Suppression of human nasopharyngeal carcinoma cell growth in nude mice by the wild-type p53 gene

Wild-type and mutant human p53 genes were transfected into the nasopharyngeal carcinoma (NPC) cell line CNE-3. Tumorigenicity in nude mice showed that the tumor resulting from the cells transfected with the wild-type p53 gene grew more slowly and was smaller than that from the cells transfected with mutant p53 gene and that from control CNE-3 cells. In contrast, the tumor from the cells transfected with the mutant p53 gene grew faster than that produced by cells transfected with the wild-type p53 gene and that produced by control CNE-3 cells. The results demonstrate that the wild-type p53 gene could inhibit the NPC cell growth in nude mice and the mutant p53 gene could enhance the NPC cell growth in nude mice. The p53 gene may also play an important role in the pathogenesis of NPC.

Iohexol cervical myelography in adult outpatients

The incidence of adverse reactions following standard film or screen cervical myelography with iohexol in 32 adult outpatients was reported. Iohexol at a dose of 1,080-3,000 mg of iodine was administered via a lateral C1-C2 approach in 26 patients and via a lumbar route in 6 patients. All 32 patients underwent postmyelographic cervical spine computed tomography and were discharged after the procedure was completed. No adverse reactions occurred in 53.1% of patients. The most common adverse reaction was headache (31.3%); other minor adverse reactions included exacerbation of pre-existing pain (12.5%), neck stiffness (9.4%), and vomiting (6.3%). Good to excellent technical quality was seen on all myelograms and computed tomographic scans. Outpatient cervical myelography with iohexol appears to be a safe and cost-effective alternative to inpatient examination.

Plasma membrane receptors for ecotropic murine retroviruses require a limiting accessory factor

A retroviral vector was used to express various amounts of the receptor (ecoR) for ecotropic host range murine retroviruses on naturally barren hamster, mink, and human cells. These cells and murine cells were then incubated for 2 h with dilutions of a helper-free ecotropic retrovirus that encodes human growth hormone, and the number of infected cells was later determined by growth hormone-specific immunofluorescence. For all cells under the conditions of these studies, virus adsorption was the limiting step of infection and the cellular capacities for infection were unsaturated either at cell surfaces or at intracellular sites. Thus, infections occurred at low multiplicities of infection per cell and were directly proportional to virus and cell concentrations, and only a small percentage (ca. 5%) of the infectious virions became adsorbed from the medium during the 2-h incubations. Although increasing the adsorption by raising virus or cell concentrations results in more infections in the cultures, increasing adsorption by raising the number of ecoR above a low threshold had no effect on infections. Thus, cells with a low number of ecoR were infected as efficiently as highly adsorbing cells that contained many times more ecoR. To reconcile these results, we conclude that only a small, set number of cell surface ecoR can be functional for infection and that all excess ecoR can only bind virus into an unsalvageable pool. Therefore, retroviral receptors on single cells are functionally diverse. Our results suggest that activity of ecoR in infection requires a limiting second cellular component.

Developmental expression, compartmentalization, and possible role in excitotoxicity of a putative NMDA receptor protein in cultured hippocampal neurons

The mechanisms regulating the expression and localization of excitatory amino acid (EAA) neurotransmitter receptors in neurons of the developing mammalian brain, and roles for these receptors in the plasticity and degeneration of neural circuits are not well understood. We previously isolated and characterized a 71 kDa glutamate binding protein (GBP) from rat brain, and have recently obtained evidence that this GBP is a component of a functional N-methyl-D-aspartate (NMDA) receptor-ion channel complex. We have now used antibodies to this putative NMDA receptor protein to examine its expression and localization, and consequences of its activation in cultured embryonic (18 day) rat hippocampal neurons. Immunocytochemistry and Western blots using monoclonal antibodies to the GBP demonstrated an increase in GBP-positive neurons and their staining intensity with time in culture. GBP was localized to the somata and dendrites of pyramidal-like neurons and was sparse or absent in the axons. The expression and compartmentalization of GBP occurred in isolated neurons indicating that direct cell interactions were not required for these processes. Cell surface staining for GBP occurred in patches on the soma and dendrites. The developmental expression of GBP immunoreactivity closely paralleled the expression of sensitivity to NMDA neurotoxicity. There was a direct relationship between GBP immunoreactivity and neuronal vulnerability to glutamate-induced degeneration; vulnerable neurons stained heavily whereas resistant neurons showed either low levels of staining or no staining. Finally, a GBP antiserum greatly reduced NMDA neurotoxicity (but not kainate neurotoxicity). Taken together, these findings demonstrate the expression of presumptive NMDA receptors within a subpopulation of embryonic hippocampal neurons, and their segregation to the soma and dentrites of pyramidal neurons. This spatial distribution of glutamate receptors among and within neurons is likely to play important roles in regulating the structure of neural circuitry during development, and may also be an important determinant of selective neuronal vulnerability in pathological conditions.

