[The damaging effect of activated human neutrophils on isolated perfused rat lungs--the role of elastase]

Human neutrophil and its elastase play an important role in the pathogenesis of various lung diseases. We investigated the damaging effect of human neutrophils stimulated with PMA (phorbol myristate acetate 10ng/ml) or calcium ionophase A23187 (2ng/ml) on isolated perfused rat lungs. The study specimens consisted of 4 groups of animals. A control, B perfused with human neutrophils, C perfused with human neutrophils stimulated with PMA, and D perfused with human neutrophils stimulated with A23187. By using the ELISA method, we found that the level of human neutrophil elastase (HNE) in perfusate increased significantly at 30min (1.68 +/- 0.79ng/ml P < 0.05) and 60min (2.35 +/- 0.87 ng/ml P < 0.01) after PMA stimulating, but the HNE in the lung lavage fluid of the same group only slightly increased and the concentration of protein in lavage fluid did not change. After stimulating with A23187, the concentration of HNE in perfusate increased markedly at 30min (4.03 +/- 1.96ng/ml P < 0.01) and maintained at high level (P < 0.01). There was a significant increase of HNE level in lung lavage fluid (2.49 +/- 0.61ng/ml) from group D rat lungs, compared with group A, B or C, and the protein as well (1.61 +/- 0.58mg/ml P < 0.05). All the results indicate that the stimulated human neutrophils can release elastase in perfused rat lung. Neutrophil stimulated with A23187 can increase pulmonary permeability and injure the lung. We suggest that the lung damage, caused by human neutrophils, may be the effect of neutrophil elastase or the synergistic effect with some other substances derived from neutrophil.

Nucleotide sequence and expression of the genes for the alpha and beta subunits of phycocyanin in Cyanidium caldarium

The nucleotide sequence of the plastid-encoded operon containing genes for the alpha (cpcA) and beta (cpcB) subunits of phycocyanin in the unicellular red alga Cyanidium caldarium is described. cpcB is located 5' to cpcA and the two genes are separated by a 102-bp spacer region. The transcription start site of cpcBA was mapped to 80 bp upstream of the ATG initiation codon of cpcB. Promoter-like elements similar to the -10 (TATAAT) and -35 (TTGACA) consensus promoters in bacteria were found 6 and 31 bp upstream of the transcription initiation site. Northern blotting revealed an abundant 1.3-kb cpcBA transcript in illuminated cells, but this transcript was undetectable in dark-grown cells. Expression levels of cpcBA in cells incubated with 10(-6) M heme in the dark were similar to those in cells illuminated for 24 h. Cells illuminated with 150 microM gabaculine (an inhibitor of delta-aminolevulinate synthesis) or 10 mM levulinic acid (an inhibitor of delta-aminolevulinate dehydrase) lacked detectable cpcBA transcripts. In cells illuminated with 200 microM N-methyl-mesoporphyrin IX (an inhibitor of ferrocheletase), inhibition of cpcBA expression and phycocyanin synthesis was similar. These results provide strong evidence that light induction of the cpcBA operon is dependent on synthesis of heme.

Joint wavelet-transform correlator for image feature extraction

We describe a joint wavelet-transform correlator in which the wavelet function is combined with the input image as the input joint image to realize the wavelet transform of the objective image. The Haar wavelet and the Roberts filter are chosen as the wavelet functions to extract the features of the objective image. The relationship of the Haar wavelet and the Roberts filter is analyzed mathematically based on admissible condition of the wavelet. Computer simulations are provided to verify the theory and to illustrate the performance of this correlator.

[TLC scanning determination of baicalin content in niuhuang qingxin pills]

Baicalin in the samples was extracted with ultrasonic wave, the extract was spotted on thin-layer plates of gel GF254 and developed with the mobile phase consisting of toluene-ethylacetate-formic acid (2:3:2.2). Determinations were carried out with Shimadzu CS-930 TLC scanner with lambda s = 280 nm and lambda R = 207 nm. The linear range was 0.46-4.6 micrograms/ml. The average recovery of baicalin from the samples was 98.35%, RSD = 2.82%.

[Cloning, sequencing and characterizing repetitive DNA of Glycine max]

One satellite DNA family, cloned from Glycine max, was sequenced and chracterized. The unit of the repetitive sequences was 91bp. They concentrated on the arms of chromosomes M2 and M11, and spreaded on whole chromosomes Sm7 and M12. Southern blot analysis with 18 acessions, belonged to subgenus Glycine and subgenus Soj a of genus Glycine, showed that the repetitive sequences were specific to subgenus Soj a. It was subgenus specific repetitive sequence. This result, from another aspact, supported the idea that the three species in subgenus Soj a should be considered as one species.

[Effect of GG on the occurrence of tongue retropulsion--an experimental observation of electromyography]

To evaluate the effect of GG activity on tongue backwardness during sleep, we conducted experiments on 16 rabbits. The electric activities of the muscles involved in tongue motion were recorded in different phases (wakefulness, presnoring and snoring) with unipolar electrodes inserted into the muscles under direct vision. The observations demonstrated that GG played a more active role in the occurrence of tongue backwardness during sleep.

