Peri-operative cardiac arrest in children as reported to the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest. An activity survey estimated UK paediatric anaesthesia annual caseload as 390,000 cases, 14% of the UK total. Paediatric peri-operative cardiac arrests accounted for 104 (12%) reports giving an incidence of 3 in 10,000 anaesthetics (95%CI 2.2-3.3 per 10,000). The incidence of peri-operative cardiac arrest was highest in neonates (27, 26%), infants (36, 35%) and children with congenital heart disease (44, 42%) and most reports were from tertiary centres (88, 85%). Frequent precipitants of cardiac arrest in non-cardiac surgery included: severe hypoxaemia (20, 22%); bradycardia (10, 11%); and major haemorrhage (9, 8%). Cardiac tamponade and isolated severe hypotension featured prominently as causes of cardiac arrest in children undergoing cardiac surgery or cardiological procedures. Themes identified at review included: inappropriate choices and doses of anaesthetic drugs for intravenous induction; bradycardias associated with high concentrations of volatile anaesthetic agent or airway manipulation; use of atropine in the place of adrenaline; and inadequate monitoring. Overall quality of care was judged by the panel to be good in 64 (62%) cases, which compares favourably with adults (371, 52%). The study provides insight into paediatric anaesthetic practice, complications and peri-operative cardiac arrest.

Forensic DNA Profiling: Legal and Ethical Considerations

Forensic DNA analysis is vital in criminal investigations, posing intricate legal and ethical dilemmas. This emphasises the need to balance DNA technology benefits with individual rights, prioritizing privacy, consent, and ethical practices. Stringent regulation of DNA data management is essential to prevent misuse and ensure privacy protection. Advances like probabilistic genotyping software improve interpretation accuracy, addressing complexities in mixture analysis. Responsible DNA use also requires navigating emerging technologies like next-generation sequencing while upholding ethical standards. Establishing transparency, accuracy, and ethical conduct throughout the analysis process is crucial for building public trust. Regulatory oversight and accountability mechanisms are necessary to address errors and maintain fairness in DNA data management. Through continuous dialogue and adherence to ethical standards, the forensic community can uphold scientific integrity and preserve public confidence in DNA analysis.

Fractal Electronics for Stimulating and Sensing Neural Networks: Enhanced Electrical, Optical, and Cell Interaction Properties

Imagine a world in which damaged parts of the body - an arm, an eye, and ultimately a region of the brain - can be replaced by artificial implants capable of restoring or even enhancing human performance. The associated improvements in the quality of human life would revolutionize the medical world and produce sweeping changes across society. In this chapter, we discuss several approaches to the fabrication of fractal electronics designed to interface with neural networks. We consider two fundamental functions - stimulating electrical signals in the neural networks and sensing the location of the signals as they pass through the network. Using experiments and simulations, we discuss the favorable electrical performances that arise from adopting fractal rather than traditional Euclidean architectures. We also demonstrate how the fractal architecture induces favorable physical interactions with the cells they interact with, including the ability to direct the growth of neurons and glia to specific regions of the neural-electronic interface.

Fractal Resonance: Can Fractal Geometry Be Used to Optimize the Connectivity of Neurons to Artificial Implants?

In parallel to medical applications, exploring how neurons interact with the artificial interface of implants in the human body can be used to learn about their fundamental behavior. For both fundamental and applied research, it is important to determine the conditions that encourage neurons to maintain their natural behavior during these interactions. Whereas previous biocompatibility studies have focused on the material properties of the neuron-implant interface, here we discuss the concept of fractal resonance - the possibility that favorable connectivity properties might emerge by matching the fractal geometry of the implant surface to that of the neurons.To investigate fractal resonance, we first determine the degree to which neurons are fractal and the impact of this fractality on their functionality. By analyzing three-dimensional images of rat hippocampal neurons, we find that the way their dendrites fork and weave through space is important for generating their fractal-like behavior. By modeling variations in neuron connectivity along with the associated energetic and material costs, we highlight how the neurons' fractal dimension optimizes these constraints. To simulate neuron interactions with implant interfaces, we distort the neuron models away from their natural form by modifying the dendrites' fork and weaving patterns. We find that small deviations can induce large changes in fractal dimension, causing the balance between connectivity and cost to deteriorate rapidly. We propose that implant surfaces should be patterned to match the fractal dimension of the neurons, allowing them to maintain their natural functionality as they interact with the implant.

The incidence of potentially serious complications during non-obstetric anaesthetic practice in the United Kingdom: an analysis from the 7th National Audit Project (NAP7) activity survey

