Prevalence of smoking during pregnancy and associated social inequalities in developed countries over the 1995-2020 period: A systematic review

BACKGROUND

Smoking during pregnancy (SDP) is an important source of preventable morbidity and mortality for both mother and child.

OBJECTIVES

The aim of this study was to describe changes in the prevalence of SDP over the last 25 years in developed countries (Human Development Index >0.8 in 2020) and associated social inequalities.

DATA SOURCES

A systematic review was conducted based on a search in PubMed, Embase and PsycInfo databases and government sources.

STUDY SELECTION AND DATA EXTRACTION

Published studies between January 1995 and March 2020, for which the primary outcome was to assess the national prevalence of SDP and the secondary outcome was to describe related socio-economic data were included in the analysis. The selected articles had to be written in English, Spanish, French or Italian.

SYNTHESIS

The articles were selected after successive reading of the titles, abstracts and full-length text. An independent double reading with intervention of a third reader in case of disagreement allowed including 35 articles from 14 countries in the analysis.

RESULTS

The prevalence of SDP differed across the countries studied despite comparable levels of development. After 2015, the prevalence of SDP ranged between 4.2% in Sweden and 16.6% in France. It was associated with socio-economic factors. The prevalence of SDP slowly decreased over time, but this overall trend masked inequalities within populations. In Canada, France and the United States, the prevalence decreased more rapidly in women of higher socio-economic status, and inequalities in maternal smoking were more marked in these countries. In the other countries, inequalities tended to decrease but remained significant.

CONCLUSIONS

During pregnancy, that is a period described as a window of opportunity, smoking and social vulnerability factors need to be detected to implement targeted prevention strategies aiming at reducing related social inequalities.

[French practical guidelines for the diagnosis and management of IPF - 2021 update, full version]

BACKGROUND

Since the previous French guidelines were published in 2017, substantial additional knowledge about idiopathic pulmonary fibrosis has accumulated.

METHODS

Under the auspices of the French-speaking Learned Society of Pulmonology and at the initiative of the coordinating reference center, practical guidelines for treatment of rare pulmonary diseases have been established. They were elaborated by groups of writers, reviewers and coordinators with the help of the OrphaLung network, as well as pulmonologists with varying practice modalities, radiologists, pathologists, a general practitioner, a head nurse, and a patients' association. The method was developed according to rules entitled "Good clinical practice" in the overall framework of the "Guidelines for clinical practice" of the official French health authority (HAS), taking into account the results of an online vote using a Likert scale.

RESULTS

After analysis of the literature, 54 recommendations were formulated, improved, and validated by the working groups. The recommendations covered a wide-ranging aspects of the disease and its treatment: epidemiology, diagnostic modalities, quality criteria and interpretation of chest CT, indication and modalities of lung biopsy, etiologic workup, approach to familial disease entailing indications and modalities of genetic testing, evaluation of possible functional impairments and prognosis, indications for and use of antifibrotic therapy, lung transplantation, symptom management, comorbidities and complications, treatment of chronic respiratory failure, diagnosis and management of acute exacerbations of fibrosis.

CONCLUSION

These evidence-based guidelines are aimed at guiding the diagnosis and the management in clinical practice of idiopathic pulmonary fibrosis.

HCV cure: an appropriate moment to reduce cannabis use in people living with HIV? (ANRS CO13 HEPAVIH data)

BACKGROUND

Thanks to direct-acting antivirals, hepatitis C virus (HCV) infection can be cured, with similar rates in HCV-infected and HIV-HCV co-infected patients. HCV cure is likely to foster behavioral changes in psychoactive substance use, which is highly prevalent in people living with HIV (PLWH). Cannabis is one substance that is very commonly used by PLWH, sometimes for therapeutic purposes. We aimed to identify correlates of cannabis use reduction following HCV cure in HIV-HCV co-infected cannabis users and to characterize persons who reduced their use.

METHODS

We used data collected on HCV-cured cannabis users in a cross-sectional survey nested in the ANRS CO13 HEPAVIH cohort of HIV-HCV co-infected patients, to perform logistic regression, with post-HCV cure cannabis reduction as the outcome, and socio-behavioral characteristics as potential correlates. We also characterized the study sample by comparing post-cure substance use behaviors between those who reduced their cannabis use and those who did not.

