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Biomedical subjects

H Yang

Publications and source records attributed to H Yang.

At least 649 records · Page 36Linked to original sources
PubMed1997

Lumbosacral plexus: a histological study.

Two hundred and forty histological paraffin sections were obtained from the midportion of the spinal nerve roots of 20 lumbosacral plexus (from L4 to S3) bilaterally. All microscopic images were digitized using the NIH image software with a Nikon microscope and Sony videocamera. The total, fascicular as well as epineurial cross-sectional areas of the nerve roots in the lumbosacral plexus were determined. The total cross-sectional area of the lumbosacral trunk (LST) was the largest (28.56 +/- 12.28 mm2) followed by the S1 (21.97 +/- 11.22 mm2) and L5 (21.00 +/- 8.79 mm2) nerve roots. The total cross-sectional areas of the L4 (6.93 +/- 3.32 mm2), S2 (13.93 +/- 5.86 mm2) and S3 (6.03 +/- 3.74 mm2) were significantly lower. Statistical differences were found among all absolute values at different levels (p < 0.0001) with the exception of the levels between L4 and S3, L5 and S1, and LST and S1 (p > 0.05). The total areas occupied by the fascicles in L5 (7.78 +/- 3.26 mm2), LST (9.97 +/- 4.01 mm2) and S1 (8.55 +/- 3.27 mm2) nerve roots were greater than those in L4 (2.96 +/- 1.50 mm2), S2 (5.56 +/- 2.34 mm2) and S3 (2.28 +/- 1.14 mm2). However, the percentages of the total cross-sectional areas occupied by the fascicles in the L5 nerve root (38%) and LST (36.4%) were smaller compared to other nerve roots (44.9% at L4, 40.5% at S1, 40.8% at S2 and 41.6% at S3). The cross-sectional areas and percentages of the epineurium were greater in L5 (13.22 +/- 6.48 mm2, 62.0%), LST (18.58 +/- 9.31 mm2, 63.6%) and S1 (13.42 +/- 8.88 mm2, 59.5%) roots. The L5 (12.1 +/- 5.0), LST (27.5 +/- 11.4) and S1 (15.0 +/- 7.3) roots contained more fascicles than L4 (6.3 +/- 3.3), S2 (9.5 +/- 4.1) and S3 (7.1 +/- 2.7). Statistical differences were found among all absolute values at different levels (p < 0.0001) with the exception of the levels between L4 and S3, L5 and S1 and LST and S1 (p > 0.05). No statistical differences were found for percentages among different levels (p > 0.05) with the exception of the levels between L4 and L5, L4 and LST, LST and S1, LST and S2, and LST and S3 (p < or = 0.05). The histological structure of nerve roots of the lumbosacral plexus is identical to that of the peripheral nerve. The midportions of L5 and S1 roots and the LST have a relatively higher epineurial content. These nerve roots also have a greater number of the fasicles, but the total cross-sectional area occupied by the fascicles is less than in L4, S2 and S3 nerve roots.

Adult↗
PubMed1997

Cartilage and synovium of the human atlanto-odontoid joint. An anatomic and histological study.

The surface area, thickness and composition of articular cartilage of the atlanto-odontoid joints were investigated in twenty human cadaveric cervical spine specimens. The specimens were also examined grossly and by light microscopy to determine the location of the synovium. The anterior arch of the atlas and ventral and dorsal articular surfaces of the dens were covered with hyaline cartilage. The mean values of the articular surface areas on the ventral surface of the dens and anterior arch of the atlas were 55.10 and 58.24 mm2, respectively. The mean thickness of the articular cartilage of the anterior arch of the atlas, ventral and dorsal surfaces of the dens was 0.80, 0.81 and 0.82 mm, respectively. Synovial membranes were associated with the joint capsules and surrounding tissues of both anterior and posterior atlanto-odontoid joint spaces, where the synovial membranes were attached to the margins of the articular surfaces of the dens and anterior arch of the atlas anteriorly and the region of the cruciate ligament immediately peripheral to the cartilage region apposed to the dens and dens cartilage itself, posteriorly.

