Using a heavy chain-loss hybridoma 26.4.1LL for studying the structural basis of immunoglobulin chain association

One of the mechanisms contributing to antibody diversity is created by the association of different heavy and light chains. The combinability of heavy and light chains has been studied previously in two systems: in vitro chain recombination and hybrid hybridoma. Here, a novel in vivo chain combination assay system involving a heavy chain-loss variant, 26.4.1LL, producing two kappa light chains (L(DEX) and L(MPC)) different in size is described. In conjunction with DNA transfection, immunoprecipitation and SDS-PAGE, the structural basis of noncovalent interaction between heavy and light chains can be elucidated systematically by examining the relative association tendency of a heavy chain with two light chains. To demonstrate the usefulness of this system, three stably transfected 26.4.1LL cell lines expressing gamma2b heavy chains, designated as H(DEX), H(CHI) and H(ARS), respectively, with structural interrelated variable regions were generated: H(DEX) differs from H(CHI) only in framework regions whereas H(CHI) differs from H(ARS) in complementarity-determining regions. The relative amounts (R values) of L(DEX) and L(MPC) associated with the heavy chains H(DEX), H(CHI) and H(ARS) in the assembled immunoglobulin molecules were found to be 1.02, 0.64 and 0.05, respectively, suggesting that the complementarity-determining regions and framework regions contribute equally to the V(L)-V(H) interaction. This conclusion is consistent with previous observations based on calculation of the buried area in the V(L)-V(H) interface, thus demonstrating the usefulness of this system.

Subject-domain approach to the study of air pollution effects on schoolchildren's illness absence

In this paper, the authors propose a new statistical modeling technique, the subject-domain approach, which is theoretically proven to be equivalent to the time-domain approach in detecting an association between exposure and response with time trends. The authors use an empirical data set from a school absence monitoring study conducted during the 1994-1995 school year in Taiwan to demonstrate this subject-domain approach's application to environmental epidemiologic studies. Because the subject-domain models can control the influential personal confounding factors in the models, they show greater statistical power than the traditional time-domain approaches in determining the relation between air pollution and illness absences. The authors' models found that the schoolchildren's risks of illness absence were significantly related to acute exposures to nitrogen dioxide and nitrogen oxides with a 1-day lag (p < 0.01) at levels below the World Health Organization's guidelines. By contrast, the authors could not detect significant associations between air pollution and schoolchildren's absenteeism using time-domain approaches. Such findings imply that the models built on subject domain may be a general solution to the problem of the ecologic fallacy, which is commonly encountered in environmental and social epidemiologic studies.

Nitric oxide mediates depressor responses by activation of N-methyl-D-aspartate receptors in the nucleus tractus solitarius of cat

Nitric oxide (NO) is involved in cardiovascular regulation and sympathetic nerve activity of the central nervous system (CNS). The nucleus tractus solitarius (NTS) is important to cardiovascular regulation. However, the physiological role of NO in cardiovascular regulation effecting through the NTS remains unclear. The purpose of this study is to investigate the effect of NO measured by in vivo voltammetry on the cardiovascular responses in NTS induced by N-methyl-D-aspartate (NMDA) in anesthetized cats. Extracellular NO concentration was monitored through a Nafion- and porphyrin-coated carbon fiber electrode, which has previously been demonstrated sensitive and selective to NO responses. Microinjection of NMDA into NTS elicited a dose-dependent decrease in cardiovascular responses associated with NO release. Following the dose-response curve, a dose of 3 nmol of NMDA was selected. Microinjection of NMDA into NTS produced depressor responses and NO release. These responses in NTS to NMDA were attenuated by pretreatment with a competitive antagonist, 2-amino-5-phosphonopentanoat (AP-5, 1 nmol), and methylene blue (MB, 1 nmol), an inhibitor of guanylate cyclase. These results suggest that NO is formed from NMDA activation in NTS and that NO diffuses out of neurons into the nearby target neurons to produce depressor response and NO release through cyclic guanosine monophosphate (cGMP) formation. In conclusion, NO mediates depressor response consequent to activation of NMDA receptors in neurons of NTS.

