311 cases of chronic osteomyelitis treated by soaking with ganlingsan liquid

From 1992 to 1995, 311 cases of chronic osteomyelitis (including 145 cases of hematogenic osteomyelitis, 147 cases of traumatic osteomyelitis, 8 cases of secondary osteomyelitis after local infection, 4 cases due to other causes, and 7 cases with cause unknown) were treated by soaking with Ganlingsan liquid. The average treatment course was 69.5 days. The results showed that 260 cases were cured, 26 cases markedly effective, 20 cases improved, and 5 cases ineffective. The evaluation of the function revealed that 150 cases were excellent, 129 cases good, 10 cases improved, and 22 cases poor. 111 patients recovered from abnormal erythrocyte sedimentation rate. External fixation was applied at the same time for the patients accompanied by nonunion of fracture, and the therapeutic effect was also satisfactory.

Stat5a and Stat5b: fraternal twins of signal transduction and transcriptional activation

Stat5a and Stat5b are discretely encoded transcription factors that mediate signals for a broad spectrum of cytokines. Their activation is often an integral component of redundant cytokine signal cascades involving complex cross-talk and pleiotropic gene regulation by Stat5 has been implicated in cellular functions of proliferation, differentiation and apoptosis with relevance to processes of hematopoiesis and immunoregulation, reproduction, and lipid metabolism. Although Stat5a and Stat5b show peptide sequence similarities of > 90%, targeted gene disruptions in mice yield distinctive phenotypes. Prolactin-directed mammary gland maturation fails without functional Stat5a, while disruption of Stat5b in males mitigates growth hormone effects on hepatic function and body mass. The molecular basis for this biologic dichotomy is probably multifaceted. Limited structural dissimilarities between the Stat5a and Stat5b transactivation domains, or subtle differences in the DNA-binding affinities of Stat5 dimer pairs undoubtedly influence gene regulation, but cell-dependent asymmetries in availability of phosphorylated Stat5 can be an underlying factor. Differences in serine phosphorylation(s) of Stat5a and Stat5b, or Stat5 associations with adaptor proteins or co-transcription factors are other potential sources of functional disparity and the signal amplitude, frequency or duration also can be significant. In addition to Stat5 signal attenuation by phosphatase actions or classical feedback inhibition, truncated forms of Stat5 lacking in transactivation capacity may compete upstream for activation and diminish access of full length molecules to DNA binding sites.

Isolation and characterization of SYN1, a RAD21-like gene essential for meiosis in Arabidopsis

The proper pairing, recombination, and segregation of chromosomes are central to meiosis and sexual reproduction. The syn1 mutation was previously identified as a synaptic mutant in a T-DNA-tagged population of plants. SYN1 has been isolated and found to exhibit similarity to Schizosaccharomyces pombe RAD21 and RAD21-like proteins, which are required for chromosome condensation and sister chromatid cohesion during mitosis. Plants homozygous for syn1 are male and female sterile and show defects in chromosome condensation and pairing beginning at leptonema of meiosis I. Fragmentation of the chromosomes was observed at metaphase I. Alternative promoters produced two SYN1 transcripts. One transcript was expressed at low levels in most tissues, whereas the other was expressed only in prebolting buds. DNA blot analyses suggest that Arabidopsis contains a small RAD21 gene family. Consistent with the DNA blot data, a second Arabidopsis RAD21-like gene has been identified. These results suggest that different RAD21-like proteins play essential roles in chromosome condensation and pairing during both meiosis and mitosis.

Vaginal misoprostol for pre-abortion cervical priming: is there an optimal evacuation time interval?

OBJECTIVE

To determine the optimal evacuation time interval in the use of vaginal misoprostol for cervical priming before first trimester termination of pregnancy.

DESIGN

Prospective double-blind randomised study.

SETTING

Fertility Control Centre, National University Hospital, Singapore.

