Essential role of HIV type 1-infected and cyclooxygenase 2-activated macrophages and T cells in HIV type 1 myocarditis

HIV-1 cardiomyopathy has become a major cause of death in AIDS patients, but its pathogenesis is unclear. We used an antigen retrieval technique and immunostaining to investigate the hearts of 15 AIDS patients, of whom 3 had dilated cardiomyopathy. Immunocytochemistry shows infiltration of the left ventricular myocardium with mononuclear cells, ranging from minimal to diagnostic of myocarditis. The infiltrates include macrophages and CD3(+) and CD8(+) T cells. The tight junction protein ZO-1 is disrupted at the site of monocyte-macrophage vascular penetration and the coronary vessels show fibrinogen leakage in the hearts of AIDS patients, but not in the normal heart. A subset of infiltrating macrophages is doubly positive for cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase. HIV-1 peptides gp120 and Nef are expressed in macrophages and T cells, but not in cardiomyocytes. COX-2 is expressed by both gp120-positive and gp120-negative macrophages. The hearts of AIDS patients separate into those showing minimal infiltrates with low COX-2 expression and those with dense infiltrates and high COX-2; all failing hearts are in the latter group. These data suggest that COX-2-activated and HIV-1-infected monocyte-macrophages and T cells play a crucial role in the progression of HIV-1 myocarditis to HIV-1 cardiomyopathy.

Leukocytes infiltrating the pancreatic islets of nonobese diabetic mice are transformed into inactive exiles by combinational anti-cell adhesion therapy

Leukocytes infiltrate the pancreatic islets of nonobese diabetic mice, causing beta-cell destruction and autoimmune Type I diabetes. Here, we completely blocked adoptive transfer of diabetes and reduced spontaneous disease incidence from 71% to 17% by simultaneously administering a combination of antibodies directed against alpha4, beta2, and beta7 integrins and their ligands VCAM-1, MAdCAM-1, and ICAM-1 for 52 and 28 days, respectively. CD4 and CD8 T cells and macrophages were excluded from islets and remained entrapped in a peri-islet location as inactive exiles, no longer expressing normal levels of interferon-gamma, interleukin-4, and iNOS. Only IL-10 expression was retained, which could aid immunosuppression. Infiltrating leukocytes retained a peri-islet location, even 215 days following suspension of antibody treatment, potentially forming a barrier to the entry of active, autoantigen-reactive T cells. Combination treatment was effective against spontaneous disease when administered from 7 days of age but ineffective when initiated late in the prediabetic period (day 40 or 70). Nevertheless, anti-alpha4 subunit mAb monotherapy alone was very effective, reducing insulitis to levels similar to those obtained with combinational antibody treatment, suggesting that alpha4 integrins are major receptors contributing to leukocyte infiltration. Treatment with anti-alpha4 integrin antibody retained some therapeutic benefit when administered from days 7, 40, or 70 of age. The results have implications for the treatment of diabetes and provide a unique insight into the fate of disease-forming leukocytes following anti-CAM therapy.

Gorlin syndrome. A case report

Gorlin's syndrome is a genetic disorder of autosomal dominant inheritance with high penetrance and variable expression. It embraces a constellation of many organs principally affects the skin, skeleton, and endocrine and nervous system. A rare case is reported to illustrate the features of Gorlin's syndrome without the features of basal cell carcinoma and to emphasize the need for early recognition and careful follow up by the dentist prevent severe sequelae.

Characterization of Wnt gene expression in developing and postnatal hair follicles and identification of Wnt5a as a target of Sonic hedgehog in hair follicle morphogenesis

Mutations in WNT effector genes perturb hair follicle morphogenesis, suggesting key roles for WNT proteins in this process. We show that expression of Wnts 10b and 10a is upregulated in placodes at the onset of follicle morphogenesis and in postnatal hair follicles beginning a new cycle of hair growth. The expression of additional Wnt genes is observed in follicles at later stages of differentiation. Among these, we find that Wnt5a is expressed in the developing dermal condensate of wild type but not Sonic hedgehog (Shh)-null embryos, indicating that Wnt5a is a target of SHH in hair follicle morphogenesis. These results identify candidates for several key follicular signals and suggest that WNT and SHH signaling pathways interact to regulate hair follicle morphogenesis.

