Guidelines on the management of ascites in cirrhosis

The British Society of Gastroenterology in collaboration with British Association for the Study of the Liver has prepared this document. The aim of this guideline is to review and summarise the evidence that guides clinical diagnosis and management of ascites in patients with cirrhosis. Substantial advances have been made in this area since the publication of the last guideline in 2007. These guidelines are based on a comprehensive literature search and comprise systematic reviews in the key areas, including the diagnostic tests, diuretic use, therapeutic paracentesis, use of albumin, transjugular intrahepatic portosystemic stent shunt, spontaneous bacterial peritonitis and beta-blockers in patients with ascites. Where recent systematic reviews and meta-analysis are available, these have been updated with additional studies. In addition, the results of prospective and retrospective studies, evidence obtained from expert committee reports and, in some instances, reports from case series have been included. Where possible, judgement has been made on the quality of information used to generate the guidelines and the specific recommendations have been made according to the 'Grading of Recommendations Assessment, Development and Evaluation (GRADE)' system. These guidelines are intended to inform practising clinicians, and it is expected that these guidelines will be revised in 3 years' time.

Albumin in decompensated cirrhosis: new concepts and perspectives

The pathophysiological background of decompensated cirrhosis is characterised by a systemic proinflammatory and pro-oxidant milieu that plays a major role in the development of multiorgan dysfunction. Such abnormality is mainly due to the systemic spread of bacteria and/or bacterial products from the gut and danger-associated molecular patterns from the diseased liver triggering the release of proinflammatory mediators by activating immune cells. The exacerbation of these processes underlies the development of acute-on-chronic liver failure. A further mechanism promoting multiorgan dysfunction and failure likely consists with a mitochondrial oxidative phosphorylation dysfunction responsible for systemic cellular energy crisis. The systemic proinflammatory and pro-oxidant state of patients with decompensated cirrhosis is also responsible for structural and functional changes in the albumin molecule, which spoil its pleiotropic non-oncotic properties such as antioxidant, scavenging, immune-modulating and endothelium protective functions. The knowledge of these abnormalities provides novel targets for mechanistic treatments. In this respect, the oncotic and non-oncotic properties of albumin make it a potential multitarget agent. This would expand the well-established indications to the use of albumin in decompensated cirrhosis, which mainly aim at improving effective volaemia or preventing its deterioration. Evidence has been recently provided that long-term albumin administration to patients with cirrhosis and ascites improves survival, prevents complications, eases the management of ascites and reduces hospitalisations. However, variant results indicate that further investigations are needed, aiming at confirming the beneficial effects of albumin, clarifying its optimal dosage and administration schedule and identify patients who would benefit most from long-term albumin administration.

Defective monocyte oxidative burst predicts infection in alcoholic hepatitis and is associated with reduced expression of NADPH oxidase

OBJECTIVE

In order to explain the increased susceptibility to serious infection in alcoholic hepatitis, we evaluated monocyte phagocytosis, aberrations of associated signalling pathways and their reversibility, and whether phagocytic defects could predict subsequent infection.

DESIGN

Monocytes were identified from blood samples of 42 patients with severe alcoholic hepatitis using monoclonal antibody to CD14. Phagocytosis and monocyte oxidative burst (MOB) were measured ex vivo using flow cytometry, luminometry and bacterial killing assays. Defects were related to the subsequent development of infection. Intracellular signalling pathways were investigated using western blotting and PCR. Interferon-γ (IFN-γ) was evaluated for its therapeutic potential in reversing phagocytic defects. Paired longitudinal samples were used to evaluate the effect of in vivo prednisolone therapy.

RESULTS

MOB, production of superoxide and bacterial killing in response to Escherichia coli were markedly impaired in patients with alcoholic hepatitis. Pretreatment MOB predicted development of infection within two weeks with sensitivity and specificity that were superior to available clinical markers. Accordingly, defective MOB was associated with death at 28 and 90 days. Expression of the gp91 ^phox subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase was reduced in patients with alcoholic hepatitis demonstrating defective MOB. Monocytes were refractory to IFN-γ stimulation and showed high levels of a negative regulator of cytokine signalling, suppressor of cytokine signalling-1. MOB was unaffected by 7 days in vivo prednisolone therapy.

