Activation of PPARgamma coactivator-1 through transcription factor docking

Transcriptional coactivators have been viewed as constitutively active components, using transcription factors mainly to localize their functions. Here, it is shown that PPARgamma coactivator-1 (PGC-1) promotes transcription through the assembly of a complex that includes the histone acetyltransferases steroid receptor coactivator-1 (SRC-1) and CREB binding protein (CBP)/p300. PGC-1 has a low inherent transcriptional activity when it is not bound to a transcription factor. The docking of PGC-1 to peroxisome proliferator-activated receptor gamma (PPARgamma) stimulates an apparent conformational change in PGC-1 that permits binding of SRC-1 and CBP/p300, resulting in a large increase in transcriptional activity. Thus, transcription factor docking switches on the activity of a coactivator protein.

Occult metastases in the sentinel lymph nodes of patients with early stage breast carcinoma: A preliminary study

BACKGROUND

Thirty percent of lymph node negative patients with operable breast carcinoma experience disease recurrence within 10 years. Retrospective serial sectioning of axillary lymph nodes has revealed undetected metastases in 9-30% of these patients. These occult metastases have been shown to have an adverse effect on survival. Serial sectioning (SS) is impractical for all axillary lymph nodes harvested from Levels I and II, but it is feasible if applied only to sentinel lymph nodes.

METHODS

Sentinel lymph nodes from 52 patients with invasive breast carcinoma were cut at 2 mm intervals, fixed in 10% formalin, and embedded in paraffin. Sections were taken from the blocks, stained with hematoxylin and eosin (H & E), and compared with cytokeratin-stained sections taken at 0.25 mm intervals throughout the entire blocks.

RESULTS

Tumor metastases were found in 6 patients (12%) when the sentinel lymph nodes were sectioned at 2 mm intervals and stained with H & E, compared with 30 patients (58%) when the same lymph nodes were serially sectioned at 0.25 mm intervals and stained with cytokeratin. Of 24 patients whose metastases were detected by SS and cytokeratin staining, 12 had isolated tumor cells and 12 had colonies of several thousand malignant cells.

CONCLUSIONS

Routine histologic examination of axillary lymph nodes, including sentinel lymph nodes, in cases of breast carcinoma significantly underestimates lymph node metastases. This deficiency may be overcome by SS of the entire lymph nodes and staining with a specific monoclonal antibody. The percentage of patients found to have colonies of cells that were missed by routine sectioning corresponds closely to the percentage of "lymph node negative" patients who would be expected to relapse. The true clinical significance of these occult metastases will be determined by long term follow-up. [See editorial on pages 905-7, this issue.]

The effect of patient-specific factors on radiation-induced regional lung injury

PURPOSE

To assess the impact of patient-specific factors on radiation (RT)-induced reductions in regional lung perfusion.

METHODS

Fifty patients (32 lung carcinoma, 7 Hodgkin's disease, 9 breast carcinoma and 2 other thoracic tumors) had pre-RT and > or = 24-week post-RT single photon emission computed tomography (SPECT) perfusion images to assess the dose dependence of RT-induced reductions in regional lung perfusion. The SPECT data were analyzed using a normalized and non-normalized approach. Furthermore, two different mathematical methods were used to assess the impact of patient-specific factors on the dose-response curve (DRC). First, DRCs for different patient subgroups were generated and compared. Second, in a more formal statistical approach, individual DRCs for regional lung injury for each patient were fit to a linear-quadratic model (reduction = coefficient 1 x dose + coefficient 2 x dose2). Multiple patient-specific factors including tobacco history, pre-RT diffusion capacity to carbon monoxide (DLCO), transforming growth factor-beta (TGF-beta), chemotherapy exposure, disease type, and mean lung dose were explored in a multivariate analysis to assess their impact on the coefficients.

RESULTS

None of the variables tested had a consistent impact on the radiation sensitivity of regional lung (i.e., the slope of the DRC). In the formal statistical analysis, there was a suggestion of a slight increase in radiation sensitivity in the dose range >40 Gy for nonsmokers (vs. smokers) and in those receiving chemotherapy (vs. no chemotherapy). However, this finding was very dependent on the specific statistical and normalization method used.

CONCLUSION

Patient-specific factors do not have a dramatic effect on RT-induced reduction in regional lung perfusion. Additional studies are underway to better clarify this issue. We continue to postulate that patient-specific factors will impact on how the summation of regional injury translates into whole organ injury. Refinements in our methods to generate and compare SPECT scans are needed.

Molecular and idiotypic analyses of the antibody response to Cryptococcus neoformans glucuronoxylomannan-protein conjugate vaccine in autoimmune and nonautoimmune mice

The antibody response to Cryptococcus neoformans capsular glucuronoxylomannan (GXM) in BALB/c mice frequently expresses the 2H1 idiotype (Id) and is restricted in variable gene usage. This study examined the immunogenicity of GXM-protein conjugates, V (variable)-region usage, and 2H1 Id expression in seven mouse strains: BALB/c, C57BL/6, A/J, C3H, NZB, NZW, and (NZB x NZW)F(1) (NZB/W). All mouse strains responded to vaccination with GXM conjugated to tetanus toxoid (TT), the relative magnitude of the antibody response being BALB/c approximately C3H > C57BL/6 approximately NZB approximately NZW approximately NZB/W > A/J. Analysis of serum antibody responses to GXM with polyclonal and monoclonal antibodies to the 2H1 Id revealed significant inter- and intrastrain differences in idiotype expression. Thirteen monoclonal antibodies (MAbs) (two immunoglobulin M [IgM], three IgG3, one IgG1, three IgG2a, two IgG2b, and two IgA) to GXM were generated from one NZB/W mouse and one C3H/He mouse. The MAbs from the NZB/W mouse were all 2H1 Id positive (Id(+)) and structurally similar to those previously generated in BALB/c mice, including the usage of a V(H) from the 7183 family and Vkappa5.1. Administration of both 2H1 Id(+) and Id(-) MAbs from NZB/W and C3H/H3 mice prolonged survival in a mouse model of cryptococcosis. Our results demonstrate (i) that V-region restriction as indicated by the 2H1 Id is a feature of both primary and secondary responses of several mouse strains; and (ii) that there is conservation of V-region usage and length of the third complementarity-determining region in antibodies from three mouse strains. The results suggest that V-region restriction is a result of antibody structural requirements necessary for binding an immunodominant antigen in GXM.