Skeletal muscle Na currents in mice heterozygous for Six5 deficiency

Myotonic dystrophy results from a trinucleotide repeat expansion between the myotonic dystrophy protein kinase gene (Dmpk), which encodes a serine-threonine protein kinase, and the Six5 gene, which encodes a homeodomain protein. The disease is characterized by late bursts of skeletal muscle Na channel openings, and this is recapitulated in Dmpk -/- and Dmpk +/- murine skeletal muscle. To test whether deficiency of the nearby Six5 gene also affected Na channel gating in murine skeletal muscle, we measured Na currents from cell-attached patches in Six5 +/- mice and age-matched wild-type and Dmpk +/- mice. Late bursts of Na channel activity were defined as an opening probability >10% measured from 10 to 110 ms after depolarization. There was no significant difference in the occurrence of late Na channel bursts in wild-type and Six5 +/- muscle, whereas in Dmpk +/- muscle there was greater than fivefold increase in late bursts (P < 0.001). Compared with wild-type mice, Na current amplitude was unchanged in Six5 +/- muscle, whereas in Dmpk +/- muscle it was 36% reduced (P < 0.05). Thus, since Six5 +/- mice do not exhibit the Na channel gating abnormality of Dmpk deficiency, we conclude that Six5 deficiency does not contribute to the Na channel gating abnormality seen in dystrophia myotonica patients.

Overexpression of Smad2 reveals its concerted action with Smad4 in regulating TGF-beta-mediated epidermal homeostasis

Members of the transforming growth factor-beta (TGF-beta) superfamily are critical regulators for epithelial growth and can alter the differentiation of keratinocytes. Transduction of TGF-beta signaling depends on the phosphorylation and activation of Smad proteins by heteromeric complexes of ligand-specific type I and II receptors. To understand the function of TGF-beta and activin-specific Smad, we generated transgenic mice that overexpress Smad2 in epidermis under the control of keratin 14 promoter. Overexpression of Smad2 increases endogenous Smad4 and TGF-beta 1 expression while heterozygous loss of Smad2 reduces their expression levels, suggesting a concerted action of Smad2 and -4 in regulating TGF-beta signaling during skin development. These transgenic mice have delayed hair growth, underdeveloped ears, and shorter tails. In their skin, there is severe thickening of the epidermis with disorganized epidermal architecture, indistinguishable basement membrane, and dermal fibrosis. These abnormal phenotypes are due to increased proliferation of the basal epidermal cells and abnormalities in the program of keratinocyte differentiation. The ectodermally derived enamel structure is also abnormal. Collectively, our study presents the first in vivo evidence that, by providing an auto-feedback in TGF-beta signaling, Smad2 plays a pivotal role in regulating TGF-beta-mediated epidermal homeostasis.

Dysregulation of the adipoinsular axis -- a mechanism for the pathogenesis of hyperleptinemia and adipogenic diabetes induced by fetal programming

