Biomedical subjects

R C Wang

Publications and source records attributed to R C Wang.

At least 19 recordsLinked to original sources

PubMed2006

Microbial population structure changes in a suspended carrier biofilm reactor.

The changes of microbial population structure in biofilm caused by variations of COD/NHNH4(+)-N ratio in influent were investigated in a suspended carrier biofilm reactor (SCBR). When COD/NHNH4(+)-N was 10, the highest COD removal reached was about 73.8 per cent, whereas the highest NH4(+)-N removal, about 55.9 per cent, was reached when COD/NH4(+)-N was 5. By using fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) observation, it was found that the thickness of the biofilm formed on the carrier was about 80 to 120 microm, and ammonia-oxidizing bacteria (AOB) and nitrifying bacteria existed mainly in the upper layer about 20 to 30 microm. The results of the quinone profile analysis showed that when the COD/NH4(+)-N increased, the microbial diversity (DQ) increased, while the proportions of AOB and nitrifying bacteria in the biofilm communities decreased.

Ammonia↗

PubMed2005

Microglial stability and repopulation in the retina.

BACKGROUND/AIMS: Parenchymal central nervous system microglia are repopulated by bone marrow derived monocytes more slowly than any other reticuloendothelial cells. The contribution of bone marrow derived monocytes to the uninflammed retina has not been studied. The present study sought to determine repopulation of retinal microglia in uniflammed retina by bone marrow derived monocytes in bone marrow chimeric rats. METHODS: Chimeric (Y-->X) Lewis rats were constructed by transplanting 5 x 10(7) male bone marrow cells into lethally irradiated female recipient rats. The chimeras were sacrificed 8, 10, 12, 30, and 52 weeks after bone marrow transplant, and retina, brain, lung, and spleen samples were collected. DNA was extracted and quantified. Y positive infiltrating cells in the collected samples were detected by polymerase chain reaction amplification of a Y chromosome specific 104 bp fragment. RESULTS: There was a rapid repopulation of haematopoietic tissues in the spleen (at 8 weeks), confirming the establishment of chimerism, and to a lesser extent, of lung (at 30 weeks). This repopulation was absent in the brain parenchyma and retina until 52 weeks after transplantation. CONCLUSIONS: These data indicate that resident microglia in the retina, much like those in the brain, are stable in number in the retinal compartment (up to 1 year), and repopulation by bone marrow derived cells may be delayed for a year.

Animals↗

PubMed2000

Visual loss and central venous catheterization: cortical blindness and hemianopsia after inadvertent subclavian artery entry.

A case of presumed embolic transient ischemic episodes and multifocal infarcts to the occipital and parietal cortices and the cerebellum of a young woman with ulcerative colitis is reported. These episodes were manifested by multifocal neurologic deficits including cortical blindness, visual hallucinations, and homonymous hemianopsia. They correlated with parenteral nutrition via a central line, presumed venous, but found to be in the subclavian artery. The complications of central venous lines are reviewed. The need for attention to neighborhood structures and unexpected symptoms, in view of the less well-recognized arterial embolic complications is emphasized.

Adult↗

PubMed2000

Identification and characterization of wheat-wheatgrass translocation lines and localization of barley yellow dwarf virus resistance.

Stable introgression of agronomically important traits into crop plants through wide crossing often requires the generation and identification of translocation lines. However, the low efficiency of identifying lines containing translocations is a significant limitation in utilizing valuable alien chromatin-derived traits. Selection of putative wheatgrass-wheat translocation lines based on segregation ratios of progeny from gamma-irradiated seed using a standard phenotypic analysis resulted in a low 4% success rate of identifying barley yellow dwarf virus (BYDV) resistant and susceptible translocation lines. However, 58% of the susceptible progeny of this irradiated seed contained a Thinopyrum intermedium chromosome-specific repetitive sequence, which indicated that gamma-irradiation-induced translocations occurred at high rate. Restriction fragment length polymorphism (RFLP) analysis of susceptible lines containing alien chromatin, their resistant sister lines and other resistant lines showed that more than one third of the progeny of gamma-irradiated double monosomic seeds contained wheatgrass-wheat translocations. Genomic in situ hybridization (GISH) analysis of selected lines confirmed that these were wheatgrass-wheat translocation lines. This approach of initially identifying BYDV susceptible deletion lines using an alien chromosome-specific repetitive sequence followed by RFLP analysis of their resistant sister lines efficiently identified resistant translocation lines and localized the BYDV resistance to the distal end of the introgressed Th. intermedium chromosome.

