[Origin and progress of myelodysplastic syndrome with hypoplasia]

OBJECTIVE

To study the origin and progress of myelodysplastic syndrome (MDS) with hypoplasia.

METHODS

The data of twenty-five cases of hypomyeloplastic MDS diagnosed by our department in the last ten years were analyzed. 17 of the 25 cases were followed up for a long time.

RESULTS

(1) The percentage of hypomyeloplastic MDS was 11.4% of the total 219 MDS patients. The median age of the 25 cases was (44.8 +/- 14.7) years. (2) FAB subtype: There were 11 cases of RA and 14 of RAEB. (3) Hypomyeloplastic MDS seems to be a developmental phase in the clinical course in some of the patients and not a special type of MDS. Hyper- and hypo-myeloplasia could be transformed from one to another. The transformation of myelodysplasia could occur either in the same or and different FAB subtype. (4) Seven of the seventeen cases transformed to acute leukemia (41.2%), 6 cases were AML and 1 was ALL. 3 of the 7 cases transformed to hypomyeloplastic leukemia and the remaining 4 transformed to hypermyeloplastic leukemia. (5) The median time from the diagnosis of RAEB to leukemia transformation, was 27 months in 7 cases with hypoplastic RAEB. (6) No relationship was found between therapeutic medicines and development of hypomyeloplastic MDS.

CONCLUSION

It is suggested that hypomyeloplastic MDS is probably a developmental phase in the clinical course of MDS, but not a special type.

Study of loss of heterozygosity at DCC and APC/MCC genetic loci of gastric cancer

In order to assess the role of the changes of DCC and APC/MCC genes in the development and progression of gastric cancer, the loss of heterozygosity (LOH) of these genetic loci was investigated in 45 surgical specimens of gastric cancer with PCR-RFLP. The rate of LOH was 30.0% (9/30) at APC/MCC gene and 33.3% (15/45) at DCC gene. LOH was found in both intestinal and gastric types of gastric cancer and the rate of LOH of DCC gene was significantly higher in stages III to approximately IV gastric cancer (48.0%) than in stages I to approximately II (15.0%) (P<0.05). LOH of APC/MCC gene could be found in both early and advanced stages of gastric cancer. These findings suggest that changes of DCC and APC/MCC genes are involved in the development and progression of the intestinal and gastric types of gastric cancer.

Surface roughness from highlight structure

Highlights are due to specular reflection and cause the lustrous or mirrorlike appearance of many material surfaces. We investigated in detail the structure of highlight patterns that are due to material surface roughness. We interpret results in terms of a simple model of a random Gaussian surface. The model's prediction corresponds with the microscopic measurement within a factor of 2. The method allows one to rank generally the roughness of the surfaces of the fruit samples by purely optical means. This simple procedure for estimating surface roughness from images has implications for visual perception and graphic rendering.

Protection of calcitonin gene-related peptide-mediated preconditioning against coronary endothelial dysfunction induced by reperfusion in the isolated rat heart

This study was designed to explore the protective effect of ischemic preconditioning on reperfusion-induced coronary endothelial dysfunction, with a focus on the role of calcitonin gene-related peptide (CGRP) in this effect, in the isolated perfused rat heart. Thirty minutes of global ischemia and 30 min of reperfusion significantly decreased heart rate, left ventricular pressure, and its first derivative and impaired vasodilator responses to acetylcholine. Ischemia-reperfusion did not affect vasodilator responses to sodium nitroprusside. Preconditioning induced by three cycles of 5 min of ischemia and 5 min of reperfusion produced a significant improvement in cardiac function concomitantly with an amelioration of vasodilator responses to acetylcholine. The protective effects of ischemic preconditioning were abolished by CGRP(8-37) (10(-7) M) , the selective CGRP receptor antagonist. After pretreatment with capsaicin (50 mg x kg(-1), s.c.) to deplete endogenous CGRP, the preconditioning effect was absent. Pretreatment with exogenous CGRP (5 x 10(-9) M) for 5 min induced a preconditioning-like protection. The present study suggests that the cardioprotection of ischemic preconditioning is related to the preservation of the coronary endothelial cell, and that the protective effect of preconditioning is mediated by endogenous CGRP in the isolated perfused rat heart.

Lithium attenuates p53 levels in human neuroblastoma SH-SY5Y cells

Lithium has neuroprotective effects in a number of model systems which may contribute to the therapeutic effects of lithium in mood disorders. Because the tumor suppressor p53 is linked to cell death, we tested whether lithium administration to human neuroblastoma SH-SY5Y cells modulated the activation of p53. After treatment of cells with H7 (25, 50, and 75 microM), nuclear p53 levels were increased to 464, 816 and 1079% of basal levels, respectively. A 24 h pretreatment with 5 mM lithium reduced these increases by 69, 61 and 28%, respectively. Pretreatment with 2 mM lithium for 1 or 14 days reduced the 25 microM H7-induced elevations of nuclear p53 by 40 and 70%, respectively, and even a 14-day pretreatment with 1 mM lithium caused a significant 16% reduction. Since increased nuclear p53 is a critical intermediate step in many signaling processes that culminate in cell death, attenuation of p53 activation by lithium reveals a mechanism by which lithium may support neuronal survival.

[The detection of microsatellite instability in carcinoma and adenoma of large bowel and its significance]

OBJECTIVE

To explore the role of microsatellite instability (MSI) in colorectal carcinogenesis and the relationship between MSI, proliferation activity and prognosis.

METHODS

PCR-SSLP and immunohistochemistry methods were used to detect MSI and the expression of PCNA in 56 cases of carcinomas, 9 cases of adenomas and 6 cases of adenomas with malignant changes.

RESULTS

The total positive rate of MSI were 25/56 cases in colorectal carcinomas. The MSI positive cases were 3/4 in HNPCCs, 22/52 in sporadic colorectal carcinomas, 2/9 in adenomas and 2/6 in adenoma with malignant changes respectively. The PCNA labelling index of MSI positive tumors were significantly lower than that of MSI negative tumors (P < 0.01). The 3 and 5 year survival rates in patients with MSI positive colorectal carcinomas were higher than those of MSI negative tumors.

CONCLUSION

MSI may be an early molecular alteration and another molecular mechanism in colorectal carcinogenesis. The MSI positive tumors have low proliferating activity and a better clinical outcome. The detection of MSI might be useful in predicting prognosis of colorectal carcinomas.

Detection of telomerase activity in biopsy samples of colorectal cancer

BACKGROUND

Telomerase is a ribonucleoprotein that synthesizes telomeric DNA onto chromosomal ends. The expression of telomerase is thought to be required for cellular immortality and oncogenesis.

METHODS

To investigate the role of telomerase in the pathogenesis of colorectal cancer, we analysed telomerase activity in biopsy samples of colorectal cancer and colonic adenomas. Using a polymerase chain reaction-based assay, we examined telomerase activity in 52 samples of colorectal cancer, 12 colonic adenomas and 30 normal colonic mucosa samples obtained by endoscopic biopsy.

