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Biomedical subjects

W J Yang

Publications and source records attributed to W J Yang.

At least 19 recordsLinked to original sources
PubMed2003

Apparent ileal digestibility of amino acids and the digestible and metabolizable energy content of high-oil corn varieties and its effects on growth performance of pigs.

Two experiments were conducted to compare the nutritional value of normal and high-oil corn for pigs. The normal corn and the two varieties (high-oil corns A and B) of high-oil corn contained 4.41, 7.35 and 8.86% ether extract, on DM basis, respectively. In experiment 1, six non-littermate crossbred barrows (37.8 +/- 1.3 kg BW) were fitted with ileal T-cannulas and used in a double replicated Latin Square digestion trial. Three diets were formulated containing 96.6% of one of the three varieties of corn as the only protein source. Chromic oxide (0.4%) was added as a digestibility marker. Additional vitamins and minerals were added to meet requirements. The digestible energy concentrations for normal corn and high-oil corn A and B were 16.53, 16.99 and 17.07 MJ/kg while the metabolizable energy values were 15.82, 16.32 and 16.36 MJ/kg, on DM basis, respectively. The ileal amino acid digestibility of high-oil corn was generally higher than that of normal corn with significant differences being observed for the essential amino acids isoleucine and phenylalanine. In experiment 2, 96 pigs (8.01 +/- 0.14 kg BW) were used to evaluate four diets in a 2 x 2 factorial design conducted over a 35-day period. Corn variety (high-oil vs. normal corn) and nutrient density (high content of protein and ME vs. low content of protein and ME) were set as the two main effects. During the first 14 days, pigs fed high-oil corn diets consumed more feed and tended to get higher daily gain than pigs fed normal corn. Over the entire 35-day experiment, increasing dietary nutrient density increased daily gain and tended to increase feed conversion, while variety of corn had no significant effects on performance. Overall, the present results indicate that the energy concentration and ileal amino acid digestibility of high-oil corn varieties were equal or superior to those in normal corn and therefore they should be able to be effectively utilized in diets fed to swine.

Amino Acids↗
PubMed2001

Cloning of precursors for two MIH/VIH-related peptides in the prawn, Macrobrachium rosenbergii.

Two cDNA clones (634 and 1366 bp) encoding MIH/VIH (molt-inhibiting hormone/vitellogenesis-inhibiting hormone)-related peptides were isolated and sequenced from a Macrobrachium rosenbergii eyestalk ganglia cDNA library. The clones contain a 360 and 339 bp open-reading frame, and their conceptually translated peptides consist of a 41 and 34 amino acid signal peptide, respectively, and a 78 amino acid residue mature peptide hormone. The amino acid sequences of the peptides exhibit higher identities with other known MIHs and VIH (44-69%) than with CHHs (28-33%). This is the first report describing the cloning and sequencing of two MIH/VIH-related peptides in a single crustacean species. Transcription of these mRNAs was detected in the eyestalk ganglia, but not in the thoracic ganglia, hepatopancreas, gut, gill, heart, or muscle.

Amino Acid Sequence↗
PubMed2001

Changes in free amino acids in the hemolymph of giant freshwater prawn Macrobrachium rosenbergii exposed to varying salinities: relationship to osmoregulatory ability.

Changes in free amino acids (FAA) in the hemolymph of the giant freshwater prawn, Macrobrachium rosenbergii, were examined in individuals exposed to varying salinities for up to 1 week. In freshwater and under conditions of low salinity, total FAA concentrations were maintained between approximately 0.85 and 1 mM and did not exhibit changes in response to salinity exposure. Under high salinities, total FAA concentrations increased dramatically, reaching up to 2.1 mM depending on treatment. Examination of individual amino acid concentrations revealed that these increases were based on specific changes in glycine, arginine, alanine, proline and lysine. Among these, alanine showed the greatest increases, resulting in levels six-fold higher under high salinity than in freshwater and under low salinity. The other amino acid species showed increases of 2.5-fold compared to original values. These five FAAs in freshwater and under low salinity together occupied approximately 45% of total FAA contents and under high salinity comprised more than 70% of total FAA contents. These results suggest that specific hemolymph FAAs are involved in mediating response to salinity exposure in freshwater prawns.

Amino Acids↗
PubMed2001

Urethral diverticulo-rectal fistula in AIDS.

A 41-year-old heterosexual African man was evaluated for persistent urethral discharge, pneumaturia and watery diarrhea. Radiographic and endoscopic procedures established the diagnosis of a rectourethral fistula. The differential diagnosis of an acquired rectourethral fistula and the significance of AIDS are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Determination of amino acid sequence and site of mRNA expression of four vitellins in the giant freshwater prawn, Macrobrachium rosenbergii.

