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Y W Li

Publications and source records attributed to Y W Li.

At least 19 recordsLinked to original sources
PubMed2000

Morphological and electrophysiological properties of neurones in the dorsal vagal complex of the rat activated by arterial baroreceptors.

This study physiologically identifies and anatomically describes arterial baroreceptive neurones in the nucleus tractus solitarii of the rat. Neurones were recorded using neurobiotin-containing whole cell patch electrodes in a working heart-brainstem preparation and characterized physiologically as arterial baroreceptive in response to stimulation of the aortic arch and/or ipsilateral carotid sinus. Fifteen of 84 neurones tested were arterial baroreceptive, 7 of 8 were morphologically identified as located in the solitary tract nucleus (NTS), and 1 of 8 was located in the dorsal vagal nucleus. The seven NTS neurones had a resting membrane potential of -52 +/- 3.6 mV and a membrane input resistance of 233 +/- 38 M omega. Action potential height was 62 +/- 4.2 mV, width at half amplitude 1.46 +/- 0.38 ms, and duration of after-hyperpolarization 1.7 +/- 2.33 ms. In six of eight neurones labelled there was an invariant excitatory synaptic input (latency 3.95 +/- 0.3 ms) to stimulation of the solitary tract. Labelled somata were dorsomedial or medial to the solitary tract from -0.3 mm to +1.5 mm with regard to obex. Neurones had three to eight primary dendrites, and branches often entered the solitary tract and also extended across the ipsilateral NTS. Axons, which were mostly unmyelinated with boutons of the en passant variety, could ramify within the NTS while the main axon exited the NTS (n = 4/6), in the direction of the ipsilateral ventral medulla (n = 5/6). This is the first morphological and localisation data of physiologically characterised arterial baroreceptive NTS neurones in the rat. By comparing labelled cells with each other as well as with other unidentified cells, we conclude that NTS arterially baroreceptive neurones are morphologically and physiologically heterogenous.

Animals↗
PubMed2000

Right lung agenesis with left pulmonary artery sling.

We report on a 2-month-old infant girl who had right pulmonary agenesis and an unusual course of the left pulmonary artery. Computed tomography and cardiac catheterization showed that the left pulmonary artery arose from the main pulmonary artery, crossing the midline, and reaching the left lung via an aberrant course between the esophagus and trachea. The coexistence of right pulmonary agenesis and left pulmonary sling is extremely rare. Unlike in other reports, our patient remained symptom-free and in good health, with normal growth and development until age 2 years, when she died from complications during an attack of bronchiolitis caused by respiratory syncytial virus.

Bronchiolitis↗
PubMed2000

A novel injectable bioactive bone cement for spinal surgery: a developmental and preclinical study.

The injection of bone cement by minimally invasive techniques for the treatment of vertebral body fractures or for stabilization of an osteoporotic vertebral body is regarded as promising in spinal surgery. The purpose of this study was to develop a novel injectable bioactive bone cement to address such concerns. The cement was composed mainly of strontium-containing hydroxyapatite (Sr-HA) filler and Bisphenol A Diglycidylether Dimethacrylate (D-GMA) resin. The Sr-HA filler was prepared by precipitation and calcination, then analyzed with Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) patterns. Samples of strontium-containing hydroxyapatite cement (SrHAC) were formed by a combination of powder filler and resin matrix, with the setting time and peak temperature recorded. Cell relative growth rate (RGR), Tetrazolium bromide (MTT), and haemolysis tests were used to detect initial in vitro biocompatibility of the new cement. In vitro spinal biomechanical testing and morphological observation after bone cement injection were performed on pig spines. Results indicate that the setting time and peak temperature of the cement was 15 min and 55 degrees C, respectively. Cytotoxicity of the cement was class 1 (no cytotoxicity) and haemolysis was 1% (no haemolysis). Stiffness after cement injection and fatigue loading were 112% and 95% of the intact bone, respectively, which is similar to that of natural bone. Radiopacity of SrHAC allowed easy radiographic imaging. The use of SrHAC cement is, thus, promising in spinal surgery.