CONCLUSIONS

Monocyte oxidative burst and bacterial killing is impaired in alcoholic hepatitis while bacterial uptake by phagocytosis is preserved. Defective MOB is associated with reduced expression of NADPH oxidase in these patients and predicts the development of infection and death.

ATTIRE: Albumin To prevenT Infection in chronic liveR failurE: study protocol for a single-arm feasibility trial

INTRODUCTION

Circulating prostaglandin E2 levels are elevated in acutely decompensated cirrhosis and have been shown to contribute to immune suppression. Albumin binds and inactivates this hormone. Human albumin solution could thus be repurposed as an immune restorative drug in these patients.This feasibility study aims to determine whether it is possible and safe to restore serum albumin to >30 g/L and maintain it at this level in patients admitted with acute decompensated cirrhosis using repeated 20% human albumin infusions according to daily serum albumin levels.

METHODS AND ANALYSIS

Albumin To prevenT Infection in chronic liveR failurE (ATTIRE) stage 1 is a multicentre, open label dose feasibility trial. Patients with acutely decompensated cirrhosis admitted to hospital with a serum albumin of <30 g/L are eligible, subject to exclusion criteria. Daily intravenous human albumin solution will be infused, according to serum albumin levels, for up to 14 days or discharge in all patients. The primary end point is daily serum albumin levels for the duration of the treatment period and the secondary end point is plasma-induced macrophage dysfunction. The trial will recruit 80 patients. Outcomes will be used to assist with study design for an 866 patient randomised controlled trial at more than 30 sites across the UK.

ETHICS AND DISSEMINATION

Research ethics approval was given by the London-Brent research ethics committee (ref: 15/LO/0104). The clinical trials authorisation was issued by the medicines and healthcare products regulatory agency (ref: 20363/0350/001-0001).

RESULTS

Will be disseminated through peer reviewed journals and international conferences. Recruitment of the first participant occurred on 26/05/2015.

TRIAL REGISTRATION NUMBER

The trial is registered with the European Medicines Agency (EudraCT 2014-002300-24) and has been adopted by the NIHR (ISRCTN 14174793). This manuscript refers to V.4.0 of the protocol; Pre-results.

Immunosuppression in acutely decompensated cirrhosis is mediated by prostaglandin E2

Liver disease is one of the leading causes of death worldwide. Patients with cirrhosis display an increased predisposition to and mortality from infection due to multimodal defects in the innate immune system; however, the causative mechanism has remained elusive. We present evidence that the cyclooxygenase (COX)-derived eicosanoid prostaglandin E2 (PGE2) drives cirrhosis-associated immunosuppression. We observed elevated circulating concentrations (more than seven times as high as in healthy volunteers) of PGE2 in patients with acute decompensation of cirrhosis. Plasma from these and patients with end-stage liver disease (ESLD) suppressed macrophage proinflammatory cytokine secretion and bacterial killing in vitro in a PGE2-dependent manner via the prostanoid type E receptor-2 (EP2), effects not seen with plasma from patients with stable cirrhosis (Child-Pugh score grade A). Albumin, which reduces PGE2 bioavailability, was decreased in the serum of patients with acute decompensation or ESLD (<30 mg/dl) and appears to have a role in modulating PGE2-mediated immune dysfunction. In vivo administration of human albumin solution to these patients significantly improved the plasma-induced impairment of macrophage proinflammatory cytokine production in vitro. Two mouse models of liver injury (bile duct ligation and carbon tetrachloride) also exhibited elevated PGE2, reduced circulating albumin concentrations and EP2-mediated immunosuppression. Treatment with COX inhibitors or albumin restored immune competence and survival following infection with group B Streptococcus. Taken together, human albumin solution infusions may be used to reduce circulating PGE2 levels, attenuating immune suppression and reducing the risk of infection in patients with acutely decompensated cirrhosis or ESLD.

