Reverse remodeling of cardiac myocyte hypertrophy in hypertension and failure by targeting of the renin-angiotensin system

BACKGROUND

ACE inhibitors (ACEIs) and angiotensin II type 1 (AT(1)) receptor blockers are effective in reducing left ventricular mass in hypertension and heart failure. However, the ability of these drugs to reverse excessive myocyte lengthening and transverse growth in heart failure is unknown.

METHODS AND RESULTS

L-158,809 (an AT(1) blocker; AT(1)), enalapril (an ACEI), and hydralazine (a vasodilator) were administered to spontaneously hypertensive heart failure rats between 6 and 10 months of age (early treatment) and between 18 and 22 months of age (late treatment). After 4 months of treatment, hemodynamics and chamber dimensions were collected before left ventricular myocyte isolation and subsequent analysis of myocyte shape. Each drug reduced systolic blood pressures to normal values. In the early and late studies, the ACEI reduced myocyte volume. Myocyte length was also reduced in the late study. However, the AT(1) was most effective in reversing myocyte dimensions to near-normal values in both studies. Hydralazine was ineffective in reducing cell size but arrested progression of myocyte lengthening in the late study. Changes in myocyte shape reflected alterations in chamber dimensions and wall thickness.

CONCLUSIONS

Reversal of myocyte hypertrophy was produced in hypertensive/heart failure rats with an AT(1). The ACEI was effective but to a lesser extent. Results indicate that it is possible to significantly reverse myocyte remodeling pharmacologically even if therapy is initiated near the onset of failure. Further work is needed to determine whether similar results can be obtained in humans.

Reduction of cardiac volume in left-breast treatment fields by respiratory maneuvers: a CT study

PURPOSE

A previous study of healthy female volunteers suggested that deep inspiratory breath holding can reduce the cardiac volume in the treatment portals for left-breast cancer treatment. The reduction of irradiated cardiac volume may be important considering the reported late cardiac morbidity and mortality and the frequent coexistent use of potentially cardiotoxic chemotherapy in breast cancer patients. In the present study, we evaluated the heart volume in the fields and, thus, the true benefit of this respiratory maneuver in breast cancer patients undergoing CT simulation.

MATERIALS AND METHODS

Fifteen patients (median age, 53) were studied. For each patient, CT scans were performed both when the patient breathed normally (quiet respiration) and when the patient held her breath after a deep inspiration. Tangential fields were planned using the same medial, lateral, superior, and inferior borders on skin for the normal breathing and the breath-holding configurations. The cardiac and left-lung volumes within the tangential fields were calculated for both breathing configurations. Multiple scan series were performed for the breath-holding configuration to provide a more accurate delineation of the cardiac tissue and to study the reproducibility of the patient's position between different cycles of deep inspiration.

RESULTS

None of the patients had difficulty holding her breath for 20 s. The cardiac volume in the field was reduced (-86 +/- 24%; p < 0.001) when patients held their breath after a deep inspiration compared to when breathing normally. For 7 patients (47%), deep inspiration moved the heart completely out of the radiation fields. The expansion of the lung tissue due to deep inspiration also increased the absolute lung volume in the tangential fields (183 cm(3) vs 97 cm(3), p < 0.001). However, the fractional volume of the left lung in the field was essentially unchanged. For all but 1 patient, the maximum difference between the external body contours from different breath holding cycles was 5 mm and occurred at the lateral aspect of the breast. At the medial aspect, as indicated by the position of the midline marker, the variations were well within the currently accepted tolerance for patient positioning during tangential treatment.

CONCLUSIONS

Deep-inspiration breath holding substantially reduces cardiac volume in the tangential fields for left-sided breast cancer treatment. The variation between patient positions at different cycles of breath holding was found to be reasonably small. Therefore, it appears feasible to reduce cardiac radiation by treating patients with intratreatment minifractions lasting 10-15 s while patients hold their breath.

