Biomedical subjects

C Y Li

Publications and source records attributed to C Y Li.

At least 145 records · Page 8Linked to original sources

PubMed1998

Pancytopenia due to bone marrow necrosis in acute myelogenous leukemia: role of reactive CD8 cells.

Bone marrow necrosis is a rare clinical condition often associated with hematological malignancy. The mechanism by which malignant disease causes marrow necrosis is unknown. We present a case of a patient with newly diagnosed pancytopenia with bone marrow biopsy evidence of extensive marrow necrosis. Upon further work-up utilizing Tc bone scan directed bone marrow biopsy, a massive CD8+ T cell marrow infiltrate was discovered engulfing AML-M2 blasts. The role of Tc bone scans in the work-up of bone marrow necrosis as well as the potential mechanism of AML-M2 induced marrow necrosis in the setting of reactive CD8+ T cell infiltration is discussed.

Aged↗

PubMed1998

Multiple lymphoid nodules in bone marrow have the same clonality as underlying myelodysplastic syndrome recognized with fluorescent in situ hybridization technique.

Benign nodular lymphoid lesions are not rare in the bone marrow of patients with myelodysplastic syndrome (MDS). Herein, we report a case of MDS with clonal lymphoid aggregates in the bone marrow but without evidence of systemic lymphoma. The case of a 71-year-old man was evaluated for cytopenia. His bone marrow was initially hypocellular, with 10% blasts and a few small lymphoid aggregates. The diagnosis of refractory anemia with excess blasts was made. The disease progressed gradually, and he received erythropoietin and granulocyte colony-stimulating factor for a short time. Forty-two months later, acute leukemia (M1) developed, with 60% to 70% blasts in the bone marrow. The bone marrow also showed large aggregates of lymphocytes. Immunohistochemical study of these cells in the nodular lesions showed 50% CD3+ and 50% CD20+. Cytogenetic and molecular genetic studies revealed monosomy 7 and T- and B-cell clonal gene rearrangement. Fluorescent in situ hybridization study with centromere-specific probes of a bone marrow specimen showed monosomy 7 in both nodular lymphoid lesions and surrounding bone marrow cells, indicating that both processes originated from the same abnormal pluripotential progenitor.

Aged↗

PubMed1998

Dantrolene inhibits nitric oxide synthase in rat alveolar macrophages treated with lipopolysaccharide and interferon-gamma.

PURPOSE: To examine the effects of dantrolene on nitric oxide (NO) production and on the activity and protein expression of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide (LPS) plus interferon-gamma (IFN gamma) in rat alveolar macrophages. METHODS: Pulmonary alveolar macrophages isolated from Sprague-Dawley rats were used. After incubation of macrophages with dantrolene (1 to 100 microM) and LPS (1 microgram.ml-1) and IFN-gamma (100 u.ml-1) for 24 hr, the cell-free medium was removed for measuring the nitrite and tumour necrosis factor-alpha (TNF-alpha) levels by Griess reaction and ELISA kit, respectively. The harvested macrophages were also used to determine the activity of iNOS by using the conversion of [3H]-L-arginine to [3H]-L-citrulline method. Protein expression of iNOS was detected by Western blot analysis. RESULTS: In rats alveolar macrophages, (i) dantrolene (1 to 100 microM) caused a dose-dependent suppression of the production of nitrite and TNF-alpha induced by LPS (1 microgram.ml-1) plus IFN-gamma (100 u.ml-1) and (ii) dantrolene (100 microM) inhibited the activity (by 37 +/- 5%, P < 0.01) and protein expression (by 39 +/- 12%, P < 0.01) of iNOS in response to LPS plus IFN-gamma. CONCLUSION: Dantrolene inhibits NO production as well as the activity and expression of iNOS in alveolar macrophages treated with LPS plus IFN-gamma, which may be associated with the reduction of TNF-alpha production.

Animals↗

PubMed1998

Systemic mast cell disease associated with the hypereosinophilic syndrome.

