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Biomedical subjects

L Zhou

Publications and source records attributed to L Zhou.

At least 541 records · Page 30Linked to original sources
PubMed1994

Distribution of androgen receptor immunoreactivity in vasopressin- and oxytocin-immunoreactive neurons in the male rat brain.

Arginine vasopressin-immunoreactive (AVP-ir) neurons in the bed nucleus of stria terminalis (BST) and medial amygdaloid nucleus are very responsive to gonadal hormones. After gonadectomy, these neurons lose their AVP immunoreactivity and stop expressing AVP mRNA. Testosterone treatment reverses these changes, acting via androgen as well as estrogen receptor-mediated mechanisms. Although AVP-ir neurons contain estrogen receptor immunoreactivity, it is not known whether they also contain androgen receptor immunoreactivity. To answer this question, brains of male rats were stained immunocytochemically for AVP as well as for androgen receptors. In the BST and medial amygdaloid nucleus, respectively, 90.5% and 91.2% of the AVP-ir neurons contained androgen receptor immunoreactivity. In contrast, in the suprachiasmatic nucleus, the supraoptic nucleus, and the magnocellular portion of the paraventricular nucleus (PVN), none of the AVP-ir neurons contained androgen receptor immunoreactivity. In the ventral zone of the medial parvocellular part of the PVN (mpvPVN), 4.3% of the scattered AVP-ir neurons contained androgen receptor immunoreactivity. One of the control experiments, i.e. staining sections for oxytocin (OT) rather than AVP, revealed that although OT-ir neurons in the supraoptic and magnocellular portion of the PVN did not contain androgen receptor immunoreactivity, 52.5% of the OT-ir neurons in the mpvPVN did. The results suggest that androgens can bind to androgen receptors in AVP-ir neurons in the BST and medial amygdaloid nucleus, possibly to influence AVP expression. The results also suggest that androgens can bind to androgen receptors in AVP-ir and OT-ir neurons in the mpvPVN. The function of the latter interaction, however, is unclear.

Animals↗
PubMed1994

[Effects of acupuncture on antral G cells in patients with gastric disease].

It is well known that acupuncture is effective for treatment of gastric disease in human. We have observed the effect of acupuncturing "Zhongwan" "Neiguan" "Zusanli" on fluorohistochemical changes of G cells of antral mucosa in 42 patients with gastric disease. The results show that after acupuncture treatment the amount of fluorescent G cells and the fluorescent intensity of gastrin in the G cells were obviously decreased in patients with duodenal ulcer, as compared with that before acupuncture treatment. However, the amount of G cells was increased by acupuncture treatment in patients with chronic atrophic gastritis. These data indicate the acupuncture may regulate G cell from abnormal to normal condition in gastric mucosa of gastric disease.

Acupuncture Therapy↗
PubMed1994

[Flow cytometric analysis of DNA in giant cell tumor of bone].

The DNA content of 44 giant cell tumors (GCTs) was determined by flow cytometry and simultaneous analysis of cell surface antigens and cellular DNA was performed in two of these GCTs. Two grade III GCTs, one with lung metastases, were all aneuploid. Out of 42 grades I and II GCTs, 16 were aneuploid, statistically, there was no difference in proliferative activity and rate of aneuploidy between grade I and grade II GCTs, but significant difference between primary and local recurrent GCTs existed. After 5 passages in culture the proliferative rate of cells in 13 GCTs increased significantly, the rate of cells bearing GCT associated antigen stepped up and in 2 GCTs tested specially. All these findings demonstrate: (1) the morphological difference of these tumors was not remarkable (2) DNA determinations as an adjunct to conventional histopathologic assessment may provide objective clinically relevant information for prognosis, (3) tumor and non-tumor cells co-exist in GCTs and only tumor cells could survive in long-term culture in vitro.

Aneuploidy↗
PubMed1994

Role of vascular alpha-1 adrenoceptor subtypes in the pressor response to sympathetic nerve stimulation in the pithed rat.

