Perinatal myocardial infarction in a newborn with a structurally normal heart

Myocardial infarction in a newborn infant in the absence of congenital heart disease and anomalous coronary artery anatomy is extremely rare. We report a case of a newborn with a structurally normal heart who presented shortly after birth with congestive heart failure and cardiovascular collapse suggestive of a hypoplastic left ventricle or critical aortic stenosis. This newborn had a massive myocardial infarction caused by thromboembolic occlusion of the left main coronary artery. Clinical, laboratory, and autopsy data suggest the event occurred in utero.

Selective reporter expression in mast cells using a chymase promoter

Primate alpha-chymases are mast cell neutral proteases that are involved in regulating several regulatory peptides including angiotensin II. Because of significant substrate specificity differences among the chymase group of enzymes, animal models that overexpress primate chymases are crucial for delineating the in vivo function of these enzymes. Activation of alpha-prochymase requires processing enzymes and proteoglycans found in mast cell secretory granules. Thus, the development of models overexpressing active primate chymase requires a mast cell-specific promoter. We show that the 571-base pair (bp) 5'-upstream sequence of the baboon chymase gene, which encodes an alpha-chymase, coupled to the prokaryotic lacZ gene allows the targeting of beta-galactosidase to mast cells in transgenic mice. Tissue expression of the transgene is similar to the expression of the endogenous mouse alpha-chymase mouse mast cell protease-5. A mouse mast cell line that endogenously expresses mouse mast cell protease-5 (JKras mast cells) also selectively supports the expression of this transgene. In vitro transcription studies in JKras mast cells shows the critical role of a GATA cis-regulatory motif in baboon chymase promoter, located approximately 430-bp upstream of the transcription start site. These results suggest that the 571-bp domain of the baboon chymase promoter contains most, if not all, of the mast cell-specific region of the promoter. We describe here for the first time a promoter that directs expression of transgenes specifically to mouse mast cells. This promoter should be generally applicable for dominant expression of mast cell regulatory proteins.

Distinct multisite synergistic interactions determine substrate specificities of human chymase and rat chymase-1 for angiotensin II formation and degradation

Human chymase and rat chymase-1 are mast cell serine proteases involved in angiotensin II (Ang II) formation and degradation, respectively. Previous studies indicate that both these enzymes have similar P1 and P2 preferences, which are the major determinants of specificity. Surprisingly, despite the occurrence of optimal P2 and P1 residues at the Phe8 downward arrow and Tyr4 downward arrow bonds (where downward arrow, indicates the scissile bond in peptide substrates) in Ang I (DRVYIHPFHL), human chymase cleaves the Phe8 downward arrow bond with an approximately 750-fold higher catalytic efficiency (kcat/Km) than the Tyr4 downward arrow bond in Ang II (DRVYIHPF), whereas rat chymase-1 cleaves the Tyr4 downward arrow bond with an approximately 20-fold higher catalytic efficiency than the Phe8 downward arrow bond. Differences in the acyl groups IHPF and DRVY at the Phe8 downward arrow and Tyr4 downward arrow bonds, respectively, are chiefly responsible for the preference of human chymase for the Phe8 downward arrow bond. We show that the IHPF sequence forms an optimal acyl group, primarily through synergistic interactions between neighboring acyl group residues. In contrast to human chymase, rat chymase-1 shows a preference for the Tyr4 downward arrow bond, mainly because of a catalytically productive interaction between the enzyme and the P'1 Ile5. The overall effect of this P'1 Ile interaction on catalytic efficiency, however, is influenced by the structure of the acyl group and that of the other leaving group residues. For human chymase, the P'1 Ile interaction is not productive. Thus, specificity for Ang II formation versus Ang II degradation by these chymases is produced through synergistic interactions between acyl or leaving group residues as well as between the acyl and leaving groups. These observations indicate that nonadditive interactions between the extended substrate binding site of human chymase or rat chymase-1 and the substrate are best explained if the entire binding site is taken as an entity rather than as a collection of distinct subsites.

