Biomedical subjects

F Gong

Publications and source records attributed to F Gong.

At least 19 recordsLinked to original sources

PubMed2000

The genome sequence of Drosophila melanogaster.

The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. We have determined the nucleotide sequence of nearly all of the approximately 120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy supported by extensive clone-based sequence and a high-quality bacterial artificial chromosome physical map. Efforts are under way to close the remaining gaps; however, the sequence is of sufficient accuracy and contiguity to be declared substantially complete and to support an initial analysis of genome structure and preliminary gene annotation and interpretation. The genome encodes approximately 13,600 genes, somewhat fewer than the smaller Caenorhabditis elegans genome, but with comparable functional diversity.

Animals↗

PubMed2000

Comparative genomics of the eukaryotes.

A comparative analysis of the genomes of Drosophila melanogaster, Caenorhabditis elegans, and Saccharomyces cerevisiae-and the proteins they are predicted to encode-was undertaken in the context of cellular, developmental, and evolutionary processes. The nonredundant protein sets of flies and worms are similar in size and are only twice that of yeast, but different gene families are expanded in each genome, and the multidomain proteins and signaling pathways of the fly and worm are far more complex than those of yeast. The fly has orthologs to 177 of the 289 human disease genes examined and provides the foundation for rapid analysis of some of the basic processes involved in human disease.

Animals↗

PubMed2000

Inhalation of nebulized nitroglycerin in dogs with experimental pulmonary hypertension induced by U46619.

BACKGROUND: Pulmonary hypertension (PH) causes mortality in some congenital and acquired heart and lung diseases. However, inhalation of NO gas requires complicated and expensive instruments and elaborate preparations to avoid toxic gas administration. We tested the effectiveness and safety of inhaled nebulized nitroglycerin (Neb-NTG) in dogs with experimental PH. METHODS: Experimental PH was induced by continuous infusion of a thromboxane analog (U46619). The U46619 infusion rate was adjusted to maintain a systolic pulmonary artery pressure (PAP) at 40 mmHg in 10 anesthetized and mechanically ventilated dogs. Then, 20 micrograms/kg of NTG liquid nebulized by compressed air was inhaled. RESULTS: After infusion of U46619, the systolic, diastolic and mean PAP increased by 119%, 228% and 169%, respectively, and the systolic, diastolic and mean systemic arterial pressures (SAP) increased by 19%, 29% and 23%, respectively. The systolic pulmonary to systemic pressure ratio (Pp/Ps) and mean Pp/Ps increased by 83% and 113%, respectively, and the pulmonary vascular resistance (PVR), systemic vascular resistance (SVR) and pulmonary to systemic resistance ratio (Rp/Rs) increased by 341%, 100% and 145%, respectively. After inhalation of Neb-NTG in dogs with experimental PH, systolic, diastolic and mean PAP and PVR decreased by 25 +/- 4, 26 +/- 11, 25 +/- 9 and 31 +/- 21%, respectively. There were no significant changes in systolic, diastolic and mean SAP, SVR, cardiac output and plasma methemoglobin concentrations. The systolic and mean Pp/Ps decreased by 18 +/- 7 and 20 +/- 7%, respectively. The Rp/Rs decreased by 25 +/- 13%. CONCLUSIONS: The results of this study demonstrate that Neb-NTG is an effective and selective pulmonary vasodilator and may offer a new therapeutic option for PH.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed2000

Wireless endoscopy.

BACKGROUND: Miniaturization of electronic components may allow the construction of new types of endoscopes that no longer require external wires, cables, or optical fibers. Our aim was to assess the feasibility of wireless endoscopy and to construct experimental prototypes using miniature charge-coupled device cameras, light sources, microwave transmitters, and batteries. METHODS: Feasibility, dimensions of miniature components, and power requirements were assessed. Prototypes were constructed and tested using cameras, transmitters, and halogen lamps powered by small batteries; 10.6 and 0.187 GHz transmitters were used to transmit the video signal. RESULTS: Moving television images were transmitted through models, post-mortem and live porcine stomachs, to the external receiver. Transmission of images through the abdomen was tested by placing the device in a microwave-impermeable box behind a volunteer's back and the receiver in front of his abdomen. In other experiments the endoscope was used inside the human mouth. The device was placed surgically in the stomachs of 150 kg pigs in vivo and good-quality color television image reception was achieved. CONCLUSIONS: These experiments demonstrate the feasibility of constructing a new type of endoscope that can transmit moving color television images from the GI tract without requiring fiberoptic or electrical cables.

