Timing of surgery after acute myocardial infarction

OBJECTIVE

We wished to determine if timing of surgery, when other co-morbid variables are controlled, influenced outcome after operations for acute myocardial infarction.

DESIGN

Between 3/20/1990 and 6/17/1994, data was prospectively collected on 338 patients undergoing operation for either evolving infarcts (n=73) or up to 21 days after infarction (mean 7.9 days).

SETTING

Tertiary hospital referral center.

PATIENTS

Infarction was diagnosed by CK enzymes or EKG Q-waves preoperatively in 338 patients undergoing surgery. The mean age of the patients was 66.1 years (SD+/-10.5 years), 76 had emergency operations immediately after catheterization (50 following PTCA complications), 223 had urgent operations, and 39 were elective.

INTERVENTIONS

Seventy-three had preoperative ballon pumps, and 259 had one or more mammary artery bypasses with a mean of 3.27 (SD+/-1.0) distal anastomoses.

RESULTS

In-hospital and 30-day survival rate was 95.6% (323/338). Of the 73 variables evaluated by step-wise logistic regression analysis, the multivariate independent preoperative predictors of death were: aortic valve regurgitation, chronic pulmonary disease, preoperative diuretic administration, preoperative balloon pump, preoperative inotropes, and the need for additional concomitant noncardiac surgery. Including the operative variables, the predictors were: preoperative balloon pump, preoperative inotropes, the presence of left main stenosis, preoperative renal failure, chronic pulmonary disease, valve disease, ischemic arrhythmia, pump perfusion time, valve surgery, and homologous blood transfusion volume required. When the postoperative variables were included, the predictors were: preoperative inotropes, postoperative balloon pump, postoperative epinephrine, postoperative permanent stroke, and postoperative acute renal failure. The time between infarction and operation was not an independent prediction (p>0.4) in any of the logistic regression models.

CONCLUSION

Early operation after acute infarction is not in itself a risk factor, rather comorbid disease and preoperative hemodynamic status determine outcome after surgery.

Cysteine-scanning mutagenesis of transmembrane domain XII and the flanking periplasmic loop in the lactose permease of EScherichia coli

Using a functional lactose permease mutant devoid of Cys residues (C-less permease), each amino acid residue in transmembrane domain XII and the periplasmic loop between putative helices XI and XII (loop XI/XII) was replaced individually with Cys. Out of 34 mutants, 31 exhibit 60-100% or more of C-less activity, mutants Gly377-->Cys and Leu385-->Cys exhibit lower rates of transport but accumulate lactose about 60-70% as well as C-less, and mutant Leu400-->Cys exhibits < 20% of C-less activity. Immunoblots reveal that all of the mutant proteins are present in the membrane in amounts comparable to that of C-less with the exception of mutants Gly377-->Cys and Leu385-->Cys which are expressed about 40% as well as C-less and mutant Leu400-->Cys which is hardly detectable. When transferred to the wild-type background, however, mutant Leu400-->Cys is expressed normally and exhibits highly significant transport activity. Finally, each active Cys-replacement mutant was assayed for sensitivity to N-ethylmaleimide, and with three exceptions, the mutants are essentially unaffected by the alkylating agent. Mutants Val367-->Cys, Gly370-->Cys, and Tyr373-->Cys which are predicted to be immediately distal to helix XI in loop XI/XII are significantly inactivated. The periodicity observed suggests that the periplasmic end of transmembrane domain XI may extend to position 373. In the following paper [Voss, J., He, M. M., Hubbell, W. L., & Kaback, H. R. (1996) Biochemistry 35, 12915-12918], site-directed spin labeling of single-Cys mutants at positions 387-402 is used to demonstrate that transmembrane domain XII is in an alpha-helical conformation.

Rescue of the horseradish peroxidase His-170-->Ala mutant activity by imidazole: importance of proximal ligand tethering

The proximal iron ligand in horseradish peroxidase (HRP) is His-170. The H170A mutant of polyhistidine-tagged HRP (hHRP) has been expressed in a baculovirus system and has been purified and characterized. At pH 7, the Soret maximum of the mutant is at 414 nm rather than 403 nm. Resonance Raman spectra indicate that the protein is primarily 6-coordinate low-spin in the ferric state with a band in the ferrous state at 212 cm-1 indicative of distal histidine coordination to the iron. Exogenous imidazole (Im) binds to the enzyme with Kd = 22 +/- 4 mM. Reaction of H170A hHRP with H2O2 does not give spectroscopically detectable compound I or compound II intermediates but results in gradual degradation of the heme group. Nevertheless, H170A hHRP is catalytically active, and its guaiacol and ABTS peroxidase activities are improved 260- and 125-fold, respectively, in the presence of saturating concentrations of Im. The Km for the stimulatory effect of Im is 24 mM for both guaiacol and ABTS. The pH profile of H170A hHRP differs from that of wild-type hHRP, but the differences are essentially eliminated by Im. The rate of formation of "compound I" for H170A hHRP, determined by steady state kinetic methods, is k1 = 16 M-1 s-1 without Im and k1 = 2.4 x 10(4) M-1 s-1 with Im. The corresponding rate for wild-type hHRP is k1 = 4.4 x 10(6) M-1 s-1. The results indicate that Im binds in the cavity created by the H170A mutation, coordinates to the heme iron atom, and restores a large part of the catalytic activity by rescuing the rate of compound I formation. However, this rescue of the catalytic activity by Im is possibly limited by coordination of the heme to the distal histidine (His-42) in the H170A mutant. Thus, a primary function of the proximal histidine is to tether the iron atom to disfavor sixth ligand binding, particularly coordination of the iron to the distal histidine. In addition, strong hydrogen bonding of the proximal ligand may be critical for facilitating O-O bond cleavage in the formation of compound I.

[Detection of immunoglobulin heavy chain (IgH) gene rearrangement in ANLL by polymerase chain reaction amplification and Southern blot]

Immunoglobulin heavy chain (IgH) gene rearrangement serves as a marker of clonality in B lymphoproliferative malignancies. In order to study the IgH rearranged gene in acute nonlymphoblastic leukemia (ANLL) patients we combine polymerase chain reaction (PCR) with Southern blot to detect 41 ANLL patients and 7 of them (17.1%) were found to have IgH rearrangement by PCR amplification. All these 7 positive cases were confirmed by Southern blot. The sensitivity of this method was 10(-4)-10(-5) level. In 12 patients with complete remission, 3 (25.0%) were found to have IgH rearranged gene. All these 3 cases had clinical relapse within 6 months. Our results show that IgH rearrangement not only may occur in lymphoblastic leukemia of B lineage, but also can be found in ANLL. The mechanism may be that in some ANLL patients, the leukemic transforming event might involve stem cells capable of both B cell and myeloid differentiation or ANLL might differentiate along different lineage with predominant appearance of one or the other subclone in the course of the disease.

[Screening for the new formulation of 25% ascorbic acid injection and studies on its stability]

Two optimum new formulation of 25% ascobic Acid injection were selected by screening with the method of orthogomal design. To estimate the stability of these new formulations, samples were subjected to accelerated stability test at elevated temperatures. The rats of coloration and variation in the concentration of the new formulation under anaerobic degradation were studied. Experimental results indicate that the rule of coloration of ascorbic acid injection may be represented by the following regression equation T = T(o)-kt2 where To is the initial transmittance of the injection, T denotes the transmittance at time t, and k denotes the regression coefficient. The variation in the concentration of the two new formulations under amaerobic degradation was found to proceed in the pseudo-zero order reaction. The discoloration and content of ascorbic acid for two injections were predicted by accelerated stability test with the classical isothermal method and one-point method respectively. The discoloration shelf-life was about 39 months for R I and 36 months for R II, the content shelf-life about 40 months for R I and 38 months for R II respectively.

