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Biomedical subjects

Y C Lin

Publications and source records attributed to Y C Lin.

At least 253 records · Page 14Linked to original sources
PubMed1990

Effect of gossypol on thyroid hormones in young female rats.

The study was designed to examine the effect of gossypol on thyroid function in young female rats. Forty young Sprague-Dawley female rats were randomly assigned to four treatment groups. The dosages of gossypol acetic acid (gossypol) used for this experiment were 1, 5 and 10 mg/kg body weight/day in 0.5 ml potassium phosphate buffer subcutaneously started from day 34 of age for 15 consecutive days. The control group was treated with vehicle alone. Animals were sacrificed 15 days after gossypol treatment. Blood samples and sera were collected and prepared for measurement of thyroid hormones by radioimmunoassay. The levels of free thyroxine (T4), 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine (reverse T3, rT3) in control rats at age 49 days averaged 55.90 +/- 7.7, 670 +/- 90, and 71.7 +/- 5.7 pg/ml of serum, respectively. Fifteen days after gossypol treatment at 5 and 10 mg/kg/day, the free T4 levels significantly decreased to 21.96 +/- 2.1 and 11.12 +/- 1.5 pg/ml of serum, the T3 levels significantly decreased to 430 +/- 89, 359 +/- 90 pg/ml of serum and the rT3 levels were significantly decreased to 37.20 +/- 7.3, and 24.20 +/- 6.0 pg/ml of serum, respectively. However, the serum levels of free T4, T3 and rT3 in the 1 mg/kg/day of gossypol-treated animals were not significantly different from the controls. Five to 15 days after initiation of gossypol treatment, both body weight gain and food intake appeared to be significantly reduced at 5 and 10 mg/kg/day of gossypol treatment. This trend continued to the end of the 15-day gossypol treatment. The results provide new evidence that gossypol might have exerted its antithyroid function by an unknown mechanism that triggered an interference in body metabolism, thus causing the loss of food intake and body weight gain in young female animals.

Animals↗
PubMed1990

Taenia taeniaeformis: inactivation of metacestodes by gossypol in vitro.

Gossypol, a natural biphenyl compound inhibits Taenia taeniaeformis metacestode development in vivo. In this paper, the direct effect of gossypol on metacestodes was examined. Within 24 hr of incubation at 37 degrees C in greater than or equal to 10(-5) M gossypol, shedding of the tegument from the surface of the metacestodes was observed. There was a significant decrease in [3H]thymidine uptake by T. taeniaeformis in greater than or equal to 10(-5)M gossypol. In addition, NADH lactate dehydrogenase activity of metacestodes was significantly inhibited in greater than or equal to 10(-5) M gossypol. Thus, gossypol has a direct inhibitory effect on T. taeniaeformis metacestodes in vitro.

Animals↗
PubMed1990

Effects of larval tapeworm (Taenia taeniaeformis) infection on reproductive functions in male and female host rats.

This report examined the effects of larval tapeworm infection on the reproductive functions in both male and female host rats. Female rats were matched by age, then randomly assigned to control and treatment groups (infected with larval tapeworms). Estrous cycles were determined by vaginal smear with 95% of the control group exhibiting 4-day normal cyclicity and only 55% of the treated group exhibiting normal cycles. Female fertility was then evaluated for the normally cycling rats based on the percentage of successful matings on the evening of proestrus, number of implantation sites on Day 8 of pregnancy, and number of pups born at term. The normally cycling rats exhibited 96% successful mating, 12.95 +/- 1.80 implantation sites, and 11.20 +/- 1.80 pups born. Five months after larval tapeworm infection, the fertility parameters were decreased to 79%, 9.10 +/- 1.20, and 7.50 +/- 1.50, respectively. The control females were then used in a study of male fertility after larval tapeworm infection employing the same parameters used to test female fertility. At the onset of the study, control groups exhibited 95% successful mating, 12.50 +/- 1.50 implantation sites, and 11.60 +/- 1.60 pups born at full term. After the 5-month infection period, the parameters were substantially reduced to 29%, 6.20 +/- 0.80 implantation sites, and 5.10 +/- 0.80 pups, respectively. Average testosterone concentrations in serum and testis from control male rats were 8.80 +/- 0.95 ng/ml and 3.88 +/- 0.25 ng/mg protein, respectively. After the 5-month infection period, these levels were reduced to 2.47 +/- 0.31 ng/ml and 1.28 +/- 0.12 ng/mg protein, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Inhibitory effect of gossypol on human chorionic gonadotropin (hCG)-induced progesterone secretion in cultured bovine luteal cells.

