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Biomedical subjects

T Hong

Publications and source records attributed to T Hong.

At least 37 records · Page 2Linked to original sources
PubMed2000

PTEN/MMAC1 expression in esophageal squamous cell carcinomas.

The PTEN/MMAC1 gene at 10q23.3 is a novel tumor suppressor gene candidate. Various kinds of tumors have mutations in this gene. However, in some cancers PTEN/MMAC1 gene may be inactivated by mechanisms other than gene deletion and mutation, including promoter methylation or translational modification. The aim of this study was to determine whether there are abnormalities in the expression of PTEN/MMAC1 gene in esophageal cancer. Reverse transcription polymerase chain reaction and western blot were used to examine PTEN/MMAC1 expression in human esophageal squamous cell lines and normal cultured esophageal epithelial cells. Immunohistochemical staining was carried out to detect PTEN/MMAC1 expression in surgically resected esophageal squamous cell carcinomas and normal esophageal epithelium. All 30 esophageal cancer cell lines (KYSE series) and normal cultured esophageal epithelial cells expressed PTEN/MMAC1 mRNA. Western blot analysis confirmed that all the cell lines expressed PTEN/MMAC1 protein and there was no difference in expression level. Immunohistochemical study showed that the PTEN/MMAC1 protein was localized dominantly in the cytoplasm and strongly stained in all 42 surgically resected esophageal squamous cell carcinomas and normal esophageal epithelium. PTEN/MMAC1 is rarely associated with esophageal squamous cell carcinoma carcinogenesis.

Carcinoma, Squamous Cell↗
PubMed2000

Reproducible echocardiography in juvenile sheep and its application in the evaluation of a pulmonary valve homograft implant.

Increased use of the ovine animal model in cardiovascular surgical research has created a salient need for standardized echocardiography techniques. To demonstrate a reproducible image in this species and confirm the validity of echocardiography as a diagnostic tool, we implanted 10 sheep with a pulmonary valve homograft and monitored them through weekly echocardiographic examinations until 20 weeks after implantation. We obtained good images from the left cranial and the left caudal transducer windows without needing to sedate the animals. Sedated sheep yielded adequate views from the right apical window. Echocardiographic data on the implanted homografts (including functional capacity, presence of calcification, and hemodynamic information and measurements), completely agreed with the results of the post-explantation examinations.

Animals↗
PubMed2000

Epidemiology of human geohelminth infections (ascariasis, trichuriasis and necatoriasis) in Lushui and Puer Counties, Yunnan Province, China.

Between April and June of 1998, the prevalence and intensity of geohelminth infections caused by hookworm, Ascaris and Trichuris were investigated in two rural Yunnan villages. In Liuku, a village of Lisu indigenous people in Lushui County, there was an overall geohelminth prevalence of 72% (48%, 43% and 16% for hookworm infection, ascariasis, and trichuriasis, respectively). The prevalence of ascariasis was greatest among preschool and school aged children, whereas the prevalence of trichuriasis was greatest among teenagers and the prevalence of hookworm increased until the age of 10-15 and then remained high throughout adulthood. In Linger, a village of Han Chinese, located in Puer County, there was an overall geohelminth prevalence of 77% (30%, 60% and 36% for hookworm infection, ascariasis, and trichuriasis, respectively). The differences in prevalence for hookworm and ascariasis were statistically significant. The prevalence of hookworm in Linger increased steadily with age and did not plateau, but there were no discernible patterns of prevalence versus age for either ascariasis or trichuriasis. Heavy trichuriasis infections were noted to occur in Linger. In both villages, more than 98% of the hookworm infections were of light and moderate intensity. Both by morphologic identification of third-stage infective larvae (L3) from eggs as well as identification of adult hookworms recovered from adult residents after treatment with quantrel, Necator americanus was identified as the exclusive hookworm in each village. Geohelminth infections caused by Ascaris, Trichuris and hookworm remain highly endemic to the rural areas of Yunnan Province in southwestern China.

