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Biomedical subjects

C L Lu

Publications and source records attributed to C L Lu.

At least 19 recordsLinked to original sources
PubMed2001

Glial cell line-derived neurotrophic factor enhances axonal regeneration following sciatic nerve transection in adult rats.

Adult rat sciatic nerve was transected and sutured with an entubulation technique. The nerve interstump gap was filled with either collagen gel (COL) or collagen gel mixed with glial cell line-derived neurotrophic factor (COL/GDNF). Four weeks after nerve transection, horseradish peroxidase (HRP)-labelled spinal cord motoneurons and the myelinated distal stump axons were quantified. Compared with the COL group, the percentages of labeled spinal somas and axon number were significantly increased after topically applied glial cell line-derived neurotrophic factor (GDNF). The functional recovery of the transected nerve was improved in COL/GDNF group. GAP-43 expression was also significantly higher in COL/GDNF group 1 and 2 weeks after sciatic nerve axotomy vs. COL group. These data provide strong evidence that GDNF could promote axonal regeneration in adult rats, suggesting the potential use of GDNF in therapeutic approaches to peripheral nerve injury and neuropathies.

Animals↗
PubMed2001

The expression of G-protein-gated inwardly rectifying K+ channels GIRK1 and GIRK2 mRNAs in the supraoptic nucleus of the rat and possible role involved.

The expression of G-protein-gated inwardly rectifying K channels subunits GIRK1 and GIRK2 mRNAs in the supraoptic nucleus (SON) was investigated in the rat by in situ hybridization with non-radioactive dig-labeled cRNA probes. Double-labeled methods were used to study the co-localization of GIRK1 and 2 and oxytocin (OT) and vasopressin (AVP) in the SON. The present study revealed wide and intense expression of GIRK1 and GIRK2 mRNAs with high overlapping in the SON, indicating the heterologous channel of GIRK1/GIRK2 was a major functional channel in the SON. Given that 100% of OT-positive and 95% of (AVP)-positive neurons in the SON expressed GIRK1/GIRK2 mRNAs, it is possible that GIRK1/GIRK2 channel, activated through G-protein coupled receptors, may be involved in the inhibitory regulation of the release of OT and AVP from the SON.

Animals↗
PubMed2001

Adult human olfactory stem cells.

The location of stem cells within the adult CNS makes them impractical for surgical removal and autologous transplantation. Their limited availability and histocompatibility issues further restrict their use. In contrast, olfactory neuroepithelium (ONe) located in the nasal passageways has a continuous regenerative capability and can be biopsied readily. To investigate the potential of human ONe to provide viable populations of pluripotent cells, ONe was harvested from cadavers 6-18 h postmortem, dissociated, plated and fed every 3-4 days. Heterogeneous populations of neurons, glia, and epithelia were identified with lineage-specific markers. After several weeks, 5-10% of the cultures produced a population of rapidly dividing cells, which in turn, produced neurospheres containing at least two subpopulations based on neuronal and glial specific antigens. Most contained one or more neuronal markers; a few were positive for A2B5 and/or GFAP. To determine if growth modulators would affect the neurosphere forming cells, they were exposed to dibutyryl-cAMP. The nucleotide reduced cell division and increased process formation. Although the cells had been passaged more than 70 times, their viability remained constant as shown by the MTT viability index. Donor age or sex were not limiting factors, because neurospheres have been established from cadavers of both sexes from 50 to 95 years old at time of death. The ex vivo expansion of these cells will provide a patient-specific population of cells for immunological, genetic and pharmacological evaluation. Our long-term goal is to determine the utility of these cells to facilitate CNS repair.

Aged↗
PubMed2001

Real-time display of the stomach slow wave and its parameters in a newly designed electrogastrographic system.