Animals↗

PubMed1999

An ambulant porcine model of acid reflux used to evaluate endoscopic gastroplasty.

BACKGROUND: There is a lack of suitable models for testing of therapeutic procedures for gastro-oesophageal reflux disease. Endoscopic sewing methods might allow the development of a new less invasive surgical approach to treatment of gastrointestinal disorders. AIMS: To develop an animal model of gastro-oesophageal reflux for testing the efficacy of a new antireflux procedure, endoscopic gastroplasty, performed at flexible endoscopy without laparotomy or laparoscopy. METHODS: At endoscopy a pH sensitive radiotelemetry capsule was sewn to the oesophageal wall, 5 cm above the lower oesophageal sphincter, in six large white pigs. Ambulant pH recordings (48-96 hours; total 447 hours) were obtained. The median distal oesophageal pH was 6.8 (range 6.4-7.3); pH was less than 4 for 9.3% of the time. After one week, endoscopic gastroplasty was performed by placing sutures below the gastro-oesophageal junction, forming a neo-oesophagus of 1-2 cm in length. Postoperative manometry and pH recordings (24-96 hours; total 344 hours) were carried out. RESULTS: Following gastroplasty, the median sphincter pressure increased significantly from 3 to 6 mm Hg and in length from 3 to 3.75 cm. The median time pH was less than 4 decreased significantly from 9.3% to 0.2%. CONCLUSIONS: These are the first long term measurements of oesophageal pH in ambulant pigs. The finding of spontaneous reflux suggested a model for studying treatments of reflux. Endoscopic gastroplasty increased sphincter pressure and length and decreased acid reflux.

Animals↗

PubMed1999

[An investigation of the polymorphism of HLA class II alleles in the Han population in Hubei Province of China].

OBJECTIVE: To investigate the polymorphism of HLA class II alleles in the Han population in Hubei province. METHODS: The alleles of DRB1*(n=168), DQB1*(n=160) and DPB1*(n=93) were typed by using the polymerase chain reaction/sequence specific primer(PCR/SSP) and polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) techniques. RESULTS: 39 HLA-DRB1, 15 DQB1 and 17 DPB1 alleles were found. Alleles with higher frequencies are DRB1*0901 (GF=14%), *1501(GF=11.3%), *0301(GF=7.1%), *0803(GF=4.8%); DQB1*0301(GF=18.8%), *0303(GF=18.4%), *0201(GF=10%), *0302(GF=8.4%); DPB1*0501(GF=31.2%), *0401(GF=15.1%), *0201(GF=14%), *0402(GF=11.8%), respectively. As compared with Caucasians, the Han people in Hubei province have higher gene frequencies of DRB1*0901, *1001, *0803; DQB1*0303, *0502 and DPB1*0501, *0202; and lower gene frequencies of DRB1*0301, *0401, *1301; DQB1*0201, *0603 and DPB1*0401, suggesting that Hubei Hans have their own layout of HLA class II allele frequencies. CONCLUSION: These data may serve as normal reference values for the Han population in south China.

Alleles↗

PubMed1998

A randomised controlled comparison of injection, thermal, and mechanical endoscopic methods of haemostasis on mesenteric vessels.

