Burst-suppression ratio underestimates absolute duration of electroencephalogram suppression compared with visual analysis of intraoperative electroencephalogram

Background

Machine-generated indices based on quantitative electroencephalography (EEG), such as the patient state index (PSI™) and burst-suppression ratio (BSR), are increasingly being used to monitor intraoperative depth of anaesthesia in the endeavour to improve postoperative neurological outcomes, such as postoperative delirium (POD). However, the accuracy of the BSR compared with direct visualization of the EEG trace with regard to the prediction of POD has not been evaluated previously.

Methods

Forty-one consecutive patients undergoing non-cardiac, non-intracranial surgery with general anaesthesia wore a SedLine ® monitor during surgery and were assessed after surgery for the presence of delirium with the Confusion Assessment Method. The intraoperative EEG was scanned for absolute minutes of EEG suppression and correlated with the incidence of POD. The BSR and PSI™ were compared between patients with and without POD.

Results

Visual analysis of the EEG by neurologists and the SedLine ® -generated BSR provided a significantly different distribution of estimated minutes of EEG suppression ( P =0.037). The Sedline ® system markedly underestimated the amount of EEG suppression. The number of minutes of suppression assessed by visual analysis of the EEG was significantly associated with POD ( P =0.039), whereas the minutes based on the BSR generated by SedLine ® were not associated with POD ( P =0.275).

Conclusions

Our findings suggest that SedLine ® (machine)-generated indices might underestimate the minutes of EEG suppression, thereby reducing the sensitivity for detecting patients at risk for POD. Thus, the monitoring of machine-generated BSR and PSI™ might benefit from the addition of a visual tracing of the EEG to achieve a more accurate and real-time guidance of anaesthesia depth monitoring and the ultimate goal, to reduce the risk of POD.

Simulation of MICROBACT Strip Assay Using Colored Liquids to Demonstrate Identification of Unknown Gram-Negative Organisms in Undergraduate Laboratory

Identification of unknown microorganisms to the species level is an important component of a microbiology course. Modern technologies such as matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing offer a rapid species level identification when compared to conventional phenotype-based methods, however they rely on a well-established taxonomy database and phenotypic assays can still play an important role in species determination. Another major limitation is the up-front cost of purchasing these modern specialized instruments and the requirement of skilled personnel to operate specialized equipment and software, which makes them unsuitable to use in the undergraduate teaching laboratory. Commercial biochemical identification systems such as the Oxoid Microbact™ GNB 12A/12E/24E kit is used for the identification of Enterobacteriaceae and other Gram negative bacteria in clinical and veterinary diagnostic laboratories, and food industries for disease control and treatment. In this article, we describe a method of reliably simulating this Microbact™ strip assay using artificial color liquids (which are affordable and easy to source) for the demonstration of phenotypic characterization of unknown Gram negative organisms while providing a safe teaching environment as no bacteria are used, familiarizing students with the concept of using Microbact™ 12A kit to identify a range of unknown Gram negative organisms.

N-methyl-d-aspartate receptor mediated calcium influx supports in vitro differentiation of normal mouse megakaryocytes but proliferation of leukemic cell lines

Background

N-methyl-d-aspartate receptors (NMDARs) contribute calcium influx in megakaryocytic cells but their roles remain unclear; both pro- and anti-differentiating effects have been shown in different contexts.

Objectives

The aim of this study was to clarify NMDAR contribution to megakaryocytic differentiation in both normal and leukemic cells.

Methods

Meg-01, Set-2, and K-562 leukemic cell lines were differentiated using phorbol-12-myristate-13-acetate (PMA, 10 nmol L^-1) or valproic acid (VPA, 500 μmol L^-1). Normal megakaryocytes were grown from mouse marrow-derived hematopoietic progenitors (lineage-negative and CD41a-enriched) in the presence of thrombopoietin (30-40 nmol L^-1). Marrow explants were used to monitor proplatelet formation in the native bone marrow milieu. In all culture systems, NMDARs were inhibited using memantine and MK-801 (100 μmol L^-1); their effects compared against appropriate controls.

Results

The most striking observation from our studies was that NMDAR antagonists markedly inhibited proplatelet formation in all primary cultures employed. Proplatelets were either absent (in the presence of memantine) or short, broad and intertwined (with MK-801). Earlier steps of megakaryocytic differentiation (acquisition of CD41a and nuclear ploidy) were maintained, albeit reduced. In contrast, in leukemic Meg-01 cells, NMDAR antagonists inhibited differentiation in the presence of PMA and VPA but induced differentiation when applied by themselves.

Conclusions

NMDAR-mediated calcium influx is required for normal megakaryocytic differentiation, in particular proplatelet formation. However, in leukemic cells, the main NMDAR role is to inhibit differentiation, suggesting diversion of NMDAR activity to support leukemia growth. Further elucidation of the NMDAR and calcium pathways in megakaryocytic cells may suggest novel ways to modulate abnormal megakaryopoiesis.

