Harvesting and climate effects on organic matter characteristics in British Columbia coastal forests

As part of investigations into the effects of harvesting old-growth forest, we characterized carbon in five organic matter pools in eight forest chronosequences of coastal British Columbia. Each chronosequence comprised stands in four seral stages from regeneration (3-8 yr) to old-growth (>250 yr), with second-growth stands mostly of harvest origin. Stands were located in two biogeoclimatic subzones with contrasting climate (wetter, slightly cooler conditions on the west coast of Vancouver Island than on the east). Carbon concentrations in fine woody debris (FWD), forest floor (LFH), fine roots from LFH, and two water-floatable fractions from 10 to 30 cm mineral soil (MIN-ROOT, 2-8 mm and MIN-FLOAT, <2 mm) showed no significant effects due to climate, seral stage, or site. There were some significant differences in N concentrations, but none related to seral stage. Carbon-13 cross-polarization with magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectra with principal component analysis of relative areas also showed little harvesting effect, but greater variation related to input of coarse woody debris (CWD) vs. roots high in tannin. Overall, there tended to be more spectral features associated with wood and lignin in the west; whereas some MIN-ROOT samples from the drier east side had aromatic intensity attributed to charcoal. The minimal effects of one harvest on organic matter are most likely due to the large legacy effect; however, more intensive management will probably result in less CWD retention, less charcoal input, and less microsite variability in these pools of poorly decomposed organic matter.

[Analgesic effect induced by stimulation of rats brain with strong pulsed magnetic field: a preliminary study]

The Objective of this study was to determine whether stimulation on the brain of SD rats with strong pulsed magnetic field could produce analgesic effect. A stimulator of CADWELL (MES-10) was adopted in the study. The pain index used was the Tail Flick Latency (TFL) of rats. The stimulation parameters were: (1) the intensity percent (20%) and stimulation duration (7 min); (2) the intensity percent (30%) and stimulation duration (3 min). The results showed that the mean Acquired TFL change was 23% (P < 0.01) for the 20% intensity group, and 26% (P < 0.01) for the 30% intensity group.

CONCLUSION

These data indicate that the new method for analgesia is effective, and compared with other approaches to stimulation analgesia, this one is non-invasive, easy to operate, and less causative of discomfort.

Interaction of heterotrimeric G13 protein with an A-kinase-anchoring protein 110 (AKAP110) mediates cAMP-independent PKA activation

Heterotrimeric G proteins and protein kinase A (PKA) are two important transmitters that transfer signals from a wide variety of cell surface receptors to generate physiological responses. The established mechanism of PKA activation involves the activation of the Gs-cAMP pathway. Binding of cAMP to the regulatory subunit of PKA (rPKA) leads to a release and subsequent activation of a catalytic subunit of PKA (cPKA). Here, we report a novel mechanism of PKA stimulation that does not require cAMP. Using yeast two-hybrid screening, we found that the alpha subunit of G13 protein interacted with a member of the PKA-anchoring protein family, AKAP110. Using in vitro binding and coimmunoprecipitation assays, we have shown that only activated G alpha 13 binds to AKAP110, suggesting a potential role for AKAP110 as a G alpha subunit effector protein. Importantly, G alpha 13, AKAP110, rPKA, and cPKA can form a complex, as shown by coimmunoprecipitation. By characterizing the functional significance of the G alpha 13-AKAP110 interaction, we have found that G alpha 13 induced release of the cPKA from the AKAP110-rPKA complex, resulting in a cAMP-independent PKA activation. Finally, AKAP110 significantly potentiated G alpha 13-induced activation of PKA. Thus, AKAP110 provides a link between heterotrimeric G proteins and cAMP-independent activation of PKA.

Delivery of a hammerhead ribozyme specifically downregulates mutant type I collagen mRNA in a murine model of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a systemic heritable disorder of connective tissue, caused by a mutation in one of the genes for type I collagen, whose cardinal manifestation is bone fragility. Several studies have identified two molecular mechanisms of collagen type I defects. In chain exclusion, the mutant chain is not incorporated into the collagen triple helix, whereas in chain nonexclusion, it is. The dominant-negative effect of nonexcluded mutations must be taken into account in all strategies aimed at correcting the collagen defects in individuals affected with moderate or several OI. Herein, we describe the application of hammerhead ribozymes to selectively target the mutant minigene transcript expressed in a murine calvarial osteoblast cell line. Active and control inactive ribozymes were tested in vitro on both mutant and normal targets and in the minigene-expressing cell line. Active ribozyme cleaved its target with high efficiency and specificity in both a time-dependent and dose-dependent manner. After delivery of a ribozyme expression construct, intracellular ribozyme was detected, along with a relative reduction in mutant transcript level.

