Sex differences in the management and long-term outcome of acute myocardial infarction. A statewide study. MIDAS Study Group. Myocardial Infarction Data Acquisition System

BACKGROUND

We wished to evaluate whether differences in the rate of invasive cardiac procedures between men and women with acute myocardial infarction are associated with different short- and long-term mortality.

METHODS AND RESULTS

The database (Myocardial Infarction Data Acquisition System, MIDAS) included all discharges for the years 1986 and 1987 with the diagnosis of acute myocardial infarction in New Jersey, based on the New Jersey hospital discharge data system (MIDS/UB-82). Accuracy of the data was evaluated by auditing 726 randomly selected charts. The variables examined included age, sex, race, comorbidity (anemia, chronic liver disease, cancer, chronic obstructive pulmonary disease, diabetes, hypertension, prior myocardial infarction), complications (left ventricular dysfunction, arrhythmias, conduction defects), insurance status, performance of cardiac catheterization, percutaneous transluminal coronary angioplasty, or coronary artery bypass graft surgery, and survival up to 3 years. Women were older, had longer hospital stay, and were more likely than men to have anemia, diabetes, hypertension, left ventricular dysfunction, and Medicare or Medicaid insurance coverage. They were less likely than men to be admitted to a hospital equipped to perform invasive procedures or to have chronic obstructive pulmonary disease, chronic liver disease, prior myocardial infarction, or arrhythmias. After adjustment for these differences, women were less likely than men to have cardiac catheterization. Cardiac catheterization was associated with lower mortality. Women up to age 70 had higher 3-year death rates than men after adjustment for age, race, comorbidity, complications, and insurance type. This difference between men and women was somewhat diminished after the performance of cardiac catheterization and revascularization was taken into account. Unadjusted mortality was high in this study group.

CONCLUSIONS

Women with acute myocardial infarction are less likely to have invasive cardiac procedures and have higher 3-year adjusted death rate up to age 70 than men.

Fetal fibroblast contraction of collagen matrices in vitro: the effects of epidermal growth factor and transforming growth factor-beta

Wound contraction is an important component of healing but, in the extreme, may lead to excessive scar formation and pathological wound contracture. Fetal rabbit wounds heal without contraction or scarring, whereas excisional fetal sheep wounds have been shown to contract, but no scarring or pathological wound contracture is noted. We used an in vitro model, the fibroblast-populated collagen lattice, to study the ability of fetal fibroblasts to coordinate contraction of a collagen matrix and the modulating effects of epidermal growth factor and transforming growth factor-beta 1 on this contraction. With increasing gestational age, fibroblasts increased the degree of collagen lattice contraction. Epidermal growth factor inhibited contraction by fetal fibroblasts, whereas transforming growth factor-beta 1 stimulated it. These findings suggest that while intrinsic differences between fetal and adult fibroblasts exist, polypeptide growth factors may operate at the site of tissue repair to alter cell phenotype. Further work is underway to delineate the role of soluble protein factors responsible for the absence of scarring and contracture seen in the fetal wound.

Insulin activates a novel adipocyte mitogen-activated protein kinase kinase kinase that shows rapid phasic kinetics and is distinct from c-Raf

Treatment of adipocytes with insulin or phorbol 12-myristate 13-acetate (PMA) results in transient activation of mitogen-activated protein kinase kinase (MEK) (Tmax = 90 s) and mitogen-activated protein kinase (MAPK) (Tmax = 300 s). We have identified a novel insulin-stimulated MEK kinase (I-MEKK) in the 100,000 x g infranatant that shows rapid phasic kinetics that temporally precede that of MEK. Maximal activation of I-MEKK occurs within 20 +/- 5 s (S.D., n = 3) followed by complete inactivation by 30 +/- 10 s (S.D., n = 3). I-MEKK was characterized by anion-exchange and gel filtration chromatography and separated into two distinct activities of approximately 56 kDa that phosphorylated and activated MEK. I-MEKKs did not co-elute on anion exchange with c-Raf or 73-kDa MEK kinase (MEKK), suggesting they are distinct enzymes. Protein phosphatase 2A inactivated both I-MEKKs in vitro and in the intact cell okadaic acid blocked inactivation in the presence of insulin. These results suggest activation of I-MEKK involves phosphorylation on serine or threonine residues. I-MEKK was not activated by PMA, suggesting that in adipocytes the enzyme represents a divergence point between signal transduction pathways mediated by insulin and those activating protein kinase C.