Complications and critical incidents arising during anaesthesia due to patient, surgical or anaesthetic factors, may cause harm themselves or progress to more severe events, including cardiac arrest or death. As part of the 7th National Audit Project of the Royal College of Anaesthetists, we studied a prospective national cohort of unselected patients. Anaesthetists recorded anonymous details of all cases undertaken over 4 days at their site through an online survey. Of 416 hospital sites invited to participate, 352 (85%) completed the survey. Among 24,172 cases, 1922 discrete potentially serious complications were reported during 1337 (6%) cases. Obstetric cases had a high reported major haemorrhage rate and were excluded from further analysis. Of 20,996 non-obstetric cases, 1705 complications were reported during 1150 (5%) cases. Circulatory events accounted for most complications (616, 36%), followed by airway (418, 25%), metabolic (264, 15%), breathing (259, 15%), and neurological (41, 2%) events. A single complication was reported in 851 (4%) cases, two complications in 166 (1%) cases and three or more complications in 133 (1%) cases. In non-obstetric elective surgery, all complications were 'uncommon' (10-100 per 10,000 cases). Emergency (urgent and immediate priority) surgery accounted for 3454 (16%) of non-obstetric cases but 714 (42%) of complications with severe hypotension, major haemorrhage, severe arrhythmias, septic shock, significant acidosis and electrolyte disturbances all being 'common' (100-1000 per 10,000 cases). Based on univariate analysis, complications were associated with: younger age; higher ASA physical status; male sex; increased frailty; urgency and extent of surgery; day of the week; and time of day. These data represent the rates of potentially serious complications during routine anaesthesia care and may be valuable for risk assessment and patient consent.

Peri-operative cardiac arrest: epidemiology and clinical features of patients analysed in the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. Here we report the results of the 12-month registry, from 16 June 2021 to 15 June 2022, focusing on epidemiology and clinical features. We reviewed 881 cases of peri-operative cardiac arrest, giving an incidence of 3 in 10,000 anaesthetics (95%CI 3.0-3.5 per 10,000). Incidence varied with patient and surgical factors. Compared with denominator survey activity, patients with cardiac arrest: included more males (56% vs. 42%); were older (median (IQR) age 60.5 (40.5-80.5) vs. 50.5 (30.5-70.5) y), although the age distribution was bimodal, with infants and patients aged > 66 y overrepresented; and were notably more comorbid (73% ASA physical status 3-5 vs. 27% ASA physical status 1-2). The surgical case-mix included more weekend (14% vs. 11%), out-of-hours (19% vs. 10%), non-elective (65% vs. 30%) and major/complex cases (60% vs. 28%). Cardiac arrest was most prevalent in orthopaedic trauma (12%), lower gastrointestinal surgery (10%), cardiac surgery (9%), vascular surgery (8%) and interventional cardiology (6%). Specialities with the highest proportion of cases relative to denominator activity were: cardiac surgery (9% vs. 1%); cardiology (8% vs. 1%); and vascular surgery (8% vs. 2%). The most common causes of cardiac arrest were: major haemorrhage (17%); bradyarrhythmia (9%); and cardiac ischaemia (7%). Patient factors were judged a key cause of cardiac arrest in 82% of cases, anaesthesia in 40% and surgery in 35%.

Peri-operative cardiac arrest: management and outcomes of patients analysed in the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest in the UK, a topic of importance to patients, anaesthetists and surgeons. We report the results of the 12-month registry phase, from 16 June 2021 to 15 June 2022, focusing on management and outcomes. Among 881 cases of peri-operative cardiac arrest, the initial rhythm was non-shockable in 723 (82%) cases, most commonly pulseless electrical activity. There were 665 (75%) patients who survived the initial event and 384 (52%) who survived to hospital discharge. A favourable functional outcome (based on modified Rankin Scale score) was reported for 249 (88%) survivors. Outcomes varied according to arrest rhythm. The highest rates of survival were seen for bradycardic cardiac arrests with 111 (86%) patients surviving the initial event and 77 (60%) patients surviving the hospital episode. The lowest survival rates were seen for patients with pulseless electrical activity, with 312 (68%) surviving the initial episode and 156 (34%) surviving to hospital discharge. Survival to hospital discharge was worse in patients at the extremes of age with 76 (40%) patients aged > 75 y and 9 (45%) neonates surviving. Hospital survival was also associated with surgical priority, with 175 (88%) elective patients and 176 (37%) non-elective patients surviving to discharge. Outcomes varied with the cause of cardiac arrest, with lower initial survival rates for pulmonary embolism (5, 31%) and bone cement implantation syndrome (9, 45%), and hospital survival of < 25% for pulmonary embolism (0), septic shock (13, 24%) and significant hyperkalaemia (1, 20%). Overall care was rated good in 464 (53%) cases, and 18 (2%) cases had overall care rated as poor. Poor care elements were present in a further 245 (28%) cases. Care before cardiac arrest was the phase most frequently rated as poor (92, 11%) with elements of poor care identified in another 186 (21%) cases. These results describe the management and outcomes of peri-operative cardiac arrest in UK practice for the first time.

Organisation of UK hospitals and anaesthetic departments in the treatment of peri-operative cardiac arrest: an analysis from the 7th National Audit Project (NAP7) local co-ordinator baseline survey

We report the results of the Royal College of Anaesthetists' 7th National Audit Project organisational baseline survey sent to every NHS anaesthetic department in the UK to assess preparedness for treating peri-operative cardiac arrest. We received 199 responses from 277 UK anaesthetic departments, representing a 72% response rate. Adult and paediatric anaesthetic care was provided by 188 (95%) and 165 (84%) hospitals, respectively. There was no paediatric intensive care unit on-site in 144 (87%) hospitals caring for children, meaning transfer of critically ill children is required. Remote site anaesthesia is provided in 182 (92%) departments. There was a departmental resuscitation lead in 113 (58%) departments, wellbeing lead in 106 (54%) and departmental staff wellbeing policy in 81 (42%). A defibrillator was present in every operating theatre suite and in all paediatric anaesthesia locations in 193 (99%) and 149 (97%) departments, respectively. Advanced airway equipment was not available in: every theatre suite in 13 (7%) departments; all remote locations in 103 (57%) departments; and all paediatric anaesthesia locations in 23 (15%) departments. Anaesthetic rooms were the default location for induction of anaesthesia in adults and children in 148 (79%) and 121 (79%) departments, respectively. Annual updates in chest compressions and in defibrillation were available in 149 (76%) and 130 (67%) departments, respectively. Following a peri-operative cardiac arrest, debriefing and peer support programmes were available in 154 (79%) and 57 (29%) departments, respectively. While it is likely many UK hospitals are very well prepared to treat anaesthetic emergencies including cardiac arrest, the survey suggests this is not universal.