Previous studies suggest that systemic arterial pressure is tonically regulated by the interaction of peripheral sympathetic nerves with vascular alpha-1A adrenoceptors in vivo. To explore this relationship further, the present study examined the inhibitory effect of selective alpha-1A [5-methylurapidil (5-MU) and nifedipine (NIF)] and alpha-1B [chloroethylclonidine (CEC)] antagonists on the pressor response to electrical stimulation (ES) of the spinal cord in pithed rats. Diastolic pressure changes were measured in the presence of 5-MU or CEC and compared with control responses. Pretreatment with 5-MU (0.5 mg/kg i.v.) significantly suppressed the ES pressor response (50-80% inhibition) at all stimulation frequencies. Likewise, NIF (inhibitor of calcium influx associated with alpha-1A adrenoceptor activation) selectively inhibited the pressor response to ES to the same degree as did 5-MU. CEC (25 mg/kg i.v.) also significantly shifted the ES response curve; however, this effect was mediated by activation of presynaptic alpha-2 receptors on sympathetic terminals because prior administration of idazoxan (5 mg/kg) prevented the inhibitory effect of CEC. Based on the potent inhibitory effects of 5-MU and NIF on the ES pressor response in the pithed rat, it was concluded that vascular alpha-1A adrenoceptors reside in the synaptic region of neurovascular junction where they are primarily activated by neuronal norepinephrine release.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Characterization of the gene for the human high affinity IgE receptor (Fc epsilon RI) alpha-chain.

The Fc epsilon RI couples the mast cell-surface binding of IgE and Ag to a complex series of intracellular events culminating in cell activation and degranulation. The alpha-chain of Fc epsilon RI constitutes the Ig-binding subunit of this heterotetrameric receptor, and is itself a member of the Ig gene superfamily. We have isolated a human genomic DNA clone containing the entire Fc epsilon RI alpha gene, and completely sequenced a region from 1257 bp 5' of the transcription start site, to 513 bp 3' of the last exon of the gene. As with the previously characterized rat and mouse genes, human Fc epsilon RI alpha consists of five exons and four introns, and spans 5889 bp of genomic DNA. The splice donor and acceptor sites deduced by comparison with the cDNA sequence corresponded exactly to the locations found in analogous rodent genes. By mapping the 5' end of Fc epsilon RI alpha transcripts we found three major transcription initiation sites 24, 27, and 29 bp upstream of the ATG translation initiation codon. As well, several longer minor transcripts were seen, with a maximum of 60 nt of 5'-untranslated sequence. About 650 bp of DNA upstream of the ATG translation initiation codon were compared among human, rat, and mouse Fc epsilon RI alpha sequences in search of common motifs that might mediate conserved regulatory interactions with DNA binding proteins. A 172-bp region of the human Fc epsilon RI alpha 5'-flanking sequence was highly conserved in both rodent species. Further studies will be required to determine whether these or other sequences are involved in Fc epsilon RI alpha gene regulation.

Base Sequence↗
PubMed1993

The replication fate of R- and S-styrene oxide adducts on adenine N6 is dependent on both the chirality of the lesion and the local sequence context.

In order to deduce the biological fate of adducts formed by the reaction of styrene oxide, a suspected carcinogen, with DNA, four oligodeoxynucleotides were synthesized which contained either R- or S-styrene oxide lesions on the N6 position of neighboring adenines within the human N-ras codon 61. When these adducted oligodeoxynucleotides were ligated into the single-stranded vector M13mp7L2 and the modified DNA used to transform repair-deficient Escherichia coli, the resultant plaque-forming abilities were found to vary as much as 300-fold, depending on the stereochemical configuration of the styrene oxide lesion and the sequence context in the vicinity of the damage. The frequency of mutations caused by the various styrene oxide adducts were similarly dependent on both their chirality and local sequence context. Oligodeoxynucleotide templates bearing these same four adducts were also constructed in order to evaluate their replication in vitro by the Klenow fragment. Three of the four styryl-modified templates yielded significant levels of fully extended primer upon polymerization. In contrast, the template containing R-styrene oxide at the second position of N-ras 61 was a very poor substrate for replication, a result which correlates well with the observed lethality of this lesion in vivo.