Cyclic AMP-independent activation of protein kinase A by vasoactive peptides

Protein kinase A (PKA) is an important effector enzyme commonly activated by cAMP. The present study focuses on our finding that the vasoactive peptide endothelin-1 (ET1), whose signaling is not coupled to cAMP production, stimulates PKA in two independent cellular models. Using an in vivo assay for PKA activity, we found that ET1 stimulated PKA in HeLa cells overexpressing ET1 receptors and in aortic smooth muscle cells expressing endogenous levels of ET1 receptors. In these cell models, ET1 did not stimulate cAMP production, indicating a novel mechanism for PKA activation. The ET1-induced activation of PKA was found to be dependent on the degradation of inhibitor of kappaB, which was previously reported to bind and inhibit PKA. ET1 potently stimulated the nuclear factor-kappaB pathway, and this effect was inhibited by overexpression of the inhibitor of kappaB dominant negative mutant (IkappaBalpham) and by treatment with the proteasome inhibitor MG-132. Importantly, IkappaBalpham and MG-132 had similar inhibitory effects on ET1-induced activation of PKA without affecting G(s)-mediated activation of PKA or ET1-induced phosphorylation of mitogen-activated protein kinase. Finally, another vasoactive peptide, angiotensin II, also stimulated PKA in a cAMP-independent manner in aortic smooth muscle cells. These findings suggest that cAMP-independent activation of PKA might be a general response to vasoactive peptides.

FTIR study of horseradish peroxidase in reverse micelles

Fourier transform infrared (FTIR) method was used to study the secondary structures of horseradish peroxidase (HRP) in aqueous solution and in reverse micelles for the first time. Results indicated that the structure of HRP in sodium bis(2-ethylhexy)sulfosuccinate (AOT) reverse micelles was close to that in aqueous solution. In cetyltrimethylammonium bromide (CTAB) and sodium dodecylfate (SDS) reverse micelles the position of some bands changed. Results indicated that the secondary structure had a close relationship with the surfactant species of the reverse micelles. Among the three types of reverse micelles, the system of AOT reverse micelles was probably the most beneficial reaction media to HRP.

The alphaVbeta6 integrin regulates its own expression with cell crowding: implications for tumour progression

Expression of the growth-promoting integrin alphavbeta6 in colon cancer cells induces gelatinase B secretion and activation, the inhibition of which abolishes alphavbeta6-mediated tumour cell growth within a collagen matrix. Herein, we show that high cell density selectively enhances alphavbeta6 expression in a protein kinase C (PKC)-dependent manner in preference to other beta integrin subunits, resulting in a marked increase in gelatinase B secretion as cells reach confluence. Moreover, PKC activity increases with cell confluence, and the rise in PKC activity is much greater for alphavbeta6-expressing cells than for colon cancer cells which lack alphavbeta6. We propose a self-perpetuating system of colon cancer progression in which the integrin alphavbeta6 provides a means of sustaining tumour cell proliferation. In this model, alphavbeta6 regulates its own expression via a PKC-mediated signalling pathway as tumour cells become crowded and quiescent. The alphavbeta6-mediated induction of gelatinase B secretion facilitates peri-cellular matrix degradation, which helps overcome crowding and restores cell proliferation.

The alphaVbeta6 integrin regulates its own expression with cell crowding: implications for tumour progression

Expression of the growth-promoting integrin alphavbeta6 in colon cancer cells induces gelatinase B secretion and activation, the inhibition of which abolishes alphavbeta6-mediated tumour cell growth within a collagen matrix. Herein, we show that high cell density selectively enhances alphavbeta6 expression in a protein kinase C (PKC)-dependent manner in preference to other beta integrin subunits, resulting in a marked increase in gelatinase B secretion as cells reach confluence. Moreover, PKC activity increases with cell confluence, and the rise in PKC activity is much greater for alphavbeta6-expressing cells than for colon cancer cells which lack alphavbeta6. We propose a self-perpetuating system of colon cancer progression in which the integrin alphavbeta6 provides a means of sustaining tumour cell proliferation. In this model, alphavbeta6 regulates its own expression via a PKC-mediated signalling pathway as tumour cells become crowded and quiescent. The alphavbeta6-mediated induction of gelatinase B secretion facilitates peri-cellular matrix degradation, which helps overcome crowding and restores cell proliferation.

