APC-mediated proteolysis of Ase1 and the morphogenesis of the mitotic spindle

The molecular mechanisms that link cell-cycle controls to the mitotic apparatus are poorly understood. A component of the Saccharomyces cerevisiae spindle, Ase1, was observed to undergo cell cycle-specific degradation mediated by the cyclosome, or anaphase promoting complex (APC). Ase1 was degraded when cells exited from mitosis and entered G1. Inappropriate expression of stable Ase1 during G1 produced a spindle defect that is sensed by the spindle assembly checkpoint. In addition, loss of ASE1 function destabilized telophase spindles, and expression of a nondegradable Ase1 mutant delayed spindle disassembly. APC-mediated proteolysis therefore appears to regulate both spindle assembly and disassembly.     

Evaluation of staging conformity CTNM and PTNM for lung cancer

A series of 225 consecutive lung cancer patients were prospectively randomized into study group (75 patients) and control group (150 patients), and the conformity of CTNM and PTNM staging was was evaluated. Radical mediastinal lymph node dissection was performed and in average 11.5 nodes were dissected in the study group. Only suspected metastatic lymph nodes, 3.4 in average, were dissected in the control group. CTNM classification was made according to clinical examination, chest image examination and bronchoscopy in every patient and PTNM staging was made after thoracotomy. Then the conformity of CTNM and PTNM staging was examined by Kappa value. The results showed that the Kappa value in the two groups was lower than the effective standard value of 0.4. The study group (Kappa = 0.097) was poorer than the control group (Kappa = 0.371). The principal influencing cause was that N was not well evaluated by CTNM. The principal manifestation of the staging inconsistency was that the stage of PTNM was advanced than that of CTNM. In the study group 43% of patients showed an increased stage and this occurred in 33% of the control group (P < 0.05). The results of the study show that at present the CTNM staging has not fully satisfied the needs of practice and requires to be further improved. The operative procedure which only dissects suspected involved mediastinal lymph nodes can not meet the needs of PTNM staging. In order to make PTNM staging accurately and evaluate the results of treatment for lung cancer, radical mediastinal lymph node dissection should be performed in every operable patient.     

An eukaryotic RuvB-like protein (RUVBL1) essential for growth

A human protein (RUVBL1), consisting of 456 amino acids (50 kDa) and highly homologous to RuvB, was identified by using the 14-kDa subunit of replication protein A (hsRPA3) as bait in a yeast two-hybrid system. RuvB is a bacterial protein involved in genetic recombination that bears structural similarity to subunits of the RF-C clamp loader family of proteins. Fluorescence in situ hybridization analysis demonstrated that the RUVBL1 gene is located at 3q21, a region with frequent rearrangements in different types of leukemia and solid tumors. RUVBL1 co-immunoprecipitated with at least three other unidentified cellular proteins and was detected in the RNA polymerase II holoenzyme complex purified over multiple chromatographic steps. In addition, two yeast homologs, scRUVBL1 and scRUVBL2 with 70 and 42% identity to RUVBL1, respectively, were revealed by screening the complete Saccharomyces cerevisiae genome sequence. Yeast with a null mutation in scRUVBL1 was nonviable. Thus RUVBL1 is an eukaryotic member of the RuvB/clamp loader family of structurally related proteins from bacteria and eukaryotes that is essential for viability of yeast.     

Tumor angiogenesis and metastasis: correlation in invasive renal cell carcinoma

BACKGROUND: Experience suggests that tumor growth is dependent on angiogenesis. The intensity of angiogenesis in human cancer is reported to be predictive of the probability of metastasis in many types of cancer. The aims of this study were 1) to determine the relationship of microvessel density (MVD) in renal cell carcinoma to pathologic stage, and 2) to evaluate the role of MVD in metastasis. METHODS: Paraffin-embedded tumor specimens were reviewed from 34 unselected patients with RCC who had undergone surgery from 1986 to 1990 at Taichung Veterans General Hospital. The pathology findings and clinical records were reviewed to note relationships between pathologic stage and whether or not metastasis had occurred. Specimens were studied from 16 cases (eight Stage I cancers, five Stage II and three Stage III) without metastasis and from 18 cases (two Stage I, six Stage II, six Stage III and four Stage IV) in which metastasis later developed. Microvessels were highlighted by immunostaining endothelial cells for factor VIII-related antigen. Microvessels were counted in a x-400 field (0.1885 mm2/field) in the most active areas of neovascularization. RESULTS: The 16 patients without metastasis have survived for between 65 and 136 months (mean, 94.5 months), up to the present time. Of the 18 patients with metastasis, 15 died and three survived, with mean survivals of 42.8 months (range, 12-99 months). Mean overall MVD was 99.6 vessels; mean MVD was 98.5, 96.2, 109.3 and 90.0 in Stages I, II, III and IV tumors, respectively. Mean MVD was 99.3 in patients without metastasis and 99.9 in patients with metastasis. CONCLUSIONS: MVD does not correlate with pathologic stage and is of no prognostic significance in renal cell carcinoma.     