Human Slug is a repressor that localizes to sites of active transcription

Snail/Slug family proteins have been identified in diverse species of both vertebrates and invertebrates. The proteins contain four to six zinc fingers and function as DNA-binding transcriptional regulators. Various members of the family have been demonstrated to regulate cell movement, neural cell fate, left-right asymmetry, cell cycle, and apoptosis. However, the molecular mechanisms of how these regulators function and the target genes involved are largely unknown. In this report, we demonstrate that human Slug (hSlug) is a repressor and modulates both activator-dependent and basal transcription. The repression depends on the C-terminal DNA-binding zinc fingers and on a separable repression domain located in the N terminus. This domain may recruit histone deacetylases to modify the chromatin and effect repression. Protein localization study demonstrates that hSlug is present in discrete foci in the nucleus. This subnuclear pattern does not colocalize with the PML foci or the coiled bodies. Instead, the hSlug foci overlap extensively with areas of the SC-35 staining, some of which have been suggested to be sites of active splicing or transcription. These results lead us to postulate that hSlug localizes to target promoters, where activation occurs, to repress basal and activator-mediated transcription.

Dehydroepiandrosterone sulfate (DHEAS) counteracts decremental effects of corticosterone on dentate gyrus LTP. Implications for depression

It is well-established that levels of corticosterone sufficient to occupy Type II glucocorticoid receptors produce a decrement in long-term potentiation (LTP) in the dentate gyrus of the hippocampus in rats. In the present series of experiments we investigate the interaction of corticosterone and the neurosteroid dehydroepiandrosterone sulfate (DHEAS) on LTP in the rat dentate gyrus. In confirmation of previous studies, we found that corticosterone (2 mg/kg) had decremental effects on LTP. However, simultaneous injection of corticosterone and DHEAS (30 mg/kg) elicited excitatory post-synaptic potentials and population spikes that were not significantly different from those observed in control animals. The results are discussed in terms of the interaction of the two hormones, the agonist effects of DHEAS on sigma receptors, and their relation with the antidepressant effects of DHEA.

Activation of spinal cannabinoid 1 receptors inhibits C-fibre driven hyperexcitable neuronal responses and increases [35S]GTPgammaS binding in the dorsal horn of the spinal cord of noninflamed and inflamed rats

The analgesic potential of cannabinoid (CB) receptor agonists is of clinical interest. Improved understanding of the mechanisms of action of cannabinoids at sites involved in the modulation of acute and sustained inflammatory nociceptive transmission, such as the spinal cord, is essential. In vivo electrophysiology was used to compare the effect of the synthetic CB agonist, HU210, on acute transcutaneous electrical-evoked responses of dorsal horn neurons of noninflamed anaesthetized rats and anaesthetized rats with a peripheral carrageenin inflammation. CB receptor G-protein coupling in lumbar spinal cord sections of noninflamed and carrageenin-inflamed rats was studied with in vitro autoradiography of guanylyl 5'-[gamma-[35S]thio]triphosphate ([35S]GTPgammaS) binding. Spinal HU210 significantly inhibited the C-fibre-mediated late (300-800 ms) postdischarge response of dorsal horn neurons of noninflamed and carrageenin-inflamed rats; the CB1 receptor antagonist SR141716A blocked the effect of HU210. HU210 had limited effects on A-fibre-evoked dorsal horn neuronal responses of both groups of rats. HU210 significantly increased [35S]GTPgammaS binding in the dorsal horn of the spinal cord of both groups of rats compared with basal [35S]GTPgammaS binding; SR141716A blocked these effects. The predominant effect of spinal HU210, via CB1 receptor activation, was on the C-fibre driven postdischarge responses, a measure of neuronal hyperexcitability following repetitive C-fibre stimulation. Sustained, but not enhanced, antinociceptive effects of HU210 following carrageenin inflammation are reported; CB receptor G-protein coupling was not altered by inflammation. These results strengthen the body of evidence suggesting CB agonists may be an important novel analgesic approach for the treatment of sustained pain states.

The Morphologies of the Small Magellanic Cloud

We compare the distribution of stars of different spectral types, and hence mean age, within the central SMC and find that the asymmetric structures are almost exclusively composed of young main-sequence stars. Because of the relative lack of older stars in these features and the extremely regular distribution of red giant and clump stars in the SMC central body, we conclude that tides alone are not responsible for the irregular appearance of the central SMC. The dominant physical mechanism in determining the current-day appearance of the SMC must be star formation triggered by a hydrodynamic interaction between gaseous components. These results extend the results of population studies (see Gardiner & Hatzidimitriou) inward in radius and also confirm the suggestion of the spheroidal nature of the central SMC based on kinematic arguments (Dopita et al.; Hardy, Suntzeff, & Azzopardi). Finally, we find no evidence in the underlying older stellar population for a "bar" or "outer arm," again supporting our classification of the central SMC as a spheroidal body with highly irregular recent star formation.