Lipid mediators in immune dysfunction after severe inflammation

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Aberrant LM levels contribute to immune dysfunction in CI.

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Aberrance reflects dysregulation of inflammatory resolution pathways or their failure.

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Targeted manipulation of LMs restores immune competence and outcomes in animal models.

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Stratified resolution-based immunomodulatory strategies hold therapeutic potential.

Sepsis, trauma, burns, and major surgical procedures activate common systemic inflammatory pathways. Nosocomial infection, organ failure, and mortality in this patient population are associated with a quantitatively different reprioritization of the circulating leukocyte transcriptome to the initial inflammatory insult, greater in both magnitude and duration, and secondary to multiple observed defects in innate and adaptive immune function. Dysregulation of inflammatory resolution processes and associated bioactive lipid mediators (LMs) mechanistically contribute to this phenotype. Recent data indicate the potential efficacy of therapeutic interventions that either reduce immunosuppressive prostaglandins (PGs) or increase specialized proresolving LMs. Here, we reassess the potential for pharmacological manipulation of these LMs as therapeutic approaches for the treatment of critical illness (CI).

Pathways mediating resolution of inflammation: when enough is too much

Patients with critical illness, and in particular sepsis, are now recognized to undergo unifying, pathogenic disturbances of immune function. Whilst scientific and therapeutic focus has traditionally been on understanding and modulating the initial pro-inflammatory limb, recent years have witnessed a refocusing on the development and importance of immunosuppressive 'anti-inflammatory' pathways. Several mechanisms are known to drive this phenomenon; however, no overriding conceptual framework justifies them. In this article we review the contribution of pro-resolution pathways to this phenotype, describing the observed immune alterations in terms of either a failure of resolution of inflammation or the persistence of pro-resolution processes causing inappropriate 'injurious resolution'-a novel hypothesis. The dysregulation of key processes in critical illness, including apoptosis of infiltrating neutrophils and their efferocytosis by macrophages, are discussed, along with the emerging role of specialized cell subtypes Gr1(+) CD11b(+) myeloid-derived suppressor cells and CD4(+) CD25(+) FoxP3(+) T-regulatory cells.

Prevalence and outcome of cirrhosis patients admitted to UK intensive care: a comparison against dialysis-dependent chronic renal failure patients

PURPOSE

Patients with decompensated liver cirrhosis who are admitted to intensive care units (ICU) are perceived, within the UK, as having a particularly poor prognosis.

METHODS

We performed a descriptive analysis of cirrhosis patients admitted to general critical care units 1995-2008 compared to patients admitted with pre-existing chronic renal failure. Data were obtained from the Intensive Care National Audit and Research Centre Case Mix Programme Database incorporating 192 adult critical care units in England, Wales and Northern Ireland.

RESULTS

Cirrhosis accounted for 2.6 % (16,096 patients) of total admissions with mean age 52.5 years and male preponderance (~60 %). Hospital mortality was high (>55 %) although this improved 5 % in recent years, and median length of stay was short (2.5 days). Mortality in cirrhotics with severe sepsis requiring organ support was 65-90 %, compared to 33-39 % in those without. Conversely, patients with chronic renal failure had lower mortality (42 %) despite similar characteristics and higher acute physiology and chronic health evaluation (APACHE) II scores. The APACHE II score under-predicted mortality in cirrhotics.

CONCLUSIONS

Cirrhosis patients exhibit worse outcomes compared to pre-existing renal failure patients, despite similar characteristics. Survival worsens considerably with organ failure, especially with sepsis. They represent a small number of admissions, albeit increasing over recent years, and, in general, have a short ICU stay. Patients with single organ failure have acceptable survival rates and mortality has improved; although we have no data on those refused ICU admission potentially causing survival bias. Given the extremely high mortality in patients with multi-organ failure, support should be limited/withdrawn in such patients.

