Restriction endonuclease from thermophilic bacterial species. IV. Isolation and characterization of BpuB5I.
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Bacillus↗
Biomedical subjects
Y Z Wang
Publications and source records attributed to Y Z Wang.
Ph-negative and bcr-negative atypical chronic myelogenous leukemia: biological features and clinical outcome.
We report the clinical, hematologic, cytogenetic, and molecular characteristics of 13 patients with Philadelphia-negative (Ph-), bcr-negative atypical chronic myelogenous leukemia (CML). In the majority of cases, the phenotypic features at presentation resembled those of typical CML. However, these patients presented with a higher median age, lower median hemoglobin levels, and lower leukocyte and platelet counts than patients with Ph-positive CML. Cytogenetic analysis showed an abnormal karyotype in only one case. Southern blot investigation, using probes exploring the entire M-bcr region, demonstrated the absence of genomic bcr-abl rearrangements. The assessment of clonality in five patients (study of X-methylation patterns in females heterozygous at the DXS255 locus) indicated the proliferation of a monoclonal cell population. Disease evolution was mostly characterized by bone marrow failure, extramedullary infiltrates, and poor response to chemotherapy, without evidence of overt acute transformation. Our observations suggest that some hematologic and clinical features and the modalities of disease progression are presently the most helpful factors in distinguishing these bcr/abl-negative patients from those with typical bcr+CML. The differences existing also with chronic myelomonocytic leukemia (CMMoL), allow the consideration of ph-/bcr- CML as a separate entity, the nature of which remains to be elucidated.
Cytogenetics↗
Loss of absorptive capacity for sodium and chloride in the colon causes diarrhoea in Potomac horse fever.
Ehrlichia risticii, an obligate intracellular bacterium in the family Rickettsiaceae, causes Potomac horse fever which is often associated with severe watery diarrhoea. The mechanism of the diarrhoea is unknown. The aim of this study was to determine whether sodium and chloride transport, morphology and cyclic adenosine 3', 5'-monophosphate (cyclic AMP) content of colonic mucosa was altered in E risticii-infected horses. Mucosa-submucosa sheets from the large and small colon of nine infected and seven to nine uninfected horses were set up in Ussing chambers for measurement of short-circuit current and transepithelial 22Na and 36Cl fluxes. Uninfected tissues absorbed both sodium and chloride whereas absorption of sodium and chloride was abolished in infected tissues. Bethanechol and histamine evoked a concentration-dependent increase in short-circuit current in both groups, but the responses were attenuated at all concentrations in infected horses. Slight focal degeneration of colonic epithelial cells and loss of microvilli from glandular epithelial cells occurred in infected horses. There was a significant increase in cyclic AMP content in colonic mucosa of infected animals. The results suggest that E risticii infection induces focal microscopic degeneration of epithelial cells and an increase in intracellular cyclic AMP in colonic mucosa. These alterations are associated with malabsorption of sodium and chloride and could cause diarrhoea.
Animals↗
Neuroimmune interactions: role for cholinergic neurons in intestinal anaphylaxis.
The role of cholinergic neurons in mediating chloride secretion in anaphylaxis was assessed in muscle-stripped segments of distal colon from guinea pigs immunized to bovine milk. beta-Lactoglobulin evoked a concentration-dependent increase in short-circuit current (Isc) in immune, but not nonimmune, tissues. The Isc response to beta-lactoglobulin was reduced by piroxicam, pyrilamine, and cimetidine. Tetrodotoxin and atropine reduced the Isc response to beta-lactoglobulin in immune animals, whereas mecamylamine and ICS 205-930 were ineffective. beta-Lactoglobulin evoked a concentration-dependent increase in acetylcholine (ACh) release in immune, but not nonimmune, animals. In immune tissues after challenge with beta-lactoglobulin, ACh release paralleled the change in Isc. Piroxicam, cimetidine plus pyrilamine, or a combination of piroxicam, cimetidine, and pyrilamine significantly reduced the release of ACh after beta-lactoglobulin challenge. Histamine, dimaprit, and prostaglandins E2 evoked an increase in ACh release. These results suggest that beta-lactoglobulin releases prostaglandins and histamine probably from mast cells. Secretory responses that occur when immune animals are challenged with beta-lactoglobulin result, in part, from activation of cholinergic neurons that utilize muscarinic synapses for transfer of signals to the epithelium.
Acetylcholine↗
Multidrug resistance activity in human lymphocytes.
