[Restoration of supination of forearm by flexor carpi radialis transfer]

The dysfunction of supination of forearm following injury of brachial plexus or poliomyelitis always affects the function of hand. To find the dynamic muscle for restoration of the supination, the flexor carpi radialis was investigated on fifty male cadavers. The blood supply of the muscle was polygenic, mainly derived from the humoral and radial arteries. The movement of the muscle was innervated by median nerve. If the proximal 1/3 belly of the muscle was reserved, the blood supply and innervation of the complete muscle was reserved. According to the anatomic data, the operative procedure was designed as following: transfer the distal 2/3 of flexor carpi radialis over the ulnar aspect of the forearm to the dorsal-radial side, the tendon was fixed on the radius shaft 6 to 10 cm proximal to the styloid process with forearm in full supination. Four patients were treated and after followed up for 3.2 years average, the supination restored. It was discussed that in case of paralysis of the flexor carpi ulnaris and pronator teres, the optimal choice to restore the supination would be flexor carpi radialis.

[Genetic polymorphisms of TH01 and VWA loci in Tibetans in China]

OBJECTIVE

To understand the genetic relationship between Han population and Tibetan population, the genetic polymorphisms of two STR loci, TH01 and VWA were studied in the Tibetans in China.

METHODS

EDTA-blood specimens were collected from 89 healthy unrelated Tibetan individuals in Lasa. DNA was extracted using Chelex method. The DNA samples were amplified by PCR technique, and the PAGE horizontal electrophoresis were used to typing the PCR products.

RESULTS

There were five alleles at TH01 locus in Tibetan population. The alleles frequencies were TH01*6:0.097, TH01*7:0.227, TH01*8:0.091, TH01*9:0.481 and TH01*9.3:0.104. A total of 12 genotypes were observed in 77 individuals for TH01. For VWA locus there were seven alleles and the allele frequencies were VWA *14:0.101, VWA*15:0.034, VWA*16:0.208, VWA*17:0.303, VWA*18:0.208, VWA*19:0.129 and VWA*20:0.017. A total of 20 genotypes for VWA were observed in 89 individuals. The results of test for Hardy-Weinberg equilibrium showed that the genotype distributions observed at both STR loci were correspondent with those expected(chi-square =7.421 df =8 P>0.05 for TH01; chi-square =19.61 df =14 P>0.05 for VWA).

CONCLUSION

There is no significant difference between Han and Tibetan populations in allele frequencies at TH01 and VWA loci. The results of analysis using genetic distance and phylogenetic tree indicate that Tibetan population is identical with Han population at TH01 and VWA loci .

Transzygomatic coronoidectomy through an extended coronal incision for treatment of trismus due to an osteochondroma of the coronoid process of the mandible

Osteochondroma is the most common benign tumor of the skeletal system. In the craniofacial skeleton, however, osteochondroma is uncommon. Even more rare is osteochondroma of the coronoid process. A review of the literature reveals only 31 reported cases of osteochondroma of the coronoid process of the mandible. The preponderance of patients were young men (67.7%) and most presented with a facial deformity. As a benign tumor, the problems with surgical treatment have dealt with the inaccessibility of the lesion and hence the surgical approach of choice. The previous surgical approaches have either been intraoral, external, or a combination of both. We present a transzygomatic approach via a coronal incision that gives excellent access and a good cosmetic result, and protects the facial nerve from damage.

U-74389G suppresses lipid peroxidation and apoptosis following focal cerebral ischemia and reperfusion in rats

OBJECTIVE

To study the antioxidant and antiapoptotic effects of U-74389G on ischemic brain in rats.

METHODS

Right focal cerebral ischemia and reperfusion was induced by suturing in 103 male SD rats weighing 280-310 g. To determine LPO in the cortex and striatum, we randomly divided 78 rats into 5 groups: group 1, sham-operative group (6 rats); group 2, control (18); group 3, U-74389G administration before ischemia (18); group 4, U-74389G administration before reperfusion; group 5, CS-4 vehicle as negative control. Groups 2-5 were further divided into 3 subgroups according to the duration of reperfusion. Another 25 rats were similarly grouped (5) to detect apoptosis with TUNEL stain.

RESULTS

The concentrations of MDA in groups 3 and 4 were reduced and the activities of SOD and concentrations of GSH were partially restored as compared with the control group. These effects were more significant in group 3 than in group 4. Otherwise, CS-4 can not provide protective effects. The number of apoptotic cells in groups 3 (P < 0.01) and 4 (P < 0.05) was significantly reduced as compared with the control group.

CONCLUSIONS

U-74389G has antioxidant and antiapoptotic effects on ischemic brain in rats. The administration of U-74389G before the onset of ischemia was more useful than that before the onset of reperfusion.

Enhancer control of V(D)J recombination at the TCRbeta locus: differential effects on DNA cleavage and joining

Deletion of the TCRbeta transcriptional enhancer (Ebeta) results in nearly complete inhibition of V(D)J recombination at the TCRbeta locus and a block in alpha beta T cell development. This result, along with previous work from many laboratories, has led to the hypothesis that transcriptional enhancers affect V(D)J recombination by regulating the accessibility of the locus to the recombinase. Here we test this hypothesis by performing a detailed analysis of the recombination defect in Ebeta-deleted (Ebeta-/-) mice using assays that detect various reaction intermediates and products. We found double-strand DNA breaks at recombination signal sequences flanking Dbeta and Jbeta gene segments in Ebeta-/- thymuses at about one-third to one-thirtieth the level found in thymuses with an unaltered TCRbeta locus. These sites are also subject to in vitro cleavage by the V(D)J recombinase in both Ebeta-/- and Ebeta+/+ thymocyte nuclei. However, the corresponding Dbeta-to-Jbeta coding joints are further reduced (by 100- to 300-fold) in Ebeta-/- thymuses. Formation of extrachromosomal Dbeta-to-Jbeta signal joints appears to be intermediately affected and nonstandard Dbeta-to-Dbeta joining occurs at the Ebeta-deleted alleles. These data indicate that, unexpectedly, loss of accessibility alone cannot explain the loss of TCRbeta recombination in the absence of the Ebeta element and suggest an additional function for Ebeta in the process of DNA repair at specific TCRbeta sites during the late phase of the recombination reaction.

Syntagms in development and evolution

The genetic analysis of segmentation, neurogenesis, appendage formation and other developmental processes has revealed that the development of Drosophila can be broken down into discrete elementary operations. Thus development can be viewed as a stepwise process where each step is driven by a small group of genes working interactively. García-Bellido proposed that each of these groups be called a "syntagm". In this review, we will describe a series of developmental syntagms, and explore the consequences of this discontinuous organization of the developmental program on evolution.