The 7th National Audit Project (NAP7) baseline survey of individual anaesthetists: preparedness for and experiences of peri-operative cardiac arrest

The Royal College of Anaesthetists' 7th National Audit Project baseline survey assessed knowledge, attitudes, practices and experiences of peri-operative cardiac arrests among UK anaesthetists and Anaesthesia Associates. We received 10,746 responses, representing a 71% response rate. In-date training in adult and paediatric advanced life support was reported by 9646 (90%) and 7125 (66%) anaesthetists, respectively. There were 8994 (84%) respondents who were confident in leading a peri-operative cardiac arrest, with males more confident than females, but only 5985 (56%) were confident in leading a debrief and 7340 (68%) communicating with next of kin. In the previous two years, 4806 (46%) respondents had managed at least one peri-operative cardiac arrest, of which 321 (7%) and 189 (4%) of these events involved a child or an obstetric patient, respectively. Respondents estimated the most common causes of peri-operative cardiac arrest to be hypovolaemia, hypoxaemia and cardiac ischaemia, with haemorrhage coming fifth. However, the most common reported causes for the most recently attended peri-operative cardiac arrest were haemorrhage; (927, 20%); anaphylaxis (474, 10%); and cardiac ischaemia (397, 9%). Operating lists or shifts were paused or stopped after 1330 (39%) cardiac arrests and 1693 (38%) respondents attended a debrief, with 'hot' debriefs most common. Informal wellbeing support was relatively common (2458, 56%) and formal support was uncommon (472, 11%). An impact on future care delivery was reported by 196 (4%) anaesthetists, most commonly a negative psychological impact. Management of a peri-operative cardiac arrest during their career was reported by 8654 (85%) respondents. The overall impact on professional life was more often judged positive (2630, 30%) than negative (1961, 23%), but impact on personal life was more often negative.

Patient characteristics, anaesthetic workload and techniques in the UK: an analysis from the 7th National Audit Project (NAP7) activity survey

Detailed contemporary knowledge of the characteristics of the surgical population, national anaesthetic workload, anaesthetic techniques and behaviours are essential to monitor productivity, inform policy and direct research themes. Every 3-4 years, the Royal College of Anaesthetists, as part of its National Audit Projects (NAP), performs a snapshot activity survey in all UK hospitals delivering anaesthesia, collecting patient-level encounter data from all cases under the care of an anaesthetist. During November 2021, as part of NAP7, anaesthetists recorded details of all cases undertaken over 4 days at their site through an online survey capturing anonymous patient characteristics and anaesthetic details. Of 416 hospital sites invited to participate, 352 (85%) completed the activity survey. From these, 24,177 reports were returned, of which 24,172 (99%) were included in the final dataset. The work patterns by day of the week, time of day and surgical specialty were similar to previous NAP activity surveys. However, in non-obstetric patients, between NAP5 (2013) and NAP7 (2021) activity surveys, the estimated median age of patients increased by 2.3 years from median (IQR) of 50.5 (28.4-69.1) to 52.8 (32.1-69.2) years. The median (IQR) BMI increased from 24.9 (21.5-29.5) to 26.7 (22.3-31.7) kg.m^-2 . The proportion of patients who scored as ASA physical status 1 decreased from 37% in NAP5 to 24% in NAP7. The use of total intravenous anaesthesia increased from 8% of general anaesthesia cases to 26% between NAP5 and NAP7. Some changes may reflect the impact of the COVID-19 pandemic on the anaesthetic population, though patients with confirmed COVID-19 accounted for only 149 (1%) cases. These data show a rising burden of age, obesity and comorbidity in patients requiring anaesthesia care, likely to impact UK peri-operative services significantly.

The Efficacy of 0.75% Bupivacaine with ph Adjustment and Hyaluronidase for Peribulbar Blockade: The Incidence of Prolonged Ptosis

A prospective, double masked, randomised study was performed to compare the speed of onset of peribulbar anaesthesia using pH adjusted 0.75% bupivacaine, with and without the addition of hyaluronidase. No significant difference in speed of onset occurred due to the addition of hyaluronidase. There were 7 cases of post operative ptosis in the study group, including 1 case of orbital apex syndrome and 2 cases of transient 3rd nerve palsy. This incidence of post operative ptosis using pH adjusted 0.75% bupivacaine was statistically significantly greater than in a matched control group who received a 50:50 mixture of 1% lignocaine and 0.5% bupivacaine with hyaluronidase (p < 0.05). The possible causes of this increased incidence of post operative ptosis are discussed.

