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Biomedical subjects

F Kawasaki

Publications and source records attributed to F Kawasaki.

16 recordsLinked to original sources
PubMed2001

The production and clinical evaluation of macrophage colony-stimulating factor and macrophage chemoattractant protein-1 in human follicular fluids.

PROBLEM: In order to investigate the role of macrophage colony-stimulating factor (M-CSF) and macrophage chemoattractant protein-1 (MCP-1) in human ovulation, we measured the concentrations of M-CSF and MCP-1 in human follicular fluids (FFs) and correlated them with oocyte maturation. METHOD OF STUDY: The oocytes were obtained from the FFs of 46 women undergoing in vitro fertilization and embryo transfer (IVF ET). The concentrations of M-CSF and MCP-1 in the FFs were measured by enzyme-linked immunosorbent assay. In addition, granulosa cells obtained from the FFs of IVF patients were cultured and treated with forskolin and 12-O-tetradecanoylphorbol 13-acetate (TPA) for 24 48 hr. RESULTS: Concentrations of M-CSF and MCP-1 were significantly higher in the FFs than in the serum (P < 0.01). M-CSF concentrations tended to be higher, while MCP-1 concentrations were significantly higher in the FFs containing mature oocytes than in FFs containing immature oocytes (P < 0.05). The production of M-CSF was markedly increased over the basal level after treatment with forskolin (10 microM) for 24 (P < 0.02) and 48 hr (P < 0.01); however, the production of MCP-1 was unchanged. CONCLUSIONS: Our data suggest that M-CSF and MCP-1 may play an important role in human preovulatory processes and that M-CSF, in particular, may be regulated by cyclic adenosine monophosphate. M-CSF and MCP-1 may also be valuable biochemical markers in the evaluation of oocyte maturation.

Adult↗
PubMed2000

A temperature-sensitive paralytic mutant defines a primary synaptic calcium channel in Drosophila.

Neurotransmission at chemical synapses involves regulated exocytosis of neurotransmitter from the presynaptic terminal. Neurotransmitter release is thought to be triggered by calcium influx through specific classes of voltage-gated calcium channels. Here we report genetic and functional analysis implicating a specific calcium channel gene product in neurotransmitter release. We have isolated a temperature-sensitive paralytic allele of the Drosophila calcium channel alpha1 subunit gene, cacophony (cac). This mutant, referred to as cac(TS2), allows functional analysis of synaptic transmission after acute perturbation of a specific alpha1 subunit. Electrophysiological analysis at neuromuscular synapses revealed that neurotransmitter release in cac(TS2) is markedly reduced at elevated temperatures, indicating that cac encodes a primary alpha1 subunit functioning in synaptic transmission. These observations further define the molecular basis of voltage-gated calcium entry at synapses and provide a new starting point for further genetic analysis of synaptic mechanisms.

Animals↗
PubMed2000

Fast synaptic fatigue in shibire mutants reveals a rapid requirement for dynamin in synaptic vesicle membrane trafficking.

The GTPase dynamin is involved in endocytosis in many cell types, as first revealed by temperature-sensitive paralytic mutations in the Drosophila dynamin gene, shibire (shi), which disrupt synaptic vesicle endocytosis and deplete synaptic terminals of vesicles. Here we report that shi synapses exhibit a fast synaptic fatigue phenotype within 20 ms of repetitive stimulation, which cannot be explained by vesicle depletion, as we confirmed by electron microscopy. These results suggest that, in addition to its well-characterized role in synaptic vesicle recycling, dynamin may be required for short-term maintenance of the readily releasable pool of synaptic vesicles.

Animals↗
PubMed1999

The Drosophila NSF protein, dNSF1, plays a similar role at neuromuscular and some central synapses.

