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Biomedical subjects

C Y Li

Publications and source records attributed to C Y Li.

At least 217 records · Page 12Linked to original sources
PubMed1995

A simple and comprehensive method for the construction, repair and recycling of single and double tungsten microelectrodes.

A method for the construction, repair and recycling of tungsten-in-glass micro-electrodes is described. Essentially, the method employs insulating tungsten electrodes by collapsing borosilicate-glass capillaries onto tungsten wires. Procedures are described for either (1) removing excess glass insulation from the microelectrode tip or (2) fine adjustment and reshaping of the exposed electrode tip. This approach enables the controlled shaping of the electrode tip during preparation and/or reshaping the electrode tip or glass insulation of damaged electrodes. The method may be applied in the preparation of bipolar tungsten-in-glass electrode and tungsten electrode/micropipette assemblies. Advantages of the method are discussed.

Electrophysiology↗
PubMed1995

Guillain-Barré syndrome in northern China. The spectrum of neuropathological changes in clinically defined cases.

The pathology of the Guillain-Barré syndrome remains controversial, and autopsied cases available for study by contemporary techniques are uncommon. Large numbers of cases clinically diagnosed as Guillain-Barré syndrome occur in northern China. In this study we examined the neuropathological changes in 12 autopsied cases from Hebei Province, China. Eleven died early in the course of their disease. In all cases tissue was specially handled and fixed for electron microscopy and for immunocytochemistry. Three of these 12 cases had typical acute inflammatory demyelinating polyneuropathy (AIDP) with lymphocytic infiltration and macrophage-mediated demyelination, reproducing the pathological picture most often reported in Guillain-Barré syndrome in North America, Europe, and Australia. Six cases had predominantly axonal involvement, characterized by Wallerian-like degeneration of nerve fibres, with only minimal demyelination and with minimal inflammation in five. Three cases, even though paralysed at the time of death, had only very mild changes in the spinal roots and sciatic nerves. Within the group of six predominantly axonal cases, there were important differences both in the severity of the abnormalities and in the classes of fibres involved. Three cases had extensive Wallerian-like degeneration of sensory as well as motor fibres [acute motor-sensory axonal neuropathy (AMSAN)], while in the other three cases the fibre degeneration affected the motor nerve fibres almost exclusively. These latter cases establish a structural basis for the clinical and electrophysiological picture termed the acute motor axonal neuropathy (AMAN) pattern. In both the AMAN and the AMSAN patterns, a prominent feature was the presence of macrophages within the periaxonal space, surrounding or displacing the axon, and surrounded by an intact myelin sheath. These studies show that the early pathological changes in cases clinically diagnosed as the Guillain-Barré syndrome are diverse and not restricted to the well-known pattern of AIDP, and that the predominant pathological patterns may differ in different parts of the world. The differences in pathological findings between acute inflammatory demyelinating polyneuropathy and the axonal patterns are likely to reflect differences in the pathogenetic mechanisms. The periaxonal macrophages in the axonal patterns suggest that an important epitope may be localized to the axolemma or periaxonal space. The mild cases indicate that severe paralysis can occur early in Guillain-Barré syndrome without prominent structural changes along the nerve, suggesting that physiological block or nerve terminal changes may be implicated.

Acute Disease↗
PubMed1995

Guillain-Barré syndrome in northern China. Relationship to Campylobacter jejuni infection and anti-glycolipid antibodies.

Guillain-Barré syndrome has been considered to be primarily an acute inflammatory demyelinating polyneuropathy (AIDP). Our experience with Guillain-Barré syndrome in northern China differs from the traditional concept. Electrophysiologically and pathologically, most of our patients have motor axonal degeneration with minimal cellular inflammation, which we have termed 'acute motor axonal neuropathy' (AMAN). The current studies were undertaken to characterize prospectively the clinical, electrophysiological, and serological features of Guillain-Barré syndrome, defined clinically, in northern China. In 1991 and 1992, we characterized by electrodiagnostic criteria 129 Chinese patients with Guillain-Barré syndrome. The AMAN form was present in 65% of patients, the AIDP form in 24% and 11% were unclassifiable. For the 38 patients who presented from January to October, 1992, we performed serological assays for antibodies to Campylobacter jejuni and to glycolipids. Of these 38 patients, 55% had AMAN, 32% had AIDP and 13% were unclassifiable. Sixty-six percent of the 38 had serological evidence of recent C. jejuni infection as compared with 16% of village controls (P = 0.001). Seventy-six percent of AMAN patients and 42% of AIDP patients were seropositive. IgG anti-GM1 antibodies were more frequent in Guillain-Barré syndrome patients compared with village controls (42% versus 6%; P < 0.01). However, no statistically significant correlations were found between the pattern of disease, AMAN or AIDP, anti-glycolipid antibodies, or C. jejuni antibodies. Based on electrophysiological criteria, Guillain-Barré syndrome in northern China can be divided into two predominant forms: AIDP and AMAN. The AMAN form is more common and predominates in the yearly summer outbreaks of Guillain-Barré syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Immunohistochemical study of the spleen in chronic immune thrombocytopenic purpura. With special reference to hyperplastic follicles and foamy macrophages.