Systemic mast cell disease (SMCD) is an uncommon disorder characterized by a proliferation of mast cells involving the bone marrow, spleen, liver, skin, and lymph nodes. Although rare, the association of SMCD and other hematologic disorders is well established. To our knowledge, however, no previously published reports have described SMCD associated with the hypereosinophilic syndrome (HES). Herein we describe two patients who had SMCD in association with HES. Both patients had evidence of cardiac eosinophilic involvement, and both responded to systemic therapy. SMCD is often associated with eosinophilia and may be associated with HES more frequently than is commonly appreciated. Because congestive heart failure is a major cause of morbidity in patients with HES, cardiac assessment in patients with eosinophilia and SMCD is important in order to identify those with eosinophilic organ involvement and treat them aggressively.

Adult↗

PubMed1998

The role of conventional cytology, immunocytochemistry, and flow cytometric DNA ploidy in the evaluation of body cavity fluids: a prospective study of 52 patients.

Fifty-two specimens of body cavity fluids from 52 patients were analyzed with conventional cytology, immunocytochemistry, and flow cytometric DNA ploidy methods to evaluate the most appropriate way of applying and interpreting immunocytochemistry and to evaluate the contribution of DNA ploidy analysis to conventional cytology in the diagnosis of body cavity fluids. The results suggest that conventional cytology still has an important role in the diagnosis of body cavity fluids. MOC 31 is the most sensitive monoclonal antibody for distinguishing benign mesothelial cells from malignant epithelial cells. Immunocytochemistry with the combination of cytokeratin, desmin, and MOC 31 with or without epithelial membrane antigen is suggested as a helpful ancillary method for the differential diagnosis of body cavity fluids. Flow cytometric DNA ploidy analysis also provides additional information in some difficult cases. Appropriate integration of clinical information and results of conventional cytology, immunocytochemistry, and flow cytometry are necessary to achieve the most accurate diagnosis in patients with effusion involving a body cavity.

Adult↗

PubMed1998

Nodular lesions of monocytic component in myelodysplastic syndrome.

We report 4 unusual cases of myelodysplastic syndrome with distinct persistent nodular lesions noted on serial bone marrow examinations, even during remission. The lesions were predominantly composed of immature monocytes that stained positively for CD68. Trisomy 9 and 11 were demonstrated in the cells of the nodular lesions and surrounding marrow of 1 patient, indicating the same clonal origin. Evaluation of p53 glycoprotein, retinoblastoma protein (pRb), proliferation-related protein (Ki-67), multiple drug-resistant enzyme glutathione-S-transferase pi, and topoisomerase IIalpha (Topo IIalpha) revealed decreased topoisomerase expression within the nodular lesions compared with the surrounding marrow and absence of Ki-67 antigen within nodular lesions. Most cells in the lesion were not in a proliferative cycle, with very low expression of Topo IIalpha, which may explain the apparent drug resistance of these nodular lesions.

Adult↗

PubMed1998

Urbanization and childhood leukaemia in Taiwan.

BACKGROUND: In the 1980s socioeconomic development was dramatically rapid in the urbanized municipalities of Taiwan due to a prospering economy. This study addressed the question: Could differences in the incidence of childhood leukaemia (age <15) be demonstrated between urban and rural communities in Taiwan between 1981 and 1990? METHODS: The log-linear regression model was used to assess the effects of age, level of urbanization, and calendar year on the variation of childhood leukaemia incidence rates between 1981 and 1990. RESULTS: Between 1981 and 1990, the overall incidence rate of childhood leukaemia increased by 20% (rate ratio (RR) = 1.2, 95% CI: 1.0-1.5). As compared to rural areas, metropolitan regions showed a significantly higher incidence rate during the study period (RR = 1.3, 95% CI: 1.1-1.6). This urban-rural difference was particularly notable among children <5 years old (RR = 1.5, 95% CI: 1.2-1.9). Dose-response analysis further indicated that risk of childhood leukaemia was monotonically associated with levels of urbanization. The significant gradient in the risk of childhood leukaemia with urbanization was contributed solely by children in the 0-4 years age group. CONCLUSIONS: We noticed a relationship between urbanization and risk of leukaemia in children. Because of a dramatic influx of people into metropolitan areas during the 1980s, our findings may have provided support for the putative association between 'population mixing' or 'population density' and risk of childhood leukaemia. Whether such association can be attributable to virus infection or other aetiologically related leukemogens warrants further investigations.