We designed a new three-channel electrogastrographic (EGG) system, which was easily operated on the Windows 95 platform and could automatically provide slow wave parameters. The purpose of the present study was to test its reliability and accuracy in clinical recording. The system included a signal acquisition device assembled on a printed circuit board. Recorded myoelectrical signals were filtered, amplified, digitized, and transmitted via this device into a notebook personal computer (PC). Based on the short-term Fourier transform the software could transfer the time domain of the signal into the frequency domain. Real-time displayed slow wave parameters, including dominant frequency/power, percent of normal frequency (2-4 cpm), instability coefficient in frequency/power, and power ratio, were automatically renewed every 64s. Twenty healthy subjects (M/F, 12/8; age, 23-51 years) were enrolled to measure both fast and postprandial myoelectrical activities for each 30-min recording. Our results indicated that meal ingestion significantly increased dominant frequency (3.15+/-0.20 vs 3.23+/-0.23 cpm; P < 0.05) and power (26.1+/-3.8 vs 28.4+/-3.9 dB; P < 0.05). The power ratio of the meal effect was 2.02+/-2.07. Other parameters, including instability coefficient and percent of normal frequency, remained similar despite food ingestion. This newly designed EGG system is acceptable for clinically measuring gastric myoelectrical activity; the real-time display of many EGG parameters is an advantage with this new system.

Adult↗
PubMed2001

Oxytocin mediates the inhibitory action of acute lithium on the morphine dependence in rats.

The role of central oxytocin in inhibitory action of lithium on the development of morphine dependence was behavioral investigated in rats. Acute lithium could enhance the morphine-induced analgesia in rats with or without chronic morphine treatment; this effect could be inhibited by intraventricular injection of oxytocin antagonist d (CH(2))(5)-Tyr (Me)-[Orn(8)]-Vasotocin (OVT). Lithium could attenuate naloxone-precipitated withdrawal signs in morphine dependent rats. The reduction of the expression of naloxone-precipitated withdrawal signs by lithium was reversed by ICV of OVT. The lithium significantly inhibited the conditioned place preference (CPP) induced by morphine, which inhibitory action of lithium could also reverse by ICV injection of OVT. These results suggested that lithium might inhibit the physical dependence on morphine as well as psychological dependence in rats, and that this inhibitory effect of lithium on the development of morphine dependence might be associated with oxytocin systems in the central nervous system.

Analgesics, Opioid↗
PubMed2001

Impaired postprandial gastric myoelectrical activity in Chinese patients with nonulcer dyspepsia.

Using a homemade electrogastrography (EGG) system, we studied the characteristics of the myoelectrical rhythm in Chinese patients with nonulcer dyspepsia (NUD). Based on short-term Fourier transformation, recorded slow waves could be automatically analyzed to obtain the following parameters: dominant frequency/power, percent of normal frequency (2-4 cpm), power ratio, etc. EGG parameters, Helicobacter pylori status, histological examination of gastric mucosa, and dyspeptic symptoms were recorded in 27 NUD patients. Compared to 32 healthy controls, the Chinese NUD patients had abnormal postprandial EGG parameters including a lower percentage of regular 2-4 cpm slow waves (70.10 +/- 2.97% vs 79.08 +/- 2.95%, P < 0.05), a lower level of increment of dominant power (0.62, +/- 0.91 vs 3.76 +/- 0.58 dB, P < 0.05), lower power ratio (1.42 +/- 0.28 vs 2.79 +/- 0.39, P < 0.05) and a higher instability coefficient (0.36 +/- 0.03 vs 0.26 +/- 0.03, P < 0.05). However, Helicobacter pylori infection and its associated gastritis did not influence any EGG parameters in NUD patients. Six main dyspeptic symptoms and total symptom score had no correlation with any EGG parameters. In conclusion, Chinese NUD patients may have abnormal postprandial stomach myoelectrical activity, but these EGG abnormalities are not a direct result of Helicobacter pylori infection and its related gastritis and do not contribution to the dyspeptic symptoms.

Adult↗
PubMed2001

Applied potential tomography in liquid gastric emptying measurement: design, assembling, calibration, and clinical application.

