Discovery of a brain promoter from the human transferrin gene and its utilization for development of transgenic mice that express human apolipoprotein E alleles

Transgenic mice carrying heterologous genes directed by a 670-bp segment of the regulatory sequence from the human transferrin (TF) gene demonstrated high expression in brain. Mice carrying the chimeric 0.67kbTF-CAT gene expressed TF-CAT in neurons and glial cells of the nucleus basalis, the cerebrum, corpus callosum, cerebellum, and hippocampus. In brains from two independent TF-CAT transgenic founder lines, copy number of TF-CAT mRNA exceeded the number of mRNA transcripts encoding either mouse endogenous transferrin or mouse endogenous amyloid precursor protein. In two transgenic founder lines, the chloramphenicol acetyltransferase (CAT) protein synthesized from the TF-CAT mRNA was estimated to be 0.10-0.15% of the total soluble proteins of the brain. High expression observed in brain indicates that the 0.67kbTF promoter is a promising director of brain expression of heterologous genes. Therefore, the promoter has been used to express the three common human apolipoprotein E (apoE) alleles in transgenic mouse brains. The apoE alleles have been implicated in the expression of Alzheimer disease, and the human apoE isoforms are reported to interact with different affinities to the brain beta-amyloid and tau protein in vitro. Results of this study demonstrate high expression and production of human apoE proteins in transgenic mouse brains. The model may be used to characterize the interaction of human apoE isoforms with other brain proteins and provide information helpful in designing therapeutic strategies for Alzheimer disease.

[nm23 gene product/NDPK expression and its clinical significance in human colorectal carcinoma]

The expression of nm23 gene product/NDPK was examined immunohistochemically in resected human colorectal carcinomas using anti-NDPK polyclonal antibody. Of the 103 carcinomas tested, 76.7% (79 cases) showed positive staining of nm23/NDPK in the primary lesions. In patients without regional lymph node metastasis, the positive staining rate (90.5%, 38/42) was significantly higher than that in those with nodal involvement (67.2%, 41/61). Inverse relationships were found between nm23/NDPK expression and tumor invasion or the progression of Dukes' staging. Expression of NDPK was positively associated with longer post-operative survival and the relationship was significant. Therefore, our data indicated that nm23 gene plays an important role in lymph node metastasis and invasion in colorectal carcinomas. The expression of nm23 gene product/NDPK may be a useful tool for prognosis of human colorectal carcinomas.

[Sequencing of polyhedrin gene of Leucania separata multiple capsid nuclear polyhedrosis virus by silver sequencing system]

The genome of LsNPV was digested with EcoRV and cloned into pBluescript. With the partial polyhedrin gene of Autographa californica as a probe, positive recombinants were screened by colony in situ hybridization, further characterized by sequencing, and designated as pLsEV and pLsPH5. The intact 741 bp polyhedrin gene of LsNPV is located on the two recombinants revealed by Silver Sequencing System, and shares 80.0% and 97.0% nucleotide identity of the coding sequence, 87.8% and 97.5% amino acid identity with AcMNPV and MbMNPV respectively. Glu is the richest amino acid, and Gln and Trp the poorest amino acid in the polyhedrin of LsNPV. The codons ended with pyrimidine were higher in the codon usage. There was a signal-peptide-like hydrophobic region of 26 amino acids in the N end of polyhedrin.

Ultraviolet B light induces G1 arrest in human melanocytes by prolonged inhibition of retinoblastoma protein phosphorylation associated with long-term expression of the p21Waf-1/SDI-1/Cip-1 protein

