Dependence of Threshold Switching Power on the Control-Light Wavelength in a Nonlinear Distributed-Feedback GaInAsP Waveguide

We demonstrate all-optical bistable switching by using orthogonally and parallelly polarized control light in a nonlinear distributed feedback GaInAsP waveguide. When the control light that is orthogonally polarized to the signal light is within its stopband, it is possible to extract the signal without using any external devices. Also, we investigate theoretically and experimentally the dependence of threshold switching power on the wavelength and polarization of control light.

Antinociceptive effects of bee venom acupuncture (apipuncture) in rodent animal models: a comparative study of acupoint versus non-acupoint stimulation

From a clinical perspective, the alternative forms of acupoint stimulation including electroacupuncture, moxibustion and acupressure appear to have more potent analgesic effects than manual needle acupuncture. Bee venom (BV) injection has also been reported to produce persistent nociceptive stimulation and to cause neuronal activation in the spinal cord. In previous study, we observed that BV stimulation into acupoint, namely BV acupuncture or Apipuncture, produced more potent anti-inflammatory and antinociceptive potency in rodent arthritis model as comparing with that of non-acupoint injection. Based on previous report, we decided to further investigate that BV injection into an acupoint produces antinociception as a result of its potent chemical stimulatory effect in both abdominal stretch assay and formalin test. Different doses of BV were injected into an acupoint or a non-acupoint 30 min prior to intraplantar formalin injection or intraperitoneal acetic acid injection. Using the abdominal stretch assay, we found that the high dose of BV (1:100 diluted in 20microl saline) produced a potent antinociceptive effect irrespective of the site of BV injection. In contrast the antinociceptive effect observed in both the writhing and formalin tests following administration of a low dose of BV (1:1000 diluted in 20microl saline) was significantly different between acupoint and non-acupoint sites. BV injection into an acupoint (Zhongwan, Cv. 12) was found to produce significantly greater antinociception than non-acupoint injection (10 mm from Zhongwan, Cv. 12) in the abdominal stretch assay. Similarly, in the formalin test, acupoint (Zusanli, St. 36) injection of BV produced more potent antinociception than non-acupoint injection (gluteal muscle). In contrast, BV injection into an arbitrary non-acupoint site on the back did not produce antinociception in either the writhing or formalin test. These results indicate that BV injection directly into an acupoint can produce a potent antinociceptive effect and suggest that this alternative form of acupoint stimulation (Apipuncture) may be a promising method for the relief of pain.

Neonatal intensive care unit outbreak caused by a strain of Klebsiella oxytoca resistant to aztreonam due to overproduction of chromosomal beta-lactamase

Klebsiella oxytoca strains resistant to both aztreonam and ceftriaxone were isolated from six neonates in a neonatal intensive care unit and water reservoirs of two humidifiers attached to the neonatal incubators. These isolates were assumed to be of the same clone because they were characterized by the same antimicrobial susceptibility and pulsed field gel electrophoresis patterns. It was established that the drug resistance was attributed to overproduction of chromosomally encoded Kl beta-lactamase. It was determined that an isolate (K. oxytoca H1) contained a high enzyme concentration (27microg/100microg of protein in enzyme extracts), at least 27 times higher than the control K. oxytoca N1. It was also demonstrated that isolates had a point mutation in the - 35 concensus region of the promotor gene of bla(OXY-2)leading to enzyme overproduction. Outbreaks caused by K1 hyperproducers have not previously been described.

Reciprocal expressions of cyclin E and cyclin D1 in hepatocellular carcinoma

Deregulation of the cell cycle by overexpression of G1 cyclins, cyclin E and cyclin D1 genes, has been demonstrated to be a prerequisite for the development of human cancer. Recently, cyclin E is proposed to be sufficient for the progression of the G1 cell cycle without cyclin D1. Here we show that the proposed model system was specifically present in human hepatocellular carcinoma (HCC) unlike other human cancers. Of 31 HCC tissues analyzed, 21 (67.7%) exhibited an overexpression of cyclin E protein. In contrast to cyclin E gene expression, cyclin D1 expression was strongly downregulated in 19 (61.2%) HCCs. Interestingly, 65% of HCC tissues with overexpression of the cyclin E gene exhibited downregulation of cyclin D1, suggesting reciprocal deregulation of these cyclins in the G1 progression of the cell cycle. Southern blot analysis proved the amplification of cyclin E gene in HCC with a high level of overexpression. The present findings suggest that the reciprocal deregulation of cyclin E lacking cyclin D1 expression might play a role in G1 progression and the development of HCC.

