A 16-year survey of changes in bacterial isolates associated with chronic suppurative otitis media

Bacteria were isolated and cultured from the ears of outpatients with chronic suppurative otitis media (OMC) who attended the otologic clinics of Kyushu University Hospital from 1976 to 1991. Bacterial isolates were analyzed retrospectively to determine their incidences and antibiotic sensitivities. Staphylococcus aureus and Pseudomonas aeruginosa were the most commonly isolated organisms. The incidence of S. aureus infections gradually rose over 16 years, while the incidence of Proteus infections gradually declined. The frequency of isolation of glucose non-fermenting gram-negative rod (NF-GNR) species, fungi and anaerobic bacteria gradually increased. The species of bacteria isolated from OMC cases with acute and chronic infections, cholesteatoma and postoperative infections were compared. Over the 16 years, the isolation of S. aureus increased in frequency. The differences in each type of OMC ceased to exist. S. aureus were quite sensitive to most of the antibiotics tested, whereas Ps. aeruginosa and NF-GNR showed poor sensitivity.

Profiles of resting potentials across the stria vascularis in kanamycin-deafened guinea pigs

The resting potentials of the marginal cells in the stria vascularis of the guinea pig were determined from changes in the combined electrode-tissue resistance of the electrode. The resistance of the electrode was 45.5 +/- 16.0 M omega (n = 20) before penetration of the stria vascularis and 46.7 +/- 17.3 M omega (n = 20) after penetration. The resistance drops across the luminal membrane of the marginal cells were 46.0 +/- 22.6 M omega (n = 12) in kanamycin-deafened guinea pigs and 54.5 +/- 33.1 M omega (n = 9) in normal guinea pigs. The endocochlear potential (EP) and resting potentials in the marginal cells were 90.1 +/- 6.0 mV (n = 14) and 70.4 +/- 11.3 mV (n = 14) in kanamycin-deafened guinea pigs and 84.8 + 5.1 mV (n = 29) and 74.7 +/- 11.7 mV (n = 29) in normal guinea pigs. The resting potentials in the marginal cells decreased gradually and were approximately 0 mV around 20 min after anoxia in both kanamycin-deafened and normal guinea pigs. These changes were comparable to those of EP in kanamycin-deafened guinea pigs during anoxia. The mechanism of the EP in kanamycin-deafened guinea pigs is discussed.

Argyrophilic nucleolar organizer regions as a prognostic indicator of laryngeal carcinomas

Nucleolar organizer regions (NORs) were studied in surgically removed specimens from 76 patients with squamous cell carcinomas of the larynx using an argyrophilic (Ag) staining technique. The mean number of AgNORs per nucleus was 4.3 +/- 1.38 (SD). The mean AgNOR number for T1 or T2 disease was statistically lower than that for T3 or T4 lesions (P < 0.05). The mean AgNOR number was lower in patients with N0 disease than in patients with N1 or N2 or N3 tumors (P < 0.05). There was also a statistically significant difference between the mean AgNOR number for stage II and stage III disease (P < 0.01), for stage III and stage IV disease (P < 0.05), but not for stage I and stage II disease. According to the histological grading, there was a significant difference between the mean AgNOR number for the well-differentiated and moderately differentiated tumors (P < 0.05), and for the moderately differentiated and poorly differentiated types (P < 0.01). These results suggest that the number of AgNORs in the nucleus is a significant indicator of laryngeal carcinomas.

Preliminary findings of chromosomal alterations and expression of cell cycle genes in head an neck tumors

The genesis and progression of malignant tumors may be related to certain somatic mutations and the accumulation of multiple chromosomal alterations. Using four freshly resected malignant tumors, we investigated the relationship between chromosomal alteration and expression of cell cycle regulatory genes. Specimens of thyroid hyperplasia and normal thyroid tissue were also investigated. As cell cycle regulating genes, we chose the cdc2 gene that encodes the p34cdc2 protein kinase, a major kinase of the cell cycle, and the RCC1 gene that is essential for coupling between S and M phases. Three of the malignant tumors contained cells with chromosomal alterations, including one polyploid and two aneuploid. The DNA content of cells in thyroid hyperplasia was the same as in the normal gland. The amount of p34cdc2 protein was very low in cells of both normal thyroid and hyperplastic tissue, and grew very slowly as compared with malignant tumors. There was no significant relationship between the amount of RCC1 and ploidy pattern.

