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Biomedical subjects

C C Chu

Publications and source records attributed to C C Chu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Duodenojejunal intussusception secondary to hamartomatous polyps of duodenum surrounding the ampulla of Vater.

Duodenojejunal intussusception is a rare pediatric emergency. A case of duodenojejunal intussusception secondary to hamartomatous polyps of the second portion of duodenum in a 10-month-old boy is reported. Surgical excision of the polyps and reduction of the intussusception were performed. Pathologic examination found hamartomatous polyps. This is the third case report of children in literature, but this is the first case of a child with intussusception surrounding the ampulla of Vater and a successful excision performed without damaging the ampulla of Vater.

Ampulla of Vater↗
PubMed2001

Carbon disulfide vasculopathy: a small vessel disease.

We present the clinical manifestations of 4 male patients with acute stroke-like symptoms and polyneuropathy after long-term exposure to carbon disulfide (CS2) in a viscose rayon plant. The ages of onset of polyneuropathy ranged from 42 to 45 years with a duration of CS2 exposure between 6 and 21 years. The ages of onset of stroke were from 42 to 48 years. The risk factors for stroke including heart disease and diabetes were denied, except for smoking in 4, hyperlipidemia in 2 and hypertension in 1. At the initial visit in 1992, only 2 patients developed sudden onset of hemiparesis suggesting a lacunar stroke before the diagnosis of CS2 intoxication. Brain computed tomography (CT) scans showed low-density lesions in the basal ganglia in 2 patients, cortical atrophy in 1 and normal in 1. Brain magnetic resonance image (MRI) study disclosed multiple lesions in the corona radiata and basal ganglia on T(2)-weighted images in 3 patients and cortical atrophy in 1. After the diagnosis, they left their jobs for a CS2-free environment, and improvement of the working conditions was noted. During 5 years follow-up period, another 2 patients also developed an acute episode of stroke with hemiparesis. Brain CT and/or MRI follow-up studies in these 2 patients revealed new lesions in the basal ganglia and corona radiata. Intriguingly, a patient with previous stroke also developed new lesions in the bilateral thalami and brainstem. Carotid Doppler scan, transcranial Doppler scan and/or cerebral angiography did not show any prominent stenosis or occlusion in the major intracranial large arteries. We conclude that encephalopathy may occur in patients after long-term CS2 exposure, probably due to impaired cerebral perfusion. The lesions tend to occur in the basal ganglia, corona radiata and even brainstem, particularly involving the small-sized vessels. In addition, the cerebral lesions may progress even after cessation of CS2 exposure. Therefore, we suggest that CS2 exposure may be a risk factor for stroke.

Adult↗
PubMed2001

Efficacy of CC traps and seasonal activity of adult Bemisia argentifolii (Homoptera: Aleyrodidae) in Imperial and Palo Verde Valleys, California.

Adult whitefly Bemisia argentifolii Bellows & Perring trap (CC trap) catches were compared with suction type trap catches. CC trap catches were significantly correlated to the suction trap catches. Higher numbers of B. argentifolii adults were caught in CC traps oriented toward an untreated, B. argentifolii-infested, cotton field as compared with traps oriented toward Bermuda grass fields, farm roads, or fallow areas. CC trap catches at five heights above ground (from 0 to 120 cm) were significantly related to each other in choice and no-choice studies. CC trap catches were low in the Imperial and Palo Verde Valleys from late October to early June each of 1996, 1997, and 1998. Trap catches increased with increasing seasonal air temperatures and host availability. Trap catches were adversely affected by wind and rain. Abrupt trap catch increases of 40- to 50-fold for 1-2 d in late June to early July followed by abrupt decreases in adult catches suggest migrating activity of adults from other nearby crop sources.

Animals↗
PubMed2001

[Improvement of transformation frequency of rice mediated by Agrobacterium].

