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Despite its common use in nonmyeloablative preparative regimens, the pharmacokinetics of fludarabine are poorly characterized in hematopoietic cell transplantation (HCT) recipients and exposure-response relationships remain undefined. The objective of this study was to evaluate the association between plasma F-ara-A exposure, the systemically circulating moiety of fludarabine, and engraftment, acute GVHD, TRM and OS after HCT. The preparative regimen consisted of CY 50 mg/kg/day i.v. day -6; plus fludarabine 30-40 mg/m²/day i.v. on days -6 to -2 and TBI 200 cGy on day -1. F-ara-A pharmacokinetics were carried out with the first dose of fludarabine in 87 adult patients. Median (range) F-ara-A area-under-the-curve (AUC((0-∞))) was 5.0 μg h/mL (2.0-11.0), clearance 15.3 L/h (6.2-36.6), C(min) 55 ng/mL (17-166) and concentration on day(zero) 16.0 ng/mL (0.1-144.1). Despite dose reductions, patients with renal insufficiency had higher F-ara-A exposures. There was strong association between high plasma concentrations of F-ara-A and increased risk of TRM and reduced OS. Patients with an AUC((0-∞)) greater than 6.5 μg h/mL had 4.56 greater risk of TRM and significantly lower OS. These data suggest that clinical strategies are needed to optimize dosing of fludarabine to prevent overexposure and toxicity in HCT.

The authors investigated the pharmacokinetics of mycophenolic acid over 1 year in 8 Caucasian women undergoing islet cell transplantation. Total mycophenolic acid AUC(0-12) mcg x h/mL before day 60 was 62.1-67.8, declining to 33.6-64.7 thereafter (P = .61). Median total trough concentrations were 1.16-2.90 mcg/mL. Unbound AUC(0-12) was 412-673 ng x h/mL and did not change over time (P = .30). Median percent unbound mycophenolic acid was 0.95% of total concentrations. Individual unbound and total mycophenolic acid concentrations were highly correlated (r2 = 0.94). Total mycophenolic acid trough concentration and total AUC(0-12) were modestly correlated (r2 = 0.65). Intra- and interpatient variability of systemic mycophenolic acid exposure was high. Six patients required dose reductions prior to day 60 due to adverse effects. All subjects achieved insulin independence; 3 later lost graft function. The trend toward higher exposure in the early periods followed by dose reductions suggests that lower initial doses and therapeutic drug monitoring may be necessary. [ABSTRACT FROM AUTHOR]

Background: Hypertensive disorders of pregnancy (HDP) remain a leading cause of maternal morbidity and mortality worldwide, with implications for maternal and neonatal well-being in the short term and for long-term maternal cardiovascular health. Although the mechanisms behind HDP remain incompletely understood, evidence suggests that preeclampsia in particular is a syndrome with more than one distinct subtype., Objectives: The PEACH (PreEclampsia, Angiogenesis, Cardiac dysfunction, Hypertension) Study was established to identify new HDP subtyping systems reflecting aetiology and prognosis and to find markers of later cardiovascular disease risk associated with preeclampsia., Population: The PEACH Study recruited pregnant women referred to two Copenhagen-area hospitals with suspected preeclampsia (mean gestational age at enrolment: 36.7 weeks) and a group of frequency-matched pregnant women planning delivery at the same hospitals and healthy when enrolled mid-pregnancy., Design: Prospective, longitudinal pregnancy cohort., Methods: Participants underwent repeated third-trimester blood sample collection, longitudinal cardiac function assessments using the USCOM-1A during the third trimester and at 1 year postpartum and collection of placental samples immediately after delivery. Medical information was abstracted from medical records and hospital databases., Preliminary Results: During 2016-2018, we recruited 1149 pregnant women, of whom 1101 were followed to delivery. Among 691 women enrolled with suspected preeclampsia, 310 and 172 developed preeclampsia and gestational hypertension respectively. Among 410 women with healthy pregnancies when enrolled mid-pregnancy, 37 later developed hypertensive disorders of pregnancy. Of 1089 women still in the cohort 1 year postpartum, 578 (53.1%) participated in the follow-up assessment., Conclusions: The PEACH Study's rich data from women with and without HDP will enable us to identify new, clinically useful HDP subtypes to aid in decision-making regarding monitoring and treatment. Continued postpartum follow-up will help us develop algorithms to identify women at risk of persistent postpartum cardiac dysfunction and later cardiovascular disease after pregnancies complicated by HDP., (© 2022 The Authors. Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd.)

The American Society for Parenteral and Enteral Nutrition (ASPEN) Position Paper focus is on applying the 4 ethical principles for clinician's decision-making in the use of artificially administered nutrition and hydration (AANH) for adult and pediatric patients. These basic principles are (1) autonomy, respect the patient's healthcare preferences; (2) beneficence, provide healthcare in the best interest of the patient; (3) nonmaleficence, do no harm; and (4) justice, provide all individuals a fair and appropriate distribution of healthcare resources. Preventing and resolving ethical dilemmas is addressed, with an emphasis on a collaborative, interdisciplinary approach. Optimizing early communication and promoting advance care planning, involving completion of an advance directive, including designation of a surrogate decision-maker, are encouraged. Clinicians achieve respect for autonomy when they incorporate the patient, family, community, country, geographical, and presumed cultural values and religious belief considerations into ethical decision-making for adults and children with a shared decision-making process. These discussions should be guided by the 4 ethical principles. Hospital committees and teams, limited-time trials, clinician obligation with conflicts, and forgoing of AANH are addressed. Specific patient conditions are addressed because of the concern for potential ethical issues: coma, decreased consciousness, and dementia; advanced dementia; cancer; eating disorders; and end-stage disease/terminal illness. Incorporated in the Position Paper are ethical decisions during a pandemic and a legal summary involving ethical issues. International authors presented the similarities and differences within their own country or region and compared them with the US perspective., (© 2021 American Society for Parenteral and Enteral Nutrition.)

Objective: To report the clinical and novel electrophysiological features in a child with POLG-related sensory ataxic neuropathy, dysarthria and ophthalmoparesis (SANDO)., Methods: The proband, a male child of Indian descent, underwent serial systemic and ophthalmological evaluations from birth until 14 years of age. Eye examinations included visual acuity and extraocular movement assessments, fundus photography, spectral domain optical coherence tomography and full-field electroretinography (ERG). Detailed genetic testing was also performed., Results: The child carried a homozygous mutation in POLG (c.911T > G/p.Leu304Arg) and manifested systemic features such as seizures, headaches, areflexia, hypotonia, myopathy and vomiting. The child's distance visual acuity was 0.50 and 0.40 LogMAR in the right and left eyes, respectively. Bilateral ophthalmoplegia and ptosis were observed at 5 years of age. The dark-adapted (DA) ERG responses to 2.29 cd s m -2 and 7.6 cd s m -2 stimuli showed a markedly reduced b/a ratio; an electronegative configuration was noted to a DA 7.6 ERG., Conclusion: This is the first documented case of an electronegative ERG in a POLG-related disorder consistent with generalized rod ON-bipolar dysfunction. The rest of the proband's systemic and ophthalmological features were consistent with SANDO but some features overlapped with other POLG-related disorders such as Alpers-Huttenlocher syndrome and autosomal dominant progressive external ophthalmoplegia demonstrating the wide phenotypic overlap expected due to POLG mutations.