Improving the ability of mental health nurses to give second opinion in Judicial Reviews: an evaluation study

In New Zealand, concern has been expressed regarding the variable quality of second opinions given by health professionals assisting judicial decisions on the use of compulsory assessment and treatment under mental health legislation. This second opinion is mostly given by registered mental health nurses. An innovative education programme based on experiential learning and adult learning principles was developed to assist health professionals to effectively undertake this role. A mixed method pre-post test intervention research design was developed to evaluate the effectiveness of the programme in assisting health professionals to feel more competent in undertaking the role. Data from the participants (n= 112) was subjected to descriptive statistical analysis and a thematic analysis of open-ended questions. The findings suggested gains in all competencies following the education programme, although there was room for further improvement. These changes were sustained over time at the next occasion when the health professionals undertook the role. There is a need to nationally disseminate such educational innovations to assist more mental health nurses to maximize their input into judicial decisions, which have a marked impact on the lives of those service users involved.

The role of second health professionals under New Zealand mental health legislation

The development of generic statutory roles in mental health care has been the subject of discussion by New Zealand nurses for the past decade. One such role is that of second health professional in judicial reviews of civil commitment. Issues identified by New Zealand nurses have also been raised in England, where it seems that nurses are likely to assume the role of Approved Mental Health Worker under English mental health law. A survey of mental health nurses found that few had received any preparation for the role of second health professional and 45% did not feel adequately prepared for the role. Some of these issues are reflected in a New Zealand inquiry which resulted in the Ministry of Health developing a written report form for second health professionals. However, the form has the potential to reduce the mental health nursing role to a narrow legal role. Statutory roles such as that of second health professional challenge mental health nurses to critically reflect on the conceptual and ethical basis of their practice. While traditional concepts such as therapeutic relationships and advocacy need to be reviewed in light of these changes, nurses need to be vigilant in articulating the moral and clinical basis of their roles. The development of guidelines for he second health professional role is suggested as a way of supporting clinical practice in this area.

World without borders: integrating clinical perspectives into the coronial jurisdiction in Victoria, Australia

A professional world without borders would allow for more appropriate collaboration between the Coroner's office and the healthcare sector in their endeavours to improve patient safety. In Victoria (Australia), the Clinical Liaison Service draws on the distinct experiences and expertise of medical, nursing and research personnel to evaluate clinical evidence for the investigation of healthcare deaths reported to the State Coroner's Office. This approach allows for greater intersectoral collaboration between the Coroner's office and healthcare sector than a traditional English-style coronial system that relies on the expertise of coroners, forensic pathologists and police officers to investigate unexpected deaths. Encouraging collaboration between these two sectors may have averted or at least mitigated the atrocities caused by Harold Shipman or the events at Bristol's Royal Infirmary. This paper describes the work processes employed by the Clinical Liaison Service (CLS) to investigate healthcare deaths in a coronial setting. To describe how this work has fostered the advancement of patient care.

The pore-forming subunit of the K(ATP) channel is an important molecular target for LPS-induced vascular hyporeactivity in vitro

