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Meng Ngu

Publications and source records attributed to Meng Ngu.

5 recordsLinked to original sources
PubMed2003

c-Fos immunoreactivity in the brain after esophageal acid stimulation.

The goal of this study was to use c-Fos immunohistochemistry to establish a rat model for studying the central projection of the esophageal afferent neurons during acid exposure. A cannula was placed in the esophagus of anesthetized Wistar rats with the tip approximately 2 cm above the lower esophageal sphincter (LES). Hydrochloric acid (0.1 N HCl, 50 mmol/L) with pepsin (3,200-4,500 U/mL), at pH 1.6, was then perfused into the esophagi of the experimental rats (n = 8) at 10 mL/hr continuously for 50 minutes. Normal saline solution (0.9% NaCl) was used in control rats (n = 6), and home cage control animals (n = 6) were given no stimulation. Thirty minutes after the perfusion, the rat was killed and the brain was removed and processed for c-Fos immunohistochemistry. A transverse section of the esophagus, 2 cm above the LES, was stained with hematoxylin and eosin stain for light microscopy. c-Fos immunoreactivity was significantly increased in a number of brain regions in the rats receiving the acid plus pepsin perfusion. These areas included the central amygdala, the Kölliker-Fuse nucleus, the nucleus of the solitary tract (NTS), the medial part of the NTS, the interstitial part of the NTS, the commissural part of the NTS, the paratrigeminal nucleus, the ambiguus nucleus, and the rostroventrolateral recticular nucleus. Perfusion with acid-pepsin solution also resulted in morphologic changes in the esophagus on light microscopy. This study suggests that acid plus pepsin perfusion of esophagus results in both neural activation in areas of the central nervous system and damage to the esophagus in an animal model.

Animals↗
PubMed2003

Hepatic sinusoidal pseudocapillarization with aging in the non-human primate.

BACKGROUND/AIMS: Age-related changes in the hepatic sinusoid termed pseudocapillarization have been reported in the rat and human and have implications for disease susceptibility in old age. In this study, we investigated whether similar changes occur in the livers of old baboons and thus represent a widespread aging change. METHODS: Liver tissue from five young baboons (5.4+/-0.5yrs) and five old baboons (21.8+/-0.7yrs) was compared by transmission electron microscopy, scanning electron microscopy and immunohistochemistry. RESULTS: The thickness of the sinusoidal endothelium was increased in old baboons (130+/-8 nm versus 186+/-9 nm, P<0.001) and the frequency of endothelial fenestrae decreased, with the porosity declining from 4.2+/-0.5% to 2.4+/-0.4% (P=0.006). The expression of laminin and von Willebrands factor was more extensive in old baboons. Novel perisinusoidal ring-shaped cells, probably fat-engorged stellate cells, were prominent in the old baboons. CONCLUSIONS: Pseudocapillarization is a significant age-related change in the baboon liver. Aging in baboons is associated with a novel aging change in the stellate cell not reported in other species. Hepatic pseudocapillarization is a widespread aging liver change found in several species including humans and other non-human primates.

Aging↗
PubMed2002

Factors associated with severity of hepatic fibrosis in people with chronic hepatitis C infection.

OBJECTIVE: To determine factors associated with hepatic fibrosis development in people with chronic hepatitis C virus (HCV) infection. METHODS: As a requirement for access to interferon therapy through the S100 scheme in Australia, individual pretreatment demographic and clinical information was collected on 2986 patients from 61 hospital-based liver clinics from 1 October 1994 through 31 December 1996. Patients with both a hepatic fibrosis score and an estimated duration of HCV infection (910) were divided into 540 with no or minimal hepatic fibrosis (stage 0-1) and 370 with moderate to severe hepatic fibrosis (stage 2-3). Seven factors were examined: age at HCV infection, sex, ethnicity, source of infection, duration of infection, alcohol intake, and mean ALT level. A further analysis was performed for all 1135 patients with a hepatic fibrosis score disregarding age at and duration of HCV infection. RESULTS: In multivariate analysis, four factors were significantly associated with moderate to severe hepatic fibrosis: age at infection (OR, 2.33 for age 31-40 years, 5.27 for age > 40 years, and 0.20 for age < 15 years, compared with 15-20 years); duration of infection (OR, 1.44 for 11-20 years, 2.74 for 21-30 years, and 8.71 for > 30 years, compared with < 11 years); alcohol intake in previous six months (OR, 1.51 for any intake, compared with none); and mean ALT level (OR, 1.81 for 2-3 times, 2.27 for > 3 times, compared with 1.5-2 times the upper limit of normal). In the analysis disregarding age at HCV infection and duration of HCV infection, older age was strongly associated with moderate to severe hepatic fibrosis (OR, 2.32 for age 36-40 years, 2.46 for age 41-50 years, 7.87 for age 51-60 years, and 7.15 for age > 60 years, compared with 16-30 years). There was no association in either analysis with sex or source of HCV infection. CONCLUSION: These factors may assist in targeting patients for both liver biopsy-based investigation and therapeutic intervention.

Adolescent↗