Chromosomal evolution of the Chinese muntjac (Muntiacus reevesi)

The aim of this study was to test the validity of the hypothesis that the 2n=46 karyotype of the Chinese muntjac (Muntiacus reevesi) could have evolved through 12 tandem fusions from a 2n=70 hypothetical ancestral karyotype, which is still retained in Chinese water deer (Hydropotes inermis) and brown-brocket deer (Mazama gouazoubira). Combining fluorescence-activated chromosomal sorting and degenerate oligonucleotide-primed polymerase chain reaction, we generated chromosome-specific DNA paint probes for 13 M. gouazoubira chromosomes and most of the M. reevesi chromosomes with the exception of 18, 19 and X. These paint probes were used for fluorescence in situ hybridisation to chromosomal preparations of M. reevesi, H. inermis and M. gouazoubira. Chromosome-specific paint probes from M. reevesi chromosomes 1-5 and 11 each delineated more than one homologous pair (18 pairs in total) on the metaphases of H. inermis and M. gouazoubira. All the other probes from M. reevesi and probes from M. gouazoubira each hybridised to one pair of homologous chromosomes or regions. The C5 probe, derived from centromeric satellite sequences of M. reevesi, hybridised to the centromeric regions of all chromosomes of these three species. Most interestingly, several non-random interstitial signals, which are apparently localised to the putative fusion points, were found on chromosomes 1-5 and 11 of M. reevesi. Both the reciprocal painting patterns and localisation of the C5 probe demonstrate that M. reevesi chromosomes 1-5 and 11 could have evolved from 18 different ancestral chromosomes through 12 tandem fusions, thus providing direct molecular cytogenetic support for the tandem fusion hypothesis of karyotype evolution in M. reevesi.

[One-day bowel cleaning for colorectal surgery]

A modified one-day preoperative bowel cleaning was used in patients undergoing surgery for colorectal cancers. It was compared with traditional three-day bowel preparation, 48 patients without obstruction were randomized to two groups, with 24 each. Modified one-day method was used in experimental group, and traditional three-day method was used in control group. No significant changes were found in plasma electrolytes, hemoglobin end hematocrit in both groups. The intraoperative bowel cleaning condition were grade I in all patients. Bowel fluid culture was positive in 30% of the experimental patients, whereas in 70% of the contral patients. Wound infection occurred in one patient in both groups (4.2%). It is suggested that the modified one-day preoperative bowel preparation may alleviate the patients' suffering from diahrrea and homeostatic disturbances, ensure them in good sleep and rest, reduce the nursing work, and result in good bowel cleaning for operation. It is a simple, safe, and effective method for preoperative bowel cleaning.

A reappraisal of the tandem fusion theory of karyotype evolution in Indian muntjac using chromosome painting

We have tested the tandem fusion hypothesis of the origin of the Indian muntjac karyotype (2n = 6/7) by using reciprocal chromosome painting between the Indian muntjac, Chinese muntjac (n = 46) and brown brocket deer (2n = 70 + 3B) with chromosome-specific paint probes derived from flow-sorted chromosomes of these three deer species. Our results have shown that the euchromatic blocks of all chromosome arms of the brown brocket deer have been conserved apparently unchanged in number and content in the Indian muntjac. While confirming the conservation in toto of most of Chinese muntjac euchromatin in the karyotype of the Indian muntjac, we demonstrate that the synteny of chromosomes 1, 2, 3, 4 and 5 of the Chinese muntjac has been disrupted by chromosome rearrangements other than fusions. This indicates that the present karyotype of the Indian muntjac cannot be reconstructed from the hypothetical Chinese muntjac-like 2n = 46 ancestral karyotype exclusively by chromosome fusions. Furthermore, we have shown that the breakpoints of these rearrangements appear to have occurred near to the fusion points formed during the origin of the 2n = 46 karyotype of the Chinese muntjac from a 2n = 70 karyotype, which is believed to be ancestral for the family Cervidae. Moreover, we substantiate that on the Indian muntjac chromosomes, the C5 probe, which is derived from the centromeric satellite sequences of the Chinese muntjac, maps to the putative fusion points determined by comparative chromosome painting and presumably represents the remnants of ancestral centromeric sequences.