RESULTS

Telomerase activity was detectable in 88.5% (46/52) of colorectal carcinomas, in 50% (6/12) of colonic adenomas but not in normal colorectal mucosa. There was no correlation between telomerase activity and tumour location, type, size and differentiation (P > 0.05).

CONCLUSIONS

It was concluded that telomerase activation plays a role in the evolution of colorectal cancer, and that measurement of telomerase activity in biopsied colorectal mucosa samples may provide information both as a diagnostic marker to detect small numbers of cancer cells, and as a screening method for patients at high risk for colorectal carcinoma.

Stimulation of PC cell-derived growth factor (epithelin/granulin precursor) expression by estradiol in human breast cancer cells

PC cell-derived growth factor (PCDGF) is an 88 kDa glycosylated protein isolated from a highly tumorigenic mouse teratoma derived cell line which is similar to the epithelin/granulin precursor. Using Northern blot and western blot analyses, we detect the expression of PCDGF mRNA and protein in MCF-7 human breast cancer cells. We show that 17-beta-estradiol stimulates PCDGF mRNA and protein expression in a time and dose-dependent manner. The stimulation of PCDGF expression by 17-beta-estradiol was observed as early as 4 hours and reached a maximum at 12 hours. Maximal stimulation of PCDGF mRNA and protein expression by 17-beta-estradiol was observed at a concentration of 10(-8) M. The stimulation of PCDGF expression by 17-beta-estradiol was completely inhibited by treatment with actinomycin D and with the antiestrogen 4-hydroxytamoxifen. The stimulation of PCDGF expression was also demonstrated in another human estrogen-responsive cell line T47D. The results presented here provide evidence of a novel estradiol responsive gene product in human breast cancer cell lines and give information about the hormonal control of epithelin/granulin (PCDGF) expression in these cells.

[Morphological changes and electrophysiological study of motor neuron of spinal cord following delayed repair of peripheral nerve injury]

OBJECTIVE

Following the delayed repair of peripheral nerve injury, the cell number of anterior horn of the spinal cord and its ultrastructural changes, motorneuron and its electrophysiological changes were investigated.

METHODS

In 16 rabbits the common peroneal nerves of both sides being transected one year later were divided into four groups randomly: the degeneration group and regeneration of 1, 3 and 5 months groups. Another 4 rabbits were used for control. All transected common peroneal nerves underwent epineural suture except for the degeneration group the electrophysiological examination was carried out at 1, 3 and 5 months postoperatively. Retrograde labelling of the anterior horn cells was demonstrated and the cells were observed under light and electronmicroscope.

RESULTS

1. The number of labelled anterior horn cell in the spinal cord was 45% of the normal population after denervation for one year (P < 0.01). The number of labelled cells increased steadily from 48% to 57% and 68% of normal values at 1, 3 and 5 months following delayed nerve repair (P < 0.01). 2. The ultrastructure of the anterior horn cells of the recover gradually after repair. 3. With the progress of regeneration the latency become shortened, the conduction velocity was increased, the amplitude of action potential was increased.

CONCLUSION

Following delayed repair of injury of peripheral nerve, the morphology of anterior horn cells of spinal cord and electrophysiological display all revealed evidence of regeneration, thus the late repair of injury of peripheral nerve was valid.

Oxygen free radicals in interleukin-1beta-induced glycosaminoglycan production by retro-ocular fibroblasts from normal subjects and Graves' ophthalmopathy patients

Graves' ophthalmopathy (GO) is attributed to an autoimmune process that results in the accumulation in retro-ocular tissue of glycosaminoglycans (GAG) that are in turn responsible for the development of clinical signs and symptoms. Retro-ocular fibroblasts are thought to be the source of GAG production and deposition in GO. In the present study, we investigated interleukin (IL)-1beta-induced oxygen free radical production and the role of oxygen free radicals in IL-1beta-induced GAG production in retro-ocular fibroblasts from both normal subjects and patients with GO. Normal retro-ocular fibroblasts demonstrated no measurable oxygen free radicals whereas GO retro-ocular fibroblasts showed detectable signals by electron paramagnetic resonance (EPR) spectroscopy. IL-1beta increased the free radical production in both cells. Superoxide dismutase (SOD) activity in GO retroocular fibroblasts was higher than that in normal cells. IL-1beta dose- and time-dependently stimulated the SOD activity in both cells, with GO retro-ocular fibroblasts showing less responsiveness. IL-1beta dose-dependently increased [3H]glucosamine incorporation into GAG by both cells. An exogenous oxygen free radical-generating system failed to increase GAG. Scavenging oxygen free radicals by the use of SOD (100 U/mL) and catalase (300 U/mL) partially blocked the IL-1beta-induced GAG production in both cells. These results suggest that stress related oxygen free radicals are present in the retro-ocular tissue in GO and that oxygen free radicals are involved in GAG accumulation induced by cytokine IL-1beta.

Cloning of the human kidney PAH transporter: narrow substrate specificity and regulation by protein kinase C

Conserved from fish to mammals, renal proximal tubule organic anion secretion plays an important role in drug and xenobiotic elimination. Studies with the model substrate p-aminohippurate (PAH) have suggested that a basolateral PAH/alpha-ketoglutarate exchanger imports diverse organic substrates into the proximal tubule prior to apical secretion. cDNAs encoding PAH transporters have been cloned recently from rat and flounder. Here we report the cloning of a highly similar human PAH transporter (hPAHT) from human kidney. By Northern blot analysis and EST database searching, hPAHT mRNA was detected in kidney and brain. PCR-based monochromosomal somatic cell hybrid mapping placed the hPAHT gene on chromosome 11. When expressed transiently in vitro, hPAHT catalyzed time-dependent and saturable [3H]PAH uptake (Km of approximately 5 microM). Preincubation with unlabeled alpha-ketoglutaric or with glutaric acid stimulated tracer PAH uptake, and preincubation with unlabeled PAH stimulated tracer alpha-ketoglutarate uptake, results that are consistent with PAH/alpha-ketoglutarate exchange. Several structurally diverse organic anions cis-inhibited PAH uptake. Like rat OAT1 organic anion transporter, hPAHT was inhibited by furosemide, indomethacin, probenecid, and alpha-ketoglutarate. Unlike OAT1, hPAHT was not inhibited by prostaglandins or methotrexate (MTX). Moreover, tracer PGE2 and MTX were not transported, indicating that the substrate specificity for transport by hPAHT is not broad. PAH uptake was inhibited by phorbol 12-myristate 13-acetate (PMA) in a dose- and time-dependent fashion, but not by the inactive 4alpha-phorbol-12,13 didecanoate. PMA-induced inhibition was blocked by staurosporine. Thus the protein kinase C-mediated inhibition of basolateral organic anion entry previously reported in intact tubules is likely due, at least in part, to direct modulation of the PAH/alpha-ketoglutarate exchanger.

