexes diminish the functional capacities of HSPs and Bcl-2, which leads to mitochondrial injury and apoptosis.

Intermittent vaginal injections of gonadotrophins for ovarian stimulation in IVF treatment

Intermittent vaginal administration of recombinant human FSH (rhFSH), for ovarian stimulation in IVF employing the concept of uterine first-pass effect and mesotherapy, was investigated. Injection of rhFSH (437 IU, counted as six ampoules) was carried out every 3 days into the vaginal mucosa of 66 participants receiving IVF treatment between November 2004 and August 2006. The primary outcomes were number of mature oocytes, number of good grade embryos, and term live birth rate (>/=37 weeks gestation). On average, 2.94 days of injection and 16.35 ampoules of rhFSH were required to achieve proper follicular growth. Although fewer mature oocytes (5.27 +/- 3.69) were retrieved, the number of good grade embryos (3.05 +/- 1.95), number of embryos transferred (2.66 +/- 1.70), pregnancy rate per cycle started [37.9%; 95% confidence interval (CI), 27.1-49.9], implantation rate (25.5%; 95% CI, 18.0-33.0), and term live birth rate (31.8 %; 95% CI, 21.8-43.8) were comparable with conventional IVF treatments in this clinic.

Ulinastatin alone does not reduce caspase 3-mediated apoptosis in protease-positive Aeromonas hydrophilia-induced sepsis

BACKGROUND/PURPOSE

To evaluate the effect of ulinastatin, a protease inhibitor, on survival and apoptosis in protease-positive Aeromonas hydrophilia (PPAH)-induced sepsis.

METHODS

Thirty mice were randomly allocated to receive intraperitoneal injection of either phosphate buffered saline (PBS) (control mice, n = 10) or PPAH (PPAH mice, n = 20). After 30 minutes, control mice received an additional intraperitoneal PBS injection, 10 PPAH mice received intraperitoneal PBS injection (non-treated PPAH mice), and the remaining 10 PPAH mice received an intraperitoneal injection of ulinastatin (ulinastatin-treated PPAH mice).

RESULTS

Survival at 24 hours was 100% in control mice, and 35% (p < 0.05) in PPAH mice; the survival rate in non-treated and ulinastatin-treated PPAH mice were 30% and 40% (p > 0.05), respectively. The thymus weight (mg) decreased significantly in PPAH mice (51.1 +/- 14.9) compared to control mice (69.7 +/- 14.4; p < 0.001); there was no difference between ulinastatin-treated (52 +/- 13.9; p > 0.05) and non-treated PPAH mice (50.4 +/- 16). The thymus gland cell count reduced significantly in PPAH mice (8.1 +/- 4.7 x 10(7)) compared to control mice (12.8 +/- 6.6 x 10(7); p < 0.01), and immunofluorescence analysis demonstrated that the reduced cells were mostly CD4+ CD8+, in contrast to the increase in CD4+ CD8- cells. There was no difference in cell count between ulinastatin-treated (8.7 +/- 4.9 x 10(7)) and non-treated PPAH mice (7.4 +/- 4.6 x 10(7); p > 0.05). Caspase 3-mediated apoptosis was not detectable in control mice in contrast to the pronounced manifestation in PPAH mice.

CONCLUSION

PPAH-induced sepsis has a high mortality that is related to lymphocyte apoptosis. Ulinastatin alone does not significantly reduce caspase 3-mediated lymphocyte apoptosis.

