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Biomedical subjects

Yumiko Abe

Publications and source records attributed to Yumiko Abe.

17 recordsLinked to original sources
PubMed2006

Identification of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible genes in human amniotic epithelial cells.

BACKGROUND: Exposure to dioxins results in a broad range of pathophysiological disorders in human fetuses. In order to evaluate the effects of dioxins on the feto-placental tissues, we analyzed the gene expression in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) treated primary cultures of human amniotic epithelial cells. METHODS: Human amniotic epithelial cells were dispersed by trypsin from amniotic membranes and cultured in DME/Ham's F12 medium supplemented with 10% FBS. Two weeks after plating, cells were treated with 50 nM TCDD or DMSO (control), further incubated for 48 hrs, and the gene expression was analyzed by DNA microarray technology and quantitative real-time PCR. RESULTS: Thirty eight TCDD-inducible genes, including cytochromeP4501A1 and cytochromeP4501B1, were identified. One of the remarkable profiles of the gene expression was the prominent up-regulation of interferon-inducible genes. The genes involved in the interferon gene expression and interferon signaling pathways were also up-regulated. Furthermore, the expression of genes related to collagen synthesis or degradation was enhanced by TCDD. CONCLUSION: Using DNA microarray and quantitative real-time PCR analyses, we identified TCDD-inducible genes, including interferon-inducible genes and genes related to collagen synthesis or degradation, in human amniotic epithelial cells.

Amnion↗
PubMed2006

Does the Rayleigh equation apply to evaluate field isotope data in contaminant hydrogeology?

Stable isotope data have been increasingly used to assess in situ biodegradation of organic contaminants in groundwater. The data are usually evaluated using the Rayleigh equation to evaluate whether isotope data follow a Rayleigh trend, to calculate the extent of contaminant biodegradation, or to estimate first-order rate constants. However, the Rayleigh equation was developed for homogeneous systems while in the subsurface, contaminants can migrate at different velocities due to physical heterogeneity. This paper presents a method to quantify the systematic effect that is introduced by applying the Rayleigh equation to field isotope data. For this purpose, the travel time distribution between source and sampling point is characterized by an analytical solution to the advection-dispersion equation. The systematic effect was evaluated as a function of the magnitude of physical heterogeneity, geometry of the contaminant plume, and degree of biodegradation. Results revealed that the systematic effect always leads to an underestimation of the actual values of isotope enrichment factors, the extent of biodegradation, or first-order rate constants, especially in the dispersion-dominant region representing a higher degree of physical heterogeneity. A substantial systematic effect occurs especially for the quantification of first-order rate constants (up to 50% underestimation of actual rate) while it is relatively small for quantification of the extent of biodegradation (< 5% underestimation of actual degree of biodegradation). The magnitude of the systematic effect is in the same range as the uncertainty due to uncertainty of the analytical data, of the isotope enrichment factor, and the average travel time.

Biodegradation, Environmental↗
PubMed2005

Spinal stenosis due to ossified lumbar lesions.

OBJECT: Spinal stenosis due to lumbar ossified lesions is a rare pathological entity. The authors retrospectively evaluated the clinical features and surgical results associated with cases involving lumbar ossified lesion-induced stenosis. METHODS: Data obtained in 20 surgically treated patients with lumbar hyperostotic spinal stenosis were included. To evaluate the background of the disease, body mass index and general complications were assessed. Whole-spine radiological examination was conducted. The presence of ossification of the posterior longitudinal ligament or ossification of the ligamentum flavum was evaluated. Surgical results were classified according to the Japanese Orthopaedic Association (JOA) scale. In the patients in whom neurological deterioration was observed during follow up, the causes of deterioration were reviewed. Seven patients (35%) were obese and six patients (30%) suffered diabetes mellitus. Twelve patients harbored coexisting cervical and/or thoracic ossified lesions. The overall mean JOA score improved from 10.2 to a peak of 22.5; at last follow-up examination the mean JOA score was 20.9. In female and older patients with a long history of preoperative symptoms, a low preoperative JOA score, and other spinal lesions, recovery tended to be poorer. Recovery was poor in one patient, and neurological deterioration due to coexisting ossified spinal lesions occurred in another patient during the follow-up period. CONCLUSIONS: Because coexisting ossified lesions were frequently seen, whole-spine analysis is recommended. Early diagnosis and appropriate treatment are important to achieve a better surgical outcome.

Adult↗
PubMed2004

The role of Fas-mediated apoptosis after traumatic spinal cord injury.

