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Biomedical subjects

Y Han

Publications and source records attributed to Y Han.

342 records · Page 19Linked to original sources
PubMed1987

Nutritive value of high oil corn for poultry.

Several experiments were conducted to evaluate the nutritional value of high oil corn for poultry relative to that of conventional (CONV) corn. The variety of high oil corn (HO1) evaluated in most trials contained 6.0% oil and 9.6% protein on a 10% moisture basis. The protein quality of HO1 and CONV corn was assessed with female crossbred chicks fed corn as the sole source of dietary protein. There was no difference in either protein efficiency ratio or in net protein ratio between the two types of corn. True metabolizable energy (TME) and nitrogen-corrected TME (TMEn) values of HO1 corn were determined using adult roosters. The TME and TMEn values of HO1 corn were approximately 4.5% higher than those of CONV corn. Two experiments were conducted to evaluate the use of high oil corn varieties, containing from 6 to 13% oil, in practical diets of commercial broiler chicks from 8 to 22 days posthatching. Weight gain, gain-to-feed ratio, and skin and plasma pigmentation were improved in chicks fed 24% protein diets containing high oil corns compared with those fed the same diet containing CONV corn; magnitude of response was highly correlated to oil content of the corn. The relative value of HO1 corn in practical laying hen diets was examined in a 15-wk experiment. Hens fed a 17% protein diet containing HO1 corn from 23 to 38 weeks of age had a better feed-to-egg ratio than those fed the same diet containing CONV corn when the corn sources were substituted on an isonitrogenous basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Lymphatic system of the thyroid gland in the rat.

Intraglandular thyroid lymph vessels in the rat were studied by qualitative and quantitative analyses in order to obtain information regarding their structure, distribution, relationships, and possible mechanisms of lymph formation. Ultrastructurally, the lymphatic vessels were similar to those described in other organs. The volume density of the lymphatic vessels was 0.007, the profile density 5.68 mm2 and the maximum diameter 17.87 nm. Ultrastructurally, visible transport pathways across the vessels appear to be represented by intracytoplasmic vesicles and channels between endothelial cells. The mean maximum diameter of the vesicles was 96 nm and they occupied 6.9% of the cytoplasm. They were equally distributed between luminal, abluminal, and intracytoplasmic positions. Open junctions (greater than 30 nm) were not seen between endothelial cells, but dilations along part of the length of interdigitating and overlapping contacts were frequent. It was concluded that the mechanism of lymph formation in the thyroid is similar to that in the kidney and liver, but differs from that in the dermis or diaphragm. However, the volume density of the vesicles of the thyroid was twice that of the liver and more than twice that of the kidney. This finding is consistent with an increase in transendothelial vesicular transport of macromolecules.

Animals↗
PubMed1985

Prothrombin time proficiency testing: a robust grading method.

A robust two-way analysis of variance technique was applied to determine simultaneously the effects of method and thromboplastin on prothrombin time. A new approach to outlier detection for two-way analysis of variance was used. Focusing on the underlying error structure improved the uniformity of the grading procedure in the hematology proficiency testing program of the New York State Department of Health. The logarithm-transformed scale produced constancy of error variance and resulted in uniformity of the acceptable spread of data. The common variance was lower than that obtained by previous methods and allowed for a narrower acceptable range of reported prothrombin times by reducing the inflated standard deviation, thus improving the efficiency of the grading procedure. For proficiency testing, no advantage was found in the use of either a common thromboplastin or freeze-dried, coumadinized patient plasmas rather than artificially depleted commercial plasmas, except for special purposes.

Automation↗
PubMed1981

Evaluation of preservation methods and solid media suitable for recovery of Ureaplasma urealyticum from transported urine specimens.

Urine specimens to be tested for Ureaplasma urealyticum (T-strain mycoplasma) must often be transported to a central laboratory for identification. To examine survival of these organisms over 2 days of transport, fresh urine samples were tested for the presence of ureaplasmas and then divided into four groups: (i) fresh, (ii) frozen, (iii) preserved with 1% (wt/vol) boric acid at room temperature, and (iv) preserved with 10% dimethyl sulfoxide and frozen. The samples were cultured on both A7 and New York City solid media, and the estimates of survival were compared to that of fresh urine. Less than 10% survival of Ureaplasma was observed in 11 of 14 specimens stored frozen for 2 days without preservation; six specimens lost all organisms. Specimens containing either dimethyl sulfoxide or boric acid showed higher survival rates, although neither method consistently approached the full recovery of the T-strains found with the fresh urine. Ureaplasmas from fresh specimens grew well on both New York City and A7 media; however, the New York City medium proved superior for those preserved with boric acid and for urine samples containing few ureaplasmas. These results indicate that preservation of samples does increase the yield of U. urealyticum from urine samples delayed in transit.

Bacteriological Techniques↗
PubMedDate not supplied

Ultrastructural changes of nucleoli in common wheat induced by actinomycin D.