OBJECTIVE: To better understand immunologic and pathophysiologic changes in the spleen in chronic immune thrombocytopenic purpura. DESIGN: We performed immunohistochemical studies on 12 spleens of patients with immune thrombocytopenic purpura. RESULTS: Four spleens had prominent hyperplastic secondary follicles in the white pulp and trapping of platelet antigen (GPIIb/IIIa) in the germinal center. Four other spleens had hyperplastic follicles and foamy macrophages but no platelet antigen trapping in the germinal centers. Another four spleens had predominantly foamy macrophages but no hyperplastic follicles. Foamy macrophages were found mainly in the marginal zone; abundant platelet antigen (CD41) was present in their cytoplasm. CONCLUSIONS: Hyperplastic follicles in the white pulp or foamy macrophages in the marginal zone (or both) are major pathologic features in most spleens in immune thrombocytopenic purpura. The presence of platelet antigen (CD41) in the germinal centers and foamy macrophages may reflect the sites of immune reaction and platelet destruction in immune thrombocytopenic purpura.

Adolescent↗
PubMed1995

[Shape and extent of the integration field of cat's striate cortical neurones].

120 cells were recorded from area 17 of cats and their length and width summation properties were investigated by drifting sinusoidal grating patches. The study shows that (1) for most of the cells, the RF was roughly equal in length and width, while most of the integration fields (IFs) were of elongated shape either in length or in width; (2) the size of the IFs was mostly 2-7 times (mean 3.7 times) the size of the related RFs, no significant difference was seen between the simple and the complex cells; (3) the size of the IFs tends to increase with increase of retinal eccentricity of the RFs; (4) for neurones whose RF located near the vertical meridian (VM), the IF extended bilaterally into both the contra- and the ipsilateral sides to about the same extent, but the strength of the modulatory effect of the ipsilateral field is weaker than that of the contralateral field. The above results indicate that neurones of the primary visual cortex integrate visual information from an extensive visual field, and the integration effect may cross the VM to the ipsilateral side.

Animals↗
PubMed1995

[Clinical and experimental study on gastrosia convalescens in treating chronic atrophic gastritis].

Gastrosia convalescens (GC) is a new drug for treating the Spleen-Yin Deficiency syndrome of chronic atrophic gastritis (CAG). Animal experiment has shown that GC has the function of promoting the regeneration of atrophic glands, and that of anti-inflammation, reinforcing, strengthening the stomach etc. It has the effect on the intestinal electric activity in dogs, mainly exciting in action, which was superior than that of domperidoni (P < 0.05). The result of clinical study has demonstrated that the marked effective rate of GC was 78.32%, CAG reversed into chronic superficial gastritis (CSG) in 30.0% of patients (60/200 cases), CAG into chronic superficial atrophic gastritis (CSAC) in 39.0% (78/200 cases) and CSAG into CSG in 39.02% (48/123 cases). The disappearance rate of metaplasia of intestinal epithelium and atypical hyperplasia were 39.1% and 38.14% respectively. There was a very significant difference in comparing with control group (P < 0.01).

Adult↗
PubMed1995

Hyposplenic blood picture in systemic amyloidosis. Its absence is not a predictable sign for absence of splenic involvement.