Adenine↗
PubMed1993

Brn-3b: a POU domain gene expressed in a subset of retinal ganglion cells.

A search for POU domain transcription factors in human retina cDNA has led to the identification of Brn-3b, a class IV POU domain protein. Immunohistochemical experiments show that chicken, mouse, rabbit, monkey, and human retinas contain Brn-3b exclusively within a subpopulation of ganglion cells. In the adult mouse brain, Brn-3b is found only within cells in the deep layers of the superior colliculus, in the dorsal periaqueductal gray, and in a small cluster of cells in the brain stem near the area postrema. During the immediate postnatal period, cells containing Brn-3b are distributed in a number of regions within the brain stem and cerebellum. These data suggest that Brn-3b plays a role in determining and/or maintaining the identities of a small number of neurons, including a subset of visual system neurons.

Amino Acid Sequence↗
PubMed1993

Interactions of transforming growth factor-alpha and -beta and luteinizing hormone in the regulation of plasminogen activator activity in avian granulosa cells during follicular development.

This study examined the influence of transforming growth factor-alpha (TGF alpha), TGF beta, and LH on progesterone (P4) secretion and plasminogen activator (PA) activity in cultured avian granulosa cells from the first (F1), third (F3), and fifth and sixth (F5-6) preovulatory follicles during a 21-h incubation period. PA activity in the cell (PAc) and the medium (PAm) fractions was measured by fibrinolysis and fibrin overlay methods. P4 was determined by RIA. Basal PAc and PAm activities were highest in cell cultures from the less mature (F5-6) follicles and decreased as follicles matured to the F1 stage of development. PAc activity was greater than PAm activity regardless of the stage of follicular maturation. TGF alpha (0.1-10 ng/ml) increased PA activity in cultures of granulosa cells from F1, F3, and F5-6 follicles in a concentration-dependent manner. TGF alpha-induced PAc and PAm activities were observed by 6 and 15 h of incubation, respectively, and increased rapidly between 15-21 h. LH (100 ng/ml) attenuated TGF alpha-induced PA activity by 15 h in cultures of granulosa cells from F1 and F3, but not F5-6, follicles. Basal PA activities were unaffected by the gonadotropin. TGF beta (2-100 ng/ml) stimulated PAc activity in a dose-dependent manner only in cultures of granulosa cells from F5-6 follicles and significantly enhanced TGF alpha-induced PAc and PAm activities in cell cultures from F3 and F5-6, but not F1, follicles. Basal and growth factor-induced PAc and PAm activities corresponded to a mol wt of about 35 kDa, a value consistent with that of the low mol wt uPA species. TGF alpha and TGF beta, alone or in combination, had no effect on basal P4 secretion at all stages of follicular development. TGF alpha, however, decreased LH-induced P4 secretion in F1 and F3 cultures. These results demonstrate a tightly controlled interaction of TGF alpha, TGF beta, and LH in regulating PA activity and P4 secretion during follicular development in the domestic hen.

Animals↗
PubMed1993

[Changes of endogenous opioid peptides content in RPGL during acupuncture analgesia].

By push-pull perfusion technique and RIA of neuro-peptides, it was found that after 20 minutes' electroacupunture (EA), the release of LEK from the RPGL in the EA group was significantly higher than that in the control group (P < 0.05). The release of beta-EP from the RPGL in the EA group with higher efficacy was significantly higher than that in the control group (P < 0.05), but no significant changes were found in the EA group with lower efficacy. There was a positive correlation between the changes of release of LEK or beta-EP and the increase of pain threshold. The release of DynA1-13 tends to show a barely significant extent (P > 0.05). The results indicate that acupuncture analgesia is able to increase the release of LEK and beta-EP in the RPGL.