Transneuronal WGA-HRP: can it demonstrate development of ocular dominance patches and effects of monocular deprivation?

We have attempted to use intraocular injections of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) to label ocular dominance patches in developing layer 4 of cat visual cortex. The cortices of animals killed at 49 days or later showed normal ocular dominance patches similar to those seen in [3H]proline material. Animals killed at 42 days showed some patches, but also showed unsegregated regions. Animals killed younger were difficult to stain and did not have patches. We also examined the ability of the WGA-HRP technique to demonstrate the effects of monocular deprivation (MD). MD for the first 3 months of life produced expansion of the afferents from the nondeprived eye and retraction of the patches from the deprived eye. One week of MD at about 5 weeks of age produced an expansion of the patches innervated by the nondeprived eye, but did not obviously affect the patches innervated by the deprived eye. We conclude that WGA-HRP is useful for examining the effects of long-term MD on ocular dominance patches but not for following the development of segregation. Its advantages over the [3H]proline technique are that it does not require a delay of many weeks before the sections can be examined and is much less expensive.     

Identification and characterization of a novel member of the fibroblast growth factor family

A new member of the fibroblast growth factor (FGF) family, FGF-13, has been molecularly cloned as a result of high throughput sequencing of a human ovarian cancer cell library. The open reading frame of the novel human gene (1419 bp) encodes for a protein of 216 a.a. with a molecular weight of 22 kDa. The FGF-13 sequence contains an amino-terminal hydrophobic region of 23 a.a. characteristic of a signal secretion sequence. FGF-13 is most homologous, 70% similarity at the amino acid level, to FGF-8. Northern hybridization analysis demonstrated prominent expression of FGF-13 in human foetal and adult brain, particularly in the cerebellum and cortex. In proliferation studies with BaF3 cells, FGF-13 preferentially activates cell clones expressing either FGF receptor variant, 3-IIIc or 4. The signal transduction pathways of FGF-13 and FGF-2 were compared in rat hippocampal astrocytes. The two FGFs induce an equivalent level of tyrosine phosphorylation of mitogen-activated protein kinase (MAPK) and c-raf activation. However, FGF-13 is more effective than FGF-2 in inducing the phosphorylation of phospholipase C-gamma (PLC-gamma). Treatment of neuronal cultures from rat embryonic cortex with FGF-13 increases the number of glutamic acid decarboxylase immunopositive neurons, the level of high-affinity gamma-aminobutyric acid (GABA) uptake, and choline acetyltransferase enzyme activity. The GABAergic neuronal response to FGF-13 treatment is rapid with a significant increase occurring within 72 h. We have identified a novel member of the FGF family that is expressed in the central nervous system (CNS) and increases the number as well as the level of phenotypic differentiation of cortical neurons in vitro.     

Polarcardiographic criteria for myocardial infarction in Chinese men

A biochemical study was performed in two patients submitted to insulin coma therapy. The injection of insulin resulted in a decrease of free and total tryptophan as well as tyrosine in plasma, while NEFA were not influenced by this treatment. The ratio of tryptophan to tyrosine was enhanced. The administration of glucose after insulin provoked an increase of free and total tryptophan. The results support the hypothesis that in man insulin may favor the uptake of tryptophan by the brain, and enhance the synthesis of cerebral serotonin.     

Equalization digital on-channel repeater in the single frequency networks

Digital On-Channel Repeater (DOCR) can be used for Single Frequency Networks (SFN's). It is much simple and low cost compared to Distributed Transmitter which needs Studio to Transmitter Link (STL). However, traditional DOCR has one of those defects such as a power limit, a long time system processing delay or a poor output signal quality. In order to overcome all of those defects, we introduce Equalization DOCR (EDOCR) which regenerates the original 8-VSB output signal with relatively short time system processing delay. Lab. and Field test results show that the EDOCR can eliminate the loop-back signal up to 5.5 dB with 5.5 /spl mu/s system processing delay. By using EDOCR, we can save spectrum resources and extend coverage areas.