Biomedical subjects

W Ma

Publications and source records attributed to W Ma.

At least 163 records · Page 9Linked to original sources

PubMed1999

Increase of galanin mRNA in lumbar dorsal root ganglion neurons of adult rats after partial sciatic nerve ligation.

Partial sciatic nerve ligation (PSNL) is a widely used model for the study of neuropathic pain. However, there is little information on neuropeptide expression in primary sensory neurons after PSNL. We examined galanin (GAL) mRNA expression in L4 and L5 dorsal root ganglion (DRG) neurons of adult rats after PSNL. We found that 4 and 14 days after PSNL the percentages of GAL mRNA positive neurons were significantly increased in the ipsilateral DRG compared to the contralateral side. Using combined retrograde fluorescent dye tracing and in situ hybridization, we found that 47% of the injured neurons and 10% of the spared neurons were GAL mRNA positive. Since only 2-3% of neurons in the contralateral uninjured DRG were GAL mRNA positive, PSNL induced up-regulation of GAL mRNA in both injured and spared DRG neurons.

Animals↗

PubMed1999

N-linked oligosaccharides of vomeromodulin, a putative pheromone transporter in rat.

Vomeromodulin, a putative pheromone transporter of the rat vomeronasal organ, was isolated by lectin chromatography, purified, and subjected to a mass spectrometric (MS) system of glycan structural determination. Through a combination of exoglycosidase treatments and measurements by matrix-assisted laser desorption/ionization MS, the N-glycans of vomeromodulin were identified as mainly sialylated and fucosylated biantennary structures. The microheterogeneity of N-glycan structures was also due to the presence of galactose residues with different types of linkages.

Animals↗

PubMed1999

Spatial and temporal distribution of cellular proliferation in the cranial base of normal and midfacially retrusive mice.

The craniofacial region of the Brachyrrhine (Br) mouse is characterized by a retruded midface. The cellular mechanism causing this growth deficiency is unknown. However, the cranial base is foreshortened in adult Br mice. The purpose of this study was to determine whether the spatial and temporal patterns of cellular proliferation in the cranial base (CB) differ between normal (C3H/HeJ) and Br mutant (3H1 Br/+) embryonic mice. Twenty-four dams were injected (3)H thymidine (5 microCi/gram body weight) and 15 embryos from each group were collected at Theiler stages 23, 25, and 27 (15, 17, and 19 days of gestation). Serial sections from each head were processed with routine autoradiography. Labelling indices (LI) were determined for each specimen and cellular proliferation maps were generated for each age group. LI patterns within and between groups were compared statistically. Results showed that cellular proliferation in the CB of normal embryos displayed a time- and position-dependent pattern, characteristic of transient growth sites (TGS). Generally, as age increases, cellular proliferative activities decrease gradually (from an average LI of 11.4 +/- 5.7% at stage 23 to 4.4 +/- 2.2% at stage 27), and the number of the TGS decreases in the presumptive nasal septal region and increases in presumptive sphenoethmoidal area with age, indicating the existence of cellular subpopulations in the CB. Cellular proliferation in the CB of the Br mutant displays a different growth pattern compared to the normal condition. Deficiencies in cellular proliferation exist mainly in the presumptive sphenoethmoidal area of the CB. The results indicate that the TGS play an important role in the normal morphogenesis of the CB, and abnormalities in their timing and/or position may be responsible for the dysmorphology of the midface in the Br mutant.

Animals↗

PubMed1999

Increased calcitonin gene-related peptide immunoreactivity in gracile nucleus after partial sciatic nerve injury: age-dependent and originating from spared sensory neurons.