Background: Functional hemodynamic indicators (systolic pressure variation [SPV and SPV%] and pulse pressure variation [PPV%]) are sensitive and specific indicators of fluid responsiveness. It was unknown if these indicators could be accurately measured directly from the bedside monitor., Objective: Determine the accuracy of SPV, SPV%, and PPV% measurements by using a stop-cursor method compared with a digitized analog strip (gold standard)., Methods: A prospective observational study using a convenience sample of 30 adult patients in a medical-surgical intensive care unit who were receiving mechanical ventilation and had no spontaneous breaths during 3 sequential ventilator breaths and had an optimized arterial catheter. The peak and nadir arterial pressure values for a ventilator cycle were simultaneously obtained by using the stop-cursor method on the bedside monitor and a hardcopy strip. The indicators were averaged over 3 breaths, and the difference between methods was calculated., Results: Data were analyzed from 29 patients (1 patient excluded) on assist control ventilation (mean [SD] for tidal volume, 7.5 [2] mL/kg; positive end-expiratory pressure, 7 [4] cm H2O). For SPV, the mean bias was 0.4 (SD, 0.9) mm Hg (95% limits of agreement [LOA], -1.4 to 2.2 mm Hg); for SPV%, 0.3 (SD, 0.9; 95% LOA, -1.5% to 2.1%); for PPV%, 1.0 (SD, 3.3; 95% LOA, -5.5% to 7.5%). In only 1 case (PPV%) was there disagreement on fluid response characterization., Conclusions: Statistically significant small differences in SPV and SPV% were detected. The differences in SPV, SPV%, and PPV% were not clinically significant, suggesting that functional hemodynamic indicators can be obtained accurately with the stop-cursor method.

This study compared the effects of a higher protein supplement manufactured from milk vs. a commercially available higher carbohydrate supplement on serum markers of muscle damage, anaerobic exercise, choice reaction time, and body composition during 2 weekends of vigorous hikes with simulated mountain skirmishes. Thirty-five university students, including Reserve Officers Training Corps cadets and athletes, carried 25% of their body weight (up to 26.4 kg) on Friday, Saturday, and Sunday hikes. Supplementation and Wingate tests followed each hike, and choice reaction testing preceded and followed each hike. Blood samples were obtained and body compositions were measured pre- and postweekend. Increased cortisol, highly sensitive C-reactive protein, creatine phosphokinase, and aldolase suggested the exercise regimen induced muscle damage and inflammation, which was attenuated during the second weekend of hikes. Absolute anaerobic capacity was somewhat greater following consumption of the milk supplement (p = 0.082). Body compositions did not change significantly during this study. Choice reaction times decreased following hikes and were significantly faster following consumption of the carbohydrate supplement (p < 0.04). Supplements including milk proteins and carbohydrates may improve endurance exercise and decision-making abilities of military personnel and endurance athletes.

The Akita mouse is a robust model of diabetic autonomic neuropathy which develops severe diabetes following beta cell death, which occurs reproducibly at 3-4 weeks of age, and maintains the diabetic state without therapy for as long as 11 additional months. Neuritic dystrophy and neuronopathy involving prevertebral sympathetic superior mesenteric and celiac ganglia begin to develop within the first two months of onset of diabetes and are progressive with time. We have examined the effect of insulin implants resulting in normoglycemia and injections of ARA290, a small erythropoietin peptide which has no effect on glycemic parameters, on the reversal of established neuritic dystrophy and neuronopathy. We have found that 4 weeks of insulin therapy beginning at 2 months of diabetes resulted in normalization of blood glucose, body weight and HbA1c. Insulin therapy successfully reversed established neuritic dystrophy and neuronopathy to control levels. Numbers of sympathetic neurons were not significantly changed in either 3 month diabetic or insulin-treated Akita mice. Treatment with ARA290 for 7 weeks beginning at 4 months of diabetes did not result in altered metabolic severity of diabetes as measured by blood glucose, body weight or HbA1c levels. ARA290 treatment was able to decrease neuritic dystrophy by 55-74% compared to untreated diabetics or in comparison to a separate group of diabetic animals representing the 4 month treatment onset point. Surprisingly, there was no effect of ARA290 on ganglionic neuron number or ongoing neuronopathy (pale/degenerating neurons) in diabetic Akita mice during this time period. The development of neuroprotective EPO-like peptides may provide a possible future therapy for this debilitating complication of diabetes; however, it appears that discrete elements may be differentially targeted by the diabetic state and may require selective therapy., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Genetic ablation of calcium-independent phospholipase A(2)gamma (iPLA(2)gamma) results in profound alterations in hippocampal phospholipid metabolism and mitochondrial phospholipid homeostasis resulting in enlarged and degenerating mitochondria leading to autophagy and cognitive dysfunction. Shotgun lipidomics demonstrated multiple alterations in hippocampal lipid metabolism in iPLA(2)gamma(-/-) mice including: 1) a markedly elevated hippocampal cardiolipin content with an altered molecular species composition characterized by a shift to shorter chain length molecular species; 2) alterations in both choline and ethanolamine glycerophospholipids, including a decreased plasmenylethanolamine content; 3) increased oxidized phosphatidylethanolamine molecular species; and 4) an increased content of ceramides. Electron microscopic examination demonstrated the presence of enlarged heteromorphic lamellar structures undergoing degeneration accompanied by the presence of ubiquitin positive spheroid inclusion bodies. Purification of these enlarged heteromorphic lamellar structures by buoyant density centrifugation and subsequent SDS-PAGE and proteomics identified them as degenerating mitochondria. Collectively, these results identify the obligatory role of iPLA(2)gamma in neuronal mitochondrial lipid metabolism and membrane structure demonstrating that iPLA(2)gamma loss of function results in a mitochondrial neurodegenerative disorder characterized by degenerating mitochondria, autophagy, and cognitive dysfunction.

