PubMed Health⌕ Search

Biomedical subjects

J Chi

Publications and source records attributed to J Chi.

At least 19 recordsLinked to original sources

Characterization of nelfinavir binding to plasma proteins and the lack of drug displacement interactions.

OBJECTIVES: To determine the characteristics of the binding of nelfinavir and active M8 to alpha1-acid glycoprotein (AAG) and human serum albumin (HSA), and to examine the displacement effects of drugs binding extensively to AAG (ritonavir and saquinavir) or to HSA (salicylic acid and valproic acid). METHODS: Free drugs were separated by equilibrium dialysis after incubation with human plasma or purified plasma proteins and after co-incubation with potential displacers. Association constants were estimated from double-reciprocal plots of the data. RESULTS: Nelfinavir and M8 free fractions [fractions of unbound drug (fus)] were 0.42+/-0.08% (mean+/-standard deviation) and 0.64+/-0.07%, respectively. For the two analytes, respectively, association constants were 7.25 x 10(7)/m and 3.33 x 10(7)/m for AAG and 1.11 x 10(6)/m and 7.92 x 10(5)/m for HSA. Nelfinavir fu in an AAG solution was significantly (P < 0.01) increased by the addition of ritonavir or saquinavir, whereas it was unaltered by addition of these drugs to whole plasma. Similarly, fu in an HSA solution was significantly increased (P < 0.01) by the addition of salicylic acid or valproic acid, whereas there was no difference in the free fraction in plasma. CONCLUSIONS: The affinity of nelfinavir for human plasma proteins was higher than that of M8, and both nelfinavir and M8 showed higher affinity to AAG than to HSA. The free fraction of nelfinavir was not affected by drugs that bind extensively to AAG or albumin when these drugs were added to whole plasma in combination, suggesting a compensatory effect of alternate binding proteins.

Binding, Competitive↗

New insights into the karyotypic relationships of Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis).

To investigate the karyotypic relationships between Chinese muntjac (Muntiacus reevesi), forest musk deer (Moschus berezovskii) and gayal (Bos frontalis), a complete set of Chinese muntjac chromosome-specific painting probes has been assigned to G-banded chromosomes of these three species. Sixteen autosomal probes (i.e. 6-10, 12-22) of the Chinese muntjac each delineated one pair of conserved segments in the forest musk deer and gayal, respectively. The remaining six autosomal probes (1-5, and 11) each delineated two to five pairs of conserved segments. In total, the 22 autosomal painting probes of Chinese muntjac delineated 33 and 34 conserved chromosomal segments in the genomes of forest musk deer and gayal, respectively. The combined analysis of comparative chromosome painting and G-band comparison reveals that most interspecific homologous segments show a high degree of conservation in G-banding patterns. Eleven chromosome fissions and five chromosome fusions differentiate the karyotypes of Chinese muntjac and forest musk deer; twelve chromosome fissions and six fusions are required to convert the Chinese muntjac karyotype to that of gayal; one chromosome fission and one fusion separate the forest musk deer and gayal. The musk deer has retained a highly conserved karyotype that closely resembles the proposed ancestral pecoran karyotype but shares none of the rearrangements characteristic for the Cervidae and Bovidae. Our results substantiate that chromosomes 1-5 and 11 of Chinese muntjac originated through exclusive centromere-to-telomere fusions of ancestral acrocentric chromosomes.

Animals↗

A direct determination of thymidine triphosphate concentrations without dephosphorylation in peripheral blood mononuclear cells by LC/MS/MS.

A rapid, sensitive and specific analytical method with minimal sample preparation for the measurement of thymidine triphosphate (TTP) in peripheral blood mononuclear cells (PBMC) by LC/MS/MS has been developed. PBMC were separated from whole blood or buffy coat. The analyte and internal standard were extracted from PBMC with 70% methanol (pH 7.2). These extracts after centrifugation were directly injected onto LC/MS/MS without need for any further sample preparation. The calibration curve was linear over the range 0.8-800 ng/ml. Mean inter- and intra-assay coefficients of variation (CVs) over the range of the standard curve were less than 10%. The overall recovery of TTP was 103.5%.

Calibration↗

Incidence of presbycusis of Korean populations in Seoul, Kyunggi and Kangwon provinces.