BACKGROUND AND AIMS: A randomised controlled comparison of haemostatic efficacy of mechanical, injection, and thermal methods of haemostasis was undertaken using canine mesenteric vessels to test the hypothesis that mechanical methods of haemostasis are more effective in controlling haemorrhage than injection or thermal methods. The diameter of arteries in human bleeding ulcers measures up to 3.45 mm; mesenteric vessels up to 5 mm were therefore studied. METHODS: Mesenteric vessels were randomised to treatment with injection sclerotherapy (adrenaline and ethanolamine), bipolar diathermy, or mechanical methods (band, clips, sewing machine, endoloops). The vessels were severed and haemostasis recorded. RESULTS: Injection sclerotherapy and clips failed to stop bleeding from vessels of 1 mm (n = 20) and 2 mm (n = 20). Bipolar diathermy was effective on 8/10 vessels of 2 mm but failed on 3 mm vessels (n = 5). Unstretched elastic bands succeeded on 13/15 vessels of 2 mm but on only 3/10 vessels of 3 mm. The sewing machine achieved haemostasis on 8/10 vessels of 4 mm but failed on 5 mm vessels (n = 5); endoloops were effective on all 5 mm vessels (n = 5). CONCLUSIONS: Only mechanical methods were effective on vessels greater than 2 mm in diameter. Some mechanical methods (banding and clips) were less effective than expected and need modification. Thermal and (effective) mechanical methods were significantly (p < 0.01) more effective than injection sclerotherapy. The most effective mechanical methods were significantly more effective (p < 0.01) than thermal or injection on vessels greater than 2 mm.

Animals↗

PubMed1997

N-acyl-homoserine lactone-mediated regulation of phenazine gene expression by Pseudomonas aureofaciens 30-84 in the wheat rhizosphere.

Pseudomonas aureofaciens 30-84 is a soilborne bacterium that colonizes the wheat rhizosphere. This strain produces three phenazine antibiotics which suppress take-all disease of wheat by inhibition of the causative agent Gaeumannomyces graminis var. tritici. Phenazines also enhance survival of 30-84 within the wheat rhizosphere in competition with other organisms. Expression of the phenazine biosynthetic operon is controlled by the phzR/phzI N-acyl-homoserine lactone (AHL) response system (L. S. Pierson III et al., J. Bacterial 176:3966-3974, 1994; D. W. Wood and L. S. Pierson III, Gene 168:49-53, 1996). By using high-pressure liquid chromatography coupled with high-resolution mass spectrometry, the AHL produced by PhzI has now been identified as N-hexanoyl-homoserine lactone (HHL). In addition, the ability of HHL to serve as an interpopulation signal molecule in the wheat rhizosphere has been examined by using isogenic reporter strains. Disruption of phzI reduced expression of the phenazine biosynthetic operon 1,000-fold in the wheat rhizosphere. Coinoculation of an isogenic strain which produced the endogenous HHL signal restored phenazine gene expression in the phzI mutant to wild-type levels in situ. These results demonstrate that HHL is required for phenazine expression in situ and is an effective interpopulation signal molecule in the wheat rhizosphere.

4-Butyrolactone↗

PubMed1997

[Observation on the changes of lipid peroxidation in neonates with sclerema].

Thirty-six hospitalized newborn infants with sclerema (case group), which were divided into mild group(n = 18) and severe group(n = 18), and 28 normal neonates (normal control group) were selected to measure the changes of blood lipid peroxidation (LPO) and superoxide dismutase(SOD) so as to study the role of free radicals and lipid peroxide injury the pathogenesis of the entity. The results showed that the plasma LPO contents were significantly increased and SOD were significantly decreased in the case group when compared with those in the normal group (P < 0.01). The plasma LPO was significantly higher and SOD activity was significantly lower in the severe group than those in the mild group (P < 0.01). The study indicates that the free radicals produced in sclerema neonatorum are great in amount and suggests that free radicals possibly participate in the pathogenesis of the disease.

Erythrocytes↗

PubMed1996

Cutting thread at flexible endoscopy.

BACKGROUND: New thread-cutting techniques were developed for use at flexible endoscopy. A guillotine was designed to follow and cut thread at the endoscope tip. A new method was developed for guiding suture cutters. Efficacy of Nd: YAG laser cutting of threads was studied. Experimental and clinical experience with thread-cutting methods is presented. METHODS: A 2.4 mm diameter flexible thread-cutting guillotine was constructed featuring two lateral holes with sharp edges through which sutures to be cut are passed. Standard suture cutters were guided by backloading thread through the cutters extracorporeally. A snare cutter was constructed to retrieve objects sewn to tissue. Efficacy and speed of Nd: YAG laser in cutting twelve different threads were studied. RESULTS: The guillotine cut thread faster (p < 0.05) than standard suture cutters. Backloading thread shortened time taken to cut thread (p < 0.001) compared with free-hand cutting. Nd: YAG laser was ineffective in cutting uncolored threads and slower than mechanical cutters. Results of thread cutting in clinical studies using sewing machine (n = 77 cutting episodes in 21 patients), in-vivo experiments (n = 156), and postsurgical cases (n = 15 over 15 years) are presented. CONCLUSIONS: New thread-cutting methods are described and their efficacy demonstrated in experimental and clinical studies.

