Heterogeneous expression of alpha 1-adrenoceptor subtypes among rat nephron segments

alpha 1-Adrenoceptor subtypes mediate many of the actions of the renal nerve, but their locations along the nephron are unknown. We investigated the distribution of alpha 1-adrenoceptor subtype mRNA and protein in rat proximal tubules and medullary thick ascending limbs (MTAL) using reverse transcription combined with polymerase chain reaction (PCR) and radioligand binding methods. Complementary primers were designed to span cDNA sequences in each of the third intracellular loops of the rat alpha 1B- and alpha 1D-adrenoceptors. Expression of the mRNA of alpha 1B- and alpha 1D-adrenoceptors was first detected in total RNA from whole rat kidney, and the PCR product identity was confirmed by sequencing. Endogenous expression of alpha 1B- and/or alpha 1D-adrenoceptor mRNA was then investigated in microdissected segments of the rat proximal convoluted tubule (S2 segments) and the MTAL. mRNA was reverse-transcribed directly from permeabilized microdissected segments and the resulting cDNA was subjected to PCR with the alpha 1-adrenoceptor primers. In proximal convoluted tubules, amplification of both alpha 1B- and alpha 1D-adrenoceptor mRNA was observed. In MTAL segments, only alpha 1D-adrenoceptor mRNA was detected. We also measured receptor protein using [3H]prazosin in saturation and competition binding experiments. Proximal tubular membranes contained 3.3-fold more alpha 1-adrenoceptor than did MTAL membranes (163 +/- 21 versus 49 +/- 3 fmol/mg of protein). When the alkylating agent chloroethylclonidine (CEC) (10 microM, 10 min) was used to define alpha 1-adrenoceptor subtypes, proximal tubules were found to contain primarily CEC-insensitive (alpha 1A) sites (68 +/- 4%) and MTAL primarily CEC-sensitive sites (75 +/- 3%). Most [3H]prazosin binding sites (72 +/- 2%) in MTAL segments were also sensitive to the alkylating agent SZL-49, consistent with their identification as alpha 1D-adrenoceptors. In competition studies with the antagonists WB4101, 5-methylurapidil, and (+)-niguldipine, both high and low affinity sites were observed in proximal tubules. WB4101 interacted with only one site in MTAL membranes, intermediate in affinity between those sites found in proximal tubules. We conclude that reverse transcription-PCR is a useful method for demonstrating the expression of alpha 1-adrenoceptor subtypes in small amounts of tissue. Results from our experiments suggest that alpha 1A-, alpha 1B-, and alpha 1D-adrenoceptors are all expressed in proximal tubules and that alpha 1D-adrenoceptors are the primary alpha 1-adrenoceptor subtype expressed in MTAL. The distinct anatomical distribution of each of these adrenoceptor subtypes suggests that they serve different functions in the kidney.

Brief physical inactivity prolongs colonic transit time in elderly active men

The effects of two weeks of reduced activity on gastrointestinal transit time were studied in nine healthy elderly subjects, who had engaged in regular recreational exercise for ten years. Physical inactivity was achieved by a restriction of all kinds of physical exercise and by staying at home. Mouth-to-cecum transit time was measured by a breath hydrogen method and mean total and segmental colonic transit times by a radiopaque marker method. The mouth-to-cecum transit time did not change during the period of physical inactivity. The mean total colonic transit time (10.9 +/- 2.7 h) was significantly prolonged to 19.5 +/- 2.9 hours during the physical inactivity (p < 0.01). This prolongation was due to slowed transit through the right and the left segments of the colon. The transit time of the rectosigmoid segment of the colon was not affected. In conclusion, the period of physical inactivity prolonged the colonic transit time in active elderly subjects.

Genetic and biochemical analysis of an endonuclease encoded by the IncN plasmid pKM101

The IncN plasmid pKM101 nuc gene encodes a periplasmically localized endonuclease. DNA sequence analysis indicates that this gene encodes a hydrophilic protein of about 19.5 kDa containing a hydrophobic signal sequence. nuc is homologous to a partially sequenced open reading frame adjacent to the sog gene of the plasmid CollB-P9, a plasmid known to encode an endonuclease similar to that of pKM101. A partially sequenced tra gene directly upstream of nuc is homologous to the virB11 gene of Agrobacterium tumefaciens. We have partially purified the pKM101 nuclease by osmotic shock and cation exchange chromatography, and used this enzyme preparation to sequence the protein's amino terminus. The first 13 amino acids of the mature protein match amino acids 23 to 35 of the predicted sequence, indicating that the protein is proteolytically processed to a molecular mass of approximately 17 kDa, probably during export to the periplasmic space. The enzyme was able to attack many sites along an end labelled duplex DNA substrate, but showed clearly preferred cleavage sites, and may cleave preferentially at purine-rich regions.