Animals↗
PubMed2000

Properties of solitary tract neurons receiving inputs from the sub-diaphragmatic vagus nerve.

Vagal afferents ascending from the gastrointestinal tract synapse on neurons in the nucleus of the solitary tract. Although these neurons constitute a significant proportion of solitary tract cells their firing behaviour and synaptic properties are not documented. Since gastrointestinal tract afferent termination sites overlap with regions mediating cardiorespiratory reflexes the possibility of convergence with afferents mediating cardiovascular and respiratory reflexes was proposed. Here we describe some electrophysiological and morphological properties of solitary tract neurons orthodromically driven from the subdiaphragmatic vagus nerves and assess possible convergent inputs from cardiorespiratory afferents. Whole-cell recordings of solitary tract neurons responding to electrical stimulation of the sub-diaphragmatic vagus nerves (0.1-1 ms; 1-10 V; 2-20 Hz) were made in a working heart-brainstem preparation of rat. Baroreceptors were stimulated by raising pressure in the aorta or carotid sinus, whereas aortic injection of sodium cyanide (0.05% solution 25-50 microl) was used to activate peripheral chemoreceptors. Phrenic nerve activity and heart rate were monitored continuously. Of 88 solitary tract neurons tested, 39 responded with an evoked excitatory synaptic potential following stimulation of the sub-diaphragmatic vagus nerves. Resting membrane potential and input resistance of sub-diaphragmatic vagus nerve driven solitary tract neurons were 53.2 +/- 0.5 mV and 291 +/- 17 Mohms, respectively (mean +/- S.E.M.). Response latencies to sub-diaphragmatic vagus nerve stimulation were divided into two groups: <20 ms (16.0 +/- 2 ms, n = 7; mean +/- S.E.M.) and >20 ms (77.3 +/- 5 ms, n = 32). One additional neuron displayed an evoked inhibitory postsynaptic potential (latency 175 ms). Nineteen neurons showed ongoing activity which consisted of either irregular single action potential firing (0.5-10 Hz; n = 12) or burst discharge (n = 7). Of 33 neurons tested, 17 showed spike frequency adaptation during injection of positive current, whereas 19 of 38 cells displayed rebound excitation following release from hyperpolarized potentials. There was no correlation between these properties and synaptic latencies. Ninety-one per cent of neurons tested displayed synaptic depression following paired pulse stimulation of the sub-diaphragmatic vagus nerve over intervals up to 500 ms. Stimulation of either baroreceptors (n = 31) or chemoreceptors (n = 36) failed to elicit a synaptic response in all sub-diaphragmatic vagus nerve-driven solitary tract neurons. Neurobiotin-labelled solitary tract neurons (n = 10) were from both latency groups and were located medial to the solitary tract at the level of area postrema, -0.3 mm to +1 mm from the obex. One cell was located in commissural subnucleus at midline, seven cells dorsal to the tractus solitarius and three ventral and medial to it. Soma sizes were 23 +/- 9.6 x 14 +/- 4.9 microm (range: 50 x 16 microm to 15 x 7 microm). The number of primary dendrites varied from three to five, secondary from one to eight and tertiary zero to four. Labelled axons were found in seven cells which ramified extensively in the solitary tract nucleus (n = 3) and/or branched extensively in the dorsal vagal motonucleus (n = 3) and/or projected towards the ventrolateral medulla (n = 3). We conclude that solitary tract neurons receiving signals from the sub-diaphragmatic vagus nerves (most likely from gastrointestinal tract structures) appear to be a distinct pool of neurons. There was a heterogeneity in terms of both their ongoing activity and projection targets but despite this, there were three consistent properties. First, sub-diaphragmatic vagus nerve evoked predominantly excitatory synaptic responses in solitary tract neurons; second, neurons exhibited lasting paired pulse depression following activation of sub-diaphragmatic vagus nerves; and third, sub-diaphragmatic vagus nerve-driven solitary tract neurons were

Afferent Pathways↗
PubMed2000

Esophageal varices in congenital heart disease with total anomalous pulmonary venous connection.

