Is the graft too big or too small? Technical variations to overcome size incongruity in visceral organ transplantation.
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Adolescent↗
Biomedical subjects
P Liu
Publications and source records attributed to P Liu.
Kinetics of biodegradation of di-n-butyl phthalate in continuous culture system.
The characteristics of microbial growth and kinetics of DBP biodegradation was studied in a continuous culture system using DBP as a sole source of carbon. The results showed that, at high substrate concentration, the microbial growth was inhibited by DBP, and can be described by the Haldane model. Kinetic parameters based on Haldane substrate inhibition were evaluated. The values were mu(m) = 0.38 h-1, Ki = 86 mg/l, Ks = 28 mg/l. The DBP concentration to avoid substrate inhibition was inferred theoretically and determined to be 49 mg/L.
Biodegradation, Environmental↗
Bovine torovirus: sequencing of the structural genes and expression of the nucleocapsid protein of Breda virus.
Breda virus (BRV), a member of the genus torovirus, is an established etiological agent of diarrhea of cattle, which is found as two separate serotypes, BRV-1 and BRV-2. In this study, a 7.5 kb fragment of the BRV-1 genome that bracketed the genes for the structural proteins of BRV was amplified by long RT-PCR and the amplicon purified and sequenced directly. Sequence analysis revealed the presence of four open reading frames (ORF) corresponding to the peplomer (S), envelope (M), and nucleocapsid (N) genes, and an ORF for a novel 1.2 kb gene located between the M and N genes. This new gene was identical in nucleotide sequence to the hemagglutinin-esterase (HE) gene of BRV-2. With the exception of this new ORF, BRV-1 manifests 80% nucleotide sequence identity with the torovirus prototype, Berne virus (BEV) in the 7.5 kb region from the 3' end of the genome that contains the genes for the structural proteins. A 504 base segment containing the ORF for the BRV-1 N gene was amplified by RT-PCR, and cloned into an Escherichia coli expression system. The resulting protein was purified by SDS-PAGE and used to immunize guinea pigs. Hyperimmune serum was reactive with bovine torovirus (BTV) and human torovirus (HTV) antigens. By immunoelectron microscopy, it was shown to aggregate broken but not intact torovirus particles from BTV-positive fecal specimens. By immunoblot, the hyperimmune serum reacted specifically with the 20 kD N proteins of both BTV and HTV, as well as with the expressed N protein. BRV-1 and BRV-2 immune sera from gnotobiotic calves, but not human convalescent sera from HTV-infected patients, reacted with the expressed N protein by immunoblot. These findings were applied to the design of a dot blot assay that could specifically detect BTV and HTV from fecal specimens.
Amino Acid Sequence↗
Elevated concentrations of soluble intercellular adhesion molecule-1 were associated with increased risk of MI.
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Journal Article↗
Augmentation of nitric oxide, superoxide, and peroxynitrite production during cerebral ischemia and reperfusion in the rat.
The effect of ischemia produced by bilateral occlusion of the common carotid arteries (30 min) followed by 4 hours of reperfusion on total and inducible nitric oxide synthase (NOS) activity and the production of nitric oxide (NO), superoxide and peroxynitrite in the cerebral hemispheres was determined in the rat. Compared to sham-operated controls, cerebral ischemia-reperfusion resulted in a significant increase in total and inducible NOS activity and a significant increase in the production of NO and superoxide in the cerebral hemispheres. The level of NO in the plasma and the peripheral leukocyte count were also significantly increased. Immunohistochemical staining for nitrotyrosine (a marker of peroxynitrite production) showed that ischemia-reperfusion resulted in increased synthesis of cerebral peroxynitrite. Administration of the irreversible NOS inhibitor, Nomega-nitro-L-arginine (L-NA), increased superoxide levels in the brain and significantly reduced plasma NO. Total and inducible NOS activity as well as NO and immunoreactive nitrotyrosine, in the cerebral hemispheres were reduced with L-NA administration. The number of leukocytes in the plasma was unaffected by administration of L-NA. These findings suggest that cerebral ischemia-reperfusion causes increased production of reactive oxygen species in the cerebral hemispheres and that the production of peroxynitrite, and not superoxide, may be dependent upon the availability of NO.