Objective: Awareness of the privileges and limits of one's role as physician, as well as recognition and respect for the patient as a human being, are central to ethical medical practice. The authors were particularly interested in examining the attitudes and perceived needs of psychiatric residents toward education on professional boundaries and relationships given the heightened current focus on professionalism and ethics., Methods: Residents from six psychiatric residencies provided views on professionalism and ethics education on a survey encompassing 10 domains of professionalism. The authors focus on residents' perceived need for education on boundaries in the psychiatrist-patient relationship and in peer-peer and supervisor-trainee interactions., Results: Respondents (N=134) felt that nine relationship and boundary issues arising during training should receive more education: being asked to work with inadequate supervision, resolving conflicts between attendings and trainees, resident health care, adequately caring for patients while adhering to work-hour guidelines, performing work beyond one's competence, mistreatment of residents, sexual/romantic relationships between faculty and trainees, mistreatment of medical students, and sexual/romantic relationships between residents and medical students (p<0.05 in all cases). In addition, 15 relationship and boundary issues arising during clinical practice were felt to warrant more education: responding to impaired colleagues, coping with mistakes in clinical care, reporting mistakes, balancing personal and professional life, resolving conflicts, writing prescriptions for friends or family, allocation of health care resources, providing medical advice to friends and family, physicians' social responsibilities, interacting with families, medicine as a profession, gender bias, being asked to falsify clinical information, accepting gifts from patients, and personal relationships with patients (p<0.05 in all cases)., Conclusion: The authors found a perceived need for more education for psychiatric residents for the majority of topics pertaining to boundaries and relationships. Residents who reported encountering ethical dilemmas more frequently wanted more education on these topics.

Objective: Whether and under what circumstances medical residents seek personal health care is a growing concern that has important implications for medical education and patient welfare, but has not been thoroughly investigated. Barriers to obtaining care have been previously documented, but very little empirical work has focused on trainees who seek health care at their home institution., Methods: A self-report survey on special issues in personal health care of residents was created and distributed at the University of New Mexico School of Medicine in 2001. The authors report findings regarding stigma, fear of jeopardy to training status, and attitudes toward seeking self-care for residents in dual roles as patients and trainees., Results: Residents (N=155) rated their concerns regarding stigma and jeopardy to training status and the likelihood of seeking care at their training institution for six vignettes. The vignettes were paired to make comparisons between attending or supervisor as treating physician and between clinical scenarios. Alcohol abuse, nausea and diarrhea, panic attacks, and pregnancy were the most highly stigmatizing to residents; diabetes and hypertension were the least. Differences were also found for gender and specialty., Conclusion: Residents' perceived stigma for clinical situations was an influential factor, strongly affecting concern about jeopardizing training status and likelihood of avoiding care at their home institution.

Objective: Despite the acknowledged importance of ethics education in medical school, little empirical work has been done to assess the needs and preferences of medical students regarding ethics curricula., Methods: Eighty-three medical students at the University of New Mexico participated in a self-administered written survey including 41 scaled questions regarding attitudes, needs, and preferences toward medical ethics and ethics education., Results: Students reported strong personal interest in learning more about ethics in clinical medicine and research. They most strongly endorsed as valid objectives of ethics education the goals of helping professionals "better recognize ethical issues and clarify values-laden choices," "improve patient care and clinical decision-making," and "improve ethical practices in clinical research." Participants strongly agreed that "professional attitudes and values are an appropriate focus for medical education" and also expressed strong interest in learning more about specific ethical topics and learning methods. Women more strongly endorsed interest in additional ethics education and a preference for increased ethics education than men. Preclinical participants expressed a greater desire for additional training on all ethics topics than clinical students., Conclusion: The medical students surveyed strongly affirmed ethics education in medical school and expressed clear preferences for curricular topics and teaching methods.

There are three types of cell death; apoptosis, necrosis, and autophagy. The possibility that activation of the macroautophagy (autophagy) pathway may increase beta cell death is addressed in this study. Increased autophagy was present in pancreatic islets from Pdx1(+/-) mice with reduced insulin secretion and beta cell mass. Pdx1 expression was reduced in mouse insulinoma 6 (MIN6) cells by delivering small hairpin RNAs using a lentiviral vector. The MIN6 cells died after 7 days of Pdx1 deficiency, and autophagy was evident prior to the onset of cell death. Inhibition of autophagy prolonged cell survival and delayed cell death. Nutrient deprivation increased autophagy in MIN6 cells and mouse and human islets after starvation. Autophagy inhibition partly prevented amino acid starvation-induced MIN6 cell death. The in vivo effects of reduced autophagy were studied by crossing Pdx1(+/-) mice to Becn1(+/-) mice. After 1 week on a high fat diet, 4-week-old Pdx1(+/-) Becn1(+/-) mice showed normal glucose tolerance, preserved beta cell function, and increased beta cell mass compared with Pdx1(+/-) mice. This protective effect of reduced autophagy had worn off after 7 weeks on a high fat diet. Increased autophagy contributes to pancreatic beta cell death in Pdx1 deficiency and following nutrient deprivation. The role of autophagy should be considered in studies of pancreatic beta cell death and diabetes and as a target for novel therapeutic intervention.

Depending on its concentration, nitric oxide (NO) has beneficial or toxic effects. In pathological conditions, NO reacts with superoxide to form peroxynitrite, which nitrates proteins forming nitrotyrosine residues (3NY), leading to loss of protein function, perturbation of signal transduction, and cell death. 3NY immunoreactivity is present in many CNS diseases, particularly multiple sclerosis. Here, using the high flux NO donor, spermine-NONOate, we report that oligodendrocytes are resistant to NO, while motor neurons are NO sensitive. Motor neuron sensitivity correlates with the NO-dependent formation of 3NY, which is significantly more pronounced in motor neurons when compared with oligodendrocytes, suggesting peroxynitrite as the toxic molecule. The heme-metabolizing enzyme, heme-oxygenase-1 (HO1), is necessary for oligodendrocyte NO resistance, as demonstrated by loss of resistance after HO1 inhibition. Resistance is reinstated by peroxynitrite scavenging with uric acid further implicating peroxynitrite as responsible for NO sensitivity. Most importantly, differential sensitivity to NO is also present in cultures of primary oligodendrocytes and motor neurons. Finally, motor neurons cocultured with oligodendrocytes, or oligodendrocyte-conditioned media, become resistant to NO toxicity. Preliminary studies suggest oligodendrocytes release a soluble factor that protects motor neurons. Our findings challenge the current paradigm that oligodendrocytes are the exclusive target of multiple sclerosis pathology.