Common wheat root tip meristematic cells were treated with low concentrations of actinomycin D (ActD), then stained whole by silver nitrate. We showed by transmission electron microscopy that the typical nucleolar structure did not form, but a granular and fibrillar network was exhibited in the nucleolar region. Our results support a correlation between nucleolar organization/assembly and the activation of RNA Polymerase I transcription. Furthermore, we speculate that the fibrillar network present in the nucleolar region of ActD treated cells may represent the basic skeletal structure required to support the nucleolus.

Cell Nucleolus↗
PubMedDate not supplied

Ethanol enhances medial amygdaloid induced inhibition of predatory attack behaviour in the cat: role of GABAA receptors in the lateral hypothalamus.

The present study tested the hypothesis that the suppressive effects of ethanol upon predatory attack behaviour in the cat involve a pathway from the medial amygdala to the lateral hypothalamus, and that these suppressive effects are mediated by gamma-aminobutyric acid (GABAA) receptors located in the lateral hypothalamus. Cannula electrodes were implanted into the lateral hypothalamus for elicitation of predatory attack behaviour and for microinjections of the GABAA receptor antagonist, bicuculline. Monopolar stimulating electrodes were implanted into the medial amygdala from which subseizure levels of electrical stimulation suppressed predatory attack behaviour. In the first phase of the study, we compared response latencies for predatory attack behaviour following single stimulation of the lateral hypothalamus alone with those following paired trials of dual stimulation of the medial amygdala plus lateral hypothalamus. Dual stimulation significantly suppressed predatory attack. In the second phase of the study, peripheral ethanol administration (in doses of 0.01, 0.5 and 1.0 g/kg, i.p.) enhanced the suppressive effects of medial amygdaloid stimulation in a dose- and time-dependent manner in which peak effects were obtained 60 min post-injection. In the third phase of the study, bicuculline (0.15 nmol) was microinjected into the lateral hypothalamus both prior to and following paired trials of dual stimulation. Drug infusion blocked the suppressive effects of medial amygdaloid stimulation upon predatory attack behaviour elicited from the lateral hypothalamus, indicating the importance of GABAA receptors in mediating this suppression. In the fourth phase of the study, bicuculline, microinjected into the lateral hypothalamus at the time when ethanol's effects were maximal (i.e. 60-80 min post-ethanol administration), totally blocked the suppressive effects of medial amygdaloid stimulation as well as the enhancing effects of ethanol upon medial amygdaloid suppression of this form of aggressive behaviour. In the last phase of the study, bicuculline (0.15 nmol) infusion into the lateral hypothalamus significantly reduced the suppressive effects of ethanol (1.0 g/kg, i.p.) upon predatory attack behaviour elicited from the lateral hypothalamus. These results support the hypothesis that ethanol's suppressive effects upon predatory attack behaviour in the cat are mediated, at least in part, by GABAA receptors in the lateral hypothalamus. The present and recent findings in our laboratory support the view that GABAA receptors in the lateral hypothalamus are activated, in turn, by a GABAergic pathway which arises from the medial hypothalamus whose neurons receive inputs from the medial amygdala.

Amygdala↗
PubMedDate not supplied

Protective effects of (-)-epigallocatechin-3-gallate on UVA- and UVB-induced skin damage.

It has been known that green tea and its components possess significant chemopreventive effects against chemical carcinogens and photo-caused skin tumor formation. In this study, the protective effects of (-)-epigallocatechin-3-gallate (EGCG), a major green tea catechin, on the ultraviolet (UV)-induced skin damage (photoaging) were studied in guinea pigs, hairless mice and human dermal fibroblast cultures. The lipid peroxidation was significantly reduced in the EGCG-treated group. The amount of lipid peroxides produced in the control and EGCG treated group were 838 +/- 144 and 286 +/- 57 nmol/mg at 18 h after UV irradiation, respectively. UVB-induced erythema was also significantly reduced in the EGCG treated group. The erythema relative index of the control and the EGCG treated group were 311 +/- 45 and 191 +/- 49 at 16 h after UV irradiation, respectively. EGCG treatment reduced UVA-induced skin damage (roughness and sagginess) and protected from the decrease of dermal collagen in hairless mouse skin. EGCG treatment blocked the UV-induced increase of collagen secretion and collagenase mRNA level in fibroblast culture. The nuclear transcription factors NF-kappaB and AP-1 binding activities were also inhibited by EGCG treatment.

Animals↗
PubMedDate not supplied

Breast cancer screening knowledge, attitudes, and practices among Korean American women.