The factors influencing the frequency of rice transformation mediated by Agrobacterium have been investigated by using 16 commercially important indica and japonica rice cultivars or lines. The main results were as following: For most rice CC medium was the best for both callus initiation and subculture. With supplement of 2.5-5 mg/L ABA the quality of calli can be improved. The concentration of selective agent for Indica rice callus was lower than that for japonica rice callus. Agrobacterium tumefaciens strain EHA105 was more efficient than LBA4404 and AGL1 for rice transformation. The inhibitive effect of cefotaxime to Agrobacterium was better than that of carbenicillin. The partial desiccation treatment after co-cultivation was beneficial to inhibit the growth of Agrobacterium and increase transformation efficiency. A stable and efficient Agrobacterium-mediated transformation system has been established in ten different rice cultivars and fertile transgenic plants have been obtained.

Culture Media↗
PubMed2001

Repeated attacks of venous air embolism during craniotomy--a case report.

Venous air embolism (VAE) is not uncommon during craniotomy, but repeated attacks of VAE during a single surgical procedure is rarely seen. We report a successful intraoperative management of repeated attacks of air embolism in a patient who sustained craniotomy for intracranial hemorrhage (ICH) in prone position. A 70-year-old male suffering from hemorrhage in the right cerebellar hemisphere with impending brainstem herniation was scheduled for craniotomy. He had history of hypertension but it was not well controlled with medical treatment. Emergent craniotomy for removal of blood clot resulting from ICH was performed. During the operation, sudden decrease of end-tidal CO2 (EtCO2) level, fall of blood pressure and increase of central venous pressure (CVP) were noted. Since air bubbles were retrieved from CVP catheter venous air embolism was highly suspected. With prompt diagnosis and proper management, we successfully improved the patient's hemodynamic status and he was discharged without any sequelae. Early detection together with aggressive treatment is the only way in the management of intraoperative venous air embolism.

Aged↗
PubMed2001

Ventilator-associated pneumonia with circuit changes every 2 days versus every week.

BACKGROUND: Frequent ventilator circuit changes are expensive and sometimes unnecessary. Following the worldwide trend to lengthen the intervals for ventilator circuit change from 2 days to 1 week, this study aims to assure that low rate of ventilator-associated pneumonia (VAP) can be maintained with cost containment. METHODS: Ventilator circuits were routinely changed every 7 days in the study period for 2 years and every 2 days during the historical control period of another 2 years. Pediatric patients (age less than 15 years) were not included. Nosocomial pneumonia was diagnosed by the criteria of the Centers of Disease Control and Prevention (CDC) of the United States (US). VAP was identified by combining and comparing 2 databases from the Respiratory Therapy Department and the Infection Control Unit of our hospital. RESULTS: In the study group, 225 episodes of pneumonias were observed in 7,068 patients and 87,338 ventilator days. The rate of VAP was 2.58 per 1,000 ventilator days. There were 174 episodes of pneumonia in 6,213 patients and 65,467 ventilator days of the control group. The rate of VAP was 2.66 per 1,000 ventilator days. The difference between both groups was not significant (p = 0.803). Yet, the cost curbed was around 80,000 US dollars per year. CONCLUSIONS: Extending ventilator circuit change interval from 2 days to 7 days do not increase the risk for VAP, but the cost savings for labor and supply are substantial.

Adult↗
PubMed2001

[The factors of improving rice transformation efficiency].

The factors influencing the rice transformation frequency have been investigated by using 8 indica and japonica rice cultivars during the transformation procedures, such as induction of calli, selection, and regeneration. The following is the results: The immature embryos were pretreated in 4 degrees C for 4 or 7 days before inoculation, and the regeneration frequency of calli would be increased. High osmotic treatment may increase the possibility of transformation, especially for calli of 6 months or older. The transformation frequency was improved when selection pressure was removed during differentiation period. The V-type selection may be better than the normal selection. There is a difference of differentiation ability among the calli of three periods and it is found that the calli of two or three months are the best for transformation. Proline and DMSO can decrease browning rate of calli.

Dimethyl Sulfoxide↗
PubMed2000

Synthesis and characterization of dextran-methacrylate hydrogels and structural study by SEM.