Defining a novel cis-element in the 3'-untranslated region of mammalian ribonucleotide reductase component R2 mRNA. cis-trans-interactions and message stability

Mammalian ribonucleotide reductase is a highly regulated activity essential for DNA synthesis and repair. The 3'-untranslated region (3'-UTR) of mammalian ribonucleotide reductase R2 mRNA has been implicated in the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate-mediated stabilization of mouse BALB/c 3T3 R2 message. We investigated the possibility that the 3'-UTR contains regulatory information for R2 mRNA turnover. Using 3'-end-labeled RNA in gel shift and UV cross-linking analyses, we detected in the 3'-UTR a novel 9-nucleotide cis-element, 5'-UCGUGUGCU-3', which interacted with a widely distributed cellular cytosolic protease-sensitive factor(s) in a sequence-specific manner to form a 45-kDa R2 binding protein complex. The binding activity was redox-sensitive and down-regulated by 12-O-tetradecanoylphorbol-13-acetate and okadaic acid in a dose-dependent manner. Insertion of a 154-base pair fragment containing the cis-element led to markedly reduced accumulation of chloramphenicol acetyltransferase hybrid mRNA relative to the same insert carrying a series of G --> A mutations within this element that eliminated binding. We suggest that the 9-nucleotide region functions as a destabilizing element. These results provide a model for ribonucleotide reductase gene expression through a novel and specific mRNA cis-trans-interaction involving a phosphorylation signal pathway that leads to changes in the stability of R2 message.

Platelet endothelial cell adhesion molecule-1 (PECAM-1) homophilic adhesion is mediated by immunoglobulin-like domains 1 and 2 and depends on the cytoplasmic domain and the level of surface expression

PECAM-1/CD31 is vascular cell adhesion and signaling molecule of the Ig superfamily that plays a role in neutrophil recruitment at inflammatory sites and may be involved the release of leukocytes from the bone marrow and in cardiovascular development. The interactions of PECAM-1 with its ligands are complex in that it is able to bind both with itself (homophilic adhesion) or with non-PECAM-1 ligands (heterophilic adhesion). Although the factors that regulate ligand binding are not fully understood, these interactions are regulated in part by its large cytoplasmic domain, a region of 118 amino acids encoded by 8 exons of its gene (exons 9-16). The purpose of this work was to better define the mechanisms of PECAM-1-dependent homophilic adhesion by analyzing the binding interactions of L-cells expressing full-length and selectively mutated forms of human, murine, and human/murine chimeric PECAM-1 molecules in an established aggregation assay. These studies demonstrate that 1) the minimal length of the cytoplasmic domain required for cellular aggregation is represented within the sequences encoded by exons 9 and 10, 2) removal or addition of the sequences encoded by exon 14 from the cytoplasmic domain can determine whether the mechanism of aggregation is a heterophilic calcium-dependent process or a homophilic calcium-independent process, 3) high levels of surface expression of PECAM-1 on the cell surface change the mechanism of aggregation from heterophilic to homophilic, and 4) PECAM-1-dependent homophilic binding appears to involve the direct interaction of only the first two extracellular Ig-like domains. These data suggest that PECAM-1-ligand interactions can be regulated through multiple pathways including alterations of the cytoplasmic domain and the level of surface expression.

Preclinical trial of a bioartificial liver support system in a porcine fulminant hepatic failure model

BACKGROUND

This study describes the pre-clinical trials of an extracorporeal bioartificial liver support system (BALSS). It includes the biochemical changes which occur in the plasma and blood of pigs with devascularized livers when the plasma is treated in a BALSS, and the testing of the system for presence or absence of infective agents, pyrogens and for toxicity.

METHODS

Hepatic cells were prepared from littermate juvenile white landrace pigs with a double-step collagenase digest technique. The cell preparations were incubated with collagen-coated dextran microspheres (CDM) for 3 h and the medium was tested to determine cellular metabolic activity. Incubation continued for a further 20 h during which the hepatic cells attach to the CDM. The CDM-attached cells were inoculated into a hollow fibre bioreactor which was part of an extracorporeal liver support system.

RESULTS

Hepatic cell content of the bioreactor was 6 x 10(9) +/- 3 x 10(8) cells, equivalent to those present in half a pig's liver. The system was tested in a controlled trial with the plasma of pigs with fulminant hepatic failure (FHF) due to devascularized livers. When plasma from FHF pigs was circulated through the device there was significantly less of an increase in the accumulation of ammonia, lactate and most amino acids when hepatic cells were included in the circuit compared with those in control experiments when they were excluded. Similar changes occurred in procine blood. There were few infections diagnosed and an absence of pyrogens, endotoxins and toxicity in the bioreactor contents or in the terminating reservoir or animal blood samples.

CONCLUSIONS

We believe that the results, demonstrating function of the porcine hepatic cells in the circuit, together with low risks, justify a clinical trial of use of the BALSS in Australia.

[Determination of serum free amino acids and ammonia in pregnant women with severe pregnancy induced hypertension]

OBJECTIVE

To determine the changes of serum free amino acids and ammonia in pregnant women with severe pregnancy induced hypertension (PIH) and to evaluate its significance.

METHODS

16 kinds of free amino acids and ammonia in maternal serum were measured by auto-amino acid-analyzor in 33 cases with severe PIH and 29 normal pregnancies. Haematocrit (HCT) and hemoglobin (Hb) in some of the samples were also determined. The correlation between HCT, Hb and the total free amino acid were studied.

RESULTS

The group with PIH showed the following changes: amino acidemia and ammonemia; high aromatic amino acidemia; high threonine, arginine, glycine, cystine and glutamic acidemia. The level of glutamic acid was obviously higher in the eclampsia patients than that in the preeclampsia ones. There existed a negative correlation between the quantities of the total amino acid and HCT and Hb in PIH group.

CONCLUSION

There were amino acidemia and ammonemia in PIH patients. The high levels of some amino acids might be related with the pathogenesis of hypertension and the cerebral symptoms.

A non-parametric test for interval-censored failure time data with application to AIDS studies

Interest often centres on the comparison of failure time distributions based on interval-censored failure time data such as in the work by Finkelstein, in which she proposed a score test under continuous proportional hazards model. In this article, we consider a different situation in which the underlying failure time is a discrete variable or the observed times correspond with a discrete scale. To compare failure time distributions in these situations, we propose a non-parametric test, a generalization of the usual logrank test for right-censored failure time data. Simulation results indicate that the test performs satisfactorily.

Characterization of manganese(II) binding site mutants of manganese peroxidase

A series of site-directed mutants, E35Q, E39Q, and E35Q-D179N, in the gene encoding manganese peroxidase isozyme 1 (mnp1) from Phanerochaete chrysosporium, was created by overlap extension, using the polymerase chain reaction. The mutant genes were expressed in P. chrysosporium during primary metabolic growth under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The mutant manganese peroxidases (MnPs) were purified and characterized. The molecular masses of the mutant proteins, as well as UV-vis spectral features of their oxidized states, were very similar to those of the wild-type enzyme. Resonance Raman spectral results indicated that the heme environment of the mutant MnP proteins also was similar to that of the wild-type protein. Steady-state kinetic analyses of the E35Q and E39Q mutant MnPs yielded K(m) values for the substrate MnII that were approximately 50-fold greater than the corresponding K(m) value for the wild-type enzyme. Likewise, the kcat values for MnII oxidation were approximately 300-fold lower than that for wild-type MnP. With the E35Q-D179N double mutant, the K(m) value for MnII was approximately 120-fold greater, and the kcat value was approximately 1000-fold less than that for the wild-type MnP1. Transient-state kinetic analysis of the reduction of MnP compound II by MnII allowed the determination of the equilibrium dissociation constants (KD) and first- order rate constants for the mutant proteins. The KD values were approximately 100-fold higher for the single mutants and approximately 200-fold higher for the double mutant, as compared with the wild-type enzyme. The first-order rate constants for the single and double mutants were approximately 200-fold and approximately 4000-fold less, respectively, than that of the wild-type enzyme. In contrast, the K(m) values for H2O2 and the rates of compound I formation were similar for the mutant and wild-type MnPs. The second-order rate constants for p-cresol and ferrocyanide reduction of the mutant compounds II also were similar to those of the wild-type enzyme.