Neural projections from the frontal cortex to the oculomotor nucleus: an anatomical study using retrograde axonal, anterograde axonal and transneuronal transport of wheat germ agglutinin-conjugated horseradish peroxidase in cats

Neural projections from the frontal cerebral cortex to the oculomotor nucleus (3N) were investigated in 1- to 2-year-old cats by retrograde and anterograde axonal and transneuronal transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). Following injection of WGA-HRP into the 3N area and its surrounding tissues, retrogradely labeled cells were observed in the anterior sigmoid gyrus, ventral bank of the cruciate sulcus, medial and lateral walls and base of the presylvian sulcus, gyrus rectus and gyrus proreus. Following injection of WGA-HRP into these frontal cortical areas, anterogradely labeled nerve terminals were observed in the mesencephalic periaqueductal gray matter (PAG) just overlying the 3N. Only a few terminals were observed within the 3N. Following injection of WGA-HRP into the extraocular muscles of 1-month-old kittens, transneuronally labeled small cells were observed in the PAG just overlying the 3N and in the mesencephalic reticular formation, ventrolateral to it. These small cells may represent intercalated neurons of the cortico-oculomotor projections in the cat.

Segregation analysis of IgE responses to Cryptomeria japonica pollen antigen in vivo

The IgE response to Cryptomeria japonica pollen antigen (CPAg) in vivo was determined by radioimmunoassay of the plasma of 525 members from 98 families with known nasal allergies. Based on responses, patients were classified into a non-responder or low-responder group (non/low) and a high-responder group. Segregation analysis revealed that the IgE non/low responsiveness to CPAg involved a single dominant trait. The gene frequency was calculated to be 0.44-0.60. The IgE non/low response to CPAg was found to be mediated by CPAg-specific suppressor T cells. These findings demonstrated that the phenotypic variation of IgE responsiveness to CPAg is not due the immune response gene, but rather is mediated by the immune suppression gene for CPAg, via CPAg-specific suppressor T cells.

The seven amino acids of human RAMP2 (86) and RAMP3 (59) are critical for agonist binding to human adrenomedullin receptors

When co-expressed with a receptor activity-modifying protein (RAMP) accessory protein, calcitonin receptor-like receptor (CRLR) can function as a calcitonin gene-related peptide receptor (CRLR-RAMP1) or an adrenomedullin (AM) receptor (CRLR-RAMP2/3). Here we report on the structural domain(s) involved in selective AM binding that were examined using various RAMP chimeras and deletion mutants. Co-expression of chimeric RAMPs and CRLR in HEK293 cells revealed that residues 77-101, situated in the extracellular N-terminal domain of human RAMP2 (hRAMP2), were crucial for selective AM-evoked cAMP production. More detailed analysis showed that deletion of hRAMP2 residues 86-92 significantly attenuated high-affinity (125)I-AM binding and AM-evoked cAMP production despite full cell surface expression of the receptor heterodimer and that deletion of hRAMP3 residues 59-65 had a similar effect. There is little sequence identity between hRAMP3 residues 59-65 and hRAMP2 residues 86-92; moreover, substituting alanine for Trp(86) (Ala(87)), Met(88), Ile(89), Ser(90), Arg(91), or Pro(92) of hRAMP2 had no effect on AM-evoked cAMP production. It thus seems unlikely that any one amino acid residue is responsible for determining selective AM binding or that AM binds directly to these peptide segments. Instead these findings suggest that the respective seven-amino acid sequences confer selectivity either by directly contributing to the structure of ligand binding pocket or by allosteric modulation of the conformation of CRLR.