Human hepatoma cells synthesize and secrete insulin-like growth factor Ia prohormone under growth hormone control

Nucleotide sequencing of cDNAs encoding human insulin-like growth factor I (IGF-I) predicts the existence of two different prohormone forms of IGF-I. The E peptide regions extend the carboxy-terminus of the 70 amino acid core IGF-I molecule (BCAD domains) by either an additional 35 (IGF-Ia) or 77 (IGF-Ib) amino acids. Employing antiserum directed against a peptide sequence unique to the E peptide region of IGF-Ia prohormone, we have identified EIa immunoreactive material (IR-EIa) in the conditioned medium of a human hepatoma cell line, HepG2. Human growth hormone (GH) had dose-dependent stimulatory effects on IR-EIa secretion; incubation of HepG2 cells with GH at maximal concentrations (1-5 micrograms/ml) increased specific IR-EIa in 24 h conditioned medium 3-fold. The addition of human placental lactogen, insulin, IGF-I, dexamethasone, beta-estradiol, or progesterone had no significant effect. Acid chromatography of HepG2 cell conditioned medium revealed a single elution peak of IR-EIa corresponding to M(r) = 12,000-20,000. There was no immunologically detectable 7500 M(r) IGF-I peptide in acid-chromatographed conditioned medium under either basal or stimulated conditions. Biosynthetic labelling of HepG2 cell products with [35S]Trans label and immunoprecipitation with antisera specific to the E or to the AD regions of the IGF-Ia molecule indicated a single species of approx. 14,000 M(r). These data indicate that the E peptide region of IGF-Ia is translated and released as part of the larger molecule in cultured HepG2 cells, and that the levels of this prohormone are regulated by GH.

An upstream promoter element of the Acanthamoeba castellanii TBP gene binds a DNA sequence specific transcription activating protein, TPBF

We have characterized a positive-acting element in the upstream portion of the Acanthamoeba TBP gene promoter. The 27 bp element (TPE), located within the promoter between -97 and -70, stimulates transcription in an orientation independent fashion and tolerates modest changes in its distance from the TATA box. The TPE does not, however, function synergistically nor when positioned 3000 bp 5' or 260 base pairs 3' of the transcription start site. The TPE binds a DNA sequence-dependent factor, TPBF, which we have partly purified. TPBF was characterized using in vitro transcription, DNase I footprinting, methylation interference and electrophoretic mobility shift assays. TPBF does not have a counterpart in HeLa cells, but nonetheless strongly stimulates transcription of the Acanthamoeba TBP gene in mammalian extracts. Our results also suggest that there are additional positively and negatively acting elements within the TBP gene promoter, for which a model is presented.

Production of human cloned antibodies specific for hepatitis D virus-encoded small and large protein

Cloned antibodies to specific epitopes of hepatitis D virus were produced by transformation with Epstein-Barr virus and subsequent cloning of peripheral blood B lymphocytes from a patient with chronic hepatitis D virus infection. Several stable cloned B cell lines, derived from two parent cultures, produced hepatitis D-virus-specific IgG antibodies. Some cloned IgG antibodies detected hepatitis D virus-associated antigen in hepatitis D virus-infected woodchuck liver tissue sections by indirect immunofluorescence staining and some reacted in an inhibition ELISA test detecting hepatitis D virus antibodies; most cloned IgG lines detected hepatitis D antigen both in immunofluorescence tests and in inhibition ELISA. Cloned antibodies to hepatitis D antigen detected by ELISA and/or immunofluorescence staining recognized the two major specific native and denatured polypeptides, p27 and p29, in Western blot analysis. Such cloned antibodies for hepatitis D virus are potentially useful for clinical diagnosis and research.

Detection of the HPV16 E6 transforming gene by PCR in tissue samples from normal cervix and from cervix with precancerous lesions and carcinomas

A study of 130 biopsies from cases of histologically confirmed normal cervix (30), cervicitis (28), cervical intraepithelial neoplasia (CINI-CIN III, 29), and cervical cancer (43) was performed to determine the presence of human papillomavirus (HPV) type 16 DNA sequences. The polymerase chain reaction technique was adopted using two oligonucleotides as primer pairs in the HPV16 early 6 (E6) gene open reading frame (ORF). The rates of HPV16 infection in normal tissues, cervicitis, CINI-CIN III and cervical cancer were found to be 16.67% (5/30), 25.00% (7/28), 41.38% (12/29) and 69.77% (30/43), respectively. Statistical analysis showed that the relative risk (RR) of association between HPV16 infection and the development of cervicitis, CINs and cervical carcinomas was increased with the severity of cervical lesions, from 1.0 (normal) to 1.67, 4.62 (P < 0.05; 95% CI 0.28-8.95) and 11.54 (P < 0.001; 95% CI 3.94-33.81), respectively. Our results strongly support the idea that the development of cervical precancerous lesions and cervical carcinomas is closely associated with HPV16 infection.

Interleukin-10 production by human carcinoma cell lines and its relationship to interleukin-6 expression

Recent data indicate a major role for IL-10 in suppressing immune and inflammatory reactions. To date, expression of human IL-10 has been attributed primarily to helper T lymphocytes, activated monocytes, and neoplastic B cells, and was often found to be associated with IL-6 expression. In this study we sought to determine whether non-hematopoietic human tumor cell lines produce IL-10 and, if so, what is the relationship between IL-10 and IL-6. Using ELISA, we determined IL-10 and IL-6 levels in culture supernatants of 48 cell lines established from carcinomas of the kidney, colon, breast and pancreas, malignant melanomas and neuroblastomas. IL-6 protein was secreted by 28 of the tumor cell lines; IL-10 was measurable in 15 cell lines. IL-6 secretion was maximal and most frequent in renal-cancer cell lines, while IL-10 production was found to be highest and most common among cell lines derived from colon carcinomas. IL-10 in conditioned medium of one of the colon carcinoma cell lines (CCL222) was bio-active, as demonstrated in the mouse MC/9 mast-cell-line assay and in human mixed-lymphocyte reactions. In both assays, IL-10 bio-activity was neutralized by an anti-IL-10 monoclonal antibody. Expression of IL-6 and IL-10 was confirmed by RNA analysis using message amplification by PCR and sequencing of amplified cDNA. LPS, IL-1 alpha, and TNF-alpha strongly enhanced the release of IL-6 by RCC cells, but only marginally affected IL-10 production in colon-carcinoma cells. IL-10 secretion by colon-carcinoma cells was moderately stimulated by IFN-gamma and IL-4. Dexamethasone suppressed the release of IL-6, but had no inhibitory effect on IL-10 secretion. Our results demonstrate that tumor cell lines established from certain types of human carcinomas are capable of expressing and releasing IL-6 and/or IL-10, suggesting a role of these cytokines in solid-tumor development and anti-tumor immunity.

