Increase of islet yields obtained from human pancreas donor following change of pH value in collagenase digestion medium.
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Adult↗
Biomedical subjects
S Lu
Publications and source records attributed to S Lu.
[Clinical observation on vertical transmission of human papillomavirus].
OBJECTIVE: To observe the possibility of maternal-fetal vertical transmission of human papillomavirus (HPV) via amniotic fluid. METHODS: Specimens of cervical secretions from 30 pregnant women were obtained during the third trimester before rupture of membrane, and specimens of pharyngeal secretions of their neonates were obtained 12-48 hours after birth. Amniotic fluids were collected in 13 pregnant women during cesarean section. The presence of HPV types 6, 11, 16, 18, 31, 33, 35, 38 deoxyribonucleic acid were detected by consensus polymerase chain reaction. RESULTS: HPV deoxyribonucleic acid was found in 16 cervical specimens, 14 pharyngeal specimens and in 3 amniotic fluids, the positive rate was 53.3%, 46.7%, 23.1% respectively. The pharyngeal specimen was also HPV positive in one of the three neonates from the amniotic fluid positive mothers. CONCLUSION: The results indicate that HPV can be transmitted in utero through amniotic fluid and cesarean section can not protect the neonates against vertical transmission completely.
Adult↗
[Identifying the existence of cultured human epidermal allografts with PCR techniques].
It is still controversial whether cultured human epidermal allografts can survive long or not because of the lack of convincing evidence to prove it. In this study, three PCR techniques for the individual identification were used to test the existence of cultured allogeneic keratinocytes when it has been transplanted to differents kinds of wounds. With these methods, the donor genetic marks were found in 27 biopsies of 16 patients who had cultured epidermal cells allografted. The longest biopsy time was 92 days after grafting. The results strongly indicated that the survival time of cultured epidermal allografts was prolonged. The advantage and disadvantage of using the PCR techniques were discussed and the fate of the cultured epidermal allografts could be determined if these techniques are used properly.
Adolescent↗
[Construction and expression of the gene CD4V1V2-PE40, coding for a molecular targeted protein against AIDS].
We here replaced the cell-binding domain in Pseudomonas exotoxin A (PE) with HIV-binding portion of CD4V1V2 molecule and constructed a chimeric gene CD4V1V2-PE40, which can be expressed in E. coli. The hybrid protein displays targeting toxicity toward cells infected by HIV and thus represents a promising novel therapeutic agent for the treatment of AIDS.
ADP Ribose Transferases↗
[Laryngeal paralysis and laryngospasm].
The intrinsic laryngeal muscle potential was recorded with electromyography. Vocal cord movements were observed by a video stroboscope. Laryngeal paralysis is divided into mild, moderate, and severe degrees based on the potentials of intrinsic laryngeal muscles and on the status of vocal cord movements. In the past 11 years (from 1983 to 1993) 1211 cases were diagnosed as having mild, moderate, and severe laryngeal paralysis. Among them, there were 11 cases with laryngospasm including 3 mild, 2 moderate, and 6 severe cases. The findings obtained from careful observation on these 11 cases of laryngospasm demonstrated that there were certain relationships between laryngeal paralysis and laryngospasm. During the course of exacerbation or restoration of paralysis, the laryngospasm may occur.
Adult↗
Cloning and expression of the gene coding for IL-2(60)-PE40, a molecular targeted protein.
It has recently been shown that chimeric toxin composed of IL2 fused tp PE40, a mutant form of Pseudomonas Exotoxin A devoid of its native cell recognition and binding domain was cytotoxic to IL2 receptor bearing cells. We here amplified the gene IL-2 (60), which codes for the N-terminal 1-60 amino acids of human IL-2 by PCR. After that, we fused it to PE40 and the new chimeric protein IL-2(60)-PE40 was expressed in E. coli. SDS-PAGE revealed that IL-2(60)-PE40 chimeric protein accounts for more than 18% of total cell proteins. As the region IL-2 binds with its receptor was defined in the N-terminal residues 8-54 of IL-2, such fusion proteins will have the same activity with IL-2-PE40. Following primary purification, IL-2(60)-PE40 was shown to be very toxic to IL-2 receptor-positive cells but non measurable effect on the cells lacking IL-2 receptors. Such a structure has not been reported by now. The fusion protein is useful for suppressing the immune response in cases of rejection of allografts and organ transplants and as therapeutic agents for the treatment of IL-2 receptor related diseases such as autoimmune disease, ATL (adult T-cell leukemia), et al.