The multidrug resistance gene (mdr1) is a member of the recently described ATP binding cassette (ABC) superfamily of transporters. Family members include: (1) the cystic fibrosis transmembrane conductance regulator gene; (2) the hlyB gene of bacteria, and (3) the histocompatibility antigen modifier (HAM) gene. The level of expression of mdr1 correlates with multidrug resistance (MDR), the ability of cells to efflux otherwise toxic doses of several chemotherapeutic agents. MDR activity is also associated with the efflux of cationic lipophilic compounds such as the fluorescent dye rhodamine 123. Recently it was reported that normal lymphocytes efflux rhodamine 123, suggesting that these cells possess MDR-like activity due to the expression of mdr1. In this study, using two-color flow cytometric analysis, we observed that the ability to efflux rhodamine 123 was heterogeneous among human lymphocyte subsets in the order of CD8 greater than CD4 greater than CD2O. Rhodamine 123 efflux and accumulation in lymphocytes was sensitive to the known MDR reversing agents, verapamil and Solutol HS 15. Collectively, these data suggest that an MDR-like transport system is present in normal lymphocytes and may be important for trafficking of molecules involved in lymphocyte function.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Bone remodeling in hypervitaminosis D3. Radiologic-microangiographic-pathologic correlations.
To investigate the mechanism of bone changes in hypervitaminosis D3, we compared contact radiographs, microangiograms by injection of Chinese ink, and corresponding histopathologic macrosections of 66 rabbits that received different doses of vitamin D3. In early stages, radiographs showed subperiosteal bone resorption and porotic cortical bone. The corresponding microangiograms showed proliferating vessels in the periosteum and cortical bone with associated dilatation of the Haversian and Volkmann's canals. When metastatic calcification fills these intracortical caverns or the intertrabecular spaces in the metaphysis and physis, the bone shows a diffuse increased density on radiographs. A dense band in the metaphysis reflects a thickening of calcified chondromatrix due to a hypotrophy of the distal metaphyseal capillaries. Six to 12 weeks after vitamin D3 withdrawal, radiographs showed further increased density of the cortical bone, due to newly formed bone and metastatic calcification. Alternating bands of increased and decreased density in the metaphysis and physis reflect the reinvasion of normal vasculature between growth cartilage and calcified chondromatrix, with normalization of endochondral ossification.
Angiography↗
Chronic myeloid leukaemia lymphoid blast crisis. Relevance of molecular analysis at the bcr and immunoglobulin heavy chain gene level in monitoring response to therapy and residual disease.
Southern blot analyses were performed in sequential DNA samples from 4 patients with Ph' + chronic myeloid leukaemia (CML) who underwent lymphoid or mixed blast crisis (BC). Genomic rearrangements at the breakpoint cluster region (bcr) and immunoglobulin heavy chain (IgH) gene level provided, in these cases, a sensitive and specific evaluation of response to therapy both in terms of blasts and Ph' + cell suppression. Recurrent BC was molecularly characterized in the 4 patients, showing each time identical individual specific DNA rearrangement patterns. Residual blasts were detected in 2 cases during intervening chronic phases by IgH rearrangements. Such findings highlight the specificity of these molecular markers, clearly indicating the failure of ablative therapy in eradicating the neoplastic clone. Finally, molecular and phenotypic identity in individual recurrent BC also suggested, in our cases, a lack of clonal evolution during disease progression.
Antineoplastic Agents↗
Neuroimmune regulation of colonic secretion in guinea pigs.
The role of submucosal neurons in anaphylactic-like responses in colonic epithelium from immunized guinea pigs was examined 6-8 wk after inoculation with 2 x 10(3) infective Trichinella spiralis larvae. Serosal addition of T. spiralis antigen (20 micrograms/ml) to muscle-stripped segments of colon set up in flux chambers evoked a maximum increase in short-circuit current within 5 min in immune, but not nonimmune, guinea pigs. Quercetin, a membrane-stabilizing drug, and pyrilamine, a histamine H1 receptor antagonist, attenuated epithelial responses evoked by T. spiralis antigen. Antigen-induced epithelial responses were reduced by neural blockade with tetrodotoxin and by the muscarinic receptor antagonist atropine but not by blockade of nicotinic receptors with mecamylamine. Antigenic challenge of colonic mucosa from immune guinea pigs enhanced the secretory responses to endogenously released neurotransmitters evoked by electrical field stimulation and substance P. In the presence of antigen, the tetrodotoxin-insensitive component of the carbachol response was enhanced and was reversed by quercetin but not pyrilamine. The results suggest that submucosal cholinergic nerves play a role in mediating the rapid epithelial responses evoked by worm antigen in the colonic mucosa of T. spiralis-immune guinea pigs. Interaction of immunological mediators with neurotransmitters in the submucosal plexus augments the secretory mucosal response triggered by T. spiralis in immunized hosts.
Animals↗
Neural 5-hydroxytryptamine receptors regulate chloride secretion in guinea pig distal colon.