Intracranial elastance is increased in idiopathic intracranial hypertension

BACKGROUND AND PURPOSE

To date, no pathophysiological model has sufficiently accounted for all the findings encountered in patients with idiopathic intracranial hypertension (IIH). Intracranial elastance is an index of volume-buffering capacity known to play a role in certain disorders of cerebrospinal fluid (CSF) dynamics, which has not been previously investigated in relation to IIH patients.

METHODS

This was a single-center retrospective cohort study from 1 July 2011 to 1 July 2016. Values for opening pressure (P_O ), closing pressure (P_C ) and volume (V) of CSF removed were collected, as well as demographic and clinical covariates. Intracranial elastance (E) and pressure-volume index (PVI) were calculated according to established equations: E = (P_O -P_C )/V and PVI = V/log₁₀ (P_O /P_C ), respectively. Those with an alternative central nervous system pathology, including meningitis, encephalitis and normal pressure hydrocephalus were excluded. Eligible patients were subdivided into two groups based on final diagnosis: a control group and an IIH group.

RESULTS

In our cohort (n = 49), a significant association of both E (P < 0.0001) and PVI (P = 0.005) with a diagnosis of IIH was observed. Median E was 0.45 [interquartile range (IQR) 0.29-0.63] in the control group and 1 (IQR 0.59-1.29) in the IIH group, and median PVI was 98.07 (IQR 59.92-135.86) in the control group and 64.1 (IQR 42.4-91.7) in the IIH group. Neither E nor PVI were significantly associated with age, gender or body mass index. PVI was independent of opening pressure.

CONCLUSIONS

As calculated by clinically accessible indices, our study provides evidence that intracranial elastance is increased in IIH, reflecting a novel insight into disease pathogenesis.

Clinical features and long-term prognosis of trochlear headaches

BACKGROUND AND PURPOSE

Trochlear headaches are a recently recognized cause of headache, of which both primary and inflammatory subtypes are recognized. The clinical features, long-term prognosis and optimal treatment strategy have not been well defined.

METHODS

A cohort of 25 patients with trochlear headache seen at the Mayo Clinic between 10 July 2007 and 28 June 2012 were identified.

RESULTS

The diagnosis of trochlear headache was not recognized by the referring neurologist or ophthalmologist in any case. Patients most often presented with a new daily from onset headache (n = 22, 88%). The most characteristic headache syndrome was reported as continuous, achy, periorbital pain associated with photophobia and aggravation by eye movement, especially reading. Individuals with a prior history of migraine were likely to have associated nausea and experience trochlear migraine. Amongst individuals with trochleitis, 5/12 (41.6%) had an identified secondary mechanism. Treatment responses were generally, but not invariably, favorable to dexamethasone/lidocaine injections near the trochlea. At a median follow-up of 34 months (range 0-68), 10/25 (40%) of the cohort had experienced complete remission.

CONCLUSIONS

Trochlear headaches are poorly recognized, have characteristic clinical features, and often require serial injections to optimize the treatment outcome. The identification of trochleitis should prompt neuroimaging to look for a secondary cause.

Repair of a canine forelimb skin deficit by microvascular transfer of a caudal superficial epigastric flap

Extensive skin loss from the forelimb of a Border collie was repaired by a microvascular caudal superficial epigastric flap, with secondary meshing of the flap to increase coverage. The caudal superficial epigastric artery and vein were anastomosed to the brachial artery and vein. End-to-end anastomosis to the brachial artery and vein did not compromise peripheral blood flow, and no flap necrosis was observed after subsequent limited meshing of the flap.

Infant HIV infection despite "universal" antenatal testing

We reviewed the antenatal HIV testing history, clinical presentation and outcome of 25 infants diagnosed with HIV between 1 January 2001 and 31 December 2005 in a tertiary referral hospital in London. Of the 25 cases, 21 had received antenatal care in the UK. Twelve mothers had not had an antenatal HIV test, four had tested positive antenatally, while five had had a negative HIV test on antenatal booking, implying seroconversion in pregnancy. When mothers had not been diagnosed antenatally, infants presented with severe infections, which were fatal in six cases. The majority (65%) of the children have long-term neurological sequelae. HIV seroconversion is an important cause of infant HIV in the UK.

Cerebral blood flow velocity increases when propofol is changed to desflurane, but not when isoflurane is changed to desflurane in children

BACKGROUND

Children may exhibit delayed emergence following maintenance of anesthesia with propofol or isoflurane. Desflurane is often used towards the end of procedures to facilitate emergence. This study evaluated the effect on middle cerebral artery blood flow velocity (Vmca) in anesthetized children when propofol or isoflurane was substituted with desflurane.

METHODS

Forty-two healthy children aged 1-6 years were enrolled. A standardized anesthetic induction was used. Anesthesia was maintained with remifentanil (0.5 microg.kg(-1) bolus followed by an infusion of 0.2 microg.kg(-1).min(-1)) and a randomly selected sequence of propofol/desflurane/propofol, desflurane/propofol/desflurane, isoflurane/desflurane/isoflurane or desflurane/isoflurane/desflurane. Propofol was administered to maintain a steady-state serum concentration of 3 microg.ml(-1). Desflurane and isoflurane were administered at age-corrected 1 MAC. Hemodynamic stability was maintained. Transcranial Doppler sonography was used to measure Vmca. Hemodynamic variables as well as Vmca were measured 30 min after skin incision and repeated 30 min after each change in anesthetic maintenance agent.