Obesity and its related disorders are the most prevalent health problems in the Western world. Using the paradigm of fetal programming we developed a rodent model which displays the phenotype of obesity and metabolic disorders commonly observed in human populations. We apply maternal undernutrition throughout gestation, generating a nutrient-deprived intrauterine environment to induce fetal programming. Maternal undernutrition results in fetal growth retardation and in significantly decreased body weight at birth. Programmed offspring develop hyperphagia, obesity, hypertension, hyperleptinemia and hyperinsulinism during adult life and postnatal hypercaloric nutrition amplifies the metabolic abnormalities induced by fetal programming. The adipoinsular axis has been proposed as a primary candidate for linking the status of body fat mass to the function of the pancreatic beta-cells. We therefore investigated the relationship between circulating plasma concentrations of leptin and insulin and immunoreactivity in the endocrine pancreas for leptin and leptin receptor (OB-R) in genetically normal rats that were programmed to become obese during adult life. Virgin Wistar rats were time mated and randomly assigned to receive food either available ad libitum (AD group) or at 30% of the ad libitum available intake (UN group). Offspring from UN mothers were significantly smaller at birth than AD offspring (AD 6.13+/-0.04 g, UN 4.02+/-0.03 g, P<0.001). At weaning, offspring were assigned to one of two diets (a standard control diet or a hypercaloric diet consisting of 30% fat) for the remainder of the study. At the time of death (125 days of age), UN offspring had elevated (P<0.005) fasting plasma insulin (AD control 1.417+/-0.15 ng/ml, UN control 2.493+/-0.33 ng/ml, AD hypercaloric 1.70+/-0.17 ng/ml, UN hypercaloric 2.608+/-0.41 ng/ml) and leptin (AD control 8.8+/-1.6 ng/ml, UN control 14.32+/-1.9 ng/ml, AD hypercaloric 15.11+/-1.8 ng/ml, UN hypercaloric 30.18+/-5.3 ng/ml) concentrations, which were further increased (P<0.05) by postnatal hypercaloric nutrition. The elevated plasma insulin and leptin concentrations were paralleled by increased immunolabeling for leptin in the peripheral cells of the pancreatic islets. Dual immunofluorescence histochemistry for somatostatin and leptin revealed that leptin was co-localized in the pancreatic delta-cells. OB-R immunoreactivity was evenly distributed throughout the pancreatic islets and was not changed by programming nor hypercaloric nutrition. Our data suggest that reduced substrate supply during fetal development can trigger permanent dysregulation of the adipoinsular feedback system leading to hyperleptinemia, hyperinsulinism and compensatory leptin production by pancreatic delta-cells in a further attempt to reduce insulin hypersecretion in the progression to adipogenic diabetes.

Long-term follow-up on use of pericardial graft in the surgical management of Peyronie's disease

We have previously reported on the use of Tutoplast cadaveric pericardium as an alternative material for grafting the tunica albugineal defect after Peyronie's plaque excision with satisfactory results in 11 patients. We now review long-term outcomes in this cohort of men. Eleven patients with significant penile curvature interfering with sexual intercourse were evaluated after at least 12 months of conservative therapy. All patients underwent pre-operative evaluation, including penile duplex Doppler ultrasound studies. Chemically processed and gamma-irradiated pericardium (Biodynamics International, Parsippany, NJ) was used to graft the cavernosal defect after surgical excision of the penile plaque. Three patients simultaneously underwent placement of penile prostheses secondary to documented erection problems identified at duplex Doppler ultrasound evaluation. The long-term postoperative complications and erectile function were evaluated with a mean follow-up of 30 months (range 25-35 months). All patients reported resolution of penile curvature allowing for normal sexual function after a mean follow-up of the first 14 months. Thirty months after placement of cadaveric pericardium, the three prosthetic patients still reported excellent sexual function. For the eight patients who did not undergo placement of a prosthesis, three with small to medium plaque size (<2 x 5 cm) continued to do well. The remaining five patients with a large plaque size (>2 x 5 cm) did well initially, but later reported difficulty maintaining erection due to venous leakage, thus they are currently using either a vacuum constriction device or an Actis ring. Three out of these five venous leakage patients had ventral plaques; two had dorsal plaques, one of significant size (4 x 5 cm). We conclude that for those patients who do not undergo placement of a prosthesis, a better long-term outcome is observed when the plaque is small to medium in size (<2 x 5 cm) and dorsally located. Patients with ventral plaque, extreme curvature, or plaque size >4 x 5 cm were more likely to have venoocclusive dysfunction, necessitating further intervention.

Immunoexpression of interleukin-1beta in pancreatic islets of NOD mice during cyclophosphamide-accelerated diabetes: co-localization in macrophages and endocrine cells and its attenuation with oral nicotinamide