Molecular rulers: an assessment of distance and spatial relationships of Src tyrosine kinase Sh2 and active site regions

The three-dimensional structures of the inactive conformations of Hck and Src, members of the Src protein-tyrosine kinase family, have recently been described. In both cases, the catalytic domain lies on the opposite face of the enzyme from the SH2 and SH3 domains. The active conformation of these enzymes has not yet been described. Given the known role of the SH2 and SH3 domains in promoting substrate binding, enzyme activation likely reorients the relative spatial arrangement between the SH2/SH3 domains and the active site region. We describe herein a series of "molecular rulers" and their use in assessing the topological and spatial relationships of the SH2 and active site regions of the Src protein-tyrosine kinase. These synthetic compounds contain sequences that are active site-directed (-Glu-Glu-Ile-Ile-(F(5))Phe-, where (F(5))Phe is pentafluorophenylalanine) and SH2-directed (-Tyr(P)-Glu-Glu-Ile-Glu-), separated by a sequence of variable length. The most potent bivalent compound, acetyl-Glu-Glu-Leu-Leu-(F(5))Phe-(GABA)(3)-Tyr(P)-Glu-Glu-Ile-Glu-amide (where GABA is gamma-aminobutyric acid), displays a >120-fold enhancement in inhibitory potency relative to the simple monovalent active site-directed species, acetyl-Glu-Glu-Leu-Leu-(F(5))Phe-amide. The short linker length (3 GABA residues) between the active site- and SH2-directed peptide fragments suggests that the corresponding domains on the Src kinase can assume a nearly contiguous spatial arrangement in the active form of the enzyme.

Clinical significance of magnetic resonance imaging of bone marrow in patients with leukemia

To investigate the clinical significance of magnetic resonance imaging (MRI) of bone marrow in patients with acute leukemia, the femoral and pelvic marrow were evaluated by using MRI with a T1-weighted spin-echo (SE) method and a short T1 inversion recovery (STIR) technique. Normal bone marrow examination was performed with coronal T1-weighted MRI of pelvis and femurs, and showed persistent red marrow. There was a bright signal of fatty marrow in the femoral epiphyses and apophyses. MRI pattern of bone marrow in the 54 cases of acute leukemia showed abnormal signal patterns of femoral and pelvic marrow: (1) grade I (n = 4), (2) grade II (n = 11), (3) grade III (n = 8), (4) grade IV (n = 17), and (5) graded V (n = 14). Leukemic cells had infiltration onseted by red marrow in adult patients with leukemia. The marrow of femur had infiltration from diaphysis to epiphysis, and to femoral head and greater trochanter. The lower grades (grade IV, V) of leukemic marrow supported the diagnosis of AML in MRI, which achieved higher complete remission. The adult patients with ALL had higher grades (grade I-III) in MRI. Our findings indicated that MRI of femoral marrow is an important tool for accurate diagnosis and management of patients with leukemia that may function as an adjunct to bone marrow aspiration and biopsy. The pattern of MRI in patients with newly diagnosed leukemia predicted the prognosis and CR of leukemia.

Regulator of G protein signaling RGS3T is localized to the nucleus and induces apoptosis

RGS3 belongs to a family of the regulators of G protein signaling (RGS). We previously demonstrated that cytosolic RGS3 translocates to the membrane to inhibit G(q/11) signaling (Dulin, N. O., Sorokin, A., Reed, E., Elliott, S., Kehrl, J., and Dunn, M. J. (1999) Mol. Cell. Biol. 19, 714-723). This study examines the properties of a recently identified truncated variant termed RGS3T. Both RGS3 and RGS3T bound to endogenous Galpha(q/11) and inhibited endothelin-1-stimulated calcium mobilization and mitogen-activated protein kinase activity to a similar extent. However, unlike cytosolically localized RGS3, RGS3T was found predominantly in the nucleus and partially in the plasma membrane. Furthermore, RGS3T, but not RGS3, caused cell rounding and membrane blebbing. Finally, 44% of RGS3T-transfected cells underwent apoptosis after serum withdrawal, which was significantly higher than that of RGS3-transfected cells (7%). Peptide sequence analysis revealed two potential nuclear localization signal (NLS) sequences in RGS3T. Further truncation of the RGS3T N terminus containing putative NLSs resulted in a significant reduction of nuclear versus cytoplasmic staining of the protein. Moreover, this truncated RGS3T no longer induced apoptosis. In summary, RGS3 and its truncated variant RGS3T are similar in their ability to inhibit G(q/11) signaling but are different in their intracellular distribution. These data suggest that, in addition to being a GTPase-activating protein, RGS3T has other distinct functions in the nucleus of the cell.