Transformation of NIH 3T3 cells by HER3 or HER4 receptors requires the presence of HER1 or HER2

Members of the epidermal growth factor receptor (EGFR) subfamily of receptor protein tyrosine kinases have been implicated in the pathogenesis of various malignancies. The ability of one EGFR subfamily member to influence, or function synergistically with, another is likely to be a general feature of these receptors. To assess the role of receptor heterodimerization, we analyzed the ability of Neu differentiation factor (NDF) to induce cell growth and transformation of NIH 3T3 cells transfected with different combinations of the EGFR subfamily of receptors. NDF induced mitogenesis, but not transformation, of cells expressing either HER3 or HER4 alone. However, NDF-induced cell transformation was observed when either HER1 or HER2 was coexpressed with HER3 or HER4. In analogous receptor phosphorylation experiments, NDF-induced transphosphorylation appears to be correlated with synergistic transformation of NIH 3T3 cells. Interestingly, transphosphorylation between HER1 and HER4 can be stimulated by either EGF or NDF.

Molecular characterization of VDJ transcripts from a newborn piglet

The sequences of 42 transcripts, expressed with IgM, IgG and IgA and cloned from the mesenteric lymph node of a newborn piglet, are described. Forty transcripts used either DHA and DHB and their FR4 were identical to the single swine germline JH. The low frequency of somatic mutation made it possible to identify 35/41 as originating from five putative germline VH genes, of which VHA, VHB and VHC accounted for > 85%. The remaining six transcripts were hybrids of these five germline genes. The most 3' functional VH gene (VH2 = VHB) was the only one exclusively expressed with IgM although VHA, of unknown location in the genome, accounted for half of all transcripts. Junctional diversity in CDR3 was extensive and asymmetrical, in that D-J joining contributed more diversity than V-DJ joining. Reading frame II was used twice as frequently as frame III and the CDR3 generated using the former would have a higher expected R/S ratio. This study indicated that the expressed VH repertoire of the newborn piglet is restricted and nearly germline although junctional diversity is mature and better developed than in fetal mice. The hybrid clones suggest that swine compensate for their < 20 VH genes and single JH by using somatic gene conversion. There was no evidence for exclusive or preferential expression of the most 3' VH gene as occurs in chickens and rabbits respectively, and switching to downstream constant regions probably occurs in utero, even in the theoretical absence of environmental antigens and maternal regulatory molecules. Preferential VHA expression is probably a selection phenomenon.

[Evaluation of radiotherapy for state I ovarian carcinoma]

To investigate the role of radiotherapy for stage I epithelial ovarian carcinoma, the results in 91 patients treated from 1970-1989 were retrospectively analysed. There were 60 patients treated by operation combined with chemotherapy, 31 patients by operation combined with chemotherapy and radiotherapy. Patients in both groups were comparable with regard to age, clinical stage, histology grade, type of operation and chemotherapeutic regimen. The 5-year actuarial survival rate was 78.3% for those receiving additional radiotherapy and 72.4% for those without additional radiotherapy. The recurrence rate was 32.2% with a median recurrence time of 34 months in the former group while 60.6% and 18.6% months for the latter. Radiotherapy did not confer survival advantage in the treatment of stage I ovarian cancer, but it could decrease recurrence rate and delay onset of recurrence.

Tolerance to rat liver allografts. III. Donor cell migration and tolerance-associated cytokine production in peripheral lymphoid tissues

The aim of this work was to investigate the mechanism of spontaneous rat liver allograft tolerance. Liver allografts from a LEW donor into DA recipient (LEW-->DA) or of PVG-->DA were spontaneously tolerated (TOL) across a complete MHC mismatch. In contrast, DA-->LEW or PVG-->LEW liver allografts were rejected in 10 to 15 days (REJ). We examined whether donor cell migration to recipient lymphoid tissues might be associated with TOL. Many donor cells were observed in draining (celiac) lymph nodes (LN) and spleen, reaching a peak on day 1 and then decreasing rapidly thereafter. Irradiation of liver donors, which we have previously shown to delete tolerance, significantly reduced the number of donor leukocytes in recipient lymphoid tissues. While this suggested an association between donor cell migration and tolerance, the number, distribution, and type of donor cells in recipient lymphoid tissues of REJ was similar to those of TOL. Expression of cytokine mRNA in LN and spleen showed an early increase in the expression of IL-2 and IFN-gamma mRNA on day 1 and then a rapid decrease to constitutive levels. Spleen and LN levels of IL-6, IL-10, TNF-alpha, or TGF-beta mRNA showed much less up-regulation than IL-2 or IFN-gamma. Paradoxically, there was greater expression of IL-2 and IFN-gamma mRNA in TOL lymphoid tissues than in REJ, and this superinduction was partially prevented by donor irradiation. Superinduction of IL-2 and IFN-gamma was, therefore, more closely associated with TOL than was donor cell migration. This was confirmed by treatment of TOL recipients with a short course of methylprednisolone, which reduced survival of subsequent donor strain skin grafts. This finding has implications for treatment of human liver transplants and is evidence for a novel pathway of transplant tolerance.

Tolerance to rat liver allografts. III. Donor cell migration and tolerance-associated cytokine production in peripheral lymphoid tissues

The aim of this work was to investigate the mechanism of spontaneous rat liver allograft tolerance. Liver allografts from a LEW donor into DA recipient (LEW--&gt;DA) or of PVG--&gt;DA were spontaneously tolerated (TOL) across a complete MHC mismatch. In contrast, DA--&gt;LEW or PVG--&gt;LEW liver allografts were rejected in 10 to 15 days (REJ). We examined whether donor cell migration to recipient lymphoid tissues might be associated with TOL. Many donor cells were observed in draining (celiac) lymph nodes (LN) and spleen, reaching a peak on day 1 and then decreasing rapidly thereafter. Irradiation of liver donors, which we have previously shown to delete tolerance, significantly reduced the number of donor leukocytes in recipient lymphoid tissues. While this suggested an association between donor cell migration and tolerance, the number, distribution, and type of donor cells in recipient lymphoid tissues of REJ was similar to those of TOL. Expression of cytokine mRNA in LN and spleen showed an early increase in the expression of IL-2 and IFN-gamma mRNA on day 1 and then a rapid decrease to constitutive levels. Spleen and LN levels of IL-6, IL-10, TNF-alpha, or TGF-beta mRNA showed much less up-regulation than IL-2 or IFN-gamma. Paradoxically, there was greater expression of IL-2 and IFN-gamma mRNA in TOL lymphoid tissues than in REJ, and this superinduction was partially prevented by donor irradiation. Superinduction of IL-2 and IFN-gamma was, therefore, more closely associated with TOL than was donor cell migration. This was confirmed by treatment of TOL recipients with a short course of methylprednisolone, which reduced survival of subsequent donor strain skin grafts. This finding has implications for treatment of human liver transplants and is evidence for a novel pathway of transplant tolerance.

