Biomedical subjects

C Y Li

Publications and source records attributed to C Y Li.

At least 235 records · Page 13Linked to original sources

PubMed1994

Measurement of the intensity of cell surface antigen expression in B-cell chronic lymphocytic leukemia.

Immunophenotyping of peripheral blood lymphocytes from 95 patients with B-cell chronic lymphocytic leukemia (B-CLL) was performed to estimate surface membrane intensity of the HLA-DR, CD20, and light-chain antigens. Cases were classified as having weak, moderate, or strong intensity by a standard slide immunocytochemical method, and the fluorescence intensity (FI) was measured by flow cytometry in molecules of equivalent soluble fluorescence (MESF). Staining intensity was strongest for HLA-DR; with both methods, 94 cases were classified as strong. For CD20, 67% were weak, 27% moderate, and 6% strong; the mean MESF values were 31.7, 66.4, and 177.4 x 10(3), respectively (P < .001). Thirty-nine percent had weak surface light-chain staining, 50% moderate, and 11% strong; the mean MESF values were 4.9, 7.5, and 16 x 10(3), respectively (P = .005). These results indicate that the FI of cell surface antigens can be estimated and quantified by flow cytometry. Because of the wide overlap of FI values among the three groups, an exact correlation was not found between the two methods of classifying intensity of surface antigen expression. The usefulness of these quantitative measurements needs further analysis in clinical trials.

Antigens, CD↗

PubMed1994

A perinatal audit of stillbirths in a teaching hospital in Hong Kong.

In a 5-year period, the stillbirth rate in a teaching hospital in Hong Kong was 4.4 per 1,000 total births, which accounted for 61% of the perinatal deaths. The stillbirth rate was 5.8 times higher in twin pregnancies, and 17 times higher in triplet pregnancies. One quarter of the patients were nonbooked, and 14.5% had no antenatal care. The stillbirth rates were 3.8 and 8.0 per 1,000 among the booked and nonbooked cases respectively. The major causes of stillbirths were congenital abnormalities, haemoglobin Bart disease, abruptio placentae and gestational diabetes. No specific cause could be found in 46% of cases. There were 31 intrapartum deaths, of which 5 were potentially salvageable.

Abruptio Placentae↗

PubMed1994

Elevated frequency of microsatellite mutations in TK6 human lymphoblast clones selected for mutations at the thymidine kinase locus.

A major question in carcinogenesis is, How can a normal cell accumulate multiple mutations in different genes on different chromosomes, when the mutation rate of each gene is in the range of 10(-8) to 10(-5) per cell division? We hypothesize that many mutations may not be isolated events but rather are accompanied by concomitant mutations elsewhere in the genome. To test this hypothesis, 331 independent clones selected for new mutations at the thymidine kinase (TK) locus on chromosome 17q, and 243 nonselected control clones were examined for mutations in 12 random microsatellite loci dispersed throughout the genome. A total of 24 second-site mutations were identified in the TK mutant clones, compared with 3 in the control clones not selected for mutations at TK. The mutations include small deletions, insertions, and loss of heterozygosity. These results provide evidence that a global trans-acting mutagenic process exists in human cells. The activation of this process could be responsible for causing multiple essential mutations in tumor cells.

Base Sequence↗

PubMed1994

Phase I study of combined 2-chlorodeoxyadenosine and chlorambucil in chronic lymphoid leukemia and low-grade lymphoma.

PURPOSE: We conducted a dose-escalation study of 2-chlorodeoxyadenosine (2-CdA) added to a standard fixed dose of chlorambucil to evaluate the toxicity of the combined regimen in patients with chronic lymphocytic leukemia (CLL) and low-grade lymphoma. PATIENTS AND METHODS: A total of 15 adults with relapsed or refractory CLL or low-grade lymphoma were to receive chlorambucil orally (30 mg/m2) every 2 weeks. Also, groups of three patients were to receive escalating doses of continuous intravenously administered 2-CdA at 1, 2, or 4 mg/m2/d for 7 days repeated at monthly intervals. All patients had pharmacokinetic studies during the first cycle of 2-CdA therapy; the results were compared with other institutional phase I studies in which comparable amounts of 2-CdA were administered by bolus infusion for 5 days. RESULTS: The maximal-tolerated dose of 2-CdA that could be combined with chlorambucil was 2 mg/m2/d for 7 days for a maximum of two courses. At a higher dose level of 2-CdA or at the maximal-tolerated dose level given for more than two courses, severe and protracted pancytopenia, sometimes associated with life-threatening infections, was noted. Nonhematologic toxicities were limited to moderate degrees of nausea, vomiting, anorexia, and fatigue. Results of the pharmacologic studies suggested that 2-CdA clearance was independent of administration schedule and was unaffected by concomitant administration of chlorambucil. CONCLUSION: These observations suggest the possibility of combining two cycles of continuous intravenously administered 2-CdA (2 mg/m2/d for 7 days) with standard doses of oral chlorambucil to test the efficacy of the combination regimen in phase II trials.