C-shape extended transconjunctival approach for the exposure and osteotomy of traumatic orbitozygomaticomaxillary deformities

In the treatment of post-traumatic deformities of the orbitozygomaticomaxillary complex resulting from trauma, the most appropriate exposure must be used. The choice of exposures includes the bicoronal approach and the periorbital incisions. When the whole orbitozygomatic complex is malpositioned, the bicoronal approach is desirable; this can be combined with buccal and eyelid incisions. However, the bicoronal approach is complicated by a longer duration of operation time, post-surgical scars that tend to show, and potential damage to the temporal branch of the facial nerve. A new approach using a C-shape extended transconjunctival approach is possible to have one field of vision to osteotomize the frontozygomatic suture, the lateral orbital wall, inferior orbital rim, lateral maxillary buttress, and zygomatic arch. It takes less operating time and the post-surgical scars are shorter than the bicoronal approach.

In vivo evaluation of a novel porous hydroxyapatite to sustain osteogenesis of transplanted bone marrow-derived osteoblastic cells

Biosynthetic bone grafts are considered to contain one or more of three critical components: osteoprogenitor cells, an osteoconductive matrix, and osteoinductive growth factors. The basic requirements of the scaffold material are biocompatibility, mechanical integrity, and osteoconductivity. A major design problem is satisfying these requirements with a single composite. In this study, we hypothesize that one composite that combines bone marrow-derived osteoblasts and a novel mechanical reinforced porous hydroxyapatite with good biocompatibility and osteoconductivity (HA/BMO) can reach these requirements. A novel sintered porous hydroxyapatite (HA) was prepared by the following procedures. The HA slurry was foamed by adding polyoxyethylenelaurylether (PEI) and mixing. The pores were fixed by crosslinking PEI with diepoxy compounds and the HA porous body was sintered at 1200 degrees C for 3 h. The HA sintered porous body had a high porosity (77%), and was completely interconnected. Average pore diameter was 500 microm and the interconnecting path 200 microm in diameter. The compressive (17 MPa) and three-point bending (7 MPa) strengths were high. For in vivo testing, the 2-week subcultured HA/BMO (+) composites were implanted into subcutaneous sites of syngeneic rats until 8 weeks after implantation. These implants were harvested at different time points and prepared for the biochemical analysis of alkaline phosphatase activity (ALP) and bone osteocalcin content (OCN), and histological analysis. ALP and OCN in the HA/BMO group were much higher than those in the HA without BMOs control group 1 week after implantation (p < 0.001). Light microscopy revealed mature bone formation in the HA/BMO composite 4 weeks after implantation. In the SEM study, mineralized collagenous extracellular matrix was noted in HA/BMO composite 2 weeks after implantation with numbers of active osteoblasts. We conclude that the composite of the novel HA and cultured BMOs has osteogenic ability in vivo. These results provide a basis for further studies on the use of this composite as an implant in orthopaedic surgery.

Location and length of arteriovenous fistulas around axial-pattern skin-flap pedicles

The importance of the location of a surgically-created arteriovenous fistula around the pedicle (both distal and proximal) on the viability of rat skin flaps was investigated. The animals were randomly divided into four groups. Group 1 included bilateral standard island groin flaps. The right side flap was used as a control. On the left side, after elevation of the flap, an X-type arteriovenous fistula greater than 1 mm (up to 2 mm) in length was created distal to the pedicle, and just before the bifurcation of the common femoral vessels. In Group 2, the flap was an axial-pattern medially-based peninsular flap, including the same vessels. In this group also, two flaps were elevated bilaterally, and the right side was used as a control; on the left side, an X-type arteriovenous fistula the same length as in Group 1 was also created distal to the pedicle. In both groups, all other branches of the common femoral vessels were kept intact. In a second part of the study, two other animal groups were used to clarify the importance of the length of the arteriovenous fistula on the viability of skin flaps. In Group 3, the model was the same as in Group 1, but the fistula was 1 mm in length. In Group 4, the length of the fistula was 1 mm, and its location was on the common femoral vessels proximal to the pedicle, using the same flap model. Flow values were measured repeatedly using a laser Doppler flowmeter. Histopathologic studies were also done. There are three important points arising from these studies. 1). The location of an X-type arteriovenous fistula around an island skin flap pedicle seems to be more important than diameter. An arteriovenous fistula proximal to the pedicle is more hazardous than an arteriovenous fistula distal to the pedicle, regarding island skin-flap viability. 2). However, the length of the fistula is also important, and an arteriovenous fistula distal to the pedicle, with a sufficiently long length, is not devoid of harmful effects. It is also clear that the larger the fistula, the greater the systemic effects. 3). An island skin flap with an arteriovenous fistula distal to its pedicle might be a useful model to study the relationship between skin-flap viability and edema formation.