Total anomalous pulmonary venous connection (TAPVC) is an uncommon congenital anomaly in which the anatomical presentations vary widely among patients. We hereby present two newborns with TAPVC associated with asplenia syndrome; both had severe esophageal varices due to infradiaphragmatic pulmonary venous drainage. Ultrafast computed tomography (CT) scanning was superior to color Doppler echocardiography and cardiac catheterization as it provided a detailed portrait of the pulmonary drainage. The remarkable radiographic manifestations are presented.

Cardiac Catheterization↗
PubMed2000

Anatomical studies of the urethral plate: why preservation of the urethral plate is important in hypospadias repair.

OBJECTIVE: To describe the detailed anatomy of the urethral plate in relation to its controversial role in hypospadias surgery. MATERIALS AND METHODS: A newborn penis with proximal penile hypospadias and two fetal penises with distal shaft hypospadias were included in the study; 30 normal fetal penises served as the control. Specimens were embedded in paraffin and serially sectioned (6 microm) after formalin fixation. Every 10th section was stained with haematoxylin and eosin. Immunohistochemical staining for nerves (S100), smooth muscles (alpha-actin), blood vessels (factor VIII) and epithelium (cytokeratins 7, 14 and 18) were used on selected sections, with particular attention to the urethral plate. Masson's trichrome and Sirius Red stains were used to localize collagen. RESULTS: There were extensive blood vessels, glands and smooth muscle under the urethral plate in the hypospadias specimens. These relatively well organized tissues corresponded to an abnormally formed corpus spongiosum. The glands underneath the urethral plate and adjacent to the normal urethra showed positive staining for cytokeratins 7 and 18, respectively (markers of endodermal origin) but were negative for cytokeratin 14 (a marker of ectodermal origin). Penile skin and urethral plate epithelium stained positively for cytokeratin 14 but not for cytokeratin 7 and 18. The urethral plate has a rich nerve supply, as determined by S100 staining. Collagen intensity under the urethral plate was no different from that in normal areas. Tunica albuginea stained intensely for type I and III collagen. CONCLUSION: These results show that the urethral plate is well vascularized, has a rich nerve supply and an extensive muscular and connective tissue backing. These features may explain the lower complication rate with onlay flaps than with tube flaps. Therefore, from these anatomical findings, we continue to advocate preservation of the urethral plate and the onlay island flap for hypospadias reconstruction.

Case-Control Studies↗
PubMed2000

Anatomy of the neurovascular bundle: is safe mobilization possible?

PURPOSE: We have previously defined the anatomy of the neurovascular bundle in the normal and hypospadiac penis. Historical experience suggests that mobilization of the neurovascular bundle is anatomically possible. We attempt to prove whether mobilization of the neurovascular bundle is safe and theoretically sound. Specific questions that will be addressed are does the neurovascular bundle send perforating branches into the corporal bodies; how far lateral does the dissection need to be before nerves are injured and exactly how deep into Buck's fascia must one go. MATERIALS AND METHODS: A total of 35 normal human fetal penile specimens, gestational age 8 to 35 weeks, and 3 hypospadiac specimens, 33 to 41 weeks of gestation, were serially sectioned and stained with Mason's trichrome and the neuronal markers PGP 9.5 or S100. Computer reconstruction using commercial software and National Institutes of Health imaging allowed 3-dimensional analysis of the nerves, corporal bodies and glans. RESULTS: Perforating nerves into the erectile bodies were not documented along the dorsal or lateral aspect of the tunica in any of the specimens studied. Only in the area of the crural bodies on the ventral lateral surface were nerves noted to pierce into erectile tissue. The neural network was extensive from the 11 and 1 to the 5 and 7 o'clock positions corresponding to the erectile tissue and urethral spongiosum junction. At this junction minor nerve branches were noted to perforate into the urethral spongiosum. A microscopic plane exists between the neurovascular bundle and tunica of the corporal bodies measuring 20 to 30 micro. in specimens greater than 30 weeks in gestation. CONCLUSIONS: Perforating branches from the dorsal lateral neurovascular bundle do not exist based on serial step sectioning and microscopic examination of male genital specimens. Surgically it is possible to elevate the neurovascular bundle but the dissection needs to remain directly on top of the tunica albuginea to prevent neuronal injury. Small perforating branches into the urethral spongiosum may be injured with unknown significance. We continue to advocate plication in the nerve-free zone at the 12 o'clock position for correction of penile curvature.