METHODS

Sixty healthy nulliparous women requesting legal termination of pregnancy between 6 and 11 weeks of gestation were randomly allocated to either the 400 microg or 600 microg misoprostol group. Vacuum aspiration was performed after three hours in the 400 microg group and at the end of two hours in the women given 600 microg misoprostol. Using Hegar's dilator, degree of cervical dilatation before operation was measured. Other parameters assessed included the amount of additional dilatation required (if < Hegar 8), pre-operative and intra-operative blood loss, and associated side effects.

RESULTS

For the 600 microg group, only five women (16.7%) achieved a cervical dilatation of > or = 8 mm, compared with 28 women (93.3%) in the 400 microg group. Using the 400 microg misoprostol group as a baseline, the odds ratio was 0.014 (95% CI 0.003-0.080) for 600 microg for successful pre-operative cervical dilatation of > or = 8 mm. The mean cervical dilatation for 400 and 600 microg misoprostol was 8.1 mm and 6.6 mm, respectively (P < 0.001). Despite the shorter evacuation time interval of two hours, the 600 microg dose was associated with an increase in side effects such as vaginal bleeding, abdominal pain and a fever of > 38.0 degrees C. However, other than abdominal pain, no significant differences in the frequency of these side effects were shown.

CONCLUSION

Use of 400 microg misoprostol with a minimal evacuation time interval of three hours still appears the optimal dosage and evacuation time for cervical priming before first trimester termination of pregnancy.

Digital mapping of bacterial artificial chromosomes by fluorescence in situ hybridization

The bacterial artificial chromosome (BAC) has become the most popular tool for cloning large DNA fragments. The inserts of most BAC clones average 100-200 kilobases (kb) and molecular characterization of such large DNA fragments is a major challenge. Here we report a simple and expedient technique for physical mapping of BAC inserts. Individual BAC molecules were immobilized on glass slides coated with Poly-L-lysine. The intact circular BAC molecules were visualized by fluorescence in situ hybridization using BAC DNA as a probe. The 7.4 kb BAC vector was extended to approximately 2.44 kb per micrometer. Digitally measured linear distances can be transformed into kilobases of DNA using the extension of BAC vector as a standard calibration. We mapped DNA fragments as small as 2 kb directly on circular BAC molecules. A rice BAC clone containing both tandem and dispersed repeats was analyzed using this technique. The distribution and organization of the different repeats within the BAC insert were efficiently determined. The results showed that this technique will be especially valuable for characterizing BAC clones that contain complex repetitive DNA sequences.

Influence of lymphocytic thyroiditis on the prognostic outcome of patients with papillary thyroid carcinoma

Both the association between lymphocytic thyroiditis (LT) and papillary thyroid carcinoma (PTC), and the prognostic significance of lymphocytic infiltrate in patients with thyroid malignancy, remain controversial. We examine the above relationships by retrospectively reviewing our series of patients treated for differentiated nonmedullary thyroid carcinoma at University of California-San Francisco over a 25-yr period (1970-1995). Of the 631 patients with complete data for analysis, 128 patients (20.3%) showed concomitant histologic evidence of LT and 503 patients (79.7%) had no evidence of LT. Prognostic outcome was assessed using Kaplan-Meier survival plots and analysis of risk factors by Cox's proportional-hazard modeling. The cohort with LT revealed a higher frequency of PTC (97.7% vs. 87.3%) and female patients (85.2% vs. 66.8%), a lower frequency of extrathyroidal invasion (7.8% vs. 23.3%) and nodal metastases (25.8% vs. 43.3%), and absence of distant metastases (0% vs. 4.8%), respectively, compared with those without LT. At initial surgery, a significantly greater proportion of patients with LT belonged to lower pathological tumor-node-metastasis stages, compared with those without LT (stage 1, 86.7% vs. 73%; stage 2, 4.7% vs. 8.3%; stage 3, 8.6% vs. 15.3%; and stage 4, 0% vs. 3.4%). Over a mean +/- SE follow-up period of 11.1 +/- 0.4 yr, patients with LT had significantly lower cancer recurrence rate (6.3% vs. 24.1%; P < 0.0001) and cancer mortality rate (0.8% vs. 8.0%; P = 0.001), respectively, compared with those without LT. In summary, our series showed a relatively common occurrence of LT in patients with PTC, and we believed that lymphocytic infiltration developed mainly in response to the tumor itself. We also found a more favorable course of PTC in the presence of LT; this supports the hypothesis that lymphocytic infiltration represents a form of immune reaction to control tumor growth and proliferation.