Diabetic autonomic neuropathy is a debilitating, poorly studied complication of diabetes. Our previous studies of non-obese diabetic (NOD) and related mouse models identified rapidly developing, dramatic pathology in prevertebral sympathetic ganglia; however, once diabetic, the mice did not survive for extended periods needed to examine the ability of therapeutic agents to correct established neuropathy. In the current manuscript we show that the Akita (Ins2(Akita)) mouse is a robust model of diabetic sympathetic autonomic neuropathy with unambiguous, spontaneous, rapidly-developing neuropathology which corresponds closely to the characteristic pathology of other rodent models and man. Akita mice diabetic for 2, 4 or 8 months of diabetes progressively developed markedly swollen axons and dendrites ("neuritic dystrophy") in the prevertebral superior mesenteric (SMG) and celiac ganglia (CG). Comparable changes failed to develop in the superior cervical ganglia (SCG) of the Akita mouse or in any ganglia of non-diabetic mice. Morphometric studies demonstrate an overall increase in presynaptic axon terminal cross sectional area, including those without any ultrastructural features of dystrophy. Neurons in Akita mouse prevertebral sympathetic ganglia show an unusual perikaryal alteration characterized by the accumulation of membranous aggregates and minute mitochondria and loss of rough endoplasmic reticulum. These changes result in the loss of a third of neurons in the CG over the course of 8 months of diabetes. The extended survival of diabetic mice and robust pathologic findings provide a clinically relevant paradigm that will facilitate the analysis of novel therapeutic agents on the reversal of autonomic neuropathy.

Neuroaxonal dystrophy, a distinctive axonopathy characterized by marked enlargement of distal axons, is the hallmark pathologic alteration in aged and diabetic human prevertebral sympathetic ganglia and in corresponding rodent models. Neuroaxonal dystrophy is thought to represent the abnormal outcome of cycles of synaptic degeneration and regeneration; a systematic study of identified axon terminals in aged and diabetic prevertebral ganglia, however, has not previously been performed. We examined the initial changes that develop in presynaptic and postsynaptic elements in sympathetic ganglia of aged and diabetic mice and found numerous synaptic changes involving both presynaptic and postsynaptic elements. Early alterations in presynaptic axon terminal size, vesicle content, and morphology culminate in the development of anastomosing membranous tubulovesicular aggregates, accumulation of autophagosomes, and amorphous debris that form a continuum with progressively larger classically dystrophic swellings. Dendritic changes consist of the development of swellings composed of delicate tubulovesicular elements and mitochondriopathy characterized by increased numbers of small mitochondria and, exclusively in aged ganglia, megamitochondria. These results support the hypothesis that neuroaxonal dystrophy results from progressive changes in presynaptic axon terminals that likely involve membrane dynamics and which are accompanied by distinctive changes in postsynaptic dendritic elements.

The physiologic importance of autophagy proteins for control of mammalian bacterial and parasitic infection in vivo is unknown. Using mice with granulocyte- and macrophage-specific deletion of the essential autophagy protein Atg5, we show that Atg5 is required for in vivo resistance to the intracellular pathogens Listeria monocytogenes and Toxoplasma gondii. In primary macrophages, Atg5 was required for interferongamma (IFN-gamma)/LPS-induced damage to the T. gondii parasitophorous vacuole membrane and parasite clearance. While we did not detect classical hallmarks of autophagy, such as autophagosomes enveloping T. gondii, Atg5 was required for recruitment of IFN-gamma-inducible p47 GTPase IIGP1 (Irga6) to the vacuole membrane, an event that mediates IFN-gamma-mediated clearance of T. gondii. This work shows that Atg5 expression in phagocytic cells is essential for cellular immunity to intracellular pathogens in vivo, and that an autophagy protein can participate in immunity and intracellular killing of pathogens via autophagosome-independent processes such as GTPase trafficking.

Autonomic neuropathy is a significant diabetic complication resulting in increased morbidity and mortality. Studies of autopsied diabetic patients and several rodent models demonstrate that the neuropathologic hallmark of diabetic sympathetic autonomic neuropathy in prevertebral ganglia is the occurrence of synaptic pathology resulting in distinctive dystrophic neurites ("neuritic dystrophy"). Our prior studies show that neuritic dystrophy is reversed by exogenous IGF-I administration without altering the metabolic severity of diabetes, i.e. functioning as a neurotrophic substance. The description of erythropoietin (EPO) synergy with IGF-I function and the recent discovery of EPO's multifaceted neuroprotective role suggested it might substitute for IGF-I in treatment of diabetic autonomic neuropathy. Our current studies demonstrate EPO receptor (EPO-R) mRNA in a cDNA set prepared from NGF-maintained rat sympathetic neuron cultures which decreased with NGF deprivation, a result which demonstrates clearly that sympathetic neurons express EPO-R, a result confirmed by immunohistochemistry. Treatment of STZ-diabetic NOD-SCID mice have demonstrated a dramatic preventative effect of EPO and carbamylated EPO (CEPO, which is neuroprotective but not hematopoietic) on the development of neuritic dystrophy. Neither EPO nor CEPO had a demonstrable effect on the metabolic severity of diabetes. Our results coupled with reported salutary effects of EPO on postural hypotension in a few clinical studies of EPO-treated anemic diabetic and non-diabetic patients may reflect a primary neurotrophic effect of EPO on the sympathetic autonomic nervous system, rather than a primary hematopoietic effect. These findings may represent a major clinical advance since EPO has been widely and safely used in anemic patients due to a variety of clinical conditions.

The American Cancer Society (ACS) has developed guidelines for the use of the prophylactic human papillomavirus (HPV) vaccine for the prevention of cervical intraepithelial neoplasia and cervical cancer. These recommendations are based on a formal review of the available evidence. They address the use of prophylactic HPV vaccines, including who should be vaccinated and at what age, as well as a summary of policy and implementation issues. Implications for screening are also discussed.

Objective: Schizophrenia studies involve diverse procedures with varying levels of risk. Federal regulations indicate that oversight of these protocols entails assessment of risk in relation to the risks encountered in everyday life. No data exist on comparing assessments of people with schizophrenia with those of psychiatrists regarding research procedure risks in relation to the usual risks of living with schizophrenia., Methods: Structured interviews were given to 43 people with schizophrenia and a parallel written survey was given to 68 psychiatrists to compare assessments of relative risk. Twelve research procedures were rated to compare the risk of the procedure with everyday risks. Possible scores range from 1, much less risk, to 3, about the same, to 5, much more risk., Results: People with schizophrenia and psychiatrists viewed filling out questionnaires, drawing a tube of blood, drawing a tube of blood for a genetic test, and having X-rays of the head as being less risky than usual daily risks. Psychiatrists saw showing a word or picture that is upsetting as being less risky than usual daily risks. In contrast, patients saw having a spinal tap, getting a new experimental medication, getting a medication that causes temporary symptoms of schizophrenia, and stopping usual medications for two weeks as being significantly more risky than usual daily risks, but psychiatrists rated only stopping usual medications for two weeks as being more risky than usual daily risks., Conclusions: Substantial congruence exists between patients and psychiatrists regarding their views of research procedure risks. Further work is needed to determine how these assessments may be used in evaluating protocols.

