[Effects of low temperature storage on DNA migration assayed by single cell gel electrophoresis]

V79 cells treated with potassium dichromate and control cells were stored at 4 degrees C, -20 degrees C, -80 degrees C and -196 degrees C. Single cell gel electrophoresis (SCGE) was carried out after preserving cells for 0, 4, 24, 48 and 168 hours. The results showed that there was no difference on DNA migration between cells processing immediately after trypsinization and cells preserving for 24 h at different low temperatures. Longer storage (48 h or 168 h) resulted in a significant increase in the length of DNA migration and decrease in cell viability. The results suggested that 4 degrees C is more convenient for less than 24 h storage without influence on DNA migration and -80 degrees C is better for longer storage to minimize the influence on DNA migration.

Genetic engineering of proteins with cell membrane permeability

The discovery of methods for generating proteins with inherent cell membrane-translocating activity will expand our ability to study and manipulate various intracellular processes in living systems. We report a method to engineer proteins with cell-membrane permeability. After a 12-amino acid residue membrane-translocating sequence (MTS) was fused to the C-terminus of glutathione S-transferase (GST), the resultant GST-MTS fusion proteins were efficiently imported into NIH 3T3 fibroblasts and other cells. To explore the applicability of this nondestructive import method to the study of intracellular processes, a 41-kDa GST-Grb2SH2-MTS fusion protein containing the Grb2 SH2 domain was tested for its effect on the epidermal growth factor (EGF)-stimulated signaling pathway. This fusion protein entered cells, formed a complex with phosphorylated EGF receptor (EGFR), and inhibited EGF-induced EGFR-Grb2 association and mitogen-activated protein kinase activation.

[The influence of electroacupuncture with different frequencies on the discharges of neurons in rostral ventromedial medulla on rats]

The experiments were carried out on rats, anesthetized with urethan and paralyed with tubocuraine. Stainless steel needles were inserted into bilateral "Zusanli" points. The unit discharges of RVM neurons were recorded extracellalarly by microelectrode. The searching of nociceptive neurons and processing of data were operated automatically by a real time control system. The results were as follow: 1. The pain response of excitatory neurons could be inhibited by 2 Hz EA (n = 15/22, P < 0.01), the mean inhibition rate was 32.40%. 2. The inhibitory effects of 2 Hz were completely blocked by naloxone pretreated (n = 5/5, P < 0.01). 3. The pain response of excitatory neurons could be inhibited by 10 Hz EA(n = 10/13, P < 0.01), the mean inhibition rate was 49.06%. 4. The inhibitory effects of 10 Hz EA were partially blocked by naloxone pretreated (n = 5/5, P < 0.01). 5. Both 2 Hz and 10 Hz EA could enhance the spontaneous discharges of excitatory neurons in RVM, and the percentage of change in the frequency was 62.45% and 112.02% respectively. 6. Neither 2 Hz nor 10 Hz EA could obviously influence the spontaneous activity of inhibitory neurons in RVM. The results suggest that both 2 Hz and 10 Hz EA could activate excitatory neurons in RVM, which may suppress nociceptive transmission via opioid mechanism.

[Sequencing the 16S rDNA of representative strain of new rhizobial group and determining of its phylogenetic relationship]

The full-length 16S rDNA sequence of representative strain SH2672 were sequenced by the dideoxy-mediated chain-termination method. This sequence was compared with that of type strains of all known rhizobia and related bacteria. An unrooted phylogenetic tree was produced. In this tree, strain SH2672, Mesorhizobium loti, M. huakuii, M. tianshanense, M. mediterraneum, and M. ciceri constituted a branch. Within this branch, the similarity values of 16S rDNA sequences between strain SH2672 and M. loti, M. huakuii, M. tianshanense, M. mediterraneum and M. ciceri were 96.3%, 96.4%, 97.2%, 95.1% and 95.6% respectively. All similarity values was more than 95%, this indicated that these species should belong to the same genus. The values of DNA-DNA homology between type strains of these species were less than 70%, which showed that strain SH2672 (representative strain of new group) represented a new rhizobial species.