Adolescent↗

PubMed1998

The inhibition by dantrolene of L-arginine transport and nitric oxide synthase in rat alveolar macrophages.

UNLABELLED: Dantrolene decreases the free cytosolic Ca2+ level via inhibition of calcium release from the sacroplasmic reticulum. However, the effect of dantrolene on L-arginine transport and nitric oxide synthase (NOS) activity is still unknown. In this study, we examined the effects of dantrolene on L-arginine transport and activity of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide (LPS) and interferon gamma (IFN-gamma) in rat alveolar macrophages. Incubation of cells with LPS (1 microg/mL) and IFN-gamma (100 u/mL) for 24 h resulted in significant increases in nitrite production and L-arginine transport. In the presence of dantrolene (100 microM) or inhibitors of NOS, such as aminoguanidine (100 microM), N(G)-monomethyl-L-arginine (100 microM), the nitrite production and L-arginine transport were significantly inhibited compared with that in the LPS + IFN-gamma group. Furthermore, the results of kinetic analysis indicate that the suppression of L-arginine transport by dantrolene was caused by selective decrease of the velocity of transport (Vmax) without affecting the affinity (Km) for L-arginine. In addition, dantrolene also attenuated the activity of iNOS in a dose-dependent manner. We conclude that the mechanisms by which dantrolene attenuated NO synthesis may be associated with the inhibition of availability of L-arginine by reducing the affinity for L-arginine, accompanied by a parallel decrease of the activity of iNOS. IMPLICATIONS: In this study, we demonstrated that dantrolene, a drug that reduces the intracellular Ca2+ level, can inhibit L-arginine availability and inducible nitric oxide synthase activity in macrophages. Our finding may provide a novel therapeutic approach using dantrolene to prevent hypotension associated with an activation of inducible nitric oxide synthase in endotoxemia.

Animals↗

PubMed1998

Risk of leukemia in children living near high-voltage transmission lines.

We conducted a study to examine the risk of leukemia between 1987 and 1992 among children living near high-voltage transmission lines (HVTL) in three urban districts of northern Taiwan. Twenty-eight cases of leukemia among some 120,696 children aged 14 years or less were reported to the national cancer registry between 1987 and 1992. Compared with children living in households more than 100 meters away from HVTL, children living in households less than 100 meters from HVTL experienced an essentially elevated risk of leukemia (7 versus 2.88, standardized incidence ratio [SIR] = 2.43, 95% confidence interval [CI] = 0.98-5.01). The elevated risk stands when compared with all children of Taiwan alternatively (7 versus 2.60, SIR = 2.69, 95% CI = 1.08-5.55). Such elevated risk was particularly noteworthy among children aged 5-9 years. The findings suggest that children living near HVTL tend to experience an elevated risk of leukemia. Further investigations are undoubtedly needed to unveil whether such tendency may have implied the putative association between exposure to elevated magnetic fields and risk of childhood leukemia.

Adolescent↗

PubMed1998

Fast Fourier transform analysis of ventricular fibrillation intervals to predict ventricular refractoriness and its spatial dispersion.