Chromatin↗

PubMed1999

Reduction of adenosine-5'-phosphosulfate instead of 3'-phosphoadenosine-5'-phosphosulfate in cysteine biosynthesis by Rhizobium meliloti and other members of the family Rhizobiaceae.

We have cloned and sequenced three genes from Rhizobium meliloti (Sinorhizobium meliloti) that are involved in sulfate activation for cysteine biosynthesis. Two of the genes display homology to the Escherichia coli cysDN genes, which code for an ATP sulfurylase (EC 2.7.7.4). The third gene has homology to the E. coli cysH gene, a 3'-phosphoadenosine-5'-phosphosulfate (PAPS) reductase (EC 1.8.99.4), but has greater homology to a set of genes found in Arabidopsis thaliana that encode an adenosine-5'-phosphosulfate (APS) reductase. In order to determine the specificity of the R. meliloti reductase, the R. meliloti cysH homolog was histidine tagged and purified, and its specificity was assayed in vitro. Like the A. thaliana reductases, the histidine-tagged R. meliloti cysH gene product appears to favor APS over PAPS as a substrate, with a Km for APS of 3 to 4 microM but a Km for PAPS of >100 microM. In order to determine whether this preference for APS is unique to R. meliloti among members of the family Rhizobiaceae or is more widespread, cell extracts from R. leguminosarum, Rhizobium sp. strain NGR234, Rhizobium fredii (Sinorhizobium fredii), and Agrobacterium tumefaciens were assayed for APS or PAPS reductase activity. Cell extracts from all four species also preferentially reduce APS over PAPS.

Adenosine Phosphosulfate↗

PubMed1998

The tension wire method: a simple, effective means of mandibular fixation.

OBJECTIVE: To investigate the use of a tension wire band secured to monocortical screws for open reduction and internal fixation of simple, displaced, and/or unstable mandibular fractures. DESIGN: Retrospective review with follow-up duration of at least 6 weeks. SETTING: Level I university trauma center. PATIENTS: Twenty-nine patients (27 males and 2 females), aged 7 to 46 years. Ten patients had unilateral fractures (1 patient had 3 separate unilateral fractures) and 19 had bilateral fractures; 34 of 50 fractures were displaced; 19 were open intraorally. The location of fractures and the number (number repaired) were as follows: symphysis or parasymphysis, 13 (10); body, 9 (8); angle, 18 (14); ramus, 6 (4); and subcondylar, 4 (0). Two fractures were each comminuted into 3 fragments, and 1 patient had unilateral parasymphysial, body, and ramus fractures. INTERVENTION: Intermaxillary fixation was done in all patients except 1 child. Intraoral approaches were used exclusively. A pair of monocortical 2.0-mm screws were placed perpendicular to fracture lines, with 24-gauge wire loops passed around the screws and tightened to bring the fracture into reduction and provide stable fixation. A percutaneous trocar system was used to insert screws at the body, angle, and ramus sites. RESULTS: There were no instances of infection, malunion, or malocclusion in the 33 fractures repaired with this technique. A typical intermaxillary fixation with open reduction and internal fixation of a posterior fracture was done in less than 2 hours. CONCLUSION: Open reduction and internal fixation of simple mandibular fractures with tension wire bands around monocortical screws is a simple, quick, and effective technique.

Adolescent↗

PubMed1998

Accuracy of clinical evaluation in pediatric obstructive sleep apnea.

