The impact of noise in the operating theatre: a review of the evidence

INTRODUCTION

Noise has been recognised to have a negative impact on performance and wellbeing in many settings. Average noise levels have been found to range between 51dB and 79dB in operating theatres. Despite these levels of noise, there is little research investigating their effect on surgical team functioning.

METHODS

A literature review to look at the impact of noise in the operating theatre was performed on MEDLINE, which included the search terms 'noise' OR 'distraction' AND 'technical skill' OR 'Surgical skill' OR 'Operating Room'. Only 10 of 307 articles identified were deemed relevant.

FINDINGS

Eight of ten studies found noise to be detrimental to communication and surgical performance, particularly regarding total errors and time to task completion. No studies found noise to be beneficial. Two studies found case-irrelevant verbal communication to be a frequent form of noise pollution in operating theatres; this is both perceived by surgeons to be distracting and delays patient care.

CONCLUSION

Noise and irrelevant verbal communications were both found to be harmful to surgical performance, surgeon experience and team functioning.

Impact of COVID-19 on UK radiology training: a questionnaire study

AIM

To understand the impact of COVID-19 on radiology trainee experience and well-being.

MATERIALS AND METHODS

A questionnaire designed to capture the impact of COVID-19 on radiology training, working patterns, and well-being was sent to all speciality trainees in a regional UK radiology school. The survey was distributed at the beginning of May 2020 and responses collected over 2 weeks. Trainees were questioned about changes that had occurred over a time period starting at the beginning of the COVID-19 pandemic. All survey responses (n=29) were anonymised and the results were subsequently analysed.

RESULTS

Sixty-two percent (29 of 47) of trainees within the deanery, who were spread across seven different hospital sites, responded to the questionnaire. All trainees felt that overall radiology workload had decreased in response to COVID-19. Seventy-two percent (21/29) stated that their workload had significantly decreased. Seventy percent (19/27) reported decreased subspecialty experience, and 19% (5/27) reported a complete lack of subspecialty training. Twenty-four percent (7/29) of trainees were redeployed from radiology to clinical ward-based work. Forty-eight percent reported experiencing a worsening in their well-being compared to before the pandemic.

CONCLUSION

The first wave of the COVID-19 pandemic had a significant impact on training and well-being. Lessons learnt from this report should help prepare for a second-wave of COVID-19 or future pandemics.

Enhanced ubiquitin-dependent degradation by Nedd4 protects against α-synuclein accumulation and toxicity in animal models of Parkinson's disease

Parkinson's disease is a neurodegenerative disorder, characterized by accumulation and misfolding of α-synuclein. Although the level of α-synuclein in neurons is fundamentally linked to the onset of neurodegeneration, multiple pathways have been implicated in its degradation, and it remains unclear which are the critical ubiquitination enzymes that protect against α-synuclein accumulation in vivo. The ubiquitin ligase Nedd4 targets α-synuclein to the endosomal-lysosomal pathway in cultured cells. Here we asked whether Nedd4-mediated degradation protects against α-synuclein-induced toxicity in the Drosophila and rodent models of Parkinson's disease. We show that overexpression of Nedd4 can rescue the degenerative phenotype from ectopic expression of α-synuclein in the Drosophila eye. Overexpressed Nedd4 in the Drosophila brain prevented the α-synuclein-induced locomotor defect whereas reduction in endogenous Nedd4 by RNAi led to worsening motor function and increased loss of dopaminergic neurons. Accordingly, AAV-mediated expression of wild-type but not the catalytically inactive Nedd4 decreased the α-synuclein-induced dopaminergic cell loss in the rat substantia nigra and reduced α-synuclein accumulation. Collectively, our data in two evolutionarily distant model organisms strongly suggest that Nedd4 is a modifier of α-synuclein pathobiology and thus a potential target for neuroprotective therapies.

Unusual case of abdominal pain following liver transplant: causality or casualty?

This is an unusual case of chronic abdominal pain following two liver transplants with at least three potential causes: traumatic neuroma, intussusception of the small bowel of the Roux loop and biliary cast. Surgical removal of the latter two factors led to resolution of the pain. The management of the clinical case is discussed.

Vascular invasion in hepatocellular carcinoma: is there a correlation with MRI?

OBJECTIVE

Hepatocellular carcinoma (HCC) is one of the commonest malignancies worldwide. Prognosis is predicted by size at diagnosis, vascular invasion and tumour proliferation markers. This study investigates if MRI features of histologically proven HCCs correlate with vascular invasion.

METHODS

Between 2006 and 2008, 18 consecutive patients, with a total of 27 HCCs, had comprehensive MRI studies performed at our institution within a median of 36 days of histology sampling. Each lesion was evaluated independently on MRI by 3 radiologists (blinded to both the radiology and histopathology reports) using a 5-point confidence scale for 23 specific imaging features. The mean of the rating scores across readers was calculated to determine interobserver consistency. The most consistent features were then used to examine the value of features in predicting vascular invasion, using a χ(2 )test for trend, having eliminated those features without sufficient variability.

RESULTS

22 of the 23 imaging features showed sufficient variability across lesions. None of these significantly correlated with the presence of vascular invasion, although a trend was identified with the presence of washout in the portal venous phase on MRI and the median size of lesions, which was greater with vascular invasion.

CONCLUSION

This study suggests that no single MRI feature accurately predicts the presence of vascular invasion in HCCs, although a trend was seen with the presence of washout in the portal venous phase post gadolinium. Larger prospective studies are required to investigate this further.