GC/MS identification of tetramine in samples from human alimentary intoxication and evaluation of artificial carbonic kidneys for the treatment of the victims

One day in July 1991, 78 people became victims of accidental alimentary intoxication in a factory in Hebei Province, China. Related samples, including rodenticide bait, the artificial carbonic kidneys used for the treatment of the victims, and the victims' blood, were analyzed by GC/MS. Tetramine [80-12-6], a highly toxic rodenticide, was identified as the toxicant. The effectiveness of artificial carbonic kidneys was evaluated. The analytical results revealed that detoxification of the patients was effective 48 hours after intoxication by percolating their blood through artificial carbonic kidneys.

Characterization of proinsulin-like growth factor-II E-region immunoreactivity in serum and other biological fluids

Insulin-like growth factor-II (IGF-II) purified from human serum consists of 67 amino acids. However, mRNA sequence predicts a long carboxy-terminal extension (E-region), which on translation would yield a bigger IGF-II prohormone than the peptide isolated from serum. A peptide containing the predicted IGF-II prohormone sequence extending from Asp69 to Tyr84 (E-II) was synthesized by the solid state method and used to generate a polyclonal antiserum. Using this E-II antiserum, a specific RIA for IGF-II prohormone forms was developed. [125I]E-II was used as tracer, and synthetic E-II was used for the standard curve. The antiserum was highly sensitive and specific for E-II. It also recognized pro-IGF-II-E21, a 9.8-kilodalton (kDa) synthetic peptide which consisted of IGF-II plus the first 21-amino acid sequence of the IGF-II E-peptide region. Human biological fluids assayed included serum and amniotic, seminal, and cerebral spinal fluids. Sera from patients with chronic renal failure (CRF) and nonislet cell tumor hypoglycemia (NICTH) had the highest levels of E-II immunoreactivity. Amniotic and seminal fluids and acromegalic plasma had intermediate levels. E-II levels in normal, cord, and pregnancy sera were low, but measurable. To further characterize the molecular forms of the apparent E-II immunoreactivity, sera pooled from five normal subjects, five CRF patients, and one patient with NICTH were chromatographed separately over a Sephadex G-50 column in formic acid. With all samples, there was a major peak of E-II immunoreactivity at about 15 kDa, consistent with the predicted size of the IGF-II prohormone. There was a second smaller peak at about 10 kDa in NICTH serum. With CRF serum, there was a prominent peak at 3 kDa, which probably consisted of breakdown products of the IGF-II E-peptide region. The 15-kDa peak was highest in NICTH serum. With all three samples, IGF-I eluted in a single peak at about 7 kDa and was low in NICTH serum. There were two peaks of IGF-II. The first coincided with the peak of E-II at 15 kDa, while the second comigrated with IGF-I. By Western immunoblot analysis, the E-II antiserum detected pro-IGF-II-E21 as a band at 10 kDa, but it did not recognize 7.5-kDa recombinant IGF-II, which did not have the E-peptide region.(ABSTRACT TRUNCATED AT 400 WORDS)

Activating transcription factor-1 can mediate Ca(2+)- and cAMP-inducible transcriptional activation

Increased intracellular cAMP and Ca2+ levels can activate transcription of a number of eukaryotic genes through a common promoter element, the cAMP/Ca2+ response element. This element is the binding site for activating transcription factor (ATF)/CREB proteins, an extensive transcription factor family. Here we report that one member of this family, ATF-1, can mediate both Ca2+ and cAMP transcriptional responses, but that the responses to the two pathways differ in magnitude. In contrast, another family member, CREB, has been shown to mediate Ca2+ and cAMP responses to similar levels. Taken together, these results suggest a mechanism that allows cells to integrate and differentiate gene regulation by cAMP and Ca2+.

Should the photon flux or the photon density be used to describe the temporal profiles of scattered ultrashort laser pulses in random media?

The temporal profiles of ultrashort laser pulses scattered in random media with different experimental geometries were measured and analyzed by using the photon flux and the photon density predicted by the diffusion theory. The scattered laser pulse profiles detected by an optical fiber inside an infinite random medium are found to be described by the photon density. For a semi-infinite medium, the scattered pulse profile emitted from the surface of the medium can be described by either the photon density or the photon flux. These results can be consistently explained by the diffuse intensity (radiance) of transport theory.

Characterization of the protease and other products of amino-terminus-proximal cleavage of the herpes simplex virus 1 UL26 protein

