Biomedical subjects
Publications and source records attributed to D D Feng.
5-n-Pentyl oxadiazole substituted benzenesulfonamide 8 is a potent and selective beta3 adrenergic receptor agonist (beta3 EC50 = 23 nM, beta1 IC50 = 3000 nM, beta2 IC50 = 3000 nM). The compound has high oral bioavailability in dogs (62%) and rats (36%) and is among the most orally bioavailable beta3 adrenergic receptor agonists reported to date.
Benzyl and phenoxymethylene substituted oxadiazoles are potent and orally bioavailable beta3 adrenergic receptor (AR) agonists. The 4-trifluormethoxy substituted 5-benzyl oxadiazole 5f has an EC50 of 8 nM in the beta3 AR agonist assay with 100-fold selectivity over beta1 and beta2 AR binding inhibition activity. Its oral bioavailability in dogs is 30 +/- 4%, with a half-life of 3.8 +/- 0.4 h. In the anesthetized rhesus, 5f evoked a dose-dependent glycerolemia (ED50Gly = 0.15 mg/kg). Under these conditions a heart rate increase of 15% was observed at a dose level of 10 mg/kg.
The recent information explosion has led to massively increased demand for multimedia data storage in integrated database systems. Content-based retrieval is an important alternative and complement to traditional keyword-based searching for multimedia data and can greatly enhance information management. However, current content-based image retrieval techniques have some deficiencies when applied in the biomedical functional imaging domain. In this paper, we presented a prototype design for a content-based functional image retrieval database system for dynamic positron emission tomography. The system supports efficient content-based retrieval based on physiological kinetic features and reduces image storage requirements. This design makes it possible to maintain a large number of patient data sets online and to rapidly retrieve dynamic functional image sequences for interpretation and generation of physiological parametric images, and offers potential advantages in medical image data management and telemedicine, as well as providing possible opportunities in the statistical and comparative analysis of functional image data.
A technique combining wrapping and clipping using a Silastic sheet coated with Dacron mesh is described for treatment of fusiform or broad-based cerebral aneurysms. This sheet is easily tailored to wrapping the aneurysm base while avoiding involvement of the cranial nerves or branching vessels. The sheet is semitransparent so that the caliber of the newly constructed parent artery is easily adjusted during wrap-clipping. After the aneurysm and the parent artery have been circumferentially wrapped with the sheet, aneurysm clips are applied on the sheet so that the base of the aneurysm is clipped between the two leaves of the sheet. This wrap-clipping technique avoids the risks involved in extracting the aneurysm from the parent artery. The Dacron mesh coating the outer surface and sufficient clip closing pressure are both helpful in preventing the clip blades from sliding. Similar previously reported techniques are reviewed and discussed in detail.
The effects of low-dose estrogen and progestogen on menopausal symptoms were studied with Kuppermen score and urinary excretion of calcium as fasting morning urine Ca/Cr ratio in 69 perimenopausal women. The subjects were divided into 3 groups: amenorrhea less than 1 year (14 women); post menopause 1-3 years (19); and post menopause more than 3 years (36). Fasting urine Ca/Cr ratio in the post menopause 1-3 years group was 0.19 +/- 0.01, significantly higher than that (0.14-0.01) in the amenorrhea less than 1 year group and (0.11 +/- 0.006) the post menopause more than 3 years group. 18 women had 4 patterns of low-dose oral estrogen and progestogen: MPA 2 mg QOD, EE 5 micrograms QD, EE 5 micrograms QOD, and EE 5 micrograms and MPA 2 mg QOD. Each pattern was used in turn for 3 weeks, and discontinued for 2 weeks, then the next pattern started and so on. EE 5 micrograms and MPA 2 mg QOD alternately gave the best results both in improving symptoms and lowering urine Ca/Cr ratio. Seven women given intermittent large dose, namely, EE 50 micrograms every 10 days or premarin 2.5 mg every 7 days had symptoms relieved but inconsistent decrease of urine Ca/Cr ratio.
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Pharmacokinetic and pharmacodynamic effects of a vaginal ring releasing 20 micrograms/day levonorgestrel (L-NOG) have been studied in 15 women. Serum levels of L-NOG, estradiol and progesterone were measured three times a week in a control menstrual cycle and a treatment period of 3 months after the insertion of the first vaginal ring. All control cycles were normal ovulatory. Among the 36 treatment cycles 13 were ovulatory (36%), 5 ovulatory with inadequate luteal function (14%), 14 anovulatory but with marked follicle activity (39%) and 4 anovulatory (11%). In the groups with ovulatory reaction the serum levels of L-NOG showed a decline of 54% of the initial level at the end of the treatment period, calculated according to the linear regression equation of Y = 0.903-0.0142X, while in the groups without ovulation the L-NOG levels were higher and the decline was 24% of the initial level (Y = 1.034-0.0086X). There were distinct individual differences in the levels of L-NOG and ovarian reactions. Marked follicle activity with very high estradiol levels were found in correlation with high L-NOG in 7 treatment cycles, particularly in the B type of reaction (B = anovulatory cycle with marked follicle activity). More intermenstrual bleeding and spotting occurred in the second treatment cycles, particularly in those with anovulatory reactions.
Endocrinological profiles of normal menstrual cycles were studied in 41 Chinese women. Daily serum concentration of luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), estradiol (E2) and progesterone (P) were determined by RIA. Thirty-four cycles were of normal length (26-35 days) and 6 cycles were prolonged up to 40 days with a follicular phase of 22-26 days. One cycle was anovulatory. Cyclical changes of LH, FSH, E2 and P were typical of ovulatory cycles in other populations as reported in the literature. In the normal cycle group the geometric mean of the LH midcycle peak level was 46 IU/1, the FSH peak was 10 IU/1, the preovulatory estradiol peak was 1229 pmol/1 and the progesterone luteal maximum was 50 nmol/1. The pattern of cyclical changes in the prolonged ovulatory cycles was similar to the normal length cycles, except that there were significantly higher levels of LH in both follicular and luteal phases, lower FSH in luteal phase, and lower progesterone in luteal phase. A majority of cycles had a midcycle elevation of prolactin and mean PRL levels in the late luteal phase were higher than those in the follicular phase.
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