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Biomedical subjects

S J Yu

Publications and source records attributed to S J Yu.

18 recordsLinked to original sources
PubMed1994

Cerebrospinal fluid from patients with Parkinson's disease alters the survival of dopamine neurons in mesencephalic culture.

We have previously demonstrated that extracts of striatal tissue from patients with Parkinson's disease (PD) increase the survival of dopamine neurons in mesencephalic cultures relative to striatal extracts from control patients. In the present study, ventricular cerebrospinal fluid (vCSF) from patients with PD, Alzheimer's disease (AD), and age-matched controls was similarly assessed. vCSF samples were separated into > 10-kDa and < 10-kDa fractions. Cultures incubated with the > 10-kDa fractions from PD and AD patients contained 73 and 13%, respectively, more tyrosine hydroxylase immunoreactive neurons than cultures incubated with vCSF from age-matched controls. This trophic activity was positively correlated with the trophic activity present in striatal extracts from the same patients. The < 10-kDa vCSF fractions from all patient groups inhibited culture growth. These data suggest that the trophic environment in the striatum is altered in PD and can be successfully monitored in CSF.

Aged↗
PubMed1990

Expression of CYP1A1 gene in patients with lung cancer: evidence for cigarette smoke-induced gene expression in normal lung tissue and for altered gene regulation in primary pulmonary carcinomas.

The major polycyclic aromatic hydrocarbon inducible-cytochrome P4501A1 gene (CYP1A1) is presumed to be important in pulmonary carcinogenesis and toxicology because its product, the cytochrome P4501A1-dependent (CYP1A1-dependent) monooxygenase, transforms selected xenobiotics (including polycyclic aromatic hydrocarbon procarcinogens in cigarette smoke) to potent carcinogenic metabolites. CYP1A1 messenger RNA (mRNA) expression has not, however, been previously demonstrated in human pulmonary tissue. This report defines CYP1A1 gene expression in normal lung tissue and primary pulmonary carcinoma tissue obtained at thoracotomy from 56 patients with lung cancer. When Northern blot hybridization analyses were performed, 17 of 19 (89%) and zero of five (0%) samples of normal lung tissue from active cigarette smokers and nonsmokers, respectively, expressed the normal 2.8-kilobase CYP1A1 mRNA. In addition, a time-dependent decrease in expression of the CYP1A1 gene was noted in normal lung tissue from individuals who were former smokers, with a decrease in expression occurring as early as 2 weeks following cessation of cigarette smoking. Expression became undetectable in all patients who had stopped smoking more than 6 weeks prior to study. When CYP1A1 gene expression was evaluated in lung cancers, mRNA levels were detectable in one of four (25%) tumors from nonsmokers; two of 24 (8%) tumors from former smokers; and seven of 15 (47%) tumors from cigarette smokers. In addition, an approximately 10-kilobase CYP1A1 RNA species, which was not detectable in normal lung tissue, was observed in five of ten (50%) of the lung cancers that expressed the CYP1A1 gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytochrome P-450 CYP1A1↗
PubMed1989

Altered regulation of the cytochrome P4501A1 gene: novel inducer-independent gene expression in pulmonary carcinoma cell lines.

The cytochrome P450 (CYP) systems catalyze the metabolic transformation of a wide variety of xenobiotics including procarcinogens present in cigarette smoke condensate as well as atmospheric pollutants. The CYP1A1 isoenzyme is of particular interest because it has been implicated as a risk factor in the etiology of lung cancer in heavy cigarette smokers. The identification and expression of the structural CYP1A1 gene in either normal human lung or lung cancer cells has not been reported. Because of its potential significance in human lung cancer, we investigated the expression of the CYP1A1 structural gene in 24 established human lung cancer cell lines including 15 non-small cell (eight adenocarcinomas, three large cell undifferentiated carcinomas, two bronchioloalveolar cell carcinomas, and two squamous cell carcinomas) and nine small cell lung carcinomas. CYP1A1 mRNA was detected in 14 of 15 (93%) of the non-small cell lung carcinoma cell lines examined following 24-hour treatment with benz[a]anthracene (BA) and in nine of 15 (60%) of the non-small cell lines cultured without an inducer in the medium. When the small cell lung cancer lines were evaluated for CYP1A1 gene expression, two of nine (22%) expressed detectable CYP1A1 mRNA in both BA-induced cell cultures and constitutive (control) cultures. A positive correlation was noted between BA-induced CYP1A1 mRNA levels and the corresponding aryl hydrocarbon hydroxylase activity expressed as absolute BA-induced enzyme activity (r = 0.74; P less than .01; n = 24), which further demonstrated that CYP1A1 mRNA expression reflects CYP1A1 enzyme activity in the individual cell lines. These observations represent the first known demonstration of constitutive (non-induced) CYP1A1 gene expression in human cells and suggest altered regulation of the CYP1A1 gene in selected lung cancer cell lines. These human pulmonary carcinoma cell lines, which have documented regulatory defects, could be useful for further identification of the mechanisms associated with CYP1A1 gene regulation.

Adenocarcinoma↗
PubMed1988

Presacral myelolipoma: case report with computed tomographic and angiographic findings.

A rare case of presacral myelolipoma in an otherwise healthy 53 year old man is described. His only complaint was lower abdominal discomfort. Full investigation including computed tomography and angiography revealed a well-delineated, heavily calcified, avascular retrorectal mass adhering to the presacral fascia. Histologically the mass showed a mixture of haemopoietic tissue and mature fat cells. Clinically the absence of symptoms and bone involvement served to distinguish this condition from other more sinister presacral lesions, particularly a chordoma.

Angiography↗
PubMed1986

Cytochrome P-450-dependent monooxygenase activity in the velvetbean caterpillar, Anticarsia gemmatalis Hübner.

