Biomedical subjects

C Y Li

Publications and source records attributed to C Y Li.

At least 289 records · Page 16Linked to original sources

PubMed1990

Macrophage responses in inflammatory demyelinating neuropathies.

Macrophages are prominent participants in inflammatory demyelinating neuropathies. To provide a different means of evaluating macrophage behavior, we used immunostaining of teased nerve fibers and endoneurial blood vessels. We assessed the frequency with which macrophages were seen in inflammatory demyelinating neuropathies, their relationship to normal and demyelinating fibers, and their expression of major histocompatibility Class II markers (Ia antigen). In 6 patients with chronic inflammatory neuropathy and 1 with Guillain-Barré syndrome, we found regularly that macrophages were adherent to teased blood vessels. Cells presumed to be entering the nerve were elongated, often with a polarized appearance suggesting motility, and were Ia-positive. After entry into nerve, the Ia-positive macrophages were adherent to both normal and demyelinating fibers. They often retained their Ia positivity after penetrating into the nerve fiber and removing myelin. Foamy macrophages, judged to be postphagocytic, were Ia-negative. The foamy macrophages found adhering to blood vessels were presumed to be leaving the nerve. This pattern of entry as Ia-positive prephagocytic cells and evolution to Ia-negative foamy macrophages was compared with other experimental and human neuropathies.

Demyelinating Diseases↗

PubMed1990

Studies on human CFU-Mix microvolume culture by use of limiting dilution assay.

By use of limiting dilution assay we investigated the bipotent and pluripotent hemopoietic progenitor cells (CFU-Mix) from 21 normal adults, cultured for 32 times. The CFU-Mix counts were 35.7 colonies/10(6) bone marrow cells. According to different cellular elements they could be divided into 5 groups, namely GEMM, GE, GL, GMeg and GM phi. It was suggested that differentiation of the stem cell is of stochastic process, influenced by different hemopoietic growth factors and cellular microenvironment. Our model seems to be suitable for studying differentiation of the stem cells. The rates of 3H-TdR and 55 + 59Fe incorporation were determined, and the 2nd day of culture was found to be the delayed stage of cell growth.

Adolescent↗

PubMed1990

Scanning electron microscopic observation of CFU-mix of normal adults and leukemic patients including two cases of myeloid-lymphoid bipotent leukemia.

We observed CFU-Mix of 4 normal adults and 11 cases of leukemia. The culture system used by us in this study represented a suitable model for studying differentiation of hemopoietic stem cells in vitro. The pathogenesis of myeloid-lymphoid bipotent leukemia were malignant changes in pluripotent hemopoietic progenitor cells. The leukemic clones showed proliferation, but did not mature in culture. It is suggested that differentiation of leukemic stem cell did not pass through CFU-Mix stage.

Adult↗

PubMed1990

Transmission electron microscopic observation of CFU-mix culture in normal adults and leukemia patients.

By use of transmission electron microscope we demonstrated that the limiting dilution assay is an important method for investigating differentiation of hemopoietic cells in vitro. If various growth factors were added into this culture system, the stem cells of normal adults could differentiate into erythrocyte, granulocyte, megakaryocyte and macrophage, while leukemic progenitor cells could not. The colony forming cell in leukemia still had the nature of leukemic cell.

Adult↗

PubMed1990

Comparison of tartrate resistant acid phosphatase in a giant cell bone tumor and a spleen infiltrated with hairy cells.

Acid phosphatase (E.C.3.1.3.2) in a giant cell bone tumor and a spleen infiltrated with hairy cells was extracted by citrate buffer and then by 0.3 mol/L NaCl. The cationic acid phosphatase in the crude extract was isolated by CM-cellulose chromatography, and further separated by high pressure liquid chromatography. The majority of the tartrate resistant acid phosphatase in the hairy cell spleen was unabsorbed on CM-cellulose and was insensitive to iron. A much larger portion of the acid phosphatase in the bone tumor, than in the spleen, was cationic and was eluted from the column by 0.8 mol/L NaCl. The cationic acid phosphatase was further separated into consecutive peaks of acid phosphatases with different sensitivity to iron. A major portion of acid phosphatase in the giant cell bone tumor was enhanced by iron, while the amounts of iron-enhanced and iron-insensitive acid phosphatase were about the same in the spleen. The differences of the phosphatases in these two types of pathologic specimens indicate the occurrence of two types of enzymes with different biological significance.