The effects of 5-hydroxytryptamine (5-HT) on epithelial short-circuit current (Isc) were determined and related to the 5-HT effects on electrical and synaptic behavior of neurons in the submucosal plexus of the guinea pig colon. 5-HT evoked a biphasic increase in Isc that was reduced by bumetanide, Cl(-)-free solutions, atropine, and mecamylamine and abolished by tetrodotoxin. The 5-HT response was mimicked by 2-methyl-5-HT, but not by 5-hydroxyindalpine, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane, and 5-methoxytryptamine (5-MeOT). ICS 205-930 suppressed the 5-HT response. Electrical field stimulation of submucosal neurons evoked an increase in Isc indicative of Cl- secretion that was reduced by 5-MeOT and enhanced by 2-methyl-5-HT. Application of 5-HT to submucosal neurons by micropressure ejection resulted in membrane depolarization, augmented excitability, and repetitive spike discharge. The depolarization was biphasic, consisting of rapidly and slowly activating components. The rapidly activating component was suppressed by ICS 205-930. Fast excitatory postsynaptic potentials evoked by electrical stimulation of interganglionic connectives were suppressed by 5-HT and 5-MeOT. These results suggest that 5-HT activates 5-HT3 receptors, which mediate fast excitatory responses in submucosal neurons, leading to release of acetylcholine at nicotinic and muscarinic synapses and stimulation of Cl- secretion. Presynaptic inhibition suppresses acetylcholine release and results in attenuation of neurally evoked Cl- secretion.
Animals↗
[A study of IL-2 activity on lung cancer].
By using thymocytes of mice as target cells in bioassay, IL-2 production activity was investigated in 24 lung cancer patients, 24 noncancerous pulmonary lesions as well as 20 normal individuals. Fourteen cancer patients were reexamined after the first course of chemotherapy. This research demonstrated that: 1. PBL capable of IL-2 production in lung cancer patients were rare in comparison with benign disease or normal control. 2. IL-2 activity was markedly enhanced by chemotherapy. It is suggested that IL-2 is a good indicator for estimating the efficacy of treatment of lung cancer.
Adult↗
Reassessment on roentgenologic signs of early rickets. Roentgenopathologic correlations of 52 en block specimens.
Correlation of the X-ray manifestation and the en bloc sections of 52 wrists of infants and children aged from 0-4 years from autopsy was carried out to identify the real X-ray signs of rickets. Simple ill-defined provisional calcified zone (PCZ), enlargement of head of ulna, shallow saucer-shaped and undulant or multilaminar PCZ are normal in variation. The signs of early rickets included marginal spur, saucer-shaped deformity, ill-defined and disordered trabeculae under PCZ, mild brush appearance and osteoporosis. However, only when five of the above mentioned criteria were met at the same time, can early rickets be diagnosed.
Child, Preschool↗
Application of pyridostigmine in evaluation of growth hormone reserves in children and adolescents.
There is evidence that the cholinergic system positively modulates growth hormone (GH) secretion. In the present study, we observed the effects of cholinergic enhancement by pyridostigmine (PD), a cholinesterases inhibitor, on GH release in both normal (n = 13) and GH deficient children and adolescents (n = 10). Responses of GH to insulin hypoglycemia (Ins) were also observed. In the normal subjects, PD-induced serum GH peak level was significantly higher than that induced by Ins (P less than 0.01), while the GH level in the patients with pituitary dwarfism showed no increase in both tests. This study indicates that PD test may be considered a sensitive dynamic test in evaluating pituitary function of GH secretion in children and adolescents.
Adolescent↗
Effects of tetrodotoxin on chloride secretion in rabbit distal colon: tissue and cellular studies.
The effects of tetrodotoxin (TTX) were examined in muscle-stripped segments of rabbit distal colon and in cells of isolated colonic crypts. Electrical field stimulation (EFS) of the submucosa/mucosa evoked an increase in short-circuit current (ISC) that was due to an increase in chloride secretion. The EFS-evoked response was reduced 81% by 10(-7) M TTX and 30% by 5 X 10(-6) M atropine. Vasoactive intestinal peptide (VIP), carbachol, aminophylline, and 1,1-dimethyl-4-phenylpiperazinium increased ISC. Bumetanide reduced the responses to neural stimulation, aminophylline, and VIP. To determine whether TTX had direct effects on crypt epithelial cells, crypts were isolated and cells were impaled with microelectrodes. Mean resting potential (Vbl) was -67 +/- 1.1 mV (n = 63). VIP and aminophylline depolarized Vbl by 34 +/- 4.6 (n = 13) and 34 +/- 3.5 mV (n = 18), respectively. TTX had no significant effect on resting Vbl or on the responses to VIP or aminophylline. We conclude that stimulation of submucosal neurons in the rabbit distal colon evokes a TTX- and bumetanide-sensitive increase in net chloride secretion that is dependent on the release of acetylcholine and other secretory neurotransmitters. Electrophysiological studies rule out a direct effect of TTX on colonic crypt cells.