Cadmium decreases gap junctional intercellular communication in mouse liver

Cadmium (Cd) is an environmental pollutant of increasing importance, due to industrialization, smoking, and the lack of effective therapy for Cd poisoning. The general population is exposed to Cd principally through food and water. The metal accumulates slowly in the liver and kidney, the target organs of acute and chronic Cd toxicity, respectively. We showed recently that liver is also a target organ for chronic Cd toxicity. Gap junctional intercellular communication (GJIC) is a means of maintaining cellular homeostasis in multicellular organisms. It involves the transfer of small, water-soluble molecules through intercellular channels (gap junctions), composed of proteins called connexins. The major connexins of liver (hepatocytes) are connexin 32 (Cx32) and connexin 26 (Cx26). Cd disrupts cellular homeostasis in the liver through its induction of necrosis, apoptosis, and cellular proliferation. It is to be expected, therefore, that Cd must exert some effect on GJIC. This study investigates Cd-induced alterations in GJIC, Cx32, and Cx26 expression, and in cytoskeletal actin, and relates the changes to apoptosis and cell proliferation induced by Cd in vivo. Mice were injected ip with 30 micromol Cd/kg, and were observed for up to 48 h. Other groups of mice were injected with 5-60 micromol Cd/kg and observed for 9 h. Blood and liver were harvested and used for analysis of GJIC, connexin expression, cytoskeletal actin, serum enzymes, and liver pathology. Cd produced a time- and dose-dependent inhibition of GJIC in liver, along with parallel decreases in the expression of Cx32 and Cx26. Cd also produced disruption and loss of cytoskeletal actin in liver in a time- and dose-dependent manner. These observations are discussed in relation to the toxicity of Cd, and possible mechanisms of induction of the GJIC-related alterations are presented.

Gap measurement by position-sensitive detectors

A system for measuring the gap in a proximity exposure tool of a plasma display panel (PDP) is developed that uses single or dual position-sensitive detectors (PSD's). The resolution of the gap distance is 0.5 mum, with a capture range of 500 mum. Signal processing is simple and fast and easy because analogous PSD's are used as the position sensors. One PSD is used to detect the position of the reference beam, which is reflected from the upper surface of the gap; the other PSD is used to detect the position of the signal beam, which is reflected from the lower surface of the gap. A charge-coupled-device sensor is also employed to monitor the reflected beams and the region of measurement. In the gap-measurement system that uses a single PSD, first the reference beam is incident upon the PSD and then the signal beam is incident upon the same PSD. Then the separation between the two beams is calculated from the position of the reference beam and from the average beam position.

Infestation status of head louse and treatment with lindane shampoo in children of primary school and kindergarten in Chinju-shi, Kyongsangnam-do, Korea

The infestation status of head louse among children attending primary schools and kindergartens in Chinju-shi, Kyongsangnam-do, Korea, was investigated between June and July 1999. Out of 2,288 children examined, 3.9% of boys (48/1,242) and 23.5% of girls (246/1,046) were infested with nits or adult/nymphs of lice. The effectiveness of lindane shampoo (1% gamma benzene hexachloride solution) was evaluated after one or two time applications to all the children infested. The negative conversion rate of pediculosis was 93.5%. Effective control measures are needed to control and prevent such ectoparasite infestation amongst children.

Assessment of body composition using dual energy x-ray absorptiometry in patients with liver cirrhosis: comparison with anthropometry

OBJECTIVES

The aim of this study was to evaluate changes of body composition in cirrhotic patients. Dual energy x-ray absorptiometry (DEXA) and anthropometry were used, and the values obtained were compared.

METHODS

Mid-arm fat and muscle areas were calculated by anthropometry in 66 cirrhotic patients and 94 healthy controls. In 37 of the cirrhotic patients and 39 of the controls, fat mass, lean soft tissue mass and bone mineral contents were measured with DEXA.

RESULTS

The number of cirrhotic patients with measured values below the fifth percentile of normal controls was 21 (31.8%) by mid-arm fat area, six (9.1%) by mid-arm muscle area, 15 (40.5%) by fat mass and 0 (0%) by lean soft tissue mass. The fat mass in cirrhotic patients was less than in controls, whereas lean soft tissue mass and bone mineral content were not different. Fat depletion was severe in Child-class C patients and with severe ascites. Mid-arm fat area and fat mass showed close correlation (r = 0.85, p < 0.01), but mid-arm muscle area and lean soft tissue mass showed poor correlation (r = 0.32, p < 0.05).

CONCLUSION

Cirrhotic patients showed lower fat component, with preserved lean soft tissue mass and bone mineral content. In clinical practice, the measurement of mid-arm fat area was useful for the assessment of fat mass.

Emerging resistance of anaerobic bacteria to antimicrobial agents in South Korea

In previous studies, Bacteroides fragilis group organisms isolated from Korean patients were more frequently resistant to various antimicrobial agents, including clindamycin, than were isolates in other countries. A recent report of increased resistance of Peptostreptococcus species prompted us to include such isolates in a study of antimicrobial susceptibility. anaerobes isolated in 1994 at a tertiary care hospital in Seoul were tested by agar dilution method. None of the B. fragilis group organisms were resistant to imipenem, cefoxitin, chloramphenicol, or metronidazole. However, 6.7% were resistant to ampicillin/sulbactam, 20.2% to cefotetan, 30.3% to piperacillin, 48.3% to cefotaxime, and 42.7% to clindamycin. Almost all of the Clostridium perfringens isolates were susceptible to all of the agents tested, except tetracycline. Peptostreptococcus isolates were susceptible to piperacillin, cefotaxime, and imipenem, while 7.4% were resistant to penicillin G, cefotetan, and metronidazole, and 25.9% were resistant to clindamycin. The isolates resistant to penicillin G, cefotetan, and metronidazole were identified as Peptostreptococcus anaerobius. In conclusion, besides the well-known high rate of resistance of B. fragilis group organisms to clindamycin, the emergence of resistance of Peptostreptococcus species isolates to beta-lactam drugs has become obvious in Korea.