RESULTS

Among 140 HIV-infected cannabis users, 50 and 5 had reduced and increased their use, respectively, while 85 had not changed their use since HCV cure. Cannabis use reduction was significantly associated with tobacco use reduction, a decrease in fatigue level, paying more attention to one's dietary habits since HCV cure, and pre-HCV cure alcohol abstinence (p = 0.063 for alcohol use reduction).

CONCLUSIONS

Among PLWH using cannabis, post-HCV cure cannabis reduction was associated with tobacco use reduction, improved well-being, and adoption of healthy behaviors. The management of addictive behaviors should therefore be encouraged during HCV treatment.

[French practical guidelines for the diagnosis and management of IPF - 2021 update, short version]

BACKGROUND

Since the previous French guidelines were published in 2017, substantial additional knowledge about idiopathic pulmonary fibrosis has accumulated.

METHODS

Under the auspices of the French-speaking Learned Society of Pulmonology and at the initiative of the coordinating reference center, practical guidelines for treatment of rare pulmonary diseases have been established. They were elaborated by groups of writers, reviewers and coordinators with the help of the OrphaLung network, as well as pulmonologists with varying practice modalities, radiologists, pathologists, a general practitioner, a head nurse, and a patients' association. The method was developed according to rules entitled "Good clinical practice" in the overall framework of the "Guidelines for clinical practice" of the official French health authority (HAS), taking into account the results of an online vote using a Likert scale.

RESULTS

After analysis of the literature, 54 recommendations were formulated, improved, and validated by the working groups. The recommendations covered a wide-ranging aspects of the disease and its treatment: epidemiology, diagnostic modalities, quality criteria and interpretation of chest CT, indication and modalities of lung biopsy, etiologic workup, approach to familial disease entailing indications and modalities of genetic testing, evaluation of possible functional impairments and prognosis, indications for and use of antifibrotic therapy, lung transplantation, symptom management, comorbidities and complications, treatment of chronic respiratory failure, diagnosis and management of acute exacerbations of fibrosis.

CONCLUSION

These evidence-based guidelines are aimed at guiding the diagnosis and the management in clinical practice of idiopathic pulmonary fibrosis.

Blood CD9+ B cell, a biomarker of bronchiolitis obliterans syndrome after lung transplantation

Bronchiolitis obliterans syndrome is the main limitation for long-term survival after lung transplantation. Some specific B cell populations are associated with long-term graft acceptance. We aimed to monitor the B cell profile during early development of bronchiolitis obliterans syndrome after lung transplantation. The B cell longitudinal profile was analyzed in peripheral blood mononuclear cells from patients with bronchiolitis obliterans syndrome and patients who remained stable over 3 years of follow-up. CD24^hi CD38^hi transitional B cells were increased in stable patients only, and reached a peak 24 months after transplantation, whereas they remained unchanged in patients who developed a bronchiolitis obliterans syndrome. These CD24^hi CD38^hi transitional B cells specifically secrete IL-10 and express CD9. Thus, patients with a total CD9⁺ B cell frequency below 6.6% displayed significantly higher incidence of bronchiolitis obliterans syndrome (AUC = 0.836, PPV = 0.75, NPV = 1). These data are the first to associate IL-10-secreting CD24^hi CD38^hi transitional B cells expressing CD9 with better allograft outcome in lung transplant recipients. CD9-expressing B cells appear as a contributor to a favorable environment essential for the maintenance of long-term stable graft function and as a new predictive biomarker of bronchiolitis obliterans syndrome-free survival.

[Nagashima-type palmoplantar keratoderma: A little-known palmoplantar keratoderma in Europe]

BACKGROUND

Herein we present a case of palmoplantar keratoderma (PPK) in a young adopted girl of Chinese origin living in France.

OBSERVATION

The patient, aged six years, had presented transgressive PPK since birth, as well as erythema progressing in congestive inflammatory episodes, palmoplantar hyperhidrosis and progressive characteristics (moderate hyperkeratosis in areas of rubbing other than the palms and soles, namely the elbows and knees). Histopathological examination of a skin biopsy revealed a thick epidermis with lengthening and thickening of crests. The epithelium displayed a thick granular layer. Electron microscopy showed hyperorthokeratosis with hypergranulosis and loss of lamellar structure of the keratinosomes, as well as cleavage between corneocytes. Molecular studies showed the presence of two composite heterozygous mutations of the SERPINB7 gene, enabling a diagnosis of Nagashima-type PPK (NPPK) to be made.