The activity of microsomal aldrin epoxidase was observed in various tissues of the last instar larva of the velvetbean caterpillar (Anticarsia gemmatalis Hübner) with the midgut being the most active. Optimum conditions for assaying the enzyme were established. Allelochemicals (monoterpenes, indoles and flavones) and host plants (cowpeas, cotton, peanuts, soybeans and hairy indigo) were found to induce the monooxygenase. Piperonyl butoxide decreased and increased the toxicity of methomyl and methyl parathion, respectively, suggesting that the monooxygenase system of velvetbean caterpillars plays a major role in the detoxification of xenobiotics.

Animals↗
PubMed1984

Microsomal biphenyl hydroxylase of fall armyworm larvae and its induction by allelochemicals and host plants.

Biphenyl was hydroxylated to 4-hydroxybiphenyl by a mixed-function oxidase system from midgut microsomes of fall armyworm (Spodoptera frugiperda) larvae. Optimum conditions for assaying the enzyme were established. The microsomal biphenyl 4-hydroxylase activity increased during larval development and declined in the prepupa. Allelochemicals (monoterpenes, indoles and flavones), drugs (phenobarbital and 3-methylcholanthrene) and host plants were found to induce the hydroxylase. The enzyme was also found to be fairly active in other species such as velvetbean caterpillars, corn earworms, tobacco budworms, mole crickets, American cockroaches and honey bees.

Animal Nutritional Physiological Phenomena↗
PubMed1975

Abnormalities in the microsomal oxidases of the WHO standard reference strain of Musca domestica.

Observations made during biochemical and toxicological studies of the housefly, in which the WHO standard reference (SR) strain was used as a standard, indicated that this strain differs from other strains in certain physiological and toxicological aspects. Experiments are described in which microsomal oxidases prepared from the standard reference strain and several other housefly strains, both susceptible and resistant to insecticides, were compared for heat stability, sensitivity to ionic strength, pH optima, and the spectral characteristics of their cytochrome P-450. In a comparison with 8 strains the SR strain microsomes were more stable at high incubation temperatures (40-47.5 degrees C). Compared to two other strains (NAIDM, susceptible, and Isolan-B, resistant) SR was more stable at low pH and more sensitive to high ionic strength. In spectral comparisons with NAIDM and Isolan-B, SR was found to contain microsomal cytochrome P-450 that differed slightly in its carbon monoxide or octylamine binding spectra. The results suggest that this strain may not provide a suitable reference in studies involving the microsomal oxidases. However, these apparent differences should not reduce the value of the SR stain as a reference in insecticide resistance studies.

Aldrin↗
PubMedDate not supplied

Reproductive patterns of the yak. I. Reproductive phenomena of the female yak.

The reproductive phenomena of 62 multiparous yaks from two grassland areas were investigated. The lengths of oestrus and the oestrus cycle were 12-36 h and 19-21 days respectively. Ovulation occurred 12-36 h after the end of oestrus. The oestrus and conception rates were 85.5% and 94.3%. The duration of pregnancy ranged from 248 to 258 days. The signs of oestrus, pregnancy and parturition, and the changes of the uterus and ovaries during oestrus and pregnancy are described.

Animals↗
PubMedDate not supplied

Reproductive patterns of the yak. II. Progesterone and oestradiol-17 beta levels in plasma and milk just before the breeding season; also during normal and short oestrous cycles.

Concentrations of oestradiol-17 beta and progesterone in plasma and milk of the yak before the first oestrus at the beginning of the breeding season and during normal and short oestrus cycles were measured by radioimmunoassay (RIA). Both oestradiol-17 beta and progesterone were maintained at stable, low levels before the first oestrus. However, oestradiol-17 beta showed a peak, similar to that on the day of oestrus (P > 0.05), about 6 days before the first oestrus and a small progesterone peak was seen 2 days before it. There were three peaks of oestradiol-17 beta in plasma and milk on the day of oestrus [24.57 (SD 11.35) pg ml-1 and 97.84 (SD 26.02) pg ml-1 respectively], and on days 5 and 14 of the cycle. Progesterone levels in plasma and milk were low during oestrus but peaks were seen on day 15 [5.23 (SD 1.02) ng ml-1 and 20.44 (SD 3.64) ng ml-1 respectively]. The patterns of oestradiol-17 beta and progesterone during the short cycle were similar to those during the normal cycle (P > 0.05), but the values were lower. The levels of oestradiol-17 beta and progesterone in milk were about 3 or 4 times higher than those in plasma before the first oestrus, and about 4 or 5 times higher during the normal cycle.

Animals↗
PubMedDate not supplied

Reproductive patterns of the yak. III. Levels of progesterone and oestradiol-17 beta during pregnancy and the periparturient period.

Changes in plasma progesterone and oestradiol-17 beta in yaks during pregnancy and the periparturient period of yaks and in milk during the first month of pregnancy were analysed. The profiles of progesterone were similar for pregnant and non-pregnant yaks within 14 days following oestrus (P > 0.05), but the concentration was significantly higher on day 19 (P < 0.05) and in pregnant yaks tended to increase gradually thereafter. The plasma progesterone decreased rapidly on day 120 (P < 0.05), then increased to reach its maximum of 15.5 (SD 3.74) ng ml-1 on day 210; declined again 20 days before parturition and resumed the same levels at parturition as during mating (P > 0.05). The oestradiol-17 beta levels in plasma and milk increased gradually from day 23 after conception, decreased abruptly on day 60 (P < 0.05), then increased to reach their maximum at parturition of 551.4 (SD 70.86) pg ml-1. The oestradiol decreased again after parturition to the same level as during mating (P > 0.05).

Animals↗