Following a unilateral chronic constriction injury of the sciatic nerve, calcitonin gene-related peptide (CGRP)-immunoreactive (IR) fiber density increases in the ipsilateral gracile nucleus, and this is more pronounced in aged (16-month) rats where the fibers are dystrophic. In this study we show that a second type of partial sciatic nerve injury, a half-transection, also induces CGRP-IR fibers in the gracile nucleus, but this effect is strongly age-dependent, being much more pronounced in 8- to 10-month-old rats than in 2- to 3-month-old rats. Dystrophic CGRP-IR fibers were rarely observed in 8- to 10-month-old animals, so the increased reaction in aged animals and axonal dystrophy are separate phenomena. Using double-labeling with fluorescent dye tracing for 8- to 10-month-old rats, we showed that neuron profiles in the dorsal root ganglion (DRG) with peripheral axons spared by the partial sciatic nerve injury were 10 times more likely to be CGRP mRNA-positive than profiles with injured peripheral axons, suggesting that spared neurons are more likely to contribute to the increase in CGRP-IR fibers in the gracile nucleus. Using combined fluorescent dye tracing with in situ hybridization for CGRP mRNA or CGRP immunostaining, we further showed that CGRP-expressing DRG neuron profiles with central projections to the gracile nucleus had peripheral axons spared by the partial nerve injury. We conclude that the increased CGRP immunoreactivity in the gracile nucleus following partial sciatic nerve injury originates from primary sensory neurons with axons spared by the injury. These neurons may still transmit cutaneous sensory information and thus the increased CGRP immunoreactive fibers in the gracile nucleus may be involved in the mechanical allodynia characteristic of neuropathic pain syndromes following partial nerve injury.

Aging↗

PubMed1999

Ultrastructural localization of increased neuropeptide immunoreactivity in the axons and cells of the gracile nucleus following chronic constriction injury of the sciatic nerve.

Neuropeptide plasticity in the gracile nucleus is thought to play a role in the development of neuropathic pain following nerve injury. Two weeks after chronic constriction injury of adult rat sciatic nerve, galanin, neuropeptide Y and calcitonin gene-related peptide immunoreactivities were increased in fibers and cells in the gracile nucleus ipsilateral to injury. At the electron microscopic level, this increased neuropeptide immunoreactivity was localized in myelinated axons, boutons, dendrites, neurons and glial cells. Galanin-, neuropeptide Y- and calcitonin gene-related peptide-immunoreactive boutons were frequently presynaptic to dendrites of both immunoreactive and non-immunoreactive neurons. However, no neuropeptide Y, galanin and calcitonin gene-related peptide messenger RNA was detected in the injured side gracile nuclei by in situ hybridization. These results show that partial nerve injury to the sciatic nerve induces increases in the content of galanin, neuropeptide Y and calcitonin gene-related peptide immunoreactivities in synaptic terminals within the gracile nucleus, which suggests that there may be increased release of these neuropeptides following sensory or spontaneous stimulation of large-diameter primary afferents following partial nerve injury, perhaps one mechanism involved in neuropathic pain. We also show an apparent transfer of these neuropeptides to the cells of the gracile nucleus, both neurons and glial cells, an intriguing phenomenon of unknown functional significance.

Animals↗

PubMed1999

Sex differences in expression of serotonin receptors (subtypes 1A and 2A) in rat brain: a possible role of testosterone.

Sexual differences in the expression of messenger RNA and in the binding of serotonin receptors (subtypes 1A and 2A) were studied by in situ hybridization and autoradiography ¿[3H]8-hydroxy-2(di-n-propylamino)tetralin and [3H]ketanserin binding) in the rat brain. Serotonin-1A receptor messenger RNA showed distinct expression patterns for female and male rats. Expression of serotonin-1A receptor messenger RNA was greater in males in subregions of the hypothalamus and amygdala, and less in males in subregions of the hippocampus. No significant differences in the distribution of serotonin-1A receptor binding sites were found between the sexes. Serotonin-2A receptor messenger RNA expression was comparable in males and females in all brain regions except the ventromedial hypothalamic nuclei, where lower levels were seen in females. However, the binding of serotonin-2A receptor measured with [3H]ketanserin was significantly higher in females in all regions of the hippocampus. In a separate study, gonadectomy in males significantly increased serotonin-1A messenger RNA content in the cortex, hypothalamus, hippocampus, amygdala and dorsal raphe, and decreased serotonin-2A messenger RNA in ventromedial hypothalamic nuclei only. Almost all gonadectomy-induced changes were reversed by concomitant administration of testosterone. Our data provide evidence for region-specific sex differences in serotonin receptor subtype 1A and 2A transcription and concentration in the rat brain, and further suggest a modulatory role of testosterone in serotonin (particularly subtype 1A) receptor expression. Gender and gonadal steroid effects on central serotonergic systems may underlie the reported sexual dimorphisms in affective state regulation, response to psychopharmacological agonists or pituitary adrenal activation.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1999

Induction of apoptosis and inhibition of human gastric cancer MGC-803 cell growth by arsenic trioxide.