Effect of Roux-en-Y surgery and medical intervention on Barrett's-type changes: an in vivo model

In animal models, mixed acid and bile reflux into lower esophagus induces histological changes comparable to Barrett's metaplasia (BM) and neoplasia. The aim of this study was to compare the effects of Roux-en-Y (REY) surgery and medical therapy on BM in animals before the development of neoplasia. Vagus preserving esophagojejunostomy operation was performed on Sprague-Dawley rats to achieve gastroduodenal reflux (GDR) into the esophagus in 30 animals. After 3 months, changes were reversed in 10 animals (Group REY) by REY operation, 10 animals (Group proton pump inhibitor [PPI]) were given PPI during the postoperative period, and 10 animals (Group GDR) did not have further intervention. At 4 months, histological examination of the lower esophagus was performed by an experienced pathologist. Physiological parameters were also analyzed in all animals preoperatively and at 4 months postoperatively. The length of columnar mucosa, degree of acute inflammation, degree of metaplasia, and composite BM score were significantly reduced by REY surgery compared with medical therapy and with control (columnar mucosa in cm [mean +/- standard error of the mean] Group REY 0.44 +/- 0.06, Group PPI 0.92 +/- 0.08, P < 0.001/Group GDR 1.17 +/- 0.31, P < 0.03). There was no neoplasia seen in any specimen. At 4 months, postoperatively controls Group REY surgery showed significantly more normalization of physiological parameters to preoperative levels than Group PPI (P < 0.05). REY surgery is potentially more beneficial than medical therapy in reversing the histological and biochemical changes of Barrett's esophagus due to GDR.

Angiogenesis in anal warts, anal intraepithelial neoplasia and anal squamous cell carcinoma

INTRODUCTION

Most cases of anal carcinoma seem to develop from high grade anal intraepithelial neoplasia (AIN) caused by persistent anal warts. Similar pre-invasive epithelial genital lesions (e.g. those of the cervix and vulva) have been shown to be associated with increased angiogenesis. In this study we examined biopsies of anal lesions ranging from warts to invasive anal carcinoma, with the aim of assessing the degree of angiogenesis in pre-invasive anal lesions.

METHOD

Samples from 70 patients (51 male) who had undergone excision biopsy or resection of anal wart lesions (20), low grade AIN (12), high grade AIN (27) and anal squamous cell carcinoma (SCC) (11) were studied. Samples (6) from normal HIV-anal skin were used as controls. The samples were stained for von Willebrand factor, a specific marker of endothelial cells. Angiogenesis was measured by microvessel density (MVD) analysis, quantifying the microvessels in the stroma adjacent to the epithelial lesion.

RESULTS

There was a statistically significant (P < 0.001) progressive increase in MVD between low grade AIN, high grade AIN and anal SCC. The difference in MVD between normal skin, warts and low grade AIN was not statistically significant.

CONCLUSION

There are progressive abnormal patterns of angiogenesis in highly dysplastic lesions, similar to those found in cervical and vulvar pathology. These findings may have biological, prognostic and therapeutic implications.

Focal nodular hyperplasia-like areas in cirrhosis

AIMS

Focal nodular hyperplasia-like lesions have rarely been described in cirrhotic livers. We describe five cases of such lesions.

METHODS AND RESULTS

Between 1998 and 2001, 146 liver transplants were performed at the Royal Free Hospital for cirrhosis of the liver. Nodular lesions identified in the livers removed at transplantation were defined histologically according to the International Working Party classification (Hepatology 1995; 22; 983). They were present in 63 of these livers, as follows: 36 dysplastic nodules, 121 macroregenerative nodules, and 71 hepatocellular carcinomas. In five patients, an additional 12 nodules (size range 4-23 mm, median 10.5 mm) showed histological features suggestive of focal nodular hyperplasia including mildly inflamed vascular fibrous septa, and ductular proliferation. Pre-transplantation imaging showed features suspicious for hepatocellular carcinoma, in three of these lesions (12, 23 and 23 mm diameter) from two different patients. These lesions were histologically indistinguishable from focal nodular hyperplasia occurring in non-cirrhotic livers, with fibrous scars and septa which contained vascular and ductular structures.

CONCLUSIONS

It is important to recognize that these lesions may occur in the context of cirrhosis and that they should be considered in the differential diagnosis with hepatocellular carcinoma, dysplastic nodules and macroregenerative nodules.

Small intestinal enteropathy with epithelial IgG and complement deposition in children with regressive autism

We have reported lymphocytic colitis in children with regressive autism, with epithelial damage prominent. We now compare duodenal biopsies in 25 children with regressive autism to 11 with coeliac disease, five with cerebral palsy and mental retardation and 18 histologically normal controls. Immunohistochemistry was performed for lymphocyte and epithelial lineage and functional markers. We determined the density of intraepithelial and lamina propria lymphocyte populations, and studied mucosal immunoglobulin and complement C1q localisation. Standard histopathology showed increased enterocyte and Paneth cell numbers in the autistic children. Immunohistochemistry demonstrated increased lymphocyte infiltration in both epithelium and lamina propria with upregulated crypt cell proliferation, compared to normal and cerebral palsy controls. Intraepithelial lymphocytes and lamina propria plasma cells were lower than in coeliac disease, but lamina propria T cell populations were higher and crypt proliferation similar. Most strikingly, IgG deposition was seen on the basolateral epithelial surface in 23/25 autistic children, co-localising with complement C1q. This was not seen in the other conditions. These findings demonstrate a novel form of enteropathy in autistic children, in which increases in mucosal lymphocyte density and crypt cell proliferation occur with epithelial IgG deposition. The features are suggestive of an autoimmune lesion.

Colonic CD8 and gamma delta T-cell infiltration with epithelial damage in children with autism

OBJECTIVES

We have reported colitis with ileal lymphoid nodular hyperplasia (LNH) in children with regressive autism. The aims of this study were to characterize this lesion and determine whether LNH is specific for autism.

METHODS

Ileo-colonoscopy was performed in 21 consecutively evaluated children with autistic spectrum disorders and bowel symptoms. Blinded comparison was made with 8 children with histologically normal ileum and colon, 10 developmentally normal children with ileal LNH, 15 with Crohn's disease, and 14 with ulcerative colitis. Immunohistochemistry was performed for cell lineage and functional markers, and histochemistry was performed for glycosaminoglycans and basement membrane thickness.

RESULTS

Histology demonstrated lymphocytic colitis in the autistic children, less severe than classical inflammatory bowel disease. However, basement membrane thickness and mucosal gamma delta cell density were significantly increased above those of all other groups including patients with inflammatory bowel disease. CD8(+) density and intraepithelial lymphocyte numbers were higher than those in the Crohn's disease, LNH, and normal control groups; and CD3 and plasma cell density and crypt proliferation were higher than those in normal and LNH control groups. Epithelial, but not lamina propria, glycosaminoglycans were disrupted. However, the epithelium was HLA-DR(-), suggesting a predominantly T(H)2 response.