Inhibition of glutamate regulated calcium entry into leukemic megakaryoblasts reduces cell proliferation and supports differentiation

Human megakaryocytes release glutamate and express glutamate-gated Ca(2+)-permeable N-methyl-D-aspartate receptors (NMDARs) that support megakaryocytic maturation. While deregulated glutamate pathways impact oncogenicity in some cancers, the role of glutamate and NMDARs in megakaryocytic malignancies remains unknown. The aim of this study was to determine if NMDARs participate in Ca(2+) responses in leukemic megakaryoblasts and if so, whether modulating NMDAR activity could influence cell growth. Three human cell lines, Meg-01, Set-2 and K-562 were used as models of leukemic megakaryoblasts. NMDAR components were examined in leukemic cells and human bone marrow, including in megakaryocytic disease. Well-established NMDAR modulators (agonists and antagonists) were employed to determine NMDAR effects on Ca(2+) flux, cell viability, proliferation and differentiation. Leukemic megakaryoblasts contained combinations of NMDAR subunits that differed from normal bone marrow and the brain. NMDAR agonists facilitated Ca(2+) entry into Meg-01 cells, amplified Ca(2+) responses to adenosine diphosphate (ADP) and promoted growth of Meg-01, Set-2 and K-562 cells. Low concentrations of NMDAR inhibitors (riluzole, memantine, MK-801 and AP5; 5-100μM) were weakly cytotoxic but mainly reduced cell numbers by suppressing proliferation. The use-dependent NMDAR inhibitor, memantine (100μM), reduced numbers and proliferation of Meg-01 cells to less than 20% of controls (IC50 20μM and 36μM, respectively). In the presence of NMDAR inhibitors cells acquired morphologic and immunophenotypic features of megakaryocytic differentiation. In conclusion, NMDARs provide a novel pathway for Ca(2+) entry into leukemic megakaryoblasts that supports cell proliferation but not differentiation. NMDAR inhibitors counteract these effects, suggesting a novel opportunity to modulate growth of leukemic megakaryoblasts.

Congenital dermoid inclusion cyst over the anterior fontanelle: report of two cases

Congenital dermoid inclusion cyst over the anterior fontanelle (CDIC) is an uncommon cystic lesion. It is a benign and curative lesion. In these two cases a soft, cystic mass located over the anterior fontanelle. The cyst had no intracranial extension and was easily excised intact. The clinical and image findings of the cysts were described and compared with the usual dermoids. Many different types of lesions over the children's skull exist and some are commonly diagnosed in daily practice. Congenital dermoid inclusion cyst over the anterior fontanelle (CDIC) is a rare and benign lesion.Pulse Vol.7 January-December 2014 p.42-45

A case report on interhemispheric epidermoid tumor

A 30 year old man admitted with the complaints of generalized convulsions, headache and amnesia. The radiological and neuro-pathological findings were interhemispheric epidermoid tumor, which is a rare location. The tumor was removed completely. The diagnosis and management of epidermoid tumors are discussed by reviewing the literature.Pulse Vol.7 January-December 2014 p.46-49

Retrospective comparison of decompressive hemicraniectomy and hematoma evacuation for spontaneous supratentorial intracerebral hematoma

Objectives: The aim of this study was to test the hypothesis that decompressive hemicraniectomy (DHC), compared with craniotomy with evacuation of hematoma, and would improve clinical outcomes of patients with supratentorial intracerebral hemorrhage (SICH).Methods: We compared patients (November 2008–February 2014) with supratentorial ICH treated with DHC without hematoma evacuation and craniotomy with hematoma evacuation. DHC measured at least 150 mm and included opening of the dura. We analyzed clinical, radiological, and surgical characteristics. Outcome at 6 months was divided into good (modified Rankin Scale 0–4) and poor (modified Rankin Scale 5–6).Results: Fifteen patients (mean age 58 years) with ICH were treated by DHC. Median hematoma volume was 61 ml and mean preoperative Glasgow Coma Scale (GCS) was 7. Ten patients had good and five had poor outcomes. In hematoma evacuation group 29 patients were treated. Median hematoma volume was 55 ml and mean preoperative Glasgow Coma Scale (GCS) was 8. Seventeen patients had good and twelve had poor outcomes.Conclusions: DHC is more effective than hematoma evacuation in patients with SICH. Based on this small cohort, DHC may reduce mortality. Larger prospective study is warranted to assess safety and efficacy.Pulse Vol.7 January-December 2014 p.16-21

Should anastomotic assessment with flexible sigmoidoscopy be routine following laparoscopic restorative left colorectal resection?

AIM

The aim of the study was to evaluate the value of routine intra-operative flexible sigmoidoscopy (IOFS) for left-sided anastomotic integrity and to determine the safest step after a positive leak test.