Animals↗
[Experimental studies of the effects of prestress on intact canine bone structure].
Three types of plate made of 316L medical stainless steel were applied in the experiment. They were divided into conventional plate, concave plate, sliding plate by their different shapes and functions. They were fixed on intact canine tibias and compared with intact canine tibias that were only fixed with conventional screws. Stress values were measured with static strain instrument in different conditions and in vitro tissue that was poured with disulphine blue. CT scanning was done in different stages. The experiment results proved that different extents of intraosseous prestress were reduced by different plate fixings. The conventional plate group with high stiffness produced the greater prestress and stress shielding value and slight circulation disorder in bone tissue in early stage, but the osteoporosity of tibias bone ocurred early (1 month); conventional plate with low stiffness produced the less prestress and stress shielding value and severe circulation disorder in bone in early stage, but the osteoporosity ocurred late (3 month). We consider the cause of local osteoporosity of tibias bone after plate fixed were mainly prestress, and stress shielding is secondary in early stage (3 month). The local circulation is disorder is not important factor.
Animals↗
[Detection of human papilloma virus in esophageal squamous cell carcinoma and adjacent tissue specimens in Linxian].
A total of 87 human esophageal tissue specimens, comprising 35 squamous cell carcinomas and 52 adjacent tissue specimens (with no gross evidence of tumors) were obtained from patients who underwent surgery for cancer of the esophagus in Lin-xian county, Henen Province. The tissue specimens were analyzed for the presence of HPV DNA by Southern blot assay with HPV type 16 and 18 probes and by polymerase chain reaction (PCR) with HPV consensus primer. The esophageal epithelial specimens of human fetus, and condyloma tissue contained HPV type 6 were used as controls. The results showed that no HPV 16, 18 and other type were detectable in any case, either in the esophageal carcinomas or adjacent tissue specimens. Thus, the role of HPV in the carcinogenesis of esophagus remains unclear. The high incidence of esophageal squamous cell carcinoma in Lin-xian is probably related to other factors such as N-nitrosamines.
Base Sequence↗
[Correlation between p53 nuclear protein accumulation and mutations of the p53 gene in human esophageal cancer from linxian].
Thirty-three esophageal tumors were analyzed by immunohistochemistry for P53 nuclear protein accumulation, and the results were compared to p53 gene mutations by PCR-direct sequence analysis. A highly significant correlation between the presence of p53 mutations and p53 nuclear protein accumulation was found. Of 33 tumors, 23 (69.7%) that demonstrated P53 protein expression 12(36%) had p53 mutations. Of 12 tumors with p53 mutations, 9 tumors showed P53 intensive nuclear reactivity. The results reported here are consistent with the idea that p53 mutations may be an important biological event in esophageal cancer progression and P53 expression was correlated with p53 gene mutation.
Adenocarcinoma↗
[Cloning and sequencing of the gene PE40, coding for a portion of Pseudomonas exotoxin A].
Gene PE40 coding for a mutant form of Pseudomonas Exotoxin A was devoid of its native cell binding domain, and was amplified from the total DNA of P. aeruginosa PA103 by PCR. After being sequenced, it was cloned into expressional vector pBV220 to get a recombinant plasmid, which will be useful in the research of molecular targeted protein.
ADP Ribose Transferases↗
[Confirmation of the persistence of cultured allogeneic keratinocytes by DNA fingerprints].
We have successfully used DNA fingerprint to confirm the existence of cultured allogeneic keratinocytes after transplantation. Four biopsies from two burn patients who had been grafted with cultured allogeneic keratinocytes were examined by this technique. The results showed that the cultured allogeneic keratinocytes could survive on the grafted wounds for at least 28 days post grafting.
