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Biomedical subjects

W C Wang

Publications and source records attributed to W C Wang.

At least 127 records · Page 7Linked to original sources

High risk of recurrent stroke after discontinuance of five to twelve years of transfusion therapy in patients with sickle cell disease.

Although long-term transfusion therapy is at least 90% effective in preventing recurrent strokes after an initial cerebrovascular accident in patients with sickle cell disease, it is unknown how long transfusion therapy should be continued. To address this question, we prospectively discontinued transfusions in 10 patients with sickle cell disease whose median duration of transfusion therapy after an initial stroke was 9 1/2 years (range 5 to 12 years). Before the transfusions were discontinued, patients were examined by cerebral angiography, magnetic resonance imaging of the head, neuropsychologic testing, electroencephalography, and a complete neurologic examination. Within 12 months after transfusion therapy was stopped, 5 of 10 patients had had an ischemic event. Three events caused relatively mild deficits in the same areas as those originally affected. Two were associated with massive intracranial hemorrhage, including one on the contralateral side of original involvement. An additional patient died suddenly of unknown causes. Of the four remaining patients, three declined to resume transfusion and are relatively well at greater than or equal to 18 months after therapy was stopped. The studies performed before transfusions were stopped were not predictive of recurrent stroke. The risk of recurrent cerebrovascular accident in this group was significantly greater than the estimated risk of 10% in patients who are receiving long-term transfusion therapy (p = 0.002). This adverse outcome suggests that patients with sickle cell disease who have had a stroke must receive long-term transfusion indefinitely or a suitable therapeutic alternative must be devised.

Adult↗

Nasopharyngeal carcinoma in young patients.

We have reviewed retrospectively the records of 157 patients, less than or equal to 30 years of age with nasopharyngeal carcinoma (NPC) from 218 such cases identified in the tumor registry files of three major teaching hospitals in Taipei, Taiwan. These cases were diagnosed between 1 January 1982 and 31 December 1985, with a minimum follow-up of 2 years. The average age was 25, with a male/female ratio of 1.67. The TNM (tumor size, nodes, metastases) classification of 127 patients showed T1, 22%; T2, 33.1%; T3, 23.6%; T4, 21.3%; N0, 26%; N1, 16.5%; N2, 27.6%; N3, 30%; and M1, 13.4%. Antibody titer to Epstein-Barr virus capsular antigen (EBVCA) were elevated in 45 of 48 patients tested. Of the 29 patients who had hepatitis B (HB) viral survey done 34.5% were positive for HB surface antigen (HBsAg). Of 13 patients with elevated EBVCA antibody who were also tested for HB, six were HBsAg carrier. Actuarial survival rates of 2 and 3 years are 70 and 62%, respectively, among the 90 patients who were followed regularly or to death. HBsAg carriers and patients with M1 disease had a shorter survival time. We concluded that patients less than 30 years of age seemed to have an increased incidence of NPC, compared to that in an earlier report. Our patients frequently presented with advanced stage and poor prognosis. The high rate of HB carrier raises the possibility that HBV may play a role in the carcinogenesis and tumor growth in some NPC patients. Future prospective studies are needed.

Adolescent↗

Granulocyte colony-stimulating factor corrects the neutropenia associated with glycogen storage disease type Ib.

A young woman with glycogen storage disease, type Ib, and chronic neutropenia had severe recurrent infections. In a life-threatening situation, treatment with granulocyte colony-stimulating factor (G-CSF) resulted in the prompt correction of neutropenia. Subsequently, daily G-CSF therapy has allowed the maintenance of a normal neutrophil count and marked clinical improvement over a period of 18 months. The spectrum of neutropenic conditions which are responsive to G-CSF should include this inherited metabolic disorder.

Adult↗

[Endocrine activity of pseudolaric acids A and B and their effects on sex hormones, prostaglandins, uteri, and fetuses].

Two novel diterpendoids, pseudolaric acids A and B (PA, PB) first isolated from the root of Pseudolarix kaempferi Gorden in China, have been reported to possess significant antifertile activities in rats, hamsters, rabbits, and dogs. The present study demonstrated that neither PA nor PB had estrogenic and antiestrogenic activities, they also did not inhibit deciduous formation. When an effective dose of PB 30 mg.kg-1 was given on d 6 of pregnancy and the hormonal determinations were done on d 8 and d 12 of pregnancy, the progesterone, estradiol and prostaglandins E, F levels in plasma and the uterine prostaglandin E, F levels were not significantly reduced vs those of the control rats. The human uterus was used as the experimental material in vitro. PA and PB 200 micrograms.ml-1 cultural medium (McCoy's 5a medium) damaged only a part of the decidual and trophoblast cells. In partially depolarized isolated uterine smooth muscles of early pregnant rats, PA and PB caused a decline in the contractile tension. A low dose of PB 2 mg.kg-1.d-1 was given ig on d 6-12 of pregnancy in rats caused the body weight and the length of fetuses and the placental weight value significantly lower than those of the control. Thus, ischemia due to the vasoconstrictor effect is probably of great, and sometimes of supreme, importance.

