Biomedical subjects

H Wei

Publications and source records attributed to H Wei.

At least 19 recordsLinked to original sources

PubMed2002

Stability and activity of specific antibodies against Streptococcus mutans and Streptococcus sobrinus in bovine milk fermented with Lactobacillus rhamnosus strain GG or treated at ultra-high temperature.

Passive local immunization against dental caries is a promising approach to its prevention, as clinical evidence of active oral or nasal immunization is still limited and controversial. By means of systemic immunization of pregnant cows with a multivalent vaccine, high titres of IgG antibodies against human cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, were produced in bovine colostrum. The purified immune product (IP) of this preparation has a number of anticariogenic properties, such as inhibition of streptococcal adherence to saliva-coated hydroxyapatite and inhibition of glucosyltransferase enzymes. This study investigated whether IP antibodies remained active and functional when added to ultra-high temperature (UHT)-treated milk or to Lactobacillus rhamnosus GG (LGG)-fermented milk stored for an extended time. LGG was chosen because of its widely known health benefits in humans and animals. A commercial UHT toddler's milk was supplemented with IP and stored for 2 months at 5, 21 and 30 degrees C. The antistreptococcal titres in UHT milk did not decline at any temperature during storage, and UHT-IP inhibited the adherence of S. mutans for up to 2 months. This was not the case with UHT toddler's milk without IgG antibodies. Milk was fermented with live LGG cells in the presence or absence of 5% IP. The antistreptococcal titres declined to about 30% of the original titres after storage. Fresh milk alone slightly enhanced streptococcal adhesion but fresh milk with IP inhibited the adherence of S. mutans by over 50%. LGG-positive fermented milk without antibodies also inhibited (P < 0.05) the adhesion by about 40%. In both LGG-fermented and UHT immune milk, the activity of antibodies against cariogenic streptococci was maintained during the expected shelf-life of these products. From the anticariogenic point of view it may be beneficial to add bovine-specific antibodies against mutans streptococci to probiotic LGG-containing milk products.

Animals↗

PubMed2001

Peripheral effects of morphine in neuropathic rats: role of sympathetic postganglionic nerve fibers.

We studied the contribution of peripheral opioid receptors to the morphine-induced antinociception in rats with a spinal nerve ligation-induced neuropathy. Intraplantar (i.pl.) injection of morphine produced a stronger suppression of nociceptive reflex responses of the neuropathic limb following ipsilateral, than contralateral, administration, whereas the morphine-induced effect on the control limb was independent of the injection side. Antinociception induced by systemically administered morphine was significantly attenuated by i.pl. injection of a peripherally acting opioid receptor antagonist in neuropathic but not in sham-operated rats. Following chemical sympathectomy with 6-hydroxydopamine, antinociception was achieved at a lower dose ipsilaterally, than contralaterally, following i.pl. administration of morphine, and the morphine-induced antinociception was attenuated by a peripherally acting opioid receptor antagonist. These results indicate that peripheral opioid receptors may contribute to the morphine-induced antinociception in the spinal nerve ligation-induced model of neuropathy. Sympathectomy of the neuropathic limb may underlie, at least partly, the increased peripheral efficacy of morphine in neuropathy.

Analgesics, Opioid↗

PubMed2001

Parathyroid hormone-related protein (PTHrP) induction in reactive astrocytes following brain injury: a possible mediator of CNS inflammation.