[Noninvasive estimation of tissue temperature in hyperthermia using diagnostic ultrasound]

Hyperthermia is one of the important techniques in tumor treatments. Temperature estimating and monitoring is the key technique in hyperthermia. In this paper, a new nonivasive temperature estimation method based on backscattered ultrasonic power is introduced. Compared with the techniques based on echo-shift and frequency-shift, this method has its advantage for application. The change of backscattered power caused by the temperature change is conspicuous and easy to measure. The new techniques and difficulties in this field are also addressed.

[Relationship between main vegetation types and climatic factors in Inner Mongolia]

The relationship between main vegetation types and climate factors in Inner Mongolia was analyzed by using up-to-date vegetation map, statistics, modeling and spatial simulation of regional climatic factors under the support of GIS. The feasible climatic range of spatial distribution of plant communities was derived from overlaying vegetation map and climate maps. The results showed that the vegetation distribution was obviously in accordance with climate. On the one hand, all the types, not only zonal vegetation, but also mountain, sandy land and low land communities changed gradually from east to west due to the distance to oceans, with a zonal differentiation, Precipitation played an important role in determining this regulation. On the other hand, latitudinal replacement of plant communities occurred with the change of temperature from north to south. In addition, temperature was also the key factor controlling the spatial distribution of vegetation types, such as meadow, steppe, shrub and low land communities on the east and west sides of Daxinganling Mountains.

[A study on family aggregation of type 2 diabetes mellitus]

OBJECTIVE

To estimate the genetic susceptibility and its relative risk (RR) in the first degree relatives of type 2 diabetes mellitus (DM) through family aggregation analysis.

METHODS

A population-based case-control study including 654 pedigrees (363 index cases and 291 controls) was carried out.

RESULTS

The prevalence rate in the first degree relatives of DM probands was 3.94%, significantly higher than that in the controls (1.09%), with a relative risk of 3.62 (chi(2) = 36.5, P < 0.001). The RRs in different consanguineal relatives were all higher than 3.0. The younger was the probands at diagnosis for DM, the higher its prevalence rates and RRs among their relatives was and the more likelihood that more than one case of DM occurred in them.

CONCLUSION

Significant family aggregation and higher genetic susceptibility were found in the first degree relatives of DM, on whom prevention and treatment for DM should be focused.

The alpha v beta 6 integrin induces gelatinase B secretion in colon cancer cells

In human cancers, the co-operative role between cell-adhesion receptors and proteases capable of degrading matrix barriers remains poorly understood. We have previously reported that the epithelium-restricted integrin alpha(v)beta6 becomes highly expressed in colon cancer compared with normal mucosa and that heterologous expression of alpha(v)beta6 in colon cancer cells is associated with enhanced cell growth. Herein, we report that alpha(v)beta6 expression in colon cancer cells leads to a relative increase in secretion of the matrix metalloproteinase gelatinase B over its respective inhibitor and that this secretion parallels the level of cell-surface beta6 expression. The alpha(v)beta6-mediated gelatinase B secretion is associated with increased proteolysis of denatured collagen at the cell surface, and inactivation of gelatinase B in beta6-expressing tumour cells inhibits cell spreading and proliferation within 3-dimensional collagen matrices. Our findings suggest that alpha(v)beta6-mediated gelatinase B secretion is important in the progression of human colon cancer.

The alpha v beta 6 integrin induces gelatinase B secretion in colon cancer cells

In human cancers, the co-operative role between cell-adhesion receptors and proteases capable of degrading matrix barriers remains poorly understood. We have previously reported that the epithelium-restricted integrin alpha(v)beta6 becomes highly expressed in colon cancer compared with normal mucosa and that heterologous expression of alpha(v)beta6 in colon cancer cells is associated with enhanced cell growth. Herein, we report that alpha(v)beta6 expression in colon cancer cells leads to a relative increase in secretion of the matrix metalloproteinase gelatinase B over its respective inhibitor and that this secretion parallels the level of cell-surface beta6 expression. The alpha(v)beta6-mediated gelatinase B secretion is associated with increased proteolysis of denatured collagen at the cell surface, and inactivation of gelatinase B in beta6-expressing tumour cells inhibits cell spreading and proliferation within 3-dimensional collagen matrices. Our findings suggest that alpha(v)beta6-mediated gelatinase B secretion is important in the progression of human colon cancer.

[Clinical observation of forty cases in adolescent dysmenorrhea treated by traditional Chinese medicine]

OBJECTIVE

To observe the therapeutic effect of Tongjing powder (TP) and understand the change in pathophysiology of dysmenorrhea, the blood flow parameters of uterine arteries and hemorheological data before and after the TP administration.

METHODS

The blood of both uterine arteries of patients was examined by color doppler flow imaging. The hemorheological data was examined by conical viscosimeter. The two groups were compared with each other.

