Cultural adaptation and validation of the Quality of Dying in Long-term Care (QoD-LTC and QoD-LTC-C) scales by caregivers in nursing homes.

BACKGROUND: There is a lack of tools that can evaluate quality of dying in nursing homes from the perspective of deceased patients' caregivers. The aim of this study was to adapt and validate the caregivers' versions of the Quality of Dying in Long-Term Care (QoD-LTC) and Quality of Dying in Long-Term Care Complete (QoD-LTC-C) scales in the Spanish context. METHODS: This was a cultural adaptation and validation study. The scales were translated from English to Spanish and vice versa, and 13 experts in end-of-life care participated in a two-round Delphi panel. Caregivers of 69 deceased residents from seven nursing homes in southern Spain completed both scales. Reliability, feasibility, and concurrent validity with global quality of dying perception and symptom burden (Edmonton Symptom Assessment Scale), were evaluated. RESULTS: Spanish caregivers' version of the QoD-LTC scale showed good internal consistency for the total scale (α = 0.74) and each of its three factors, and good inter-rater reliability (ICC = 0.50) and test-retest reliability (ICC = 0.81). The Spanish QoD-LTC-C scale for caregivers showed good internal consistency for the total scale (α = 0.81) and for its component factors, and good test-retest reliability (ICC = 0.89) and inter-rater reliability (ICC = 0.66). Both scales correlated with family caregivers' global perception of deceased residents' quality of dying (r = 0.39; r = 0.32), but not with the ESAS score. CONCLUSIONS: Both scales presented an adequate factorial structure, internal consistency, and reliability to assess caregivers' perception of the quality of dying in Spanish nursing homes.

Quality of dying among elderly people diagnosed with dementia in nursing homes: A mixed methods study.

WHAT IS KNOWN ON THE SUBJECT: Nurses working at nursing homes can play a pivotal role in mental health as a high proportion of residents diagnosed with dementia are in these facilities. Many institutionalized residents diagnosed with dementia develop clinical complications and symptoms that reduce the quality of dying. A mixed-methods approach can help nurses with the difficult task of assessing the quality of dying among these residents and identify inconsistencies that cannot be found using scales alone, but no studies were found in this topic. WHAT THE PAPER ADDS TO EXISTING KNOWLEDGE: Through the Quality of dying in Long-Term Care Scale (QoD-LTC), nurses described symptom management, quality of care, and end-of-life appearance as adequate and end-of-life communication as lacking. Generally speaking, the scores on the scale were consistent with the data from semi-structured interviews conducted with nurses. In the semi-structured interviews, some of the concepts on the scale, including 'dignity', 'holistic' care, 'good relationships with healthcare professionals', and 'a peaceful death', are complex and not fully incorporated into nurses' practice in nursing homes when assessing residents diagnosed with dementia. This could be improved by using the SENSES Model or person-centred care frameworks. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: There is evidence of shortcomings among professionals in the correct use of concepts linked to psychological wellbeing, communication, therapeutic relationship, safety and participation, preservation of dignity, decision-making, and resident autonomy, which can be addressed using specific theoretical approaches developed in the field of mental health nursing. ABSTRACT: Introduction The complex nature of end-of-life assessment of individuals diagnosed with dementia would benefit from a mixed-methods approach that simultaneously assess the perception and response of nurses to standardized tools. Aim/Question To examine nursing professionals' perceptions of the quality of dying among residents diagnosed with dementia using the Quality of Dying in Long-Term Care settings (QoD-LTC) questionnaire and to identify consistencies and inconsistencies in their narratives. Method Mixed-methods study using concurrent triangulation with data integration for results and interpretation. Nurses from eight nursing homes assessed 117 residents diagnosed with dementia who died in the previous 3 months using the QoD-LTC scale. After informed consent was obtained (nurses/caregivers), 17 semi-structured scale-based interviews were conducted. Results Symptom management, quality of care, and end-of-life appearance were found to be adequate, while end-of-life communication was deemed insufficient. The qualitative and quantitative data were consistent for most of the items on the QoD-LTC. Discussion Concepts such as dignity, holistic care, good relationships, and peaceful death are complex and not fully incorporated into professional practice. Implications for Practice The results highlight the need for greater involvement of mental health nurses as well as improved communication, training, and specific tools tailored to residents diagnosed with dementia.