Supplemental phytases of microbial and cereal sources improve dietary phytate phosphorus utilization by pigs from weaning through finishing

This experiment was conducted to measure the nutritional and metabolic responses of pigs fed diets with continuous supplementation of microbial and cereal phytase from weaning to finishing, and to determine the feasibility of complete replacement of inorganic P addition by supplemental phytase in swine diets. Forty-eight Landrace x Hampshire x Meishan pigs were divided into four groups. In phase 1 (10 to 50 kg BW), pigs in Groups 1, 2, 3, and 4 were fed a low-P, corn-soybean meal basal diet (BD), the BD plus microbial phytase (A. ficuum) at 1,200 units/kg, the BD plus 10% wheat bran (230 units of cereal phytase/kg), and the BD + .24% inorganic P (calcium phosphate), respectively. In phase 2 (51 to 90 kg BW), these pigs were fed a similar BD or the BD plus 1,000 microbial phytase units/kg, 20% wheat bran, or .20% inorganic P, respectively. Repeated measures included growth performance, P, Ca, and N balance, metatarsal and metacarpal bone strength, serum concentration of inorganic P, Ca, and 1,25-dihydroxycholecalciferol, and serum alkaline phosphatase activity. Pigs fed the BD supplemented with microbial phytase and pigs fed the BD supplemented with inorganic P showed almost identical responses for all variables. Pigs fed the BD supplemented with cereal phytase also had responses for various measures that were similar to those of pigs fed microbial phytase or inorganic P, except for some differences in serum inorganic P concentrations and bone strength in phase 1. Because of improvements in apparent digestibility of dietary P and N, fecal excretion of these two nutrients was reduced by 31 to 62% (P < .05) in pigs fed the BD supplemented with phytase compared with pigs fed inorganic P. It is physiologically feasible and environmentally advantageous to replace inorganic P with microbial or cereal phytase in corn-soybean meal diets for this type of pig through the entire growing-finishing period.

Effects of reducing reagents and temperature on conversion of nitrite and nitrate to nitric oxide and detection of NO by chemiluminescence

To measure the concentration of nitrites and nitrates by chemiluminescence, we examined the efficiency of five reducing agents [V(III), Mo(VI) + Fe(II), NaI, Ti(III), and Cr(III)] to reduce nitrite (NO2-) and (or) nitrate (NO3-) to nitric oxide (NO). The effect of each reducing agent on the conversion of different amounts of NO2- and (or) NO3- (100-500 pmol, representing concentrations of 0.4 to 2 mu molar) to NO was determined at 20 degrees C for NO2- and at 80 degrees C for NO3-. The effect of temperature from 20 to 90 degrees C on the conversion of a fixed amount of NO2- or NO3- (400 pmol or 1.6 mu molar) to NO was also determined. These five reducing agents are similarly efficient for the conversion of NO2- to NO at 20 degrees C. V(III) and Mo(VI) + Fe(II) can completely reduce NO3- to NO at 80 degrees C. NaI and Cr(III) were unable to convert NO3- to NO. Increased temperature facilitated the conversion of NO3- to NO, rather than that of NO2- to NO. We evaluated the recovery of NO2- and NO3- from plasmas of pig and of dog. Recovery from plasma of both animals was reproducible and near quantitative.