During insulin-dependent diabetes mellitus, islet invading immune cells destroy beta cells over a prolonged asymptomatic pre-diabetic period. Cytokines synthesised and secreted by specific immune cells within the islet infiltrate may be crucial effectors of beta cell destruction or protection during the disease. Interleukin-1beta may be a key cytokine which may act in concert with other cytokines in initiating and/or promoting beta cell destruction. We have examined this hypothesis in NOD mice by assessing the intra-islet expression and co-localization of interleukin-1beta at different time-points following cyclophosphamide administration. We have also tested the effects of long-term oral nicotinamide given to NOD mice in suppressing intra-islet expression of the cytokine in this accelerated model. Cyclophosphamide was administered to day 95 female NOD mice. Pancreatic tissues were examined by dual-label confocal immunofluorescence microscopy for the expression and co-localization of interleukin-1beta at days 0, 4, 7, 11 and at onset of diabetes (day 14). Diabetes developed in 7/11 mice 14 days after administration of cyclophosphamide while nicotinamide completely prevented the disease. At day 0, interleukin-1beta immunolabelling was observed in selective intra-islet macrophages, several somatostatin cells and in a few beta cells. However, at day 4, it was seen mostly in somatostatin and some beta cells. At day 7, an increasing number of interleukin-1beta cells were observed within the islets and co-localized to several somatostatin cells, beta cells and macrophages. The mean number of intra-islet interleukin-1beta cells reached a peak at day 11 and was significantly higher than at day 7 (p = 0.05) and at day 14 (onset of diabetes; p = 0.03). At day 11, interleukin-1beta immunolabelling was also present in selective macrophages which co-expressed inducible nitric oxide synthase. At onset of diabetes, some macrophages, residual beta cells and somatostatin cells showed immunolabelling for the cytokine. Exposure of NOD mice to oral nicotinamide was associated with a considerably reduced expression of interleukin-1beta cells within the islet at day 11 (p = 0.002). We conclude that cylophosphamide treatment enhances the expression of interleukin-1beta in selective macrophages, somatostatin and beta cells during the course of the disease. Its expression reaches a maximum immediately prior to onset of diabetes. Interleukin-1beta present in intra-islet macrophages, somatostatin and beta cells may influence its expression by autocrine and paracrine means. Interleukin-1beta expression within islet macrophages may also up-regulate inducible nitric oxide synthase within the same macrophage or adjacent macrophage populations. These intra-islet molecular events may corroborate with other local cytotoxic processes leading to beta cell destruction. Oral nicotinamide may attenuate intra-islet expression of interleukin-1beta and thus inducible nitric oxide synthase during prevention of Type 1 diabetes in this animal model. The expression of interleukin-1beta in specific islet endocrine cell-types shown in this study requires further investigation.

Mitogen-activated protein kinase phosphatase 1 activity is necessary for oxidized phospholipids to induce monocyte chemotactic activity in human aortic endothelial cells

Entrapment and oxidation of low density lipoproteins (LDL) in the sub-endothelial space is a key process in the initiation of atherosclerotic lesion development. Functional changes induced by oxidized lipids in endothelial cells are early events in the pathogenesis of atherosclerosis. Oxidized-l-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (ox-PAPC), a major component of minimally modified/oxidized-LDL (MM-LDL) mimics the biological activities assigned to MM-LDL both in vitro in a co-culture model as well as in vivo in mice. We hypothesized that ox-PAPC initiates gene expression changes in endothelial cells that result in enhanced endothelial/monocyte interactions. To analyze the gene expression changes that oxidized lipids induce in endothelial cells, we used a suppression subtractive hybridization procedure to compare mRNA from PAPC-treated human aortic endothelial cells (HAEC) with that of ox-PAPC-treated cells. We report here the identification of a gene, mitogen-activated protein kinase phosphatase 1 (MKP-1), that is rapidly and transiently induced in ox-PAPC-treated HAEC. Inhibition of MKP-1 using either the phosphatase inhibitor sodium orthovanadate or antisense oligonucleotides prevents the accumulation of monocyte chemotactic activity in ox-PAPC-treated HAEC supernatants. Furthermore, we show that decreased monocyte chemotactic activity in HAEC treated with sodium orthovanadate or MKP-1 antisense oligonucleotides is due to decreased MCP-1 protein. Our results implicate a direct role for MKP-1 in ox-PAPC-induced signaling pathways that result in the production of MCP-1 protein by ox-PAPC-treated HAEC.