Fetus↗
PubMed2000

Molecular cytogenetic analysis of intergeneric chromosomal translocations between wheat (Triticum aestivum L.) and Dasypyrum villosum arising from tissue culture.

Fluorescence in situ hybridization (FISH) was applied with total genomic DNA extracted from Dasypyrum villosum (L.) Candargy as a probe to characterize chromosome translocations arising from tissue culture in hybrids of Triticum aestivum x (T. durum - D. villosum, amphiploid). Chromosome translocations between wheat and D. villosum occurred in callus cells at an average frequency of 1.9%. Translocations existed not only in callus cells but also in regenerants. Three plants with translocation chromosomes were characterized among 66 regenerants of T. aestivum 'Chinese Spring' x 'TH1W' and 'NPFP' x 'TH1'. One of them proved to be a reciprocal translocation with an exchange of about one third of a wheat chromosome arm with about one half of a chromosome arm of D. villosum. The breakpoints of the other two translocations were located at, or near centromeres. The results are similar for both callus cells and regenerants and provide further evidence that translocations take place in tissue culture. Other structural chromosomal changes, for example, fragments, telocentrics, dicentromeres, and deletions, as well as numerical alterations including aneuploidy and polyploidy were recorded both in callus cells and regenerants.

Animals↗
PubMed2000

The preoperative and postoperative cerebral blood flow and vasoreactivity in childhood moyamoya disease.

PURPOSE: To report the hemodynamic pattern in childhood moyamoya disease before and after vascular reconstruction. METHODS: We performed the xenon cerebral blood flow (CBF) study in 10 cases of moyamoya disease in last 3 year. In 6 of them, study before and after operation was obtained for comparison. Preoperative study was obtained in 2 cases and postoperative study was obtained in 2 cases. They were 5 males and 5 females with age ranging from 1 to 12 years old. We studied their regional CBF before and after acetazolamide (CCBF) using stable xenon computed tomography. The angiography study was obtained for comparison. RESULT: In the routine study, the CBF and CCBF were poor in the ACA and MCA territory and well correlated to the angiography finding. However, in case of basal ganglion and posterior cerebral artery involvement, xenon CBF study was more sensitive than the angiography. On the postoperative cases, the CBF could increase to a level beyond the level of CCBF shown on the preoperative study. CONCLUSION: Hemodynamic study using stable xenon computed tomography can provide an objective reference for the treatment of moyamoya disease especially in case that surgical management is considered. It is a better modality for the evaluation of surgical outcome than the conventional contrast angiography study.

Acetazolamide↗
PubMed2000

[Estimation of biolistic transformation effect by transient expression of C1-R regulatory genes of anthocyanin biosynthesis].

In the present study, the transient expression of maize C1-R regulatory genes of anthocyanin biosynthesis in maize calli, wheat immature embryos, rice calli and tobacco leaves were described. C1-R regulatory genes could activate anthocyanin biosynthesis in vivo and the pigmented cells were visible. For major crops, including maize, wheat and rice, which were transformed mainly by biolistic method, C1-R genes were novel visible markers, and the expression was easier to detect than GUS gene. And these genes also worked well in transient expression in biolistic transformation system of tobacco leaves.