The herpes simplex virus 1 UL26 open reading frame encodes a protease which cleaves a small carboxyl-terminal peptide of itself and its substrate encoded by an overlapping, 3'-coterminal transcriptional unit, designated UL26.5. The translational product of UL26.5 is infected-cell protein 35c,d (ICP35c,d) (F. Liu and B. Roizman, J. Virol. 65:206-212, 1991; F. Liu and B. Roizman, J. Virol. 65:5149-5156, 1991). The protease activity maps at the amino terminus of UL26 translation product designated Pra. Cleavage of Pra to remove the carboxyl-terminal 25 amino acids converts the protein to Prb (F. Liu and B. Roizman, Proc. Natl. Acad. Sci. USA 89:2076-2080, 1992). Other studies reported a second, amino-terminus-proximal cleavage in UL26 gene products made in Escherichia coli (I. C. Deckman, M. Hagen, and P. J. McCann III, J. Virol 66:7362-7367, 1992; C. L. DiIanni, D. A. Drier, I. C. Deckman, P.J. McCann III, F. Liu, B. Roizman, R. J. Colonno, and M. G. Cordingley, J. Biol. Chem., 368:2048-2051, 1993). We report the following results. (i) The amino-terminus-proximal cleavage of UL26 protein in eukaryotic cells generates two polypeptides, an apparent M(r)-25,000 amino-terminal polypeptide designated Prn and a carboxyl-terminal polypeptide which corresponds in electrophoretic mobility to ICP35a. Cleavage of the carboxyl-terminal 25 amino acids by the UL26 protease converted ICP35a to ICP35b. (ii) Replacement of Ala-247-Ser-248 with Arg-Pro precluded the amino-terminus-proximal cleavage. (iii) Prn, the amino-terminal product of the cleavage reaction at amino acid 247 functions as a protease. (iv) Additional amino acid substitutions in the putative domain of the protease yielded results consistent with the hypothesis that UL26 encodes a serine protease. (v) The domain of the UL26 protein whose modification confers the formation of double bands for all products (Pra, Prb, ICP35a, ICP35b, ICP35c,d, and ICP35e,f) except Prn maps in the domain shared by UL26 and UL26.5, between codons 307 and 417.

Spectral optical-density measurements of small particles and breast tissues

The optical density of breast tissues without blood is found to be relatively constant from 320 to 800 nm, indicating a relatively independent scattering cross section over this wavelength region.

Characterization of insulin-like growth factor binding protein-3 in chronic renal failure serum

IGF-binding protein-3 (IGFBP-3), usually found as glycosylated 41- and 38-kD forms, is the major serum IGFBP during extrauterine life. In normal serum IGFBP-3 binds one IGF peptide and one acid-labile (alpha) subunit in a high-molecular-weight (MW) complex of 150 kD. By RIA, an excess of IGFBP-3 is present in chronic renal failure (CRF) serum, where it reportedly accumulates at low MW (25-55 kD) rather than as part of the 150-kD complex. To further evaluate IGFBP-3 forms in CRF, sera were obtained from seven healthy adolescents and seven adolescents with CRF. By RIA, IGFBP-3 levels were higher in CRF than normal sera (15.4 +/- 2.2 versus 10.1 +/- 2.1 micrograms/mL). High-MW (150-kD) fractions of CRF and normal sera, obtained by neutral size-exclusion chromatography, had equal amounts of IGFBP-3 by RIA. However, a second RIA peak of IGFBP-3, present in low-MW (35-kD) fractions of CRF but not normal sera, could account for the higher IGFBP-3 levels of CRF serum. [125I]IGF ligand blots of whole serum and serum fractions, either with or without prior precipitation by IGFBP-3 antiserum, found levels of 41- and 38-kD IGFBP-3 forms to be similar between CRF and normal whole sera and located these forms in the high-MW (150-kD) fractions of CRF and normal sera.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrafast laser-pulse transmission and imaging through biological tissues

The transmission of 100-fs ultrafast laser pulses through biological tissues was measured by using femtosecond and picosecond time-resolved detection techniques. The broadening of transmitted pulses was found to increase as the thickness of the biological tissue increases. The absence of a distinct ballistic pulse transmitted through a relatively thin tissue is in sharp contrast with the pulse transmission through a random medium of discrete scatterers. Because of the continuous variation of the dielectric constant in tissue, the photons undergo scattering through the tissue, travel in various small zigzag least optical paths, and form a broadened early-arriving portion of the transmitted pulse. Even in the absence of a well-defined ballistic pulse, we can image an opaque object hidden inside a tissue as thick as 6.5 mm with submillimeter resolution by selecting the early-arriving portion of the transmitted pulse.

Identification of the herpes simplex virus-1 protease cleavage sites by direct sequence analysis of autoproteolytic cleavage products

Herpes simplex virus type-1 (HSV-1) encodes a protease responsible for proteolytic processing of the virus assembly protein, ICP35 (infected cell protein 35). The coding region of ICP35 is contained within the gene that encodes the protease, and ICP35 shares amino acid identity with the carboxyl-terminal 329 amino acids of the protease. The HSV-1 protease was expressed in Escherichia coli as a fusion protein containing a unique epitope and the protein A Fc binding domain at its carboxyl terminus. The fusion protease underwent autoproteolytic cleavage at two distinct sites. The size of the cleavage products containing the carboxyl-terminal epitope mapped one cleavage site near the carboxyl terminus of the protease corresponding to the proteolytic processing site of ICP35, and the second site proximal to the amino terminus consistent with previous data. The carboxyl-terminal autoproteolytic cleavage products were partially purified on an IgG affinity column by virtue of the protein A Fc binding domain and subjected to direct amino-terminal sequence analysis. Protein sequencing revealed that cleavage occurs between the Ala and Ser residues at amino acids 610/611 and 247/248 of the HSV-1 protease. The flanking sequences share homology with each other and are highly conserved in homologous proteases of other herpes viruses.

