Early risk factors for prolonged mechanical ventilation in patients with severe blunt thoracic trauma: A retrospective cohort study

BACKGROUND

A significant proportion of patients with severe chest trauma require mechanical ventilation (MV). Early prediction of the duration of MV may influence clinical decisions. We aimed to determine early risk factors for prolonged MV among adults suffering from severe blunt thoracic trauma.

METHODS

This retrospective, single-center, cohort study included all patients admitted between January 2014 and December 2020 due to severe blunt chest trauma. The primary outcome was prolonged MV, defined as invasive MV lasting more than 14 days. Multivariable logistic regression was performed to identify independent risk factors for prolonged MV.

RESULTS

The final analysis included 378 patients. The median duration of MV was 9.7 (IQR 3.0-18.0) days. 221 (58.5 %) patients required MV for more than 7 days and 143 (37.8 %) for more than 14 days. Male gender (aOR 3.01, 95 % CI 1.63-5.58, p < 0.001), age (aOR 1.40, 95 % CI 1.21-1.63, p < 0.001, for each category above 30 years), presence of severe head trauma (aOR 3.77, 95 % CI 2.23-6.38, p < 0.001), and transfusion of >5 blood units on admission (aOR 2.85, 95 % CI 1.62-5.02, p < 0.001) were independently associated with prolonged MV. The number of fractured ribs and the extent of lung contusions were associated with MV for more than 7 days, but not for 14 days. In the subgroup of 134 patients without concomitant head trauma, age (aOR 1.63, 95 % CI 1.18-2.27, p = 0.004, for each category above 30 years), respiratory comorbidities (aOR 9.70, 95 % CI 1.49-63.01, p = 0.017), worse p/f ratio during the first 24 h (aOR 1.55, 95 % CI 1.15-2.09, p = 0.004), and transfusion of >5 blood units on admission (aOR 5.71 95 % CI 1.84-17.68, p = 0.003) were independently associated with MV for more than 14 days.

CONCLUSIONS

Several predictors have been identified as independently associated with prolonged MV. Patients who meet these criteria are at high risk for prolonged MV and should be considered for interventions that could potentially shorten MV duration and reduce associated complications. Hemodynamically stable, healthy young patients suffering from severe thoracic trauma but no head injury, including those with extensive lung contusions and rib fractures, have a low risk of prolonged MV.

Association Between Admission Ionized Calcium Level and Neurological Outcome of Patients with Isolated Severe Traumatic Brain Injury: A Retrospective Cohort Study

BACKGROUND

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Pathophysiological processes following initial insult are complex and not fully understood. Ionized calcium (Ca++) is an essential cofactor in the coagulation cascade and platelet aggregation, and hypocalcemia may contribute to the progression of intracranial bleeding. On the other hand, Ca++ is an important mediator of cell damage after TBI and cellular hypocalcemia may have a neuroprotective effect after brain injury. We hypothesized that early hypocalcemia might have an adverse effect on the neurological outcome of patients suffering from isolated severe TBI. In this study, we aimed to evaluate the relationship between admission Ca++ level and the neurological outcome of these patients.

METHODS

This was a retrospective, single-center, cohort study of all patients admitted between January 2014 and December 2020 due to isolated severe TBI, which was defined as head abbreviated injury score ≥ 4 and an absence of severe (abbreviated injury score > 2) extracranial injuries. The primary outcome was a favorable neurological status at discharge, defined by a modified Rankin Scale of 0-2. Multivariable logistic regression was performed to determine whether admission hypocalcemia (Ca++  < 1.16 mmol L-1) is an independent predictor of neurological status at discharge.

RESULTS

The final analysis included 201 patients. Hypocalcemia was common among patients with isolated severe TBI (73.1%). Most of the patients had mild hypocalcemia (1 < Ca++  < 1.16 mmol L-1), and only 13 (6.5%) patients had Ca++  ≤ 1.00 mmol L-1. In the entire cohort, hypocalcemia was independently associated with higher rates of good neurological status at discharge (adjusted odds ratio of 3.03, 95% confidence interval 1.11-8.33, p = 0.03). In the subgroup of 81 patients with an admission Glasgow Coma Scale > 8, 52 (64.2%) had hypocalcemia. Good neurological status at discharge was recorded in 28 (53.8%) of hypocalcemic patients compared with 14 (17.2%) of those with normal Ca++ (p = 0.002). In multivariate analyses, hypocalcemia was independently associated with good neurological status at discharge (adjusted odds ratio of 6.67, 95% confidence interval 1.39-33.33, p = 0.02).