Breast capsule contracture: is fibroblast activity associated with severity?

Factors responsible for breast capsule contracture remain elusive. Using an in vitro model of wound contraction, the fibroblast-populated collagen lattice (FPCL), breast capsule fibroblasts and control dermal fibroblasts from ten patients were analyzed. Comparison was made to determine (1) if the activity of dermal fibroblasts on a collagen lattice correlated with the activity of breast capsule fibroblasts or if capsular fibroblasts are unique, and (2) if the degree of fibroblast-driven collagen contraction correlated with clinical severity of breast capsule contracture. If so, a preoperative predictor of breast capsule contracture would be available. Dermal fibroblasts and breast capsule fibroblasts were cultured and mixed with media and collagen to form a matrix, and then the degree of lattice contraction was measured. A correlation between breast capsule fibroblasts and control dermal fibroblasts with respect to collagen matrix contraction was confirmed. Collagen lattice contraction coordinated by fibroblasts derived from breast capsules did not correlate with clinical severity of capsular contracture. These results indicate that the degree of breast capsule contracture can not be predicted by fibroblast activity alone. An interaction between inflammatory cells, extracellular matrix, and fibroblasts is hypothesized. Further work is needed to delineate the mechanisms responsible for breast capsule contracture.

Gamma-phosphate-linked ATP-sepharose for the affinity purification of protein kinases. Rapid purification to homogeneity of skeletal muscle mitogen-activated protein kinase kinase

Recently, Sowadski and colleagues [Knighton, D.R., Zheng, J., Eyck, L.F.T., Ashford, V.A., Xuong, N., Taylor, S.S. & Sowadski, J.M. (1991) Science 407, 407-420] reported the structure of a ternary complex of the catalytic subunit of cAMP-dependent protein kinase (cyclic A kinase), MgATP and a 20-residue inhibitor peptide, at a resolution of 0.27 nm. This structure has since been refined to 0.2-nm resolution and the orientation of the nucleotide and interactions of MgATP with numerous conserved residues at the active site defined [Zheng, J., Knighton, D.R., Eyck, L.F.T., Karlsson, R., Xuong, N., Taylor, S.S. & Sowadski, J.M. (1993) Biochemistry, in the press]. These studies revealed that the adenosine portion of ATP is buried deep within the catalytic cleft, with the alpha, beta and gamma phosphates protruding towards the opening of the cleft. The unique spatial positioning of MgATP within the catalytic cleft of cyclic A kinase and its interactions with conserved amino acids found in all protein kinases, led us to reconsider the use of ATP as an affinity ligand for the purification of these enzymes. In this paper, we describe a straightforward method for the synthesis of [gamma-32P]adenosine-5'-(gamma-4-aminophenyl)triphosphate for the covalent linkage of ATP to Sepharose through its gamma phosphate. In the presence of 20 microM ATP, adenosine-5'-(gamma-4-aminophenyl)triphosphate exhibited apparent Ki values of 103.6, 75.18, 176.28 and 120.00 microM against cyclic A kinase, mitogen-activated protein kinase (p42mapk), mitogen-activated protein kinase kinase and p60c-src, respectively. To illustrate the effectiveness of adenosine-5'-(gamma-4-aminophenyl)triphosphate-Sepharose as an affinity column for protein kinases, we have used the resin to purify rabbit skeletal muscle mitogen-activated protein kinase kinase over 19000-fold to homogeneity.

