Biomedical subjects
Publications and source records attributed to L Liang.
Three compounds were isolated from the leaves of Luffa cylinderica Roem. Their structure have been identified as 21 beta-hydroxy-gypsogenin (L-2), 3-O-beta-D-glucopyranosyl-arjunolic acid (L-8) and 3-O-beta-D-glucopyranosyl-21-beta-hydroxyhederangenin (L-10), respectively, by spectroscopic (IR, 1HNMR, 13CNMR, EI-MS and FAB-MS) and chemical methods. L-2 and L-10 are new compounds.
Recently, methods of reinnervating posterior cricoarytenoid muscle (PCA) have been reported by many authors. This study was undertaken to compare direct implantation (NI) of a branch of the ansa cervicalis supplying the sternothyroid muscle with the transfer of a neuro-muscular pedicle of the ansa cervicalis innervating the sternothyroid muscle (NMP) in a denervated PCA dog model. Both were carried out immediately after denervation. The results showed that reinnervation with return of physiological function of PCA were got by both methods of nerve transfer. The NMP was apparently superior to the NI. The reason was that the NMP implanted more motor end-plates into the denervated PCA. So the NMP should be chosen first when possible. The NI is consistently effective when NMP is not available.
The serodiagnosis of tuberculosis was evaluated by means of enzyme-linked immunosorbent assay of IgG antibody to mycobacterial antigen 60. The study population consisted of 63 patients with active tuberculosis comprising 43 pulmonary tuberculosis, 15 tuberculosis pleurisy, four miliary tuberculosis, and one tuberculous lymphadenitis. The control group consisted of 48 patients embracing 8 cases of inactive pulmonary tuberculosis, 31 cases of pulmonary disorders other than tuberculosis, and nine normal persons. There was a significant difference in antibody titers of sera between patients of active tuberculosis and control group (P < 0.001). The sensitivity of the test for active pulmonary tuberculosis was 81.4% and the specificity was 85.4% (cutoff value 300 units). The sensitivity for all active tuberculosis was 61.9%. There was positive correlation between serum titer of active pulmonary tuberculosis and the extent of disease on chest radiography (r = 0.4, P < 0.01). A positive correlation was found between the titers of pleural fluids, and the corresponding sera in 15 patients (eleven tuberculous pleurisy and four nontuberculous controls) (r = 0.85, P < 0.001). Whether serum or pleural fluid, the positive rate of the assay for tuberculous pleurisy was relatively low. In conclusion, the A60 IgG ELISA test may be useful in serodiagnosis of pulmonary tuberculosis and assessment of the disease extent, although it might not yield a high sensitivity for tuberculous pleurisy.
The oncogenic E7 proteins of human papilloma virus (HPV 16) and of cottontail rabbit papilloma virus (CRPV) have been purified from an expression system in Escherichia coli. The proteins as purified from E. coli contain one tightly bound Zn(II) ion per molecule. The metal site shows facile exchange with either Cd(II) or Cu(I). The HPV 16 E7 maximally bound one Cd(II) or two Cu(I) ions, while the CRPV E7 bound two Cd(II) or three Cu(I) ions. The Cd(II) and Cu(I) E7 molecules exhibited optical transitions in the ultraviolet suggestive of metal:thiolate coordination. E7 proteins from HPV 16 and CRPV contain 7 and 8 cysteines/molecule, respectively. Reaction of the E7 proteins with the sulfhydryl reagent, dithiodipyridine, revealed that all the cysteinyl sulfurs are present in the reduced thiol state. Cu(I)-E7 molecules are luminescent with maximal emission at 570 nm. The observed emission at room temperature is indicative of metal coordination within a compact protein environment shielded from solvent interactions. The emission maxima occurs at the same wavelength (570 nm) as Cu(I)-cysteinyl sulfur clusters in Cu(I)-metallothioneins. The single Zn(II) atom in each protein can be removed from E7 in the presence of EDTA. The resulting apoE7 molecules remain soluble and can be partially reconstituted with Cd(II) to regain the ultraviolet charge transfer transitions.