[Application of serum bile acid chromatography to the diagnoses of liver diseases]

In order to explore the specificity of serum bile acid (SBA) chromatograph in the diagnoses of different kinds of hepatosis, we investigated by means of gas chromatography the changes of serum bile acids in workers who exposed to hexogen or chloroethylene and in patients who suffered from hepatosis such as acute jaundice hepatitis, chronic active hepatitis, cirrhosis and liver cancer. The results revealed different disturbances of SBA occurring in the liver injuries induced by the two kinds of hepatotoxicant. Serum lithocholic acid (LCA), deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) in workers exposed to hexogen and wre significantly different from those of the control group respectively (P < 0.01, P < 0.01, P < 0.05); on the other hand, only serum LCA and DCA went up in workers exposed to chloroethylene (P < 0.0005, P < 0.001). The main changes both concentrated on the secondary bile acids. In acute jaundice hepatitis, chronic active hepatitis, cirrhosis and liver cancer, serum LCA, DCA, CDCA and cholic acids (CA) all went up in different degrees compared with the control group respectively (P < 0.005, P < 0.025, P < 0.005, P < 0.005). But no difference was noted among the 4 kinds of bile acids (P > 0.5), except that between CA and CDCA. These provided the evidence of the diagnosis and identification of clinical hepato-biliary diseases and occupational liver injures.

Cellular response and membrane formation on the surface of implanted posterior chamber intraocular lens in rabbit

PURPOSE

In order to study the cellular response and membrane formation on the surface of intraocular lens after cataract surgery and lens implantation, this study was designed to observe the deposits on the surface of implanted posterior chamber intraocular lens (PC-IOL) for 4, 7, 15, 30 and 90 days in rabbits.

METHODS

30 rabbits had undergone ECCE with PC-IOL implantation. PC-IOLs were removed at different stages after operation. 20 PC-IOLs were stained by HE to demonstrate cells on the surface of PC-IOL under light microscopy. 5 PC-IOLs for scanning electron microscopy were observed. 5 membranes were studied by transmission electron microscopy.

RESULTS

On 25 implanted PC-IOLs, the incidence of cell adhesion was 100%. The cells adherent to lens included macrophages, fibroblast-like cells, epithelioid cells, giant cells, ultralarge giant cells and lymphocytes. It was seen that there was a thin proteinaceous film on the surface of the implanted PC-IOLs and the membrane was composed of fibrin collagen fibrils, macrophages, fibroblast-like cells, giant cells and fibroblasts.

CONCLUSION

The cellular response on the surface of implanted PC-IOL is a chronic foreign-body inflammatory reaction and the membrane on the surface of implanted PC-IOL is a reactive membrane of the foreign-body. However, the reaction described in this study might be applicable to human since cellular elements and membranes have been frequently reported finding in human.

Elements between the protein-coding regions of the adjacent beta 4 and alpha 3 acetylcholine receptor genes direct neuron-specific expression in the central nervous system

The expression patterns of three clustered neuronal nicotinic acetylcholine receptor (nAchR) subunit genes ordered beta 4, alpha 3, and alpha 5 overlap extensively in the peripheral nervous system (PNS) but only partially in the central nervous system (CNS). We have begun to investigate cell type-specific cis elements regulating these genes by analyzing in both cell culture and transgenic mice, a 2.8-kb fragment (-2732/+47) containing the alpha 3 promoter region, the beta 4/alpha 3 intergenic region, and a portion of the beta 4 3'-untranslated exon. The -2732/+47 fragment is preferentially active in PC12 cells relative to nonneural cell lines. Deletion analysis revealed a cell type-specific positive transcriptional element positioned in the beta 4 3'-untranslated exon. The positive element is likely to be an enhancer and not a second alpha 3 promoter, because no alpha 3 exons are present in this region. Having shown in cell culture that cell-type specific cis elements are positioned between the beta 4 and alpha 3 coding regions, we investigated the activity of -2732/+47 in vivo. Transgenic mice were generated, which carry the lacZ gene fused downstream of -2732/+47. Expression of the lacZ transgene is restricted to neurons of the CNS; no expression was detected in the PNS or in nonneural tissues. LacZ-positive cells were detected virtually exclusively in a subset of CNS nuclei that transcribe the endogenous alpha 3 gene. Some overlap was seen with the beta 4 gene, but nearly none with the alpha 5 gene. Our results demonstrate that cis elements positioned between the alpha 3 and beta 4 coding regions are important for establishing part of the restricted CNS patterns of beta 4, alpha 3, and alpha 5 gene transcription.