Amiloride↗
Histamine augments colonic secretion in guinea pig distal colon.
We tested the hypothesis that the role of histamine in the control of intestinal secretion is mediated by prostaglandins (PGs). The effects of histamine on ion transport were examined in muscle-stripped sheets of mucosa/submucosa set up in flux chambers. Histamine evoked a transient concentration-dependent increase in short-circuit current (Isc) that was reduced by the Cl- transport inhibitor bumetanide. Histamine also caused the release of PGE2. The Isc response to histamine was reduced by indomethacin and piroxicam, which block PG formation, but not by nordihydroguaiaretic acid, which prevents production of lipoxygenase products. 2-Methylhistamine, but not dimaprit, evoked a concentration-dependent increase in Isc. The Isc response to histamine was reduced by the H1-blocker pyrilamine, but not by the H2-antagonist cimetidine. In addition to its direct effect, histamine augmented the responses of endogenously released neurotransmitters with and without indomethacin and hexamethonium. Tetrodotoxin (TTX) reduced the Isc response to 10(-3) M histamine. In the presence of TTX, exogenous histamine amplified the responses to PGs, vasoactive intestinal polypeptide, 2-chloroadenosine, bethanechol, and carbachol. These results suggest that histamine acts at H1-receptors on cells within the gut to mediate intestinal Cl- secretion in part by releasing PGs and by augmenting the actions of endogenously released neurotransmitters. Our results indicate that histamine has a role in the regulation of colonic transport function.
2-Chloroadenosine↗
H2 receptors mediate cyclical chloride secretion in guinea pig distal colon.
We tested the hypothesis that histamine mediates ion secretion in the guinea pig distal colon by stimulating H2 receptors on submucosal neurons. Serosal addition of histamine evoked a transient increase in short-circuit current (Isc) followed by recurrent cyclical increases in Isc. The transient phase of the response was examined previously and was not investigated in these studies. Histamine (1.5-2.5 x 10(-5) M) evoked a peak increase in Isc of 177 +/- 25 microA/cm2 at intervals of 5 min for 1-2 h. The duration of each recurrent cycle averaged 2.1 +/- 0.3 min. The H2 agonist dimaprit evoked recurrent cycles that had larger amplitudes than those caused by histamine. In the presence of histamine or dimaprit, the amplitude of the first cycle of the response was always less than subsequent cycles, regardless of the initial concentration. The cyclical responses to histamine, 2-methylhistamine, or dimaprit were unaltered by the H1 blocker pyrilamine, were reduced by the H2 antagonist cimetidine, and were abolished by the neuronal blocker tetrodotoxin. Blockade of prostaglandin formation with piroxicam did not prevent the recurrent cycles. The recurrent cycles were inhibited by the chloride transport blocker bumetanide and by removal of chloride ions. Our results demonstrate that histamine mediates prolonged cyclical chloride secretion in the guinea pig distal colon by activating H2 receptors on submucosal neurons involved in regulation of epithelial chloride transport.
Animals↗
Metastatic calcification within bone. The main cause of osteosclerosis in hypervitaminosis D3. Radiologic-pathologic correlation.
Because the pathogenesis of osteosclerosis in hypervitaminosis D is still not well elucidated, the authors experimentally studied hypervitaminosis D3 in 66 rabbits by injecting different doses of vitamin D3. Contact radiographs of bone specimens showed various signs of osteosclerosis, including dense epiphyses and metaphyses, thickened bony articular surfaces, dense metaphyseal bands, modeling defects at the metaphysis, and dense and thickened cortical bone. The corresponding pathologic sections showed that conspicuous metastatic calcification coated the trabeculae and filled bone marrow cavity and caverns in the original but porotic cortical and periosteal new bone. Rather than being resorbed, the metastatic calcifications were embedded in a thick layer of newly formed bone 6 to 14 weeks after vitamin D3 withdrawal. This study suggests that in hypervitaminosis D3, the osteoblasts and bone marrow undergo degeneration, leading to necrosis and calcification. After vitamin D3 withdrawal, osteoblasts reappear and become overactive, leading to overossification.
Animals↗
[Detection of serum antibodies in jirds against antigens of Brugia malayi].
The indirect fluorescent antibody test (IFA) using the infective larva (L3), adult worm (A) and microfilaria (Mf) antigens was applied to detect anti-filarial antibodies in jirds (Meriones unguiculatus) infected with Brugia malayi. The antibodies against L3 appeared within 3 weeks after infection, followed by A and Mf. The serum antibody levels in the jirds with positive infection were compared with those in the jirds with negative infection. Before appearance of microfilaria, there was insignificant difference between these two groups. However, significant difference was observed after the appearance of microfilaria. The method of sonicating L3 and Mf fragment antigens used in this study is simple, and its results are easy to observe.
Animals↗