Association of antral mucosal levels of interleukin 8 and reactive oxygen radicals in patients infected with Helicobacter pylori

1. Helicobacter pylori infection is characterized by an infiltration of neutrophils in the gastric mucosa. Neutrophil activation is an important source of reactive oxygen radicals, which cause tissue damage. Studies have shown that in Helicobacter pylori-infected patients there is increased mucosal production of interleukin 8. However, the role of interleukin 8 in the Helicobacter pylori-related inflammatory process and its relationship with reactive oxygen radicals remains to be clarified. The aims of this study were to investigate if there is any association between antral mucosal levels of interleukin 8 and reactive oxygen radicals and their relationship to gastric antral inflammation. 2. Fifty-two patients referred for endoscopy were recruited into the study. Gastric antral biopsies were taken for histology, culture and measurement of interleukin 8 and chemiluminescence (measuring reactive oxygen radicals). Interleukin 8 was measured by ELISA and the result expressed as pg/mg biopsy. Luminol-enhanced chemiluminescence was measured as mV min-1 mg-1 biopsy. Antral inflammation was assessed by a pathologist in a blinded fashion. 3. Antral mucosal levels of interleukin 8 and reactive oxygen radicals were significantly higher in Helicobacter pylori-colonized mucosa than in Helicobacter pylori-negative mucosa. After the eradication of Helicobacter pylori in patients with duodenal ulcer the median values (ranges) of interleukin 8 and reactive oxygen radicals fell from 1.21 (0.10-2.40) to 0.65 (0.00-1.60) and from 110.0 (10.0-959.0) to 14.5 (0.0-85.0) respectively. There was a positive correlation between interleukin 8 concentration and chemiluminescence response in the antral mucosa (r = 0.72). A higher interleukin 8 concentration was associated with greater neutrophil infiltration (r = 0.72) and mononuclear cell infiltration (r = 0.55); the magnitude of the chemiluminescence response was also positively associated with neutrophil (r = 0.77) and mononuclear cell infiltration (r = 0.59). 4. Interleukin 8 concentration is associated with an infiltration of neutrophils and mononuclear cells and is correlated with the production of reactive oxygen radicals in antral gastric mucosa infected with Helicobacter pylori. These findings suggest that interleukin 8 may be important in attracting and activating phagocytes to release reactive oxygen radicals, thereby causing mucosal damage.

The active state of the AT1 angiotensin receptor is generated by angiotensin II induction

In the current model of receptor activation, the given hormone is not involved in the conversion of the inactive receptor (R) to the fully active state (R*). Rather, it preferentially selects the activated receptor conformation, thereby shifting the equilibrium toward R*. The hormone angiotensin II (Ang II) contains two residues, Tyr4 and Phe8, that are essential for agonism. We show that the conserved Asn111 in transmembrane helix III of the AT1 angiotensin receptor directly interacts with the Tyr4 side chain. A decrease in the size of the Asn111 side chain induces an intermediate activated receptor conformation (R'). The Ang II analogue [Sar1,Ile4,Ile8]Ang II fully activates the N111G mutant, indicating that either the transition from R' to R* or the stabilization of the R* state requires binding by Ang II but not its Tyr4 and Phe8 side chains. In contrast, [Sar1,Ile4,Ile8]Ang II binds to but does not activate the wild-type AT1 receptor (R), suggesting that in the wild-type receptor spontaneous occurrence of R' and R* states is rare. Thus, Ang II through interactions involving Tyr4 and Phe8 induces a transition from R to R' and through unspecified interactions induces transition from R' to R* states rather than stabilizing the spontaneously generated R* state by "conformational, selection".

Removal of intramedullary nails from the femur: a review of 45 cases

The excellent biocompatibility of titanium and its alloys may result in osseointegration. In order to determine if this presents an obstacle to removal of intramedullary nails, we retrospectively reviewed a series of 45 cases of isolated removal of a femoral nail. Indications for removal were persistent pain and discomfort, request of an asymptomatic patient, or skeletal immaturity. Twenty-three nails were titanium, and 22 were stainless steel. Although removal of the titanium nails had a significantly longer operative time (110 vs. 84 min), analysis of variance indicated that this was due to a greater number of crosslocking screws in the titanium nails (2.2 vs. 0.6) and a tendency to set the titanium nails deeper in the femur. The use of the titanium material per se did not pose a risk factor for difficulty in late removal of an intramedullary nail.