A Pit-1 binding site in the human renin gene promoter stimulates activity in pituitary, placental and juxtaglomerular cells

One of the principal aims of our research is to determine the mechanisms which direct renin gene expression to different sites. We recently demonstrated that human renin (hRen) 5'-flanking DNA sequences -148 +/- 11 can drive the transient expression of a linked luciferase reporter gene transfected into pituitary GC cells. This activity was found to be dependent on the binding of Pit-1 to a site approximately 70 bp upstream from the transcription start site. Pit-1 is a pituitary-specific transcription factor which is involved in directing the cell-specific expression of growth hormone (GH) and prolactin (PRL) gene expression to somatotrope and lactotrope cells of the anterior pituitary. Thus, Pit-1 may be play a role in directing the expression of renin to primate lactotrope cells. Renin promoter-driven luciferase or CAT hybrid genes were found to be expressed following transfection into primary, or early passage cell cultures of placental chorionic membranes, and the renin-secreting renal tumor cell line As4.1. As with GC cells, deletion or mutagenesis of the Pit-1 site reduced activity several-fold in both placental and renal cells. These results suggest that members of the POU family of transcription factors, or some other closely related group such as the Hox proteins, participate in directing renin gene expression to placental and juxtaglomerular cells.

Dietary calcium reduces blood pressure, parathyroid hormone, and platelet cytosolic calcium responses in spontaneously hypertensive rats

Dietary calcium effects on blood pressure, parathyroid hormone (PTH), and platelet cytosolic calcium concentrations were investigated. The dietary calcium (low, 0.2%; medium, 0.5%; and high, 2.0% wt/wt) was supplemented in spontaneously hypertensive rats from 6 through 22 weeks of age. Mean systolic blood pressure was decreased by age 12 weeks with calcium supplementation (low, 227 +/- 6 mm Hg; medium, 211 +/- 6 mm Hg; and high, 182 +/- 7 mm Hg; P < .001). By the 10th week of age, the low calcium group had significantly (P < .05) more elevated (44 +/- 2.3 pg/ml) plasma PTH compared with the high calcium-supplemented group (15 +/- 4.5 pg/mL). Regression analysis showed a significant (P < .001) positive correlation (r = 0.3) between systolic blood pressure and PTH. The platelet cytosolic calcium concentration was determined using the fura-2 method. The basal calcium was 134 +/- 5.5 nmol/L for the low calcium group and thrombin increased to 228 +/- 8 nmol/L (P < .0001; +70% change). The normal calcium group had 202 +/- 8 nmol/L; thrombin increased to 239 +/- 10 nmol/L (P < .0026; +19% change). The high calcium group had basal levels 145 +/- 7 nmol/L, with thrombin stimulating to 212 +/- 8 nmol/L (P < .0001; +46% change). Although thrombin increased platelet cytosolic calcium concentration in all groups, normal and high dietary calcium groups had smaller percentage increases (51% and 24% lesser, respectively) compared with the low dietary calcium group.(ABSTRACT TRUNCATED AT 250 WORDS)

Renin gene promoter activity in GC cells is regulated by cAMP and thyroid hormone through Pit-1-dependent mechanisms

Transcriptional activity of human renin gene (hREN) 5'-flanking DNA sequences in pituitary cells is highly dependent on binding of the pituitary-specific transcription factor Pit-1. Pit-1 has been implicated in cAMP regulation of a number of pituitary genes and has also been shown to interact with thyroid hormone (T3) receptors in mediating T3 responsiveness of the rat growth hormone gene. In the present study we examine the effects of forskolin and T3 on the expression of luciferase hybrid genes containing hREN 5'-flanking DNAs (hREN.luc) transiently transfected into the pituitary cell line GC. Basal activities of all hREN.luc constructs transfected into cells grown in media containing serum stripped of hormones were low. Addition of forskolin stimulated expression up to 48-fold, depending on the hREN sequences present. The hREN sequence -148 to +18 was sufficient for both maximal expression and maximal stimulation by forskolin. Mutagenesis of the Pit-1 site between -82 and -58 reduced forskolin induction 4-5-fold. In addition to the Pit-1 site, the sequence between -148 and -98 was also required for maximal activity and forskolin induction. T3 on its own had no effect on hREN promoter activity in GC cells, but suppressed the effects of forskolin. Gel mobility shift and Western blot analyses indicated that forskolin treatment had no effect on Pit-1 DNA binding or Pit-1 levels. However, T3 reduced Pit-1 levels which was reflected in lower DNA binding under the conditions employed. Taken together, these findings emphasize the importance of cAMP-dependent mechanisms in directing renin gene expression.