Changes of dopamine content and cell proliferation by dexamethsone via pituitary adenylate cyclase-activating polypeptide in PC12 cell

Pituitary adenylate cyclase-activating polypeptide (PACAP) is an endogenous neuropeptide observed in adrenal gland and sympathetic ganglia to regulate catecholamine synthesis and release. Both PACAP and glucocorticoid showed the activity to elevate catecholamine level through the stimulation of biosynthesis. However, the relationship of glucocorticoid and PACAP for this action is still unclear. Thus, alterations of gene expression, dopamine (DA) content, and cell proliferation in rat pheochromocytoma PC12 cells are employed as indicators to clarify this relationship in the present study. From the analysis of RT-PCR, the mRNA level of PACAP was observed to be raised by dexamethasone (DEX) and this action was blocked in cells treated with RU486 (mifepristone), a glucocorticoid receptor (GR) antagonist, or actinomycin D, a transcriptional inhibitor. An increase of DA content by HPLC analysis and/or cell proliferation identified by MTT assay by DEX was also observed which could be inhibited by PACAP (6-38) at concentration sufficient to block PACAP type 1 (PAC1) receptor. These results suggest that PACAP is involved in DEX-induced DA biosynthesis and cell proliferation in PC12 cells.

Alterations of M2-muscarinic receptor protein and mRNA expression in the urothelium and muscle layer of the streptozotocin-induced diabetic rat urinary bladder

Diabetes associated alterations of M2-muscarinic receptors (M2-mAChR) in the urothelium and muscle layer of the urinary bladder were studied using streptozotocin (STZ)-induced diabetic rats. Male Wistar rats were divided into two groups; group I: normal control rats; group II: STZ-induced diabetic rats, 2 weeks after induction. The bladder was divided into urothelium and muscle layer by microdissection. Tissue M2-mAChR protein levels were measured by Western blotting. Expression of the mRNA that encoded M2-mAChR was estimated using the method of reverse transcription combined with polymerase chain reaction (RT-PCR). M2-mAChR protein and mRNA expressions were found in both the urothelium and muscle layer of the rat urinary bladder. In control rats, the M2-mAChR protein expression ratio in the urothelium and muscle layer was 1:1.66; that for mRNA was 1:0.97. Two weeks after induction of diabetes, the M2-mAChR mRNA expression in the urothelium and muscle layer were significantly increased by 44.4% (P<0.01, n=8) and 28.6% (P<0.01, n=8), respectively. Correspondently, the bladder M2-mAChR protein levels were significantly increased by 33.3% (P<0.001, n=8) in the urothelium and 25.3% (P<0.01, n=8) in the muscle layer of the diabetic rats. In conclusion, M2-mAChR mRNA and protein are expressed in both the urothelium and muscle layer of the rat urinary bladder. STZ-induced diabetes increases mRNA and protein expression of the M2-mAChR in the urothelium as well as the muscle layer.

Conception using vaginal administration of gonadotrophins in IVF: a case report

A method has been developed of injecting gonadotrophins vaginally every 3-4 days, to reduce both the dose and frequency of injections. A couple with primary infertility for 5 years with a previous failed IVF cycle was recruited. A total dose of 1200 IU gonadotrophins was administered in three injections. Ten mature oocytes were recovered and six fertilized two-pronuclear stage zygotes resulted. The patient conceived after replacement of three good quality embryos.

Ovarian pregnancy resulting from cornual fistulae in a woman who had undergone bilateral salpingectomy

OBJECTIVE

To report a case of ovarian pregnancy following in vitro fertilization-embryo transfer (IVF-ET) treatment for which the cornual fistulae was the most probable explanation of the cause.

DESIGN

Case report.

SETTING

University department and assisted reproduction unit.

PATIENT(S)

A 29-year-old woman with primary infertility.

INTERVENTION(S)

Hydrosalpinx of the bilateral fallopian tubes has been noted in patients who have decreased pregnancy rates in the IVF-ET treatment cycles. Salpingectomy before IVF cycles has been suggested to increase the pregnancy rate. We report a patient who presented with bilateral hydrosalpinx for whom bilateral salpingectomy was performed before IVF treatment.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy.

RESULT(S)

The treatment cycle resulted in a primary ovarian pregnancy and required laparoscopic operation. A cornual fistulae was found that have might led to ectopic implantation of the embryos.