Magnesium activated adenosine formation in intact perfused heart: predominance of ecto 5'-nucleotidase during hypermagnesemia

Magnesium ion is an allosteric effector of 5'-nucleotidase and thus activates adenosine production from AMP. Two distinct 5'-nucleotidase systems, the membrane-bound ecto and the soluble cytosolic isoforms, exist in mammalian myocardium. The aim of this study was to delineate the contributions of the ecto vs. cytosolic isoforms to Mg2+-stimulated cardiac purine nucleoside formation and release. Isolated guinea pig hearts were retrogradely perfused at their physiological aortic pressure with Krebs-Henseleit bicarbonate buffer fortified with 10 mM glucose. AMP and the adenylate degradatives adenosine and inosine were measured in coronary venous effluent and in epicardial transudate, which was sampled to estimate concentrations of adenylate degradatives in the interstitium. When perfusate Mg2+ was increased from 0.6 to 6 mM, coronary vascular resistance and spontaneous heart rate fell, and steady-state coronary venous release of adenosine + inosine rose severalfold. Cytosolic free magnesium, as estimated by 31P-NMR after 15 min of perfusion with 6 mM Mg2+ or from chemically measured indicator metabolites after 30 min, rose 60 and 144% respectively (P < 0.05). Excess Mg2+ stimulated purine nucleoside release nearly threefold in coronary venous effluent and four- to sevenfold in epicardial transudate. 50 microM, alpha,beta-methylene adenosine 5'-diphosphate (AOPCP), a selective inhibitor of ecto 5'-nucleotidase, elevated interstitial AMP concentration tenfold, did not attenuate basal nucleoside release, but completely inhibited Mg2+-stimulated coronary venous purine nucleoside release and blunted Mg2+-stimulated interstitial purine nucleoside formation by 69%. During perfusion with exogenous 1 microM [8-14C]AMP, excess perfusate MgCl2 increased [14C]adenosine release by 63% in coronary effluent and 133% in epicardial transudate. AOPCP decreased baseline [14C]adenosine release in coronary effluent and epicardial transudate by 85-90%, caused equilibration of arterial and epicardial AMP, and attenuated MgCl2 activation of p[14C]adenosine formation by approx. 75%, in both the vascular and interstitial compartments. Intramyocytic concentrations of allosteric regulators of the cytosolic 5'-nucleotidases were evaluated in stop-frozen myocardium. Excess magnesium did not appreciably alter intracellular pH and ATP concentration, but lowered free cytosolic ADP and AMP concentrations by 50 and 70%, respectively. A simplified model of compartmentalized adenosine metabolism is proposed in which magnesium ion-activated cardiac purine release originates predominantly from the ecto 5'-nucleotidase; magnesium ion stimulation of metabolic flux through the cytosolic isoforms was constrained by concomitant reductions in intracellular AMP substrate and allosteric activator ADP. Magnesium ion-enhanced adenosine formation by 5'-nucleotidase could contribute to the known cardioprotective effects of this clinically used cation.

Modulation of integrin expression in endometrial stromal cells in vitro

Integrins, a class of cell adhesion molecules found on virtually all cells, display dynamic temporal and spatial patterns of expression in the endometrium during the menstrual cycle and in early pregnancy. To study integrin regulation, we measured the expression of eight different integrin subunits on cultured human endometrial stromal cells obtained from proliferative phase endometrium, using immunofluorescence and flow cytometry. Treatment with estrogen and progesterone induced hormonal changes of decidualization but did not alter the expression of any of the integrins. It is presently unknown whether steroid hormones other than estrogen or progesterone affect integrin expression. In contrast, treatment with several growth factors and cytokines resulted in specific alterations of integrin levels. Epidermal growth factor, transforming growth factor-alpha, and transforming growth factor-beta 1 induced expression of the alpha 1 beta 1 collagen/laminin receptor. There also was a trend towards decreased expression of the alpha 6 subunit in response to interleukin-1 alpha, interleukin-1 beta, and tumor necrosis factor-alpha. The expression of alpha 1 beta 1 was accompanied by increased adhesion to collagen but there was no change in the binding to fibronectin and vitronectin. Our findings suggest that some aspects of decidualization may be regulated by steroid hormones, whereas others, such as integrin expression, are regulated by cytokines or growth factors, possibly of trophoblast origin. Integrins are likely to play a role in the interaction between trophoblast and endometrium.

Nonparametric tests of tumor prevalence data

This note discusses the statistical analysis of tumor prevalence data arising from tumorgenicity experiments with focus on the comparison of different treatments. In this situation, the commonly used tests can be classified into two types: interval-based tests and model-based tests (Hoel, D. G. and Walburg, H. E., 1972, Journal of the National Cancer Institute 49, 361-372; Dinse, G. E. and Lagakos, S. W. 1983, Applied Statistics 32, 236-248). It is known that the results obtained from the interval-based tests may vary according to the choice of intervals and, for the model-based tests, it may be difficult to justify the assumed model. A computationally simple alternative to these tests is proposed; this alternative is not interval-based and makes no strong model assumption. The results of a simulation study comparing the proposed test with other tests are presented and suggest that the proposed approach is quite satisfactory.

A phospholipid acts as a chaperone in assembly of a membrane transport protein

A mutant of Escherichia coli lacking phosphatidylethanolamine (PE) and a monoclonal antibody (mAb 4B1) directed against a conformationally sensitive epitope (4B1) of lactose permease were used to establish a novel role for a phospholipid in the assembly of a membrane protein. Epitope 4B1 is readily detectable in spheroplasts and right-side-out membrane vesicles from PE-containing but not from PE-deficient cells expressing lactose permease. Lactose permease from PE-containing membranes, but not from PE-deficient membranes, subjected to sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and Western blot analysis is also recognized by mAb 4B1. If total E. coli phospholipids or PE (but not phosphatidylcholine, phosphatidylglycerol, or cardiolipin) are blotted on nitrocellulose sheets (Eastern blot) prior to transfer of proteins from SDS-polyacrylamide gels, the permease from PE-deficient cells regains its recognition by mAb 4B1. Therefore, PE is required during assembly to form epitope 4B1, but, once formed, sufficient "conformational memory" is retained in the permease to either retain or reform this epitope in the absence of PE. Lactose permease lacking epitope 4B1 can be induced to form the epitope if partially denatured and then renatured in the presence of PE specifically. These results establish for the first time a role for PE as a molecular chaperone in the assembly of the lactose permease.

[Early changes in cardiac function and beta-ARs in heart after severe scalds in rat]

The changes in left ventricular function and ventricle beta-adrenoceptors (beta-ARs) were measured in rat undergoing a full thickness scalded burn of skin of 30% total body surface area. The results showed that there were a significant decrease in left ventricular systolic pressure (LVSP), maximum rising and falling rate of left intraventricular pressure (LV +/- dp/dtmax) and density of ventricular beta-ARs. Correlation analysis showed that the change in beta-ARs density correlated with the change in LVSP, LV +/- dp/dtmax positively.

Molecular markers of ionizing radiation-induced gene mutations in mammalian cells

We have isolated independent Chinese hamster ovary (CHO) cell mutants at the hypoxanthine guanine phosphoribosyltransferase (hprt) locus from untreated, 60Co gamma-ray-exposed, and 212Bi alpha-exposed cells and identified the molecular changes underlying the mutation determined by multiplex polymerase chain reaction (PCR)-based exon deletion analysis. Both the parental CHO-K1 cells and the X-ray-sensitive mutant xrs-5 cells were studied. The radiosensitive xrs-5 cells are defective in DNA double-strand break rejoining ability and in V(D)J recombination, which can be complemented by Ku protein. Of the 71 spontaneous CHO-K1 hprt mutants analyzed, 78% showed no change in exon number or size, 20% showed loss of one to eight exons (partial deletion), and 3% showed loss of all nine hprt exons (total deletion). Exposure of CHO-K1 cells to 6 Gy of gamma rays, which reduced survival levels to 10%, produced a high deletion spectrum with 45% of the 20 mutants analyzed showing a loss of one to eight exons and 30% showing total deletion. Exposure to an equitoxic dose of alpha radiation from 212Bi, a 220Rn daughter, resulted in a spectrum similar to the gamma-ray spectrum in that 75% of the 49 mutants analyzed were deletions. To alpha radiation, however, tended to produce larger intragenic deletions than gamma radiation. Of the 92 spontaneous xrs-5 mutants analyzed for deletions, 43% showed a loss of one to eight exons and 14% showed total deletion. This suggests that, in certain regions of the hprt gene, base alterations can be converted into large deletions and alteration in the Ku protein complex can influence this type of mutational process. Exposure to alpha radiation (10% survival) to xrs-5 cells resulted in a deletion spectrum similar to that seen in CHO-K1 cells. Of the 49 mutants analyzed, 43% showed on change in exon number or size, 16% showed a loss of one to eight exons, and 41% showed total deletion. While the defect in xrs-5 cells has a profound effect on spontaneous mutant spectra, this defect does not appear to affect alpha-induced mutation spectra.