[Studies on the relationship between purified alpha class glutathione S-transferase (GST-alpha) and hepatocellular damage]

Using our ELISA kit for GST-alpha, we tested the serum GST-alpha levels of patients with hepatitis A, acute hepatitis B (HB), chronic active HB, chronic persistent HB and liver cirrhosis. Serum GST-alpha levels in all these groups of patients were significantly higher than those in the controls (P < 0.01). Serum GST-alpha levels was closely (P < 0.01) correlated with serum alanine transaminase (ALT) levels in various groups of patients except chronic persistant HB. The combined application of the two markers, GST-alpha and ALT, raised the sensitivity of detection for liver diseases. In detection of chronic persistent HB patients, the GST-alpha marker was more sensitive than ALT (P < 0.01). The follow-up data of GST-alpha and ALT markers in serum showed that the GST-alpha level could reflect the clinical progression of liver disease more exactly as observed in 79 liver cancer patients in then GST-alpha and ALT positive rate were 81% and 61% respectively (P < 0.01). In 30 persons with positive HBsAg, the positive rates of GST-alpha and ALT were 70% and 37%, respectively. These results indicated that, (1) the detection of GST-alpha combined with ALT was capable of increasing the sensitivity for recognizing hepatocellular damage; (2) the elevation of serum GST-alpha level mainly resulted from the increased expression of GST-alpha in liver cells during hepatocarcinogenesis, thus, the GST-alpha is thought to be a tumor marker for liver cancer; (3) GST-alpha measurement offers advantage over ALT for the detection of minor degree of hepatocellular damages. GST-alpha may act as an early, sensitive and specific enzyme marker.

[Comparison of pharmacological studies on ootheca Mantidis]

The pharmacological effects of three species of Ootheca Mantidises were compared. The results indicate that Tenodera sinensis can increase the index of testis and thymus gland, and has an antidiuretic effect in mice; Statilia maculate can prolong the swimming time and ordinary pressing anoxia, increase the index of spleen and thymus gland, raise the temperature in mice, decrease the content of LPO in liver of the hypercholesteremia rats, and has an antidiuretic effect; Hierodula patellifera can increase the index of testis and thymus gland, raise the temperature in mice, and decrease the content of LPO in liver of the hypercholesteremia rets. The LD50 of the three species of Ootheca Mantidises are all over 320 g/kg.

Heat shock protein 70 expression in native and heterotopically transplanted rat hearts

Heat shock proteins (hsp) are intracellular proteins that are rapidly synthesized in response to a variety of stress factors. Recent studies in rats have shown that these proteins can elicit a lymphocyte response during cardiac allograft rejection. We studied the expression of the inducible (i) and constitutive (c) forms of hsp70 in rat cardiac allograft and isograft recipients to evaluate their utility as indicators of transplant rejection. Heterotopic transplantation of rat hearts was performed, using Lewis to Lewis isografts and ACI to Lewis allografts. Sham-operated rats were used as controls. Transplanted isograft, allograft, and native hearts of the transplant recipients and their livers and spleens were harvested at 5 days posttransplant and analyzed for hsp70 (i) and (c) expression by Western blots. Seven animals were studied in each group. Isografts at 3 and 60 days and allografts at 8 days were also studied. Quantification of band densities was carried out by laser densitometry. Physiological function of the native hearts of the transplant recipients was studied using Langendorff preparations. High levels of hsp70 (i) were noted in the transplanted and native hearts of the transplant recipients but not in their livers or spleens or in the hearts of the sham-operated control animals. Myocardial function of the native hearts of the transplant recipients was not significantly different from that of the controls. Significantly higher levels of hsp70 (c) were present in mild and severely rejecting allografts compared with controls and nonrejecting isografts. In the rat model of heterotopic cardiac transplantation, high levels of hsp70 (i) in the native hearts of the allograft and isograft recipients suggest a transplant-related, cardiac-specific stress process, not previously described. Heat shock protein 70 (c) expression is significantly increased during early and late allograft rejection and may serve as an indicator of transplant rejection.

