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Biomedical subjects

J D Liu

Publications and source records attributed to J D Liu.

At least 37 records · Page 2Linked to original sources
PubMed1995

Congestive gastropathy in cirrhotic patients: correlation between endoscopic and histological findings.

Congestive gastropathy is a common cause of gastrointestinal bleeding in cirrhotic patients. Forty-six patients with cirrhosis of the liver and 225 control subjects matched in age and sex without cirrhosis of the liver entered the study. We studied the prevalence of congestive gastropathy in cirrhotic patients, and the relationship between endoscopic and histological findings. Congestive gastropathy seen endoscopically was found to be more common in the cirrhotic group than in the control (85% vs. 5%, P < 0.05). The sensitivity, specificity and positive predictive value were 85%, 95% and 76%, respectively. The presence of endoscopic congestive gastropathy was correlated with the severity of liver disease (P < 0.05), but not to the etiology of cirrhosis and the size of esophageal varices with or without red color sign. Endoscopic congestive gastropathy showed no correlation with the histological features including gastritis, interstitial edema, vessel ectasia/congestion and hemosiderin in endoscopic biopsy specimens. In conclusion, congestive gastropathy is a common finding in cirrhotic patients. Its appearance is closely correlated with the severity of liver disease. There is no good correlation between endoscopic congestive gastropathy and mucosal histology.

Adult↗
PubMed1995

Disseminated Penicillium marneffei infection in a patient with acquired immunodeficiency syndrome.

Penicillium marneffei is a rare human pathogen in Southeast Asia and Southern China. A 26-year-old heterosexual male had intermittent fever, diarrhea and weight loss for 3 months. He was severely immune deficient (CD4+ count, 4/microL) and serologic tests for antibodies against human immunodeficiency virus type-1 were positive. P. marneffei infection was disseminated with involvement of the liver, spleen and bone marrow. The diagnosis was established by histologic examination and confirmed by isolation of the fungus. This infection responded well to amphotericin B. He was discharged with maintenance therapy of itraconazole and continued to be stable during his 2-month follow-up.

AIDS-Related Opportunistic Infections↗
PubMed1995

Salmonella pericarditis and empyema: a case report.

A 54-year-old female diabetic patient who had been under regular oral hypoglycemic agent control for 2 years was admitted because of having dyspnea and orthopnea for several days. Massive pericardial effusion and a moderate amount of bilateral pleural effusion were noted at the time of admission. Pericardiocentesis and thoracocentesis were performed; both cultures grew Salmonella typhimurium. Antibiotic therapy was started immediately, but pleural effusion persisted. After repeated thoracocentesis and pleural effusion drainage, the patient was discharged 51 days later with complete recovery. Pericarditis and empyema are rare complications of Salmonella infections. Coexistence is even more rare, and only three cases have been reported in the English literature. Therefore, this case is presented with a review of the previous literature followed by discussion.

Empyema↗
PubMed1994

Carbon dioxide-enhanced ultrasonography of liver tumors.

CO2 gas-enhanced ultrasonography was performed in 37 patients (47 studies) for the purpose of detecting small tumors and evaluating differential diagnosis. With conventional ultrasonography, 62 lesions were identified in 25 patients with HCC, 13 tumors were identified in eight patients with hemangioma, and multiple tumors were found in four patients with metastatic adenocarcinoma. CO2-enhanced ultrasonography detected five additional hemangiomas, 12 additional nodules in HCC, and the same number of metastatic nodules. The patterns of CO2 enhancement were characterized as homogeneous, heterogeneous, rim, internal spotted, negative, and mixed (more than one pattern in one lesion). The rim enhancement pattern was found to be specific for hemangioma. The internal spotted enhancement pattern was found exclusively in HCC. All the lesions that demonstrated negative enhancement were treated HCC. All the metastatic tumors demonstrated the mixed rim and internal spotted enhancement pattern. We suggest that CO2-enhanced ultrasonography is a useful tool in detecting small liver tumors. It can also help in the differentiation among various hepatic tumors.

Adenocarcinoma↗
PubMed1993

Mutation analysis of K-ras oncogenes in gastroenterologic cancers by the amplified created restriction sites method.

A rapid, simple, and nonradioactive method for diagnosing point mutations of c-K-ras oncogenes in gastroenterologic cancers is described. This method involved the selective amplification of DNA fragments from cancer tissues of surgical specimens with specific oligonucleotide primers, followed by digestion with restriction enzymes that recognized artificially created or naturally occurring restriction sites. To detect codon 12 mutations, an artificial Msp I site was created by introducing a single nucleotide mismatch into the 5' mutagenesis primer. Using a similar approach, an Hae III site was created to detect codon 13 mutations. Bal I and MBo II sites were used to detect codon 61 mutations. A total of 61 gastroenterologic cancer cases were studied. Of 35 cases of colorectal cancer, 7 showed mutations: 6 at codon 12 and 1 at codon 13. In 1 of 2 cases of cholangiocellular carcinoma, point mutation at codon 12 was found. One case of duodenal cancer showed point mutation at codon 12. No mutations were found in the cases of hepatocellular carcinoma (4), gastric cancer (12), esophageal cancer (3), or pancreatic cancer (2).