The objectives of this study were to develop a simple and reproducible method for the preparation of the hydrogel precursor dextran-methacrylate and to conduct a visual observation of the interior structure of the swollen dextran-methacrylate hydrogel with minimum artifacts. A dextran-methacrylate hydrogel precursor was synthesized by reacting dextran with methacrylic anhydride in the presence of triethylamine as a catalyst. The effects of reaction time, temperature, concentration, and catalyst amount were studied to obtain a wide range of degree of substitution (DS) in dextran by methacrylate. The dextran-methacrylate synthesized showed an enhanced solubility in water and common organic solvents. UV irradiation of dextran-methacrylate by a long-wave UV lamp (365 nm) generated a photocrosslinked hydrogel. This dextran-methacrylate hydrogel showed a range of swelling ratio from 67 to 227% and exhibited an increase in swelling ratio with a decrease in methacrylate substitution. The pH of the swelling media did not affect the swelling behavior of the dextran-methacrylate hydrogels at all the degrees of substitution used. Special cryofixation and cryofracturing techniques were used to prepare aqueous swollen dextran-methacrylate hydrogel samples for SEM observation of their surface and interior structures. A unique three-dimensional porous structure was observed in the swollen hydrogel but was absent in the unswollen hydrogel. Different pore sizes and morphologies between the surface and the interior of swollen hydrogels also were observed.

Biocompatible Materials↗
PubMed2000

Pore structure analysis of swollen dextran-methacrylate hydrogels by SEM and mercury intrusion porosimetry.

The objectives of this study were to visually examine the surface and interior morphology of a new class of biodegradable hydrogels based on dextran-methacrylate and to quantify the porous structure of these hydrogels in swollen state. Two techniques (scanning electron microscopy and mercury intrusion porosimetry) were used to analyze pore structure of dextran-methacrylate hydrogels as a function of the degree of methacrylate substitution. SEM was used to observe 3-dimensional network structure of cryofixed and fractured swollen dextran-methacrylate hydrogels. Image analysis of the SEM data revealed different pore shapes and sizes, depending on the degree of substitution and the location within the hydrogel. A higher methacrylate-substituted dextran hydrogel showed a compact and rigid pore structure, while a lower substituted hydrogel showed a delicate and fragile pore structure. Mercury intrusion porosimetry analysis of the pore structure of dextran-methacrylate hydrogels provided useful and more reliable quantitative data of pore characteristics, such as total pore area, average pore diameter, their distribution, and bulk density. The total pore area and average pore diameter of swollen dextran-methacrylate hydrogels decreased with an increase in degree of methacrylate substitution, while bulk density increased with an increase in degree of substitution.

Biocompatible Materials↗
PubMed2000

The role of superoxide ions in the degradation of synthetic absorbable sutures.

The objective of this study was to examine the effect of superoxide ion-induced degradation on synthetic absorbable biomaterials. Synthetic absorbable sutures were used as the model compounds. Inflammatory cells, particularly leukocytes and macrophages, are able to produce highly reactive oxygen species, such as superoxide (. O(2)(-)), during inflammatory reactions to foreign materials. Superoxide ions may act as oxygen nucleophile agents to attack biomaterials. In this study, the changes in tensile breaking force, thermal properties, and the surface morphology of five commercial (2/0 in size) synthetic absorbable sutures (Dexon, Vicryl, PDS II, Maxon, and Monocryl) as a function of superoxide ion concentration at 25 degrees C for 24 h were studied. Among the five absorbable sutures and over the concentration range of this study, the monofilament Monocryl suture was the most sensitive toward superoxide ion-induced degradation, followed by Maxon, Vicryl, Dexon, and PDS II sutures. The amount of tensile breaking force loss over a 24 h period ranged from as low as 3% to as high as 80%, depending on the type of absorbable sutures, the reaction time, and the superoxide ion concentration. All five absorbable sutures showed significant reductions in both the T(m) and T(g). Unlike the surface morphological changes of absorbable sutures in conventional buffer solutions, the effect of superoxide ion-induced degradation on the surface morphologies of these five absorbable sutures was unique, particularly the moon-crater-shaped impressions of various sizes and depths found in Monocryl and Maxon sutures, which defied the anisotropic characteristics of fibers.

Absorption↗
PubMed2000

Transverse testicular ectopia: preoperative diagnosis by ultrasonography.