STUDY DESIGN: Functional recovery and histopathological change after spinal cord injury in the Fas-deficient mice and the wild-type mice were investigated. OBJECTIVES: To investigate the role of the Fas/Fas ligand (FasL) system as a signal transduction pathway leading to apoptosis after spinal cord injury. SUMMARY OF BACKGROUND DATA: [corrected] Apoptosis observed after spinal cord injury has recently gained widespread interest as a cause of collateral damage after the initial injury. Apoptosis mediated by the Fas antigen in the postischemic brain or spinal cord was reported. Recently, the upregulation of Fas after spinal cord injury was also reported. However, the influence of Fas-mediated apoptosis on the extent of the secondary spinal cord injury has not yet been clarified. METHODS: We investigated Fas-mediated apoptosis after spinal cord injury and examined the behavioral changes and the histopathological changes after spinal cord injury using MRL/Mp-lpr/lpr (MRL/lpr) mice, which were Fas-deficient mutant mice, and MRL/Mp-+/+ (MRL/+) mice, which were Fas-positive wild-type mice. RESULTS: Locomotor recovery after spinal cord injury in MRL/lpr mice was superior to that observed in MRL/+ mice. In addition, the damaged area in MRL/lpr mice was significantly smaller than that seen in MRL/+ mice. Further, the frequency of apoptotic cells in the injured spinal cord of MRL/lpr mice was significantly less than that in MRL/+ mice. CONCLUSION: We demonstrated the appearance of Fas-mediated apoptosis in the spinal cord after spinal cord injury. In addition, we elucidated for the first time that Fas-mediated apoptosis following spinal cord injury played an important role in the spinal cord damage and the ultimate neurologic injury.

Animals↗
PubMed2004

Calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1) is a pharmacological target of differentiation-inducing factor-1, an antitumor agent isolated from Dictyostelium.

The differentiation-inducing factor-1 (DIF-1) isolated from Dictyostelium discoideum is a potent antiproliferative agent that induces growth arrest and differentiation in mammalian cells in vitro. However, the specific target molecule(s) of DIF-1 has not been identified. In this study, we have tried to identify the target molecule(s) of DIF-1 in mammalian cells, examining the effects of DIF-1 and its analogs on the activity of some candidate enzymes. DIF-1 at 10-40 micro M dose-dependently suppressed cell growth and increased the intracellular cyclic AMP concentration in K562 leukemia cells. It was then found that DIF-1 at 0.5-20 micro M inhibited the calmodulin (CaM)-dependent cyclic nucleotide phosphodiesterase (PDE1) in vitro in a dose-dependent manner. Kinetic analysis revealed that DIF-1 acted as a competitive inhibitor of PDE1 versus the substrate cyclic AMP. Because DIF-1 did not significantly affect the activity of other PDEs or CaM-dependent enzymes and, in addition, an isomer of DIF-1 was a less potent inhibitor, we have concluded that PDE1 is a pharmacological and specific target of DIF-1.

Binding, Competitive↗
PubMed2004

Activin receptor signaling.

Activin is a member of the TGF-beta superfamily and has various effects on diverse biological systems. Activins initiate their cellular responses by binding to their receptors with intrinsic serine/threonine kinase activity and activation of specific downstream intracellular effectors termed Smad proteins. Smads relay the signal from the cell membrane to the nucleus, where they affect the transcription of target genes. Negative regulation of activin signal occurs at the extracellular, membrane, cytoplasmic and nuclear levels. The presence of many mechanisms for regulation shows its importance to normal physiology. Here, we review the latest advances in activin signal transduction.

Activin Receptors↗
PubMed2003

Pathomechanism of myelopathy and surgical results of laminoplasty in elderly patients with cervical spondylosis.

STUDY DESIGN: Clinical and radiologic analyses in elderly patients with cervical myelopathy. OBJECTIVE: To investigate the pathomechanism of cervical myelopathy and the surgical results of laminoplasty in elderly patients older than 70 years old. SUMMARY OF BACKGROUND DATA: To date, there have been no reports on the pathomechanism of cervical myelopathy in elderly patients. Further, the surgical results and postoperative complications of laminoplasty have not been fully evaluated in elderly patients. METHODS: Eighty-nine patients who underwent cervical laminoplasty were reviewed. The patients were divided into 2 groups according to the age at the time of operation (the elderly patient group: 20 patients who were older than 70 years old, and the control group: 69 patients who were younger than 69 years old). Pre- and postoperative neurologic status (the Japanese Orthopedic Association score) and postoperative complications were compared between the two groups. Radiologic features were also examined. RESULTS: There was no statistical difference in the recovery rate of Japanese Orthopedic Association score between the elderly patient group and the control group. Activities of daily living improved in the elderly patients. Several complications, such as delirium and worsening hypertension, were found in the elderly patient group. In the preoperative radiographs, the incidence of either retrolisthesis or anterolisthesis in the elderly patient group was significantly higher than that in the control group. CONCLUSIONS: Retrolisthesis and anterolisthesis are often the cause of myelopathy in elderly patients. Surgical decompression for cervical myelopathy was beneficial even in elderly patients older than 70 years old. Laminoplasty achieves stability of the cervical spine, and this procedure is reasonable for the treatment.