Adult↗
[The effect of intra-aortic balloon pumping in case of left main coronary artery stenosis].
In order to improve perfusion of coronary artery in case of coronary artery stenosis, effect of intra-aortic balloon pumping (IABP) on coronary blood flow (CBF) was investigated. To this end hemodynamic parameters of heart functions with and without stenosis were analysed under IABP. Hemodynamic effect of IABP was obviously influenced by the coronary artery stenosis.
Animals↗
Tagged mutations at the Tox1 locus of Cochliobolus heterostrophus by restriction enzyme-mediated integration.
We have used the restriction enzyme-mediated integration insertional mutagenesis procedure to tag the Tox1 locus in the filamentous Ascomycete Cochliobolus heterostrophus. Mutations at other, unselected, loci were also identified and a high proportion (30-50%) of them were tagged. This procedure may be of general utility for simultaneously mutating and tagging genes in fungi and in other eukaryotes. The Tox1 locus of C. heterostrophus has been defined by Mendelian analysis as a single genetic element that controls production of T toxin, a linear polyketide involved in virulence of the fungus to its host plant, corn. To tag Tox1, protoplasts of a Tox1+ (T-toxin producing) strain were transformed with a linearized, nonhomologous plasmid along with an excess of the restriction enzyme used to linearize the plasmid. Of 1310 transformants recovered, two produced no detectable T toxin in culture or on corn plants. In each of these transformants, the Tox- mutation mapped at Tox1, was tagged with the selectable marker (hygB) on the transforming plasmid, and was tightly linked to the other tagged Tox- mutation. The two mutations, however, represent two different points of plasmid insertion at the Tox1 locus.
Ascomycota↗
Identification of chemoattractant receptors and G-proteins in the vomeronasal system of garter snakes.
Garter snakes respond to purified chemoattractants derived from prey. The specific binding sites for one of these chemoattractants, ES20, in the vomeronasal organ was saturable and reversible. Binding sites for ES20 were abolished by heating or greatly reduced by Pronase digestion. ES20 chemoattractant activity and receptor binding required Ca2+. Binding of ES20 to sensory epithelium derived from animals with bipolar neurons depleted by denervation was reduced 22-43% as compared to control animals. However, there was an upregulation of the ES20 receptor population in the nonsensory cells following nerve cuts. Three G-proteins (Gs, Gi, and G(o)) were tentatively identified using immunoreactivity and ADP-ribosylation techniques. Gi and G(o) proteins were shown to be coupled with ES20-receptor and effectors as evidenced by: 1) the affinity of ES20-receptor was decreased by GTP gamma S; 2) ES20-receptor binding caused a reduction in ADP-ribosylation of pertussis toxin-susceptible G-proteins, and the inhibitory effect of ES20-receptor on ADP-ribosylation was attenuated by GDP beta S; 3) the effect of ES20-receptor on ADP-ribosylation of the pertussis toxin-susceptible G-proteins could be mimicked by G-protein activators, such as GTP gamma S or AlF3; 4) ES20-receptor binding resulted in a decrease of the basal level of cAMP; 5) the binding of ES20 to its receptors caused an increase in the level of D-myo-inositol 1,4,5-trisphosphate.
1-Methyl-3-isobutylxanthine↗
Mouse homeobox gene Dbx: sequence, gene structure and expression pattern during mid-gestation.
Homeobox genes regulate multiple aspects of mouse development including the axial patterning in the central nervous system. Some of the more divergent members of this gene family are expressed in the anterior region of the central nervous system where the Hox genes are not expressed. We previously reported the isolation of a mouse homeobox gene, Dbx, from the forebrain. Here we describe its genomic structure, complete cDNA sequence, characterization of the basal promoter and the expression pattern at different stages of the developing embryo. During early and mid-gestation, Dbx expression is restricted to the telencephalon, diencephalon, dorsal mesencephalon and spinal cord. At later gestational stages, Dbx expression continues in the dorsal mesencephalon and diencephalon, in which expression is more restricted than at the earlier stages. Dbx transcripts were also detected in the primitive cerebellum. At all stages, the Dbx expressing regions contain a high proportion of proliferating cells, suggesting a role for Dbx in patterning the central nervous system during embryogenesis.