[Study on HCV infection and the distribution of HCV genotypes in different populations in Shenyang area]

3,902 serum samples in different populations were tested for anti-HCV by ELISA. Among 100 samples of them, genotypes of HCV were detected by PCR with type-specific primers. The results showed: a) anti-HCV positive rates in general populations were 0.42%-1.66%; b) anti-HCV positive rates in the group of post-transfusion hepatitis and sporadic hepatitis (excluding HAV, HBV, EBV, CMV infection), hepatitis B post hepatitis cirrhosis (excluding HBV infection) and primary hepatocarcinoma were significantly higher than the group of patients without liver diseases or the group of patients without transfusion (P < 0.01); c) in HCV genotyping, HCV-II, HCV-III, II/III mixed type were 58%, 27%, 14% respectively. The rate of infection with HCV-III, was 80% in normal population but 91.7% with type II HCV in the group of patients with cirrhosis. These results suggested: (1) patients with different liver diseases were under high risk of HCV infection; (2) type HCV-II was predominant followed by HCV-III as well as II/III mixed in HCV genotype distribution of Shenyang area. Different genotypes of HCV might be related to the severity of hepatitis C.

Analysis of the 5' flanking sequence of the human norepinephrine transporter gene

The human norepinephrine transporter (NET) gene was cloned and structurally analyzed. The far 5' fragment containing exon 1 (a non-coding exon) and exon 2 was sequenced. The transcription start site of the gene in human brain stem tissue was determined by primer extension analysis. It was found that the gene could be transcribed from multiple starting points. The 5' flanking sequence contains a proximal G-C rich region, one possible GSG element and several SP1 sites. However it does not contain TATA box and CAAT box motifs. Gel shift analysis with nuclear extracts from different tissues of mouse shows that the G-C rich region may be involved in tissue specific expression of the gene.

[The association of HLA-B27 binding peptide and spondylarthropathies]

OBJECTIVE

To explore the association of spondylarthropathies HAL-B27 binding peptide.

METHODS

B27 molecules expressed on the B27-T2 mutant cell line do not have peptides. Such empty B27 molecules were not recognized by peptide-dependent monoclonal antibody, B27.M2. Positive B27.M2 reactivity resulted when B27-T2 cells were incubated with peptide RRKAMFEDI derived from Chlamydia hsp60. THe importance of each residue in RRKAMFEDI was analysed by testing analogs in which each of the 9 residues in the peptide was consecutively substituted by 19 other amino acids.

RESULTS

B27.M2 reactivity was the highest with arginine in second residue. The reactivities of residues other than arginine were less than 30% of the value with the parent peptide.

CONCLUSION

The stringency for other residues was relatively low, indicating that immune recognition of B27-peptide complexes might have rather low stringency for peptide sequences. These peptide residues probably influenced antibody reactivity by inducing conformational changes.

A drug-lipid interaction model: atropine induces interdigitated bilayer structure

X-ray diffraction and fluorescence methods have been carried out to examine the effects of a drug, atropine, on the structure of model membranes: dipalmitoylphosphatidylglycerol(DPPG) multilamella vesicles(MLVs). A structural analysis by small angle x-ray diffraction shows that, with incorporation of atropine, the lamella repeating period of DPPG MLV is decreased from 5.89 nm to 4.52 nm. Using fluorescence probe 1,6-diphenyl-1,3,5-hexatriene(DPH) we find that the fluorescence intensity of DPH reduces largely at a narrow scope of atropine concentration. The experiments of fluorescence polarization of n-(9-anthroyloxyl)-stearic acid (nAS) and 16-(9-anthroyloxyl)-palmiticacid (16AP) discover that the normal polarization gradient almost disappears in DPPG/atropine system. By colligating the above results, we can draw a conclusion that atropine induces the transition from non-interdigitated to interdigitated stricture of DPPG vesicles in gel phase, which provides a sound model of drug-lipid interaction.

Effect of mild hypothermia on the changes of cerebral blood flow, brain blood barrier and neuronal injuries following reperfusion of focal cerebral ischemia in rats

OBJECTIVE

To compare the effects of mild hypothermia induced in different time courses on rats subjected to 3 hours (h) of ischemia followed by 3 h or 72 h of reperfusion.

METHODS

Eighty male Sprague-Dawley rats were divided into three mild hypothermic (MHT, 32 +/- 0.2 degrees C) groups, including intra-ischemia (MHTi), intra-reperfusion (MHTr), and intra-ischemia/reperfusion (MHTi + r) group, and one normothermic group (NT, 37 +/- 0.2 degrees C) as the control. Reversible focal ischemia was carried out in rats with suture model. The cortical blood flow was measured during 3 h of ischemia followed by 3 h of reperfusion. The permeability of brain blood barrier (BBB) was estimated after 3 h of reperfusion. The infarct volume was measured at 72 h after reperfusion to determine the effects of MHT.

RESULTS

The acute post-ischemic hyperperfusion and delayed hypoperfusion in ischemic perifocal region and sustained hypoperfusion in ischemic core were inhibited in MHTi + r and MHTi rats (P < 0.05). MHTi + r protection on post-ischemic progressive hypoperfusion in the perifocal region was more effective than that of MHTi (P < 0.05). The BBB disruption and the infarct volume were significantly reduced in both MHTi and MHTi + r groups (P < 0.05), especially in the MHTi + r rats.

CONCLUSIONS

This study demonstrates that MHTi + r has more substantial protective effects on reducing ischemia/reperfusion injury than MHTi. It may inhibit post-ischemic hyperperfusion and delayed or sustained hypoperfusion in ischemic perifocal regions, and reduce brain blood barrier disruption in the cortex region.

Immunity in chimpanzees chronically infected with hepatitis C virus: role of minor quasispecies in reinfection

We have previously reported that chimpanzees chronically infected with hepatitis C virus (HCV) could be reinfected, even with the original infecting strain. In this study we tested the hypothesis that this might reflect the presence of minor quasispecies to which there was little or no immunity. To evaluate this hypothesis, we sequenced multiple clones taken at intervals after primary infection and rechallenge from four chronically infected chimpanzees. The inoculum used in these studies (HCV-H, genotype 1a) revealed 17 separate variants among 46 clones sequenced. Following challenge, each of the four challenged animals showed marked alterations of their quasispecies distribution. The new variants, which appeared 1 to 6 weeks after challenge, were either identical to or closely resembled variants present in the challenge inoculum. These results, paralleled by an increase in viremia in some of the challenged animals, suggest that quasispecies in the challenge inoculum were responsible for signs of reinfection and that there was little immunity. However, the newly emerged quasispecies completely took over infection in only one animal. In the remaining three chimpanzees the prechallenge quasispecies were able to persist. The natural evolution of infection within chimpanzees resulted in variants able to compete with the inoculum variants. Whether through reexposure or the natural progression of infection, newly emerged quasispecies are likely to play a role in the pathogenesis of chronic HCV infection.