Placental pathologic conditions in anticardiolipin antibody positive women whose infants had congenital heart defects

Anticardiolipin antibodies (ACLA) are present in 10% of women with recurrent pregnancy loss. Other associations with ACLA are arterial and venous thrombosis, cerebral infarction, pulmonary hypertension, preterm delivery, and fetal growth retardation. A previous prospective study of infants of mothers with positive ACLA identified an increased incidence of congenital heart disease in this population. As a follow-up, the placentas of the initial 40 ACLA-positive patients were studied to determine whether there was an increased incidence of infarct or thrombosis compared with that in control subjects matched for maternal age and gestational age within the same 2-year period. The age of ACLA-positive mothers was 30 +/- 5 years versus 29 +/- 5 years in the ACLA-negative mothers. Gestational age was 37 +/- 2 weeks in both groups; placental weight was 553 +/- 169 gm in the ACLA-positive group versus 593 +/- 117 gm in the ACLA-negative group. The birth weight was 2972 +/- 709 gm in infants of ACLA-positive mothers and 2920 +/- 674 gm in infants of ACLA-negative mothers. There was no statistically significant difference between the two groups in gestational age, maternal disease, placental histologic findings, placental weight, type of delivery, or type of ACLA. Twenty-seven ACLA-positive women were receiving prednisone. Chi square analysis showed the ACLA-positive mothers to have more spontaneous abortions (p = 0.02) and to have more children with congenital heart disease (5 ventricular septal defects and 2 atrial septal defects) (p = 0.006). In summary, infants born with congenital heart defects in women positive for ACLA did not have significant placental pathologic conditions when compared with control infants.

The practice of surgical staging and its impact on adjuvant treatment recommendations in patients with stage I endometrial carcinoma

A survey of American gynecologic oncologists was undertaken to assess their compliance with current surgical staging criteria in patients with early endometrial carcinoma. One hundred forty-four members of the Society of Gynecologic Oncologists responded to the survey. Respondents treated an average of 22 new cases annually. Tumor grade and intraoperative determination of depth of myometrial invasion were demonstrated to influence the frequency of lymphatic dissection. In grade 1, 2, and 3 lesions, 76, 60, and 34% of responders, respectively, indicated that depth of invasion influenced their decision to perform lymphadenectomy. In addition, depth of invasion was important in determining type and extent of lymphatic resection. Further, the impact of pathologic lymph node status on postoperative adjuvant radiation therapy recommendations was evaluated for various stratifications of endometrial adenocarcinoma confined to the corpus. The greatest differences in treatment recommendations were noted in the 50-66% invasion category. For grade 1 and 2 cancers, adjuvant therapy recommendations were reduced by 23 and 16% respectively when comparing pelvic and combined therapy versus none and vaginal therapy. The effect of surgical staging data on clinical decisions is clearly evident. The knowledge of pathologically negative lymph node status reduces the recommendation for postoperative adjuvant radiotherapy in patients with adenocarcinoma otherwise confined to the uterine corpus.

Angiotensin II-forming activity in a reconstructed ancestral chymase

The current model of serine protease diversity theorizes that the earliest protease molecules were simple digestive enzymes that gained complex regulatory functions and restricted substrate specificities through evolution. Among the chymase group of serine proteases are enzymes that convert angiotensin I to angiotensin II, as well as others that simply degrade angiotensins. An ancestral chymase reconstructed with the use of phylogenetic inference, total gene synthesis, and protein expression had efficient and specific angiotensin II-forming activity (turnover number, about 700 per second). Thus, angiotensin II-forming activity is the more primitive state for chymases, and the loss of such activity occurred later in the evolution of some of these serine proteases.