Nucleotide sequence of polymerase chain reaction product amplified from Rickettsia japonica DNA using Rickettsia rickettsii 190-kilodalton surface antigen gene primers

The PCR product amplified from Rickettsia japonica with the primer pair Rr 190.70p and Rr 190.602n of R. rickettsii 190-kDa antigen gene was cloned into M13mp19 RF DNA at the Eco RI site and sequenced by chemiluminescent DNA sequencing. The sequence revealed a molecular size of 533 base pairs (bp). The primer-flanking region of 491 bp, an open reading frame, was compared with the corresponding region of R. rickettsii, demonstrating 35 nucleotide substitutions in R. japonica. The sequence of primer portions in R. japonica DNA was also analyzed, revealing one nucleotide substitution in the Rr 190.70p and two in the Rr 190.602n portion. The homology in the overall sequence of PCR-amplified regions between R. japonica and R. rickettsii was 93% in nucleotide and 85% in putative amino acid structure. The sequence contains no cleavage site for the restriction endonuclease AfaI but two PstI sites giving three fragments of 121, 159, and 253 bp, which differentiated R. japonica from other spotted fever group rickettsiae in addition to R. rickettsii. The cleavage sites for endonucleases AluI, HinfI, and MunI that disappeared or appeared in the sequence by nucleotide substitution differentiated R. japonica from others, as did PstI. The estimation of molecular size of DNA fragments on polyacrylamide gel electrophoresis is discussed.

Pituitary-specific transcription factor (Pit-1) binding site in the human renin gene 5'-flanking DNA stimulates promoter activity in placental cell primary cultures and pituitary lactosomatotropic cell lines

Renin gene expression is limited to a number of specific tissues, including the kidney, adrenal glands, reproductive organs (of particular relevance to this study, the placenta), and the pituitary gland. In the present study, we investigated the human renin (hRen) 5'-flanking DNA sequences required to drive the expression of a luciferase reporter gene in placental and pituitary cells and in two cell lines, 293 and JEG-3, which have been proposed as model systems with which to study transcriptional regulation of renin genes. The activities of specific sequences in the hRen 5'-flanking DNA sequences in human placental cell primary cultures were very similar to those that we previously reported in pituitary cells, suggesting the involvement of common promoter elements and related transcription factors. Accordingly, the binding site for the pituitary-specific transcription factor (Pit-1) was the major determinant of renin promoter activity in both pituitary and placental cells. Gel mobility shift analysis showed a placental nuclear factor with a gel mobility different from that of Pit-1. However, Northern blot analysis failed to demonstrate abundant Pit-1-related mRNAs in renin-expressing cultures of chorionic and decidual cells, suggesting that the placental factor is not closely related to Pit-1. Although a factor from 293 cells also bound to the Pit-1 site, it had gel mobility shift characteristics different from Pit-1 and the placental factor. Moreover, the low promoter activity in 293 cells was independent of this site or, indeed, of sequences upstream from the TATA box. In JEG-3 cells, renin 5'-flanking DNA sequences showed virtually no transcriptional activity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Detection of P-glycoprotein expression in patients with acute leukaemia and clinical significance]

Anti-P-glycoprotein monoclonal antibody JSB-1 and alkaline phosphatase-anti-alkaline phosphatase (APAAP) immunocytochemical staining technique were used to study the relation between P-glycoprotein expression and clinical multidrug resistance (MDR) in 42 patients with acute leukaemia (23 ALL and 19 ANLL). 10 of 17 patients who were diagnosed as refractory or relapsed acute leukaemia were positive with P-glycoprotein expression, while only 3 of 14 newly diagnosed and 1 of 11 who were in complete remission were positive. The preliminary results indicated that there was a close association between the P-glycoprotein expression and the clinical resistance to chemotherapy in some patients.

Role of collagen metabolism changes in the pathogenesis of pulmonary hypertension in rats and its reversibility

Pulmonary arterial pressure (PAP) was increased obviously in rats after 3 days of normobaric hypoxic exposure and reached a maximum at 14 days of hypoxia. It remained at the same level during prolonged hypoxic exposure of up to 21 days. Right ventricular weight (RV/LV+S) and hydroxyproline (HP) content in the pulmonary artery began to increase at day 7. HP content had increased much faster than the relative rate of increase of PAP after 14 days, but HP content in the thoracic aorta showed no change. The relative proportion of type I to III collagen increased significantly, and compliance of the pulmonary vessels obviously decreased. All parameters returned to the normal range within 14 days after recovery from hypoxia, except for HP content as expressed per vessel. 764-3 treatment obviously attenuated most of the changes caused by hypoxia, though it had no effect on compliance of the pulmonary vessels. It is suggested that collagen, especially type I collagen, accumulation may play an important role in maintaining pulmonary hypertension. 764-3 has certain protective effects and may be useful in the treatment of early chronic obstructive pulmonary disease.

Deuterium exchange of alpha-helices and beta-sheets as monitored by electrospray ionization mass spectrometry

Deuterium exchange was monitored by electrospray ionization mass spectrometry (ESI-MS) to study the slowly exchanging (hydrogen bonded) peptide hydrogens of several alpha-helical peptides and beta-sheet proteins. Polypeptides were synthetically engineered to have mainly disordered, alpha-helical, or beta-sheet structure. For 3 isomeric 31-residue alpha-helical peptides, the number of slowly exchanging hydrogens as measured by ESI-MS in 50% CF3CD2OD (pD 9.5) provided estimates of their alpha-helicities (26%, 40%, 94%) that agreed well with the values (17%, 34%, 98%) measured by circular dichroic spectroscopy in the same nondeuterated solvent. For 3 betabellins containing a pair of beta-sheets and a related disordered peptide, their order of structural stability (12D > 12S > 14D > 14S) shown by their deuterium exchange rates in 10% CD3OD/0.5% CD3CO2D (pD 3.8) as measured by ESI-MS was the same as their order of structural stability to unfolding with increasing temperature or guanidinium chloride concentration as measured by circular dichroic spectroscopy in water. Compared to monitoring deuterium exchange by proton NMR spectrometry, monitoring deuterium exchange by ESI-MS requires much less sample (1-50 micrograms), much shorter analysis time (10-90 min), and no chemical quenching of the exchange reaction.