[Free jejunal grafts for reconstruction of pharynx and cervical esophasgus]

Eleven patients with hypopharyngeal carcinoma were treated surgically and the pharynx and cervical esophagus were reconstructed with free jejunal grafts through the technique of microvascular anastomosis. The microvascular anastomosis were all successful and the patients all survived the operations. The operations were performed at one time with only a few complications. There were 2 cases of pharyngeal fistula and 1 case of bleeding from the anastomotic site. The patients could eat by their mouths and swallow very well just 15 days after the operation. The 3-year suvival rate was 36%. The main causes of death were the recurrence and the metastasis to the cervical lymph nodes. We came to the conclusion that the operation is safe with high success rate and no mortality during operation, and it is less injurious than the gastropharyngeal anastomosis. The key point of the operation is the surgeon's mastery of the microvascular anastomosis technique.

[Genetic polymorphisms of FABP2 and F13A1 loci in Han population]

OBJECTIVE

To find more STR loci usable in forensic medicine and understand the distribution of the genetic polymorphisms of two STR loci FABP2 and F13A1 in the Han population in Chengdu.

METHODS

EDTA-blood specimens were collected from 115 healthy unrelated Han individuals in Chengdu, DNA was extracted using Chelex method. The DNA samples were amplified by PCR technique, and the PAGE horizontal electrophoresis was used for typing of the PCR products.

RESULTS

The allele frequencies were FABP2*1:0.513,FABP2*2:0.096, FABP2*3:0.330, FABP2*4:0.052, FABP2*5:0.009, and 10 genotypes were observed in 115 individuals for FABP2; while for F13A1, the allele frequencies were F13A1*1:0.128, F13A1*2: 0.053, F13A1*3:0.288, F13A1*4:0.527, F13A1*5:0.004 and 10 genotypes were observed in 113 individuals. The result of test for Hardy-Weinberg equilibrium showed that the genotype distribution observed at FABP2 locus was correspondent with the expected.

CONCLUSION

FABP2 may be a useful marker for paternity test or personal indentification of biological stain. On the other hand, more studies need to be done to understand the polymorphism at F13A1 locus in Chinese population because a deviation from Hardy-Weinberg equilibrium has been observed in this Han population.

[Endoscopic variceal ligation combined with partial splenic embolization: preliminary clinical results]

Endoscopic variceal ligation combined with partial splenic embolization (EVL-PSE) was performed in a group of 13 patients with esophageal variceal bleeding and hypersplenism due to portal hypertension from January 1997 to March 1998. PSE was performed one to two weeks before or one week after initial EVL, and a range of 30% to 60% of the splenic parenchyma was embolized. Repeated EVL was performed at two week intervals until the varices were eradicated. Active bleeding in the nine patients was successfully controlled and all the varices of the 13 patients were eradicated after EVL-PSE. Eradication of the varices required two to five(mean 3.1) EVL sessions, follow-up ranging from 2 to 16 months(mean 6.9 months). In all but one case, no rebleeding occurred. All patients after PSE showed a good response on peripheral blood cell count and reduction of splenomegaly. No major complication or death related to the combination therapy was observed. Preliminary results in this study show that this combination therapy may result in more rapid eradication of the varices and reduce rebleeding after endoscopic variceal ligation. However, more data and studies may be necessary for further evaluation.

[Primary study of bacterial adhesion of prosthetic valve materials]

The adhesion of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans to Dacron and pyrolite carbon was measured in vitro with plate counting. The experimental result showed: the bacterials used in the experiment have adhesion to prosthetic valve materials; the bacterials have stronger adhesion to Dacron than to Pyrolite carbon; the bacterial adhesive capacity is significantly different and is affected by mechanical and chemical nature of biomaterials; Staphylococcur aureus has the strongest adhesion to Dacron, and Pseudomonas aeruginosa has the strongest adhesion to pyrolite carbon in all bacterials.

[Studies on the analgesic and antiinflammatory action of radix Linderae extract]

Both of aqueous extract and alconol extract of Radix Linderae at a dose 5 g/kg and 10 g/kg could length obviously pain threshold in mice in hot plate test. The samples at a dose 20 g/kg could inhibit significantly the writhing frequency induced by potassium antimony tartate in mice, also antagonize the swelling of ear induced by inflammatory agent and decrease the swelling rate. The component further isolated from the plant could antagonize the swelling of rat toes induced by carrageenin.

A calcium-metalloribozyme with autodecapping and pyrophosphatase activities

A previously-isolated ribozyme with capping activity has self-decapping activity, here characterized alongside its additional, somewhat parallel, pyrophosphatase reaction. Decapping is 10-50 times slower than the pyrophosphatase activity, depending on pH. The RNA accelerates pyrophosphate release 170 000 times over a control composed of randomized pppRNA, and 5' capped RNA accelerates decapping 1000-fold over random capped RNA. Triphosphate-linked G(5')pppRNA also supports an unusual cap-exchange reaction, exchanging its cap with guanosine 5'-tetraphosphate to form pentaphosphate-linked G(5')pppppRNA. GDP, a capping reactant for the RNA, appears to suppress both decapping and pyrophosphatase activities. Autodecapping and pyrophosphatase activities have in common an unusual divalent metal ion requirement for Ca2+ or less effectively Mn2+, and both are active over a broad pH range of 4.5-9. 0. These characteristics resemble the capping activity of the same RNA. Kinetic analysis reveals a well-defined Ca2+-RNA complex, and Mg2+ and Sr2+ act as competitive inhibitors of Ca2+. A strong Ca2+-binding site is suggested by a low KM of 40-60 microM at pH >/= 7.0. The role of Ca2+ in these reactions can be surmized from literature data on reactivity of nucleotide phosphates. Pyrophosphatase, capping, and decapping activities of isolate 6 RNA are apparently carried out by a single reaction center, whose rate of reaction with all nucleophiles sums to a constant total rate. This suggests a universal rate-limiting step. Versatile activation of alpha-phosphate by this reaction center raises the possibility of combinatorial ribozymes.

[Repair of long segment bone defect of femur by free juxtaposed bilateral fibulae autograft]

There were several methods, such as free single and folded fibulae autograft, composed tissue autograft, however, it is still very difficult to repair long segment bone defect. In December 1995, we used free juxtaposed bilateral fibulae autograft to repair an 8 cm of femoral bone defect in a 4 years old child in success. The key procedure is to strip a portion of the neighboring periosteal sleeve of juxtaposed fibulae to make bare of the opposite sides of the bone shafts, suture the opposite periosteal sleeves, keep the nutrient arteries, and reconstruct the blood circulation of both fibular by anastomosis of the distal ends of one fibular artery and vein to the proximal ends of the other fibular artery and vein, and anastomosis of the proximal ends of the fibular artery and vein to lateral circumflex artery and vein. After 22 months follow up, the two shafts of juxtaposed fibulae fused into one new bone shaft. The diameter of the new bone shaft was nearly the same as the diameter of the femur. There was only one medullary cavity, and it connected to the medullary cavity of femur. This method also cold be used to repair other long segment bone defect.