We studied a total of 61 cases of systemic and senile amyloidosis to evaluate the significance of a "hyposplenic blood picture" (the presence of numerous Howell-Jolly bodies) in these patients and to correlate its presence with the pattern and severity of the splenic involvement. To ascertain whether this peripheral blood picture is prevalent with a certain type of amyloidosis, we classified all cases by immunostaining with a panel of antibodies against AL amyloid (kappa and lambda light chains), serum amyloid-associated protein, prealbumin, beta-2 microglobulin, and amyloid p component. Based on immunostaining results, all cases were classified as AL (31 cases), AA (8 cases), or senile (prealbumin-positive, 22 cases) amyloidosis. Howell-Jolly bodies were identified in six patients with amyloid L amyloidosis; of these, four cases had diffuse splenic cord involvement, one had a follicular pattern, and one had a vascular pattern. Only one of these patients had a typical hyposplenic blood picture. This patient had far-advanced diffuse splenic involvement. The remaining five patients had rare to few Howell-Jolly bodies. In addition, 12 other patients had diffuse splenic involvement with no Howell-Jolly bodies present. This study concludes that even when there is advanced diffuse replacement of splenic cords with amyloid on light microscopy, the "pitting" function of the spleen appears to be preserved in most cases. The absence of a hyposplenic blood picture cannot be equated with normal splenic cord histology in patients with systemic amyloidosis.

Amyloidosis↗
PubMed1995

Some fluorescent properties of non-enzymic transamination and measurement of the relative molecular mass of protein.

A procedure for transaminating proteins and removing the transaminated N-terminal residue has been used for studying structure-function relationship of protein (Dixon and Fields 1972, Meth. Enzymol. 25, 409-419). We show that it is convenient for measuring the relative molecular masses of proteins by measuring the glycine formed from glyoxylate during such transamination. Quinoxaline derivatives have been synthesized by the reaction of 2-oxo acids from amino acids reacting with o-phenylenediamine. 2-Oxo acids transaminated from amino acids fluoresced at around 405 nm, depending on the nature of residual side groups. The emission maximum of 3-benzyl-2-hydroxy-quinoxaline from the reaction of o-phenylenediamine with phenylpyruvate was at 363 nm. The fluorescent derivatives have been used to study conformational changes of peptides and to detect whether or not N-termini of proteins were blocked.

Glycine↗
PubMed1994

Chronic natural killer cell lymphocytosis: a descriptive clinical study.

We review the clinical manifestations and long-term outlook of patients with chronic natural killer (NK) cell lymphocytosis. After reviewing more than 1,500 peripheral blood lymphoid flow cytometry reports and molecular genetics data from patients with suspected large granular lymphocyte (LGL) proliferation, we identified 10 patients (median age at diagnosis, 60 years; range, 35 to 76 years; male:female ratio, 3:2) with persistent (greater than 6 months) increase in phenotypically determined NK cells (CD3-CD16+). Southern blot analysis performed on 9 patients showed no clonal T-cell receptor gene rearrangements. Disease duration was measured from time of initial recognition of LGL or NK cell excess (greater than 40% of the lymphocyte fraction). Clinical data from these 10 patients were compared with those from 68 patients with T-cell LGL (T-LGL) leukemia. Currently, all patients are alive (median disease duration, 5 years; range, 0.8 to 8 years). Associated disease manifestations included pure red blood cell aplasia, recurrent neutropenia, recurrent neutropenic sepsis, and vasculitic syndromes, all of which were responsive to immunosuppressive therapy. No patient had palpable lymphadenopathy or splenomegaly. Compared with the patients with T-LGL leukemia, patients with chronic NK cell leukemia has similar lymphocyte counts, associated conditions, treatment responses, and survival but had less neutropenia and anemia.

Adrenal Cortex Hormones↗
PubMed1994

Risk of leukemia following treatment for non-Hodgkin's lymphoma.