INTERPRETATION

Immunohistochemistry confirms a distinct lymphocytic colitis in autistic spectrum disorders in which the epithelium appears particularly affected. This is consistent with increasing evidence for gut epithelial dysfunction in autism.

Inadvertent diclofenac rechallenge from generic and non-generic prescribing, leading to liver transplantation for fulminant liver failure

This case report describes fulminant hepatic failure in a 53-year-old female caused by inadvertent rechallenging with diclofenac, treated by orthotopic liver transplantation. The case also illustrates the hazards of using both generic and non-generic drug prescribing, with drugs that are known to be toxic. The literature on non-steroidal anti-inflammatory drugs and hepatoxicity is reviewed.

A pilot study of N-acetyl glucosamine, a nutritional substrate for glycosaminoglycan synthesis, in paediatric chronic inflammatory bowel disease

BACKGROUND

The breakdown of glycosaminoglycans is an important consequence of inflammation at mucosal surfaces, and inhibition of metalloprotease activity may be effective in treating chronic inflammation.

AIM

To report an alternative approach, using the nutriceutical agent N-acetyl glucosamine (GlcNAc), an amino-sugar directly incorporated into glycosaminoglycans and glycoproteins, as a substrate for tissue repair mechanisms.

METHODS

GlcNAc (total daily dose 3-6 g) was administered orally as adjunct therapy to 12 children with severe treatment-resistant inflammatory bowel disease (10 Crohn's disease, 2 ulcerative colitis). Seven of these children suffered from symptomatic strictures. In addition, similar doses were administered rectally as sole therapy in nine children with distal ulcerative colitis or proctitis resistant to steroids and antibiotics. Where pre- and post-treatment biopsies were available (nine cases), histochemical assessment of epithelial and matrix glycosaminoglycans and GlcNAc residues was made.

FINDINGS

Eight of the children given oral GlcNAc showed clear improvement, while four required resection. Of the children with symptomatic Crohn's stricture, only 3 of 7 have required surgery over a mean follow-up of > 2.5 years, and endoscopic or radiological improvement was detected in the others. Rectal administration induced remission in two cases, clear improvement in three and no effect in two. In all cases biopsied there was evidence of histological improvement, and a significant increase in epithelial and lamina propria glycosaminoglycans and intracellular GlcNAc.

CONCLUSIONS

GlcNAc shows promise as an inexpensive and nontoxic treatment in chronic inflammatory bowel disease, with a mode of action which is distinct from conventional treatments. It may have the potential to be helpful in stricturing disease. However, controlled trials and an assessment of enteric-release preparations are required to confirm its efficacy and establish indications for use.

Multicentre randomized placebo-controlled trial of ursodeoxycholic acid with or without colchicine in symptomatic primary biliary cirrhosis

AIM

To establish the efficacy of combination therapy with ursodeoxycholic acid (UDCA) and colchicine in patients with symptomatic primary biliary cirrhosis (PBC), defined by the presence of liver cirrhosis, pruritus or bilirubin exceeding 2 mg/mL.

METHODS

A total of 90 patients were randomly assigned to ursodeoxycholic acid 500 mg/daily plus placebo (UDCA group, n=44), or ursodeoxycholic acid at the same dosage plus colchicine, 1 mg/daily (UDCA/C group, n=46). The two groups were comparable for age, sex, stage of disease, severity of pruritus, bilirubin, and Mayo score. All patients underwent clinical, ultrasonographic, and biochemical examinations at entry and then every 6 months up to 3 years of follow-up. Patients with cirrhosis underwent endoscopy every 12 months. In a sub-group of patients without cirrhosis, who consented, liver biopsy was repeated at the end of the study.

RESULTS

The number of treatment failures (i.e. dead, orthotopic liver transplantation (OLT), complications of cirrhosis, doubling of bilirubin, untreatable pruritus) was 11 (25%) in the UDCA group and four (9%) in the UDCA/C group (P < 0.05). No significant differences were observed in terms of improvement of liver enzymes related to cholestasis and cytolysis and of amelioration of pruritus. The Mayo score values increased less above the baseline values at 24 and 36 month-intervals in the UDCA/C group than in the UDCA group. Histological evaluation at baseline and at the end of the study was available for 15 patients with pre-cirrhotic stage. A significant reduction in histological grading score was observed in patients from the UDCA/C group, whereas no changes in these histological scores were observed in the UDCA group.

CONCLUSIONS

The addition of colchicine to ursodeoxycholic acid in patients with symptomatic primary biliary cirrhosis results in a small but significant reduction of disease progress.

Human herpesviruses 6 and 7 as potential pathogens after liver transplant: prospective comparison with the effect of cytomegalovirus

Because cytomegalovirus (CMV) is an important opportunistic infection after liver transplant, we conducted a prospective study to see if the same applied to human herpesviruses (HHV)-6 and -7. We used polymerase chain reaction (PCR) methods optimised to detect active, not latent, infection and studied patients not receiving antiviral prophylaxis for CMV. Post-transplant, 536 blood samples were tested by PCR (median 7; range 4-50). Active infection with CMV was detected in 28/60 (47%), HHV-6 in 19/60 (32%), and HHV-7 in 29/60 (48%) of patients. The PCR-positive samples were tested by quantitative-competitive PCR to measure the virus load of each betaherpesvirus. The median peak virus load for CMV was significantly greater than that for HHV-6 or HHV-7. Detailed clinicopathological analyses for the whole population showed that CMV and HHV-6 were each significantly associated with biopsy-proven graft rejection. Individual case histories suggested that HHV-6 and HHV-7 may be the cause of some episodes of hepatitis and pyrexia. It is concluded that HHV-6 is a previously unrecognized contributor to the morbidity of liver transplantation, that HHV-7 may also be important and that both viruses should be included in the differential diagnosis of graft dysfunction.