Cómo debemos analizar y describir la mortalidad de nuestros pacientes: experiencia del Grupo Centro Diálisis Peritoneal / How should we analyze and present mortality in our patients?: A multicentre GCDP experience

Introducción: Existen distintas estrategias para analizar la mortalidad en diálisis peritoneal (DP), con diferentes definiciones de caso, evento, tiempo en riesgo y análisis estadístico. Un método común entre los distintos registros permitiría compararlos adecuadamente y entender mejor las diferencias reales de mortalidad de nuestros pacientes. Métodos: Revisamos y describimos las estrategias de análisis de los registros autonómicos, nacional e internacionales. Incluimos análisis de supervivencia actuarial, Kaplan-Meier (KM) y riesgos-competitivos (RC). Aplicamos los diferentes enfoques a la misma base de datos (GCDP), lo que permite mostrar las diferencias aparentes con cada método. Resultados: Se incluyeron 1.890 pacientes incidentes en DP en el periodo 2003-2013 (55 años; 64,2% varones), con FRR inicial de 7ml/min; el 25% presentaba diabetes y un índice de Charlson de 3 [2-4]. Fallecieron 261 pacientes, 380 pasaron a hemodiálisis (HD) y 682 recibieron trasplante. Las tasas de mortalidad anual llegan a variar hasta un 20% en números relativos (6,4 vs. 5,2%) según el sistema aplicado. La estimación de probabilidad de mortalidad por RC es inferior a KM en todos los años: 3,6 vs. 4,0% el 1.er año; 9,0 vs. 11,9%; 15,6 vs. 28,3% y 18,5 vs. 43,3% los siguientes. Conclusiones: Aunque cada método pueda ser correcto en sí mismo y expresar diferentes enfoques, la impresión final que queda en el lector es un número que sobrestima la mortalidad. El modelo de RC expresa mejor la realidad en DP, donde el número de pacientes que pierden seguimiento (trasplante, paso a HD) cuadruplica al de los fallecidos y solo una cuarta parte continúa en DP al final del seguimiento (AU)

Introduction: There are different strategies to analyse mortality in peritoneal dialysis (PD) with different definitions for case, event, time at risk, and statistical tests. A common method for the different registries would enable proper comparison to better understand the actual differences in mortality of our patients. Methods: We review and describe the analysis strategies of regional, national and international registries. We include actuarial survival, Kaplan-Meier (KM) and competitive risk (CR) analyses. We apply different approaches to the same database (GCDP), which show apparent differences with each method. Results: A total of 1,890 incident patients in PD from 2003-2013 were included (55 years; men 64.2%), with initial RRF of 7 ml/min; 25% had diabetes and a Charlson index of 3 [2-4]; 261 patients died, 380 changed to haemodialysis (HD) and 682 received a transplant. Annual mortality rates varied up to 20% in relative numbers (6.4 vs. 5.2%) depending on the system applied. The estimated probability of mortality measured by CR progressively differs from the KM over the years: 3.6 vs. 4.0% the first year, then 9.0 vs. 11.9%, 15.6 vs. 28.3%, and 18.5 vs. 43.3% the following years. Conclusions: Although each method may be correct in themselves and express different approaches, the final impression left on the reader is a number that under/overestimates mortality. The CR model better expresses the reality of PD, where the number of patients lost to follow-up (transplant, transfer to HD) it is 4 times more than deceased patients and only a quarter remain on PD at the end of follow up (AU)

How should we analyze and present mortality in our patients?: A multicentre GCDP experience.