[Effects of monoclonal antibody against the major cell surface protein on salivary agglutinin mediated aggregation of Streptococcus sobrinus]

OBJECTIVE

To investigate the effects of monoclonal antibody on salivary agglutinin-mediated aggregation of Streptococcus sobrinus in vitro.

METHODS

Bacterial aggregation inhibition was measured under OD650 at 10 minutes intervals for 1 hour.

RESULTS

It showed that the McAb ZS2/286 raised against the PAg of S. sobrinus 6715 could inhibit the aggregation by some degree, but the effect was not significant.

CONCLUSION

The McAb ZS2/286 might not bind directly to the functionally important region of PAg related to aggregation.

Existence and global attractivity of positive periodic solutions of periodic n-species Lotka-Volterra competition systems with several deviating arguments

In this paper, we study the existence and global attractivity of positive periodic solutions of periodic n-species Lotka-Volterra competition systems. By using the method of coincidence degree and Lyapunov functional, a set of easily verifiable sufficient conditions are derived for the existence of at least one strictly positive (componentwise) periodic solution of periodic n-species Lotka-Volterra competition systems with several deviating arguments and the existence of a unique globally asymptotically stable periodic solution with strictly positive components of periodic n-species Lotka-Volterra competition system with several delays. Some new results are obtained. As an application, we also examine some special cases of the system we considered, which have been studied extensively in the literature. Some known results are improved and generalized.

[Apoptosis in the developing tooth of postnatal rat]

OBJECTIVE

To study apoptosis in the developing tooth of postnatal rat.

METHODS

Transferase-mediated, dUTP-biotin nick end labeling(TUNEL) method was utilized to label the paraffin sections of the lower and upper jaws taken from 3 days and 9 days of postnatal rats.

RESULTS

Positive stains for the presence of apoptosis were observed in ameloblasts, especially in cervical loop region, and stellate reticulum cells. Odontoblasts at the tip of developing molars in which physiological osteodentin was forming were strongly positive. A few dental pulp cells were labeled.

CONCLUSION

Apotosis is a biological process, which play an important role in the formation of teeth. Apoptosis may take place in epithelial derived cells as well as mesenchymal-derived cells.

Immunolabeling of the major cell surface protein antigen of Streptococcus sobrinus with monoclonal antibody

OBJECTIVE

The purpose of this study was to determine the accessibility of monoclonal antibody (McAb), specific for the major cell surface protein antigen (PAg) of Streptococcus sobrinus, to the surface of its native epitopes.

MATERIALS AND METHODS

An indirect immunogold labeling technique was used to detect the reaction of McAb with S. sobrinus 6715. The reactions of polyclonal antibodies (PcAbs) against S. sobrinus 6715 or PAg with S. sobrinus 6715, S. mutans Ingbritt C and S. rattus BHT were studied as controls.

RESULTS

The results indicated that PAg was localized on the outer cell surface of S. sobrinus, and McAb was reactive with only a few epitopes of the cell surface, whereas PcAbs were found to be reactive with more epitopes.

CONCLUSIONS

McAb was specific for the PAg, but there was cross-reaction with S. mutans. Also there seemed to be an association between the fuzzy coat on the surface of S. sobrinus and PAg.

[Effect of monoclonal antibody on the colonization of Streptococcus sobrinus and the development of dental caries in rats]

OBJECTIVE

To investigate the effect of local application of monoclonal antibody (McAb) raised against the major cell surface protein antigen of streptococcus sobrinus (PAg) on the colonization of rats' teeth by Streptococcus sobrinus (S. sobrinus) and the development of dental caries.

METHODS

30 wistar rats were divided into three groups: group I received McAb against PAg; group II received unrelated mice ascites; group III received PBS. They were applied on six occasions. After three times of application, streptomycin resistant S. sobrinus 6715 were inoculated onto the teeth and the rats were fed with caries-inducing diet 2000#. The number of colonized S. sobrinus were counted and the presence of caries was examined by the procedure of Keyes'.

RESULTS

There was a significant lower level of colonization by S. sobrinus and lower mean caries scores treated with McAb compared with the control groups.

CONCLUSION

Local passive immunization with McAb against PAg may be an effective way to prevent the colonization by implanted S. sobrinus and the development of dental caries.

Effects of monoclonal antibody on colonization of Streptococcus sobrinus and development of dental caries in rats

OBJECTIVE

To investigate the effect of local application of monoclonal antibody (McAb) raised against the 210KD cell surface protein antigen (PAg) of Streptococcus sobrinus on the colonization of rats' teeth and the development of dental caries.

MATERIALS AND METHODS

Thirty Wistar rats were divided into 3 groups: group 1 received McAb against PAg; group 2 received unrelated mice ascites; group 3 received pure buffered saline. The bacteria were applied 6 times to the occlusal surfaces of molars and to the labial surfaces of incisors. After three applications, streptomycin-resistant S. sobrinus 6715 was applied to the teeth and the rats were fed with caries-inducing diet 2000. The number of colonized S. sobrinus was counted on the streptomycin-supplemented mutans streptocci agar and expressed as a percentage of the total colonies on BHI agar. The presence of caries was examined and scored following Keyes' procedure.

RESULTS

There were significantly lower levels of colonization by S. sobrinus on rats' teeth and lower mean caries scores on the teeth treated with McAb compared with those in the control groups.

CONCLUSION

Local passive immunization with McAb against PAg may be an effective way to prevent colonization by implanted S. sobrinus and development of dental caries.