Characterization of glycosylated and catalytically active recombinant human alpha-galactosidase A using a baculovirus vector

Fabry disease is an X-linked inborn error of glycolipid metabolism caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (GalA; EC 3.2.1.22). In order to obtain large quantities of this human enzyme for physical characterization and for the development of new approaches for enzyme therapy, we constructed derivatives of the Autographa californica nuclear polyhedrosis virus that produce the human enzyme. The recombinant GalA (re-GalA) is produced at high levels, and is active with both the artificial substrate, 4-methylumbelliferyl-alpha-D-galactopyranoside, and the natural in vivo substrate, trihexosylceramide. The purified re-GalA is glycosylated and is taken up by normal and Fabry fibroblasts in cell culture. Mass spectral analysis of total monosaccharides released by hydrazinolysis indicates that it contains fucose, galactose, mannose and N-acetylglucosamine. Amino-acid sequence analysis of six proteolytic peptides corresponded to sequences predicted by the cDNA. The molecular masses of the purified enzyme, estimated by electrospray mass spectroscopy and laser desorption time-of-flight analysis are 46.85 and 46.62 kDa, respectively, approx. 10% greater than the polypeptide portion predicted by the cDNA. The recombinant enzyme retains significant catalytic activity after modification with poly(ethylene glycol), a treatment which decreases the immunogenicity and increases the circulation life of many proteins used therapeutically.

ICAM-1 (CD54) expression on B lymphocytes is associated with their costimulatory function and can be increased by coactivation with IL-1 and IL-7

Recent studies have demonstrated that acute lymphoblastic leukemia-derived pre-B cell lines are deficient in their costimulatory function for T cell proliferation in response to the mitogen Con A and the superantigens TSST-1 and SEB. Stimulation of these pre-B cells with IL-7 increased their costimulatory function which involved the B7/CD28 pathway. In the present study, we stimulated T cells with Con A, TSST-1, and SEB in the presence of peripheral blood B lineage cells that do not constitutively express B7/BB1 on their surface and investigated whether their costimulatory function could also be enhanced by IL-7. We found that, in the presence of IL-1, stimulation with IL-7 increased the costimulatory function of B cells and their surface expression level of ICAM-1 (CD54). We then investigated whether costimulatory B cell function could be inhibited by blocking the ICAM-1/LFA-1 pathway. Addition of anti-ICAM-1 mAb to the coculture of T and B cells inhibited T cell proliferation by approximately 20%. In contrast, addition of anti-LFA-1 beta (CD18) mAb, directed against the T cell ligand of ICAM-1, inhibited T cell proliferation almost completely. To determine the role of ICAM-1 in costimulatory B cell function, we sorted B cells into ICAM-1low-and ICAM-1high-expressing populations. We found that B cells expressing high levels of surface ICAM-1 elicited significantly higher T cell responses than those with low levels, suggesting that the expression level of ICAM-1 on peripheral blood B cells correlates with their costimulatory function.

Engineering of betabellin 14D: disulfide-induced folding of a beta-sheet protein

The betabellin target structure consists of 2 32-residue beta sheets packed against each other by hydrophobic interactions. We have designed, chemically synthesized, and biophysically characterized betabellin 14S, a single chain, and betabellin 14D, the disulfide-bridged double chain. The 32-residue nongenetic betabellin-14 chain (HSLTASIkaLTIHVQakTATCQVkaYTVHISE, a = D-Ala, k = D-Lys) has a palindromic pattern of polar (p), nonpolar (n), end (e), and beta-turn (t,r) residues (epnpnpnttnpnpnprrpnpnpnttnpnpnpe). Each half contains the same 14-residue palindromic pattern (underlined). Pairs of D-amino acid residues are used to favor formation of inverse-common (type-I') beta turns. In water at pH 6.5, the single chain of betabellin 14S is not folded, but the disulfide-linked betabellin 14D is folded into a stable beta-sheet structure. Thus, folding of the covalent dimer beta-bellin 14D is induced by formation of the single interchain disulfide bond. The binary pattern of alternating polar and nonpolar residues of its beta-sheets is not sufficient to induce folding. Betabellin 14D is a very water-soluble (10 mg/mL), small (64 residues), nongenetic (12 D residues) beta-sheet protein with properties (well-dispersed proton NMR resonances; Tm = 58 degrees C and delta Hm = 106 kcal/mol at pH 5.5) like those of a native protein structure.

[Long-term culture of normal and leukemia bone marrow cells]

Using long-term bone marrow culture (LTBMC), we studied the in vitro growth status of bone marrow nucleated cells from 5 normal subjects and 14 patients with acute leukemia. The results showed that LTBMC could support normal hematopoiesis selectively, and in the meantime, inhibit the leukemic progenitor growth. Our preliminary clinical application indicated that this culture system could be used to purge the autologous bone marrow graft in vitro for allogeneic bone marrow transplantation.