INTRODUCTION: There are different strategies to analyse mortality in peritoneal dialysis (PD) with different definitions for case, event, time at risk, and statistical tests. A common method for the different registries would enable proper comparison to better understand the actual differences in mortality of our patients. METHODS: We review and describe the analysis strategies of regional, national and international registries. We include actuarial survival, Kaplan-Meier (KM) and competitive risk (CR) analyses. We apply different approaches to the same database (GCDP), which show apparent differences with each method. RESULTS: A total of 1,890 incident patients in PD from 2003-2013 were included (55 years; men 64.2%), with initial RRF of 7ml/min; 25% had diabetes and a Charlson index of 3 [2-4]; 261 patients died, 380 changed to haemodialysis (HD) and 682 received a transplant. Annual mortality rates varied up to 20% in relative numbers (6.4 vs. 5.2%) depending on the system applied. The estimated probability of mortality measured by CR progressively differs from the KM over the years: 3.6 vs. 4.0% the first year, then 9.0 vs. 11.9%, 15.6 vs. 28.3%, and 18.5 vs. 43.3% the following years. CONCLUSIONS: Although each method may be correct in themselves and express different approaches, the final impression left on the reader is a number that under/overestimates mortality. The CR model better expresses the reality of PD, where the number of patients lost to follow-up (transplant, transfer to HD) it is 4 times more than deceased patients and only a quarter remain on PD at the end of follow up.

Study of the True Clinical Progression of Autosomal Dominant Alport Syndrome in a European Population.

BACKGROUND/AIMS: Autosomal dominant Alport syndrome represents 5% of all Alport syndrome cases. This entity presents a different clinical expression from the recessive inheritance pattern and the X chromosome-linked pattern, because it is mild and it shows a late onset, which in many cases even goes unnoticed. METHODS: We carried out a descriptive observational and retrospective clinical study on 19 patients from 5 families with a clinical diagnosis of autosomal dominant Alport Syndrome, and we analyzed the expression of the symptoms in the different families, comparing the results with what has been described in the literature. RESULTS: Renal involvement appeared at a young age, with a progression towards end-stage chronic kidney disease at a median age of 31 years (20.5-36.5). Hearing involvement also appeared in early stages, at a median age of 28.5 years (7.5-62.5). Also, we observed ocular lenticonus-like injuries, which until now have only been described in other inheritance patterns. CONCLUSIONS: Our results suggest that dominant patterns are accompanied by a severe clinical expression that can be superimposed to the recessive and X chromosome-linked patterns, contrary to what has been classically stated. The high phenotypic variability observed in the families lead to the fact that many cases go unnoticed and the severest cases are erroneously diagnosed as recessive, which means that the real prevalence of dominant forms is probably higher than the current 5%.

Peritoneal Dialysis Can Be an Option for Dominant Polycystic Kidney Disease: an Observational Study.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) has been considered a relative contraindication for peritoneal dialysis (PD), although there are few specific studies available. METHODS: A multicenter historical prospective matched-cohort study was conducted to describe the outcome of ADPKD patients who have chosen PD. All ADPKD patients starting PD (n = 106) between January 2003 and December 2010 and a control group (2 consecutive patients without ADPKD) were studied. Mortality, PD-technique failure, peritonitis, abdominal wall leaks and cyst infections were compared. RESULTS: Patients with ADPKD had similar age but less comorbidity at PD inclusion: Charlson comorbidity index (CCI) 4.3 (standard deviation [SD] 1.6) vs 5.3 (SD 2.5) p < 0.001, diabetes mellitus 5.7% vs 29.2%, p < 0.001 and previous cardiovascular events 10.4% vs 27.8%, p < 0.001. No differences were observed in clinical events that required transient transfer to hemodialysis, nor in peritoneal leakage episodes or delivered dialysis dose. The cyst infection rate was low (0.09 episodes per patient-year) and cyst infections were not associated to peritonitis episodes. Overall technique survival was similar in both groups. Permanent transfer to hemodialysis because of surgery or peritoneal leakage was more frequent in ADPKD. More ADPKD patients were included in the transplant waiting list (69.8 vs 58%, p = 0.04) but mean time to transplantation was similar (2.08 [1.69 - 2.47] years). The mortality rate was lower (2.5 vs 7.6 deaths/100 patient-year, p = 0.02) and the median patient survival was longer in ADPKD patients (6.04 [5.39 - 6.69] vs 5.57 [4.95 - 6.18] years, p = 0.024). CONCLUSION: Peritoneal dialysis is a suitable renal replacement therapy option for ADPKD patients.

COL4A4 gene study of a European population: description of new mutations causing autosomal dominant Alport syndrome.