Interaction of the delta-endotoxin CytA from Bacillus thuringiensis var. israelensis with lipid membranes

We investigated the binding of CytA, a cytolytic delta-endotoxin from Bacillus thuringiensis var. israelensis, to small unilamellar lipid vesicles (SUV) and the accompanying changes in the overall CytA conformation. From the titration of tryptophan fluorescence with SUV, we determined the apparent association constants of 3500 M-1 and 11000 M-1 for the protoxin CytA27 and the proteolytically activated toxin CytA24, respectively. Inclusion of a negatively charged lipid or a positively charged lipid analog in the membrane did not affect the binding parameters, which suggests that membrane binding is not driven by electrostatic interactions. A decrease in the intensity of the CytA tryptophan fluorescence upon interaction with lipids and the absence of a blue shift in remaining fluorescence indicate that the tryptophan-containing regions of the protein do not significantly penetrate into the hydrophobic core of the lipid bilayer. This finding was corroborated by the lack of additional quenching by brominated or spin-labeled lipids, irrespective of the location of the quenching moiety in the depth of the bilayer. However, the interaction with lipids decreases quenching with the soluble quenchers acrylamide and KI, and the remaining fluorescence is blue-shifted. The observed decrease in fluorescence anisotropy upon membrane binding is not consistent with simple immobilization of CytA on the surface of SUV. We showed by FTIR spectroscopy and differential scanning calorimetry (DSC) that binding to the membrane causes a significant loosening of the protein structure. This is consistent with the fluorescence quenching and anisotropy data. Our experiments provide evidence against CytA's substantially penetrating the lipid bilayer and creating well-defined proteinaceous channels.

[Implantation of allogenic osteoblast combined with calcium phosphate composites]

The aim of this experiment was to study the osteogenesis in vivo of allogenic osteoblast combined culture with calcium phosphate composites. The osteoblasts were obtained by enzymatic digestion of periosteum from fibula subcultured to 13 generations, the cells were combined culture with hydroxyapatite and biphasic calcium phosphate. Subseguently, the composite was implanted into rabbits subcutaneously or intramuscularly. The blank material was implanted in the contralateral side as control. Four weeks later, all animals were sacrificed. All the implants were examined by gross observation, histological examination and EDXA. The results showed: 1. obvious ingrowth of connective tissue with very little inflammatory reaction; 2. new bone formation in the composites with deposit of Ca and P on the surface of osteoblast, but none in the blank materials; 3. no significant difference of new bone formation between the different sites of implantation or different materials, but those implanted intramuscularly had lamellae form of new bone while those implanted subcutaneously had only mineralization of extracellular matrix. The conclusion were: 1. the composites are biocompatible with prior osteogenesis property; 2. periosteal-derived allogenic osteoblasts obatined by enzymatic digestion could survive following implantation with bioactivity; 3. rich blood supply might be advantageous to new bone formation and its maturation.

Versatile 5' phosphoryl coupling of small and large molecules to an RNA

A Ca2+-requiring catalytic RNA is shown to create 5' phosphate-phosphate linkages with all nucleotides and coenzymes including CoA, nicotinamide adenine dinucleotide phosphate, thiamine phosphate, thiamine pyrophosphate, and flavin mononucleotide. In addition to these small molecules, macromolecules such as RNAs with 5'-diphosphates, and nonnucleotide molecules like Nepsilon-phosphate arginine and 6-phosphate gluconic acid also react. That is, the self-capping RNA isolate 6 is an apparently universal 5' phosphate-linker, reacting with any nucleophile containing an unblocked phosphate. These RNA reactions demonstrate a unique RNA catalytic capability and imply versatile and specific posttranscriptional RNA modification by RNA catalysis.

5'-RNA self-capping from guanosine diphosphate

A selected RNA (isolate 6) efficiently catalyzes a self-capping reaction with free GDP, yielding the same 5'-capped structure as is formed by protein GTP:RNA guanylyltransferase. This unexplored RNA-catalyzed reaction type involving nucleophilic attack on phosphate by phosphate adds to the variety of possible postsynthetic RNA-catalyzed RNA modifications. The selected RNA requires only Ca2+ for activation and has a broad active pH range of 4.5-9.0. The RNA also has a 5'-pyrophosphatase activity.

Characterization of 5'-proximal sequence of mouse GABA transporter gene (GAT-1)

The cDNA molecule encoding the mouse GABA transporter gene (GAT-1) was used as probe for selecting GAT-1 gene from mouse genomic library. A positive clone, harboring the whole open reading frame of the GAT-1 protein and designated as MGABAT-G, was fished out from the library, the 5' proximal region and intron 1 were sequenced and analysed, and low homology was found in the above region between GAT-1 genes from mouse and human except some short conserved sequences. The DNA-protein interactions between DNA fragments containing the conserved sequences in the 5' proximal region and nuclear proteins from different tissues of mouse were studied by means of gel-shift assay, and Southern-Western blot. The results indicate a possible positive-negative regulation mode controlling the expression of the mouse GAT-1 gene.

Conformational studies of dithymidine boranomonophosphate diastereoisomers

The boranophosphate ester nucleotides are a new class of nucleic acid analogues that are isoelectronic and isostructural to normal phosphodiester nucleic acids and that maintain the anionic charge of the nucleic acid backbone. The two P-diastereoisomers of dithymidine boranomonophosphates were separated using reverse phase HPLC; the faster and slower eluting isomers are designated as d(TpBT)-1 and d(TpBT)-2, respectively. Conformations of the isomers were studied using-circular dichroism (CD) and NMR, and compared to the analogous phosphate diester, d(TpT). This comparison allowed the effects of the borane group and chirality of the boranophosphate linkage on sugar and base conformations to be assessed. The CD spectra of the diastereoisomers are consistent with both having a B-type conformation. Analysis of the 1H-1H and 1H-31P coupling constants showed that these conformations are similar to those of the unmodified parent dimer; specifically, the 2'-deoxyribose rings prefer the S (C2'-endo) conformation, and the C4'-C5' and C5'-O5' rotamers are primarily in the gamma + and beta + conformations, respectively. Conformational differences between the diastereoisomers and between the modified and unmodified dimers are manifested by differences in the preferences of the 3'-residues to adopt S sugar pucker and beta + conformations. There is reduced preference for the S sugar pucker of the 3'-residue in d(TpBT)-1 relative to d(TpBT)-2, which is similar to d(TpT). There is less preference for the beta + conformation of the 3'-residue in d(TpBT)-2 relative to d(TpBT)-1 and d(TpT). Based on the CD results, the temperature dependences of the thymidine H6 chemical shifts, and the derived sugar ring and backbone conformational parameters, we conclude that the borane group exerts a minimal influence on the sugar conformations and base stacking interactions. Preliminary assignment of the absolute configuration of the pair of SP and RP diastereoisomers to d(TpBT)-1 and d(TpBT)-2, respectively, is made on the basis of enzyme selectivity and NOE difference experiments.

