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G C Yang

Publications and source records attributed to G C Yang.

At least 19 recordsLinked to original sources
PubMed2001

Remediation of TCE contaminated soils by in situ EK-Fenton process.

The treatment performance and cost analysis of in situ electrokinetic (EK)-Fenton process for oxidation of trichloroethylene (TCE) in soils were evaluated in this work. In all experiments, an electric gradient of 1V/cm, de-ionized water as the cathode reservoir fluid and a treatment time of 10 days were employed. Treatment efficiencies of TCE were evaluated in terms of the electrode material, soil type, catalyst type, and catalyst dosage and granular size if applicable. Test results show that graphite electrodes are superior to stainless steel electrodes. It was found that the soil with a higher content of organic matter would result in a lower treatment efficiency (e.g. a sandy loam is less efficient than a loamy sand). Experimental results show that the type of catalyst and its dosage would markedly affect the reaction mechanisms (i.e. "destruction" and "removal") and the treatment efficiency. Aside from FeSO4, scrap iron powder (SIP) in the form of a permeable reactive wall was also found to be an effective catalyst for Fenton reaction to oxidize TCE. In general, the smaller the granular size of SIP, the lower the overall treatment efficiency and the greater the destruction efficiency. When a greater quantity of SIP was used, a decrease of the overall treatment efficiency and an increase of percent destruction of TCE were found. Experimental results have shown that the quantity of electro-osmotic (EO) flow decreased as the quantity of SIP increased. It has been verified that the treatment performances are closely related to the corresponding EO permeability. Results of the cost analysis have indicated that the EK-Fenton process employed in this work is very cost-effective with respect to TCE destruction.

Chromatography, Gas↗
PubMed2001

PNET-like features of synovial sarcoma of the lung: a pitfall in the cytologic diagnosis of soft-tissue tumors.

Fine-needle aspiration (FNA) cytology of soft-tissue tumors is evolving. As more experience is gained, we are becoming aware of potential pitfalls. We describe 2 cases of synovial sarcoma of the lung, primary and metastatic, in patients who had FNA biopsy performed on a lung mass. The cytologic smears showed extremely cellular groups of malignant small round cells, intersected by small blood vessels, with numerous loose single cells, in a background of macrophages and mature lymphocytes. The tumors displayed monomorphic cells forming rosettes and displaying occasional mitoses. A diagnosis of neuroendocrine tumor/primitive neuroepithelial tumor (PNET) was suspected. Furthermore, this suspicion was supported by immunohistochemical stains, which showed positivity for a neuroendocrine marker, Leu 7 (case 1), and for a neural marker, CD 99 (O 13 or HBA 71) (both cases); and negativity for cytokeratins (case 1). The resection specimen of case 1 had mostly tightly packed small round cells, with occasional rosettes, similar to the FNA biopsy, and focal areas composed of spindle cells, organized in a focal fibrosarcoma-like and hemangiopericytoma-like pattern. A balanced translocation between chromosomes X and 18, demonstrated by both karyotyping and fluorescent in situ hybridization (FISH), enabled us to make a diagnosis of synovial sarcoma, which was histologically classified as poorly differentiated. Case 2 was a metastatic biphasic synovial sarcoma of the arm, with a prominent epithelial component. Synovial sarcoma, when composed mainly of small round cells on cytologic smears, is a great mimicker of neuroendocrine/PNET tumors, with light microscopic and immunohistochemical overlap. Awareness of this potential pitfall may aid in preventing a misdiagnosis. Its recognition is of major concern, especially for the poorly differentiated variant, because it is associated with a worse prognosis.

Adult↗
PubMed2001

Ultrasound-guided fine-needle aspiration of the thyroid assessed by Ultrafast Papanicolaou stain: data from 1135 biopsies with a two- to six-year follow-up.