BACKGROUND: Autosomal forms of Alport syndrome represent 20% of all patients (15% recessive and 5% dominant). They are caused by mutations in the COL4A3 and COL4A4 genes, which encode a-3 and a-4 collagen IV chains of the glomerular basement membrane, cochlea and eye. Thin basement membrane nephropathy may affect up to 1% of the population. The pattern of inheritance in the 40% of cases is the same as autosomal dominant Alport syndrome: heterozygous mutations in these genes. The aim of this study is to detect new pathogenic mutations in the COL4A4 gene in the patients previously diagnosed with autosomal Alport syndrome and thin basement membrane nephropathy in our hospital. METHODS: We conducted a clinical and genetic study in eleven patients belonging to six unrelated families with aforementioned clinical symptoms and a negative study of COL4A3 gene. The molecular study was made by conformation of sensitive gel electrophoresis (CSGE) and direct sequencing of the fragments that show an altered electrophoretic migration pattern. RESULTS: We found two pathogenic mutations, not yet described: IVS3 + 1G > C is a replacement of Guanine to Cytosine in position +1 of intron 3, in the splicing region, which leads to a pathogenic mutation. c.4267C > T; p.P1423S is a missense mutation, also considered pathogenic. We also found seven new polymorphisms. CONCLUSIONS: We describe two new pathogenic mutations, responsible for autosomal dominant Alport syndrome. The other families of the study were undiagnosed owing to problems in the method employed and the possibility of mutations in other genes, giving rise to other diseases with similar symptoms.

First episodes of peritoneal infection: description and prognostic factors.

INTRODUCTION: Peritonitis is one of the most common and severe complications associated with peritoneal dialysis (PD), constituting the primary cause of catheter loss and exit from the dialysis technique. The incidence and aetiology of peritonitis episodes vary based on geographical region, and change over time. For this reason, it is vital to maintain an updated understanding of the current risk factors and prognostic factors associated with peritonitis. METHOD: We performed an observational, multi-centre, prospective cohort study with a maximum follow-up period of 7 years (2003-2010), which included 1177 patients and a total of 476 first episodes of peritonitis (total: 1091 cases of peritonitis). RESULTS: We describe the characteristics of the first episode of peritonitis from a large and current study sample. The factors associated with a shorter interval until the first episode of peritonitis as selected by the multivariate analysis included prior cardiovascular comorbidity (Hazard Ratio [HR]: 1.25 [1.04-1.58]), having previously received haemodialysis (HR: 1.39 [1.10-1.76]) or a kidney transplant (HR: 1.38 [1.10-1.93]), having started PD on a manual modality (HR: 1.39 [1.13-1.73]), and initial age >70 years (HR: 1.53 [1.23-1.90]). The first episode of peritonitis was associated with a 7.8% rate of recurrence, an 11.7% rate of catheter removal, and a mortality rate within one month of the episode of 1.3%. The progression of peritonitis infections depended on the type of causal microorganism. We calculated a greater risk for gram-negative bacterial infections (Odds Ratio [OR]: 5.31 [2.26-12.48]) and the aggregate group of infections caused by multiple microorganisms, fungal infections, and mycobacterial infections (OR: 38.24 [13.84-105.63]), as compared to gram-positive bacterial infections. CONCLUSION: The development of a first case of peritonitis depends on the characteristics of the patient upon starting dialysis, comorbidities present, and the technique used. Patients at a greater risk for peritonitis must receive special care during training and follow-up.

Prevalencia de hipovitaminosis D en población trabajadora sanitaria / Prevalence of hypovitaminosis D in population Health Worker