Toward the experimental codon reassignment in vivo: protein building with an expanded amino acid repertoire

The high precision and fidelity of the genetic message transmission are ensured by numerous proofreading steps, from DNA replication and transcription to protein translation. The key event for translational fidelity is the proper codon assignment for 20 canonical amino acids. An experimental codon reassignment is possible for noncanonical amino acids in vivo using artificially constructed expression hosts under efficient selective pressure. However, such amino acids may interfere with the cellular metabolism and thus do not belong to the 'first' or 'restricted' part of the universal code, but rather to a second or 'relaxed' part, which is limited mainly by the downstream proofreading in the natural translational machinery. Correspondingly, not all possible alpha-amino acids can be introduced into proteins. The aim of this study is to discuss biological and evolutionary constraints on possible candidates for this second coding level of the universal code. Engineering of such a 'second' code is expected to have great academic as well as practical impact, ranging from protein folding studies to biomedicine.

Intervening attenuation affects first-order statistical properties of ultrasound echo signals

Previous studies show that first-order statistical properties of ultrasound echo signals are related to the effective number of scatterers in the "resolution cell" of a pulse-echo ultrasound system. When the effective number of scatterers is large (~10 or more) this results in echo signals whose amplitude follows a Rayleigh distribution, with the RF echo signal obeying Gaussian statistics; deviation from Rayleigh or Gaussian statistics yields information on scatterer number densities. In this paper, the influence of the medium's attenuation on non-Gaussian properties of the echo signal is considered. Preferential attenuation of higher frequency components of a pulsed ultrasound beam effectively broadens the beam and increases the resolution cell size. Thus, the resultant non-Gaussian parameter for broad bandwidth excitation of the transducer depends not only on the scatterer number density but also on the attenuation in the medium. These effects can be reduced or eliminated by using narrow-band experiments.

Stimulation of Stat5 by granulocyte colony-stimulating factor (G-CSF) is modulated by two distinct cytoplasmic regions of the G-CSF receptor

In a manner similar to many other cytokines, treatment of cells with granulocyte CSF (G-CSF) has been shown to induce the tyrosine phosphorylation of the STAT proteins. Activation of Stat1 and Stat5 by G-CSF requires the membrane-proximal cytoplasmic domain of the receptor, including box1 and box2, while G-CSF-stimulated tyrosine phosphorylation of Stat3 also requires a region distal to box 2. In this study, we show that although the membrane-proximal 55 amino acids of the G-CSF receptor are sufficient for activation of Stat5, the maximal rate of Stat5 activation requires an additional 30 amino acids of the cytoplasmic domain. In contrast, the distal carboxyl-terminal region of the receptor appears to down-regulate Stat5 activation in that deletion of this carboxyl terminus results in increased amplitude and prolonged duration of Stat5 activation by G-CSF. Significantly, expression of a truncated dominant-negative Stat5 protein in hemopoietic cells not only inhibits G-CSF-dependent cell proliferation, but also suppresses cell survival upon G-CSF withdrawal. We further show that a potential protein tyrosine phosphatase may play a critical role in the down-regulation of G-CSF-stimulated Stat5 activation. These results demonstrate that two distinct cytoplasmic regions of the G-CSF receptor are involved in the regulation of the intensity and duration of Stat5 activation, and that Stat5 may be an important player in G-CSF-mediated cell proliferation and survival.