Molecular determinants of peptide and non-peptide binding to the AT1 receptor

1. Several residues critically involved in AT1 receptor ligand-binding and activation have now been identified based on mutational and biochemical studies. 2. Asp281 and Lys199 of the rat AT1 receptor ion-pair with Arg2 and the Phe3 alpha-COOH of angiotensin II (AngII), respectively, and the Asp281/Arg2 interaction is critical for full agonist activity. 3. Agonist activity of AngII also requires an interaction of the Phe8 side chain with His256, which is achieved by docking of the alpha-COOH with Lys199. Non-peptide agonists interact with Lys199 and His256 in a similar fashion. 4. The crucial acid pharmacophores of AngII and the non-peptide antagonist, losartan, appear to occupy the same space within the receptor pocket. Binding of the tetrazole anion moiety of losartan involves multiple contacts, such as Lys199 and His256. However, this interaction does not involve a conventional salt bridge, but rather an unusual lysine-aromatic interaction. 5. Asp1 of AngII forms an ion-pair with His183, which stabilizes the receptor-bound conformation of AngII but is not critical for receptor activation. 6. These interactions and the involvement of other residues in stabilizing the wild-type receptor conformation or in receptor/G-protein coupling are considered here. 7. Despite these insights, considerable effort is still needed to elucidate how ligand binding induces receptor activation, what determines the specificity of AT1 receptor coupling to multiple G-proteins and the in vivo role of receptor down-regulation.

Long-term outcome following curative surgery for malignant large bowel obstruction

This study determined whether the long-term outcome of patients with obstructing colorectal cancer could be related to conventional pathological prognostic variables or to other clinical, operative or histological features. Ninety-eight patients with bowel obstruction who had undergone potentially curative surgery and survived the postoperative period were studied. Features related to poor long-term outcome after a median follow-up of 5 years included bowel perforation at initial operation (P = 0.007), advanced tumour stage (P < 0.001), poor tumour differentiation (P = 0.02), mucin production by tumour (P = 0.004) and the presence of vascular (P = 0.08) and neural (P = 0.004) invasion. Outcome was not significantly related to the seniority of the operating surgeon (P = 0.52), even when this was adjusted for potentially confounding variables (adjusted hazard rate ratio for trainee surgeons 1.4 (95 per cent confidence interval 0.9-2.4), P = 0.16). Conventional prognostic features may help to identify the majority of patients with obstructed colorectal cancer at high risk of tumour recurrence and death.

Aspergillus and lung transplantation

BACKGROUND

Aspergillus infection is a known complication of transplantation.

METHODS

We describe our experience with 37 patients who received lung transplants over 2 years at Loyola University Medical Center. All patients who had evidence of aspergillus on culture of clinical specimens or had biopsies with hyphal forms consistent with aspergillus were categorized according to the clinical manifestations. Important risk factors were analyzed in comparison with other lung transplant recipients during the same period.

RESULTS

The incidence of invasive aspergillosis was high (16%). No patient with disseminated disease survived. Locally invasive disease responded well to treatment with amphotericin B and itraconazole.

CONCLUSIONS

Lung transplantation patients may have a higher incidence of aspergillosis as compared with other transplantation groups. Prophylactic measures need to be explored.

The chymase-angiotensin system in humans: biochemistry, molecular biology and potential role in cardiovascular diseases

Angiotensin I-converting enzyme (ACE) inhibitors are highly effective in the treatment of cardiovascular diseases. However, the relationship among the antihypertensive effects of ACE inhibitors, ACE inhibition and plasma angiotensin II levels is complex. During chronic therapy with ACE inhibition, plasma angiotensin II levels return to normal despite a continued antihypertensive effect. Recent studies show that a conversion of angiotensin I to angiotensin II in tissues can proceed despite complete ACE inhibition. In the search for a potential ACE inhibitor-resistant angiotensin II-forming enzyme activity in human heart tissue, chymase was identified as a major angiotensin II-forming enzyme. In primates, chymase-like angiotensin II-forming activity is localized in a number of tissues including the heart, blood vessels and lungs. Within the human heart, mast cells and endothelial cells are the sites of synthesis and storage of chymase, but a high level of the secreted chymase is also found in the cardiac interstitium, associated with the extracellular matrix. Mammalian chymases may be divided into two distinct structural groups, alpha and beta. alpha-chymases, such as human chymase, are highly specific and efficient angiotensin II-forming enzymes. beta-chymases, including several rat and mouse chymases, have a broad substrate specificity like chymotrypsin and do not form angiotensin II. In humans and baboons only a single chm gene of the alpha-subtype can be identified. By using an angiotensin I analogue that is selectively converted to angiotensin II by chymase and not ACE, a functional chymase-dependent angiotensin II formation has recently been demonstrated in conscious baboons.(ABSTRACT TRUNCATED AT 250 WORDS)