UVB irradiation inhibits melanocyte proliferation by causing arrest in G1 (D. Barker, K. Dixon, E. E. Medrano, D. Smalara, S. Im, D. Mitchell, G. Babcock, and Z. A. Abdel-Malek. Cancer Res., 55: 4041-4046, 1995). To determine how, after UVB irradiation, signal transduction pathways, DNA damage, and cell cycle arrest interact in the human melanocyte, we analyzed here the possible activation of tyrosine kinases, the serine-threonine kinases Baf-1 and ERK2, the status of the transcription factor c-fos, and the activation of cell cycle checkpoints induced by expression of p53 protein. We found that in contrast to the UVC response, exposure to UVB irradiation did not stimulate the above kinases. UVB light induced a prolonged c-fos expression, suggesting a mechanism of induction different from the transient expression elicited by growth factors. The tumor suppressor p53 and the p53-inducible cyclin-dependent kinase inhibitor protein p21Waf-1/SDI-1/Cip-1 were expressed at high levels for at least 2 days after UV-irradiation. In parallel, phosphorylation of Rb, the retinoblastoma tumor suppressor gene product, was halted in UVB-irradiated cells and correlated with the expression of the protein p21Waf-1/SDI-1/Cip-1. Our data define for the first time how UVB irradiation affects the expression of crucial regulatory events needed for cell cycle progression in the human melanocyte.

Cell type-specific and inflammatory-induced expression of haptoglobin gene in lung

BACKGROUND

Haptoglobin (HP) is a hemoglobin-binding protein and a major acute phase reactant. Recently, HP has been shown to possess antioxidant and angiogenic properties. HP is known to be produced mainly in the liver. Expression of HP in specific cells of nonhepatic origin including lung cells has not been studied before. The presence of extracellular plasma proteins in lung epithelial fluid has been assumed to be of blood serum origin.

EXPERIMENTAL DESIGN

To investigate the expression of the HP gene in lung, the presence of HP mRNA and the production of HP protein in the lung were examined by Northern blot analysis and immunoprecipitation, respectively. Cellular expression of HP during development and inflammation were studied by in situ hybridization with lung tissues derived from different gestational stages from baboons and mice and from mice treated with lipopolysaccharide.

RESULTS

Northern blot and in situ hybridization analyses established a high level of expression of HP in fetal and adult lung tissues, which were confined to the epithelial lining of the airways in mouse and baboon. After inflammation had been induced in vivo, expression of the HP gene rose fourfold in lung, an increase compatible with that observed in normal mouse liver. However, HP mRNA level was not significantly altered in airway epithelium. Instead, HP expression in alveolar epithelial cells, most likely type 2 cells, was strongly increased.

CONCLUSIONS

Our data suggest that locally synthesized HP provides a major source of antioxidant and/or antimicrobial activity in the mucus blanket as well as in the alveolar fluid in the lung. The regulation and cell type-specific expression of HP during development and inflammation indicate a protective role for HP in lung and confirm recent reports that HP plays important roles in protecting against infection and in repairing injured tissues.

Membrane formation on the surface of implanted posterior chamber intraocular lenses

PURPOSE

To study the prevention and treatment of the membrane formation on the lens surface after extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (PCIOL) implantation.

METHODS

We reviewed the records of 312 cataractous patients that had undergone ECCE with PCIOL implantation between 1989 and 1993. Postoperatively all patients were examined under slit-lamp microscopy. The membrane formation on the surface of PCIOL in pupilar area was divided into four grades. Two membranes of surgical removal were observed under a transmission electron microscopy. One PCIOL of surgical removal was observed under a scanning electron microscopy.

RESULTS

Of 312 patients, 21 had the membrane formation on the surface of the PCIOL postoperatively. The incidence of the membrane formation was 6.7%. Comparisons with cases of senile cataract showed the incidence to be significantly the highest among: 1. patients who had traumatic cataract (P < 0.05); 2. patients with complicated cataract (P < 0.05). Intraoperatively residual lens cortex and rupture of posterior capsule, interval time between the first and second eye operations less than 1 month are the main factors of membrane formation. The ultrastructure in membrane and cytology on the lens surface showed that the membrane on the surface of PCIOLs is usually composed of a cellular protein film and cellular elements, including macrophages, fibroblast-like cells, epithelioid cells, giant cells, fibroblasts and collagen fibrils, etc.

CONCLUSIONS

The cellular response on the surface of an implanted PCIOL is a chronic foreign-body inflammatory reaction and the membrane of the surface of implanted PCIOL is a reactive membrane of the foreign-body.