The N-ethylmaleimide sensitive fusion protein (NSF) was originally identified as a cytosolic factor required for constitutive vesicular transport and later implicated in synaptic vesicle trafficking as well. Our previous work at neuromuscular synapses in the temperature-sensitive NSF mutant, comatose (comt), has shown that the comt gene product, dNSF1, functions after synaptic vesicle docking in the priming of vesicles for fast calcium-triggered fusion. Here we investigate whether dNSF1 performs a similar function at central synapses associated with the well-characterized giant fiber neural pathway. These include a synapse within the giant fiber pathway, made by the peripherally synapsing interneuron (PSI), as well as synapses providing input to the giant fiber pathway. The latency (delay) between stimulation and a resulting muscle action potential was used to assess the function of each class of synapses. Repetitive stimulation of the giant fiber pathway in comt produced wild-type responses at both 20 and 36 degrees C, exhibiting a characteristic and constant latency between stimulation and the muscle response. In contrast, stimulation of presynaptic inputs to the giant fiber (referred to as the "long latency pathway") revealed a striking difference between wild type and comt at 36 degrees C. Repetitive stimulation of the long latency pathway led to a progressive, activity-dependent increase in the response latency in comt, but not in wild type. Thus the giant fiber pathway, including the PSI synapse, appears to function normally in comt, whereas the presynaptic inputs to the giant fiber pathway are disrupted. Several aspects of the progressive latency increase observed in the long latency pathway can be understood in the context of the activity-dependent reduction in neurotransmitter release we observed previously at neuromuscular synapses. These results suggest that repetitive stimulation causes a progressive reduction in neurotransmitter release by presynaptic inputs to the giant fiber neuron, resulting in an increased latency preceding a giant fiber action potential. Thus synapses presynaptic to the giant fiber appear to utilize dNSF1 in a manner similar to the neuromuscular synapse, whereas the PSI chemical synapse may differ with respect to the expression or activity of dNSF1.

Animals↗
PubMed1999

Torsion of a functional ovarian cyst in a premenopausal patient receiving tamoxifen.

We report a case of torsion of an ovarian follicular cyst that developed during treatment with tamoxifen for breast cancer. A 40-year-old Japanese woman was admitted complaining of acute lower abdominal pain. Eight months earlier, she had undergone a partial mastectomy and local irradiation for ductal carcinoma of her left breast, estrogen receptor-positive stage I (T(1a) N(1b) M(0)). The administration of tamoxifen, 20 mg/day, and doxifluridine, 600 mg/day, were started immediately postoperatively. Pelvic examination after admission revealed the left ovarian cyst and enlarged uterus. Transvaginal ultrasonography and computed tomography revealed a multilocular cystic mass in the pelvic cavity. The pathological diagnosis of the tumor after total hysterectomy and bilateral salpingo-oophorectomy was a typical follicular cyst with torsion and uterine leiomyoma. This ovarian cyst was believed to have developed during tamoxifen administration.

Adult↗
PubMed1998

Synaptic physiology and ultrastructure in comatose mutants define an in vivo role for NSF in neurotransmitter release.

N-Ethylmaleimide-sensitive fusion protein (NSF) is a cytosolic protein thought to play a key role in vesicular transport in all eukaryotic cells. Although NSF was proposed to function in the trafficking of synaptic vesicles responsible for neurotransmitter release, only recently have in vivo experiments begun to reveal a specific function for NSF in this process. Our previous work showed that mutations in a Drosophila NSF gene, dNSF1, are responsible for the temperature-sensitive paralytic phenotype in comatose (comt) mutants. In this study, we perform electrophysiological and ultrastructural analyses in three different comt alleles to investigate the function of dNSF1 at native synapses in vivo. Electrophysiological analysis of postsynaptic potentials and currents at adult neuromuscular synapses revealed that in the absence of repetitive stimulation, comt synapses exhibit wild-type neurotransmitter release at restrictive (paralytic) temperatures. In contrast, repetitive stimulation at restrictive temperatures revealed a progressive, activity-dependent reduction in neurotransmitter release in comt but not in wild type. These results indicate that dNSF1 does not participate directly in the fusion of vesicles with the target membrane but rather functions in maintaining the pool of readily releasable vesicles competent for fast calcium-triggered fusion. To define dNSF1 function further, we used transmission electron microscopy to examine the distribution of vesicles within synaptic terminals, and observed a marked accumulation of docked vesicles at restrictive temperatures in comt. Together, the results reported here define a role for dNSF1 in the priming of docked synaptic vesicles for calcium-triggered fusion.

Animals↗
PubMed1995

Structure and innervation of longitudinal and transverse abdominal muscles of the cricket, Gryllus bimaculatus.