Inhibition of AP-1 and NF-kappaB by manganese-containing superoxide dismutase in human breast cancer cells

One of the primary antioxidant enzymes, manganese-containing superoxide dismutase (MnSOD), has shown the ability to reverse malignant phenotypes in a variety of human tumor cells that are low or absent in MnSOD expression. We have observed that overexpression of human MnSOD in human breast cancer MCF-7 cells inhibits tumor growth both in vitro and in vivo. The signaling pathway underlying the MnSOD induced tumor suppression is unknown. We demonstrate here that transcriptional and DNA binding ability of AP-1 and NF-kappaB, but not SP-1, were inhibited (by 50%) in the MCF-7 cell line overexpressing MnSOD. When transiently expressing, MnSOD inhibited AP-1 but increased NF-kappaB transactivation, which can be abolished by sodium pyruvate, a hydrogen peroxide scavenger. To analyze the target genes responsible for MnSOD-induced tumor suppression, genes related to tumor growth and responsive to AP-1 or NF-kappaB were analyzed. AP-1 responsive collagenase I, stromelysin I, and NF-kappaB responsive IL-1 and IL-6 were down-regulated in the MnSOD stable transfectants compared to the control cell lines. Since TPA induces differentiation in human breast cancer cells and up-regulates MnSOD gene in HeLa cells, MnSOD expression and AP-1 and NF-kappaB activity were measured under TPA treatment. The results showed that TPA induced endogenous MnSOD expression and inhibited both AP-1 and NF-kappaB. Together, these results suggest that tumor suppression by overexpressing MnSOD is related to a modulation of AP-1 and NF-kappaB, which causes a down-regulation of genes responsible for tumor malignant phenotype.

[The effect of retinoic acid on crown morphogenesis of mouse tooth germs in vitro]

OBJECTIVE

To study the effects of retinoic acid on crown morphogenesis of early tooth germs.

METHODS

Mouse tooth organ culture model was used and the functions of different retinoic acid concentration on the first mandibular molar germs of 14-day old mouse embryo were examined.

RESULTS

The first mandibular molar germ of 14-day old mouse was at the bud stage. After 6 days culture, tooth germs in culture medium (not containing retinoic acid) developed from bud stage to bell stage and formed normal cusps. The morphogenesis of tooth germs in medium containing 1 x 10(-7) mol/L retinoic acid was similar to molar germs in the medium without retinoic acid. When the concentration of retinoic acid increased to 1 x 10(-6) mol/L, the mouse tooth germs still developed from bud stage to bell stage, but normal cusps was not formed.

CONCLUSION

The results suggest that high concentration of retinoic acid alter crown morphogenesis of tooth germs.

Sentinel node biopsy in the staging of breast cancer

BACKGROUND

The role of axillary lymph node dissection (ALND) in breast cancer is currently being reevaluated. Sentinel node biopsy (SNB) holds promise for replacing full dissection in a large number of patients with breast cancer.

MATERIALS

We evaluated SNB utilizing an intraoperative gamma probe localization technique following injection of technetium sulfur colloid in 80 patients with primary breast cancer and clinically negative axillae. Forty-eight patients were evaluated at Baptist Medical Center, Montgomery, Alabama, and 32 at Rush-Presbyterian-St. Luke's Medical Center in Chicago, Illinois.

RESULTS

At least one sentinel node was found in 70 of the 80 patients (88%). One patient had a sentinel node in both the axilla and internal mammary chain. The remainder had axillary sentinel nodes only. The sentinel nodes accurately predicted the status of the axilla in 69 of the 70 patients (99%). One of 14 node-positive patients would have been missed with sentinel node biopsy alone, for a false negative rate of 7%. Four node-positive patients would have been missed with routine ALND without serial sectioning (SS) and immunohistochemical staining (IH) of the sentinel node.

CONCLUSIONS

Sentinel node biopsy with SS and IH more precisely predicted the status of the axilla than routine ALND in this group of patients. SNB will likely replace full axillary dissection in the majority of patients with breast cancer.

Optimal harvesting policy for single population with periodic coefficients

In this paper, we examine the exploitation of single population modeled by time-dependent Logistic equation with periodic coefficients. First, it is shown that the time-dependent periodic Logistic equation has a unique positive periodic solution, which is globally asymptotically stable for positive solutions, and we obtain its explicit representation. Further, we choose the maximum annual-sustainable yield as the management objective, and investigate the optimal harvesting policies for constant harvest and periodic harvest. The optimal harvest effort that maximizes the annual-sustainable yield, the corresponding optimal population level, the corresponding harvesting time-spectrum, and the maximum annual-sustainable yield are determined, and their explicit expressions are obtained in terms of the intrinsic growth rate and the carrying capacity of the considered population. Our interesting and brief results generalize the classical results of Clark for a population described by the autonomous logistic equation in renewable resources management.

[Cloning and sequence analysis of rOmpA gene fragment of spotted fever group Rickettsiae isolated in China]

Rr 190.70 p-602 n primers were used to amplify the rOmpA gene fragment of prototype strains (Rickettsia sibirica 246 strain and R. parkeri) and Chinese strains (BJ-90, Ha-91 and HLJ-054) of spotted fever group rickettsiae (SFGR). The PCR products were cloned into pGEM-T vector respectively and sequenced by Sanger's dideoxy method. The sequences of the tested strains were compared with the corresponding regions of prototype and reference strains of SFGR. The results showed that the homology of rOmpA gene fragments of prototype strains varied from 90.06%-96.62% in nucleotide and 83.05%-94.35% in putative amino acid respectively. Compared Chinese strains with prototype and reference strains of SFGR, it was found that the homology of BJ-90 strain and Ha-91 strain with R. sibirica 246 strain was the highest in nucleotide (99.06% and 98.31%, respectively) and in putative amino acid (98.87% and 96.61%, respectively), whereas HL-93 strain and HLJ-054 strain showed higher homology with R. japonica (96.62% and 95.68% in nucleotide, respectively) than others. Among all the Chinese strains, the homology between BJ-90 strain and Ha-91 strain was the highest, 99.25% in uncleotide and 97.74% in putative amino acid. The homology of nucleotide and putative amino acid between HL-93 strain and HLJ-054 strain was 98.12% and 94.92% respectively. The above results indicated that all SFGR so far isolated from different sources seem to be identical or closely related to R. sibirica, except for HL-93 and HLJ-054 strains, which could be considered as new members of SFGR.