Low-dose intravenous azathioprine may be effective in the management of acute fulminant colitis complicating inflammatory bowel disease

BACKGROUND

The management of acute fulminant colitis unresponsive to intravenous steroids is usually surgical. However, recent evidence suggests that intravenous administration of azathioprine at very high doses may allow more rapid onset of clinical efficacy, although its use has not previously been reported in the emergency situation.

AIM

To report the successful use of intravenous azathioprine in the management of acute fulminant colitis complicating both Crohn's disease and ulcerative colitis.

METHOD

We initially used intravenous azathioprine because of the refusal of the family of the first patient to accept surgery following failure of conventional medical management. Importantly the azathioprine was successful at the low dose of 3 mg/kg.day, equivalent to standard oral doses. Two subsequent patients demonstrated a similar resolution. All were weaned successfully to oral azathioprine and have remained in long-term endoscopic and histological remission.

CONCLUSION

These preliminary data suggest that low-dose intravenous azathioprine may be helpful adjunct therapy in selected cases of severe fulminant colitis. However, the need for close monitoring and daily surgical assessment remains paramount, and a formal trial of low-dose intravenous azathioprine is required before it may be more widely recommended.

Hypoosmolarity induces an increase of extracellular N-acetylaspartate concentration in the rat striatum

We previously showed that extracellular levels of N-acetylaspartate (NAA) increase when a medium with reduced NaCl concentration is perfused through a microdialysis probe, and proposed that NAA may be released during hypoosmotic swelling. Here, we demonstrate that this effect is due to hypoosmolarity of the perfusion medium, and not to low NaCl. NAA changes in the dialysate were compared with those of taurine as the osmoregulatory role of this amino acid is established. Reduction of the NaCl concentration in the perfusion medium increased the dialysate levels of NAA and taurine, but this effect was abolished when NaCl was replaced by sucrose to maintain isosmolarity. The NAA response to hypoosmolarity was smaller than that of taurine, but it may still be important to neurons as NAA is predominantly neuronal in the mammalian CNS.

Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children

BACKGROUND

We investigated a consecutive series of children with chronic enterocolitis and regressive developmental disorder.

METHODS

12 children (mean age 6 years [range 3-10], 11 boys) were referred to a paediatric gastroenterology unit with a history of normal development followed by loss of acquired skills, including language, together with diarrhoea and abdominal pain. Children underwent gastroenterological, neurological, and developmental assessment and review of developmental records. Ileocolonoscopy and biopsy sampling, magnetic-resonance imaging (MRI), electroencephalography (EEG), and lumbar puncture were done under sedation. Barium follow-through radiography was done where possible. Biochemical, haematological, and immunological profiles were examined.

FINDINGS

Onset of behavioural symptoms was associated, by the parents, with measles, mumps, and rubella vaccination in eight of the 12 children, with measles infection in one child, and otitis media in another. All 12 children had intestinal abnormalities, ranging from lymphoid nodular hyperplasia to aphthoid ulceration. Histology showed patchy chronic inflammation in the colon in 11 children and reactive ileal lymphoid hyperplasia in seven, but no granulomas. Behavioural disorders included autism (nine), disintegrative psychosis (one), and possible postviral or vaccinal encephalitis (two). There were no focal neurological abnormalities and MRI and EEG tests were normal. Abnormal laboratory results were significantly raised urinary methylmalonic acid compared with age-matched controls (p=0.003), low haemoglobin in four children, and a low serum IgA in four children.

INTERPRETATION

We identified associated gastrointestinal disease and developmental regression in a group of previously normal children, which was generally associated in time with possible environmental triggers.

Enteropathy in Zambians with HIV related diarrhoea: regression modelling of potential determinants of mucosal damage

BACKGROUND

AIDS is characterised by small intestinal mucosal damage, but its aetiopathogenesis is poorly understood. Enteric infections in Africa differ from those in northern countries, where protozoan infections have been associated with severe enteropathy in AIDS patients.

AIMS

To characterise enteropathy in Zambian AIDS patients compared with local controls, and to assess relative contributions of enteric infection, nutritional impairment, and immune dysfunction.

METHODS

Computer aided mucosal morphometry of small intestinal biopsy specimens from 56 HIV infected Zambians with persistent diarrhoea and 26 diarrhoea free controls, followed by regression modelling.

RESULTS

Patients with HIV related diarrhoea had reduced villous height and increased crypt depth compared with controls. There was no difference between HIV positive and negative controls. In regression models applied to AIDS mucosal measurements, villous height and crypt depth were related to nutritional parameters and to serum soluble tumour necrosis factor receptor p55 concentration. Crypt depth was also related to lamina propria plasma cell count. Intestinal infection was found in 79%, which consisted predominantly of microsporidia in 34%, Isospora belli in 24%, and Cryptosporidium parvum in 21%, but detection of these enteropathogens was not related to severity of enteropathy.

CONCLUSIONS

Nutritional and immune disturbances were associated with enteropathy, accounting for over one third of the variation in mucosal morphometric parameters.

Brain tissue acidosis: effects on the extracellular concentration of N-acetylaspartate

N-Acetylaspartate (NAA) is characterized by a high tissue-to-extracellular concentration ratio under normal conditions and is released from neurons during hypoosmotic cell swelling. As cell volume regulation and acid-base homeostasis share common processes, we have examined by microdialysis whether the extracellular concentration of NAA is altered by various acidotic challenges. Twenty-minute perfusion of 50 mM NH4+ through the microdialysis probe progressively lowered dialysate pH by 0.18, followed by a sudden, additional reduction after NH4+ removal. The latter effect indicated extrusion of cellular H+ because it was suppressed by blockade of Na+/H+ exchange with 5-(N,N-dimethyl)amiloride (1 or 5 mM in perfusion medium). NH4+ increased dialysate levels of NAA and lactate by approximately two- and threefold their initial values, respectively. These data demonstrate that pronounced intracellular acidosis is associated with NAA efflux, presumably from neurons. Whether this effect is linked directly to acid-base homeostasis or is secondary to acidosis-induced cell swelling remains to be clarified. Hypercapnia and perfusion of acid medium failed to increase dialysate NAA, probably because acidosis was not severe enough or the associated cellular swelling was not followed by regulatory volume decrease. As cellular swelling and acidosis are key features of cerebral ischaemia, further investigations into the role of NAA, and the development of sophisticated magnetic resonance spectroscopic methods capable of resolving intra-/extracellular NAA redistribution, would be especially relevant to clinical practice.