Structure of murine polyomavirus complexed with an oligosaccharide receptor fragment

The polyomaviruses are non-enveloped, icosahedrally symmetrical particles with circular double-stranded DNA genomes. The outer shell of the virion contains 360 copies of viral protein VP1 (M(r) approximately 42K) arranged in pentamers. We report here the structure at 3.65 A resolution of murine polyomavirus ('polyoma') complexed with an oligosaccharide receptor fragment. This structure has been determined using the previously described model of simian virus 40 (SV40). Although very similar in structure to SV40, polyoma has interesting biological differences. Cell-surface N-acetyl neuraminic acid (sialic acid) is required for polyoma infectivity, but not for SV40. Polyoma attaches to the surface of susceptible cells by stereospecific recognition of oligosaccharides terminating in (alpha 2,3)-linked sialic acid. Studies of pathogenicity show that the specificity of viral binding to such oligosaccharides is an important determinant of the virus' ability to establish a disseminated infection and to induce tumours in the natural host. The complex described here show how polyoma recognizes the receptor fragment and how strains with different receptor specificities can distinguish between alternative ligands. The results also suggest an explanation for the large disparity in pathogenicity exhibited by strains differing in only one amino-acid residue of VP1.

Precision and accuracy of regional radioactivity quantitation using the maximum likelihood EM reconstruction algorithm

The imaging characteristics of maximum likelihood (ML) reconstruction using the EM algorithm for emission tomography have been extensively evaluated. There has been less study of the precision and accuracy of ML estimates of regional radioactivity concentration. The authors developed a realistic brain slice simulation by segmenting a normal subject's MRI scan into gray matter, white matter, and CSF and produced PET sinogram data with a model that included detector resolution and efficiencies, attenuation, scatter, and randoms. Noisy realizations at different count levels were created, and ML and filtered backprojection (FBP) reconstructions were performed. The bias and variability of ROI values were determined. In addition, the effects of ML pixel size, image smoothing and region size reduction were assessed. Hit estimates at 3,000 iterations (0.6 sec per iteration on a parallel computer) for 1-cm(2) gray matter ROIs showed negative biases of 6%+/-2% which can be reduced to 0%+/-3% by removing the outer 1-mm rim of each ROI. FBP applied to the full-size ROIs had 15%+/-4% negative bias with 50% less noise than hit. Shrinking the FBP regions provided partial bias compensation with noise increases to levels similar to ML. Smoothing of ML images produced biases comparable to FBP with slightly less noise. Because of its heavy computational requirements, the ML algorithm will be most useful for applications in which achieving minimum bias is important.

Prevention of postoperative gastroesophageal reflux by preservation of lower esophageal sphincter in partial esophagectomy

Postoperative reflux esophagitis is a common complication after partial removal of the esophagus and the whole gastric cardia for reconstruction through esophagogastrostomy. In 10 cases, the lower esophageal sphincter (LES) was preserved for a length of 2.05 +/- 0.33cm (mean +/- S) during partial esophagectomy for benign or malignant lesion at the middle and lower portion of the thoracic esophagus. The mean value of the LES pressures measured two weeks after operations was 2.40 +/- 0.64 kPa (18 +/- 4.8 mmHg) and the postoperative X-ray barium meal examination revealed no evidence of gastroesophageal reflux. Our study suggested that the preserved LES should effectively act as a functional barrier against the development of reflux esophagitis.

Crystal structure of the repetitive segments of spectrin

The elongated proteins of the spectrin family (dystrophin, alpha-actinin, and spectrin) contain tandemly repeated segments and form resilient cellular meshworks by cross-linking actin filaments. The structure of one of the repetitive segments of alpha-spectrin was determined at a 1.8 angstrom resolution. A segment consists of a three-helix bundle. A model of the interface between two tandem segments suggests that hydrophobic interactions between segments may constrain intersegment flexibility. The helix side chain interactions explain how mutations that are known to produce hemolytic anemias disrupt spectrin associations that sustain the integrity of the erythrocyte membrane.

Refinement and analysis of the structure of the first two domains of human CD4

The structure of a fragment of human CD4 containing two immunoglobulin (Ig)-like domains has been determined by X-ray crystallography and refined at 2.2 A resolution. The structure determination involved iterative building and simulated-annealing refinement, beginning with a partial model. Comparison of domain 1 with an Ig variable domain shows that CD4 has a long and prominent CDR2-like loop (the C"C" corner) and shortened CC' and FG loops (which mediate dimerization in IgV modules). Comparison of domain 2 with Ig modules and domain 1 shows that it can be described as a truncated Ig V domain, in which strands C" and D are deleted. The intersheet disulfide in domain 2 is absent, and there is an altered packing of the two beta-sheets together with a remodeling of the hydrophobic core. The interface between domains 1 and 2 is a lap joint with an extensive hydrophobic surface. The key features of domain 1 that contribute to the interface are found at corresponding positions in domain 2, leading us to propose that the contact between domains 2 and 3 will resemble the one between domains 1 and 2.

