Biomedical subjects

H Shu

Publications and source records attributed to H Shu.

At least 19 recordsLinked to original sources

PubMed2000

Drosophila Dscam is an axon guidance receptor exhibiting extraordinary molecular diversity.

A Drosophila homolog of human Down syndrome cell adhesion molecule (DSCAM), an immunoglobulin superfamily member, was isolated by its affinity to Dock, an SH3/SH2 adaptor protein required for axon guidance. Dscam binds directly to both Dock's SH2 and SH3 domains. Genetic studies revealed that Dscam, Dock and Pak, a serine/threonine kinase, act together to direct pathfinding of Bolwig's nerve, containing a subclass of sensory axons, to an intermediate target in the embryo. Dscam also is required for the formation of axon pathways in the embryonic central nervous system. cDNA and genomic analyses reveal the existence of multiple forms of Dscam with a conserved architecture containing variable Ig and transmembrane domains. Alternative splicing can potentially generate more than 38,000 Dscam isoforms. This molecular diversity may contribute to the specificity of neuronal connectivity.

Amino Acid Sequence↗

PubMed2000

Activation of PPARalpha or gamma reduces secretion of matrix metalloproteinase 9 but not interleukin 8 from human monocytic THP-1 cells.

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that directly control numerous genes of lipid metabolism by binding to response elements in the promoter. It has recently been proposed that PPARgamma may also regulate genes for proinflammatory proteins, not through PPRE binding but by interaction with transcription factors AP-1, STAT, and NF-kappaB. Recent studies with cultured human monocytes, however, have failed to observe an inhibitory effect of PPARgamma agonists on induced expression of TNFalpha and IL-6, genes known to be controlled by AP-1, STAT, and NF-kappaB. In a similar fashion, we show here that PPARalpha (fenofibrate) or PPARgamma (rosiglitazone) agonists failed to modulate LPS-induced secretion of IL-8 in THP-1 cells. When we made parallel observations on another gene, matrix metalloproteinase 9 (MMP-9), we were surprised to find profound downregulation of LPS-induced secretion by both PPARalpha or PPARgamma agonists. These findings suggest that PPAR may regulate only a subset of the proinflammatory genes controlled by AP-1, STAT, and NF-kappaB. Effects of PPARs on MMP-9 may account for the beneficial effect of PPAR agonists in animal models of atherosclerosis.

Cell Nucleus↗

PubMed2000

The guanine nucleotide exchange factor trio mediates axonal development in the Drosophila embryo.

Recent analysis of Rho subfamily GTPases in Drosophila revealed roles for Rac and Cdc42 during axonogenesis. Here, we describe the identification and characterization of the Drosophila counterpart of Trio, a guanine nucleotide exchange factor (GEF) that associates with the receptor phosphatase LAR and regulates GTPase activation in vertebrate cells. Mutants deficient in trio activity display defects in both central and peripheral axon pathways reminiscent of phenotypes observed in embryos deficient in small GTPase function. Double mutant analysis shows that trio interacts with Rac in a dose-sensitive manner but not with Rho. Moreover, reduction of trio activity potentiates the phenotype of mutations in the LAR homolog Dlar, suggesting that these proteins collaborate in orchestrating the cytoskeletal events that underlie normal axonogenesis.

Animals↗

PubMed2000

Decrease in protein C inhibitor activity and acquired APC resistance during normal pregnancy.

BACKGROUND: Since protein C inhibitor (PCI) inhibits activated protein C (APC) and a number of proteases, one would expect lower concentrations of PCI in a hypercoagulable state due to increased consumption of the inhibitor. Normal pregnancy is associated with a state of activated hemostasis, where response to APC is depressed. We aimed to study whether PCI function varies during normal pregnancy, and assess the relationship between this inhibitor and acquired APC resistance. METHODS: PCI activity in plasma was tested during pregnancy and postpartum in 28 healthy pregnant women without factor V Leiden Arg(506) - Gln mutation and in 14 non-pregnant female controls. The PCI levels determined in the present study was compared to the APC ratio (APC-r), we investigated previously, in the same samples. RESULTS: The levels of PCI in the pregnant group, as compared to that in the control group (4.74 +/- 0.48), gradually decreased from the first to the third trimester, i.e., 3.30 +/- 1.31 microg/mL in week 12 (p < 0.001), 2.66 +/- 1.44 microg/mL in week 20 (p < 0.001), 1.92 +/- 1.18 microg/mL in week 28 (p < 0.001), 1.30 +/- 0.94 microg/mL in week 32 (p < 0.001) and 1.49 +/- 1.12 microg/mL in week 37 (p < 0.001). After delivery, they rose to 5.02 +/- 1.93 microg/mL, similar to that in the controls (p > 0.05). The values of APC-r showed the same tendency during gestation and postpartum. CONCLUSION: With advance of normal pregnancy, decreasing PCI function corresponds to increasing APC resistance, probably due to that activated hemostasis acts as a link connecting the two variables.