CONCLUSION(S)

Ovarian pregnancy may be an unexpected complication of those receiving bilateral salpingectomy before IVF treatment. The presence of cornual fistulae after salpingectomy was probably the cause of the ectopic pregnancy.

Expression of Tie-2 and angiopoietin-1 and -2 in early phase of ulcer healing

BACKGROUND

Angiogenesis is an important process in tissue development and wound healing. The Tie-2 receptor tyrosine kinases and ligands, angiopoietin (Ang)-1 and -2 have been postulated to play key roles in vascular development. The purpose of this study was to evaluate the expression of Tie-2 and Ang-1 and -2 in an acetic acid-induced gastric ulcer healing process in rats.

METHODS

Gastric specimens were obtained at 0 (control), 1, 3, 5, 7, and 14 days after ulcer induction for reverse transcription polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical analysis.

RESULTS

Expression of Tie-2 and Ang-1 and -2 mRNAs was detected in normal gastric tissue and ulcerative tissues by RT-PCR. Western blot analysis revealed that Tie-2 expression reached a maximum on the third to fifth days. Expression of Ang-1 and -2 peaked on the first day. Ang-1 expression gradually became weaker in 2 weeks, whereas Ang-2 expression returned to normal in a few days. Immunohistochemically, Tie-2 was expressed constitutively in the endothelial cells of pre-existing vessels of the gastric wall, and Tie-2 expression was increased in the new capillaries of the ulcer base.

CONCLUSIONS

These findings suggest that Tie-2 and Ang-1 and -2 play an important role in angiogenesis in the early phase of ulcer healing.

Lamivudine does not increase the efficacy of interferon in the treatment of mutant type chronic viral heaptitis B

AIM: To study the role of lamivudine in improving the efficiency of interferon for the treatment of mutant type chronic hepatitis B.

METHODS: Fifteen patients with mutant type chronic hepatitis B were prospectively studied. All patients had liver histology and serology to prove the diagnosis of chronic hepatitis B. Each patient received 4.5 millionunits of interferon alpha-2a thrice weekly and 100 mg of oral lamivudine daily for 24 wk. Patients were observed and tested for blood chemistry every week for the initial 4 wk and every 2 wk thereafter during the treatment until 24 wk. After the end of treatment, patients were followed up at 4-week intervals for an additional 6 mo. Serum HBV DNA levels were tested using the liquid phase molecular hybridization assay. Those with non-detectable HBV DNA were also tested using the real-time polymerase chain reaction. One patient, who did not finish treatment due to depression, was excluded.

RESULTS: At the end of treatment, 7 (50%) patients had serum ALT levels within normal limits; 12 (86%) patients had serum HBV DNA levels < 5 pg/mL using the liquid phase molecular hybridization assay, but only 8 (67%) were < 20 copies/dL using the real-time polymerase chain reaction. Six months after treatment, only two (14%) patients had a sustained complete response to the combination therapy with serum ALT level < 35 iu/L and undetectable serum HBV DNA levels.

CONCLUSION: These pilot data showed that lamivudine did not increase the efficacy of interferon in the treatment of mutant type chronic hepatitis B. The liquid phase molecular hybridization assay was not sensitive enough to detect the low HBV DNA levels during combined interferon and lamivudine therapy.

Increase of beta-endorphin biosynthesis in the adrenal gland of streptozotocin-induced diabetic rats