Nonspecific interstitial pneumonia/fibrosis: clinical manifestations, histologic and radiologic features

OBJECTIVES

Customarily used classification of IPF did not satisfy a sizable group of patients with IPF that in the past had been lumped with UIP and now currently has begun to be recognized as nonspecific interstitial pneumonia/fibrosis (NIP). There are few reports about the clinical features of NIP.

METHODS

The pathologic slides of 66 patients having open lung biopsy (OLB) for the differential diagnosis of interstitial lung diseases (ILD) from 1984 to 1995 were reviewed. Seven cases were confirmed as NIP. The clinical record, pulmonary function tests (PFT), chest PA and HRCT were reviewed and analysed retrospectively.

RESULTS

Six patients with NIP were female. The median age was 56 years. Mean duration of symptoms was 4 months. Five patients had systemic flu-like symptoms, the most common respiratory symptom was gradual dyspnea. Two patients revealed a mild degree of anemia. Four cases had leukocytois of more than 10,000/mm3. ESR and CRP O.K. elevated in all measured cases. Anti-nuclear antibody (ANA) was positive in three of six patients and ds-DNA antibody was positive in one of six patients. Restrictive pattern of PFT was predominant. Diffusion capacity of carbon monoxide (DLCO) decreased markedly. In bronchoalveolar lavage (BAL), total cell counts elevated about three times of normal value. On differential counts of BAL cells, lymphocytes, neutrophils and eosinophils were higher than those of normal controls. The prominent finding of chest radiology was bilaterally patchy opacifications in parenchyme of lower lung zones. On HRCT, bilaterally patchy areas of ground-glass attenuation and/or areas of alveolar consolidation were commonly shown. The number of pathologic type was one case of group I, four cases of group II and two cases of group III. The average period from diagnosis to the last follow-up was 24.8 months. Five patients were clinically recovered to the previously well-being state.

CONCLUSION

Patients with NIP had different clinical features from UIP, AIP and DIP. They also had characteristic findings of radiology and their prognosis seems to be better than UIP.

Use of a 64 channel computerized cardiac mapping system in arrhythmia surgery

A multipoint and computerized intraoperative mapping system has been known to be of value in improving the results of surgery for cardiac arrhythmia. It shows great potential as a new tool in the surgical intervention of the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, it also enhances the ability of the investigators to map and ablate the sometimes fleeting automatic atrial tachycardia. The authors developed a 64 channel computerized cardiac mapping system using a microcomputer (Macintosh IIx) and this has been used for basic research in cardiac electrophysiology as well as in arrhythmia surgery. In this system, bipolar electrograms are obtained from 64 different cardiac sites simultaneously at a sampling rate of 1 Ksample/sec and with a continuous and total data storage of up to 30 seconds. When the reference electrode is selected, delay time from the reference point is displayed on a two dimensional diagram of the heart. This system was used in one patient who underwent a surgical ablation of a ventricular tachycardia in whom we observed a ventricular activation sequence involving a variety of rhythms over several minutes. The system design permits easy expansion to a simultaneous sampling from 256 sites. This 64-channel mapping appeared to have the potential to be of great help in our understanding of cardiac arrhythmia as well as in its diagnosis and surgical treatment.

Decay studies of DMPO-spin adducts of free radicals produced by reactions of metmyoglobin and methemoglobin with hydrogen peroxide

The 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin adduct of myoglobin (Mb) or hemoglobin (Hb) was formed when metmyoglobin (MetMb) or methemoglobin (MetHb) reacted with H2O2 in the presence of DMPO, and both decayed with half-life of a few minutes. The DMPO spin adduct of Mb decayed with biphasic kinetics with k1 = 0.645 min-1 and k2 = 0.012 min-1, indicating that the spin adduct consisted of two kinetically heterogeneous species, stable and unstable ones. The DPMO spin adduct of Hb, however, was homogeneous. Decay of both spin adducts was accelerated in the presence of tyrosine, tryptophan or cysteine, but not phenylalanine, methionine or histidine. The decay obeyed the first order kinetics at varying concentrations of the spin adducts. The decay was accelerated by denaturation and proteolysis of protein moiety. The decay rate was not affected by the extra addition of MetMb or MetHb to each spin adduct. The decay rate of the spin adduct of Mb was increased by hematin in the presence of H2O2 and decreased by catalase. Decay of stable spin adduct of Mb, however, was not significantly changed under any experimental conditions used. These results led us to conclude that instability of the DMPO-spin adducts of Mb and Hb is due to intramolecular redox reactions between the spin adducts and amino acid residues and/or products of the reaction between heme and H2O2.