Activated Protein C Resistance↗

PubMed2000

Ordinal knowledge: number names and number concepts in Chinese and English.

Previous research has demonstrated cross-language variation in early counting associated with linguistic differences in number-naming systems. Ordinal number names are typically learned later than cardinal names, but languages also differ in the regularity with which they form these names. Elementary school children in China and the U.S. showed differences in the acquisition and use of ordinal numbers corresponding to linguistic differences in ordinal names in their native languages. On tasks assessing children's conceptual knowledge of ordinal relations, a more complicated picture emerged. These results suggest that (a) children induce their language's set of ordinal number names by generalization based on rules sanctioned by early examples, and (b) the relation between ordinal names and ordinal concepts is a complex one, with language only one source of difficulty in understanding ordinal relations. Implications for studies of the relation between linguistic structure and cognitive development are discussed, in particular the possibility that effects of linguistic differences may vary for different levels of development and for different aspects of cognition.

Child↗

PubMed1999

Optimizing computerized treatment planning for the Gamma Knife by source culling.

PURPOSE: A good plan is crucial to the success of gamma knife treatment, which depends not only on parameters such as the number of shots, shot position, collimator sizes, and shot weight, but also on the number of blocked cobalt sources. However, during treatment, a plug is generally used to block those cobalt sources, so the beam cannot reach critical tissues. We present here an automated method to optimize all of those parameters, and to choose a source set, although the beams of some blocked sources do not hit any critical tissue. This strategy is used to achieve a high dose that better conforms to the tumor shape, and at the same time, avoids healthy tissue. METHODS AND MATERIALS: Using a workstation that integrates the gamma knife treatment planning system, we developed a two-step optimization algorithm. First, we used a modified Powell's method to optimize the location of the shot, collimator size, and shot weight; we used simulated annealing to determine if the number of shots was adequate using this parameter. Then, simulated annealing was used to determine which cobalt sources we needed to block. RESULTS: Application of this optimization method in two cases showed that the treatment plan can be much improved when the set of blocked cobalt sources has been taken into consideration. CONCLUSION: Determining the set of blocked sources is necessary in certain cases. This technique better conforms the desired isodose curves to the outline of the target volume and minimizes damage to the surrounding normal tissues.

Algorithms↗

PubMed1999

[Anatomic study and review of the literature on the Martin Gruber anastomosis].

We dissected 72 upper limbs of fresh cadavers and found 17 cases of the Martin-Gruber anastomosis. The incidence was 23.6%. They can be classified into 5 types. Type I (n = 5, 29.4%): Communication between the anterior interosseous and the ulnar nerves. Type II (n = 3, 17.6%): Communication between the median and the ulnar nerves. Type III (n = 3, 17.6%): Communication between the muscular branches of the flexor digitorum profundus muscle (FDP). Type IV (n = 3, 17.6%): Communication between the anterior interosseous and the ulnar nerves, the muscular branches of the flexor digitorum profundus muscle (FDP) originated from the connection. Type V (n = 3, 17.6%): The anastomotic branch originated from the median nerve and joined the ulnar at two different points as well as connecting with the ulnar branch of the FDP. Through histologic examination, we found the number and size of nerve fascicles which every connection contained to be very different. In one case of type II only one single nerve fascicle was found. We propose the hypothesis that the different amounts of nerve fascicles innervate different amounts of intrinsic hand musculature. The communication which contained one single nerve fascicle only innervate the first dorsal interosseous muscle (FDI).