Retrotransposon-related DNA sequences in the centromeres of grass chromosomes

Several distinct DNA fragments were subcloned from a sorghum (Sorghum bicolor) bacterial artificial chromosome clone 13I16 that was derived from a centromere. Three fragments showed significant sequence identity to either Ty3/gypsy- or Ty1/copia-like retrotransposons. Fluorescence in situ hybridization (FISH) analysis revealed that the Ty1/copia-related DNA sequences are not specific to the centromeric regions. However, the Ty3/gypsy-related sequences were present exclusively in the centromeres of all sorghum chromosomes. FISH and gel-blot hybridization showed that these sequences are also conserved in the centromeric regions of all species within Gramineae. Thus, we report a new retrotransposon that is conserved in specific chromosomal regions of distantly related eukaryotic species. We propose that the Ty3/gypsy-like retrotransposons in the grass centromeres may be ancient insertions and are likely to have been amplified during centromere evolution. The possible role of centromeric retrotransposons in plant centromere function is discussed.

[Analysis on the risk factors in patients with diabetes mellitus from population in mining districts--a population-based case-control study]

According to data from prevalence study on population from Pingdingshan coal mining districts in Henan province, we analysed 174 patients with diabetes mellitus(DM) and 3,066 control subjects with normal blood glucose(NGT) by a population-based case-control study. After the adjustment of other factors and controlled on confounding factors, the results of unconditional logistic multivariate regression analysis demonstrated that age, DM history of mother and sib, highest BMI through one's life, higher concurrent WHR, higher systolic blood pressure, frequently eating Chinese sorghum and legume may serve as independent risk factors of DM, their odds ratios(OR) were 2.04, 6.04, 2.24, 1.85, 2.57, 1.51, 2.22, 1.25 and their population attribution rates (PAR%) were 80.04%, 7.19%, 3.18%, 37.35%, 48.80%, 8.15%, 3.20%, 10.63% respectively. Higher occupational physical activity and frequently eating vegetables of light colour might serve as independent protective factors of DM, with ORs 0.89 and 0.50 and PAR% of -19.20% and -269.5% respectively. Confounding analysis showed that age was both a positive and negative confounding factor to other factors in the logistic regression model.

Randomized trial to determine optimal dose of vaginal misoprostol for preabortion cervical priming

OBJECTIVE

To determine the optimal dosage of vaginal misoprostol for cervical priming before vacuum aspiration abortion.

METHODS

One hundred twenty women were assigned randomly to receive 200, 400, 600, or 800 microg of misoprostol given vaginally. Vacuum aspiration was performed 3-4 hours after the insertion of misoprostol tablets. The degree of cervical dilation before operation was measured with a Hegar dilator. Preoperative and intraoperative blood loss and associated side effects also were assessed.

RESULTS

Twenty-nine (96.7%) women in the 400-microg group and all in the 600-microg and 800-microg groups achieved cervical dilation of at least 8 mm. The success rate for the 200-microg group was only 23.3%, significantly less efficacious than the 400-microg dose (odds ratio 95.3; 95% confidence interval 10.9, 830.9; P < .001). There was no significant difference among the 400-, 600-, and 800-microg groups (P = .364) with respect to achieving cervical dilation at least 8 mm. However, 800 microg was associated with significantly more side effects than 600 microg (preoperative and intraoperative blood loss, P < .001; abdominal pain, P = .005; products of conception at os, P < .001; fever higher than 38.0C, P = .002). When 400 microg and 600 microg were compared, we found that the higher dose also was associated with significantly more side effects. The 600-microg group was used twice in the comparison, but all P values remained significant even after the Bonferroni adjustment for multiple comparisons.

CONCLUSION

Vaginal application of 400 microg of misoprostol is the optimal dose for vacuum aspiration preabortion cervical dilation in first-trimester nulliparas.