Adolescent↗
PubMed1999

Motility-related protein (MRP-1/CD9) and KAI1/CD82 expression inversely correlate with lymph node metastasis in oesophageal squamous cell carcinoma.

Although the mechanisms of action of the transmembrane superfamilies, motility-related protein-1 (MRP-1/CD9) and KAI1/CD82, are not well known, they are reported to suppress the metastasis of several kinds of cancers. The suppression of cell motility by MRP-1/CD9 may cause suppression of the metastasis. As we could not find any reports concerning the expression of MRP-1/CD9 and KAI1/CD82 in oesophageal cancers we investigated their expression in oesophageal specimens. We conducted immunohistochemical staining for MRP1/CD9 against 108 cases of oesophageal squamous cell carcinoma using anti-MRP-1/CD9 monoclonal antibody M31-15, and for KAI1/CD82 against 104 cases using anti-KAI1/CD82 monoclonal antibody C33. To investigate the gradual expression of MRP-1/CD9 and KAI1/CD82, 24 oesophageal dysplasias were immunohistochemically stained using the same method and then investigated. The expression of both MRP-1/CD9 and KAI1/CD82 were positive on the cell membranes of normal oesophageal epithelial cells, but reduced or negative in the cancer cells. Reduced MRP-1/CD9 expressions significantly correlated to tumour depth (P = 0.0009). We found a significantly greater number of reduced or negative expression of MRP-1/CD9 and KAI1/CD82 in lymph node metastatic cases (P = 0.0003 and P= 0.0129, respectively), but not in distant metastatic cases. The 5-year survival rate of MRP-1/CD9-negative and reduced patients was significantly worse than those of positive patients (n = 108, curative cases, RO). Few cases remained KAI1/CD82-positive (9.6%; 10/104) in oesophageal cancer. Twenty (83.3%) and twenty-two (91.7%) cases out of 24 dysplasias were defined as KAI1/CD82-positive and MRP1/CD9-positive, respectively. The decrease in MRP-1/CD9 and KAI1/CD82 expression may facilitate lymph node metastasis in oesophageal squamous cell carcinomas. Knowing the status of the expression of MRP-1/CD9 appears helpful in predicting the prognosis for each patient.

Adult↗
PubMed1998

Restricted expression of the gap junctional protein connexin 43 in the arterial system of the rat.

Connexin 43 (Cx43) has been reported to be expressed in vascular smooth muscle cells and endothelial cells. Evidence for possible variations in Cx43 distribution within different parts of the vascular system is limited. We have therefore investigated the expression of Cx43 in the endothelia and media of 11 vessels of different size and function in the rat, using immunofluorescence and confocal laser scanning microscopy. The results showed that punctate Cx43 staining was abundant in the endothelia and media of all of the 5 elastic arteries examined. In the media, the amount of Cx43 staining decreased as the size of the elastic arteries became smaller. In the 6 muscular arteries examined, 2 different patterns of Cx43 staining were observed. In the first type, Cx43 expression was high in the endothelium but virtually absent from the media. Mesenteric resistance, hepatic and tail arteries were examples. In the second type, Cx43 staining was absent from both the media and the endothelia. The coronary, basilar, and middle cerebral arteries showed this appearance. The results suggest that expression of Cx43 is largely restricted to elastic arteries in the arterial system of the rat. The lack of immunodetectable Cx43 from the media of all muscular arteries examined, and from the endothelia of some of these arteries, raises the possibility of significant differences in the form of expression of Cx43 in these vessels or the presence of other connexins.

Animals↗
PubMed1998

Coronary angiographic characteristics in unstable angina pectoris.

