Synthetic strands of neonatal mouse cardiac myocytes: structural and electrophysiological properties.

The aim of the present study was to morphologically and electrically characterize synthetic strands of mouse ventricular myocytes. Linear strands of mouse ventricular myocytes with widths of 34.7+/-4.4 microm (W(1)), 57.9+/-2.5 microm (W(2)), and 86.4+/-3. 6 microm (W(3)) and a length of 10 mm were produced on glass coverslips with a photolithographic technique. Action potentials (APs) were measured from individual cells within the strands with cell-attached microelectrodes. Impulse propagation and AP upstrokes were measured with multisite optical mapping (RH237). Immunostaining was performed to assess cell-cell connections and myofibril arrangement with polyclonal antisera against connexin43 and N-cadherins and monoclonal antibodies against cardiac myosin. Light microscopy and myosin staining showed dense growth of well-developed elongated myocytes with lengths of 34.2+/-4.2 microm (W(1)), 36. 9+/-5.8 microm (W(2)), and 43.7+/-6.9 microm (W(3)), and length/width ratios of 3.9+/-0.2. Gap junctions were distributed around the cell borders (3 to 4 junctions/microm(2) cell area). Each cell was connected by gap junctions to 6.5+/-1.1 neighboring cells. AP duration shortened with time in culture (action potential duration at 50% repolarization: day 4, 103+/-34 ms; day 8, 16+/-3 ms; P:<0.01). Minimum diastolic potential and AP amplitude were 71+/-5 and 97.2+/-7.6 mV, respectively. Conduction velocity and the maximum dV/dt of the AP upstroke were 43.9+/-13.6 cm/s and 196+/-67 V/s, respectively. Thus, neonatal ventricular mouse myocytes can be grown in continuous synthetic strands. Gap junction distribution is similar to the neonatal pattern observed in the hearts of larger mammals. Conduction velocity is in the range observed in adult mice and in the higher range for mammalian species probably due to the higher dV/dt(max). This technique will permit the study of propagation, AP, and structure-function relations at cellular resolution in genetically modified mice.

Tachycardia-induced cardiomyopathy in a young Boxer dog with supraventricular tachycardia due to an accessory pathway.

A 1-year-old male Boxer dog presented with sustained supraventricular tachycardia and tachycardia-induced cardiomyopathy. Conversion to sinus rhythm was achieved initially with intravenous lignocaine and subsequently with oral procainamide. Oral procainamide treatment was relatively successful in maintaining normal sinus rhythm with no side effects apart from a reversible change in coat colour. Electrophysiological studies demonstrated the presence of an accessory pathway connecting the right atrium to the right ventricle and confirmed the diagnosis of orthodromic atrioventricular reciprocating tachycardia. Radiofrequency catheter ablation of the accessory pathway led to permanent resolution of the supraventricular tachycardia and for 9.5 years the dog has had no further signs of cardiac disease. The successful treatment of this condition highlights the importance of differentiating tachycardia-induced cardiomyopathy from dilated cardiomyopathy.

Mechanism, localization and cure of atrial arrhythmias occurring after a new intraoperative endocardial radiofrequency ablation procedure for atrial fibrillation.

OBJECTIVES: The purpose of this study was to test a new pattern of radiofrequency ablation for atrial fibrillation (AFib) intended to optimize atrial activation, and to demonstrate the usefulness of catheter techniques for mapping and ablation of postoperative atrial arrhythmias. BACKGROUND: Linear radiofrequency lesions have been used to cure AFib, but the optimal pattern of lesions is unknown and postoperative tachyarrhythmias are common. METHODS: A radial pattern of linear radiofrequency lesions (Star) was made using an endocardial open surgical approach in 25 patients. Postoperative arrhythmias were induced and characterized during electrophysiological studies in 15 patients. RESULTS: The AFib was abolished in most patients (91%), but atrial flutter (AFlut) occurred in 96% of patients postoperatively. At postoperative electrophysiological studies, 37 flutter morphologies were studied in 15 patients (46% spontaneous, cycle length [CL] 223 +/- 25 ms). Seven mechanisms (lesions discontinuity, n = 6; focal mechanism, n = 1) of AFlut were characterized in six patients. In these cases, flutter was abolished using further catheter radiofrequency ablation. In the remaining cases, flutter was usually localized to an area involving the interatrial septum, but no critical isthmus was identified for ablation. After 16 +/-10 months, 15 patients (65%) were asymptomatic with (n = 3) or without (n = 12) antiarrhythmic medications. Eight (35%) patients had persistent arrhythmias. Postoperative atrial electrical activation was near physiological. CONCLUSIONS: The AFib maybe abolished using a radial pattern of linear endocardial radiofrequency lesions, but postoperative AFlut is common even when lesions are made under optimal conditions. Endocardial mapping techniques can be used to characterize the flutter mechanisms, thus enabling subsequent successful catheter ablation.