A longitudinal study of disturbances of the hypothalamic-pituitary-adrenal axis in women with progestin-negative functional hypothalamic amenorrhea

OBJECTIVE

To longitudinally evaluate disturbances of the hypothalamic-pituitary-adrenal (HPA) axis in women with secondary progestin-negative hypothalamic amenorrhea.

DESIGN

Retrospective cohort study.

SETTING

Yokohama City University, Yokohama, Japan.

PATIENT(S)

Twenty-four women with progestin-negative hypothalamic amenorrhea.

INTERVENTION(S)

Administration of human corticotropin-releasing hormone (hCRH) and treatment with a combination of estrogen and progesterone.

MAIN OUTCOME MEASURE(S)

Plasma cortisol and ACTH concentrations and period required for recovery from amenorrhea.

RESULT(S)

Plasma ACTH concentrations 30 and 60 minutes after injection of hCRH and the percent maximum increment (%Cmax) of ACTH were significantly lower in the amenorrheic patients compared with the control group patients. The basal cortisol was significantly higher, and the %Cmax of cortisol was significantly lower. In the 16 patients who recovered from amenorrhea, there was a significant positive correlation (Y = 1.93X-10.8, r = 0.629) between the basal cortisol concentrations (X) and the period for recovery (Y). The serum E2 gradually increased before recovery, and this E2 increase was preceded by changes in the plasma cortisol concentration and the %Cmax values of cortisol and ACTH.

CONCLUSION(S)

The CRH test might be useful for evaluating the roles of stress and for estimating the period required for recovery in hypothalamic amenorrhea.

Surgical program for craniosynostosis using three-dimensional solid model, combined with autologous blood transfusion in a Japanese craniofacial unit

Since April 1997 at St. Mary's Craniofacial Unit, simulated surgery using a three-dimensional solid model made preoperatively was carried out, which enable sufficient autologous blood banking before the surgery. This study was conducted in eight patients presenting with plagiocephaly, brachycephaly, and oxycephaly consisting of simple craniosynostosis and syndromic craniosynostosis. Four cases (numbers 1-4) conducted with simulated surgery using three-dimensional solid models and fronto-orbital advancement with reshaping, as well as autologous blood transfusion were selected for the later-term group. For the first-term group, four cases (numbers 5-8) that were performed before the introduction of the abovementioned treatment were selected. The later-term group compared with the first-term group showed a decrease in operating time by an average of 1 hour, blood loss during surgery by 90 ml, and one fifth the amount of homologous blood transfusion. Also, 2 cases in the later-term group (cases 3 and 4) were able to avoid homologous blood transfusion, and they had autologous blood transfusion of 30 to 33 ml/kg. The surgical techniques will be improved with repeated cases of simulated surgery, aiming for the minimum invasive surgery. Also, the use of autologous blood transfusion is expected to increase as a less invasive surgery.

Asymmetric colocalization of Flamingo, a seven-pass transmembrane cadherin, and Dishevelled in planar cell polarization

The Drosophila wing provides an appropriate model system for studying genetic programming of planar cell polarity (PCP) [1-4]. Each wing cell respects the proximodistal (PD) axis; i.e., it localizes an assembly of actin bundles to its distalmost vertex and produces a single prehair. This PD polarization requires the redistribution of Flamingo (Fmi), a seven-pass transmembrane cadherin, to proximal/distal cell boundaries; otherwise, the cell mislocalizes the prehair [5]. Achievement of the biased Fmi pattern depends on two upstream components in the PCP signaling pathway: Frizzled (Fz), a receptor for a hypothetical polarity signal, and an intracellular protein, Dishevelled (Dsh) [6-8]. Here, we visualized endogenous Dsh in the developing wing. A portion of Dsh colocalized with Fmi, and the distributions of both proteins were interdependent. Furthermore, Fz controlled the association of Dsh with cell boundaries, which association was correlated with the presence of hyperphosphorylated forms of Dsh. Our results, together with a recent study on Fz distribution [9], support the possibility that Fz, Dsh, and Fmi constitute a signaling complex and that its restricted localization directs cytoskeletal reorganization only at the distal cell edge.