Eighty-two children underwent polysomnography (PSG) for symptoms suggestive of obstructive sleep apnea (OSA). Symptoms reported included snoring, witnessed apneic episodes, daytime somnolence, mouth breathing, and enuresis. Tonsillar size, nasal airway patency, and percentile weight were recorded. OSA was diagnosed on PSG when obstructive events were noted and apnea + hypopnea index was five or more per hour. The overall predictive accuracy of clinical suspicion of OSA was 25 (30%) of 82. Predictive accuracies (as a percentage of those with symptoms/signs who have OSA) and prevalences (as a percentage of those with OSA who have the symptom/sign), respectively, were for moderate snoring 29% (12 of 41), 48%; loud snoring 31% (11 of 35), 44%; witnessed apneas 32% (22 of 69), 88%; enuresis 46% (11 of 24), 44%; 2+ tonsillar size 37% (21 of 57), 84%; 3+ tonsillar size 33% (3 of 9), 12%; 90th percentile weight or greater 26% (7 of 27), 28%; 10th percentile weight or less 33% (5 of 15), 20%. Multiple regression analysis did not reveal a significant association between clinical parameters and the presence of OSA as defined by PSG.

Adolescent↗

PubMed1998

Three-dimensional analysis of cricoarytenoid joint motion.

The normal motion of the cricoarytenoid joint was characterized and analyzed in this study using seven fresh cadaver larynges mounted rigidly in an external fixator apparatus after radiopaque markers were attached to laryngeal landmarks. Fluoroscopic imaging and recording was performed of top, front, and side views while the arytenoid cartilages of each larynx were manipulated through the full range of motion from adduction to abduction. Computer video capture was performed of the recordings and editing of still frames accomplished to generate three-dimensional plots of cricoarytenoid joint motion, which are shown in the manuscript. Selective and varying sequential disconnection of muscular and ligamentous structures to the arytenoid cartilage was achieved to determine their contributions to cricoarytenoid joint motion limitations and stability. The vocalis ligament, cricoarytenoid ligament, and conus elasticus are most important in controlling abduction, whereas the posterior cricoarytenoid muscle and conus elasticus are crucial in limiting adduction. The vocalis ligament prevents posterior displacement of the vocal process, while the cricoarytenoid ligament and a newly described ligament, the posterior capsular ligament, restricts anterior vocal process migration. Another ligament, the anterior capsular ligament, is described, which limits backward arytenoid cartilage tilting and lateral movement of the arytenoid cartilage on the cricoid cartilage facet. Section of the vocalis ligament with underlying conus elasticus produced reducible lateral arytenoid cartilage subluxation. Confirmation of cricoarytenoid joint facet relationships in full adduction and abduction was accomplished by fixation of the cricoarytenoid joints of one larynx in the two positions with adhesive, and subsequent exposure of the joint surfaces. Review of literature detailing human laryngeal embryological development shows that the glottis and arytenoid cartilages are formed in adduction, which explains how cricoarytenoid joint ligaments collaborate to achieve accurate vocal process approximation in adduction despite side-to-side asymmetries of the cricoarytenoid joint structures in the same larynges.

Adult↗

PubMed1998

Strap muscle neurovascular supply.

OBJECTIVES/HYPOTHESIS: Knowledge and preservation of the neurovascular supply to strap muscles, such as the sternohyoid (SH) muscle, used in laryngotracheal reconstruction are important in preventing loss of tissue and bulk from ischemia and/or denervation. STUDY DESIGN: Arteriovenous and neural supply variations to the strap muscles were examined in cadaver specimens. METHODS: Strap muscle neurovascular supply was studied in 16 cadavers, including one transparent corrosion cast specimen with injected vessels. RESULTS: For the upper SH and upper belly of the omohyoid (OMO), the arterial supply consistently arose from a branch of the superior thyroid artery (STA) most commonly terminating at the cricothyroid membrane. The inferior SH was supplied by the inferior thyroid artery. The ansa cervicalis innervated the SH inferiorly with a branch below the loop. Each arterial branch to the muscles had an accompanying venous tributary. The corrosion cast specimen demonstrated that the arterial lumen diameters were almost threefold larger in branches entering the upper SH, compared with the lower SH or OMO. Small intramuscular arteries without axial supply were found within the middle third of the upper SH, the lower SH, and the upper OMO. CONCLUSIONS: It is possible to preserve neurovascular integrity in an inferiorly based SH flap. The superior and medial borders are released, with dissection of vascular supply laterally and deep to the muscle, and preservation of the inferior terminal ansa branch.