Hemodynamic and nonhemodynamic mechanisms of experimental pulmonary edema in rats and the effects of anisodamine and tetramethylpyrazine--estimation of blood gas analysis, RBC superoxide dismutase and prostaglandin E2 in plasma and bronchoalveolar lavage (Part 3)

Anisodamine (ADM, 654-2, 30 mg/kg) and tetramethylpyrazine (TMP, 120 mg/kg) have shown an apparent preventive effect on pulmonary edema (PE). In this study, the nonhemodynamic mechanism was studied: The dynamic changes of PaO2, O2Sat, PaCO2, and blood pH were measured, and RBC superoxide dismutase (SOD) and plasma and bronchoalveolar lavage (BAL) PGE2 levels were estimated. It was concluded that ADM and TMP exerted inhibitory effects on the hypoxic state. The ability of ADM and TMP to adjust RBC SOD and PGE2 levels may be one of the preventive mechanisms of the drugs.

Problems of controlling the optical thickness of infrared coatings during deposition

Special problems that influence the accuracy of controlling the optical thickness of infrared coatings during deposition are discussed.

Molecular cloning of M6: identification of a PLP/DM20 gene family

M6 is a membrane glycoprotein that is expressed on central neurons and certain polarized epithelia from early developmental stage. Antibodies against M6 interfere with cerebellar neurite outgrowth in vitro. Two closely related cDNAs were obtained by expression cloning, both of which showed high homology with the major CNS myelin protein PLP/DM20. Although M6 and PLP/DM20 share many molecular characteristics, in situ hybridization revealed nonoverlapping distributions of their mRNAs in mouse CNS. The identification of a gene family including neuron-specific M6 and glia-specific PLP/DM20 in CNS suggests a broader functional role for these molecules than myelination.

Free energies for refolding of the common beta turn into the inverse-common beta turn: simulation of the role of D/L chirality

Quantitative estimates of the Gibbs free-energy change (delta G) for refolding of one beta-turn conformation into another would assist rational protein design. For beta-turn models, we studied a chirally representative set of nine peptides of the form CH3CO-L1-L2-NHCH3, where loop residues L1 (i + 1) and L2 (i + 2) are achiral Gly (G), L-Ala (A), or D-Ala (a). The stabilities of their common (type I) and inverse-common (type I') beta-turn conformers (GGI is the type-I GG conformer, etc.) were estimated by free-energy simulations using explicit water molecules. An alpha-hydrogen atom of a Gly residue at L1 or L2 was replaced by a methyl group by slow growth. The resulting conformers were less stable than GGI and GGI' by about 1-3 kcal/mol (delta G = 0.9 kcal/mol for AGI and aGI', 1.0 kcal/mol for GAI and GaI', 2.1 kcal/mol for aGI and AGI', and 2.8 kcal/mol for GaI and GAI'; 1 kcal = 4.18 kJ). The delta G value for simultaneous growth of one methyl group at L1 and another at L2 was the sum of the two component delta G values. The delta G values for I-->I' refolding of the common beta-turn conformer into the inverse-common beta-turn conformer ranged over 6 kcal/mol (-3.0 for aa, -1.8 for Ga, -1.1 for aG, -0.7 for Aa, 0 for GG, 0.7 for aA, 1.1 for AG, 1.8 for GA, and 3.0 for AA). Thus, replacing L-Ala by D-Ala at both L1 and L2 of a common beta turn may contribute as much as 6 kcal/mol toward its refolding as an inverse-common beta turn.

[Effects of "he xiang zhuang gongfu" on respiratory function in healthy adults]

Eleven healthy adults who practised He Xiang Zhuang Gongfu (HGF) were followed for 6 months; 15 pulmonary function tests were determined before HGF practice, 2 months and 6 months after HGF practice. All 11 subjects took the HGF exercise every day for 30 minutes. Samplings were taken before subjects had ever practised HGF as control value, immediately and 30 minutes after HGF exercise. In the 2nd month and 6th month of HGF practice. The results indicated that VO2 decreased after 2 and 6 months HGF practice, and the effect even persisted to 30 minutes after HGF exercise, indicating that HGF may reduce metabolic rate and decrease the oxygen consumption of body. The possible mechanism was discussed. MVV had an up tendency after HGF practice, which suggested the possibility of strengthening respiratory muscle by HGF. HGF may be a good physical exercise and can induce a wakeful hypometabolic physiologic state.

Differentiation of Rickettsia japonica by restriction endonuclease fragment length polymorphism using products of polymerase chain reaction amplification with Rickettsia rickettsii 190-kilodalton surface antigen gene primers

Restriction fragment length polymorphism of polymerase chain reaction (PCR) amplification products differentiated Rickettsia japonica, a causative agent of Oriental spotted fever, from other spotted fever group (SFG) rickettsiae. Primer pair Rr190. 70p and Rr190. 602n of R. rickettsii 190-kDa antigen gene sequence primed genomic DNAs obtained from R. japonica, type strain YH and strains NT, NK, YKI, and TKN. The products were cleaved by PstI but not by AfaI restriction endonuclease. The PstI digestion pattern of PCR-products amplified from all strains of R. japonica was identical and easily differentiated from that of other SFG rickettsiae. The present study demonstrated a genotypic difference between R. japonica and other pathogenic SFG rickettsiae.