METHOD

All consecutive patients undergoing left-sided colorectal resections for benign and malignant disease between August 2005 and April 2011 were included. Data regarding procedure, type of anastomosis and outcomes of IOFS were collected. A positive intra-operative leak test resulted in redoing the anastomosis and repeating the leak test.

RESULTS

A total of 415 consecutive patients underwent hand-assisted laparoscopic colorectal resection with a colorectal/ileoanal anastomosis. All patients underwent IOFS. Seventeen patients had abnormality on IOFS. Fifteen patients had a positive air leak test. One patient had anastomotic bleeding. There was one stapler misfiring. Fourteen anastomoses were redone without diversion. One patient required diversion to protect the ileoanal anastomosis and another had already been diverted. Minor bleeding from the staple line in one patient resolved without intervention; however, he had a postoperative anastomotic leak needing surgical intervention. None of the patients who had a takedown and refashioning of the anastomosis following a positive leak on IOFS had postoperative anastomotic leakage or bleeding. Our overall anastomotic leak rate was 2.1%.

CONCLUSIONS

Intra-operative flexible sigmoidoscopy for restorative colorectal resection is safe and reliable and should be performed routinely to assess anastomotic integrity and bleeding. Refashioning the anastomosis after formal takedown would obviate the risk of leakage and is our recommended method of managing intra-operative leaks.

The role of a multidisciplinary pre-assessment clinic in reducing mortality after complex orthopaedic surgery

INTRODUCTION

This paper describes an audit loop. The aim of this study was to audit the effect of a specialised preoperative anaesthetic assessment clinic after hip and knee arthroplasty and revision arthroplasty.

PATIENTS AND METHODS

We studied patients undergoing hip and knee surgery (arthroplasty and revision arthroplasty). We collected data concerning postoperative admissions to the high dependency unit (HDU), intensive care unit (ICU) and post-anaesthesia care unit (PACU) (planned and unplanned rates of admission, length of stay). We also noted mortality. In the first part of the study (April 2005 to March 2006) we studied 298 patients. All patients were assessed independently by an anaesthetist on the day of surgery. A multidisciplinary preoperative assessment clinic commenced in April 2006. After this date all patients were assessed preoperatively by a multidisciplinary anaesthetic lead team. In the second part of the study (May 2006 to April 2009) a further 1,147 arthroplasty patients were studied. Data were again collected regarding HDU, ICU, PACU and mortality, as noted above.

RESULTS

We found statistically significant (p = 0.001) reductions in the admissions to PACU (22% down to 10%) and in mortality (6.1% down to 1.2%) after the introduction of the pre-assessment clinic. There was also a statistically significant (p = 0.01) reduction in the HDU length of stay (2.1 days to 1.6 days), ICU unplanned admissions (1.3% to 0.4%) and the ICU length of stay (2.3 to 1.9 days). We estimated cost savings of nearly £50,000 in the second part of the study. This is based on the average decrease in HDU and ICU length of stay.

CONCLUSIONS

We recommend the use of a multidisciplinary pre-assessment clinic for complex orthopaedic surgery.

The role of recombinant activated Factor VII in major obstetric haemorrhage: the Farnborough experience

Major obstetric haemorrhage is one of the commonest causes of maternal mortality and morbidity worldwide. It may result in coagulopathy and diffuse pelvic or vaginal bleeding. Correction of coagulopathy when administering Factor VII may be crucial to the management of selected cases. We report the use of recombinant activated factor in three cases of massive obstetric haemorrhage. Prolonged international normalised ratio, activated partial thromboplastin time, and reduced fibrinogen were the trigger to use rFVIIa. It was effective to halt the process of coagulopathy, secure haemostasis and improve laboratory parameters in all three patients. We review the relevant literature and discuss its indications, the potential benefits and possible complications. Recombinant activated Factor VII is a potential haemostatic agent in massive obstetric haemorrhage. Its successful use has been reported in post-surgical bleeding and consumptive coagulopathy. It may abolish the need for hysterectomy, which has a devastating effect on the patient future fertility and psychological well-being.

