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Biomedical subjects

P He

Publications and source records attributed to P He.

At least 109 records · Page 6Linked to original sources
PubMed1997

Polymorphism of short tandem repeat (STR) loci PLA2, D3S2459, D8S315 (kw38), CYP19, D3S1359, FGA, and D8S1132 in the Japanese and Chinese populations.

We report a study of polymorphism for seven short tandem repeat (STR) loci in Japanese and Chinese populations. Among 104 to 134 individuals in the both population samples, eight alleles were revealed for locus PLA2, thirteen for D3S1359, eleven for FGA, eight for D8S315 (kw38), ten for D8S1132, five for CYP19, and seven for D3S2459. They correspondingly constituted 10 to 39 genotypes therein. For most of the STRs, there was only a single allele active as the most frequent one among the others, except locus D3S1359 in Chinese samples (two alleles, 206 bp and 210 bp, frequency = 0.273 each). Also, the population genotype configurations were locus specific, varying in the patterns of commonest genotypes on each locus, e.g., one pattern for loci CYP19, D3S1359, and D8S315, one and two for loci PLA2 and D3S2459, two for locus D8S1132, and one and four for locus FGA. The distributions of observed genotypes were in Hardy-Weinberg Equilibrium. Furthermore, the seven STRs were exhibited highly polymorphic and informative for the both populations, and the alleles could be easily separated in electrophoresis and correctly interpreted with side-to-side allelic ladders. Together, the results suggest that the tri- and tetra-meric STRs are useful genetic markers for forensic practice.

Alleles↗
PubMed1997

[Application of stochastical analysis to maternity testing without putative mother].

In a maternity test in which the putative mother was deceased, the cumulative probability of maternity (PM) was calculated at 0.822 from 24 genetic markers by the stochastical method. This PM may not be evaluated in the same way as that of usual paternity cases. We applied the same method to two families whose blood relationships were undoubted. We compared the PMs in the cases in which maternal genotypes were estimated and were defined. Also, we calculated the PMs in the case of real maternal relationship and false maternal one. The estimated PM from real maternity relationship was significantly higher than that from false maternal one.

ABO Blood-Group System↗
PubMed1997

3-D imaging of residual limbs using ultrasound.

In this article, a method of using ultrasound to image a residual limb is presented. The method employs a compound scanning technique to reconstruct a cross-sectional image (a slice) of the limb in a transverse plane. By scanning the limb in many transverse planes, a three-dimensional (3-D) volumetric image can be obtained from which either a transverse slice, a longitudinal cross section, or a 3-D surface of the limb can be displayed. The compound process circumvents the problems associated with the large attenuation of bones and enables reconstruction of a complete image of bones and adjoining tissues. In addition, the compound process improves the lateral resolution and reduces the speckle noise. Results obtained from a pair of thin wires, a contrast-resolution phantom, and a human limb demonstrate the beneficial effects of the compound process. To maximize the benefits, however, an accurate pixel registration in image reconstruction is essential. Sources of pixel misregistration and the potential means of minimizing misregistration are discussed.

Amputation Stumps↗
PubMed1997

Hardware and software considerations in 3D ultrasound imaging of a residual limb.

An ultrasound scan and data acquisition system has been developed for computer-aided prosthetic socket design. The system performs compound scan at each level of the limb by rotating an ultrasound probe around the limb to acquire 36 B-scan images. From these B-scan images, a transverse cross section of the limb is reconstructed using a spatial compounding algorithm. By scanning the limb at many levels, a 3D limb model can be reconstructed. The compound process circumvents the problems associated with the large attenuation of bones and enables reconstruction of a complete image of bones and adjoining soft tissues. In addition, the compound process reduces ultrasound speckle and improves the image quality. These benefits however, can only be achieved through careful hardware and software design. In this paper, methods and algorithms for system calibration, fast and accurate compounding, and removal of the artifacts caused by limb movement during scan are discussed.

Amputation Stumps↗
PubMed1996

Magnetic and electrical brain responses to chromatic contrast in human.