[Deletion analysis and functional studies of the promoter from commelina yellow mottle virus]

Commelina Yellow Mottle Virus(CoYMV) is a double-stranded, circular DNA virus and its promoter could direct GUS gene specifically expressing in phloem tissue of transgenic tobacco plants. To determine the optimal promoter sequence for pholem-specific gene expression, CoYMV promoter was deleted from its 5 end to form promoter fragments with 5 different lengths. Chimeric GUS genes were constructed using the promoter deletion based on the binary vector pBI121. Transgenic tobacco plants evidenced by PCR analysis were obtained with each kind of chimeric GUS gene structure by Agrobacterium mediated transformation. The results of GUS activity assay and histo-chemical staining showed that most of the chimeric GUS genes were expressed in transgenic plants. The GUS activity with the promoter deleted to -870 bp was about 78% higher than that of the full length promoter(1040 bp) and was a little higher than that of the promoter deleted to -585 bp, but the difference is not significant. The GUS activity reduced significantly when the promoter was deleted to -447 bp or -232 bp, whereas the property of phloem-specific expression pattern was still retained. When the promoter was deleted to -44 bp, just upstream adjacent to the TATA box, its tissue-specificity was lost and the activity was reduced to undetectable level. These results suggest that the region between -870 bp-232 bp and downstream of -232 bp of CoYMV promoter could be responsible for promoter activity and tissue specific expression, respectively. A negative regulation sequence might exist upstream of -870 bp of the CoYMV promoter. Therefore, we recommend that the optional CoYMV promoter sequence for phloem specific expression could be downstream from -870 bp or -585 bp. In comparison with CaMV 35S promoter, the GUS activity when driven by -870 bp CoYMV promoter was about 70% of that when driven by the 35S promoter. Considering the fact that 35S promoter-GUS gene is constitutively expressed, while the CoYMV promoter-GUS gene is expressed only in phloem tissues, the activity of the latter in phloem may be the same with or even higher than that of the 35S promoter.

[The possible role of loss of heterozygosity at APC, MCC and DCC genetic loci in esophageal carcinoma]

OBJECTIVE

To investigate the alterations of APC, MCC and DCC genes in human esophageal carcinoma.

METHODS

A total of 46 human esophageal cancer specimens were analyzed for the loss of heterozygosity (LOH) at APC, MCC and DCC genetic loci by means of polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

The incidence of LOH was 29.0%(9/31) at APC locus, 33.3%(8/24) at MCC locus, and 32.4%(12/37) at DCC locus, respectively. However, there was no statistically significant correlation between LOH at these three loci with such clinical parameters as pathological types, tumor size, invasiveness, and lymph-node metastasis.

CONCLUSION

These data suggest that LOH at APC, MCC and DCC loci in esophageal carcinoma is, to certain extent, a common genetic alteration which might play a role in esophageal carcinogenesis.

Transgenic knockout mice exclusively expressing human hemoglobin S after transfer of a 240-kb betas-globin yeast artificial chromosome: A mouse model of sickle cell anemia

Sickle cell anemia (SCA) and thalassemia are among the most common genetic diseases worldwide. Current approaches to the development of murine models of SCA involve the elimination of functional murine alpha- and beta-globin genes and substitution with human alpha and betas transgenes. Recently, two groups have produced mice that exclusively express human HbS. The transgenic lines used in these studies were produced by coinjection of human alpha-, gamma-, and beta-globin constructs. Thus, all of the transgenes are integrated at a single chromosomal site. Studies in transgenic mice have demonstrated that the normal gene order and spatial organization of the members of the human beta-globin gene family are required for appropriate developmental and stage-restricted expression of the genes. As the cis-acting sequences that participate in activation and silencing of the gamma- and beta-globin genes are not fully defined, murine models that preserve the normal structure of the locus are likely to have significant advantages for validating future therapies for SCA. To produce a model of SCA that recapitulates not only the phenotype, but also the genotype of patients with SCA, we have generated mice that exclusively express HbS after transfer of a 240-kb betas yeast artificial chromosome. These mice have hemolytic anemia, 10% irreversibly sickled cells in their peripheral blood, reticulocytosis, and other phenotypic features of SCA.

[A computer system for bone age measurement of hand radiographs]

OBJECTIVE

This study was to development a computer system for assessing bone age which would analyse children's growth level accurately and quickly.

METHODS

It used the standards of estimating skeletal maturity for Chinese (CHN) scoring method to assess the bone age of Chinese children. We applied image enhancement techniques for imprving the quality of the hand-wrist radiographs, while an automated system was developed to implement this method.

RESULTS

Users could get a clear and reliable radiograph through image processing, compare each bone of the hand-wrist radiograph with that of the scanned image of the standard radiographs, then generate the stage of bone maturity. The computer would give out individual and total bone score and a value of bone age.

CONCLUSION

This system implemented evaluation of bone age rapidly and accurately, it would help orthodontist to choose the best time of treatment.

Characterization of cembranoid interaction with the nicotinic acetylcholine receptor

The class of diterpenoids with a 14-carbon cembrane ring, the cembranoids, includes both competitive and noncompetitive inhibitors of the nicotinic acetylcholine receptor (AChR). All 20 coelenterate-derived cembranoids studied in this report inhibited [piperidyl-3,4-3H]-phencyclidine ([3H]-PCP) binding to its high-affinity site on the electric organ AChR, with IC50s ranging from 0.9 microM for methylpseudoplexaurate to 372 microM for lophotoxin. Inhibition was complete with all cembranoids but lophotoxin and most Hill coefficients were close to 1. Methylpseudoplexaurate and [3H]-PCP binding was competitive. Methylpseudoplexaurate and the fourth most potent cembranoid, eunicin, competed with each other for [3H]-PCP displacement, indicating that there exist one or more cembranoid sites on the AChR. Cembranoid affinity for the AChR correlated with hydrophobicity, but was also dependent on other features. Methylpseudoplexaurate and n-octanol also competed with each other for [3H]-PCP displacement, indicating that the cembranoid site is linked to the n-octanol site on the AChR. Unlike lophotoxin, the five cembranoids tested did not inhibit [125I]Tyr54-alpha-bungarotoxin binding to the AChR agonist sites. All seven cembranoids tested on oocyte-expressed electric organ AChR reversibly blocked acetylcholine-induced currents, although the inhibitor concentration curves were shallow and the inhibition was incomplete.

[Immunohistochemical investigations of congenital pseudarthrosis of the tibia]

OBJECTIVE

To investigate the etiology and pathology of congenital pseudarthrosis.

METHOD

Sixty-three specimens were taken from 21 CPT patients. The antibodies, which were used for immunohistochemical studies, were produced against (1) NF-200 or S-100 protein; (2) type I or III collagen; (3) PCNA. The control specimens were taken from neurofibromatosis and traumatic pseudarthrosis. SABC staining was performed.

RESULT

Low positive expression of NF-200 (3.2%) and S-100 (4.8%) was noted in the CPT lesion, whereas high expression of NF-200 (85.2%) and S-100 (88.9%) in the lesion of neurofibromatosis. The soft tissues in CPT had a higher ratio of type III to I collagens in comparison with traumatic pseudarthrosis. Positive expression of PCNA (95.2%) was significantly higher in the soft tissues than that (2.5%) in traumatic pseudarthrosis.