DISCUSSION

NPPK is an autosomal recessive disease caused by a mutation in the SERPINB7, a member of the superfamily of serine protease inhibitors. It was described by Nagashima in 1977 with molecular characterisation by Kubo following in 2013. It is the most widespread form of PPK in Asia (with a prevalence of 1.2/10,000 in Japan and 3.1/10,000 in China). It is distinguished from the other PPKs in terms of transgressive soft hyperkeratosis, inflammatory episodes and hyperhidrosis, as well as by its non-progressive nature. In the present case, while the clinical presentation was characteristic, diagnosis was only made thanks to sequencing of a panel of over 50 genes responsible for PPK. The disease is effectively little-known in Europe. This study highlights the increasing importance of diagnostic investigation methods involving the use of gene panels.

[Invasive pulmonary aspergillosis]

INTRODUCTION

Invasive pulmonary aspergillosis (IPA) is an important cause of morbidity and mortality in a wide range of patients. Early recognition and diagnosis have become a major focus in improving the management and outcomes of this life-threatening disease.

BACKGROUND

IPA typically occurs during a period of severe and prolonged neutropenia. However, solid organ transplant recipients, patients under immunosuppressive therapy or hospitalized in intensive care units are also at risk. The diagnosis is suspected in the presence of a combination of clinical, biological and CT scan evidence. The microbiological diagnostic strategy should be adapted to the patient's profile. Conventional methods with culture and species identification remain the standard but early diagnosis has been improved by the use of biomarkers such as galactomannan antigen in serum or in bronchoalveolar lavage.

OUTLOOK

The epidemiology of IPA should change with the increased use of antifungal prophylactic regimens and the arrival of targeted therapies. Other microbiological tools, such as PCR and other biomarkers, are currently being assessed.

CONCLUSIONS

IPA must be considered in a wide range of patients. Its prognosis remains poor despite progress in the microbiological diagnosis and therapeutic management.

High endemism and stem density distinguish New Caledonian from other high-diversity rainforests in the Southwest Pacific

BACKGROUND AND AIMS

The biodiversity hotspot of New Caledonia is globally renowned for the diversity and endemism of its flora. New Caledonia's tropical rainforests have been reported to have higher stem densities, higher concentrations of relictual lineages and higher endemism than other rainforests. This study investigates whether these aspects differ in New Caledonian rainforests compared to other high-diversity rainforests in the Southwest Pacific.

METHODS

Plants (with a diameter at breast height ≥10 cm) were surveyed in nine 1-ha rainforest plots across the main island of New Caledonia and compared with 14 1-ha plots in high-diversity rainforests of the Southwest Pacific (in Australia, Fiji, Papua New Guinea and the Solomon Islands). This facilitated a comparison of stem densities, taxonomic composition and diversity, and species turnover among plots and countries.

KEY RESULTS

The study inventoried 11 280 stems belonging to 335 species (93 species ha-1 on average) in New Caledonia. In comparison with other rainforests in the Southwest Pacific, New Caledonian rainforests exhibited higher stem density (1253 stems ha-1 on average) including abundant palms and tree ferns, with the high abundance of the latter being unparalleled outside New Caledonia. In all plots, the density of relictual species was ≥10 % for both stems and species, with no discernible differences among countries. Species endemism, reaching 89 % on average, was significantly higher in New Caledonia. Overall, species turnover increased with geographical distance, but not among New Caledonian plots.

CONCLUSIONS

High stem density, high endemism and a high abundance of tree ferns with stem diameters ≥10 cm are therefore unique characteristics of New Caledonian rainforests. High endemism and high spatial species turnover imply that the current system consisting of a few protected areas is inadequate, and that the spatial distribution of plant species needs to be considered to adequately protect the exceptional flora of New Caledonian rainforests.

