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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 1,243 records · Page 69Linked to original sources
PubMed1989

[Anesthesia problems in dental care in congenital epidermolysis bullosa. Illustration of a clinical case].

Congenital bullous pemphigus, because of successive episodes of erythema, serous or hematic vesicle formation and desquamation over the whole body including the oral cavity, causes severe problems for odontologists and anesthesiologists. The patient can only open his mouth partially and the fragility of the mucosa (development of bullae at the slightest touch of a dentist's instrument even if lubricated, during digital examination, etc.) makes intubation as well as surgical procedures very delicate propositions. The disease makes suturing of the oral mucosa impossible. These patients should receive regular dental care to avoid development of an advanced infection, knowing that the limitation of mouth opening only develops gradually as the disease progresses. Dermatologists should plan on monitoring and early routine care of teeth in any child with congenital bullous pemphigus.

Adolescent↗
PubMed1989

Expression of a retinoic acid receptor gene in myeloid leukemia cells.

Retinoic acid (RA) has been shown to increase differentiation in some leukemia cell lines (HL-60 and KG-1) but not others (K562). Similarly, RA has been reported to have variable effects on fresh blast cells. Recently, molecular clones have been obtained for the nuclear receptor for retinoic acid. The experiments described in this paper were designed to compare expression of the receptor to biological activity in myeloblastic leukemia cells. In four continuous AML cell lines, a positive correlation was found between retinoic acid receptor (RAR) expression by Northern analysis or RNA dot blot and the ability of RA to inhibit colony formation. Kinetic studies of the most sensitive cell line showed that inhibition of colony formation was associated with reduced blast cell self-renewal and differentiation-like events. RAR was detected in freshly obtained blast cells from 23 AML patients. Patient-to-patient variation was observed; however, a correlation was not found between RAR expression and response of the freshly obtained blast cells to RA.

Carrier Proteins↗
PubMed1989

Bf and C4 phenotypes in patients with psoriasis.

Phenotype frequencies for the complement proteins Bf (factor B), C4A and C4B were performed in a sample of 49 Caucasian patients with psoriasis followed in Memphis, Tennessee. The genes for these proteins are located in the major histocompatibility complex between the HLA-B and HLA-DR loci. Bf phenotype frequency did not differ significantly for the patients as compared to regional controls. The C4*A6 allele was present in 26.6% of the patients as compared to 5.4% of the controls, p less than 0.001, relative risk = 4.93. The C4*A6 allele is known to be in linkage disequilibrium with the HLA B17 allele and produces a functionally defective gene product. The role, if any, of C4*A6 in the pathogenesis of psoriasis is uncertain.

Complement C4↗
PubMed1989

[4 years' experience in the treatment of upper gastrointestinal strictures with balloon dilatation (analysis of 164 cases)].

One hundred and sixty-four cases of upper gastrointestinal strictures were treated with balloon dilatation in a period of 4 years. Totally 682 procedures were performed. Among them, sequential treatment and follow-up studies were done in 140 cases including anastomotic stricture 95, corrosive stricture of esophagus 33 and other kinds of stenosis of esophagus 12. The total effective rate was 90% (126/140) and long term effective rate 71.4% (100/140). Failure was observed in 14 cases (10%), of which 11 cases were due to tumor recurrence. In this paper the authors proposed the concept about short-term and long-term effect and criteria for evaluation; The factors influencing the effectiveness and the number of procedure undertaken are related to the cause and degree of stricture as well as the time selected for dilatation. The indications for such dilatation treatment are anastomotic stricture of upper gastrointestinal tract, esophageal web and corrosive stricture of esophagus. This method could be used as the treatment of choice, for cicatrical stricture of upper gastrointestinal tract of various causes.

Adolescent↗
PubMed1989

C4 and Bf phenotypes in black and Caucasian patients with childhood onset insulin dependent diabetes mellitus.