CONCLUSION

CPT is a disease of non-neuro origin. Its occurrence has no direct relation with neurofibromatosis. CPT has its characteristic pathology in the periosteum rather than in the bone. The pathological fracture or non-union of CPT is caused by fibromatosis, which has a strong activity of cellular proliferation and corrosion. CPT has its pathological property similar to a tumor.

[The osteoinductivity and the dose-effect relationship with implantation of reconstituted bone xenograft: experimental study]

OBJECTIVE

To observe osteoinductivity and the dose-effect relationship with administration of reconstituted bone xenograft (RBX).

METHOD

A posterior thigh muscle pouch model with RBX transplantation was established in BALB/C mice. Samples were treated at regular postoperative intervals for radiologic, histomorphologic and ALP examinations.

RESULT

(1) In the groups that had been implanted with RBX, the osteoinductivity was positively correlated with the bBMP contents in RBX (r = 0.7204, P < 0.01), showing a dose-dependent relationship; (2) satisfactory osteogenesis was noted in the RBX I group, whereas no substantial bone formation was seen in the group implanted with bBMP alone apart from some evidence of osteogenic effect; (3) the alkaline phosphatase activity attained its peak on the 7th day postoperatively and kept still higher to the 42nd day.

CONCLUSION

RBX is a highly osteoinductive grafting material with the treated homologous cancellous bone being a good slow-delivery carrier which can enhance the osteoinductive capacity of bBMP.

Optical properties (bidirectional reflection distribution functions) of velvet

A detailed investigation has been made of the unusual characteristics of the angular distribution of surface scattering from velvet in the visual region. We present a novel method in which samples of velvet fabric are wrapped around a right-circular cylinder so that reemitted radiance can be measured by a digital CCD camera. This setup makes it relatively simple to acquire a large set of bidirectional reflection distribution function (BRDF) samples. The study reveals that, apart from the grazing specular lobe and an anisotropic backscattering peak near 50 degrees , the overall BRDF's are rather uniform across the whole angular span of observation. Attempts are made to relate these scattering characteristics to the physical and the geometrical structure of velvet.

[Pathophysiology and surgical treatment on Relaxed Pelvic Floor Syndrome]

OBJECTIVE

To study the pathophysiology of the "Relaxed Pelvic Floor Syndrome (RPFS)" and to assess the value of the "Pelvic Cavity Fixation Operation (PCFO)" for the syndrome.

METHOD

11 patients, who were diagnosed as having RPFS, underwent standardized PCFO. All the patients were followed for a mean time of 19 months (5 - 72 months).

RESULT

The main syndromes and signs included difficulty in defecation, inability to empty the rectum properly, fullness of perineum, protrusion of perineum at bearing down, back-inclining uterus, relaxation of the rectum on digital examination. The anorectal dynamics showed that the sequence pressure and rest pressure of the anal cannel were lower and the time of contraction of the anal cannel decreased than that of the normal controls. The rectum sensation was damaged slightly. Defeacography showed that there were relaxing changes in several systems in the pelvic cavity. Operatively, it was easy to see the relaxation of the supporting structure of the colon, rectum, uterus and the lower position of the peritoneal cavity. PCFO has achieved good results. Seven patients were free of symptoms completely and 4 improved.

CONCLUSION

The relaxing changes of the supporting tissue of many viscus fefer to several systems are the pathophysiologic of the RPFS. "Pelvic Cavity Fixation Operation" is useful in the treatment of the syndrome.

The herpesvirus transactivator VP16 mimics a human basic domain leucine zipper protein, luman, in its interaction with HCF

In human cells infected with herpes simplex virus (HSV), viral gene expression is initiated by the virion protein VP16. VP16 does not bind DNA directly but forms a multiprotein complex on the viral immediate-early gene promoters with two cellular proteins: the POU domain protein Oct-1 and host cell factor (HCF; also called C1, VCAF, and CFF). Despite its apparent role in stabilizing the VP16-induced transcription complex, the natural biological role of HCF is unclear. Only recently HCF has been implicated in control of the cell cycle. To determine the role of HCF in cells and answer why HSV has evolved an HCF-dependent mechanism for the initiation of the lytic cycle, we identified the first human ligand for HCF (R. Lu et al., Mol. Cell. Biol. 17:5117-5126, 1997). This protein, Luman, is a member of the CREB/ATF family of transcription factors that can activate transcription from promoters containing cyclic AMP response elements (CRE). Here we provide evidence that Luman and VP16 share two important structural features: an acidic activation domain and a common mechanism for binding HCF. We found that Luman, its homolog in Drosophila, dCREB-A (also known as BBF-2), and VP16 bind to HCF by a motif, (D/E)HXY(S/A), present in all three proteins. In addition, a mutation (P134S) in HCF that prevents VP16 binding also abolishes its binding to Luman and dCREB-A. We also show that while interaction with HCF is not required for the ability of Luman to activate transcription when tethered to the GAL4 promoter, it appears to be essential for Luman to activate transcription through CRE sites. These data suggest that the HCF-Luman interaction may represent a conserved mechanism for transcriptional regulation in metazoans, and HSV mimics this interaction with HCF to monitor the physiological state of the host cell.

Molecular cloning of the gene for the human prostaglandin transporter hPGT: gene organization, promoter activity, and chromosomal localization

Prostaglandins (PGs) play diverse and important roles in human health and disease. We recently identified the first known PG transporter cDNA in the rat (PGT) and human (hPGT). To aid in the analysis of any possible human disease caused by mutations in PGT, we have cloned and characterized the hPGT gene. The gene exists as a single copy in the human genome and is comprised of 14 exons distributed over approximately 95 kb. Two introns disrupt putative trans-membrane spans of the coding region; each of these sites is near a highly conserved charged residue. The approximately 250 bp immediately 5' to the start of exon 1 contain a TATAAA sequence (TATA box), a transcription initiation (Inr) consensus (CTCANTCT), two Sp 1 sequences (GGGCGG), and a cAMP response element (CGGCGTCA). Ligation of approximately 3.5 kb of 5' flanking sequence to a luciferase reporter yielded > 15-fold activity above background when expressed in A549 human lung epithelial cells. PCR-based monochromosomal somatic cell hybrid mapping and fluorescence in situ hybridization localized hPGT to chromosome 3q21. Three microsatellites were identified, one of which was demonstrated to be polymorphic in unrelated individuals and may be useful in evaluating PGT as a candidate gene in human disease.

Targeted disruption of the ubiquitous CNC-bZIP transcription factor, Nrf-1, results in anemia and embryonic lethality in mice

The CNC-basic leucine zipper (CNC-bZIP) family is a subfamily of bZIP proteins identified from independent searches for factors that bind the AP-1-like cis-elements in the beta-globin locus control region. Three members, p45-Nf-e2, Nrf-1 and Nrf-2 have been identified in mammals. Expression of p45-Nf-e2 is largely restricted to hematopoietic cells while Nrf-1 and Nrf-2 are expressed in a wide range of tissues. To determine the function of Nrf-1, targeted disruption of the Nrf-1 gene was carried out. Homozygous Nrf-1 mutant mice are anemic due to a non-cell autonomous defect in definitive erythropoiesis and die in utero.