Objective: This study attempted to clarify how people with schizophrenia evaluate the potential harm associated with various research-related procedures and how these assessments relate to participation willingness., Method: The authors conducted a semistructured interview among participants with schizophrenia., Results: Sixty participants with schizophrenia rated four procedures as harmful (e.g., symptom induction), five procedures as moderately harmful (e.g., being given a placebo), and six procedures as not harmful (e.g., undergoing a physical examination). Rated willingness to participate was inversely related to the participants' perceptions of harmfulness for all procedures., Conclusions: In this study, people living with schizophrenia perceived different research procedures as posing different levels of possible harm. Potential harm appears to be an important consideration in protocol enrollment decisions. This work reaffirms the value of clarifying the strengths of seriously ill people who may choose to participate in research.

Objective: To evaluate the effectiveness of a selective serotonin reuptake inhibitor (SSRI) (sertraline) in decreasing hot flashes in a general population of women., Design: A double-blind, placebo-controlled, crossover trial was conducted in a southwestern urban setting. A total of 102 women aged 40 to 65 who were experiencing hot flashes and not taking any hormone therapy were recruited. After 1 week of baseline hot flash data collection, study participants were randomized to receive placebo or active drug (sertraline 50 mg) for 4 weeks. This intervention was followed by a 1-week washout and cross over to the opposite treatment for 4 weeks. The number and severity of hot flashes were measured., Results: One hundred two women were enrolled in the study. Five dropped out before providing baseline data. Of the 97 remaining, 52 were randomized to active drug first and 45 to placebo first. Ten dropped out of the study before completing all 10 weeks, leaving 46 in the active drug-first arm and 41 in the placebo-first arm. At baseline, the mean number of hot flashes reported was 45.6 per week (SD = 29.6), ranging from 2 to 148. During the sertraline phase of the study, women experienced five fewer hot flashes per week than they did on the placebo (P = 0.002). The severity of hot flashes was not significantly different; however, the hot flash score (number x average severity) was significantly improved during the sertraline phase., Conclusion: Sertraline reduced the number of hot flashes and improved the hot flash score relative to placebo and may be an acceptable alternative treatment for women experiencing hot flashes.

Serious mental illness research poses many ethical questions, including important considerations pertaining to how large a study is and its source of funding. Little is known about how people with schizophrenia understand these ethical considerations and whether these factors may influence their decisions to participate in research. Structured interviews were conducted with 60 people with schizophrenia. Participants were asked about levels of suffering and the importance of research for healthy people and for people with serious illnesses. Participants also rated helpfulness and harmfulness to society, and their likelihood of participating in studies involving 10 subjects, 1000 subjects, 1 research institution, or 10 research institutions and in studies funded by various organizations. Participants viewed all types of research positively and indicated willingness to volunteer. Likelihood of participating in research was correlated with perceived helpfulness to society and inversely correlated with perceived harmfulness. Research by pharmaceutical companies was seen as less helpful to society than research sponsored by federal or state government or by private foundations. Larger studies conducted at multiple sites were seen as more helpful to society than smaller studies or those at single sites. Larger studies conducted at single sites, however, were seen as more harmful. Respondents endorsed a positive view of medical research and expressed a willingness to participate in projects of all scales with diverse funding sources. The pattern of responses suggests the capacity for a nuanced understanding of ethically salient aspects of medical research by individuals with schizophrenia.

To define mechanisms regulating expression of cell-cell junction proteins, we have developed an in vitro system in which neonatal rat ventricular myocytes were subjected to pulsatile stretch. Previously, we showed that expression of the gap junction protein, connexin (Cx) 43, is increased by approximately 2-fold after 1 hour of stretch, and this response is mediated by stretch-induced secretion of vascular endothelial growth factor (VEGF). Here, we report that the mechanical junction proteins plakoglobin, desmoplakin, and N-cadherin are also upregulated by pulsatile stretch but by a mechanism independent of VEGF or other secreted chemical signals. Stretch-induced upregulation of mechanical junction proteins was blocked by anti-beta1 and anti-beta3 integrin antibodies. Transfection of cells with adenovirus expressing GFP-FRNK, a dominant-negative inhibitor of focal adhesion kinase (FAK)-dependent signaling, blocked stretch-induced upregulation of Cx43 and mechanical junction proteins but did not block the ability of exogenous VEGF to upregulate Cx43 expression. Conditioned medium removed from uninfected cells after stretch increased Cx43 expression when added to nonstretched cells, and this effect was blocked by anti-VEGF antibodies, but stretch-conditioned medium from GFP-FRNK cells had no effect on Cx43 expression. The src kinase inhibitor 4-amino-5-(4-chloro-phenyl)-7-(t-butyl)pyrazolol[3,4-d]pyrimidine blocked stretch-induced upregulation of mechanical junction proteins but not Cx43. Thus, stretch upregulates expression of both electrical and mechanical junction proteins via integrin-dependent activation of FAK. Stretch-induced upregulation of Cx43 expression is mediated by FAK-dependent secretion of VEGF. In contrast, stretch-induced upregulation of adhesion junction proteins involves intracellular mechanotransduction pathways initiated via integrin signaling and acting downstream of src kinase.

Objective: We studied a transgenic mouse model of human desmin-related cardiomyopathy with cardiac-specific expression of a 7-amino acid deletion mutation in desmin (D7-des) to test the hypothesis that impaired linkage between desmin and desmosomes alters expression and function of the electrical coupling protein, connexin43 (Cx43)., Methods: Expression of Cx43 and selected mechanical junctions proteins was characterized in left ventrices of D7-des and control mice by quantitative confocal microscopy and immunoblotting. Remodeling of gap junctions was also analyzed by electron microscopic morphometry. The electrophysiological phentoype of D7-des mice was characterized by electrocardiography and optical mapping of transmembrane voltage., Results: Cx43 signal at intercalated disks was decreased by approximately 3-fold in D7-des ventricular tissue due to reductions in both gap junction number and size. Immunoreactive signal at cell-cell junctions was also reduced significantly for adhesion molecules and linker proteins of desmosomes and fascia adherens junctions. Electron microscopy showed decreased gap junction remodeling. However, immunoblotting showed that the total tissue content of Cx43 and mechanical junction proteins was not reduced, suggesting that diminished signal at cell-cell junctions was not due to insufficient protein expression, but to failure of these proteins to assemble properly within electrical and mechanical junctions. Remodeling of gap junctions in D7-des mice led to slowing of ventricular conduction as demonstrated by optical electrophysiological mapping., Conclusions: These results illustrate how a defect in a protein conventionally thought to fulfill a mechanical function in the heart can also lead to electrophysiological alterations that may contribute to arrhythmogenesis.

