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Biomedical subjects

B Wang

Publications and source records attributed to B Wang.

At least 829 records · Page 46Linked to original sources
PubMed1993

[The changes in the levels of angiotensins and angiotensin converting enzyme and effects of captopril in patients with hypoxic pulmonary hypertension].

The levels of angiotensin I, II (ATI, II) and angiotensin converting enzyme (ACE) were measured in 28 patients with hypoxic pulmonary hypertension and 23 normal individuals. The effects of captopril were observed in 8 of 28 patients. The results showed that the average level of ATII in the patients was significantly higher than that in normal control (P < 0.05), but the average level of ACE in the patients was significantly lower than that in the controls (P < 0.05). In 8 patients, after the use of captopril, an ACE inhibitor, for two weeks, the levels of ATII, ACE and mean pulmonary arterial pressure (mPAP) were markedly decreased (P < 0.05). But the other 20 patients treated with antibiotics, antiasthmatics, diuretics and oxygen therapy for two weeks did not show any alterations in the levels of ATII, ACE and mPAP.

Aged↗
PubMed1993

[Development of hybridomas secreting monoclonal anti-idiotypic antibodies that bear the internal image of the terminal trisaccharide of PGL-I].

Two hybridomas designated as F7B7 and F7B9 secreting monoclonal anti-idiotypic antibodies against terminal trisaccharide of PGL-I were developed by fusion of SP2/0 cells and spleen cells of BALB/c mouse immunized with mouse monoclonal anti-trisaccharide of PGL-I (MAb1-E10F1). To characterize the F7B7, the following results were obtained. First, F7B7 reacted with MAb1-E10F1 specifically. Secondly, the cross ELISA neutralizing tests gave positive results. The binding of anti-trisaccharide positive serum with trisaccharide (contained in semi-synthetic antigen, NT-O-BSA) was inhibited F7B7 and the degree of inhibition showed dose-dependent manner. The binding of anti-trisaccharide positive serum with F7B7 was inhibited by NT-O-BSA and the degree of inhibition also showed dose-dependent manner. It was concluded that the hybridoma F7B7 is able to secrete monoclonal anti-idiotypic antibodies that bear the internal image of trisaccharide of PGL-I. The potentials and advantages of monoclonal anti-idiotypic antibody F7B7 as surrogate antigen in the serodiagnosis of leprosy have been discussed.

Animals↗
PubMed1993

Characteristics of intrathymic B cells in normal and chimera mice.

A subpopulation of B cells express Ly-1 (CD5 in human) antigen that is usually expressed on cells of T-cell lineage. This Ly-1+ B cell subpopulation (B1) has a quite different characteristic from the major Ly-1- B cell population (B2), and their physiological role and the functions under pathological conditions have not been thoroughly studied. In the present investigation, characteristic of intrathymic B cells from a variety of mouse strains and allogeneic bone marrow chimeras was studied. B cells were found in the thymic medulla as diffusely scattered pattern among the majority of mouse strains studied. By contrast, in SJL/J and AKR/J mice, intrathymic B cells were arranged in clusters within the medulla, and the proportion of Ly-1+ B cells in the B cell population was significantly lower than that seen in other strains of mice. Further, when B cells in thymi from allogeneic bone marrow chimeras were analyzed, the intathymic B cells were fully reconstituted with donor bone marrow-derived cells but showed the same distribution pattern and phenotype as those of the recipients. These findings indicate that differences in the distribution pattern of a certain B cell subpopulation seen among various mouse strains are determined by the radio-resistant recipient environment (thymic stroma).

Animals↗
PubMed1993

[Effect of electrical stimulation of hyperstriatum on nucleus dorsalis intermedius ventralis anterior thalami somatosensory units in pigeon].