PURPOSE/OBJECTIVES: To describe the knowledge and beliefs about breast cancer and breast cancer screening and practices of clinical breast examination (CBE) and mammography of Korean American women. DESIGN: Cross-sectional survey. SETTING: Two Korean churches in a mid-sized Southeastern U.S. city. SAMPLE: A convenience sample of 107 Korean women ages 40 and older. METHODS: Data were collected using Champion's Health Belief Model instrument (susceptibility, seriousness, benefits, and barriers) and the Breast Cancer Knowledge test through mailed questionnaires. MAIN RESEARCH VARIABLES: Knowledge and beliefs about breast cancer screening and practices of CBE and mammography. FINDINGS: The percentages of Korean American women who ever had a CBE and mammography were 67 and 58, respectively. Among the Health Belief Model variables, women who never had a CBE had significantly lower knowledge scores and higher perceived barriers to CBE than those who had. Women who never had a mammogram reported significantly higher perceived barriers to mammography. Logistic regression analyses demonstrated that husband's nationality, regular checkups, and encouragement from family members and physicians were significant predictors of CBE and mammography use. CONCLUSIONS: The frequency of breast cancer screening practices among Korean American women is below national objectives. IMPLICATIONS FOR NURSING PRACTICE: As healthcare professionals in a culturally diverse nation, nurses need to increase their awareness of cultural variations and provide culturally and linguistically appropriate breast health education. Additional studies with women from a variety of settings are needed to validate present study findings.

Adult↗
PubMedDate not supplied

Novel N omega-xanthenyl-protecting groups for asparagine and glutamine, and applications to N alpha-9-fluorenylmethyloxycarbonyl (Fmoc) solid-phase peptide synthesis.

The N alpha-9-fluorenylmethyloxycarbonyl (Fmoc), N omega-9H-xanthen-9-yl (Xan), N omega-2-methoxy-9H-xanthen-9-yl (2-Moxan) or N omega-3-methoxy-9H-xanthen-9-yl (3-Moxan) derivatives of asparagine and glutamine were prepared conveniently by acid-catalyzed reactions of appropriate xanthydrols with Fmoc-Asn-OH and Fmoc-Gln-OH. The Xan and 2-Moxan protected derivatives have been used in Fmoc solid-phase syntheses of several challenging peptides: a modified Riniker's peptide to probe tryptophanalkylation side reactions, Briand's peptide to assess deblocking, at the N-terminus and Marshall's ACP (65-74) to test difficult couplings. Removal of the Asn and Gln side-chain protection occurred concomitantly with release of peptide from the support, under the conditions for acidolytic cleavage of the tris(alkoxy)benzylamide (PAL) anchoring linkage by use of trifluoroacetic acid/scavenger mixtures. For each of the model peptides, the products obtained by the new protection schemes were purer than those obtained with N omega-2,4,6-trimethoxybenzyl (Tmob) or N omega-triphenylmethyl (Trt) protection for Asn and Gln.

Amino Acids↗
PubMedDate not supplied

Screening criteria for Chlamydia trachomatis in family planning clinics: accounting for prevalence and clients' characteristics.

The reliability of eight self-reported risk factors as criteria for screening women for Chlamydia trachomatis was evaluated in four family planning clinics in New York State that serve diverse populations. In all, 8,920 women were screened in these clinics; the rates of infection ranged from 2% to 7%. Results of multivariate analyses showed that age was the most important predictor of chlamydial infection in the three clinics where prevalence was 4% or higher; women aged 20-24 were 3-4 times as likely as older women to be infected, and those aged 13-19 were 4-6 times as likely. In these three clinics, screening all women aged 26 or younger (62-80% of the clinic population) would identify about 90% of infected women; in the clinic with the lowest prevalence rate, age was not a reliable criterion. The prevalence of self-reported risk factors varied by clinic, and these factors generally were not reliable indicators of infection. Using the presence of at least one self-reported risk factor as a screening criterion, 80-87% of clinic clients would be screened, and about 90% of infected women would be identified. The presence of clinical signs of chlamydial infection does not increase the reliability of age as a screening criterion.

Adolescent↗
PubMedDate not supplied

Analysis of anxiolytic drugs by capillary electrophoresis with bare and coated capillaries.

The analysis of anxiolytic drugs, including barbiturates and benzodiazepines, by CE with bare and coated capillaries was investigated. Two types of CE modes, capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) were employed for the separation of the solutes. Charged, structurally similar compounds exemplified by hypnotic drugs such as barbiturates were separated by both CZE and MEKC. Optimal separation conditions were established by varying the pH, the concentration of surfactant, the strength of the electric field, and the addition of the organic solvent. CZE provided different selectivities than those obtained by MEKC. For the separation of uncharged compounds such as benzodiazepines, MEKC was the method of choice because the structural difference conferred differences in hydrophobicity, leading to the different interaction with the micelle. Separations by CZE and MEKC with plain, bare fused-silica capillaries were compared to those with C8 and C18 coated capillaries. Although for these solutes, resolution and analysis time were comparable in the three types of capillaries, successful separation of more than 20 kinds of anxiolytic drugs as the mixture was achieved by using C8 and C18 coated capillaries as the separation medium.

Anti-Anxiety Agents↗