Non-Rabl patterns of centromere and telomere distribution in the interphase nuclei of plant cells

At the anaphase of cell divisions, the divided chromosomes move to the two poles, with the centromeres as heads and telomeres as tails. Such a polarized orientation of centromeres and telomeres is believed to be preserved in the interphase and is known as Rabl model. We analyzed the distributions of centromeres and telomeres in interphase nuclei from several plant species. Although Rabl polarity was observed in wheat, rye, barley and oats, non-Rabl patterns were discovered in sorghum, rice and maize. In the non-Rabl patterns, both centromeres and telomeres were dispersed throughout the interphase nucleus, except in the area occupied by the nucleolus. Both Rabl and non-Rabl distribution patterns of centromeres and telomeres were consistent in interphase nuclei derived from meristematic root tip cells, microspore mother cells and differentiated leaf cells. Our study demonstrated that there is a diversity of interphase chromatin organization and that the classical Rabl model is not universal in plant species.

Effects of airway inflammation on cough response in the guinea pig

We have developed a guinea pig model for cough related to allergic airway inflammation. Unanesthetized animals were exposed to capsaicin aerosols for 10 min, and cough frequency was counted during this period. The cough evaluation was performed by the following three methods: visual observation, acoustic analysis, and monitoring of pressure changes in the body chamber. These analyses clearly differentiated a cough from a sneeze. To elucidate the relationship between cough response and airway inflammation, animals were immunosensitized and multiple challenged. Sensitized guinea pigs presented no specific changes microscopically, but multiple-challenged animals showed an increased infiltration of inflammatory cells into the airway. Cough number in response to capsaicin increased significantly from 4.7 +/- 1.4 coughs/10 min in normal animals to 10.6 +/- 2.0 coughs/10 min in sensitized animals and further to 22.8 +/- 1.3 coughs/10 min in multiple-challenged animals. This augmented cough frequency was significantly inhibited by the inhalation of tachykinin-receptor antagonists and by oral ingestion, but not inhalation, of codeine phosphate. The results suggest that airway inflammation potentiates an elevation of cough sensitivity in this model.

Cyclin D3-associated kinase activity is regulated by p27kip1 in BALB/c 3T3 cells

We report that cyclin D3/cdk4 kinase activity is regulated by p27(kip1) in BALB/c 3T3 cells. The association of p27(kip1) was found to result in inhibition of cyclin D3 activity as measured by immune complex kinase assays utilizing cyclin D3-specific antibodies. The ternary p27(kip1)/cyclin D3/cdk4 complexes do exhibit kinase activity when measured in immune complex kinase assays utilizing p27(kip1)-specific antibodies. The association of p27(kip1) with cyclin D3 was highest in quiescent cells and declined upon mitogenic stimulation, concomitantly with declines in the total level of p27(kip1) protein. The decline in this association could be elicited by PDGF treatment alone; this was not sufficient, however, for activation of cyclin D3 activity, which also required the presence of factors in platelet-poor plasma in the culturing medium. Unlike cyclin D3 activity, which was detected only in growing cells, p27(kip1) kinase activity was present throughout the cell cycle. Since we found that the p27(kip1) activity was dependent on cyclin D3 and cdk4, we compared the substrate specificity of the active ternary complex containing p27(kip1) and the active cyclin D3 lacking p27(kip1) by tryptic phosphopeptide mapping of GST-Rb phosphorylated in vitro and also by comparing the relative phosphorylation activity toward a panel of peptide substrates. We found that ternary p27(kip1)/cyclin D3/cdk4 complexes exhibited a different specificity than the active binary cyclin D3/cdk4 complexes, suggesting that p27(kip1) has the capacity to both inhibit cyclin D/cdk4 activity as well as to modulate cyclin D3/cdk4 activity by altering its substrate preference.