Comparative chromosome painting in mammals: human and the Indian muntjac (Muntiacus muntjak vaginalis)

We have used human chromosome-specific painting probes for in situ hybridization on Indian muntjac (Muntiacus muntjak vaginalis, 2n = 6, 7) metaphase chromosomes to identify the homologous chromosome regions of the entire human chromosome set. Chromosome rearrangements that have been involved in the karyotype evolution of these two species belonging to different mammalian orders were reconstructed based on hybridization patterns. Although, compared to human chromosomes, the karyotype of the Indian muntjac seems to be highly rearranged, we could identify a limited number of highly conserved homologous chromosome regions for each of the human chromosome-specific probes. We identified 48 homologous autosomal chromosome segments, which is in the range of the numbers found in other artiodactyls and carnivores recently analyzed by chromosome painting. The results demonstrate that the reshuffling of the muntjac karyotype is mostly due to fusions of huge blocks of entire chromosomes. This is in accordance with previous chromosome painting analyses between various Muntjac species and contrasts the findings for some other mammals (e.g., gibbons, mice) that show exceptional chromosome reshuffling due to multiple reciprocal translocation events.

Evolution of the black muntjac (Muntiacus crinifrons) karyotype revealed by comparative chromosome painting

The black muntjac (Muntiacus crinifrons) has an unusual karyotype of 2n = 8 in females and 2n = 9 in males. We have studied the evolution of this karyotype by hybridising chromosome-specific paints derived from flow-sorted chromosomes of the Chinese muntjac (M. reevesi, 2n = 46) to chromosomes of the black muntjac. The hybridisation pattern allowed us to infer chromosomal homologies between these two species. Tandem and centromeric fusions, reciprocal translocations, and insertions are involved in the reduction of the diploid number from 2n = 46 to 2n = 8, 9. The painting patterns further show complex chromosomal rearrangements in the male black muntjac which involve more than half the karyotype, including both sex chromosomes. Since early meiosis is reported to be normal without any visible inversion loops of the synaptonemal complex, the observed chromosomal rearrangements would lead to heterosynapsis and, therefore, leave a large fraction of the male black muntjac karyotype balanced between the two sexes.

Conservation of human vs. feline genome organization revealed by reciprocal chromosome painting

We employed fluorescence in situ hybridization (FISH) with probes established by flow sorting metaphase chromosomes of the domestic cat (Felis cattus, 2n = 38) to "paint" homologous segments on human chromosomes and, reciprocally, using human chromosome paints on feline metaphase preparations. The results revealed, by direct microscopic observation, widespread conservation of genome organization between the two mammalian orders and confirmed 90% of the homologous genes mapped to both species. Fourteen of 23 human chomosomes were hybridized with single cat probes, and 9 of 19 cat chromosomes were entirely labeled by a single human probe. All other chromosomes were labeled with only two or, at most, three probes of the respective species. Y-chromosome probes gave no signals. Approximately 30 syntenic segments were identified, and the number of translocations could be estimated to be on the order of one new translocation per 10 million years in the phylogenetic lines leading to human and cat. Using the principle of maximum parsimony, the primitive vs. derived human chromosome segments were identified by comparison to the feline, cattle, and pig genomes, a first step in reconstructing the evolutionary heritage of the mammalian radiations. The results suggest that reciprocal chromosome painting will help reconstruct the history of genomic changes by determining the polarity of chromosomal rearrangements and establishing the ancestral karyotype for each principle branching point in mammalian evolution.