Inhibitory effects of gossypol on the female reproductive system have been recently reported. This study investigated a possible site of gossypol action on progesterone synthesis. Bovine luteal cells were cultured with hCG and forskolin in the presence or absence of gossypol. At 10 micrograms/ml, gossypol significantly inhibited hCG- and forskolin-stimulated progesterone secretion and intracellular cAMP formation; at 20 micrograms/ml, gossypol completely abolished the stimulative effect of hCG and forskolin. The results suggest that adenylate cyclase may be a site of gossypol action on steroidogenesis of bovine luteal cells.

Animals↗
PubMed1990

Effects of sodium arsenite on the cytotoxicity of bleomycin.

Our present data show that posttreatment with sodium arsenite has no effect on the cytotoxicity of bleomycin (BLM), a radiomimetic agent, in Chinese hamster ovary (CHO) cells, human skin fibroblasts, and HeLa cells. However, pretreatment with sodium arsenite potentiated the cytotoxic effects of BLM in CHO cells. This effect decreased with increasing time interval between the treatments with sodium arsenite and BLM. BLM-inactivating activity was markedly reduced in cells pretreated with sodium arsenite. Furthermore, both arsenite-potentiated BLM cytotoxicity and arsenite-reduced BLM-inactivating activity were abolished by cycloheximide. These results suggest that the potentiation effect of sodium arsenite on BLM cytotoxicity may be due to the decrease of BLM-inactivating activity. In addition, only a slight increase in G2 phase population and no apparent change in intracellular glutathione levels were observed in CHO cells pretreated with sodium arsenite.

Animals↗
PubMed1990

Structure of germ line immunoglobulin alpha heavy-chain RNA and its location on polysomes.

We describe the structure of the major germ line RNA transcribed from unrearranged immunoglobulin alpha heavy-chain genes in immunoglobulin M-expressing cells of the I.29 mu B-cell lymphoma, a cell line capable of switching to immunoglobulin A expression upon lipopolysaccharide treatment. This germ line alpha RNA has a small open reading frame that does not include the C alpha domain, and this RNA appears to be present on polysomes in I.29 mu cells.

Animals↗
PubMed1990

The protein synthesis of human full term placenta cell in monolayer culture system.

Protein synthesis of human placenta from cesarean section was analyzed by SDS gel electrophoresis using full term cell culture system. The qualitative pattern of cytoskeletal proteins before and after culture was also examined. After trypsinization, cytotrophoblasts were cultured for 20 days in the humidified incubator of 5% CO2 in 95% air. The confluency was obtained in 10 days after inoculation. The pattern of SDS-PAGE showed several protein bands including actin (43,000 Da) and desmin (55,000 Da) as major constituents of 12 and 20 day cultures. The significant differences between band appearances in samples before and after culturing were noted. The present results indicated that myosin may not be synthesized in high content, differing from previous observations. Cytoskeletal protein production seemed to be markedly enhanced in the cultured system.

Actins↗
PubMed1990

Right ventricular pressure and ventilatory responses to pulmonary gas embolism.

This study was designed to test the hypothesis that changes in right ventricular pressure (PRV) are responsible in part for the altered breathing frequency (f) during pulmonary gas embolism (PGE). PGE was induced by infusing air into the femoral vein of alpha-chloralose anesthetized dogs. Respiratory flow pattern was recorded and analyzed in relation to PRV changes induced resulting from PGE. The rise of PRV, whether induced by PGE, by pulmonary artery occlusion, or by acute elevation of pulmonary arterial blood flow, was consistently associated with increased f. Breathing frequency rose principally through reduction of expiratory duration (TE). The inspiratory duration (TI) was shortened somewhat and the fractional inspiratory cycle, TI/(TE + TI), increased. The relationships between PRV and f were altered by changes of PRV resulting from the administration of histamine antagonist, by beta-adrenergic blockade, beta-adrenergic stimulation, and by changing pulmonary arterial blood flow. The responses did not occur after bilateral cervical vagotomy. These results demonstrate that f during PGE is partially regulated in response to changes in PRV and is mediated through the vagal afferent.

Adrenergic beta-Antagonists↗
PubMed1989

Effect of gossypol on the thyroid in young rats.

The effect of gossypol on thyroid structure and function was examined. Groups of young male rats were subcutaneously injected daily with 0.2 ml gossypol acetic acid in doses of 1, 5, or 10 mg per kg body weight. Control rats were injected with vehicle only. At the end of the 15-day treatment, there was a dose-dependent decrease in the serum concentrations of thyroid hormones, i.e., free thyroxine, triiodothyronine, and reverse triiodothyronine. Histopathological examination revealed focal degeneration of thyroid follicles after a dose of 1 mg gossypol per kg body weight; widespread follicular atrophy occurred with 5 mg and 10 mg gossypol per kg body weight. The degenerating follicles were lined with discontinuous cuboidal or squamous follicular epithelium, some of which exfoliated into colloid.