Arteries↗

PubMed1997

Frozen section--guided surgical debridement for management of rhino-orbital mucormycosis.

PURPOSE: To present a new method of surgical treatment for rhino-orbital mucormycosis. METHOD: We treated a patient with extensive surgical debridement of mucormycosis with intraoperative frozen section guidance. The patient did not require exenteration. RESULT: Our patient survived with normal vision and no diplopia. CONCLUSIONS: Frozen section-guided surgical debridement in rhino-orbital mucormycosis may provide an alternative to traditional radical surgical excision. In selected cases, this new method of treatment may cause less morbidity than do traditional treatments.

Adult↗

PubMed1995

Alveolar integrity in pulmonary emphysema using technetium-99m-DTPA and technetium-99m-HMPAO radioaerosol inhalation lung scintigraphy.

UNLABELLED: The alveolar integrity (AI) in 17 male patients with pulmonary emphysema (EMPH) diagnosed by chest x-ray was measured by 99mTc-DTPA and 99mTc-HMPAO radioaerosol inhalation lung scintigraphy. METHODS: The patients were divided into two groups: (A) nine patients with pulmonary emphysema and normal carbon monoxide diffusion capacity (DLCO) and (B) eight patients with pulmonary emphysema and abnormal DLCO. The degree of AI damage in EMPH was presented as the slope of the time-activity curves from the dynamic left lung imagings in DTPA and HMPAO. The AI of EMPH patients were compared with the AI of 16 normal controls. RESULTS: The results show that: (1) the slope of DTPA is larger than that of HMPAO in each of the portions of the left lung for any of the study groups; (2) statistical differences were found between the normal controls and EMPH patients in HMPAO but not in DTPA; and (3) the correlation was not good between DLCO and DTPA/HMPAO in EMPH patients. CONCLUSION: Our results suggest that: (1) at least two different mechanisms in the lungs were at work; (2) the AI damage in EMPH developed mainly in the lipophilic part of the alveoli; and (3) the AI damage presented as slopes of DTPA/HMPAO in our study was different from the traditional pulmonary function such as DLCO.

Administration, Inhalation↗

PubMed1993

Transforming growth factor-beta 1 induces transforming growth factor-alpha promoter activity and transforming growth factor-alpha secretion in the human colon adenocarcinoma cell line FET.

FET cells are well differentiated human adenocarcinoma cells whose growth is partially inhibited (50-60%) by transforming growth factor-beta 1 (TGF-beta 1). In exponentially growing cultures, TGF-beta 1 induces the expression of transforming growth factor-alpha (TGF-alpha) by 3-fold. To determine whether this induction is the result of increased TGF-alpha promoter activity, FET cells were transiently transfected with a plasmid containing 2816 base pairs of the 5'-flanking region of the TGF-alpha gene linked to luciferase. Transfected FET cells treated with growth-inhibitory concentrations of TGF-beta 1 (10 ng/ml) showed up to a 10-fold increase in luciferase activity. The increase in luciferase activity was dose dependent through the normal physiological range of TGF-beta 1 (0.5-20 ng/ml), saturating at 10 ng/ml. This effect was also TGF-alpha promoter specific, inasmuch as the Rous sarcoma virus long terminal repeat used as a control remained relatively insensitive to the effects of TGF-beta 1. By using progressively smaller portions of the TGF-alpha promoter region, the TGF-beta 1-responsive element was mapped between base pairs -77 and -201 of the 5'-flanking region. TGF-beta 1 treatment also affected epidermal growth factor receptor levels. FET cells treated with TGF-beta 1 (10 ng/ml) for 48 h showed a 20% decrease in the number of epidermal growth factor receptors and a 2-fold increase in the number of high affinity epidermal growth factor receptors on their surface. These results indicate that TGF-beta 1 acts as a positive regulator of TGF-alpha transcription, and they suggest a possible mechanism by which these cells circumvent the growth-inhibitory effects of TGF-beta 1.