Certain alleles for the complement proteins, C4 and Bf, have been shown to be markers for insulin-dependent diabetes mellitus (IDDM) in samples of different racial and geographic composition. However, the same markers are not demonstrable in each group studied. Phenotyping for the complement alleles, C4 and Bf was performed on 168 Caucasian and 49 Black patients with IDDM. All of the patients were followed in Memphis, Tennessee and had onset of disease prior to age 18. The Bf*F1 allelic frequency was significantly increased for the Caucasian patients as compared to 93 healthy Caucasian controls (0.063 vs. 0.016) and for the Black IDDM patients as compared to 43 healthy Black controls (0.102 vs. 0.035). C4 phenotype frequencies showed a significant increase of the C4AQ0 (rr = 2.13) and C4A4 (rr = 2.91) phenotypes for the Caucasian IDDM patients as compared to controls, but the frequency of homozygous null C4A was not significantly increased. In addition significant negative associations of IDDM with C4A3 and C4A6 phenotypes and no association with any C4B phenotype were observed in our Caucasian patient population. Our data for Mild-South Blacks with IDDM suggest a similar positive association of IDDM with the BfF1 phenotype (rr = 3.4). However, there was no evidence among Black IDDM patients of the C4AQ0 and C4A4 associations observed in the Caucasian sample. The data support a possible association of IDDM with the C4A2 (rr = 5.86) and C4B2 (rr = 5.26) phenotypes. The hypothesis that racial admixture may account for the higher frequency of IDDM in US Blacks as compared with African Blacks has been forwarded by others.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1989

Growth factors influence the sensitivity of leukemic stem cells to cytosine arabinoside in culture.

We have proposed that the blasts in acute myeloblastic leukemia (AML) are renewal populations maintained by a small subpopulation of stem cells. The balance between self-renewal and differentiation in blast stem cells may be an important attribute contributing to treatment outcome. Cytosine arabinoside (ara-C) is included in most chemotherapeutic regimens for the treatment of AML. When ara-C survival curves are constructed, the drug appears to be more toxic when an assay is used that detects principally self-renewing divisions, compared with a procedure that depends on terminal divisions. AML blasts usually respond in culture to myelopoietic growth factors; their response often includes a change in self-renewal, differentiation, or both. These features of the model for AML blasts led to the prediction that growth factors would alter ara-C survival curves in a way that depended on the effects of the culture conditions on self-renewal and differentiation. Four AML blast populations were chosen to test this prediction on the basis of our ability to manipulate them by adding or withholding one or more growth factors. Highly significant changes were seen in the ara-C survival curves, depending on the growth factors present in the cultures as was predicted by the observed effects of the factors on renewal and differentiation.

Adult↗
PubMed1988

Rat skeletal muscle, liver and brain have different fetal and adult forms of the glucose transporter.

Rabbit antibodies made against the human erythrocyte glucose transporter were used to determine whether or not embryonic glucose transporters of rat skeletal muscle, liver and brain are identical to the transporters of adult animals. The results indicate that in both skeletal muscle and liver, the transporter switches from a highly antibody-reactive embryonic form to a low antibody-reactive adult form within 2 days of birth. This suggests that there are two different forms of glucose transporter in embryonic and adult skeletal muscle and liver. In contrast, these antibodies have equal reactivity toward the glucose transporters of embryonic and adult brain. In embryonic brain, two forms of the transporter coexist, with different molecular weights (Mr = 45,000 and 40,000), while in the adult brain the Mr = 40,000 form is predominant. The dissociation constant for glucose for the embryonic liver transporter was measured by displacement of bound cytochalasin B. The results indicate that the embryonic liver transporter has a low affinity for glucose and for cytochalasin B, similar to the adult liver transporter, even though the antibody reactivity toward these two transporters is different.

Animals↗
PubMed1988

Histopathology of traumatic corneal rupture after radial keratotomy.

Two patients (three eyes) had previously undergone technically successful radial keratotomy procedures and subsequently sustained blunt injury to the eyes in motor vehicle accidents one and two years after surgery, respectively, with rupture of the cornea along the keratotomy scars. One case subsequently required penetrating keratoplasty to recover 20/50 visual acuity. The second patient died, but had he survived, the extensive ocular injuries would have required significant surgical and medical care to restore vision. Histologic and ultrastructural studies demonstrated incomplete wound healing in the three corneas. Individuals who have had radial keratotomy, like those who have had penetrating keratoplasty, are at increased risk of corneal rupture after direct ocular trauma.

Accidents, Traffic↗
PubMed1988

The efficacy results and safety profile of imipenem/cilastatin from the clinical research trials.

Imipenem/cilastatin is highly effective for infections in many body sites against a broad range of gram-positive and gram-negative aerobic and anaerobic bacteria. During therapy, development of resistance is uncommon except in the case of Pseudomonas aeruginosa in which the incidence appears similar to that for other beta-lactam antibiotics. There appears to be a very low probability of cross-resistance. The clinical and laboratory adverse reactions are similar in type to those for other beta-lactam antibiotics. The frequency of colonization and superinfection during treatment with imipenem/cilastatin has been comparable to other antibiotics in comparative trials and to literature reports for other antibiotics for noncomparative trials.