Functional expression of a MAP kinase kinase in COS cells and recognition by an anti-STE7/byr1 antibody

Mitogen-activated protein (MAP) kinases p42mapk and p44mapk are activated by dual tyrosine and threonine phosphorylation in vivo. Both MAPKs are phosphorylated and activated in vitro by an activator recently identified as a protein-tyrosine/threonine kinase. We have isolated a putative cDNA for a MAP kinase kinase (MAPKK) and determined its structure [Proc. Natl. Acad. Sci. USA, in press]. The protein encoded by this cDNA shares sequence homology with two yeast protein kinases byr1 and STE7. We now report that stimulation with serum of COS cells expressing this shares sequence homology with two yeast protein kinases byr1 and STE7. We now report that stimulation with serum of COS cells expressing this protein amplifies MAPK activator activity markedly. The increased activity co-migrates during chromatography with the expressed 45 kDa protein, recognized by an anti-STE7/byr1 antibody, and is abrogated by treatment with phosphatase 2A. Thus, this cDNA encodes a functional MAPKK. The anti-STE7/byr1 antibody also recognized a 46 kDa COS cell protein that was resolved from the expressed MAPKK by anion-exchange chromatography. This immunoreactive protein co-eluted with endogenous MAPKK activity, suggesting identification of the immunoreactive band as monkey MAPKK.

Accelerated improvement of alcoholic liver disease with enteral nutrition

This prospective study compared the effects of tube-fed nutrition with those of a regular diet in alcoholic liver disease. The high prevalence of malnutrition in patients with alcoholic liver disease requires clarification of the benefits of aggressive nutritional support. Patients were randomly assigned a regular diet without or with tube-fed supplementation, delivering 1.5 g/kg protein and 167 kJ/kg daily. Comparisons of encephalopathy, antipyrine clearance, metabolic rate, and biochemical parameters were performed weekly for 4 weeks. Sixteen patients receiving enteral supplementation had antipyrine half-life (50% vs. 3% reduction), serum bilirubin (25% vs. 0% reduction), and median encephalopathy scores that improved more rapidly than those of controls. Initially, 15 controls did not consume adequate calories to meet measured resting energy expenditure. Aggressive nutritional intervention accelerated improvement in alcoholic liver disease. Adverse effects did not offset the demonstrated benefits of a 2-cal/mL, casein-based tube-fed supplement. These findings support the use of standard, casein-based solutions in the treatment of alcoholic liver disease and as the control condition for future studies.

Comparison of anti-fetal colonic microvillus and anti-CEA antibodies in peroperative radioimmunolocalisation of colorectal cancer

Local recurrence of colorectal cancer may result from failure to assess accurately the extent of tumour at operation. It has been suggested that peroperative radioimmunolocalisation may improve this assessment. The degree to which this is possible has been studied using a hand-held gamma detecting probe and comparing two 125I-labelled monoclonal antibodies to colorectal tumours. The antibodies were to fetal colonic microvillus membrane (FM1D10) and to carcinoembryonic antigen (A5B7). Sixty-nine per cent (9/13) of the FM1D10 and 98% (43/44) of A5B7 labelled tumours took up significant amounts of antibody with a tumour to normal colon ratio of more than 1.5:1. The uptake was significantly better for A5B7 with a median tumour to normal colon ratio of 3.3 (1.1-13.8) compared to 1.85 (0.75-7.7) for FM1D10 (P less than 0.001). The tumour: colon ratio of both antibodies was independent of the serum CEA, Dukes' stage or the degree of histological differentiation. There was a linear correlation for tumour to normal colon ratios between the gamma detecting probe and the same tissue examined in a conventional well counter (correlation coefficient r = 0.78, P less than 0.001). Colorectal tumours demonstrate a rapid and reliable uptake of anti-CEA monoclonal antibody A5B7. This antibody can be detected with a peroperative gamma detecting probe and has the potential to improve the surgeon's appreciation of the extent of tumour and therefore may influence the surgery performed. Detailed clinical studies are now being carried out.