Induction of alternative splicing of HLA-B27 by bacterial invasion

OBJECTIVE

Alternative splicing of certain class I major histocompatibility complex pre-messenger RNA (pre-mRNA) is known to lead to generation of a cell-free soluble protein analog. This study was undertaken to examine whether this process occurs with HLA-B27, whether the process is modified by arthritis-causing bacteria, and whether the assembly of the soluble molecules follows the same pathway as the integral parent molecules.

METHODS

Alternative splicing of pre-mRNA was analyzed by reverse transcriptase-polymerase chain reaction, and assembly of soluble HLA-B27 by immunoprecipitation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography.

RESULTS

There was alternative splicing of the pre-mRNA of HLA-B27. The process could be amplified by invasion with Salmonella or Yersinia bacteria. The soluble HLA-B27 was assembled in a pathway similar to that of the parent molecule.

CONCLUSION

The association between arthritis-causing bacteria and HLA-B27 positive cells is a complex event. Soluble HLA-B27 is a potential key player.

Gene structure of the rat kainate receptor subunit KA2 and characterization of an intronic negative regulatory region

We have isolated and analyzed the structure of the gene grik5 (glutamate receptor ionotropic kainate 5), encoding the rat kainate receptor subunit KA2. Six overlapping DNA fragments containing the entire grik5 gene were identified in a rat genomic library. grik5 is a unique gene composed of 20 exons that together span over 54 kilobases (kb). Reporter gene analysis demonstrated that 2 kb of grik5 5'-flanking sequence confers tissue-specific expression on a chloramphenicol acetyltransferase gene in vitro. We show that (i) the first intron of grik5 (3.4 kb) inhibited transcription of the chloramphenicol acetyltransferase gene driven by the 2-kb grik5 5'-flanking region; (ii) the negative regulatory element was located within 500 bp of the 3'-end of intron 1, and this 500-bp fragment selectively bound nuclear proteins isolated from neural and nonneural cells; (iii) the effect of the negative regulatory element on grik5 transcription was orientation- and distance-independent; and (iv) a 24-nucleotide sequence (CTTTCTGTGGCCTCTGACCTTTCC) was identified as the binding site for nuclear proteins within the 500-bp fragment, as determined by footprinting and gel shift assays. We conclude that an intronic element that displays features of a silencer modulates grik5 transcription.

Inhibition of Toosendanin on the delayed rectifier potassium current in neuroblastoma x glioma NG108-15 cells

The effect of Toosendanin (TSN), a presynaptic transmission blocker, on the outward delayed rectifier potassium current (IKD) of NG108-15 cells was studied by using the whole-cell voltage-clamp technique. It was observed that externally applying TSN not only reduced IKD amplitude in a dose-dependent and partial reversible manner but also accelerated its inactivation. The effect of internally applying TSN was also examined by including TSN in the electrode, and it was the same as that of externally applying TSN. Further, comparison observations with TEA, 4-AP, verapamil, nifedipine, and (+/-)-Bay K 8644 were also made, and the results were as follows. The time courses of TSN's inhibition effect as well as its recovery after washing were much slower than those of TEA and 4-AP. Externally applying TEA or 4-AP reduced IKD amplitude but did not accelerate its inactivation. Externally applying verapamil, nifedipine, or (+/-)-Bay K 8644, however, similarly to the effect of TSN, not only reduced IKD amplitude but also accelerated its inactivation. Thus, from the obtained results it is suggested that TSN might diffuse into the cell interior and act intracellularly, and the underlying mechanism might be different from that of TEA and 4-AP but similar to that of verapamil, nifedipine, and (+/-)-Bay K 8644 to some extent.

Membrane permeabilization induced by cytolytic delta-endotoxin CytA from Bacillus thuringiensis var. israelensis

CytA is a member of a functionally defined family of insecticidal delta-endotoxins occurring in parasporal crystals of Bacillus thuringiensis var. israelensis. We investigated the ability of CytA to permeabilize the membrane and release fluorescence marker molecules from unilamellar lipid vesicles. Both protoxin (27 kDa) and proteolytically activated toxin (24 kDa) were very effective in permeabilization of unilamellar lipid vesicles: concentrations as low as several nanomolar produced a significant effect. The toxin was about 2-3 times more effective than the protoxin. The concentration of CytA required for the same extent of calcein release in large unilamellar vesicles (LUV) was 5-10 times lower than that in small unilamellar vesicles (SUV). Both small (calcein) and large (fluorescein-dextrans, MW 3000 and 10 000) molecules were released from the vesicles by CytA with comparable single-exponential kinetics. The release was an all-or-none event, i.e., each vesicle either released all of its contents or remained completely intact. Binding of CytA to lipid membranes did not show appreciable cooperativity, the apparent binding constant (Kapp) being on the order of 10(5) M-1. The plots of kinetics of release vs bound protein/ lipid ratio and the differential effects of CytA on LUV vs SUV indicate that at least 140 toxin molecules or 311 protoxin molecules must bind to an LUV before the latter starts losing its integrity. The necessity of adsorption of this relatively large number of toxin molecules to trigger permeabilization, together with the lack of discrimination in the size of the released marker molecules, suggests that the effect of CytA is a general, detergent-like, perturbation of the membrane rather than creation of small, well-defined, proteinaceous channels.

Searching eye movement, smooth pursuit eye movement and schizophrenia

OBJECTIVE

To detect whether the smooth pursuit eye movement (SPEM) and searching eye movement (SEM) could be considered as a biological marker of schizophrenia, and used as a tool in helping diagnosis of schizophrenia.

METHODS

88 schizophrenics, 77 patients with mood disorders, 32 with "neurosis", and 74 normal healthy controls were examined for SPEM and SEM individually. The authors verified the results in all the first-visit 150 outpatients in March 1993 by comparing the examination results with the clinical diagnoses after a 6-month follow-up.

RESULTS

Significant differences were found in the number of eye fixation (NEF) and total eye scanning length (TESL) of SEM between schizophrenics and normal controls or patients with other disorders. Less NEF and shorter TESL could be helpful in differential diagnosis, and the agreement rate, Kappa coefficient was 0.62. No significant differences were found in SPEM in this investigation between non-medicated schizophrenics and normal controls.

CONCLUSION

Searching eye movement (SEM) might be considered as a biological marker of schizophrenia and might be used as a supplementary tool in its diagnosis.