Potential ototoxicity from triamcinolone, neomycin, gramicidin and nystatin (Tri-Adcortyl) cream.

Although rare, ototoxicity from the use of aminoglycoside drops is well recognized. Ototoxicity has not been described with the use of combination aminoglycoside-steroid-antifungal creams or ointments. We present the case of a 60-year-old man with a perforated tympanic membrane who suffered a total hearing loss after the instillation of cream containing triamcinolone, neomycin, gramicidin and nystatin (Tri-Adcortyl cream) into his ear canal. On balance, we believe that a number of potentially ototoxic constituents in this cream were responsible. Other possible causes of sensorineural hearing loss and the possible mechanisms of ototoxicity of this cream are discussed. The reasons why such creams may be particularly ototoxic, compared with drops, are also considered. The authors caution against the use of such creams or ointments in the ear if there is any suspicion of a tympanic membrane perforation.

Devastating injuries in healthcare workers: description of the crisis and legislative solution to the epidemic of back injury from patient lifting.

The purpose of this report is to describe a crisis in healthcare, disabling back injuries in US healthcare workers. In addition, outlined is the proven solution of safe, mechanized, patient lifting, which has been shown to prevent these injuries. A "Safe Patient Handling--No Manual Lift" policy must be immediately instituted throughout this country. Such a policy is essential to halt hazardous manual patient lifting, which promotes needless disability and loss of healthcare workers, pain and risk of severe injury to patients, and tremendous waste of financial resources to employers and workers' compensation insurance carriers. Healthcare workers consistently rank among top occupations with disabling back injuries, primarily from manually lifting patients. Back injury may be the single largest contributor to the nursing shortage. Reported injuries to certified nursing assistants are three to four times that of registered nurses. A national healthcare policy for "Safe Patient Handling--No Manual Lift" is urgently needed to address this crisis. Body mechanics training is ineffective in prevention of back injury with patient lifting. Mandated use of mechanical patient lift equipment has proven to prevent most back injury to nursing personnel and reduce pain and injury to patients associated with manual lifting. With the national epidemic of morbid obesity in our country, innovative devices are available for use in emergency medical systems and hospitals for patient lifting and transfer without injury to hospital personnel. The US healthcare industry has not voluntarily taken measures necessary to reduce patient handling injury by use of mechanical lift devices. US healthcare workers who suffer disabling work-related back injuries are limited to the fixed, and often inadequate, relief which they may obtain from workers' compensation. Under workers' compensation law, healthcare workers injured lifting patients may not sue their employer for not providing mechanical lift equipment. Discarding healthcare workers disabled by preventable back injuries is an abuse which legislators must remedy. In addition, Medicare reimbursement policies must also be updated to allow the disabled community to purchase electrically operated overhead ceiling lifts. The US lags far behind countries with legislated manual handling regulations and "No Lifting" nursing policies. England and Australia have had "No Lifting" nursing policies in place since 1996 and 1998, respectively. The National Occupational Research Agenda (NORA) recognized a model in 2003 for reduction of back injuries to nursing staff in US healthcare facilities. Also in 2003, the American Nurses Association called for elimination of manual patient handling because it is unsafe and causes musculoskeletal injuries to nurses. The first state legislation for safe patient handling passed both houses in California but was vetoed by the Governor in September 2004. California and other states are preparing to (re)introduce legislation in January 2005. A national, industry-specific policy is essential to quell the outflow of nursing personnel to disability from manual patient lifting.

Radiofrequency lesions produced by handheld temperature controlled probes for use in atrial fibrillation surgery.