Aged↗
PubMed2003

Zinc inhibits calcineurin activity in vitro by competing with nickel.

Calcineurin (CN) is a Ca(2+)/calmodulin (CaM)-dependent protein serine/threonine phosphatase that contains Zn(2+) in its catalytic domain and can be stimulated by divalent ions such as Mn(2+) and Ni(2+). In this study, the role of exogenous Zn(2+) in the regulation of CN activity and its relevance to the role of Ni(2+) was investigated. Zn(2+) at a concentration range of 10nM-10 micro M inhibited Ni(2+)-stimulated CN-activity in vitro in a dose-dependent manner and approximately 50% inhibition was attained with 0.25 micro M Zn(2+). Kinetic analysis showed that Zn(2+) inhibited the activity of CN by competing with Ni(2+). Interaction of CN and CaM was not inhibited with Zn(2+) at 10 micro M. Zn(2+) never affected the activity of cAMP phosphodiesterase 1 or myosin light-chain kinase (CaM-dependent enzymes) and rather activated alkaline phosphatase. The present results indicate that Zn(2+) should be a potent inhibitor for CN activity although this ion is essential for CN.

Alkaline Phosphatase↗
PubMed2003

Biological effects of glycolic acid on dermal matrix metabolism mediated by dermal fibroblasts and epidermal keratinocytes.

Glycolic acid (GA), one of the alpha-hydroxy acids, is widely used as an agent for chemical peeling. Although there are several reports about the clinical effects of GA in the literature, its biological mechanism remains mostly unclear, and there are only a few reports about its effects on skin rejuvenation mediated by keratinocytes. The aim of this study was to investigate the effect of GA on the dermal matrix metabolism of keratinocytes and fibroblasts using in vitro and ex vivo systems. Our study shows that GA not only directly accelerates collagen synthesis by fibroblasts, but it also modulates matrix degradation and collagen synthesis through keratinocyte-released cytokines. We confirm that IL-1alpha is one of the primary mediators for matrix degradation released from keratinocytes after GA treatment. These results suggest that GA contributes to the recovery of photodamaged skin through various actions, depending on the skin cell type.

Dermis↗
PubMed2003

Decreased neural damage after spinal cord injury in tPA-deficient mice.

Tissue plasminogen activator (tPA) is a serine protease that converts plasminogen to plasmin. It plays an important role in the nervous system, including the processes of neuronal migration, neurite outgrowth, and neuronal plasticity. tPA has also been suggested to have a role in several neuropathological conditions, such as cerebral ischemia, seizures, and demyelinating diseases. To investigate the role of tPA in spinal cord injury, wild-type mice and mice with homozygous tPA deficiency (tPA(-/-) mice) were subjected to spinal cord contusion and the differences of hindlimb function, electrophysiological changes, and histopathological changes were assessed for 6 weeks. Functional recovery was greater in tPA(-/-) mice than in wild-type mice throughout the observation period. The time course of myoelectric motor-evoked potentials supported the hindlimb functional findings. Histological examination showed that injured areas were smaller in tPA(-/-) mice than wild-type mice on Luxol fast blue staining or myelin basic protein and neurofilament protein immunostaining at 6 weeks after contusion. Electron microscopy showed that the white matter was better preserved in tPA(-/-) mice than in wild-type mice. The expression of tPA protein was widespread on the first day after contusion and this expression was detected for at least a week. Activation of microglia/macrophages and apoptotic cell death were significantly reduced in tPA(-/-) mice after contusion. This study shows that neural damage is decreased in tPA(-/-) mice after spinal cord injury. Suppression of tPA production may help to decrease secondary injury after spinal cord contusion.

Animals↗
PubMed2002

Ovarian follicular differentiation with prepubertal gonadotropin surges and gonadotropin priming in mice.

Preantral follicles were mechanically isolated from the ovaries of 1.5 to 8 week old mice and cultured in vitro for 4 days in the presence or absence of either activin A or FSH. Plasma gonadotropin, estradiol and immunoreactive (IR) inhibin levels were measured. Cultured follicles showed stepwise changes in response to recombinant human (rh) FSH, with no response until 11 days, a gradual increase from 2 weeks, culminating in a strong response to rhFSH at 8 weeks. The response to activin A was vice versa. It enhanced the effect of rhFSH on preantral follicular growth of up to 4-week-old mice, but inhibited the effect of rhFSH in 8-week-old mice. The peak of the prepubertal gonadotropin surge was observed on day 11. Seven-day-old mice were treated with either luteinizing hormone releasing hormone (LHRH) or rhFSH or human chorionic gonadotropin (hCG) for 3 consecutive days from day 7, and follicles were collected on day 11. Those follicles showed enhanced response to rhFSH, no response to activin A, and an enhanced response to the combination of rhFSH and activin A, suggesting that the chronological changes in follicular response are a result of the prepubertal gonadotropin surge.