Presbycusis, a bilateral sensorineural hearing loss caused by changes in the inner ear, is related to multiple factors such as noise exposure and otologic disease. In institute-based studies, we tried to determine the incidence of presbycusis in Korean populations living in Seoul, Kyunggi and Kangwon provinces by gender and age groups. The subjects were people who had visited health promotion centers. Pure tone audiometry was done over 20 years on 6,028 subjects. In a community-based study, the subjects were elderly residents of Kanghwa-do area. There were no obvious factors that could cause hearing impairment in the subjects. For the pure tone audiometry, hearing threshold was obtained by using the six-dimension method. The incidence of presbycusis for subjects aged 65 years and older was 37.8% and 8.3% for > or = 27 dB HL criterion and > or = 41 dB HL criterion, respectively. The incidence increased with age. A statistically significant difference in the hearing threshold was found between men and women aged 65 years or older. No differences were found between the community-based study and the institute- based studies. There was a high incidence (about 40%) of presbycusis among Koreans aged 65 years or older (for > or = 27 dB HL criterion). With an aging population, we anticipate that this report could be used to provide a basic data for the study of presbycusis.

Adult↗

A longitudinal study of orthodontic treatment need in Dunedin schoolchildren.

The Index of Orthodontic Treatment Need (IOTN) was used to assess unmet orthodontic treatment need in 152 13-year-old Dunedin schoolchildren, and to compare the findings with those obtained in the same children 3 years previously. The children were randomly selected from Dunedin schools as 10-year-olds, and had not received orthodontic treatment. Approximately 86 percent of the 13-year-old children had "No-little" need for orthodontic treatment when assessed by the child-assessed Aesthetic Component (AC) and the examiner-assessed AC. Slightly less than half the children had "No-little" need for orthodontic treatment when assessed with the Dental Health Component (DHC). More 10- and 13-year-old children "Needed" orthodontic treatment with the DHC than with the AC. Both the examiner-assessed AC and the DHC assessed significantly fewer 13-year-olds as needing orthodontic treatment than the same children as 10-year-olds. Complete agreement between the grades assigned at 10 and 13 years occurred in 30-43 percent of the children and, in the treatment-need categories, between 53 percent (DHC) and 84 percent (child-assessed AC) of the children. The fall in treatment need over the 3-year period may be due to selection bias, over-sensitivity of the IOTN to mixed dentition traits, or both. Although a number of 10-year-old children were assigned different grades as 13-year-olds, many remained within the same treatment category. The apparent stability of the IOTN to assess treatment need in 10- and 13-year-old children is attributed to the grouping of different occlusal traits in the same treatment-need category, and to the small number of treatment-need categories in each component.

Adolescent↗

Age changes in orthodontic treatment need: a longitudinal study of 10- and 13-year-old children, using the Dental Aesthetic Index.

The Dental Aesthetic Index (DAI) was used to assess the prevalence of unmet orthodontic treatment need in 150 13-year-old schoolchildren in Dunedin, New Zealand, and to compare the findings with those obtained in the same children at 10 years of age. Fewer 13-year-olds (27%) had a "mandatory" need of orthodontic treatment than when they were 10 years old (33%), 20% had "no/little" need for orthodontic treatment, 33% had an "elective" need for treatment and 20% had a "desirable" need for treatment. The fall in DAI scores is attributed to over-sensitivity of the Index to mixed dentition traits. When the individual scores were analysed, only 7% of the 10-year-olds were given the same scores as when they were 13 years old, 52% were given higher scores and 41% were given lower scores. This disagreement between scores was masked to a limited extent by the DAI categories: 49% of the 10-year-olds were assigned to the same DAI category at 13 years of age, 20% to a greater treatment-need category and approximately 30% to a lower treatment-need category. The DAI, in common with other malocclusion indices, is unreliable over time because it is affected by developmental changes in the occlusal traits measured.

Adolescent↗

Neuroendocrine evidence for dopaminergic actions of hypericum extract (LI 160) in healthy volunteers.

BACKGROUND: We studied the effect of a single dose of a formulation of a methanolic extract of Hypericum perforatum (HP), also known as St. John's wort, on plasma concentrations of growth hormone (GH), prolactin (PRL), and cortisol (CORT) in 12 healthy male volunteers. METHODS: Subjects received 9 tablets of the finished product Jarsin 300 and placebo in a double-blind, balanced-order, cross-over design. RESULTS: Following HP relative to placebo, there was a significant increase in plasma GH and a significant decrease in plasma PRL. Plasma CORT levels were unchanged. CONCLUSIONS: Taken together with data from animal experimental studies, the findings suggest that this dose of HP may increase some aspects of brain dopamine function in humans.