Animals↗
Perirhinal cortex contributions to performance in the Morris water maze.
Rats with bilateral, electrolytic lesions of perirhinal cortex (PRC), lateral entorhinal cortex (LEC), or combined lesions (PRLE) were impaired relative to controls (sham) during initial acquisition in the Morris water maze, although all groups were eventually able to learn to locate the platform. A further deficit in the performance of PRC and PRLE, but not LEC groups, was evident, however, when a probe trial was conducted 2 min (but not 24 hours) after training. When the performance of sham- and PRC-lesioned rats was tested with variable memory delays inserted between training and probe trials, lesioned rats displayed an increase in the rate of forgetting for information made available during the training trial. This finding suggests that the PRC normally stores information regarding the cue-platform relationship and transfers this information to related structures during water maze performance.
Analysis of Variance↗
Excitotoxic lesions centered on perirhinal cortex produce delay-dependent deficits in a test of spatial memory.
Rats with bilateral electrolytic or ibotenic acid lesions that were centred in perirhinal cortex displayed a significant delay-dependent deficit on a delayed nonmatch to position task in the T maze. Although the removal of prominent extramaze visual cues did not affect the performance of these rats, rotating the maze between the sample and test phases did, indicating that rats were using a spatial strategy. Interestingly, a further group of rats with hippocampal and perirhinal damage displayed deficits that may reflect a dysfunction in the use of inertial cues. These results suggest that both electrolytic and excitotoxic lesions of perirhinal cortex produce spatial memory impairments but that these impairments are qualitatively different than those exhibited following hippocampal damage.
Analysis of Variance↗
A serine elastase inhibitor reduces inflammation and fibrosis and preserves cardiac function after experimentally-induced murine myocarditis.
In viral myocarditis, inflammation and destruction of cardiac myocytes leads to fibrosis, causing progressive impairment in cardiac function. Here we show the etiologic importance of serine elastase activity in the pathophysiology of acute viral myocarditis and the therapeutic efficacy of an elastase inhibitor. In DBA/2 mice inoculated with the encephalomyocarditis virus, a more than 150% increase in myocardial serine elastase activity is observed. This is suppressed by a selective serine elastase inhibitor, ZD0892, which is biologically effective after oral administration. Mice treated with this compound had little evidence of microvascular constriction and obstruction associated with myocarditis-induced ischemia reperfusion injury, much less inflammation and necrosis, only mild fibrosis and myocardial collagen deposition, and normal ventricular function, compared with the infected nontreated group.
Administration, Oral↗
The P-transform and photoacoustic image reconstruction.
Photoacoustic imaging is a new imaging modality which converts pressure signals received by an array of transducers to a regional distribution of electromagnetic absorption density. This paper presents a rigorous theory for photoacoustic image reconstruction in a concise format. A new type of transform, the P-transform, is proposed, analysed and presented as the main mathematical tool for reconstruction. It is proved that photoacoustic image reconstruction is intrinsically a three-dimensional (3D) procedure. The spatial smear function (SSF) is introduced. To complete photoacoustic image reconstruction an integral equation must be solved, which is replaced by a matrix approach in a discretized space. An example using synthetic data proves the validity of the photoacoustic image reconstruction theory proposed in the paper. The example shows that even the first-order approximation of photoacoustic image reconstruction gives good agreement with reality. It is also seen from the example that the accuracy and noise immunity of the reconstruction procedure depend on the experimental arrangement.
Acoustics↗
Proliferative activity in placentas with hydropic change and hydatidiform mole as detected by Ki-67 and proliferating cell nuclear antigen immunostaining.