[The effect of 764-3 on alveolar macrophage morphologic changes induced by BLM-A6]

The morphologic changes of alveolar macrophages (AM) were observed by electron microscopy, computer controlled image analysis and stereoscopy. The results showed that 764-3 had no effect on normal AM morphology and structure, but inhibited the BLM-A6 induced increase of volume, specific surface, and lysosome volume density of AM. At the same time, the spreading ability of AM on the slide was markedly reduced by 764-3, indicating that 764-3 can partially prevent the AM activation caused by BLM-A6 in vitro.

Generation and purification of recombinant fimbrillin from Porphyromonas (Bacteroides) gingivalis 381

Fimbrillin is the major subunit protein of fimbriae from the human periodontal pathogen Porphyromonas (Bacteroides) gingivalis. We describe here the generation and initial characterization of recombinant fimbrillin (r-fimbrillin) isolated from P. gingivalis 381. A fragment of DNA encoding the gene for fimbrillin was generated by polymerase chain reaction and cloned into the expression vector pET11b. Plasmids containing the recombinant gene were transfected into Escherichia coli. Clones were selected on plates for ampicillin resistance and individually screened by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for protein production after activation with IPTG (isopropyl-beta-D- thiogalactopyranoside). One clone, OW0.2, produced significant amounts of a 42-kDa protein after induction with IPTG. This clone contained the pET11b plasmid with a 1-kb insert that had sequence homology to the gene encoding fimbrillin. The majority of recombinant protein from clone OW0.2 was found in the cytoplasm within inclusion bodies. Protein aggregates were solubilized in 8 M urea, and SDS-PAGE analysis showed two major protein bands, one at 42 kDa and the other at 17 kDa. These two proteins coeluted from a DEAE-Sepharose column at 0.15 M NaCl and were reactive to rabbit antiserum to fimbrillin in a Western blot (immunoblot). A preparation giving a single protein band at 42 kDa in SDS-PAGE was obtained by size fractionation by using continuous-elution electrophoresis. Lymph node cells from animals immunized with either fimbrillin from P. gingivalis or r-fimbrillin showed antigen-specific proliferation to both P. gingivalis fimbrillin and r-fimbrillin in an in vitro recall assay. Therefore, it appears that r-fimbrillin is chemically, antigenically, and serologically identical to fimbrillin isolated from P. gingivalis 381.

The role of activated neutrophils and free radical in the pathogenesis of pulmonary hypertension

In in situ perfused rat lungs, it was demonstrated that the perfusing pressure and permeability of pulmonary capillaries were obviously increased after activated neutrophils (PMNs) were added to the perfusate. The effect of free radicals generated by the xanthine-xanthine oxidase system on isolated rabbit pulmonary arterial ring tension was also observed, and the contractile response was found to be dose dependent: The smaller the vessel diameter, the higher the contractile response. Superoxide dismutase and catalase were able to obviously attenuate the contractile response. The response was endothelium independent, and was influenced neither by indomethacin (cyclooxygenase inhibitor) nor by nordihydroguaiaretic acid (lipoxygenase inhibitor), while removal of Ca from the bath solution or addition of the protein kinase C (PKC) inhibitor "H7" or an antiinflammatory drug (764-3, the effective component of Radix Salvia miltiorrhizae) could significantly inhibit the contractile response. The results suggest that activated PMNs may play an important role in the pathogenesis of pulmonary hypertension.

[Study on hydrolytic kinetics of metronidazole-phosphate in rabbit plasma by HPLC]

A HPLC method for the simultaneous determination of metronidazole and metronidazole-phosphate in rabbit plasma has been established. This method is simple, sensitive, reproducible and has a good linearity. It has been used to study the hydrolytic kinetics of metronidazole-phosphate in rabbit plasma. The results show that hydrolytic process of metronidazole-phosphate in vitro at 37 degrees C follows a first order kinetics with the rate constant 0.016 min-1 and half-life 43 min.

Cell- and heparin-binding domains of the hexabrachion arm identified by tenascin expression proteins

We have produced a set of bacterial expression proteins corresponding to 10 segments of tenascin and two of fibronectin and tested them for heparin binding and cell adhesion. We used polymerase chain reaction cloning to terminate the segments precisely at domain boundaries. Heparin binding activity was mapped to two different tenascin segments: one comprising the fourth and fifth fibronectin type III domains, and to TNfbg, the fibrinogen-like terminal knob. TNfbg, but none of the other tanascin segments, also supported adhesion of primary rat embryo skin fibroblasts. The fibroblasts did not spread on TNfbg but remained rounded. Cell binding to TNfbg occurred in the presence or absence of divalent cations and was not inhibited by RGD peptides, suggesting that integrins are not involved. Fibroblast binding to TNfbg was strongly inhibited by soluble heparin, by treating the cells with heparitinase, or by culture conditions that cause undersulfation of proteoglycans. These observations suggest that cell attachment to TNfbg is mediated by cell surface proteoglycans. We have also made full-length cDNA constructs for the largest and smallest splice variants of human tenascin, as well as one truncated after the 14th epidermal growth factor-like domain, in the pNUT mammalian cell expression vector. Stably transfected baby hamster kidney cell lines secreted large quantities of tenascin, and this was assembled into normal hexabrachions, the arm length corresponding to the construct.

