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Biomedical subjects

L Zhou

Publications and source records attributed to L Zhou.

At least 505 records · Page 28Linked to original sources
PubMed1995

An extensive subfrontal approach to the lesions involving the skull base.

A modification of the transbasal approach of Dorome called extensive subfrontal approach and the surgical results with this approach in 22 cases are presented. Bilateral frontal craniotomies incorporated with the removal of orbital ridges and part of the orbital roofs were fashioned en bloc. It may give rise to good exposure of the midline lesions of the anterior, middle and posterior skull base, minimizing the need for the retraction of frontal lobes. There was no surgical mortality in this series of cases. Of the 20 cases with tumors, total resections were achieved in 11 cases, subtotal or large resections in 4 cases and partial resection in one case. Two patients with spontaneous rhinorrhea were successively treated surgically. 21 patients had a follow-up with a time ranging from 1-11 years (a mean of 3 years). 15 patients resumed their jobs with no evidence of recurrence of the original disease, and 5 patients able to live self-care. One patient with an olfactory neuroblastoma died 3 years after the operation owing to relapse of the tumor.

Adolescent↗
PubMed1995

[The posterolateral suboccipital approach to the lesions located at the anterior portion of the craniocervical junction].

A surgical approach to the anterior lower brainstem and upper cervical spinal cord consists of a fashion of unilateral suboccipital scalp flap, exposure and resection of the suboccipital bone and hemilamina of C1, removal of occipital condyle and the lateral mass of C1 (occasionally). The satisfaction of exposing the anterolateral portion of lower brainstem and upper cervical spinal cord can be obtained with minimal retraction of the nervous tissue. 13 patients, 9 with tumors, 2 with giant vertebral aneurysms, 2 with craniocervical malformations, underwent this operative procedure with no surgical mortality and morbidity which related to the approach.

Adult↗
PubMed1995

The Brn-3 family of POU-domain factors: primary structure, binding specificity, and expression in subsets of retinal ganglion cells and somatosensory neurons.

A search for POU domain sequences expressed in the human retina has led to the identification of three closely related genes: Brn-3a, Brn-3b, and Brn-3c. The structure and expression pattern of Brn-3b was reported earlier (Xiang et al., 1993); we report here the structures and expression patterns of Brn-3a and Brn-3c. Antibodies specific for each Brn-3 protein were generated and shown to label only ganglion cells in a variety of vertebrate retinas. A complex pattern of strongly and weakly immunolabeled ganglion cells was observed in mouse, cat, and monkey retinae. In mouse and cat retinae, Brn-3a and Brn-3b proteins are found in a large fraction of ganglion cells, whereas Brn-3c is present in fewer ganglion cells. In the cat retina, anti-Brn-3a immunoreactivity was strong in the small ganglion cells (gamma cells) and weak in the remaining ganglion cells (alpha and beta cells); anti-Brn-3b immunoreactivity was present in all ganglion cells; and anti-Brn3c immunoreactivity was confined to the small ganglion cells. Immunolabeling of macaque retinae following retrograde labeling from the lateral geniculate nucleus revealed strong anti-Brn-3a immunoreactivity in a minority of retrogradely labeled P-type ganglion cells, and weak Brn-3a immunoreactivity in all of the remaining P- and M-type ganglion cells. In the same retinae, strong anti-Brn-3b immunoreactivity was seen in nearly all P-type ganglion cells and weak immunoreactivity in nearly all M-type ganglion cells. Each of the Brn-3-specific antibodies also labeled subsets of neurons in the dorsal root and trigeminal ganglia, suggesting that primary somatosensory neurons and retinal ganglion cells share genetic regulatory hierarchies. In vitro selection of an optimal DNA binding site using the Brn-3b POU domain has revealed a consensus [(A/G)CTCATTAA(T/C)] that is recognized by each of the Brn-3 POU domains and is distinct from binding sites previously described for other POU domain proteins.

Amino Acid Sequence↗
PubMed1995

Supplementary comments on the standardization of auricular points.

This paper is intended to supplement accurate descriptions concerning auricular point location and provide studies in establishing basic landmarks of the auricle. This paper mainly discusses the medial border of helix, antihelix peak, scapha groove, antihelix scapha border, cymba concha border of the antihelix, deltoid fossa border of the antihelix, cymba concha folding line, cymba concha border of the antitragus, upper line of ear lobe, and the anterior border of tragus.

Acupuncture Points↗
PubMed1995

[The disturbance of Ca2+ transport and the changes of some relative factors in arterial smooth muscle cells from spontaneously hypertensive rats with different age].