Evaluation of superficially and fully porous particles for HILIC separation of lanthanide–polyaminocarboxylic species and simultaneous coupling to ESIMS and ICPMS

In this work, amide-bonded columns packed with fully porous particles (FPP) and superficially porous particles (SPP) were evaluated to separate lanthanide–polyaminocarboxylic species by hydrophilic interaction liquid chromatography (HILIC), using two model samples of interest in nuclear and other industrial applications. We assessed the gains achieved by reducing the dimensions of the columns along with the size of the FPPs to sub-2 μm and by using sub-3 μm SPP-packed columns. The FPP-packed Acquity column (100 × 2.1 mm; 1.7 μm) performed better than the SPP-packed Accucore column (150 × 2.1 mm; 2.6 μm), with a separation that was two times more efficient and three times shorter, while generating around 30% less in effluent volumes. This column was also coupled simultaneously to electrospray ionisation mass spectrometry (ESIMS) and inductively coupled plasma mass spectrometry (ICPMS). The instrumental set-up was performed in a conventional laboratory, by taking into account the geometrical constraints existing in the laboratory dedicated to radioelement analysis. Furthermore, separation of the series of lanthanide (Ln) species was demonstrated for the first time thanks to the separation mode of hydrophilic interaction liquid chromatography.

Application of sustainable chromatographic strategies to reduce effluent volumes generated by HILIC separation of lanthanide–polyaminocarboxylic acid species.

[MRI of the pulmonary parenchyma: Towards clinical applicability?]

Lung parenchyma has long been considered out of the scope of magnetic resonance imaging (MRI) clinical applicability. However, technological advances have emerged to soluce the technical difficulties and thus, applications in clinical practice have become realistic. Nevertheless, various approaches have been proposed and there is a need to synthetize the most recent literature data in order to envision a rationale to build lung MR protocols for clinical use. In addition, these technological innovations may modify the usual paradigms of lung MRI, which are still not consensual. Thus, lung MR protocols appear to be heterogeneous across expert centers in the current context. In this literature review, we ought to describe a rationale on the need to get an alternative to ionizing imaging modalities, in particular in the follow-up of patients with chronic lung diseases. We will describe the most recent technical advances regarding both morphological and functional MRI. Finally, we will conclude on the clinical applicability of MRI of the pulmonary parenchyma, as a routine or research tool.

Abstract P5-09-13: The effect of bone pain–specific education vs general chemotherapy side-effect education on reported bone pain in patients (pts) with breast cancer receiving chemotherapy and pegfilgrastim

Background: Mild-to-moderate bone pain is the most commonly reported adverse event (AE) associated with pegfilgrastim, but pt education has not been specifically studied in the management of pegfilgrastim-related bone pain. We investigated the effect of pt education on reported bone pain in pts with breast cancer receiving adjuvant or neoadjuvant chemotherapy and pegfilgrastim.

Methods: In this single-blind study, female pts ≥ 18 years of age with newly diagnosed stage I–III breast cancer, planning ≥ 4 cycles of neoadjuvant or adjuvant chemotherapy with pegfilgrastim support starting in cycle 1, were randomized 1:1 to view one of two 2-minute educational DVDs: a general educational DVD (GE-DVD) on chemotherapy side effects or a more specific DVD on bone pain following chemotherapy and pegfilgrastim (BP-DVD). Pts were excluded if they were not able to understand English, were scheduled to receive weekly chemotherapy, had ongoing chronic pain requiring treatment, had received chemotherapy for cancer within the last 5 years, or had previously received G-CSF. Pts were required to watch the DVD on 2 separate days during clinic visits up to and including the visit for pegfilgrastim administration in cycle 1. In each of the four cycles of the study period, pts completed a brief bone pain survey once per day for 5 days, beginning the day they received pegfilgrastim; severity of pain was rated on a scale of 0–10. Pts also recorded any medications taken to alleviate bone pain. Pts were asked about AEs at the beginning of each chemotherapy cycle and at the safety follow-up visit.

