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L L Yu

Publications and source records attributed to L L Yu.

At least 19 recordsLinked to original sources
PubMed2001

Using inductively coupled plasma-mass spectrometry for calibration transfer between environmental CRMs.

Multielement analyses of environmental reference materials have been performed using existing certified reference materials (CRMs) as calibration standards for inductively coupled plasma-mass spectrometry. The analyses have been performed using a high-performance methodology that results in comparison measurement uncertainties that are significantly less than the uncertainties of the certified values of the calibration CRM. Consequently, the determined values have uncertainties that are very nearly equivalent to the uncertainties of the calibration CRM. Several uses of this calibration transfer are proposed, including, re-certification measurements of replacement CRMs, establishing traceability of one CRM to another, and demonstrating the equivalence of two CRMs. RM 8704, a river sediment, was analyzed using SRM 2704, Buffalo River Sediment, as the calibration standard. SRM 1632c, Trace Elements in Bituminous Coal, which is a replacement for SRM 1632b, was analyzed using SRM 1632b as the standard. SRM 1635, Trace Elements in Subbituminous Coal, was also analyzed using SRM 1632b as the standard.

Calibration↗
PubMed2001

Determination of As, Cd, Cr, and Hg in SRM 2584 (trace elements in indoor dust) by high-resolution inductively coupled plasma mass spectrometry.

Standard reference material (SRM) 2584 (Trace Elements in Indoor Dust) was developed as a reference standard for evaluating field methods and for validating laboratory and reference methods for the assessment of lead contamination and exposure. In addition to lead, the toxic trace elements As, Cd, Cr, and Hg, at approximately 17, 10, 140, and 5 microg g(-1), respectively, have been certified in the SRM. These four analytes were successfully determined by use of high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Isobaric interferences at masses of As and Cr were resolved by using the high resolution mode (nominal 8000) and the medium resolution mode (nominal 3000), respectively, of the instrument. The effects of a significant drift in analyte sensitivity in the course of measurement were rectified by use of internal standardization, single spike standard addition, and an optimized analysis sequence. The results were compared with those obtained by instrumental neutron activation analysis (INAA) and isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). The results for the quality control, SRM 2704 (Buffalo River Sediment), were in good agreement with the certified values, indicated by the uncertainty intervals of the measured values overlapping the certified intervals at 95% confidence level.

Arsenic↗
PubMed2000

Anti-diarrheal effect of water extract of Evodiae fructus in mice.

Our previous study showed that Evodiae fructus (the dried, unripe fruit of Evodia rutaecarpa) has an inhibitory effect on the intestinal transit (anti-transit effect) in mice. In the present study, a water extract of Evodiae fructus was used to examine its effect on castor oil-induced diarrhea and to compare with its anti-transit effect in mice. The results indicated that Evodiae fructus had both anti-transit and anti-diarrheal effects with comparable ID(50) (the dose for 50% inhibition) values of 54+/-7 and 76+/-17 mg/kg. The time-courses of Evodiae fructus pretreatment for both anti-transit and anti-diarrheal effects were very similar. Because no significant influences of both nitric oxide (NO) precursor L-arginine (600 mg/kg, i.p.) and NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (25 mg/kg, i.p.) pretreatment, the NO system was not involved in both the anti-transit and anti-diarrheal effects of Evodiae fructus. Like Evodiae fructus, a muscarinic acetylcholine receptor antagonist atropine inhibited castor oil-induced increase in fecal weight and loss of body weight. However, the potencies or time-courses of atropine pretreatment for both anti-transit and anti-diarrheal effects were different. Furthermore, the anti-diarrheal effect of atropine was independent of its anti-transit effect at the lower dose (0.5 mg/kg, i.p.). Therefore, the action of Evodiae fructus appeared to be something different from atropine, suggesting that an action other than the anti-muscarinic action, as previously proposed for Evodiae fructus, may be involved.

Animals↗
PubMed2000

Sjögren's syndrome and granulomatous panniculitis.

An 83-year-old Cambodian woman presented with multiple painful erythematous nodules on the lower legs, forearms and wrists. Subsequent history and investigations revealed a granulomatous lobular panniculitis associated with Sjögren's syndrome. This is a rare cutaneous association of Sjögrens syndrome with only three similar case reports in the literature.

Aged↗
PubMed2000

Bioequivalence study of tramadol by intramuscular administration in healthy volunteers.