Molecular pathogenesis of transplacentally induced mouse lung tumors

Previous studies from this and other laboratories have shown that treatment of pregnant mice with 3-methylcholanthrene (MC) caused lung tumors in the offspring, the incidence of which correlated with fetal inducibility of Cyp1a1. Analysis of paraffin-embedded lung tissue for Ki-ras-2 mutations indicated that 79% of the lesions examined contained point mutations in codons 12 and 13 of the Ki-ras-2 gene locus, the majority of which (84%) were G-->T transversions. The mutational spectrum was dependent on the tumor stage, as both the incidence of mutation and type of mutation produced correlated with malignant progression of the tumor. Mutations occurred in 60% of the hyperplasias, 80% of the adenomas, and 100% of the adenocarcinomas. In the tumors with mutations, GLY12-->CYS12 transversions occurred in 100% of the hyperplasias, 42% of the adenomas, and 14% of the adenocarcinomas. GLY12-->VAL12 transversions were not observed in hyperplasias and occurred in 42% of the adenomas and 57% of the adenocarcinomas. The remaining ASP12 and ARG13 mutations occurred only in adenomas (17%) and adenocarcinomas (29%). The tumors were also analyzed for alterations in the structure or function of the tumor suppressor genes Rb, p53, and Cdkn2a. No mutations were observed in exons 5-8 of the p53 gene. SSCP analysis demonstrated that 2 of 15 lung tumors contained shifted bands at the Cdkn2a gene locus. Sequence analysis had identified these as mutations in exon 2, with a CAC-->TAC transition at base 301 (HIS74-->TYR74) in tumor 23-1 and GGG-->GAG transition at base 350 (GLY90-->GLU90) in tumor 36-1. Northern blot analysis of the larger tumors revealed that 14 of 14 of these large lung tumors exhibited markedly decreased expression of Rb gene transcripts. These results were confirmed by immunohistochemistry. The larger tumors, which exhibited features of adenocarcinomas, showed a marked reduction or almost complete absence of nuclear pRb staining compared with smaller adenomas and normal lung tissue. The results suggest that Ki-ras-2 mutations are an early and frequent event in lung tumorigenesis, and that the type of mutation produced by environmental chemicals can influence the carcinogenic potential of the tumor. The results obtained with the Cdkn2a and Rb genes suggest that alterations in the Rb regulatory axis may play a key role in the pathogenesis of the pulmonary tumors and appear to occur later in the neoplastic process. It appears from these experiments that the combination of mutated Ki-ras-2 and alterations in the Rb regulatory gene locus, which are frequent alterations in human lung tumors, may be the preferred pathway for lung tumor pathogenesis in mice exposed transplacentally to environmental carcinogens.

[Cloning and expression of a gene associated with HL60 cell apoptosis induced by inhibition of polyamine biosynthesis]

OBJECTIVE

To clone the gene associated with apoptosis induced by an inhibitor of polyamine biosynthesis, alpha-difluoromethylomithine (DFMO).

METHODS

The differential substraction screening was used for gene cloning. The gene expression and apoptosis of transfected HL60 cells were detected by Northern blot, morphological assay, FCM and ladder map of DNA electrophoresis, respectively.

RESULTS

An apoptosis-associated gene named dF4 was cloned from HL60 cells treated with polyamine biosynthesis inhibitor. The programmed cell death was demonstrated in the HL60 cells transfected by dF4 gene.

CONCLUSION

dF4 gene cloned in this study could be a gene regulating apoptosis of HL60 cells.

Serial sectioning of sentinel nodes in patients with breast cancer: a pilot study

BACKGROUND

Recent reports indicate that the sentinel node, defined as the first regional lymph node to receive lymphatic fluid from the breast, accurately represents the metastatic status of the primary breast cancer. However, routine single section examination of the regional nodes, including the sentinel node, underestimates the true incidence of metastases. The goal of this study is to determine whether multiple sectioning of sentinel nodes will detect occult metastases in operable breast cancer.

METHODS

Nineteen patients with invasive breast cancers were injected with technetium-99m sulfur colloid solution around the tumor or at the biopsy site before lumpectomy and axillary lymph node dissection (ALND) or mastectomy. The labeled sentinel lymph nodes (SLND) were bivalved, and a central section was taken for hematoxylin and eosin (H & E) examination. The sentinel nodes of 13 patients, which were reported to be negative for metastases, were serially sectioned at 0.5-mm intervals and stained with H & E and a cytokeratin stain, CAM 5.2.

RESULTS

In the 13 node-negative patients, occult metastases were found in the sentinel nodes of 3 patients (23%). Two were seen on H & E and one by cytokeratin stain. The mean numbers of SLND and ALND in this series were 2.6 and 12.5, respectively, and the average number of sections for the two groups was 14 and 1, respectively.

CONCLUSION

Multiple sectioning of the sentinel node or nodes detects occult metastases and changes the staging of breast cancer.

[A study on anti-caries activity of genetic recombinant vaccine of Streptococcus lactis. II. Immunization in vein with recombinant S. lactis in pregnant rabbits]

The effects of immunization in vein with recombinant S. lactis HL107 carring the S. mutans surface protein PAc gene in pregnant rabbits were studied. The results indicated that specific anti-PAc IgG in serum and milk were obviously induced 1 week after immunization and retained at high level for several weeks. It suggests that the recombinant S. lactis HL107 possessing immunogenicity of S. mutans surface protein PAc is able to stimulate specific systemic immune response against PAc.

[The experimental study of immunization with purified surface protein antigen I/II from streptococcus mutans in BALB/c mice]

OBJECTIVE

To study the immunogenicity and immunoreactivity of purified surface protein antigen I/II from streptococcus mutans.

METHODS

Purified antigen I/II was used to immune BALB/c mice by subcutaneous injection route, and S. mutans whole cells were used as comparison.

RESULTS

ELISA showed immunization with antigen I/II highly induced both specific serum IgG antibody and specific salivary IgA antibody against antigen I/II (P < 0.01), but immunization with whole cells only induced specific serum IgG antibody (P < 0.05).

CONCLUSION

The study suggest purified antigen I/II is an effective candidate vaccine.

[Molecular cloning of a novel human lung cancer-associated antigen cDNA]

OBJECTIVE

To clone the gene of human lung cancer-associated antigen.

