Biomedical subjects

Hong-Kai Gao

Publications and source records attributed to Hong-Kai Gao.

7 recordsLinked to original sources

PubMed2006

Microcirculatory detection of Toll-like receptor 4 in rat pancreas and intestine.

This paper was aimed to detect Toll-like receptor 4 (TLR4) microcirculatory expression and localization in rat pancreas and intestine. Acute pancreatitis (AP) was induced by twice injections of cerulein (20 mug in total) and acute necrotizing pancreatitis (ANP) was induced by intraductal injection of 5% taurocholate (1 ml/kg.bw). Reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were used to detect and localize TLR4 in the pancreas and intestine. Results showed that RT-PCR of RNA isolated from pancreatic and intestinal tissue yielded the predicted amplicon for TLR4; IHC analysis localized TLR4 expression to the endothelium of pancreatic arteriole, venule, acinar capillary network and sinusoidal capillary of endocrine islet; TLR4 expression in intestine was principally in the microvascular endothelium and leucocytes within the mucosa lamina propria. TLR4 staining in intestine was more intense in taurocholate-induced pancreatitis (TIP) than that in cerulein-induced pancreatitis (CIP). In conclusion, TLR4 could be detected in the pancreatic and intestinal microcirculation, suggesting TLR4 involved in the microcirculatory impairment in AP; the more intense intestinal TLR4 expression in TIP suggests a potential risk for secondary infection.

Animals↗

PubMed2005

Differences in platelet endothelial cell adhesion molecule-1 expression between peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis.

AIM: To investigate the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis (AEP). METHODS: Fifty Wistar rats were randomly divided into control group (n = 10) and AEP group (n = 40). A model of AEP was established by subcutaneous injection of cerulein 5.5 and 7.5 mug/kg at 0 and 1 h after the beginning of experiment respectively. PECAM-1 expression on PMNs from splenic vein and inferior vena cava was determined by RT-PCR at mRNA level and determined by flow cytometry at protein level. RESULTS: In experimental rats, an increased PECAM-1 mRNA expression was seen from 4 to 8 h of AEP in peripheral circulation (0.77+/-0.25%, 0.76+/-0.28%, 0.89+/-0.30%, 1.00+/-0.21%), while in pancreatic microcirculation, expression decreased from 2 h and reached the lowest level at 6 h of AEP (0.78+/-0.29%, 0.75+/-0.26%, 0.62+/-0.28%, 0.66+/-0.20%). There were significant differences at 8-h time point of AEP between peripheral circulation and pancreatic microcirculation (1.00+/-0.21% vs 0.66+/-0.20%, P<0.05). Meanwhile, the difference at protein level was also found. CONCLUSION: A reverse expression of PECAM-1 on PMNs was found between peripheral circulation and pancreatic microcirculation, suggesting that inhibition of PECAM-1 expression may improve the pathological change of AEP.

Acute Disease↗

PubMed2005

Pituitary adenylate cyclase activating-peptide and its receptor antagonists in development of acute pancreatitis in rats.

AIM: Pituitary adenylate cyclase activating-peptide (PACAP) is a late member of the secretin/glucagon/vasoactive intestinal peptide (VIP) family of brain-gut peptides. It is unknown whether PACAP takes part in the development of acute pancreatitis and whether PACAP or its antagonists can be used to suppress the progression of acute pancreatitis. We investigated the actions of PACAP and its receptor antagonists in acute pancreatitis on rats. METHODS: Acute pancreatitis was induced in rats with caerulein or 3.5% sodium taurocholate. The rats were continuously infused with 5-30 microg/kg PACAP via jugular vein within the first 90 min, while 10-100 microg/kg PACAP6-27 and (4-Cl-D-Phe6, Leu17) VIP (PACAP receptor antagonists) were intravenously infused for 1 h. Biochemical and histopathological assessments were made at 4 h after infusion. Pancreatic and duodenal PACAP concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Chinese ink-perfused pancreas was fixed, sectioned and cleared for counting the functional capillary density. RESULTS: PACAP augmented caerulein-induced pancreatitis and failed to ameliorate sodium taurocholate-induced pancreatitis. ELISA revealed that relative concentrations of PACAP in pancreas and duodenum were significantly increased in both sodium taurocholate- and caerulein-induced pancreatitis compared with those in normal controls. Unexpectedly, PACAP6-27 and (4-Cl-D-Phe6, Leu17) VIP could induce mild acute pancreatitis and aggravate caerulein-induced pancreatitis with characteristic manifestations of acute hemorrhagic/necrotizing pancreatitis. Functional capillary density of pancreas was interpreted in the context of pancreatic edema, and calibrated functional capillary density (calibrated FCD), which combined measurement of functional capillary density with dry weight/wet weight ratio, was introduced. Hyperemia or congestion, rather than ischemia, characterized pancreatic microcirculatory changes in acute pancreatitis. CONCLUSION: PACAP may take part in the pathogenesis of acute pancreatitis in rats. The two PACAP receptor antagonsits might act as partial agonists. Calibrated functional capillary density can reflect pancreatic microcirculatory changes in acute pancreatitis.

Acute Disease↗

PubMed2004

Microscopic spread of low rectal cancer in regions of mesorectum: pathologic assessment with whole-mount sections.