Comparisons of the site specific binding of nitrobenzylthioinosine (NBMPR) to intact and lysed red cells from various mammalian and avian species suggest the presence of a cytoplasmic pool of nucleoside transporters. In some species the cytoplasmic pool is about 50% of the total (mouse). On the average, the cytoplasmic pool is approx. 20% of the surface pool of NBMPR-binding sites. In sheep reticulocytes, both pools disappear in an energy-dependent manner during the maturation of the reticulocyte in vitro.
The generation of memory B cells in response to vaccination with a baculovirus-derived recombinant gp160 candidate AIDS vaccine, VaxSyn HIV-1, was investigated in 12 healthy human volunteers who were immunized with VaxSyn HIV-1, hepatitis B vaccine, or alum adjuvant alone on days 1, 28, 180, and 540. Peripheral blood mononuclear cells were collected pre- and post-immunization and cultured unstimulated or with pokeweed mitogen (PWM), VaxSyn HIV-1 (rgp160), or HIV-1 lysate (iHIV-1) for 7 days before polyclonal and HIV-1-specific IgG production in culture supernatants (SNs) were measured. No differences were seen in the spontaneous or PWM-induced IgG production in SN from vaccinees and controls. Only vaccinee SN contained higher-than-normal levels of polyclonal IgG after stimulation with either rgp160 or iHIV-1, especially after the second and third booster immunizations on days 180 and 540, respectively. There were also contemporaneous increases in HIV-1-specific antibody in SN of all vaccinees, albeit at different time points throughout the study. We conclude that VaxSyn HIV-1 induces antigen-specific B-cell responses with the generation of memory B cells in vivo that can be reactivated in vitro to deliver an anamnestic response.
A method was developed for the determination of gadolinium (Gd) in biological material using graphite furnace atomic absorption spectrometry (GFAAS). The element is first extracted into methyl isobutyl ketone and then reextracted into hydrochloric acid. Factors influencing the recovery of extraction such as pH, choice of chelating agents, and hydrochloric acid concentration have been investigated. The element is determined under STPF (stabilized temperature platform furnace) conditions with atomization from a tantalum boat. Under optimized furnace conditions, the use of the tantalum boat improved sensitivity substantially compared to the use of pyrolytically coated graphite tubes. Around 150 measurements could be performed with 1 boat. Memory effects, being a common problem in the GFAAS determination of lanthanoids, were no longer observed after insertion of the boat. The characteristic mass and detection limit (2SD; SD = standard deviation) of the Gd determination are 1000 and 2060 pg, respectively. The precision evaluated as the relative standard deviation (RSD) of six analyses was below 10% for tissue Gd concentrations ranging from 0.92 to 72.0 micrograms g-1. The recovery of added analyte ranged between 92.0% and 99.3%. The method was found to be suitable for studying the pharmacokinetics and biodistribution of Gd in rats.
Direct measurement of lead and cadmium in blood and urine by electrothermal atomic absorption spectrometry with deuterium background correction (D2-AAS) is prone to severe matrix and spectral interferences. We overcame these effects by coating the L'vov platform with ammonium molybdate, reducing the atomization time, introducing a post-atomization cooling step, carefully selecting ashing and atomization temperatures, and using an appropriate procedure for matrix modification. To determine Pb and Cd in blood and urine, we used matrix-matched calibration curves. With the proposed procedure for sample preparation, both Pb and Cd in whole blood can be determined in the same diluted sample. Results obtained by D2-AAS correlate closely with those by Zeeman-corrected AAS. Detection limits (mean blank + 3 SDblank) for Pb in urine and blood were 4 micrograms/L. For cadmium, the detection limits were 0.4 and 0.1 micrograms/L for urine and blood analysis, respectively. Between-run CVs were less than 5.0%.