Automated discrimination between atrial fibrillation and atrial flutter in the resting 12-lead electrocardiogram

Computerized time-domain analysis of the QRST-subtracted 12-lead electrocardiogram (ECG) has been used successfully to determine several atrial activity patterns. These time-domain methods are particularly useful for low-frequency signals such as those originating at the sinus node. However, high frequency atrial fibrillation (AFIB) and atrial flutter (AFL) waves can be better estimated by using spectral methods. In this study, we investigated the use of spectral entropy (SE) and spectral peak detection to distinguish fibrillatory from flutter activity in the QRST-subtracted ECG. In a set of 4,172 cardiologist-overread ECGs, a computerized ECG analysis program (12SL MAC-Rhythm, GE-Marquette Medical Systems, Milwaukee, WI) detected 270 AFIB rhythms and 100 AFL rhythms. Compared to the cardiologist's reading, the AFIB versus AFL miss-classification error was 5.6%. The Fourier Transform was used to estimate the power spectral density of the QRST-subtracted ECG data. Individual lead spectra were then averaged and SE was computed for each of the ECGs originally called AFIB or AFL by the computer program. Additional criteria that included SE, spectral peak frequencies, and time-domain measures of atrial activity were then applied to discriminate between the 2 rhythms. Employing these criteria resulted in a decrease of miss-classification error to 2.5%.

Rapid detection of anti-Helicobacter pylori IgG in urine using immunochromatography

BACKGROUND

Non-invasive methods to detect the presence of H. pylori infection continue to be refined.

AIM

To evaluate a new 20-min immunochromatography method (RAPIRUN H. pylori Antibody) for the presence of anti-H. pylori IgG in urine.

METHODS

We used the (13)C-urea breath test to establish H. pylori status. We evaluated the urine test among 104 subjects including 43 with H. pylori infection confirmed by repeatedly positive urea breath tests and 61 H. pylori-negative subjects with repeatedly negative urea breath tests. Forty-one of the 43 subjects with H. pylori infection had a positive rapid urine test with two false negative tests. There were two false positive tests among the 61 with repeatedly negative urea breath tests. The sensitivity, specificity, positive and negative predictive values for the rapid urine test were 95.3%, 96.7%, 95.3%, and 96.7%, respectively. The kit was easy to use and required no special equipment.

CONCLUSIONS

The rapid immunochromatography method for determination of anti-H. pylori IgG proved to be reliable with excellent sensitivity and specificity and is likely to be useful for both clinical and epidemiological studies.

HDL and the inflammatory response induced by LDL-derived oxidized phospholipids

Oxidation of low density lipoprotein (LDL) phospholipids containing arachidonic acid at the sn-2 position occurs when a critical concentration of "seeding molecules" derived from the lipoxygenase pathway is reached in LDL. When this critical concentration is reached, the nonenzymatic oxidation of LDL phospholipids produces a series of biologically active, oxidized phospholipids that mediate the cellular events seen in the developing fatty streak. Normal high density lipoprotein (HDL) contains at least 4 enzymes as well as apolipoproteins that can prevent the formation of the LDL-derived oxidized phospholipids or inactivate them after they are formed. In the sense that normal HDL can prevent the formation of or inactivate these inflammatory LDL-derived oxidized phospholipids, normal HDL is anti-inflammatory. HDL from mice that are genetically predisposed to diet-induced atherosclerosis became proinflammatory when the mice are fed an atherogenic diet, injected with LDL-derived oxidized phospholipids, or infected with influenza A virus. Mice that were genetically engineered to be hyperlipidemic on a chow diet and patients with coronary atherosclerosis, despite normal lipid levels, also had proinflammatory HDL. It is proposed that LDL-derived oxidized phospholipids and HDL may be part of a system of nonspecific innate immunity and that the detection of proinflammatory HDL may be a useful marker of susceptibility to atherosclerosis.

RNA CUG repeats sequester CUGBP1 and alter protein levels and activity of CUGBP1

An RNA CUG triplet repeat binding protein, CUGBP1, regulates splicing and translation of various RNAs. Expansion of RNA CUG repeats in the 3'-untranslated repeat of the mutant myotonin protein kinase (DMPK) mRNA in myotonic dystrophy (DM) is associated with alterations in binding activity of CUGBP1. To investigate whether CUGBP1 is directly affected by expansion of CUG repeats in DM tissues, we examined the intracellular status of CUGBP1 in DM patients as well as in cultured cells over expressing RNA CUG repeats. The analysis of RNA-protein complexes showed that, in control tissues, the majority of CUGBP1 is free of RNA, whereas in DM patients the majority of CUGBP1 is associated with RNA containing CUG repeats. Similarly to DM patients, overexpression of RNA CUG repeats in cultured cells results in the re-allocation of CUGBP1 from a free state to the RNA.protein complexes containing CUG repeats. CUG repeat-dependent translocation of CUGBP1 into RNA-protein complexes is associated with increased levels of CUGBP1 protein and its binding activity. Experiments with cyclohexamide-dependent block of protein synthesis showed that the half-life of CUGBP1 is increased in cells expressing CUG repeats. Alteration of CUGBP1 in DM is accompanied by alteration in translation of a transcription factor CCAAT/enhancer-binding protein beta (C/EBPbeta), which has been previously described to be a target of CUGBP1. Analysis of C/EBPbeta isoforms in DM patients with altered levels of CUGBP1 showed that translation of a dominant negative isoform, LIP, is induced by CUGBP1. Results of this paper demonstrate that the expansion of CUG repeats in DM affects RNA-binding proteins and leads to alteration in RNA processing.