RESULTS

Pulsation index (PI), resistance index (RI), systolic peak value/diastolic peak value (A/B value) of dysmenorrhea patients and hemorheological data except erythrocyte sedimentation rate of dysmenorrhea patients were significantly higher than the normal control group. After treating with TP, no difference existed between two groups.

CONCLUSIONS

The blood of dysmenorrhea patients appear to be viscous and adhesive, TP can improve the state of blood circulation and treat the dysmenorrhea effectively.

Integrin-mediated signalling of gelatinase B secretion in colon cancer cells

The progression of colon cancer has been linked to both cell adhesion molecules called integrins and matrix-degrading enzymes called metalloproteinases. Herein we report that the alpha v beta 6 integrin expressed in colon cancer cells induces gelatinase B secretion through the C-terminal cytoplasmic extension unique to the beta 6 integrin subunit, and that this ligand-independent event involves activation of the protein-kinase-C pathway.

Genotoxicity and chronic health effects of automobile exhaust: a study on the traffic policemen in the city of Lanzhou

A study on the health and genotoxic effects of occupational exposure to automobile exhaust was carried out among traffic policemen in Lanzhou (China) in 1996. A total of 78 traffic policemen working in the field was the exposed group, and 57 household register policemen working in the office was the control group. The health effects were evaluated by health questionnaires. Significant differences were observed between the exposed and control groups with respect to the morbidity of rhinitis, pharyngitis, trachoma, syndrome of neurasthenia and joint pain, apart from disorders in the digestive system. The percentage of rhinitis and pharyngitis obtained in the two groups was significantly higher among the smokers than among the nonsmokers. The frequencies of micronuclei (MN) and sister-chromatid exchanges (SCEs) were measured in peripheral blood lymphocytes from the two groups of volunteers. Compared with the control group, statistically significant increases of MN and SCE were found for the exposed group. The increase in the induction of MN and SCE among the traffic policemen and household register policemen is enhanced further by smoking.

[Intracardiac operations performed in beating heart through mini-thoracotomy in 34 patients]

OBJECTIVE

To introduce the technique of intracardiac operations performed in beating heart through mini-thoracotomy.

METHOD

>From March 1995 to June 1997, intracardiac operations were performed in beating heart through right subaxillary anterolateral mini-thoracotomy with normothermic extracorporeal circulation in 34 patients. 16 patients had atrial septal defect, 14 ventricular septal defect, 2 mitral insufficiency, 1 right coronary artery-right ventricular fistula, and 1 Ebstein's anomaly.

RESULT

The mean cardiopulmonary bypass time was 22.54 minutes. There were no embolism, arrhythmia and cerebral complications. Postoperative hospital stay was 8.0 +/- 2.2 days. All the patients had no heart murmur and residual shunt, and enjoyed a full range of physical activities in a follow-up of 2 to 26 months.

CONCLUSION

Intracardiac operations performed in beating heart through right subaxillary anterolateral mini-thoracotomy appears to be less invasive, simple, safe and cosmetic.

[Cloning and expressing of HCV NS5 partial gene and dynamic changes of anti-NS5]

OBJECTIVE

To study antigenicity of HCV NS5 protein and dynamic changes of anti-NS5 in post-transfusion hepatitis C (PT-HC).

METHODS

Epitopes of HCV NS5 protein were analyzed by Goldkey Program. NS5 gene fragment was amplified by reverse transcription and polymerize chain reaction (RT-PCR) from sera of PT-HC patients. Sequence analysis was performed, and recombinant strain was constructed. Series sera from PT-HC were detected for anti-NS5, ALT and HCV RNA.

RESULTS

The homology of nucleotide and amino acid with genotype II in the same region was 91.8% and 92.4%, respectively. SDS-PAGE analysis showed an expressing band around 50 kD, the fusion protein represented about 21.4% of total bacterial protein. Western blot result proved the expressing band could specifically react with sera from hepatitis C patients. Detection results of series blood samples from PT-HC showed that the antibody against NS5 appeared relatively late, the positive conversion time was 182.9 +/- 168.5 day. Dynamic changes of anti-NS5 were correlated with serum ALT in most cases. The types of dynamic change of anti-NS5 were passing positive; intermittent positive; persistent positive, and persistent negative in two years.

CONCLUSION

Antibody against NS5 may reflect the disease activity to some extent. It appears relatively late, and is of no value in early stage diagnosis.