Amino Acid Sequence↗
PubMed1993

Late-onset Lafora's disease with typical intraneuronal inclusions.

We describe a patient with progressive myoclonus epilepsy (late-onset Lafora's disease). Onset was in early adult life, and death was at age fifty-four. The initial symptoms were epileptic seizures and progressive dementia, with later occurrence of myoclonus. Lafora bodies were ubiquitous and in neuronal perikarya in many areas. Dust-like granular bodies predominated in the neuropil of cerebral cortex, substantia nigra, and striatum. Abnormal deposits were also found in the myocardium.

Brain↗
PubMed1991

Preparation of radioiodinated secretin for radioimmunoassay.

Radioiodination of synthetic human secretin on its N-terminal histidyl residue was not difficult when a greater amount of Chloramine T and a longer reaction time were employed to achieve better incorporation of 125I. The radioiodinated tracer for an optimal radioimmunoassay required purification. The combination of Sep-pak C18 Cartridge and high performance liquid chromatography for the purification of 125I-secretin in our study revealed that the Sep-pak cartridge was a preliminary step in removing unlabeled radioactive iodide, the reactant, and labeled materials unadsorbed to the cartridge. The eluate eluted from the Sep-pak containing high radioactivity and high immunoreactivity to the antibody were selected for further purification by HPLC which eliminated undesirable radiolabeled substances with lower immunoreactivity. The purified radiolabeled secretin was used in developing a sensitive radioimmunoassay.

Humans↗
PubMed1991

Genetic evidence for interaction between the CheW and Tsr proteins during chemoreceptor signaling by Escherichia coli.

This study presents two lines of genetic evidence consistent with the premise that CheW, a cytoplasmic component of the chemotactic signaling system of Escherichia coli, interacts directly with Tsr, the membrane-bound serine chemoreceptor. (i) We demonstrated phenotypic suppression between 10 missense mutant CheW proteins and six missense mutant Tsr proteins. Most of these mutant proteins had leaky chemotaxis defects and were partially dominant, implying relatively minor functional alterations. Their suppression pattern was allele specific, suggesting that the mutant proteins have compensatory conformational changes at sites of interactive contact. (ii) We isolated five partially dominant CheW mutations and found that four of them were similar or identical to the suppressible CheW mutant proteins. This implies that there are only a few ways in which CheW function can be altered to produce dominant defects and that dominance is mediated through interactions of CheW with Tsr. The amino acid replacements in these mutant proteins were inferred from their DNA sequence changes. The CheW mutations were located in five regularly spaced clusters in the first two-thirds of the protein. The Tsr mutations were located in a highly conserved region in the middle of the cytoplasmic signaling domain. The hydrophobic moments, overall hydrophobicities, and predicted secondary structures of the mutant segments were consistent with the possibility that they are located at the surface of the CheW and Tsr molecules and represent the contact sites between these two proteins.

Amino Acid Sequence↗
PubMed1990

Eosinophilic gastroenteritis with eosinophilic ascites: report of a case.

Eosinophilic gastroenteritis is a relatively uncommon disease of unknown etiology. Eosinophilic ascites resulting from significant serosal involvement is the rarest clinical subtype. The case reported here is of a 30-year-old male presenting with abdominal pain, diarrhea, and ascites. His personal history included childhood asthma, allergic rhinitis, and recurrent urticaria. The clinical picture was characterized by peripheral eosinophilia and eosinophilic infiltrates of the stomach and small bowel. Computed tomogram (CT) of the abdomen showed generalized thickening of the gastric and small bowel wall. Paracentesis revealed exudative ascites rich in eosinophils. The patient experienced an impressive response to steroid therapy.

Adult↗
PubMed1989

Subcellular distribution and immunocytochemical localization of protein kinase C in myocardium, and phosphorylation of troponin in isolated myocytes stimulated by isoproterenol or phorbol ester.

Protein kinase C (PKC) catalytic activity was found in the cytosol, sarcolemma and sarcoplasmic reticulum, and PKC immunoreactivity was found in the striated regions and sarcolemma of rat hearts. Enhanced phosphorylation of troponin T and, to a lesser extent, troponin I was noted in isolated rat cardiac myocytes incubated with PKC activator phorbol ester, but only the phosphorylation of troponin I was stimulated by isoproterenol. It is suggested that PKC-mediated phosphorylation of troponin might be involved in regulation of myocardial function or in pathophysiology of the heart.