The purpose of this study was to observe the abnormalities of calcium transport of cultured arterial smooth muscle cells (ASMC) in both prehypertensive and hypertensive SHR and their control WKY rats. The changes in cAMP, ANG II and CaM contents in ASMC were also studied. The results indicated that the Ca2+ influx in ASMC of prehypertensive SHR was increased compared with that of the control, although the value of that in hypertensive SHR was higher significantly more than that of the prehypertensive rat, but there was no significant difference between them. On the other hand, the Ca2+ efflux in ASMC of prehypertensive SHR was decreased compared with that of WKY rats. A more seriously decreased efflux value was found in hypertensive SHR. The cAMP and CaM content were higher than those in WKY rats. In addition, ANG II content in ASMC had a direct bearing on blood pressure, showing a marked difference between prehypertensive and hypertensive SHR. The disturbance of transmembrane Ca2+ transport in ASMC of hypertensive rats appears to be related to genetic defect and the changes of cAMP contents might play a role in membrane Ca2+ transport in ASMC during the development of hypertension. Furthermore the level of arterial ANG II may be related to the elevation of blood pressure in hypertension.

Age Factors↗
PubMed1995

Loss of cell-matrix cohesiveness after phagocytosis by trabecular meshwork cells.

PURPOSE: To investigate the response of trabecular meshwork cells to phagocytic events. METHODS: Cultured bovine trabecular meshwork cells were established and exposed to latex microspheres for 40 to 44 hours. After phagocytosis, the cohesiveness of cells to their underlying matrix was measured by the susceptibility to trypsin, as indicated by the time needed to be liberated from culture plates. The amounts of two cell attachment proteins, fibronectin and laminin, in both the phagocytically challenged and the control cultures were measured at various postphagocytosis time points with an enzyme-linked immunosorbent assay. The fibronectin and laminin network was visualized with immunostaining. The mRNA levels were analyzed by Northern blot. Zymography using gelatin-containing gels was also performed to examine the gelatinase activities. RESULTS: Compared with controls, cells in phagocytically challenged cultures were more sensitive to trypsin. At the 4- and 8-hour postphagocytosis time points, the trypsinization time needed to suspend cells from tissue culture plates was significantly shorter for phagocytically challenged cells. Also, at these two time points, reduced amounts of fibronectin and laminin, as well as disruption of the fibronectin-laminin network, were observed in the phagocytically challenged trabecular meshwork cultures. The mRNA level for fibronectin was reduced, and a slightly increased gelatinase activity was noted. The fibronectin and laminin levels returned to normal by 24 hours. CONCLUSIONS: Results suggest that after phagocytosis, trabecular meshwork cells exhibit a short-term loss in cell-matrix cohesiveness. Such a loss may be related to diminished levels of cell attachment proteins.

Animals↗
PubMed1995

[Effect of wu lin powder and its ingredients on atrial natriuretic factor level in mice].

Wu Lin powder (WLP) is a prescription that causes urination to remove dampness. In order to elucidate its mechanism of action, the effect of WLP on atrial natriuretic factor (ANF) was observed. The results showed that the level of ANF was significantly higher in the plasma of mice after giving WLP as well as giving Alisma orientalis or Cinnamomum cassia orally, compared with control, P < 0.05, 0.01 and 0.001 respectively. The effect was most evident at 45 minute after giving WLP (P < 0.05). It is suggested that ANF might play an important role in therapeutic action of WLP.

Animals↗
PubMed1995

[Endoscopic mucosectomy for resection of early gastric cancer and precancerous lesions].

The authors collected 14 cases of early gastric cancer located in the mucosa and precancerous lesions which were resected with endoscopic mucosectomy. These lesions were as follows: 6 cases were early cancer (IIc type: 4 cases; IIa type: 2 cases); 3 cases were severe dysplasia; 5 cases were adenoma, Yamada I type. The size of all the lesions was less than 20mm. Four cases of early gastric cancer were resected completely. Two cases were resected incompletely, but radical gastrectomy was performed one month after endoscopic mucosectomy. All the three cases of severe dysplasia had complete resection. But two of them received resection twice. Five cases of adenoma were also resected completely. The criteria of complete endoscopic resection were those reported in the Japanese literature. All cases have been followed up for 4-41 months; endoscopic and histological studies showed that there were no residual and recurrent cancer cells. The complete resection rate was 85.7% (12/14). The results suggest that endoscopic mucosectomy can be applied to the patients with early gastric cancer located in the mucosa and precancerous lesions less than 20mm in size, which can be resected completely. This method is safe, entails less complications and is especially suitable for the old and weak patients.