Animals↗

PubMed1996

Antireflux operations at flexible endoscopy using endoluminal stitching techniques: an experimental study.

BACKGROUND: Three antireflux operations-gastroplasty, fundoplication, and anterior gastropexy-were developed for performance at flexible endoscopy without laparotomy or laparoscopy. METHODS: An endoscopic sewing machine mounted on a standard gastroscope, endoscopic knotting devices, overtube, and nylon thread were used to perform these operations in adult beagle dogs. RESULTS: Gastroplasty (n = 10) was accomplished by suturing the anterior and posterior wall of the stomach to create a gastric tube (neoesophagus) along the lesser curve. An anatomic arrangement similar to fundoplication (n = 6) was achieved by invaginating the esophagus and fixing it to the stomach 2 cm distal to the cardioesophageal junction. Anterior gastropexy (n = 6) was performed using a technique similar to that used in creating percutaneous gastrostomies. There was no mortality. Ninety percent of sutures were seen at repeat endoscopy at 4 to 8 week intervals. The gastroplasty group was selected for more extensive evaluation. Manometry using a three-channel perfused catheter system before and after the procedures showed an increase in the lower esophageal sphincter pressure (preoperative median 4.6 mm Hg; post-operative median 13.33 mm Hg, p = 0.008) and cardiac yield pressures (preoperative median 10 mm Hg; postoperative median 19 mm Hg, p = 0.007). CONCLUSIONS: This study demonstrates the feasibility of performing antireflux operations at flexible endoscopy, without laparoscopy or laparotomy, by use of endoluminal suturing techniques.

Animals↗

PubMed1996

Percutaneous transluminal balloon pulmonary valvuloplasty using domestic balloon catheter for congenital pulmonary valve stenosis in children.

OBJECTIVE: To estimate the effect of percutaneous balloon pulmonary valvuloplasty (PBPV) using domestic balloon catheter for congenital pulmonary valve stenosis (PVS) in infants and children. PATIENTS AND METHODS: The data of 70 patients aged from 1.5 to 12 years (mean 5.5 +/- 3.4 years) who underwent PBPV using domestic balloon catheter for PVS in our institution were reviewed. Sixty-six patients had dome-shaped valve stenosis, and 4 had displastic valve stenosis. SaO2 reduced in 5 patients and associated open foramen ovale was noted in 23. Predilatation, right ventricular systolic pressure ranged from 60 to 234 mmHg (mean 115.75 +/- 36.15 mmHg). The systolic gradient (delta P) from right ventricle to pulmonary artery was 89.92 +/- 38.25 mmHg. Balloon diameter was selected 120%-142% of pulmonary valve annulus diameter (mean 132%). All patients were followed up for 3 months-4 years by means of clinical examination. ECG, 2D-UCG, and Doppler-UCG. RESULTS: After dilatation, delta P reduced from 89.92 +/- 38.25 to 14.65 +/- 11.40 mmHg (P < 0.001). The rate of decrease in transvalve gradient (delta P) was 83.7%. No patients experienced procedure-related events. Mid-term follow-up showed that no patients had clinical and instrumental complications. Doppler and ECG analyses showed that delta P did not change significantly similar to immediate gradient after PBPV and right ventricular hypertrophy disappeared progressively 6 months after PBPV. CONCLUSIONS: PBPV is a useful, safe and definitive procedure in the treatment of isolated PVS in infants and children. The properties and features of the balloon catheter produced by Shanghai Med-Tech Factory are similar to those of Med-Tech balloon catheter of U.S.A.

Catheterization↗

PubMed1995

Molecular analysis of genes encoding phenazine biosynthesis in the biological control bacterium. Pseudomonas aureofaciens 30-84.