Acid Phosphatase↗

PubMed1990

Confirmation of lymphomatous pulmonary involvement by immunophenotypic and gene rearrangement analysis of bronchoalveolar lavage fluid.

Pathologic diagnosis of pulmonary involvement with lymphoma has traditionally necessitated open-lung biopsy in most cases. Specimens large enough to allow recognition of characteristic cytologic and architectural changes are usually not obtained bronchoscopically. Even when adequate biopsy specimens are available, however, unequivocal differentiation of lymphoma from benign inflammatory proliferative lesions (for example, pseudolymphoma or lymphocytic interstitial pneumonitis) is not possible on the basis of light microscopic findings alone. Pathologists have relied on immunohistologic examinations in which antibodies directed against B-cell and T-cell surface antigens are used to help distinguish benign from malignant lymphoid proliferations. Unfortunately, even immunohistologic findings may be nondiagnostic, particularly in T-cell lymphomas and in cases in which lymphoma is surrounded by a benign reactive lymphocytosis. Recent development of molecular biologic techniques (for example, Southern blotting) has provided the ability to detect a monoclonal population of cells based on detection of rearrangements of the genes that encode either B-cell immunoglobulin proteins or T-cell antigen receptor proteins. This technique is capable of detecting a clone of cells even when they constitute as little as 5% of a lymphoid infiltrate. Bronchoalveolar lavage can provide samples of sufficient size to facilitate Southern blotting. We present the first case wherein pulmonary involvement with a B-cell lymphoma was confirmed by both immunohistologic and molecular biologic studies of bronchoalveolar lavage fluid.

B-Lymphocytes↗

PubMed1990

A new murine monoclonal antibody for the diagnosis of erythroleukemia.

The authors have developed a murine monoclonal antibody, RC-82.4, against an antigen expressed by a human erythroleukemia cell line OCI-MIR. The antibody reacts with an antigen expressed by proerythroblasts, normoblasts, and some reticulocytes but not expressed in erythrocytes, granulocytes, monocytes, megakaryocytes, plasma cells, or lymphocytes. The authors have established an immunocytochemical method for studying bone marrow smears with RC-82.4. By studying bone marrow smears from 11 patients with M-6 erythroleukemia and 104 patients with various other hematologic and nonhematologic malignancies, the authors have found that RC-82.4 has great sensitivity and specificity in recognizing erythroid differentiation in blasts. The authors have used RC-82.4 and antihemoglobin antibodies to identify erythroblasts in acute and secondary acquired cases of erythroleukemia that would have been unclassifiable by morphologic and all other conventional cytochemical and immunocytochemical criteria.

Adult↗

PubMed1990

Subungual leukemia cutis.

A 79-year-old man had generalized humping of the nails and subungual tumors involving several fingers and the left big toe. Findings on histologic study of the tumor, together with the pattern on the peripheral blood smear, established the diagnosis of chronic lymphocytic leukemia. To the best of our knowledge, this is the first reported case of chronic lymphocytic leukemia involving the subungual area. The authors' observation emphasizes the importance of taking a biopsy specimen in the differential diagnosis of subungual tumors.

Aged↗

PubMed1990

Non-immune hydrops fetalis.

This article reviews the various aspects of non-immune hydrops fetalis, including the historical background, aetiology, clinical presentation, antenatal diagnosis and perinatal management, as well as presenting some data on cases of non-immune hydrops fetalis treated in the newly established Obstetrics Department of the Chinese University of Hong Kong at the Prince of Wales Hospital.

Female↗

PubMed1990

[Effect of acetylcholine on membrane potential in toad dorsal root ganglion neurons and its ionic basis].