Results: Of the 312 pts screened, 304 were enrolled, and of those, 300 received pegfilgrastim in cycle 1: 149 in the GE-DVD arm and 151 in the BP-DVD arm. Baseline demographics and characteristics were largely balanced between the arms, but fewer pts in the GE-DVD arm were Hispanic/Latino (3.4% vs 7.9%). Fewer pts in the GE-DVD arm were ER positive (59.1% vs 69.5%) and PR positive (46.3% vs 59.6%), while more were HER2 positive (30.2% vs 18.5%). Receipt of taxane-based chemotherapy regimens was balanced between the arms. Pt-reported maximum bone pain was similar in the GE-DVD arm vs the BP-DVD arm (cycle 1, 3.2 vs 3.5, P = .3479; across all cycles, 4.1 vs 4.6, P = .2196). Pt-reported mean bone pain was also similar between arms (cycle 1, 1.6 vs 1.8, P = .3188; across all cycles, 1.5 vs 1.6, P = .5846) as was area under the curve for pt-reported bone pain (cycle 1, 6.7 vs 7.6, P = .3346; across all cycles, 6.3 vs 6.6, P = .6255). All-grade bone pain and grade 3/4 bone pain from AE reporting were similar between the arms. Pt-reported bone pain and bone pain from AE reporting were highest in cycle 1; pain decreased thereafter and remained stable in cycles 2, 3, and 4. Bone pain medication usage was similar between the arms; usage was highest in cycle 1 and decreased with each subsequent cycle. Pain therefore appeared to be truly stable in cycles 2, 3, and 4, not just better medicated.

Conclusions: Our bone pain–specific educational program did not improve perceptions of bone pain reported by this pt population. Bone pain was highest in cycle 1, decreased in cycle 2, and then remained stable.

Citation Format: Maxwell CL, Guinigundo AS, Vanni L, Morrow PK, Reiner M, Shih A, Klippel Z, Blanchard E. The effect of bone pain–specific education vs general chemotherapy side-effect education on reported bone pain in patients (pts) with breast cancer receiving chemotherapy and pegfilgrastim. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-09-13.

Not so sweet: autoimmune diabetes mellitus on triple therapy for chronic hepatitis C infection

BACKGROUND

Triple therapy with pegylated interferon, ribavirin and a protease inhibitor has proven efficacy in hepatitis C infection and is currently the standard of care. Interferon-based therapies have been, rarely, associated with the development of Type 1 diabetes mellitus, but few cases have yet been reported in triple therapy for hepatitis C.

CASE REPORT

We describe a case of autoimmune Type 1 diabetes developing in a 23-year-old woman after initiation of triple therapy for chronic hepatitis C virus infection. The patient had the IL-28B gene polymorphism rs12979860 CT genotype, which is associated not only with antiviral therapy response but also with diabetes risk after liver transplantation for hepatitis C.

CONCLUSION

Further studies are required to determine which individual characteristics may identify patients who are at risk of developing Type 1 diabetes when treated with interferon-based regimens for hepatitis C infection.

[Asthma and Mycoplasma pneumoniae]

INTRODUCTION

A growing body of basic and clinical science implicates Mycoplasma pneumonia in asthma, but its exact contribution to asthma development, exacerbation and persistence is as yet unclear.

STATE OF THE ART

M. pneumoniae infection, with the induction of bronchial hyperresponsiveness, seems to be a precipitating factor for asthma development in predisposed subjects. M. pneumoniae has been seen both in acute exacerbation (18-20%) and in chronically infected adults with stable asthma, where it may be enhancing chronic airway inflammation.

PERSPECTIVES

If M. pneumoniae plays a role in the development or progression of asthma, its eradication might influence the clinical course of the disease and improve symptoms. Macrolide treatment, with antimicrobial and anti-inflammatory properties, could have a place in the management of asthma, especially steroid-dependent asthma.

CONCLUSIONS

M. pneumoniae infection seems to be important in asthma pathogenesis and the clinical course of the disease. Difficulty in detecting the pathogen complicates investigations. Ongoing research will further determine the place of macrolide antibiotics in asthma management.

[Iatrogenic cutaneous emphysema]

BACKGROUND

Tracheal perforation following orotracheal intubation is a rare but classic complication of general anaesthesia, and marked cutaneous emphysema can occur. We report a rare case of facial cutaneous emphysema revealed by swelling with pseudovesicles on the eyelids.

CASE REPORT

A 99-year-old woman developed extensive facial swelling with pseudo-vesicles on the upper and lower eyelids following right hip replacement surgery. Swelling of the upper members and thoracic area was also seen. Chest X-rays showed marked cutaneous emphysema of the thoracic wall. Bronchial endoscopy revealed perforation of the posterior aspect of the trachea. The patient was presenting cutaneous emphysema as a result of post-intubation tracheal perforation.