The DNA sequence of five contiguous open reading frames encoding enzymes for phenazine biosynthesis in the biological control bacterium. Pseudomonas aureofaciens 30-84 was determined. These open reading frames were named phzF, phzA, phzB, phzC and phzD. Protein PhzF is similar to 3-deoxy-D-arabino-heptulosonate-7-phosphate synthases of solanaceous plants. PhzA is similar to 2,3-dihydro-2,3-dihydroxybenzoate synthase (EntB) of Escherichia coli. PhzB shares similarity with both subunits of anthranilate synthase and the phzB open reading frame complemented an E. coli trpE mutant deficient in anthranilate synthase activity. Although phzC shares little similarity to known genes, its product is responsible for the conversion of phenazine-I-carboxylic acid to 2-hydroxy-phenazine-I-carboxylic acid. PhzD is similar to pyridoxamine phosphate oxidases. These results indicate that phenazine biosynthesis in P. aureofaciens shares similarities with the shikimic acid, enterochelin, and tryptophan biosynthetic pathways.

Amino Acid Sequence↗

PubMed1993

Thrombin and bradykinin initiate discrete endothelial solute permeability mechanisms.

This study documents the discrete solute permeability mechanisms associated with physiologically high concentrations of human alpha-thrombin and bradykinin stimulation of bovine pulmonary artery endothelial cell (BPAEC) monolayers using fluorescein isothiocyanate-hydroxyethyl starch macromolecules. Agonist-induced alterations of intracellular free calcium ([Ca2+]i) using fura-2 acetoxymethyl ester were also measured. BPAEC monolayers showed restricted diffusion consistent with a small-pore (approximately 150 A) radius under baseline conditions. Thrombin produced a major increase in monolayer permeability that was greatest for solute molecular radii (ae) > 100 A. This effect was associated with the exposure of the large (approximately 2,000 A) pores of the filter support by 50- to 1,050-microns2 open areas between approximately 0.5% of the adjacent endothelial cells. This heterogeneous endothelial barrier of parallel large- and small-pore transport pathways permitted solute convection with free diffusion across a few large pores to dominate the restricted diffusion of most apparently unperturbed endothelial junctions. Bradykinin produced a small, transient elevation in monolayer permeability to ae < 35 A, consistent with an increase in the number of small pores or a decrease in path length of this transport pathway. The bradykinin- and thrombin-induced peak elevations in [Ca2+]i were inversely associated with the degree of increased monolayer solute permeability, and enzymatically inhibited thrombin produced none of these effects. These data show that bradykinin and human alpha-thrombin represent two distinct classes of endothelial cell agonists that initiate discrete solute permeability mechanisms.

Animals↗

PubMed1992

Restricted diffusion of macromolecules by endothelial monolayers and small-pore filters.

We studied the size-selective permeability and restricted diffusion (Rd) properties of macromolecules across bovine pulmonary artery endothelial cell (BPAEC) or epithelial (LLC-PK1) monolayers grown on polycarbonate (PC) filter supports using fluorescein isothiocyanate-hydroxyethyl starch (FITC-HES, 16 A less than ae less than 180 A). Most BPAEC seeded at subconfluent density and grown for 3-6 days produced barriers with marked Rd. This characteristic was similar to that measured across PC filters with pore radii (rp) of 150 and 250 A without cells. Rd of LLC-PK1 monolayers was consistent with a transport pathway rp of much less than 75A. BPAEC monolayers prepared by supraconfluent seeding showed convective solute transport due to a significant number of incompletely formed intracellular junctions. Most monolayers grown to confluence, or a thin layer of collagen type I prevented this effect, Rd was enhanced when BPAEC monolalyers were grown on this collagen network. These data suggest that the subendothelial layers, which includes basal lamina, pericyte, and interstitial collagen, may act as series resistors with the endothelium to provide the Rd observed in the microvascular wall in vivo. This may explain why BPAEC monolayers grown to confluence without subendothelial layers in vitro showed Rd consistent with large (150-250 A) rp that was significantly greater than those modeled as the small (approximately 50 A) "pore" or 6-A fiber matrix of the in vivo capillary wall.

Animals↗

PubMedDate not supplied

Pichinde virus-induced respiratory failure due to obstruction of the small airways: structure and function.