OBJECTIVES: Detailed analysis of the size and shape of lesions produced by handheld radiofrequency ablation devices at open heart surgery has not been reported previously. METHODS: Radiofrequency lesions were made from the epicardial surface of the cardiac ventricles in open-chested dogs. The effects of electrode size, electrode temperature and duration of ablation were studied. In a second group of experiments simultaneous multielectrode ablation was performed on the ventricular epicardium after cold cardioplegia. RESULTS: Using a single 12 x 2.5 mm electrode and a target temperature of 80 degrees C the lesion depth increased from 3.8+/-0.9 mm at 15 s, to 6.1+/-0.9 mm at 120 s (P=0.01). Increasing the target temperature from 70 to 90 degrees C (for 60 s) increased lesion depth from 5.0+/-1.2 to 5.6+/-1.7 mm (P=0.2). There was no difference in depth of lesions with the two electrode widths (4.0+/-0.5 mm (large) vs. 3.9+/-1.0 mm (small)). Lesions produced using the multielectrode probe (80 degrees C, 60 s) were 30-35 mm long with even penetration into the tissue. The mean depth of these lesions on microscopic sections was 3.9 mm. The mean width was 7.1 mm. CONCLUSIONS: Handheld probes can be used to make deep linear lesions in the myocardium. Lesions expand rapidly and are wider than they are deep. A multielectrode ablation device allows rapid formation of linear lesions.

Induction of atrial fibrillation and flutter in dogs using methacholine.

Systemic infusion of methacholine has been used to facilitate induction of atrial fibrillation. However, the dose-response relationship, reproducibility and effect of anesthetic agents on induction are not well understood. The use of methacholine to facilitate electrical induction of sustained (>10 minutes duration) atrial fibrillation or flutter was examined. In 25 dogs induction of atrial arrhythmias was attempted using a series of ten 50 Hz trains of 10 seconds duration delivered via an endocardial catheter in the baseline anaesthetized state and subsequently in the presence of graded doses of intravenous methacholine (maximum 5 microg/kg/min). Studies were repeated in 13 dogs to assess reproducibility. Twelve dogs (48%) had inducible sustained atrial flutter or fibrillation lasting greater than 10 minutes in the baseline state. During infusion of methacholine the remaining 13 (52%) dogs also had inducible sustained atrial flutter or fibrillation (mean infusion rate 1.6 +/- 1.9 microg/kg/min). Induction of sustained atrial flutter or fibrillation was reproducible in all but one dog. The type of anesthetic did not significantly affect inducibility. Induction of prolonged atrial fibrillation or flutter is possible in the baseline anaesthetized state in approximately half of dogs using high frequency programmed electrical stimulation. The yield of inducible sustained atrial fibrillation or flutter with programmed stimulation during intravenous infusion of methacholine was increased to 100%. Induction of sustained atrial fibrillation or flutter was highly reproducible.

The effect of a residual isthmus of surviving tissue on conduction after linear ablation in atrial myocardium.

The aim of this study was to determine the relationship between the size of discontinuities in lines of ablation and wavefront propagation. Discontinuities in linear radiofrequency lesions used for the treatment of atrial fibrillation may be proarrhythmic and a major clinical problem. A better understanding of the electrophysiological properties of these discontinuities (isthmuses) may assist in their detection and treatment. Linear lesions were made in the right atrial free wall using a Nd:YAG laser in 12 dogs. Conduction properties across the discontinuities were studied by pacing from either side of the lesion. Two of the three isthmuses less than 0.8 mm(2) in cross section (smallest 0.2 mm(2)) conducted at extrastimulus intervals of 300 ms. All three failed to conduct at cycle lengths close to the atrial effective refractory period. Isthmuses above 0.8 mm(2) (n¿=8) conducted at all cycle lengths. Conduction slowing (mean slowest conduction 0.5 +/- 0.3 m/s) occurred in the region of the isthmus but the overall delay was only 6 +/- 6 ms where propagation through the isthmus occurred. The effect on conduction of small discontinuities in linear lesions is dependent on the size of the residual isthmus. All but the very smallest of discontinuities in linear lesions conduct and therefore have the potential to participate in reentrant arrhythmias. Efforts should be directed toward the development of ablation techniques that reliably produce continuous transmural linear lesions for cure of atrial fibrillation and flutter.

Correlates of anger symptoms in women in middle adulthood.