[Changes in plasma coagulant factors and plasma fibrinolytic activity in patients with viral hepatitis]

16 coagulant and 7 fibrinolytic parameters were determined in 121 normal subjects and 456 patients with various types of viral hepatitis. The results showed that plasma concentration of F VIII: c, vWF: Ag and vWF: Ag/VIII: c (P less than 0.01) were much higher than those in the controls. Plasma level of other coagulant factors was progressively reduced when the severity of hepatitis was decreased. The changes of fibrinolytic activity suggest that t-PA, PL and FDP were increased, while PAI, PLG, and alpha-PI were decreased. The results of this study may provide an experimental basis for further study of hemorrhage mechanism and prognosis in patients with viral hepatitis.

Influences of Polyactin A on activities of human monocytes in vitro

Effects of Polyactin A (PAA) on abilities of human monocytes to synthesize and secrete interleukin-1 (IL-1) and to modulate natural killer (NK) cell activity in large granular lymphocytes (LGL) were investigated in vitro. Over a wide range of concentrations (0.01-100 micrograms.ml-1), PAA directly induced IL-1 synthesis and secretion, showing the maximal effect at 10 micrograms.ml-1, and evidently synergized with lipopolysaccharides (LPS) of E coli in stimulation of IL-1 production by human monocytes. The manifestation of PAA pretreated autologous monocytes in modulation of NK cell activity was closely related to PAA concentration. A boosting effect of PAA-treated monocytes on NK activity was observed when PAA 10-100 micrograms.ml-1 were used for pretreatment of monocytes, while an inhibitory influence of monocytes was found when PAA 0.01-0.1 microgram.ml-1 were used. These results demonstrate significant effects of PAA on functions of human monocytes, enhancing IL-1 production and affecting their regulative activity on NK cell cytotoxicity.

Preparation and certification of lyophilized human urine for trace metals reference material in China

The preparation of lyophilized human urine certified reference material (CRM) was established on the basis of literature in other countries and domestic conditions. The homogeneity and stability of the CRM accord with the stipulations. The certified values were determined by 14 high level laboratories in China using nine methods with different principles and have been examined by the National Institute for Occupational Safety and Health (NIOSH) using Inductively Coupled Plasma--Mass Spectrometry (ICP-MS). This CRM has been approved as first grade national reference material. It can be used in quality control of routine analysis, test of new methods, and as standard material for calibration of analytical instruments and as certified reference material for quantity transmission and analysis arbitration.

Okadaic acid interferes with lipoprotein-supported corticosterone production in adrenal cells

Rat adrenocortical cells in culture respond to stimulation by ACTH alone (15 fold over basal) and to ACTH + added lipoproteins (as an exogeneous source of cholesterol), with an additional 25-30 fold rise in steroidogenesis. With the addition of okadaic acid (OKA, 100 nM), a potent protein phosphatase inhibitor, the lipoprotein-induced rise in steroidogenesis is blocked. If 20 alpha-hydroxycholesterol is provided instead of lipoprotein-cholesterol, OKA has no effect suggesting that OKA affects only actively transported cholesterol. Since the OKA block is preceded by specific morphological changes in the cell (i.e., the loss of Golgi-associated microtubules followed by the disruption of the Golgi apparatus itself), it is hypothesized that some OKA-sensitive phosphoprotein associated with the microtubule/Golgi network of adrenocortical cells is critical for lipoprotein-derived cholesterol uptake and/or transport during steroidogenesis.

[Preliminary study of cervicovaginal peroxidase as indicator for ovulation]

The study was designed to determine whether the change in the pattern of cervicovaginal peroxidase activity in the fertile period of women can serve as a basis for the development of a technique to predict ovulation time in natural family planning. Eight healthy women volunteered for this study in Chengdu area. The samples of cervical mucus and vaginal secretion were collected. The specific G-Px activity was measured with reference to the procedure of Tsibris, et al., on days 6, 8, 10, 12 through 16, 18, 20, 22, 24 of each menstrual cycle; at the same time an antecubital venous blood sample was drawn to be analyzed for levels of LH, FSH, E2, and P by RIA. The data showed that in 7 ovulatory cycles the G-Px activity did not vary regularly in vaginal secretion but it did drop rapidly in cervical mucus 2 or 3 days before ovulation time and it rose again one day after ovulation. The results suggest that the measurement of the G-Px activity in cervical mucus can be used to predict ovulation by two to three days before the time.