OBJECTIVE: To investigate the angiographic characteristics of coronary lesions in patients of different subgroups of unstable angina pectoris. METHODS: Coronary angiograms and clinical manifestations were analysed on 388 patients. RESULTS: Single-vessel disease was more common in new onset effort angina (69.64%) than in other subgroups (P < 0.05); triple-vessel disease and left main coronary artery disease appeared more frequently in patients with rest angina than in other subgroups (72.34% and 27.66% respectively, P < 0.05), so did complex lesions and type C lesions (36.07% and 60.64% respectively, P < 0.05). More than half of the culprit lesions in post-infarction angina were subtotal or total occlusions (53.12%), being more frequently found in this than in other subgroups (P < 0.05). Most of the patients with Prinzmetal variant angina had mild coronary lesions only. Coronary thrombi were found in 10.45% of the 388 patients; they were more frequent in patients with post-infarction angina (20.00%) than in the subgroups of new onset effort angina, aggravated effort angina and Prinzmetal variant angina (4.26%, 7.53% and 0% respectively, P < 0.05). Coronary thrombi were also more frequent in patients with chest pain at rest (16.39%) than in the subgroups of new onset effort angina and Prinzmetal variant angina (P < 0.05). CONCLUSIONS: It is suggested that patients with angina at rest should be treated more intensively. Energetic anticoagulation treatment should be given to patients with post-infarction angina and angina at rest.

Adult↗
PubMed1997

In vitro and in vivo studies of a polyester arterial prosthesis with a warp-knitted sharkskin structure.

The present study was undertaken to assess the performance of a new knitted and gelatin-sealed polyester vascular graft that is believed to have greater dimensional stability than current commercial devices. Samples of the uncrimped, crimped, and sealed prosthesis were submitted to a series of in vitro and in vivo trials. Four commercial polyester knitted devices were included as controls for the in vitro tests, which included measurements of the textile and yarn structure and physical, chemical, and thermal properties of the graft, such as water permeability, dilatation, suture retention strength, melting point, and crystallinity index. The in vivo evaluation involved implanting the prototype device as a canine thoraco-abdominal bypass for periods ranging from 4 h to 1 year and assessing the biocompatibility, biofunctionality, and biostability of the explanted specimens. The warp-knitted structure of the prototype device has a unique sharkskin stitch that confers a superior dilatation resistance and suture retention strength to the prosthesis. The animal trial demonstrated that the gelatin ensures initial hemostasis without preclotting. The gelatin is bioresorbed during the first 2 weeks of implantation, which generates a temporary, moderate, acute inflammatory response. An external capsule of granulomatous tissue and an internal collagen capsule are formed between the first and third month. Analysis of the textile and physical properties of the explanted prostheses confirmed there was neither dilatation nor significant changes in structure or mechanical performance during implantation, thus confirming the biostability of this new prototype device and opening the way for clinical trials.

Anastomosis, Surgical↗
PubMed1997

N-terminal sequences from Autographa californica nuclear polyhedrosis virus envelope proteins ODV-E66 and ODV-E25 are sufficient to direct reporter proteins to the nuclear envelope, intranuclear microvesicles and the envelope of occlusion derived virus.

Baculovirus occlusion-derived virus (ODV) derives its envelope from an intranuclear membrane source. N-terminal amino acid sequences of the Autographa californica nuclear polyhedrosis virus (AcMNPV) envelope proteins, ODV-E66 and ODV-E25 (23 and 24 amino acids, respectively) are highly hydrophobic. Recombinant viruses that express the two N-terminal amino acid sequences fused to green fluorescent protein (23GFP or 24GFP) provided visual markers to follow protein transport and localization within the nucleus during infection. Autoflourescence was first detected along the cytoplasmic periphery of the nucleus and subsequently localized as foci to discrete locations within the nucleus. Immunoelectron microscopy confirmed that these foci predominantly contained intranuclear microvesicles and the reporter fusion proteins were also detected in cytoplasmic membranes near the nucleus, and the outer and inner nuclear membrane. Therefore, these defined hydrophobic domains are sufficient to direct native and fusion proteins to induced membrane microvesicles within a baculovirus-infected cell nucleus and the viral envelope. In addition, these data suggest that movement of these proteins into the nuclear envelope may initiate through cytoplasmic membranes, such as endoplasmic reticulum, and that transport into the nucleus may be mediated through the outer and inner nuclear membrane.

Amino Acid Sequence↗
PubMed1997

A sensitive ocular perfusion apparatus measuring outflow facility.