[Three dimensional reconstruction of human permanent teeth]

OBJECTIVE

Dental anatomy is one of the most important basic courses in the education of stomatology. The deep understanding of morphologic characters is closely instructive to the clinic of endodontics, oral surgery, orthodontics and prosthodontics.

METHODS

In present study, 32 permanent teeth from a skull specimen were inputted into computer after the processes of burying, grinding, photographing, scanning and recognizing. By the techniques of reconstruction, the 3D stereo tooth models were retrieved from 2D digital data.

RESULTS

On the basis of those 3D data, computer graphics techniques were used to realize the lighted, smoothed and shaded teeth.

CONCLUSION

Such a series of data teeth might be applicated as a corner stone of the computer aided instruction (CAI) in stomatology.

[Investigation of intrauterine microbes after intrauterine operation]

OBJECTIVE

To explore the postoperative changes in the cultures of ureaplasma urealyticum (UU), mycoplasma hominis (Mh), L-form bacteria (L-form), anaerobic bacteria (Ana) and chlamydia trochomatis (CT) after intrauterine operation.

METHODS

Four groups of patients were set up: group 1, induced abortion; group 2, intrauterine device (IUD) insertion; group 3, penicillin i.m. after IUD insertion; group 4, oral lincomycin after IUD insertion. Intrauterine secretion were aspirated to identify the above microbes before operation and within 1 week of ending of menstrual bleeding for 4 consecutive postoperative cycles. Bacteria-carrier was defined as at least one of the 5 microbes detected.

RESULTS

No difference was shown in the incidence of bacteria-carrier (IBC) among the 4 groups preoperation. The IBC tended to be the highest in the first menstrual cycle postsurgery in all the 4 groups, then decreased. Compared with preoperation, there were significantly higher IBC in the 3 IUD groups (P < 0.05) except group 1.

CONCLUSION

IUD is a major factor for intrauterine microbes existing after operation, and the natural body defense system can help to get rid of the organism by time. Small doses and short period of penicillin or lincomycin administration proved not effective in clearing the intrauterine microbes after IUD insertion.

[Fate of massive retrieved human bone allografts]

OBJECTIVES

To study retrieved massive human allograft specimen after they had been in situ for four to sixty-five months, and to investigate the changes union, bone replacement and degradation of articular cartilage.

METHOD

BMP gene expression in the specimen was also studied with in situ hybridization, immunohistochemical methods, and the observations were correlated with the clinical and isotope scan date.

RESULT

The union between the allograft and the host was achieved by the formation of an external callus derived from the cortex of the host. New bone replacement took place slowly. Analysis of the articular cartilage revealed evidence that some chondrocytes had survived in non bearing area of the articular. The expression of BMP in the surface of the cortex and united callus was positive 4 months after implantation. But it was negative in the center of cortex after it had been implanted for over 12 months. An external callus formed from the cortex of the host. Some chondrocytes survived in non-bearing area of the articular. Neovasculature penetrated into osteoarticular.

CONCLUSION

Bone absorption may be the cause of collapse of articular surface. The results suggest that large allografts in humans are osteo-conductive rather than inductive. Incomplete repair of osteon may be related to slowed replacement of massive human allograft.

[Effects of tea polyphenol on blood lipid and antioxidation in vivo in aged rats]

OBJECTIVE

To study the ability of tea polyphenol to lowering blood lipid and antioxidation in the aged rats.

METHODS

The SD rats were divided into three groups, i.e., control group and two trial groups fed with 1% and 2% tea polyphenol for six weeks, respectively.

RESULTS

Tea polyphenol could reduce serum level of lipid peroxide and increase the ratio of high-density lipoprotein cholesterol (HDL-C) to total cholesterol (TC), and significantly lower serum level of lipid peroxide in rats. Activities of superoxide dismutase in red blood cells of rats fed with 2% tea polyphenol were significantly higher than those in control ones.

CONCLUSION

Tea polyphenol can enhance antioxidation in vivo in the aged rats.

[Effects of different vascular beds on the microstructural components and intimal hyperplasia of autogenous vein grafts in dogs]

In order to investigate the effect of vascular beds on the vascular wall of autogenously grafted vein, femoral veins were reversely placed in between the cut ends of collateral femoral arteries in 11 dogs with atraumatic technique. The grafted veins were covered with vivid muscle or skin respectively after being assured to be patent, and investigated by histomorphologic method and computerized image analysis technique at postoperative intervals of 1 week, 4 weeks and 16 weeks. The results showed that: 1. One graft developed pseudoaneurysm at 1 week, and two grafts were occulded in skin-covered group, whereas, no complications occurred in muscle-covered group. 2. Intimal thickening of grafts in skin-covered group was much more obvious than that in the muscle-covered group (P < 0.05). 3. The relative contents of microstructural components of the graft wall showed no significant difference quantitatively between the two groups. So, the conclusion was: 1. Subcutaneous transplantation appeared to be a potential causative factor in inducing short-term excessive dilatation and long-term intimal hyperplasia of vein graft. 2. Muscular covering is of priority in blood vessel graft.

Tissue-specific expression of herpes simplex virus thymidine kinase gene delivered by adeno-associated virus inhibits the growth of human hepatocellular carcinoma in athymic mice

About 70% of hepatocellular carcinomas are known to express alpha-fetoprotein, which is normally expressed in fetal but not in adult livers. To induce herpes simplex virus-thymidine kinase expression in these cancer cells, we constructed an adeno-associated viral vector containing the HSV-TK gene under the control of the alpha-fetoprotein enhancer and albumin promoter. We previously demonstrated in vitro that although this vector can transduce a variety of human cells, only transduced AFP and albumin-expressing hepatocellular carcinoma cell lines were sensitive to killing by ganciclovir (GCV). In the present study, we explored the effect of this vector on hepatocellular carcinoma cells in vivo. Subcutaneous tumors generated in nude mice by implanting hepatocellular carcinoma cells previously transduced with this vector shrank dramatically after treatment with GCV. Bystander effect was also observed on the tumors generated by mixing transduced and untransduced cells. To test whether the tumor cells can be transduced by the virus in vivo, we injected the recombinant adeno-associated virus into tumors generated by untransduced hepatocarcinoma cell line. Tumor growth were retarded after treatment with GCV. These experiments demonstrate the feasibility of in vivo transduction of tumor cell with rAAV.

Elevation of an endogenous inhibitor of nitric oxide synthase in diabetic rat serum

AIM

To study the endogenous inhibitor of NO synthase NG,NG-dimethyl-arginine (DMA) in the diabetic rat serum.

METHODS

In streptozocin-induced diabetic rats, the serum DMA level and endothelium-dependent vasorelaxation to acetylcholine (ACh) were determined.

RESULTS

The serum DMA concentration was increased in the diabetic rats compared with their age-matched controls (5.4 +/- 1.0 vs 0.7 +/- 0.3 mumol.L-1, P < 0.01). The serum malondialdehyde (MDA) level was also increased in the diabetic rats compared with controls (2.5 +/- 0.3 vs 1.5 +/- 0.1 mumol.L-1, P < 0.01). Vasodilator response to ACh was impaired in diabetic thoracic aortas, which was improved by preincubation with L-arginine 1 mmol.L-1.