Histopathological aspects of viral hepatitis

The main method of classification of chronic viral hepatitis is now by cause, and the old histology-based classification is no longer considered appropriate. However, liver biopsy remains an important part of patient assessment and, in the context of clinical trials, biopsy findings are often scored in a semiquantitative manner. The concepts of grading and staging, borrowed from tumour pathology, have been introduced, representing the severity of the necroinflammatory lesion and the extent of its structural consequences respectively. The pathology of the individual forms of viral hepatitis A to G shows more similarities than differences. However, some pathological features are commonly associated with specific viruses. The combination of portal lymphoid follicles, bile duct damage, lobular activity and steatosis give chronic hepatitis C a characteristic histological profile. Very similar appearances have been noted in the limited number of biopsies so far reported from patients with known combined hepatitis C and G virus infection.

Investigation into the role of N-acetylaspartate in cerebral osmoregulation

Marked abnormalities of the magnetic resonance intensity of N-acetylaspartate (NAA) have been reported in patients with various neurological disorders, but the neurochemical consequences of these alterations are difficult to assess because the function of NAA remains speculative. The purpose of this study was to examine whether NAA plays a role in protecting neurons against osmotic stress. Intracerebral microdialysis was used to expose a small region of the rat dorsolateral striatum to an increasingly hyposmotic environment and to measure resulting changes in NAA extracellular concentrations. NAA changes in the extracellular fluid (ECF) were compared with those of the amino acids, in particular, taurine, known to be involved in brain osmoregulation. Stepped increases in cellular hydration produced by hyposmotic perfusion media induced a marked increase in ECF NAA, reflecting a redistribution of NAA from intra-to extracellular space. Parallel experiments showed that, of all the extracellular amino acids measured, only taurine markedly increased with hyposmolar perfusion medium, indicating that the ECF NAA increase associated with hyposmotic stress was a specific response and not passive leakage out of the cells. As NAA is predominantly neuronal, it may contribute to the protection of neurons against swelling (i.e., regulatory volume decrease). In conditions with impaired blood-brain barrier and cytotoxic oedema, efflux of intracellular NAA subsequent to sustained cellular swelling might lead to a reduction in total brain NAA detectable by magnetic resonance spectroscopy. Alternatively, redistribution of NAA from intra-to extracellular space implies changes in its chemical environment that may alter its magnetic resonance visibility.

High resolution proton NMR spectroscopy of multiple sclerosis lesions

Tissue from postmortem multiple sclerosis and normal control brains was extracted with perchloric acid and analysed using proton NMR spectroscopy. The content of N-acetyl-derived groups (the sum of N-acetyl-aspartate, acetate, and N-acetylaspartylglutamate) was decreased in multiple sclerosis plaques compared with normal control white matter (mean, 4.36 vs. 6.64 mumol/g wet weight). In normal appearing white matter adjacent to plaques a corresponding decrease was seen, with no change in white matter distant from plaques. A decrease in the content of total creatine was observed in multiple sclerosis plaques in comparison with normal control white matter (mean, 4.64 vs. 6.56 mumol/g wet weight), which correlated strongly with the decrease in N-acetyl-derived groups. No changes in other metabolites such as total choline or myo-inositol were seen. The decreases in content of N-acetyl-derived groups are in agreement with observations from in vivo proton NMR spectroscopy in multiple sclerosis patients. The decrease in total creatine is in contrast to most of the observations made in vivo where total creatine is assumed to be unchanged and metabolite levels are often expressed as a total creatine ratio. The use of a total creatine ratio in vivo could lead to an underestimation of reductions in N-acetylaspartate and an apparent increase in other metabolites in the multiple sclerosis lesion.

Depletion of brain glutathione is accompanied by impaired mitochondrial function and decreased N-acetyl aspartate concentration

The effect of depletion of reduced glutathione (GSH) on brain mitochondrial function and N-acetyl aspartate concentration has been investigated. Using pre-weanling rats, GSH was depleted by L-buthionine sulfoximine administration for up to 10 days. In both whole brain homogenates and purified mitochondrial preparations complex IV (cytochrome c oxidase) activity was decreased, by up to 27%, as a result of this treatment. In addition, after 10 days of GSH depletion, citrate synthase activity was significantly reduced, by 18%, in the purified mitochondrial preparations, but not in whole brain homogenates, suggesting increased leakiness of the mitochondrial membrane. The whole brain N-acetyl aspartate concentration was also significantly depleted at this time point, by 11%. It is concluded that brain GSH is important for the maintenance of optimum mitochondrial function and that prolonged depletion leads also to loss of neuronal integrity. The relevance of these findings to Parkinson's disease and the inborn errors of glutathione metabolism are also discussed.

Effects of 1-methyl-4-phenylpyridinium on isolated rat brain mitochondria: evidence for a primary involvement of energy depletion

The effects of 1-methyl-4-phenylpyridinium (MPP+) on the oxygen consumption, ATP production, H2O2 production, and mitochondrial NADH-CoQ1 reductase (complex I) activity of isolated rat brain mitochondria were investigated. Using glutamate and malate as substrates, concentrations of 10-100 microM MPP+ had no effect on state 4 (-ADP) respiration but decreased state 3 (+ADP) respiration and ATP production. Incubating mitochondria with ADP for 30 min after loading with varying concentrations of MPP+ produced a concentration-dependent decrease in H2O2 production. Incubation of mitochondria with ADP for 60 min after loading with 100 microM MPP+ caused no loss of complex I activity after washing of MPP+ from the mitochondrial membranes. These data are consistent with MPP+ initially binding specifically to complex I and inhibiting both the flow of reducing equivalents and the production of H2O2 by the mitochondrial respiratory chain, without irreversibly damaging complex I. However, mitochondria incubated with H2O2 in the presence of Cu2+ ions showed decreased complex I activity. This study provides additional evidence that cellular damage initiated by MPP+ is due primarily to energy depletion caused by specific binding to complex I, any increased damage due to free radical production by mitochondria being a secondary effect.