Maternal nutritional history predicts obesity in adult offspring independent of postnatal diet

Significant alterations in maternal nutrition may induce long-term metabolic consequences in offspring, in particular obesity and leptin and insulin resistance. Although maternal nutrient deprivation has been well characterized in this context, there is a relative paucity of data on how high fat (HF) nutrition impacts on the subsequent generation. The present study investigated the effects of maternal HF nutrition either throughout the mother's life up to and including pregnancy and lactation or HF nutrition restricted to pregnancy and lactation, on growth and metabolic parameters in male and female offspring. Virgin Wistar rats were assigned to one of three experimental groups: (1) controls (Cont): dams fed a standard chow diet throughout their life and throughout pregnancy and lactation; (2) maternal high fat (MHF) group: dams fed a HF diet from weaning up to and throughout pregnancy and lactation; and (3) pregnancy and lactation high fat (PLHF): dams fed a chow diet through their life until conception and then fed a HF diet throughout pregnancy and lactation. At weaning, all offspring were fed either a chow or HF diet for the remainder of the study (160 days). Litter size and sex ratios were not significantly different between the groups. MHF and PLHF offspring had significantly lower body weights and were hypoleptinaemic and hypoinsulinaemic at birth compared to Cont offspring. As adults however, chow-fed MHF and PLHF offspring were significantly more obese than Cont offspring (DEXA scanning at day 150, P < 0.001 for maternal HF diet). As expected a postweaning HF diet resulted in increased adiposity in all groups; MHF and PLHF offspring, however, always remained significantly more obese than Cont offspring. Increased adiposity in MHF and PLHF offspring was paralleled by hyperinsulinaemia and hyperleptinaemia (P < 0.001; MHF and PLHF versus Cont). It is of interest that a lifetime of HF nutrition produced a similar offspring phenotype to HF nutrition restricted to pregnancy and lactation alone, thus suggesting that the postnatal sequelae of maternal HF nutrition occurs independent of preconceptional diet. These data further reinforce the importance of maternal nutrition during these critical windows of development and show that maternal HF feeding can induce a markedly obese phenotype in male and female offspring completely independent of postnatal nutrition.

Effects of spermatozoa during in vitro meiosis progression in the porcine germinal vesicle oocytes

We have investigated the effect of co-culture with porcine spermatozoa on in vitro maturation of porcine germinal vesicle (GV) oocytes before fertilization. Most oocytes were arrested at the first prophase of meiosis when oocytes were cultured in TCM 199 alone, but the proportion of oocytes that reached metaphase II was significantly elevated by co-incubation with spermatozoa in vitro. The oocyte maturation effect was observed with intact and parts of spermatozoa (head and tail) collected from adult swine (regardless of source). However, gonocytes from the newborn porcine testis were not able to enhance in vitro maturation of porcine germinal vesicle oocytes. Interestingly, the oocyte maturation effect by spermatozoa was not decreased with heat treatment, but the maturation effect of oocyte treatment disappeared with exposure to detergent in sperm suspension. Porcine spermatozoa were also observed to stimulate meiosis of oocytes, which was maintained at meiotic arrest using dibutyryl cyclic AMP or forskolin. The study suggests that (i) membrane of porcine spermatozoa contains a substance(s) that can enhance in vitro maturation of oocytes prior to fertilization, (ii) the putative meiosis-enhancing substance(s) of spermatozoa from adult testes retains the oocyte maturation effect during transportation of spermatozoa through epididymis, and (iii) the putative meiosis-enhancing substance(s) is able to overcome the inhibitory effect of dibutyryl cyclic AMP or forskolin by inducing germinal vesicle breakdown of porcine cumulus-oocyte complexes maintained in meiotic arrest.

Improved detection of medullary thyroid cancer with radiolabeled antibodies to carcinoembryonic antigen

PURPOSE

This investigation was undertaken to assess the targeting of established and occult medullary thyroid cancer (MTC) with radiolabeled monoclonal antibodies (MAbs) reactive with carcinoembryonic antigen (CEA).

PATIENTS AND METHODS

Twenty-six assessable patients with known (n = 17) or occult (n = 9) MTC were studied with radiolabeled anti-CEA MAbs. Scintigraphic images were collected to determine targeting of tumor lesions.

RESULTS

The targeting results of technetium 99m (99mTc)-,iodine 123 (123I)-, and iodine 131 (131I)-labeled anti-CEA antibodies (all directed against the same epitope of CEA) indicated that all these reagents were capable of detecting established and occult MTC. The sensitivity for detection of known sites of disease ranged from 76% to 100% for the various anti-CEA MAbs used, when compared with computed tomography (CT), magnetic resonance imaging (MRI), bone scan, or other imaging modalities. Moreover, the antibody scan was positive in seven of nine patients with occult disease (patients with negative conventional imaging studies, but who had elevated calcitonin and/or CEA levels). Three of seven patients underwent surgery and the disease was confirmed by histopathology in all three.

CONCLUSION

Anti-CEA MAbs are excellent agents for imaging recurrent, residual, or metastatic MTC. The high lesion sensitivity in patients with known lesions, combined with the ability to detect disease, may make these agents ideal for staging patients, monitoring disease pretherapy or posttherapy, and especially for evaluating patients with recurrent or persistent hypercalcitonemia or CEA elevations after primary surgery. Analogous to radioiodine in the evaluation of patients with differentiated thyroid cancer, radiolabeled anti-CEA MAbs may achieve a similar role in diagnosing and monitoring patients with MTC.