Dynamic extraction of visual evoked potentials through spatial analysis and dipole localization

The dynamic extraction of evoked potential is a problem of great interest in EEG signal processing. In this paper, a comprehensive method is presented which integrates spatial analysis and dipole localization to make full use of the spatial-temporal information contained in the multichannel stimulation records. A realistic double boundary head model is constructed through CT scans and a two-step method devised to overcome the ill-posed nature of the forward problem of EEG caused by the low conductivity of the skull. As a result, visual evoked potentials can be effectively extracted from only two consecutive records and the dynamic information of visual evoked potential thus procured. The efficiency of the presented method has been verified by means of computer simulation and a clinical experiment.

Nonaqueous biocatalytic degradation of a nerve gas mimic

Organophosphorus hydrolase has been shown to be an effective catalyst for the continuous decontamination of a nerve agent in a continuous gas phase reactor. Very small quantities of the enzyme are sufficient to enable detoxification of low concentrations of the nerve agent for extended periods of time. In the case where the nerve agent is at high concentrations (a liquid), the enzyme has also been shown to be active in biphasic mixtures of a solvent with water. The activity and specificity of the enzyme in both environments (continuous gas phase and biphasic mixture) obey classical models of enzyme kinetics. The activity of the enzyme in such extreme environments enables optimization of systems capable of continuous gas or liquid phase biocatalytic degradation of highly toxic chemicals.

Transmembrane Ca2+ gradient-mediated phosphatidylcholine modulating sarcoplasmic reticulum C(a2+)-ATPase

The sarcoplasmic reticulum (SR) C(a2+)-ATPase was purified and reconstituted into the sealed phospholipids vesicles with or without transmembrane Ca2+ gradient. The role of phospholipids, especially phosphatidylcholine (PC), in the modulation of C(a2+)-ATPase by transmembrane Ca2+ gradient was investigated. The results are as follows. (i) Incubated with phospholipids, the enzyme activity of the delipidated C(a2+)-ATPase is inhibited by Ca2+ and the highest inhibition is observed in the presence of PC. (ii) When there exists a transmembrane Ca2+ gradient (higher Ca2+ concentration inside vesicles, 1,000 mumol/L:50 mumol/L, similar to the physiological condition), the inhibition of C(a2+)-ATPase by transmembrane Ca2+ gradient can be only observed in the vesicles containing PC:PE, but not in those containing PS:PE or PG:PE. The highest inhibition is obtained at a 50:50 molar ratio of PC:PE (iii) By comparing the effects of PC differing in acyl chains, higher inhibition of C(a2+)-ATPase is observed in vesicles containing DPPC:PE and DOPC:PE, while no inhibition in DMPC:PE vesicles (iv) If the transmembrane Ca2+ gradient is in the inverse direction, the enzyme activity of C(a2+)-ATPase is inhibited whenever reconstituted with acidic or neutral phospholipids.

A comparative study of karyotypes of muntjacs by chromosome painting

We have used a combination of chromosome sorting, degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR), chromosome painting and digital image capturing and processing techniques for comparative chromosome analysis of members of the genus Muntiacus. Chromosome-specific "paints" from a female Indian muntjac were hybridised to the metaphase chromosomes of the Gongshan, Black, and Chinese muntjac by both single and three colour chromosome painting. Karyotypes and idiograms for the Indian, Gongshan, Black and Chinese muntjac were constructed, based on enhanced 4', 6-diamidino-2-phenylindole (DAPI) banding patterns. The hybridisation signal for each paint was assigned to specific bands or chromosomes for all of the above muntjac species. The interspecific chromosomal homology was demonstrated by the use of both enhanced DAPI banding and comparative chromosome painting. These results provide direct molecular cytogenetic evidence for the tandem fusion theory of the chromosome evolution of muntjac species.

Expression and inflammatory regulation of haptoglobin gene in adipocytes

Haptoglobin (HP) is the major hemoglobin binding protein which is synthesized mainly in the liver. It functions to prevent iron loss and kidney damage in human and other mammals. Recently, HP has been shown to possess antioxidant and angiogenic properties. As one of the major acute phase reactants, HP's levels in plasma increase significantly during inflammation, infection and malignancy. In this study, high levels of HP mRNA were found to be transcribed by adipocytes in addition to liver cells in mice. After inflammation had been induced in vivo, expression of the haptoglobin gene rose six-fold in adipose tissue, an increase compatible with that observed in the normal mouse liver. The expression of HP by adipocytes presents new directions in which HP's role as an antioxidant or as an angiogenic factor can be investigated.