Discharges of 88 somatosensory units in the nucleus dorsalis intermedius ventralis anterior thalami (DIVA) in response to afferent impulses of radial nerve on 55 urethane anesthetized pigeons were recorded and analysed. Among the 88 units, part of them also responded to the stimulation of sciatic nerve. Following electrical stimulation of somatic projecting area of hyperstriatum, the spontaneous discharges and the responses of DIVA somatosensory units to radial inputs were obviously inhibited and the degree of inhibition was linearly correlated with the frequency and intensity of stimulation. The inhibitory effect on the responses to radial inputs may cause an increase in latency and a decrease in number of spikes. These results indicate that the DIVA certainly belongs to somatosensory system, and the somatic projecting area of hyperstriatum has a descending inhibitory effect on the DIVA somatosensory units. The hyperstriatum may thus exert feedback control over its sensory inputs through descending inhibition. It appears that the functional connection between the highest region of central nervous system and thalamus in avian is similar to that of mammal.

Afferent Pathways↗
PubMed1992

Difference in the response of neu and ras oncogene-induced rat mammary carcinomas to early and late ovariectomy.

Rat mammary carcinomas were induced by directly inserting activated neu or ras genes into in situ rat mammary ductal cells using replication-defective retroviral vectors. neu was over 200 times more potent than ras in inducing rat mammary carcinomas. Ovariectomy 2 days postinfection dramatically reduced the occurrence of carcinomas induced by neu and extended their latency. In general, early ovariectomy had much less effect on the occurrence of carcinomas induced by ras and had no significant effect on their latency. Carcinomas induced by neu in ovariectomized rats had down-regulated estrogen receptor and progesterone receptor, while those induced by ras had only down-regulated progesterone receptor. Fully progressed mammary carcinomas in intact rats induced by both neu and ras had a similar response to ovariectomy, with an approximate regression rate of 60%. These data suggest that the activation of ras, but not neu, can replace at least some functions performed by ovarian hormones in the early phases of mammary carcinogenesis. These data also suggest a role for antiestrogen drug therapy in the prevention of neu-associated breast cancer.

Animals↗
PubMed1992

Overlap of somatic and visual response areas in the Wulst of pigeon.

The somatic and visual response areas of the Wulst were investigated electrophysiologically in pigeons. Somatosensory neurons are distributed in the hyperstriatum accessorium (HA), the hyperstriatum intercalatus superior (HIS) and the hyperstraitum dorsal (HD), mainly in HA. The radial nerve response area is relatively larger and overlaps the sciatic nerve area. Visual neurons are located in HA, especially the more superficial part of HA. In the Wulst, the somatic response area overlaps the visual area and there is somatosensory-visual convergence.

Animals↗
PubMed1992

Epidermal Langerhans cells from normal human skin bind monomeric IgE via Fc epsilon RI.

Human epidermal Langerhans cells (LC) bearing IgE are found in disease states associated with hyperimmunoglobulinemia E. When studying the mechanism(s) underlying this phenomenon, immunohistology revealed that a majority of epidermal LC from normal skin of healthy individuals can specifically bind monomeric IgE. IgE binding to LC could neither be prevented by preincubation of the tissue with monoclonal antibodies (mAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32, nor by the addition of lactose. However, binding could be entirely abrogated by preincubation with the anti-Fc epsilon RI alpha mAb 15-1, which interferes with IgE binding to Fc epsilon RI alpha gamma transfectants. These observations indicated that IgE binding to epidermal LC is mediated by Fc epsilon RI rather than by CD23, CD32, or the D-galactose-specific IgE-binding protein. This assumption gained support from our additional findings that: (a) the majority of LC exhibited distinct surface immunolabeling with the anti-Fc epsilon RI alpha mAbs 15-1 and 19-1, but not with any of eight different anti-Fc epsilon RII/CD23 mAbs; and (b) transcripts for the alpha, beta, and gamma chains of Fc epsilon RI could be amplified by polymerase chain reaction from RNA preparations of LC-enriched, but not of LC-depleted, epidermal cell suspensions. In view of the preeminent role of Fc epsilon RI crosslinking on mast cells and basophils in triggering the synthesis and release of mediators of allergic reactions, the demonstration of this receptor on epidermal LC may have important implications for our understanding of allergic reactions after epicutaneous contact with allergens.

Animals↗
PubMed1992

Fc epsilon RI mediates IgE binding to human epidermal Langerhans cells.