CONCLUSION

Hyperglycemia elevated the endogenous DMA content, which contributed to attenuated endothelium-dependent vasorelaxation in streptozocin-induced diabetic rats.

Failure of a second X-ray dose to activate nuclear factor kappaB in normal rat astrocytes

Induced gene expression and subsequent cytokine production have been implicated in the normal tissue injury response to radiotherapy. However, studies of radiation-induced gene expression have used single radiation doses rather than the fractionated exposures typical of the clinical situation. To study the effects of multiple radiation doses on gene expression, we investigated nuclear factor kappaB (NFkappaB) DNA binding activity in primary astrocyte cultures after one and two exposures to x-rays. After a single dose of x-rays (3.8-15 gray (Gy)), NFkappaB binding activity in astrocytes increased in a dose-dependent manner, reaching a maximum by 2-4 h and returning to control levels by 8 h after irradiation. In split-dose experiments, when an interval of 24 h was used between two doses of 7.5 Gy, the second 7.5-Gy exposure failed to induce NFkappaB activation. The period of desensitization induced by the first radiation exposure was dose-dependent, persisting approximately 72 h after 7.5 Gy compared with 24 h after 1.5 Gy. No changes in IkappaBalpha protein levels were detected. However, the presence of a transcription inhibitor prevented the desensitizing effect of the initial irradiation. Irradiation also prevented NFkappaB activation in astrocytes by a subsequent exposure to H2O2, but it had no effect on the activation induced by tumor necrosis factor-alpha. These data indicate that an initial x-ray exposure can desensitize astrocytes to the NFkappaB-activating effects of a subsequent radiation exposure. Furthermore, they suggest that this desensitization depends on gene transcription and may have some specificity for NFkappaB activation mediated by reactive oxygen species.

The critical active-site amine of the human 8-oxoguanine DNA glycosylase, hOgg1: direct identification, ablation and chemical reconstitution

BACKGROUND

Base-excision DNA repair (BER) is the principal pathway responsible for the removal of aberrant, genotoxic bases from the genome and restoration of the original sequence. Key components of the BER pathway are DNA glycosylases, enzymes that recognize aberrant bases in the genome and catalyze their expulsion. One major class of such enzymes, glycosylase/lyases, also catalyze scission of the DNA backbone following base expulsion. Recent studies indicate that the glycosylase and lyase functions of these enzymes are mechanistically unified through a common amine-bearing residue on the enzyme, which acts as both the electrophile that displaces the aberrant base and an electron sink that facilitates DNA strand scission through imine (Schiff base)/conjugate elimination chemistry. The identity of this critical amine-bearing residue has not been rigorously established for any member of a superfamily of BER glycosylase/lyases.

RESULTS

Here, we report the identification of the active-site amine of the human 8-oxoguanine DNA glycosylase (hOgg1), a human BER superfamily protein that repairs the mutagenic 8-oxoguanine lesion in DNA. We employed Edman sequencing of an active-site peptide irreversibly linked to substrate DNA to identify directly the active-site amine of hOgg1 as the epsilon-NH2 group of Lys249. In addition, we observed that the repair-inactive but recognition-competent Cys249 mutant (Lys249-->Cys) of hOgg1 can be functionally rescued by alkylation with 2-bromoethylamine, which functionally replaces the lysine residue by generating a gamma-thia-lysine.

CONCLUSIONS

This study provides the first direct identification of the active-site amine for any DNA glycosylase/lyase belonging to the BER superfamily, members of which are characterized by the presence of a helix-hairpin-helix-Gly/Pro-Asp active-site motif. The critical lysine residue identified here is conserved in all members of the BER superfamily that exhibit robust glycosylase/lyase activity. The ability to trigger the catalytic activity of the Lys249-->Cys mutant of hOgg1 by treatment with the chemical inducer 2-bromoethylamine may permit snapshots to be taken of the enzyme acting on its substrate and could represent a novel strategy for conditional activation of catalysis by hOgg1 in cells.

Effect of calcitonin gene-related peptide-induced preconditioning on attenuated endothelium-dependent vasorelaxation induced by lysophosphatidylcholine

AIM

To study the effects of calcitonin gene-related peptide (CGRP)-induced preconditioning on the inhibition of endothelium-dependent vasorelaxation to acetylcholine (ACh) by lysophosphatidylcholine (Lys) in the isolated rabbit and rat thoracic aortas.

METHODS

Endothelium-dependent relaxation to ACh was studied in the aortic rings precontracted with phenylephrine 0.1 mumol.L-1 in the absence or presence of Lys.

RESULTS

On the rabbit aortic rings, Lys 5 mg.L-1 impaired vasodilator responses to ACh. Pretreatment with CGRP 0.1 mumol.L-1 for 5 min attenuated the inhibition of vasodilator responses to ACh by Lys. The effect of CGRP was blocked by 1-(5-isoquinolinysulfonyl)-2-methylpiperazine (H-7), an inhibitor of protein kinase C (PKC) (% relaxations to ACh 1 mumol.L-1 were 88 +/- 4, 28 +/- 10, 65 +/- 13, and 25 +/- 10 for control, Lys, Lys + CGRP, and Lys + CGRP + H-7, respectively). The same effects of CGRP were shown in the rat aortic rings, and the effect of CGRP was also abolished by H-7 (% relaxations to ACh 1 mumol.L-1 was 84 +/- 10, 55 +/- 11, 76 +/- 11, and 50 +/- 14 for control, Lys, Lys + CGRP, and Lys + CGRP + H-7, respectively).

CONCLUSION

CGRP-induced preconditioning protected the endothelium against injury elicited by Lys, the effect of CGRP is related to the activation of PKC.

Luman, a new member of the CREB/ATF family, binds to herpes simplex virus VP16-associated host cellular factor

The human host cell factor (HCF) is expressed in a variety of adult and fetal tissues, and its gene is conserved in animals as diverse as mammals and insects. However, its only known function is to stabilize the herpes simplex virus virion transactivator VP16 in a complex with the cellular POU domain protein Oct-1 and cis-acting regulatory elements in promoters of immediate-early viral genes. To identify a cellular function for HCF, we used the yeast two-hybrid system to identify a cellular ligand for HCF. This protein, Luman, appears to be a cyclic AMP response element (CRE)-binding protein/activating transcription factor 1 protein of the basic leucine zipper superfamily. It binds CREs in vitro and activates CRE-containing promoters when transfected into COS7 cells. This activation of transcription was synergistically enhanced by the presence of CCAAT/enhancer-binding protein elements and inhibited by AP-1 elements in the promoter. In addition to a basic DNA binding domain, Luman possesses an unusually long leucine zipper and an acidic amino-terminal activation domain. These features in Luman are also present in what appear to be homologs in the mouse, Drosophila melanogaster, and Caenorhabditis elegans. Luman and VP16 appear to have similar mechanisms for binding HCF, as in vitro each competitively inhibited the binding of the other to HCF. In transfected cells, however, while VP16 strongly inhibited the ability of GAL-Luman to activate transcription from a GAL4 upstream activation sequence-containing promoter, Luman was unable to inhibit the activity of GAL-VP16. Luman appears to be a ubiquitous transcription factor, and its mRNA was detected in all human adult and fetal tissues examined. The possible role of HCF in regulating the function of this ubiquitous transcription factor is discussed.