Protein kinase inhibitors: the tyrosine-specific protein kinases

Inhibitors for tyrosine-specific protein kinases ultimately may constitute a novel family of medicinally active agents. Unfortunately, the challenges associated with the acquisition of inhibitors for these enzyme targets are unlike any that have ever been encountered in medicinal chemistry. Protein kinases pose a variety of obstacles in regard to inhibitor design, nearly all of which deal with, in one fashion or another, the issue of specificity. The protein kinase family is extraordinarily large, with estimates that the human genome codes for as many as 2000 protein kinases. Furthermore, inhibitors that are directed to the ATP-binding sites of these enzymes must contend with the presence of a large number of other ATP-utilizing proteins and, in addition, must compete with the high intracellular concentrations of ATP. Although specificity ultimately may prove to be less of a concern with peptide-based inhibitors, these agents neither are readily bioavailable nor do they bind with the requisite affinity to the protein-binding domains of protein kinases. In the face of these challenges, an enormous number of inhibitors have been synthesized and evaluated for the tyrosine-specific protein kinases. The advantages and disadvantages associated with inhibitors that are targeted to the ATP-binding site, the protein-binding site, and nonactive site regions required for appropriate subcellular localization are discussed. The handful of tyrosine-specific protein kinases that have been selected as targets to date and their roles in various disease processes are described as well.

Protease profiles of cells isolated from regenerative membranes are associated with clinical outcomes

Guided tissue regeneration (GTR) is a clinical procedure used to restore the attachment apparatus of periodontally diseased teeth. Guided bone regeneration (GBR) is a similar procedure used to augment bone of edentulous ridges. Both therapies enhance the ability of regenerative cells to repopulate wounds by using expanded polytetrafluoroethylene (ePTFE) membranes to exclude gingival fibroblasts and keratinocytes from the healing site. Cells were isolated from 12 membranes used in each procedure and screened for the ability to form mineralized nodules in vitro, a property of cells with osteogenic potential. Using zymography and reverse zymography, low-passage isolates of cells which formed nodules were examined for the expression of gelatinolytic and caseinolytic proteases as well as for proteinase inhibitors. These molecular data were then compared with clinical outcomes for each procedure. Cells isolated from regenerative membranes exhibited variable expression of 72 kDa gelatinase, fibroblast collagenase, stromelysin, tissue inhibitor of metalloproteinases (TIMP-1), and other unidentified proteases. The greatest proportion of clinical failures was associated with GTR therapy. Cells from GTR membranes which did not exhibit gains in clinical attachment often exhibited aberrant proteinase profiles. When compared with cells from GBR procedures, most cells from GTR procedures also secreted lower amounts of TIMP-1. The study shows that cells isolated from regenerative procedures produce degradative enzymes in vitro which may be related to the success or failure of the regenerative process in vivo. Generally, cells from unsuccessful GTR procedures produced low molecular weight gelatinases not associated with cells from successful cases.

The high affinity heparin-binding domain and the V region of fibronectin mediate invasion of human oral squamous cell carcinoma cells in vitro

Fibronectin is an extracellular matrix molecule composed of repeating subunits that create functional domains. These domains contain multiple binding sites for heparin and for various cell-surface receptors that modulate cell function. To examine the role that the high affinity heparin-binding region and the alternatively spliced V region of fibronectin play in tumor invasion, we expressed and purified four complementary recombinant fibronectin proteins. These proteins either included or excluded the alternatively spliced V region and contained either a mutated, non-functional high affinity heparin-binding domain (Hep-) or an unmutated heparin-binding domain (Hep+). Cultured oral squamous cell carcinoma cells were assayed for invasion into a Matrigel/collagen matrix supplemented with these four purified recombinant proteins, and for spreading and motility on plastic. Increased invasion was observed in gels supplemented with the V-Hep+ protein when compared with the V-Hep- protein. Inclusion of the V region in the proteins enhanced the invasion and migration associated with both Hep+ and Hep- proteins, whereas cell spreading was enhanced with the Hep+ recombinant proteins. These data demonstrate that both the high affinity heparin-binding domain and the V region of fibronectin play important roles in invasion, motility, and spreading of oral squamous cell carcinoma cells.

[Character of emergence for the seeds of Ephedra sinica]

The experimental results on the germinating of Ephedra sinica seeds and sowing show: the seeds of E. sinica are not sensitive to illumination, but very sensitive to humidity; the effects of soil, the depth of sowing and irrigation on emergence are very notable, but not remarkable to covering which can be used to prevent measure.

[A prospective study on transfusion-related hepatitis C virus infection]

64 cases of blood recipients were followed-up for 6 months to study infection of hepatitis C virus. The infection rate of hepatitis C virus was 18.75% in total, including 8 cases of post-transfusion hepatitis C (PT-HC), 1 case of subclinical PT-HC, and 3 cases of anti-HCV sero conversion only. The time of initial ALT abnormality and anti-HCV sero conversion were 28 to 91 (51.9 +/- 20.9) days and 23 to 76 (42.4 +/- 15.9) days after blood transfusion respectively. There were 2 cases with cytomeglovirus infection and another 5 cases with unknown infectious agent were found in this study.