Assessment of chromatographic peak purity by means of artificial neural networks

An improved chemometric approach is proposed for assessing chromatographic peak purity by means of artificial neural networks. A non-linear transformation function with a back-propagation algorithm was used to describe and predict the chromatographic data. The Mann-Whitney U-test was used for the concluding the purity of the chromatographic peak. Simulation data and practical analytical data for both pure and mixture samples were analysed with satisfactory results. A prior knowledge of the impurity and the related compound is unnecessary when a slight difference between their chromatogram and spectrum exists. The performance on simulated data sets by this approach was compared with the results from principal component analysis.

Interaction of nitric oxide synthase with the postsynaptic density protein PSD-95 and alpha1-syntrophin mediated by PDZ domains

Neuronal nitric oxide synthase (nNOS) is concentrated at synaptic junctions in brain and motor endplates in skeletal muscle. Here, we show that the N-terminus of nNOS, which contains a PDZ protein motif, interacts with similar motifs in postsynaptic density-95 protein (PSD-95) and a related novel protein, PSD-93.nNOS and PSD-95 are coexpressed in numerous neuronal populations, and a PSD-95/nNOS complex occurs in cerebellum. PDZ domain interactions also mediate binding of nNOS to skeletal muscle syntrophin, a dystrophin-associated protein. nNOS isoforms lacking a PDZ domain, identified in nNOSdelta/delta mutant mice, do not associate with PSD-95 in brain or with skeletal muscle sarcolemma. Interaction of PDZ-containing domains therefore mediates synaptic association of nNOS and may play a more general role in formation of macromolecular signaling complexes.

A patient-derived cytotoxic T-lymphocyte clone and two peptide-dependent monoclonal antibodies recognize HLA-B27-peptide complexes with low stringency for peptide sequences

HLA-B27 molecules expressed on the T2 mutant cell line do not have peptides. Such empty HLA-B27 molecules were not recognized by an HLA-B27-restricted cytotoxic T-lymphocyte (CTL) clone (auto-1) derived from synovial fluid. To test for peptide dependency of the clone, B27-T2 cells were incubated with a panel of 48 different peptides. This lack of stringency was compared with that of a peptide-dependent monoclonal antibody, B27.M2. Positive B27.M2 reactivity resulted when the B27-T2 cells were incubated with two peptides: RRKAMFEDI and RRMGPPVGHR, derived from Chlamydia HSP60 and human ribonucleoprotein, respectively. Because of the limited availability of CTL versus monoclonal antibody, the specificity of B27.M2 was studied in greater detail. The importance of the HLA-B27 heavy chain in antibody recognition of class I-peptide complexes was demonstrated by site-directed mutagenesis. The stringency of the peptide residues was tested by making analogs of each of the nine residues in RRKAMFEDI, creating a panel of 180 analogs. Although stringency was highest for the sixth position, as many as six different amino acids provided positive reactivity. These results indicate that immune recognition of HLA-B27-peptide complexes might have rather low stringency for the peptide sequences. In theory, then, pathogen-derived peptides which induce autoimmunity by generating autoreactive CTL might not share much sequence similarity with the responsible self peptides.

Transforming growth factor beta 1 (TGF beta 1) is an autocrine positive regulator of colon carcinoma U9 cells in vivo as shown by transfection of a TGF beta 1 antisense expression plasmid

A transforming growth factor beta1 (TGF beta1) antisense expression plasmid under constitutive control of the Rous sarcoma virus promoter was introduced into the highly tumorigenic and invasive colon carcinoma U9A cell line, which uses its autocrine TGF beta1 as a growth-stimulating factor. Stable transfectants were infrequent, and only the K6 transfectant exhibited 39 and 33%, respectively, of the levels of TGF beta1 mRNA and active, secreted TGF beta1 protein of the parental line. K6 exhibited no change in TGF beta2 expression, and TGF beta3 expression was not detected in either parental or transfectant cells. Compared to the parental line, the K6 antisense transfectant exhibited a 3-fold increase in lag time in anchorage-dependent colony formation. The parental line was 44 times as invasive through a collagen l-coated polycarbonate membrane in vitro as K6 cells and, after s.c. injection at low-cell inocula, U9A cells induced tumors 75 times as large in vivo as did the K6 antisense transfectant. The decreases in in vitro invasion and anchorage-dependent colony formation seen in K6 cells were largely reversed by the addition of TGF beta1. Tumors that did arise from the K6 antisense transfectant cells had lost antisense TGF beta1 expression and expressed the same TGF beta1 mRNA levels as controls. U9A cells were more metastatic to the liver after intrasplenic injection than K6 cells. These findings demonstrate a role for autocrine TGE beta1 in colon cancer tumorigenicity and invasion. They also show that a relatively small decrease in TGF beta1 levels was enough to markedly decrease colon carcinoma cell aggressiveness. This is not unprecedented, as we had found in an earlier study that a small, 2-4-fold increase in TGF beta1 protein levels in human colon cancers correlated with disease progression to metastases (E. Friedman et al., Cancer Epidemiol, Biomarkers & Prev., 4:549-554, 1995).

Boron-containing oligodeoxyribonucleotide 14mer duplexes: enzymatic synthesis and melting studies

A set of three 14mer oligodeoxyribonucleotides of sequence d(5'-CTATGGCCTCAG*CT-3'/3'-GATACCGGAGTCGA-5') containing G* variants either as 2'-deoxyguanosine phosphate (unmodified), N7-cyanoborane 2'-deoxyguanosine phosphate (base-modified) or 2'-deoxyguanosine boranophosphate (backbone-modified) were synthesized by template-directed primer extension. Both the N7-cyanoborane 2'-deoxyguanosine triphosphate and 2'-deoxyguanosine alpha-boranotriphosphate nucleotides are good substrates for Sequenase. We infer that a single Sp boranophosphate linkage (which has a stereochemistry equivalent to the corresponding Rp thiophosphate analog) is formed in the backbone-modified 14mer. Thermally induced helix-coil transitions were monitored for the hybridized duplexes using UV and circular dichroism (CD) spectroscopy. The CD spectra of the two types of boron-modified hybrids closely resemble the unmodified parent duplex, forming B-type helices in 150 mM NaCl, 1 mM EDTA, 10 mM phosphate, pH 7.4, buffer. UV melting results indicate that both hybrids have stabilities comparable with the parent duplex as measured by Tm or delta G degree 25. These studies indicate that singly modified base- or backbone-boronated DNA are good analogs of normal DNA.