The gene for May-Hegglin anomaly localizes to a <1-Mb region on chromosome 22q12.3-13.1

The May-Hegglin anomaly (MHA) is an autosomal dominant platelet disorder of unknown etiology. It is characterized by thrombocytopenia, giant platelets, and leukocyte inclusion bodies, and affected heterozygotes are predisposed to bleeding episodes. The MHA gene has recently been localized, by means of linkage analysis, to a 13.6-cM region on chromosome 22, and the complete chromosome 22 sequence has been reported. We recently performed a genome scan for the MHA gene in 29 members of a large, multigenerational Italian family, and we now confirm that the MHA locus is on chromosome 22q12. 3-13.1. The maximal two-point LOD score of 4.50 was achieved with the use of marker D22S283, at a recombination fraction of.05. Haplotype analysis narrowed the MHA critical region to 6.6 cM between markers D22S683 and D22S1177. It is of note that the chromosome 22 sequence allowed all markers to be ordered correctly, identified all the candidate genes and predicted genes, and specifically determined the physical size of the MHA region to be 0. 7 Mb. These results significantly narrow the region in which the MHA gene is located, and they represent the first use of chromosome 22 data to positionally clone a disease gene.

Is there a coherent social conception of disability?

Is there such a thing as a social conception of disability? Recently two writers in this journal have suggested not only that there is a coherent social conception of disability but that all non-social conceptions, or "medical models" of disability are fatally flawed. One serious and worrying dimension of their claims is that once the social dimensions of disability have been resolved no seriously "disabling" features remain. This paper examines and rejects conceptions of disability based on social factors but notes that physical and mental conditions which disadvantage the individual have social dimensions.

Mental health. Facing hard truths

A survey of 104 mental health units found that half did not have policies on treatment of detained patients from black and ethnic minority groups. Almost three-quarters had no policy for dealing with racial harassment of black and ethnic-minority patients. 11 percent of patients whose notes were examined had reported racial harassment.

Self-harm: cutting the bad out of me

The practice of self-harm is increasing in the United Kingdom, accounting for the highest number of acute medical admissions for women. The medical and nursing response to repeaters, set within a climate of dwindling emergency and accident resources, has been one of impatience, frustration, and hostile care. The author undertook a correspondence study with 6 women who regularly self-harmed. The women claimed that medical and nursing professionals viewed their self-harm as irrational and illogical. However, a qualitative examination of the motivations and interests of all parties reveals that self-harm acts possess situated internal logic, whereas professionals tend to use rational logic in attempting to understand them.

Total and specific IgE (house dust mite and intestinal helminths) in asthmatics and controls from Gondar, Ethiopia

BACKGROUND

The role, if any, of parasitosis in the development of asthma remains incompletely understood; both 'protective' and 'predictive' associations have been reported. We report a study which examined immunoglobulin (Ig) E responses to two common helminths in asthmatics living in Ethiopia.

OBJECTIVE

To compare the frequencies of specific IgE antibodies to Ascaris and Necator species and to Der p 1 among 84 adult asthmatics and a referent group of nonasthmatics.

METHODS

A case-control analysis.

RESULTS

Total IgE levels were not different between the two groups. The presence of specific IgE to Der p 1 was strongly associated with asthma (P = 0.001). Raised levels of Ascaris-(P = 0.010) and Necator- (P = 0.001) specific IgE antibodies were more common among referents; there were no associations between specific IgE production to Der p 1 and either of the two parasites.

CONCLUSION

These findings confirm the association between Der p 1 sensitization and asthma among urban, adult Ethiopians. While they also indicate a negative relationship with two indicators of helminth infestation it appears that this is not mediated through the immunological response to common aeroallergens.

Is apoptosis present in progression to chronic hypertensive heart failure?

BACKGROUND

Cardiomyocyte apoptosis is believed to occur in hypertension. Isolated myocyte data from spontaneously hypertensive heart failure (SHHF) rats, however, suggest that significant myocyte loss does not occur in this model. To investigate this issue further, heart sections from failing and nonfailing SHHF rats were examined by using in situ terminal deoxynucleotidyltransferase-mediated 2'-deoxyuridine 5'-triphosphate nick end-labeling (TUNEL). Additional hearts were optimally fixed by perfusion with glutaraldehyde and histologically examined for evidence of myocyte damage or loss.