PTHrP, a peptide induced in parenchymal organs during endotoxemia and in the synovium in rheumatoid arthritis, has recently been shown to be expressed in immature or transformed human astrocytes, but not in normal cells. This finding has led us to postulate that PTHrP might also be induced in reactive astrocytes in inflamed brain and, thus, act as a mediator of CNS inflammation. To test this hypothesis, PTHrP expression was examined following cortical stab wound injury in rats, a classical model of reactive gliosis. To determine whether PTHrP was induced in glia by TNF-alpha, a known mediator of inflammation in brain and of PTHrP induction in peripheral tissues, and to determine whether PTHrP, in turn, mediated inflammatory changes in glia, in vitro studies with rat astrocytes and glial-enriched mixed brain cells were also undertaken. Consistent with previous reports of PTHrP expression in normal brain, neurons were the primary site of immunoreactive PTHrP expression in the injured cortex 1 day after stab wound injury. Over the subsequent 3 days, specific immunostaining for PTHrP and for GFAP, a marker of reactive astrocytes, appeared in reactive astrocytes at the wound edge and in perivascular astrocytes, reaching a maximum level of expression at the last time point examined (day 4). TNF-alpha induced PTHrP expression in astrocyte and glial-enriched brain cells in vitro, suggesting that this pro-inflammatory peptide was a possible mediator of PTHrP expression in CNS inflammation. PTHrP(1-34) acted in an additive fashion with TNF-alpha to induced astrocyte expression of IL-6, a cytokine with demonstrated neuroprotective effects. Astrocyte proliferation was inhibited by PTHrP(1-34) and PTHrP(1-141), acting via a PTH/PTHrP receptor cAMP signaling pathway. These studies suggest that PTHrP, analogous to its regulatory functions in other non-CNS models of inflammation, may be an important mediator of the inflammatory response in brain.

Animals↗

PubMed2001

[Effects of estrogen level on the function of vascular endothelial cells and expression of vascular cells adhesion molecule].

OBJECTIVE: To observe the effect of estrogen level on the secreting function of vascular endothelial cells of female rats, and to study the regulation of content of estrogen receptor in VECs and the expression of vascular cells adhesion molecule-1 by estrogen level. METHODS: Radioimmunity was adopted to measure the content of endothelin and PGI2 in serum of female rats, and copper-niger reduction was chosen to measure the content of nitric oxide in serum. Radioligand binding and flow cytometry were used to measure the expression of estrogen receptor and vascular cells adhesion molecule-1 in female rat lung VECs respectively. RESULTS: (1) The content of nitric oxide (18 mumol/L +/- 8 mumol/L) and PGI2(8.5 pg/ml +/- 2.5 pg/ml) in blood decreased after castration and increased remarkably(31 mumol/L +/- 7 mumol/L, P < 0.05; 10.9 pg/ml +/- 3.4 pg/ml) after estrogen was supplemented. However, the content of endothelin changed conversely(170 pg/ml +/- 39 pg/ml, 100 pg/ml +/- 32 pg/ml, P < 0.05). (2) The content of ER in female rat lung VECs (6.7 +/- 0.5 fmol/10(6) cell) decreased remarkably after castration and increased after estrogen was supplemented(17.6 +/- 1.2 fmol/10(6) cell, P < 0.01). (3) The expression rate of VCAM-1 in VECs increased significantly after interleukin-1 beta acted on the cells(17.5% +/- 1.5%). 17-beta estradiol at the contents of 3 x 10(-8)-10(-6) mol/L all counteracted the increase in expression rate of VCAM-1 induced by interleukin-1 beta (15.4% +/- 1.42%, 12.4% +/- 0.34%, 8.7% +/- 0.27%, P < 0.01). CONCLUSION: The estrogen level influences the secreting of NO, PGI2 and ET of VECs, and influences the content of ER in VECs. 17-beta estradiol at 3 x 10(-8)-10(-6) mol/L counteracts the increase of VCAM-1 in VECs induced by interleukin-1 beta.

Animals↗

PubMed2001

Arthropod bites manifesting as recurrent bullae in a patient with chronic lymphocytic leukemia.

BACKGROUND: We report a patient with chronic lymphocytic leukemia (CLL) that developed recurrent vesicobullous lesions that histologically demonstrated features of an exaggerated response to an arthropod bite. OBJECTIVE: Patients with CLL can present with many cutaneous manifestations, including specific and nonspecific lesions. Although rare, patients with CLL can develop an exaggerated response to an arthropod bite. CONCLUSION: Emphasis needs to be placed on the clinical recognition of arthropod bites as an unusual cutaneous manifestation of CLL, as they provide the physician with both a diagnostic and a therapeutic challenge. Patients often deny being bitten and, thus, the biopsy results conflict with the patient's history. Additionally, as there is no specific treatment, both the patient and physician are faced with a similar dilemma. Although our patient initially responded well to corticosteroids, his lesions significantly improved while being treated with dapsone.