2-Chloroadenosine↗

PubMed1994

Hematopoietic malignancies and related disorders among benzene-exposed workers in China.

Although the relationship between benzene and acute nonlymphocytic leukemia (ANLL) is well established, most of the analytic cohort investigations examining the relationship between benzene and hematologic neoplasms have evaluated only death certificates to validate diagnoses. In a follow-up study of 74,828 benzene-exposed and 35,805 non-exposed workers in China, pathology reports, medical records, and/or histopathologic material were reviewed for all patients with hematopoietic malignancies to ensure correct classification and to provide clinicopathologic descriptions. Eighty-two patients with hematopoietic neoplasms and related disorders were identified among benzene-exposed workers, including 32 cases of acute leukemia, 7--myelodysplastic syndrome (MDS), 9--chronic granulocytic leukemia (CGL), 20--malignant lymphoma or related disorder (ML), 9--aplastic anemia, and 5 others. Among the comparison group, 13 hematologic malignancies were observed, including 6 patients with acute leukemia, 2--CGL, 3--ML, and 2 others. The hematopathologic characteristics of the benzene-exposed ANLL cases resembled those following chemotherapy or radiotherapy. ANLL in workers exposed to benzene may represent a distinct clinicopathologic entity, with characteristics similar to treatment-related ANLL, including a preceding preleukemic phase in some patients. Results in our series, one of the largest to data, also indicate that a greater diversity of hematologic neoplasms is evident among benzene-exposed workers than previously described.

Adult↗

PubMed1994

Detection of trisomy 12 by FISH in untreated B-chronic lymphocytic leukemia: correlation with stage and CD20 antigen expression intensity.

We studied cells from 30 controls and 85 cases of untreated B-chronic lymphocytic leukemia (CLL) with a fluorescence in-situ hybridization (FISH) technique utilizing a probe to chromosome 12. By use of a threshold of > 2% for trisomy 12 for the CLL cases (the mean +3 SD for controls was 1.3%), 20% (17/85) were trisomy 12. The mean % cells positive was 32.6 (median, 39.4; range, 2.4-79.1). There was a trend toward an higher incidence of trisomy 12 in patients with Rai stages 1-4 vs Rai 0 (p = 0.16). Forty-seven % (8/17) of patients with trisomy 12 had strong intensity CD20 antigen expression compared to 21% (14/68) of patients without trisomy 12 (p = 0.03). Trisomy 12 associated with CLL is easily detected by FISH with an overall incidence of 20%. This technique should be applied to larger groups of patients to confirm the potential variation among Rai stages and immunophenotypic subgroups.

Antigens, CD↗

PubMed1994

[Effect of recombinant human stem cell factor (rhSCF) on self-renewal of stem/progenitor cells of human acute myelogenous leukemia].

Using serum-free culture system and liquid/semi-solid dual culture technique, we examined the effect of rhSCF on self-renewal of the stem/progenitor cells of human acute myelogenous leukemia (AML-CFU). The results revealed that the rhSCF as a hematopoietic growth factor (HGF) exerted its effect hierarchically earlier than interleukin-3 and granulocyte/macrophage colony-stimulating factor on AML-CFU. rhSCF, whether used alone or in combination with other HGFs, showed potential maintenance of self-renewal of AML-CFU in most AML patients studied. However, considerable discrepancy existed in maintenance among various FAB types of patients or even in patients with the same FAB type. It is suggested that SCF may play an important role in the pathological development of AML.

Adolescent↗

PubMed1994

[Study and application of dual interventional embolization in patients with acute gastroesophageal variceal bleeding].