Rice (Oryza sativa) centromeric regions consist of complex DNA

Rice bacterial artificial chromosome clones containing centromeric DNA were isolated by using a DNA sequence (pSau3A9) that is present in the centromeres of Gramineae species. Seven distinct repetitive DNA elements were isolated from a 75-kilobase rice bacterial artificial chromosome clone. All seven DNA elements are present in every rice centromere as demonstrated by fluorescence in situ hybridization. Six of the elements are middle repetitive, and their copy numbers range from approximately 50 to approximately 300 in the rice genome. Five of these six middle repetitive DNA elements are present in all of the Gramineae species, and the other element is detected only in species within the Bambusoideae subfamily of Gramineae. All six middle repetitive DNA elements are dispersed in the centromeric regions. The seventh element, the RCS2 family, is a tandem repeat of a 168-bp sequence that is represented approximately 6,000 times in the rice genome and is detected only in Oryza species. Fiber-fluorescence in situ hybridization analysis revealed that the RCS2 family is organized into long uninterrupted arrays and resembles previously reported tandem repeats located in the centromeres of human and Arabidopsis thaliana chromosomes. We characterized a large DNA fragment derived from a plant centromere and demonstrated that rice centromeres consist of complex DNA, including both highly and middle repetitive DNA sequences.

Estimating the spatial autocorrelation function for ultrasound scatterers in isotropic media

The autocorrelation function pertaining to spatial distributions of ultrasonic scatterers in soft tissue is believed to contain useful information related to tissue morphology. A simple processing method applied to radio-frequency echo signals estimates this function for a sample having isotropic scattering conditions. It utilizes backscattered echo signals from the sample and echo signals from a reference object having defined scattering properties. The ratio of the echo signal power spectrum from the sample to the echo signal power spectrum from the reference object is obtained, and corrected for attenuation differences between the two media. This yields a "form factor" for the sample, whose inverse Fourier transform is the autocorrelation function. The method was tested using tissue-mimicking samples for which spatial autocorrelation functions could be modeled from the dimensions of embedded scatterers. The shapes of the measured autocorrelation functions were in reasonable agreement with those estimated, although measured functions overestimated the function at small lag distances. Scatterer diameters estimated from the zeros of the autocorrelation function agreed to within 6% of expected values when the measurement system bandwidth satisfied minimal criteria.

Liquid or solid ultrasonically tissue-mimicking materials with very low scatter

A new tissue-mimicking material for ultrasound, using evaporated milk as the primary absorption component, is described. It has very low backscatter but still exhibits the 1540 m s-1 propagation speed and proportionality of attenuation coefficient and frequency over the diagnostic frequency range. The material can be produced in solid or liquid form with attenuation coefficient slopes spanning the range 0.1-0.7 dB cm-1 MHz-1. The liquid form is useful in phantoms where detailed beam patterns are to be determined, either involving translation of measurement devices in the liquid or phantoms with fibers present for causing the only detectable echoes. In the latter case, the liquid quality allows removal of liquid with one attenuation coefficient slope and replacement with another. The solid form may be more useful than the liquid for two reasons. First, many simulated lesions (including ones that produce essentially no internal echoes) can lie in the scan slice with positions extending over the entire image area without enhancement or shadowing effects being of concern. Second, the lack of significant backscatter from the material in the absence of added scatterers allows the backscatter coefficient to be varied over a considerable range. A critical result is that intrinsic material contrast between targets and surroundings can be accurately predicted in terms of the concentrations of added scatterers and, assuming all scatterers are of the same type, the contrast will be completely independent of frequency. Use of the fungicide thimerosal eliminates deterioration, and ultrasonic properties have been shown to be stable over 2.5 years.