DISCUSSION

We report a rare case of cutaneous emphysema in a 99-year-old woman after tracheal perforation following orotracheal intubation. The significant feature of our case report is the actual manifestation of the condition. Our patient developed swelling of the eyelid with pseudovesicles. When confronted with sudden onset of pseudovesicles of the eyelids after surgery, dermatologists must not misdiagnose cutaneous emphysema and must examine their patient carefully for other clinical signs. Bronchial endoscopy should be undertaken immediately to investigate for tracheal perforation.

Patient compliance in the treatment of Burkitt's lymphoma in rural Zambia: a retrospective study on 80 Burkitt's lymphoma patients in Katete, Zambia

BACKGROUND

In African settings the treatment results of Burkitt's lymphoma (BL) seem to be less favourable compared with Western settings. The aim of this retrospective study was to analyse some factors that affect the treatment of BL.

PATIENTS AND METHODS

Over a 16 year period, data were extracted of 80 patients.

RESULTS

Complete remission 5%, very good partial response 35%, partial response 16%, no response 10%, data missing 34%. Of all patients, 56% did have a positive response to treatment. However, 51% of this subgroup of patients did not finish treatment. There was no difference in completion of treatment between patients living in Katete district finishing treatment vs. living outside Katete district (respectively 25% vs. 32%, P = 0.7148).

CONCLUSION

There is potential for higher cure rates for BL in tropical settings if full effort is put into compliance since a majority of patients, even while having a good prognosis, abandon treatment. Large distance to hospital makes no difference in completing the chemotherapy course.

The genotype 3-specific hepatitis C virus core protein residue phenylalanine 164 increases steatosis in an in vitro cellular model

BACKGROUND AND AIMS

The prevalence and severity of liver steatosis are higher in patients infected with genotype 3 hepatitis C virus (HCV) than in patients infected with other genotypes. HCV core protein is known to affect lipid metabolism, inducing lipid droplet accumulation both in vitro and in vivo. An in vitro cellular model was used to investigate whether an HCV core protein with residues specific to genotype 3 increased this phenomenon.

METHODS

Sequence comparisons for HCV core protein domain II, which is known to interact with lipid droplets, identified the phenylalanine (F) residue at position 164 as the only residue specific to genotype 3. The area covered by lipid droplets in sections of cells producing a wild-type genotype 1a HCV core protein was compared with that in cells producing a Y164F mutant protein.

RESULTS

Cumulative lipid droplet area was significantly greater in sections of cells producing the Y164F mutant HCV core protein than in cells producing the wild-type protein (p<0.001). The frequency of cell sections containing more than 3 mum(2) of lipid droplets, in particular, was higher for the mutant than for the wild-type protein.

CONCLUSION

The data provide a molecular explanation for HCV genotype 3-specific lipid accumulation. This difference between genotypes may be due to phenylalanine having a higher affinity for lipids than tyrosine (Y). These observations provide useful information for further studies of the mechanisms involved in HCV-induced steatosis.

AL amyloidosis associated with B-cell lymphoproliferative disorders: frequency and treatment outcomes

AL amyloidosis, a systemic disorder characterized by widespread deposition of amyloid fibrils derived from monoclonal Ig light chains in organs and soft tissues, is typically caused by an underlying plasma cell dyscrasia. However, this disease can also be associated rarely with a B-cell lymphoproliferative disorder. In this report, we describe the presentation and clinical course of 16 patients with this association. Although amyloid-related organ involvement in these patients was typical of AL amyloidosis, the patients in this series were on average older and more likely to be female than patients with disease associated with a plasma cell dyscrasia. They were also more likely to have multisystem involvement. Treatment decisions were based primarily on the dominent hematopathologic features of the associated lymphoproliferative disorder. However, high-dose melphalan and stem cell transplantation was the primary therapy in 5 patients, and each of these patients had prolonged survival, ranging from 36 to 102 months.

Altered crossbridge kinetics in the alphaMHC403/+ mouse model of familial hypertrophic cardiomyopathy