METHODS AND RESULTS

Five Sprague-Dawley (SD) rats, 8 failing SHHF rats, and 6 nonfailing SHHF rats were perfusion-fixed with formaldehyde and used for TUNEL assay. Heart sections from each group were also treated with DNase for positive controls. There were no significant differences in the number of TUNEL-positive cells in SD, failing SHHF, and nonfailing SHHF rats. Additionally, extensive screening of 1-microm sections of optimally fixed failing hearts revealed little evidence of myocyte loss or nuclear characteristics suggestive of apoptosis.

CONCLUSION

Apoptosis does not appear to be an important component of myocardial remodeling in SHHF rats during hypertrophy or end-stage heart failure. Examination of myocyte nuclear structure by high-resolution microscopy of optimally fixed tissues is recommended as an alternative approach to study apoptosis.

Asthma and wheezing among Norwegian elite athletes

PURPOSE

The objectives were to estimate the prevalence of self-reports of asthma and wheezing among Norwegian elite athletes compared with the general population and to estimate the associations between asthma and types of sports, exercise and team level.

METHODS

The study population included all Norwegian elite athletes on the national junior and senior teams in 1997 (N = 1620) and a random sample from the general population (N = 1680). The surveys included items for asthma, respiratory symptoms, the history of participation in sports, sports events, and exercise and team level. The associations between the exposure variables and the outcomes adjusting for potential confounding factors were estimated using logistic regression. Crude (c) and adjusted odds ratio (aOR) with 95% confidence interval (CI) are presented.

RESULTS

The prevalence of asthma was greater among athletes (10.0%) compared with that in the general population (6.9%) and remained so after controlling for confounders, aOR = 1.5 (95%CI 1.1-2.1). The risk of asthma was highest in sports requiring strength and endurance. This was the case for comparisons between athletes and the general population, aOR = 3.5 (1.6-7.6) for strength and aOR = 2.2 (1.4-3.5) for endurance sports. Comparisons within the sample of athletes using technical sports as the reference category revealed similar results, aOR = 3.0 (1.1-8.0) and aOR = 2.0 (1.0-4.3), respectively. Furthermore, asthma was more common among female than male athletes (aOR 1.7 (1.1-2.7)). Training more than 20 h x wk(-1) was associated with asthma when compared with levels of training less than 10 h x wk(-1) (aOR 1.9 (1.0-4.1)).

CONCLUSION

These results indicate that asthma is more common among athletes compared with the general population. Asthma among athletes may define a subgroup of asthma cases for whom etiology is related to extensive exercise.

Lethal licorice

The human body's response to extreme stress is complex and this patient's experience illustrates just how traumatic it can be both physiologically and psychologically. While Alan's experience was extreme and unusual, it serves to emphasise the importance of diet and health maintenance particularly for the cardiac patient.

Necropsy diagnosis of myocarditis: a retrospective study using CD45RO immunohistochemistry

AIM

To use CD45RO immunohistochemistry to investigate the numbers of T lymphocytes found in sections of myocardium from a routine necropsy series, and to determine the incidence of myocarditis in this series.

METHODS

Myocardial sections from 163 routine hospital necropsies were stained with CD45RO and the numbers of positive lymphocytes/mm2 were counted. The results were correlated with the H/E opinion and the clinical context of the necropsy.

RESULTS

Most (143) cases showed low numbers (0-3) of CD45RO positive lymphocytes/mm2. Fifteen cases showed 7-13 positive lymphocytes/mm2, comprising a wide variety of clinical conditions, generally with no specific cardiac pathology. Five cases showed 14 or more positive lymphocytes/mm2, comprising one case of active myocarditis, three cases of cardiac transplant rejection, and one post-transplant lymphoproliferative disorder, all conditions in which large numbers of lymphocytes would be expected.

CONCLUSIONS

The incidence of myocarditis in our series was 0.6%. In most cases the normal myocardium has a low T lymphocyte count (0-3/mm2). In some cases immunohistochemistry shows more positive cells than would have been expected on light microscopy. Immunohistochemistry is a useful and reliable means of confirming a diagnosis of myocarditis. The results support the conclusion of the 1997 ISFC task force that 14 or more lymphocytes or macrophages/mm2 of myocardium in the appropriate clinical context is a reliable threshold for the diagnosis of chronic myocarditis.