Regulation of AP-3 function by inositides. Identification of phosphatidylinositol 3,4,5-trisphosphate as a potent ligand

As part of the growing effort to understand the role inositol phosphates and inositol lipids play in the regulation of vesicle traffic within nerve terminals, we determined whether or not the synapse-specific clathrin assembly protein AP-3 can interact with inositol lipids. We found that soluble dioctanoyl-phosphatidylinositol 3,4,5-trisphosphate (DiC8PtdIns(3,4, 5)P3) was only 7.5-fold weaker a ligand than D-myo-inositol hexakisphosphate in assays that measured the displacement of D-myo-[3H]inositol hexakisphosphate. In functional assays we found that both of these ligands inhibited clathrin assembly, but DiC8-PtdIns(3,4,5)P3 was more potent and exhibited a larger maximal effect. We also examined the structural features of DiC8-PtdIns(3,4, 5)P3 that establish specificity. Dioctanoyl-phosphatidylinositol 3, 4-bisphosphate, which does not have a 5-phosphate, and 4, 5-O-bisphosphoryl-D-myo-inosityl 1-O-(1, 2-O-diundecyl)-sn-3-glycerylphosphate, which does not have a 3-phosphate, were, respectively, 2-fold and 4-fold less potent than DiC8-PtdIns(3,4,5)P3 as inhibitors of clathrin assembly. Deacylation of DiC8-PtdIns(3,4,5)P3 reduced its affinity for AP-3 almost 20-fold, and also dramatically lowered its ability to inhibit clathrin assembly. The deacylated products of the soluble derivatives of phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 4, 5-bisphosphate were both not significant inhibitors of clathrin assembly. It therefore appears that the interactions of inositides with AP-3 should not be considered simply in terms of electrostatic effects of the highly charged phosphate groups. Ligand specificity appears also to be mediated by hydrophobic interactions with the fatty-acyl chains of the inositol lipids.

Properties of the inositol 3,4,5,6-tetrakisphosphate 1-kinase purified from rat liver. Regulation of enzyme activity by inositol 1,3,4-trisphosphate

Inositol 3,4,5,6-tetrakisphosphate is a novel intracellular signal that regulates calcium-dependent chloride conductance (Xie, W., Kaetzel, M. A., Bruzik, K. S., Dedman, J. R., Shears, S. B., and Nelson, D. J. (1996) J. Biol. Chem. 271, 14092-14097). The molecular mechanisms that regulate the cellular levels of this signal are not characterized. To pursue this problem we have now studied the 1-kinase that deactivates inositol 3,4,5,6-tetrakisphosphate. The enzyme was purified from rat liver 1600-fold with a 1% yield. The native molecular mass was determined to be 46 kDa by gel filtration. The Km values for inositol 3,4,5,6-tetrakisphosphate and ATP were 0. 3 and 10.6 microM, respectively. The kinase was unaffected by either protein kinase A or protein kinase C. Increases in Ca2+ concentration from 0.1 to 1-2 microM inhibited activity by 10-20%. Most importantly, inositol 1,3,4-trisphosphate was shown to be a potent (Ki = 0.2 microM), specific, and competitive inhibitor of the 1-kinase. Our new kinetic data show that typical receptor-dependent adjustments in cellular levels of inositol 1,3,4-trisphosphate provide a mechanism by which the concentration of inositol 3,4,5,6-tetrakisphosphate is dependent on changes in phospholipase C activity. These conclusions also provide a new perspective to our understanding of the physiological importance of the pathway of inositol phosphate turnover initiated by the inositol 1,4, 5-trisphosphate 3-kinase.

Increased activity of small GTP-binding protein-dependent phospholipase D during differentiation in human promyelocytic leukemic HL60 cells

In response to dibutyryl cyclic AMP (dbcAMP) and all-trans retinoic acid, human promyelocytic leukemic HL60 cells differentiate into granulocyte-like cells. In cell lysate and in vitro reconstitution system, phospholipase D (PLD) activity in response to guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) was up-regulated by dbcAMP or all-trans retinoic acid treatment. In the present study, the mechanism(s) for increased PLD activity during differentiation was examined. Western blot analysis revealed that the contents of ADP-ribosylation factor, Rac2, and Cdc42Hs but not RhoA and Rac1 in the cytosolic fraction were elevated during differentiation. However, the cytosolic fraction from undifferentiated cells was almost equally potent as the cytosolic fraction from differentiated cells in the ability to stimulate membrane PLD activity. It was shown that the GTPgammaS-dependent PLD activity in membranes from differentiated cells was much higher than that in membranes from undifferentiated cells, suggesting that the increased PLD activity during differentiation was due to alterations in some membrane component(s). Clostridium botulinum ADP-ribosyltransferase C3 and C. difficile toxin B, which are known as inhibitors of RhoA and Rho family proteins, respectively, effectively suppressed PLD activity in membranes from differentiated cells. In fact, the amount of membrane-associated RhoA was increased during differentiation. Furthermore, the extent of GTPgammaS-dependent PLD activity partially purified from membranes from differentiated cells was greater than that from membranes from undifferentiated cells in the presence of recombinant ADP-ribosylation factor 1. The PLD (hPLD1) mRNA level was observed to be up-regulated during differentiation, as inferred by reverse transcription-polymerase chain reaction. Our results suggest the possibility that the increased Rho proteins in membranes and the changed level of PLD itself may be, at least in part, responsible for the increase in GTPgammaS-dependent PLD activity during granulocytic differentiation of HL60 cells.