Adult↗
PubMed1997

Angiotensin II-induced phosphorylation of the AT1 receptor from rat brain neurons.

The neuronal angiotensin II (Ang II) type 1 (AT1) receptor is coupled to the Ras-Raf-1-mitogen-activated protein (MAP) kinase signal-transduction pathway (Yang H, Lu D, Yu K, Raizada MK. Regulation of neuromodulatory actions of angiotensin II in the brain neurons by the Ras-dependent mitogen-activated protein kinase pathway. J Neurosci. 1996;16:4047-4058). In this study we compared the effects of angiotensin II (Ang II) on AT1 receptor phosphorylation and the ability of the phosphorylated receptor to bind Ang II in neuronal cultures of Wistar-Kyoto rat (WKY) and spontaneously hypertensive rat (SHR) brains to further our understanding of the Ang II signaling mechanism. Ang II caused a time-dependent phosphorylation of AT1 receptors in both WKY and SHR brain neurons. The level of phosphorylation was higher in the SHR brain neurons; this finding was consistent with increased AT1 receptors in these cells. MAP kinase was involved in this phosphorylation, a conclusion supported by the following evidence: (1) exogenous MAP kinase phosphorylated the AT1 receptor; (2) PD98059, a MAP kinase kinase inhibitor, attenuated Ang II-stimulated AT1 receptor phosphorylation; and (3) MAP kinase and AT1 receptors were coimmunoprecipitated in Ang II-stimulated neurons. Finally, MAP kinase phosphorylation was associated with the loss of 125I-[Sar1-Ile8]-Ang II binding ability of the AT1 receptor in both strains of neurons. These observations show that Ang II stimulates phosphorylation of the neuronal AT1 receptor by a mechanism involving MAP kinase and that the phosphorylated neuronal AT1 receptor does not exhibit Ang II binding activity in the brains of either WKY or SHR.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1997

Losartan versus gene therapy: chronic control of high blood pressure in spontaneously hypertensive rats.

Interruption of the renin-angiotensin system by pharmacological manipulations attenuates high blood pressure (BP) in the spontaneously hypertensive rat (SHR). However, these agents, such as losartan, need to be administered daily to maintain effective BP control. Therefore, we have hypothesized that a genetic intervention in the expression of angiotensin type 1 receptor (AT1R) should attenuate development of hypertension on a long-term basis in SHR. A retroviral-mediated AT1R antisense cDNA gene delivery system (LNSV-AT1R-AS) was used to test this hypothesis and to compare its BP-lowering effects with those of losartan. Introduction of LNSV-AT1R-AS into 5-day-old Wistar-Kyoto rats and SHR resulted in a robust expression of AT1R antisense (AS) within 3 days and persisted for at least 30 days. This expression was associated with a selective attenuation of high BP in SHR by 25 to 30 mm Hg. Although basal lowering of BP was exclusive to SHR, the angiotensin II (Ang II) pressor response was significantly reduced in all LNSV-AT1R-AS-treated rats. The decreased response to Ang II was associated with a similar attenuation of Ang II-induced dipsogenic responses in both strains of rats. The BP-lowering effects of LNSV-AT1R-AS treatment and losartan treatment were similar and primarily observed in SHR. However, the antihypertensive effect lasted less than 24 hours in losartan-treated SHR compared with 90 days in LNSV-AT1R-AS-treated SHR. In addition, losartan was unable to further lower BP in LNSV-AT1R-AS-treated SHR. Collectively, these results suggest that both losartan and LNSV-AT1R-AS treatment produces an antihypertensive response selectively in SHR that is mediated by interruption of AT1R function. However, a single, acute genetic treatment with LNSV-AT1R-AS can result in long-term control of high BP at a similar level of effectiveness as losartan, without altering plasma Ang II levels.