Modified ligands to FA and FB in photosystem I. Proposed chemical rescue of a [4Fe-4S] cluster with an external thiolate in alanine, glycine, and serine mutants of PsaC

The FB and FA electron acceptors in Photosystem I (PS I) are [4Fe-4S] clusters ligated by cysteines provided by PsaC. In a previous study (Mehari, T., Qiao, F., Scott, M. P., Nellis, D., Zhao, J., Bryant, D., and Golbeck, J. H. (1995) J. Biol. Chem. 270, 28108-28117), we showed that when cysteines 14 and 51 were replaced with serine or alanine, the free proteins contained a S = 1/2, [4Fe-4S] cluster at the unmodified site and a mixed population of S = 1/2, [3Fe-4S] and S = 3/2, [4Fe-4S] clusters at the modified site. We show here that these mutant PsaC proteins can be rebound to P700-FX cores, resulting in fully functional PS I complexes. The low temperature EPR spectra of the C14XPsaC.PS I complexes (where X = S, A, or G) show the photoreduction of a wild-type FA cluster and a modified FB' cluster, the latter with g values of 2.115, 1.899, and 1.852 and linewidths of 110, 70, and 85 MHz. Since neither alanine nor glycine contains a suitable side group, an external thiolate provided by beta-mercaptoethanol has likely been recruited to supply the requisite ligand to the [4Fe-4S] cluster. The EPR spectrum of the C51SPsaC.PS I complex differs from that of the C51APsaC.PS I or C51GPsaC.PS I complexes by the presence of an additional set of resonances, which may be derived from the serine oxygen-ligated cluster. In all other mutant PS I complexes, a wild-type spin-coupled interaction spectrum appears when FA and FB are simultaneously reduced. Single turnover flash studies indicate approximately 50% efficient electron transfer to FA/FB in the C14SPsaC.PS I, C51SPsaC.PS I, C14GPsaC.PS I, and C51GPsaC.PS I mutants and less than 40% in the C14APsaC.PS I and C51APsaC.PS I mutants, compared with approximately 76% in the PS I core reconstructed with wild-type PsaC. These data are consistent with the measurements of the rates of cytochrome c6-NADP+ reductase activity, indicating lower rates in the alanine mutants. It is proposed that the chemical rescue of a [4Fe-4S] cluster with a recruited external thiolate at the modified site allows the mutant PsaC proteins to rebind to PS I and to function in forward electron transfer.

Human APOE protein localized in brains of transgenic mice

Transgenic mice carrying the three common human apolipoprotein E (APOE) alleles have been developed. In this study, brains of the transgenic mice have been analyzed by in situ histohybridization, immunohistochemistry, and immunoblots to determine sites of gene expression, to identify specific brain cells associated with human apoE protein, and to determine the relative concentrations of the human apoE. Results indicate that (1) human APOE mRNA and apoE protein occur in the gray and white matter of transgenic mouse brains; (2) in the hippocampus of transgenic brains, human apoE protein reacts immunologically within the same cells as the glial fibrillary acidic protein (GFAP), a specific marker for astrocytes; and (3) concentrations of the apoE isoforms determined in three heterozygous transgenic brains range from 22 to 250 pmol/g wet weight of brain.

Cloning, expression, purification and characterization of DNA topoisomerase I of Mycobacterium tuberculosis

The complete gene encoding Topoisomerase 1 (Topo I) from Mycobacterium tuberculosis (MTb), Erdman strain, has been isolated and sequenced. The coding region of this gene is 2700 nt encoding a polypeptide of 900 amino acids with a calculated molecular mass of 99353 Da. The amino-acid sequence identity compared to E. coli and Synechococcus Topo I is 22 and 30%, respectively. The gene was expressed in E. coli BL21(DE3) and purified to near homogeneity. Recombinant MTb Topo I is enzymatically active, relaxing negatively supercoiled DNA in a magnesium-dependent, ATP-independent reaction. Spermidine, a typical inhibitor of prokaryotic type I DNA topoisomerase, inhibits the activity. Unlike the more well-characterized E. coli Topo I, MTb Topo I does not contain a zinc-finger DNA-binding motif in the C-terminal domain of the protein.