Adult↗

Globular domains of agrin are functional units that collaborate to induce acetylcholine receptor clustering.

Agrin, an extracellular matrix protein involved in neuromuscular junction formation, directs clustering of postsynaptic molecules, including acetylcholine receptors (AChRs). This activity resides entirely in the C-terminal portion of the protein, which consists of three laminin-like globular domains (G-domains: G1, G2 and G3) and four EGF-like repeats. Additionally, alternate mRNA splicing yields G-domain variants G2(0,4) with 0- or 4-amino-acid inserts, and G3(0, 8,11,19) with 0-, 8-, 11- or 19-amino-acid inserts. In order to better understand the contributions of individual domains and alternate splicing to agrin activity, single G-domains and covalently linked pairs of G-domains were expressed as soluble proteins and their AChR clustering activity measured on cultured C2 myotubes. These analyses reveal the following: (1) While only G3(8) exhibits detectable activity by itself, all G-domains studied (G1, G2(0), G2(4), G3(0) and G3(8)) enhance G3(8) activity when physically linked to G3(8). This effect is most pronounced when G2(4) is linked to G3(8) and is independent of the order of the G-domains. (2) The deletion of EGF-like repeats enhances activity. (3) Increasing the physical separation between linked G1 and G3(8) domains produces a significant increase in activity; similar alterations to linked G2 and G3(8) domains are without effect. (4) Clusters induced by two concatenated G3(8) domains are significantly smaller than all other agrin forms studied. These data suggest that agrin G-domains are the functional units which interact independently of their specific organization to yield AChR clustering. G-domain synergism resulting in biological output could be due to physical interactions between G-domains or, alternatively, independent interactions of G-domains with cell surface receptors which require spatially localized coactivation for optimal signal transduction.

Agrin↗

Elongated stylohyoid process: a report of three cases.

The stylohyoid process is part of the stylohyoid chain--the styloid process, the stylohyoid ligament, and the lesser cornu of the hyoid bone. The stylohyoid chain is derived from the second branchial arch. Mineralisation of the stylohyoid ligament and ossification at the tip may increase the length of the styloid process. An elongated stylohyoid or styloid process is considered to be the source of craniofacial and cervical pain commonly known as Eagle's syndrome. In some instances the stylohyoid process may be considerably elongated, yet remain asymptomatic. This paper reports three patients with elongated stylohyoid processes discovered incidentally on routine radiographic examination.

Adolescent↗

Induction of gastritis and gastric ulcer in Mongolian gerbils infected with Helicobacter pylori.

OBJECTIVE: To induce the model of Mongolian gerbil infected by Helicobacter pylori (HP) and to observe the changes of the infiltration and the proliferation of inflammatory cells before and after the bactericidal treatment. METHODS: The animal model of HP infection was induced by inoculating the HP strain (American Type Culture Collection) to male Mongolian gerbil MGS/Sea (SPF). Half a month, 1 month and 3 months after inoculation, kill the animals and make HE staining and immunohistochemistry staining of the stomach to observe the pathological changes. RESULTS: The infiltration of a great number of inflammatory cells was observed with the center of the mucosa of pylorus at the second week of HP infection. At the 3rd month of infection, ulcer appeared near the lesser curvature side of the pylorus. On the early stage of infection, the lesion was acute inflammation characterized by the neutrophilic infiltration, and then transformed into the chronic inflammation characterized by the lymphatic infiltration and the wide formation of lymphatic follicles. CONCLUSION: Mongolian gerbil is an ideal and standard animal model of HP infection.

Animals↗

5-CT or DOI augments TRH analog-induced gastric acid secretion at the dorsal vagal complex.