One of the limitations of fine-needle aspiration (FNA) of the thyroid is difficulty in distinguishing the follicular variant (FV) of papillary thyroid carcinomas (PTC) from follicular neoplasms. By highlighting the "Orphan Annie-eyed" clear nuclei of the former, the Ultrafast Papanicolaou stain (UFP) easily separates these two entities. One thousand one hundred thirty-five ultrasound-guided FNAs of the thyroid were assessed by UFP with immediate biopsy results reported to the patients in a busy radiology office in Manhattan from November 1994 to December 1998. Of the 77 thyroid cancers resected, 22 were FVPTC and 17 were microcarcinomas (1 medullary carcinoma, 16 PTC). The rates of "unsatisfactory," "cancer," "suspicious for cancer," "follicular neoplasm," and "benign" cytology were 0.7%, 4.4%, 2.6%, 10.2%, and 82.1%, respectively and the cancer yields at surgery were 98%, 81.8%, 15.8%, and 0% respectively. Of the 1127 satisfactory FNAs in the series with a 2- to -6 years of clinical follow-up, a false-negative rate of 0% and a false-positive rate of 1.5% were obtained. Of the 169 surgical follow-ups with satisfactory FNAs, a sensitivity of 100%, specificity of 66.7%, positive predictive value of 87.4%, negative predictive value of 100%, and global accuracy of 89.9% were achieved. The paradoxical combination of low unsatisfactory rate and low false-negative rate is attributed to (1) the use of needle puncture without syringe to obtain enough microfollicles from the exceedingly bloody aspirates from follicular neoplasms for a diagnosis, (2) eliciting history of neck trauma to confirm hematomas, (3) using UFP to highlight the grape-like watery clear nuclei of FVPTC evident with a 4x objective, and (4) the precise guidance by ultrasound in sampling microcarcinomas.

Adenocarcinoma, Follicular↗
PubMed2001

Endometrial brush biopsy for the diagnosis of endometrial cancer.

OBJECTIVE: To evaluate a new technique for processing endometrial cytology for the diagnosis and exclusion of endometrial cancer. STUDY DESIGN: All women at risk for endometrial cancer with clinical indications for endometrial biopsy were evaluated by endometrial brush biopsy (Tao Brush, Cook OB-GYN, Bloomington, Indiana) and Pipelle (Cooper Surgical, Shelton, Connecticut) endometrial biopsies during one office visit. Patients were followed longitudinally for the development of endometrial cancer or until undergoing dilatation and curettage or hysterectomy. All comparisons were analyzed using the chi 2 or t test. RESULTS: One hundred one women (mean age, 58; range, 35-86) had endometrial biopsies performed. Median follow-up was > 21 months (range, 3-29). Twenty-two had cancer or atypia, while the remaining had benign diagnoses. When correlated with the final diagnosis, the Tao Brush had 95.5% sensitivity and the Pipelle, 86% sensitivity. Both devices had 100% specificity, positive predictive value of 100% and negative predictive value of 98%. When the results of the two biopsy devices are considered together, the positive and negative predictive value for detecting or excluding endometrial cancer was 100%. Based on 1998 Medicare reimbursements, a simultaneous second office biopsy using the Tao brush could save approximately $67 per case as compared to a sonohistogram and much more when compared to dilatation and curettage. CONCLUSION: Endometrial cancer can be reliably detected and excluded using these two distinct office biopsy devices simultaneously during one office visit. In patients with an indication for endometrial biopsy, no further diagnostic test may be necessary to exclude or diagnose endometrial cancer or atypia.

Adult↗
PubMed2000

Fine-needle aspiration cytology of Schiller-Duval bodies of yolk-sac tumor.

The objective of this study was to find the cytological equivalent of Schiller-Duval bodies seen in histology in order to employ the findings as a diagnostic clue for yolk-sac tumor (YST) in aspiration biopsy. A YST, aspirated from the retroperitoneal lymph node of a 29-yr-old Asian man with testicular complex mature teratoma, contained numerous Schiller-Duval bodies on cell block sections. In the corresponding smears, a network of tumor cell-coated, anastomosing, thin-walled, rigid hematopoietic channels with dramatic changes in diameter was observed, in agreement with the diagram based on the reconstruction of 48 serial plastic sections done by Kazancigil et al. (Am J Cancer 1940;40:199-212). In addition, some of the hematopoietic channels folded over several times like a long, narrow balloon pinched at its joints, i.e., "balloon animal"-like. Many segments of the allantoic viteline vascular network, fractured by smearing, exhibited three- or four-way branchings, bulbous protrusions, and cauliflower-like branchings of widely variable diameter.