METHODS

The human lung squamous carcinoma cell line L-78 cDNA expression library was constructed with lambda gt 11 Sfi-Not directional cloning vector and screened with the anti-human lung cancer McAb ALT-04. The cDNA clone named hlc-14 was sequenced and further studied. NIH3T3 cells were transfected with the recombinant pXJ41-hlc14 plasmid, and the expression of hlc-14 cDNA was detected and characterized immunohistochemically. Soft agar colony formation assay of the transfectants was performed.

RESULTS

A human lung cancer lambda gt 11 cDNA library of 1.4 x 10(6) pfu/ml was constructed. Six cDNA clones were isolated following 4 rounds of immunoscreening. The largest cDNA clone hlc-14 contained 954 bp with no homology to any known gene when screened through GenBank. In the NIH3T3 cells transfectant of hlc-14 cDNA, the expression of the lung cancer-associated antigen was demonstrated. The ability of colony formation of the transfectant in the soft agar was enhanced.

CONCLUSION

The hlc-14 clone is a novel human lung cancer-associated antigen cDNA. It provides clues for the study of carcinogenesis mechanism of lung cancer and a novel target gene for the gene therapy of lung cancer.

Research on nucleolar organizer regions of hippocampal neuron in Alzheimer's disease

OBJECTIVE

To understand the cellular genetic expression of the cell's population by studying the nucleolar organizer regions (NORs) of hippocampal neuron of Alzheimer's disease (AD).

METHODS

The postmortem human hippocampal tissues were divided into three groups, namely, the young, the elderly and the AD groups. Each group contained tissues from 10 patients. The study was conducted using image pattern analysis of the nucleoli-nucleoplasms ratio of the neurons of Nissl's stained pathological cerebral hippocampal tissues, the area of stain, and the integrating absorption of nucleoli of silver-stained NORs.

RESULTS

The nucleoli-nucleoplasms ratio of the neurons of Nissl's stained cerebral hippocampal tissues, the area of stain, and the integrating absorption of the nucleoli of hippocampal neuron were decreased in the elderly and the AD groups as compared with the young group. However, the area of stain and the integrating absorption of the nucleoli of the hippocampal neurons were relatively increased in the AD group in comparison with the elderly group.

CONCLUSION

Nissl's stain demonstrates the hypofunction of the hippocampal neurons in the elderly and the AD patients. The Silver stain of NORs shows the decline of rDNA transcription activity of the nucleoli of the hippocampal neurons in the elderly and the AD patients. However, the transcription activity of the nucleoli of the hippocampal neurons of AD patients was relatively improved, and the cellular genetic expression of the cell's population was relatively strengthened. These cellular morphological changes have probably reflected the cellular defensive system.

[The different responses to anoxia in cultured CA1 and DG neurons from newborn rats]

Tissue culture from hippocampal CA1 or dentate gyrus (DG) region was established on the basis of previous neuronal culture technique. The viability, intracellular calcium concentration and brain-derived neurotrophic factor (BDNF) mRNA expression of the two kinds of neurons after anoxia were observed in the counting in the confocal microscopic field and in situ hybridization. It is found that DG neurons are not only more resistant to anoxia, but also have a stronger ability to keep calcium homeostasis and to express BDNF mRNA than CA1 neurons.

Over-expression of c-fos mRNA in the hippocampal neurons in Alzheimer's disease

OBJECTIVE

To analyze the relationship between the proto-oncogene c-fos change and neuronal degeneration in the hippocampus of the patients with Alzheimer's disease.

METHODS

The post mortem human hippocampal tissues were divided into three groups, namely, the aged, the young and Alzheimer's disease (AD) groups. Each group consisted of 10 patients. The diagnosis of AD was made by clinical manifestation and argentatine (Bodían) staining. Patients of both the young and the aged groups had no neurological disorders. The proto-oncogene c-fos mRNA was investigated in the hippocampal neurons using the method of in situ hybridization.

RESULTS

The optical density of stained area and the integral within proto-oncogene c-fos mRNA revealed a significant increase in the hippocampal neurons in cases of Alzheimer's disease as compared with the controls.

CONCLUSIONS

The over-expression of the proto-oncogene c-fos might play a role in the pathological process of Alzheimer's disease. These changes might result from a suffering stage of the hippocampal neurons or from a compensatory mechanism in the surviving neurons which are not yet affected-by the pathological process.

Comparison of CoMFA models for Salmonella typhimurium TA98, TA100, TA98 + S9 and TA100 + S9 mutagenicity of nitroaromatics

Comparative Molecular Field Analysis (CoMFA) was applied to a comprehensive data set of heterogeneous nitroaromatics tested in Salmonella typhimurium TA98 and TA100 with and without S9 microsomal activation. The four CoMFA models developed agree with postulated mechanisms of mutagenicity, and explain over 70% of the corresponding mutagenic variance The standard deviation coefficient contours common in the four models included high electronic density regions equivalent to C4-C5 in the pyrene ring, and an electron deficient site equivalent to C6. These areas are associated with high mutagenicity. Electron deficient areas may be related with the nitroreductive bioactivation of nitroaromatics. Electron rich sites may be involved with oxidative mechanisms analogous to the bioactivation pathway of polycyclic aromatic hydrocarbons. The contribution of steric factors to mutagenicity follows the order TA98 + S9 > TA98 > TA100 + S9 > TA100. The models indicated that increasing bulk perpendicular to the aromatic plane would decrease mutagenicity, but increasing the aromatic ring system along a region corresponding to C6-C7 in 1-nitropyrene would increase mutagenicity.