Detailed morphological and physiological studies on the insect abdominal muscles, including their innervation and neuromuscular transmission, are essential for understanding their important role in respiratory movements. There are both longitudinal and transverse muscles in the ventral abdominal segments of the cricket, Gryllus bimaculatus. Muscle 202 was selected as an example of a longitudinal muscle. This muscle is, on average, 1.4 mm long, paired on both sides of the abdomen, and consists of 127 fibers whose mean maximum diameter is 32 microns; the average sarcomere length is 8.1 microns. It is innervated by two ipsilateral motoneurons in the second abdominal ganglion, the axons of which run in the ipsilateral first nerve root of the third abdominal ganglion. Two motor axons run in parallel from the two cell bodies and innervate in close proximity. Accordingly, large and small excitatory junctional potentials (EJPs) are recorded from the same fiber with slightly different thresholds when the first nerve root of the third abdominal ganglion is stimulated. Muscle 203, which is a transverse muscle that extends across the fifth abdominal sternum and is located over the fourth abdominal ganglion and muscle 202 on both sides, is, on average, 2.9 mm long and consists of 86 fibers with a maximum diameter of 33 microns. The average sarcomere length is 7.9 microns. The right or left half of the muscle is innervated mainly by a contralateral motoneuron in the third abdominal ganglion through the ipsilateral first nerve root of the third abdominal ganglion. Nerve branches of the first nerve root also reach muscles 188 and 218. Muscle 203 is additionally innervated by the first nerve roots of abdominal ganglia 1, 2, and 4. These innervations were ascertained both electrophysiologically and histologically. Individual muscle fibers of muscle 203 produced small EJPs in response to stimulation of the first nerve roots of abdominal ganglia 2, 3, and 4 and large EJPs in response to stimulation of the root from the first abdominal ganglion. The large and small EJPs in muscle 203 have properties similar to those in muscle 202.

Abdominal Muscles↗
PubMed1993

Responses to Ca2+ of two types of excitatory junctional potentials in cricket muscles.

Cricket (Gryllus bimaculatus) abdominal muscle 202 produced both small and large excitatory junctional potentials (EJPs) depending on the intensity of the stimulation to the nerve. Abdominal muscle 203 generated only small EJPs. The large EJPs, the threshold of which was always slightly higher than the small EJPs, were more sensitive to the Ca2+ concentration at which they were evoked and to concentration changes. There were no marked differences between the two muscles regarding the electrical properties of the muscle fibre membrane and the quantal size of the transmitter. The causes of the differences between the two types of EJPs in these muscles are discussed.

Animals↗
PubMed1990

Spontaneous and evoked transmitter releases after concanavalin A treatment are affected differently by hypertonic low calcium solutions at frog neuromuscular junction.

Adding sucrose to the low calcium bathing solution made with no added calcium but containing Mg2+ EGTA to increase the tonicity elevated the basal frequency of miniature end-plate potentials (MEPPs) in the frog. The hypertonic low calcium solution also increased the rate at which the MEPP frequency rose in response to tetanic stimulation and elevated the level of the maximum frequency, which approached an asymptote. Pretreatment with concanavalin A (con A) greatly reduced the elevation in the basal frequency produced by hypertonic solutions. However, tetanic stimulation gave the same results as in untreated preparations when the tonicity was increased. Pretreatment with colchicine before the con A treatment eliminated the blocking action of con A on the MEPP frequency when the preparation was exposed to hypertonic solutions. Tetanic stimulation produced increases in MEPP frequency similar to those observed in normal junctions immersed in hypertonic solutions. Caffeine elevated the basal level of the MEPP frequency. Tetanic stimulation in the caffeine solution caused the increase in the MEPP frequency; the higher the basal level rose, the higher the maximum level became. However, the rate at which the MEPP frequency rose remained unchanged. The present results indicate that hypertonicity increases not only the basal frequency of MEPPs but also the slope at which the MEPP frequency is elevated by tetanic stimulation, both mechanisms being different and that the rate and magnitude of the tetanic potentiation of MEPP frequency are not simply determined by the pre-tetanus frequency.

Action Potentials↗
PubMed1990

Mn and Mg influxes through Ca channels of motor nerve terminals are prevented by verapamil in frogs.