Adenoma↗
PubMed1995

[Effects of the potassium channel activator cromakalim on human isolated bronchial smooth muscle].

The method which can be used to measure human small smooth muscle function in vitro with the bronchiolar strip preparation was described. The aim of the present study was to investigate the effect of cromakalim against histamine acetylcholine, prostaglandin F2 alpha in human isolated bronchiolar smooth muscle. The results showed the order of relaxant potencies was cromakalim > salbutamol > Theophylline. The relaxation responses to cromakalim, salbutamol, theophylline for histamine or prostaglandin F2 alpha were not significantly different. The relaxation responses to cromakalim, salbutamol, theophylline for acetylcholine were significantly different. Cromakalim was more potent and more effective than salbutamol and theophylline. Cromakalim was able to produce an additional relaxation response in the presence of a maximal relaxation induced by salbutamol and theophylline.

Adult↗
PubMed1995

Molecular structure alteration of IgG increased anticomplementary activity of intravenous immunoglobulin.

AIM: To study the cause of anticomplementary activities (ACA) of intravenous immunoglobulins (IVIG). METHODS: ACA were determined by two assays (limit test and 100CH50 test), distributions of IgG molecular size (polymer, dimer, monomer and fragment) by HPLC, IgG subclasses and IgA contents by radial immunodiffusion, prekallikrein activator (PKA) and kallikrein (KK) activities by chromogenic assay, potency of antibody against hepatitis B surface antigen (Anti-HBs) by enzyme-linked immunosorbent assay (ELISA). RESULTS: The two ACA assays showed good correlation. However, ACA levels were not associated with distributions of IgG molecular size, IgG subclasses and IgA contents, PKA and KK activities. After heating incubation, ACA levels increased markedly and Anti-HBs decreased notably, distributions of IgG molecular size remained relatively constant. CONCLUSION: Molecular structure alteration of IgG increased spontaneous complement activation of IVIG.

Complement Activation↗
PubMed1995

[In vitro antibacterial activity of cefoperazone-sulbactam].

This study was conducted to evaluate the antibacterial activity of CPZ-SBT in 1,146 clinical isolates and compared with that of CPZ and other antimicrobial agents. CPZ-SBT has much better antibacterial activity than CPZ against B-lactamase producing organisms. Of the 834 gram negative organisms tested, 165 were CPZ resistant, but 94 (57.0%) of them were still susceptible to CPZ-SBT, CPZ-SBT broadens the antibacterial spectrum of CPZ, it has good activity against Acinetobacter spp and B fragilis. Compared with other antimicrobial agents tested, CPZ-SBT is as active as ceftazidime, amikacin and ciprofloxacin against Enterobacteriaceae, P aeruginosa and Acinetobacter spp, but slightly less active than imipenem. It is as active as imipenem, timentin and metronidazole against B fragilis and other anaerobes. The results show that CPZ-SBT is a new member of the broad spectrum antimicrobial agents. It may become a promising agent for the treatment of severe infections caused by cefoperazone-resistant Gram negative bacilli including P aeruginosa.

Acinetobacter↗
PubMed1995

[An experimental study of the expression and localization of tumor necrosis factor mRNA in liver of rats with severe burn].

In situ hybridization was used to study the expression and localization of tumor necrosis factor (TNF) mRNA in liver of rats after burn. The results showed that the Kupffer cells expressed TNF mRNA in normal rats. After burn, the number of positive expression cells increased quickly, the expression reached max-mum at 6h postburn, and there were no significantly different with normal at 24h postburn. The dynamic changes of number of TNF mRNA producing cells was similar to that of the portal plasma endotoxin level. Kupffer cells located in sinusoid surrounding portal vein expressed TNF mRNA especially at 6h-12h postburn. Also the sinusoid endothlial cells and infiltrative inflammation cells surrounding portal vein were the TNF mRNA-producing cells, this changes appeared significantly at 12-24h postburn. The results suggested that the endotoxin originated from gut may be the principal stimulator for expression of TNF mRNA. The expression of endothlial cells and neutrophils suggested that these cells had been activated. So the endothlium, neutrophils and Kupffer cell play an important role in the pathogenesis of the endotoxin-induced live injury.

Animals↗
PubMed1995

Novel intracellular signaling function of prostaglandin H synthase-1 in NF-kappa B activation.