A technique of fast Fourier transform analysis has been used to derive mean ventricular fibrillation (VF) intervals, and to confirm that these VF intervals predict ventricular refractory periods. Twenty episodes of VF were induced by a rapid ventricular pacing in 12 sheep. VF activations in a 10-second period were simultaneously acquired from 64 epicardial sites with an electrode sock. The VF electrograms were analyzed by a fast Fourier transform analysis. The dominant peak frequency of the VF spectrum in each epicardial site was converted into milliseconds and served as a mean VF interval. The dominant peak frequency of VF electrograms ranged from 8.1 to 11.5 Hz, and the corresponding mean VF intervals were 87 to 124 ms. In five sheep, the mean VF intervals and the effective refractory periods were determined by the extrastimulus technique obtained from 29 epicardial sites. There was a very good correlation between the two parameters when the effective refractory periods were determined at a basic cycle length of 300 ms (r = 0.89, P < 0.001) and 400 ms (r = 0.87, P < 0.001), respectively. VF was induced twice in eight sheep. The maximum difference in the mean VF intervals between the two VF episodes in the same sheep was 3 ms (P > 0.05). In conclusion, mean VF intervals determined by the fast Fourier transform analysis have a good reproducibility and a good correlation with ventricular refractory periods measured by the classic extrastimulus technique. The mean VF intervals could serve as an index of ventricular refractoriness.

Animals↗

PubMed1998

Alterations of nitric oxide synthase expression with aging and hypertension in rats.

The activity and protein expression of endothelial nitric oxide synthase (eNOS) and inducible NOS (iNOS) were investigated during the development of hypertension in spontaneously hypertensive rats (SHR). SHR and Wistar-Kyoto rats (WKY) were studied at three different ages: 4, 14 to 17, and 63 weeks of age. After treatment with saline or lipopolysaccharide (LPS, 10 mg/kg IV) for 3 hours, the aortas were removed for measurement of NOS activity and protein expression assay by [3H]-L-citrulline formation method and Western blot analysis, respectively. Plasma levels of nitrite/nitrate (NO2-/NO3-) and tumor necrosis factor-alpha (TNF-alpha) were also determined. At 14 to 17 weeks and 63 weeks, the basal activity and protein expression of eNOS in the aortas were significantly lower in SHR than in WKY. In addition, the aged WKY exhibited lower eNOS activity than that of adult WKY, but this change was not seen in SHR. By comparison, the basal activity and protein expression of iNOS were only observed in SHR of the 14-to-17-week group and in the 63-week group; SHR still exhibited higher activities, and these differences were further exaggerated by treatment with LPS. The basal and LPS-induced NO2-/NO3- and TNF-alpha levels in the plasma were also higher in the SHR except the 4-week group. After treatment with quinapril, the basal and LPS-induced expressions of iNOS in SHR were significantly attenuated. Our results demonstrated that alterations of activity and protein expression of eNOS and iNOS occurred in SHR. In addition, aging may reduce the activity of eNOS in WKY but not in SHR. The decline of eNOS activity and/or expression may contribute to the development of hypertension, whereas the increase of iNOS expression may be a consequence of the pathological state of vessels associated with hypertension in SHR. However, the augmented expression of iNOS in SHR was attenuated by antihypertensive therapy, suggesting that the abnormal expression of iNOS is associated with hypertension.

Aging↗

PubMed1998

Campylobacter jejuni lipopolysaccharides in Guillain-Barré syndrome: molecular mimicry and host susceptibility.

OBJECTIVE: This study was designed to determine if the presence of specific ganglioside-like moieties in Campylobacter lipopolysaccharides (LPSs) is related to the development of Guillain-Barré syndrome (GBS), and to discover how frequently such moieties, including GM1, are present in these LPSs. METHODS: We studied Campylobacter isolates and sera from seven patients with GBS (five acute motor axonal neuropathy, one acute inflammatory demyelinating polyneuropathy, and one Fisher's syndrome), and compared them with similar specimens from patients with Campylobacter enteritis alone. RESULTS: All GBS patients had antiganglioside antibodies. Anti-GM1 and anti-GD1a titers were significantly elevated in post-Campylobacter GBS, both axonal and demyelinating, compared with normal control subjects or those with uncomplicated Campylobacter diarrhea. Campylobacter isolated from patients with GBS and with enteritis alone had similar ganglioside-like moieties. CONCLUSIONS: These results indicate that patients who develop GBS respond differently to the ganglioside-like epitopes on Campylobacter than do non-GBS diarrhea patients. Our findings support a role for host susceptibility as a determinant for the outcome following Campylobacter infection. These findings have important implications for the development of vaccines against Campylobacter jejuni.