Comparative mapping of QTLs for agronomic traits of rice across environments using a doubled haploid population

We report here the RFLP mapping of quantitative triat loci (QTLs) that affect some important agronomic traits in cultivated rice. An anther culturederived doubled haploid (DH) population was established from a cross between an indica and a japonica rice variety. On the basis of this population a molecular linkage map comprising 137 markers was constructed that covered the rice genome at intervals of 14.8cM on average. Interval mapping of the linkage map was used to locate QTLs for such important agronomic traits as heading date, plant height, number of spikelets per panicle, number of grains Per panicle, 1000-grain weight and percentage of seed set. Evidence of genotype-byenvironment interaction was found by comparing QTL maps of the same population grown in three diverse environments. A total of 22 QTLs for six agronomic traits were detected that were significant in at least one environment, but only 7 were significant in all three environments, 7 were significant in two environments and 8 could only be detected in a single environment. However, QTL-by-environment interaction was traitdependent. QTLs for spikelets and grains per panicle were common across environments, while traits like heading date and plant height were more sensitive to environment.

Activation of mitogen-activated protein (MAP) kinase pathway by pervanadate, a potent inhibitor of tyrosine phosphatases

Rapid tyrosine phosphorylation of key cellular proteins is a crucial event in signal transduction. The regulatory role of protein-tyrosine phosphatases (PTPs) in this process was explored by studying the effects of a powerful PTP inhibitor, pervanadate, on the activation of the mitogen-activated protein (MAP) kinase cascade. Treatment of HeLa cells with pervanadate resulted in a marked inhibition of PTP activity, accompanied by a drastic increase in tyrosine phosphorylation of cellular proteins. The increased tyrosine phosphorylation coincided with the activation of the MAP kinase cascade as indicated by enzymatic activity assays of MEK (MAP kinase/ERK-kinase) and MAP kinase and gel mobility shift analyses of Raf-1 and MAP kinase. The activation was sustained but reversible. Upon removal of pervanadate, both tyrosine phosphorylation and MAP kinase activation declined to basal levels. Therefore, inhibition of PTP activity is sufficient per se to initiate a complete MAP kinase activation program.

Localization of a high-affinity inositol 1,4,5-trisphosphate/inositol 1,4,5,6-tetrakisphosphate binding domain to the pleckstrin homology module of a new 130 kDa protein: characterization of the determinants of structural specificity

We have previously identified a novel 130 kDa protein (p130) which binds Ins(1,4,5)P3 and shares 38% sequence identity with phospholipase C-delta 1 [Kanematsu, Misumi, Watanabe, Ozaki, Koga, Iwanaga, Ikehara and Hirata (1996) Biochem. J. 313, 319-325]. We have now transfected COS-1 cells with genes encoding the entire length of the molecule or one of several truncated mutants, in order to locate the region for binding of Ins(1,4,5)P3. Deletion of N-terminal residues 116-232, the region which corresponds to the pleckstrin homology (PH) domain of the molecule, completely abolished binding activity. This result was confirmed when the PH domain itself (residues 95-232), isolated from a bacterial expression system, was found to bind [3H]Ins(1,4,5)P3. We also found that Ins(1,4,5,6)P4 was as efficacious as Ins(1,4,5)P3 in displacing [3H]Ins(1,4,5)P3, suggesting that these two polyphosphates bind to p130 with similar affinity. This conclusion was confirmed by direct binding studies using [3H]Ins(1,4,5,6)P4 with high specific radioactivity which we prepared ourselves. Binding specificity was also examined with a variety of inositol phosphate derivatives. As is the case with other PH domains characterized to date, we found that the 4,5-vicinal phosphate pair was an essential determinant of ligand specificity. However, the PH domain of p130 exhibited some novel features. For example, the 3- and/or 6-phosphates could also contribute to overall binding; this contrasts with some other PH domains where these phosphate groups decrease ligand affinity by imposing a steric constraint. Secondly, a free monoester 1-phosphate substantially increased binding affinity, which is a situation so far unique to the PH domain of p130.