[Ovarian metastasis in uterine cervical cancer: analysis of 17 cases]

OBJECTIVE

To investigate the incidence of ovarian metastasis in cervical cancer, especially in early FIGO stages.

METHODS

Seventeen cervical cancer patients with ovarian metastasis treated at Cancer Hospital, Chinese Academy of Medical Sciences from 1958 to 1994 were retrospectively analysed. The diagnoses of all patients were confirmed by operations and pathologic examinations.

RESULTS

The incidence of ovarian metastasis in cervical cancer was 0.07% in squamous cell carcinoma and 1.81% in adenocarcinoma (P < 0.05). In early stages (stage l-I), the incidence of ovarian metastasis in adenocarcinoma was higher than that in squamous cell carcinoma (2.2% VS 0.08%, P < 0.05). In patients treated by surgery, the rate of ovarian metastasis in adenocarcinoma was also higher than that in squamous cell carcinoma (7.8% VS 1.6%, P < 0.05). 10 of the 17 cases had macroscopic metastasis and 7 had microscopic metastasis. 11 patients (58.8%) were with bilateral ovarian involvement. Uterine corpus invasion and retroperitoneal lymph node involvements were high risk factors for ovarian metastasis in cervical cancer. The prognosis of cervical cancer patients with ovarian metastasis was poor, the 5-year survival rate in this study being only 17.6%.

CONCLUSIONS

Patients with cervical cancer are threatened with the risk of ovarian metastasis, especially in adenocarcinoma. Conservative treatment of the cervical cancer with reservation of the ovary should be further investigated.

CWR22 xenograft as an ex vivo human tumor model for prostate cancer gene therapy

BACKGROUND

Lack of well-defined relevant in vivo or in vitro tumor models is one of the major limitations in assessing candidate therapeutic regimens, especially gene therapy, for prostate cancer. Since gene therapy is emerging as a potentially powerful therapeutic modality, it is desirable to evaluate this approach for the treatment of human prostate cancer.

PURPOSE

We sought to establish a relevant ex vivo tumor model for gene therapy studies of human prostate cancer.

METHODS

We constructed and established a transgenic human tumor model consisting of three major components: 1) human primary prostate cancer cells, CWR22, reactivated for growth after storage in liquid nitrogen; 2) a collagen gel ex vivo tissue culture system useful for short-term maintenance and manipulation of CWR22 cells under in vitro experimental conditions; and 3) a high-velocity, particle-mediated gene transfer system that is highly efficient in the ex vivo transfection of target cells. Prostate-specific antigen (PSA) levels in the cell culture media were monitored after transfecting CWR22 cells with candidate therapeutic genes, including the cytokines human interleukin 2 (IL-2) and granulocyte-macrophage colony-stimulating factor (GM-CSF), both as complementary DNAs [cDNAs]). CWR22 cells, transfected with firefly luciferase cDNA as a reporter gene, served as control cells for cytokine gene expression. CWR22 cells, transfected with the bacterial beta-galactosidase cDNA as a reporter gene, were used to assess the efficiency of gene transfer. Transcription of each of the cDNAs was driven by the cytomegalovirus (CMV) early gene promoter.

RESULTS

The three-dimensional organization of tumor cells and functional characteristics of human prostate cancers were maintained in this ex vivo model of prostate cancer. Candidate therapeutic genes, CMV-IL-2 and CMV-GM-CSF, were expressed at peak levels of up to 38 ng of protein per 10(6) cells every 24 hours. IL-2 and GM-CSF secretion was sustained at approximately 40%-50% of peak levels during the entire experimental period (9-10 days in culture). At 7 days after gene delivery, a more than twofold reduction in the secretion of PSA was detected in the IL-2 (3.8 +/- 1.3 ng/10(4) cells every 24 hours [mean +/- standard deviation]) or GM-CSF (4.0 +/- 1.7 ng/10(4) cells every 24 hours) cDNA transfected cells as compared with the control cells transfected with luciferase cDNA (9.3 +/- 1.0 ng/10(4) cells every 24 hours). Up to 10% of the cells transfected with beta-galactosidase cDNA expressed measurable beta-galactosidase activity.

CONCLUSION

This study demonstrated an efficient, rapid, and reliable system for gene transfer and expression in primary human prostatic carcinoma cells maintained in a collagen gel culture system.

IMPLICATIONS

Our findings suggest a broad application of this CWR22 xenograft primary culture system as an ex vivo tumor model for the evaluation and characterization of various candidate therapeutic genes for human prostate cancer gene therapy, including a cytokine gene-modified tumor vaccine strategy.

Purification and functional characterization of the C-terminal half of the lactose permease of Escherichia coli

The lactose permease has been expressed in contiguous, non-overlapping polypeptide fragments containing the N-terminal (N6) and C-terminal (C6) transmembrane domains of the protein [Bibi, E., & Kaback, H. R. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 4325; Zen, K., et al. (1994) Biochemistry 33, 8198]. When expressed individually, N6 and C6 are unstable and do not catalyze active transport. However, when expressed simultaneously, the polypeptides stabilize each other and form a complex that catalyzes active lactose transport. Moreover, a deletion construct containing the first transmembrane domain and the six C-terminal transmembrane domains mediates downhill lactose translocation [Bibi et al. (1991) proc. Natl. Acad. Sci. U.S.A. 88, 7271]. Here we report that C6 can be expressed independently in a relatively stable form that binds monoclonal antibodies 4B1 and 4B11, which interact with conformationally dependent epitopes on the periplasmic and cytoplasmic surfaces of the membrane, respectively. In addition, C6 retains the ability to catalyze lactose translocation down a concentration gradient in a specific manner. Finally, as observed with full-length Val331Cys permease, beta-D-galactopyranosyl 10thio-beta-D-galactopyranoside quenches the fluorescence of 2-(4'-maleimidylanilino)naphthalene- 6-sulfonic acid (MIANS)- labeled C6 with a single-Cys residue in place of Val331, exhibiting as apparent Kd of 0.2 mM. Unlike full-length Val331Cys permease, however, ligand does not induce a chance in the position of the emission maximum of MIANS-labeled C6(Val331Cys) permease not in the reactivity of C6 (Val331Cys) permease with MINAS. the results indicate that C6 retains a conformation similar to that on the native permease and that most of the structure required of high-affinity binding and substrate translocation is located in the C-terminal half of the molecule.

[Experimental study on adenosine hypothesis of bradyarrhythmias occurring in myocardial hypoxia and its clinical significance]

Important role of endogenous adenosine in the pathogenesis of hypoxic bradyarrhythmias was verified experimentally both in vivo and in vitro models of myocardial hypoxia in 180 guinea pigs and 40 rabbits by using enzyme differential spectrophotometry, synchronous quantitative analysis of correlated factors and adenosine antagonist. Results disclosed that endogenous adenosine in hypoxic myocardium increased markedly from a gram myocardial tissue 5.8 +/- 1.7 nmol of the control group to 27.5 +/- 2.0 nmol of 5% O2 inhalation group (P < 0.01). Sinus bradycardia and A-V block induced by injection of exogenous adenosine were closely akin to those caused by myocardial hypoxia both in ECG characteristics and dose-response curve. Both of their His electrograms showed prolongation of A-H interval but nochange of H-V interval, indicating the same locality of conduction block. Synchronous quantitative analysis of 3 related factors revealed a correlation coefficient of 0.99 (P < 0.01) between endogenous adenosine and bradyarrhythmias, denoting a subordinate instead of coordinate relation. Moreover, cause and effect relation could be shown between them from the result that aminophylline (50 mg, i.p.) could abolish completely II degrees-III degrees A-V block which would otherwise be bound to occur after inhalation of 5% O2. The present study is the first in vivo experimental verification of adenosine hypothesis throughout the world which not only can well explain those atropine-resistant cases, but also opens up the way to an entirely new therapeutic strategy for these kinds of bradyarrhythmias, i.e. instead of M-cholinoceptor blocker, adenosine antagonist (methylxanthines, e.g. aminophylline) should be prescribed.