RESULTS

The mean age and weight was 2.3 +/- 1.3 years and 13.0 +/- 3.7 kg, respectively. The Vmca (mean) increased by 35% from 37.7 +/- 10.5 cm s(-1) to 57.8 +/- 14.6 cm s(-1) (P < 0.0001) when propofol was changed to desflurane but was unaffected when desflurane replaced isoflurane.

CONCLUSION

When propofol is changed to desflurane, cerebral blood flow velocity increases significantly in normal children. This cerebral vasodilatory effect may have important implications in the neurosurgical setting.

Predicting outcome in ex-premature infants supported with extracorporeal membrane oxygenation for acute hypoxic respiratory failure

OBJECTIVE

To identify predictors of outcome in ex-premature infants supported with extracorporeal membrane oxygenation (ECMO) for acute hypoxic respiratory failure.

METHODS

Retrospective review of ex-premature infants with acquired acute hypoxic respiratory failure requiring ECMO support in the United Kingdom from 1992 to 2001. Review of follow up questionnaires completed by general practitioners and local paediatricians.

RESULTS

Sixty four ex-premature infants (5-10 each year) received ECMO support, despite increased use of advanced conventional treatments over the decade. The most common infective agent was respiratory syncytial virus (85% of cases). Median birth gestation was 29 weeks and median corrected age at the time of ECMO support was 42 weeks. Median ECMO support duration was relatively long, at 229 hours. Survival to hospital discharge and to 6 months was 80%, remaining similar throughout the period of review. At follow up, 60% had long term neurodisability and 79% had chronic pulmonary problems. Of pre-ECMO factors, baseline oxygen dependence, younger age, and inpatient status were associated with non-survival (p < or = 0.05). Of ECMO related factors, patient complications were independently associated with adverse neurodevelopmental outcome and death (p < 0.01).

CONCLUSIONS

Survival rates for ex-premature infants after ECMO support are favourable, but patients suffer a high burden of morbidity during intensive care and over the long term. At the time of ECMO referral, baseline oxygen dependence is the most important predictor of death, but no combination of the factors considered was associated with a mortality that would preclude ECMO support.

Pre-eclampsia, antiretroviral therapy, and immune reconstitution

Antiretrovirals are standard treatment for HIV-1-positive women during pregnancy in the UK, but little is known about maternal or fetal safety. In our cohort study of 214 pregnant women with HIV-1 infection, those who received no antiretroviral therapy had a rate of pre-eclampsia significantly lower (none of 61) than those on triple antiretroviral therapy (8 of 76; odds ratio 15.3, 95% CI 0.9-270, p=0.0087). However, the rate of pre-eclampsia in HIV-1-positive women on treatment did not differ from that in uninfected controls (12 of 214; p=0.2). The association of HIV-1-related immune deficiency with a low rate of pre-eclampsia, and the restoration of this rate in women treated with triple antiretroviral therapy to the expected rate indicates a pivotal role of the immune system in the pathogenesis of pre-eclampsia. The clinical presentation of pre-eclampsia and toxic effects of antiretroviral therapy could overlap and complicate diagnosis and management in these patients.

Acute rhabdomyolysis after cardiac transplantation: a diagnostic conundrum

A 13-year-old girl presented with right ventricular failure secondary to Ebstein's malformation (downward displacement of the tricuspid valve leaflets with adherence to the right ventricular muscle and redundancy or dysplasia of the tricuspid valve leaflets). She subsequently required a heart transplant but developed rhabdomyolysis early in the postoperative period and required ventilatory support for more than 3 weeks. A variety of causes were considered, but her condition improved only when cyclosporin was eliminated from the immunosuppression regimen. We believe it is likely that the rhabdomyolysis has been caused by cyclosporin. If so, this has occurred both earlier in the clinical course and at lower serum concentrations than previously described.

Comparative effects of phthalate monoesters on gap junctional intercellular communication and peroxisome proliferation in rodent and primate hepatocytes

Several phthalate esters, compounds used as plasticizers in a variety of commercial products, have been shown to induce hepatic tumors in rodents. In this study, the comparative effects of phthalate monoesters on inhibition of gap junctional intercellular communication and induction of peroxisomal beta-oxidation were assessed in primary cultured hepatocytes from rats, mice, hamsters, cynomolgus monkeys, and humans. A human liver cell line was also utilized. Eight monoesters examined included mono-2-ethylhexyl phthalate (MEHP), mono-n-octyl phthalate (MNOP), mono-isononyl phthalate (MINP, 3 types, -1, -2, and -3), mono-isoheptyl phthalate (MIHP), mono-isodecyl phthalate (MIDP), and mono-(heptyl, nonyl, undecyl) phthalate (M711P). Gap junctional intercellular communication was measured 4 and 24 h after treatment by lucifer yellow dye coupling. Gap junctional intercellular communication was inhibited in rat and mouse hepatocytes by all eight monoesters in a concentration-dependent manner. In most cases, gap junctional intercellular communication was significantly reduced at the lowest concentrations tested (50 pM). Inhibition of gap junctional intercellular communication in rodent cells was substantially reversed within 24 h of monoester removal. In contrast, cell-to-cell communication was not inhibited in hamster, cynomolgus, or human hepatocytes or in a human liver cell line at any concentration examined. In rat hepatocytes, peroxisomal beta-oxidation was elevated after treatment with MEHP, MINP, MIHP, and MIDP but not MNOP or M711P, and with all but MIHP in mouse hepatocytes. The eight phthalates produced no marked change on peroxisomal beta-oxidation in hepatocytes from other species. These data provide additional evidence that the toxicological effects of phthalate esters are species specific.