Animals↗
PubMed1989

Effect of gossypol and its metabolite on in vitro early development of mouse embryos.

The purpose of this study was to examine the effect of gossypol and its metabolite on early in vitro mouse embryo development. One hundred and thirty-eight excellent quality mouse blastocysts were randomly assigned to five different treatments. Culture media were supplemented with 10% (V/N) normal steer serum. The embryos were cultured at 37 degrees C with an atmosphere of 5% O(2), 5% CO(2) and 90% N(2), and embryo development was examined and recorded at 12-h intervals for 72 h. The percentage of embryos that developed to expanded blastocyst (92%), hatching blastocyst (84%), and hatched blastocyst (76%) stages in control Ham's F-10 media was not different from that of embryos cultured in media containing 0.1 and 5 mug of gossypol; however, none of the embryos treated with 265 ng of gossypol metabolite (GM) developed beyond the blastocyst stage. A substantial decrease in the percentage of embryos reaching hatching blastocyst (29%) and hatched blastocyst (29%) stages was observed in the embryos cultured with 5.3 ng of GM. At both light and electron microscopic levels, the embryos appeared to be affected even by a lower concentration of GM in vitro. Our results suggest that GM has a much greater potency than the parent gossypol in inhibiting the early development of mouse embryos in vitro.

Journal Article↗
PubMed1989

Ethanol and acetaldehyde potentiate the clastogenicity of ultraviolet light, methyl methanesulfonate, mitomycin C and bleomycin in Chinese hamster ovary cells.

Ethanol itself did not induce any apparent chromosome aberrations in Chinese hamster ovary cells. However, posttreatment with ethanol potentiated the chromosome aberrations induced by ultraviolet light (UV), methyl methanesulfonate (MMS), mitomycin C (MMC) or bleomycin (BLM). Chromatid exchanges were predominantly increased in cultures treated with UV, MMS or MMC and then with ethanol, whereas chromosome breaks and chromatid exchange were the major types of aberrations increased in the cultures treated with BLM and ethanol. Posttreatment with acetaldehyde, the major metabolite of ethanol, also potentiated the chromosome aberrations induced by UV, MMS, MMC or BLM. The main types of aberrations potentiated by posttreatment with acetaldehyde were similar to those by posttreatment with ethanol.

Acetaldehyde↗
PubMed1989

Selective vagal postganglionic innervation of the sinoatrial and atrioventricular nodes in the non-human primate.

The distribution of parasympathetic postganglionic nerves to the atrioventricular (AVN) and sinoatrial nodal (SAN) regions was investigated in the non-human primate heart. Eight male monkeys (Macaca fascicularis) weighing 5.5-7.0 kg. were anesthetized (alpha-chloralose, 50 mg/kg and urethane, 500 mg/kg) and instrumented to measure arterial pressure, electrocardiogram, atrial and ventricular electrograms. The cervical vagi were electrically stimulated (20 Hz, 4 V, 2 ms) before and after selective denervation (D) of the AVN and/or SAN. Vagal stimulation was repeated during atrial pacing to assess parasympathetic modulation of AVN conduction. Ablation of parasympathetic pathways to the AVN, accomplished by the disruption of the epicardial fat and surface muscle layer at the junction of the inferior vena cava and inferior left atrium eliminated (P less than 0.01) the dromotropic effects of vagal stimulation without affecting the heart rate response (right vagus, before D, paced: atrial rate 218.0 +/- 6.3, ventricular rate 67.1 +/- 23.7; after D: atrial rate 210.3 +/- 6.4, ventricular rate 210.3 +/- 6.4 beats/min, means +/- S.D.). In sharp contrast, surgical dissection of the fat pad overlying the right pulmonary vein-superior vena cava junction significantly (P greater than 0.01) attenuated negative chronotropic effects of vagal stimulation (left vagus, before D the R-R interval increased by 832.7 +/- 146.4 ms, 209.5% increase; after D 37.4 +/- 18.0 ms, 8.8% increase). These data demonstrate discrete vagal efferent pathways innervate both the SAN and AVN regions of the non-human primate heart.

Animals↗
PubMed1989

Developmental changes in lactate dehydrogenase-X activity in young jaundiced male rats.

This study was designed to examine the testicular maturation in both jaundiced (jj) and nonjaundiced (Jj) male Gunn rats as indicated by the activity of a testis and sperm-specific enzyme, lactate dehydrogenase-X (LDH-X), and serum testosterone levels. Testicular cytosolic LDH-X activity was determined by oxidation of reduced nicotinamide adenine dinucleotide (NADH). Serum testosterone levels were measured by radioimmunoassay (RIA). Testicular LDH-X activity increased rapidly between 30 and 50 days of age in both Jj and jj Gunn rats. LDH-X activity was significantly lower in the jj Gunn rats at 50 and 60 days of age. Testosterone level was significantly lower in the jj Gunn rats at 50 days of age. LDH-X activity and serum testosterone levels were similar for both genotypes at 180 days of age. The delay of testicular maturation in the jaundiced males seems to be due to lower LDH-X activity and serum testosterone levels.