Cell-surface receptor for ecotropic murine retroviruses is a basic amino-acid transporter

The complementary DNA sequence encoding the cell-surface receptor for ecotropic host-range murine retroviruses (ecoR) shows that it contains 622 amino acids and 14 hydrophobic potentially membrane-spanning sequences. Because this receptor occurs on many or all murine cells and is probably essential for viability of cultured fibroblasts, its normal function might be to transport an essential metabolite. We expressed ecoR in Xenopus laevis oocytes by injecting RNA transcribed from the cloned cDNA. These oocytes specifically bound the gp70 envelope glycoprotein from an ecotropic murine leukaemia virus. An inward current was recorded electrophysiologically when a mixture of amino-acids was applied: this resulted from a stereoselective, saturable uptake of lysine, arginine and ornithine; it was independent of sodium and not substantially altered by gp70. Cysteine and homoserine were also taken up, but sodium was necessary for their transport. These properties of ecoR correspond to those of the y+ amino-acid transporter. Our results demonstrate the subversion of a ubiquitous cell membrane protein, in this case a basic amino acid transporter, for use as a retroviral receptor.

Application of gadolinium-DTPA magnetic resonance imaging for detection of a filum terminale myxopapillary ependymoma allowing successful surgical resection

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Multiple luteinizing hormone/chorionic gonadotropin receptor messenger ribonucleic acid transcripts

It has previously been shown that multiple messenger RNA (mRNA) species can be identified in gonadal tissues by probes specific for the LH/CG receptor. Here we show that the sizes and relative abundancies of gonadal LH/CG receptor transcripts are quite variable between such closely related species as rat and mouse. These patterns of LH/CG receptor mRNAs are yet different from that observed in human embryonic kidney 293 cells that have been transfected with a cDNA encoding for the rat luteal LH/CG receptor. In spite of the diversity in the number and sizes of LH/CG receptor mRNA transcripts, however, our data also show that the size of the cell surface receptor expressed in these three cells/tissues is identical. We further show that the most abundant LH/CG receptor mRNA present in MA-10 cells, a clonal strain of cultured Leydig tumor cells, is a 1.2 kilobase transcript which encodes for a truncated version of the LH/CG receptor corresponding to the extracellular hormone-binding domain. It does not appear, however, that this transcript is translated into a functional protein.

Characterization and distribution of [3H]ohmefentanyl binding sites in the human brain

Binding properties and localization of [3H]ohmefentanyl, a new ligand for mu opioid receptors, were investigated on normal human brain sections. Binding assays performed at the level of the basal ganglia revealed: (1) a steady-state binding reached after 60 min incubation at room temperature, (2) the presence, in saturation experiments, of an apparent single class of binding sites with a Kd = 1.68 +/- 0.45 nM and a Bmax = 162 +/- 9 fmol/mg protein, (3) an order of potency to inhibit [3H]ohmefentanyl binding as follows: ohmefentanyl greater than [D-Ala2, MePhe4, Gly-ol5] enkephalin (DAGO) greater than ethylketocyclazocine (EKC) much greater than Tyr-D-Ser(OtBu)-Gly-Phe-Leu-Thr(OtBu) (BUBU) and U-50,488H. Quantitative autoradiography showed an heterogeneous distribution of [3H]ohmefentanyl binding sites with the highest densities in amygdala, medical geniculate body, thalamus, and caudate nucleus. Binding characteristics and anatomical distribution also show that [3H]ohmefentanyl may bind to a small proportion of additional sites called "DAGO-inaccessible [3H]ohmefentanyl specific binding sites." [3H]Ohmefentanyl binding to these sites can be partly inhibited by sigma ligands such as 1,3-di-o-tolylguanidine (DTG) and haloperidol. However, unlabeled DAGO inhibited more than 80% of [3H]ohmefentanyl specific binding in most of the human brain regions studied, suggesting that the major population of sites labeled by [3H]ohmefentanyl represented mu opioid receptors.

Seroepidemiology of HCV and HBV infection in northern China

The HCVAb positive rate in normal population in Beijing was 2.1% and HBsAg positive rate was 2.5%. There is an increasing tendency in the aged group. Plasmapheresis might have been the major cause of HCV transmission in blood donors in the Hebei area. There was a high prevalence of HCVAb and HBsAg in chronic liver diseases in the Beijing area and the HCVAb-positive rate significantly increased corresponding to disease progression.