Reversibility and persistence of di-2-ethylhexyl phthalate (DEHP)- and phenobarbital-induced hepatocellular changes in rodents

The tumor promotion stage of chemical carcinogenesis has been shown to exhibit a persistence of cellular effects during treatment and the reversibility of these changes upon cessation of treatment. Inhibition of gap-junctional intercellular communication and increased replicative DNA synthesis appear to be important in this process. The present study assessed the persistence and reversibility of gap-junctional intercellular communication inhibition, peroxisomal proliferation, and replicative DNA synthesis in livers from male F344 rats and B6C3F1 mice. Dietary administration of 20,000 mg/kg DEHP to male rats for 2 weeks decreased intercellular communication (67% of control) and enhanced replicative DNA synthesis (4.8-fold over control). Elevation of the relative liver weight and the induction of peroxisomal beta oxidation were also observed following treatment with 20,000 mg/Kg DEHP for 2 weeks. Following DEHP administration at a dose of 6000 mg/kg for 18 months, inhibition of gap-junctional intercellular communication persisted, and the relative liver weight and induction of peroxisomal beta oxidation remained elevated in both rats and male B6C3F1 mice. Treatment of rats and mice with phenobarbital for 18 months (500-mg/kg diet) also produced an increase in relative liver weight and a decrease in cell-to-cell communication. In recovery studies in which DEHP was administered to male F344 rats for 2 weeks and then withdrawn, the relative liver weight, rate of peroxisomal beta oxidation, increase in replicative DNA synthesis, and inhibition of gap-junctional intercellular communication returned to control values within 2 to 4 weeks after DEHP treatment ceased. Recovery studies with phenobarbital produced similar results. The primary active metabolite of DEHP, mono-2-ethylhexyl phthalate (MEHP), was detected in the livers of animals treated with DEHP for greater than 2 weeks. However, it could not be detected after removal of DEHP from the diet for 2 weeks. This study demonstrated that inhibition of gap-junctional intercellular communication, along with indicators of peroxisomal proliferation, including increased relative liver weight and enhanced peroxisomal beta oxidation, persist while DEHP treatment continues but reverses when treatment is stopped. Studies with phenobarbital produced a similar pattern of response.

Quantitative pathology of inhalational anthrax I: quantitative microscopic findings

Forty-one cases of documented inhalational anthrax from the Sverdlovsk epidemic of 1979 traced to release of aerosols of Bacillus anthracis at a secret biologic-agent production facility were evaluated by semiquantitative histopathologic analysis of tissue concentrations of organisms, inflammation, hemorrhage, and other lesions in the mediastinum, mediastinal lymph nodes, bronchi, lungs, heart, spleen, liver, intestines, kidneys, adrenal glands, and central nervous system. These data were correlated with clinical, epidemiologic, and demographic data. The patients' courses, with a variable incubation period and short nonspecific course (4 days before hospitalization) with rapid demise (1 day of hospitalization before death), correlated with systemic bacterial infection and lesions. Bacillus anthracis were identified in all cases in which there was no antibiotic treatment or there was treatment for fewer than 21 hours. The lesions that were the most severe and apparently of longest duration were in the mediastinal lymph nodes and mediastinum. There and elsewhere, peripheral transudate surrounded fibrin-rich edema; necrosis of arteries and veins was the most likely source of large hemorrhages displacing tissue or infiltrating tissue, respectively; and apoptosis of lymphocytes was observed. Respiratory function was compromised by mediastinal expansion, large pleural effusions, and hematogenous and retrograde lymphatic vessel spread of B. anthracis to the lung with consequent pneumonia. The central nervous system and intestines manifested similar hematogenous spread, vasculitis, hemorrhages, and edema. These pathologic findings are consistent with previous experimental studies showing transport of inhaled spores to mediastinal lymph nodes, where germination and growth lead to local lesions and systemic spread, with resulting edema and cell death, owing to the effects of edema toxin and lethal toxin. The identification of the vascular lesions as a basis for the prominent hemorrhages is a novel observation for human inhalational anthrax.

Obligations to provide appropriate patient management

The Pap test is a successful method of preventing cervical cancer, but it does have significant false negative and false positive rates. The main aim of screening is the detection of precursor lesions, both regression and progression of which may occur, making it difficult to decide upon follow-up and further therapy. Around the world there are many differences, as a far as the frequency of the disease, the organization and economic background of the health care system, the use of different additional diagnostic tools and even the terminology considered. All these factors underline the importance of a consensus on a "minimum level" of obligations to provide appropriate patient management. The screening interval should be two to five years, in some cases even annually. The cytopathologist has an obligation to recommend repeat smears in cases of cytologic abnormalities likely to regress. We recommend the use of standard terminology and stress the importance of a "common language" in cervical cytology. Colposcopy and biopsy are obligatory in cases of HSIL and cancer. We suggest that in severe cases women should be provided with detailed written and verbal information.