The docking of Arg2 of angiotensin II with Asp281 of AT1 receptor is essential for full agonism

The structural model of AT1 angiotensin receptor contains seven-transmembrane alpha-helices with three interhelical loops on either side of the membrane. The angiotensin II binding pocket within the receptor is not clearly defined. We showed earlier that Lys199 in transmembrane-helix-5 of the AT1 receptor binds the COOH-terminal alpha-carboxyl group of angiotensin II (Noda, K., Saad, Y., Kinoshita, A., Boyle, T. P., Graham, R. M., Husain, A., and Karnik, S. S. (1995) J. Biol. Chem. 270, 2284-2289). We now show that His183 and Asp281, both located in the extracellular domain of the AT1 receptor, are involved in binding the NH2-terminal Asp1 and Arg2 residues of angiotensin II, respectively. The Asp1/His183 interaction appears to be weak and is unlikely to be important for agonism. But the loss of Arg2/Asp281 interaction leads to partial agonism of the receptor. The action of non-peptide agonists is not affected by Asp281 mutations. These results suggest that several independent interactions between angiotensin II and AT1 receptor are necessary for full agonism. Since L-162,313 the non-peptide agonist of the AT1 receptor is a partial agonist that does not make contact with Asp281, we speculate that the degree of agonism may be increased if it is redesigned to make contacts with Asp281.

Prevalence of mitral valve prolapse in Saudi sickle cell disease patients in Dammam - A prospective-controlled echocardiographic study

Mitral valve prolapse (MVP) is the most common valvular heart disease and there are numerous reports of a strong association with many conditions including sickle cell disease (SCD). Since SCD is very common in the Eastern Province of Saudi Arabia, we undertook a prospective controlled study to determine and compare the prevalence of MVP in the SCD patients with other groups of subjects. Three hundred and sixteen subjects (156 males and 160 females) were studied. They were divided into four groups based on their hematologic diagnoses - I SCD, II normal controls, III sickle cell traits, IV other anemias. The prevalence of MVP is 17.4% in Group I, 13.3% in Group II, 21.4% in Group III and 19.4% in Group IV. There was no statistically significant difference in the prevalence of MVP among the four study groups. In contrast to a previous study, these results show that the prevalence of MVP by echocardiographic criteria (M-mode and 2-dimensional) in SCD patients is the same as in the general population. We believe that mere case-reporting and lack of or inappropriate control in most of the clinical series are responsible for the wide range of conditions claimed to be associated with MVP.

Effects of angiotensin II generated by an angiotensin converting enzyme-independent pathway on left ventricular performance in the conscious baboon

Human chymase is a serine proteinase that converts angiotensin (Ang) I to Ang II independent of angiotensin converting enzyme (ACE) in vitro. The effects of chymase on systemic hemodynamics and left ventricular function in vivo were studied in nine conscious baboons instrumented with a LV micromanometer and LV minor axis and wall thickness sonomicrometer crystal pairs. Measurements were made at baseline and after [Pro11DAla12] Ang I, a specific substrate for human chymase, was given in consecutive fashion as a 0.1 mg bolus, an hour-long intravenous infusion of 5 mg, a 3 mg bolus, and after 5 mg of an Ang II receptor antagonist. [Pro11DAla12]Ang I significantly increased LV systolic and diastolic pressure, LV end-diastolic and end systolic dimensions and the time constant of LV relaxation and significantly decreased LV fractional shortening and wall thickening. Administration of a specific Ang II receptor antagonist reversed all the hemodynamic changes. In separate studies, similar results were obtained in six of the baboons with ACE blockade (20 mg, intravenous captopril). Post-mortem studies indicated that chymase-like activity was widely distributed in multiple tissues. Thus, in primates, Ang I is converted into Ang II by an enzyme with chymase-like activity. This study provides the first in vivo evidence of an ACE-independent pathway for Ang II production.