rDrak1, a novel kinase related to apoptosis, is strongly expressed in active osteoclasts and induces apoptosis

This is the first report of a novel serine/threonine kinase, rabbit death-associated protein (DAP) kinase-related apoptosis-inducing protein kinase 1 (rDRAK1), involved in osteoclast apoptosis. We searched for osteoclast-specific genes from a cDNA library of highly enriched rabbit osteoclasts cultured on ivory. One of the cloned genes has a high homology with human DRAK1 (hDRAK1), which belongs to the DAP kinase subfamily of serine/threonine kinases. By screening a rabbit osteoclast cDNA library and 5'-RACE (rapid amplification of cDNA ends), we obtained a full length of this cDNA, termed rDRAK1. The sequencing data indicated that rDRAK1 has 88.0, 44.6, 38.7, and 42.3% identity with hDRAK1, DAP kinase, DRP-1, and ZIP (zipper-interacting protein) kinase, respectively. To clarify the role of DRAK1 in osteoclasts, we examined the effect of three osteoclast survival factors (interleukin-1, macrophage colony-stimulating factor, and osteoclast differentiation-inducing factor) on rDRAK1 mRNA expression and the effect of rDRAK1 overexpression on osteoclast apoptosis. The results suggested that these three survival factors were proved to inhibit rDRAK1 expression in rabbit osteoclasts. After transfection of a rDRAK1 expression vector into cultured osteoclasts, overexpressed rDRAK1 was localized exclusively to the nuclei and induced apoptosis. Hence, rDRAK1 may play an important role in the core apoptosis program in osteoclast.

Attenuation of liver and lung injury after hepatic ischemia and reperfusion by a cytokine-suppressive agent, FR167653

BACKGROUND

Hepatic ischemia/reperfusion (I/R) injury is an important clinical problem and leads to the release of the proinflammatory cytokines, TNF-alpha and IL-1. These cytokines play important roles in the induction of polymorphonuclear neutrophil (PMN) activation and infiltration, and induce not only localized hepatic injury but also remote organ injury, especially pulmonary injury. Using a total hepatic ischemia model in rats, we tested our hypothesis that suppression of TNF-alpha and IL-1 by FR167653 ameliorates I/R injury in the liver and lung.

METHODS

Male Wistar rats, weighing 240-280 g, were divided into 3 groups, an FR group, a control group and a sham group. In the FR group, FR167653 (1 mg/kg/h) was administered continuously to the animals for 30 min prior to the onset of ischemia and for 2 h after reperfusion. The control group received normal saline. A porto-systemic shunt was placed between the cecal branch of the portal vein and the jugular vein, and total hepatic ischemia was produced for 90 min. The sham group was treated with placement of the porto-systemic shunt only. The 1-week survival rate, liver enzyme activity, hepatic tissue blood flow (HTBF), cytokine mRNA expression, myeloperoxidase (MPO) activity and histological results were studied.

RESULTS

The 1-week survival rate and HTBF were significantly higher in the FR group than in the control group. Serum AST, ALT, and LDH levels were significantly lower in the FR group at 30 min, 1 h and 3 h after reperfusion. MPO levels in liver and lung tissue were also significantly lower in the FR group. The expression of IL-1beta mRNA remarkably decreased up to 6 h after reperfusion in the FR group.

CONCLUSIONS

We concluded that the inflammatory cytokines, IL-1beta, play important roles in hepatic I/R injury. FR167653 might ameliorate I/R injury and be useful in liver surgery with ischemia.

[Survey of consciousness of community residents regarding the community life of disabled persons with service dogs]

PURPOSE

Service dogs have received much attention as effective choices for promoting participation in society of disabled persons. The purpose of this study was to obtain the fundamental data to prepare guidelines regarding service dogs use in community life, by making clear the problems in terms of public health and community welfare through a survey of attitudes towards service dogs in community residents.