Opioid plays an important role in the regulation of glucose homeostasis in diabetic rats lacking insulin. The present study investigated the changes of beta-endorphin biosynthesis in the adrenal medulla of streptozotocin-induced diabetic rats (STZ-diabetic rats) by determination of the gene expression of pro-opiomelanocortin (POMC) and the amount of beta-endorphin. Expression of the distinct mRNA that encodes proteins of POMC was studied using reverse transcription combined with polymerase chain reaction (RT-PCR). Results of RT-PCR demonstrated that the mRNA level of POMC in the adrenal gland markedly increased in STZ-diabetic rats as compared with that in normal rats. The content of beta-endorphin-like immunoreactivity (BER) in the adrenal medulla, determined by enzyme-linked immunosorbent assay, was actually higher in diabetic rats with insulin deficiency. Normalization of the plasma glucose concentration in STZ-diabetic rats with exogenous insulin or phlorizin, an inhibitor of the renal tubular glucose transport, reversed the mRNA level of POMC in the adrenal gland after 4 days of treatment. A similar decrease of BER amount also observed in the adrenal medulla of STZ-diabetic rats received the same treatment with exogenous insulin or phlorizin. Therefore, correction of hyperglycemia in STZ-diabetic rats could reverse the higher gene expression of POMC in the adrenal gland. These results suggest that hyperglycemia is responsible for the increase of POMC gene expression to enhance beta-endorphin biosynthesis in the adrenal gland of STZ-diabetic rats.

Choroidal infarction, anterior ischemic optic neuropathy, and central retinal artery occlusion from polyarteritis nodosa

PURPOSE

Ocular ischemia from polyarteritis nodosa (PAN) is rare. The authors present a case of multifocal ocular infarction from PAN.

METHODS AND RESULTS

A 70-year-old woman developed hand and foot numbness followed by intermittent blurred vision and binocular horizontal diplopia. Two weeks later, she suddenly lost vision in the right eye from a central retinal artery occlusion and then developed a left anterior ischemic optic neuropathy and bilateral triangular choroidal abnormalities consistent with infarction. Her erythrocyte sedimentation rate and C-reactive protein were elevated. Although giant cell arteritis was suspected, a multiple mononeuropathy was demonstrated by electromyogram and nerve conduction velocity studies. Biopsy specimens from her sural nerve and biceps muscle showed a necrotizing vasculitis with fibrinoid necrosis, consistent with PAN.

CONCLUSIONS

Polyarteritis nodosa can produce ischemia of a variety of ocular structures, including the retina, choroid, and optic nerve. In our patient, all three structures were affected. To our knowledge, this is the first reported case of the triangular sign of Amalric in PAN.

Role of hypothalamic neuropeptide Y (NPY) in the change of feeding behavior induced by repeated treatment of amphetamine

Neuropeptide Y (NPY), an orexigenic peptide, is involved in the control of food intake. Repeated administration of amphetamine (AMPH), an anorectic agent, results in an anorectic effect on day 1 and a tolerant anorectic effect on the followings. In an attempt to know the role of hypothalamic NPY in these effects of AMPH, contents of hypothalamic NPY were determined by radioimmunoassay at first. In AMPH-treated groups, the contents of hypothalamic NPY decreased rapidly on day 1 but restored gradually to the normal level on the following days as observed in repeated AMPH. An involvement of hypothalamic NPY in the feeding change of repeated AMPH can thus be considered. Moreover, daily injection of NPY antisense oligonucleotide into brain (10 microg/10 microl/day, i.c.v.) to inhibit the gene expression of hypothalamic NPY were performed at 1 hour before daily 2 mg/kg AMPH. The reversion of food intake from the anorectic level to the normal level (tolerant anorexia) was abolished by this antisense pretreatment. It is suggested that hypothalamic NPY may play a role in the change of feeding behavior induced by repeated AMPH administration.