Platelet-derived growth factor-B increases colon cancer cell growth in vivo by a paracrine effect

PDGF-B released from colon tumor cells regulated tumor growth in athymic mice in a paracrine manner by inducing blood vessel formation. A positive correlation was found between expression of PDGF B-chain in cells grown in vitro and the number of factor VIII-positive blood vessels in tumors induced by three classes of colon carcinoma cell lines. Elevated expression of PDGF-B was also correlated with tumor size. Each cell line had the same mutations in the colon cancer genes APC, DCC, and p53 and had wild type c-K-ras genes (Huang et al. [1994] Oncogene, 9:3701-3706.) eliminating the possibility that any differences in tumor blood vessel formation were due to mutations and/or deletions in these genes. Colon carcinoma cells released biologically active PDGF capable of stimulating the growth of NIH3T3 cells, which was inhibited by neutralizing antisera to PDGF-AB chains. An inverse correlation was found between induction of factor VIII-positive blood vessels and expression of vascular endothelial growth factor (VEGF), while no correlation was seen with expression of either TGF alpha or k-FGF. Basic fibroblast growth factor (FGF) expression was not detected in these tumor cells. TGF beta 1 was capable of inducing PDGF-B expression in the undifferentiated U9 colon carcinoma cell line, but this sensitivity was not seen in differentiated cells. In contrast, TGF beta 1 inhibited VEGF expression in both undifferentiated cells and differentiated colon cancer cells. Thus, TGF beta 1 has two roles in the growth of undifferentiated U9 colon carcinoma cells in vivo: direct stimulation of cell proliferation as we have showed in earlier studies, and an increase in angiogenesis by inducing PDGF-B.

[Detection of estrogen receptor messenger ribonucleic acid in normal and ovariectomized rat bone]

Using ovariectomized female SD rats (OVX) as animal osteoporosis models, RNA samples were extracted directly from rat bone. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to examine the estrogen receptor (ER) messenger RNA (mRNA) level of expression in normal and OVX rat bone tissue. Results demonstrated that the rat ER gene is expressed in normal rat bone. DNA sequencing showed 300 bases sequence. We found that the OVX rats showed a sharp decrease in ER mRNA level when estrogen was reduced after ovariectomy and the expression of bone ER mRNA increased during estradiol therapy, suggesting that the expression of bone ER mRNA relies upon the level of estrogen. In addition, ER plays a very important role in the pathogenesis by means of its gene regulatory functions.

N7-cyanoborane-2'-deoxyguanosine 5'-triphosphate is a good substrate for DNA polymerase

The 5'-triphosphate of the boronated nucleoside analog N7-cyanoborane-2'-deoxyguanosine (7bdGTP) was synthesized, and a series of experiments was initiated to assess the potential of the compound to serve as a substrate for DNA polymerases. We show here that 7bdGTP can be incorporated into DNA by Sequenase. The resulting hemiboronated extension products are resistant to cleavage by treatment with either DMS and heat or a number of restriction enzymes. Further, in the polymerase chain reaction, 7bdGTP can be utilized as a substrate for Taq polymerase. Finally, by kinetic analysis, we have found that 7bdGTP is a more efficient substrate for exonuclease-free Klenow than normal dGTP. Thus, the introduction of a cyanoborane moiety to the N7 position of dGTP results in a nucleotide that is accepted in lieu of normal dGTP by a number of DNA polymerases.

Colon carcinoma cells with inactive nm23 show increased motility and response to motility factors

nm23H1 has properties of a metastasis suppressor gene. Although its mechanism of action is unknown, nm23 has been implicated in transforming growth factor beta 1 (TGF beta 1) signal transduction. In an earlier study we decreased nm23 mRNA levels 2- to 8-fold by antisense phosphorothiolated oligonucleotides in two HT29 colon carcinoma sublines at different stages in tumor progression with different responses to TGF beta 1: the HD3 subline, which shows TGF beta 1-induced growth arrest and differentiation; and the more tumorigenic U9 subline, whose growth and invasion are stimulated by TGF beta 1. Only TGF beta 1-mediated responses in HD3 cells were inhibited by nm23 antisense oligos, suggesting that nm23 functions in only one TGF beta 1 signaling pathway. In the current report we have extended this study to cell motility. HD3 motility was increased by nm23 phosphorothiolated antisense oligos which decrease nm23 mRNA levels, while HD3 cell motility was conversely decreased by TGF beta 1 which increases nm23 mRNA levels. HD3 motility was not increased by basic FGF, TGF beta 1 or TGF alpha, while the 13-fold higher basal motility of U9 cells was stimulated 3-fold by basic FGF, 4-fold by TGF beta 1 and 5-fold by TGF alpha, but not by scatter factor. Differences in motility and response to motility factors could not be ascribed to differences in either basal levels of proteases or modulation of their levels by TGF beta 1. Both HD3 and U9 cells displayed equal levels of urokinase activity and mRNA, equal expression of the metalloproteinase inhibitor TIMP-1, and no detectable collagenases by zymography. No differential response to TGF beta 1 was seen in any of these assays. Thus limited cell motility and lack of response to motility factors in HD3 colon cancer cells could be correlated with expression of nm23 active in signal transduction.

Colon absorptive epithelial cells lose proliferative response to TGF alpha as they differentiate

As colon epithelial cells migrate up the cylindrical colonic crypt, they terminally differentiate and lose their ability to divide. Elevated levels of the epithelial cell mitogen TGF alpha have been found at the top of the crypt by other investigators, causing us to speculate that colon epithelial cells lose mitogenic response to TGF alpha as they differentiate. We tested this hypothesis by using the HT29 colon carcinoma sublines U4 and U4H as models of one colonocyte lineage, fluid-transporting enterocytes. TGF alpha was mitogenic for the U4 cells, but inhibited the growth of the more differentiated U4H cells. However, p44 MAP kinase was activated by TGF alpha in both U4 and U4H cells, as well as in two control undifferentiated HT29 sublines which showed no change in proliferation in response to TGF alpha. In addition, TGF alpha activated the EGF receptor in each line by increasing its tyrosine phosphorylation. No relationship was found in these four lines between response to TGF alpha and level of expression of either the EGF receptor or two EGF receptor ligands, TGF alpha and amphiregulin. Activated EGF receptors initiate both growth-inhibitory and mitogenic signals in these cells since blocking some of the EGF receptors on TGF alpha-growth-inhibited U4H cells and TGF alpha-unresponsive U9 cells overrode the inhibitory signals and made both U9 and U4H cells sensitive to mitogenesis by added TGF alpha. These data imply that upon reaching stages of greater maturation, colon enterocytes lose proliferative response to TGF alpha because of changes in signaling by their EGF receptors.