Structure and spatial expression of the Manduca sexta MSCP14.6 cuticle gene

The genomic and cDNA sequences of the MSCP14.6 gene section, which encodes a Manduca sexta cuticle protein, have been determined. The genomic sequence presented here includes 1428 N of 5' flanking DNA, 1587 N of transcribed DNA, and 465 N of 3' flanking DNA. The intron/exon boundaries mapped by comparison of these sequences were confirmed by primer extension and SI nuclease mapping. Prior work showed that the RNA produced by this gene is regulated both temporally and spatially during larval, pupal, and adult development, and also showed that both 20-hydroxyecdysone (20E) and juvenile hormone (JH) are important in controlling the amount of RNA present in the epidermis (Riddiford et al., 1986). In situ hybridizations show that MSCP14.6 is expressed throughout the epidermis in larvae and is spatially restricted in pharate pupal and pharate adult stages. The results presented here delimiting the transcription unit and 5' flanking DNA of the MSCP14.6 gene will facilitate further research to determine the DNA elements necessary for regulation of gene expression.

Nonphosphorylatable tyrosine surrogates. Implications for protein kinase inhibitor design

Tyrosine-specific protein kinases are known to utilize short synthetic tyrosine-containing peptides as substrates and, as a consequence, a number of inhibitory peptides have been prepared by replacing the tyrosine moiety in these peptides with a nonphosphorylatable phenylalanine residue. Unfortunately, the inhibitory efficacy of these phenylalanine-based peptides is often disappointing. These results demonstrate the need for nonphosphorylatable tyrosine surrogates that enhance enzyme affinity. As a consequence, we prepared nearly two dozen different phenethylamine derivatives, attached them to the C terminus of an active site-directed peptide (Glu-Glu-Leu-Leu), and examined their effectiveness as inhibitors of pp60(c-)src. Three derivatives exhibit enhanced inhibitory activity (relative to phenethylamine), including para-substituted sulfonamide and guanidino analogs as well as a pentafluoro-containing species. The para-sulfonamide derivative was selected for further study and was found to function as a competitive inhibitor versus variable peptide substrate and as a noncompetitive inhibitor versus variable ATP. In short, the enhanced inhibitory activity of the sulfonamide derivative is not due to the association of this moiety with the ATP binding site. Furthermore, peptides containing the para-guanidino and pentafluoro derivatives of phenylalanine were prepared. These species also display enhanced inhibitory activity toward pp60(c-)src relative to the corresponding phenylalanine-based peptide.

Exposure of periodontal ligament cells to methyl mercaptan reduces intracellular pH and inhibits cell migration

Volatile sulfur compounds such as hydrogen sulfide and methyl mercaptan have been associated with adult periodontitis as well as with healing surgical wounds. To examine the effects of these compounds on the periodontium, we assayed periodontal ligament (PDL) cells for changes in intracellular pH, total protein, and cell migration following chronic exposure to CH3SH. Intracellular pH was quantitated by fluorescence measurements of cells loaded with BCECF, a pH-sensitive dye. Data show that 48-hour exposure to mercaptan lowered resting intracellular pH but did not consistently alter activity of the Na/H exchanger. This effect was seen in PDL cells from three different patients. Lowered pH was accompanied by decreases in both total protein and mature alpha 1 and alpha 2 chains of type I collagen. Since reductions in intracellular pH and total protein have been associated with inhibition of cell motility, migration was quantitated by sequential computer imaging, which measured the increase in size of plated cell circles at different times of migration. Incubation of PDL cells in pH 7.4 and 6.6 buffers reversibly altered intracellular pH. Migration was reversibly inhibited in pH 6.8 buffer. Exposure to CH3SH reduced intracellular pH in pH 7.4 buffer and in three independent assays inhibited enlargement of cell circles in pH 7.4 medium. These effects were therefore not related to alterations of extracellular pH, which remained at 7.4. The results support the hypothesis that gases such as methyl mercaptan may play a role in both surgical wound healing and periodontal disease by adversely affecting cell function and suggest that alterations in intracellular pH may be part of the mechanism for these changes.