Endoscopic comparison of the gastroduodenal safety and the effects on arachidonic acid products between meloxicam and piroxicam in the treatment of osteoarthritis

Our objective was to evaluate the efficacy, the gastroduodenal safety, and the effects on arachidonic acid products of meloxicam, a new acidic enolic non-steroidal anti-inflammatory drug which preferentially inhibits cyclo-oxygenase-2 over cyclo-oxygenase-1, versus piroxicam in patients with osteoarthritis of the knee. Meloxicam 7.5 mg or piroxicam 20 mg daily was administered for 4 weeks in this double-blind parallel-groups randomised study. The efficacy for pain relief of the two tested medications was assessed by means of visual analogue scale and other clinical parameters. Pre- and post-treatment endoscopies were performed, and the findings were scored and recorded. The gastric fluid was aspirated at each time and prostaglandin E2, thromboxane B2 and leukotriene B4 were determined by ELISA. There was no significant difference between the groups regarding the primary efficacy. Changes in endoscopic findings by means of Lanza score showed statistically significant differences between the two treatment groups in favour of meloxicam at all sites--gastric, duodenal and total. Within-group comparisons showed a statistically significant difference (worsening) in gastric and total score with piroxicam, but no significant difference with meloxicam. The frequency of clinically relevant cases (total score >2) also showed a statistically significant worsening in the piroxicam group. The better GI tolerability of meloxicam was also suggested by fewer adverse GI events and no withdrawals due to adverse events compared with piroxicam. The pre-/post-study gastric juice concentration of PGE2, TXB2, and LTB4 in the meloxicam group was 135.2 +/- 85.8/71.2 +/- 32.2, 116.3 +/- 81.7/99.4 +/- 107.5 and 388 +/- 321/223 +/- 98 pg/ml respectively. The pre-/post-study gastric juice concentration of PGE2, TXB2 and LTB4 in the piroxicam group was 105.7 +/- 43.1/68.2 +/- 34.9, 94.0 +/- 50.9/105.9 +/- 121.1 and 625 +/- 1574/828 +/- 1464 pg/ml, respectively. Both meloxicam and piroxicam significantly inhibited gastric PGE2 levels after 4 weeks' treatment; however, there was no difference between these two groups. Neither of these medications had an effect on TXB2. Only meloxicam inhibited LTB4 concentration significantly, and the between-groups difference was significant. Meloxicam 7.5 mg once daily had better gastrointestinal tolerability and an efficacy comparable to that of piroxicam 20 mg over 4 weeks in patients with osteoarthritis of the knee.

Prognostic value of nm23 expression in stage IB1 cervical carcinoma

BACKGROUND

The purpose of this retrospective study was to evaluate the patterns of nm23 expression in stage IB1 squamous cell carcinoma of the uterine cervix, to compare nm23 expression with clinicopathological findings and to assess its prognostic value.

METHODS

Twenty-seven patients with stage IB1 squamous cell carcinoma of the uterine cervix underwent abdominal radical hysterectomy and pelvic lymph node dissection. Expression of nm23 was studied immunohistochemically, followed by amplification and direct sequencing of exons 4 and 5 of the nm23 gene.

RESULTS

Overexpression of nm23 was detected in 18.5% of the tumors and low expression was seen in 33.3%, while negative expression was found in 48.1% of the tumors. Deep cervical stromal invasion (> or =1/2) was found to be associated with the increased risk of lymph node metastases (odds ratio = 17.5). A significantly lower percentage of patients survived when nm23 overexpression was observed (p = 0.0063). Univariate analysis revealed that tumor size (2-3.9 cm), lymph node metastasis, tumor invasion into parametria, tumor invasion into blood/lymph vessel, squamous cell carcinoma (> or =2 ng/ml) and nm23 overexpression had a significantly lower recurrence-free survival rate of the patients. None of the above factors was significant according to multivariate analysis. There were no mutations in exons 4 and 5 of the nm23 gene in stage IB1 squamous cell carcinoma of the uterine cervix.

CONCLUSIONS

This study suggests that expression of nm23 may be indicative of an unfavorable prognosis in patients with stage IB1 squamous cell carcinoma of the uterine cervix.