Animals↗
PubMed1997

Radiographic and CT evaluation of tibiofibular syndesmotic diastasis: a cadaver study.

Twelve cadaver lower limbs were used for radiographic and CT assessment of the tibiofibular syndesmosis. Plastic spacers were placed in the distal tibiofibular intervals of each specimen in successive 1-mm increments until diastasis could be appreciated on the plain radiographs. All 2- and 3-mm diastases could be noted and clearly identified on CT scans, while the 1-, 2-mm, and half of the 3-mm syndesmotic diastases could not be appreciated with routine radiographs. CT scanning is more sensitive than radiography for detecting the minor degrees of syndesmotic injuries. Therefore, a CT scan can be performed in cases of syndesmotic instability after ankle injuries and for preoperative or postoperative evaluation of the integrity of the distal tibiofibular syndesmosis in cases of doubtful condition of the syndesmosis.

Cadaver↗
PubMed1997

Protein nutrition of gestating sows.

Dietary amino acid requirements of gestating sows vary depending on genetic strain, energy intake, body weight, and other factors. Estimation of amino acid requirements for gestating sows in a defined situation should be directed toward achieving a high rate of protein accretion and a modest rate of fat accretion. More information is needed to set target accretion rates precisely. A simple mathematical model was developed with the limited objectives of 1) aiding in understanding the interactions among energy intake, amino acid intake, protein accretion potential, and body weight in affecting the amount of body protein and fat accreted by pregnant sows and 2) providing general guidelines for feeding programs. Predictions from the model suggest that the daily lysine requirement varies markedly with variation in ME intake but that the requirement as a percentage of the diet is more stable as ME intake varies. At moderate ME intake, the lysine requirement seems greater during late gestation than earlier. The lysine requirement of heavy sows is less than that of light gilts at a similar ME intake, and this offers opportunity for modest cost savings in pork production. A compromise is necessary between the goals of a high rate of protein accretion and a modest rate of fat accretion. It seems that a sow's potential protein accretion rate is rarely limiting.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Evaluation of milk chocolate product as a substitute for whey in pig starter diets.

Four experiments were conducted to study the effects of substituting milk chocolate product MCP) for dried whey (DW) on growth performance of starter pigs. In Exp. 1 (4 wk) and 2 (5 wk), 440 pigs (age, 25 d) were assigned to one of four diets: 1) 0% DW + 0% MCP, 2) 20% DW + 0% MCP, 3) 10% DW + 10% MCP, or 4) 0% DW + 20% MCP. Linear reductions (P < .06) in ADG, ADFI, and gain/feed (G/ F) were detected as MCP increased. Replacement of DW with 10% MCP had little effect on ADG or ADFI in Exp. 1, but it reduced them in Exp. 2. In Exp. 3(5 wk), 192 pigs (age, 20 d) were fed one of four complex diets: 1) 15% DW + 0% MCP, 2) 10% DW + 5% MCP, 3) 5% DW + 10% MCP, or 4) 0% DW + 15% MCP. As MCP increased, ADG and ADFI decreased linearly (P < .01), but growth performance was similar between pigs fed the 0 and 5% MCP diets. Experiment 4 was a 14-d preference trial in which the four diets from Exp. 3 and 270 pigs (age, 24 d) were used to make three comparisons: a) diet 1 vs diet 2, b) diet 1 vs diet 3, and c) diet 1 vs diet 4. Pigs consumed between 65 and 77% of their total feed intake as MCP-containing diets (P < .01). In summary, MCP could replace DW at a dietary level of 5% without reducing pig performance, but MCP at dietary levels of 10% or more reduced pig performance. Pigs strongly preferred MCP over DW.

Animals↗
PubMed1997

Stimulation of intestinal growth is associated with increased insulin-like growth factor-binding protein 5 mRNA in the jejunal mucosa of insulin-like growth factor-I-treated parenterally fed rats.