[Bianticollagen membrane: preparation and analysis of properties]

This study was undertaken to assess the antiplaque and anticollagenase properties of bianticollagen membrane (BACM) for use in the guided tissue regeneration (GTR). First, preparing cross-linked collagen membrane (GLCM) from bone collagen by glutaraldehyde and ultraviolet irradiation. Then, the GLCM was coated with tetracycline (TC) delivery device, which is BACM. BACM's properties are as follows: under scan electron microscope (SEM), it is a three dimensional structure with small pores; the modulus of elasticity in low strain regions and swelling ratio are 20.4 g/mm2 and 0.141 respectively; immediate type and delayed type hypersensitivity are negative; BACM with TC 150 micrograms placed into pockets, the average intrasulcular TC concentration measured at the end of the 7-days is 46.76 +/- 5.69 micromol/L, which is 2 times higher than MIC of TC; the period against collagenase (100 u) digestion is over 30 days in vitro; 1 mg GLCM and BACM implanted in mice may maintain about 4 weeks and 7 weeks respectively, and BACM and GLCM placed onto patient's root surface in flap operation and taken at 7th day the bacteria on BACM are significantly less than that on GLCM under SEM. These results indicate that BACM has antiplaque and stronger antidegradation effects than GLCM.

[Study on the vaccine against dental caries of recombinant Streptococcus lactis and artificial active immunization. V. Extraction, purification and dot blot analysis of RNA in the recombinant S. lactis]

To investigate the transcription level of the pac gene in the recombinant S. lactis, the amount of PAc-specific mRNA was measured by RNA dot blot analysis with the biotin-labeled 1.5 kb PstI fragment of the pac gene. RNA were extracted with guanidinium thiocyanate followed by centrifugation in cesium chloride solutions. These results indicated the sequence of PAc-mRNA in S. lactis HL107 or HL45 was the same as that in S. mutans Ingbritt and showed similar density photograph. The PAc-specific mRNA plated an intermediary role of protein synthesis in recombinant S. lactis and made it complete the expression of cloned pac gene.

Lymph node micrometastases from breast carcinoma: reviewing the dilemma

BACKGROUND

The presence or absence of regional lymph node metastases has been one of the most important determining factors in recommending adjuvant chemotherapy for patients with breast carcinoma. However, because of the 15-20% failure rate at 5 years for lymph node negative patients, other tumor-related prognostic factors have gained greater significance in this decision-making process. Many investigators have reported finding micrometastases that were not detected by routine sectioning of the lymph nodes but were identified by multiple sectioning and additional staining. This review attempts to evaluate the role of occult lymph node micrometastases and their relevance to disease recurrence.

METHODS

A literature search of the entire MEDLINE data base was conducted. All relevant articles were reviewed for the criteria they used to define micrometastases. The frequency of detection of micrometastases by various methodologies and the prognostic significance of such deposits were examined.

RESULTS

Tumor deposits involving the lymph nodes were found to be arbitrarily categorized as either micrometastases or macrometastases, with the cutoff point ranging from 0.2-2.0 mm. The detection rate of such deposits by conventional techniques was inadequate. Serial sectioning and immunohistochemistry appeared to increase the detection rate by 9-33%. A definite survival disadvantage was noted for patients with such occult metastases.

CONCLUSIONS

Current routine histologic examination of regional lymph nodes underestimates breast carcinoma metastases. Serial sectioning and immunohistochemistry increase the yield but are too labor-intensive and expensive for routine use. However, the introduction of the sentinel lymph node biopsy in lieu of axillary lymph node dissection in cases of breast carcinoma holds promise for making these methods practical and cost-effective.

Lymph node micrometastases from breast carcinoma: reviewing the dilemma

BACKGROUND

The presence or absence of regional lymph node metastases has been one of the most important determining factors in recommending adjuvant chemotherapy for patients with breast carcinoma. However, because of the 15-20% failure rate at 5 years for lymph node negative patients, other tumor-related prognostic factors have gained greater significance in this decision-making process. Many investigators have reported finding micrometastases that were not detected by routine sectioning of the lymph nodes but were identified by multiple sectioning and additional staining. This review attempts to evaluate the role of occult lymph node micrometastases and their relevance to disease recurrence.

METHODS

A literature search of the entire MEDLINE data base was conducted. All relevant articles were reviewed for the criteria they used to define micrometastases. The frequency of detection of micrometastases by various methodologies and the prognostic significance of such deposits were examined.

RESULTS

Tumor deposits involving the lymph nodes were found to be arbitrarily categorized as either micrometastases or macrometastases, with the cutoff point ranging from 0.2-2.0 mm. The detection rate of such deposits by conventional techniques was inadequate. Serial sectioning and immunohistochemistry appeared to increase the detection rate by 9-33%. A definite survival disadvantage was noted for patients with such occult metastases.

CONCLUSIONS

Current routine histologic examination of regional lymph nodes underestimates breast carcinoma metastases. Serial sectioning and immunohistochemistry increase the yield but are too labor-intensive and expensive for routine use. However, the introduction of the sentinel lymph node biopsy in lieu of axillary lymph node dissection in cases of breast carcinoma holds promise for making these methods practical and cost-effective.

[The effect of chlorhexidine varnish system on Streptococcus mutans in fissure plaques]

A chlorhexidine varnish system and a controlled releasing varnish were prepared by the authors. The release rate of chlorhexidine in vitro and the effects on S. mutans and S. sanguis in vivo were determined. The results showed that the system could selectively inhibit the growth of S. mutans in fissure plaque and had no effect on S. sanguis. The period of interaction between the layer of varnish and plaque was prolonged by the control-releasing reagent. The study suggests that the chlorhexidine varnish system is effective of anticaries and can maintain microflora balance in oral bacteria.

[Mineralization of human dental pulp cells in continued culture]

The purpose of this study was to understand the mineralization of human dental pulp cells in vitro. Pulp cells were isolated from human normal permanent teeth and cultured in normal tissue-culture medium. With continued culture, pulp cells formed cell nodules after 12-15 days, but no cell nodules were found from human gingiva fibroblasts. Pulp cells showed high alkaline phosphatase activity and the nodules were strongly stained by Von Kossa. Furthermore, the nodules showed high level of calcium and phosphorus by Energy-dispersive X-ray analysis and pulp cells had similar ultrastrusture with odontoblasts under TEM. The continued culture of pulp cells provides a useful system for studying differentiation and calcification of pulp tissue.