Protection by capsaicin against attenuated endothelium-dependent vasorelaxation due to lysophosphatidylcholine

Previous studies have shown that pretreatment with calcitonin gene-related peptide (CGRP), a principal transmitter in sensory nerves, can protect the endothelial cell. We therefore evaluated whether in vivo capsaicin treatment prevents endothelial damage elicited by lysophosphatidylcholine (LPC) in the rat aorta. Acute treatment or repeated pretreatment with capsaicin resulted in stimulation of neurotransmitter release from sensory nerves or depletion of their transmitter content respectively. Vasodilator responses to acetylcholine (ACh) were examined in the aorta of these animals. Acute application of capsaicin (50 mg/kg) increased the plasma concentration of CGRP-like immunoreactivity (CGRP-LI) concomitantly with a reversal of the inhibition by LPC of endothelium-dependent ACh-induced relaxation in the isolated rat aorta. After repeated pretreatment with capsaicin to deplete sensory nerve neurotransmitter content the effects of capsaicin were absent as shown by the plasma CGRP-LI concentration and the vasodilator response to ACh. The results demonstrate that systemic capsaicin treatment, which evokes the release of CGRP from sensory nerves, protects the endothelial cell. The present study also suggests that CGRP may be an endogenous vascular protective substance.

Determination of Association Constants for Cyclodextrin-Surfactant Inclusion Complexes: A Numerical Method Based on Surface Tension Measurements

Inclusion complexes of beta-cyclodextrin (beta-CD) with sodium octyl sulfonate (C8As), sodium dodecyl sulfonate (C12As), and sodium hexadecyl sulfonate (C16As) in aqueous solutions are studied by surface tension measurement at the air/water interface at different temperatures. At fixed concentrations of the surfactants, the surface tension increases with an increase in beta-CD concentration to a maximum value, at which it holds. The surface tension curves of the surfactants in the presence of beta-CD are higher than those in the absence of beta-CD. The curves rise higher with the increase in beta-CD concentration for each surfactant. The apparent critical micelle concentrations (CMC*) of the surfactants vary linearly with beta-CD concentration. The CMC* and surface tension values (including those after the CMC*) for the same system decrease with increase in temperature. A numerical method based on surface tension measurements is developed to determine the association constants for 1:1 inclusion complexes. This method is very reliable and easy to perform. The results demonstrate that the longer the hydrophobic tail of the surfactant, the greater the association constant with beta-CD, and that for the same surfactant the association constant is higher at lower temperatures.

[Identification of herba hedyotis diffusae and its confused material Herba Hedyotis pinifoliae]

This article has reported the results of the study on the outer properties, inter organization and TLC of Herba Hedyotis Diffuse and its confused material Herba Hedyotis Pinifoliae. The results show the two have obvious distinction and can not be confusediy used.

A mammalian DNA repair enzyme that excises oxidatively damaged guanines maps to a locus frequently lost in lung cancer

BACKGROUND

Guanine residues in the genome are vulnerable to attack by free radicals and reactive oxygen species. A major lesion thus produced, 8-oxoguanine (OG), causes mutations by mis-pairing with adenine during replication. In bacteria and budding yeast, OG is removed from the genome through the action of base-excision DNA repair (BER) enzymes, which catalyze expulsion of the aberrant base and excision of its sugar moiety from the DNA backbone. Although OG is known to be produced in and cleansed from mammalian genomes, the enzymes responsible for OG repair in these cells have remained elusive.

RESULTS

Here, we report the cloning and biochemical characterization of mammalian BER enzymes that specifically target OG residues in DNA. These 8-oxoguanine DNA glycosylases, hOgg1 (human) and mOgg1 (murine), are homologous to each other and to yeast Ogg1. They also contain an active site motif - the Helix-hairpin-Helix, Gly/Pro-rich-Asp motif - characteristic of a superfamily of BER proteins with a similar core fold and active site geometry. Both hOgg1 and mOgg1 exhibit exquisite selectivity for the base opposite OG in DNA, operating with high efficiency only on OG base-paired to cytosine. Furthermore, hOgg1 and mOgg1 are unable to process a panel of alternative lesions, including 8-oxoadenine, yet bind with high affinity to synthetic abasic site analogs. The proteins operate through a classical glycosylase/lyase catalytic mechanism; mutation of a catalytically essential lysine residue results in loss of catalytic potency but retention of binding to OG-containing oligonucleotides. The hOGG1 gene is localized on the short arm of chromosome 3 (3p25/26) in a region commonly deleted in cancers.

CONCLUSIONS

These results conclusively establish the existence and identity of an 8-oxoguanine DNA glycosylase/lyase in human and murine cells, completing the triad of proteins that together protect mammals from the genotoxic effects of guanine oxidation. The observation that at least one allele of hOGG1 is commonly deleted in cancer cells suggests that such cells may possess a reduced capacity to counter the mutagenic effects of reactive oxygen species, a deficiency that could increase their overall genomic instability. This speculation is fueled by recent observations that cells constitutively active for the Ras/Raf pathway constitutively produce high levels of superoxide, a known generator of OG.

[Pharmacological study on the compatibility of cortex Cinnamomi with Halloysitum Rubrum]

The decoction of Cortex Cinnamomi (CC, 1 g/kg p.o.) and Halloysitum Rubrum (HR, 3 g/kg p.o.) or the combination of the two drugs (4 g/kg p.o., CC 1 g/kg, HR 3 g/kg) could antagonize the diarrhea caused by p.o. water ex tract of Radix et Rhizoma Rhei in mice; and inhibit the platelet aggregation induced by ADP in vitro. Meanwhile, the effect of the combination of the two drugs was not different from that of each single one. In addition, CC was able to inhibit the spontaneous movement of intestine in situ and showed an analgesic effect (hot-plate method) in mice; HR was ineffective in these aspects and did not reduce the effect of CC. CC(20 g/kg p.o., i.p. or i.v.) exhibited very strong toxicity in mice, while HR(60 g/kg p.o., i.p. or i.v.) was nontoxic. When the two drugs were used together, the toxicity was markedly reduced.

[Studies on biological effects of kappa-selenocarrageenan on human breast cancer cell line BCaP-37]

Proliferation, cell cycle, total amount of DNA, area of cell nucleus, as well as epidermal growth factor receptors (EGFR) and expression of oncogene C-erbB2 mRNA of Chinese breast cancer cell line (BCaP-37) after being treated with kappa-selenocarrageenan were determined by cell culture technique, image cytometry (ICM) and northern blot to explore its anti-tumor mechanism. Results revealed 3.0-120 mg/L selenocarrageenan could inhibit proliferation of BCaP-37, with a response of time and dose dependence. The areas of nuclei were significantly lower with ICM in cells treated with 15 or 60 mg/L selenocarrageenan for four days than those in controls (P < 0.01). Levels of EGFR and expression of C-erbB2 mRNA were significantly inhibited in cells treated with 60 mg/L selenocarrageenan. It suggests that selenocarrageenan can inhibit proliferation of breast cancer cells through regulation of the levels of EGFR and expression of C-erbB2 mRNA.