Surgically stressed rats maintained with total parenteral nutrition (TPN) exhibit jejunal atrophy, which can be attenuated by insulin-like growth factor-I (IGF-I) but not by growth hormone (GH) treatment. In order to understand the basis for the selective action of IGF-I, the levels of mRNAs encoding IGF-I, IGF-binding proteins (IGFBPs), IGF-I receptor, and GH receptor/binding protein (GHR/GHBP) were determined in rats given TPN and treated with GH, IGF-I, or GH + IGF-I. GH treatment significantly stimulated hepatic IGF-I mRNA. IGF-I treatment did not alter liver IGF-I mRNA, nor was there any evidence for interaction between GH and IGF-I. Jejunal mucosa IGF-I mRNA was extremely low and was not altered by TPN or by any of the hormonal treatments. The inability of GH to stimulate jejunal growth was not associated with a deficiency in GHR/GHBP mRNA. In jejunal mucosa, IGF-I and GH treatment independently and synergistically stimulated IGFBP-3 mRNA. IGF-I stimulated jejunal IGFBP-5 mRNA, but GH had no effect on IGFBP-5 mRNA. The levels of IGF-I receptor and IGFBP-1, 2, 4, and 6 mRNAs were extremely low and/or were not altered by any of the treatments. These results suggest that the ability of exogenous IGF-I, but not GH, to induce IGFBP-5 mRNA in jejunal mucosa may lead to the selective growth-promoting effect of IGF-I. Jejunal mucosa IGFBP-3 mRNA levels were not correlated with altered growth. We postulate that IGFBP-5 positively modulates the anabolic effects induced by exogenous IGF-I in the jejunum.

Animals↗
PubMed1997

[One-stage reconstruction with the pectoralis major myocutaneous flap for the pharyngectomy].

18 patients with the advanced oropharyngeal cancer from October 1983 to July 1992 were retrospectively studied in our hospital. The blood supply of the pectoralis major myocutaneous flap (PMMF). PMMF came mainly from the pectoral branch of the acromiothoracic artery. The flap area ranged from 15 cm x 10 cm to 3 cm x 3 cm. 3 cases had partial necrosis and 4 cases received prophylactic tracheotomy. The cosmetic and functional restoration was satisfactory in most of the patients. The factors which affected the wound healing were also discussed. The 3 year and 5 year survival rates were 61.5% and 40%, respectively. This paper revealed that the PMMF was the first choice for the defect of the pharyngectomy.

Adult↗
PubMed1997

[Long-term survival of fetal substantia nigra grafts in striatum of PD rats: an observation of tyrosine hydroxylase immunohistochemistry and western blot].

By using immunohistochemistry and Western blot, we observed the varied patterns of survival, development and growth of dopaminergic neurons after intrastriatal transplantation of fetal substantia nigra. There was a phenomenon of "developmental delay" of grafts in the host. As the time of transplantation went on, the grafted dopaminergic neurons could reinnervate the host neurons. The observation reveals that the reinnervation between graft and host is more beneficial to the functioning of the grafts.

Animals↗
PubMed1997

[Intraparenchymal and intraventricular transplantation of fetal substantia nigra cell suspension in rat model of Parkinson's disease].

The grafts of fetal substantia cell suspension grafts could bring into a behavioral effect and characteristics of histology and immunocytochemistry in rat models of PD after the grafts were transplanted either into the lateral ventricles or directly into the striatum. It was found that the intraparenchymal tromsplantation of fetal nigral cell suspensions not only was beneficial to reinnervation between host and grafts, but also produced more complete and steady effects than the intraventricular transplantation. We concluded that the restoration of nervous functional deficits of PD rats is likely to depend on both extensive dopaminergic reinnervation throughout the grafted sites and on closer integration of the grafts with the host striatal circuitry.

Animals↗
PubMed1997

[Corneal topography analysis before and after photorefractive keratectomy].