The present study aimed to validate the accuracy of a homemade applied potential tomography (APT) apparatus for liquid gastric emptying (GE). Twelve electrodes were placed in a circular array around the subjects. Ten electrodes in a rotated order recorded electrical current delivered from a driving pair of electrodes. Based on tomography, averaged signals of changed resistivity were constructed to display area changes. Six beakers were respectively placed into a saline-filled Perspex tank to measure their cross-sections. True beaker cross-sections are 2.01, 15.9, 18.8, 30.19, 38.48, and 63.61 cm2, respectively, whereas APT generated cross-sections were 7.9 +/- 2.9, 16.7 +/- 3.3, 22.4 +/- 4.9, 28 +/- 4.8, 48.7 +/- 7.6, 67 +/- 6.1 cm2, respectively (r = 0.98, P < 0.001). Twenty-four healthy males ingested 500-ml test solution to assess GE using both APT and scintigraphy. Only 20 (83.3%) subjects had a successful measurement. The APT half emptying time was 15.6 +/- 4.8 min, whereas scintigraphy was 21.9 +/- 6.3 min (r = 0.67, P < 0.01). In conclusion, our APT apparatus is a simple, noninvasive, and inexpensive way to assess liquid GE. Its clinical usefulness is confirmed using both phantom and human models.

Adult↗
PubMed2001

Electrogastrographic characteristics in patients of stomach cancer.

Using a homemade electrogastrography (EGG) system, we studied the characteristics of myoelectrical rhythm in gastric cancer (GC) patients. Based on a short-term Fourier transform, recorded slow waves could be automatically analyzed to obtain the following parameters: dominant frequency/power, percent of normal rhythm (2.4-3.7 cpm), power ratio, etc. Fifty histologically confirmed GC patients (34 men, 16 women) were enrolled before surgical intervention to measure their fasting and postprandial EGG parameters for 30 min. The cancerous parameters of GC patients were then obtained postoperatively. In addition, 46 healthy subjects were enrolled for comparison. When compared to controls, GC patients had the following characteristics: absence of postprandial increase in dominant frequency (GC: 3.04 +/- 0.47 vs 3.07 +/- 0.44 cpm, NS; controls: 3.02 +/- 0.31 vs 3.21 +/- 0.25 cpm, P < 0.001), marked power response after meal (P < 0.05), and obvious power ratio (4.58 +/- 7.38 vs 2.27 +/- 2.05, P < 0.05). Multivariate analysis indicated that advanced GC was the factor responsible for the obvious dominant power enhancement after meal (P < 0.05). Other demographic, clinical, and cancerous factors did not influence EGG parameters. We conclude that apparent arrhythmia is not encountered in GC patients, although they mainly exhibit obvious postprandial power response. Advanced GC is likely responsible for this power enhancement on EGG recording.

Aged↗
PubMed2001

Adult intussuscepted Meckel's diverticulum presenting mainly lower gastrointestinal bleeding.

Herein, we report on an adult with intussusception of an invaginated Meckel's diverticulum presenting mainly with acute intermittent lower gastrointestinal bleeding, whereas the common symptom of abdominal pain, indicating intussusception, was absent. Colonoscopy revealed a reducible polypoid lesion in the ileocecal area. Computed tomography led to suspicion of an intussusception. Surgical resection revealed a Meckel's diverticulum containing an aberrant pancreas. The unique clinical symptoms and the methods of diagnosis are discussed.

Adult↗
PubMed2001

Hepatic steatosis in chronic hepatitis C virus infection: prevalence and clinical correlation.