Abortifacient Agents, Nonsteroidal↗

[Antifertility effect of the implant containing 16-methylene-17 alpha-acetoxy-19-norprogesterone (ST-1435)].

The silastic capsules containing ST-1435 (0.5, 1, 2, 4, 6 or 8 mg) showed "burst effect" with a peak value of 4-15 micrograms.h-1 after incubation in vitro. A constant release rate was gradually approached within 1-2 wk. After the capsules were subcutaneous implanted or vaginally administrated, the rats manifested diestrus within 24-48 h. The normal estrus cycles and fertility were restored as soon as the release rate of implants decreased to 10 micrograms.d-1 in vitro. ST-1435 did not inhibit the superovulation induced by PMSG and HCG in immature female rats, but blocked the ovulation induced by LHRH in mature rats.

Animals↗

[Effects of pseudolaric acid B on blood flows of endometrium and myometrium in pregnant rats].

Effects of pseudolaric acid B (PB) on endo- and myo-metrial blood flows were measured by hydrogen gas clearance technique in 336 pentobarbital-anesthetized rats divided into control and 2 medicated groups (ig PB 20 and 30 mg.kg-1 on d 7-9 of pregnancy). Measurements of endo- and myo-metrial blood flows were done on d 7-14 of pregnancy. Results showed that the endo- and myo-metrial blood flows were reduced by 33-66% and 30-65% respectively, vs ig 1% CMC 0.5 ml (P less than 0.01). Uterine weight during d 10-14 of pregnancy stopped gain. The systemic arterial pressure remained relatively unchanged. It is concluded that PB causes a significant decrease of blood flow in both endo- and myometrium, which is accounted as the most important cause of embryo's death.

Abortifacient Agents, Nonsteroidal↗

The retinoic acid alpha receptor gene is frequently disrupted in its 5' part in Chinese patients with acute promyelocytic leukemia.

The t(15;17)(q22;q11-q21) translocation, a hallmark for acute promyelocytic leukemia (APL), has recently been shown to disrupt the retinoic acid-alpha receptor (RARA) gene localized on band 17q21. Leukemic cell DNAs from 16 Chinese patients with APL were analysed by Southern blot hybridization with probes covering the 5' and the 3' parts of the gene. In ten patients, the breakpoints were concentrated within a 5.5 kb EcoRI fragment containing part of intron 1, whereas no rearrangement was detected in the six remaining patients. Genomic amplification of the RARA gene was observed in one case. When RNA was available (six patients), abnormal-sized RARA gene transcripts were observed. Interestingly, no rearranged transcript was found in cells from a patient during a 6-day treatment with all-trans retinoic acid, while bone marrow cells still possessed the translocation.

Adolescent↗

Hemostasis in Glanzmann's thrombasthenia (GT): GT platelets interfere with the aggregation of normal platelets.

The transfusion requirements for a 6-year-old Glanzmann's thrombasthenia (GT) patient undergoing tonsillectomy and adenoidectomy were studied. Transfusion of pheresed platelets from a single normal donor increased the platelet count by 63 x 10(9)/L but did not correct the bleeding time. Since the ratio of normal:GT platelets in vivo was approximately 1:5, it was possible that GT platelets interfered with the function of normal platelets. To test this hypothesis, mixtures of platelet-rich plasma (PRP) from a normal donor and the patient were studied to determine a ratio of normal:GT platelets that would yield acceptable in vitro aggregation. Normal:GT ratios of 1:4 and 3:2 resulted in 25% and 59% aggregation, respectively. Mixtures of normal and nonfunctional ethylene glycol tetra-acetic acid-treated platelets gave similar results. Aggregates from mixtures of normal and patient platelets were also examined morphologically by light microscopy and were proportional in size to the normal:GT platelet ratio. Transfusion of platelets from the pheresis of four donors increased the patient's platelet count by greater than 300 x 10(9)/L (normal:GT ratio 1:1), produced 53% aggregation, and resulted in satisfactory postoperative hemostasis. The platelet transfusion requirement for this GT patient was much greater than would have been expected in the absence of aggregation-defective platelets.