Differences between magnetic responses to red-green chromatic gratings and yellow-black luminance gratings were: (1) response waveforms differed considerably; (2) at some recording sites the chromatic grating response was considerably greater than the sum of responses to the red and green components of the chromatic grating; (3) the latencies of the successive peaks in the response to the onset of chromatic contrast were greater than the latencies of the corresponding peaks in the response to luminance contrast onset; (4) chromatic grating responses were lowpass with respect to spatial frequency while luminance grating responses were bandpass; (5) chromatic grating responses attenuated more steeply with increasing frequency above 2 c/deg than did luminance grating responses. Items (3)-(5) above are consistent with well-known psychophysical findings that contrast sensitivity is lowpass for chromatic gratings and chromatic responses are more sluggish than luminance responses. In subsidiary experiments we found that magnetic responses to red-green and blue-yellow equiluminant gratings had similar waveforms in all six subjects tested, but the topographical distributions were different in three subjects. The results of comparing magnetic and electrical responses to the onset and offset of contrast can be understood in terms of the considerable intersubject variability in the relation between neuroanatomy and cortical function that has been demonstrated by other techniques.

Adult↗
PubMed1996

A PC-based ultrasonic data acquisition system for computer-aided prosthetic socket design.

A PC-based ultrasound data acquisition system has been developed which uses compound scanning techniques to image a residual limb in a water tank. From the received ultrasonic eco data, the system produces cross-sectional images and reconstructs a three-dimensional (3-D) model of the limb. A commercial software for computer-aided prosthetic socket design was modified so that it can display both the external shape and cross-sectional image of the limb and allow the prosthetist to perform socket design with the help of a visualization of the limb's internal structure. The image resolution and measurement accuracy of the system were tested using a wire phantom and a contrast tissue mimicking phantom, respectively. Preliminary results from amputee patients are presented and the sources of measurement error are discussed.

Computer-Aided Design↗
PubMed1996

Selection of the bovine papillomavirus type 1 nucleotide 3225 3' splice site is regulated through an exonic splicing enhancer and its juxtaposed exonic splicing suppressor.

Alternative splicing is an important mechanism for the regulation of bovine papillomavirus type 1 (BPV-1) gene expression during the virus life cycle. However, one 3' splice site, located at nucleotide (nt) 3225, is used for the processing of most BPV-1 pre-mRNAs in BPV-1-transformed C127 cells and at early to intermediate times in productively infected warts. At late stages of the viral life cycle, an alternative 3' splice site at nt 3605 is used for the processing of the late pre-mRNA. In this study, we used in vitro splicing in HeLa cell nuclear extracts to identify cis elements which regulate BPV-1 3' splice site selection. Two purine-rich exonic splicing enhancers were identified downstream of nt 3225. These sequences, designated SE1 (nt 3256 to 3305) and SE2 (nt 3477 to 3526), were shown to strongly stimulate the splicing of a chimeric Drosophila doublesex pre-mRNA, which contains a weak 3' splice site. A BPV-1 late pre-mRNA containing the nt 3225 3' splice site but lacking both SE1 and SE2 was spliced poorly, indicating that this 3' splice site is inherently weak. Analysis of the 3' splice site suggested that this feature is due to both a nonconsensus branch point sequence and a suboptimal polypyrimidine tract. Addition of SE1 to the late pre-mRNA dramatically stimulated splicing, indicating that SE1 also functions as an exonic splicing enhancer in its normal context. However, a late pre-mRNA containing both SE1 and SE2 as well as the sequence in between was spliced inefficiently. Further mapping studies demonstrated that a 48-nt pyrimidine-rich region immediately downstream of SE1 was responsible for this suppression of splicing. Thus, these data suggest that selection of the BPV-1 nt 3225 3' splice site is regulated by both positive and negative exonic sequences.

Animals↗
PubMed1996

Ca2+ entry through conductive pathway modulates receptor-mediated increase in microvessel permeability.