Measurement and characterization of insulin-like growth factor binding protein-3 in human biological fluids: discrepancies between radioimmunoassay and ligand blotting

The inability to detect insulin-like growth factor binding protein-3 (IGFBP-3) in some circumstances by Western ligand blot analysis has emphasized the need to characterize IGFBPs by both ligand binding and immunological techniques. In this study, we have: 1) characterized and quantified IGFBP-3 in nonpregnancy, pregnancy, and fetal cord serum, follicular, peritoneal, and amniotic fluid, seminal plasma, cerebrospinal fluid (CSF), and urine; 2) established a new IGFBP-3 RIA that detects both intact and fragments of IGFBP-3; 3) identified both intact and fragments of IGFBP-3 by Western immunoblot techniques; and 4) addressed the discordance between Western ligand blot analysis and RIA by assessing fluids for IGFBP proteolytic activity. All fluids examined, except pregnancy serum, CSF, and amniotic fluid, displayed a 44-34-kilodalton (kDa) IGFBP-3 doublet by Western ligand blot analysis. Western immunoblot analysis using specific IGFBP-3 antiserum showed a 44-34-kDa IGFBP-3 doublet and a 28-kDa fragment in nonpregnancy serum, fetal cord serum, follicular fluid, and peritoneal fluid. The immunoreactive 42-38-kDa doublet was faint in urine and seminal plasma. IGFBPs in CSF did not cross-react with IGFBP-3 antiserum. Pregnancy serum and amniotic fluid contained only the 28-kDa fragment when compared against equal volumes of nonpregnancy serum. With the development of an IGFBP-3 RIA, IGFBP-3 could be accurately measured; urine, CSF, and seminal plasma contained the lowest levels of IGFBP-3 at 27 +/- 3 ng/ml (mean +/- SEM), 110 +/- 26 ng/ml, and 209 +/- 56 ng/ml, respectively. In increasing concentration: fetal cord serum contained 753 +/- 101 ng/ml; peritoneal fluid, 1124 +/- 130 ng/ml; follicular fluid, 2356 +/- 211 ng/ml; nonpregnancy serum, 3556 +/- 508 ng/ml; pregnancy serum, 3718 +/- 842 ng/ml; and amniotic fluid, 5150 +/- 688 ng/ml. The measurable concentrations of IGFBP-3 in CSF and the high concentrations measured in pregnancy serum and amniotic fluid conflicted with Western blot analysis. Thus, fluids were assessed for IGFBP proteolytic activity by incubation with a source of IGFBP-3, either nonpregnancy serum or purified IGFBP-3. All fluids displayed some proteolytic activity with either assay. Fluids with little protease activity (nonpregnancy serum, follicular fluid, and urine) showed a close relationship between immunoassayable IGFBP-3 by RIA and IGFBP-3 band intensity by Western ligand blot. Fluids with high proteolytic activity (pregnancy serum, CSF, seminal plasma, peritoneal fluid, and amniotic fluid) gave discrepant IGFBP-3 values between RIA and Western ligand blot.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of the high molecular weight insulin-like growth factor complex in term pregnancy serum

Insulin-like growth factors (IGFs) circulate in human adult serum predominantly as a high mol wt complex of 150 kilodaltons (kDa), which is made up of three subunits: alpha, the acid-labile subunit, a glycoprotein of around 85-100 kDa; beta, the acid-stable IGF-binding protein subunit, which is the 40-kDa GH-dependent glycoprotein IGF-binding protein-3 (IGFBP-3); and gamma, the 7.5 IGF-I or -II peptide subunit. During human pregnancy, all three subunits are elevated when measured by RIA. However, recent ligand blotting studies have shown that IGFBP-3 is markedly reduced during pregnancy. When pregnancy serum is acidified and neutralized to inactivate endogenous alpha-subunit, ternary complex formation is normal with exogenous radiolabeled alpha-subunit, indicating functional IGFBP-3. We have attempted to clarify the status of IGFBP-3 and the high mol wt (alpha beta gamma) complex in human term pregnancy serum by further analyses. Term pregnancy (TP) or nonpregnancy (NP) pooled sera were fractionated on a S-300 neutral column. The high mol wt (125-150 kDa) and the low mol wt (30-40 kDa) IGF-IGFBP complexes were identified by both RIA for IGFBP-3 and ligand blotting; each was pooled separately. Half of each pool was lyophilized and rechromatographed in acid to separate the IGF-I peptides from their IGFBPs. The IGFBP fractions were recovered for further studies. When the IGFBPs from the high mol wt complex were cross-linked to [125I]IGF-I or -II, bands of 48, 34, 26, and 21 kDa, which were more intense with [125I]IGF-II, were observed, and all were immunoprecipitable by anti-IGFBP-3 antibody. The smaller forms were elevated in TP serum. Affinity cross-linking analysis with [125I]alpha-subunit showed that the IGFBPs from the high mol wt, but not the low mol wt, complex can reform the ternary 150-kDa complex when cold IGF-I or IGF-II is added exogenously. A smaller 130-kDa complex was also present, and it was the predominant form in TP serum. Both bands were immunoprecipitable by anti-IGFBP-3 antibody. When purified alpha-subunit or fractions from neutral Sephacryl S-300 chromatography were cross-linked to covalent [125I]IGF-II:IGFBP-3, a specific band at 150 kDa was observed with pure alpha-subunit as well as with S-300 150- to 100-kDa serum fractions. These results suggest that 1) functional alpha-subunit is present in TP serum; 2) intact as well as smaller fragments of IGFBP-3 are present in the big complex of TP serum and are able to bind IGF and complex with alpha-subunit; and 3) IGFBP-3 in TP serum has reduced binding to [125I]IGF-I, but not to [125I]IGF-II.