Animals↗
PubMed1989

The human ATP synthase beta subunit gene: sequence analysis, chromosome assignment, and differential expression.

In humans, the functional F0F1-ATP synthase beta subunit gene is located on chromosome 12 in the p13----qter region. Other partially homologous sequences have been detected on chromosomes 2 and 17. The bona fide beta subunit gene has 10 exons encoding a leader peptide of 49 amino acids and a mature protein of 480 amino acids. Thirteen Alu family DNA repeats are found upstream from the gene and in four introns. The gene has four "CCAAT" sequences upstream and in close proximity to the transcriptional initiation site. A 13-bp motif is found in the 5' nontranscribed region of both the beta subunit gene and an ADP/ATP translocator gene that is expressed in high levels in cardiac and skeletal muscle. Analysis of the beta subunit mRNA levels reveals marked differences among tissues. The highest levels are found in heart, lower levels in skeletal muscle, and the lowest levels in liver and kidney. These findings suggest that the tissue-specific levels of ATP synthase beta subunit mRNA may be generated through transcriptional control.

Amino Acid Sequence↗
PubMed1989

Role of CheW protein in coupling membrane receptors to the intracellular signaling system of bacterial chemotaxis.

Chemotactic behavior in Escherichia coli is mediated by membrane-associated chemoreceptors that transmit sensory signals to the flagellar motors through an intracellular signaling system, which appears to involve a protein phosphorylation cascade. This study concerns the role of CheW, a cytoplasmic protein, in coupling methyl-accepting chemotaxis proteins (MCPs), the major class of membrane receptors, to the intracellular signaling system. Steady-state flagellar rotation behavior was examined in a series of strains with different combinations and relative amounts of CheW, MCPs, and other signaling components. At normal expression levels, CheW stimulated clockwise rotation, and receptors appeared to enhance this stimulatory effect. At high expression levels, MCPs inhibited clockwise rotation, and CheW appeared to augment this inhibitory effect. Since overexpression of CheW or MCP molecules had the same behavioral effect as their absence, chemoreceptors probably use CheW to modulate two distinct signals, one that stimulates and one that inhibits the intracellular phosphorylation cascade.

Bacterial Proteins↗
PubMed1989

Genetics and sequence analysis of the pcnB locus, an Escherichia coli gene involved in plasmid copy number control.

Mutations at the Escherichia coli pcnB locus reduce the copy number of ColE1-like plasmids. We isolated additional mutations in this gene and conducted a preliminary characterization of its product. F-prime elements carrying the pcnB region were constructed and used to show that the mutations were recessive. The wild-type pcnB gene was cloned into a low-copy-number plasmid, and its nucleotide sequence was determined. The sequence analysis indicated that pcnB is probably the first gene in an operon that contains one or more additional genes of unknown function. The pcnB locus should encode a polypeptide of 47,349 daltons (Da). A protein of this size was observed in minicells carrying a pcnB+ plasmid, and transposon insertions and deletions that truncated this protein generally abolished pcnB function. One exceptional transposon insertion at the promoter-distal end of the pcnB gene truncated the 47-kDa protein by about 20% but did not abolish complementation activity, indicating that the C-terminus of the PcnB product is dispensable. The deduced amino acid sequence of PcnB revealed numerous charged residues and, with 10% arginines, an overall basic character, suggesting that PcnB might interact with DNA or RNA in a structural capacity. Disruption of the pcnB gene by insertional mutagenesis caused a reduction in growth rate, indicating that PcnB has an important cellular function.

Amino Acid Sequence↗
PubMed1989

Infectivity in asymptomatic hepatitis B carriers: its correlation with HBeAg/anti-HBe status.

Sera collected from 190 asymptomatic HBsAg carriers with varying status of HBe markers were tested for HBV DNA using the slot-blot hybridization method and the results were compared with serum alanine aminotransferase (ALT) levels. No significant difference was observed in the positive rate of serum HBV DNA between patients showing either HBeAg (+)/normal ALT or HBeAg (+)/high ALT. On the other hand, in cases with positive anti-HBe or negative for both HBeAg and anti-HBe, statistically significant differences could be shown in HBV DNA positivity between normal and high ALT subjects. In the group of 100 patients possessing anti-HBe antibody, 50% of the cases with high ALT levels were positive for serum HBV DNA, whereas all of the cases with normal ALT levels were negative for serum HBV DNA (p less than 0.0002). In 21 patients showing HBeAg (-)/anti-HBe(-), HBV DNA could be detected in the serum of 60% of the cases with high ALT levels, but in none of the cases with normal ALT levels (p less than 0.05). Our results suggest that HBeAg alone is a reliable marker in the prediction of infectivity in asymptomatic carriers. In cases showing anti-HBe (+), loss of infectivity could be ascertained if the patient had normal serum ALT, but, continuous viral replication should be suspected in cases with high serum ALT values.

Adolescent↗