Automation and robotics for genetic analysis

This guide to laboratory robotics covers a wide variety of methods amenable to automation including mapping, genotyping, barcoding and data handling, template preparation, reaction setup, colony and plaque picking, and more.

Primary vaginal adenocarcinoma of intestinal type arising from an adenoma: case report and review of the literature

A 1 cm polypoid lesion was encountered on the posterior vaginal wall in a 56-year-old woman with no history of diethylstilbestrol exposure that on microscopic examination was a moderately differentiated adenocarcinoma of intestinal type. The tumor was cytokeratin 20 and carcinoembryonic antigen positive and negative for cytokeratin 7. Mucin histochemistry demonstrated the presence of o-acetylated sialomucin, a specific marker of large intestinal differentiation. The initial interpretation favored a metastasis from a colonic adenocarcinoma, but clinical investigations showed no evidence of a primary gastrointestinal lesion. The morphology, histochemical, and differential cytokeratin profile led to the lesion being reinterpreted as a primary intestinal-type adenocarcinoma of the vagina arising from a tubular adenoma. Although a very rare tumor, awareness of this lesion is important as it must be distinguished from metastatic adenocarcinomas from other sites.

Myeloid cell leukemia 1 is phosphorylated through two distinct pathways, one associated with extracellular signal-regulated kinase activation and the other with G2/M accumulation or protein phosphatase 1/2A inhibition

Protein kinase C activators and microtubule-damaging drugs stimulate BCL2 phosphorylation, which has been associated with either enhancement or inhibition of cell viability. In a Burkitt lymphoma cell line, both types of agents likewise stimulated phosphorylation of myeloid cell leukemia 1 (MCL1), another viability-promoting BCL2 family member. However, while MCL1 phosphorylation induced by the protein kinase C activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), did not affect its electrophoretic mobility, microtubule-damaging agents, such as taxol, induced MCL1 phosphorylation associated with a band shift to decreased mobility. Inhibitors of extracellular signal-regulated kinase (ERK) activation blocked TPA-induced MCL1 phosphorylation but not the taxol-induced band shift. TPA-induced MCL1 phosphorylation occurred rapidly and was not associated with decreased viability, while the taxol-induced band shift occurred upon extended exposure as cells accumulated in G(2)/M followed by cell death. Protein phosphatase 1/2A inhibitors also induced the MCL1 band shift/phosphorylation. Thus, MCL1 undergoes two distinct types of phosphorylation: (i) TPA-induced, ERK-associated phosphorylation, which does not alter the electrophoretic mobility of MCL1, and (ii) ERK-independent phosphorylation, which results in an MCL1 band shift and is induced by events in G(2)/M or protein phosphatase 1/2A inhibitors.

Effects of di-isononyl phthalate, di-2-ethylhexyl phthalate, and clofibrate in cynomolgus monkeys

The effects of the peroxisome proliferators di-isononyl phthalate (DINP) and di-2-ethylhexyl phthalate (DEHP) were evaluated in young adult male cynomolgus monkeys after 14 days of treatment, with emphasis on detecting hepatic and other effects seen in rats and mice after treatment with high doses of phthalates. Groups of 4 monkeys received DINP (500 mg/kg/day), DEHP (500 mg/kg/day), or vehicle (0.5% methyl cellulose, 10 ml/kg) by intragastric intubation for 14 consecutive days. Clofibrate (250 mg/kg/day), a hypolipidemic drug used for cholesterol reduction in human patients was used as a reference substance. None of the test substances had any effect on body weight or liver weights. Histopathological examination of tissues from these animals revealed no distinctive treatment-related effects in the liver, kidney, or testes. There were also no changes in any of the hepatic markers for peroxisomal proliferation, including peroxisomal beta-oxidation (PBOX) or replicative DNA synthesis. Additionally, in situ dye transfer studies using fresh liver slices revealed that DINP, DEHP, and clofibrate had no effect on gap junctional intercellular communication (GJIC). None of the test substances produced any toxicologically important changes in urinalysis, hematology, or clinical chemistry; however, clofibrate produced some emesis, small increases in serum triglyceride, decreased calcium, and decreased weights of testes/epididymides and thyroid/parathyroid. The toxicological significance of these small changes is questionable. The absence of observable hepatic effects in monkeys at doses that produce hepatic effects in rodents suggests that DINP, DEHP, and clofibrate would also not elicit in primates other effects such as liver cancer. These data, along with results from in vitro hepatocyte studies, indicate that rodents are not good animal models for predicting the hepatic effects of phthalates in primates, including humans.