To elucidate mechanisms responsible for mechanotransduction in the heart and define the effects of remodeling of the extracellular matrix, we cultured neonatal rat ventricular myocytes on native type I collagen, fibronectin, or denatured collagen and subjected them to uniaxial, pulsatile stretch. Changes in expression of the cardiac gap junction protein, Cx43, were measured by confocal microscopy and immunoblotting. Cells grown on fibronectin or denatured collagen exhibited significantly greater Cx43 expression than cells grown on native collagen. Stretch induced a approximately 2-fold increase in Cx43 expression in cells grown on native collagen but no increase in cells grown on fibronectin or denatured collagen. Incubation of cells on native collagen with a peptide containing the arginine-glycine-aspartate (RGD) motif upregulated Cx43 expression equivalent to that induced by stretch. Nonselective activation of integrin signaling with MnCl2 also upregulated Cx43 expression in cells grown on native collagen. This effect was blocked completely by pretreatment with anti-beta1 integrin antibody but not by anti-beta3 integrin antibody. Stretch led to a marked increase in beta1 integrin immunofluorescent signal in cells grown on native collagen but not in cells grown on fibronectin or denatured collagen. Stretch-induced upregulation of Cx43 was also blocked by anti-beta1 integrin antibody. Thus, matrix protein-myocyte interactions regulate Cx43 expression via beta1 integrin signaling initiated by mechanical stimulation in cells grown on native type I collagen, or by RGD-integrin signaling independent of mechanical stress in cells grown on fibronectin or denatured collagen. Changes in the composition of the extracellular matrix may affect electrical coupling in cardiac myocytes.

Introduction: Electrophysiologic heterogeneity across the ventricular wall is a result of differential transmural expression of various ion channel proteins that underlie the different action potential waveforms observed in epicardial, midmyocardial, and endocardial regions. Cardiac connexins mediate cell-to-cell communication, are critical for normal impulse propagation, and play a role in electrophysiologic remodeling in disease states. However, little is known about the transmural distribution of cardiac gap junction proteins., Methods and Results: Connexin expression in epicardium, midmyocardium, and endocardium was assessed immunohistochemically in mouse and rat hearts. The total connexin protein content within different ventricular regions was measured by immunoblotting. Connexin43 is twice as abundant in midmyocardium and endocardium compared with epicardium in the mouse but not in the rat. Connexin45 is expressed equally across the left ventricular wall., Conclusion: Epicardial myocytes express significantly less Cx43 and therefore may be less well coupled than midmyocardial and endocardial myocytes. A transmural gradient of connexin43 expression across the left ventricular free wall likely results in differences in the stoichiometry of connexins expressed in different regions of the heart.

Cyclosporine-based immunosuppression is common after allogeneic hematopoietic stem cell transplantation (HSCT). Elevated cyclosporine concentrations are associated with significant toxicity and often result in the temporary cessation or discontinuation of cyclosporine. Low blood concentrations also result in significant immunologic risks, primarily graft-versus-host disease and loss of stem cell graft. The pharmacokinetics of cyclosporine are highly complex, and maintaining therapeutic and safe cyclosporine concentrations are challenging. Several clinical factors are known to independently influence in vivo cyclosporine pharmacokinetic behavior. However, in the critically ill patient, several of these clinical factors are generally present simultaneously. Unfortunately, there are no studies that have evaluated the combined effects of these clinical factors on cyclosporine disposition in HSCT. The objective of our study is to determine the population pharmacokinetic parameters of intravenous and oral cyclosporine, evaluate the effects of clinical covariates on cyclosporine pharmacokinetics, and develop a model that estimates clearance (Cl) and dose requirements for an individual HSCT patient with these clinical covariates. The authors analyzed 740 cyclosporine steady-state whole blood concentrations in 129 adult patients obtained between day 0 and discharge or 60 days posttransplant, whichever came first. Patients received intravenous cyclosporine at 2.5 mg/kg every 12 hours if body weight was greater than 50 kg, 2.5 mg/kg every 8 hours if less than 50 kg, or 5 to 7.5 mg/kg/d given as a continuous infusion, beginning on day-3. Patients were converted to oral therapy as tolerated. The influence of clinical covariates on the Cl of cyclosporine was tested with a nonlinear mixed effects model (NONMEM). The tested clinical covariates were age, height, body weight on admission, body surface area, sex, type of hematologic malignancy, transplant type, preparative regimen, baseline serum creatinine, T-cell depletion of graft, number of methotrexate doses, day of onset, and maximum grade of acute graft-versus-host disease. The route and frequency of cyclosporine administration, day posttransplant, total bilirubin level, serum creatinine level, actual body weight, presence of concurrent CYP450 enzyme inhibitors and inducers, or nephrotoxins on the day of the cyclosporine blood measurement were also evaluated. Cyclosporine Cl significantly decreased each week posttransplant. The authors found no significant effect of any of the other tested covariates including total bilirubin on Cl. The final regression model for the estimation of Cl is: Cl (L/hr) = ([body weight in kg - 70] * 0.183 + 22.3) * (day posttransplant factor). The corresponding day posttransplant factor estimates are 1.46, 1.32, 1.20, and 1.0 during days 0 to 7, 8 to 14, 15 to 21 and greater than 21 posttransplant, respectively. The interindividual variability in Cl was 27.7%. The dose of intravenous or oral cyclosporine can be calculated using the estimated Cl. Understanding cyclosporine pharmacokinetics and the clinical events that lead to alterations in Cl and exposure is critical in optimizing immunosuppressive therapy. The authors found that cyclosporine Cl significantly decreased posttransplant until day 21. A pharmacokinetics model was developed that incorporates the day posttransplant to predict cyclosporine Cl. Cyclosporine dose requirements in an individual HSCT patient to achieve the desired therapeutic blood target can be estimated using this model.

Objective: Adult ventricular myocytes express two gap junction channel proteins: connexin43 (Cx43) and connexin45 (Cx45). Cx43-deficient mice exhibit slow ventricular epicardial conduction, suggesting that Cx43 plays an important role in intercellular coupling in the ventricle. Cx45 is much less abundant than Cx43 in working ventricular myocytes. Its role in ventricular conduction has not been defined, nor is it known whether expression or distribution of Cx45 is altered in Cx43-deficient mice. The present study was undertaken to determine (1) whether expression of Cx45 is upregulated and (2) whether gap junction structure and distribution are altered in Cx43-deficient mice., Methods: Ventricular tissue from neonatal Cx43(+/+), Cx43(+/-) and Cx43(-/-) and adult Cx43(+/+) and Cx43(+/-) mice was analyzed by immunoblotting and confocal immunofluorescence microscopy., Results: Total Cx45 protein abundance measured by immunoblotting was not different in Cx43-deficient or null hearts compared to wild-type control hearts. However, the amount and distribution of Cx45 immunoreactive signal measured by quantitative confocal analysis were markedly reduced in both Cx43(+/-) and Cx43(-/-) hearts., Conclusion: Although the total content of Cx45 is not upregulated in Cx43-deficient hearts, the localization of Cx45 to cardiac gap junctions depends on the expression level of Cx43 and is dramatically altered in mice that express no Cx43.