ATP-sensitive K(+) (K(ATP)) channel activation is implicated in the vascular hyporeactivity occurring in septic shock. However, channel inhibition with the sulphonylurea receptor (SUR) antagonist, glibenclamide (Glib) fails to reverse lipopolysaccharide (LPS)-induced vascular hyporeactivity in vitro. We investigated whether inhibitors that act by binding to the K(ATP) channel pore could be effective. Ring segments of endothelium-intact rat mesenteric artery were incubated with LPS in culture media for either 6 or 20 h before contractile responses to phenylephrine were assessed in the absence or presence of K(ATP) channel inhibitors. The pore-forming subunit inhibitors barium chloride (BaCl(2); 300 microM) and PNU-37883A (1 microM) significantly reversed hyporeactivity at both time points, although less so at 20 h. In contrast, the SUR inhibitors, Glib (10 microM), tolbutamide (Tolb) (1 mM) and PNU-99963 (1 microM) were ineffective. In LPS-incubated tissues, Glib and Tolb antagonised contractions to the thromboxane A2 mimetic, U46619 (9,11-dideoxy-9alpha, 11alpha-methanoepoxy prostaglandin F(2alpha)) (10(-7) M), whereas the pinacidil-derived inhibitor, PNU-99963, did not. Contractions to 60 mM KCl were unaffected by LPS at 6 h, but were significantly depressed by LPS at 20 h, suggesting that K(+)-channel-independent pathways contribute to hyporeactivity at the later time point. The inducible nitric oxide synthase (iNOS) inhibitor, 1400 W (10 microM) and Tolb inhibited the production of nitrite induced by LPS, whereas BaCl(2) and PNU-37883A had no effect. In conclusion, K(ATP) channels contribute to LPS-induced vascular hyporeactivity via the iNOS pathway in rat mesenteric artery. The effectiveness of pore inhibitors over SUR inhibitors of the K(ATP) channel suggests altered SUR function following LPS administration, which cannot be explained by thromboxane receptor inhibition.

Renal tubular proteinuria in patients with irritable bowel syndrome

OBJECTIVE

Irritable bowel syndrome (IBS) is a common condition that is poorly understood. We have previously demonstrated tubular protinuria in patients with inflammatory bowel disease. This study examined whether tubular proteinuria was a feature of IBS.

METHODS

Eighty control subjects (male:female, 28:52; age range 20-65 years) and 21 patients with IBS (male:female, 9:12; age range 16-64 years) (not significant) were recruited. Patients with known renal disease, hypertension, diabetes or microbiological evidence of urinary infection were excluded. The IBS patients all fulfilled the ROME II criteria. None had preceding gastroenteritis. Urinary alpha1-microglobulin (alpha1-M) was measured in a second-voided morning urine sample and corrected for urinary concentration by measurement of creatine. Blood samples were analysed for haematochemical indices including C-reactive protein. Statistical analysis was by unpaired t test.

RESULTS

None of the IBS patients were reclassified with inflammatory bowel disease over a 5-year follow up period. All had normal haematochemical parameters. Mean +/- standard deviation urinary alpha1-M concentrations were significantly higher in IBS patients than controls (IBS patients, 1.17 +/- 0.65 mg/mmol; controls, 0.75 +/- 0.36 mg/mmol; P < 0.01) and exceeded 1.5 mg/mmol (the upper reference limit) in seven patients. There was no difference in urinary alpha1-M concentrations in the diarrhoea-predominant and constipation-predominant groups (mean +/- standard deviation, 1.342 +/- 0.65 versus 0.76 +/- 0.48 mg/mmol; P = 0.062).

CONCLUSIONS

Urinary alpha1-M concentration is commonly increased in IBS, suggesting the presence of renal proximal tubular injury.

Coercion in mental healthcare: the principle of least coercive care

Coercive practices are relatively common in mental healthcare, but coercion is ethically problematic because it involves acting against an individual's autonomy. However, coercion is often poorly defined in mental health literature, resulting in problems in considering coercion from an ethical perspective. This paper challenges the traditional paternalistic justification for coercive practices in mental healthcare, and argues that the failure to make a conceptual distinction between what counts as coercive practice and what justifies coercive practice results in instances of unjustified use of coercion. It also results in the failure to recognize other justifications for coercive practice. We propose a broad definition of coercion that recognizes the prevalence of coercion in mental healthcare. In particular, we wish to recognize the potential for persuasion and manipulation of clients' wishes to be coercive. We argue that there should be a prima facie ban on coercion in mental healthcare, and that the use of coercive practices needs to be justified in the specific circumstances of each case. The presupposition that mental illness involves limited autonomy cannot be taken to justify use of coercion. We outline a principle of least coercive intervention that we think has the potential to lessen the prevalence and extent of coercion in mental healthcare.