Adrenal Cortex Hormones↗

PubMed2001

Modulation of pain by [1DMe]NPYF, a stable analogue of neuropeptide FF, in neuropathic rats.

The pain modulatory effects of (D-Tyr)L(Me-Phe)QPQRF-amide ([1DMe]NPYF), a stable analogue of neuropeptide FF were studied in rats with a chronic neuropathy induced by unilateral ligation of two spinal nerves. According to behavioral assessments, intrathecal (i.t.) administration of [1DMe]NPYF induced mechanical antiallodynic and thermal antinociceptive effects in a parallel and dose-dependent fashion, whereas following administration in the periaqueductal gray (PAG) it produced only mechanical antiallodynia. I.t. or PAG administration of FLFQPQRF, a non-amidated form of NPFF, or intraplantar injection of [1DMe]NPYF into the neuropathic paw had no effects. Electrophysiological results indicated that administration of [1DMe]NPYF suppressed responses of nociceptive spinal dorsal horn neurons in a submodality selective way and without an effect on their spontaneous activity; PAG administration predominantly suppressed brush-evoked responses and i.t. administration heat-evoked responses. The descending inhibitory effect by conditioning electrical stimulation of the PAG was enhanced by i.t. administration of [1DMe]NPYF. The reversibility of [1DMe]NPYF-induced effects by naloxone (1 mg/kg subcutaneously) depended on the submodality of test stimulation and the route of drug administration. The amplitude of the innocuous H-reflex was not changed by [1DMe]NPYF administered i.t. in control rats. The present results indicate that [1DMe]NPYF produces a selective attenuation of pain in neuropathic animals due to naloxone-sensitive or -insensitive central mechanisms depending on the submodality of pain and route of drug administration. The amide-group is essential for the [1DMe]NPYF-induced attenuation of pain.

Animals↗

PubMed2001

Genital lentigines in a 6-year-old boy with a family history of Cowden's disease: clinical and genetic evidence of the linkage between Bannayan-Riley-Ruvacalba syndrome and Cowden's disease.

BACKGROUND: In 1997, it was reported that a PTEN gene deletion, a common genetic mutation in Cowden's disease (CD), was identified in a patient with Bannayan-Riley-Ruvacalba (BRR), suggesting that the two diseases were allelic. However, the clinical overlap between the two diseases has largely remained unclear. OBJECTIVE: To confirm the genetic and clinical association in a family segregating both CD and BRR. METHODS: Clinical evaluation and genetic analysis using a denaturing gradient gel electrophoresis (DGGE), temporal temperature gradient electrophoresis (TTGE), and DNA sequencing techniques. RESULTS: Our patient presents with typical BRR clinical manifestations, including multiple lentigines on his penis, while his mother presents with typical manifestations of CD, including multiple malignancies. Genetic analyses of leukocytes from the patient and his mother showed mutations in exon 8 that was identified as the presumably truncating mutation R335X. CONCLUSION: This report provides clinical evidence that both BRR and CD are closely related and confirms the PTEN gene mutation in BRR and CD patients segregating in the same family, thus confirming the genetic linkage between the two genodermatoses.

Abnormalities, Multiple↗

PubMed2001

Childhood narcolepsy in North China.