METHODS

Study 1 was conducted as follows. The subjects were 423 community residents between their teens and seventies who participated in health and welfare lectures in 4 metropolitan areas. A questionnaire survey was conducted just after watching a promotion video about service dogs, including several items on aspects not accept, were anxious about or were unpleasant in the case of community life of a disabled person and a service dog. Study 2 was as follows. A questionnaire survey was conducted inside a supermarket in the central part of Tokyo. One group of subjects were 103 shopping customers who witnessed a shopping scene featuring a disabled person with her service dog, and the other subjects were 84 customers who were not witnessed to the scene. The same survey was simultaneously performed for impression about the shopping scene.

RESULTS

Study 1 showed that 31.8% of all the respondents replied that they had some knowledge of service dogs before watching the video. A total of 20.4% (32.5% of the elderly) replied that there were places where service dogs should not enter. Concretely speaking, these included restaurants for 7.3-22.5% and medical institutions for 8.5-12.5% of the respondents. A third of all the respondents (51.3% of older persons) replied they could not endure some actions by service dogs, concretely "carrying food in the mouth" was highly pointed out by 27.3%. Zoonosis (15.3-19.0%), hair scattering (9.5-21.3%), injuries (4.4-7.4%) were also pointed out as main sources of anxiety or uncomfortable feelings. Such negative opinions were especially apparent among those aged 60 years and older. Also, 44.1% knew some disabled person. Cross tabulation showed those who had experience of taking care of a dog were significant less anxious about "vague anxiety or discomfort," and "zoonosis" than those who had not (P < 0.01). On the other hand, most of both witness (79.6%), and non-witness groups (81.0%) replied that it was heartwarming that the service dog assisted with shopping. None expressed discomfort about the presence of "service dog" inside the supermarket. In terms of carrying a commodity in the mouth, 92.2% and 89.1% in both groups replied that they don't mind, especially if safety was guaranteed for public health, and 91.3% and 95.2% in both groups replied that they had no other problems. Moreover, none of them would not entering stores. Significant differences were seldom in replies between the witness and non-witness groups.

CONCLUSION

Although the respondents were extremely affirmative regarding the image of service dogs, it became clear that anxiety about public health aspects such as "zoonosis" or "utilization of medical institutions" was persisting. On the whole, negative opinions were more apparent in the elderly.

Developmental roles and molecular characterization of a Drosophila homologue of Arabidopsis Argonaute1, the founder of a novel gene superfamily

BACKGROUND

Arabidopsis Argonaute1 (AGO1) is the founder of a novel gene superfamily that is conserved from fission yeasts to humans. AGO1, and several other members of this superfamily are necessary for stem cell renewal or RNA interference. However, little has been reported about their roles in animal development or about the molecular activities of any of the members.

RESULTS

We have isolated a Drosophila homologue of AGO1, dAGO1, in our attempt to search genetically for regulators of Wingless (Wg) signal transduction. dAGO1 is broadly expressed in the embryo and the imaginal disc. dAGO1 over-expression at wing margins suggested that it behaves as a positive regulator in the genetic background employed. Loss-of-function mutations of dAGO1, unexpectedly, did not give typical segment polarity phenotypes of the wg class; instead, dAGO1 maternal and zygotic mutant embryos showed developmental defects, with malformation of the nervous system being the most prominent. The mutant decreased in the numbers of several types of neurones and glia examined. The dAGO1 protein was distributed in the cytoplasm and co-sedimented with poly(U)- or poly(A)-conjugated beads.

CONCLUSION

Our results suggest that the dAGO1 protein exerts its developmental functions by binding to RNA either directly or indirectly.

Mechanical strain effect on bone-resorbing activity and messenger RNA expressions of marker enzymes in isolated osteoclast culture