Unearthing the conflicts between carer and custodian: implications of participation in Section 16 hearings under the Mental Health (Compulsory Assessment and Treatment) Act (1992)

Mental health nursing occurs within a legal and ethical framework that presents conflicts between a paternalistic custodial role and an ethical commitment to autonomy. This paper considers the ethical conflict for nurses posed by acting as second health professional at judicial reviews under Section 16 of the Mental Health (Compulsory Treatment and Assessment) Act. Issues of advocacy and paternalism are discussed in light of the conflict between therapeutic and legislated roles. Strategies aimed at protecting the therapeutic relationship are outlined as a response to the current lack of guidelines in this area. Participation in legal processes of committal requires that nurses reflect carefully and critically on the ethical issues raised.

Temporal variation in endotoxin-induced vascular hyporeactivity in a rat mesenteric artery organ culture model

Endotoxin-induced vascular hyporeactivity to phenylephrine (PE) is well described in rodent aorta, but has not been investigated in smaller vessels in vitro. Segments of rat superior mesenteric artery were incubated in culture medium with or without foetal bovine serum (10%) for 6, 20 or 46 h in the presence or absence of bacterial lipopolysaccharide (LPS; 1 - 100 microg ml(-1)). Contractions to PE were measured with or without nitric oxide synthase (NOS) inhibitors: L-NAME (300 microM), aminoguanidine (AMG; 400 microM) 1400W (10 microM) and GW273629 (10 microM); the guanylyl cyclase inhibitor, ODQ (3 microM); the COX-2 inhibitor, NS-398 (10 microM). Contractile responses to the thromboxane A2 mimetic, U46619 were also assessed. In the presence of serum, LPS induced hyporeactivity at all time points. In its absence, hyporeactivity only occurred at 6 and 20 h. L-NAME and AMG fully reversed hyporeactivity at 6 h, whereas they were only partially effective at 20 h and not at all at 46 h. In contrast partial reversal of peak contraction was observed with 1400W (62% at 46 h), GW273629 (57% at 46 h) and ODQ (75% at 46 h). COX-2 inhibition produced no reversal. In contrast to PE, contractions to U46619 were substantially less affected by LPS. We describe a well-characterized reproducible model of LPS-induced hyporeactivity, which is largely mediated by the NO-cyclic GMP-dependent pathway. Importantly, long-term (2-day) production of NO via iNOS is demonstrated. Moreover, conventional doses of L-NAME and AMG became increasingly ineffective over time. Thus, the choice of inhibitor merits careful consideration in long-term models.

The therapeutic relationship: historical development and contemporary significance

The therapeutic relationship is a concept held by many to be fundamental to the identity of mental health nurses. While the therapeutic relationship was given formal expression in nursing theory in the middle of the last century, its origins can be traced to attendants' interpersonal practices in the asylum era. The dominance of medical understandings of mental distress, and the working-class status of asylum attendants, prevented the development of an account of mental health nursing based on attendants' relationships with asylum inmates. It was left to Peplau and other nursing theorists to describe mental health nursing as a therapeutic relationship in the 1940s and later. Some distinctive features of colonial life in New Zealand suggest that the ideal of the attendant as the embodiment of bourgeoisie values seems particularly unlikely to have been realized in the New Zealand context. However, New Zealand literature from the 20th century shows that the therapeutic relationship, as part of a general development of a therapeutic discourse, came to assume a central place in conceptualizations of mental health nursing. While the therapeutic relationship is not by itself a sufficient basis for professional continuity, it continues to play a fundamental role in mental health nurses' professional identity. The way in which the therapeutic relationship is articulated in the future will determine the meaning of the therapeutic relationship for future generations of mental health nurses.