In a recent series of experiments, we observed that epidermal Langerhans cells (LC) of healthy, non-atopic individuals have the capacity of specifically binding monomeric serum or myeloma IgE. IgE-binding to LC could neither be prevented by pre-incubation of the cryostat sections with monoclonal antibodies (MoAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32 nor by the addition of excess amounts of lactose, but could be entirely abrogated by pre-incubation with the anti-Fc epsilon RI MoAb 15-1. A direct testing of the anti-Fc epsilon RI MoAb 15-1 and 19-1 on cryostat sections in an indirect immuno-double-labeling technique showed that, in contrast to eight different anti-Fc epsilon RII/CD23 MoAb, these MoAb react with the majority of CD1a-bearing epidermal cells. At an ultrastructural level, 15-1 immunogold-labeling in the epidermis was confined to the surface of cells exhibiting Birbeck granules. In further experiments, we were able to amplify by polymerase chain reaction (PCR) technology transcripts for the alpha, beta, and gamma chains of Fc epsilon RI from LC-enriched epidermal cells and dermal cells, but not from LC-depleted epidermal cells. Transcripts for the mast cell enzyme tryptase were exclusively found in dermal cell-derived RNA preparations, thus excluding a contamination of the LC-enriched epidermal cell preparations by dermal mast cells. Collectively, these data show that epidermal LC, but not other epidermal cells, express Fc epsilon RI molecules.

Dermatitis, Atopic↗
PubMed1992

Hematological parameters and visceral lesions relationships in rabbit viral hemorrhagic disease.

Twenty rabbits were inoculated with a suspension of Viral Hemorrhagic Disease virus. Hemostatic functions were assessed every sixth hour from 6 to 60 hours post-inoculation. Tissue samples obtained at the same intervals allowed the study of the development of lesions throughout the experiment. Biological signs of Disseminated Intravascular Coagulation (DIC) were detected on and after 30 h post-inoculation and consisted of prolonged One Stage Prothrombin Time and Activated Partial Thrombin Time, the decrease of factors V, VII, and X and high levels of soluble fibrin monomer complexes and D-dimers. A reduction of thrombocyte numbers, heterophils and lymphocytes was associated. The close association of DIC and necrotizing hepatitis lesions suggested the hepatic lesions to be the most important DIC triggering factor. Other mechanisms are discussed.

Animals↗
PubMed1992

[Effect of injection of enkephalin and bestatin in caudate-putamen on operant conditioning in rats].

Female Wistar rats were trained in a Skinner-box, 30 trials per day in a dark room to establish operant defence conditioning. Training started with a light (15 s), then combined with footshock for further 8 s. When the rats learned to press the key to avoid footshock within 15 s, conditioned response was considered established. After the rats reached a conditioning rate (CR) above 80% for 5 days, cannulae were implanted into caudate-putamen. Two to three days later, Met-enkephalin (MEK) or bestatin (an aminopeptidase inhibitor) was injected bilaterally into caudate-putamen. 30 min, 2 h, 24 h and 48 h after injection, conditioning tests were conducted, with each session consisting of 30 trials. Control experiments were done when 0.9% NaCl (NS) was injected. After injection of NS, CR maintained above 80% in all 4 test sessions. MEK (60 ng/rat) or bestatin (10 micrograms/rat) significantly lowered the CR during the 30 min and 2 h test session. In the latter case, the latency (L) was also prolonged. However both CR and L returned to the control level in the 24 h and 48 h test sessions. Naloxone (2 mg/kg, i.p.) blocked the conditioning-depression effect of bestatin. No significant alteration was seen in locomotor activity after MEK or bestatin injection. The results suggest that enkephalin in caudate-putamen may be involved in the regulation of retrieval of conditioning. Bestatin mimics the effect of MEK on conditioning reflex probably by increasing production of endogenous enkephalin.

Animals↗
PubMed1992

[Studies on the chemical constituents of Glycyrrhiza pallidiflora Maxim].

A species of the genus Glycyrrhiza, G. pallidiflora Maxim, growing in Jiangsu and Hebei Provices of China, has been little studied before on its chemical constituents. This paper reports the isolation and chemical elucidation of five compounds from this plant, one of them is a new compound named glypallichalcone (P-2). Their chemical structures were elucidated by means of chemical and spectrometric analysis (UV, IR, MS, 1HNMR and 13CNMR) and were first reported to be present in this plant. Glypallichalcone (P-2), was found to be 4-hydroxy-2,4'-dimethoxy-chalcone. The known compounds were identified to be 4'-O-methylcoumestrol (P-1), N-acetyl-glutamic acid (P-3), formononetin and beta-sitosterol (P-5).