Complete hydatidiform moles (CHM) and partial hydatidiform moles (PHM) represent different clinicopathologic entities. To obtain prognostic and therapeutic information about both entities, it is important that pathologic classification be as accurate as possible. The distinction of molar pregnancy and an abortus with hydropic changes (AHC) can sometimes be very difficult. The acquisition of 2 antibodies against nuclear antigens expressed in cycling cells, Ki-67 and proliferating cell nuclear antigen (PCNA), allow the study of trophoblastic proliferation in CHM, PHM, and AHC. The purpose of this study is to determine whether immunocytochemical stains can help in the distinction between those entities. All materials were obtained by curettage from 95 patients with hydropic villi evident on microscopic examination. The 95 cases included 33 cases of CHM, 42 cases of PHM, and 20 cases of AHC. In the case of the Ki-67 staining, the mean was much lower in the ACH group (8.7%) than in the PHM group (65.3%) or in the CHM group (84.6%). In the case of PCNA staining, the mean differences among the 3 groups (AHC, 23.1%; PHM, 80%; and CHM, 89.2%) were all statistically significant. On the basis of the means and the Gaussian results, it appears that the Ki-67 distribution gives a better separation among the 3 groups. In conclusion, proliferative activity is an additional useful parameter for evaluation of molar pregnancies and hydropic changes, with Ki-67 staining allowing better separation than PCNA staining does.
Cell Division↗
Embryonic lethality and tumorigenesis caused by segmental aneuploidy on mouse chromosome 11.
Chromosome engineering in mice enables the construction of models of human chromosomal diseases and provides key reagents for genetic studies. To begin to define functional information for a small portion of chromosome 11, deficiencies, duplications, and inversions were constructed in embryonic stem cells with sizes ranging from 1 Mb to 22 cM. Two deficiencies and three duplications were established in the mouse germline. Mice with a 1-Mb duplication developed corneal hyperplasia and thymic tumors, while two different 3- to 4-cM deficiencies were embryonically lethal in heterozygous mice. A duplication corresponding to one of these two deficiencies was able to rescue its haplolethality.
Aneuploidy↗
A new source of human oocytes: preliminary report on the identification and maturation of human preantral follicles from follicular aspirates.
This study aimed to investigate the development of human preantral follicles and oocyte maturation in vitro. Preantral follicles were obtained from follicular aspirates during egg retrieval carried out during an in-vitro fertilization (IVF) programme. They were first incubated in Ham's F10 medium with 15% fetal cord serum (FCS). After 28 days, the medium was supplemented with different doses of human menopausal gonadotrophin (HMG), human follicular fluid (hFF) and epidermal growth factor (EGF) by orthogonal design. Promotion of final maturation was completed in the presence of HMG and hFF. Development from preantral to antral follicles was found within 6-12 days of culture. With time, the proportion of follicles with diameters of >300 microm increased at 21-28 days of culture (P < 0.005). The maximum number of oocytes extruded, and first polar body formation, occurred in the presence of 0.15 IU/ml HMG 40% (v/v) hFF and 6 ng/ml EGF. We conclude that follicular aspirates obtained during egg retrieval in an IVF programme contain many preantral follicles which could develop into antral follicles with extrusion of oocytes in culture, and that the oocytes can mature in vitro. Hence, a new source of human oocytes is available.
Cell Differentiation↗
Chronic endothelin-1 blockade preserves myocardial contractility in dilated cardiomyopathy.
Endothelin-1 (ET-1) is known to have positive inotropic effects in isolated cardiac muscle strips. ET-1 levels are elevated in congestive heart failure (CHF). We investigated the effects of ET-1 on contractility and cardiac relaxation (lusitropy) of the intact healthy murine heart and myocarditic/cardiomyopathic heart by chronic oral treatment with a mixed ETA/ETB blocker SB217242. Chronic ET-1 blockade of normal hearts resulted in depression of contractility and lusitropy of the normal heart but preservation and enhancement of contractility and lusitropy in myocarditic animals, in which ET-1 cardiac content is elevated. This suggests that ET-1 is important in the basal contractility and relaxation of the normal heart but that its chronic elevation in CHF causes impairment of cardiac systolic and diastolic performance.