From Nov. 1991 to Nov. 1992, twelve cases of acute massive gastro-esophageal variceal bleeding with liver function grading III had been treated with dual interventional embolization (DIE). Hemostasis were successful in all patients during the acute phase. Ten partial splenic embolization (PSE) cases with their hypersplenism cured or improved. The liver function in survived cases were improved with various degree after DIE. The mechanism of DIE in the treatment of acute gastro-esophageal variceal bleeding had been discussed and the alterations in portal pressure, the histopathology of the spleen, the peripheral hematologic changes as well as the complications after DIE were analysed and discussed. The authors claimed that DIE is an alternative method in treating the advanced cirrhosis complicating massive variceal bleeding.

Adult↗

PubMed1994

Cytochemistry and immunochemistry in hematologic diagnoses.

With new understanding in the biology of hematologic diseases and the rapid progress in their treatment, it is essential to diagnose and classify the various hematologic diseases with great precision. In recent years, the cell type-specific markers have been used successfully in cell identification for more precise diagnosis and classification of neoplastic diseases. The cytochemical method for cell identification is simple and is most useful for disorders of granulocytes, monocytes/histiocytes, hairy cells, and mast cells. The immunochemical methods are particularly useful in identifying the cell types, the clonality, and the maturation of cells in the lymphoid disorders. They are also helpful in the diagnosis of disorders of the erythroid and megakaryocytic cells, as well as nonhematopoietic neoplasms with marrow involvement.

Acute Disease↗

PubMed1994

Ethnic differences in disposition of antipyrine and acetaminophen between Tibetan and Han healthy volunteers.

The differences in disposition of antipyrine and acetaminophen between Tibetan and Han healthy volunteers were studied in a randomized crossover design. The half-life of antipyrine was found to be 18.8 +/- 4.89 h in 16 Han and 15.0 +/- 3.02 h in 17 Tibetan (P < 0.05) and the clearance was 1.35 +/- 0.37 L.h-1 in Han and 1.71 +/- 0.44 L.h-1 in Tibetan (P < 0.05). The half-life of acetaminophen was 3.1 +/- 0.86 h in Han and 3.2 +/- 1.12 h in Tibetan (P > 0.05). The experimental results indicate that the disposition of antipyrine between Tibetan and Han healthy volunteers significantly differed, the clearance of antipyrine in Tibetan increased by 20%, but the disposition of acetaminophen between the two ethnic groups showed no difference.

Acetaminophen↗

PubMed1994

Development of pattern ERG and pattern VEP spatial resolution in kittens with unilateral esotropia.

PURPOSE: To follow the development of strabismic amblyopia longitudinally by comparing mean amplitudes and the visual spatial resolving ability of retinal and cortical pattern responses at various stages of postnatal development in unilateral iatrogenic convergent strabismic kittens. METHODS: Surgery to produce iatrogenic convergent strabismus was performed on 20 kittens at 3 weeks of age; three kittens were used for controls. The monocular transient pattern electroretinogram (PERG) and pattern visual evoked potential (PVEP) were recorded simultaneously on the 23 kittens throughout development. RESULTS: The PVEPs of the strabismic eyes were very reduced at 4 to 5 postnatal weeks (P < 0.01). The reduction increased at 6 to 16 weeks but was even worse at 17 to 30 weeks. The PERG of the squinting eye showed only a slight reduction in the first 4 to 5 weeks of age (P > 0.05), the decrease of responses was significant (P < 0.01) at 6 to 16 weeks and 17 to 30 weeks. At 4 to 8 weeks of age, the PVEP evoked through the unoperated eye in kittens consisted mainly of two positive components of similar amplitude. During development, the slow component decreased in comparison to the fast one, and its peak shifted forward until it merged into the fast (P100) component. CONCLUSIONS: Esotropic amblyopia did affect the PERG and the PVEP in the amblyopic eye, but the effect on the PERG was less severe, had slower onset, and did not continue as long as for the PVEP.

Amblyopia↗

PubMed1994

Differentiation between cutaneous form of adult T cell leukemia/lymphoma and cutaneous T cell lymphoma by in situ hybridization using a human T cell leukemia virus-1 DNA probe.