Arsenic trioxide (As2O3), used to treat human diseases for centuries in traditional Chinese medicine, has been identified as a very effective antileukaemic agent, but its effect on solid tumours which could be more suitable for clinical treatment with arsenic compounds is still unknown. In this study, we investigated the in vitro effect of As2O3 at concentrations of 0.01-1 microM against six human malignant cell lines, MGC-803, HIC, MCF-7, HeLa, BEL-7402 and A549 cells. As2O3 inhibited growth and induced apoptosis in these malignant cells at varying degrees, in a time dose-dependent manner. The most marked effects were seen in the gastric cancer cell line, MGC-803. In contrast, minimal growth inhibition and induction of apoptosis occurred in human embryonic pulmonary cells following treatment with As2O3 found at the same concentrations. Changes in intracellular Ca2+, following As2O3 treatment were measured by Ca2+ sensitive fluorescent probe Indo-1/AM in flow cytometric assays. The increase in intracellular Ca2+ correlated with the sensitivity of these cells to As2O3, possibly indicating that a critical intracellular Ca2+ signal transduction pathway could be involved in As2O3-mediated cell-death and its selectivity. The marked sensitivity of MGC-803 cells in vitro suggests that As2O3 may be a potential antigastric cancer agent.

Antineoplastic Agents↗

PubMed1999

A unique urinary constituent, 6-hydroxy-6-methyl-3-heptanone, is a pheromone that accelerates puberty in female mice.

BACKGROUND: Olfactorily mediated puberty acceleration in female mice (measured by an increase in uterine weight) has been observed since the 1960s without the active chemosignal being structurally identified. There are many controversies in the literature as to whether this male-originated pheromone is a volatile substance. We investigated the chemical nature of the urinary fractions that are responsible for the characteristic uterine weight increases. RESULTS: The active pheromone was identified as 5,5-dimethyl-2-ethyltetrahydrofuran-2-ol and/or its open-chain tautomer (6-hydroxy-6-methyl-3-heptanone). A series of cyclic vinyl ethers were isolated from chromatographically active fractions of the urine. Because these compounds did not accelerate puberty, we postulated that these ethers were degradation products of a lactol (5,5-dimethyl-2-ethyltetrahydrofuran-2-ol). The lactol was then detected directly in the mouse urine extract using a silylation agent. Synthetic 6-hydroxy-6-methyl-3-heptanone had strong biological activity, whereas its close structural analogs did not. CONCLUSIONS: The male house mouse excretes into its urine a large quantity of a volatile substance that has a unique lactol/hydroxyketone structure. This substance is capable of binding to the less volatile urinary constituents, such as proteins or peptides, and is active in puberty-acceleration bioassays. The controversies regarding the volatility of the puberty-accelerating pheromones can now be explained by considering a complex of volatile lactol/hydroxyketone and urinary proteins.

Animals↗

PubMed1999

The role of hydroxyl radical as a messenger in the activation of nuclear transcription factor NF-kappaB.

Although it is generally believed that reactive oxygen species activate NF-kappaB, a primary oxidative stress-responsive transcription factor, it is unclear which one among these species causes NF-kappaB activation. Our hypothesis is that hydroxyl radical (*OH) functions as a messenger for the activation of NF-kappaB. Jurkat cells, macrophages and JB6 cells were used to test this hypothesis. Cr(VI), silica and ZnO were used as sources of *OH radicals. None of these *OH generating systems involves exogenous H2O2. Cr(VI) expressed enhanced activity in induction of NF-kappaB in Jurkat cells. This activation of NF-kappaB was decreased by a metal chelator, diethylene triaminepentaacetic acid or a H2O2 scavenger, catalase, but was increased by superoxide dismutase. Mn(II), which reacts with Cr(IV) to inhibit this metal ion-mediated *OH generation, decreased the NF-kappaB activation. Sodium formate, an *OH radical scavenger, also inhibited the NF-kappaB activation. Electron spin resonance measurements show that Cr(VI) was reduced by Jurket cells to Cr(IV) and Cr(V). During the reduction process, molecular oxygen was reduced to O2 and then to H2O2, which reacted with Cr(IV) and Cr(V) to generate *OH radical. The *OH generation correlated with the Cr(VI)-induced NF-kappaB activation. Similarly, silica caused NF-kappaB activation in macrophages via the *OH radical-mediated reaction. This radical was generated via metal mediated reaction from H2O2, which was generated by the reduction of molecular oxygen via O2- as an intermediate during the silica-stimulated 'respirable burst'. Silica particles did not cause *OH generation either in Jurket or in JB6 cells and thus did not cause any observable NF-kappaB activation in these cells. ZnO induced NF-kappaB activation in JB6 cells through the generation of *OH resulting from light irradiation of ZnO which was measured by electron spin resonance. The results thus show that *OH radical functions as a messenger for NF-kappaB activation. Antioxidants, which scavenge *OH radical or its precursors, inhibit NF-kappaB activation. Metal chelators, which make metal ions incapable of generating *OH from H2O2, inhibit activation of this transcription factor.