Aged↗

PubMed1999

A study on the methods for early serological diagnosis of leprosy and their potential use.

This is a serial study. In this series we have established 12 methods for the early serological diagnosis of leprosy, including the FLA-ABS test, ELISAs with artificial products (ND-O-, ND-P-, NT-O-, NT-P-BSA; PGL-I, whole M. leprae and M. smegmatis), monoclonal antibody specific binding assay (McAb/SBA), latex agglutination test (LAT), and MLPA. These methods were compared with each other on a large scale in leprosy patients and in the field. The results indicate that 1) Excellent results were obtained when ELISAs were conducted with skim milk or egg albumin as the blocking agent and by using blood from earlobes instead of from venipuncture. 2) According to the four "S" standard (sensitivity, specificity, simplicity and speed), among the 12 methods the ND-O-BSA-ELISA (ND-ELISA) is the best and the MLPA is more suitable for use in the field because it is simple and rapid. 3) In the ND-ELISA, the increase or decrease of the OD value has a positive correlation with the BI, and the order of positive rates was a) in various types of leprosy: LL > BL > BB > BT > TT; b) in household contacts (HC), random population (RP), normal controls in endemic areas (ENC) and normal controls in nonendemic areas (NNC): HC > RP > ENC > NNC. 4) In a population with subclinical M. leprae infection, the highest risk group was between the ages of 15 and 25 and had an increase or a persistence of high OD values prior to onset of disease. 5) OD values gradually decreased over time following treatment and these declines paralleled declines in the BI. 6) In cases cured with dapsone therapy, there was an increase or a persistence of high OD values in ND-ELISA prior to the onset of a leprosy relapse. In conclusion, we have compared and evaluated 12 immuno-assays and have shown that the ND-ELISA is the most practical one for use in investigating sero-immunological epidemiology, subclinical infection with M. leprae, early detection of disease, monitoring of antimicrobial therapy, and even for the prediction of leprosy relapse.

Antibodies, Bacterial↗

PubMed1998

Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone.

Insulin-like growth factor (IGF)-I and IGF-II are expressed at biologically effective levels by bone cells. Their stability and activity are modulated by coexpression of IGF binding proteins (IGFBPs). Secreted IGFBPs may partition to soluble, cell-associated, and matrix-bound compartments. Extracellular localization may sequester, store, or present IGFs to appropriate receptors. Of the six IGFBPs known, rat osteoblasts synthesize all but IGFBP-1. Of these, IGFBP-3, -4, and -5 mRNAs are induced by an increase in cAMP. Little is known about extracellular IGFBP localization in bone and nothing about IGFBP expression by nonosteoblastic periosteal bone cells. We compared basal IGFBP expression in periosteal and osteoblast bone cell cultures and assessed the effects of changes in cAMP-dependent protein kinase A or protein kinase C. Basal IGFBP gene expression differed principally in that more IGFBP-2 and -5 occurred in osteoblast cultures, and more IGFBP-3 and -6 occurred in periosteal cultures. An increase in cAMP enhanced IGFBP-3, -4, and -5 mRNAand accordingly increased soluble IGFBP-3, -4, and -5 and matrix-bound IGFBP-3 and -5 in both bone cell populations. In contrast, protein kinase C activators suppressed IGFBP-5 mRNA, and its basal protein levels remained very low. We also detected low Mr bands reactive with antisera to IGFBP-2, -3, and -5, suggesting proteolytic processing or degradation. Our studies reveal that various bone cell populations secrete and bind IGFBPs in selective ways. Importantly, inhibitory IGFBP-4 does not significantly accumulate in cell-associated compartments, even though its secretion is enhanced by cAMP. Because IGFBPs bind IGFs less tightly in cell-bound compartments, they may prolong anabolic effects by agents that increase bone cell cAMP.

Animals↗

PubMed1998

Three-dimensional optimization of treatment planning for gamma unit treatment system.