BACKGROUND: Anger is of great interest to health professionals due to its relationship with disease outcomes. However, male samples have been used in most studies examining linkages between anger and health indicators. In this exploratory study, anger symptoms and their cognitive and environmental correlates were examined in a sample of 87 women in middle adulthood. METHODS: This descriptive-correlational study involved secondary analyses of data obtained in the third phase of a longitudinal study of health in middle adulthood. Data were collected with a battery of well-established self-report instruments. Descriptive statistics, t tests, and correlational and regression analysis were used. RESULTS: Significant correlates of anger symptoms included lower optimism, external health locus of control, higher frequency and severity of daily hassles, lower functional social support, and loss of important relationship(s) during the past year. Greater body mass index, inadequate sleep, lack of exercise, drinking, and use of over-the-counter drugs were also associated with anger symptomatology. DISCUSSION: Findings regarding the relationship of daily stress and anger were consistent with the Framingham Study. Contrary to expectations, women who reported more anger symptoms were not suppressors of their anger but directed it outward.

Chemical and biological effects of acid, aluminium and lime additions to a Welsh Hill-stream.

Chemical and biological responses to simultaneous additions of acid, aluminium and lime were investigated in contiguous 250m-reaches of a chronically acidic stream in Wales. Treatments were applied for 24 h, and from the upstream end were as follows: zone A-untreated, pH 5.0, 0.37 mg litre(-1) filterable Al; zone B-acidified to pH 4.5, 0.40 mg Al litre(-1) (47% of Al attributed to release from the stream bed due to acid additions); zone C-acidified to pH 4.5 and Al dosed to 0.67 mg litre(-1); zone D-dosed with limestone slurry, resulting in pH 7.2, 0.13 mg Al litre(-1). In all reaches, the chemistry of the interstitial water at depths of 0.15 and 0.3 m never fell below pH 5.5, with corresponding decreases in Al and increases in base cation concentrations. Brown trout, Salmo trutta, and crayfish, Austropotamobius pallipes, held in the stream showed decreases in plasma [Na(+)] and haemolymph [Na(+)], respectively, in all acidic zones (A, B, C): these responses were mitigated by liming (zone D). Thus both chronic and simulated episodic levels of pH and dissolved Al were sub-lethally toxic to test species of aquatic fauna. This experiment also demonstrates a stream bed source/sink of Al, and the availability of a possible refuge from acidic surface waters within the substratum.

Anger and cancer: an analysis of the linkages.

The purposes of this article are to review literature on anger's link to cancer, to analyze the state of the science in this area, and to propose some directions for future research. Extremely low anger scores have been noted in numerous studies of patients with cancer. Such low scores suggest suppression, repression, or restraint of anger. There is evidence to show that suppressed anger can be a precursor to the development of cancer, and also a factor in its progression after diagnosis. Some studies indicate that it may be beneficial for patients to mobilize anger to battle their cancer. However, there is a paucity of research on the outcomes of various anger interventions. Longitudinal studies that repeatedly measure anger and other moods over the disease trajectory are needed.

Extrapunitive and intropunitive anger of HIV caregivers: nursing implications.

The purpose of this qualitative study was to investigate the anger of individuals who have provided direct patient care to loved ones who are living with or who have died from AIDS. The sample consisted of eight individuals who are currently involved in an AIDS service organization in northeast Tennessee. Data were collected using semistructured taped interviews. At the beginning of the study, two group interviews were conducted. Subsequently, each of the participants was interviewed privately. Extrapunitive and intropunitive anger were predominant themes in each of the interviews. Participants also reported ways of coping with their anger. Nurses can suggest these strategies to other caregivers who are experiencing anger. Recommendations for additional nursing interventions are offered.

A phenomenologic study of chronic pain.

Researchers have seldom invited patients with chronic pain to describe their lived experiences. This phenomenologic study involved in-depth interviews with nine women and four men with nonmalignant chronic pain. The essence of participants' experiences was unremitting torment by a force or monster that cannot be tamed. The body was altered and recalcitrant, the life world was shrunken, and the pain set up a barrier that separated them from other people. Time seemed to stop; the future was unfathomable. Findings of this study contribute to the phenomenological literature that explores the human body and its symbolic meanings and call into question the idealized positive depiction of chronic illness that is prominent in contemporary literature.

A theory-based nursing intervention to instill hope in homeless veterans.