Negotiating the relationship: mental health nurses' perceptions of their practice

This exploratory descriptive study used focus groups to investigate experienced mental health nurses' perceptions of expertise in relation to their practice. Two focus group discussions were conducted, one comprising four nurses working in inpatient care and the other with five nurses working in community care. The nurse-patient relationship was the central theme for both groups. Three sub-themes were identified and are discussed. They are involvement, individualizing care, and minimising visibility. The significance of these themes for the articulation of mental health nursing practice is discussed.

Relationships between NADPH diaphorase staining and neuronal, endothelial, and inducible nitric oxide synthase and cytochrome P450 reductase immunoreactivities in guinea-pig tissues

The presence of NADPH diaphorase staining was compared with the immunohistochemical localization of four NADPH-dependent enzymes-neuronal (type I), inducible (type II), and endothelial (type III) nitric oxide synthase (NOS) and cytochrome P450 reductase. Cell types that were immunoreactive for the NADPH-dependent enzymes were also stained for NADPH diaphorase, suggesting that endothelial and neuronal NOS and cytochrome P450 reductase all show NADPH diaphorase activity in formaldehyde-fixed tissue. However, in some tissues, the presence of NADPH diaphorase staining did not coincide with the presence of any of the NADPH-dependent enzymes we examined. In vascular endothelial cells, the punctate pattern of staining observed with NADPH diaphorase histochemistry was identical to that seen following immunohistochemistry using antibodies to endothelial NOS. In enteric and pancreatic neurons and in skeletal muscle, the presence of NADPH diaphorase staining correlated with the presence of neuronal NOS. In the liver, sebaceous glands of the skin, ciliated epithelium, and a subpopulation of the cells in the subserosal glands of the trachea, zona glomerulosa of the adrenal cortex, and epithelial cells of the lacrimal and salivary glands, the presence of NADPH diaphorase staining coincided with the presence of cytochrome P450 reductase immunoreactivity. In epithelial cells of the renal tubules and zona fasciculata and zona reticularis of the adrenal cortex, NADPH diaphorase staining was observed that did not coincide with the presence of any of the enzymes. Inducible NOS was not observed in any tissue. Thus, while tissues that demonstrate immunoreactivity for neuronal and endothelial NOS also stain positively for NADPH diaphorase activity, the presence of NADPH diaphorase staining does not reliably or specifically indicate the presence of one or more NOS isoforms.

Nitric oxide synthase is localized predominantly in the Golgi apparatus and cytoplasmic vesicles of vascular endothelial cells

The localization of nitric oxide synthase (NOS) in vascular endothelial cells of submucosal blood vessels from the guinea-pig ileum was examined using NADPH diaphorase histochemistry at the light microscopic level, and endothelial NOS immunohistochemistry at the light and electron microscopic level. The pattern of staining observed following NADPH diaphorase histochemistry and endothelial NOS immunohistochemistry was identical. Endothelial cells of the arterioles, capillaries and venules showed small patches of intense, perinuclear staining. Under the electron microscope, endothelial NOS immunoreactivity was found predominantly in association with the Golgi apparatus and with the membranes of some vesicles. Small regions of the plasma membrane and the rough endoplasmic reticulum also showed some immunoreactivity. The presence of NOS in the Golgi apparatus and in vesicles raises the possibility that NOS may be exteriorized by endothelial cells, and hence that nitric oxide is synthesized extracellularly.

Temperature dependency of the frequency and level of a spontaneous otoacoustic emission during fever

Using a method of heterodyne mixing with display of beats on a chart recorder, measurements were made of the frequency and level of a spontaneous otoacoustic emission in a human subject on 17 occasions during a period of 13 consecutive days. Temperature measurement was obtained with a thermometer measuring infra-red radiation from the ear-drum, indicative of body core temperature. In the latter half of this period there was variation of body set point temperature due to fever, and it was found that there was clear evidence of inverse relationship between temperature and both the frequency and level of the emission. The occurrence of fever was due to simple urinary tract infection and was considered to be without ototoxic implication; there was no associated worsening of pure tone threshold nor change in measurements of middle ear function.