During a treatment using the Leksell gamma unit, the physician and physicist need to determine a treatment plan by changing the parameters such as collimator sizes, the position of isocenters and isocenters' weights. This is a complex problem because the set of parameters is large, especially when targets are geometrically close to a critical structure. For this reason, we present here an optimization algorithm, namely the multiplier penalty method, to mathematically determine those parameters. Two cases are presented in this article: the first one is really planned by a physicist in a clinical treatment, and is redone in our optimization algorithm to show the effectiveness of this method; the second one is theoretical where a critical structure is placed close to the target volume. The results show that this method achieves an excellent conformation to the specified isodose curve with the contour of the target volume, allowing minimal damage to surrounding healthy tissue.

Algorithms↗

PubMed1998

[Ultrasonographic rating score in evaluation of pathological severity and timing of operation for acute cholecystitis].

A rating score of ultrasonography to evaluate the pathological severity and timing of operative intervention of acute cholecystitis was designed. The ultrasonic rating score consisted of 7 items with were sensitive and specific in diagnosis of acute cholecystitis, accorded with the findings during operation. Emergency cholecystomies performed on patients with score < or = 10, 11-18 and > 18 points were 1/30, 4/42 and 7/13 respectively, followed by definite procedures. The results suggest that the ultrasonographic rating score is an useful approach in ultrasound diagnoses and timing of operation for acute cholecystitis.

Acute Disease↗

PubMed1997

Clinical treatment planning optimization by Powell's method for gamma unit treatment system.

PURPOSE: This article presents a new optimization method for stereotactic radiosurgery treatment planning for gamma unit treatment system. METHODS AND MATERIALS: The gamma unit has been utilized in stereotactic radiosurgery for about 30 years, but the usual procedure for a physician-physicist team to design a treatment plan is a trial-and-error approach. Isodose curves are viewed on two-dimensional computed tomography (CT) or magnetic resonance (MR) image planes, which is not only time consuming but also seldom achieves the optimal treatment plan, especially when the isocenter weights are regarded. We developed a treatment-planning system on a computer workstation in which Powell's optimization method is realized. The optimization process starts with the initial parameters (the number of isocenters as well as corresponding 3D isocenters' coordinates, collimator sizes, and weight factors) roughly determined by the physician-physicist team. The objective function can be changed to consider protection of sensitive tissues. RESULTS: We use the plan parameters given by a well-trained physician-physicist team, or ones that the author give roughly as the initial parameters for the optimization procedure. Dosimetric results of optimization show a better high dose-volume conformation to the target volume compared to the doctor's plan. CONCLUSION: This method converges quickly and is not sensitive to the initial parameters. It achieves an excellent conformation of the estimated isodose curves with the contours of the target volume. If the initial parameters are varied, there will be a little difference in parameters' configuration, but the dosimetric results proved almost to be the same.

Algorithms↗

PubMed1997

17beta-estradiol potently suppresses cAMP-induced insulin-like growth factor-I gene activation in primary rat osteoblast cultures.

Insulin-like growth factor-I (IGF-I) is a key factor in bone remodeling. In osteoblasts, IGF-I synthesis is enhanced by parathyroid hormone and prostaglandin E2 (PGE2) through cAMP-activated protein kinase. In rats, estrogen loss after ovariectomy leads to a rise in serum IGF-I and an increase in bone remodeling, both of which are reversed by estrogen treatment. To examine estrogen-dependent regulation of IGF-I expression at the molecular level, primary fetal rat osteoblasts were co-transfected with the estrogen receptor (hER, to ensure active ER expression), and luciferase reporter plasmids controlled by promoter 1 of the rat IGF-I gene (IGF-I P1), used exclusively in these cells. As reported, 1 microM PGE2 increased IGF-I P1 activity by 5-fold. 17beta-Estradiol alone had no effect, but dose-dependently suppressed the stimulatory effect of PGE2 by up to 90% (ED50 approximately 0.1 nM). This occurred within 3 h, persisted for at least 16 h, required ER, and appeared specific, since 17alpha-estradiol was 100-300-fold less effective. By contrast, 17beta-estradiol stimulated estrogen response element (ERE)-dependent reporter expression by up to 10-fold. 17beta-Estradiol also suppressed an IGF-I P1 construct retaining only minimal promoter sequence required for cAMP-dependent gene activation, but did not affect the 60-fold increase in cAMP induced by PGE2. There is no consensus ERE in rat IGF-I P1, suggesting novel downstream interactions in the cAMP pathway that normally enhances IGF-I expression in skeletal cells. To explore this, nuclear extract from osteoblasts expressing hER were examined by electrophoretic mobility shift assay using the atypical cAMP response element in IGF-I P1. Estrogen alone did not cause DNA-protein binding, while PGE2 induced a characteristic gel shift complex. Co-treatment with both hormones caused a gel shift greatly diminished in intensity, consistent with their combined effects on IGF-I promoter activity. Nonetheless, hER did not bind IGF-I cAMP response element or any adjacent sequences. These results provide new molecular evidence that estrogen may temper the biological effects of hormones acting through cAMP to regulate skeletal IGF-I expression and activity.