A dominant negative mutation in two proteins created by ectopic expression of an AU-rich 3' untranslated region

We have found that the ectopic expression of a specific gene's 3' untranslated region leads to the dose dependent loss, relative to gene copy number, of that specific mRNA and protein, as well as an associated protein, in a eukaryotic cell line. The loss of these proteins from the eukaryotic cell line also results in specific phenotypic changes in these cells, suggesting that we have created a dominant negative mutant. This gene's 3' untranslated region is known to contain numerous AU sequences, reminiscent of other eukaryotic genes whose expression may be regulated by these sequences. The apparent control of gene expression by a truncated 3' untranslated region sequence provides further evidence supporting the regulatory function of these regions. The resulting decrease in steady-state mRNA levels by the overexpression of a portion of that gene's 3' untranslated region further suggests the possible existence of a factor(s) that may bind to this region, and thus regulate gene function via its mRNA. The use of a gene's 3' untranslated sequence to create a specific dominant negative mutation may also be applicable to other eukaryotic genes whose expression is controlled by similar regulatory sequences.

Differential regulation of actin and myosin isoenzyme synthesis in functionally overloaded skeletal muscle

Overload hypertrophy of the chicken anterior latissimus dorsi muscle is accompanied by a replacement of one myosin isoenzyme (slow myosin-1, SM1) by another (slow myosin-2, SM2). To investigate the molecular mechanisms by which these changes occur, we measured the fractional synthesis rates (ks) in vivo of individual myosin-heavy-chain isoenzymes, total actin and total protein during the first 72 h of muscle growth. Although the ks of total protein and actin were doubled at 24 h, the ks for SM1 and SM2 were depressed. However, the ks of both isomyosins were nearly tripled by 72 h. Despite the increase in muscle size observed at 72 h, the amount of SM1 was reduced by half, indicating increased degradation of SM1. Results of translation of polyribosomes in vitro paralleled the results obtained in vivo. The proportion of total polyadenylylated mRNA in total RNA was increased at 48 and 72 h, but unchanged at 24 h despite the increase in protein synthesis at 24 h. Nuclease-protection analyses indicate that the level of specific SM1 and SM2 mRNAs change in a reciprocal fashion during overload. We conclude that gene-specific and temporal differences exist in the regulatory mechanisms that control overload-induced muscle growth.

Regulation of myosin heavy-chain gene expression during skeletal-muscle hypertrophy

Changes in the myosin phenotype of differentiated muscle are a prominent feature of the adaptation of the tissue to a variety of physiological stimuli. In the present study the molecular basis of changes in the proportion of myosin isoenzymes in rat skeletal muscle which occur during compensatory hypertrophy caused by the combined removal of synergist muscles and spontaneous running exercise was investigated. The relative amounts of sarcomeric myosin heavy (MHC)- and light (MLC)-chain mRNAs in the plantaris (fast) and soleus (slow) muscles from rats was assessed with cDNA probes specific for different MHC and MLC genes. Changes in the proportion of specific MHC mRNA levels were in the same direction as, and of similar magnitude to, changes in the proportion of myosin isoenzymes encoded for by the mRNAs. No significant changes in the proportion of MLC proteins or mRNA were detected. However, high levels of MLC3 mRNA were measured in both normal and hypertrophied soleus muscles which contained only trace amounts of MLC3 protein. Small amounts of embryonic and neonatal MHC mRNAs were induced in both muscles during hypertrophy. We conclude that the change in the pattern of myosin isoenzymes during skeletal-muscle adaptation to work overload is a consequence of changes in specific MHC mRNA levels.

Inhibition of metastatic potential by fucosidase: an NMR study identifies a cell surface metastasis marker

NMR spectroscopy is able to detect subtle changes to the surface chemistry of cells. We have previously shown that high-resolution 1H NMR methods can identify tumor cells with the capacity to metastasize, and we now report that the long T2 relaxation value (500-800 ms) observed in metastatic rat mammary adenocarcinoma cells is removed by treatment with fucosidase. Two-dimensional scalar-correlated NMR (COSY) spectra of fucosidase-treated cells show that a cross peak, consistent with scalar coupling between the methyl and methine groups on fucose and usually associated with malignancy and metastatic ability, is absent. Metastases were observed in only two out of ten rats injected subcutaneously with enzyme-treated cells compared to eight out of ten with untreated cells. NMR studies on isolated cellular lipids identified the long T2 relaxation value only in the ganglioside fraction. This fraction accounts for 51% of the total 14C-labelled fucose incorporated into the cells. We propose that fucogangliosides are an indicator of metastatic potential in rats. The observation that a cell surface metastasis marker has an NMR signal with a characteristically long relaxation value has important consequences for the future use of magnetic resonance imaging and spectroscopy in the cancer clinic.