A comparison of the surface characteristics and ion release of Ti6Al4V and heat-treated Ti6Al4V

This work seeks to investigate the nanosurface characteristics and ion release for a Ti6Al4V alloy prepared by various methods (as received and heat treated at 1300 degrees C for 2 h) with three different passivation treatments (34% nitric acid passivation, 400 degrees C heating in air, and aging in 100 degrees C deionized water). The surface and nanosurface composition are not related to the surface passivation treatments and experimental materials as evaluated by energy dispersive spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses. After passivation and autoclaving treatments, the specimens were immersed in 8.0 mM ethylenediaminetetraacetic acid (EDTA) in Hank's solution and maintained at 37 degrees C for periods of time up to 16 days. The 400 degrees C treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the thicker thickness and rutile structure of the surface oxides. After soaking in Hank's-EDTA solution, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-16 day experimental period. The thicker oxides may be a factor in the improved dissolution resistance. Upon immersion, nonelemental Ca and P are both detected on the surfaces of all kinds of specimens by XPS analysis, and this could be explained by the existence of two types of hydroxyl groups (acidic and basic OH groups) on the oxide surface of the specimens.

Calcium and magnesium in drinking water and the risk of death from breast cancer

The relationship between mortality from breast cancer and the levels of calcium and magnesium in drinking water was examined using an ecological design. The study area consisted of 2.52 municipalities in Taiwan. Data on the levels of calcium and magnesium in drinking water were collected from the Taiwan Water Supply Corporation (TWSC). The age-standardized mortality rate (ASR) for breast cancer ( 1982-1991) was compared among municipalities with different levels of magnesium and calcium in drinking water. Weighted multivariate regression analysis was used, and after adjusting for fertility rates and urbanization, there was a significant inverse relationship between the levels of calcium and magnesium in drinking water and risk of death from breast cancer.

Preferential cytotoxicity of caffeic acid phenethyl ester analogues on oral cancer cells

As part of our previous search for new compounds with improved biological activities including antibiotic, antiviral, anti-inflammatory, and tumor growth inhibition activities, we synthesized some caffeic acid phenethyl ester (CAPE)-like compounds from commercially available caffeic acid. Nine chemicals were tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on the growth of buccal mucosal fibroblast (BF), oral submucosus fibroblast (OSF), neck metastasis of Gingiva carcinoma (GNM), and tongue squamous cell carcinoma (TSCCa) cells. CAPE and its ethyl analogue show significant cytotoxicity on OSF, GNM, and TSCCa cells, but not on BF cells. The results suggest that CAPE-like compounds may be potential chemotherapy agents against oral cancer.

Calcium and magnesium in drinking water and risk of death from prostate cancer

The possible association between the increased risk of prostate cancer and the levels of calcium and magnesium in drinking water from municipal supplies was investigated in a matched cancer case-control study in Taiwan. All eligible prostate-cancer deaths (682 cases) of Taiwan residents from 1987 through 1993 were compared with deaths from other causes (682 controls). The levels of calcium and magnesium in the drinking water of these residents were also determined. Data on calcium and magnesium levels in drinking water throughout Taiwan were obtained from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes, and the controls were pair-matched to the cases by year of birth and death. The adjusted odds ratios for prostate cancer death for those with higher magnesium levels in their drinking water, as compared to the lowest tertile, were 0.73 (95% CI = 0.51-1.03) and 0.64 (95% CI = 0.43-0.96), respectively. The adjusted odd ratios for the relationship between calcium levels in drinking water and prostate cancer were not statistically significant. The results of the present study show that there may be a significant protective effect of magnesium intake from drinking water and other dietary sources against the risk of prostate cancer development.