Intracellular recordings were made to investigate the effect of acetylcholine (ACh) on membrane potential of neurons in isolated toad dorsal root ganglion (DRG). In the 73 neurons examined, 67 were of type A, and the remaining 6 of type C cell. The resting membrane potential of these two types of cells was -67.5 +/- 1.3 mV (mean +/- SE). During the application of ACh (4 x 10(-4)-6 x 10(-4) mol/L) four types of the membrane potential changes were observed: (1) hyperpolarization of 9.1 +/- 3.0 mV (mean +/- SE, n = 23); (2) depolarization of 12.9 +/- 2.2 mV (mean +/- SE, n = 20); (3) biphasic response, i.e., hyperpolarization of 8.0 +/- 2.4 mV (mean +/- SE) followed by depolarization of 10.9 +/- 3.1 mV (mean +/- SE, n = 24); (4) no change (n = 6). The hyperpolarization induced by ACh could be blocked by atropine (1.3 x 10(-5) mol/L, n = 23), and ACh-induced depolarization could be abolished by coperfusion of d-tubocurarine (1.4 x 10(-5) mol/L) and hexamethonium (1.4 x 10(-5) mol/L, n = 18). During ACh hyperpolarization the membrane conductance was increased by 13.8% and the reversal potential was about -96 mV (n = 3). TEA (20 mmol/L) enhanced ACh depolarization amplitude by 48.2 +/- 3.2% (mean +/- SE, n = 6), and depressed ACh hyperpolarization by 79.4 +/- 4.3% (mean +/- SE, n = 8), MnCl2 (4 mmol/L) decreased the ACh depolarization and hyperpolarization by 54.2 +/- 7.2% (mean +/- SE, n = 5) and by 69.2 +/- 6.4% (mean +/- SE, n = 14) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1989

Attention and eye movement related activation of neurons in the dorsal prelunate gyrus (area DP).

Neurons in area DP, the dorsomedial portion of the prelunate gyrus of awake monkeys (Macaca mulatta and Macaca sylvana), responded only little if at all to stationary or moving light stimuli. Circumscribed receptive fields could not be determined in the majority of cells. About 25% of the units became active at a certain gaze position, mostly ipsilateral to the recording site, and with a latency of 70-150 ms after the eye had attained this position with a saccade. About 70% of neurons were activated vigorously when the monkey looked attentively at an object, such as a face, a glove, a hand or simply towards the opening door, and explored it visually. These stimuli elicit attention as well as emotional responses. Photographed objects or faces flashed on a screen produced only little if any response. Our observations, therefore, suggest that the dorsomedial part of the prelunate gyrus may represent activities related to behavioral aspects of vision rather than to features of the visual image itself.

Animals↗

PubMed1989

Improved immunohistochemical detection of prostatic acid phosphatase by a monoclonal antibody.

A monoclonal antibody with high affinity to acid phosphatase isoenzyme 2 (Ab-AcP2) was selected to examine its binding to different normal and tumor tissues using the indirect immunohistochemical method. Both mature prostatic epithelial cells in the prostate and the highly dedifferentiated prostatic cancer cells in the bone marrow showed strong binding to the antibody. Among nonprostatic tissues, only bone marrow, breast, and kidney showed trace staining in some specimens. The specificity of Ab-AcP2 was much better than that of the polyclonal antibody to acid phospatase previously reported. When the antibody to the prostate-specific antigen (Ab-PSA) was used, weak background staining was often encountered, and weak to moderate stains were seen in the prostatic stroma, bone marrow, lung, skin, and melanoma.

Acid Phosphatase↗

PubMed1989

Wallerian degeneration in the peripheral nervous system: participation of both Schwann cells and macrophages in myelin degradation.