Introducción: En los últimos años han ido apareciendo un gran número de artículos científicos evidenciando la elevada prevalencia de hipovitaminosis D en la población general. Objetivos: Analizar los niveles de vitamina D (vit. D) en un colectivo de trabajadores sanitarios. Material y métodos: Estudio descriptivo. Se analizaron mediante un inmunoensayo quimioluminiscente de micropartículas (CLIA), el analito 25 OH vit. D, y la Parathormona (PTH). Para el análisis bivariante se aplicó una chi cuadrado y la t-Student. La significación se consideró p< 0.05. Posteriormente se realizó una Regresión Logística (R.L.), cuya medida de asociación fue la Odds Ratio (O.R). Se han construido dos modelos uno considerando déficit de vit. D niveles inferiores a 30 ng/ml, y otro para niveles inferiores a 20 ng/ml. Resultados: Se ha observado una prevalencia de hipoavitaminosis D de 84.9 % (80.8 % - 89.1 %). Las variables tomar el Sol o UVA en el último mes, junto a los niveles de PTH, son las variables que están relacionadas con la Hipovitaminosis. Curiosamente, cuando se construye el modelo de R.L. con corte a los 20 ng/ml la única variable significativa es la exposición al sol. Conclusiones: Existe una prevalencia muy alta de hipovitaminosis D en los trabajadores sanitarios estudiados. La PTH tiene un comportamiento singular en función del punto de corte considerado en la vit.D (AU)

Introduction: In recent years have appeared a large number of scientific evidence of the high prevalence of hypovitaminosis D in the general population. Objectives: To analyze the levels of vit. D in a group of health workers. Methods: Descriptive study. Were analyzed by through microparticles chemiluminescent immunoassay (CLIA), the analyte 25 OH vit. D and Parathormone (PTHi). For the bivariate analysis chi-square an Student's t test was applied. Significance was considered p <0.05. Subsequently, it was performed a logistic regression (L.R.) whose measure of association was the odds ratio (OR). It has built two models, one considering deficit vit. D levels below 30 ng / ml, and another to levels, below 20 ng / ml. Results: It has been observed a prevalence of hipoavitaminosis D, of 84.9% (80.8% - 89.1%). Variables sunbathing or UVA in the last month together with PTHi levels, are the variables that are associated with hypovitaminosis Interestingly, when constructing LR model will cut at 20 ng / ml, sun exposure is the only significant variable. Conclusions: There is a very high prevalence of hypovitaminosis D in the health worker population studied. PTH has an odd behavior according with vit. D cutoff considered (AU)

Adrenocortical and behavioural response to chronic restraint stress in neurokinin-1 receptor knockout mice.

Brain substance P and its receptor (neurokinin-1, NK1) have a widespread brain distribution and are involved in an important number of behavioural and physiological responses to emotional stimuli. However, the role of NK1 receptors in the consequences of exposure to chronic stress has not been explored. The present study focused on the role of these receptors in the hypothalamic-pituitary-adrenal (HPA) response to daily repeated restraint stress (evaluated by plasma corticosterone levels), as well as on the effect of this procedure on anxiety-like behaviour, spatial learning and memory in the Morris water maze (MWM), a hippocampus-dependent task. Adult null mutant NK1-/- mice, with a C57BL/6J background, and the corresponding wild-type mice showed similar resting corticosterone levels and, also, did not differ in corticosterone response to a first restraint. Nevertheless, adaptation to the repeated stressor was faster in NK1-/- mice. Chronic restraint modestly increased anxiety-like behaviour in the light-dark test, irrespective of genotype. Throughout the days of the MWM trials, NK1-/- mice showed a similar learning rate to that of wild-type mice, but had lower levels of thigmotaxis and showed a better retention in the probe trial. Chronic restraint stress did not affect these variables in either genotype. These results indicate that deletion of the NK1 receptor does not alter behavioural susceptibility to chronic repeated stress in mice, but accelerates adaptation of the HPA axis. In addition, deletion may result in lower levels of thigmotaxis and improved short-term spatial memory, perhaps reflecting a better learning strategy in the MWM.

Long-term functional evolution after an acute kidney injury: a 10-year study.