Hepatitis C virus replication in hepatocellular carcinoma

Hepatitis C virus (HCV) replication is reported in both tumour and non-tumour tissue in a case of hepatocellular carcinoma. Viral replication was established by showing the presence of minus strand HCV RNA by PCR amplification, after excluding residual reverse transcriptase activity of Taq polymerase. No minus strand was found in serum derived virion RNA. PCR amplified products from both tumour and non-tumour parenchyma were sequenced in the 5' non-coding region and shown to be identical. The genotype of this Indonesian patient was found to be 1b (or II), the most prevalent type in the Far East.

Differential staining of DNA strand breaks in dying cells by non-radioactive in situ nick translation

Various lines of evidence indicate the involvement of DNA strand breaks (DSB) in the regulation of physiological states of cells, especially in cell death. Currently, cell death is divided into two categories, apoptosis and necrosis. As lysosomal integrity is maintained in apoptosis, while disrupted in necrosis, it is possible to assume that necrotic chromatin is exposed to digestion by various lysosomal enzymes. We have therefore investigated whether apoptotic DSB and necrotic DSB can be discriminated by in situ nick translation (INT) under various conditions of protease pretreatment. Used models of apoptosis and necrosis were the rat thymus with an intraperitoneal injection of hydrocortisone (10 mg/100 g body weight (b.w.)) and rat liver with an intraperitoneal injection of CCl4 (100 microliters/g b.w.), respectively. As results, we found that necrotic DSB was readily detected by INT without protein digestion, whereas apoptotic ones were not. These results indicate that the environment around DSB and/or the nature of DSB in apoptosis differs from that of necrosis, and that INT is a convenient molecular histochemical tool to discriminate both types of cell death in frozen sections.

Hepatitis C virus type I(1a) in northern China

Twenty-four patients with hepatitis C virus (HCV) antibody from the Chinese North Western province of Jilin were further analysed by the immunoblot assay-2 (RIBA-2), reverse transcription-polymerase chain reaction (RT-PCR) for serum HCV RNA detection, and direct sequence-genotyping. Good concordance was found between the original second generation HCV antibody ELISA, RIBA-2, and serum HCV RNA. The occurrence of genotype I (1a), a genotype not previously reported in China, is described in 5(20.8%) of 24 cases, in association with genotypes II(1b) and III(2a) which were found in 16(66.7%) and 3(12.5%) of 24 cases, respectively. Imported blood products were unlikely to be the source of infection with genotype I (1a) but could not be definitively ruled out.

The extraordinary active site substrate specificity of pp60c-src. A multiple specificity protein kinase

We report the first active site substrate specificity analysis of a tyrosine-specific protein kinase, namely pp60c-src. Like the cAMP-dependent protein kinase and protein kinase C, pp60c-src will phosphorylate an assortment of achiral residues attached to active site-directed peptides. Furthermore, pp60c-src phosphorylates both aromatic and aliphatic alcohols. However, the substrate specificity of pp60c-src is much broader than that of the two previously examined serine/threonine-specific protein kinases. We have previously shown that both the cAMP-dependent protein kinase and protein kinase C will utilize a wide array of non-amino acid residues as substrates, as long as the distance between the hydroxyl moiety and the adjacent peptide backbone is comparable with that present in serine and threonine (Kwon, Y.-G., Mendelow, M., and Lawrence, D. S. (1994) J. Biol. Chem. 269, 4839-4844). In marked contrast, pp60c-src does not discriminate against substrates on the basis of chain length, catalyzing the phosphorylation of residues that contain anywhere from 2-12 carbons between the alcohol functional group and the adjacent peptide bond. In addition, pp60c-src phosphorylates L-serine in an active site-directed peptide. The possible structural basis for the multiple specificity of pp60c-src is discussed. Finally, the active site specificity of pp60c-src is not just limited to L-amino acid residues, but also extends into the realm of D-amino acids as well.

Laparoscopic exploration of intra- and extrahepatic bile ducts and T-tube drainage

Laparoscopic cholecystectomy (LC) has rapidly become the procedure of choice for the management of patients with gall-bladder stones. This contrasts with patients who have common bile duct and intrahepatic duct stones who still usually need an open operation. On the basis of experience of a number of LC by one surgeon and animal experiments, we have completed laparoscopic exploration of both intra- and extrahepatic ducts and T-tube drainage of 57 patients with intra- and extrahepatic bile duct calculi over 13 months during 1992-1993 with satisfactory results. The average operating time was 150 min, with a range of 100 to 220 min. Most patients were mobile and on oral fluids within 24 h postoperative. Average hospital stay was 4 days. Retained stones were found via T-tube cholangiography in four patients (7%) and for each patient these were removed by fibre-optic choledochoscope 2 weeks postoperatively. Laparoscopic exploration of intra- and extrahepatic bile ducts is achievable by experienced surgeons and may be particularly helpful for patients who are not a good operative risk.