BACKGROUND: There have been few evaluations of the risk of acute nonlymphocytic leukemia (ANLL) following therapy for non-Hodgkin's lymphoma (NHL). Further, the relationship between cumulative dose of cytotoxic drug, radiation dose to active bone marrow, and the risk of ANLL following NHL have not been well described. PURPOSE: Our purpose was to examine the risk of ANLL in relationship to all prior treatment for NHL. METHODS: Within a cohort study of 11,386 2-year survivors of NHL, 35 case patients with secondary ANLL were identified and matched to 140 controls with NHL who did not develop ANLL. The primary eligibility criteria for the cohort included a diagnosis of NHL as a first primary cancer from January 1, 1965, through December 31, 1989; age 18 through 70 years at the time of initial diagnosis; and survival for 2 or more years without the development of a second invasive primary malignancy. Detailed information on chemotherapeutic drugs and radiotherapy was collected for all patients. Standard conditional logistic regression programs were used to estimate the relative risk (RR) of ANLL associated with specific therapies by comparing the exposure histories of case patients with individually matched controls. RESULTS: Significant excesses of ANLL followed therapy with either prednimustine (RR = 13.4; 95% confidence interval [CI] = 1.1-156; P trend for dose < .05) or regimens containing mechlorethamine and procarbazine (RR = 12.6; 95% CI = 2.0-79; P < .05). Elevated risks of leukemia following therapy with chlorambucil were restricted to patients given cumulative doses of 1300 mg or more (RR = 6.5; 95% CI = 1.6-26; P < .05). Cyclophosphamide regimens were associated with a small, nonsignificant increased risk of ANLL (RR = 1.8;95% CI = 0.7-4.9), with most patients receiving relatively low cumulative doses (< 20,000 mg). Radiotherapy given at higher doses without alkylating agents was linked to a nonsignificant threefold risk of ANLL compared with lower dose radiation or no radiotherapy. CONCLUSIONS: Our results suggest that prednimustine may be a human carcinogen, with a positive dose-response gradient evident for ANLL risk. The low, nonsignificant risk of leukemia associated with cyclophosphamide was reassuring because this drug is commonly used today. Despite the excesses of ANLL associated with specific therapies, secondary leukemia remains a rare occurrence following NHL. Of 10,000 NHL patients treated for 6 months with selected regimens including low cumulative doses of cyclophosphamide and followed for 10 years, an excess of four leukemias might be expected.

Aged↗
PubMed1994

Clinical spectrum of clonal proliferations of T-large granular lymphocytes: a T-cell clonopathy of undetermined significance?

We identified 68 patients with clonal T-large granular lymphocyte (T-LGL) proliferations who were seen at the Mayo Clinic between 1984 and 1992. Nineteen (28%) were asymptomatic at diagnosis, while the rest experienced fatigue (60%), B-symptoms (12%), and recurrent infections (15%). Associated comorbid conditions included rheumatoid arthritis (RA) in 26%. Severe anemia (hemoglobin [Hb] < 8g/dL) and neutopenia (absolute neutrophil count [ANC] < 500/microL) were seen in 19% and 40% of patients, respectively. Immunophenotypic studies showed CD3+, CD8+ phenotype in the majority (72%). Twenty-one patients (31%) have required no therapy, and remain relatively stable with a median follow-up period of 50 months. Treatment was required at either diagnosis (36 patients) or at subsequent follow-up (11 patients). Initial response rates were similar in patients treated with cyclophosphamide (CTX) with or without prednisone (69%), or prednisone alone (73%). Overall, 61 patients (90%) are alive with a median follow-up of 44 months. Actuarial median survival of this entire cohort is 161 months. The presence of anemia or symptoms does not appear to correlate with the tumor burden. In patients requiring therapy, a lower ANC and the presence of B-symptoms/infection were independently associated with a significantly lower probability of achieving a molecular or hematologic complete remission (H-CR). Intermittent immunosuppressive therapy is effective in achieving durable responses in a number of patients. T-LGL proliferations are associated with a favorable prognosis and response to therapy. However, significant heterogeneity exists in clinical presentation and associated comorbid conditions. These disorders should be included in the differential diagnosis of patients with unexplained cytopenias, particularly in the setting of RA and other autoimmune disorders. Analogous to the situation with monoclonal gammopathies, a term such as T-cell clonopathy of undetermined significance (TCUS) may be more appropriate to describe these patients.

Adult↗
PubMed1994

The H(+)-ATPase from reticulocyte endosomes reconstituted into liposomes acts as an iron transporter.

The H(+)-ATPase from reticulocyte endosomes was purified and reconstituted into liposomes, and protein-dependent iron transport was observed. Reconstitution of the H(+)-ATPase into liposomes was performed by sonicating a lipid mixture, with a composition similar to the reticulocyte plasma membrane, in a buffer containing ferric citrate. The nonencapsulated iron:citrate was removed by gel filtration and the proteoliposomes diluted into 1 mM FerroZine. Upon addition of ascorbate, an initial efflux of 2.9 +/- 0.3 x 10(-2) mumol of iron/mg of ATPase/min and 56 +/-7% of total internal Fe(II) was detected by formation of the Fe(II)-FerroZine complex with an absorbance at 562 nm or radioactivity of 59Fe(II)-FerroZine following separation using gel filtration. Both thiosulfate and ferrocyanide could substitute for ascorbate. Citrate or EGTA could substitute for FerroZine. The initial rate of Fe(II) efflux was decreased by 41 or 17% using 100 microM of the cation channel inhibitor N,N'-dicyclohexylcarbodiimide or 70 microM of the ATP hydrolysis inhibitor N-ethylmaleimide, respectively, but was unaffected by the presence of ATP. The amount of iron transported was decreased 51 or 39% by 100 microM N,N'-dicyclohexylcarbodiimide or 70 microM of the ATPase inhibitor 7-chloro-4-nitrobenz-2-oxa-1,3-diazole. The amount of Fe(III) transport was 80% lower than Fe(II) when reductants were not present internally or externally although the apparent rate constants were identical when ascorbate was externally present. These results suggest that this vacuolar H(+)-ATPase may transport iron.