Antibodies, Monoclonal↗

Granulocytic differentiation of HL-60 cells is associated with increase of poly-N-acetyllactosamine in Asn-linked oligosaccharides attached to human lysosomal membrane glycoproteins.

HL-60 cells were induced to differentiate into granulocytic cells by dimethyl sulfoxide, and structures of Asn-linked oligosaccharides attached to lysosomal membrane glycoproteins (lamp-1 and lamp-2) were elucidated before and after differentiation. Lamp-1 and lamp-2 were immunoprecipitated from the cells after labeling with radioactive sugars, and glycopeptides were prepared. The structures of glycopeptides obtained after serial lectin-affinity chromatography were elucidated by endo-beta-galactoside and methylation analysis. Glycopeptides bound to tomato lectin-Sepharose were found to be tetraantennary oligosaccharides that contain two or three poly-N-acetyllactosaminyl chains, of which one side chain contains three or more N-acetyllactosaminyl repeats, whereas those bound to Datura stramonium agglutinin-Sepharose were found to be tetraantennary oligosaccharides containing one or two short poly-N-acetyllactosaminyl side chains. Glycopeptides that were not bound to concanavalin A, tomato lectin, or D. stramonium agglutinin were found to be triantennary oligosaccharides with a negligible amount of poly-N-acetyllactosaminyl side chains. Comparison of Asn-linked oligosaccharides from undifferentiated and differentiated HL-60 cells reveals the following features. First, the number of Asn-linked oligosaccharides containing poly-N-acetyllactosaminyl side chains increases dramatically with a concomitant decrease in less complex Asn-linked oligosaccharides after differentiation. Second, the number of poly-N-acetyllactosaminyl side chains per Asn-linked oligosaccharides increases significantly. These increases in poly-N-acetyllactosamine were associated with increased activity of UDP-GlcNAc:beta-D-Gal-beta 1----3-N-acetylglucosaminyltransferase "extension enzyme," a key enzyme in the formation of poly-N-acetyllactosamines. Furthermore, the increased amount of poly-N-acetyllactosamine in lamp-1 and lamp-2 resulted in longer half-lives of lamp-1 and lamp-2 in differentiated HL-60 cells. These results suggest strongly that the differentiation of HL-60 cells into more phagocytic cells is associated with an increase in the complexity of Asn-linked oligosaccharides attached to lysosomal membrane glycoproteins, which in turn may play a role in stabilizing lysosomes.

Antigens, CD↗

Enzymatic cleavage of a CD4 immunoadhesin generates crystallizable, biologically active Fd-like fragments.

CD4, the cell-surface receptor for the human immunodeficiency virus (HIV), is a member of the immunoglobulin (Ig) gene superfamily. It contains four extracellular sequences homologous to Ig VL domains. The first of these (V1) is sufficient for binding to HIV; however, the structural basis for this binding has yet to be elucidated. While several models for the structure of Ig-like domains in CD4 have been proposed on the basis of crystal structures of Ig VL domains, direct evidence that CD4 and VL domains fold similarly has not been obtained. To produce individual domains of CD4 for structural studies, we used molecular fusions of such domains with Ig heavy chain (CD4 immunoadhesins), which are very efficiently expressed and secreted in mammalian cells and can be easily isolated in single-step purification with protein A. Since these fusion molecules are antibody-like homodimeric proteins, we investigated the possibility that they might be cleaved enzymatically to produce Fd-like and Fc fragments. We found that cleavage with papain releases an Fd-like fragment containing the V1 and V2 CD4 domains; this fragment fully retains the ability to bind to the HIV-1 envelope glycoprotein gp120 and to block HIV infection in vitro. Moreover, folding of the CD4 domains in the Fd-like fragment and in the parent immunoadhesin is indistinguishable, as indicated by circular dichroism. Spectral analysis of the Fd-like fragment suggests that secondary structure content is identical with that predicted from the known structure of Ig VL domains; this directly supports the hypothesis that the V1 and V2 domains of CD4 fold similarly to Ig VL domains.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

Relationship between hormone profiles and the restoration of spermatogenesis in men treated with gossypol.