Animals↗
Uterine cervical dysplasia and cancer: identification of c-myc status by quantitative polymerase chain reaction.
The c-myc oncogene status was determined in patients with nondysplasia (ND; 9 patients), low-grade squamous intraepithelial lesion (LGSIL; 12 patients), high-grade squamous intraepithelial lesion (HGSIL; 21 patients) and invasive squamous cell carcinoma (ISCC; 20 patients) of uterine cervix using fluorescent quantitative polymerase chain reaction (PCR). In the same paraffin-embedded specimens, other potential risk factors were also screened: human papillomavirus (HPV) infection, Ha-ras codon 12 mutation, DNA aneuploidy. Gene amplification, identified as c-myc copy numbers greater than the mean value +2 SD of patients with ND, was seen in 44% patients with LGSIL, 76% patients with HGSIL, and 67% patients with ISCC. These data indicate that c-myc amplification is one of the critical early events in the progression of uterine cervical lesions. HPV infection of various subtypes was identified in 0% patients with ND, 55% patients with LGSIL, 95% patients with HGSIL, and 84% patients with ISCC. No codon 12 mutation of the Ha-ras gene was found in this series. Aneuploid DNA pattern was seen in 0% patients with ND, 58% patients with LGSIL, 90% patients with HGSIL, and 80% patients with ISCC. There was a significant correlation between HPV infection and DNA aneuploidy. However, no relationship was seen between c-myc status and other factors in this series. Patients with HGSIL and ISCC almost always (95%) had multiple risk factors, whereas more than half of the patients with LGSIL had no or only one risk factor (P = 0.0001).
Aneuploidy↗
Clinical psychopharmacology in China: the last decade.
Clinical psychopharmacological research has focused on several aspects in the last decade in China. First, attention was paid to new drug trials, mainly on newly developed or imported antidepressants or antipsychotics. More and more newly developed antidepressants like SSRI, fluoxetine, paroxetine, sertraline, and citalopram are now available or under clinical observation. Second, studies on the relationship between blood level and clinical response of antidepressants, amitriptyline, or antipsychotics, haloperidol and clozapine were undertaken. Results on amitriptyline showed that the clinical antidepressive effect of the drug was correlated linearly to the parent compound, amitriptyline, and curvilinearly to the hydroxylated metabolite, 10-hydroxynortryptyline. It was found that the plasma level of haloperidol correlated curvilinearly to the clinical antipsychotic effect on schizophrenics with a therapeutic window ranging between 4.2 and 20 ng/mL. Third, pharmacokinetic studies on antidepressants, amitriptyline, imipramine, and maprotiline were undertaken. The results showed longer clearance rate and/or t(1/2) in Chinese literature than those reported in Western literature.
China↗
Sequence variation in the small-subunit rRNA gene of Plasmodium malariae and prevalence of isolates with the variant sequence in Sichuan, China.
By two PCR-based diagnostic methods, Plasmodium malariae infections have been rediscovered at two foci in the Sichuan province of China, a region where no cases of P. malariae have been officially reported for the last 2 decades. In addition, a variant form of P. malariae which has a deletion of 19 bp and seven substitutions of base pairs in the target sequence of the small-subunit (SSU) rRNA gene was detected with high frequency. Alignment analysis of Plasmodium sp. SSU rRNA gene sequences revealed that the 5' region of the variant sequence is identical to that of P. vivax or P. knowlesi and its 3' region is identical to that of P. malariae. The same sequence variations were also found in P. malariae isolates collected along the Thai-Myanmar border, suggesting a wide distribution of this variant form from southern China to Southeast Asia.