Adult↗

PubMed1998

Cervical assessment by magnetic resonance imaging--its relationship to gestational age and interval to delivery.

The aim of this cross-sectional study was to assess the uterine cervix in late pregnancy, using MRI, and to study its relationship to the gestational age and the time interval to delivery. 91 women with a singleton cephalic presenting fetus had MRI of the pelvis between 35 and 41 weeks. All had had one prior lower segment Caesarean section and no history of prior vaginal delivery. The cervical length, internal and external os diameter, cervical signal intensity and the angulation of the cervix with the cephalocaudal axis were measured on sagittal T2 weighted images and correlated with the gestational age and the interval from the MRI examination to delivery. It was found that the signal intensity of the cervical stroma increased with the gestational age. A higher signal intensity in the cervical stroma was associated with a shorter time interval to delivery. Deliveries after 40 weeks tended to occur more commonly in those with lower signal intensity in the cervical stroma and also in those with a smaller external os diameter. It is concluded that cervical softening as assessed on MRI correlated with gestational age and the time interval to delivery.

Cervix Uteri↗

PubMed1998

True malignant histiocytosis.

OBJECTIVE: To attempt to distinguish cases of true malignant histiocytosis from the clinical syndromes of so-called malignant histiocytosis with use of recent methods. DESIGN: We retrospectively studied the laboratory data and clinical course of Mayo patients who had clinical syndromes of so-called malignant histiocytosis and reviewed available paraffin-embedded tissue specimens to identify the nature of the malignant cells. MATERIAL AND METHODS: After elimination of cases of infection-associated hemophagocytic syndrome, we reviewed and studied seven cases of so-called malignant histiocytosis in patients who had undergone assessment at Mayo Clinic Rochester between 1973 and 1993. We identified histiocytes by using current morphologic, cytochemical, and immunohistochemical methods. The clonal nature of the malignant cells was identified with morphologic, cytogenetic, and molecular genetic studies. RESULTS: Only one of the seven cases had a true histiocytic origin. The malignant cells were T cells in three other cases (the cells were also CD30+ in two cases), CD30+ cells only in one case, epithelial cells in one case, and an undetermined cell type (stained positively only with antitrypsin) in one case. CONCLUSION: True malignant histiocytosis is an exceedingly rare disease, and only a few reports have clearly identified the histiocytic origin of the malignant cells. Previously, the lack of monoclonal antibodies specific to histiocytes and the absence of techniques for performing molecular genetic studies on paraffin-embedded tissue prevented the study of such cases. With newer techniques cases of true malignant histiocytosis can now be identified.

Biomarkers, Tumor↗

PubMed1998

[Dye coupling between visual cortical (area 17) neurones of adult rat--a study on brain slices].

With intracellular injection of biocytin, forty-nine neurones were successfully labeled in in vitro visual cortex (area 17) slices of the adult rat. Out of the sample dye coupling was found in 21 cases, for each injection the number of the coupled cells varying from 2 to 5 (mean 2.8 +/- 1.1). Eighteen couplings were pyramidal-pyramidal, two were pyramidal-nonpyramidal, and one was seen among non-pyramidal cells. In most cases, the coupled cells were apart from each other with a certain distance among their cell bodies (mean 43.1 +/- 24 microns). The longest distance was up to 635 microns. Most couplings (19/21) were observed within the same lamina; only two in different laminae. The dye couplings were found in laminae II/III, IV and V, but mostly in laminae II/III. We have measured membrane potential and response properties to white matter and intracellular stimulation for the coupled and non-coupled cells; no significant difference was found between them.

Animals↗

PubMed1998

A study of the use of radiological pelvimetry in a Chinese population.