Prolonged STAT1 activation related to the growth arrest of malignant lymphoma cells by interferon-alpha

Multiple biologic effects of interferon-alpha (IFN-alpha), including cell growth inhibition and antiviral protection, are initiated by tyrosine phosphorylation of STAT proteins. Although this signal pathway has been intensively investigated, the relevance of STAT signal persistence has received scant attention. Using paired isogenic lymphoma cells (Daudi), which either are sensitive or resistant to growth inhibition by IFN-alpha, we found comparable initial tyrosine phosphorylation of multiple STAT proteins; however, the phosphorylation durations and associated DNA-binding activities diverged. Phosphorylation and DNA-binding capacity of STAT1 decreased after 4 to 8 hours in resistant cells, as compared with 24 to 32 hours in sensitive cells, whereas phosphorylation of STAT3 and STAT5b was briefer in both lines. Functional significance of the prolonged STAT1 signal, therefore, was explored by experimental interruption of tyrosine phosphorylation, either by premature withdrawal of the IFN-alpha or deferred addition of pharmacologically diverse antagonists: staurosporine (protein kinase inhibitor), phorbol 12-myristate 13-acetate (growth promoter), or aurintricarboxylic acid (ligand competitor). Results indicated that an approximately 18-hour period of continued STAT1 phosphorylation was associated with growth arrest, but that antiviral protection developed earlier. These differences provide novel evidence of a temporal dimension to IFN-alpha signal specificity and show that duration of STAT1 activation may be a critical variable in malignant cell responsiveness to antiproliferative therapy.

Molecular characterization of a cDNA that encodes six isoforms of a novel murine A kinase anchor protein

We have cloned cDNA that encodes six novel A kinase anchor proteins (collectively named AKAP-KL). AKAP-KL diversity is generated by alternative mRNA splicing and utilization of two translation initiation codons. AKAP-KL polypeptides are evident in lung, kidney, and cerebellum, but are absent from many tissues. Different isoforms predominate in different tissues. Thus, AKAP-KL expression is differentially regulated in vivo. All AKAP-KL isoforms contain a 20-residue domain that avidly binds (Kd approximately 10 nM) regulatory subunits (RII) of protein kinase AII and is highly homologous with the RII tethering site in neuronal AKAP75. The distribution of AKAP-KL is strikingly asymmetric (polarized) in situ. Anchor protein accumulates near the inner, apical surface of highly polarized epithelium in tubules of nephrons. Both RII and AKAP-KL are enriched at an intracellular site that lies just below the plasma membrane of alveolar epithelial cells in lung. AKAP-KL interacts with and modulates the structure of the actin cytoskeleton in transfected cells. We also demonstrate that the tethering domain of AKAP-KL avidly ligates RII subunits in intact cells. AKAP-KL may be involved in (a) establishing polarity in signaling systems and (b) physically and functionally integrating PKAII isoforms with downstream effectors to capture, amplify, and precisely focus diffuse, trans-cellular signals carried by cAMP.

The role of cyclin D3-dependent kinase in the phosphorylation of p130 in mouse BALB/c 3T3 fibroblasts

We have observed that cyclin D3-dependent kinase activity is increased in the late G1 phase in BALB/c 3T3 fibroblasts. The profile of cyclin D3-associated activity closely parallels that of cyclin D1, which is also induced after mitogenic stimulation of quiescent cells. These activities correlate with the appearance of hyperphosphorylated p130, an Rb family member important in regulating E2F-4 and E2F-5 activity in fibroblastic cells. We demonstrated, however, that only the cyclin D3 activity efficiently phosphorylated p130 in an in vitro kinase assay. This apparent specificity was further demonstrated by experiments which demonstrated that cyclin D3 was physically associated with p130 at the times when D3-dependent kinase activity and p130 hyperphosphorylation were observed. Examination of E2F by electrophoretic mobility shift assay revealed that E2F-4 DNA binding activity existed in a p130.E2F complex at times before D3-dependent kinase activity was apparent and in a free E2F-4 complex after D3 activity developed. Thus, our data suggest that cyclin D3 preferentially phosphorylates p130 and is thereby specifically targeted to overcoming growth-suppressive control mediated through p130 pathways.