OBJECTIVE: To study the change of corneal surface morphology before and after photorefractive keratectomy (PRK) and analyze the decentralization of the ablation. METHODS: Corneal topography was examined on 122 eyes of 80 cases with myopia by computer-assisted photokeratography before and after PRK. RESULTS: Before PRK, the corneal topography of most examined eyes (75.4%) was symmetric bow tie pattern or asymmetric bow tie pattern; after PRK, the corneal topography of the ablated regions was mainly round or approximately round (63.9%). There is no relationship between the distance of decentralization of the ablation site and preoperative refractive diopters. But the more is the distance of decentralization, the more is the increase of postoperative corneal astigmatism and also the more is the decrease of the best corrected visual acuity. CONCLUSION: Examination and analysis on the corneal topography before and after PRK can clearly display the changes of the corneal surface morphology, and also can quantitatively evaluate the decentralization.

Adult↗
PubMed1997

[Color Doppler ultrasonography in evaluation of intraocular lesions].

OBJECTIVE: To evaluate the value of color Doppler ultrasonography (CDU) in the diagnosis of intraocular lesions. METHODS: 82 cases of intraocular diseases were examined by high-resolution CDU (7.5 mHz), and the blood flow pattern was evaluated at the base of two-dimensional image. RESULTS: CDU might show the blood flow of retinal vessels in all 21 cases of retinal detachment, no blood flow could be detected in 21 of 22 vitreous hemorrhages and/or membranes, and only in one case with diabetic proliferative retinopathy did fine blood flow be seen. Intratumor blood flow with branchy pattern could be detected in 17 of 18 cases with choroidal melanomas and 3 of 4 cases with choroidal metastatic carcinoma, and spectral analysis revealed high-resistance, simulating arterial blood flow waves. In 5 cases with choroidal hemangioma, intratumor blood flow with filled or sparkled pattern was detected, and the spectral analysis revealed both arterial and venous blood flow waves. No blood flow in the lesion was detected in simulating benign lesions i.e. 5 choroidal hemorrhages and 2 subretinal hemorrhages. In 3 cases (4 eyes) with persistent hyperplastic primary vitreous (PHPV), CDU showed band-shaped arterial blood flow coursing from optic nerve disc to the posterior surface of the lens in the vitreous cavity. CONCLUSION: CDU is helpful in the differential diagnosis among retinal detachment, vitreous hemorrhage, vitreous membrane, malignant choroidal melanoma, choroidal metastatic tumor, choroidal benign lesion or hemangioma, PHPV and lesions with white pupil.

Adolescent↗
PubMed1997

A clinical study on compound da huang (radix et Rhizoma rhei) preparations for improvement of senile persons' memory ability.

By comparison of the effects of the Compound Tong Jiang Oral Liquid with Da Huang added (TJ [symbol: see text]) and Qi Yin Oral Liquid (QY [symbol: see text]) without Da Huang on senile persons' memory ability, it is discovered that the effects of TJ on shortening the interval between defecations and the duration of defecation, and on improving senile persons' memory ability are significantly better than that of QY (P < 0.05). In addition, TJ can also decrease the serum content of lipid peroxidase and increase the superoxide dismutase activity in red blood cells (RBC). Thus, it is demonstrated that Dahuang and its agents possess the action of anti-senility and can improve mentality.

Aged↗
PubMed1997

[Efficient expression of human C1-inhibitor in CHO cells by using a dicistronic expression vector].

The full-length cDNA fragment encoding human C1-INH was obtained by gene recombination techniques and a stable expression plasmid was constructed by inserting the human C1-INH cDNA into an efficient dicistronic expression vector pED. This plasmid was transfected into DHFR-deficient Chinese Hamster Ovary cells (CHO-dhfr-) by Lipofectin method, and the positive CHO-dhfr+ cell clones which stably express C1-INH was generated. Expression of C1-INH mRNA was detected by Northern blot. Expression of C1-INH protein was confirmed by immunoprecipitation and Western blot analysis. The level of expressed C1-INH was estimated at 0.4 microgram/ml by specific ELISA techniques. The biological activity of recombinant C1-INH was assayed by using the inhibition of C1 estrolytic activity.