The Neurospora mitochondrial tyrosyl-tRNA synthetase is sufficient for group I intron splicing in vitro and uses the carboxy-terminal tRNA-binding domain along with other regions

Neurospora mitochondrial tyrosyl-tRNA synthetase (mt tyrRS), which is encoded by nuclear gene cyt-18, functions in splicing of group I introns in mitochondria. Here, we overproduced functional cyt-18 protein in Escherichia coli and purified it to near homogeneity. The purified protein has splicing and tyrRS activities similar to those of cyt-18 protein isolated from mitochondria and is by itself sufficient to splice the mitochondrial large rRNA intron in vitro. Structure-function relationships in the cyt-18 protein were analyzed by in vitro mutagenesis. We confirmed that a small amino-terminal domain not found in bacterial tyrRSs is required for splicing activity, but not tyrRS activity. Two linker insertion mutations, which disrupt the predicted ATP-binding site, completely inhibit tyrRS activity but leave substantial splicing activity. Finally, deletions or linker insertion mutations in the putative carboxy-terminal tRNA-binding domain inhibit both tyrRS and splicing activities, although some have differential effects on the two activities. Our results show that the normal catalytic activity of the cyt-18 protein is not required for splicing and are consistent with the hypothesis that the protein functions by binding to the precursor RNA and facilitating formation of the correct RNA structure. Regions required for splicing are distributed throughout the cyt-18 protein and overlap, but are not identical to, regions required for tyrRS activity. The finding that the putative carboxy-terminal tRNA-binding domain is required for both tyrRS and splicing activities suggests that the mechanism for binding the intron has similarities to the mechanism for binding tRNA(Tyr).

Detection of human papilloma virus (HPV) in laryngeal carcinoma tissue

Using alpha-32P-dCTP labelled human papillomavirus type 16 DNA genome probe (cHPV 16 DNA, cloned and identified from a Chinese cervical invasive carcinoma), 3 HPV 16 genomic relative sequences were detected in 6 biopsies of laryngeal carcinoma. The results showed serious HPV infection in laryngeal carcinoma. This indicates that HPV infection may play an important pathogenetic role in cancer development.

[Analysis and comparison of acidic constituents in petroleum ether-soluble fraction of radix Rehmanniae and its processed products]

The acidic constituents in petroleum ether extract of the roots Rehmannia glutinosa f. hueichingensis were fractionated and analyzed by GC-MS. 19 Kinds of acidic constituents were identified and 11 of them (the main components) were compared between Rehmanniae Radix and its processed products.

[A distinct centro-peripheral gradient of development in dopaminergic amacrine cells of cat retina]

The centro-peripheral gradient of development in dopaminergic (DA) amacrine cells of cat retina has been studied by TH immunocytochemical method. Type I of TH immunoreactive neurons is typical DA cell. They reveal a clear centro-peripheral gradient of differentiation and maturation in space and time course during postnatal development. (1) At P1 stage, the TH I cells vary in TH immunoreactivity, soma sizes and dendritic maturation. Responding to degree of development, they can be divided into I1, I2 and I3. The more differentiated I1 cells, larger and darkly immuno-stained stellate cells mostly concentrates at central retina, while the less differentiated I3 cells, smaller and lightly immunostained irregular cells concentrate at peripheral retina. I2 cells of moderate differentiation distribute over all the retina. (2) During the postnatal development, from P1 to P13, the dense area of the TH I1 cells spreads peripherally in company with the increase of the total number of TH I1 cells, comprising the central 30% of the retina at P1, 65% at P6 and almost the whole of the retina by P13. After eye opening, as the TH I cells have spread at far peripheral region, the differences in soma diameters and dendritic maturation of TH I cells between central and peripheral retina decrease gradually and the centro-peripheral gradient of maturity of TH I cells becomes less distinct. At P23, no significant difference is visible in either soma diameter or dendritic maturation in these two areas: thus, the centro-peripheral gradient is no longer apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor and phorbol esters reduce the levels of the cognate mRNA for the LH/CG receptor

The LH/CG receptor of MA-10 Leydig tumor cells can be down-regulated by LH/CG, mouse epidermal growth factor (mEGF), cAMP analogues and phorbol esters. In a recent publication we showed that the LH/CG-induced down regulation of the LH/CG receptor is primarily due to an increase in the rate of degradation of the receptor, and occurs with little or no change in the levels of LH/CG receptor mRNA. Although relatively unimportant for the LH/CG-induced down-regulation of the LH/CG receptor, we also found that LH/CG can in fact elicit a reduction in LH/CG receptor mRNA and that this reduction is mediated by cAMP. These findings raised the possibility that the ability of other compounds to down-regulate the LH/CG receptor may be accompanied by decreases in LH/CG receptor mRNA. In an attempt to answer this question, we examined the possibility that the mEGF- or phorbol ester-induced down regulation of the LH/CG receptor is due to changes in LH/CG receptor mRNA. The experiments presented herein show that this is indeed the case.