As an animal model of human Parkinson's disease 250 micrograms of 6-Hydroxydopamine was injected intraventricularly in the rats. At 24 h, 48 h, 7th and 14th day after injection, the levels of dopamine, norepinephrine, Cu, Zn- and Mn- superoxide dismutase (SOD), catalase as well as the lipid peroxidative products in the striatum, midbrain and hypothalamus were determined. Our data showed that catecholamines decreased persistently, catalase and Mn-SOD decreased concomitantly, Cu, Zn-SOD, however, remained, unchanged. Lipid peroxidative products increased shortly after injection, then subsided. Our result suggests that lipid peroxidation might be involved in the degenerative process of neurons in Parkinson's disease.
We describe a direct-calibration method for determining aluminum in bone and soft tissues by graphite furnace atomic absorption spectrometry. Aluminum in bone was determined in uncoated tubes, whereas the analytical performance in soft tissue analysis was markedly improved by using pyrolytically coated tubes with a L'vov platform and added calcium. The analytical imprecision (CV) was less than or equal to 5.4% for aluminium concentrations between 12 and 98 micrograms/L, and analytical recoveries of added analyte varied between 94.5% and 103.0%. Detection limits (2 SD of determinations of the zero standard) were 7 and 6 pg for bone and soft tissues, respectively. Characteristic masses (amounts of Al yielding an absorbance signal of 0.0044 A) were 9 and 8 pg, respectively.
A tartrate-resistant acid phosphatase (TrACP), which has been suggested to be very similar to the osteoclastic TrACP, was partially purified from the spleen of a patient with hairy cell leukemia. The purification procedure consisted of carboxymethyl-Sepharose, phosphocellulose, Sephacryl S-200, and phenyl-Sepharose chromatographies. Polyclonal antibodies were generated in guinea pigs with a titer of at least 1:6000. Immunohistochemical staining of fetal rat tibia with the antisera revealed that only the lysosomes of osteoclasts, but not osteoblasts, were stained. An enzyme-linked immunosorbent assay (ELISA) was developed with the antisera. There was no cross-reactivity with 1) partially purified acid phosphatases (ACPs) from normal human and beef spleens, 2) ACPs in extracts of human osteoblastic cells, 3) purified bovine bone matrix TrACP, or 4) commercial prostatic ACP. However, extracts of giant cell bone tumors, containing large amounts of bona fide osteoclasts, showed large amounts of cross-reactive material, which diluted in parallel with the partially purified hairy cell leukemic TrACP in the ELISA. Commercial serum band 5b TrACP also displaced in parallel with the partially purified hairy cell leukemic TrACP. Immunoblotting studies revealed that the antiserum, but not nonimmune guinea pig serum, reacted with the homogeneous hairy cell leukemia splenic band 5 TrACPs, which were recently purified by our laboratory. Preliminary application of the ELISA to sera of patients with metabolic bone diseases revealed that normal healthy individuals had measurable amounts of the immunoreactive material, and patients with Paget's disease or hyperparathyroidism, who should have high bone turnover, had elevated levels of this immunoreactive material in their sera. In contrast, the level of serum osteoclastic TrACP in a patient with an acute lymphatic leukemia was normal. In summary, 1) we have shown that hairy cell leukemia splenic TrACP shares significant immunological similarity with the osteoclastic TrACP and with the serum band 5b TrACP, and 2) the ELISA holds promise for a sensitive and specific assay for bone resorption.
Gray-scale real-time ultrasound has been employed to investigate gallstone with a positive result of 553 cases out of 15,856 healthy subjects in city and countryside, the incidence being 34.88%. The feature of incidence is as follows: 1. The incidence of the simple gallbladder stone is more common than that of the other sites (male is about 81.15%, female is about 87.29%); 2. The incidence of gallstones of city residents is higher than that of the country people with significant difference statistically (P less than 0.01); 3. The incidence of gallstone in female city residents is higher than male, about 2.5:1, which shows significant difference. (P less than 0.01); 4. The incidence of gallstones in female city residents is higher than in countryside (P less than 0.01); 5. There is no significant difference in the incidence of gallstone between male and female in the countryside (P greater than 0.05); 6. There is no significant difference in the incidence of gallstones between city male and the male in the countryside (P greater than 0.05); 7. Either in the city or in the countryside, it has been shown that there is a tendency of increasing incidence of gallstone with age in both sexes (P less than 0.01). The relationship between the gallstone and the clinical symptoms has been discussed in this paper.