Female lung cancer mortality and sex ratios at birth near a petroleum refinery plant

This study was conducted to assess whether female mortality from lung cancer is associated with residence in communities adjacent to a petroleum refinery plant and whether petroleum air pollution could affect the sex ratios of births. The Kaohsiung Refinery of the Chinese Petroleum Corp. is the oldest oil refinery in Taiwan and is located between the Tso-Ying and the Nan-Tzu municipalities. Standardized mortality ratios (SMRs) for female lung cancer and sex ratios of births were calculated for each municipality for the years 1971-1996. Cumulative-sum techniques were used to detect the occurrence of changes in the SMRs. The study results show that mortality from female lung cancer rose gradually about 30 to 37 years after the operation of a petroleum refinery plant began. However, the association between exposure to the petroleum air pollution and abnormal sex ratios at birth was not significant.

An enhanced process for encapsulating aspirin in ethyl cellulose microcapsules by solvent evaporation in an O/W emulsion

An enhanced process for microencapsulating aspirin in ethylcellulose was demonstrated using an oil-in-water emulsification/solvent evaporation technique. Methylene chloride (CH2Cl2) was used as the dispersed medium and water as the dispersing medium. The recovered weight, particle size distribution, aspirin loading efficiency, and the aspirin release rate of microcapsules were analysed. The addition of appropriate amounts of non-solvent (n-heptane) prior to the emulsification increases the recovered weight, but decreases the size of the formed microcapsules. The addition of non-solvent also changes the microcapsule characteristics, resulting in a coarser surface and an increased release rate. Increasing the polymer (ethylcellulose) concentration in the dispersed phase increases the size of the microcapsules, the recovered weight, and loading efficiency, but decreases the release rate. The release rate follows first-order kinetics during the first 12 h, suggesting a monolithic system with aspirin uniformly distributed in the microcapsule.

Fixed erythrodysaesthesia plaque due to intravenous injection of docetaxel

Docetaxel (Taxotere), a semisynthetic taxoid, acts as an antimicrotubule agent and is considered to have great potential in the treatment of non-small cell lung cancer, advanced breast cancer, ovarian cancer and some other tumours. Well-recognized side-effects include dose-limiting neutropenia, fluid retention, myalgia, neuropathy, hypersensitivity reaction, alopecia, mucositis, nail changes and cutaneous reactions such as acral erythema. We describe a unique docetaxel-induced cutaneous reaction presenting as fixed erythematous plaque(s) unrelated to extravasation or previous skin injury; histopathological studies were performed in three of the four cases.

Grandparents in the United States and the Republic of China: a comparison of generations and cultures

Grandparent behaviors in the United States and the Republic of China are examined to identify curriculum themes for helping them adjust to their changing role. The 3,286 non-consanguineous subjects included Chinese (n = 751), African Americans (n = 777), Caucasian Americans (n = 1,086), and Mexican Americans (n = 672). Analyses were performed using 1) Generation with three levels (grandparent, parent, and grandchild) and 2) Culture with four levels (Chinese, African American, Caucasian American, and Mexican American). The results revealed significant differences in perceptions about grandparents across cultures as well as between generations within cultures. All three generations reported grandparent strengths and needs. Specific guidelines and curriculum topics are recommended for education to support grandparent development.

Down's syndrome with mucosa-associated lymphoid tissue, thyroid lymphoma and cerebral infarction

Primary lymphoma of the thyroid gland is rare. The histopathology of most low-grade thyroid lymphomas is of a mucosa-associated lymphoid tissue (MALT) type. A typical feature of this type of lymphoma is a close lymphocyte-epithelium interaction. It tends to appear in patients with a history of autoimmune disease or chronic inflammatory disorders. A clinical picture of hypothyroidism may be present. Hyperthyroidism associated with thyroid lymphoma is also rare. Thyroid lymphoma could be misdiagnosed as lymphocytic thyroiditis or small cell anaplastic carcinoma. It is rarely reported in patients with Down's syndrome. In this report, we describe a Down's syndrome patient with MALT thyroid lymphoma and cerebral infarction. The patient, a 42-year-old man, presented with chest discomfort and bilateral leg weakness of one week's duration. Physical examination of his neck showed a right-sided mass lesion. Neurologic examination revealed decreased muscle power and hyperreflexia in both lower legs. Babinski's sign was present bilaterally. Endocrinologic studies showed subclinical hypothyroidism. A thoracolumbar radiograph showed disc space narrowing. Thyroid sonography revealed a hypoechoic mass lesion in the right lobe of the thyroid gland. Fine needle aspiration cytology of the neck mass demonstrated a large amount of lymphocyte infiltration. An I131 thyroid scan and 24-hour uptake revealed the possibility of thyroid malignancy at the upper poles of both thyroid lobes. Computerized tomography of the brain revealed a lacunar infarct in the posterior aspect of the left putamen. Magnetic resonance imaging of the lumbar spine revealed a healed L4 compression fracture with L4-5 retrolithesis. The patient later underwent a right total thyroidectomy. The pathologic finding showed MALT lymphoma. The patient received steroid suppression therapy, and after nine months of treatment and follow-up, he developed clinical hypothyroidism. Neither local tumor recurrence nor distant metastasis was found.