We tested the hypothesis that cardiac allograft dysfunction in acute cardiac rejection may be related, in part, to diminished expression of connexin43, a gap junction channel protein that facilitates intercellular communication and coordinates electrical and mechanical cardiac function. We measured connexin43 levels using quantitative confocal immunofluorescence microscopy of endocardial biopsies from heart transplant recipients with histologic evidence of either no rejection or acute cellular rejection. Expression of connexin43 diminished significantly during acute cellular rejection and returned to baseline levels following resolution of rejection. Reversible down-regulation of connexin43 may contribute to ventricular dysfunction in allograft rejection.

Gap junction number and size vary widely in cardiac tissues with disparate conduction properties. Little is known about how tissue-specific patterns of intercellular junctions are established and regulated. To elucidate the relationship between gap junction channel protein expression and the structure of gap junctions, we analyzed Cx43 +/- mice, which have a genetic deficiency in expression of the major ventricular gap junction protein, connexin43 (Cx43). Quantitative confocal immunofluorescence microscopy revealed that diminished Cx43 signal in Cx43 +/- mice was due almost entirely to a reduction in the number of individual gap junctions (226 +/- 52 vs. 150 +/- 32 individual gap junctions/field in Cx43 +/+ and +/- ventricles, respectively; P < 0.05). The mean size of an individual gap junction was the same in both groups. Immunofluorescence results were confirmed with electron microscopic morphometry. Thus when connexin expression is diminished, ventricular myocytes become interconnected by a reduced number of large, normally sized gap junctions, rather than a normal number of smaller junctions. Maintenance of large gap junctions may be an adaptive response supporting safe ventricular conduction.

Introduction: Dynamic interplay between active and passive electrical properties of cardiac myocytes is based on interrelationships between various channels responsible for depolarizing and repolarizing ionic currents and intercellular conductances. Mice with targeted disruption of the connexin43 (Cx43) gene have hearts completely devoid of Cx43, the principal gap junctional protein expressed in mammalian hearts., Methods and Results: To determine whether cardiac myocytes that develop in an abnormal environment of reduced intercellular coupling have altered active membrane properties, we studied whole cell action potentials, Na+ channel currents, and Na+ channel expression and distribution via immunoblotting and confocal immunofluorescence in neonatal ventricular myocytes isolated from Cx43 wild-type, heterozygous, and homozygous null hearts. Action potential morphology, peak Na+ current, activation and inactivation kinetics, and Na+ channel protein expression and distribution were not different among myocytes isolated from wild-type, heterozygous, or null hearts. Active membrane properties and Na+ channel activity were completely normal in Cx43-deficient myocytes isolated from hearts that have been shown to exhibit markedly reduced Cx43 expression, gap junction number, and epicardial conduction delay., Conclusion: Despite a genetic inability to produce Cx43 and a developmental history that culminates in marked gross cardiac morphologic abnormalities, premature death, and myocardial inexcitability ex vivo, cardiac Na+ channel distribution and function appear to be normal in Cx43 null hearts. Although intimate structural and functional interrelationships have been described between ion channels and gap junction channels, expression and function of Na+ channels is not affected by the absence of Cx43.

Objectives: To elucidate signal transduction pathways regulating expression of myocardial gap junction channel proteins (connexins) and to determine whether mediators of cardiac hypertrophy might promote remodeling of gap junctions, we characterized the effects of angiotensin II on expression of the major cardiac gap junction protein connexin43 (Cx43) in cultured neonatal rat ventricular myocytes., Background: Remodeling of the distribution of myocardial gap junctions appears to be an important feature of anatomic substrates of ventricular arrhythmias in patients with heart disease. Remodeling of intercellular connections may be initiated by changes in connexin expression caused by chemical mediators of the hypertrophic response., Methods: Cultures were exposed to 0.1 micromol/liter angiotensin II for 6 or 24 h, and Cx43 expression was characterized by immunoblotting, confocal microscopy and electron microscopy., Results: Immunoblot analysis revealed a twofold increase in Cx43 content in cells treated for 24 h with angiotensin II (n=4, p < 0.05). This response was inhibited by the presence of 1.0 micromol/liter losartan, an AT1-receptor blocker. Confocal and electron microscopy demonstrated enhanced Cx43 immunoreactivity and increases in the number and size of gap junction profiles in cells exposed to angiotensin II for 24 h. These effects were also blocked by losartan. Immunoprecipitation of Cx43 from cells metabolically labeled with [35S]methionine demonstrated 2.4- and 2.9-fold increases in Cx43 radioactivity after 6 and 24 h exposure to angiotensin II, respectively (p < 0.03 at each time point)., Conclusions: Angiotensin II up-regulates gap junctions in cultured neonatal rat ventricular myocytes by increasing Cx43 synthesis. Signal transduction pathways activated by angiotensin II under pathophysiologic conditions could initiate remodeling of conduction pathways, leading to the development of anatomic substrates of arrhythmias.

Electrical coupling of pacemaker cells at gap junctions appears to play an important role in sinus node function. Although the major cardiac gap junction protein, connexin43 (Cx43), is expressed abundantly in atrial and ventricular muscle, its expression in the sinus node has been a subject of controversy. The objectives of the present study were to determine whether Cx43 is expressed by sinus node myocytes, to characterize the spectrum of connexin expression phenotypes in sinus node pacemaker cells, and to define the spatial distribution of different connexin phenotypes in the intact sinus node. To fulfill these objectives, we performed high-resolution immunohistochemical analysis of disaggregated adult canine sinus node preparations. Using enhanced tissue preservation and antigen retrieval techniques, we also performed immunohistochemical studies on sections of intact canine sinus node tissue. Analysis of disaggregated sinus node preparations revealed three populations of pacemaker cells distinguished on the basis of connexin immunohistochemical phenotype: approximately 55% of cells expressed only connexin40 (Cx40); 30% to 35% of cells expressed Cx43, connexin45 (Cx45), and Cx40; and the remaining cells had no detectable connexin expression. In immunostained sections of intact sinus node, Cx43- and Cx45-positive cells were limited in their distribution and were observed in discrete bundles that appeared to abut atrial myocytes. In contrast, Cx40 immunoreactive signal was widely distributed in the sinus node region. These results indicate that subsets of pacemaker cells express distinct connexin phenotypes. Differential expression of connexins could create regions within the sinus node with different conduction properties, thereby contributing to the nonuniform conduction properties seen in this tissue.