Expression of the urokinase plasminogen activator receptor is transiently required during "priming" of PC12 cells in nerve growth factor-directed cellular differentiation

We previously identified the urokinase plasminogen activator receptor (UPAR) as a gene induced by nerve growth factor (NGF), but not by epidermal growth factor (EGF), in PC12 cells (Farias-Eisner et al. [2000] J. Neurosci. 20:230-239). Antisense oligonucleotides for the UPAR mRNA or an antibody directed against UPAR protein, added simultaneously with NGF, block NGF-induced morphological and biochemical differentiation of PC12 cells. In this report, we show that anti-UPAR antibody blocks morphological differentiation and the expression of two NGF-specific secondary response genes, collagenase-1 and transin, in PC12 cells only during the first 2 hr following NGF exposure. These data suggest that induced UPAR expression is required only over a short period of time following exposure to NGF for the differentiation program in PC12 cells to proceed. For two models of "primed" PC12 cells, we found that UPAR expression and function are not required for NGF-induced differentiation. UPAR and the secondary response genes collagenase-1 and transin are not induced in "primed" PC12 cells in response to NGF, and anti-UPAR antibody does not block morphological differentiation in these cells. Our data suggests that UPAR is required only transiently during the "priming" of PC12 cells in NGF-induced PC12 cell differentiation.

Standards for the function of an academic 12-lead electrocardiographic core laboratory

An academic 12-lead electrocardiogram (ECG) core laboratory aims to provide the highest possible quality ECG recording, measurement, and storage to aid clinicians in research into important cardiovascular outcomes and to maximize the credibility of scientific results based solely, or in part, on ECG data. This position paper presents a guide for the structure and function of an academic ECG core laboratory. The key functional aspects are: 1) Data collection, 2) Staff composition, 3) Diagnostic measurement and definition standards, 4) Data management, 5) Academic considerations, 6) Economic consideration, and 7) Accreditation. An ECG Core Laboratory has the responsibility for rapid and accurate analysis and responsible management of the electrocardiographic data in multicenter clinical trials. Academic Laboratories, in addition, provide leadership in research protocol generation and production of research manuscripts for submission to the appropriate peer-review journals.

Characteristics of HIV-1-infected patients with CD4:CD8 lymphocyte ratio normalization on antiretroviral therapy

Antiretroviral therapy for human immunodeficiency virus (HIV)-infection results in normalization of CD4:CD8 T-lymphocyte ratio in about 6% of cases. The T-cell ratio normalization on therapy was associated with a baseline CD4 of over 350 cells per microliter and a T-cell ratio of over 0.5 (for each, p < 0.01), but not with the current level of viral load suppression or compliance with clinic appointments (for each, p > 0.05). The patients with T-cell ratio normalization had a baseline median CD4 count of 428 cells per microliter (range, 353-883 cells per microliter) and a median T-cell ratio of 0.75 (range, 0.54-0.87). We could not address the effect of baseline viral load on T-cell ratio normalization, but there was no association with age, gender, race, HIV risk factor, or the length of antiretroviral therapy.

Molecular heterogeneity of protein kinase C expression in human ventricle

OBJECTIVE

Although activation of protein kinase C (PKC) modulates the function of normal cardiac myocytes and likely plays a role in the pathogenesis of cardiomyopathic disease states, the molecular basis of PKC expression in human ventricle has not been examined in detail.