A human (3.3 kb) haptoglobin-CAT transgene is modulated in lungs of transgenic mice by inflammation

Four independent lines of transgenic mice were produced carrying integrated copies of a chimeric gene composed of 3.3 kb of the human haptoglobin 5' regulatory region fused to the CAT (chloramphenicol acetyl transferase) reporter gene. Although the endogenous mouse haptoglobin (Hp) and human haptoglobin (HP) genes express mainly in liver and lung, expression of the human 3.3-kb HP-CAT transgene was not detected until after induction of inflammation and then only in lungs. The results indicated that the transgene maintained the regulatory DNA elements required for lung specific responsiveness to inflammation in vivo but lacked the DNA sequence required for robust expression in liver. The DNA sequence(s) responsible for the normally high level of HP expression in liver either reside outside the 3.3-kb regulatory region of the HP chimeric gene or this region contains a suppressor sequence affecting tissue specific expression in the liver.

Estimation of dynamic chemoresponsiveness in wakefulness and non-rapid-eye-movement sleep

We developed a method for quantifying dynamic chemoresponsiveness on the basis of the ventilatory response to pseudorandom binary CO2 stimulation. The dynamic chemoreflex gain (GD) and effective time delay (TDeff) relating breath-to-breath fluctuations in alveolar PCO2 to ventilation were evaluated at frequencies between 0 and 0.05 Hz. Application of the method to simulated "data" showed that estimation errors in GD and TDeff were most likely to be minimized in the range of 0.01-0.03 Hz, corresponding to periodicities of 30-100 s. Estimation of TDeff was generally more susceptible to error than that of GD because of the limited time resolution of the breath-by-breath measurements. In eight awake normal adults, we compared estimates of GD derived from the pseudorandom binary CO2 stimulation test with peripheral and central hypercapnic sensitivities deduced from single-breath and Read rebreathing measurements in the same subject. GD at 0.02 Hz was highly correlated with peripheral hypercapnic sensitivity but poorly correlated with central hypercapnic sensitivity, underscoring the importance of the peripheral chemoreflexes in mediating ventilatory responses to phasic stimuli. Application of the procedure to a different group of 10 healthy volunteers during wakefulness and stage 2 sleep showed decreases in GD in 8 subjects but increases in 2 subjects. However, for the group as a whole, GD and TDeff did not change significantly between wakefulness and sleep. The proposed method may provide information more pertinent to periodic breathing than traditional CO2 response tests do, since the chemoreflex responses to phasic variations in blood gases are likely to be important in determining ventilatory control during sleep.

SP-A deficiency in primate model of bronchopulmonary dysplasia with infection. In situ mRNA and immunostains

The surfactant protein secretory cells in airway and alveolar epithelium were studied in premature baboons with bronchopulmonary dysplasia and superimposed infection. PRN animals were delivered by hysterotomy at 140 d gestational age and ventilated on clinically appropriate oxygen for a 16-d experimental period. To assess 0 time and sacrifice time gestational parameters, 140 and 156 d were studied. BPD animals were delivered at 140 d and ventilated with positive-pressure ventilation and an FIO2 of 1.0 for 11 d followed by 5 d of oxygen sufficient to maintain PAO2 at 40 to 50 mm Hg. BPD-infected animals were comparably ventilated and treated like the BPD group except that 10(8) E. coli organisms were endotracheally instilled on Day 11. In situ hybridization studies for mRNA expression of SP-A, SP-B, and SP-C revealed that an SP-A mRNA deficiency, present at 140 d, persisted in the BPD and BPD-infected groups, whereas SP-A mRNA was abundant in PRN and 156 d gestation control groups. SP-B and SP-C mRNA expression in the two hyperoxically injured groups was particularly extensive in cells around peribronchiolar and perivasicular sites. Immunostaining with SP-A, SP-B, and SP-C antibodies showed variable staining patterns. The study clearly demonstrates that a deficiency of SP-A mRNA expression persists in chronic lung injury and that variable protein staining patterns are manifested depending upon the underlying pathology.