AIM: To assess the microscopic spread of low rectal cancer in mesorectum regions to provide pathological evidence for the necessity of total mesorectal excision (TME). METHODS: A total of 62 patients with low rectal cancer underwent low anterior resection and TME, surgical specimens were sliced transversely on the serial embedded blocks at 2.5 mm interval, and stained with hematoxylin and eosin (HE). The mesorectum on whole-mount sections was divided into three regions: outer region of mesorectum (ORM), middle region of mesorectum (MRM) and inner region of mesorectum (IRM). Microscopic metastatic foci were investigated microscopically on the sections for the metastatic mesorectal regions, frequency, types, involvement of lymphatic vessels and correlation with the original rectal cancer. RESULTS: Microscopic spread of the tumor in mesorectum and ORM was observed in 38.7% (24/62) and 25.8% (16/62) of the patients, respectively. Circumferential resection margin (CRM) with involvement of microscopic metastatic foci occurred in 6.5% (4/62) of the patients, and distal mesorectum (DMR) involved was 6.5% (4/62) with the spread extent within 3 cm of low board of the main lesions. Most (20/24) of the patients with microscopic metastasis in mesorectum were in Dukes C stage. CONCLUSION: Results of the present study support that complete excision of the mesorectum without destruction of the ORM is essential for surgical management of low rectal cancer, an optimal DMR clearance resection margin should be no less than 4 cm, further pathologic assessment of the regions in extramesorectum in the pelvis is needed.

Adenocarcinoma↗

PubMed2004

Role of COX-2 in microcirculatory disturbance in experimental pancreatitis.

AIM: To elucidate the role of COX-2 in the development of capillary leakage in rats with acute interstitial pancreatitis. METHODS: Rats with acute interstitial pancreatitis were induced by caerulein subcutaneous injection. Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the gene expression of COX-2 in pancreatic tissues, spectrophotometry was used to assay the parameters of acute pancreatitis such as the serum amylase and plasma myeloperoxidase, and determination of capillary permeability in the pancreas by quantifying the permeability index (PI) assisted response of pancreatic microvascular via intravital fluorescence microscope video image analysis system. RESULTS: A significant increase of COX-2 expression, elevation of serum amylase, and plasma myeloperoxidase were detected in rats with acute edematous pancreatitis compared with control rats. The changes of pancreatic microvascular after caerulein injection were as following: (a) the decrease of pancreatic capillary blood flow (4th h, 0.56+/-0.09 nL/min, P<0.05; 8 th h, 0.34+/-0.10 nL/min, P<0.001); (b) reduction of functional capillary density (4 th h, 381+/-9 cm(-1), P>0.05; 8th h, 277+/-13 cm(-1), P<0.001); (c) irregular and intermittent capillary perfusion was observed at the 8th h and these vessels were also prone to permeation. CONCLUSION: COX-2 plays an important role in mediating capillary permeability in pancreatitis, thereby contributing to capillary leakage.

Animals↗

PubMed2004

Effects of TCMP-1 on the changes of platelet endothelial cell adhesion molecule-1 expression in acute edematous pancreatitis.

BACKGROUND: Traditional Chinese medicine is a potent agent in the management of clinical and experimental acute pancreatitis (AP), but the molecular mechanism of its therapeutic action is unclear. Numerous experimental and clinical studies have shown that platelet endothelial cell adhesion molecule-1 (PECAM-1) is pivotal to leukocyte recruitment, which results in microcirculatory injury during inflammation, but its role in acute pancreatitis is poorly understood. We investigated the effects of a compound of traditional Chinese medicine pancreatitis-1 (TCMP-1) on the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in acute edematous pancreatitis (AEP). METHODS: The model of acute pancreatitis was established by subcutaneous injection of caerulein, and TCMP-1 treated groups were given TCMP-1 by catheterization from mouth to stomach (20 ml/kg) immediately after first time subcutaneous injection of caerulein. The changes of expression of PECAM-1 on leukocytes from the blood of the splenic vein and inferior vena cava were determined by flow cytometry. RESULTS: In the AEP group, expression of PECAM-1 on PMNs was not significantly different between pancreatic microcirculation and systemic circulation at AEP2h and AEP4h time point. Then from AEP4h time point to AEP8h time point, expression of PECAM-1 was up-regulated in systemic circulation while it was down-regulated in pancreatic microcirculation and was significantly different between pancreatic microcirculation and systemic circulation at AEP8h time point (P<0.05). In the TCMP-1 treated group, compared with the AEP group, expression of PECAM-1 on PMNs decreased in different levels between pancreatic microcirculation and systemic circulation and was of significant difference at AEP8h time point (P<0.05). CONCLUSION: Inhibition of PECAM-1 expression on PMNs may prevent PMNs from transmigration through the endothelium and may be one of the treatment mechanisms of TCMP-1 decoction on AEP.

Acute Disease↗

PubMed2003

Expression of platelet endothelial cell adhesion molecule-1 between pancreatic microcirculation and peripheral circulation in rats with acute edematous pancreatitis.

OBJECTIVE: To study the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation and pancreatic microcirculation in rats with acute edematous pancreatitis (AEP). METHODS: The model of AEP was established with 50 Wistar rats, and the changes of PECAM-1 expression on PMNs from the splenic vein and inferior vena cava were determined by flow cytometry. RESULTS: PECAM-1 expression on PMNs showed no significant difference between pancreatic microcirculation and peripheral circulation at AEP2h and AEP4h time points. From the AEP4h to the AEP8h time point, PECAM-1 expression in peripheral circulation was up-regulated, but PECAM-1 expression in pancreatic microcirculation was down-regulated. PECAM-1 expression had a significant difference between pancreatic microcirculation and peripheral circulation at the AEP8h time point (P<0.05). CONCLUSION: PECAM-1 expression on PMNs is in a converse way between pancreatic microcirculation and peripheral circulation in AEP.

Acute Disease↗