Four major yolk proteins, designated as vitellins (Vns) Macr-VnA, B, C, and D, were extracted from mature ovaries of Macrobrachium rosenbergii. These were purified to homogeneity by reversed-phase high performance liquid chromatography (HPLC) employing a unique separation system based on the hydrophobic properties of the Vn molecule. Using standard techniques of protein sequencing, more than 33 N-terminal and 57 internal amino acid residues were determined for each of the four Vns. The cDNA fragments encoding the four Vns were amplified by PCR using degenerate oligonucleotide primers derived from the N-terminal and internal amino acid sequences. These cDNA fragments were cloned, sequenced, and used as probes to examine the transcription of mRNAs encoding the four Vns. Significant accumulations of these mRNAs were observed in female hepatopancreas only, while mRNA expression was not detected in male hepatopancreas or any other female tissue including ovary, subepidermal adipose tissue, gill, and muscle. This is the first occasion in Crustacea in which multiple Vns were demonstrated to be synthesized simultaneously in a single tissue.

Amino Acid Sequence↗
PubMed2000

Characterization of Na/K-ATPase in Macrobrachium rosenbergii and the effects of changing salinity on enzymatic activity.

A ouabain-sensitive Na/K-ATPase kinetic assay system based on the hydrolysis of ATP and the oxidation of NADH was adapted in order to characterize enzymatic activity in gills and examine the effects of changing salinity in Macrobrachium rosenbergii. Maximum inhibition by ouabain occurred at a concentration of 1.4 mM, and the K(m) of the reaction was 0.2 mM. In a first experiment, animals were acclimated to freshwater, 1/3 seawater, 2/3 seawater and full seawater for up to 1 week. Na/K-ATPase activity in front gills was 1. 62+/-0.19 micromol ADP/mg protein per h in freshwater, and was seen to increase slightly in 1/3 seawater (1.88+/-0.19 micromol ADP/mg protein per h) and 2/3 seawater (2.09+/-0.24 micromol ADP/mg protein per h), decreasing slightly in full seawater (1.92+/-0.43 micromol ADP/mg protein per h); however, differences were not significant. Back gills showed slightly higher levels, and a similar pattern of Na/K-ATPase activity. In a second experiment, animals were acclimated to 1/3 seawater and 2/3 seawater, and then transferred to freshwater. However, no changes in activity were seen, indicating that exposure to dilute media did not effect enzymatic activity. Whereas Na/K-ATPase is important in osmoregulatory function in marine euryhaline crustaceans, it may not play a significant role in adaptation in freshwater crustaceans that inhabit a more narrow range of salinities.

Adenosine Diphosphate↗
PubMed2000

Penile vibratory threshold changes with various doses of SS-cream in patients with primary premature ejaculation.

SS-cream made with extracts from natural products is a topical agent for treating premature ejaculation (PE). In order to elucidate the penile vibratory threshold changes and clinical effects of various doses of SS-cream, 53 patients with primary PE were investigated in a double-blind randomized placebo-controlled study. The mean age was 37.3 +/- 6.4 years and mean ejaculatory latency was 1.37 +/- 0.52 minutes. Neither the patients nor their sexual partners were satisfied with their sexual lives. Vibratory threshold at the glans penis, penile shaft, scrotum and index finger were measured using a biothesiometer twice during the screening period and three times one hour after the application of respective creams (SS-cream 0.05, 0.10. 0.15, 0.20 gm and placebo 0.10 gm) on the glans penis according to the order of the allocation table in a randomized fashion. The efficacy of SS-cream was defined as when the vibration threshold increased by more than 4 microns compared to the value tested during the screening period. The vibratory thresholds at the glans penis increased significantly in a dose-dependent manner after the application of various doses (0.05, 0.10, 0.15, 0.20 gm) of SS-cream (p < 0.001), and the efficacy of SS-cream on the penile vibration threshold increased according to the increased dosage (penile shaft: 48.4, 51.6, 54.8, 64.5%, glans penis: 58.1, 67.7, 77.4, 83.9%, respectively). With these results, we concluded that SS-cream increased the penile sensory threshold dose dependently, and therefore it is clinically effective for treating the heightened penile sensory response in patients with PE.

Adult↗
PubMed2000

[Studies on response characteristics of Cl, Br, I of microwave plasma torch atomic emission detector for gas chromatography].

The present paper deals with a microwave plasma torch atomic emission detector for gas chromatography. Argon is used as support gas, carrier gas and make-up gas. The effect of oxygen scavenger gas on the detection performance for chlorine, bromine and iodine is discussed. Detection limits, dynamic ranges, relative standard deviations and response characteristics of GC-MPT-AED for chlorine, bromine and iodine in organic compounds were studied. The results are favorable in comparing with GC-ICP-AED.