Animals↗

PubMed1999

Induction of estrus in grouped female mice (Mus domesticus) by synthetic analogues of preputial gland constituents.

Two major volatile constituents of the male mouse preputial gland, E,E-alpha-farnesene and E-beta-farnesene, were examined for their role in inducing estrous cycles in grouped female mice. The results indicated that the mixture of the farnesenes was as effective as the homogenate of the intact preputial gland, while the extract of the castrate preputial tissue did not show a pronounced response.

Animals↗

PubMed1999

Association of obesity with hiatal hernia and esophagitis.

OBJECTIVE: Although weight loss is commonly recommended for symptoms of gastroesophageal reflux, a relationship between excessive body weight and esophageal reflux has not been established. The aim of this study was to determine whether obesity is associated with the presence of a hiatal hernia (HH) and/or an endoscopic diagnosis of esophagitis. METHODS: Retrospective case control studies were done using 1389 patients who underwent gastric analysis and upper GI endoscopy between 1974 and 1995. After excluding patients with Zollinger-Ellison syndrome, 189 cases of esophagitis with 1024 controls were identified. In a separate analysis of the database, 151 cases of HH with 1053 controls were also identified. Patients were classified by body mass index (BMI) as: thin (BMI <20 kg/m2), normal (BMI 20-25), mildly obese (BMI 25-30), and obese (BMI >30). RESULTS: Excessive body weight was significantly associated with the presence of HH, the probability of HH increasing with each level of BMI (p < 0.01), as well as with esophagitis (OR 1.8; 95% CI 1.4-2.1). HH was independently associated with esophagitis (OR 4.2 95% CI 2.9-6.1); when controlled for the effect of HH, the association between BMI and esophagitis diminished but remained significant. In the population as a whole, for the presence of esophagitis multiple logistic regression indicates BMI and hiatal hernia were significant factors but gender and race did not appear to be. CONCLUSIONS: Excessive body weight is a significant independent risk factor for hiatal hernia and is significantly associated with esophagitis, largely through an increased incidence of hiatal hernia. Whites are more likely to have the combination of esophagitis and hiatal hernia than are blacks.

Body Mass Index↗

PubMed1999

Efficiency of leukocyte removal by filters made of superfine glass fiber membranes.

BACKGROUND AND OBJECTIVES: To demonstrate the application of leukocyte removal filters made of a new type of filter material - superfine glass fiber - for depleting leukocytes in SAGM red cell suspensions and preventing nonhemolytic transfusion reactions. MATERIALS AND METHODS: The extent of leukocyte depletion and red cell recovery was based on cell counts. Trace leukocytes were counted in a 50-microl Nageotte counting chamber or by using a flow cytometer. The chemical stability of the glass fiber membranes was studied by plasma emission spectrometer and by measuring the ion content and weighing nonvolatile matter in water extract. The structural stability of the glass fiber membranes was studied by a micropore-filter membrane method. RESULTS: Leukocyte removal filters made of superfine glass fiber membranes removed more than 99.0% of leukocytes in SAGM red cell suspensions prepared from 400 ml whole blood. Red cell recovery exceeded 90%, and the total number of residual leukocytes was less than 5x10(6). A water extract of the glass fiber membranes contained only traces of Si4+ and Ca2+ and less than 2 mg/100 ml of nonvolatile matter. No broken or loose fibers were found in the filters. Scanning electron microscopy showed that the web structure of the glass fiber membranes was instrumental in trapping and holding leukocytes. CONCLUSION: A filter made of glass fiber membranes is effective in leukocyte depletion.