Correlative memory deficits, Abeta elevation, and amyloid plaques in transgenic mice

Transgenic mice overexpressing the 695-amino acid isoform of human Alzheimer beta-amyloid (Abeta) precursor protein containing a Lys670 --> Asn, Met671 --> Leu mutation had normal learning and memory in spatial reference and alternation tasks at 3 months of age but showed impairment by 9 to 10 months of age. A fivefold increase in Abeta(1-40) and a 14-fold increase in Abeta(1-42/43) accompanied the appearance of these behavioral deficits. Numerous Abeta plaques that stained with Congo red dye were present in cortical and limbic structures of mice with elevated amounts of Abeta. The correlative appearance of behavioral, biochemical, and pathological abnormalities reminiscent of Alzheimer's disease in these transgenic mice suggests new opportunities for exploring the pathophysiology and neurobiology of this disease.

Decreased levels of CD44 protein and mRNA in prostate carcinoma. Correlation with tumor grade and ploidy

BACKGROUND

CD44, a transmembrane protein, is associated with cell-cell and cell-matrix interaction and with tumor growth and metastasis. Expression of both standard form and variant isoforms of CD44 protein has been associated with aggressive behavior and metastasis in various tumors, but has not been characterized in prostate adenocarcinoma (PAC).

METHODS

The expression of CD44 standard (CD44s) and splice variant v3, v4/5, v6, v7/8, and v10 proteins were studied in 109 PACs and correlated with tumor grade, DNA ploidy, and mRNA levels. Monoclonal antibodies against the various CD44 proteins were applied to microwave irradiated, formalin fixed, paraffin embedded sections. The DNA content of the tumors was evaluated by the Feulgen method with the CAS200 Image Analyzer. Total RNA exhibiting 18s and 28s bands was derived from two benign prostatic tissues and 5 PACs exhibiting decreased levels of CD44 protein by immunohistochemistry. The RNA was analyzed with reverse transcriptase polymerase chain reaction using CD44 specific primers.

RESULTS

The basal cells of the benign prostatic acini revealed uniform membranous staining for CD44s, v3, and v6 in 95-97% of cases. Similar staining was observed for v4/5, v7/8, and v10 in 40%, 30%, and 2% of cases, respectively. Secretory epithelial cells of the benign prostatic acini showed predominant expression of CD44s (97% of cases). Staining for CD44 variant proteins (v3, v4/5, v6, v7/8, and v10) in this location ranged from 9-22% of cases. Approximately 70% of the PACs showed significant loss of CD44s expression, which correlated with high tumor grade (Gleason > or = 7) (P = 0.01) and aneuploid status (P = 0.002). In 93-98% of the PACS, there was a complete lack of membranous expression for all CD44 variant isoforms. The metastatic PACS did not show preferential expression of either the standard form or any variant isoform. The cDNA from the normal prostates yielded a prominent CD44 standard form polymerase chain reaction product at 482 base pair (bp) and variant isoforms at approximately 650 and 850 bp. No CD44 products could be amplified from the subset of five PAC cDNAs, even when present at four-fold excess.

CONCLUSIONS

PACS exhibit down-regulation of CD44 protein expression, which correlates with high tumor grade and aneuploidy. v6 and v3 isoforms were preferentially expressed in the basal cells of benign prostatic acini. Based on a subset of cases, loss of CD44 protein expression is associated with decreased abundance of CD44 mRNA.

The molecular structure of green fluorescent protein

The crystal structure of recombinant wild-type green fluorescent protein (GFP) has been solved to a resolution of 1.9 A by multiwavelength anomalous dispersion phasing methods. The protein is in the shape of a cylinder, comprising 11 strands of beta-sheet with an alpha-helix inside and short helical segments on the ends of the cylinder. This motif, with beta-structure on the outside and alpha-helix on the inside, represents a new protein fold, which we have named the beta-can. Two protomers pack closely together to form a dimer in the crystal. The fluorophores are protected inside the cylinders, and their structures are consistent with the formation of aromatic systems made up of Tyr66 with reduction of its C alpha-C beta bond coupled with cyclization of the neighboring glycine and serine residues. The environment inside the cylinder explains the effects of many existing mutants of GFP and suggests specific side chains that could be modified to change the spectral properties of GFP. Furthermore, the identification of the dimer contacts may allow mutagenic control of the state of assembly of the protein.