Adenocarcinoma↗

PubMed1993

Penetration of mitomycin C in human bladder.

The penetration of mitomycin C (MMC) in bladder tissue was studied in patients who received intravesical chemotherapy at the time of radical cystectomy. An intravesical dose of MMC (20 mg/40 ml) was instilled and maintained in the bladder for 60 to 120 min at which time the solution was drained. Within 10 to 60 min after draining the drug solution, the bladder vasculature was ligated, and the bladder was removed. Tissues were sectioned serially in layers parallel to the urothelium and analyzed for MMC concentration. Of the 24 patients evaluated, 17 patients had a low final MMC concentration in urine (< 66 micrograms/ml) or had the MMC solution drained more than 30 min before ligation of the blood vessels. Among these 17 patients, the concentration in the urothelium was measurable in only 4 patients, while the concentrations in deeper tissues were not measurable. In the remaining 7 patients where the urine concentration was > 120 micrograms/ml and where the vasculature was ligated within 30 min after the MMC solution was drained, the bladder wall contained significant MMC concentrations. The drug penetration was studied in the latter 7 patients, using sections of bladder wall that were grossly normal and non-tumor bearing. Concentrations in the bladder wall declined semilogarithmically with tissue depth from the urothelium to the deep muscle and reached a plateau at about 2000 microns depth. The median MMC concentrations were 5.6 micrograms/g in the urothelium and lamina propria interface, 2.7 micrograms/g in the lamina propria, and 0.9 microgram/g in the muscularis. The distance over which the MMC concentration decreased by one-half was about 500 microns. The concentration ratio between the urine and urothelium/lamina propria interface was about 35-fold. The mean plasma concentrations were 0.003, 0.1, and 0.4% of the mean concentration in urine, urothelium, and the averaged bladder tissue concentrations, respectively. Paired superficial tumor and normal tissues were obtained from 5 bladders. In 4 of 5 cases, the concentration in tumors was higher than in normal tissues, while the reverse was seen in the remaining tumor. In one sessile bladder tumor a complete concentration-depth profile could be obtained. While the concentrations in the tumor tissue were 2-3-fold higher than that in the adjacent normal tissue, the rate of concentration declined with respect to tissue depth and hence the distance over which the MMC concentration decreased by one-half was similar in both tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Intravesical↗

PubMed1993

Adult supraglottitis.

Airway management of supraglottitis in the adult is controversial as regards the choice between observation and acute intervention. This study was undertaken to determine whether factors exist that place patients at higher risk of airway obstruction and to review conservative treatment outcome. Of 46 cases during an 8-year period, seven required tracheostomy and 39 were observed. Odynophagia and fever were present in all patients. Yearly clusters of up to six cases in 1 month were detected. White blood cell count and heart rate were significantly more elevated in those who underwent tracheostomy. A symptom duration of less than 24 hours was associated (p < 0.05, chi 2 analysis) with airway compromise as well. There was no associated morbidity or mortality, and mean hospital stay was 5.2 days for those observed and 7.9 days for those who underwent tracheostomy.

Adolescent↗

PubMed1993

Fiberglass dermatitis: report of two cases.