This study examined the role of Schwann cells and hematogenous macrophages in myelin degradation and Ia antigen expression during Wallerian degeneration of rodent sciatic nerve. To identify and distinguish between macrophages and Schwann cells we used, in addition to electron microscopy, immunocytochemical staining of teased nerve fibres and 1 microns thick cryosections. Before the appearance of adherent macrophages the myelin sheath fragmented into ovoids, small whorls of myelin debris appeared within Schwann cell cytoplasm and the Schwann cell displayed numerous lipid droplets. However, at least in large fibres most myelin degradation and removal was accomplished or assisted by macrophages, identified by their expression of the ED1 marker. These cells began entering the nerve from blood vessels by day 2, migrated to degenerating nerve fibres and adhered to nerve fibres in the regions of the ovoids. There they penetrated the Schwann cell basal lamina to occupy an intratubal position and phagocytose myelin. During Wallerian degeneration a subpopulation of ED1-positive monocytes/macrophages expressed Ia antigen; Schwann cells were Ia-negative. Ia expression by monocytes/macrophages appeared to be a transient event and was not seen in post-phagocytic macrophages, as indicated by the fact that ED1-positive phagocytes with large vacuoles were Ia-negative. Our data show that both Schwann cells and macrophages play important roles in degrading and removing myelin during Wallerian degeneration. The expression of Ia antigen during Wallerian degeneration indicates that Ia expression need not necessarily reflect specific immune events but in some instances can represent a nonspecific response to PNS damage.

Acrylamide↗

PubMed1989

Effect of acetylcholine on membrane potential in toad dorsal root ganglion neurons and its underlying ionic basis.

Intracellular recordings were made to investigate the responses of membrane potential to acetylcholine (ACh) on neurons in isolated toad dorsal root ganglion (DRG). In the 73 neurons examined, 67 were of type A, and the remaining 6 of type C cell. The resting membrane potential of these two types of cells was -67.5 +/- 1.3 mV (means +/- SE). During the application of ACh (4 x 10(-4)-6 x 10(-4) mol/L), the changes in membrane potential were as follows: 1) hyperpolarization, with amplitude of 9.1 +/- 3.0 mV (means +/- SE; n = 23); 2) depolarization, with amplitude of 12.9 +/- 2.2 mV (means +/- SE; n = 20); 3) biphasic response, i.e., hyperpolarization with amplitude of 8.0 +/- 2.4 mV (means +/- SE) followed by depolarization with amplitude of 10.9 +/- 2.1 mV (means +/- SE) (n = 24); no effect (n = 6). The hyperpolarization induced by ACh was blocked by superfusion with atropine (1.3 x 10(-5) mol/L; n = 23), while ACh depolarization was blocked by the mixture of d-tubocurarine (1.4 x 10(-5) mol/L) and hexamethonium (1.4 x 10(-5) mol/L) (n = 18). When ACh caused hyperpolarization, the membrane conductance was increased by 13.8% and the reversal potential was about -96 mV (n = 3). TEA (20 mmol/L) superfusion enhanced ACh depolarization amplitude by 48.2 +/- 3.2% (means +/- SE; n = 6), and depressed ACh hyperpolarization amplitude by 79.4 +/- 4.3% (means +/- SE; n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1989

Acute megakaryocytic leukemia (M7) in children.

We analyzed the clinical and laboratory features of eight children (median age, 20 months; range, 13 months to 11 years) with acute megakaryocytic leukemia (M7) and compared the findings with those reported in the literature. The diagnosis was supported by ultrastructural examination for platelet peroxidase or immunophenotyping for glycoprotein IIb/IIIa or the von Willebrand factor protein. Two patients had Down's syndrome. Initial findings included anemia (in all patients), thrombocytopenia (in six), myelofibrosis (in three), lytic bone lesions (in two), and pronounced leukocytosis (in one). Stem cell culture studies of peripheral blood specimens revealed an aberrant phenotype of the megakaryocytes in one patient and reversal to a normal pattern after successful therapy. Remission was achieved in seven of the eight patients after aggressive chemotherapy, and four patients remained in remission 27 to 57 months after diagnosis. Three of these four patients underwent allogeneic bone marrow transplantation. M7 leukemia is not infrequent in children younger than 3 years of age, especially in those with Down's syndrome. The availability of monoclonal antibodies specific to restricted antigens of the megakaryocytic lineage has made the diagnosis of M7 leukemia both possible and practical.