Features of squamous and adenocarcinoma in the same cell in a xenografted human transitional cell carcinoma: evidence of a common histogenesis?

Ultrastructural features of squamous differentiation have been found in adenocarcinomatous cells in a xenografted line (UCRU-BL-17) established in nude mice from a primary human bladder transitional cell carcinoma (grade III, stage T4) with a tetraploid DNA component. The line has been characterized by light and electron microscopy, flow cytometry and immunocytochemistry. The initial xenograft showed predominantly adenocarcinomatous differentiation with mucin secretion, whilst the subsequent passages also contained cells showing squamous differentiation. A xenograft subline established from a cell culture of the initial xenograft shows the emergence of a population of cells with near triploid DNA, which are less differentiated, grow more quickly, show decreased expression of carcinoembryonic antigen, and a change in the distribution of staining with peanut lectin from cell surface to cytoplasm. These lines offer an unusual opportunity to study the histogenetic relationships between the histological subtypes of bladder cancer.

Fractional synthesis rates in vivo of skeletal-muscle myosin isoenzymes

The synthesis rates of different myosin isoenzymes in a single muscle, and of the same isoenzymes in different muscles (soleus, masseter and plantaris), were measured. The rate of total protein synthesis was significantly higher in the soleus [greater than 95% slow myosin (SM)] than in the plantaris [greater than 95% fast myosin (FM)]. Two fast isoenzymes, FM2 and FM3, were synthesized at different rates in the masseter, and SM was synthesized at a faster rate than FM. Intermediate myosin had a synthesis rate similar to that of FM. There was a small but significant difference between the synthesis rates of the SM isoenzymes of the soleus and masseter muscles. FM3 was synthesized faster in the masseter than in the plantaris, whereas FM2 was synthesized faster in the plantaris than in the masseter.

The differential protection by WR2721 of skin versus growing cartilage following irradiation in weanling rats

The potential for radioprotection of growing cartilage by the thiophosphate WR2721 was evaluated in weanling rats using single fractions of irradiation. Protection of acute skin toxicity was monitored simultaneously. Single doses of 600, 1200, 1800, or 2400 cGy were administered to the left tibia of CrL:CD(SD)BR female rats in groups of 12. Identically treated groups were injected with 310 mg/kg WR2721 (2/3 the determined LD50/30) in a concentration of 26 mg/ml intraperitoneally 15 min prior to irradiation. Rats untreated or given WR2721 without radiation served as control groups. Radiographs of the irradiated and unirradiated tibiae for each animal were obtained weekly to the date of sacrifice at 80 days following the initial treatment. Skin toxicity was assessed weekly starting on the second week using Moulder's scale (J.E. Moulder, J.J. Fischer, and A. Casey, Radiology 115, 465-470 (1975]. No significant difference in bone growth as measured by tibial lengths for the WR2721-treated or untreated animals was observed. Skin toxicity including moist desquamation occurred in irradiated limbs and was substantially less in rats treated with WR2721. As opposed to previous work with cysteamine, WR2721 as administered had no significant radioprotective effect on tibial growth in weanling rats but substantially reduced the accompanying skin toxicity.