Introduction: To elucidate the role of tissue structure as a determinant of the unique conduction properties of the sinus node, we compared the spatial distribution of intercellular connections at gap junctions in the sinus node to the more rapidly conducting crista terminalis and left ventricle, which have been studied previously., Methods and Results: Samples of four canine sinus nodes were prepared for electron microscopy. The total number and spatial orientation of neighboring myocytes connected by ultrastructurally identified intercalated disks and gap junctions to nine randomly selected index cells were determined by sequentially examining subserial sections. Sinus node cells were sparsely interconnected compared to the extent of interconnections observed previously in other tissues. A typical sinus node cell was connected to only 4.8 +/- 0.7 neighbors compared with 11.3 +/- 2.2 cells in the left ventricle and 6.4 +/- 1.7 cells in the crista terminalis. Sinus node interconnections occurred at small intercalated disks that usually connected cells in partial side-to-side and end-to-end juxtaposition. In contrast, left ventricular myocytes are interconnected at large intercalated disks that adjoin many cells in pure side-to-side and end-to-end orientations. Crista terminalis myocytes are connected primarily in end-to-end fashion. The aggregate gap junction profile length per unit myocyte area was 26.5 times greater in the left ventricle and 5.0 times greater in the crista terminalis than in the sinus node., Conclusion: Sinus node myocytes exhibit small, sparsely distributed gap junctions that interconnect cells in complex patterns of lateral and terminal apposition. These structural features are consistent with the unique conduction properties of the sinus node.

Electrical conduction is very rapid and highly anisotropic in atrial fiber bundles, such as the crista terminalis. In contrast to left ventricular myocardium in which the ratio of longitudinal to transverse conduction velocities is approximately 3, propagation velocity in the crista terminalis is approximately 10 times greater in the longitudinal than in the transverse direction. To elucidate potential determinants of these distinct conduction properties, we characterized structural and molecular features of intercellular coupling in the crista terminalis and left ventricular myocardium of the canine heart. Analysis of the number and spatial orientation of myocyte interconnections at gap junctions revealed that a typical left ventricular myocyte was connected to 11.3 +/- 2.2 other myocytes. Approximately equal numbers of connections occurred between ventricular myocytes juxtaposed in side-to-side and end-to-end orientation. In contrast, a typical myocyte of the crista terminalis was connected to only 6.4 +/- 1.7 other cells (P < .05), but nearly 80% of these connections occurred between cells oriented in an end-to-end configuration. In comparison with the ventricular pattern, this spatial distribution of connections would limit intercellular current transfer between laterally apposed cells and thereby enhance anisotropy of conduction velocity in the longitudinal and transverse directions. Ultrastructural analysis showed that crista terminalis myocytes were connected by numerous small gap junctions that occurred in relatively simple, straight intercalated disks. Northern blot analysis showed approximately equivalent amounts of mRNAs encoding the gap junction channel proteins connexin43 and connexin45 but approximately four times more connexin40 mRNA in crista terminalis than in the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

The subcellular distribution of Gs alpha was characterized in S49 lymphoma cells with two polyclonal antisera directed against specific COOH- and NH2-terminal epitopes. Nonspecific binding was determined in each subcellular compartment by incubating cyc- S49 cells, known to be deficient in Gs alpha and its mRNA, with primary and secondary antisera. Small proportions of total specific binding sites were localized to the plasmalemma as well as the nuclear envelope. Because of their small size, these compartments contained a high concentration of Gs alpha. However, most of the specific binding sites were found in nonstructured cytoplasm and within the nucleus. Specific binding was abolished or significantly reduced by preincubating primary antisera with their peptide immunogens but not with an irrelevant peptide. Intracellular Gs alpha immunoreactive binding sites did not colocalize with gold-conjugated transferrin in cells preincubated with this ligand to mark a classical endocytotic pathway. The intracellular and intranuclear location of Gs alpha was confirmed with confocal microscopy of S49 cells immunostained with specific primary and fluorescently labeled secondary antibodies. Gs alpha was also detected with immunoblots of proteins extracted from purified S49 cell nuclei. Thus, Gs alpha is abundantly distributed in intracellular and intranuclear sites in S49 cells and occurs in loci distinct from organelles of the transferrin pathway. The substantial intracellular distribution of Gs alpha suggests that Gs may subserve intracellular and, perhaps, intranuclear functions that may be important in proliferating cells.

We have recently shown that adult canine ventricular myocytes express three distinct gap junction channel proteins, connexin40 (Cx40), connexin43 (Cx43), and connexin45 (Cx45). These proteins have unique cytoplasmic domains that likely confer connexin-specific physiological properties. To determine whether the three distinct channel proteins are distributed in identical or different populations of gap junctions, we performed double-label immunofluorescence on disaggregated canine ventricular myocytes incubated simultaneously with a mouse monoclonal anti-Cx43 and affinity-purified polyclonal rabbit antibodies against Cx40 or Cx45. Analysis of double-labeled cardiac myocytes using laser scanning confocal microscopy revealed virtually identical patterns of immunoreactivity for both the Cx43/Cx40 and Cx43/Cx45 pairs. Double-label immunoelectron microscopy confirmed that ultrastructurally identified cardiac myocyte gap junctions contain multiple channel proteins. Thus, three channel proteins colocalize in canine cardiac myocyte gap junctions. The presence of multiple functionally distinct connexins suggests complex possibilities regarding the composition of individual channels and the regulation of intercellular coupling.

In the WHO sponsored trial of clofibrate and its follow-up, about 15,000 men were observed for a mean period of 13.2 years. As expected, incidence of heart attacks (HA) was directly related to serum cholesterol, blood pressure (BP) and cigarette smoking. The previously reported lower incidence of HA in men receiving clofibrate compared with controls was most noticeable in hypertensive heavy smokers (P less than 0.01). BP was slightly lower in smokers than non-smokers (P less than 0.01). The difference in BP was greater in the trial visit before HA. Smokers also had higher plasma fibrinogen levels (P less than 0.05). The combination of reduced diastolic BP, and therefore myocardial perfusion pressure, with an increased thrombogenic tendency, might explain the high incidence of HA in smokers. Clofibrate apparently reduced fibrinogen levels, which might account for its specially good effect in preventing HA in smokers. However, the ill effects of smoking are still evident at a lower level in the men taking clofibrate and the drug is no substitute for giving up the habit. Clofibrate is not recommended for widespread use, except in subjects with marked lipid and/or blood fibrinogen abnormalities after dietary measures have been tried.