Anal sphincter conservation for patients with adenocarcinoma of the distal rectum: long-term results of radiation therapy oncology group protocol 89-02

PURPOSE

To assess the outcome of a multi-institutional, national cooperative group study attempting functional preservation of the anorectum for patients with limited, distal rectal cancer.

METHODS AND MATERIALS

Between September 21, 1989 and November 1, 1992, a Phase II trial of sphincter-sparing therapy was conducted for patients with clinically mobile rectal cancers located below the pelvic peritoneal reflection. Protocol treatment was designed for patients who were, in the judgement of their attending surgeon, unsuitable for anal sphincter conservation in the context of anterior resection, and would have required abdominoperineal resection (APR) as conventional surgical therapy. Primary cancers were estimated to be 4 cm or less in largest clinical diameter, and occupied 40% or less of the rectal circumference. Chest radiography and computerized axial tomography (CT) of the abdomen and pelvis excluded patients with overt lymphatic or hematogenous metastases. Protocol surgery was intended to remove the primary cancer by en-bloc, transmural excision of an ellipse of rectal wall by transanal, transcoccygeal, or trans-sacral technique, while conserving the anal sphincter. Based on tumor size, T classification, grade, and adequacy of surgical margins, patients were allocated to one of three treatment assignments: observation, or adjuvant treatment with 5-fluorouracil (5-FU) and one of two different dose levels of local-regional radiation. After completion of protocol therapy, patients were observed with follow-up that included periodic general physical and rectal examination, determinations of CEA, abdominopelvic CT, chest radiography, and surveillance endoscopy. Sixty-five eligible and analyzable patients were registered.

RESULTS

With minimum follow-up of 5 years and median follow-up of 6.1 years, 11 patients have failed: 3 patients recurred local-regionally only, 3 patients had distant failure alone, and 5 patients manifested local-regional and distant failure. Eight patients died of intercurrent illness. Local-regional failure correlated with T-category revealed: T1 1/27 (4%), T2 4/25 (16%), and T3 3/13 (23%). Local-regional failure escalated with percentage involvement of the rectal circumference: 2/31 (6%) among patients with cancers involving 20% or less of the rectal circumference, and 6/34 (18%) among patients with cancers involving 21-40% of the circumference. Distant dissemination rose with T-category with 1/27 (4%) T1, 3/25 (12%) T2, and 4/13 (31%) T3 patients manifesting hematogenous spread. Eight patients (12%) required temporary or permanent colostomy. Five of 8 patients with local-regional recurrence achieved local-regional control with management including surgery, although 4 of these patients subsequently developed distant dissemination. Three patients (5%) had persistent, uncontrolled, local disease. Actuarial freedom from pelvic relapse at 5 years is 88% based on the entire study population, and 86% for the less favorable patients treated with adjuvant radiation and 5-FU.

CONCLUSION

Conservative, sphincter-sparing therapy is a feasible alternative treatment for selected patients with limited cancer involving the middle and lower rectum. Risk of both local and distant failure appears to escalate with increasing T-category (depth of invasion). Results achieved in the multi-institutional, cooperative group setting approximate results reported from single institutions.

Endotension: an explanation for continued AAA growth after successful endoluminal repair

PURPOSE

To present and analyze several cases that illustrate persistent sac pressurization following endovascular abdominal aortic aneurysm (AAA) repair.

METHODS AND RESULTS

Four patients with successful endovascular AAA exclusion presented in follow-up with an expanding aneurysm. Two had initial sac diameter decrease, but by 18 and 24 months, respectively, the AAA had enlarged and become pulsatile. There was no endoleak evident, but the proximal attachment stents had mig rated distally in both cases. One patient developed endoleak with aneurysm expansion at 6 months; contained rupture occurred at 12 months. The last case had slowly evolving aneurysm expansion over 36 months but no endoleak. All endografts were removed and successfully replaced with conventional grafts. Intrasac thrombus was implicated as the means of pressure transmission that precipitated AAA expansion in these cases.

CONCLUSIONS

Excluded AAAs can increase in size owing to persistent or recurrent pressurization (endotension) of the sac even when there is no evidence of endoleak. One proposed mechanism is pressure transmission via thrombus that lines the attachment site. Endotension may also represent an indiscernible, very low flow endoleak that allows blood to clot at the source of leakage.