[Induction of differentiation of human gastric cancer cell line SGE-7901 by retinamide]

Vitamin A and its analogus, the retinoids, are agents that are known to induce differentiation and inhibit growth on cell in vitro and in vivo. These agents show promise as prophylactic and therapeutic ones in human cancer and were noted extensively by scholars abroad, but the research has just been developed in recent years in our country. Retinamide (named briefly R II), a kind of new retinoids made in China, can induce differentiation and inhibit growth of cell, but its toxic effect is smaller than its maternal chemical compound (retinoic acid). Using automatic image analysis technology, polyacrylamide gel LDH isoenzyme electrophoresis, radioimmunoassay and condensing reaction of Con A, we have observed induction of differentiation of the R II on SGC-7901 cells. Our experiments indicate that R II can inhibit cell proliferation, decrease obviously average DNA content and nuclear area, reduce CEA secretion and condensing of the cells, and change LDH isozymoraphy of SGC-7901 cell with promoting H-type LDH and reducing M-type LDH. The change of morphology under light microscope by R II showed that the cells spread, flattened and partially lined up, and the alkalophilic quality of cytoplasm became weak. These results suggest that SGC-7901 cell under the action of R II should undergo the changes of reverse differentiation in morphological, physiological and bio-chemical aspects.

Cultured porcine myogenic cells produce insulin-like growth factor binding protein-3 (IGFBP-3) and transforming growth factor beta-1 stimulates IGFBP-3 production

Insulin-like growth factor binding proteins (IGFBP) may act locally as autocrine or paracrine regulators of insulin-like growth factor activity in specific tissues such as muscle. Although secretion of IGFBP by cultured myogenic cell lines has been examined, little is known about secretion of IGFBP by primary myogenic cell cultures. This may be because primary myogenic cultures contain non-muscle cells (fibroblasts) that complicate interpretation of IGFBP determinations. We have circumvented this problem by subculturing nonfusing cells from extensively fused porcine myogenic cultures and comparing the IGFBP production of these nonfusing, porcine muscle-derived cells with that of primary porcine myogenic cell cultures. Immunoprecipitation with specific antibodies and 125I-IGF-I ligand blot analysis showed that myogenic cultures secreted IGFBP-3 (doublet band, 43 kDa and 39 kDa), IGFBP-2 (34 kDa), IGFBP-4 (30 and 24 kDa), and IGFBP-5 (30 and 28 kDa). Muscle-derived fibroblasts secreted no detectable IGFBP-3 but approximately 10 times more IGFBP-2 than did myogenic cell cultures. Treatment of myogenic cultures for 24 h with transforming growth factor (TGF) beta-1 caused a concentration-dependent increase in IGFBP-3 secretion with a maximum 1.5-fold increase occurring at .5 ng of TGF beta-1/mL. In contrast, TGF beta-1 treatment did not stimulate detectable IGFBP-3 secretion by muscle-derived fibroblast cultures. Northern analysis of total RNA using a porcine IGFBP-3 probe revealed that TGF beta-1 treatment resulted in a fourfold increase in the steady-state level of IGFBP-3 mRNA in myogenic cultures. Insulin-like growth factor binding protein-3 mRNA was not detectable in fibroblast cultures either before or after TGF beta-1 treatment. This is the first report of IGFBP-3 secretion by cultured myogenic cells.