BACKGROUND: Data on long-term effects of acute kidney injury (AKI) on renal function (RF) are scarce and factors implicated in the functional outcome are not established. Our aim was to investigate these aspects. METHODS: At hospital discharge and annually for 10 years, we retrospectively reviewed RF of 187 patients surviving AKI. Glomerular filtration rates estimated with MDRD equation (eGFR) and KDOQI stages were used to evaluate RF. Only 34.8% of patients had pre-existing renal dysfunction (KDOQI-3). Variables determining long-term RF were collected during AKI and at discharge and analysed with a regression model. RESULTS: At discharge no patient necessitated dialysis, but eGFR was lower than baseline (47.5 +/- 23.3 ml/min/ 1.73 m(2) versus 75.8 +/- 25.4 ml/min/1.73 m(2)); 38.4% of survivors had recovered basal RF: 26% of those with previous normal RF and 61% of those in KDOQI-3, respectively. At 1 year, eGFR increased to 61.9 +/- 24.4 ml/min/1.73 m(2) and remained stable later. During an 8-year median follow-up (P25:2; P75:10), 31% improved RF, 50% remained stable and 19% deteriorated. In total only 46% (n = 82) definitively recovered RF. Finally, at the end of the study period 61.6% presented some degree of renal dysfunction: 40% of those with previous normal RF developed moderate-severe renal dysfunction and 37% KDOQI-3 progressed into more severe renal failure. Only two patients needed dialysis. Regression model identified age, co-morbidities, discharge eGFR and follow-up time as independent predictors of long-term RF. CONCLUSIONS: AKI carries implication for long-term RF even in patients without pre-existing renal dysfunction. Ageing, co-morbidities and RF at discharge are determinants of the long-term functional outcome.

Portosystemic encephalopathy in a patient treated with peritoneal dialysis.

We present a case of a 75-year-old man with end-stage renal disease caused by immunoglobulin A nephropathy who developed hepatic encephalopathy 15 months after starting continuous ambulatory peritoneal dialysis therapy. Liver test results were normal except for hyperammonemia (ammonia, 317 microg/dL [186 micromol/L]) and mildly increased alkaline phosphatase and gamma-glutamyl transpeptidase levels. Abdominal ultrasonography showed normal liver architecture, and color Doppler ultrasonography showed a normal splenic-portal axis with hepatopetal blood flow. Histological examination of a laparoscopic liver biopsy specimen showed moderate fibrosis limited to portal tracts without necrosis or inflammation. Magnetic resonance angiography and percutaneous transhepatic portal angiography showed a large shunt between the left gastric and azygous veins, with blood flowing from the portal vein to the superior vena cava. The patient was transferred to hemodialysis treatment, and although his condition improved slightly, episodes of encephalopathy did not disappear. Surgical ligation of the left gastric vein was performed. In the 8 months after surgery, he has experienced no further episodes of hepatic encephalopathy or hyperammonemia. We speculate that increased intra-abdominal pressure and vasodilation caused by peritoneal dialysis solutions in a patient with a spontaneous portosystemic shunt resulted in ammonia-rich blood flow from the portal vein to the superior vena cava and encephalopathy. In addition, it is possible that chronic hepatic hypoxia caused by hypoperfusion from portosystemic shunting contributed to the development of liver fibrosis. To our knowledge, this is the first report of spontaneous portosystemic shunt encephalopathy in a patient with a noncirrhotic liver undergoing peritoneal dialysis.

Vanilloid receptor TRPV1, sensory C-fibers, and vascular autoregulation: a novel mechanism involved in myogenic constriction.

Myogenic constriction describes the innate ability of resistance arteries to constrict in response to elevations in intraluminal pressure and is a fundamental determinant of peripheral resistance and, hence, organ perfusion and systemic blood pressure. However, the receptor/cell-type that senses changes in pressure on the blood vessel wall and the pathway that couples this to constriction of vascular smooth muscle remain unclear. In this study, we show that elevation of intraluminal transmural pressure of mesenteric small arteries in vitro results in a myogenic response that is profoundly suppressed following ablation of sensory C-fiber activity (using in vitro capsaicin desensitization resulted in 72.8+/-10.3% inhibition, n=8; P<0.05). Activation of C-fiber nerve endings by pressure was attributable to stimulation of neuronal vanilloid receptor, TRPV1, because blockers of this channel, capsazepine (71.9+/-11.1% inhibition, n=9; P<0.001) and ruthenium red (46.1+/-11.7% inhibition, n=4; P<0.05), suppressed the myogenic constriction. In addition, this C-fiber dependency is likely related to neuropeptide substance P release and activity because blockade of tachykinin NK1 receptors (66.3+/-13.7% inhibition, n=6; P<0.001), and not NK2 receptors (n=4, NS), almost abolished the myogenic response. Previous studies support a role for 20-hydroxyeicosatetraenoic acid (20-HETE) in myogenic constriction responses; herein, we show that 20-HETE-induced constriction of mesenteric resistance arteries is blocked by capsazepine. Together, these results suggest that elevation of intraluminal pressure is associated with generation of 20-HETE that, in turn, activates TRPV1 on C-fiber nerve endings resulting in depolarization of nerves and consequent vasoactive neuropeptide release. These findings identify a novel mechanism contributing to Bayliss' myogenic constriction and highlights an alternative pathway that may be targeted in the therapeutics of vascular disease, such as hypertension, where enhanced myogenic constriction plays a role in the pathogenesis.