Extracellular N-acetylaspartate in the rat brain: in vivo determination of basal levels and changes evoked by high K+

The purpose of this study was to determine the extracellular concentrations of N-acetylaspartate (NAA) in the rat cerebral cortex, striatum, and hippocampus of halothane-anaesthetised rats by intracerebral microdialysis, and to examine the effects of high K(+)-induced local depolarisation, which provokes synchronous neurotransmitter release, cell swelling, and acid-base changes. Basal levels of NAA in the extracellular fluid (ECF) were determined by the zero net flux method. Tissue levels of NAA in the cortex, striatum, and hippocampus were 8.4, 5.7, and 7.2 mmol/kg, respectively. The corresponding extracellular concentrations of NAA were much lower (35.1, 83.7, and 23.0 microM). High tissue/ECF concentration ratios may suggest little release or leakage of NAA under basal conditions, and potent reuptake mechanisms for NAA in the cellular membrane of CNS cells. There was no change in ECF NAA during K(+)-induced local depolarising stimuli produced in the striatum, but NAA levels consistently increased after the K+ stimuli, irrespective of whether or not Ca2+ was present in the perfusion medium. These data confirm that NAA is not a neurotransmitter and suggest strongly that NAA is not directly involved in the release and reuptake or metabolism of neuroactive compounds. The increase of NAA in the ECF immediately after K+ stimulation may reflect an involvement in brain osmoregulation and/or acid-base homeostasis.

CT of microcystic (serous) pancreatic adenoma

Although microcystic adenoma of the pancreas is well recognised as a benign tumour, it is often treated surgically. We present serial CT over 9 years of a patient with this tumour that demonstrated a substantial rate of growth and the development of pathognomonic features.

Evidence that hepatitis D virus needs hepatitis B virus to cause hepatocellular damage

Serial liver biopsy specimens from 11 patients who had liver transplants after hepatitis D virus (HDV)-related end-stage liver disease developed were examined, allowing a novel opportunity to study the evolution of HDV infection in relation to hepatitis B virus (HBV) infection from the earliest stages. Hepatitis D virus antigen was detected in liver tissue in the absence of either tissue or serologic evidence of HBV recurrence within 3 months in all eight patients biopsied at that time. After serologic evidence of recurrent HBV infection in nine patients, there was a massive increase in hepatic expression of hepatitis D virus antigen and this was associated with the transient appearance of serum hepatitis D virus antigen in four patients. Coexpression of both HBV and HDV antigens in the liver was associated with the onset of lobular hepatitis, which progressed to chronic hepatitis in five patients. These findings indicate that HDV can survive and synthesize HDAg in the absence of detectable HBV, but when HBV replication increased to a detectable level, HDV replication was enhanced massively. Contrary to current thinking, the data suggest that HDV is not directly cytopathic and that HBV is an essential cofactor in the evolution of hepatocellular damage.

Localization of cytochrome P-450 gene expression in normal and diseased human liver by in situ hybridization of wax-embedded archival material

The localization of the expression of several cytochrome P-450 genes in normal and diseased human liver was investigated by in situ hybridization of formalin-fixed, paraffin wax-embedded archival tissue samples with 35S-labeled antisense RNA probes. The results demonstrated that genes coding for members of the cytochrome P-450 3A subfamily (CYP3A) were preferentially expressed in hepatocytes in acinar zone 3 (the centrilobular region), whereas genes coding for CYP1A2, CYP2A, 2B and 2C were expressed uniformly throughout the liver acinus. In cirrhotic livers, CYP2A and 2B genes (and to a lesser extent, CYP3A genes) were highly expressed in isolated hepatocytes located at the junction of parenchyma with fibrous septa. The cause and significance of the position-dependent expression of specific cytochrome P-450 genes in normal and diseased human liver are discussed.

Misuse of ecstasy

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Effects of overexpression of phosphofructokinase on glycolysis in the yeast Saccharomyces cerevisiae

The influence of 6-phosphofructo-1-kinase on glycolytic flux in the yeast Saccharomyces cerevisiae was assessed by measuring the effects of enzyme overexpression on glucose consumption, ethanol production, and glycolytic intermediate levels under aerobic and anaerobic conditions. Enzyme overexpression had no effect on glycolytic flux under anaerobic conditions, but under aerobic conditions, it increased glycolytic flux up to the anaerobic level. The Pasteur effect was thus abolished in these cells. The increased glycolytic flux was accompanied by a compensatory decrease in flux in oxidative phosphorylation. The concentrations of the enzyme substrates showed only small or insignificant changes. These data imply that the enzyme has a low flux control coefficient for glycolysis. However, in cells overexpressing the enzyme, there was a compensatory decrease in 6-phosphofructo-2-kinase activity which was accompanied by a corresponding decrease in fructose 2,6-bisphosphate concentration. Measurements in vitro showed that the decrease in the concentration of this positive allosteric effector of 6-phosphofructo-1-kinase could significantly lower its specific activity in the cell and that this could compensate for the increased enzyme concentration in the overproducer.

High-level expression of hepatitis B viral antigens in fibrosing cholestatic hepatitis

The expression of hepatitis B viral antigens was quantified in liver tissue from four transplant recipients with fibrosing cholestatic hepatitis (FCH) and compared with five other transplant recipients who did not develop this syndrome and 30 patients with chronic hepatitis B virus (HBV) infection. As measured by radioimmunoassays, the liver tissue from patients with FCH had significantly greater amounts of both hepatitis B surface antigen (HBsAg) and nucleocapsid antigens than to transplant patients without this syndrome (P less than 0.01) or patients with chronic HBV infection (P less than 0.001). Intrahepatic expression of pre-S1/pre-S2 in FCH was also extensive with a distribution parallel to that of HBsAg. High-level expression of intrahepatic HBsAg and hepatitis B core antigen in the explanted liver was associated with subsequent development of FCH in the liver graft, suggesting that viral/host factors may also be important. This pattern of intrahepatic hepatitis viral antigen expression, by analogy with Chisari's transgenic mice model and Roingeard's HBV-transfected HepG2 cell model, may be the cause of direct hepatocytopathic injury in this condition.