CONCLUSIONS

Our study demonstrates that among patients with isolated severe TBI, mild admission hypocalcemia is associated with better neurological status at hospital discharge. The prognostic value of Ca++ may be greater among patients with admission Glasgow Coma Scale > 8. Trials are needed to investigate the role of hypocalcemia in brain injury.

Automating medical simulations

OBJECTIVE

This study aims to explore speech as an alternative modality for human activity recognition (HAR) in medical settings. While current HAR technologies rely on video and sensory modalities, they are often unsuitable for the medical environment due to interference from medical personnel, privacy concerns, and environmental limitations. Therefore, we propose an end-to-end, fully automatic objective checklist validation framework that utilizes medical personnel's uttered speech to recognize and document the executed actions in a checklist format.

METHODS

Our framework records, processes, and analyzes medical personnel's speech to extract valuable information about performed actions. This information is then used to fill the corresponding rubrics in the checklist automatically.

RESULTS

Our approach to activity recognition outperformed the online expert examiner, achieving an F1 score of 0.869 on verbal tasks and an ICC score of 0.822 with an offline examiner. Furthermore, the framework successfully identified communication failures and medical errors made by physicians and nurses.

CONCLUSION

Implementing a speech-based framework in medical settings, such as the emergency room and operation room, holds promise for improving care delivery and enabling the development of automated assistive technologies in various medical domains. By leveraging speech as a modality for HAR, we can overcome the limitations of existing technologies and enhance workflow efficiency and patient safety.

Outcomes of basic versus advanced prehospital life support in severe pediatric trauma

OBJECTIVE

The role of basic life support (BLS) vs. advanced life support (ALS) in pediatric trauma is controversial. Although ALS is widely accepted as the gold standard, previous studies have found no advantage of ALS over BLS care in adult trauma. The objective of this study was to evaluate whether ALS transport confers a survival advantage over BLS among severely injured children.

METHODS

A retrospective cohort study of data included in the Israeli National Trauma Registry from January 1, 2011, through December 31, 2020 was conducted. All the severely injured children (age < 18 years and injury severity score [ISS] ≥16) were included. Patient survival by mode of transport was analyzed using logistic regression.

RESULTS

Of 3167 patients included in the study, 65.1% were transported by ALS and 34.9% by BLS. Significantly more patients transported by ALS had ISS ≥25 as well as abnormal vital signs at admission. The ALS and BLS cohorts were comparable in age, gender, mechanism of injury, and prehospital time. Children transported by ALS had higher in-hospital mortality (9.2% vs. 0.9%, p < 0.001). Following risk adjustment, patients transported by ALS teams were significantly more likely to die than patients transported by BLS (adjusted OR 2.27, 95% CI 1.05-5.41, p = 0.04). Patients with ISS ≥50 had comparable mortality rates in both groups (45.9% vs. 55.6%, p = 0.837) while patients with GCS <9 transported by ALS had higher mortality (25.9% vs. 11.5%, p = 0.019). Admission to a level II trauma center vs. a level I hospital was also associated with increased mortality (adjusted OR 2.78 (95% CI 1.75-4.55, p < 0.001).

CONCLUSIONS

Among severely injured children, prehospital ALS care was not associated with lower mortality rates relative to BLS care. Because of potential confounding by severity in this retrospective analysis, further studies are warranted to validate these results.

Connected consciousness after tracheal intubation in young adults: an international multicentre cohort study

BACKGROUND

Connected consciousness, assessed by response to command, occurs in at least 5% of general anaesthetic procedures and perhaps more often in young people. Our primary objective was to establish the incidence of connected consciousness after tracheal intubation in young people aged 18-40 yr. The secondary objectives were to assess the nature of these responses, identify relevant risk factors, and determine their relationship to postoperative outcomes.

METHODS

This was an international, multicentre prospective cohort study using the isolated forearm technique to assess connected consciousness shortly after tracheal intubation.