We investigated the relationship between receptor-mediated increases in cytoplasmic Ca2+ concentration ([Ca2+]i) and increased microvessel permeability. In individually perfused venular microvessels of frog mesentery exposed to 10 microM ATP, [Ca2+]i increased from 59 +/- 7 to 172 +/- 21 nM within 1 min and then fell back toward control values. The corresponding peak increase in the hydraulic conductivity (Lp) of the microvessel wall was 5.7 +/- 0.5-fold relative to control. After removal of extracellular Ca2+, there was no significant increase in Lp, and the initial increase in [Ca2+]i was attenuated but not abolished. Depolarization of the endothelial cell membrane with high-K+ Ringer solution reduced the peak increase in [Ca2+]i to 106 +/- 7 nM and attenuated the increase in Lp 1.8 +/- 0.4-fold. The results conform to the hypothesis that Ca2+ entry into endothelial cells is required for acute increase in venular microvessel permeability by inflammatory agents and that the pathway for Ca2+ entry has the properties of a passive conductance pathway. Similar conclusions were reached in previous experiments in frog microvessels exposed to Ca2+ ionophores and perfusates with no plasma proteins. In venular microvessels of hamster mesentery exposed to ATP and bradykinin, a similar pathway for Ca2+ entry was demonstrated in the present experiments. We did not measure permeability changes in hamster microvessels in this study, but these microvessels respond to histamine and ionophores with a transient increase in permeability to macromolecules similar to that measured in frog microvessels [Am. J. Physiol. 268 (Heart Circ. Physiol. 37): H1982-H1991, 1995].

Adenosine↗
PubMed1995

Structure of the Leptomonas seymouri trans-spliceosomal U2 snRNA-encoding gene; potential U2-U6 snRNA interactions conform to the cis-splicing counterpart.

We have characterized the U2 small nuclear RNA (snRNA)-encoding gene from the monogenetic trypanosomatid, Leptomonas seymouri (Ls), to begin to identify the RNA-RNA interactions that direct trans-splicing in kinetoplastid protozoa. The U2 gene, which is single copy in this organism, was isolated and sequenced. Although the Ls U2 snRNA contains many of the sequence and secondary structure elements that are conserved among the U2 snRNAs of cis-splicing organisms, it lacks the stem-loop III region and the intron branch point-recognition region, as do other trypanosomatid U2 snRNAs. A transcriptional promoter element within the Trypanosoma brucei U2 gene [Fantoni et al., Mol. Cell. Biol. 14 (1994) 2021-2028] is conserved in the homologous Ls gene. A crucial step in cis-splicing reactions involves specific base-pairing interactions between the U2 and U6 snRNAs. We show here that in trypanosomatids, where no cis-splicing occurs, these same interactions are possible. This highlights key similarities between the two RNA processing events.

Animals↗
PubMed1995

Measurement of membrane potential of endothelial cells in single perfused microvessels.

The membrane potential is an important modulator of calcium ion flux into endothelial cells of venular microvessels. We developed a method to measure the membrane potential of endothelial cells forming the walls of individually perfused microvessels under the same experimental conditions as those used to measure cytoplasmic calcium concentration and microvessel permeability. The membrane potential-sensitive fluorescent dye, bis-oxonol (1 microM), was added to the perfusate and the changes in bis-oxonol fluorescence intensity (FI) were calibrated in terms of changes in membrane potential using the cationic ionophore, gramicidin. FI changes an average of 0.625% per millivolt. The resting membrane potential of endothelial cells measured in single perfused microvessels, each calibrated individually, was 51.6 +/- 4.9 mV (n = 9). In the presence of high potassium Ringer's solutions (57.9 and 100 mM, [K+]o), the membrane depolarized 25 +/- 3 and 40 +/- 5 mV, respectively. Conversely, low potassium solutions (0.1 mM [K+]o) hyperpolarized the membrane by 23 +/- 4 mV. The endothelial membrane was also depolarized when the Na-K-ATPase was inhibited with ouabain. This method provides new data to test current hypotheses describing the role of the endothelial cell membrane potential as a modulator of microvessel permeability.

Animals↗
PubMed1995

An audio-visual convergence area in the human brain.

By recording the magnetic field of the human brain while simultaneously presenting light to the eye and sound to the ear we have identified a brain region where auditory and visual signals converge. The location of this region is close to primary auditory cortex and far from primary visual cortex.

Auditory Pathways↗
PubMed1995

Quantitative reverse transcription-PCR analysis of Legionella pneumophila-induced cytokine mRNA in different macrophage populations by high-performance liquid chromatography.