The normal width of anterior hip synovial recess in children

To establish the diagnostic criteria for hip joint effusion, the normal width of the anterior hip synovial recess in children and the difference between both hips of the same child were examined in this study. Eight kindergarten schools were randomly selected for study in Kaohsiung City. The width of anterior hip synovial recess of 1,568 hips in 784 children (421 boys, 363 girls) was measured by ultrasound scanner with 7.5-MHz linear probe. The age of children ranged from 2.5 to 6.6 years old. During measurement, the children were put in supine position with hips and knees in extension and patella facing up. The results revealed that the mean width of the anterior synovial recess was 7.29+/-1.15 mm. Linear correlation of the width of synovial recess to age and height was disclosed and expressed as follows: width (millimeters) equal to 6.52+0.013x age (months), or width (millimeters) equal to 3.97+0.030x height (centimeters). The mean difference between both hips of the same child was 0.611+/-0.523 mm, and the difference was independent from the factors of age, gender, height, or weight (p>0.05). Ninety-five percent of the differences should be < or =1.46 mm, so that if the difference between hips is >1.46 mm, hip joint effusion should be suspected.

Fluoride in drinking water and cancer mortality in Taiwan

The possibility that cancer risk is associated with naturally fluoridated water in Taiwan is examined. The 1982-1991 age-adjusted mortality rates for cancer for 10 municipalities whose water supplies contained the highest naturally occurring fluoride concentrations in Taiwan were compared to those rates for 10 matched municipalities with unfluoridated water. The two groups had similar urbanization levels and sociodemographic characteristics. Our study does not support the suggestion that fluoridation of water supplies is associated with an increase in cancer mortality in Taiwan.

Measurement of the total cross section for hadronic production by e(+)e(-) annihilation at energies between 2.6-5 GeV

Using the upgraded Beijing Spectrometer, we have measured the total cross section for e(+)e(-) annihilation into hadronic final states at center-of-mass energies of 2.6, 3.2, 3.4, 3.55, 4.6, and 5.0 GeV. Values of R, sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->&mgr;(+)&mgr;(-)), are determined.

HRad17 colocalizes with NHP2L1 in the nucleolus and redistributes after UV irradiation

The rad17 gene of Schizosaccharomyces pombe plays an important role as a checkpoint protein following DNA damage and during DNA replication. The human homologue of S. pombe rad17, Hrad17, was recently identified, but its function has not yet been established. Using the yeast two-hybrid system, we determined that HRad17 can interact with a nucleolar protein, NHP2L1. This interaction was also demonstrated biochemically, in human cells. Immunofluorescence studies revealed that HRad17 and NHP2L1 colocalize to the nucleolus, and immunogold labeling further resolved the location of NHP2L1 to the dense fibrillar component of the nucleolus. Interestingly, the localization of HRad17 in the nucleolus was altered in response to UV irradiation. These results provide some insight into the DNA damage and replication checkpoint mechanisms of HRad17.