Purification, characterization and cDNA cloning of a novel anticoagulant of the intrinsic pathway, (prolixin-S) from salivary glands of the blood sucking bug, Rhodnius prolixus

The salivary glands of the blood sucking insect, Rhodnius prolixus, have an anticoagulant, prolixin-S, which was reported as a specific inhibitor of intrinsic coagulant pathway. Prolixin-S was purified from the salivary glands extract of Rhodnius prolixus by gel filtration and anion exchange HPLC by assaying prolongation of activated partial thromboplastin time (APTT). The isolated protein specifically inhibited factor IXa-catalyzed activation of factor X in the presence of Ca2+ and phospholipids irrespective of the presence or absence of factor VIIIa. The anticoagulant factor had red color and a specific absorbance peak at 402 nm and thus it was identified as a heme protein. A Rhodnius prolixus salivary gland cDNA library was prepared, screened with an antibody against prolixin-S and its complete cDNA sequence was determined. cDNA and deduced amino acid sequences showed that prolixin-S is a novel anticoagulant of 19,922 Da, which has no sequence homology with any other anticoagulant reported so far.

The influence of surface slope on human gait characteristics: a study of urban pedestrians walking on an inclined surface

Human locomotion on inclined surfaces has been little studied. This work investigated uphill and downhill walking of urban pedestrians on slopes of up to 9 degrees. During a 3-month period, the gait characteristics of 1200 female and 1200 male pedestrians were recorded as they traversed a ramp of naturally varying slope at Sydney's Circular Quay. Walking speed, cadence and step length were determined for each subject, and average population gait parameters, for each ramp angle, were also calculated. The most significant finding was that the pedestrians' step length was decreased during ramp descent. Since theoretical analysis concludes that a reduction in step length produces a reduction in the friction demand, a shortening of the stride length is probably a means of counteracting the higher friction demand that would otherwise be required at heel strike during downhill walking.

Endometrial progesterone receptors and markers of uterine receptivity in the window of implantation

OBJECTIVE

To compare the expression of endometrial P receptors (PR) levels with markers of endometrial receptivity during the window of implantation.

DESIGN

Prospective, controlled study to examine endometrial PR and three cycle-specific integrins in endometrial biopsies obtained during the window of implantation.

SETTING

An academic teaching hospital.

PATIENTS

One hundred seventy-five endometrial biopsies from regularly cycling women with luteal phase defect (LPD; group 1; n = 80), medically treated LPD (group 2; n = 16), minimal and mild endometriosis with aberrant alpha v beta 3 expression (group 3; n = 21), fertile controls (group 4; n = 26), and infertile controls (group 5; n = 32).

MAIN OUTCOME MEASURE

Immunohistochemical staining intensity of each antigen using the semi-quantitative grading system (HSCORE), compared using analysis of variance with Scheffe's correction.

RESULTS

Among the five groups studied, nuclear PR expression was significantly elevated in glandular epithelial cells from tissue samples with histologic delay > or = 3 days consistent with luteal phase deficiency (LPD; group 1). Failure of PR down-regulation was associated with aberrant alpha v beta 3 integrin expression. Medical correction of LPD was associated with return of normal endometrial histology, normal integrin expression, and the loss of epithelial PR, similar to controls. The other two cycle-dependent integrin markers, alpha 1 beta 1 and alpha 4 beta 1, were not different between groups. In women with aberrant alpha v beta 3 and "in phase" endometrium, epithelial PR expression was not different from controls.

CONCLUSIONS

The establishment of normal endometrial receptivity appears to be tightly associated with the down-regulation of epithelial PR. Histologic delay, consistent with LPD, is associated with a failure of PR down-regulation and the lack of normal markers of endometrial receptivity. Occult uterine receptivity defects (aberrant beta 3 expression in otherwise normal histology) are regulated differently, suggesting alternate mechanisms also exist which influence endometrial receptivity.

The effect of oral contraceptive pills on markers of endometrial receptivity

OBJECTIVE

To determine if oral contraceptive (OC) usage alters expression of integrins associated with endometrial receptivity.

DESIGN

Immunohistochemical staining intensity for integrins was compared in frozen sections of endometrial tissue specimens obtained from women with normal ovulatory cycles (n = 23; cycle days 20 to 24 based on LH surge) and from those taking oral contraceptives pills (n = 23; cycle days 5 to 27).

SETTING

University-based outpatient infertility clinic.

RESULTS

Constitutive integrin expression in the endometrium (alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, alpha 6 beta 1, and alpha 6 beta 4) was similar in OC users and normally cycling individuals, except for an increase in epithelial alpha 3 beta 1 in OC users. Oral contraceptive use was associated with significant alterations in cycle-dependent integrin expression (alpha 1 beta 1, alpha 4 beta 1, and alpha v beta 3). Specifically, we observed increased glandular alpha 4 beta 1, and decreased alpha v beta 3 expression. The P-regulated alpha 1 subunit was present in both groups. Increased stromal alpha v and beta 3 and decreased alpha 3 beta 1 and alpha 6 beta 1 staining was observed in OC users.

CONCLUSIONS

Expression of those integrins most closely associated with endometrial receptivity, alpha v beta 3 and alpha 4 beta 1, is altered in the glandular epithelium of women taking OCs. Stromal integrin expression in OC users also differs from that in cycling women. These alterations in epithelial and stromal integrin expression suggest that impaired uterine receptivity is one mechanism whereby OCs exert their contraceptive actions.

Disruption of CD40-CD40 ligand interactions results in an enhanced susceptibility to Leishmania amazonensis infection

To study the role of CD40 ligand (CD40L) in the host immune responses against intracellular pathogens, we infected CD40L knockout (CD40L-/-) mice with Leishmania amazonensis. Although wild-type mice were susceptible to infection and developed progressive ulcerative lesions, tissue parasite burdens in CD40L-/- mice were significantly higher. This heightened susceptibility to infection was associated with an impaired T cell and macrophage activation and altered inflammatory response, as reflected by low levels of IFN gamma, lymphotoxin-tumor necrosis factor (LT-TNF), and nitric oxide (NO) production. Furthermore, CD40L-/- mice failed to generate a protective immune response after immunization. These results indicate an essential role of cognate CD40-CD40L interactions in the generation of cellular immune responses against an intracellular parasite.

[Enhancement of tumor growth after partial hepatectomy and blood transfusion]

Female adult BUF rats (6-8 week) received sham operation (Sham), 70% hepatectomy (PH); Sham or PH with blood transfusion (BT or PH+BT). BUF 7316A hepatoma cells were inoculated subcutaneously in the neck of rats on the operation day. Tumor size was measured from day 7 to 20 after inoculation. Sera and splenic adherent cells harvested on day 5 from Sham and PH rats were added into mixed lymphocyte cultures (MLR). The result showed that tumor growth in PH or BT rats was significantly promoted as compared to that in Sham rats (P < 0.01, P < 0.05). The most marked enhancement of tumor growth was observed in PH+BT rats (P < 0.001). Sera and splenic adherent cells from PH rat significantly inhibited MLR (P < 0.05). These results suggest that partial hepatectomy and blood transfusion are responsible for the enhancement of tumor growth. Some immunosupperassive factor might be produced in the process of liver regeneration, and blood transfusion might have an additive immunosuppressive effect.

Gene gun delivery of mRNA in situ results in efficient transgene expression and genetic immunization

The use of mRNA to transfer genetic information into mammalian somatic cells in vivo or ex vivo may be advantageous in a number of gene therapy protocols. Success in utilizing in vivo RNA delivery for transgene expression has been extremely limited, partially due to RNA instability and to the lack of an efficient intracellular delivery mechanism applicable to a wide variety of tissue or organ systems. We report here that a particle-mediated gene delivery technology can be used to effectively deliver RNA molecules into a number of mammalian somatic tissue types. Expression from RNA transcripts of three reporter genes, firefly luciferase, human growth hormone and human alpha-1 antitrypsin, was detected in monolayer and suspension cell cultures bombarded in vitro, and in in vivo bombarded rat liver tissues, and mouse liver and epidermal tissues. Gene gun treatment of mouse epidermis in vivo with human alpha-1 antitrypsin messenger RNA elicited a strong, consistent antibody response which showed an increased titer with subsequent boosts. Results from this study point to future opportunities of applying RNA delivery techniques for transgenic studies, genetic vaccination, and gene therapy.