Hepatitis B virus reinfection after orthotopic liver transplantation. Serological and clinical implications

The implications of hepatitis B virus (HBV) reinfection after liver transplantation were studied in 29 patients followed for 1.7-15 years. Of 20 patients with HBV infection alone, nine were HBeAg and HBV DNA seronegative and 11 had evidence of HBV replication as measured by HBeAg or HBV DNA seropositivity. Nine patients had co-existing HBV and delta virus (HDV) infection. Five patients became HBsAg seronegative after transplantation (four immediately and one after an hepatitic episode). Of the 20 patients with HBV infection alone, 17 had evidence of viral replication after transplantation with markedly increased HBV DNA levels. Five patients with HDV infection had HBV DNA in serum, but in significantly lower amounts than in those with HBV infection alone. Twenty-five episodes of graft dysfunction attributed to recurrent HBV infection occurred in 19 patients (65.5%). Thirteen episodes (in 12 patients) were self-resolving acute hepatitic illnesses. Six patients had a rapidly progressive illness leading to graft loss within 6 weeks, with the distinctive histological features termed fibrosing cholestatic hepatitis (FCH). Liver function tests in these patients showed markedly abnormal serum bilirubin and prothrombin times, but only modest increases in serum transaminase levels. An additional six patients lost their graft as a consequence of HBV recurrence through various pathogenetic mechanisms including possible (but unproven) FCH, chronic active hepatitis or late-onset hepatic failure. Co-existing HDV infection appeared to confer some medium-term protection from graft loss.

Significance of serum IgM anti-HBc in chronic hepatitis B virus infection

Because of widely differing reports on the significance of IgM anti-HBc in chronic hepatitis B virus (HBV) infection, paired sera and liver biopsies from 49 patients with chronic HBV infection were analysed for serum IgM anti-HBc, HBsAg titre, HBeAg/anti-HBe, HBV DNA, serum aspartate transaminase, intrahepatic HBcAg expression, and liver histology. High levels of IgM anti-HBc, in the diagnostic range of acute hepatitis B (greater than 1.2), were detected in seven patients (14.3%) and a total of 34 patients (69.6%) had an index of more than 0.2. No correlation was found between IgM anti-HBc and the serum markers of active viral replication or HBsAg titre but it correlated significantly with intrahepatic expression of cytoplasmic HBcAg (r2 = 0.165, P = 0.002). IgM anti-HBc also correlated with active liver histology (P = 0.015) but there was a considerable overlap of the IgM anti-HBc index values between the various disease groups, indicating a poor specificity. Serial assessment of IgM anti-HBc in eight patients treated with interferon-alpha (four responders) showed an increase in IgM anti-HBc in three out of four patients corresponding to the e-seroconversion period followed by a drop in IgM anti-HBc levels. However, an increase in IgM anti-HBc was also seen in one non-responder, indicating that this feature is not unique to interferon-alpha responders. These data indicate that serum IgM anti-HBc cannot be used alone as a certain diagnostic measure of HBV replication nor in the prediction of liver histology.

Liver transplantation and hepatitis viruses

Considerations regarding liver transplantation in viral-hepatitis-related acute liver failure and end-stage chronic liver disease are discussed. Parameters of prognosis and indications for transplantation are presented. Differences according to the causative agent are noted, in particular regarding the danger of reinfection. The role of immunoprophylaxis is addressed as is the question of additional antiviral (interferon) treatment.

Carnitine therapy and metabolism in the disorders of propionyl-CoA metabolism studied using 1H-NMR spectroscopy

1H-NMR spectroscopy has been used to study metabolic perturbations in patients with disorders of propionyl-CoA metabolism during the administration of oral and intravenous L-carnitine. The administration of L-carnitine either in the form of a challenge or as a therapeutic measure resulted in an increased excretion of propionylcarnitine, consistent with the removal of accumulated intramitochondrial propionyl-CoA esters. Additionally, during the therapeutic administration of L-carnitine excretion of acetylcarnitine occurred, coincident with an improvement in clinical condition and confirming the intracellular propionyl-CoA depletion. An additional benefit from the formation of acylcarnitines may be an accompanying intracellular alkalinisation.

IgA class antibodies to hepatitis delta virus antigen in acute and chronic hepatitis delta virus infections

Sera from 31 patients with chronic hepatitis delta virus infection and 18 patients with acute hepatitis delta virus infection were examined for IgA class antibodies to this virus using a newly developed enzyme immunoassay. IgA antibody to hepatitis D virus was detected in 21 (67.7%) of 31 patients with chronic delta viral hepatitis, but in only 1 (5.6%) of the 18 patients with acute infection (p less than 0.0005). Of the 21 patients with chronic delta hepatitis with IgA antibody to hepatitis D virus, 19 (90.5%) had moderate-to-severe activity on liver biopsy: 18 of the 21 had histological features of chronic active hepatitis and three had chronic lobular hepatitis. In all, 23 patients with chronic delta hepatitis had moderate-to-severe activity, and 19 (82.6%) had IgA antibody to hepatitis D virus. No statistically significant correlations were found between IgA antibody to hepatitis D virus and biochemical markers of liver injury (p greater than 0.4), or the presence of hepatitis delta virus antigen in liver biopsies (p greater than 0.2), in the patients with chronic delta hepatitis. The finding that IgA antibody to hepatitis D virus was almost exclusively associated with chronic hepatitis delta virus infection and correlated independently with moderate-to-severe histological activity (with a specificity of 90.5% and a sensitivity of 82.6%) suggests that this antibody might be a useful serological marker of underlying liver damage in chronic delta hepatitis.