[A clinical study on prosthodontic treatment of periodontal problems with conical telescopic removable denture]

OBJECTIVE:Clinical study was made on curative effect of medium to severe periodontal diseases as well as those complicated with partial edentulism by conical telescopic removable denture.METHODS:14 cases of medium to severe periodontal diseases and these complicated with partial edentulism were treated with prosthodontic methods after comprehensive periodontal therapy.Examinations of both before and following prosthetic restoration of 3,12,14 months were made.Bacterial plague index,gingival index,tooth movability and masticatory efficiency were recorded,analysed and compared. RESULTS:Periodontal plague attachment was under effective control through this way,which also eliminated periodontal trauma thus preventing the relapse of periodontal diseases.Further more it can diminish tooth movability and improve masticatory efficiency continuously as time goes on.CONCLUSION:Conical telescopic removable denturs is an effective prosthetic method in treating medium to severe periodontal diseases.

Short-term effect of ozone on the pulmonary function of children in primary school

The objective of this study was to evaluate the short-term effect of ambient air pollution on the pulmonary function of schoolchildren. We sampled 941 children in primary school in three communities in Taiwan (Sanchun, Taihsi, and Linyuan). The nearby stations of the Taiwan air quality monitoring network provided the hourly ambient concentrations of sulfur dioxide, carbon monoxide, ozone, particulate matter < or = to 10 microm in aerodynamic diameter, and nitrogen dioxide. Spirometry was performed once for each sampled child. We also obtained the status of indoor air pollution and chronic respiratory disease history by using a structured questionnaire. Multivariate linear model analysis was used to evaluate pulmonary function effects of each pollutant in addition to determinants of indoor air pollution and meteorologic conditions. We found a significantly negative association of peak O(3) concentration on the day before spirometry with individual forced vital capacity and forced expiratory volume in 1 sec. The decrease in children's lung function can occur at peak hourly O(3) concentrations < 80 ppb. The slope of lung function decrease for Taiwanese children is approximately 1 mL/ppb for peak hourly O(3) exposure.

Anatomical and electrophysiological evidence for GABAergic bipolar cells in tiger salamander retina

Our previous work showed that about 12% of bipolar cells in salamander retina synthesize and take up gamma-aminobutyric acid (GABA), are GABA transporter (GAT)-immunoreactive, and respond with a GAT current to extracellularly applied GABA, suggesting that these bipolar cells use GABA, in addition to glutamate, as a neurotransmitter. Further support for this idea was obtained in this study by use of immunogold electron microscopy and whole-cell patch clamp electrophysiology. Ultrastructural analysis showed that amacrine cell and ganglion cell processes were postsynaptic to GABA-immunoreactive synapses made by bipolar cell axon terminals. Whole-cell recordings were obtained from amacrine and ganglion cells in response to activation of bipolar cells by puffing KCl at their dendrites in the outer plexiform layer. Inhibitory postsynaptic currents were observed in several third order neurons, even after blocking the excitatory postsynaptic responses, generated in the inner plexiform layer, with a combined application of NMDA and non-NMDA receptor antagonists, AP-5 and CNQX. These ultrastructural and electrophysiological data support our previous neurochemical results, and suggest that the retinal through-information pathway in salamander includes both inhibitory GABAergic as well as excitatory glutamatergic synaptic mechanisms.

Esophageal cancer mortality and total hardness levels in Taiwan's drinking water

The possible association between the risk of esophageal cancer and hardness levels in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. All eligible esophageal cancer deaths (2084 cases) of Taiwan residents from 1987 through 1996 were compared with deaths from other causes (2084 controls), and the hardness levels of the drinking water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from the Taiwan Water Supply Corporation (TWSC). The control group consisted of people who died from other causes and the controls were pair-matched to the cases by sex, year of birth, and year of death. The results show that there is a 42% excess risk of mortality from esophageal cancer in relation to the use of soft water (adjusted odds ratio and 95% confidence intervals was 1.42 (1.22-1.66). This is an important finding for the Taiwan water industry and human health.