The sympathetic nervous system promotes carbon tetrachloride-induced liver cirrhosis in rats by suppressing apoptosis and enhancing the growth kinetics of regenerating hepatocytes

Norepinephrine is considered to possess potent anti-apoptotic action in regenerating hepatocytes. To clarify the role of the sympathetic nervous system in apoptosis that occurs in chronic liver damage and following the promotion of liver cirrhosis, we studied a carbon tetrachloride (CCl4)-induced liver injury model, using spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY), and chemically sympathectomized WKY. At 24 h after CCl4 administration. acute damage, characterized by vacuolated hepatocytes in the centrilobular zone, was greater in SHR than in WKY. This vacuolated change in WKY hepatocytes was significantly reduced by chemical sympathectomy with 6-hydroxydopamine (6-OHDA). After 48 h, the acute damage was dramatically improved in each animal, without significant differences between the three groups. In chronic damage after weekly repetition of CCl4 treatment for 4 weeks, fibrosis was evident in SHR, while in the other groups there was only scant fibrosis in the centrilobular zone. After 8 weeks' repetition of CCl4, liver cirrhosis was seen only in SHR. The incidence of apoptotic cells in areas of both acute and chronic damage in WKY, detected by terminal deoxynucleotidyl transferase-dUTP nick end labeling, was significantly increased in comparison with that in SHR, and was further increased by 6-OHDA pretreatment. In contrast, there was significantly greater enhancement of the growth of hepatocytes in SHR than in WKY in both acute and chronic damage. Moreover. hepatocyte growth kinetics in WKY was significantly inhibited after sympathectomy in acute injury, as evidenced by immunohistochemistry for proliferating cell nuclear antigen (PCNA). In vitro, the amount of hepatocellular apoptosis induced by transforming growth factor-beta1 was significantly decreased by incubation with norepinephrine. These findings suggest that the anti-apoptotic effect of the sympathetic nervous system increases cell growth kinetics and promotes liver cirrhosis in this animal model.

Prognostic value of p53 expression in stage IB1 cervical carcinoma

The purpose of this retrospective study was to evaluate the patterns of p53 expression in stage IB1 squamous cell carcinoma of the uterine cervix, to compare p53 expression with clinicopathological findings, and to assess its prognostic value. 27 patients with stage IB1 squamous cell carcinoma of the uterine cervix underwent abdominal radical hysterectomy and pelvic lymph node dissection. Expression of p53 was studied immunohistochemically. Overexpression of p53 was detected in 33.3% of the tumors, low expression was seen in 11.1%, and negative expression was found in 55.6%. Deep cervical stromal invasion (> or = 1/2) was found to be associated with the increased risk of lymph node metastases (odds ratio = 17.5). A significantly lower percentage of patients survived when p53 overexpression was observed (p = 0.0315). Univariate analysis revealed that tumor size (2-3.9 cm), lymph node metastasis, tumor invasion into parametria, tumor invasion into blood/lymph vessels, squamous cell carcinoma antigen (> or = 2 ng/ml), and p53 overexpression had a significantly lower recurrence-free survival rate. None of these above factors obtained significance in the multivariate analysis. This study suggests that expression of p53 may be indicative of an unfavorable prognosis in patients with stage IB1 squamous cell carcinoma of the uterine cervix.

Vaccination against gonadotropin-releasing hormone (GnRH) using toxin receptor-binding domain-conjugated GnRH repeats