Animals↗
Identification of a negative cis element within the ZII domain of the Epstein-Barr virus lytic switch BZLF1 gene promoter.
The Epstein-Barr virus (EBV) lytic switch gene, BZLF1, is tightly regulated in latently infected B cells. The BZLF1 gene promoter (Zp) contains several cis elements that have been previously shown to respond to inducers of the viral lytic cycle. These include four copies of an element referred to as the ZI domains and an element that contains a consensus CRE/AP-1 motif (ZII domain). In addition, Zp is autoregulated through two sites that bind the BZLF1 gene product Zta. The ZI domains have been shown to bind the ubiquitous cellular transcription factors Sp1 and Sp3 and/or the myocyte enhancer factor 2D (Liu et al., EMBO J. 16:143-153, 1997; Liu et al., Virology 228:9-16, 1997). Here we present a functional analysis of the ZII domain and show: (i) ATF-1 and ATF-2 appear to be the predominant cellular factors that bind to the CRE/AP-1 motif present in the ZII domain; and (ii) the region immediately upstream of the CRE/AP-1 motif contains a potent negative cis element, mutation of which results in a >10-fold increase in Zp activity. The negative cis element (ZIIR) in the ZII domain decreases both basal and induced Zp activity and thus is likely to play an important role in regulating reactivation of EBV. In addition, analysis of heterologous promoter constructs indicates that the function of ZIIR is context sensitive. Attempts to demonstrate a cellular factor binding to ZIIR have been unsuccessful, leaving unresolved the mechanism by which repression is mediated.
Activating Transcription Factor 1↗
NO modulates P-selectin and ICAM-1 mRNA expression and hemodynamic alterations in hepatic I/R.
The anti-inflammatory role of nitric oxide (NO) was studied in a model of hepatic ischemia-reperfusion (I/R) in rats. Male Fischer rats were subjected to 30 min of no-flow ischemia of the left and median lobes of the liver, and animals were examined for a 4-h period of reperfusion. The animals were divided into the following groups: control-vehicle; I/R-vehicle; I/R-Nomega-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg iv, 10 min before reperfusion); sham control-L-NAME, and I/R-S-nitroso-N-acetyl-penicillamine (SNAP, 25 micromol/kg iv, 10 min before reperfusion, followed by 20 micromol. kg-1. h-1 in 1.0 ml saline infused for 4 h). Results showed that mean arterial blood pressure was significantly increased in the sham control-L-NAME or I/R-L-NAME groups compared with either the I/R-vehicle or I/R-SNAP groups. However, cardiac index (CI) and stroke volume index (SVI) were markedly decreased, and systemic vascular resistance index (SVRI) was dramatically increased. Interestingly, the CI and SVI in rats treated with SNAP were markedly improved over that of the I/R group. Plasma nitrate and nitrite levels were significantly decreased in the I/R-L-NAME group; however, superoxide generation in the ischemic lobes and plasma alanine aminotransferase activity were higher compared with I/R-SNAP rats. The L-NAME-induced enhancement of hepatic injury in rats with I/R may be due in part to neutrophil infiltration, which was significantly increased compared with animals subjected to I/R or I/R-SNAP. The mechanism of L-NAME-enhanced neutrophil infiltration may be due to the fact that the ratios of P-selectin and intercellular adhesion molecule 1 (ICAM-1) mRNA to glyceraldehyde-3-phosphate dehydrogenase mRNA extracted from the ischemic lobes of I/R-L-NAME rats were significantly increased when compared with the I/R-SNAP group. These results suggest that 1) endogenous NO reduces the SVRI and permits an increased CI and SVI; 2) exogenous NO further improves CI and SVI; and 3) endogenous, but not exogenous, NO decreases P-selectin and ICAM-1 mRNA expression, thereby reducing polymorphonuclear neutrophil-dependent reperfusion tissue injury.
Alanine Transaminase↗