Nitrogen regulation of nasA and the nasB operon, which encode genes required for nitrate assimilation in Bacillus subtilis

The divergently transcribed nasA gene and nasB operon are required for nitrate and nitrite assimilation in Bacillus subtilis. The beta-galactosidase activity of transcriptional lacZ fusions from the nasA and nasB promoters was high when cells were grown in minimal glucose medium containing poor nitrogen sources such as nitrate, proline, or glutamate. The expression was very low when ammonium or glutamine was used as the sole nitrogen source. The repression of the genes during growth on good sources of nitrogen required wild-type glutamine synthetase (GlnA), but not GlnR, the repressor of the glnRA operon. Primer extension analysis showed that the -10 region of each promoter resembles those of sigma A-recognized promoters. Between the divergently oriented nasA and nasB promoters is a region of dyad symmetry. Mutational analysis led to the conclusion that this sequence is required in cis for the activation of both nasA and nasB. The derepression of these genes in a glnA mutant also required this sequence. These results suggest that an unidentified transcriptional activator and glutamine synthetase function in the regulation of nasA and the nasB operon.

Polyclonals to beta-amyloid(1-42) identify most plaque and vascular deposits in Alzheimer cortex, but not striatum

Alzheimer's beta-peptides (A beta) aggregation rates depend on A beta length. We made synthetic peptide antisera to A beta 34-40 and 37-42. Purified anti-34-40 preferentially recognizes beta 1-40, vascular amyloid and a subset of plaques while purified anti-37-42 recognizes A beta 1-42 and not A beta 1-40 in dot and Western blots and immunoprecipitates; 37-42 precipitates a small percentage of fibroblast secreted A beta and strongly stains all deposits identified by monoclonals to A beta on adjacent sections from frontal cortex, but not in dorsal striatum.

[Effects of fibronectin on cytodifferentiation (T56) of human squamous cell carcinoma of tongue]

Fibronectin (FN) are large glycoproteins that have been implicated in a wide variety of cellular properties, including cell adhesion, morphology, cytoskeletal organization, migration, differentiation, and oncogenic transformation. T56 cells were treated with 20, 50, and 100 micrograms/ml of FN for 48 h, and the changes in cells were analysed qualitatively and quantitatively with the methods of transmission electron microscopy, enzyme cytochemistry, and cell electrophoresis, etc. The studies were made to test the effects of FN on T56 cells in biological behaviour in terms of cell growth, multiplication, cell metabolism, cell electrophoresis and surface morphology. The results indicated that FN could partially restore T56 cell normal epidermic cell's phenotype, inhibit cell mitosis, increase contact of cells, decrease the number of microvilli and ruffles, and promote cell oxybiotic metabolism. These results suggest that FN might relate in many aspects to the biological behaviour of T56 cell and could affect changes in the behaviour.

Further study on the spontaneous partial folding of chicken heart apocytochrome c

It has been previously reported (Biochem. Mol. Biol. Int., 30(5), 867-876, 1993) that chicken heart apocytochrome c has stronger tendency to fold spontaneously in aqueous solution than those from other species, and the relevance of its folding state with its ability to penetrate across the lipid bilayers has also been studied. In the present paper, the spontaneous folding characteristics of chicken heart apocytochrome c was further examined by the studies of Fourier-transform infrared spectra, the properties of intrinsic tryptophan fluorescence, and the measurements of hydrophobicity. In addition, it was also demonstrated that the partially-folded apocytochrome c is easily to be aggregated and hence relatively incompetent for translocation across the phospholipid bilayers.

[Infantile indirect inguinal hernia treated with laparoscopy high ligation of hernial sac]

22 cases of infantile indirect inguinal hernia were treated with laparoscopy high ligation of hernial sac. They were followed up for 9-18 months, the primary results were satisfactory and quite encouraging. The merits of this newly developed method are: The technique is relatively simple and less of postoperative complications. The technique and key point of the method were described in detail.