Resonance Raman spectroscopic identification of a histidine ligand of b595 and the nature of the ligation of chlorin d in the fully reduced Escherichia coli cytochrome bd oxidase

Cytochrome bd oxidase is a bacterial terminal oxidase that contains three cofactors: a low-spin heme (b558), a high-spin heme (b595), and a chlorin d. The center of dioxygen reduction has been proposed to be a binuclear b595/d site, whereas b558 is mainly involved in transferring electrons from ubiquinol to the oxidase. Information on the nature of the axial ligands of the three heme centers has come from site-directed mutagenesis and spectroscopy, which have implicated a His/Met coordination for b558 (Spinner, F., Cheesman, M. R., Thomson, A. J., Kaysser, T., Gennis, R. B., Peng, Q., & Peterson, J. (1995) Biochem. J. 308, 641-644; Kaysser, T. M., Ghaim, J. B., Georgiou, C., & Gennis, R. B. (1995) Biochemistry 34, 13491-13501), but the ligands to b595 and d are not known with certainty. In this work, the three heme chromophores of the fully reduced cytochrome bd oxidase are studied individually by selective enhancement of their resonance Raman (rR) spectra at particular excitation wavelengths. The rR spectrum obtained with 413.1-nm excitation is dominated by the bands of the 5cHS b595(2+) cofactor. Excitation close to 560 nm yields a rR spectrum dominated by the 6cLS b558(2+) heme. Wavelengths between these values enhance contributions from both b595(2+) and b558(2+) chromophores. The rR bands of the ferrous chlorin become the major features with red laser excitation (595-650 nm). The rR data indicate that d2+ is a 5cHS system whose axial ligand is either a weakly coordinating protein donor or a water molecule. In the low-frequency region of the 441.6-nm spectrum, we assign a rR band at 225 cm-1 to the (b595)Fe(II)-N(His) stretching vibration, based on its 1.2-cm(-1) upshift in the 54Fe-labeled enzyme. This observation provides the first physical evidence that the proximal ligand of b595 is a histidine. Site-directed mutagenesis had suggested that His 19 is associated with either b595 or d (Fang, H., Lin, R. -J., & Gennis, R. B. (1989) J. Biol. Chem. 264, 8026-8032). On the basis of the present study, we propose that the proximal ligand of b595 is His 19. We have also studied the reaction of cyanide with the fully reduced cytochrome bd oxidase. In approximately 700-fold excess cyanide (approximately 35 mM), the 629-nm UV/vis band of d2+ is blue-shifted to 625 nm and diminished in intensity. However, the rR spectra at each of three different gamma(0) (413.1, 514.5, and 647.1 nm) are identical with or without cyanide, thus indicating that both b595 and d remain as 5cHS species in the presence of CN-. This observation leads to the proposal that a native ligand of ferrous chlorin d is replaced by CN- to form the 5cHS d2+ cyano adduct. These findings corroborate our companion study of the "as-isolated" enzyme in which we proposed a 5cHS d3+ cyano adduct (Sun, J., Osborne, J. P., Kahlow, M. A., Kaysser, T. M., Hill, J. J., Gennis, R. B., & Loehr, T. M. (1995) Biochemistry 34, 12144-12151). To further characterize the unusual and unexpected nature of these proposed high-spin cyanide adducts, we have obtained EPR spectral evidence that binding of cyanide to fully oxidized cytochrome bd oxidase perturbs a spin-state equilibrium in the chlorin d3+ to yield entirely the high-spin form of the cofactor.

Efficient extraction and partial purification of the polyribosome-associated stem-loop binding protein bound to the 3' end of histone mRNA

Replication-dependent histone mRNAs end in a highly conserved stem-loop sequence rather than a polyA sequence. A 45-kDa stem-loop binding protein (SLBP), which specifically binds the stem-loop of histone mRNA, is present in both polyribosomes and nuclei. An identical 45-kDa protein, as determined by partial protease digestion, is cross-linked to a 30 nt RNA containing the 3' stem-loop from both nuclei and polyribosomes. The SLBP can also be detected by a Northwestern blot procedure using the 30 nt RNA as a probe. As judged from the Northwestern assay, more than 90% of the SLBP in the cell is found in the polyribosomes with the remaining SLBP localized to the nucleus. Only 5-10% of the SLBP could be extracted from the polyribosomes with salt. Treatment of the polyribosomes with micrococcal nuclease prior to salt extraction solubilized 5-10 times more SLBP as an RNA-protein complex. The SLBP could be subsequently partially purified from this complex.

Heme oxygenase (HO-1): His-132 stabilizes a distal water ligand and assists catalysis

His-25 and His-132 are the primary candidates for the proximal heme iron ligand in heme oxygenase isozyme-1 (HO-1). The unambiguous spectroscopic demonstration that His-25 is the proximal iron ligand leaves the role of His-132 uncertain. Absorption and resonance Raman spectroscopy are used here to establish that mutation of His-132 to an alanine, glycine, or serine does not alter the histidine-iron bond, but results in the loss of the water molecule coordinated to the distal side of the iron in the wild-type enzyme-substrate complex. The His-132 mutations also (a) destabilize the ferrous-O2 complex with respect to autoxidation, which should result in partial uncoupling of NADPH consumption from heme oxidation, and (b) decrease the affinity of the enzyme for heme. The catalytic activity of the protein is decreased but not suppressed by these mutations: the H132G and H132A mutants retain 40-50% and the H132S mutant 20% of the activity of the wild-type protein. His-132, however, is required for catalytic turnover of the protein with H2O2. These results place His-132 close to the iron on the distal side of the heme pocket and indicate that His-132 facilitates, but is not absolutely required for, the catalytic turnover of HO-1.

Identification of the epitope for monoclonal antibody 4B1 which uncouples lactose and proton translocation in the lactose permease of Escherichia coli

Monoclonal antibody 4B1 binds to a conformational epitope on the periplasmic surface of the lactose permease of Escherichia coli, uncoupling lactose and H+ translocation in a manner indicating that it blocks deprotonation [Carrasco, N., Viitanen, P., Herzlinger, D., & Kaback, H. R. (1984) Biochemistry 23, 3681; Herzlinger, D., Viitanen, P., Carrasco, N., & Kaback, H. R. (1984) Biochemistry 23, 3688]. In this paper, 4B1 binding to purified lactose permease is shown to exhibit a KD of about 5 x 10(-10) M by surface plasmon resonance. Furthermore, the combined use of mutants containing 6 contiguous His residues in each periplasmic loop in the permease and Cys-scanning mutagenesis in conjunction with chemical labeling demonstrates that 4B1 binds specifically to the periplasmic loop between helices VII and VIII and that Phe247 and Gly254 are the primary determinants. Remarkably, although 4B1 binding uncouples lactose and H+ translocation, none of the amino acid residues in periplasmic loops, particularly Phe247 or Gly254, play an important role in the transport mechanism. Moreover, binding of avidin to biotinylated Glu255-->Cys in the loop containing the epitope has no effect on transport activity. Therefore, the uncoupling effect of 4B1 involves highly specific interactions which in all likelihood exert a torsional effect on the loop, resulting in a conformational change in helix VII and/or VIII that alters the pKas of residues involved in lactose-coupled H+ translocation.