STUDY OBJECTIVES: The purpose is to report the results of an effort to diagnose children with narcolepsy in a pediatric referral clinic. DESIGN: Between September 1998 and December 1999, a program was implemented to emphasize recognition of childhood narcolepsy. Patients underwent brain computed tomography (CT) scan and magnetic resonance imaging (MRI) testing. All children received a MSLT test following a routine night's sleep, and serological HLA typing for HLA DR2. Three who reported occasional snoring also underwent nocturnal PSG prior to the MSLT. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: 29 (21 male, 8 female) children were identified with sleepiness and cataplexy. There was no evidence for brain functional or structural disease or for drug use. Sleep paralysis was elicited in 41%; hypnagogic hallucinations, in 59%. Psychosocial problems including emotional irritability and social isolation were present in 93% of the patients. Mean sleep latency on MSLT was 2.0+/-1.3 minutes; sleep-onset rapid eye movement (SOREM) occurred during 2/5 naps in 28 of 29 patients and 3/5 in 26/29 patients. The average number and latency of SOREM episodes were 4.2+/-0.9 episodes and 4.0+/-1.7 minutes, respectively. In those with snoring, a nocturnal PSG did not disclose sleep apneas/hypopneas. All patients but one were HLA DR2 positive. The estimated clinic incidence was 0.04%. CONCLUSIONS: A program for recognition in a referral neurology clinic combined with an availability of the MSLT and HLA testing resulted in the new identification in North China of a number of children with narcolepsy syndromes.

Adolescent↗

PubMed2001

Characterization and tissue expression of a novel human gene npdc1.

We report the molecular characterization of a novel human homologue of mouse npdc1 (neural proliferation, differentiation and control, 1) gene, designated human npdc1 (hnpdc1). hnpdc1 was identified by large-scale sequencing of fetal liver cDNA libraries and the full-length cDNA was obtained by PCR amplification. The hnpdc1 gene, which contains nine exons, was mapped to human chromosome 15. It encodes a polypeptide of 325 amino acids, which shows high homology (77% identity) to the mouse NPDC1. Sequence analysis has shown that hNPDC1 protein contains a putative signal peptide of 34 amino acids, a transmembrane segment, and a typical bipartite nuclear localization signal. Northern blot and dot blot hybridization indicates that, just like mnpdc1, hnpdc1 mRNA is strongly expressed in adult brain (especially in hippocampus, frontal lobe and temporal lobe) and about 1.82-fold higher in adult brain than that in fetal brain. Unlike mnpdc1, however, hnpdc1 contains two transcripts instead of only one (1.5 kb), and has high expression levels in prostate, pituitary gland, and mammary glands. These results support that hNPDC1 plays a role in the control of neural cell proliferation and differentiation, and suggest that it may be involved in the development of several secretion glands.

Amino Acid Sequence↗

PubMed2001

Carboxymethylation of the PP2A catalytic subunit in Saccharomyces cerevisiae is required for efficient interaction with the B-type subunits Cdc55p and Rts1p.

Protein phosphatase 2A (PP2A) is an essential eukaryotic serine/threonine phosphatase known to play important roles in cell cycle regulation. Association of different B-type targeting subunits with the heterodimeric core (A/C) enzyme is known to be an important mechanism of regulating PP2A activity, substrate specificity, and localization. However, how the binding of these targeting subunits to the A/C heterodimer might be regulated is unknown. We have used the budding yeast Saccharomyces cerevisiae as a model system to investigate the hypothesis that covalent modification of the C subunit (Pph21p/Pph22p) carboxyl terminus modulates PP2A complex formation. Two approaches were taken. First, S. cerevisiae cells were generated whose survival depended on the expression of different carboxyl-terminal Pph21p mutants. Second, the major S. cerevisiae methyltransferase (Ppm1p) that catalyzes the methylation of the PP2A C subunit carboxyl-terminal leucine was identified, and cells deleted for this methyltransferase were utilized for our studies. Our results demonstrate that binding of the yeast B subunit, Cdc55p, to Pph21p was disrupted by either acidic substitution of potential carboxyl-terminal phosphorylation sites on Pph21p or by deletion of the gene for Ppm1p. Loss of Cdc55p association was accompanied in each case by a large reduction in binding of the yeast A subunit, Tpd3p, to Pph21p. Moreover, decreased Cdc55p and Tpd3p binding invariably resulted in nocodazole sensitivity, a known phenotype of CDC55 or TPD3 deletion. Furthermore, loss of methylation also greatly reduced the association of another yeast B-type subunit, Rts1p. Thus, methylation of Pph21p is important for formation of PP2A trimeric and dimeric complexes, and consequently, for PP2A function. Taken together, our results indicate that methylation and phosphorylation may be mechanisms by which the cell dynamically regulates PP2A complex formation and function.