Time of symptom onset of eight common medical emergencies

Specific time periods of the day may be associated with different frequencies of symptom onset in different diseases. The purpose of the current study was to examine times of symptom onset in eight commonly encountered emergent conditions--cerebral infarction, cerebral hemorrhage, transient ischemic attacks, cardiac dysrhythmias, angina pectoris, acute myocardial infarction, gastrointestinal bleeding, and acute asthma. Data from 4554 cases were retrospectively reviewed. Symptom onset frequency curve diagrams were derived, illustrating peak hours of symptom presentation for each of the eight emergent conditions. Hormonal and metabolic factors that may be related to diurnal variations in symptom onset of the eight diseases are briefly discussed.

Colon goblet cells lose proliferative response to TGF alpha as they differentiate

Two cell line models for colon goblet cells expressed 6- to 14-fold elevated levels of the EGF receptor, 3- to 5-fold levels of TGF alpha and 11- to 15-fold levels of amphiregulin compared with 2 cell lines which model colon enterocytic differentiation, suggesting a role for the EGF receptor and its ligands in goblet cell growth control. Two HT29 colon carcinoma sublines were used to model normal goblet cells at different stages of maturation. TGF alpha induced a 2-fold increase in growth of the HD8 subline but inhibited the growth of the more differentiated HD6 subline by 40%. EGF receptors were activated in each line by ligand, but signal transduction varied sharply. Both MAP kinase isoforms, p44 and p42, were markedly activated in HD8 cells for at least 20 min, while only a marginal activation was seen in HD6 cells. In contrast, the more differentiated HD6 cells showed an increase in 105 kDa MBP kinase activity with EGF treatment, while HD8 cells displayed constitutively elevated levels of this kinase. Thus, activated EGF receptors initiated different signalling pathways in model cell lines for colon goblet cells at different stages of maturation. TGF alpha protein levels have been shown by other investigators to be restricted to the top of the cylinder-like colonic crypt, where cells terminally differentiate and cease division, an unexpected location for an epithelial cell mitogen. Our data with model cell lines imply that normal colon goblet cells lose proliferative response to TGF alpha as they differentiate and the elevated levels of TGF alpha at the top of the colonic crypt in vivo serve to inhibit goblet cell growth.

An extensive subfrontal approach to the lesions involving the skull base

A modification of the transbasal approach of Dorome called extensive subfrontal approach and the surgical results with this approach in 22 cases are presented. Bilateral frontal craniotomies incorporated with the removal of orbital ridges and part of the orbital roofs were fashioned en bloc. It may give rise to good exposure of the midline lesions of the anterior, middle and posterior skull base, minimizing the need for the retraction of frontal lobes. There was no surgical mortality in this series of cases. Of the 20 cases with tumors, total resections were achieved in 11 cases, subtotal or large resections in 4 cases and partial resection in one case. Two patients with spontaneous rhinorrhea were successively treated surgically. 21 patients had a follow-up with a time ranging from 1-11 years (a mean of 3 years). 15 patients resumed their jobs with no evidence of recurrence of the original disease, and 5 patients able to live self-care. One patient with an olfactory neuroblastoma died 3 years after the operation owing to relapse of the tumor.

The effect of multiple blood conservation techniques on donor blood exposure in adult coronary and valve surgery performed with a membrane oxygenator: a multivariate analysis on 1310 patients

The object of the study was to retrospectively evaluate protective and risk factors for receiving donor blood products and red cell transfusions after coronary and valve surgery performed with a hollow-fiber oxygenator and with multiple blood-saving techniques. During the period of January 1991 to June 1993, 1310 patients underwent primary coronary and valve surgery using a hollow-fiber oxygenator at our institution; the mean age of this population was 61 +/- 10 years; 977 patients were men (74.6%). Of these patients, 73.5% (963/1310) underwent coronary, 21.5% (281/1310) valve, and 5% (66/1310) combined surgery. Two hundred seventy-six (21.1%) needed donor blood product transfusions, while 153 (11.7%) patients underwent red cell transfusions. Significant risk factors for homologous blood product exposure after multivariate logistic regression analysis were, in order of importance: (1) postoperative blood loss (O.R. = 1.0009 per mL, p = 0.0000); (2) cardiopulmonary bypass (CPB) time (O.R. = 1.008 per min, p = 0.0001); (3) age at intervention (O.R. = 1.031 per calendar year, p = 0.0026); and (4) reoperation for bleeding (O.R. = 1.71, p = 0.0078). Protective factors were: (1) male gender (O.R. = 0.56, p = 0.0000); (2) preoperative withdrawal of autologous blood (O.R. = 0.66, p = 0.0018); and (3) a preoperative hematocrit greater than 34% (O.R. = 0.76, p = 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Composite valve graft replacement of the ascending aorta and the aortic valve by a modified button technique: the influence of aortic pathology on early mortality and late survival

The risk factors for in-hospital mortality and mid-term survival in patients undergoing composite graft replacement of the aortic root with reimplant or coronary arteries by a modified button technique were evaluated with special emphasis on the underlying aortic pathology. Between 1985 and 1993 74 patients underwent replacement of the ascending aorta and the aortic valve following a modified button technique. The patients were divided into three groups according to aortic pathology: annuloaortic ectasia (43.58%), type A dissection (18.24%), and miscellaneous (13.18%). In-hospital mortality rates were 4.7%, 33.3% and 23.1%, respectively (P = 0.011). Univariate analysis showed that aortic pathology, NYHA class, emergency operation, redo operation, acute aortic dissection, preoperative cardiogenic shock, preoperative cardiac tamponade, longer cardiopulmonary bypass (CPB) and aortic cross-clamp times, and the need of femoral vein or femoral artery cannulation at intervention had univariate influence on in-hospital mortality. Multivariable stepwise logistic regression analysis identified CPB time odds ratio (OR) = 1.021/min, P = 0.007), the need of femoral vein cannulation at intervention (OR= 4.85, P = 0.008) and preoperative cardiac tamponade (OR = 3.11, P = 0.07) as independent predictors of in-hospital death. Follow-up ranged from 1 to 98 months (mean 39 +/- 30 months) with an actuarial survival rate of 75 +/- 9%, 52 +/- 13% and 67 +/- 14% at 5 years in annuloaortic ectasia, type A dissection, and miscellaneous patients, respectively (P = 0.18); when survival was evaluated in hospital survivors only, Kaplan-Meier survival rates were 77 +/- 9%, 79 +/- 14% and 89 +/- 10% at 5 years (P = 0.87). Comparing survival of annuloaortic ectasia patients (5-year survival 75 +/- 9%) versus survival of all other patients pooled together (5-year survival 55 +/- 11%), there was a statistically significant difference (P < 0.05); such a difference was no longer significant when comparing hospital survivors alone (5-year survival rate 77 +/- 9% annuloaortic ectasia patients vs 79 +/- 12% all other patients P = 0.61). Although aortic root replacement carries higher in-hospital mortality in some high-risk subgroups of patients, mid-term survival seems to be less affected by aortic pathology; high-risk patients are expected to have an out-hospital outcome comparable to the low-risk ones.