Acanthamoeba castellanii RNA polymerase II transcription in vitro: accurate initiation at the adenovirus major late promoter

We have developed and characterized an efficient in vitro system from the protozoan, Acanthamoeba castellanii, that accurately initiates transcription from the adenovirus-2 major late promoter (AdMLP). Transcription by A. castellanii RNA polymerase II (pol II) is initiated at the same nucleotide (nt) that is used by HeLa extracts and is dependent upon adenovirus sequences located between nt -51 and the region around the transcription start point (tsp). The results suggest that the A. castellanii transcription factors for pol II which determine the tsp and the promoter elements that they recognize have been functionally conserved during evolution.

Isolation of genomic DNA encoding transcription factor TFIID from Acanthamoeba castellanii: characterization of the promoter

We have isolated a genomic clone encoding Acanthamoeba castellanii TFIID. The clone contains the entire TFIID gene, 300 bp of 5' promoter sequences and several hundred base pairs of 3' non-coding sequence. The coding region is interrupted by two short introns, but is otherwise identical to Acanthamoeba TFIID cDNA. Comparisons between forty four Acanthamoeba intron 5' and 3' boundaries suggest a 5' splice site consensus of GTACG(T/C) and a 3' consensus of CAG. We determined the position of the transcription initiation site used in vivo, and show that the same site is used in vitro by homologous nuclear extracts. Deletion analysis of the promoter region shows that the minimal promoter required for efficient expression in vitro is located between -97 and +4 relative to the transcription start site. Three regions within the promoter are important for transcription in vitro; sequences between -97 and -35, the TATAAA box and the initiation region. The initiation region is dispensable but appears to position the transcription start site relative to the TATAAA box. The TATAAA box is absolutely required for transcription initiation whereas the upstream region stimulates transcription approximately five-fold.

[Experimental studies of lung lesions in rabbits caused by Streptomyces thermohygroscopicus]

Imitating the natural way of infection of Farmer's lung disease, we succeeded in inducing acute lesions of Farmer's lung disease in rabbits by the dry powder of thermohygroscopicus. Histopathological examination revealed typical interstitial pneumonitis, alveolitis and bronchiolitis. One week after the inhalation of the dry powder of thermohygroscopicus, the precipitins could be detected in the rabbits' serum by immunoblotting. Depending on the lung lesions of rabbits, we discussed the pathogenetic mechanisms of Farmer's Lung.

Cloning and expression of the Acanthamoeba castellanii gene encoding transcription factor TFIID

We have cloned and characterized the cDNA encoding transcription factor TFIID from the eukaryote, Acanthamoeba castellanii. The gene occurs as a single species, encodes one mRNA and, presumably, a single protein. A. castellanii TFIID contains two recognizable domains, a nonconserved N-terminal domain and a highly conserved C-terminal domain. Similarities between the amino acid (aa) sequences of TFIID from several organisms are also found within the N-terminal 78 aa, suggesting a potential role in TFIID function. Full-length or truncated A. castellanii TFIID produced in Escherichia coli binds to a TATA box and is able to activate transcription in a TFIID-depleted HeLa cell extract, but the C-terminal 180-aa domain was found to be less efficient in these reactions.

Failure of pulmonary acidosis to increase respiratory drive

Experiments were performed to determine whether increases in acidity isolated to the pulmonary circulation would stimulate hypothesized pulmonary chemoreceptors and increase respiratory drive in the anesthetized paralyzed mechanically ventilated cat (n = 9). Respiratory drive was assessed by measuring the frequency and amplitude of the integrated phrenic neurogram. To create an isolated pulmonary acidosis, blood returning to the lung was acidified by infusion of 0.3 M lactic acid (1.91 ml/min) into the inferior vena cava, while systemic arterial pH was restored to near normal levels by simultaneous infusion of base (0.3 M NaOH) into the left atrium. Six minutes after the start of this dual infusion of acid and base, right ventricular (pulmonary) pH decreased from 7.286 to 7.179 and PCO2 increased 7 Torr. Systemic arterial pH and PCO2 were unchanged from measurements immediately before the infusion. This level of pulmonary acidosis failed to increase respiratory drive as assessed by phrenic activity. To test the sensitivity of the preparation to known systemic arterial chemical stimuli, a combined pulmonary and systemic acidosis was elicited by infusion of 0.3 M lactic acid into the inferior vena cava and 0.3 M NaCl into the left atrium. This infusion significantly lowered both systemic arterial and pulmonary arterial pH (7.343 to 7.155 for systemic arterial pH and 7.286 to 7.067 for pulmonary pH) and increased phrenic efferent activity 45%. We conclude that phrenic efferent activity is unaffected by moderate reductions in the pH of the pulmonary circulation in the absence of a significant systemic arterial acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Retinoblastoma gene product activates expression of the human TGF-beta 2 gene through transcription factor ATF-2

The retinoblastoma susceptibility gene product (pRb) plays an important role in constraining cellular proliferation and in regulating the cell cycle. The pRb inhibits transcription of genes involved in growth control (reviewed in ref. 3) and can regulate transforming growth factor beta 1 (TGF-beta 1) gene expression. TGF-beta isoforms also down-regulate cellular proliferation. To determine whether pRb also regulates expression of other TGF-beta isoforms, we examined the effect of pRb on the expression of the human TGF-beta 2 gene. The human TGF-beta 2 promoter contains multiple elements including an ATF site, which is essential for basal promoter activity. Here we report that pRb activates transcription of the human TGF-beta 2 gene. The promoter element responsible for pRb-mediated transcriptional regulation is a binding site for ATF proteins, an extensive transcription factor family. We provide evidence that implicates ATF-2 in pRb-responsiveness. First, the ATF promoter element in the TGF-beta 2 gene is a high-affinity ATF-2-binding site. Second, a GAL4-ATF2 fusion protein can support pRb-mediated transcriptional activation of a promoter containing GAL4-binding sites. Third, ATF-2 in nuclear extracts can interact with pRb. Our results reveal a new mechanism by which pRb constrains cellular proliferation: by activating expression of the inhibitory growth factor, TGF-beta 2.