Amino Acid Substitution↗

PubMed2001

Pain behavior and response properties of spinal dorsal horn neurons following experimental diabetic neuropathy in the rat: modulation by nitecapone, a COMT inhibitor with antioxidant properties.

We attempted to characterize a spinal neuronal correlate of painful neuropathy induced by diabetes mellitus (DM). Pain behavior and response properties of spinal dorsal horn neurons were determined in rats with a streptozocin-induced DM. A catechol-O-methyltransferase inhibitor with potent antioxidant properties, nitecapone, was used in an attempt to attenuate neuropathic symptoms. Behaviorally DM induced mechanical hypersensitivity that was markedly attenuated by oral treatment with nitecapone. The antihyperalgesic effect of nitecapone was not reversed by naloxone, an opioid antagonist, or atipamezole, an alpha-2-adrenoceptor antagonist. Electrophysiological recordings performed in pentobarbitone-anesthetized animals revealed that the most distinct abnormality in response properties of spinal dorsal horn wide-dynamic range (WDR) neurons was the increase in their spontaneous activity observed in untreated but not in nitecapone-treated DM rats. Conditioning electrical stimulation and a lidocaine block of the rostroventromedial medulla (RVM) had a similar modulatory effect on evoked responses of spinal dorsal horn WDR neurons in all experimental groups. The response properties of spinal dorsal horn nociceptive-specific or low-threshold mechanoreceptive neurons were not markedly different between the experimental groups. The results indicate that increased spontaneous activity in spinal dorsal horn WDR neurons may be causally related to behaviorally observed mechanical hypersensitivity in DM. Attenuation of the increased spontaneous activity in WDR neurons may explain the antihyperalgesic effect by nitecapone, due to naloxone- and alpha-2-adrenoceptor-insensitive mechanisms. DM or nitecapone treatment did not produce significant changes in phasic or tonic descending pain regulation originating in the RVM.

Adrenergic alpha-2 Receptor Antagonists↗

PubMed2001

Aspergillus nidulans alpha-1,3 glucanase (mutanase), mutA, is expressed during sexual development and mobilizes mutan.

We established a subtractive cDNA library of Aspergillus nidulans to identify differentially expressed genes during sexual development. One of the clones displayed homology to fungal alpha-1,3 glucanases (mutanase). Since alpha-1,3 glucan is considered the main reserve material accumulated during vegetative growth as a cell wall component and consumed during sexual development, we analyzed this gene in detail. The gene, mutA, is disrupted by three introns and encodes a putative protein of 48 kDa molecular mass with a signal peptide for secretion at the N terminus. The deduced protein displays amino acids 24-42% identical to mutanases of other fungi. A proposed mutan binding domain characterized in, e.g., Penicillium is not present in A. nidulans. Mutanase transcript and GFP reporter analysis in A. nidulans revealed specific induction of the gene during sexual development in Hülle cells. To study the role of mutA during sexual differentiation, we constructed a mutA deletion strain. Although degradation of mutan was affected in this strain, it was still able to form cleistothecia at a number similar to that of wildtype. These results suggest that additional carbon sources are available during sexual development.

Amino Acid Sequence↗

PubMed2001

A study of toxicity of 5-fluorouracil on bovine trabecular meshwork cells in vitro.

In order to explore whether the conventional use of 5-fluorouracil (5-Fu) had any toxic effects on trabecular meshwork cells, bovine trabecular meshwork cells were cultured in vitro and exposed to 5-Fu at different concentrations. The cellular morphology, ultrastructure, mortality and phagocytosis were studied under light microscopy, transmission electron microscopy and methods of Wright's stain. It was found that the toxic effects of 5-Fu on the cells were in a dose-dependent mode. 1 x 10(-1) mg/ml of 5-Fu caused a large part of cells rounded up, while 1 x 10(-2) mg/ml of the drug only a rough appearance of the cell surface. Exposure to 1 x 10(-2) mg/ml of 5-Fu made mitochrone swollen and rough endoplasmic reticulum enlarged, with the cell mortality being 50.5%. The latex microspheres engulfed in cytoplasm in cells receiving 1 x 10(-1) and 1 x 10(-2) mg/ml of 5-Fu were significantly decreased as compared with those in the control group (P < 0.01). It was concluded that the safe concentration of 5-Fu on bovine trabecular meshwork cells was 1 x 10(-2) mg/ml and the conventional dosage of 5-Fu in clinical practice would not cause injury to trabecular meshwork cells.