This quasi-experimental study sought to determine if a specific nursing intervention to instill hope would positively influence levels of hope, self-efficacy, self-esteem, and depression in homeless veterans. Miller's Model of Patient Power Resources served as the conceptual framework from which a middle-range theory of homelessness-hopelessness was derived to guide the study. Homeless veterans completed pretests on admission to a Veterans Affairs Medical Center, were randomly assigned to treatment or waiting control group, and completed posttests at the end of 4 weeks. There was support for the homelessness-hopelessness theory as evidenced by a high level of depression and low levels of hope, self-efficacy, and self-esteem among these homeless veterans. Further support for the theory was seen in the increased levels of hope and self-esteem and decreased depression in veterans who received the nursing intervention. Treatment and control groups differed significantly with regard to hope at posttest.

Issues in data management and storage.

Safeguarding the integrity of the scientific enterprise involves many elements. In this article, issues related to proper management and storage of data have been explored. Such issues have assumed increased prominence in the biomedical research community in the wake of new PHS regulations. Guidelines were proposed to assist nurse researchers, and a national data archive has been recommended for the future.

Living with postpartum depression: the father's experience.

PURPOSE: To derive a deeper understanding of postpartum depression (PPD) and its impact on the family through the experiences of fathers whose spouses suffered from this disorder. DESIGN: Phenomenology. METHODS: Eight men were interviewed. Interviews were recorded on audio tape and transcribed verbatim. Thematic analysis conducted within an interdisciplinary phenomenological research group led to a description of the experiences and emotions involved. RESULTS: Respondents in this study revealed a major disruption in their lives and in their relationship with their wives as a result of PPD. The men experienced fear, confusion, and much concern for their spouses, and felt unable to help them in overcoming PPD. The inability to "fix the problem" created frustration and anger. The majority of the respondents reported that they made many sacrifices to hold the relationship and the family together. Even though the PPD improved over time, fathers were left to face an uncertain future with a spouse who seemed to be very different from the person they had previously known. CLINICAL IMPLICATIONS: Health care professionals need to design interventions that are more supportive of men, for men also suffer when their spouses experience PPD.

Assessing and intervening with anger disorders.

Nurses often find angry patients threatening. In this article, current research will be synthesized to provide guidance to nurses whose specialty area may not be psychiatric nursing. Guidelines for assessing and intervening with angry clients will be provided. Such guidelines are likely to be useful to nurses in every clinical setting, from the emergency room to the rural clinic to the high-tech hospital unit. Nurses will also learn some techniques for managing their own anger at uncooperative or hostile clients.

Continuity and discontinuity: the quality of life following stroke.

The purpose of this existential-phenomenological study was to investigate the experience of life after stroke rehabilitation, to provide a holistic view for nurses and others in providing care. Analysis involved a part-to-whole dialectic; selected transcripts, including the bracketing interview, were analyzed in an interpretive research group. There were 14 participants, with a 2-year median length of time since stroke; participants exhibited various disabilities. The world of the stroke survivor is grounded in a life of loss and effort from which emerged interrelated themes: independence/dependence, in control/out of control, and connection/disconnection with others. A fundamental aspect of these themes is a sense of continuity that coexists with discontinuity in the experience of self. The findings have implications for how nurses interact with stroke survivors, for goal-setting, and for specific strategies that focus on meanings for clients.

Teaching healthy anger management.

TOPIC: Teaching anger management in the community. PURPOSE: To describe anger management and offer guidelines for assessing potential participants and teaching healthy behaviors. SOURCES: Drawing from the literature, more than 10 years of quantitative and qualitative studies by our research team, and 5 years of experience in conducting anger management groups, the author presents basic principles of teaching anger management. A model is described for a 4-week group for women. CONCLUSIONS: Anger management has wide applicability to a variety of constituencies for both primary and secondary prevention. Advanced practice psychiatric nurses are well-qualified to provide this psychoeducational intervention.

The view from Scutari: a look at contemporary nursing.

Modern nursing and healthcare delivery are examined from a unique vantage point provided by the author's visit to Scutari, Turkey. In Selimiye Army Barracks at Scutari, Florence Nightingale lived while directing the care of thousands of wounded British soldiers during the Crimean War. What was Nightingale's legacy to nursing, and what have nurses done with it? If Miss Nightingale were at her desk reading a status report on 20th-century nursing, what reactions would she have? What wars are engaging contemporary nursing? The author contends that Nightingale's vision can inspire us to move forward as a profession.