Aging↗
PubMed1989

Practical approaches to scientific presentation.

Oral presentation differs from written presentation in that listening audience has a limited time to comprehend the subject matter. Speakers in scientific meetings use slides to facilitate transfer of information, because methods and results are best explained using drawings, figures, and tables. Schematic drawings, tables, and figures that appear in print usually contain too much detail to suit oral presentation. Presentation slides should allow the audience to grasp the contents quickly. Good slides attract attention, invite retention and cross language barriers. Regardless of language and style used, oral scientific presentation emphasizes information transfer, explanation of complex matters in the simplest possible way, and logical sequence; all of these can and should be learned by every scientist.

Communication↗
PubMed1989

Practical approaches to scientific writing.

Scientific writings represent final products of scientific endeavors. A scientist communicates with others by his or her writings and oral presentations. In most universities, there are no formal courses on scientific writing and presentation. Students learn mostly by trial and error or by individual apprenticeship. This brief article presents a practical approach to writing a journal article, regardless of the language used. Scientific writing, as in any other writings, requires clear and concise expressions. In addition, scientific writing expects authors to (1) organize for quick access to specific sections; (2) describe experiments and findings in sufficient details so that they can be duplicated; (3) interpret data for the readers; and (4) summarize and discuss the significance of results and their relation to existing knowledge. This article will discuss the IMRAD format (Introduction, Methods, Results and Discussion). The focus will be on what should be included in each section of the format.

Language↗
PubMed1988

Antifertility effect of gossypol in male Japanese quail.

Conventionally housed 130-160 g adult male Japanese quail were given gossypol acetic acid (gossypol) im at 25 mg/kg in 0.5 ml of 10% EtOH for 12 and 24 days (Groups 1 and 2), respectively. One day after treatment was terminated they were allowed to mate with laying females individually for 20 days. Fertility was 0% from mating of the Group 1 birds on days 1-2 and increased to 25, 35, 55 and 65% on days 3-6 after cessation of gossypol treatment. At day 11, fertility was 80 vs 84% in controls, whereas hatchability was 70% for both. By comparison, eggs from Group 2 mated quail were infertile for up to 20 days after the termination of gossypol treatment. In a parallel experiment, the percent testes to body weight ratio in control and 7, 14, 21, and 28-day gossypol-treated quail was 2.5, 2.2, 1.8, 0.5, and 0.2%, respectively. In 12 vs 24-day treated birds, 7, 14, 21, and 28 days after gossypol treatment, the ratios were 1.0 vs 0.5%, 2.0 vs 0.8% and 2.8 vs 1.9%, respectively. The decreased fertility and hatachability, and testicular atrophy resulting from gossypol given to male quail was dose-time related. Furthermore, the androgen-dependent cloacal gland was drastically reduced in size by the treatment with gossypol. The mode of action of gossypol in male quail is different than it is in mammals in that the testicular size of mammals remains unchanged with long-term gossypol treatment. It is concluded that quail may be a useful avian animal model for investigating the antifertility effects of gossypol.

Animals↗
PubMed1988

Effect of gossypol on bovine embryo development during the preimplantation period.

The purpose of this study was to evaluate the effect of varying doses of gossypol acetic acid on early bovine embryo development in vitro. One hundred and forty-eight excellent and good quality bovine morulae were randomly cultured in 0, 1.0, 5.0, 10.0, 30.0 mug gossypol acetic acid (GAA) in normal steer serum and Ham's F-10 media. Bovine embryo development was assessed at 12-h intervals for 96 h. Sixty-seven percent of embryos developed in 0 mug GAA to the hatched blastocyst stage, while 43, 19, 4 and 0% had comparable development in 1.0, 5.0, 10.0 and 30.0 mug GAA, respectively. Embryos in 5.0 mug GAA had a delayed development to the blastocyst stage compared to embryos in 1.0 mug GAA. Development time to expanded blastocyst stage was longer for 10.0 mug GAA embryos than 0, and 1.0 GAA-treated embryos. No embryo cultured in 30.0 mug GAA advanced past the morula stage. Final developmental scores were highest for embryos in 0 mug GAA (4.06) and lowest for embryos cultured in 10.0 and 30.0 mug GAA (0.44 and -0.02, respectively). Embryos cultured in higher doses of GAA degenerated sooner than embryos cultured in 0 mug GAA. These data show a dose-dependent detrimental action of GAA on early bovine embryo development and suggest a direct action on the embryo itself.

Journal Article↗