Animals↗

PubMed1997

Effect of "jia wei fo shou san" on erythrocyte membrane calcium, zinc concentration in pregnant rats with asymmetrical intrauterine growth retardation induced by passive smoking.

Using experimental model of pregnant rats with asymmetrical intrauterine fetal growth retardation induced by passive smoking, the effects of natural herb "Jia Wei Fo Shou San" on erythrocyte membrane calcium, zinc concentration were observed by atomic absorption spectrophotometry. The results showed that the mean fetal birth weight, zinc concentration of erythrocyte membrane were found to be decreased in the model group as compared with the control group (P < 0.01, P < 0.01). On the other hand, the element of calcium onto erythrocyte membrane were higher in model group than that in control group (P < 0.05). These changes were significantly mild in the treated group and were similar to those of the control group (P > 0.05). Furthermore, our findings indicated that the zinc concentration of erythrocyte membrane seems to be positively correlated with the birth weight (P < 0.01). Calcium composition of red cell membrane showed a significant negative relation to the birth weight (P > 0.05). Our results provided an experimental evidence that normal concentrations of calcium and zinc onto erythrocyte play an important part in fetal growth. One of the mechanisms of "Jia Wei Fo Shou San" in improving fetal growth may have something to do with modulation of erythrocyte calcium, zinc element, thereby protecting bio-functions of erythrocyte and promoting blood circulation.

Animals↗

PubMed1997

Effect of egg size and strain and age of hens on the solids content of chicken eggs.

A study was conducted to determine the effect of egg size and the age and strain of hens on the content of egg solids. Eggs were obtained from commercial farms from four strains of hens with similar age groups and received diets formulated to contain the same dietary energy and protein levels across the strains within a farm. Eggs were collected on 2 different d when the flocks reached the average ages of 28, 55, 75, and 97 wk. The eggs collected form each farm were pooled and sorted by size. Each individual egg was used as a replicate for yolk:white ratio; however, five yolks, five whites, and five whole eggs from each strain at each age period were pooled, homogenized, and then used as a replicate to determine the solids contents of yolk, white, and whole eggs. The yolk:white ratio of eggs from 28-wk-old hens was the lowest, that from 55- and 78-wk-old hens was the highest, and that from 97-wk-old hens was intermediate; however, the solids content (percentage) of whole eggs increased with the age of the hens. The solids content of egg white was highest in eggs from 28-wk-old hens. The white solids content of extra large eggs was greater than that of medium eggs, and yolk solids increased with egg size; however, the solids of whole egg were not affected by egg size. The strain of hens had a significant effect on the solids of whole egg, white, and yolk; however, the strain effect on yolk:white ratio was not significant. The results showed that young (28-wk-old) and old birds (97-wk-old) produced eggs with low solids content and intermediate aged hens (55- to 78-wk-old) produced eggs with high solids content. Therefore, it may be more beneficial for egg producers and processors to use young (28-wk-old) and old birds (97-wk-old) for table egg production and birds of intermediate age (55- to 78-wk-old) for liquid egg production.

Aging↗

PubMed1997

[Effect of recombinant growth hormone on amino acids metabolism in blood and urine after major operation].