Fiberglass is widely used for insulation and as a reinforcement filling material. Handling fiberglass products may induce contact dermatitis. We report on the first two cases of fiberglass dermatitis reported in Taiwan. The first patient suffered from a severe pruritic eruption two hours after repairing a roof with wave-form ceiling boards. Erythematous maculopapules were present on both hands and finger webs. The second patient was a quality controller of printed circuit boards (PRCBs). She presented with erythematous maculopapules on the face and excoriated papules and lichenified plaques on the trunk and forearms, which had been present for two years. Scrapings of the skin lesions from both patients showed fiberglass spicules of 7.5 to 8 microns in diameter. Similar fibers were detected in scrapings from the wave-form ceiling board and PRCB. Histopathology of the second case revealed spongiotic psoriasiform dermatitis. Patch tests in case 2 with the plastics and glues series, epoxy resin and scrapings from the PRCBs were all negative. Fiberglass dermatitis may be easily misdiagnosed. Clinically, it may resemble scabies, eczematous dermatitis, folliculitis, petechiae and urticaria. A high index of suspicion is essential for a correct diagnosis.

Adult↗

PubMed1993

Apical malignancies diagnosed by ultrasound-guided fine needle aspiration biopsy.

Sixteen patients with apical malignancies, including 12 with Pancoast tumors and four with metastatic apical pleural masses, underwent chest ultrasound (US) examinations and direct percutaneous fine needle aspiration biopsy (FNAB). Of those, 15 patients were proven to have malignancies by FNAB and the remaining patient (only revealing necrosis by FNAB) was also proven to have a Pancoast tumor after surgical intervention. Percutaneous FNAB was performed through the supraclavicular approach (n = 10) or through the upper back (n = 6). The sonographic appearances of the apical malignancies were homogeneous hypoechoic (n = 8), homogeneous isoechoic (n = 3) or heterogeneous (n = 5). No complications occurred after the FNAB. Our limited experience showed that a convex probe was convenient and useful in the detection of apical malignancies. Apical malignancies, diagnosed previously by percutaneous needle aspiration under fluoroscopy or surgical intervention, can be easily diagnosed by percutaneous FNAB, especially when the FNAB is performed using the supraclavicular approach.

Aged↗

PubMed1992

Serodiagnosis of tuberculosis by an enzyme-linked immunosorbent assay using mycobacterial antigen 60.

This study was undertaken to assess the diagnostic utility of an enzyme-linked immunosorbent assay using mycobacterial antigen 60 in patients with pulmonary tuberculosis. This test was applied to 210 adults, including 111 patients with active pulmonary tuberculosis, 80 control subjects and 19 patients with inactive pulmonary tuberculosis. Although the serums from the patients with active tuberculosis has a higher mean value of IgG antibody concentration than the control group, there was a considerable overlap of serum IgG antibody level between the two groups. 200 ELISA unit (EU) was established as a reasonable cut-off value, which gave an 80.2% (89/111) sensitivity for the group with active pulmonary tuberculosis and a specificity of 76.3% (61/80) only for the control group. The patients with inactive pulmonary tuberculosis had a positive rate up to 47.4% (9/19) when 200 EU was chosen as a cut-off value.

Adult↗

PubMed1992

Purification and characterization of human macrophage-derived granulomonopoietic enhancing factor (GM-EF).

A granulomonopoietic enhancing factor (GM-EF) capable of promoting the effect of colony-stimulating factors (CSFs) on myeloid progenitor cells has been purified to homogeneity from serum-free medium conditioned by fully mature human macrophages. GM-EF was a glycoprotein with an apparent molecular weight of 74 kd and an isoelectric point of 5.2-5.3. The purified protein was heat stable (75 degrees C for 30 min) and was sensitive to treatment with trypsin, papain, and bacterial protease but not to neuraminidase. The activity of GM-EF could be effectively neutralized by GM-EF-specific antiserum, and no antigenic cross-reactivity was observed using antisera against interleukin (IL)-1, IL-4, and IL-6. These results suggest that GM-EF is a unique cytokine that is different biochemically and antigenically from other hematopoietic enhancing factors such as IL-1, IL-4, and IL-6.

Epitopes↗