BACKGROUND AND AIMS: Hepatic steatosis is a histological characteristic in patients with chronic hepatitis C virus (HCV) infection. The aim of this study was to evaluate the prevalence of hepatic steatosis in Chinese patients with chronic hepatitis C, and to look for possible correlation with various histopathological changes and to look for possible correlation with various clinical and pathologic variables. METHODS: One hundred and six patients were enrolled, and patients with alcoholism or diabetes mellitus were excluded. Clinical, biochemical and virologic data, including HCV genotype and serum HCV-RNA titer and histological findings, were compared between patients with and without hepatic steatosis. RESULTS: Fifty-five (52%) of the 106 patients with chronic hepatitis C had hepatic steatosis. Patients with hepatic steatosis had significantly higher mean serum levels of triglyceride and gamma-glutamyl transpeptidase, higher body mass index, and a higher incidence of obesity compared with patients without hepatic steatosis. No significant differences in serum HCV-RNA titer and HCV genotype or the response to interferon therapy were noted between the two groups. Histological analysis showed patients with hepatic steatosis had a significantly higher mean fibrotic score than patients without hepatic steatosis (1.9 +/- 1.2 vs 1.3 +/- 1.0; P = 0.016). There were no significant differences in the severity of necroinflammation, the presence of lymphoid aggregation/follicle or bile duct damage between the two groups. Multivariate logistic regression analysis showed that independent predictors associated with hepatic steatosis were obesity or a histology fibrotic score of > or = 2. CONCLUSION: It was found that 52% of Chinese patients with chronic hepatitis C had hepatic steatosis. Patients with hepatic steatosis were more frequently obese and had more severe hepatic fibrosis.

Adult↗
PubMed2001

Diagnosis of appendicitis in the ED: comparison of surgical and nonsurgical residents.

The purpose of this study was to evaluate the impact of a surgery-based (SB) versus nonsurgery-based (NSB) training background of residents on the diagnosis of acute appendicitis in the emergency department (ED). The medical records of 641 adult patients who had undergone an appendectomy during a 3-year period (July 1996 to June 1999) were reviewed. All the patients were divided into NSB-in charge (n = 367) and SB-in charge (n = 274) groups, and demographic and clinical data recorded. Both groups' patients showed no differences in either negative appendectomy or perforation rates. However, NSB group patients had longer in-hospital delays in comparison with SB group patients (12.0 +/- 0.7 versus 9.6 +/- 0.4 hours, P <.05). This longer stay time mainly occurred in the patients with negative exploration and uncomplicated appendicitis P <.05). In both groups, patients with complicated appendicitis had longer prehospital delay of presentation than those with uncomplicated appendicitis. (2.0 +/- 0.2 versus 1.2 +/- 0.1 days in NSB group; 2.5 +/- 0.5 versus 1.3 +/- 0.2 days in SB group, P <.01). The NSB residents tended to order more computed tomography (CT) scans than SB residents (12% versus 5.1%, P <.05). With the application of a CT scan, the negative appendectomy rate was reduced significantly from 23% to 12%. We concluded that under the supervision of board-certified emergency physicians, the NSB residents had capabilities similar to SB residents in making correct diagnoses of acute appendicitis. In addition, close observation of equivocal cases in the ED did not necessarily increase the perforation rate.

Adult↗
PubMed2001

Amyloidosis-induced gastrointestinal bleeding in a patient with multiple myeloma.

We present a case of multiple myeloma (MM) complicated by recurrent amyloidosis-induced gastrointestinal bleeding. The patient presented with episodes of coffee-ground vomitus or massive hematochezia. No bleeding focus could be identified using endoscopy, a red blood cell scan, or angiography. Finally, a tissue biopsy taken at the irregular mucosa beside protruding vessels in the duodenum confirmed the diagnosis of gastrointestinal amyloidosis. As this case illustrates, the absence of systemic symptoms of amyloidosis and nonspecific endoscopic findings in gastrointestinal amyloidosis may make diagnosis difficult. Therefore, we recommend that a diagnosis of amyloidosis-induced gastrointestinal bleeding should be considered in patients with MM with an obscure hemorrhage.

Aged↗
PubMed2000

The effect of CNTF on glutamate-induced increases in intracellular free Ca2+ in hippocampal neurons.