Acupuncture Analgesia↗
PubMed1993

Cardiovascular effects of chloroethylclonidine, an irreversible alpha 1B-adrenoceptor antagonist, in the unanesthetized rat: a pharmacological analysis in vivo and in vitro.

The role of vascular alpha 1B-adrenergic receptors in the regulation of arterial pressure (MAP) and heart rate (HR) was examined by assessing the effect of i.v. chloroethylclonidine (CEC; irreversible alpha 1B antagonist) in unanesthetized, normotensive Long-Evans rats. MAP, HR and the pressor response to i.v. phenylephrine (PE) were monitored for 24 hr after saline or CEC (15 mg/kg and 25 mg/kg) injection. Neither i.v. saline nor CEC affected MAP or HR throughout the course of the study, yet the PE response was maximally inhibited (> 75% at 15 min) by both doses of CEC. The PE response recovered by 2 hr at the 15-mg/kg dose but remained inhibited up to 4 hr at 25 mg/kg. At 24 hr, all cardiovascular parameters returned to control levels. CEC (100 microM, 30 min) produced irreversible blockade of norepinephrine-induced contractions in rat aortic rings; prazosin (10 nM) and sodium thiosulphate (1 mM, a reagent that inactivates aziridinium ions) reversed CEC's inhibitory effect. Precyclized CEC and its hydrolysis product beta-hydroxyethylclonidine (beta-HEC) poorly antagonized aortic alpha 1B-receptors. Ex vivo analysis of aortic rings from saline and CEC-treated rats showed that PE-induced contractions were shifted to the right and maximally depressed in a dose-dependent manner after 24 hr. These results suggest that 1) CEC produces long lasting blockade of alpha 1B-adrenoceptors in vitro and in vivo via formation of an aziridinium ion intermediate and 2) vascular alpha 1B-adrenoceptors are not coupled to the tonic physiological regulation of MAP in the rat.

Adrenergic alpha-Antagonists↗
PubMed1993

[Development of intercellular junction in the human vestibular receptors. A freeze-fracture study].

The intercellular junctions, especially the tight junctions of the inner ear end-organs are considered to act as a barrier to maintain gradients of ions between the endolymph and the perilymph. Thus, the intercellular junctions are of great importance for the function of the inner ear. We have studied the development of intercellular junctions in vestibular end-organs in order to establish a morphological basis for better understandings of the key stage of the development of vestibular end-organs. In the present article, the development and maturation of intercellular junctions in human vestibular receptors were observed with freeze-fracture technique. Junctional complex was already present during 8 weeks of gestation. During 8-11 weeks, a rapid development was seen in the intercellular junctions, so that this period seemed to be the key stage in the development and maturation of intercellular junctions. By the end of 11 weeks, the intercellular junctions had possessed the mature appearance as those seen in adults.

Epithelium↗
PubMed1993

[Generation and characterization of monoclonal antibody GCF-5 to human giant cell tumor of bone].

Hybrid cell line has been derived from fusion of mouse myeloma (Sp2/0-Ag14) cell and spleen cell from mouse which was immunized with cultured cells of giant cell tumor of bone (GCT). Hybrid cells produce monoclonal antibody against GCT associated antigen in the surface of the tumor cells. The monoclonal antibody was detected by immunoperoxidase staining and was designated by GCF-5. There were more than eighty per cent of tested GCT which showed this antigen. It had no cross reaction with many kinds of normal tissue, HLA antigen, alpha-Fetal Protein, Carcino-Embryonic Antigen and beta-Microglobulin. The subclass of the antibody is IgG1. The hybridoma has been cultured and stored under -196 degrees C for more than eight months and its secretion remains stable.

Animals↗