Effect of pretreatment with epoxy compounds on the mechanical properties of bovine pericardial bioprosthetic materials

Early failures of bovine pericardial heart valves are due to leaflet perforation, tearing and calcification. Since glutaraldehyde fixation has been shown to produce marked changes in leaflet mechanics and has been linked to development of calcification, bovine pericardium fixed with the four hydrophilic epoxy formulations and their mechanical properties are studied in this paper. We measured the thicknesses, shrinkage temperatures, stress relaxations and stress-strain curves of bovine pericardiums after different treatments with (1) non-treatment (fresh), (2) glutaraldehyde (GA), (3) epoxy compounds followed by the posttreatment with GA (EP 1#, EP 2#), and (4) epoxy compounds (EP 3# and EP 4#). Results of this study showed that the hydrophilic epoxy compounds are good crosslinking agents. There are no significant differences of shrinkage temperature and ultimate tensile stress among all tissue samples pretreated with GA, EP 1# and EP 2#. However, the stress relaxations of tissue-samples pretreated with epoxy compounds followed by the posttreatment with GA (EP 1# and EP 2#) are significantly slower than that pretreated with GA, and the strains at fracture of EP 1# and EP 2# are also significantly larger than that of GA or epoxy compounds. These facts show that the bovine pericardium pretreated with the epoxy compound followed by the posttreatment with GA (EP 1# and EP 2#) possesses greater tenacity and potential durability in dynamic stress.

Effect of capsaicin and resiniferatoxin on peptidergic neurons in cultured dorsal root ganglion

The neurotoxic effect of capsaicin has been shown to be selective on a subpopulation of small dorsal root ganglion neurons in newborn animals. The aim of this study was to provide evidence of the long lasting effect of capsaicin and its ultrapotent analog resiniferatoxin (RTX) on sensory peptidergic neurons maintained in organotypic cultures. The effects of the two irritants were examined on neurons that contained substance P (SP) and calcitonin gene-related peptide (CGRP). Exposure of the cultures to 10 microM capsaicin and 100 nM RTX for periods of 2 days or longer resulted in almost complete elimination of SP-immunoreactive (IR) neurites and reduction, but not elimination, of CGRP-IR neurites. In addition, both 10 microM capsaicin and 100 nM RTX significantly reduced the number of SP- and CGRP-IR cell bodies within DRG explants. Capsaicin in 100 microM concentration produced complete elimination of SP-IR fibers and a greater decrease in the number of CGRP-IR fibers, but failed to completely eliminate IR cell bodies. Exposure of the cultures to the irritants in the same concentrations for 90 min did not produce a measurable effect on SP- or CGRP-IR in neurites or cell bodies. It is important to establish that the effect of capsaicin and RTX on cultured neurons was of long duration (longer than 4 days) and is therefore different from depletion of peptides. These findings demonstrate that processes of cultured sensory neurons are much more sensitive to capsaicin and RTX than cell bodies. Furthermore, our results show that SP-IR neuronal elements are more sensitive to capsaicin than CGRP-IR elements. These data suggest that cultured sensory neurons express the functional properties of differentiated sensory neurons in vivo.

[Quality of dihuang (Rehmannia spp.)]

In this paper, the contents of catalpol, water-extract and alcohol-extract materials, ash, total reducing sugar and inorganic elements in Dihuang from different habitats have been measured. The result shows that Huai Dihuang, the genuine drug, excels all those from other habitats in quality. The quality of commercial dry Dihuang may be related closely to the production area, storage time, etc.

Thromboxane A2 mimetic, U46,619, and slowly adapting stretch receptor activity in the rabbit

The effect of infusing the thromboxane A2 mimetic U46,619 on afferent activity from slowly adapting airway stretch receptors (SARs) in the anesthetized rabbit was examined in these experiments. SAR vagal afferent fibers (n = 29) were identified by their slow adaptation to a sustained (10-15 s duration) lung inflation in the closed-chest, mechanically ventilated animal (n = 16). Intravenous infusion of U46,619 increased the discharge frequency of the SAR, measured at the end of inspiration, in a dose-dependent manner: by 6.6% and 8.0% at doses of 0.1 and 0.5 microgram of U46,619/kg, respectively. This increase in SAR activity was correlated with increases in end-inspiratory tracheal airway pressure (6.4% at 0.1 micrograms/kg and 9.1% at 0.5 micrograms/kg). Higher doses of U46,619 could not be administered due to decreases in systemic arterial blood pressure. The increase in SAR activity and tracheal airway pressure was qualitatively comparable to the response to histamine (25 micrograms/kg), a known bronchoconstrictor. We conclude that intravenous infusion of U46,619 in the anesthetized rabbit at doses that elicit significant hemodynamic effects causes modest bronchoconstriction and comparable increases (less than 10%) in SAR afferent nerve activity. From these data, it appears that U46,619 has no direct effect on SARs, but rather increases SAR activity due to bronchoconstriction.