BACKGROUND: To audit the use of radiological pelvimetry in a teaching obstetric unit in a Chinese population. METHODS: A prospective observational study included all radiological pelvimetries performed in one obstetric unit over 8 months. All pelvimetries were assessed by one of the authors, and the outcome of pregnancy was reviewed. RESULTS: Among 5576 women delivered in that period, 298 (5.3%) had a pelvimetry. The anteroposterior diameter of the outlet (APO) was on average 9.3 mm smaller than the obstetric conjugate (OC), and was below the definition of pelvic contraction in more than 70% of cases. Previous Cesarean sections accounted for 90.9% of the antenatal radiological pelvimetries. The result of this investigation affected the clinical management in more than 80% of these patients. The chance of successful vaginal delivery was directly related to the pelvic dimensions. CONCLUSIONS: Radiological pelvimetry may provide additional information which could facilitate the counseling of patients with a history of previous Cesarean section.

Asian People↗

PubMed1998

Endoscopic vein harvest for coronary artery bypass surgery.

BACKGROUND: Despite increased awareness of risk factors, wound complications continue to be a problem following coronary artery bypass graft (CABG) surgery. A minimally invasive alternative was therefore developed to reduce the risk of complications while providing the same benefits as the standard open vein harvest procedure. METHODS: Video-assisted endoscopic technique for vein harvest was introduced in our medical center in October 1996. The procedure was evaluated and compared with the standard open vein harvest procedure. With the endoscopic technique, small incisions were made, each about 2-3 cm at the selected access sites (groin and above and below the knee). An endopath subcutaneous dissector was subsequently inserted along the anterior surface of the saphenous vein with the assistance of an endoscope and video monitor. The venous side branches were detected and positioned using a vessel dissector. A ligaclip was applied and the branches were divided using endopath-scissors. In some cases, the venous branches were divided directly using the endopath-scissors. Therefore, the distal and proximal ends of the saphenous vein were isolated, ligated and divided. The harvested veins were used for CABG. Each patient was evaluated for length of surgery, hospital stay and morbidity. RESULTS: From October 1996 through May 1997, we performed 50 procedures using video-assisted endoscopic vein harvest. The results were compared with those from 106 patients who underwent standard open vein harvest during the same period. The rate of complications was 2% in the endoscopic group compared with 13.2% in the open group (p < 0.05). The average hospital stay was 7.2 days in the endoscopic group and 11.5 days in the open group (p < 0.05). Twelve weeks after the operation, all of the incisions healed with good cosmetic results in the endoscopic group. However, long visible scars were found in the patients in the open group. CONCLUSIONS: Endoscopic saphenous vein harvest provides a minimally invasive alternative to open vein harvest. It provides good cosmetic results without a hypertrophic scar and enables the patient to regain early ambulation.

Aged↗

PubMed1998

Halothane requirement--a comparison between laryngeal mask airway insertion and endotracheal tube intubation in pediatric patients.

BACKGROUND: The present study was to determine the effective concentration of halothane for insertion of laryngeal mask airway (LMA) and for intubation of endotracheal tube (ETT) in pediatric patients. METHODS: Forty-eight ASA class 1 patients, aged from 10 months to 6 years, scheduled for minor elective surgery were randomly assigned to two groups i.e., LMA and ETT. The concentration of halothane effective in fifty percent of patients (EC50) was determined by the up-and-down method (with 0.5% as a step size). After the predetermined concentration of halothane delivered from a calibrated vaporizer was established and maintained for 20 min, LMA insertion or ETT intubation was attempted without the patient being curarized. The response of patient to LMA or ETT was reported either as "movement" or "non-movement". The effective concentration and associated 95% confidence limits were determined in each group. RESULTS: An effective concentration of halothane for LMA insertion was 1.5 +/- 0.4% (95% confidence limits 1.4-1.7%), whereas that for ETT intubation was 2.3 +/- 0.5% (95% confidence limits 2.1-2.5%). The difference between these two values was statistically significant (p < 0.01). Airway reflexes after LMA insertion were minimal. CONCLUSIONS: The insertion of LMA could be performed at a significantly less halothane concentration in comparison with ETT intubation in children.

Anesthetics, Inhalation↗