In attempting to study the phototherapeutic action and the photosensitized oxygenation mechanism, we have determined the crystal structure of the main oxidized product of hypocrellin A (HA). It was crystallized in monoclinic system with space group P2(1). The cell data are: a = 10.030(3), b = 8.877(3), c = 15.764(5)A, beta = 104.50(2) degrees, Z = 2. The crystal structure has been determined by direct method and refined to a final R of 0.055 based on the 1408 observed reflections with I greater than 2.5 sigma (I). The photooxidized product is composed of a heptacyclic aliphatic hydrocarbon connecting with two alpha-naphthoquinone derivatives as its skeletal molecule. No peroxidic linkage has been found. On the basis of the crystal structure determined, we have deduced part of the process of formation of the oxide, i. e. firstly, the peroxide was formed by photocycloaddition of oxygen molecule to Hypocrellin A, then thermodissociation took place to form a stable oxide.
The expression of heparan sulfate proteoglycans (HSPGs) by human glioma cells was examined by biochemical and immunological methods in vitro and in vivo. Chondroitin sulfate was shown to represent the major [3H]glucosamine-labeled glycosaminoglycan synthesized by cultured normal brain cells. However, high-grade glioma-derived cells were shown to express significantly increased quantities of hyaluronic acid and heparan sulfate and approximately equal amounts of chondroitin sulfate compared with normal glial cells. To investigate further the differential expression of HSPGs, proteoglycans were isolated from glioma cells and were used as an immunogen to generate monoclonal antibodies (MAbs). One of these MAbs, 39H (an IgM), was shown to bind more to high-grade glioma-derived cells then to low-grade glioma or normal brain cells in vitro. MAb 39H was also observed to bind to isolated HSPGs but not to heparan sulfate glycosaminoglycan chains or trypsin-treated cells. Immunofluorescence staining of the cultured high-grade glioma cells revealed an intense diffuse cell surface staining pattern over the entire cell and also isolated footpads. In contrast, the low-grade tumor or normal glial cells showed a distinctive punctated staining. A similar differential staining of MAb 39H was most prominent between tissue sections of glioblastoma multiforme and anaplastic astrocytomas versus low-grade astrocytomas and normal brain. The low grade gliomas exhibited a weak punctated staining, whereas the high-grade gliomas showed significantly more intense staining, particularly along the apical regions of the cells. These results suggest that altered expression of HSPGs may be related to the malignant transformation or growth potential of glial-derived cells.
A simple, rapid and low-cost method for the routine determination of iron in urine and serum using graphite furnace atomic absorption spectrometry is described which may provide an alternative to the more widespread automated spectrophotometric methods. The urine and serum samples were simply diluted with water prior to analysis. Matrix modification was found to be redundant. The standard additions technique or the use of matrix matched standards (addition calibration) was found to be unnecessary and, therefore, the calibration was performed using aqueous standards. For serum analysis the degree of dilution could be reduced by using the less sensitive 302.0-nm resonance line, yielding more precise determinations, and for urine analysis, interferences were eliminated by means of a L'vov platform. The interferences that exist in the presence of nitric acid are also discussed. Finally, the presence of background absorption was investigated by means of Zeeman effect atomic absorption.
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The influence of shapes of the bottom of culturing wells on lymphocyte proliferation was investigated. The lymphocytes were separated from the peripheral blood of eight donors by Ficoll-Hypaque density gradient centrifugation. Cells at 5 X 10(5)/ml were incubated in the absence, or in the presence, of PHA or Con A. The degrees of proliferation were compared in cultures using wells with variously shaped bottoms--flat, round and conical. The cultures in wells of flat bottoms provided the lowest background and highest mitogen-induced cell proliferation, whereas those in conical bottoms caused highest background and lowest mitogen-induced cell proliferation among the 3 types of bottom shapes. The peak proliferation in the presence of mitogen was at the end of the 3rd day in both round and conical bottoms, and at the end of the 4th day or later in flat bottoms.