Adenine↗

PubMed1999

A full color system for quantitative assessment of histochemical and immunohistochemical staining patterns.

Quantitative measures of staining distributions are important to compare the presence and patterns of cells or macromolecules. Typically, achromatic thresholding systems are used to compare staining distributions. Achromatic video signals, however, lack sufficient resolution to identify and compare chromatic changes. The purpose of this study is to describe a full color system for analysis of chromatic staining distributions. The hardware system includes a Leitz Diaplan microscope, video camera, GVP videoboard and Amiga 3000 computer. Software was developed in "C" to partition the video signal into hue (H), saturation (S) and value (V). Also, percentage of stained area was determined. Kodak color filters were used to assess the accuracy and precision of the system. Craniofacial tissues were stained with varying concentrations of toluidine blue and primary anti-BrdU antibodies. HSV and the percentage of stained areas were determined and displayed low coefficients of error. HSV values also performed as expected for standard filters as well as cellular staining concentrations. This system is easily implemented and should be useful for comparing chromatic changes with any color resulting from histochemical or immunohistochemical procedures.

Image Processing, Computer-Assisted↗

PubMed1999

A role for inwardly rectifying K+ channels in differentiation of NG108-15 neuroblastoma x glioma cells.

The whole-cell patch-clamp technique was used to assess the current carried by inwardly rectifying K+ channels (K(ir)) and the resting membrane potential (RMP) during long-term culture of NG108-15 cells. Culture of this cell line in serum-free medium triggers differentiation of a type I, neuron-like cell type followed by an eventual predominance of a type II, proliferative cell type. NG108-15 K(ir) currents, which strongly resemble currents carried by human ether-a-go-go related gene (HERG) K+ channels, exhibited significantly smaller current density for the more depolarized undifferentiated cells in growth media (GM) and type II cells compared to the neuron-like type I cells. Detailed examination of the transition from undifferentiated GM cells to type I cells revealed a shift in the voltage dependence of K(ir) activation which paralleled the more hyperpolarized RMP, neurite outgrowth, and biochemical differentiation characteristic of type I cells. Reverse-transcription polymerase chain reaction experiments using primers for the rat variant of HERG, RERG, revealed a a nearly twofold increase in RERG mRNA as cells differentiate from GM to type I, a finding entirely consistent with the increased K(ir) current density derived from patch-clamp recordings. Administration of CsCl(5 mM) blocked K(ir) currents and depolarized the RMP of type I cells. Furthermore, culture of NG108-15 cells in serum-free medium but with CsCl added significantly prevented neurite extension, an effect which was entirely reversible upon subsequent removal of CsCl. In contrast, other K+ channel inhibitors (4-aminopyridine and tetraethylammonium), at concentrations without marked effects on K(ir), failed to affect neurite extension. These results suggest an important role of the K(ir) channels in determining the RMP and triggering morphological differentiation of the cell line.

Animals↗

PubMed1999

Inhibition of spontaneous GABAergic transmission by trimethylolpropane phosphate.

Trimethylolpropane phosphate (TMPP) is a neuroactive organophosphate generated during partial pyrolysis of a synthetic ester turbine engine lubricant. While TMPP had been shown to have little affinity for acetylcholinesterase, previous binding studies and 6Cl- flux measurements have implicated TMPP as an antagonist of GABA, receptor/Cl- channels. Using the whole-cell patch clamp method, spontaneous inhibitory postsynaptic currents (sIPSCs) mediated by bicuculline-sensitive GABA(A) receptors were measured in neurons cultured from the rat embryonic hippocampus for 13-21 days. Experiments were conducted in the presence of tetrodotoxin and 6-cyano-7-nitroquinoxaline to inhibit spontaneous presynaptic action potentials and glutamate transmission, respectively, thus isolating GABAergic sIPSCs for study. TMPP induced a concentration-dependent inhibition of sIPSC amplitude and frequency suggesting both postsynaptic and presynaptic actions. Administration of 5 microM TMPP reversibly diminished sIPSC amplitude by 23 +/- 8% (mean SEM, n=5 cells) while markedly decreasing the mean sIPSC frequency by 40 +/- 2% (n=5). The mean time constant of sIPSC decay was reversibly decreased by 20 +/- 4% (n=3) in the presence of 20 microM TMPP, suggesting an increase in the rate of inactivation. To directly verify the blockade of ionotropic GABA receptors by TMPP, the effects of TMPP were examined on whole-cell Cl- current responses activated by exogenous GABA. Administration of TMPP (5 microM) depressed peak whole-cell GABA-induced currents to 73 1% (n=4) of control levels, consistent with the results on sIPSC amplitude. Our data directly demonstrate that TMPP directly inhibits GABA(A) receptor function, as indicated by the blockade of whole-cell GABA-mediated Cl- current and the reduction in sIPSC amplitude. Furthermore, TMPP exerts a presynaptic effect on GABAergic transmission, as evidenced by the reduction in sIPSC frequency, which may be independent of a GABA(A) receptor. The molecular basis for the presynaptic action of TMPP remains to be elucidated.