Animals↗
PubMed1997

[Investigation on matrix degrading enzymes of lumbar intervertebral discs].

Changes in the macromolecular matrix of the intervertebral disc may predispose to biomechanical failure of the disc. Such changes would involve extracellular enzymes capable of altering the collagen and proteoglycan of the disc matrix. In this study, tritium-labeled type I collagen was used as a substrate to estimate the activity of collagenase in the discs of 41 cases of lumbar disc protrusion (LDP) patients by surgical intervention. The annulus fibrous (AF) and nucleus pulposus (NP) were measured separately. 34 normal discs harvested by autopsy acted as controls. For estimation of relative neutral proteinase content of 6 normal and 16 degenerated lumbar discs, polyacrylamide gelelectrophoresis (PAGE), heat-denatured collagen as a substrate, and photo-density scanning with peak area autocalculating system were adopted. The results presented that both AF and NP of the normal discs had a similar lower collagenolytic activity and a very limited activity of neutral proteinase, while the degenerated discs showed a higher activity, especially in the degenerated NP. The extruded type of LDP got a higher collagenolytic activity in NP than that of the prolapsed LDP. The fact showed that the matrix degrading enzymes play a very important role in the process of lumbar disc degeneration. The difference of disc degeneration is the biochemical basis of different clinical types of LDP. Matrix degrading enzyme system is a very complexed multienzymatic system. Other neutral proteinases may join this system besides the collagenase.

Adolescent↗
PubMed1997

[Immunogenecity of expressed protein p68 from recombinant plasmid rpDJt in L. interrogans serovar lai].

There are two types of infection caused by pathogenic microorganisms, intracellular infection and intercellular infection. Infection of pathogenic leptospira is an intercellular infection. The immunological reaction of host to intercellular infection is unique. The potential immunogen of an expressed protein should meet three criteria: it can be degraded (by antigen-present cells in the host); it should have antigenic epitope which can be recognized by specific antibodies and have at least one epitope that can be recognized by an MHC II protein and T cell receptor. In this study we report the cloning of an L. interrogans protein in plasmid rpDJt and the immunogencity of the expressed protein derivative. A genomic library of L. interrogans serovar lai strain 017 was constructed with the plasmid vector pUC18. Recombinant plasmids, designated pDJH2 and pDJ8 were screened from the bank. EcoRI-inserted fragment of 1. 9 kb recombinant DNA of pDJH2 was ligated into T7 RNA polymerase/promoter vectors (pT7-7). Then they were transformed into E. coli JM109 (De3), one of subclones, designated rpDJt was achieved. SDS-PAGE showed that the molecular weights of expression proteins were 68 kd and 23 kd respectively, designated p68 and p23. Purifying and isolating p68 and p23, we separated them from SDS-Polyacrylamide gels by using Side-Strip method. After fragmenting and electroeluting, p68 and p23 were injected into guinea pigs and rabbits. An extremely strong immune response to p68 was obtained since an anti-p68 antibody response could be detected to a dilution 1:524,288 (guinea pigs) and 1:262,144 (rabbits) by ELISA while anti-P23 antibody being 1:1024 (the same to guinea pigs and rabbits). The results of improved MTT and conA 3HTdR transformation methods showed the activities and proliferation of Th-cells were increased in guinea pigs after p68 immunization (IL-6, 83.25 IU/ml, IL-2, 28.75 IU/ml; RPI, 2.04, SI, 65.62%) Thlymphocyte existed in two subclasses, the Th1- and Th2-cells. A major role of Th2-cells is to "help" B-cells differentiate, replicate, and secrete antibody. The properties of these interactions explain why p68 makes good antigen and p23 does not. The antigens responsible for eliciting the production of protective antibodies are not known; however, several outer membrane proteins on L. interrogans are candidates for vaccine. Our results suggest that expresion protein p68 from recombinants (rpDJt) may be a candidate for gene engineered subunit vaccine for Leptospirosis.

Animals↗