Early computation of shape and reflectance in the visual system

A compelling sense of three-dimensional shape may be conveyed by the photograph of an object. Cues such as contour, shading, perspective and occlusion, to name a few, contribute to this percept. Psychophysical experiments suggest that certain aspects of three-dimensional shape are computed rapidly and in parallel by the visual system. Here we report that reflectance is also computed rapidly; moreover, it is the apparent reflectance, rather than brightness or perceptual three-dimensional shape, that is the primary basis for discrimination during the early stages of visual processing.

[The ultrastructure of the Eustachian tube]

To observe the ultrastructure of mucous membrane of Eustachian tube in human being, ninteen human's Eustachian tube from various ages, were divided into tympanic segment, isthmus and pharyngeal segment and observed under SEM. The results showed that the epithelium of Eustachian tube consisted of ciliated cells, nonciliated cells and goblet cells. At the isthmus, the bone and cartilage junction, the cells got crowded, and there were more and more goblet cells from tympanic side to pharyngeal side, as well as the cilia of ciliated cell leaned towards the pharyngeal side. The upper one third part of Eustachian tube was covered mostly by nonciliated cells, the floor and lower parts were ciliated cells. It was concluded that the upper parts of Eustachian tube's wall played an important role in maintaining equation of pressure in middle ear, and the floor and lower parts in providing an active mucociliary mechnism. The defence system of the Eustachian tube mucous membrane had developed during the fetal stage and was well established at birth.

Quantitative analysis of glomeruli lesions in patients with mesangial proliferative glomerulonephritis

By using computer imaging analysis system combined with light microscopy, the glomeruli lesions on biopsy specimens sections were quantitatively analysed. The pathological changes of mesangial proliferative glomerulonephritis (MsPGN) in children were quantitatively evaluated and the correlation between the mesangial matrix area (MA) and some clinical data were also analysed. The results indicated that the levels of various glomerular parameters in MsPGN group were higher than those of normal controls. No correlation was found between MA and 24 h urinary protein excretion, but a negative correlation was revealed between MA and estimated GFR. MA was also correlated with the duration of MsPGN recovery. It was suggested that the quantitative analysis of glomerular parameters by computer is a reproducible methods. The parameter of MA may be used for evaluation of the renal function, determination of the duration of therapy and evaluation of prognosis of MsPGN in children.

Endarterectomy for calcified porcelain aorta associated with aortic valve stenosis

BACKGROUND

A calcified porcelain aorta may complicate aortic valve insertion and require an alternative, more complex method for valve replacement. The reason for this is that sutures cannot be inserted through the calcific plates in the annulus and ascending aorta.

METHODS

In 6 patients with an average age of 73.8 years (range, 65 to 81 years), we performed the simpler procedure of aortic endarterectomy of the calcific plates with the aortic valve replacement. We realized that there may be an increased risk of postoperative complications, particularly stroke. The calcific plates were fractured to allow debridement of the calcium. In addition, an end-arterectomy was performed of the left main coronary ostium in 2 patients, and 5 patients also had coronary artery bypass grafting performed.

RESULTS

All 6 patients underwent successful operations without major complications. On follow-up, echocardiography or computed tomographic scans in 3 patients have not shown dilation of the ascending aorta.

CONCLUSION

Endarterectomy of the aorta may be an option in the management of patients with calcification of the aorta.

Efficient and sustained transgene expression in mature rat oligodendrocytes in primary culture

In order to evaluate the characteristics and efficiency of gene transfer in primary cultures of oligodendrocytes, four different techniques including particle bombardment (Accell gene gun), cationic liposome-mediated transfection (lipofection), calcium phosphate co-precipitation and retroviral infection were compared using the LacZ and luciferase reporter genes. Highly purified postnatal adult rat oligodendrocytes were obtained by sequential immunopanning, plated in culture, and transfected using various reporter and promoter genes. The most efficient expression of LacZ and luciferase genes was found with particle mediated gene delivery. The transgene expression level obtained with gene gun delivery was at least two- to 100-fold greater than three other tested gene transfer methods. Comparison of the relative strength of four viral and two cellular promoters in these primary oligodendrocytes cultures demonstrated that the CMV promoter was the strongest. Using a human growth hormone (hGH) reporter gene, a long-term transgene expression pattern in primary oligodendrocytes was demonstrated to be sustained in culture for the entire experimental period (4 weeks) after particle-mediated gene transfer. These results demonstrate that expression of a foreign gene can be effectively achieved in primary cultures of adult oligodendrocytes, especially by using the particle bombardment method. The results also suggest that the current ex vivo gene transfer system may be used to manipulate oligodendrocytes for future application in gene therapy studies.

[Late bladder complications following radiotherapy of carcinoma of the uterine cervix]

OBJECTIVE

To analyse the causes, clinical features, treatment and prevention of late bladder complications following radiotherapy of carcinoma of the uterine cervix.

METHOD

This clinical retrospective study included 378 cases of irradiation cystitis following radiotherapy for carcinoma of the uterine cervix from February, 1958 to October, 1987.

RESULTS

The incidence of irradiation cystitis was 3.2% and was not related to age, FIGO staging and the methods of intracavitary irradiation (conventional or afterloading). It was related to the external appearance of the local lesion; 66.5% of the tumors of patients with late bladder complications was of the exophytic type prior to radiotherapy. 51.1% of the patients developed late bladder complications in a period of 2-5 years after radiotherapy; 16.7% in 5-10 years and only 3.4% within the first years. The patients with irradiation cystitis had received a 10% higher dosage than that routine delivered, as found either in intracavitary irradiation of 39.4% of patients or in external irradiation of 31.6% of patients. Based on the clinical features and cystoscopic findings, late bladder complications can be divided into three types: (1) sudden and temporary hematuria (35.7%); (2) persistent hematuria (63.2%); and (3) vesico-vaginal fistula (1.1%). The 5-year survival rate of patients with irradiation cystitis was 90.4% which was higher than the survival rates of all patients treated by conventional intracavitary irradiation (65.7%) and all patients treated by afterloading intracavitary irradiation (70.4%). 3.7% of patients died of late bladder complications.

CONCLUSIONS

To decrease the occurrence of late bladder complications and to obtain long term survival: (1) Dosage to the bladder should be adequate, and over dose to the bladder should by all means be avoided; (2) Patients are to be taught to observe indicated personal care during radiotherapy as well as in the follow-up period; (3) Early institution of proper conservative treatment of cystitis is beneficial.

The effects of out-of-plane rotations on two dimensional portal image registration in conformal radiotherapy of the prostate

PURPOSE

Rotations of the patient out of the image plane can significantly degrade the accuracy of two-dimensional (2D) image registration. This study determines the magnitude of the geometric errors introduced by 2D image registration as a result of out-of-plane rotations, and analyzes the dosimetric effects of these errors.

METHODS AND MATERIALS

The magnitude of the errors introduced by 2D registration were determined by comparing orthogonal view portal images of a rotated phantom to simulator reference images of the same phantom without rotation. Dosimetric effects were calculated for three-dimensional (3D) conformal prostate treatments by applying the registration errors to patient treatment plans. The calculations were performed using a modified version of the dose calculation software used in our Cancer Center for 3D treatment planning based on computed tomography (CT). A method to detect out-of-plane rotations, specific to pelvic treatments, is introduced that uses the relative displacement of the centers of gravity of the acetabula in lateral images.

RESULTS

The inherent uncertainty in the registration algorithm was 0.6 +/- 0.5 mm in translation and 0.7 +/- 0.8 degree in rotation within the image plane. For a 2 degrees out-of-plane rotation, the errors increase to 2.3 +/- 1.0 mm and 1.2 +/- 1.1 degrees. In some clinically realizable treatment scenarios it was observed that the errors introduced by the registration procedure could result in an overdosing of the rectal wall. The method to detect out-of-plane rotations was found to have an accuracy of better than 1 degree for rotations of less than 10 degrees.

CONCLUSIONS

The errors introduced to the patient position by 2D image registration have dosimetrically significant consequences for out-of-plane rotations of 2 degrees or more. However, when used in conjunction with the method to detect out-of-plane rotations, 2D registration software was found to cause insignificant dose errors and, thus, become a more reliable and accurate clinical tool.