Anemia↗

PubMed1989

Diagnostic significance of levamisole-resistant alkaline phosphatase in cytochemistry and immunocytochemistry.

The authors have used two immunoalkaline phosphatase methods to study nonhematopoietic tumor tissues of four patients, one each with alveolar cell carcinoma of the lung, renal cell carcinoma, gastric adenocarcinoma, and colon carcinoma. They found, regardless of specific antibodies used, definite enzyme activity in the tumor cells of these four patients. Although it was possible to determine that the tumor cells were epithelial in origin because of their intense staining with antibodies to epithelial cell antigens, control slides labeled with nonimmune mouse ascites also contained cells with definite enzyme activity. In two of these cases, unlabeled smears were stained for alkaline phosphatase and showed that the tumor cells contained endogenous levamisole-resistant enzyme activity. This endogenous enzyme activity is not demonstrable in either the benign cells of these cases or the benign or malignant cells of other control cases. The findings suggest that the immunoalkaline phosphatase methods also have their inherent endogenous enzymic problems. They also suggest that cytochemical demonstration of levamisole-resistant alkaline phosphatase may be a useful cell marker for the identification of tumor cells in serous effusions.

Alkaline Phosphatase↗

PubMed1989

Correlation of clinical outcome with the degree of surface immunoglobulin (sIg) expression in B-cell chronic lymphocytic leukemia.

Peripheral blood from 121 consecutive adult patients with B-cell chronic lymphocytic leukemia (B-CLL) was immunophenotyped, and three groups with differing surface immunoglobulin (sIg) expression patterns were identified: Group A, 82 patients (68%) with weak sIg expression in greater than 20% of the circulating lymphocytes; Group B, 16 patients (13%) with either undetectable sIg or weak sIg expression limited to less than 20% of the lymphocytes; and Group C, 23 patients (19%) with strong sIg expression in greater than 20% of the lymphocytes. The histories of these patients were reviewed retrospectively, and the median follow-up in Groups A, B, and C was nine, ten, and nine years, respectively. Disease progression, defined as the development of cytopenia(s) (hemoglobin less than or equal to 100 g/L [less than or equal to 10 g/dL] or platelet count less than 100 X 10(9)/L [less than 100 X 10(3) microL]) and/or the development of newly palpable splenomegaly or lymphadenopathy, was least in Group B (6%) versus Group A (34%) versus Group C (30%) (P = 0.08). The incidence of hypogammaglobulinemia among patients who had protein electrophoresis performed was 7% in Group B versus 46% in Group A versus 45% in Group C (P = 0.036). The authors conclude that adult patients with B-CLL in whom sIg is undetectable or weakly expressed in less than 20% of the circulating lymphocytes may have an even more indolent clinical course than those with more widespread sIg expression.

Adult↗

PubMed1989

Studies on CFU-mix of 47 patients with leukemia and myelodysplastic syndrome.

By limiting dilution assay, CFU-Mix of 47 cases of untreated leukemia, myelodysplastic syndrome and 30 cases of normal adults were studied. It is suggested that most cases of acute nonlymphocytic leukemia, like chronic myelogenous leukemia (CML) and myelodysplastic syndrome should have defect in pluripotent hemopoietic stem cell. The CFU-Mix of acute myelogenous leukemia (AML) and CML were obviously lower than that of normal adults (p less than 0.001). By light microscopy, scanning and transmission electron microscopy, it was confirmed that the CFU-Mix colonies, of leukemic patients were chiefly composed of leukemic cells. Their incorporating rate of 3H-TdR was high in the early stage of culture, but that of 55 + 59Fe was low in the whole course. This phenomenon was quite different from that of the normal adults in that the CFU-Mix of the patients showed distinctive proliferation and differentiation into the leukemic progenitor cells.

Adolescent↗