[Dynamic study on the mutagenic activity of organic concentration of water from one branch port of Huangpu River]

From 1991 to 1994, we studied the mutagenicity of drinking water in Shanghai by seasons by Ames test. The results indicated that the mean value of mutagenic activity of organic concentration on TA98 is 162 revertants per liter. Studies on the four branch ports of Huangpu river showed that they contributed 74% of the total mutagenicity, which accounted for the predominant fraction of the mutagenic activity of Shanghai drinking water. The mutagenicity of Hongkou branch was the highest, accounting for 1/3 of the total mutagenic activity of the 4 branches. Studies showed that the mutagenic activity of organic concentration of Hongkou branch water was declining year by year, and factors affecting the mutagenic activity were analysed.

[Comparison between the effects of rhCNTF on sensory and motor neuron of chicken embryo]

The effects of rhCNTF on dorsal root ganglia (DRG) sensory neurons and spinal cord (SC) motor neurons of 10-day chicken embryos were observed with serum-free culture. The results indicated that rhCNTF supported the survival and differentiation of these neurons and showed certain dose-dependent manners. No effect was found at 0.5 ng/ml rhCNTF concentration, a little survival promotive effect at 1.0-1.5 ng/ml, peak effect at 4 ng/ml and no more effects from 8.0 to 100 ng/ml. The survival number of neurons on 7th day was compared, and results showed higher sensitivity of sensory neuron to CNTF shortage than that of motoneuron. This suggests that survival effect of CNTF on motoneuron is only small part of its neurotrophic effects.

[Research progresses on signal transduction of neurotrophins]

Binding of neurotrophins and their receptors lead to dimerization and autophosphorylation of trks. Activated trkA initiates the Ras pathway and finally opens the transcriptions of immediate early genes and delayed response genes or participates directly in physiological responses. Target-derived neurotrophins bind to and induce phosphorylation of trk receptors at the axonal terminal. Active trk or NT-trk or other signal molecules can be retrogradely transported along the axon to transduct messages to neuronal nucleus. There are local autocrine and paracrine mechanisms besides target-derived NTs. Following nervous system injury, increased gene expressions of NTs and their receptors and increased retrograde axonal transport are helpful to survive and regenerate for injured neurons. Lacking NTs and their receptors will result in serious abnormal development of nervous system of mice.

[The effects of strontium in drinking water on growth and development of rat bone]

Effects of strontium at a high level in drinking water on growth and development of rat bone were studied. The results showed that Sr2+ concentration from 5 to 500 mg/L in drinking water could increase the contents of strontium in blood serum, urine, femur, mixilla and tooth in Wistar rats exposed to Sr2+ for 12 weeks with an obvious dose-response relationship. In addition, strontium at over 50 mg/L could decrease the contents of calcium in bone, increase the contents of calcium in tooth and bone density, and decrease the levels of calcium in blood serum except female rats at the 12th week. Effects of Sr2+ on body weight, body length, AKP activity of serum, calcium content of urine and breaking load of bended femur for rats were not found. However, there are differences in the effects of strontium on growth and development of bone between male and female rats. At the 12th week the content of calcium in blood serum decreased in male rats but increased in female rats in exposed groups. At the 4th and 8th weeks, urine Hop/Cr in male rats increased but it remained normal level in female rats. Sr2+ increased the bone density of mixilla in male rats but it did not increase that of femur in female rats. It is suggested that such changes may be a result of the differences in endocritic regulation and metabolic process between two sexes.

[Detection of types I, III and IV collagen in human cementum, periodontal ligament and alveolar bone]

The aim of the present study was to investigate distribution and composition of collagen Types I, III and IV in human cementum, periodontal ligament and alveolar bone with immunohistochemical localization and image analysis technique. The results showed that collagen Type I was 78.06% in periodontal ligament, 73.09% in cementum and 30.50% in alveolar bone; Type III was 11.73% in periodontal ligament and was also observed in apical cementum and bone tissue of alveolar socket; Type IV was restricted to the basement membrane of the blood vessles; Sharpey's fibers was stained by Type I and its periphery was demonstrated stronger staining by Type I and Type III as a sheath. These results provided necessary informations on healthy periodontal tissues that will be required for future studies on the effects of pathological and regenerative processes.

[Hemorheological disorders in patients with sudden deafness]

Fourteen hemorheological and related parameters of blood samples derived from 59 patients with sudden deafness were observed and were compared with those of blood samples got from 512 healthy persons. The ratio viscosity of whole blood (6.50 +/- 1.07), reduced viscosity of whole blood (12.37 +/- 1.80), and plasma viscosity (1.84 +/- 0.14) in male patients were significantly higher than those (6.05 +/- 0.63, 11.06 +/- 1.04, and 1.70 +/- 0.07, respectively) in male controls. The reduced viscosity of whole blood (16.62 +/- 3.87) and plasma viscosity (1.92 +/- 0.13) in female patients were also significantly higher than those (14.40 +/- 2.27 and 1.72 +/- 0.06, respectively) in female controls. The findings above suggest that there is an intimate relationship between the microcirculationary disorder resulting from hemorheological changes and the onset of sudden deafness. The parameters related to plasma viscosity revealed that there were higher concentrations of plasma fibrinogen and triglyceride in male patients than those in male controls, while the concentrations of plasma cholesterol and triglyceride were higher in female patients than in female controls. These results indicate that the factors which induce the change of plasma viscosity in male patients could not be the same as those in female patients. Thus, in the process of treating sudden deafness, besides the use of common devices such as reducing blood viscosity and improving microcirculation, some other special steps based on the hemorheological parameters derived from different sexes or individuals, should also be considered.

[Ultrastructure of adherence of Streptococcus mutans MT8148 and its glucosyltransferase deficient mutants]

The ultrastructure of adherence of Streptococcus mutans MT8148 and its glucosyltransferase deficient mutants were compared by Scanning Electronic Microscope. Four patterns of adherence of tested strains in the presence of sucrose were observed. These results suggest that the cell-associated GTase is responsible for firm aggregation of cells. However, cell free GTase is also important in aggregation between cells.