Animals↗
PubMed1994

Primary systemic amyloidosis presenting as giant cell arteritis and polymyalgia rheumatica.

Primary systemic amyloidosis may present with features suggesting a vasculitis, including giant cell arteritis (GCA) and polymyalgia rheumatica (PMR). In this report, we describe the clinical characteristics, temporal artery biopsy findings, and the response of vascular and musculoskeletal symptoms to corticosteroid therapy in 4 patients with primary systemic amyloidosis who presented with manifestations of GCA or PMR.

Aged↗
PubMed1994

A newly developed serum-free culture system: clonal growth of human acute myelogeneous leukemia (AML) progenitors--a report of 14 AML cases.

A new serum-free culture (SFC) system for human AML-CFU was established and the colony-promoting activity of four recombinant human hematopoietic growth factors (rhHGFs) including granulocyte-macrophage colony-stimulating factor (rhGM-CSF), interleukin-3 (rhIL-3), erythropoietin (rhEPO) and newly developed stem cell factor (rhSCF) were investigated in this SFC system. Under the orthogonal design condition, it was found that human AML-CFU presented optimal clonal growth in an environment of bovine serum albumin (0.6%), saturated human transferrin (2 x 10(-6) mol/L), cholesterol (2.8 micrograms/ml), bovine insulin (15 micrograms/ml), bovine hemin (0.05 mmol/L), linoleic acid (2.8 micrograms/ml), and IMDM. Spontaneously growing colonies were observed in 11 out of 14 cases studied. The plating efficiencies obtained by culturing with rhGM-CSF, rhIL-3, and rhSCF were 0.776 +/- 0.621%, 0.574 +/- 0.510%, and 0.647 +/- 0.543% (mean +/- s), respectively. There was one case (M3b) showing no response to all HGFs in both SFC ad SCC. The clonal growth of AML-CFU obtained from peripheral blood of the patient with M6 was unexpectedly marked. As a whole, the newly designed SFC system has been demonstrated to be useful for culture of human AML-CFU from both bone marrow and peripheral blood.

Culture Media, Serum-Free↗
PubMed1994

Extensive integration field beyond the classical receptive field of cat's striate cortical neurons--classification and tuning properties.

Length- and width-summation curves of striate cortex cells revealed that there exist facilitatory, inhibitory or disinhibitory integration fields (IF) beyond the sides and ends of the classical receptive field (RF). The extent of the IFs is most frequently 2-5 times the size of the RFs. The tuning properties of IFs were studied using an annular surround grating patch while an optimal centre patch was placed at the excitatory RF to continuously activate the cell. The results show that, for most cells, the orientation, spatial frequency and speed tuning of the IFs were similar to, but broader than, the tuning of the RF, whereas the direction selectivity of the IF was not as pronounced as that of the RF. The possible functional significance of the IF is discussed.

Animals↗
PubMed1994

Isolated bone marrow non-Hodgkin's lymphoma: a clinicopathologic study.

BACKGROUND: Isolated bone marrow non-Hodgkin's lymphoma (NHL) is rare, and determining the diagnosis is difficult. PATIENTS: We describe four patients with apparent isolated bone marrow NHL. The features they had in common included fever, abnormal liver function, pancytopenia, polyserositis, neurologic symptoms, opportunistic infections, and a short, fatal course. FINDINGS: Routine cytologic and histologic studies showed intermediate and large lymphomatous cells in the bone marrow, with a predominantly interstitial pattern. Immunophenotyping revealed three cases of T-cell and one case of B-cell NHL. Cytogenetic analysis demonstrated an abnormal clone in two patients. CONCLUSION: The diagnosis of isolated bone marrow NHL should be based on the examination of both bone marrow aspirates and biopsy specimens.

Adult↗