Many potent nonsteroidal antiinflammatory drugs (NSAIDs) exert their effects by inhibiting the cyclooxygenase activity of prostaglandin H synthase-1 (PGHS1, thus disrupting prostaglandin biosynthesis. However, these drugs do not block the activation of NF-kappa B, an inducible transcription factor which regulates numerous inflammation-related genes. Here we demonstrate that PGHS1 peroxidase, a NSAID-insensitive activity of PGHS1, mediates NF-kappa B activation through an intracellular reactive oxygen signaling pathway. Overexpression of PGHS1 strongly potentiated NF-kappa B activation by phorbol esters and dramatically elevated the generation of intracellular reactive oxygen species (ROS) in response to low concentrations of t-butyl peroxide. Both functions were dependent on PGHS1 peroxidase activity and could be suppressed by the potent antioxidant pyrrolidine dithiocarbamate. In contrast, elimination of PGHS1 cyclooxygenase activity by NSAIDs or site-directed mutagenesis failed to block ROS production or NF-kappa B activation. Thus, PGHS1 peroxidase serves an intracellular signaling function leading to NF-kappa B activation, separable from its role in prostaglandin synthesis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

[Effect of the active components of Ranunculus ternatus Thunb. on the inductive production of tumor necrosis factors by macrophages].

The authors set up a screening system for the detection of TNF inducers. By using this model 36 traditional Chinese medical herbs from 28 families were studied. Seven herbs from 7 families were found to be active in the TNF induction. Among them Ranunculus Ternatus (RT) is the best one. The active components of RT were isolated from the crude extract by solvent extraction and column chromatography. Eleven fractions were obtained. RT-A2, one of the active components, is a white crystal and its IR spectrum is similar to Standard Infrared Grating Spectra No. 28344K. Therefore, RT-A2 may be identified as a fatty acid (palmitic acid). Its optimum dose of inducing TNF is 50 micrograms/ml in vitro. TNF induced in the cell culture was demonstrated by monoclone antibody neutralizing test.

Animals↗
PubMed1994

Correction of lethal intestinal defect in a mouse model of cystic fibrosis by human CFTR.

Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). A potential animal model of CF, the CFTR-/- mouse, has had limited utility because most mice die from intestinal obstruction during the first month of life. Human CFTR (hCFTR) was expressed in CFTR-/- mice under the control of the rat intestinal fatty acid-binding protein gene promoter. The mice survived and showed functional correction of ileal goblet cell and crypt cell hyperplasia and cyclic adenosine monophosphate-stimulated chloride secretion. These results support the concept that transfer of the hCFTR gene may be a useful strategy for correcting physiologic defects in patients with CF.

Animals↗
PubMed1994

Tepoxalin, a novel immunosuppressive agent with a different mechanism of action from cyclosporin A.

Tepoxalin, a compound previously identified as a dual cyclooxygenase/lipoxygenase (CO/LO) inhibitor, is a potent inhibitor of T cell proliferation. Comparing the suppressive effects of tepoxalin and cyclosporin A (CsA) on OKT3-, PMA-, IL-2-, and PMA+ionomycin-induced T cell proliferations revealed marked differences in the mechanism of action between the two compounds. Whereas CsA was most effective in suppressing OKT3-stimulated proliferation, tepoxalin was more potent in inhibiting PMA-, PMA+ionomycin-, and IL-2-induced proliferation. Quantitative PCR (QPCR) assays used to detect cytokine messages showed that tepoxalin blocked IL-2 mRNA transcription in PMA- and PMA+ionomycin-, but not OKT3-stimulated T cells whereas CsA was most potent in inhibiting OKT3-induced IL-2 mRNA induction in these cells. Both tepoxalin and CsA did not inhibit the expression of IL-2R; however, only tepoxalin, but not CsA, inhibited the proliferation of IL-2-dependent blasts and the transcription of IFN-gamma, an IL-2-dependent target gene. Moreover, addition of exogenous IL-2 restored OKT3-induced proliferation to CsA- but not tepoxalin-treated cells. These data suggest that tepoxalin, but not CsA, suppressed T cell proliferation by inhibiting IL-2-induced signal transduction. Consistent with these findings, tepoxalin, unlike CsA, which was most potent when added at the initiation of OKT3 stimulation, was equally active, regardless of whether it was added at the beginning or 48 h after culture initiation. The difference in mechanism of action between tepoxalin and CsA was confirmed further by the synergistic suppressive effects on T cell proliferation upon co-administration of the two compounds.

Base Sequence↗