Developmental changes in response to heelstick in preterm infants: a prospective cohort study

Twenty-eight preterm infants of 28 weeks gestational age were observed four times over eight weeks in order to determine changes in their pain response. Both routine and sham heelstick procedures were used. Physiological (heart rate and oxygen saturations) and behavioural parameters (three upper facial actions) were used as outcomes. The responses to real heelstick were significantly greater than to sham heelstick for heart rate and all facial actions except one at 28 weeks gestational age, but not for oxygen saturation. The magnitude of response to both real and sham heelstick increased over time. Thus, the older the infant, the more robust and recognisable the response. Since even the youngest infants showed a differential response to pain, professionals caring for such infants need to be able to recognize their more subtle pain responses.

Crystal structures of CO-, deoxy- and met-myoglobins at various pH values

The distal histidine residue, His64(E7), and the proximal histidine residue, His93(F8), in myoglobin (Mb) are important for the function of the protein. For example, the increase in the association rate constant for CO binding at low pH has been suggested to be caused by the protonation of these histidine residues. In order to investigate the influence of protonation on the structure of myoglobin, we determined the crystal structures of sperm whale myoglobin to 2.0 A or better in different states of ligation (MbCO, deoxyMb and metMb) at pH values of 4, 5 and 6. The most dramatic change found at low pH is that His64 swings out of the distal pocket in the MbCO structure at pH 4, opening a direct channel from the solvent to the iron atom. This rotation seems to be facilitated by conformational changes in the CD corner. The benzyl side-chain of Phe46(CD4), which has been suggested to be a critical residue in controlling the rotation of His64, moves away from His64 at pH 4 in the deoxyMb structure, allowing more free rotation of His64. Arg45(CD3) is also important for the dynamics of myoglobin, since it influences the pK(a) of His64 and forms a hydrogen bond lattice that hinders the rotation of His64 at neutral pH. This hydrogen-bond lattice disappears at low pH. Although His64 rotates out of the distal pocket in the MbCO structure at pH 4, leaving more space for the CO ligand, the Fe-C-O angle refines to about 130 degrees, the same as those at pH 5 and 6. In the MbCO structure at pH 4, significant conformational changes appear in the EF corner. The peptide plane between Lys79(EF2) and Gly80(EF3) flips about 150 degrees. The occupancy of this conformation in the MbCO structures increases with decreases in pH. On the proximal side of the heme, the bond between the heme iron atom and N(epsilon) of His93 remains intact under the experimental conditions in the MbCO and deoxyMb structures, but appears elongated in the metMb structure at pH 4, representing either a weakened bond or the breakage of the bond in some fraction of the molecules in the crystal.

Carboxy terminal of beta-amyloid deposits in aged human, canine, and polar bear brains

Immunocytochemistry, using antibodies specific for different carboxy termini of beta-amyloid. A beta 40 and A beta 42(43), was used to compare beta-amyloid deposits in aged animal models to nondemented and demented Alzheimer's disease human cases. Aged beagle dogs exhibit diffuse plaques in the absence of neurofibrillary pathology and the aged polar bear brains contain diffuse plaques and PHF-1-positive neurofibrillary tangles. The brains of nondemented human subjects displayed abundant diffuse plaques, whereas the AD cases had both diffuse and mature (cored) neuritic plaques. Diffuse plaques were positively immunostained with an antibody against A beta 42(43) in all examined species, whereas A beta 40 immunopositive mature plaques were observed only in the human brain. Anti-A beta 40 strongly immunolabeled cerebrovascular beta-amyloid deposits in each of the species examined, although some deposits in the polar bear brain were preferentially labeled with anti-A beta 42(43). beta-amyloid deposition was evident in the outer molecular layer of the dentate gyrus in the aged dog, polar bear, and human. Within this layer, A beta 42 was present as diffuse deposits, although these deposits were morphologically distinct in each of the examined animal models. In dogs, A beta 42 was cloud-like in nature; the polar bear demonstrated a more aggregated type of deposition, and the nondemented human displayed well-defined deposits. Alzheimer's disease cases were most frequently marked by neuritic plaques in this region. Taken together, the data indicate that beta-amyloid deposition in aged mammals is similar to the earliest stages observed in human brain. In each species, A beta 42(43) is the initially deposited isoform in diffuse plaques.