Animals↗

PubMed2001

Response properties of neurons in the rostroventromedial medulla of neuropathic rats: attempted modulation of responses by [1DMe]NPYF, a neuropeptide FF analogue.

We determined whether chronic neuropathy changes response properties of neurons in the rostroventromedial medulla of rats, and whether (d-Tyr)L(Me-Phe)QPQRF-amide, a neuropeptide FF analogue, in the periaqueductal gray produces changes in responses of rostroventromedial medullary neurons that might underlie its antiallodynic effect described earlier. Single unit recordings of medullary neurons were performed in lightly anesthetized neuropathic and control animals. Spontaneous activity and the responses to noxious thermal and mechanical stimulation of the hind paw were determined with and without administration of (d-Tyr)L(Me-Phe)QPQRF-amide. The neurons were classified into three groups: ON-neurons increased, OFF-neurons decreased, and NEUTRAL-neurons did not change their discharge rate prior to a limb withdrawal induced by noxious stimulation of the skin. Spontaneous activity and heat-evoked responses of ON-neurons were not different between neuropathic and control animals, whereas their mechanically evoked responses were reduced in neuropathy. Response properties of OFF-neurons were not different between neuropathic and control animals. Spontaneous activity of NEUTRAL-neurons was not different between neuropathic and control animals. (d-Tyr)L(Me-Phe)QPQRF-amide in the periaqueductal gray had no significant effect on evoked responses or spontaneous activity of ON- or OFF-neurons, independent of the experimental group. However, (d-Tyr)L(Me-Phe)QPQRF-amide produced a significant attenuation of spontaneous activity of NEUTRAL-neurons in neuropathic animals. In a behavioral study performed in unanesthetized animals it was found that intrathecal administration of methysergide, a serotonin antagonist, selectively attenuated neuropathic symptoms. Also, light pentobarbitone anesthesia markedly attenuated, but did not abolish, behaviorally determined neuropathic symptoms. From these results we suggest that NEUTRAL-neurons of the rostroventromedial medulla may have a role in neuropathy and they may be involved in attenuation of mechanical hypersensitivity by (d-Tyr)L(Me-Phe)QPQRF-amide in the periaqueductal gray. It is proposed that in neuropathy the synaptic effects of descending impulses from medullary NEUTRAL-neurons on their axonal targets in the spinal cord are changed so that this contributes to mechanical hypersensitivity, due to mechanisms that are at least partly serotoninergic.

Action Potentials↗

PubMed2001

Lithium suppresses excitotoxicity-induced striatal lesions in a rat model of Huntington's disease.

Huntington's disease is a progressive, inherited neurodegenerative disorder characterized by the loss of subsets of neurons primarily in the striatum. In this study, we assessed the neuroprotective effect of lithium against striatal lesion formation in a rat model of Huntington's disease in which quinolinic acid was unilaterally infused into the striatum. For this purpose, we used a dopamine receptor autoradiography and glutamic acid decarboxylase mRNA in situ hybridization analysis, methods previously shown to be adequate for quantitative analysis of the excitotoxin-induced striatal lesion size. Here we demonstrated that subcutaneous injections of LiCl for 16 days prior to quinolinic acid infusion considerably reduced the size of quinolinic acid-induced striatal lesion. Furthermore, these lithium pre-treatments also decreased the number of striatal neurons labeled with the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Immunohistochemistry and western blotting demonstrated that lithium-elicited neuroprotection was associated with an increase in Bcl-2 protein levels. Our results raise the possibility that lithium may be considered as a neuroprotective agent in treatment of neurodegenerative diseases such as Huntington's disease.