A method for the preparation of an immunogen containing multiple copies of a self-peptide in linear alignment was designed in order to overcome the difficulty of inducing an immune response to poorly immunogenic peptide antigens. DNA fragments encoding multiple repeats of the self-peptide were generated by a new technique, termed template-repeated polymerase chain reaction (TR-PCR), which could be subcloned into an expression vector for production of peptide repeats as an immunogen. This approach was tested by constructing fusion proteins containing the receptor-binding domain of Pseudomonas exotoxin A and multiple copies of the 10-residue sequence of the peptide hormone gonadotropin-releasing hormone (GnRH). Immunization of female rabbits with the immunogen that contained the exotoxin receptor-binding domain and 12 copies of GnRH (PEIa-GnRH12) resulted in the generation of high-titer antibodies specific for GnRH. Although at equal molar basis of the GnRH moiety, the immunogen that contained single copy of GnRH (PEIa-GnRH1) induced low-titer anti-GnRH antibodies. These observations suggest that the presence of multiple peptide repeats is a key factor in eliciting an immune response. In addition, anti-GnRH antibodies effectively neutralized GnRH activity in vivo, as demonstrated by the degeneration of the ovaries in the injected rabbits. Because anti-GnRH antibody could be functionally analogous to GnRH antagonist, which has been used to treat patients with ovarian cancer, vaccination of PEIa-GnRH12 presents a potential therapeutic application for the treatment of GnRH-sensitive ovarian cancer.

Bcl-2 accelerates retinoic acid-induced growth arrest and recovery in human gastric cancer cells

The role of Bcl-2 as an anti-apoptotic protein has been well documented. In the present work, we present evidence that Bcl-2 may also be involved in cell growth regulation. SC-M1 is an unique cell line which responds to retinoic acid (RA) treatment with reversible growth arrest [Shyu, Jiang, Huang, Chang, Wu, Roffler and Yeh (1995) Eur. J. Cancer 31, 237-243]. In this study, when treated with RA, SC-M1/Bcl2 cells, which were generated by transfecting SC-M1 cells with bcl-2 DNA, were growth-arrested two days earlier than SC-M1/neo cells, which were generated by transfecting SC-M1 cells with vector DNA. This indicates that Bcl-2 accelerates RA-induced growth arrest. In addition to the accelerated growth arrest, RA-treated SC-M1/Bcl2 cells also recovered from growth arrest two days faster than SC-M1/neo cells after the removal of RA. Previously, we had identified the cyclin-dependent kinase inhibitor p21((WAF1/CIP1)) (p21) as a mediator of RA-induced growth arrest [Tsao, Li, Kuo, Liu and Chen (1996) Biochem. J. 317, 707-711]. In a search for the mechanism by which Bcl-2 affects growth regulation, we found that p21 gene expression was more prominent in SC-M1/Bcl2 cells than in SC-M1/neo cells in the presence of RA, but when RA was removed, p21 gene expression levels in SC-M1/Bcl2 cells were also reduced earlier than in SC-M1/neo cells. The present report is the first to show that Bcl-2 accelerates not only growth arrest but also recovery from growth arrest. Moreover, the close correlation between the effect of Bcl-2 on both RA-induced growth arrest and RA-induced p21 gene expression suggests the possibility that Bcl-2 affects cell growth through the mechanism of p21.

Development of DNA delivery system using Pseudomonas exotoxin A and a DNA binding region of human DNA topoisomerase I

Gene therapy is defined as the delivery of a functional gene for expression in somatic tissues with the intent to cure a disease. Thus, highly efficient gene transfer is essential for gene therapy. Receptor-mediated gene delivery can offer high efficiency in gene transfer, but several technical difficulties need to be solved. In this study, we first examined the DNA binding regions of the human DNA topoisomerase I (Topo I), using agarose gel mobility shift assay, in order to identify sites of noncovalent binding of human DNA Topo I to plasmid DNA. We identified four DNA binding regions in human DNA Topo I. They resided in aa 51-200, 271-375, 422-596, and 651-696 of the human DNA Topo I. We then used one of the four regions as a DNA binding protein fragment in the construction of a DNA delivery vehicle. Based on the known functional property of each Pseudomonas exotoxin A (PE) domain and human DNA Topo I, we fused the receptor binding and membrane translocation domains of PE with a highly positively charged DNA binding region of the N-terminal 198 amino acid residues of human DNA Topo I. The resulting recombinant protein was examined for DNA binding in vitro and transfer efficiency in cultured cells. The results show that this DNA delivery protein is a general DNA delivery vehicle without DNA sequence, topology, and cell-type specificity. The DNA delivery protein could be used to target genes of interest into cells for genetic and biochemical studies. Therefore, this technique can potentially be applied to cancer gene therapy.