Cytokine production in macrophages infected by bacteria is critical for the course of infection. However, it is not known how infection of macrophages with opportunistic bacteria leads to cytokine production in different populations of cells. Since it is possible that cytokine genes may be differentially regulated by attachment rather than by active infection, the levels of various cytokine mRNAs were measured in alveolar macrophages (AMs), peritoneal resident macrophages (RMs), and peritoneally elicited macrophages (EMs) interacting with Legionella pneumophila by using cytochalasin D-treated macrophages and a newly developed quantitative reverse transcription-PCR procedure with high-performance liquid chromatographic analysis to determine cytokine mRNA formation. Increased levels of interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, and macrophage inflammatory protein 2 mRNAs were quantitated in the macrophages responding to L. pneumophila attachment in vitro. Using this technique, we showed that the three different macrophage populations responded differently to bacterial attachment. We found that the levels of IL-6 and granulocyte-macrophage colony-stimulating factor mRNAs induced by the attachment of L. pneumophila to AMs were significantly lower than the levels in RMs but similar to the levels in EMs. Furthermore, the levels of MIP-2 mRNA in the AMs were found to be higher than those in the RMs, but similar levels were found in EMs. IL-1 beta mRNA levels were higher in both AMs and RMs than in EMs, but tumor necrosis factor alpha levels were not different among the three macrophage populations examined. Thus, the responses of macrophages to bacterial attachment in terms of cytokine mRNA levels were readily quantitated by the reverse transcription-PCR assay. However, the results obtained showed different levels of responsiveness of distinct macrophage populations to L. pneumophila attachment, and this could be related to the characteristic nature of the macrophage type examined.

Animals↗
PubMed1995

Magnetic and electrical responses of the human brain to texture-defined form and to textons.

1. We searched for a neurophysical correlate of preattentive texture discrimination by recording magnetic and electric evoked responses from the human brain during the first few hundred milliseconds following the presentation of texture-defined (TD) checkerboard form. The only two textons that changed when the TD checkerboard appeared or disappeared were the local orientation and line termination textons. (Textons are conspicuous local features within a texture pattern). 2. Our evidence that the magnetic response to TD form cannot be explained in terms of responses to the two associated textons is as follows: 1) by dissociating the two responses we showed that the magnetic response to TD form is almost entirely independent of the magnetic response to the local orientation texton; 2) a further distinction between the two responses is that their distributions over the head are different; and 3) the magnetic response to TD form differs from the magnetic response to the line termination texton in both distribution over the head and waveform. We conclude that this evidence identifies the existence of a brain response correlate of preattentive texture discrimination. 3. We also recorded brain responses to luminance-defined (LD) checkerboard form. Our grounds for concluding that magnetic brain responses to the onset of checkerboard form are generated by different and independent neural systems for TD and LD form are as follows: 1) magnetic responses to the onset of TD form and LD form had different distributions over the skull, had different waveforms, and depended differently on check size; and 2) the waveform of the response to superimposed TD and LD checks closely approximated the linear sum of responses to TD checks and LD checks alone. 4. One possible explanation for the observed differences between the magnetic and electric evoked responses is that responses to both onset and offset of TD form predominantly involve neurons aligned parallel to the skull, whereas that is not the case for responses to LD form.

Adolescent↗
PubMed1995

The selection of protein intake by pigs treated with porcine somatotropin.

The hypothesis that pigs can select a protein intake to meet their lean growth requirement when given a choice of two diets, differing in protein content, was tested in this study. Seventy-two gilts (PIC Camborough x Canabrid), of an average initial body weight of 20 kg, were allotted to one of four pens with half-slatted concrete floors and two electronic feeders. Two pens of pigs were assigned to a choice-feeding system (choice) and two pens to a single-feeding system (single). Half of the pigs in each pen received a daily injection of 100 micrograms/kg BW of porcine somatotropin (ST) and the other half received a daily injection of saline. Feed intake of individual pigs was recorded on a daily basis with the Feed Intake Recording Equipment (FIRE) system. Pigs assigned to the choice-feeding system were given two feeds of different protein content, 10 or 24%, but with similar digestible energy content (13.7 MJ of DE/kg). The single diet contained 16% CP during the grower period and 14% throughout the finisher period. Overall weight gain of pigs was not affected by feeding system or ST injection; however, feed intake was decreased by injection of ST (P = .006) and by choice feeding (P = .005). Choice-fed pigs showed decreased dietary protein intake compared with single-fed pigs. The increased deposition rate of lean and protein with injection of ST did not stimulate an increase in protein consumption. Choice feeding and ST injection lowered the amount of feed or protein required per unit gain, or per unit of lean or protein deposited.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1995