Bone cancer pain: the effects of the bisphosphonate alendronate on pain, skeletal remodeling, tumor growth and tumor necrosis.

Patients with metastatic breast, lung or prostate cancer frequently have significant bone cancer pain. In the present report we address, in a single in vivo mouse model, the effects the bisphosphonate alendronate has on bone cancer pain, bone remodeling and tumor growth and necrosis. Following injection and confinement of green fluorescent protein-transfected murine osteolytic tumor cells into the marrow space of the femur of male C3H/HeJ mice, alendronate was administered chronically from the time the tumor was established until the bone cancer pain became severe. Alendronate therapy reduced ongoing and movement-evoked bone cancer pain, bone destruction and the destruction of sensory nerve fibers that innervate the bone. Whereas, alendronate treatment did not change viable tumor burden, both tumor growth and tumor necrosis increased. These data emphasize that it is essential to utilize a model where pain, skeletal remodeling and tumor growth can be simultaneously assessed, as each of these can significantly impact patient quality of life and survival.

Serotonin transporter in substance P (neurokinin 1) receptor knock-out mice.

We recently demonstrated that mice lacking the gene for substance P (neurokinin 1) receptors (NK1-/-) show improved cortical dialysate serotonin (5-HT) responses to paroxetine [J. Neurosci. 21 (2001) 8188]. To test for changes that may involve the 5-HT transporter (5-HTT) in these mutant mice, in vivo/in vitro studies were performed. Autoradiographic quantification of 5-HTT was performed: [3H]citalopram binding did not reveal any modification of 5-HT binding sites in the dorsal raphe nucleus (DRN) of wild-type NK1+/+ control and mutant NK1-/- mice. These results were further confirmed by 5-HTT mRNA quantification using competitive reverse transcription and polymerase chain reaction (RT-PCR) assay, which showed similar messenger levels in the DRN of both mice genotypes. The functional status of 5-HTT in vivo was tested by using the zero net flux method of quantitative microdialysis in two serotonergic nerve terminal regions, the frontal cortex and ventral hippocampus, of wild-type NK1+/+ and NK1-/- mice. Neither basal extracellular 5-HT levels nor the 5-HT extraction fraction of the probe (Ed an index of 5-HT uptake in vivo) differed between wild-type and mutant mice in the two brain regions studied. These results suggest that no compensatory response to the constitutive deletion of the tachykinin NK1 receptor involving changes in the activity of the selective 5-HT transporter occurred in the DRN, frontal cortex and ventral hippocampus in mice.

Blockade of substance P (neurokinin 1) receptors enhances extracellular serotonin when combined with a selective serotonin reuptake inhibitor: an in vivo microdialysis study in mice.