[LIM homeobox genes family in nervous system]

Homeobox genes define a class of genes containing homeobox sequences and encoding proteins, that are identified as transcription regulator controlling cellular development and differentiation, and controlling patterns of gene expression. LIM homeobox genes contain both a homeobox and a conservative sequences (encoded LIM domain). The members of the LIM homeobox genes family which have recently been identified include lin-11, mec-3, apterous(ap), isl-1, LH-2, Rlim, lim-1, lmx-1, Xlim-1 and Xlim-3. Recent findings suggested that products expressed by LIM homeobox genes family play an important role in adjusting differentiation and developmental of the organism. The effects of LIM homeobox genes in the differentiation and development of neurons are currently attracting more and more attention.

[Improvement of the pre-hypertensive inherited cardiac dearangements with phenylalanine in essential hypertension]

OBJECTIVE

To assess whether phenylalanine intervention can effectively improve the pre-hypertensive inherited cardiac hypertrophy and systolic dysfunction in young offsprings of patients with essential hypertension (ER).

METHODS

Ninty-six normotensive adolescents with hypertensive family history and associated with inherited cardiac hypertrophy, i.e, interventricular, septum (IVST) and (or) left ventricular post wall thickness (PWT) > or = 10.5 mm, were screened according to the normal range criteria of ultrasonic-cardiogram (UCG) obtained previously from 50 normotensive adolescents without hypertensive genetic predisposition. The UCG parameters before and after 3, 6, 9 months of observation were compared between intervention group (Phe 1 g/d 58 subjects) and placebo-control group (placebo 1 g/d, 38 subjects) in 2 separate trials by a double-blind, randomized, cross-over and comparable placebo-control design.

RESULTS

The hypertrophy and dilatation of ascending aorta and left heart structure were regressed after intervention, i.g, the changes after 9 months intervention, IVST dropped from 10.9 +/- 1.2 to 9.2 +/- 0.6 mm, PWT from 9.5 +/- 1.0 to 8.6 +/- 0.6 mm, left ventricular mass index from 92 +/- 15 to 70 +/- 11 g/m2; All of the parameters reflecting the systolic function of left ventricle were improved in pooled group of 2 trials. The UCGs after placebo was fundamentally not changed except some sporadic values. The results were similar in 2 separate trials. The improvement after Phe and its return towards that of pre-intervention after stope were remarked at 6 months.

CONCLUSION

The inherited cardiac dearrangement seen in adolescents with hypertensive genetic predisposition can be assumed to be the pre-hypertensive changes of EH. It can be reversed by phenylalanine--a natural and essential amino-acid.

[The characterization of Streptococcus mutans MT8148 and its glucosyltransferase deficient mutants]

The characterization of GTase-deficient mutants of S. mutans MT8148 was analysed to understand the possible virulence of GTase. In the presence of 1% sucrose, these mutants lost the ability to adhere to glass wall and the insoluble glucan synthesis was dramatically decreased. The GTase enzyme activity for insoluble glucan synthesis of these mutants was also decreased. Western blot using anti-CAGTase polyclonal antibody and anti-GTFI or anti-GTFSI monoclonal antibody showed the lack of the corresponding GTase which further confirmed the mutation of specific GTase gene.

Menstrual bleeding patterns in Chinese women using the Norplant subdermal implant

An analysis of the menstrual diary records of 306 cases of Norplant users over 5 years is reported. The results indicate that the disturbances of menstrual cycles during Norplant use were mainly caused by changes in the total number of vaginal bleeding days. Menstrual patterns were irregular and prolonged. Disturbances of the menstrual pattern were improved after 6-12 months of use, mainly showing a decrease in the number of spotting days. About 30-40% of users may regain their normal menstrual pattern after 1 year of use. There was a proportion of cases with an abnormal menstrual pattern throughout the 5 years of use, but the gross cumulative termination rate for menstrual problems was only 13.0%. Norplant users are susceptible to an increase in the number of spotting days and irregular bleeding. The main reason for termination of contraceptive use was prolonged bleeding for a long time. This is important information that should be provided in counselling potential Norplant acceptors, especially the changes in menstrual pattern. We also have a responsibility to try to find a treatment for prolonged bleeding.

Mouse lung tumors exhibit specific Ki-ras mutations following transplacental exposure to 3-methylcholanthrene

A pharmacogenetic mouse model was utilized to determine the role of Cyp1a1 expression on the formation of Ki-ras mutations in lung tumors following transplacental exposure to polycyclic aromatic hydrocarbons (PAHs). A backcross between Ah responsive male B6D2F1 mice and nonresponsive female DBA mice resulted in a litter in which both responsive and nonresponsive fetuses resided in the same nonresponsive maternal environment. Pregnant mothers received a single i.p. injection of either 10 or 30 mg/kg of 3-methylcholanthrene (MC) or olive oil vehicle on day 17 of gestation. At the higher dose of MC, the responsive offspring of both sexes had significantly (P < 0.05) higher incidences of lung tumors than their nonresponsive littermates. The male responsive mice also exhibited a significantly increased liver tumor incidence over the nonresponsive mice at the P < 0.05 level. Administration of 10 mg/kg of MC caused a very low incidence of lung tumors and did not result in the appearance of macroscopically visible liver tumors. Exons 1 and 2 of the Ki-ras gene were amplified from paraffin-embedded tissue samples. The PCR products were screened by allele-specific oligonucleotide hybridization (ASO). Thirteen of 16 lung tumors (81%) screened exhibited point mutations in the 12th or 13th codon, including seven tumors that contained GGT-->GTT (GLY12-->VAL12) transversions, four which exhibited GGT-->TGT (GLY12-->CYS12) transversions, and two which contained GGC-->CGC (GLY13-->ARG13) transversions. None of the tumors had mutations at codon 61. The results obtained by ASO were confirmed by cloning and sequence analysis of the PCR products from four of these tumors. Within the subset of 16 tumors examined in this study, the same types of mutations in the Ki-ras gene were generally present in both responsive and nonresponsive mice, although G-->C transversions were found in two tumors from a single responsive female mouse. Interestingly, while both males and females exhibited the GGT-->GTT mutations at codon 12, the GGT-->TGT transversion was only found in male mice. These results are consistent with a key role for Cyp1a1 in modulating individual susceptibility to cancer formation through the formation of reactive intermediates that bind to DNA and result in activating mutations in key regulatory molecules.