Aging↗
PubMed2002

T1-2 disc herniation following an en bloc cervical laminoplasty.

We report a rare case of T1-2 disc herniation following cervical laminoplasty. A 56-year-old male patient presented with left foot-drop and gait disturbance of abrupt onset 11 years after a successful laminoplasty from C3-7. Magnetic resonance imaging revealed spinal stenosis at T1-2 due to intervertebral disc herniation and ligamentum flavum hypertrophy. Three days later, laminectomy with disc fragment excision was performed at that level. Two weeks after surgery, he was able to walk without assistance. Mechanical stresses may have directly affected the T1-2 intervertebral disc following laminoplasty and may have caused disc herniation.

Cervical Vertebrae↗
PubMed2002

Is leptin a key factor which develops obesity by ovariectomy?

Withdrawal of estrogen by ovariectomy increases adiposity, but decreases the circulating levels of the ob gene product, leptin, which inhibits food intake. The reduction of circulating leptin levels may thus play an important role in the induction of obesity by ovariectomy. To examine this hypothesis, body weight change by ovariectomy was investigated in leptin-deficient genetically obese (ob/ob) mice with leptin supplement. Prior to the operation, obese (ob/ob) female mice were treated with intraperitoneal administration of recombinant mouse leptin (1.0 microg/g body weight/day) for 8 days. Then, half of the leptin-treated mice and their lean littermates were bilaterally ovariectomized and their body weight changes were observed for 56 days. From 16 days after the operation, a significant increase in body weight by ovariectomy was observed only in lean mice without leptin treatment. From 44 days, a significant body weight gain by ovariectomy was observed in leptin-treated obese mice. Ovariectomy significantly increased retroperitoneal white adipose tissue weight in their lean littermates, but not in leptin-treated obese mice. It was suggested that the reduction of circulating leptin levels may play an important role in the increases of acute phase body weight gain by ovariectomy, but during static phase, the direct effects of estrogen withdrawal may appear independent of leptin-mediated effects.

Adipose Tissue↗
PubMed2002

Ovarian function in three female patients with McCune-Albright syndrome with persistent autonomous ovarian activity.

Autonomous ovarian activity persists throughout adolescence in some patients with McCune-Albright syndrome (MAS). There have been few studies of longitudinal assessment of ovarian function in these patients. We investigated the first morning voided urinary gonadotropin and ovarian steroid levels consecutively in three patients aged 3 to 7 years after withdrawal of therapy for precocious puberty. They had the triad of MAS with onset of menses within the first 3 years of life. Excessively elevated urinary estrogen levels with one or two peaks per cycle were found in all patients. In two patients, café-au-lait spots and dysplastic bones were located unilaterally. These two patients showed significantly increased urinary pregnanediol levels, suggesting ovulation, with low levels of gonadotropins in one patient and moderately low levels with an LH surge in the other. Thus, only a unilateral ovary was anticipated to be mutated with persistent autonomous ovarian activity. In the remaining patient with bilateral involvement of tissues, relatively high LH and low FSH levels throughout a cycle were found with no rise in urinary pregnanediol.

Adolescent↗
PubMedDate not supplied

Postoperative delirium in spine surgery.

BACKGROUND CONTEXT: Postoperative delirium is a great concern in the treatment of hip fracture. However, there have been no reports regarding the postoperative delirium in spine surgery. PURPOSE: To determine the incidence and risk factors for postoperative delirium in the patients who have had spine surgery. STUDY DESIGN/SETTING: The incidence and intraoperative risk factors of postoperative delirium were retrospectively examined in patients who had spine surgery during a 3-year period. PATIENT SAMPLE: Three hundred forty-one patients who underwent spine surgery from 2000 to 2002 were included. METHODS: The presence of delirium was determened by the Confusion Assessment Method. Laboratory data were checked preoperatively, at 1 day and 1 week postoperatively. The prognosis of postoperative delirium was evaluated. RESULTS: Postoperative delirium was found in 13 patients; all of them were in their 70's or 80's. The incidence of delirium was 12.5% in the patients over 70 years old. Hemoglobin and hematocrit levels at 1 day after surgery in the delirium group were significantly lower than those in the control group. One patient had persistent cognitive dysfunction after surgery. Two patients who developed postoperative delirium died during the follow-up period. CONCLUSION: Low concentrations of hemoglobin and hematocrit 1 day after surgery were risk factors for postoperative delirium. As delirium is thought to represent not only brain dysfunction, but also impaired general physical condition, careful observation is necessary for the management of patients with postoperative delirium.

Adolescent↗