Tramadol hydrochloride (CAS 36282-47-0) is a centrally acting analgesic agent binding to mu opiate receptors. The bioavailability of a new tramadol hydrochloride injection (Limadol) was compared with a commercially available reference product by intramuscular administration in twelve healthy Chinese male volunteers by a standard two-way cross-over trial. Each volunteer received a single 100 mg injection of tramadol HCl in each phase. The bioavailability was compared using the area under the plasma concentration-time curve from time 0 to 30 h (AUC0-30), the area under the plasma concentration-time curve from time 0 to infinity (AUC0-infinity), peak plasma concentration (Cmax), and time to reach peak plasma concentration (Tmax). No statistically significant difference was observed between the Tmax, Cmax, AUC0-30 and AUC0-infinity of the two preparations. It is concluded that test and reference formulations of tramadol hydrochloride are bioequivalent for both the extent and rate of absorption after a single intramuscular injection.

Absorption↗
PubMed1999

Detection of microscopic melanoma metastases in sentinel lymph nodes.

BACKGROUND: Sentinel lymph node biopsy following radioisotope labeling is a recently developed, minimally invasive surgical staging procedure used in the management of primary cutaneous malignant melanoma. If histologic analysis reveals melanoma metastasis in the sentinel lymph node, completion lymphadenectomy is performed and adjuvant therapy considered. The routine pathologic assessment of the sentinel lymph node consists of bisecting the lymph node along its long axis and histologic examination of one hematoxylin and eosin-stained section of each cut surface. METHODS: In this study, the authors reexamined 235 sentinel lymph nodes reported as negative for melanoma metastasis following routine histologic examination, from 94 patients with American Joint Committee on Cancer (AJCC) Stage I and II cutaneous melanoma. RESULTS: Deeper sections into the lymph node and immunohistochemical stains with antibodies to S-100, HMB-45, NK1C3, and MART-1 led to the identification of microscopic metastases in 11 sentinel lymph nodes from 11 patients and capsular nevi in 9 sentinel lymph nodes from 8 patients. CONCLUSIONS: Deeper serial sections and immunohistochemical stains detected microscopic metastases in approximately 12% of cases that would be reported as negative for metastasis by routine pathologic analysis. These techniques also allowed for the identification of capsular melanocytic nevi in the sentinel lymph nodes of 9% of patients. [See editorial on pages 551-2, this issue.]

Adult↗
PubMed1999

Determination of clindamycin in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to the bioequivalence study of clindamycin.

A simple, sensitive and specific liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) method for the determination of clindamycin (I) was developed. Both I and verapamil (II, internal standard) were analyzed using a C18 column with a mobile phase of 80% acetonitrile-0.01% trifluoroacetic acid. Column eluents were monitored by electrospray tandem mass spectrometry. Multiple reaction monitoring (MRM) using the parent to daughter combinations of m/z 425-->126 and 455-->165 was used to quantitate I. A limit of quantitation of 0.0500 microgram/ml was found. The assay exhibited a linear dynamic range of 0.0500-20.0 micrograms/ml and gave a correlation coefficient (r2) of 0.998 or better. The chromatographic run time was approximately 2 min. The intra-batch precision and accuracy of the quality controls (QCs, 0.0500, 0.150, 1.50, 15.0 and 20.0 micrograms/ml) were characterized by coefficients of variation (CVs) of 5.13 to 13.7% and relative errors (REs) of -4.34 to 4.58%, respectively. The inter-batch precision and accuracy of the QCs were characterized by CVs of 4.35 to 8.32% and REs of -10.8 to -4.17%, respectively. The method has successfully been applied to the analysis of samples taken up to 12 h after oral administration of 300 mg of I in healthy volunteers.

Anti-Bacterial Agents↗
PubMed1999

The morphological features of locally recurrent melanoma and cutaneous metastases of melanoma.

Local recurrence of melanoma at the primary excision site usually implies that the primary excision was incomplete or "inadequate" and that the recurrence was attributable to retained primary melanoma cells or occult melanoma metastases in the adjacent tissue. Pathologists frequently report these tumors in the scar as recurrent or residual melanoma, apparently without considering the possibility that they may be local metastases and manifestations of systemic disease. In this study of 72 cases, we have shown that the morphological features of locally recurrent melanoma, excluding persistent incompletely excised primary melanoma, and cutaneous metastases of melanoma were identical. Because the prevention of local recurrence is the main reason for wide excision of melanoma beyond complete excision of the primary tumor itself, it is essential that pathologists should classify these neoplasms precisely as either persistent incompletely excised primary melanoma or metastatic melanoma.