Animals↗

PubMed2001

An attempt at intracytoplasmic sperm injection of frozen-thawed minke whale (Balaenoptera bonaerensis) oocytes.

Little is known about the characteristics of fertilisation events in minke whales. Cryopreserved minke whale oocytes and spermatozoa do not fertilise in a standard IVF. This study was conducted to investigate the pronucleus formation ability of cryopreserved minke whale oocytes and their subsequent development following intracytoplasmic sperm injection (ICSI). In experiment 1, frozen-thawed minke whale immature oocytes were cultured for in vitro maturation (IVM) in a maturation medium (TCM199) supplemented with either porcine follicle stimulating hormone (pFSH)/estradiol-17beta (E2) or pregnant mare's serum gonadotropin (PMSG)/human chorionic gonadotropin (hCG). After 120 h of IVM, oocyte survival was examined before ICSI, and showed no significant difference in morphological normality (24-36%) between the two IVM media. Two-cell embryos (two oocytes from 21 sperm-injected oocytes) were obtained when the maturation medium was supplemented with pFSH/E2 or PMSG/hCG. In experiment 2, cryopreserved maturing oocytes were investigated for the effects of repeat-culture (2 h or 24 h) on survival before ICSI. Pronuclear formation and development were examined for the effects of sperm pretreatment with dithiothreitol (DTT) and oocyte activation with ethanol at ICSI. A frequency of 49-69% of frozen-thawed maturing oocytes was used for ICSI. Although oocyte activation did not produce a significant difference in survival, pronucleus formation and embryonic development, 2- and 4-cell cleaved oocytes were observed after injection of sperm pretreated with DTT.

Animals↗

PubMed2001

Melatonin and its analogs potentiate the nifedipine-sensitive high-voltage-activated calcium current in the chick embryonic heart cells.

Effects of melatonin and its analogs on the voltage-activated calcium current of embryonic chick ventricular cardiomyocytes were investigated. Myocytes were dissociated from 14- to 16-day-old chicks (yellow Red Rob) embryonic hearts and cultured for 2 3 days. Calcium currents were studied by the patch-clamp technique. Whole-cell current recording showed nifedipine-sensitive, high-voltage-activated L-type calcium current inactivated in 70-100 ms during the voltage step period of 200 ms. There was no evidence of low-voltage-activated T-type calcium channels. Melatonin (ejected solution: 50 micromol/L melatonin; concentration at the vicinity of recording cell: about 1-5 micromol/L melatonin) and its analogs, 2-iodomelatonin and 2-iodo-n-butanol-5-methoxytryptamine, significantly increased the amplitude of the calcium current by 42-62%. The effect of melatonin on the L-type calcium current was not desensitised by repeated melatonin treatment. Our results suggest a specific melatonin receptor-mediated action on the calcium channel of the embryonic chick myocyte. The melatonin-induced increase in high-voltage calcium current may increase myocyte contractility and enhance cardiac output. A regulatory role of melatonin on the chick cardiac function should be further considered.

Animals↗

PubMed2001

The penetration of 0.005% fluticasone propionate ointment in eyelid skin.

BACKGROUND: The use of corticosteroids to treat periorbital dermatoses carries significant risk of serious side effects such as glaucoma, cataracts, and blindness. Studies to assess levels of corticosteroid penetration in the eyelid are lacking. OBJECTIVE: We assessed corticosteroid penetration in eyelid skin in vitro to obtain information leading to the establishment of safer dosing regimens. METHODS: Fluticasone propionate ointment, 0.005%, was applied (approximately 2-5 mg/cm(2)) to samples of human eyelid skin, and penetration was assessed by using modified Franz diffusion cells. Drug concentration was determined at 12, 24, 36, and 48 hours after application by liquid chromatography tandem mass spectrometry. RESULTS: Only very small amounts of fluticasone propionate penetrated the skin (range, 0.618% +/- 0.339% to 1.467% +/- 0.695%). CONCLUSION: Further studies are warranted to examine the safety and efficacy of 0.005% fluticasone propionate ointment for the treatment of eyelid dermatoses.

Administration, Topical↗