A mutation in the cardiac beta-myosin heavy chain, Arg403Gln (R403Q), causes a severe form of familial hypertrophic cardiomyopathy (FHC) in humans. We used small-amplitude (0.25%) length-perturbation analysis to examine the mechanical properties of skinned left ventricular papillary muscle strips from mouse hearts bearing the R403Q mutation in the alpha-myosin heavy chain (alphaMHC403/+). Myofibrillar disarray with variable penetrance occurred in the left ventricular free wall of the alphaMHC403/+ hearts. In resting strips (pCa 8), dynamic stiffness was approximately 40% greater than in wild-type strips, consistent with elevated diastolic stiffness reported for murine hearts with FHC. At pCa 6 (submaximal activation), strip isometric tension was approximately 3 times higher than for wild-type strips, whereas at pCa 5 (maximal activation), tension was marginally lower. At submaximal calcium activation the characteristic frequencies of the work-producing (b) and work-absorbing (c) steps of the crossbridge were less in alphaMHC403/+ strips than in wild-type strips (b=11+/-1 versus 15+/-1 Hz; c= 58+/-3 versus 66+/-3 Hz; 27 degrees C). At maximal calcium activation, strip oscillatory power was reduced (0. 53+/-0.25 versus 1.03+/-0.18 mW/mm3; 27 degrees C), which is partly attributable to the reduced frequency b, at which crossbridge work is maximum. The results are consistent with the hypothesis that the R403Q mutation reduces the strong binding affinity of myosin for actin. Myosin heads may accumulate in a preforce state that promotes cooperative activation of the thin filament at submaximal calcium but blunts maximal tension and oscillatory power output at maximal calcium. The calcium-dependent effect of the mutation (whether facilitating or debilitating), together with a variable degree of fibrosis and myofibrillar disorder, may contribute to the diversity of clinical symptoms observed in murine FHC.

Energetic aspects of inotropic interventions in rat myocardium

Contractile force of the myocardium can be increased by different molecular mechanisms, and therefore different energetic consequences may result. The influence of the inotropic substances isoproterenol and UDCG-115 on myocardial energetics in isometrically contracting left ventricular rat papillary muscles was investigated by means of highly sensitive antimony bismuth thermopiles. Isoproterenol increased total heat and initial heat by 147% (p less than 0.01) and 69% (p less than 0.02) when normalized to tension-time integral, respectively. No significant change of both heat terms occurred due to UDCG-115. Initial heat was separated into tension-independent heat ("calcium cycling") and tension-dependent heat ("cross-bridge cycling") by means of a new method using 2,3-butanedione monoxime. Both tension-dependent heat per tension-time integral and tension-independent heat increased significantly, due to isoproterenol, from 4.9 +/- 1.17 to 7.6 +/- 2.72 mu cal/g.cm.s (p less than 0.05) and from 0.15 +/- 0.06 to 0.22 +/- 0.04 mcal/g (p less than 0.01). UDCG-115 influenced neither tension-independent heat nor tension-dependent heat per tension-time integral significantly. Thus, the economy of force development was not significantly altered due to UDCG-115 whereas isoproterenol significantly increased the energy necessary for activation, i.e. calcium cycling, and the energy necessary for force production, i.e. cross-bridge cycling. The basic mechanisms of these energetic changes are discussed.

Myothermal economy of rat myocardium, chronic adaptation versus acute inotropism

By means of rapid planar Hill type antimony-bismuth thermophiles the initial heat liberated by papillary muscles was measured synchronously with developed tension for control (C), pressure-overload (GOP), and hypothyrotic (PTU) rat myocardium (chronic experiments) and after application of 10(-6) M isoproterenol or 200 10(-6) M UDCG-115. Economy of force production was analyzed by the ratio of initial heat versus developed tension-time integral. This ratio was found to be reduced by 34% in GOP and by 43% in PTU myocardium (P less than 0.01, respectively) indicating increased economy of force production. In contrast, isoproterenol increased initial heat versus tension-time integral by 70% (P less than 0.01) indicating reduced economy of force production. No change in this ratio was found for UDCG-115. The presented data indicates that long and short term modulation of myocardial energetic costs of force generation is possible. The basic mechanisms for these myocardial alterations are discussed.

The use of feedback training and a stimulus control procedure to obtain large magnitude increases in heart rate outside of the laboratory

A series of eight single-subject experiments were performed to test the feasibility of using a stimulus control procedure to teach subjects to control heart rate in the absence of feedback and outside of the laboratory. Four of the six subjects who completed the experiments were able to demonstrate increases in heart rate of from 15 to 35 beats per minute without the assistance of feedback and outside of the laboratory. These increases were consistently produced over six daily sesssions. Through the use of a systematic replication series of experiments, it was possible tentatively to rule out age, sex, and basal heart rate of subject, as well as type of previous feedback training and number of prior training sessions, as accounting for the differential success.