Superoxide dismutase gene expression and activity in the brain of spontaneously hypertensive rats and normotensive rats

OBJECTIVE

To determine if changes in superoxide dismutase (SOD) in the brain occur in the hypertensive state.

METHODS

We compared the levels of the two main subtypes of this enzyme in spontaneously hypertensive rats (SHR) with age-matched normotensive Wistar Kyoto (WKY) rats using enzyme activity estimation, Western blotting for enzyme contents, and Northern blotting of mRNA level. Five discrete brain regions, cerebrocortex, hypothalamus, hippocampus, the remaining non-cortex cerebrum (NCC area), and cerebellum, were employed for comparison in 30-31 weeks old rats.

RESULTS

A lower level of both Mn-SOD activity and Mn-SOD mRNA expression was found in all areas of the brain of SHR as compared with WKY rats. Also, the mRNA levels of Cu, Zn-SOD in the brain of SHR differed from WKY rats in parallel to the enzyme activities. The activity and mRNA expression of Cu, Zn-SOD were lower in the hypothalamus and cerebellum of SHR but the mRNA level and the activity in hippocampus were significantly higher in the SHR compared to WKY rats. No differences for Cu, Zn-SOD were observed in cerebrocortex or NCC area in the two species. However, the amount of SOD enzyme subtypes, determined by Western blotting analysis, was not different between SHR and WKY rats.

CONCLUSIONS

The results indicate a lower gene expression and less activity of Mn-SOD in SHR brain. This alternation of SOD may be one of the important factors for the vulnerability of the brain from oxygen free radicals or may be related to the pathogenesis of hypertension in this species.

Tumor seeding of the jejunostomy site after transhiatal esophagectomy for esophageal carcinoma

A 65-year-old male patient with squamous cell carcinoma of the esophagus had a transhiatal esophagectomy after a prophylactic tube jejunostomy. The tube was removed 3 weeks after surgery. Ten months later, a painless 2-cm abdominal mass was noted at the previous jejunostomy site. Subsequent segmental resection of the jejunum disclosed metastatic squamous cell carcinoma of the esophagus. It is possible that tumor seeding may develop at the jejunostomy site after transhiatal esophagectomy for esophageal carcinoma.

Educational puzzles for understanding gastrointestinal physiology

We developed four innovative, creative, and fun educational tools to promote active learning, enhance problem-solving skills, and encourage small group discussion. Furthermore, the tools encourage deductive reasoning and critical thinking rather than passive memorization of material. The tools include crossword puzzles, hidden messages, word scrambles, and word searches. These tools were developed using two computer programs: the Crossword Construction Kit and The New Puzzle Factory. Instructors are encouraged to optimize the value of the tools by using the additional options presented at the end of each of the puzzles. The additional options encourage students to become active learners by creating their own tools. Although the principles of these four tools can be adapted to many disciplines, these specific games focused on gastrointestinal physiology. Our goal was to create tools that can be used either inside or outside the classroom to complement and enhance the lecture.

"Virtual rat": a tool for understanding hormonal regulation of gastrointestinal function

This manuscript describes a "dry laboratory" using the "virtual rat" to help students understand the hormonal regulation of gastrointestinal function. The laboratory was modeled after a recent exercise that used the virtual rat to teach basic endocrine physiology. The virtual rat concept avoids the many obstacles associated with animal experimentation (for example, lack of adequate animal facilities, expense, equipment, and limited teacher experience). Our goal was to create a fun and educational experience while avoiding the complications associated with laboratory experimentation. No additional materials are required to complete this exercise. After finishing this laboratory, the students should have a greater understanding and appreciation for experimental design and the collection, analysis, and interpretation of data.