Serotonin (5-HT) interacts with thyrotropin-releasing hormone (TRH) at the dorsal vagal complex (DVC) to augment TRH-induced stimulation of gastric acid secretion. To investigate the 5-HT receptor family involved in the augmentation response, prototypical 5-HT receptor-selective agonists (146 pmol) were coinjected with the TRH analog RX-77368 (RX; 12 pmol) into the rat DVC in a 30-nl volume. The DVC coordinates were 0.2 mm anterior, 0.2 mm right, 0.6 mm ventral with respect to the calamus scriptorius. Coinjection of RX with the 5-HT agonists 5-carboxyamidotryptamine (5-CT) or (+/-)-1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride (DOI; 5-HT2 agonist) produced a 183 or 103% increase in gastric acid output compared with the RX injection alone. In contrast, coinjection of 2-methyl-5-HT (5-HT3 agonist) with RX produced no effect on RX-induced increase in gastric acid secretion. Moreover, coinjection of SC-53116 (5-HT4 agonist) decreased the gastric acid output by 45% compared with the RX response itself. Examination of the RX/5-HT agonist coinjection response in more rostral regions of the DVC using the same doses (5-CT/RX or DOI/RX) revealed that only 5-CT was effective in producing the augmented response to TRH analog. The results suggest that activation of 5-CT- or DOI-sensitive receptors augments, and of 5-HT4 receptors inhibits, the gastric acid response to TRH analog injected into the DVC. Thus the integrated response to several serotonin receptor subtypes may mediate changes to the TRH response induced by 5-HT at the DVC.

Amphetamines↗

Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type 2 diabetes.

Chromium is an essential nutrient involved in normal carbohydrate and lipid metabolism. The chromium requirement is postulated to increase with increased glucose intolerance and diabetes. The objective of this study was to test the hypothesis that the elevated intake of supplemental chromium is involved in the control of type 2 diabetes. Individuals being treated for type 2 diabetes (180 men and women) were divided randomly into three groups and supplemented with: 1) placebo, 2) 1.92 micromol (100 microg) Cr as chromium picolinate two times per day, or 3) 9.6 micromol (500 microg) Cr two times per day. Subjects continued to take their normal medications and were instructed not to change their normal eating and living habits. HbA1c values improved significantly after 2 months in the group receiving 19.2 pmol (1,000 microg) Cr per day and was lower in both chromium groups after 4 months (placebo, 8.5 +/- 0.2%; 3.85 micromol Cr, 7.5 +/- 0.2%; 19.2 micromol Cr, 6.6 +/- 0.1%). Fasting glucose was lower in the 19.2-micromol group after 2 and 4 months (4-month values: placebo, 8.8 +/- 0.3 mmol/l; 19.2 micromol Cr, 7.1 +/- 0.2 mmol/l). Two-hour glucose values were also significantly lower for the subjects consuming 19.2 micromol supplemental Cr after both 2 and 4 months (4-month values: placebo, 12.3 +/- 0.4 mmo/l; 19.2 micromol Cr, 10.5 +/- 0.2 mmol/l). Fasting and 2-h insulin values decreased significantly in both groups receiving supplemental chromium after 2 and 4 months. Plasma total cholesterol also decreased after 4 months in the subjects receiving 19.2 micromol/day Cr. These data demonstrate that supplemental chromium had significant beneficial effects on HbA1c, glucose, insulin, and cholesterol variables in subjects with type 2 diabetes. The beneficial effects of chromium in individuals with diabetes were observed at levels higher than the upper limit of the Estimated Safe and Adequate Daily Dietary Intake.

Adult↗

[Chemical constituents of the leaves of Ginkgo biloba].

Four compounds were isolated from ethyl acetate extract of the leaves of Ginkgo biloba. Compounds II, III, IV were identified as ginkgolides A, B and C respectively, Compound I, which was obtained from the leaves of G. biloba for the first time, was identified as 3,3'-dimethoxy-4,4'-dihydroxy-stilbene by spectroscopic methods.

Diterpenes↗

Predictive factors for early menarche in Taiwan.

The rapid increase of breast cancer in Taiwan has prompted the authors to evaluate the predictive factors of early menarche among contemporary Taiwanese girls. A total of 895 four-grade girls from eight elementary schools in Taipei City and County were identified as a closed cohort from the first semester of 1993. Data were collected from self-administered questionnaires and school records. A total of 799 girls who had not menstruated in the first year remained in the group through 1994. The effects of potential predictive factors were assessed by logistic regression. Among the 799 girls followed, 69 (8.6%) had first menstruation between the fourth and fifth grades. Height, weight, body mass index and maternal early onset of menarche were positively related to the onset of menarche within the preceding year. Energy consumption during exercise showed only moderate association after being adjusted for age and weight. Calorie intake from junk food was not associated with early menarche within the preceding year. Poor interpersonal family relationships and stressful life events also showed a moderate association with early menarche. The data obtained supported the hypothesis that height, weight, body mass index and maternal early menarche are positive predictive factors of early menarche. The effects of exercise and childhood stress are less prominent.

Age of Onset↗