Anthocyanins↗
PubMed2000

[Tissue culture induced translocation conferring powdery mildew resistance between wheat and Dasypyrum villosum and its marker-assisted selection].

Glutamate oxaloacetate transaminase (GOT) electrophoretic analyses were performed in 175 regenerants arising from immature embryos of crosses between wheat (Triticum aestivum L.) and 6D/6V substitution stocks. The GOT-V2 coding specific enzyme band was absent in two regenerants, designated 98R149 and 98R159 respectively, originated from cross of Yi 4095 and 6D/6V substitution stock c.v. RW15. Pm21 gene linked SCARs (Sequence Characterized Amplified Regions) analysis indicated that 6VS chromosome arms existed in 98R149 and 98R159. Fluorescence in situ hybridization with total genomic DNA extracted from Dasypyrum villosum (L.) as a probe confirmed the occurrence of translocation between 6V chromosome and a wheat one in the two regenerants mentioned above. 98R149 and 98R159 were immune to powdery mildew (Erysiphe graminisDC. f. sp. tritici) inoculation with mix races collected from Hebei Province. The results of the present paper added another feasible example of useful translocations via tissue culture.

Aspartate Aminotransferases↗
PubMed2000

[High efficient intergeneric chromosomal translocations between wheat (Triticum aestivum L.) and Dasypyrum villosum arising from tissue culture and irradiation].

Intergeneric chromosomal translocations were discernable both in callus cells and in regenerants arising from crosses between Triticum aestivum and T. durum-Dasypyrum villosum amphiploid c.v. TH1 and TH1W by means of fluorescence in situ hybridization. There were not only reciprocal translocations, but small fragment translocations. The results proved again the feasibility of creating intergeneric translocations via tissue culture. Irradiation facilitated numerical and structural chromosome changes in callus cells. The frequency of translocations was as high as 7.4 percent in irradiated callus cells. Callus age had an important impact on numerical and structural chromosome abnormalities. During a given time of culture, the frequency of unchanged cells was declined, while those cells with chromosome losses were inclined. The duration of culture had not significant effects on cells with chromosome gains. As structural chromosome changes is concerned, the duration of culture predominantly increased the frequency of cells with telocentric chromosomes. The chromosomal changes occurred at the initiation period of tissue culture. A number of cells which were doubled their chromosome numbers (2n = 84) were observed at a certain frequency in the period of tissue culture. These cells, however, disappeared in the successive culture.

Crosses, Genetic↗
PubMed2000

[The genetic behavior of an Agropyron intermedium chromosome conferring BYDV resistance in wheat background].

Based on the chromosome origin identification of an Agropyron intermedium chromosome with BYDV resistance in Yi4212, a BYDV-resistant substitution line derived from the hybrids between 77-5433 and Zhong5, its ability compensating the lost wheat chromosomes and its transmission rate were investigated. The results indicated that the BYDV-resistant chromosomes originated from Zhong 5 could compensate the wheat chromosomes of homotologous group 2, 5 and 7. The chromosome conferring resistance to BYDV showed the intendance to substitute 2D rather than 2A, 2B wheat chromosomes in disomic substitution lines. In (77-5433/Zhong 5) selfing F2 population, 10 kinds of chromosome constitutions, including 9 expected and 1 unexpected kinds, and much chromosome number variation and little chromosome structure variation were observed. The transmission rate of the BYDV-resistant chromosome and the gametes carrying this chromosome were 56.3% and 33.0% respectively, both are lower than the expected ratio 75.0% and 50.0%. Some reasons were given to explain the related results, and chromosome in situ hybridization was an efficient and accurate way in studying the alien chromosome behavior in wheat background.