Ciliary neurotrophic factor (CNTF) acts through the JAK/STAT signal transduction pathway. However, the rapid action of CNTF cannot readily be explained by reference to this pathway. Using the fluorophore, Fura 2-AM, and fluorescence imaging, the effect of CNTF on glutamate-induced increases in hippocampal intraneuronal free Ca2+ ([Ca2+]i) was investigated. Glutamate induces a rapid increase in [Ca2+]i. Incubation of hippocampal neurons with CNTF for 5 min inhibited the glutamate-induced increase in [Ca2+]i. In the absence of glutamate, CNTF had no effect on [Ca2+]i. Pertussis toxin (PTX), a G-protein antagonist, partially blocked the effect of CNTF. This suggests that CNTF may act via an alternative signal transduction pathway besides the generic JAK/STAT pathway.

Animals↗
PubMed2000

Chronic morphine treatment inhibits oxytocin synthesis in rats.

The changes of oxytocin content and mRNA expression in some nuclei were investigated in morphine-dependent rats using radioimmunoassay (RIA) and in situ hybridization (ISH). After chronic administration of morphine, the oxytocin content in supraoptic nucleus (SON) and nucleus accumbens (NAc) decreased, and increased in the ventral tegment area (VTA) and locus coeruleus (LC), but did not change in other nuclei including the paraventricular nucleus (PVN), lateral septum (SEPTUM), raphe magnus nucleus (NRM) and periaquaductal gray (PAG). In morphine-L dependent rats, naloxone increased the levels of oxytocin in SON and PVN, but decreased that in LC. ISH first showed that chronic morphine treatment inhibited the oxytocin synthesis in SON but not in PVN. The present study demonstrates that chronic morphine treatment alters the brain oxytocin system, suggesting that oxytocin might contribute to the behavioral and neuroendocrine responses to morphine.

Animals↗
PubMed2000

Distinct domains of IFNalpha mediate immune and analgesic effects respectively.

Interferon-alpha (IFNalpha) is not only an immunoregulatory factor, but is also an analgesic molecule. The analgesic effect of IFNalpha was mediated by mu opioid receptor. After the 129th Tyr residue of human IFNalpha was mutated to Ser, the antiviral activity almost disappeared, but there still remained a strong analgesic activity that could be blocked by naloxone. These results indicate that there exist distinct domains in the IFNalpha molecule, which mediate immune and analgesic effects respectively, and suggest that there are different receptor mechanisms inducing immune and analgesic effects of IFNalpha. However, although the antiviral activity of IFNalpha decreased to 34.1% of wild type IFNalpha after the 122nd Tyr residue was changed to Ser, the analgesic activity of this mutant was lost completely. There were significant cross reactivities between INFalpha and anti-opioid sera. These studies show strong structural and functional similarities between INFalpha and opioid peptides, and inferred that the analgesic domain locates around the 122nd Tyr residue of IFNalpha molecule in tertiary structure.

Amino Acid Substitution↗
PubMed2000

Preparation of recombinant human GDNF by baculovirus expression system and analysis of its biological activities.

Recombinant human glial cell line-derived neurotrophic factor (GDNF) has been expressed at high levels and produced in large quantities in baculovirus-infected Trichoplusia ni cells (Tn-5B1-4). The glycosylated protein was purified using immunoaffinity chromatography and gel filtration. Pure, recombinant human GDNF promoted the survival and morphological differentiation of embryonic dopaminergic neurons and enhanced axonal regeneration after sciatic nerve transection. Because recombinant bioactive human GDNF can be obtained in large quantities, and purified to near homogeneity, they are suitable for evaluation in animal models.

Animals↗
PubMed2000

Leu-enkephalin induced by IL-2 administration mediates analgesic effect of IL-2.

Interleukin-2 (IL-2) was found to have an analgesic effect in both central and peripheral nervous systems. This effect is related to opioid receptors and mediated mainly by IL-2 directly binding to opioid receptors. Using radioimmunoassay, the content of Leu-enkephalin (LEK) in some nuclei were measured at intervals after the injection of IL-2 into the lateral ventricle of rats. Levels of LEK increased in both paraventricular hypothalamic nucleus (PVN) and locus ceruleus (LOC) after IL-2 administration, suggesting that the analgesic effect of IL-2 is also related to the change of LEK in PVN and LOC induced by IL-2 administration.

Analgesics↗