At frog neuromuscular junctions immersed in solutions containing 0.5 mM Mn2+, verapamil (40 microM) reduced the increase in miniature end-plate potential (MEPP) frequency produced by tetanic stimulation (50 Hz, 2 min) of the motor nerve to 5% of that in the absence of verapamil. In solutions containing 5 mM Mg2+, verapamil reduced the tetanic increase in MEPP frequency to 8% of that in the absence of verapamil. Verapamil added to solutions containing 0.15 mM Ca2+ decreased the tetanic rise in MEPP frequency to 6% of the control value. In low Ca2+ (nominally Ca2(+)-free) solutions, verapamil decreased the tetanic rise to 70% of the control value. The present results suggest that Mn2+ and Mg2+, as well as Ca2+, enter the nerve terminal through Ca2+ channels during nerve stimulation and promote transmitter release. In addition to its effect on the Ca2+ channel, verapamil at higher concentrations appears to have inhibitory effects on the acetylcholine-gated end-plate channel and on the Na+ channel as suggested by its depressive effects on the amplitudes of MEPPs, end-plate potentials and nerve terminal action potentials.

Action Potentials↗
PubMed1989

[Study on hybrid materials compounded with porous hydroxyapatite and culture cells. 1. Attachment and the invasion of cultured cells to porous hydroxyapatite].

The purpose of this study was to investigate the effects of hybrid material compounded with periodontal ligament cells on human teeth and porous hydroxyapatite. As the first step, we tried to produce hybrid materials compounded with periodontal ligament cells and porous hydroxyapatite, and to observe the attachment and invasion of periodontal ligament cells porous hydroxyapatite. Human periodontal ligament cells which had been scraped off the root with a disposable blade were cultured at 37 degrees C in alpha-MEM plus 10% fetal calf serum. The culture cells were attached to the porous hydroxyapatite in vitro. After 3 and 14 days of incubation, the specimens were fixed in gluteraldehyde and examined using SEM. Other specimens were embedded in paraffin and successive specimens were prepared for to remodelling of the attachment and invasion. Many cells attached to the P-HAP granules, and some cells invaded the P-HAP granules. The results suggest that when these hybrid materials are implanted in bone defects, the cells remain in the defect for a certain period, and exhibit the functions and characteristics of itself.

Bone Regeneration↗
PubMedDate not supplied

Evaluation of argyrophilic nucleolar organizer regions (AgNORs) in differentiated thyroid carcinoma as an indicator for disease recurrence.

Differentiated thyroid carcinoma (DTC) is one of the least aggressive cancers of the human malignancies, however, recurrent disease is occasionally found and is difficult to determine the risk for recurrence only by clinicopathological features. In the present study, we investigated argyrophilic nucleolar organizer regions (AgNORs) score, a well-known indicator for proliferative potential of the cancer cells, in 89 cases of DTC. In tumors with capsular invasion, or with extended contra-lateral lymph node metastasis, AgNORs score was significantly higher than in tumors without them, while was not correlated with age or gender of the patients, nor the histological type of the tumor (papillary or follicular). Disease recurrence was observed in one-third of the patients in high AgNOR score group (scored more than mean value +/- standard deviation) when the patients were divided into four groups according to the AgNOR score, and a significantly higher risk for disease recurrence was demonstrated in those cases with high AgNOR score than cases with lower score. These results clearly indicated the usefulness of AgNOR score in selecting the patients at high risk for disease recurrence. All 5 recurrent cases displayed local recurrence in high AgNOR score group, while 5 of 7 cases with low AgNOR score did in the manner of hematological metastasis. In conclusion, this method was technically simple and accurate giving an exact value in individual cases. Thus, we believe AgNOR score might be clinically applicable as a useful indicator for disease recurrence in DTC.

Adenocarcinoma, Follicular↗
PubMedDate not supplied

Mating in Bacillus thuringiensis can induce plasmid integrative prophage J7W-1.

Bacillus thuringiensis serovar israelensis, a bacterium which possesses plasmid transfer ability after mating, has been lysogenized by plasmid integrative phage J7W-1. The induction of phage in this J7W-1 lysogen was observed after mating with phage-insensitive strains, such as B. thuringiensis serovar thuringiensis, B. cereus and B. subtilis, as well as the phage-sensitive strain serovar israelensis. The phage induction was not observed after mating with B. thuringiensis strains AF101, serovar dendrolimus and serovar indiana. Because these strains are naturally associated with J7W-1 or its related phage, the data strongly suggest a constitutive expression of the repressor encoded by the prophage in these strains. However, the phage induction was observed in B. thuringiensis serovar aizawai, although it contained the J7W-1 DNA homologous region(s).

Bacillus Phages↗