Adult↗
PubMed2000

Airway cross section strongly influences alveolar plateau slope of capnograms for smaller tidal volumes.

We compared the predictions of the single path convection-diffusion model (SPM) and the well-mixed single acinus model (SAM) with the normalized slopes (NS) of experimentally measured volumetric capnograms in which VT was varied in three healthy spontaneously breathing adults. For values of VT greater than 15 ml/kg, the tidal volume penetrates deep into the acinar airways, mixing by molecular diffusion is rapid and the predictions of the SAM and SPM both agree with the experiment. The SPM however shows much better agreement with the experimental NS data than does the SAM for values of VT less than 10 ml/kg. The explanation for the departure of the SAM from the observed experimental data, at small VT, is that it represents the limiting case (of well-mixed alveolar gas) for the SPM, only at large VT, where the assumption of rapid mixing is most accurate. We conclude that in general, gas phase diffusivity and total acinar airway cross sectional area variation with cumulative volume into the lung are essential to realistically model airway gas exchange between VT and FRC and to obtain agreement with experimental data under the widest range of breathing conditions.

Adult↗
PubMed2000

Endometrial biopsy using the Tao Brush method. A study of 50 women in a general gynecologic practice.

OBJECTIVE: To test whether the Tao Brush can retrieve sufficient endometrium for diagnosis and also to observe patients' tolerance of its use. STUDY DESIGN: Fifty women underwent Tao Brush sampling: 25 were sampled by Tao Brush alone, and the remainder were sampled by Pipelle immediately following. Patients' reactions to each method were observed. RESULTS: Pipelle currettes larger pieces of endometrium; the Tao Brush obtains smaller pieces. There was no discrepancy between Tao Brush and Pipelle except that Pipelle sampled two of five endometrial polyps, while the Tao Brush sampled none. There was less tissue insufficient for diagnosis with the Tao Brush (2%) than Pipelle (12%). Most patients did not show signs of distress during Tao Brush sampling but grimaced during Pipelle suction curettage. For each of the 16 patients in the second group, the Tao Brush was significantly less painful than Pipelle (P < .01). CONCLUSION: Our data suggest that the Tao Brush is an effective alternative endometrial sampler, causes less pain and produces less tissue insufficient for diagnosis than does the Pipelle. The CPT billing codes (58100) are the same for both the Pipelle and Tao Brush.

Adult↗
PubMed1999

Removal and degradation of phenol in a saturated flow by in-situ electrokinetic remediation and Fenton-like process.

In this laboratory study, a sandy loam soil saturated with phenol solution was treated by in-situ electrokinetics-Fenton process incorporated with a permeable reactive wall of scrap iron powder (SIP). The soil was contaminated and saturated with aqueous phenol solution of 90-115 mg/kg in concentration. It was then placed in a soil cell. The soil cell was assembled with an anode reservoir and a cathode reservoir at its ends. A bed of SIP (1.05-32.69 g) was inserted in the soil cell at a distance of 5 cm from the anode reservoir compartment. For the test runs, 0.3% H(2)O(2) was used as the anode reservoir fluid, whereas de-ionized water was used as the cathode reservoir fluid. An electric gradient of 1 V/cm was applied to enhance the saturated flow in the soil cell for a period of 10 days. Experimental results have shown that the electroosmotic (EO) flow quantity decreased as the amount of SIP increased. This phenomenon was in good agreement with the results showing the value of EO permeability increased with a decreasing amount of SIP. Results also showed that throughout the test period the cumulative, consumed mass of H(2)O(2) in the anode reservoir increased as the amount of SIP decreased. On the other hand, the cumulative, increased mass of phenol in the cathode reservoir was found to increase with a decreasing amount of SIP. Meanwhile, the residual phenol concentration in the soil cell was found to decrease with a decreasing amount of SIP. When 1.05 g scrap iron powder was used, an overall removal and destruction efficiency of phenol of 99.7% was obtained. Therefore, it is evident that an in-situ combined technology of electrokinetic remediation and Fenton-like process is capable of simultaneously removing and degrading the phenol in a saturated flow.