Bromides↗
PubMed1999

Lysozyme association with nucleic acids.

Lysozyme is well known for the ability to hydrolyze the cell wall of bacteria. Based on the similarity of structure between lysozyme and histones as seen from the results of X-ray crystal structure determinations, we have postulated that binding to nucleic acids may be another biological function of lysozyme. We have therefore begun a systematic study of the interactions of lysozyme and related molecules with nucleic acids, and present here a preliminary report. Binding to DNA and RNA has been demonstrated from gel electrophoresis, enzyme activity, and coprecipitation studies. We suggest that this function of lysozyme will provide an explanation why Lee-Huang et al. (1999) [Proc. Natl. Acad. Sci. USA 96, 2678-2681] were able to call lysozyme a "killer protein" against the AIDS virus, and may provide a new avenue of research on AIDS therapy.

Animals↗
PubMed1999

Characterization of chromatophorotropic neuropeptides from the kuruma prawn Penaeus japonicus.

Three chromatophorotropic neuropeptide hormones were purified from an aqueous extract of the sinus glands of the kuruma prawn Penaeus japonicus by two steps of reverse-phase HPLC and their amino acid sequences determined. One of them was found to show pigment concentrating activity and to have an amino acid sequence identical with that of the known red pigment concentrating hormone (RPCH), and therefore it was named Pej-RPCH. The other two peptides showed pigment dispersing hormone (PDH) activity and were named Pej-PDH-I and -II. They both consisted of 18 amino acid residues with a free amino-terminus and an amidated carboxyl-terminus, the sequences of Pej-PDH-I and -II being NSELINSLLGIPKVMTDAamide and NSELINSLLGLPKFMIDAamide, respectively. Three amino acid residues at positions 11, 14, and 16 differed between the two PDHs. Pej-PDH-II was about 5-, 7-, and 10-fold more potent than Pej-PDH-I for erythrophores, xanthophores, and melanophores, respectively. The major reason for the difference in potency between the two PDHs was attributed to differences in residues at position 16. In addition, they were found to be produced by a single individual. The order of sensitivity of the four types of chromatophores to Pej-RPCH and both PDHs was found to be erythrophores = xanthophores > melanophores > leukophores.

Amino Acid Sequence↗
PubMed1999

Population distributions of allele frequency of apolipoprotein E by age and gender in Han Chinese.

AIM: To study apolipoproteins E (ApoE) allele frequency in Han Chinese based on age and gender from Shanghai metropolitan area. METHODS: Healthy Han Chinese people (F: 237 and M: 412) were involved in this study. ApoE gene was amplified by PCR using the forward primer: 5'-GGC ACG GCT GTC CAA GGA GCT-3' and reverse primer: 5'-GAT GGC GCT GAG GCC GCG CT-3'. The PCR product was digested directly with 5 units of CfoI and separated by a 20% polyacrylamide nondenaturing gel. RESULTS: ApoE*3 was the commonest allele which accounted for 86.4% of the isoforms, and ApoE*2 and ApoE*4 accounted for 6.2% and 7.5%, respectively. The allele and genotype frequencies were in Hardy-Weinberg equilibrium by comparison with that of the corresponding theoretical distribution (P > 0.05). CONCLUSION: The frequencies of ApoE*2, ApoE*3, and ApoE*4 were demonstrated in the normal Chinese population.

Adult↗
PubMed1998

Gene synthesis by a LCR-based approach: high-level production of leptin-L54 using synthetic gene in Escherichia coli.

Synthetic genes are very useful in genetic and protein engineering. Here we propose a general method for construction of synthetic genes. Short oligonucleotides are joined through ligase chain reaction (LCR) in high stringency conditions to make "unit fragments" which are then fused to form a full-length gene sequence by polymerase chain reaction. The procedure is simple and accurate and does not place constraints on sequence and length. In this report, a recombinant leptin gene was synthesized according to the codon preference of Escherichia coli. Besides, a substitution of the only Met at position 54 for Leu and an addition of a Met at the N-terminus were introduced in the synthetic gene. The gene was cloned in the pQE-31 expression vector and was expressed in E. coli. A large amount of recombinant leptin containing 6 x His tag was produced and purified by Ni-NTA affinity column. Finally, intact leptin-L54 was released after removing the tag by CNBr cleavage at the Met residue.

Animals↗
PubMed1997

Amino acid sequences and activities of multiple hyperglycemic hormones from the Kuruma prawn, Penaeus japonicus.