METHODS

We have performed Western analysis and immunohistochemistry on explanted human cardiac tissue from nondiseased and diseased specimens using isoform-specific antibodies directed against all known PKC isozymes.

RESULTS

In homogenates from left and right ventricle, all isoforms except PKC-gamma and theta were detected by immunoblotting, with confirmation using a second antibody directed against a different epitope when possible. For PKC-betaII, delta, and epsilon, data indicated that these isoforms were variably phosphorylated in vivo, resulting in multiple bands during immunoblotting. Because of potential antibody cross-reactivity, reverse transcriptase polymerase chain reaction (RT-PCR) was performed which confirmed expression of PKC-alpha, betaI, and zeta. Immunohistochemistry demonstrated that all isoforms detected in ventricular homogenate by Western analysis could be localized to cardiac myocytes. From a methodologic standpoint, significant degradation of PKC isoforms could be demonstrated when samples were either frozen or allowed to remain at room temperature, compared to immediate subcellular fractionation.

CONCLUSIONS

These findings indicate that the PKC expression in human ventricular myocytes is remarkably diverse, with multiple conventional, novel, and atypical isoforms present, and highlight the importance of sample preparation in comparative studies of PKC isoform expression.

Acute volume expansion and salt-loading studies in rats. The role of atrial natriuretic peptide and catecholamines

Differences have been postulated for the mechanism of natriuresis due to atrial natriuretic peptide (ANP), salt loading with high salt diet (HS) and acute volume expansion (AcVE), in particular between AcVE and ANP based on the observed synergism between the two. Therefore the effects of and the interaction between the three were investigated in rats. ANP and AcVE produced the same natriuresis in HS as in normal salt (NS) rats and, in both, the actions of ANP and AcVe were significantly additive showing similarity in mechanisms. Synergism [(AcVE + ANP) - AcVE] was, however, present only in the NS rats. Proximal tubular sodium transport was the same with AcVE and ANP+AcVE suggesting that synergism is a property of more distal nephron segments. In conscious HS rats, plasma ANP was significantly less but natriuresis was higher than in NS rats. ANP therefore probably has some causative role in the natriuresis of AcVE but none in that of HS loading. Urinary dopamine was significantly increased by HS and further increased by AcVE in both NS and HS rats, the relationship between dopamine and natriuresis being significantly positive (r2 = 0.328) reaching equivalent levels in both NS and HS rats. Systemic benserazide prevented the increase in urinary dopamine but only attenuated the natriuresis of AcVE. We conclude that HS does not potentiate the natriuresis of AcVE or ANP, synergism between AcVE and ANP is not a proximal tubule event and dopamine accounts for significant natriuresis of VE in addition to other natriuretic factors.

The added diagnostic value of automated QT-dispersion measurements and automated ST-segment deviations in the electrocardiographic diagnosis of acute cardiac ischemia

The purpose of this study was to determine the added value of automated QT dispersion and ST-segment measurements to physician interpretation of 12-lead electrocardiograms (ECGs) in patients with chest pain. To date, poor reproducibility of manual measurements and lack of shown added value have limited the clinical use of QT dispersion. Twelve-lead ECGs (n = 1,161) from the Milwaukee Prehospital Chest Pain Database were independently classified by 2 physicians into 3 groups (acute myocardial infarction (AMI), acute cardiac ischemia (ACI), or nonischemic), and their consensus was obtained. QT-end and QT-peak dispersions were measured by a computerized system. The computer also identified ST-segment deviations. Sensitivity, specificity, and positive predictive values (PPVs) and negative predictive values (NPV) for AMI and ACI were evaluated independently and in combinations. For AMI, physicians' consensus classification was remarkably good (sensitivity, 48%, specificity, 99%). Independent classification by QT-end and QT-peak dispersions or ST deviations was not superior to the physicians' consensus. Optimal classification occurred by combining automated QT-end dispersion and ST deviations with physicians' consensus. This combination increased sensitivity for the diagnoses of AMI by 35% (65% vs 48%, P < .001) and ACI by 55% (62% vs 40%, P < .001) compared with physicians' consensus, while maintaining comparable specificity. This study supports a potential clinical role for automated QT dispersion when combined with other diagnostic methods for detecting AMI and ACI.