Leptin treatment rescues the sterility of genetically obese ob/ob males

Leptin, a hormone secreted from white adipose tissue, has been shown to normalize the body weight of ob/ob but not db/db mice as postulated by Coleman in his classical parabiosis experiments. The major effect of leptin is therefore to decrease food intake, thus resulting in a breakdown of fat stores. Recently, we have suggested that leptin plays a role in reproductive physiology based on the observation that leptin treatment but not food restriction rescues the sterility of ob/ob females. In the present communication, we treated sterile ob/ob males with leptin and asked whether fertility could be induced, thus selecting their reproductive ability as the endpoint of the experiment. Our results show that all food-restricted ob/ob males are unable to impregnate normal C57BL/6J females. However, all leptin-treated ob/ob males fertilized normal females mice that carried out normal pregnancies and deliveries, demonstrating that the reproductive capacity of ob/ob males was corrected only with leptin treatment. Furthermore, reproductive indices such as testicular weight and histology are normalized in leptin-treated animals. Therefore, as in ob/ob females, leptin plays a significant role in the male mouse reproductive pathways.

The prostaglandin transporter is widely expressed in ocular tissues

Prostaglandins (PGs) play important physiological and therapeutic roles in the eye. Our laboratory recently identified a novel PG transporter in the rat that we call "PGT" (Science 268:866, 1995). We have also recently cloned the human PGT cDNA (J Clin Invest 98:1142, 1996). To determine whether PGT might play a role in human ocular tissues, we performed Northern blot analysis of RNA obtained from human ocular tissues and from the nonpigmented ciliary epithelium cell line "ODM-2." PGT transcripts were clearly evident in all ocular tissues. Given that the functional profile of PGT expressed in vitro strongly suggests a role in PG uptake and degradation, the present results suggest that PGT may function in various regions of the human eye for purposes of terminating the signal(s) produced by locally-synthesized PGs.

Early onset of reproductive function in normal female mice treated with leptin

Numerous studies have revealed an association between nutritional status, adiposity, and reproductive maturity. The role of leptin, a hormone secreted from adipose tissue, in the onset of reproductive function was investigated. Normal prepubertal female mice injected with leptin grew at a slower rate than controls as a result of the hormone's thinning effects, but they reproduced up to 9 days earlier than controls and showed earlier maturation of the reproductive tract. These results suggest that leptin acts as a signal triggering puberty, thus supporting the hypothesis that fat accumulation enhances maturation of the reproductive tract.

[Influence of low energy He-Ne laser on regeneration of peripheral nerve]

The purpose of this experiment was to elucidate the influence of the low-energy He-Ne laser on the function of regeneration of peripheral nerve. Forty-four rabbits about 2.5 kg body weight were used in the experiment. The animals were divided into 4, 8, 12, 16 weeks groups according to the observation period. Six animals were used in each irradiated group and in the control group 5 rabbits were used in each observation period. Regeneration of the axon and myelinc sheath, the latent rate of the common peroneal nerve, the conditions of the anterior tibital muscle and the toe expansion test were all observed systematically in both groups. The experimental results was: A few thin regenerated axon was seen at 4 weeks in the irradiated group, while in the control group it might be seen at 8 weeks, the P value was < 0.01. A low amplitude latent rate of the common peroneal nerve is determined at the peroneal side of the anterior tibial muscle in a few animal at 4 weeks of the irradiated group, and it is not observed in the control group, from 12 to 16 weeks. THe latent rate of the common peroneal nerve was the irradiated group than in the controlled, the P value was < 0.01. The regeneration of the myeline sheath was evident in the irradiated group, and also the slstion of the musdle fibers anterior tibial muscle was clearly visible than the controlled. 16 weeks postoperatively, the toe expansion test was normal in the irradiated group, while in the control group it was the same as seen at 12 weeks after operation in the irradiated group. Now it was certain that the low-energy He-Ne laser could promole the function of the spinal motor nerve cells and accelerate the axonal regeneration.

[Influence of low energy He-Ne laser on spinal motor nerve cell]

The object of this experimental study was to investigate the influence of low-energy He-Ne laser on the motor nerve cells of the spinal cord. The experimental study included as follws: (1) Four rabbits were used in this experiment. The L5-6 spinal cord segment was irradiated by He-Ne laser percutaneously, the nerve velocity of the comon peroneal nerve was measured in order to determine the function of the spinal motor nerve cells when the peripheral nerve was intact. (2) The common peroneal nerve was transected on one side wothout repair, two weeks after laser irradiation, the grey mater of the spinal cord of L5-6 segment was procured for electronic microscopic examination. (3) The common peroneal nerve on the contralateral side was transected and followed by end-to-end anastomosis, and laser irradiation was done on the same spinal cord segment. Two weeks after irradiation, the nerve velocity of the common peroneal nerve and the toe expanding test were investigated. The results were: (1) the He-Ne laser can influence the spinal motor nerve cells function as expressed by latent rate when the peripherial nerve is intact. i.e. the nerve velocity is slower than mormal, and the amplitude is markedly decreared. (2) the change of the microstructure of the spinal motor nerve cells is comparatively slight in the 10 and 15 minutes groups. (3) the recovery of the nerve velocity and the toe expansion are more earlier in the 15 min. group. In short, the low-energy He-Ne laser can influence the function of the spinal motor nerve cells.

NRF2, a member of the NFE2 family of transcription factors, is not essential for murine erythropoiesis, growth, and development

The locus control region of the beta-globin gene is composed of four erythroid-specific hypersensitive sites. Hypersensitive site 2 has been shown to be a powerful enhancer and contains a tandem repeat sequence for the transcription factors AP1 and NFE2 (activating protein 1 and nuclear factor erythroid 2, respectively). The human NRF2 (NFE2 related factor 2) has been isolated by bacterial expression screening using this core sequence as a probe. p45-NFE2, NRF1, and NRF2 belong to the CNC ("cap 'n' collar") subfamily of the basic region-leucine zipper transcription factors, which exhibits strong homology at specific regions such as the "CNC" and the DNA binding and leucine zipper domains. Although the erythroid-specific p45-NFE2 has been implicated in globin gene regulation, p45-NFE2 null mice succumb to bleedings due to lack of platelets and those that survive exhibit only a mild anemia. To determine the function of NRF2, which we found to be widely expressed in vivo, we have characterized the genomic structure of the mouse NRF2 gene, disrupted the Nrf2 gene by homologous recombination in mouse embryonic stem cells (ES cells), and generated NRF2-/- mice. Homozygous mutant mice developed normally, were not anemic, reached adulthood, and reproduced. Our studies indicate that NRF2 is dispensable for mouse development.