Electric Stimulation↗
PubMed1999

Fine-needle aspiration cytology of malignant fibrothecoma of the ovary.

Fibrothecomas are common, but their malignant counterpart is extraordinarily rare. To the best of our knowledge, this is the first report on the cytologic features of malignant fibrothecoma. We had an opportunity to study it because the 70-yr-old woman refused initial surgery until the tumor reached 22 cm in size and weighed 1, 500 gm. A CT-guided fine-needle aspiration biopsy was obtained from a 5 cm left pelvic mass, which was the second recurrence within 5 yr. The smears showed large fragments of tightly packed, small, oval cells with scanty, eccentric blue cytoplasm (Diff-Quik stain), and finely granular chromatin with small central nucleoli (Ultrafast Papanicolaou stain), transected by delicate blood vessels. The tumor resembled well-differentiated carcinoma, low-grade endometrial stromal sarcoma, and other small oval cell gynecologic neoplasms. Cytodiagnosis of nonepithelial ovarian neoplasms can be difficult. However, it is not impossible, especially for recurrent tumors with previously established histodiagnosis. Diagn. Cytopath. 21:284-286, 1999.

Aged↗
PubMed1999

Lipid-rich follicular carcinoma of the thyroid in a patient with McCune-Albright syndrome.

A 41-year-old woman with McCune-Albright syndrome and a 2-cm thyroid nodule of ten years' duration presented for fine-needle aspiration, which yielded vacuolated clear cells with granular chromatin in pseudopapillary arrangement. The resected tumor showed 90% clear cells and 10% nonclear cells with capsular and vascular invasion. The cytoplasmic vacuoles in the clear cells were 3+ for oil red O stain in touch imprint cytology. Immunohistochemistry demonstrated thyroglobulin positivity in the nonclear neoplastic cells, whereas most of the clear cells were negative. Ultrastructural study demonstrated the gradual transition from protein synthesis to lipid synthesis as the neoplastic cells progressed from nonclear to clear. The study suggested that the lipid accumulation resulted from the uncontrolled fatty acid synthesis in the neoplastic cells rather than metaplasia. The karyotype of the tumor cells was normal, 46XX. Literature of lipid-rich thyroid neoplasms were reviewed.

Adenocarcinoma, Clear Cell↗
PubMed1999

Preparation and identification of activity of anti-HPV-6b/11E1 universal ribozyme--Rz1198 in vitro.

AIM: To study the preparation and cleavage activity of Rz1198 directed against HPV-6bE1 and HPV-11E1 (HPV-6b/ 11E1) transcripts in vitro. METHODS: HPV-6b/11E1 gene fragments were cloned into T-vector under the control of T7 promoter. 32P-labeled HPV-6b/11E1 transcripts as target-RNAs were transcribed in vitro and purified by PAGE. Rz1198 gene designed as a universal ribozyme for both HPV-6b/11E1 transcripts was cloned into vector p1.5 between 5'-cis-Rz and 3'-cis-Rz. 32P-labeled Rz1198 transcript was gel-purified, incubated with target-RNAs at different conditions and autoradiographed after denaturing gel-electrophoresis. RESULTS: Rz1198 was active at 37 degrees C. The optimal temperature was 50 degrees C. For HPV-6bE1, km = 12.2 nmol/L, kcat = 0.18 min(-1); For HPV-11E1, km = 14.7 nmol/L, kcat = 0.14 min(-1). All these revealed that the design of Rz1198 was correct. It could be a universal ribozyme for the two substrates--HPV-6bE1 and HPV-11E1 transcripts. CONCLUSION: Rz1198 prepared in vitro possesses the perfect specific catalytic cleavage activity. It leads to the expectation that, in the future, it will be possible to develop a new nucleic acid drug from Rz1198 which can efficiently inhibit the replication of HPV-6b/11 DNA in vivo.

Papillomaviridae↗
PubMed1999

[The experimental study of membrane-guided tissue regeneration of bone].