Diagnosis, Differential↗
PubMed1998

Central inhibitory effects of water extract of Acori graminei rhizoma in mice.

The present study evaluated in mice the central inhibitory effects of a water extract of shichangpu (Acori graminei rhizoma (AGR), the dry rhizome of Acorus gramineus Soland. (Araceae)). AGR (0.5-5.0 g/kg) dose-dependently decreased the locomotor activity and increased the pentobarbital-induced sleeping time, but had no significant effect on the treadmill performance. AGR also dose-dependently inhibited the intensity of apomorphine-induced stereotypic behavior. At the highest dose (5.0 g/kg), AGR had a weak anticonvulsant effect on the pentylenetetrazol-induced seizures. Receptor binding assays showed that AGR competed with [3H]SCH-23390 and [3H]YM-09151-2 for specific binding to striatal dopamine D1 and D2 receptors with Ki values of 5.6 and 4.2 mg/ml, respectively. AGR also competed with [3H]muscimol for specific binding to the gamma-aminobutyric acid (GABA) binding site of cortex GABA(A) receptors with a Ki value of 0.31 mg/ml. It also increased the specific binding of [3H]flunitrazepam to the benzodiazepine binding site of the GABA(A) receptors, suggesting a GABA agonist-like action. These results suggested that the central inhibitory effects of AGR were probably effected through an action on the central dopamine receptors and GABA(A) receptors. The principle of AGR acting at these ligand binding sites was not alpha-asarone, one of the important principles of AGR, since that alpha-asarone (10(-6)-10(-4) M) had no significant interactions with these binding sites.

Animals↗
PubMed1998

Intralesional cytokine therapy in cancer: a pilot study of GM-CSF infusion in mesothelioma.

Systemic cytokine therapy in cancer has major side effects, and we reasoned that the local infusion of cytokines into tumors could induce local immunologic responses with minimal toxicity and potentially strong systemic anticancer effects. This study investigated the toxicity and effectiveness of intralesional granulocyte/macrophage-colony-stimulating factor (GM-CSF) infusion in solid-tumor masses. We studied 14 patients (12 men, two women) with malignant mesothelioma (MM), aged 60 years (range, 46-70 years), with stage 2 disease, in whom the tumor was of sufficient size and accessibility for an intralesional catheter to be inserted. Recombinant human GM-CSF (Molgramostim; Schering Plough) was infused intralesionally for 8 weeks, by using a portable pump, at a dose of 2.5-10 micrograms/kg/day. One patient using GM-CSF developed histologically confirmed necrosis of tumor surrounding the distal catheter, one developed a marked lymphocytic infiltrate in the tumor and had a partial response measured by chest computed tomography (CT) scan, 10 progressed, and three had no response. Neutrophilia with morphologic evidence of neutrophil activation and clinical features suggestive of neutrophil plugging of blood vessels occurred at doses > 5 micrograms/kg/day. In vitro, GM-CSF doubled human neutrophil/CD11b/CD18 expression, suggesting that neutrophil clumping as seen in vivo might be due to integrin upregulation. Intralesional infusion of cytokines is feasible but can be associated with systemic toxicity and has considerable technical problems. It produces a localized immune reaction with tumor regression in a minority of patients.

Aged↗
PubMed1995

Evaluation with receptor binding assay on the water extracts of ten CNS-active Chinese herbal drugs.