Synaptic architecture of glomeruli in lamina II of the chicken spinal cord, as revealed using ultrathin section and freeze fracture techniques

Synaptic glomeruli in lamina II of the chicken dorsal horn were studied using the freeze fracture technique, and the results were compared with those obtained using the ultrathin section technique. Our findings using the freeze fracture technique were as follows. (1) On the presynaptic P-face of the central terminal, intramembrane particles (IMPs) were arranged circularly around a small dimple which was reported to be a synaptic vesicle attachment site. A distinct area with aggregated large IMPs was found on the postsynaptic E-face of some peripheral neuronal elements. (2) The area with small IMPs intermingled with several dimples and the area with aggregated large IMPs were present juxtaposed on the same central terminal P-face. The area with aggregated large IMPs indicates that the central terminal functions as a postsynaptic element; accordingly, the two areas represent a reciprocal synapse. (3) Distinct IMP aggregates were observed on the P-face of vesicle-containing dendrites which did not face the central terminal. (4) A fractured septate junction was revealed as numerous parallel-lined furrows on the E-face of the central terminal. The distribution of IMPs in the synaptic glomerulus supports the hypothesis that the synaptic glomerulus is the site of the local inhibitory feedback circuit for pain transmission.

Multiplane transesophageal echocardiography for assessing cardiac abnormalities: comparison to biplane imaging

BACKGROUND

Transesophageal echocardiography (TEE) is useful for visualizing the spatial relationships of the cardiac anatomy. The purpose of this study was to compare the diagnostic yield of multiplane TEE with that of biplane TEE in assessing cardiac abnormalities.

METHODS

A total of 102 consecutive patients underwent an initial comprehensive diagnostic assessment using transverse (0 degree) and longitudinal (90 degrees +/- 2 degrees) planes in the biplane imaging technique. "Off-axis" tomographic sections through the full 0 degree to 180 degrees angle were obtained later by means of the gradual electrical rotation of the transducer. The echoscope can be manipulated to improve the quality of images. All data were recorded on high fidelity videotapes. Subsequently, one observer reviewed only biplane TEE images, while another reviewed only multiplane TEE images; both were blinded to the other's TEE data. The echocardiographic results obtained by these two observers were compared to determine whether multiplane TEE provides any additional information.

RESULTS

Multiplane TEE detected more cardiac lesions (275) compared to biplane TEE (235). Significantly more (70 cases) information affecting patient management was obtained using multiplane TEE. Among these patients, biplane TEE detected cardiac lesions in 48 (68.6%) patients. Additional diagnoses provided by multiplane TEE were found in 22 (31.4%) patients. These findings included ventricular septal defect in two patients, prosthetic valve dysfunction in three, cardiac tumor or clot in four, endocarditis in two, aortic dissection in one, valvular abnormality in nine and coronary arteriovenous fistula in one.

CONCLUSIONS

Multiplane TEE provides precise visualization of cardiac structures without undue probe manipulation, resulting in greater diagnostic assurance than does biplane TEE.

Effect of passivation on the dissolution behavior of Ti6A14V and vacuum-brazed Ti6A14V in Hank's ethylene diamine tetra-acetic acid solution Part I Ion release

This work aims to investigate the effects of three factors, namely: (1) two differently prepared materials (as-polished Ti6A14V and 2 h brazed Ti6A14V); (2) three different surface passivation treatments (34% nitric acid passivation, 400 degrees C heated in air, and aged in 100 degrees C de-ionized water); and (3) periods of immersion time (up to 32 days), on trace element release in Hank's ethylene diamine tetra-acetic acid (EDTA) solution. After passivation and autoclaving treatment, the specimens were immersed in 8.0 mM EDTA in Hank's solution and maintained at 37 degrees C for periods of time up to 32 days. The 400 degrees C -treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the higher thickness and rutile structure of the surface oxides. For acid-passivated and water-aged treatments, a highly significant decrease in the trace levels of Ti, A1, and V is detected from the brazed Ti6A14V compared to those obtained from the Ti6A14V specimens. It is hypothesized that an anatase-rutile transformation of surface TiO_2 is likely to occur, accelerated by the elements of copper and nickel in the brazed specimens. In addition, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-8 day experimental period. The implication of the results is discussed.