OBJECTIVE: To confirm membrane-guided tissue regeneration in the healing course of segmental bone defects and study the mechanism. METHODS: Segmental, 1 cm osteoperiosteal defects were produced in both radii of 12 rabbits. One side was covered with hydroxyapatite/polylactic acid(HA/PLA) membrane encapsulated as a tube. The contralateral side served as an untreated control. Healing courses were detected by radiographic and histologic examinations. RESULTS: All control sides showed nonunion, whereas there were consistent healing pattern in test sides. CONCLUSION: Membrane technique can promote bone regeneration.

Animals↗
PubMed1998

A dinucleotide mutation in the endothelin-B receptor gene is associated with lethal white foal syndrome (LWFS); a horse variant of Hirschsprung disease.

Lethal white foal syndrome (LWFS) is a congenital anomaly of horses characterized by a white coat colour and aganglionosis of the bowel, which is similar to Hirschsprung disease (HSCR). We decided to investigate possible mutations of the endothelin-B receptor gene ( EDNRB ) in LWFS as recent studies in mutant rodents and some patients have demonstrated EDNRB defects. First, we identified a full-length cDNA for horse EDNRB . This cDNA fragment contained a 1329 bp open reading frame which encoded 443 amino acid residues. The predicted amino acid sequence was 89, 91 and 85% identical to human, bovine and mouse as well as rat EDNRB respectively, but only 55% identical to the human, bovine and rat endothelin A receptor (EDNRA). Secondly, sequence analysis, together with allele-specific PCR and the amplification-created restriction site (ACRS) technique, revealed a dinucleotide TC-->AG mutation, which changed isoleucine to lysine in the predicted first transmembrane domain of the EDNRB protein. This was associated with LWFS when homozygous and with the overo phenotype when heterozygous.

Animals↗
PubMed1997

Cytopathologic features of hepatic epithelioid hemangioendothelioma.

We present the cytological features of hepatic epithelioid hemangioendothelioma (EH), which is considered to be a vascular proliferation of intermediate malignant potential. The case report concerns a 52-yr-old previously healthy man discovered to have multiple hepatic masses upon evaluation for abnormal liver function tests. Fine-needle aspiration demonstrated a neoplasm composed of interanastomosing epithelioid cells that contained intracytoplasmic lumens. Histologic sections, immunohistochemistry, and ultrastructural evaluation were confirmatory. Although hepatic EH is a rare tumor, its characteristic cytological, histological, and ultrastructural features permit a straightforward diagnosis. It is important to distinguish this entity from adenocarcinoma and angiosarcoma because long-term disease-free survival is possible, especially in the setting of orthotopic liver transplantation.

Biopsy, Needle↗
PubMed1997

Clear nuclei of papillary thyroid carcinoma conspicuous in fine-needle aspiration and intraoperative smears processed by ultrafast papanicolaou stain.

The Orphan Annie-eyed clear nucleus, defined as a large, optically clear nucleus, devoid of chromatin strands, with sharp chromatin rim, is a more specific feature than are nuclear grooves or intranuclear cytoplasmic inclusions in papillary thyroid carcinoma. In addition, this characteristic nuclear feature is detectable at low magnification. Although these clear nuclei are routinely seen in paraffin sections, they are inconspicuously seen in conventionally processed touch-imprints and fine-needle aspiration (FNA) smears. Among our two institutions, there have been 148 thyroid cases processed by Ultrafast Papanicolaou stain (UFP), including 43 papillary carcinomas, 38 cellular follicular lesions, and 67 cases of nodular hyperplasia. We observed clear nuclei in all of the cases of UFP-processed FNA and intraoperative smears of papillary carcinoma but not of other thyroid lesions. The clear nuclei are most evident in tumor cells with direct contact to the glass slide and are not seen in tumor cells soaked in cystic fluid. UFP is a valuable way to detect Orphan Annie-eyed clear nuclei of papillary thyroid carcinoma early in the diagnostic evaluation, either at immediate on-site evaluation of FNA or at intraoperative consultation and before the availability of permanent sections.

Biopsy, Needle↗