To determine the effects of recombinant human growth hormone (GH) on postoperative amino acids metabolism, we performed a placebo-controlled randomized double-blind trial in 18 patients after elective gastrectomy or colectomy. The same amount of calories and amino acids were administered. Research group was daily injected growth hormone 0.15 IU/(kg.day) and control group was given placebo during the first postoperative week. All urine were analyzed for nitrogen balance and excretion of 3-methylhistidine. On the seventh postoperative day while the parenteral nutrients were being infused, amino acid exchange across the forearm was measured. On the seventh postoperative day all patients' amino acids in plasma were slightly increased by comparing with preoperative day but was not statistical significance. Forearm arterial-venous difference (A-V) measured on POD + 7 was markedly different between groups. There was continued release of amino acids from the forearm in the control subjects, while there was marked amino acid uptake in the GH patients (total amino acid nitrogen exchange was -398 +/- 158 mumol/L vs +165 +/- 61 mumol/L, P < 0.01). Excretion of urinary 3-methylhistidine in control group loss more than in GH group (7.3 +/- 1.0 mumol/(kg.24 h) vs 4.4 +/- 0.3 mumol/(kg.24 h), P < 0.05). The results demonstrated that GH can increase the uptake of amino acid from forearm and decrease the excreation of 3-methylhistidine in urine after operation, but did not disturb the balance of amino acids in plasma.

Amino Acids, Branched-Chain↗

PubMed1996

Identification of the cAMP response element that controls transcriptional activation of the insulin-like growth factor-I gene by prostaglandin E2 in osteoblasts.

Insulin-like growth factor-I (IGF-I), a multifunctional growth factor, plays a key role in skeletal growth and can enhance bone cell replication and differentiation. We previously showed that prostaglandin E2 (PGE2) and other agents that increase cAMP activated IGF-I gene transcription in primary rat osteoblast cultures through promoter 1 (P1), the major IGF-I promoter, and found that transcriptional induction was mediated by protein kinase A. We now have identified a short segment of P1 that is essential for full hormonal regulation and have characterized inducible DNA-protein interactions involving this site. Transient transfections of IGF-I P1 reporter genes into primary rat osteoblasts showed that the 328-base pair untranslated region of exon 1 was required for a full 5.3-fold response to PGE2; mutation in a previously footprinted site, HS3D (base pairs +193 to +215), reduced induction by 65%. PGE2 stimulated nuclear protein binding to HS3D. Binding, as determined by gel mobility shift assay, was not seen in nuclear extracts from untreated osteoblast cultures, was detected within 2 h of PGE2 treatment, and was maximal by 4 h. This DNA-protein interaction was not observed in cytoplasmic extracts from PGE2-treated cultures, indicating nuclear localization of the protein kinase A-activated factor(s). Activation of this factor was not blocked by cycloheximide (Chx), and Chx did not impair stimulation of IGF-I gene expression by PGE2. In contrast, binding to a consensus cAMP response element (CRE; 5'-TGACGTCA-3') from the rat somatostatin gene was not modulated by PGE2 or Chx. Competition gel mobility shift analysis using mutated DNA probes identified 5'-CGCAATCG-3' as the minimal sequence needed for inducible binding. All modified IGF-I P1 promoterreporter genes with mutations within this CRE sequence also showed a diminished functional response to PGE2. These results identify the CRE within the 5'-untranslated region of IGF-I exon 1 that is required for hormonal activation of IGF-I gene transcription by cAMP in osteoblasts.

Animals↗

PubMed1996

Effect of huoxuequyu recipe on erythrocyte ultrastructure and membrane ATPase activity in rats with passive smoking.

The effect of "Huoxuequyu" recipe on erythrocyte membrane Ca(2+)-ATPase activity, Na(+)-K(+)-ATPase activity and erythrocyte ultrastructure in rats exposed to passive smoking were observed. The erythrocyte membrane Ca(2+)-ATPase activity and Na(+)-K(+)-ATPase activity were found to be decreased in the model group as compared with the control group (P < 0.01, P < 0.01), while no significant difference existed between the treated group and the control group (P > 0.05). Our results also showed that there were more deformed red blood cells in model group than in control group under TCM and SEM (P < 0.0001). No significant difference was found between control group and treated group (P > 0.05). Furthermore, these findings indicated that "Huoxuequyu" recipe, a prepared natural herbal medicine, may be involved in modulation of the activity of erythrocyte membrane enzymes, thereby protecting erythrocyte membrane, so as to improve the erythrocyte function.

Adult↗