Ribotyping to differentiate Fusobacterium necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme isolated from bovine ruminal contents and liver abscesses

Differences in biological activities (hemagglutination, hemolytic, leukotoxic, and virulence) and ribotypes between the two subspecies of Fusobacterium necrophorum of bovine ruminal and liver abscess origins were investigated. Hemagglutination activity was present in all hepatic, but only some ruminal, strains of Fusobacterium necrophorum subsp. necrophorum. Ruminal F. necrophorum subsp. necrophorum had low leukotoxin titers yet was virulent in mice. Fusobacterium necrophorum subsp. funduliforme of hepatic or ruminal origin had no hemagglutination activity, had low hemolytic and leukotoxic activities, and was less virulent to mice. For ribotyping, chromosomal DNAs of 10 F. necrophorum subsp. necrophorum and 11 F. necrophorum subsp. funduliforme isolates were digested with restriction endonucleases (EcoRI, EcoRV, SalI, PstI, and HaeIII) and examined by restriction fragment length polymorphisms after hybridizing with a digoxigenin-labeled cDNA probe transcribed from a mixture of 16 and 23S rRNAs from Escherichia coli. The most discriminating restriction endonuclease enzyme for ribotyping was EcoRI. The presence or absence of two distinct bands of 2.6 and 4.3 kb differentiated the two subspecies. Regardless of the origin, only F. necrophorum subsp. necrophorum, a virulent subspecies, had a ca. 2.6-kb band, whereas F. necrophorum subsp. funduliforme, a less virulent subspecies, had a ca. 4.3-kb band. Ribotyping appears to be a useful technique to genetically differentiate the two subspecies of F. necrophorum.

Altered expression of protein-tyrosine phosphatase 2C in 293 cells affects protein tyrosine phosphorylation and mitogen-activated protein kinase activation

PTP2C, an SH2 domain-containing protein-tyrosine phosphatase, is recruited to the growth factor receptors upon stimulation of cells. To investigate its role in growth factor signaling, we have overexpressed by approximately 6-fold the native PTP2C and a catalytically inactive mutant of the enzyme in 293 human embryonic kidney cells. The native PTP2C was located entirely in the cytosol, while the inactive mutant was nearly equally distributed in cytsolic and membrane fractions. Expression of the latter caused hyperphosphorylation on tyrosine of a 43-kDa protein, which was coimmunoprecipitated and co-partitioned in the plasma membrane fraction with the inactive PTP2C mutant. This protein may represent a physiological substrate of PTP2C. Overexpression of the native PTP2C enhanced epidermal growth factor (EGF)-stimulated mitogen-activated protein (MAP) kinase activity by 30%, whereas expression of the inactive mutant reduced the stimulated activity by 50%. Similar effects were observed for the activation of MAP kinase as determined by activity assay, gel mobility shift, and tyrosine phosphorylation. The data suggest that the phosphatase activity of PTP2C is partly required for MAP kinase activation by EGF and that PTP2C may function by dephosphorylating the 43-kDa membrane protein.

[Osteoclastic resorption of Haversian system of femoral neck cortex in aged women]

Osteoclastic resorption was studied with scanning electron microscope on cross sections of cortical bone of femoral neck collected from 7 aged women with an average age of 72.4 years, who underwent endoprosthetic replacement for intracapsular hip fracture. The cortical bone sections revealed enlargement of the Haversian canals. On the inner linings of the enlarged canals there were many oval-shaped resorption lacunae, reflecting osteoclastic resorption of the Haversian systems. The osteoclastic resorption with subsequent enlargement of the Haversian canals into round or oval cavities took place first over the inner portions of the cortical sections, thereby rendering these areas porotic (cancellization). These processes of the Haversian system and canals then gradually emerged over the central and eventually over the outer areas of the cortical bone, and the entire cortical bone became porotic. In the meanwhile, the inner porotic portion of the cortex turned into trabeculae (trabecularization) and became gradually resorbed, resulting in thinning of the medial cortex. Cortical cancellization, trabecularization and thinning so compromised the material strength of the femoral neck that fracture would ensue even with trivial injury.