PURPOSE: To build an improved apparatus for measuring outflow facility by one- and two-level, constant pressure perfusion. METHODS: A computer-controlled and -monitored tower adjusts the height of a fluid reservoir by a stepper motor every 5 min, to keep intraocular pressure (IOP) constant at one or two desired pressure levels (e.g. 2.5 and 12.0 mm Hg above the spontaneous IOP). The fluid flow rate is calculated by the equation Q = (Pres - IOP)/R, where Pres is the pressure of the reservoir as calculated by the term "pgh," h being the height of the reservoir, measured by the rotation of stepper motor, g, the gravity constant, and p, the fluid density. IOP is measured by the transducer, and R is the resistance of 180 microns tubing. Outflow facility is calculated by delta Q/ delta P. delta Q is the difference between flow rate at the two pressure levels, and delta P is the intraocular pressure difference. Perfusion was performed on live albino rat eyes by the two-level constant pressure technique, and on artificial steel eyes at a single constant pressure perfusion (20 mm Hg). RESULTS: Outflow facility of albino rat eyes and artificial steel eyes perfused for 40 and 30 min, respectively was 0.0507 +/- 0.0039 microliter/min/mm Hg and 0.3546 +/- 0.0034 microliter/min/mm Hg (mean +/- SD), respectively. CONCLUSIONS: Our perfusion apparatus is highly stable, sensitive, and capable of measuring subtle changes in outflow facility in vivo and in vitro.

Animals↗
PubMed1997

[Operative treatment of displaced acetabular fractures through the ilioinguinal approach].

To reduce the incidence of ectopic ossification and improve hip joint function after the operative treatment of displaced acetabulum fractures. We surgically treated 12 acetabular fractures which involved anterior column or both anterior and posterior column fractures through the ilioinguinal approach. 10 patients were judged postoperatively to have an anatomic reduction, and 2 had a satisfactory reduction. An average of 3-year follow-up showed excellent results in 8 patients (67%) and good in 4 (33%). Radiographic results indicated excellent results in 8 (67%), patients good in 3 (25%), fair in 1 (8%). The results suggested that the ilioinguinal approach appears to diminish many of the problems associated with utilization of an extrapelvic approach, including the disturbances of the hip abductor system, heterotopic ossification, sciatic palsy, the slow recovery of hip mobility. We conclude that it is not only good for an operative treatment of anterior column fractures but also good for some of posterior column fractures.

Acetabulum↗
PubMed1997

[Pharmacological studies of luohanguo yanhou tablet].

Luohanguo Yanhou Tablet possesses the action of cotton ball granuloma of mice and the auricular edema induced by xylol, and also inhibiting the swelling of rat hind paw induced by carrageenin. The tests of mice writhing induced by acetic acid showed that the preparation had obvious analgesic action. It also possesses the obvious bacteriostatic action in vitro on five kinds of strains.

Analgesics↗
PubMed1996

Direct application of Etest to gram-positive cocci from blood cultures: quick and reliable minimum inhibitory concentration data.

The Etest was applied directly to 100 Gram-positive bacterial strains from blood cultures to measure their minimum inhibitory concentration (MIC). Results showed 100% concordance of MIC data between a direct Etest method and the standard Etest method for Streptococcus pneumoniae, beta-hemolytic streptococci, and viridans group streptococci. In addition, direct Etest for Staphylococcus aureus, coagulase negative staphylococci, Enterococcus faecium, and Enterococcus faecalis showed 83 to 100% correlation with standard Etests. These data indicate that the Etest is useful to obtain MIC data on Gram-positive cocci (especially streptococci) directly from positive blood cultures. The advantages of a direct Etest are two fold: MIC results can be obtained 24 hours earlier than standard methods and a more representative population of the bacterial isolate is tested.

Anti-Bacterial Agents↗
PubMed1996

[The protective effect of nicotinamide on interleukin-1 beta induced damage to rat islets of Langerhans and its mechanism].