In the present study, we established receptor binding assays to evaluate the water extracts of ten central nervous system (CNS)-active Chinese herbal drugs. These ten herbal drugs are Chaihu (Radix Bupleuri), Chuanxiong (Rhizoma Chuanxiong), Danggui (Radix Angelicae sinensis), Danshen (Radix Salviae miltiorrhizae), Duhuo (Radix Angelicae pubescentis), Hangqin (Radix Scutellariae), Qinjiao (Radix Gentianae macrophyllae), Shengma (Rhizoma Cimicifugae), Suanzaoren (Semen Zizphi spinose), and Yangjihua (Flos Daturae). The results indicated that these water extracts contained the principles acting on the dopamine (D1 & D2), muscarinice acetylcholine (M1), or 5-HT (5-HT1A & 5-HT2) receptors, or the benzodiazepine and the gamma-amino-n-butyric acid (GABA) binding sites of GABAA receptors as determined by receptor binding assays. The receptors or binding sites which predominantly acted by each water extract are listed as follows: Chaihu: D2, 5-HT1A, GABA; Chuanxiong: GABA, 5-HT1A; Danggui: GABA, 5-HT1A; Danshen: BDZ; Duhuo: GABA, 5-HT1A, D2, D1; Hangqin: BDZ, D1, 5-HT1A; Qinjiao: GABA, BDZ, 5-HT1A, D2; Shengma: 5-HT1A; Suanzaoren: 5-HT1A, 5-HT2, GABA; Yangjihua: M1, 5-HT1A, 5-HT2. These results provided evidence to explain the CNS effects of these herbal drugs at the receptor level. Furthermore, these results provided information to direct the isolation and purification of receptor-interactive compounds from these herbal drugs.

Animals↗
PubMed1994

Effect of the crude extract of Evodiae Fructus on the intestinal transit in mice.

One of the uses of Evodiae Fructus (EF, the dried, unripe fruit of Evodia rutaecarpa) in Chinese medicine is recommended in diarrhea, but its underlying mechanism has not yet been studied. The present study examined the effect of an aqueous extract of EF on the intestinal transit in mice by the charcoal meal method. Intraperitoneal administration (i.p.) of EF (1.9-30 g/kg) significantly inhibited the intestinal transit in a dose- and time-dependent manner. This inhibitory effect of EF was not attenuated by the i.p. pretreatment with an alpha 2-, alpha 1-, or beta-adrenoceptor antagonist, i.e. yohimbine (10 mg/kg), prazosin (2 mg/kg), or propranolol (6 mg/kg), respectively. In the isolated mouse duodenum, jejunum, and ileum preparations, EF (10-50 mg/ml) concentration-dependently abolished 10 microM carbachol-induced contraction with an IC50 of 9.9, 11.7, and 16.3 mg/ml, respectively. This inhibitory effect was not competitive. Receptor binding assay showed that EF (1-50 mg/ml) significantly competed with [3H]-N-methylscopolamine for specific binding to muscarinic receptors on the duodenum, jejunum, and ileum membrane preparations with a Ki value of 7.1, 8.4, and 14.4 mg/ml, respectively. Therefore, the above results suggested that the inhibitory effect of EF on intestinal transit was probably via an action directly on the muscarinic receptors but not on the alpha 2, alpha 1-, and beta-adrenoceptors in the small intestine.

Animals↗
PubMed1994

Stereotactic biopsy of 100 intracerebral lesions at Sir Charles Gairdner Hospital.

The pathological findings in a retrospective review of 100 consecutive intracranial stereotactic biopsies are presented. Definite diagnosis could be established in the majority (89) of cases and included 85 neoplasms (69 primary cerebral tumors, 10 non-Hodgkin's lymphomas and 6 metastases) and 4 non-neoplastic processes. In the remaining 11 samples the findings were non-diagnostic; 2 consisted of normal glial tissue, while the remainder variously showed changes of necrosis, hematoma, histiocytic reaction or astrocytic proliferations of uncertain nature. Verification of the stereotactic diagnosis by examination of lesional tissue obtained at subsequent craniotomy or postmortem was possible in 7 of 10 cases. Two broad categories of diagnostic difficulty were identified in interpreting stereotactic biopsies: (1) accurate tumor typing and grading, and (2) the distinction between reactive and neoplastic astrocytic proliferations. Two essential components in the diagnostic process are: (1) careful correlation with the clinical and radiological findings; and (2) use of intraoperative smear and/or frozen section preparations to confirm specimen adequacy. By adhering to these principles accurate intraoperative diagnosis can usually be established, particularly for high grade astrocytoma, lymphoma and metastasis. Tumor typing is aided by the use of immunohistochemistry and ultrastructural examination and the examination of serial sections is of value in grading.

Adolescent↗
PubMed1994

Mucinous cystadenoma of the appendix with unusual sonographic appearances.

A case of an appendiceal cystadenoma resulting in a large mucocele in a 35 year old man presenting with abdominal pain is reported. On ultrasonography, an unusual appearance of strand-like layers of varying echo-texture suggesting a solid lesion was seen. On computed tomography, calcification and contrast enhancement of the rim was noted. The spectrum of imaging appearances of appendix mucoceles is reviewed.

Adult↗