By means of a single-step reversed-phase HPLC, six CHH family peptides were isolated from sinus gland extracts of the kuruma prawn, Penaeus japonicus. Five of these peptides (Pej-SGP-I, -II, -III, -V, and -VI) expressed hyperglycemic activity and were considered to be the hyperglycemic hormones of this prawn. The amino acid sequences of the five peptides were determined (the amino acid sequence of Pej-SGP-III had been previously determined), revealing that all consisted of 72 amino acid residues with a free amino-terminus and an amidated carboxyl-terminus. They showed considerable sequence similarity to one another, but much less similarity to Pej-SGP-IV with molt-inhibiting activity, the sequence of which had also been determined previously. Examination of the dose-response relationship of these peptides showed that they were equally potent but had different efficacies, which were in the order of Pej-SGP-V, -VI > -III, -I > -II, corresponding well with their sequence characteristics.

Amino Acid Sequence↗
PubMed1997

The efficacy of intrathecal coadministration of morphine and bupivacaine for labor analgesia.

BACKGROUND: Intrathecal (i.t.) opioids can provide labor analgesia, but the onset of pain relief is slow. Bupivacaine has the beneficial property of less motor blockade than other local anesthetics. This study retrospectively examined the efficacy of concomitant use of i.t. morphine and bupivacaine for labor pain relief. METHODS: Fifty five nulliparas who requested analgesia in the active phase (IA group) prior to a cervical dilation 3.9 +/- 0.6 cm and received i.t. morphine 0.5 mg and 0.1% bupivacaine 2.5 mg served as the treatment group, and 88 similar nulliparas who did not request and receive analgesia served as the control group. RESULTS: The mean onset time of analgesia was 2.6 +/- 0.5 min, the duration was 4-12 h and 93% of parturients did not request additional analgesia after a single injection of i.t. morphine and bupivacaine. The active phase of the first and second stages of labor in the treatment group were significantly longer [318 +/- 214 min vs. 176 +/- 120 min; 74 +/- 29 min vs. 37 +/- 26 min]. Frequency of instrument-assisted vaginal delivery was higher compared with the control group (30.9% vs. 14.1%). However, there were no significant differences in the rate of cesarean section and the Apgar scores of newborns at 1 min and 5 min between the treatment and control group. The major side effects of the treatment group included pruritus (48%), nausea (40%), vomiting (37%), somnolence (27%), shivering (27%), urinary retention (21%), hypotension (15%), and bradycardia (13%). Most of the side effects were mild and could be alleviated by naloxone. Neither post-spinal headache nor respiratory depression was noted. CONCLUSIONS: Our results showed that a single injection of i.t. morphine and bupivacaine provided rapid onset and effective analgesia with manageable side effects and without major complications. Thus, i.t. morphine and bupivacaine provides an alternative to epidural analgesia for most women in labor.

Adult↗
PubMed1996

Amino acid sequence of a peptide with molt-inhibiting activity from the kuruma prawn Penaeus japonicus.

Six major peptides (Pej-SGP-I-VI) that belong to the CHH family have been isolated from the sinus gland extracts of the kuruma prawn Penaeus japonicus. By in vitro assay using the Y-organ of the crayfish Procambarus clarkii, Pej-SGP-IV was found to be active in inhibiting ecdysteroid synthesis. We determined the complete amino acid sequence. Pej-SGP-IV consists of 77 amino acid residues, with both free aimno- and carboxyl-termini. The sequence of Pej-SGP-IV shows considerable similarity to that of MIH of the shore crab Carcinus maenas and less similarity to Pej-SGP-III, whose sequence has been previously determined.

Amino Acid Sequence↗
PubMed1996

Relationship between velopharyngeal dimensions and palatal EMG during progressive hypercapnia.

To examine the contribution of specific palatal muscles to velopharyngeal dimensions, we recorded electromyographic (EMG) activity in the levator veli palatini, the tensor veli palatini, and the palatoglossus while examining the velopharynx (VP) with videoendoscopy in eight awake normal adults. Simultaneous display of VP images and airflow provided precise timing of events. Video images and EMG signals were recorded during progressive hypercapnia. Every tenth breath was analyzed. For each selected breath, VP area, anteroposterior and lateral diameters, and EMG activity were determined at five points: beginning, middle, and end of inspiration and middle and end of expiration. VP measurements changed significantly during the respiratory cycle. Although maximum area was measured at end inspiration or middle expiration and minimum area at the beginning or end of the breath, respiratory-related changes in VP measurements and EMG activity were characterized by substantial inter- and intrasubject variability. This variability is similar to velopharyngeal behavior during nonrespiratory tasks and suggests that upper airway patency is determined by multiple factors.

Adult↗