Transverse testicular ectopia (TTE) is a rare anomaly. We report the first case of TTE described in Taiwan. The physical examination, ultrasonography (US), and laparoscopy revealed both testes in the left hemiscrotum, and surgical correction was performed. This case was diagnosed preoperatively by US, which can offer an easy, safe, and convenient alternative in the preoperative diagnosis of TTE. The possible mechanism for this anomaly and the literature are reviewed.

Cryptorchidism↗
PubMed2000

The study of fine and coarse particles, and metallic elements for the daytime and night-time in a suburban area of central Taiwan, Taichung.

Daily average concentrations of fine and coarse particulates, and TSP samples have been measured simultaneously at daytime and night-time periods by using Universal and PS-1 sampler in a suburban area of central Taiwan from June to August 1998. The samples were analyzed by atomic absorption spectrometry to determine the fine and coarse particulate concentrations of metallic elements (Ca, Fe, Mn, Pb, Cu, Zn and Cr). The concentration of PM2.5 and TSP showed a decreased trend for the daytime period. The fine particle concentrations were about two times as that of coarse particulate concentrations. The averaged fine particulate concentrations at daytime are higher than at night-time. Ca and Fe were mostly in the coarse particulate mode. The correlation coefficients were 0.63 and 0.69 for elements Ca and Fe in the coarse particle mode for day and night periods. Pb showed a similar distribution ratio with Mn for the fine to coarse particle ratios at both day and night period. Pb and Mn are highly correlated for the day (R = 0.78) and night period (R = 0.61) at particle size <2.5 microm. Cu and Zn were mainly in fine particles at both day and night period. Fe and Ca consist of the major parts of all the elements. Elemental Mn is the lowest among the rest of the heavy metals.

Air Pollutants↗
PubMed2000

Heterogeneity of Taiwan's indigenous population: possible relation to prehistoric Mongoloid dispersals.

Taiwan's 9 indigenous tribes (Tsou, Bunun, Paiwan, Rukai, Atayal, Saisiat, Ami, Puyuma, Yami) are highly homogeneous within each tribe, but diversified among the different tribes due to long-term isolation, most probably since Taiwan became an island about 12,000 years ago. Homogeneity of each tribe is evidenced by many HLA-A,B,C alleles having the world's highest ever reported frequencies, e.g. A24 (86.3%), A26 (18.8%), Cw10 (36.8%), Cw7 (66%), Cw8 (32.1%), B13 (27.9%), B62 (37.4%), B75 (18%), B39 (53.5%), B60 (33.3%), and B48 (24%). Also, all of these tribes have HLA class I haplotype frequencies greater than 10%, with A24-Cw7-B39 in Saisiat (44.5%) being the highest, suggesting Taiwan's indigenous tribes are probably the most homogeneous ( the "purest") population in the world. A24-Cw8-B48, A24-Cw10-B60 and A24-Cw9-B61 found common to many Taiwan indigenous tribes, have also been observed in Maori, Papua New Guinea Highlanders, Orochons, Mongolians, Inuit, Japanese, Man, Buryat, Yakut, Tlingit, Tibetans and Thais. These findings suggest Taiwan's indigenous groups are more or less genetically related to both northern and southern Asians. Principal component analysis and the phylogenetic tree (using the neighbor-joining method) showed close relationship between the indigenous groups and Oceanians. This relationship supports the hypothesis that Taiwan was probably on the route of prehistoric Mongoloid dispersals that most likely took place along the coastal lowland of the Asian continent (which is under the sea today). Cultural anthropology also suggests a relationship between Taiwan's indigenous tribes and southern Asians and to a lesser extent, northern Asians. However, the indigenous groups show little genetic relationship to current southern and northern Han Chinese.

Alleles↗
PubMed2000

Orbitofrontal cortex pathology in Alzheimer's disease.

The orbitofrontal cortex has been examined in Alzheimer's disease (AD) from the viewpoint of neurofibrillary tangle (NFT) pathology, its laminar distribution and topography. NFT pathology in the orbitofrontal cortex is extensive in AD. In cases with extensive cortical pathology, NFTs extend from the pole of the frontal lobe to the orbitoinsular junction. In lesser affected cases, the anterior granular part of the orbital cortex is less invested by NFTs. Layers III and V contain the greatest density of NFTs and these are most dense in the dysgranular areas, posterior to the transverse orbital sulcus. Posterior and medial orbitofrontal areas, forming area 13 and the posterior tip of the paraolfactory gyrus, are the most severely damaged, as are the smaller agranular fields that surround the olfactory tract and cortex. The widespread orbitofrontal damage in AD affecting projection neurons suggests that this pathology may contribute heavily to the many non-memory-related behavior changes observed in this disorder.