Respiratory distress that leads to death is seen in patients with Lassa fever. The development of this respiratory problem was studied using a Pichinde virus model (10(4) plaque forming units, IP, survival time 20 +/- 1 days) in strain 13 guinea pigs (n = 35, 229-353 g) of this lethal human contagious infectious disease. Extravascular lung water to bloodless dry lung weight (EVLW/BDLW) ratio showed a modest yet significant increase in animals 13 and 18-21 days postinoculation (PI). In contrast, residual lung blood and lung radioactive 125I-labeled human serum albumin activity index were elevated only in the 18- to 21-day group. These data are consistent with the progressive severity of perivascular edema, lymphocytic pneumonitis, and some alveolar protein between days 13 and 18-21 PI. Lymphocytic pneumonitis appeared to be distributed near most airways and was proportional to the degree of Pichinde virus antigen staining of alveolar macrophages, large mononuclear cells within the pulmonary vascular and extravascular spaces, and alveolar-capillary membranes. These findings suggest that lymphocyte recruitment to the lung reflects the Pichinde virus-induced cell-mediated immune response. Obstructed small bronchi with some lumenal cell debris and hypertrophied epithelial cells were found associated with the areas of marked pneumonitis. The severe hypoxemia and modest anaerobic metabolism in association with marked tachypnea and normocapnia are consistent with small airway obstruction and wasted ventilation, since no change in arterial blood pressure, heart rate, hematocrit, hemoglobin, or blood volume was noted. These data suggest that Pichinde virus-induced respiratory failure was due to obstruction of the small airways with wasted ventilation in association with lymphocytic pneumonitis.

Airway Obstruction↗

PubMedDate not supplied

Nebulized nitroglycerin in children with pulmonary hypertension secondary to congenital heart disease.

Pulmonary hypertension continues to be a major cause of morbidity and mortality, despite new treatments. Since inhaled nitric oxide has been reported to be effective in some cases, we investigated using nebulized nitroglycerine to treat pulmonary hypertension in children with congenital heart disease. Four children (ages 6-72 months) with severe pulmonary hypertension secondary to congenital heart disease (all with membranous ventricular septal defect, undergoing cardiac catheterization) were given 3 cc of nebulized normal saline over 10 min as placebo control, followed by nebulized nitroglycerine (20 micrograms/Kg in 3 cc normal saline). Normal saline administration did not elicit any change, but nitroglycerine administration resulted in the following changes (mean +/- SE, paired statistics): systolic pulmonary artery pressure from 68 +/- 8 to 53 +/- 6 at 10 min into treatment (P 0.006), mean pulmonary artery pressure 47 +/- 4 to 38 +/- 4 (P 0.005), heart rate 131 +/- 8 to 127 +/- 7 (P 0.13), systolic blood pressure 85 +/- 8 to 88 +/- 3 (P 0.7), mean blood pressure 59 +/- 6 to 63 +/- 4 (P 0.5). These results indicate that nebulized nitroglycerine may be an effective, easy to administer, inexpensive, and safe alternative for treatment of severe pulmonary hypertension in children with congenital heart disease, especially in areas where other treatments such as extracorporeal membrane oxygenation or inhaled nitric oxide are inaccessible.

Aerosols↗

PubMedDate not supplied

Knot tying at flexible endoscopy.

Four new knotting techniques were developed for use at flexible endoscopy: (1) half hitches tied with knot-pusher, (2) thread-locking device, (3) self-tightening slip-knot, and (4) externally releasable knot. Remoteness from site of action, access through small-diameter orifice, and difficulty in applying lateral traction to tighten knots are problems met in knot tying at endoscopy. All four knotting techniques were studied in experiments on postmortem human stomachs and used for radio-telemetry studies and anti-reflux operations in survival studies in dogs using endoscopic sewing techniques. Half hitches tied at endoscopy with a knot-pusher were also used in human studies to treat esophageal reflux and secure pH radio-telemetry capsules for long-term measurements. Externally releasable knots were used to secure nasogastric tubes to the stomach of five patients for long-term nutrition. Knot tying is feasible at flexible endoscopy by a variety of new techniques. Endoscopically tied knots can be as secure as surgically hand-tied knots and have been used successfully in man.

Animals↗