Export of intracellular HBsAg in chronic hepatitis B virus infection is related to viral replication

Serum and liver HBsAg bear an inverse relation to each other during the evolution of chronic hepatitis B virus infection and the quantity of HBsAg in tissue rises gradually with time. In this study, intracellular and extracellular levels of HBsAg were measured by radioimmunoassay in primary culture of hepatocytes from 30 patients with chronic hepatitis B virus infection to determine a possible relationship with hepatitis B virus replication. Serum levels of HBsAg correlated with markers of active viral replication (serum hepatitis B virus DNA, p less than 0.005, and tissue HBcAg, p less than 0.02) but inversely with tissue HBsAg (p less than 0.05). In similar fashion, in vitro export of HBsAg was also related to the presence of active viral replication markers (serum hepatitis B virus DNA, p less than 0.02, and tissue HBcAg, p less than 0.05) and negatively with tissue HBsAg (p less than 0.001). Export of HBeAg also correlated positively with markers of active viral replication (serum hepatitis B virus DNA, p less than 0.05 and tissue HBcAg, p less than 0.05). Further experiments indicated that intrahepatic pre-S1 and pre-S2 correlated closely with intrahepatic HBsAg, indicating that a failure to export HBsAg was unlikely to be attributable to deficient intracellular expression of pre-S1 or pre-S2. These data indicate that in vitro primary hepatocyte culture of hepatitis B virus-infected cells provides an accurate reflection of in vivo export of HBsAg and that this is closely related to the presence of active viral replication.

Urinary excretion of nitrogenous and non-nitrogenous compounds in the chronic ethanol-fed rat

1. The metabolic consequences of chronic ethanol feeding was investigated by assay of urinary metabolites. Male Wistar rats were fed a liquid diet containing 35% of total energy as ethanol or isovolumetric, isocaloric and isonitrogenous amounts of the same diet in which ethanol was substituted by isocaloric glucose (controls). 2. At 6 weeks the entire skeletal muscle mass was reduced by approximately 20%. The urinary excretion of nitrogen, urea and uric acid increased by between 23 and 128%. Urinary creatinine excretion was not significantly altered. 3. Urinary excretion of magnesium was significantly increased by 43%. Urinary excretion of sodium, potassium, calcium and phosphate was increased slightly (i.e. 5-22%), but this change was not statistically significant. 4. Proton n.m.r. spectroscopic analysis showed that ethanol feeding reduced the urinary excretion of citrate and 2-oxoglutarate (by approximately 50%), suggesting decreased citric acid cycle activity. There was an increased excretion of alanine (44%), but excretion of succinate and acetate was not significantly altered. Ethanol in the urine of ethanol-fed rats comprised approximately 2% of total ethanol intake and less than 1% of total energy intake. 5. Lactose was detectable in urine of ethanol-fed rats, but not in control rats, reflecting the reported decreased intestinal lactase activity and increased gut permeability in alcoholics. Urinary galactose excretion decreased by 41%, but relatively large increases in lactate excretion (50%) did not achieve statistical significance. 6. It was concluded that chronic ethanol feeding causes disturbances in whole-body nitrogen homoeostasis and alterations in intermediary metabolism.

Hepatic histological findings after transplantation for chronic hepatitis B virus infection, including a unique pattern of fibrosing cholestatic hepatitis

Long-term follow-up of 27 patients with hepatitis B virus-related chronic liver disease treated by transplantation showed that 23 had hepatitis B virus recurrence. In 13 patients late changes in the grafts were similar to those described in other series: minor abnormalities in five cases, chronic active hepatitis in five cases and non-hepatitis B virus-related graft dysfunction in three cases. Three patients had incomplete histological follow-up. Analysis of the histological changes and viral antigen expression in six cases revealed a distinct and novel pattern termed fibrosing cholestatic hepatitis. Development of fibrosing cholestatic hepatitis was associated with rapidly progressive graft dysfunction. It is postulated that this pattern of fibrosing cholestatic hepatitis develops because of a high cytoplasmic expression of viral antigens, including HBsAg. The remaining case had some features of fibrosing cholestatic hepatitis. The main histological features of this unique syndrome include thin, perisinusoidal bands of fibrosis extending from portal tracts to surround plates of ductular-type epithelium; prominent cholestasis; ground-glass transformation; and ballooning of hepatocytes with cell loss and mild mixed inflammatory reaction.

Hepatitis B virus related hepatocellular carcinoma in the non-cirrhotic liver

To complement investigations of hepatitis B virus infection in hepatocellular carcinoma associated with cirrhosis, we studied hepatitis B virus infection in 137 hepatoma patients without cirrhosis. Ninety-five were from the U.K. (where the prevalence of hepatitis B virus markers is very low) and 42 were from overseas. Of these 137 patients, seven (5%) were hepatitis B surface antigen seropositive. None of the hepatitis B surface antigen positive patients had any recognisable risk factors other than birth in an area of high hepatitis B virus prevalence in four of the patients. Of the 95 U.K. patients three (3%) were hepatitis B surface antigen positive as compared to a carriage rate of less than 0.1% in the normal population. The frequency of antibodies to hepatitis B surface and core antigens alone (both 7.5%) was also higher than that seen in the normal U.K. population (2.4%). Histological examination of the non-tumorous liver showed fine fibrous septa in three patients, more extensive subcapsular scars in one, chronic persistent hepatitis in two and non-specific inflammation in one. On immunohistochemical examination five patients had hepatitis B surface antigen (but not core antigen) detectable in the non-tumorous liver tissue. Hepatitis B virus infection appears to be a small, but significant, risk factor for the development of hepatoma in the non-cirrhotic group.

Creatine metabolism during metabolic perturbations in patients with organic acidurias

Creatine excretion was measured in two patients with methylmalonic aciduria and two patients with 3-hydroxy-3-methylglutaric aciduria. During periods of metabolic decompensation the creatine/creatinine ratio increased and fell during recovery. Prolonged periods of metabolic decompensation may result in the loss of a large proportion of the creatine pool. In one study, measurements of total daily urinary output of metabolites demonstrated that the absolute creatine excretion followed a similar qualitative pattern to the creatine/creatinine ratio. However, apparent fluctuations in methylmalonate excretion when expressed as methylmalonate/creatinine ratio were absent when absolute methylmalonate excretion was calculated. The increased creatine excretion during metabolic perturbations may result from loss from creatine containing tissues such as muscle and may represent an underlying defect in energy metabolism. Alternatively creatine transport may be disrupted by accompanying acidosis. The use of metabolite/creatinine ratios as a measure of metabolite excretion rates during metabolic decompensation whilst qualitatively sound may need a re-appraisal.