Aged↗
PubMed2000

In vitro release behavior of dextran-methacrylate hydrogels using doxorubicin and other model compounds.

In vitro drug release behavior of doxorubicin, Alizarin Red S, FITC-dextran from photocross-linked dextran-methacrylate hydrogel was studied. The effects of pH of media, degree of substitution (DS) of dextran-methacrylate hydrogel, and molecular weight of model compounds on their release profiles were investigated. Each model compound was successfully incorporated into dextran-methacrylate hydrogel matrix through photopolymerization of the hydrogel precursor. Delayed release of model compounds was observed with these hydrogels having a higher DS. Doxorubicin and Alizarin Red S showed pH-dependent release behavior because of the presence of ionizable groups in their structure. Different types of ionization of doxorubicin and Alizarin Red S resulted in more release into an acidic or alkaline media. As molecular weights of drugs increased, the total amount of released drug at the end of 240 hrs decreased significantly and reached a minimum level as the MW of drugs reached about 10,000. Release of these three model compounds followed simple Fickian diffusion at an early stage of release, i.e., cumulative release of model compounds was proportional to the square root of time. Dextran-methacrylate hydrogel effectively delayed and controlled the release of anticancer antibiotics, doxorubicin.

Acids↗
PubMed2000

Molecular cytogenetic analysis of intergeneric chromosomal translocations between wheat (Triticum aestivum L.) and Dasypyrum villosum arising from tissue culture.

Fluorescence in situ hybridization (FISH) was applied with total genomic DNA extracted from Dasypyrum villosum (L.) Candargy as a probe to characterize chromosome translocations arising from tissue culture in hybrids of Triticum aestivum x (T. durum - D. villosum, amphiploid). Chromosome translocations between wheat and D. villosum occurred in callus cells at an average frequency of 1.9%. Translocations existed not only in callus cells but also in regenerants. Three plants with translocation chromosomes were characterized among 66 regenerants of T. aestivum 'Chinese Spring' x 'TH1W' and 'NPFP' x 'TH1'. One of them proved to be a reciprocal translocation with an exchange of about one third of a wheat chromosome arm with about one half of a chromosome arm of D. villosum. The breakpoints of the other two translocations were located at, or near centromeres. The results are similar for both callus cells and regenerants and provide further evidence that translocations take place in tissue culture. Other structural chromosomal changes, for example, fragments, telocentrics, dicentromeres, and deletions, as well as numerical alterations including aneuploidy and polyploidy were recorded both in callus cells and regenerants.

Animals↗
PubMed2000

Use of CC traps with different trap base colors for silverleaf whiteflies (Homoptera: Aleyrodidae), thrips (Thysanoptera: Thripidae), and leafhoppers (Homoptera: Cicadellidae).

During 1996, 1997, and 1999, studies were conducted in cotton, sugar beets, alfalfa, yardlong bean, and peanut fields to compare insect catches in CC traps equipped with different trap base colors. The studies were conducted in southwestern United States, China, and India. The nine colors, white, rum, red, yellow, lime green, spring green, woodland green (dark green), true blue, and black, varied in spectral reflectance in the visible (400-700 nm) and near-infrared (700-1050 nm) portions of spectrum. Lime green, yellow, and spring green were the three most attractive trap base colors for silverleaf whitefly, Bemisia argentifolii Bellows & Perring, and leafhopper, Empoasca spp. adults. The three trap base colors were moderately high in the green, yellow, and orange spectral regions (490-600 nm), resembling the spectral reflectance curve of the abaxial (underleaf) surfaces of green cotton leaves. True blue and white were the most attractive trap base colors for western flower thrips, Frankliniella occidentalis (Pergande), adults. The true blue and white trap bases were moderately high in the blue spectral region (400-480 nm).

Animals↗