Adult T cell leukemia/lymphoma (ATLL) shares overlapping clinicopathological features with cutaneous T cell lymphoma (CTCL), requiring detection of monoclonal integration of proviral DNA of type 1 human T cell leukemia virus for its differential diagnosis from the latter. We applied in situ hybridization (ISH) and polymerase chain reaction (PCR) to paraffin sections from 63 Japanese autopsy cases that had been diagnosed as CTCL in earlier years when ATLL was still not widely known. Eleven and two cases with confirmed diagnoses of ATLL and CTCL served as positive and negative controls, respectively. It was found that ISH was positive in 7 of 63 test cases and 10 of 11 positive controls, whereas PCR was positive in none of the test cases and eight of the positive control cases. Two negative controls were negative for both ISH and PCR. We conclude that ISH is superior to PCR for detecting type 1 human T cell leukemia virus proviral DNA on paraffin sections and that the ISH method is useful for differentiating CTCL from the cutaneous form of ATLL.

Base Sequence↗

PubMed1993

Acute motor axonal neuropathy: a frequent cause of acute flaccid paralysis in China.

In northern China, annual epidemics of acute-onset flaccid paralysis diagnosed clinically as Guillain-Barré syndrome have been recognized for at least 20 years. On the basis of an historical analysis of more than 3,200 patients, distinctive features include most cases occurring during the summer months among children and young adults, most of whom reside in rural areas. Of 90 patients with acute flaccid paralysis, 88 had a distinctive pattern that shares clinical and cerebrospinal fluid findings with demyelinating Guillain-Barré syndrome, but that differs from Guillain-Barré syndrome physiologically and pathologically. The clinical course is marked by rapidly progressive ascending tetraparesis, often with respiratory failure, but without fever, systemic illness, or sensory involvement. Cerebrospinal fluid is acellular, and elevations of protein content occur in the second or third week of illness. Electrodiagnostic studies show normal motor distal latencies and limb conduction velocities, but reduced compound muscle action potential amplitudes. Sensory nerve action potentials and, when elicitable, F waves are within the range of normal. Recovery is usually good. Autopsy studies have shown Wallerian-like degeneration of motor fibers. These studies establish that this is a distinctive syndrome, distinguishable from poliomyelitis and demyelinating Guillain-Barré syndrome.

Acute Disease↗

PubMed1993

Spontaneously arising immortal cell line of rat retinal pigmented epithelial cells.

A continuous cell line of rat retinal pigment epithelium (RPE), named BPEI-1, has been established and characterized. Sheets of pure RPE cells, uncontaminated by choroidal or neural retinal cell types, were isolated from eyes of 7-day-old Long Evans rats and established in primary culture. The primary RPE cells became extensively spread and grew slowly for approximately 1 month, at which time a colony of small rapidly dividing cells spontaneously appeared. Following trypsinization, most of the typical primary RPE cells did not survive and were quickly outnumbered by the smaller cells, which gave rise to a cell line that was grown continuously for several hundred generations. When growing at the maximal rate in media containing 20% FBS (doubling time 18 h), the cells were fibroblastic and nearly devoid of pigment, but were capable of morphologic transition back to a pigmented, epithelioid form when cultured under low serum conditions. Evidence that these cells originated from RPE included specific immunolabeling with antibodies to cellular retinaldehyde binding protein and cytokeratin, negative GFAP immunoreactivity, and demonstration of avid phagocytosis of isolated rod outer segments by these cells. Partial characterization of choroidal cells eliminated the latter cells as possible contaminants which could have given rise to the cell line. The BPEI-1 cell line, and other rat RPE cell lines currently being developed from pigmented normal (LE, RCS rdy+p+) and retinal dystrophic (RCS p+) rats should facilitate biochemical and molecular biological approaches to study of RPE cell function in health and disease.

Animals↗

PubMed1993

Expression of NGF-receptors during immune-mediated and lysolecithin-induced demyelination of the peripheral nervous system.