Abstract Substance P antagonists of the neurokinin-1 receptor type (NK1) are gaining growing interest as new antidepressant therapies. It has been postulated that these drugs exert this putative therapeutic effect without direct interactions with serotonin (5-HT) neurones. Our recent microdialysis experiment performed in NK1 receptor knockout mice suggested evidence of changes in 5-HT neuronal function (Froger et al. 2001). The aim of the present study was to evaluate the effects of coadministration of the selective 5-HT reuptake inhibitor (SSRI) paroxetine with a NK1 receptor antagonist (GR205171 or L733060), given either intraperitoneally (i.p.) or locally into the dorsal raphe nucleus, on extracellular levels of 5-HT ([5-HT]ext) in the frontal cortex and the dorsal raphe nucleus using in vivo microdialysis in awake, freely moving mice. The systemic or intraraphe administration of a NK1 receptor antagonist did not change basal cortical [5-HT]ext in mice. A single systemic dose of paroxetine (4 mg/kg; i.p.) resulted in a statistically significant increase in [5-HT]ext with a larger extent in the dorsal raphe nucleus (+ 138% over basal AUC values), than in the frontal cortex (+ 52% over basal AUC values). Co-administration of paroxetine (4 mg/kg; i.p.) with the NK1 receptor antagonists, GR205171 (30 mg/kg; i.p.) or L733060 (40 mg/kg; i.p.), potentiated the effects of paroxetine on cortical [5-HT]ext in wild-type mice, whereas GR205171 (30 mg/kg; i.p.) had no effect on paroxetine-induced increase in cortical [5-HT]ext in NK1 receptor knock-out mice. When GR205171 (300 micro mol/L) was perfused by 'reverse microdialysis' into the dorsal raphe nucleus, it potentiated the effects of paroxetine on cortical [5-HT]ext, and inhibited paroxetine-induced increase in [5-HT]ext in the dorsal raphe nucleus. Finally, in mice whose 5-HT transporters were first blocked by a local perfusion of 1 micro mol/L of citalopram into the frontal cortex, a single dose of paroxetine (4 mg/kg i.p.) decreased cortical 5-HT release, and GR205171 (30 mg/kg i.p.) reversed this effect. The present findings suggest that NK1 receptor antagonists, when combined with a SSRI, augment 5-HT release by modulating substance P/5-HT interactions in the dorsal raphe nucleus.

Generation of embryonic stem cells and transgenic mice expressing green fluorescence protein in midbrain dopaminergic neurons.

We have generated embryonic stem (ES) cells and transgenic mice with green fluorescent protein (GFP) inserted into the Pitx3 locus via homologous recombination. In the central nervous system, Pitx3-directed GFP was visualized in dopaminergic (DA) neurons in the substantia nigra and ventral tegmental area. Live primary DA neurons can be isolated by fluorescence-activated cell sorting from these transgenic mouse embryos. In culture, Pitx3-GFP is coexpressed in a proportion of ES-derived DA neurons. Furthermore, ES cell-derived Pitx3-GFP expressing DA neurons responded to neurotrophic factors and were sensitive to DA-specific neurotoxin N-4-methyl-1, 2, 3, 6-tetrahydropyridine. We anticipate that the Pitx3-GFP ES cells could be used as a powerful model system for functional identification of molecules governing mDA neuron differentiation and for preclinical research including pharmaceutical drug screening and transplantation. The Pitx3 knock-in mice, on the other hand, could be used for purifying primary neurons for molecular studies associated with the midbrain-specific DA phenotype at a level not previously feasible. These mice would also provide a useful tool to study DA fate determination from embryo- or adult-derived neural stem cells.

Mechanisms of action of the antidepressants fluoxetine and the substance P antagonist L-000760735 are associated with altered neurofilaments and synaptic remodeling.

Antidepressants are widely prescribed in the treatment of depression, although the mechanism of how they exert their therapeutic effects is poorly understood. To shed further light on their mode of action, we have attempted to identify a common proteomic signature in guinea pig brains after chronic treatment with two different antidepressants. Both fluoxetine and the substance P receptor (NK(1)R) antagonist (SPA) L-000760735 altered cortical expression of multiple heat shock protein 60 forms along with neurofilaments and related proteins that are critical determinants of synaptic structure and function. Analysis of NK(1)R-/- mice showed similar alterations of neurofilaments confirming the specificity of the effects observed with chronic NK(1)R antagonist treatment. To determine if these changes were associated with structural modification of synapses, we carried out electron microscopic analysis of cerebral cortices from fluoxetine-treated guinea pigs. This showed an increase in the percentage of synapses with split postsynaptic densities (PSDs), a phenomenon that is characteristic of activity-dependent synaptic rearrangement. These findings suggest that cortical alterations of the neurofilament pathway and increased synaptic remodeling are associated with the mechanism of these two antidepressant drug treatments and may contribute to their psychotherapeutic actions.