Animals↗

PubMed1999

[A quantitative histological investigation of salivary glands of human and experimental animals].

The pairs of three major salivary glands of eight kinds of full grown experimental animals were sectioned and examined by morphometric techniques. The televised image-analysis system was used to determine the acinar area and proportional volumes of component tissue. The results were compared with those of the same glands from human. There were no differences between the three acinar areas of human and monkey. The acinar area of human parotid was the smallest except that of rabbit. The acinar area of human submandibular gland was larger than that of rodents but smaller than that of other animals. There were no differences between the acinar area of sublingual glands of human and animal except those of rabbit and goat. The acinar area of mucous acini was larger than that of serous and seromucous acini. The mean proportional volume of acini of human parotid was less than that of other animals. The duct systems of rodents submandibular were far more than those of other animals. In sublingual glands, there were no differences in mean proportional volume of component tissue between human and animals except there were more acini and less fiber in rodents' subingual glands.

Animals↗

PubMed1999

Changes in serum cardiac troponin I levels after percutaneous transluminal coronary angioplasty.

OBJECTIVE: To evaluate the possible effect of percutaneous transluminal coronary (PTCA) on myocardium. METHODS: Serum cTnl and CK-MB were measured in 60 patients with coronary artery disease (CAD) who underwent PTCA before and at the 6th, 12th, 24th, 48th and 72nd hour after the interventional procedure respectively. RESULTS: The serum cTnl levels began to increase at 6 hours (9.65 +/- 6.27 micrograms/L) in 18 patients, reached the peak levels during 12-24 hours (20.43 +/- 11.28 micrograms/L, 18.52 +/- 9.52 micrograms/L), and returned to normal range till 48-72 hours (7.35 +/- 7.62 micrograms/L, 5.51 +/- 3.13 micrograms/L) after PTCA. The serum cTnl and CK-MB levels were kept normal range pre- and post-PTCA in 30 cases. The levels of cTnl in 12 cases were over baseline either before or after the procedure, while for CK-MB, only in 3 cases were over normal range after PTCA. Compared with normal cTnl group, elevated cTnl levels were related to total inflation times and dilated times (P < 0.05). CONCLUSIONS: PTCA may cause some minor damage in myocardium, serum cTnl level was more sensitive and specific for monitoring myocardial injury.

Adult↗

PubMed1999

[Cloning and sequencing of variable region gene of heavy chain of monoclonal antibody against SA I/II of Streptococcus mutans].

OBJECTIVE: To clone and sequence a immunoglobulin variable region of heavy chain (VH) from a mouse hybridoma 2B12F6, which produce monoclonal antibody against SA I/II of Streptococcus mutans. METHODS: The immunoglobulin variable region gene of heavy chain of 2B12F6 was amplified and cloned into pUC18 by using PCR technique and gene engineering technique, and then the gene sequence was analyzed by Sanger's method. RESULTS: The VH gene segment was 360 base pairs in length and coded 118 amino acids, and the homology of framework of VH gene and mouse VH gene published was 70%, which accorded with the feature of mouse VH gene. CONCLUSION: The VH gene gained from 2B12F6 could provide the possibility of construction of gene engineering antibody against SA I/II of Streptococcus mutans.

Amino Acid Sequence↗