Xenografted small cell undifferentiated cancer of prostate: possible common origin with prostatic adenocarcinoma

The first xenograft line of small cell undifferentiated carcinoma of the prostate (UCRU-PR-2) has been established and characterized. The donor tumor and the xenograft share the common morphological and ultrastructural features of small cell undifferentiated carcinoma (including neurosecretory granules) but also elaborate epithelial membrane antigen and carcinoembryonic antigen, in addition to neurone-specific enolase. The line expresses a diploid DNA complement. Androgen and estrogen receptors are not expressed, although prostatic acid phosphatase is present in sera from tumor-bearing mice in low levels. From these studies, we postulate a possible common stem cell origin for adenocarcinoma and small cell undifferentiated carcinoma of the prostate; further studies of a cell line derived from this tumor may clarify the issue.

Motilin secretion and the migrating myoelectric complex in the pig

The concentration of motilin in plasma from the abdominal aorta and the hepatic portal vein and the net portal motilin output varied with the phase of the migrating myoelectric complex (m.m.c.) in five of six pigs fasted for 17 h. Maximum concentrations and output occurred 9-12 min before phase III in the duodenum or upper jejunum. In fed pigs m.m.c.s occurred and the first phase III in the duodenum occurred within 90 min of feeding. Both portal and arterial motilin concentrations were reduced after feeding and no longer varied with the phase of the m.m.c. Altered secretion of motilin after feeding did not appear to be associated with absorption of glucose as infusion of glucose (50 g/l, 10 ml/min) into the duodenum raised arterial and portal plasma glucose concentrations to post-prandial levels yet motilin concentrations and output rates still varied with the phase of the m.m.c. Infusions of motilin (1 or 10 ng/kg X min) into the portal vein of 17 h fasted pigs did not induce an extra phase III or alter the duration of the m.m.c. Hydrochloric acid (100 mmol/l) infused into the duodenum of fasted pigs at 10-21 ml/min increased the concentration of motilin in the portal blood but was without effect at 5 ml/min. Rapid injections of 50 ml hydrochloric acid into the duodenum also increased the portal motilin concentration. Hydrochloric acid infusion or injection did not alter the interval between phase IIIs. It is concluded that motilin secretion is a consequence of the m.m.c. or shows the same periodicity as the m.m.c. but that motilin is not an important factor in the initiation and control of the m.m.c. in the pig.

Changes in skeletal-muscle myosin isoenzymes with hypertrophy and exercise

The patterns of myosin isoenzymes in fast- and slow-twitch muscles of the rat hindlimb were studied, by pyrophosphate/polyacrylamide-gel electrophoresis, with hypertrophy (induced by synergist removal) and with spontaneous running exercise of 4 and 11 weeks duration. At 11 weeks, changes with hypertrophy in the slow-twitch soleus, composed of greater than 95% SM2 (slow myosin 2) in normal muscles, were minor, and consisted of an increase in the SM1 and SM1', and a loss of intermediate myosin (IM), an isoenzyme characteristic of Type IIa fibres [Fitzsimons & Hoh (1983) J. Physiol. (London) 343, 539-550]. The changes were dramatic, however, in the fast-twitch plantaris muscle. There was a 3-fold increase in the proportion of SM. In addition, IM became the predominant isoenzyme in the profile of hypertrophied plantaris by 4 weeks. These increases were balanced by decreases in the proportion of FM2 (fast myosin 2), with FM1 completely absent from the profile at 11 weeks. The changes in the plantaris with exercise were similar in direction but not as extensive as those with hypertrophy, and FM1 remained present at control levels throughout the study. When hypertrophy and exercise were combined, the increase in slow myosin was equal to the sum of the increases with each treatment alone. Changes at 4 weeks were intermediate between those of control and 11-week muscles. Peptide mapping of individual myosin isoenzymes showed that the heavy chains of IM were different from either fast or slow heavy chains. Furthermore, IM was found to be composed of a mixture of fast and slow light chains. These changes suggest that a transformation of myosin from fast to slow isoforms was in progress in the plantaris in response to hypertrophy, via a Type-IIa-myosin (IM) intermediate stage, a phenomenon similar to that occurring in chronically stimulated fast muscles during fast-to-slow transformation [Brown, Salmons & Whalen (1983) J. Biol. Chem. 258, 14686-14692].