Effects of Di-2-ethylhexyl phthalate (DEHP) on gap-junctional intercellular communication (GJIC), DNA synthesis, and peroxisomal beta oxidation (PBOX) in rat, mouse, and hamster liver

The present study evaluated the effect of di-2-ethylhexyl phthalate (DEHP) on gap-junctional intercellular communication (GJIC), peroxisomal beta-oxidation (PBOX) activity, and replicative DNA synthesis in several rodent species with differing susceptibilities to peroxisome proliferator-induced hepatic tumorigenesis. A low (non-tumorigenic) and high (tumorigenic) dietary concentration of DEHP was administered to male F344 rats for 1, 2, 4, and 6 weeks. Additionally, a previously non-tumorigenic dose (1000 ppm) and tumorigenic dose of DEHP (12,000 ppm), as determined by chronic bioassay data, were examined following 2 weeks dietary administration. Male B6C3F1 mice were fed the non-tumorigenic concentration, 500 ppm, and the tumorigenic concentration, 6000 ppm, of DEHP for two and four weeks. The hepatic effects of low and high concentrations of DEHP, 1000 and 6000 ppm, were also examined in male Syrian Golden hamsters (refractory to peroxisome proliferator-induced tumorigenicity). In rat and mouse liver, a concentration-dependent increase in the relative liver weight, PBOX activity, and replicative DNA synthesis was observed at the earliest time point examined. Concurrent to these observations was an inhibition of GJIC. In hamster liver, a slight increase in the relative liver weight, PBOX activity, and replicative DNA synthesis was observed. However, these effects were not of the same magnitude or consistency as those observed in rats or mice. Furthermore, DEHP had no effect on GJIC in hamster liver at any of the time points examined (2 and 4 weeks). HPLC analysis of DEHP and its primary metabolites, mono-2-ethylhexyl phthalate (MEHP), and phthalate acid (PA), indicated a time- and concentration-dependent increase in the hepatic concentration of MEHP. At equivalent dietary concentrations and time points, the presence of MEHP, the primary metabolite responsible for the hepatic effects of DEHP, demonstrated a species-specific response. The largest increase in the hepatic concentration of MEHP was observed in mice, which was greater than the concentration observed in rats. The hepatic concentration of MEHP was lowest in hamsters. Hepatic concentrations of DEHP and phthalic acid were minimal and did not correlate with concentration and time. Collectively, these data demonstrate the inhibition of hepatic GJIC and increased replicative DNA synthesis correlated with the observed dose- and species-specific tumorigenicity of DEHP and may be predictive indicators of the nongenotoxic carcinogenic potential of phthalate esters.

Comparative in vivo hepatic effects of Di-isononyl phthalate (DINP) and related C7-C11 dialkyl phthalates on gap junctional intercellular communication (GJIC), peroxisomal beta-oxidation (PBOX), and DNA synthesis in rat and mouse liver

The short-term hepatic effects of DINP (CAS 68515-48-0, designated DINP-1) in rats and mice were evaluated at tumorigenic and nontumorigenic doses from previous chronic studies. Groups of male F344 rats were fed diets with DINP-1 at concentrations of 0, 1000, or 12,000 ppm and male B6C3F1 mice at 0, 500, or 6000 ppm DINP-1. After 2 or 4 weeks of treatment, changes in liver weight, gap junctional intercellular communication (GJIC), peroxisomal beta-oxidation (PBOX), and replicative DNA synthesis were examined. In addition, hepatic and serum concentrations of the parent compound and major metabolites were determined. Relative to controls in both species, increased liver weight and PBOX at the high dose of DINP-1 were consistent with peroxisomal proliferation. Hepatic GJIC was inhibited and DNA synthesis was increased at the high dose of DINP-1, which is also consistent with the tumorigenic response in rats and mice reported in other chronic studies at these doses. These hepatic effects were not observed at the low doses of DINP-1. At comparable low doses of DINP-1 in other chronic studies, no liver tumors were observed in rats and mice. The monoester metabolite (MINP-1) was detected in the liver at greater concentrations in mice than rats. This result is also consistent with the dose-response observations in rat and mouse chronic studies. Additionally, other structurally similar dialkyl phthalate esters ranging from C7 to C11 were evaluated using a similar protocol for comparison to DINP-1; these included an alternative isomeric form of DINP (DINP-A), di-isodecyl phthalate (DIDP), di-isoheptyl phthalate (DIHP), di-heptyl, nonyl undecyl phthalate (D711P), and di-n-octyl phthalate (DNOP). Collectively, these data indicate that in rats and mice, DINP-1 and other C7-C11 phthalates exhibit a threshold for inducing hepatic cellular events. Further, where previous chronic data were available for these compounds, these phthalates elicited hepatic effects at doses that correlated with the tumorigenic response. Overall, these studies suggest a good correlation between the inhibition of GJIC when compared with the data on production of liver tumors in chronic studies.

Siblings of retinoblastoma patients: are we underestimating their risk?

PURPOSE

To describe the clinical presentation of probable germ-line mosaicism in four retinoblastoma kindreds.

METHODS

Review of 255 retinoblastoma patients and their family records in a University of California, San Francisco-Bascom Palmer database to identify those with potential germ-line mosaicism. Parents and siblings of retinoblastoma patients were given comprehensive ophthalmologic examinations.

RESULTS

Four kindreds were identified, wherein retinoblastoma was diagnosed in two siblings and both parents demonstrated no evidence of retinoblastoma or retinocytoma.

CONCLUSION

Clinical appearance of germ-line mosaicism is demonstrated in our retinoblastoma patient populations. We recommend routine clinical screening of all parents and siblings of retinoblastoma patients to provide more accurate genetic counseling and to allow earlier examination and treatment of children at presymptomatic disease stages. Germ-line mosaicism must be considered as a genetic transmission pattern in these patients, and genetic counseling should specifically recognize this possibility. If a parent is germ-line mosaic, the possibility of bearing a second child with retinoblastoma is clearly higher than conventionally believed.