Adaptive modeling and remodeling are controlled by the activities of osteoblasts and osteoclasts, which are capable of sensing their mechanical environments and regulating deposition or resorption of bone matrix. The effects of mechanical stimuli on isolated osteoclasts have been scarcely examined because it has proven to be difficult to prepare a number of pure osteoclasts and to cultivate them on mineralized substratum during mechanical stimulation. Recently, we developed an apparatus for applying mechanical stretching to the ivory slice/plastic plate component on which cells could be cultured. The loading frequency, strain rate, and generated strain over an ivory surface could be controlled by a personal computer. Using this apparatus, we examined the role of mechanical stretching on the bone-resorbing activity of the osteoclasts. Mature and highly enriched osteoclasts were cultured for 2, 12, and 24 h on the ivory/plate component while being subjected to intermittent tensile strain. The stretched osteoclasts showed enhanced messenger RNA (mRNA) expression levels of osteoclast marker enzymes, tartrate-resistant acid phosphatase (TRAP), and cathepsin K and increases of resorbed-pit formation, suggesting that the mechanical stretching up-regulated the bone-resorbing activity of the osteoclasts. A stretch-activated cation (SA-cat) channel blocker significantly inhibited the increases of the mRNA level and pit formation after 24 h of stretching. This study suggested the possibility that the mature osteoclasts responded to mechanical stretching through a mechanism involving a SA-cat channel in the absence of mesenchymal cells and, as a result, up-regulated their bone-resorbing activity.

Immortalized gonadotropin-releasing hormone neurons (GT1-7 cells) exhibit synchronous bursts of action potentials

Although it has been assumed that synchronized firing of gonadotropin-releasing hormone (GnRH) neurons is necessary for pulsatile GnRH secretion, there is no clear evidence for this. In the present study we simultaneously recorded spontaneous action potentials from multiple cells. Immortalized GnRH neurons (GT1-7 cells) were cultured on a multi-electrode dish (MED) and action potentials recorded by an extracellular recording method. One to two weeks after the beginning of culture, spontaneous action potentials appeared, exhibiting bursts composed of 5-10 action potentials. Burst activity was intermittent and periodic with mean burst intervals of 13.3 s. Furthermore, burst activity was recorded almost simultaneously from several micro-electrodes, suggesting that electrical activities of GT1-7 cells were synchronized with each other. Periodic bursts were completely and reversibly blocked by 1-5 microM tetrodotoxin, indicating that voltage-dependent Na(+) channels are involved in their generation. gamma-Aminobutyric acid (GABA) given at a 10-microM concentration shortened inter-burst intervals, whereas 10 microM bicuculline lengthened them. Finally, the gap junctional blockers n-octyl alcohol (1 mM) and carbenoxolone (100 microM) reversibly blocked periodic burst activity. The present study provides direct evidence that the electrical activity of GT1-7 cells exhibits synchronous and periodic bursts composed of action potentials. In addition, endogenous GABA is involved in GT1-7 cells in determining burst frequency. Although the precise mechanism of synchronized burst activities needs to be clarified, gap junctional communications among GT1-7 cells are at least partially involved.

Enhanced expression of cyclin E and cyclin A in human hepatocellular carcinomas

BACKGROUND

Disruption of the G1/S check point leads to uncontrolled cell growth, resulting in the development of cancers.

MATERIALS AND METHODS

Cell cycle regulatory molecules were investigated in 33 surgically resected hepatocellular carcinoma (HCC) samples from 30 patients by Western blotting.

RESULTS

Enhanced expressions of cyclin E and cyclin A were detected at frequencies of 18/33 and 26/33 in HCCs, respectively, as compared with their neighboring noncancerous tissues. The enhanced expression of cyclin E, but not that of cyclin A, correlated with hyperphosphorylation of pRb and high frequency of Ki-67-positive cells. Thus, the HCCs with enhanced cyclin E expression probably contain a relatively large number of proliferating cancer cells.

CONCLUSIONS

The degree of cyclin E expression can be used as a prognostic parameter of HCC. In addition, cyclin E may become a molecular target in the treatment of HCCs.

A case of improved obstructive sleep apnea by distraction osteogenesis for midface hypoplasia of an infantile Crouzon's syndrome

We performed Le Fort III midfacial advancement with gradual distraction using internal devices on a 2-year 5-month-old boy with Crouzon's syndrome with associated severe obstructive sleep apnea. The device was not activated until 7 days after surgery, after which the distraction was initiated, 1 mm per day, and the midface was advanced 4 mm intraoperatively and distracted 12 mm postoperatively. A total advancement of 16 mm was obtained. The obstructive sleep apnea improved remarkably after the distraction. In infants and younger children with associated severe obstructive sleep apnea, advancement by distraction osteogenesis of the midface in Le Fort III maxillary osteotomy will be initially indicated to obviate tracheostomy improving the upper airway obstruction.