Chalcone↗
PubMed1992

Cloning, characterization and partial sequence analysis of the 5'-flanking region of bovine alpha-sl casein gene.

We have isolated a clone from a EMBL3 constructed bovine genomic library using a PCR-generated DNA fragment as a probe covering-660bp to + 158 bp of boving alpha-sl casein gene. The results obtained from hybridization assay, restriction endonucleases map and partial DNA sequence analysis indicated that the cloned fragment spanned 5.7kb of the first part of the gene and 8.0 kb of its upstream flanking region. Some divergent restriction endonuclease recognition sites and a few mutations and deletions were found in exons, introns and 5'-flanking region of the gene we cloned when compared with the PCR-generated fragment and those which had been published [6,10]. All the deletions occurred at repeat sequences.

Animals↗
PubMed1992

[Studies of outer membrane protein profiles by SDS-PAGE for Campylobacter jejuni in an epidemiological investigation].

The characteristics of outer membrane protein profiles of 41 strains of Campylobacter jejuni from various sources by SDS-PAGE was studied. Seven and nine OMP patterns were differentiated respectively by the presence or absence of six outer membrane protein bands and by the number and size of the molecular weight of the major protein bands. Comparing the OMP patterns of the strains from human with those from animals, the authors inferred that chickens and other animals might be one of the sources for the human infection of Campylobacter jejuni in this district. A comparison between the OMP patterns of the strains from diarrheic children and those from healthy carriers suggested that the pathogenesis of Campylobacter jejuni be possibly associated with the outer membrane proteins. Using the techniques, the authors studied the infection of Campylobacter jejuni in a nursery. The result showed the infection was sporadic and of multi-sources, as evidenced by the multi-patterns of the outer membrane protein profiles. It also indicates that the person-to-person transmission plays a significant role in the infection of Campylobacter jejuni.

Animals↗
PubMed1992

[Effects of GTW and T4 from Tripterygium wilfordii Hook f. on LH cells in male rat pituitary glands].

Using anti-beta-LH monoclonal antibodies, studies were undertaken to assess the effects of the glycosides (GTW) and T4 from Tripterygium wilfordii Hook f. on LH cells in male rat pituitary glands using immunohistochemical methods and ultrastructural observation. The results showed that there were more vacuoles in the cytoplasm of LH cells and the color density of immunohistochemical staining was much stronger in the treated groups than that in the control group. Electron microscopic results showed that the nulei of LH cells were shrunken and the Golgi complexes and the rough endoplasmic reticula were largely expanded in the treated groups. The mechanism of these changes is similar to that in "castration cells."

Animals↗
PubMed1992

[Generation of monoclonal antibodies (McAbs) against human luteinizing hormone (hLH) in a methylcellulose semi-solid medium].

McAbs against hLH were generated by a facile hybridoma technique according to the methods of Davis and Lee, et al. After routine immunization and cell fusion, the cells were plated in a semi-solid medium containing methylcellulose and HAT. Five to seven days later, visible clones were removed for subculture in DMEM liquid medium containing 15% FCS and then screened by ELISA. As a result, 12 hybrid cell lines secreting McAbs to the LH-B subunit were obtained. These Abs have been used in clinical diagnostic and immunohistochemical work, showing good results. The advantages of the semi-solid medium in preparing McAbs are discussed.

Animals↗
PubMed1992

Cloning, mapping, and sequencing of 3' and its flanking region of bovine alpha-s1 casein gene.

A positive clone was isolated from a bovine genomic library in EMBL3 with the probe of alpha-s1 casein gene cDNA. The results from both restriction endonuclease digestion and Southern hybridization probed with the upstream and downstream fragments from the termination codon of bovine alpha-s1 casein gene cDNA suggested that the clone contained 3.5 kb downstream and 10.2 kb upstream fragments from the termination codon of alpha-s1 casein gene. Some divergences in restriction endonucleases sites, a few deletions, and many point mutations were found in introns and exons when compared with those which were published.

Animals↗