Visualization of endothelial clefts and nuclei in living microvessels with combined reflectance and fluorescence confocal microscopy.

OBJECTIVE: The cellular basis for spatial heterogeneity along postcapillary venules in their response to inflammatory mediators is not understood. To study permeability regulatory processes on an individual cell basis in intact microvessels, we developed methods to delineate individual endothelial cells within living, single perfused microvessels. METHODS: Individual postcapillary microvessels in the mesenteries of frogs and hamsters were perfused with chloride-free Ringer's solutions containing AgNO3 (0.1 g per 100 ml) for 5--10 s. Vessels were immediately flushed with Ringer's solution containing serum albumin and some vessels subsequently perfused with the fluorescent nucleic acid stain YO-PRO-1 (1 microM) for 10-15 min. Vessels were imaged in situ using laser scanning confocal microscopy. A reflectance image from silver precipitate in the endothelial clefts and a fluorescence image of the nuclei were simultaneously recorded. Stacks of confocal images were merged and used to reconstruct the three-dimensional orientation of endothelial cells. Hydraulic conductivity of some frog mesenteric venular vessels, measured before and after perfusion with AgNO3, was used to assess the integrity of the vessels. RESULTS: The endothelial cell clefts were delineated with a very fine, readily imaged precipitate of silver. Hydraulic conductivity measured after AgNO3 perfusion in frog mesenteric venular microvessels was not significantly different from control. Vessels showed a slight reduction in reactivity to inflammatory stimuli. The three-dimensional pattern of endothelial cells in the living vessels was imaged. CONCLUSIONS: Combining confocal microscopy with silver staining in single perfused microvessels was shown to be an effective means to delineate the three-dimensional pattern of endothelial cells forming microvessel walls. It enables further study of the vascular structure and function relationships at the individual cell level in intact microvessels.

Animals↗
PubMed1995

[Effects of manganese on learning abilities in school children].

Manganese in drinking water of Wu Village, Qingchu County, Taiyuan, Shanxi Province persisted in an excessive level all the year round, hair and blood manganese contents in its primary school pupils, averaged 1.242 micrograms/g and 617 nmol/L (3.39 micrograms/dl), respectively, were higher than those in normal children, and the school records of the former were poorer than those of the latter. Levels of serum 5-hydroxytryptamine (5-HT), dopamine, norepinephrine and acetylcholine esterase of those 92 school children were determined to study their relationship with poor learning abilities. Results showed levels of four neurotransmitter in them all were lower than those in control children. School records for Chinese language and mathematics correlated positively to the levels of most neurotransmitter. Multiple linear regression analysis showed the order of the effects of neurotransmitter on school records of Chinese language was 5-HT, norepinephrine, acetylcholine esterase and dopamine, and those on mathematics was norepinephrine, 5-HT, acetylcholine esterase and dopamine.

Adolescent↗
PubMed1995

[Laryngeal paralysis and laryngospasm].

The intrinsic laryngeal muscle potential was recorded with electromyography. Vocal cord movements were observed by a video stroboscope. Laryngeal paralysis is divided into mild, moderate, and severe degrees based on the potentials of intrinsic laryngeal muscles and on the status of vocal cord movements. In the past 11 years (from 1983 to 1993) 1211 cases were diagnosed as having mild, moderate, and severe laryngeal paralysis. Among them, there were 11 cases with laryngospasm including 3 mild, 2 moderate, and 6 severe cases. The findings obtained from careful observation on these 11 cases of laryngospasm demonstrated that there were certain relationships between laryngeal paralysis and laryngospasm. During the course of exacerbation or restoration of paralysis, the laryngospasm may occur.

Adult↗