Chromosomes↗
PubMed2000

[Fluorescence in situ hybridization applied to the meiotic analysis and spontaneous chromosome translocation in the pollen mother cells of hybrids of Triticum-Haynaldia].

Fluorescence in situ hybridization was applied to the meiotic analysis and chromosome pairing in the pollen mother cells of hybrids of Triticum-Haynaldia. The results indicated that most (90.5%-93.2%) of the PMCs of two Triticum-Haynaldia hybrids contained two univalents involving one Haynaldia chromosome at metaphase I, and only 1 of 320 PMCs with homologous pairing between one wheat chromosome and one Haynaldia chromosome was observed in the hybrid of Guinong 22 x common wheat Chinese Spring, the frequency was 0.3%. The frequencies of the PMCs with mis-dividing chromosome ranged from 32.7% to 37.5% at anaphase I and from 20.5% to 24.4% at anaphase II in the hybrids between Triticum-Haynaldia. The frequency of Haynaldia chromatin translocating into Triticum chromosome was about 0.7% at anaphase I in the hybrid of Guinong 22 x common wheat Chinese Spring and was 0.8%-1.7% at anaphase II in two wheat-Haynaldia hybrids. Otherwise, the chromosome morphology involving Haynaldia chromatin was observed at preleptotene I, and the frequencies of chromatin nucleus at tetrad stage and at microspore stage were investigated. The time of chromosome translocation in meiosis and the transmitting frequencies of Haynaldia chromosome in wheat background were discussed.

Gene Frequency↗
PubMed1999

Functional characterization of a purified, recombinant NF-kappaB/IkappaB complex.

The NF-kappaB signal transduction pathway involves the interaction of several NF-kappaB and IkappaB family members that are activated by a diverse range of extracellular signals and that stimulate many different cellular responses. The biochemical regulation of this cascade can be studied by establishing a cell-free system using purified proteins. As a first step toward establishing an in vitro model incorporating multiple combinations of NF-kappaB and IkappaB proteins, we produced purified human p65 (RelA) and human IkappaBalpha proteins and tested their functionality. Full-length RelA and IkappaBalpha proteins were overproduced by coinfection of TN5-JE cells with two recombinant baculoviruses. RelA and IkappaBalpha formed a stable complex that could be purified to >95% homogeneity. Protein-protein interactions, protein-DNA binding, and protein phosphorylation were similar to the native proteins.

Animals↗
PubMed1999

Regression of ductus arteriosus aneurysm in a neonate demonstrated by three-dimensional computed tomography.

We present a case of ductus arteriosus aneurysm in a neonate in whom the diagnosis was made by echocardiography, three-dimensional surface rendering computed tomography (CT) and was subsequently confirmed by angiography. Regression of aneurysm after indomethacin treatment was clearly demonstrated in a follow-up CT scan. To our knowledge, this is the first report of ductus arteriosus aneurysm and its regression detected by 3D surface rendering CT.

Aneurysm↗
PubMed1999

Solitary vertebral collapse: distinction between benign and malignant causes using MR patterns.

Differentiation of benign from malignant causes of vertebral compression fracture can be difficult at a single location. We studied 37 patients with solitary vertebral collapse (SVC) in the spine using magnetic resonance imaging (MRI). Sixteen of them were found to have a benign cause of SVC, while the remaining 21 were found to have malignancy. The following four MRI characteristics were investigated: ill- or well-defined margin of the intravertebral lesion (P < 0.005); pedicle involvement (P < 0.05); MR enhancement pattern (P < 0.005); and paravertebral soft tissue lesion (PSL) (P < 0.025). It was found that cases of malignant SVC tended to have an ill-defined margin, abnormal signal involvement of the pedicle, a marked and heterogenous MR enhancement pattern, and irregular nodular-type PSL. Pedicle change with expansile lesion totally excluded a benign cause. By using these criteria, we were able to differentiate benign or malignant causes of SVC accurately.

Aged↗