The effects of mastoparan on the carrot cell plasma membrane polyphosphoinositide phospholipase C

When [3H]inositol-labeled carrot (Daucus carota L.) cells were treated with 10 or 25 microM wasp venom peptide mastoparan or the active analog Mas-7 there was a rapid loss of more than 70% of [3H]phosphatidylinositol-4-monophosphate (PIP) and [3H]phosphatidylinositol-4,5-bisphosphate (PIP2) and a 3- and 4-fold increase in [3H]inositol-1,4-P2 and [3H]inositol-1,4,5-P3, respectively. The identity of [3H]inositol-1,4,5-P3 was confirmed by phosphorylation with inositol-1,4,5-P3 3-kinase and co-migration with inositol-1,3,4,5-P4. The changes in phosphoinositides were evident within 1 min. The loss of [3H]PIP was evident only when cells were treated with the higher concentrations (10 and 25 microM) of mastoparan or Mas-7. At 1 microM Mas-7, [3H]PIP increased. The inactive mastoparan analog Mas-17 had little or no effect on [3H]PIP or [3H]PIP2 hydrolysis in vivo. Neomycin (100 microM) inhibited the uptake of Mas-7 and thereby inhibited the Mas-7-stimulated hydrolysis of [3H]PIP and [3H]PIP2. Plasma membranes isolated from mastoparan-treated cells had increased PIP-phospholipase C (PLC) activity. However, when Mas-7 was added to isolated plasma membranes from control cells, it had no effect on PIP-PLC activity at low concentrations and inhibited PIP-PLC at concentrations greater than 10 microM. In addition, guanosine-5'-O-(3-thiotriphosphate) had no effect on the PIP-PLC activity when added to plasma membranes isolated from either the Mas-7-treated or control cells. The fact that Mas-7 did not stimulate PIP-PLC activity in vitro indicated that the Mas-7-induced increase in PIP-PLC in vivo required a factor that was lost from the membrane during isolation.

Application of the external perichondrium of the ala of the thyroid cartilage of the nondiseased side in laryngeal surgery

Since 1976, in our department, the external perichondrium of the ala of the thyroid cartilage of the nondiseased side has been successfully applied in repairing endolaryngeal defects and reconstructing the laryngeal wall in 22 cases. The postoperative result was good in the most cases.

DNA damage and the proliferation and aging of cells in culture: a mathematical model with time lag

This paper is an extension of an earlier one by the same author in which a mathematical model was presented to describe the proliferation and aging of cells in culture. The model consists of a group of ordinary differential equations with a time lag. In the previous paper, the time lag was omitted for simplicity and the resulting differential equations were resolved analytically. It was shown that the model explains the behavior of a cell culture reasonably well. In this paper, the analytical solution of the original differential equations is presented without omitting the time lag. An analytical description of the variations in doubling capability between sister cells that was only simulated numerically in the earlier paper is given.

[Quality control of xiaoqinglong mixture]

TLC was used to detect ephedrine, paeoniflorin, glycyrrhizic acid, cinnamic aldehyde and xixin volatile oils in Xiaoqinglong mixture. Paeoniflorin was determined by HPLC. The average recovery is 99.42%, and RSD 0.23%.

[Effects of air pollution on health of residents in vicinity of an electrometallurgical factory in Chengdu]

Air pollution in an electrometallurgical plant in Chengdu was monitored in 1988. Results showed that atmospheric TSP and Ni concentrations in the vicinity of the plant were higher than those in control area; and TSP content higher than its health standard level. A population of 262 children was physically examined in the same pollution and control areas in May, 1988. Physical examinations were as follows:otorhinolaryngological examination, skin patch test of Ni and Co, immune function test (including PHA skin test, salivary LZM content), Ni levels in human hair and urine etc. We found that body burdens of Ni in population of pollution area increased because of the pollution of Ni compounds in the atmosphere. Hair Ni content in pollution area was significantly higher than that in control area, and the positive rate of Ni skin patch test was also markedly higher than that in control area. Case history indicated that there was a significant difference in Ni content as detected by otorhinolaryngological examinations between the pollution and control areas. Some measures were suggested to improve the air quality based on the study.