Amino Acid Sequence↗
Overproducing the Bacillus subtilis mother cell sigma factor precursor, Pro-sigma K, uncouples sigma K-dependent gene expression from dependence on intercompartmental communication.
During sporulation of Bacillus subtilis, proteolytic activation of pro-sigma K and ensuing sigma K-dependent gene expression normally require the activity of many sporulation gene products. We report here that overproducing pro-sigma K at the onset of sporulation substantially uncouples sigma K-dependent gene expression from its normal dependency. Overproducing pro-sigma K in strains with a mutation in spoIIIG, spoIIIA, spoIIIE, or spoIVB partially restored sigma K-dependent gene expression in the mother cell and resulted in accumulation of a small amount of polypeptide that comigrated with sigma K, but these mutants still failed to form spores. In contrast, sporulation of spoIVF mutants was greatly enhanced by pro-sigma K overproduction. The products of the spoIVF operon are made in the mother cell and normally govern pro-sigma K processing, but overproduction of pro-sigma K appears to allow accumulation of a small amount of sigma K, which is sufficient to partially restore mother cell gene expression and spore formation. This spoIVF-independent mechanism for processing pro-sigma K depends on sigma E, an earlier-acting mother cell-specific sigma factor. The spoIIID gene, which encodes a mother cell-specific DNA-binding protein that is normally required for pro-sigma K production, was shown to be required for efficient pro-sigma K processing as well. bof (bypass of forespore) mutations bypassed this requirement for spoIIID, suggesting that SpoIIID is less directly involved in pro-sigma K processing than are spoIVF gene products. However, bof spoIIID double mutants overproducing pro-sigma K still failed to sporulate, indicating that SpoIIID serves another essential role(s) in sporulation in addition to its multiple roles in the production of sigma K.
Bacillus subtilis↗
Effect of chronic renal medullary nitric oxide inhibition on blood pressure.
The effects of chronic nitric oxide inhibition in the renal medulla on renal cortical and medullary blood flow, sodium balance, and blood pressure were evaluated in conscious uninephrectomized Sprague-Dawley rats. During a 5-day renal medullary interstitial infusion of the nitric oxide inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 120 micrograms/h) in saline (0.5 ml/min), renal medullary blood flow was selectively decreased by 30% after 2 h and was maintained at that level for the entire infusion. The decrease in medullary blood flow was associated with sodium retention and increased blood pressure. After the cessation of L-NAME infusion, medullary blood flow returned to control, and the sodium balance became negative as blood pressure returned to baseline. These data indicate that renal medullary nitric oxide plays an important role in the regulation of renal blood flow, sodium excretion, and blood pressure.
Animals↗
Renal medullary captopril delivery lowers blood pressure in spontaneously hypertensive rats.
We examined the contribution of renal medullary function to the maintenance of hypertension in spontaneously hypertensive rats by infusing captopril chronically into the renal medullary interstitial space of uninephrectomized rats. Changes in cortical and medullary blood flow were determined using a newly developed optical fiber implantation technique for laser-Doppler flowmetry. Renal medullary interstitial infusion of captopril (5 mg/kg per day) selectively increased medullary blood flow by 40% without altering renal cortical blood flow throughout the 5 days of captopril delivery. In association with the selective increase of medullary perfusion, a significant natriuresis was observed on the second day of the drug infusion, and urine osmolality was significantly reduced during the first 3 days of captopril infusion. Mean arterial pressure was significantly decreased by 20 mm Hg during 5 days of captopril infusion, and the chronic renal function curve was shifted to a lower level of arterial pressure compared with the control values when 0.9% sodium chloride saline vehicle was infused. Intravenously infused captopril at 5 mg/kg per day did not alter mean arterial pressure, excluding the possibility that the hypotensive effect of medullary captopril infusion was due to recirculation. In summary, chronic reduction of the elevated renal medullary vascular tone by medullary interstitial infusion of captopril reset the steady-state renal function curve and lowered arterial pressure in spontaneously hypertensive rats.
Animals↗