OBJECTIVE: To investigate the protective effects of nicotinamide (NA) on newborn rat islets of Langerhans. METHODS: Newborn rat islets were isolated by digestion of collagenase V. The effects of IL-1 beta and/or NA on insulin release and nitric oxide (NO) production and 3H-thymidine incorporation were studied. RESULTS: NA had no effects on both accumulated insulin release and insulin release at an acute glucose challenge, but increased 3H-thymidine incorporation. 25 mmol/L of NA reduced the inhibition of accumulated insulin release and 3H-thymidine incorporation induced by 40/ml of IL-1 beta. However. NA was not able to reverse the reduced ability of IL-1 beta-treated islets to respond to an acute glucose challenge. NA dose-dependently reduced NO production induced by IL-1 beta. CONCLUSION: There is the protective effect of NA on IL-1 beta-induced damage to islets of Langerhans. The mechanism of this effect might be related to that NA stimulates islet cells replication and reduces NO production induced by IL-1 beta.

Animals↗
PubMed1996

[Coronary angiographic characteristics of patients with unstable angina].

In order to study the characteristics of coronary lesions of patients with unstable angina, coronary angiograms and clinical manifestations were analysed on 388 patients. The results were as follows: single vessele disease was more common in new onset effort angina (69.64%) than in other groups (P < 0.05). Triple vessele disease and left main coronary artery lesion appeared more frequently in patients with rest angina than in other groups (72.34% and 27.66% respectively, P < 0.05), so did complex lesions and type C lesions (36.07% and 60.64% respectively, P < 0.05). More than half of the culprit lesions in early postinfarction angina was subtotal or total occlusions (53.12%), being more frequently found in this than in other groups (P < 0.05). Most of the patients with Prinzmetal variant angina had mild coronary lesions only. Coronary thrombi were found in 10.45% of the 388 patients; they were was more frequent in patients with early postinfarction angina (20.00%) than in the groups of new onset effort angina, aggravated effort angina and Prinzmetal variant angina (4.26%, 7.53% and 0% respectively, P < 0.05). Coronary thrombi were also more frequent in the patients with chest pain at rest (16.39%) than in the groups of new onset effort angina and Prinzmetal variant angina (P < 0.05). It is suggested that patients with angina at rest should be treated more intensively. Strengthened anticoagulation treatment should be given to patients with early postinfarction angina and angina at rest.

Adult↗
PubMed1996

[Microsurgical treatment of cavernous sinus tumor].

We studied 25 cases of cavernous sinus tumors who underwent microsurgical operation. The tumors were mainly composed of neurinomas and meningiomas. The tumors of 8 of 9 cases of the former, and 4 of 6 cases of the latter were totally removed. None of the patients died. We discussed the operative, method, preoperative preparation and postoperative complication.

Adolescent↗
PubMed1995

Evidence to suggest nitric oxide is an interstitial regulator of Leydig cell steroidogenesis.

Recent studies have suggested that nitric oxide (NO) may function as both an intracellular and intercellular signal that affects neural and immunological activity, vascular tone, platelet adhesion, and production of some hormones. Arginine analogs such as NG-monomethyl-L-arginine (L-NMMA) and N omega-nitro-L-arginine methyl ester (L-NAME) act to inhibit the intracellular formation of NO and have been used to study the effects of decreased NO formation on physiological systems. A single in vivo study has suggested that a similar analog, NG-nitro-L-arginine, increases serum testosterone (T), but the organ site and mechanism of action were not investigated. The present study was performed to investigate the effects of NO synthase inhibitors on Leydig cell function. L-NMMA and L-NAME, but not the inactive enantiomer (D-NMMA), increased both basal and human chorionic gonadotropin (hCG)-stimulated T production while decreasing guanosine 3':5'-cyclic monophosphate (cGMP). There was no effect on either adenosine 3':5'-cyclic monophosphate (cAMP) accumulation or specific hCG binding. These results suggest that NO formation, which is inhibited by L-NMMA and L-NAME, is important in the regulation of Leydig cell T production by interstitial cells of the testis, and that changes in cGMP levels might be involved in this process.

Animals↗