Differentiation of multiple domains in the herpes simplex virus 1 protease encoded by the UL26 gene

Previous studies have shown that the herpes simplex virus 1 gene UL26 encodes a 635-amino acid protease that cleaves approximately 20 amino acids from the carboxyl terminus of itself and of a 329-amino acid product of the UL26.5 gene. The results of studies with a variety of protease inhibitors showed that the UL26 protease was inhibited by serine protease inhibitors but not by inhibitors of cysteine protease, aspartic acid protease, or metalloprotease. Mutations resulting in amino acid substitutions, deletions, or insertion of stop codons in the gene or of 20-amino acid stretches into the protease have delineated the dispensable domains I and IV at the amino and carboxyl domains of the gene product. The essential carboxyl-proximal domain (III) can be separated from the essential amino-proximal domain (II) by at least 20 amino acids. The amino-proximal domain is the most conserved region among varicella-zoster virus and human cytomegalovirus homologues of UL26. Of the conserved aspartic acid, histidine, or serine amino acids in this domain, only histidine-61 and -148 could not be replaced without impairment of the proteolytic activity.

Site-directed mutagenesis of the phosphate-binding consensus sequence in Escherichia coli adenylosuccinate synthetase

Adenylosuccinate synthetases from different sources contain an N-terminal glycine-rich sequence GDEGKGK, which is homologous to the conserved sequence GXXXXGK found in many other guanine nucleotide-binding proteins or enzymes. To determine the role of this sequence in the structure and function of Escherichia coli adenylosuccinate synthetase, site-directed mutagenesis was performed to generate five mutant enzymes: G12V (Gly12----Val), G15V (Gly15----Val), G17V (Gly17----Val), K18R (Lys18----Arg), and I19T (Ile19----Thr). Comparison of the kinetic properties of the wild-type enzyme and those of the mutant enzymes revealed that the sequence is critical for enzyme activity. Replacement of Gly12, Gly15, or Gly17 with Val, or replacement of Lys18 with Arg, resulted in significant decreases in the kcat/Km values of the enzyme. Because the consensus sequence GXXXXGK(T/S) has been found in many GTP-binding proteins, isoleucine at position 19 in the E. coli adenylosuccinate synthetase was changed to threonine to produce the sequence GDEGKGKT. This mutation, which more closely resembles the consensus sequence, resulted in a 160-fold increase in the Km value for substrate GTP; however, there were no great changes for the other two substrates, IMP and aspartate. Based on these data, we suggest that the N-terminal glycinerich sequence in E. coli adenylosuccinate synthetase plays a more important role in enzyme catalysis than in substrate binding. In addition, a hydrophobic amino acid residue such as isoleucine, leucine, or valine, rather than threonine, may play a critical role in GTP binding in adenosuccinate synthetase. These findings suggest that the glycine-rich sequence in adenylosuccinate synthetase functions differently relative to those in other GTP binding proteins or enzymes.

Molecular analysis of Xenopus laevis SPARC (Secreted Protein, Acidic, Rich in Cysteine). A highly conserved acidic calcium-binding extracellular-matrix protein

SPARC (Secreted Protein, Acidic, Rich in Cysteine) is expressed as a 1.6 kb mRNA in Xenopus laevis. On the basis of cDNA sequence analysis, Xenopus SPARC has a core Mr of 32643, with one potential N-glycosylation site. Western analysis of SPARC isolated from Xenopus long bone indicates that the mature protein has an Mr of 43,000. At the amino acid level, Xenopus SPARC has 78-79% sequence similarity to mouse, bovine and human SPARC. The least-conserved region is found within the N-terminal glutamic acid-rich domain, with the C-terminal Ca(2+)-binding domain being the most conserved. Adult Xenopus tissues show the same pattern of tissue-specific distribution of SPARC mRNAs as adult mouse.

[Suppressive effects of safflower yellow on immune functions]

Safflower yellow (SY) extracted from Carthamus tinctorius L contained chalconoid compounds, 75% of which was safflomin A. SY ip 50-450 mg.kg-1.d-1 x 6-8 d in mice decreased serum lysozyme concentration and phagocytosing functions of both peritoneal macrophages and peripheral leukocytes; diminished the production of plaque forming cells, specific rosette forming cells, and antibody; inhibited delayed type hypersensitivity reaction and the activation of T suppressor cells elicited by supraoptimal immunization. Experiments in vitro showed inhibitory effects on [3H]TdR incorporation during human peripheral T- and B-lymphocyte proliferation by SY 0.03-3.0, 0.1-2.0 mg.ml-1 respectively, murine mixed lymphocyte culture response and the production of interleukin-2 by SY 0.1-2.5 mg.ml-1. In conclusion, SY produced declines in both nonspecific and specific immune functions.

[Assessment of induced noninvasively postextrasystolic potentiation on the right ventricular function in patients with cor pulmonale]

The indices of postextrasystolic potentiation degree (Rpesp: Rcdz/dt, RHI, delta Q-Zc, delta PEP/RVET) were observed in the patients with cor-pulmonale, chronic obstructive pulmonary disease (COPD) and normal subjects using extrasystole induced by transesophageal atrial pacing combined with differential impedance rheopneumography. The results shows that Rpesp of the patients with cor-pulmonale was larger than that of the patients with COPD and the normal subjects. The positive rates of RCdz/dt, RHI, delta Q-Zc, delta PEP/RVET was detected respectively in 95%, 100%, 85%, 85% of the cor-pulmonale and in 60%, 60%, 70%, 60% in COPD. It suggested that this method be a safe, simple and reliable one to assess right ventricular contraction function and to diagnose early cor-pulmonale.

[Sedative chemical constituents of leaves of Apocynum venetum Linn]

Eight constituents were isolated from the ether solvent fraction of leaves of Apocynum venetum and identified as triacontanol, beta-sitosterol, quercetin, hyperin, long-chain fatty acids (C28-C34), lupeol, scopoletin and isofraxidin. Isofraxidin and hyperin were effective sedative components.