Tetrazole and carboxylate groups of angiotensin receptor antagonists bind to the same subsite by different mechanisms

To identify specific interactions between either the tetrazole or carboxylate pharmacophores of non-peptide antagonists and the rat AT1 receptor, 6 basic residues were examined by site-directed mutagenesis. Three of the mutants (H183Q, H256Q, and H272Q) appeared to be like wild type. Lys102 and Arg167 mutants displayed reduced binding of the non-peptide antagonist losartan. Examination of their properties employing group-specific angiotensin II analogues indicated that their effects on binding were indirect. Interestingly, the affinity of losartan was not altered by a K199Q mutation, but the same mutation reduced the affinity of angiotensin II, the antagonist [Sar1,Ile8]angiotensin II, and several carboxylate analogues of losartan. An Ala199 substitution reduced the affinity of peptide analogues to a larger extent as compared to the affinity of losartan. Thus, the crucial acidic pharmacophores of angiotensin and losartan appear to occupy the same space within the receptor pocket, but the protonated amino group of Lys199 is not essential for binding the tetrazole anion. The binding of the tetrazole moiety with the AT1 receptor involves multiple contacts with residues such as Lys199 and His256 that constitute the same subsite of the ligand binding pocket. However, this interaction does not involve a conventional salt bridge, but rather an unusual lysine-aromatic interaction.

Human prochymase activation. A novel role for heparin in zymogen processing

Human prochymase is packaged with heparin in mast cell granules and appears to be activated by dipeptidylpeptidase I. We show that a high affinity interaction between heparin and prochymase allows the 2-residue propeptide to be cleaved by dipeptidylpeptidase I. A conserved Glu in the propeptide is necessary for this heparin effect. Following propeptide cleavage, capture of the newly generated NH2 terminus by an "activation groove" on the enzyme activates the enzyme and concurrently prevents a progressive degradation of the NH2 terminus by dipeptidylpeptidase I. Surrogate peptide studies show that the activation groove is unoccupied in prochymase and is specific for the chymase NH2 terminus. These observations indicate that heparin is an important cofactor in the prochymase activation process and explain how dipeptidylpeptidase I, a nonspecific processing enzyme, can effect a specific cleavage of the zymogen propeptide.

Evaluation of a yoga based regimen for treatment of osteoarthritis of the hands

OBJECTIVE

Yoga and relaxation techniques have traditionally been used by nonmedical practitioners to help alleviate musculoskeletal symptoms. The objective of this study was to collect controlled observations of the effect of yoga on the hands of patients with osteoarthritis (OA).

METHODS

Patients with OA of the hands were randomly assigned to receive either the yoga program or no therapy. Yoga techniques were supervised by one instructor once/week for 8 weeks. Variables assessed were pain, strength, motion, joint circumference, tenderness, and hand function using the Stanford Hand Assessment questionnaire.

RESULTS

The yoga treated group improved significantly more than the control group in pain during activity, tenderness and finger range of motion. Other trends also favored the yoga program.

CONCLUSION

This yoga derived program was effective in providing relief in hand OA. Further studies are needed to compare this with other treatments and to examine longterm effects.

Gh: a GTP-binding protein with transglutaminase activity and receptor signaling function

The alpha 1-adrenergic receptors activate a phospholipase C enzyme by coupling to members of the large molecular size (approximately 74 to 80 kilodaltons) G alpha h family of guanosine triphosphate (GTP)-binding proteins. Rat liver G alpha h is now shown to be a tissue transglutaminase type II (TGase II). The transglutaminase activity of rat liver TGase II expressed in COS-1 cells was inhibited by the nonhydrolyzable GTP analog guanosine 5'-O-(3-thiotriphosphate) or by alpha 1-adrenergic receptor activation. Rat liver TGase II also mediated alpha 1-adrenergic receptor stimulation of phospholipase C activity. Thus, G alpha h represents a new class of GTP-binding proteins that participate in receptor signaling and may be a component of a complex regulatory network in which receptor-stimulated GTP binding switches the function of G alpha h from transglutamination to receptor signaling.