[Effect of 764-3 on ConA receptors on rat alveolar macrophages]

The changes of concanavalin A (ConA) receptors on alveolar macrophage (AM) surfaces were observed by means of ConA-horseradish peroxidase gold labelling techniques. The results were as follows: 1) The average gold particle number on normal AM surfaces was 1.985 +/- 0.097/microns, distributed uniformly; 2) On AM activated by BLMA6, in vitro, this number had increased to 3.909 +/- 0.314/microns, P < 0.001 compared with the normal group; 3) On AM preincubated with 764-3, the average gold particle number was 1.577 +/- 0.090/microns, significantly lower than that in the BLMA6 group. All results suggest that 764-3 might partially inhibit the expression of ConA-R on AM activated by BL-MA6.

Retrovirus-mediated transfer and expression of marker genes in the BN rat acute myelocytic leukemia model for the study of minimal residual disease (MRD)

To study minimal residual disease (MRD) in leukemia, we transferred the Escherichia coli genes encoding beta-galactosidase (lacZ) and neomycin resistance (neo(r)) into the subline LT12 of the Brown Norway rat acute myelocytic leukemia (BNML), employing the retroviral BAG vector. In this way leukemic cells were genetically marked. Ten independent cell lines were characterized during in vitro growth as well as during two subsequent in vivo passages for expression of neo(r) for which the neomycin analogue G418 was used, and for lacZ expression for which the substrate 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal) was used. Out of 10 lines, four revealed permanent high expression of lacZ in all cells. In four other lines greatly varying lacZ expression between the individual cells from these lines was observed. In the remaining two lines lacZ expression was gradually lost. In contrast, neo(r) expression was gradually lost in eight out of the 10 lines, particularly rapidly during in vivo passaging. In the remaining two lines neo(r) expression was retained. The genetic modification did not alter the in vitro leukemogenicity of the cells. Long term in vivo expression of neo(r) and lacZ was followed in two selected lines up to 12 subsequent passages, i.e. one from the group of homogeneous high lacZ expression and one from the group of heterogeneous lacZ expression. In both lines lacZ expression was retained whereas neo(r) expression was rapidly lost after the third passage. The feasibility of using genetically marked leukemic cells for studies of minimal residual disease (MRD) was explored by injecting rats with leukemic cells, treating them with chemotherapy at full blown leukemia development to reduce the tumor load, mimicking the induction of a state of MRD and studying lacZ expression at relapse. LacZ expression was evident in 100% of the cells whereas neo(r) expression was lost in a considerable fraction. These results indicate that the viral vector BAG can be used to mark leukemia cells genetically although a selection of clones with the desired stability of long-term expression is required.

An approximation formula for the variance of PET region-of-interest values

An approximation formula for the variance of positron emission tomography (PET) region-of-interest (ROI) values has been developed, implemented, and evaluated. This formula does not require access to the original projection data and is therefore convenient for routine use. The formula was derived by applying successive approximations to the filtered-backprojection reconstruction algorithm. ROI variance is estimated from the product of mean pixel variance within the region and a term accounting for the intercorrelation of all pixel pairs inside the region. The formula accounts for radioactivity distribution, attenuation, randoms, scatter, deadtime, detector normalization, scan length, decay, and reconstruction filter. The algorithm was tested by comparison to the exact ROI variance as calculated with Huesman's algorithm. Tests with scan data from phantoms, animals, and humans obtained on the Scanditronix PC2048-15B tomograph showed the approximation formula to be accurate to within +/-10%

Shift in infrared interference filters at cryogenic temperature

The temperature dependence of the IR interference filters that use lead telluride as a high-index material is measured at various temperatures. Experimental results show that the wavelength and transmission shifts are dominated by the absorption edge and index of refraction of lead telluride, respectively, depending on where the transmission spectrum of the filter is located.

Looking at proteins: representations, folding, packing, and design. Biophysical Society National Lecture, 1992

Looking at proteins is an active process of interpretation and selection, emphasizing some features and deleting others. Multiple representations are needed, for such purposes as showing motions or conveying both the chain connectivity and the three-dimensional shape simultaneously. In studying and comparing protein structures, ideas are suggested about the determinants of tertiary structure and of folding (e.g., that Greek key beta barrels may fold up two strands at a time). The design and synthesis of new proteins "from scratch" provides a route toward the experimental testing of such ideas. It has also been a fruitful new perspective from which to look at structures, requiring such things as statistics on very narrowly defined structural categories and explicit attention to "negative design" criteria that actively block unwanted alternatives (e.g., reverse topology of a helix bundle, or edge-to-edge aggregation of beta sheets). Recently, the field of protein design has produced a rather unexpected general result: apparently we do indeed know enough to successfully design proteins that fold into approximately correct structures, but not enough to design unique, native-like structures. The degree of order varies considerably, but even the best designed material shows multiple conformations by NMR, more similar to a "molten globule" folding intermediate than to a well ordered native tertiary structure. In response to this conclusion, we are now working on systems that test useful questions with approximate structures (such as determining which factors most influence the choice of helix-bundle topology) and also analyzing how natural proteins achieve unique core conformations (e.g., for side chains on the interior side of a beta sheet, illustrated in the kinemages).