Nerve growth factor receptor, expressed in Schwann cells during early development of the PNS, is rarely found in the normal mature PNS. Following nerve transection nerve growth factor receptor is re-expressed at high levels in the Schwann cells of the denervated nerve fibres. In this study we asked if demyelination caused by an immune-mediated process or by physical destruction of myelin is associated with expression of nerve growth factor receptor, and if so, what cells are positive. We examined spinal roots and sciatic nerves from rats with experimental autoimmune neuritis and sciatic nerves from rats with focal demyelination produced by local application of lysolecithin. Both in 1 micron serial cryosections and in immunostained teased nerve fibres we found that the Schwann cells that were associated with demyelinated internodes expressed nerve growth factor receptor. Immunoreactivity for nerve growth factor receptor appeared first in a perinuclear ring, probably corresponding to the Golgi complex. In completely demyelinated internodes the postmitotic Schwann cells ensheathing the axons expressed nerve growth factor receptor on their plasmalemma. Neighbouring Schwann cells with intact myelin sheaths remained nerve growth factor receptor negative. In contrast, Schwann cells of neighbouring unmyelinated fibres expressed prominent nerve growth factor receptor immunoreactivity. These data further indicate that expression of nerve growth factor receptor by Schwann cells does not require axonal degeneration, but can be stimulated by some factor associated with acute demyelination.

Animals↗

PubMed1993

The principle of parabolic feed for a fed-batch culture of baker's yeast.

A parabolic nutrient supplementation has been derived by the specific growth rate, sugar conversion rate, and Pasteur effect, followed by high qualitative and quantitative biomass production with the lowest sugar consumption. The method produced about 95% cells in the G1 phase that were more resistant to drying and aging. These features are particularly important in the process of making dry yeast. It appears that the parabolic feed method may be used to species culture that show the Pasteur effect or produce byproducts from sugar. This may be because the supplementation is in conformity with reproducible kinetic growth during the fed-batch culture.

Carbohydrate Metabolism↗

PubMed1993

Myelodysplastic syndrome: diagnostic implications of cytochemical and immunocytochemical studies.

Cytochemical and immunocytochemical studies were performed on bone marrow aspirates from 96 cases of primary myelodysplastic syndrome (MDS), 11 cases of secondary MDS, 22 cases of non-MDS hematologic disorders, and 10 cases of nondiagnostic, apparently normal marrow specimens to determine the practicality and utility of these stains for diagnosing MDS. Cytochemical studies included iron stain, periodic acid-Schiff (PAS), peroxidase, butyrate esterase, chloroacetate esterase, and double esterase stains. Immunocytochemical staining was done with monoclonal antibody HP1-1D, which recognizes the glycoprotein IIb/IIIa complex in megakaryocytes. The iron stain remained most helpful in identifying abnormal ringed sideroblasts, a feature of dyserythropoiesis, and thus in supporting the diagnosis of MDS. The PAS stain was helpful, if positive, in identifying patients with MDS; however, when it was negative, this stain did not help distinguish MDS from non-MDS hematologic disorders. The immunocytochemical stain with HP1-1D monoclonal antibody was also helpful in identifying atypical micromegakaryocytes, indicative of dysmegakaryopoiesis. Other cytochemical abnormalities were infrequently observed and were less specific for the diagnosis of MDS. The combination of two stains--for example, PAS and iron stain or PAS and double esterase--was helpful, however, in excluding MDS, inasmuch as neither the miscellaneous nor the control group stained positively with these combinations.

Bone Marrow↗

PubMed1993

Clinical features and splenic pathologic changes in patients with autoimmune hemolytic anemia and congenital hemolytic anemia.

We characterized the pathologic changes in 50 spleens from patients with autoimmune hemolytic anemia and in 13 spleens from patients with congenital hemolytic anemia. The major pathologic findings in autoimmune hemolytic anemia were mild to pronounced cord congestion and variable white pulp area, erythrophagocytosis in conjunction with an increased polymorphonuclear neutrophil reaction, and increased deposition of hemosiderin and extramedullary hematopoiesis. In contrast, both the severity and the frequency of polymorphonuclear neutrophil reactions, deposition of hemosiderin, and extramedullary hematopoiesis were less in patients with congenital hemolytic anemia, and prominent cord congestion associated with an empty or collapsed sinus was noted in patients with hereditary spherocytosis. The activity of erythrophagocytosis in the sinus was more distinct in patients with congenital hemolytic anemia, especially those with nonspherocytic congenital hemolytic anemia, than in patients with autoimmune hemolytic anemia. These findings are consistent with the existence of different mechanisms of trapping and destruction of erythrocytes in autoimmune hemolytic anemia and congenital hemolytic anemia.

Adolescent↗