Bacterial Infections↗
PubMed1988

The effects of recombinant CSF-1 on the blast cells of acute myeloblastic leukemia in suspension culture.

Recombinant hemopoietic colony-stimulating factors (CSFs), including GM-CSF, G-CSF and IL-3, have been shown to be effective stimulators of both self-renewal and terminal differentiation of blast stem cells in acute myeloblastic leukemia (AML). We have examined the activity of a fourth growth factor, recombinant CSF-1 (or M-CSF), on the growth of leukemic blasts in culture. CSF-1 was found to be active on some, but not all, blast populations. In sensitive cells, CSF-1 often stimulated the production of adherent blast cells incapable of division. This observation leads us to suggest that CSF-1 may be useful in the treatment of selected cases of AML.

Adult↗
PubMed1988

Expression of the CSF-1 gene in the blast cells of acute myeloblastic leukemia: association with reduced growth capacity.

Myelopoietic growth factors are known to influence the growth in culture of malignant blast cells from human Acute Myeloblastic Leukemia (AML). We have used cDNA clones for the factor CSF-1 and its receptor fms to study DNA and RNA from the blasts of 25 AML patients. The CSF-1 gene was always in the germline configuration. CSF-1 mRNA was found in about half the blast populations. The cells were also studied for their growth properties in culture. A highly significant association was found between CSF-1 expression and poor growth in suspension culture. Most blast populations expressed fms; the number of fms expression negative samples was to small to permit the detection of any association between fms expression and growth or any interaction between the effects of the expression of the growth factor and its receptor. We propose that CSF-1 may be an important part of the mechanism determining the balance between self-renewal and determination in AML blast clones.

Blast Crisis↗
PubMed1988

Follow-up of men in the recovery period immediately after the cessation of gossypol treatment.

Variables in 46 men who had stopped taking gossypol in two centres in China were investigated for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 x 10(6)/ml and 30.7 x 10(6), respectively. Twenty-eight (61%) recovered to a defined threshold spermatogenic function (sperm concentration greater than or equal to 20 x 10(6)/ml), with median recovery time 1.1 years. However, 18 men (39%) had not recovered after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.

Contraceptive Agents, Male↗
PubMed1988

Properties of NAD glycohydrolase purified from five-pace snake (Agkistrodon acutus) venom.

NAD glycohydrolase (NADase) (E.C. 3.2.2.5) from five-pace snake (Agkistrodon acutus) venom was purified to electrophoretic homogeneity through a 4-step isolation procedure, including column chromatography using DEAE-Sephadex A-50, Sephadex G-75, CM Sephadex C-50 and Sephadex G-100. The final product was 11.8-fold purified with a 3.9% yield. The pure enzyme showed maximal activity at about 40 degrees C with optimal pH at 7.5. It was a glycoprotein with a pI of 7.6. Its mol. wt was respectively 98,000 as measured by gel filtration and 50,000, by SDS-PAGE. There was only one N-terminal residue, proline. NADase is thus composed of two identical subunits in each molecule. The enzyme contained copper ions. NADase activity was lost when the copper enzyme complex was treated with EDTA. The Km of the enzyme for beta-NAD, NADP and beta-NGP were 0.50 mM, 0.13 mM and 0.16 mM respectively.

Animals↗
PubMed1988

Determination of DNA structures by NMR and distance geometry techniques: a computer simulation.

Computer simulations have been performed to determine how accurately and precisely structures of DNA oligomers can be generated from distance data obtained from two-dimensional NMR experiments. A hexamer fragment d(CGAATT) of the Dickerson dodecamer [Drew, H.R., Wing, R.M., Takano, T., Broka, C., Tanaha, S., Itakura, K. & Dickerson, R.E. (1981) Proc. Natl. Acad. Sci. USA 78, 2179-2183] was used as the model structure in these simulations. Protons were added to the coordinates of the original x-ray structure, which was then subjected to a regularization procedure to minimize deviations from standard bond lengths and bond angles. The proton-proton distances normally observed in NMR experiments were measured from this regularized target structure and used as input for a distance geometry algorithm. Distance geometry structures were generated from two distance sets, one with essentially exact distances (+/- 0.005 A) and one set with a precision (+/- 0.2 A) that simulates an optimal NMR experiment. The results of these calculations were used to judge how accurately and precisely the following helical parameters could be reproduced from this simulated NMR distance data: helical twist, helical rise, dislocation, roll, tilt, glycosidic angle, delta torsion angle, and pseudorotation angle. These data provide a basis from which to judge the quality of DNA structures produced from real NMR experiments.

Base Sequence↗