Analysis of the four cox2 genes found in turnip (Brassica campestris, Brassicaceae) mitochondria

In turnip mitochondria the cox2 gene is partially contained within a 2-kb (kilobase) direct repeat that is the site of homologous recombination events that generate subgenomic molecules. Because of its partial presence within the direct repeat, the turnip cox2 gene exists in four genomic contexts, two on the master chromosome and one on each of the subgenomic circles. In order to gain information on the expression of plant mitochondrial genes that exist in multiple genomic contexts and on plant mitochondrial recombination repeats in general we have characterized all four copies of the turnip 2-kb repeat and the cox2 gene. DNA sequence analysis indicates that the turnip high-frequency recombination repeat is 2424 bp in length. All but the last 58 bp of the cox2 gene is contained within the repeat, resulting in the presence of two intact cox2 genes and two pseudogenes. An intact cox2 gene and a pseudogene are found on the master chromosome (218 kb). An intact cox2 gene is also found on the 135-kb subgenomic circle, while a pseudogene is found on the 83-kb subgenomic circle. The turnip cox2 gene is unique because it lacks the first or 5' intron and contains the second or 3' intron previously found only in the carrot. The turnip intron is a group II intron that has high similarity (94.7%) with the second intron in carrot; also it is in precisely the same position within the gene. Transcript mapping studies using locus-specific probes reveal stable transcripts from the intact genes but not from the pseudogenes.

Activation of the Jak2-Stat5 signaling pathway in Nb2 lymphoma cells by an anti-apoptotic agent, aurintricarboxylic acid

Biological effects of many hormones and cytokines are mediated through receptor-associated Jak tyrosine kinases and cytoplasmic Stat transcription factors, including critical physiological processes such as immunity, reproduction, and cell growth and differentiation. Pharmaceuticals that control Jak-Stat pathways are therefore of considerable interest. Here we demonstrate that a single Jak-Stat pathway can be activated by aurintricarboxylic acid (ATA), a negatively charged triphenylmethane derivative (475 Da) with anti-apoptotic properties. In prolactin (PRL)-dependent Nb2 lymphocytes, ATA sustained cell growth in the absence of hormone and mimicked rapid PRL-induced tyrosine phosphorylation of Jak2 and activation of Stat5a and Stat5b with tyrosine phosphorylation, heterodimerization, DNA binding, and induction of the Stat5-regulated pim-1 protooncogene. ATA also mimicked PRL activation of serine kinases ERK1 and ERK2. However, unlike PRL, ATA did not regulate Stat1 or Stat3. ATA also did not affect Jak3, which is activated in these cells by interleukin-2 family cytokines. Although the mechanism and specificity by which ATA activates Jak2, Stat5, and ERKs in Nb2 cells are still unclear, the present study demonstrates that certain hormone or cytokine effects on Jak-Stat pathways can be discretely imitated by a low molecular weight, non-peptide pharmaceutical. The results are also consistent with Stat5 involvement in lymphocyte growth and survival.

[Study of electron microscopy histochemistry and immunohistochemistry of extracellular matrix in adenoid cystic carcinoma]

In order to determine the character of the extracellular matrix in adenoid cystic carcinoma (ACC), 22 cases of ACC of salivary gland were examined by immunohistochemical methods and 4 cases were examined by electron microscopy histochemically. Immunohistochemistry, type IV collagen and fibronectin were more intensively localized in pseudocyst space and in extracellular matrix between tumor cells. Ultrastructural study showed that the pseudocystic cells had abundant rough endoplasmic reticulum and a well-developed Golgi apparatus, some cells had muscle microfilament. There were laminin, proteoglycan and collagen fibril in the pseudocyst space. The results indicated that type IV collagen and fibronectin were the important stromal component in ACC, which may be secreted by neoplasmic myoepithelial cells.