Dual-label immunohistochemical study of interleukin-4-and interferon-gamma-expressing cells within the pancreas of the NOD mouse during disease acceleration with cyclophosphamide

Beta cell destruction has been shown to occur when rodent or human islets are exposed in vitro to inflammatory cytokines, such as interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). Other cytokines such as interleukin-4 (IL-4) or interleukin-10 (IL-10), when given to NOD mice, prevent insulin-dependent diabetes mellitus (IDDM). In this study, we have employed immunofluorescence histochemistry to study the expression of IFN-gamma and IL-4 in the pancreas of female NOD mice at various time-points (days 0, 4, 7, 11 and at onset of diabetes) following disease acceleration with cyclophosphamide (Cy). Dual-label confocal and light microscopy were employed to determine the precise cellular sources of the two cytokines. IL-4 immunolabelling was observed in a few immune cells at days 0, 4, and 7 within the pancreatic islets but in larger numbers at day 11 and at onset of diabetes. The cytokine was co-localized predominantly in CD4 cells, while only a small minority of CD8 cells and macrophages also expressed IL-4. At days 0, 4, 7 and 11, weak to moderate immunolabelling for IL-4 was also observed in beta cells. In contrast, immunolabelling for IFN-gamma within the islets was not observed until day 11 and this labelling persisted at onset of diabetes. It was immunolocalized in macrophages and to a lesser extent in CD4 cells. Only a few CD8 cells were immunopositive for IFN-gamma. At day 11, a proportion of beta cells showed weak immunolabelling for IFN-gamma. During the study period, immunolabelling for IFN-gamma was also observed in a proportion of endothelial cells located in the intra-islet and exocrine regions of Cy and diluent-treated mice. From day 11 onwards, both the cytokines were observed in some of the peri-vascular regions. Our results demonstrate that during Cy-induced diabetes, there is increasing expression of both IL-4 and IFN-gamma in specific immune cells within the inflamed islets in the late prediabetic stage and at onset of diabetes. Further studies are required to correlate our protein immunohistochemical findings with in situ cytokine gene expression and to determine whether there is a clear Th1 cytokine protein bias at clinical onset of diabetes and immediately preceding it.

Skeletal muscle sodium channel gating in mice deficient in myotonic dystrophy protein kinase

Myotonic dystrophy, a progressive autosomal dominant disorder, is associated with an expansion of a CTG repeat tract located in the 3'-untranslated region of a serine/threonine protein kinase, DMPK. DMPK modulates skeletal muscle Na channels in vitro, and thus we hypothesized that mice deficient in DMPK would have altered muscle Na channel gating. We measured macroscopic and single channel Na currents from cell-attached patches of skeletal myocytes from mice heterozygous (DMPK(+/-)) and homozygous (DMPK(-/-)) for DMPK loss. In DMPK(-/-) myocytes, Na current amplitude was reduced because of reduced channel number. Single channel recordings revealed Na channel reopenings, similar to the gating abnormality of human myotonic muscular dystrophy (DM), which resulted in a plateau of Na current. The gating abnormality deteriorated with increasing age. In DMPK(+/-) muscle there was reduced Na current amplitude and increased Na channel reopenings identical to those in DMPK(-/-) muscle. Thus, these mouse models of complete and partial DMPK deficiency reproduce the Na channel abnormality of the human disease, providing direct evidence that DMPK deficiency underlies the Na channel abnormality in DM.

Anaesthesia for caesarean section in a patient with Eisenmenger's syndrome

Eisenmenger's syndrome was originally described in 1897 and redefined by Wood in 1958. This syndrome includes pulmonary hypertension with reversed or bi-directional shunt associated with septal defects or a patent ductus arteriosus. A 27-year-old G2 PO with Eisenmenger's syndrome presented to the hospital for management at 17 weeks of pregnancy. She was advised termination of pregnancy but she refused. An elective caesarean section was performed successfully under general anaesthesia uneventfully at 29 weeks due to severe intrauterine growth retardation (IUGR). Patient's postoperative complications like pulmonary thromboembolism, the advantages and disadvantages of anticoagulation are discussed. Pregnancy carries substantial maternal and fetal risk for patients with pulmonary hypertension and Eisenmenger's syndrome. Although pregnancy should be discouraged in women with Eisenmenger's syndrome it can be successful.