Gossypol acetic acid was administered orally to 35 male volunteers at a dose of 20 mg once a day for 52-70 days in the loading phase and twice a week for 22 months in the maintenance phase. Sperm counts and the serum concentrations of LH, FSH, prolactin, testosterone and oestradiol were monitored regularly during treatment and for a follow-up period of 12 months. At around 90 days after treatment, all treated participants approached or attained azoospermia and remained at this level throughout the maintenance phase. By the end of the follow-up phase, eight treated men were still azoospermic, while sperm counts in the other 27 men were restored to normal levels. The only hormone that changed significantly during and after the treatment was FSH. From the 6th month of the treatment to the end of the follow-up phase, serum concentrations of FSH in the eight participants that reached irreversible azoospermia were significantly higher than in the other 27 men or in controls. It is suggested that monitoring of FSH levels might be of diagnostic use for identifying those participants with irreversible azoospermia during gossypol treatment.

Administration, Oral↗

Beneficial effect of brief pre-transfusion incubation of platelets at 37 degrees C.

The effects of brief warming of stored platelet concentrates were assessed in 15 children undergoing transfusion for stable thrombocytopenia due to chemotherapy (n = 13) or aplastic anaemia. Half of a pool of platelet concentrates stored at 22 degrees C was incubated at 37 degrees C for 1 hour and the other half at room temperature. Each patient received one bag of warmed and one of unwarmed cells transfused in random order 2 h apart. Platelet warming improved transfusion efficacy, as assessed on the basis of corrected platelet count increments (CCIs) and platelet morphology. Compared with unwarmed bags, warmed bags had a higher morphology score (p = 0.0001) and a higher CCI (adjusted for the transfusion order) at 1 h (n = 11; p = 0.014) and at 2 h (n = 15, p = 0.006) post transfusion. Thus, with platelets stored at room temperature bags warmed before transfusion to 37 degrees C for 1 h provide a larger number of circulating platelets after transfusion than do unwarmed bags.

Adolescent↗

Unusual chronic maculopapular rash associated with human immunodeficiency virus infection.

A 21-year-old black man with sickle cell disease who has received blood transfusions for 11 years because of recurrent stroke has had a decline in numbers of circulating lymphocytes and T4 cells over the past four years. Two and a half years ago persistent generalized lymphadenopathy developed, associated with a positive test for human immunodeficiency virus (HIV) antibody. For the past seven months he has had a pruritic maculopapular rash, primarily on the extensor surfaces of the extremities. Multiple skin biopsies revealed only nonspecific perivascular infiltrates of mononuclear cells. This rash appears to be an unusual manifestation of HIV infection, and may be an indicator of impending AIDS.

Adult↗

Immunological studies on thromboangiitis obliterans.

Using humoral immunity (gamma-globulin 18 cases, IgG, IgA, IgM each 30 cases, CH50, C3, C4 each 29 cases and CIC 31 cases), cellular immunity (E-RFC 68 cases, As 30 cases, SmIg, SmIgG each 18 cases, IMIT 30 cases) and immunopathological manifestations (light microscope, fluorescence microscope, transmitted electron microscope each 7 cases) as indices, we studied the immunological changes of "progressing", "remittent" and "stabilized" groups of patients with thromboangiitis obliterans (TAO) in different stages. Humoral immunity indicated that gamma-globulin, immune complex and IgG were all increased; cellular immunity indicated that the rate of T cells and suppressor cells was declined, while that of B cells was elevated. Immunopathologically, under light microscope all the layers of involved vessels were infiltrated with neutrophils, lymphocytes and monocytes; under fluorescence and electron microscope, immune complexes were found in the involved vessel walls. Our preliminary results suggest that TAO is an autoimmune disease relevant to antigen-antibody complex.

Adult↗

Distribution of juxtaglomerular cells and synthesis and release of renin granules in patients with renal artery stenosis.

100 pieces of renal tissue from 4 patients with renal artery stenosis were studied histologically. Juxtaglomerular cells were found not only in the region close to the glomerulus but also in the proximal 2/3 of the afferent arteriole of the glomerulus, but not in the interlobular arterioles. In the cytoplasm of juxtaglomerular cells, three kinds of granules were found: crystalline granules (immature), the round or ovoid granules (mature), and the lobulated granules (fusion). Renin was synthesized in the rough endoplasmic reticulum and packaged in the Golgi complex. Electron microscopic findings suggested that the secretory microvesicles were produced on the surface of Golgi complex. They fused to form primary crystalline granules, which were enlarged by renin supplied by transportation vesicles and finally formed typical crystalline granules. The mature renin granules (round or ovoid) moved toward the periphery of the cytoplasma. Their limiting membranes on the side toward the basement membrane disintegrated and formed microvesicular bodies passing through the periplasm, and the basement membrane and were discharged into the interstitial matrix.

Humans↗