Association of Phosphatidylinositol Kinase, Phosphatidylinositol Monophosphate Kinase, and Diacylglycerol Kinase with the Cytoskeleton and F-Actin Fractions of Carrot (Daucus carota L.) Cells Grown in Suspension Culture : Response to Cell Wall-Degrading Enzymes

Phosphatidylinositol kinase (PI), phosphatidylinositol monophosphate (PIP) kinase, and diacylglycerol (DAG) kinase activities were detected in the cytoskeletal fraction isolated from microsomes and plasma membranes of carrot (Daucus carota L.) cells grown in suspension culture. The lipid kinase activities were associated with the actin filament fraction (F-actin fraction) isolated from the cytoskeleton. The PI and PIP kinase activity in the F-actin fraction significantly increased after cells were treated with Driselase, a mixture of cell wall-degrading enzymes; however, the DAG kinase activity in the F-actin fraction was unaffected by the Driselase treatment. These data indicate that at least one form of PI, PIP, and DAG kinase preferentially associates with actin filaments and/or actin binding proteins and that cytoskeletal-associated PI and PIP kinase activities can change in response to external stimulation.

Oxygen-dependent reperfusion injury in the isolated rat lung

To further define the relationship between oxygen dependence of lung injury during ischemia and ischemia-reperfusion, we used the isolated, perfused, and ventilated rat lung model, so that oxygenation and perfusion could be separated. During ischemia, lungs were ventilated with various oxygen concentrations and then ventilated with 95% oxygen during the 60-min reperfusion period. Other lungs were ventilated with 0% oxygen (nitrogen) during ischemia, and the reperfusion phase oxygen concentration was varied. Tissue and perfusate lipid peroxidation products (thiobarbituric acid-reactive substances and conjugated dienes), dry-to-wet weight ratio, and lactate dehydrogenase were measured as indexes of lung damage. In addition, electron microscopy of some lungs was performed. Results demonstrate an oxygen dependence of lipid peroxidation in both the ischemic and reperfusion phases, but lipid peroxidation is severalfold greater in the reperfusion than in the ischemic phase. Products of lipid peroxidation closely correlate with indexes of lung injury (dry-to-wet weight ratio, lactate dehydrogenase, and electron microscopy).

Electrolyte induced vesiculation of MA782 mice mammary adenocarcinoma ascites cells

MA782 ascites cells were found to vesiculate when incubated in electrolyte solutions and release giant plasma membrane vesicles with diameters ranging from 5 microns to 15 microns. The vesicles, generated from the plasma membrane and free of cellular organelles, as visualized by microscopy and marker-enzyme analysis, could be proposed as a useful model membrane system.

Solution conformation of d-CTCGAGCTCGAG by two-dimensional NMR: conformational heterogeneity at XhoI cleavage site

Nonexchangeable proton resonances in the 500-MHz NMR spectrum of d-CTCGAGCTCGAG have been assigned by using two-dimensional correlated spectroscopy (COSY) and nuclear Overhauser enhancement spectroscopy (NOESY). 1H-1H coupling constants (J) in the deoxyribose rings have been measured by analyzing intensity and multiplet patterns in the phase-sensitive omega 1-scaled COSY spectra. A modification of the J-resolved technique, called amplitude-modulated J-resolved spectroscopy, has been described and used to increase the accuracy of J measurements. Absorption mode omega 1-scaled NOESY spectra at mixing times in the range 50-200 ms have been analyzed to monitor spin diffusion. A 50-ms spectrum has been used to estimate several interproton distances. The coupling constant and distance data have been used to arrive at sequence-specific sugar geometries and glycosidic torsion angles. The backbone structure has been refined by model building using the FRODO program, employing the sugar geometries and glycosidic torsion angles discussed above. The molecule shows interesting sequence-dependent variations in the structure. The cleavage site of the restriction enzyme XhoI exhibits unique differences in the sugar geometry and backbone torsion angles.