RESULTS

Of 344 enrolled subjects, 338 completed the study (mean age, 30 [standard deviation, 6.3] yr; 232 [69%] female). Responses after intubation occurred in 37/338 subjects (11%). Females (13%, 31/232) responded more often than males (6%, 6/106). In logistic regression, the risk of responsiveness was increased with female sex (odds ratio [ORadjusted]=2.7; 95% confidence interval [CI], 1.1-7.6; P=0.022) and was decreased with continuous anaesthesia before laryngoscopy (ORadjusted=0.43; 95% CI, 0.20-0.96; P=0.041). Responses were more likely to occur after a command to respond (and not to nonsense, 13 subjects) than after a nonsense statement (and not to command, four subjects, P=0.049).

CONCLUSIONS

Connected consciousness occured after intubation in 11% of young adults, with females at increased risk. Continuous exposure to anaesthesia between induction of anaesthesia and tracheal intubation should be considered to reduce the incidence of connected consciousness. Further research is required to understand sex-related differences in the risk of connected consciousness.

Spatiotemporal patterns of population response in the visual cortex under isoflurane: from wakefulness to loss of consciousness

Anesthetic drugs are widely used in medicine and research to mediate loss of consciousness (LOC). Isoflurane is a commonly used anesthetic drug; however, its effects on cortical sensory processing, in particular around LOC, are not well understood. Using voltage-sensitive dye imaging, we measured visually evoked neuronal population response from the visual cortex in awake and anesthetized mice at 3 increasing concentrations of isoflurane, thus controlling the level of anesthesia from wakefulness to deep anesthesia. At low concentration of isoflurane, the effects on neuronal measures were minor relative to the awake condition. These effects augmented with increasing isoflurane concentration, while around LOC point, they showed abrupt and nonlinear changes. At the network level, we found that isoflurane decreased the stimulus-evoked intra-areal spatial spread of local neural activation, previously reported to be mediated by horizontal connections, and also reduced intra-areal synchronization of neuronal population. The synchronization between different visual areas decreased with higher isoflurane levels. Isoflurane reduced the population response amplitude and prolonged their latencies while higher visual areas showed increased vulnerability to isoflurane concentration. Our results uncover the changes in neural activity and synchronization at isoflurane concentrations leading to LOC and suggest reverse hierarchical shutdown of cortical areas.

Dexmedetomidine depresses neuronal activity in the subthalamic nucleus during deep brain stimulation electrode implantation surgery

Background

Micro-electrode recordings are often necessary during electrode implantation for deep brain stimulation of the subthalamic nucleus. Dexmedetomidine may be a useful sedative for these procedures, but there is limited information regarding its effect on neural activity in the subthalamic nucleus and on micro-electrode recording quality.

Methods

We recorded neural activity in five patients undergoing deep brain stimulation implantation to the subthalamic nucleus. Activity was recorded after subthalamic nucleus identification while patients received dexmedetomidine sedation (loading - 1 μg kg-1 over 10-15 min, maintenance - 0.7 μg kg-1 h-1). We compared the root-mean square (RMS) and beta band (13-30 Hz) oscillation power of multi-unit activity recorded by microelectrode before, during and after recovery from dexmedetomidine sedation. RMS was normalised to values recorded in the white matter.

Results

Multi-unit activity decreased during sedation in all five patients. Mean normalised RMS decreased from 2.8 (1.5) to 1.6 (1.1) during sedation (43% drop, p = 0.056). Beta band power dropped by 48.4%, but this was not significant (p = 0.15). Normalised RMS values failed to return to baseline levels during the time allocated for the study (30 min).

Conclusions

In this small sample, we demonstrate that dexmedetomidine decreases neuronal firing in the subthalamic nucleus as expressed in the RMS of the multi-unit activity. As multi-unit activity is a factor in determining the subthalamic nucleus borders during micro-electrode recordings, dexmedetomidine should be used with caution for sedation during these procedures.

Clinical trial number

NCT01721460.

Thalamic deep brain stimulation paradigm to reduce consciousness: Cortico-striatal dynamics implicated in mechanisms of consciousness

Anesthetic manipulations provide much-needed causal evidence for neural correlates of consciousness, but non-specific drug effects complicate their interpretation. Evidence suggests that thalamic deep brain stimulation (DBS) can either increase or decrease consciousness, depending on the stimulation target and parameters. The putative role of the central lateral thalamus (CL) in consciousness makes it an ideal DBS target to manipulate circuit-level mechanisms in cortico-striato-thalamic (CST) systems, thereby influencing consciousness and related processes. We used multi-microelectrode DBS targeted to CL in macaques while recording from frontal, parietal, and striatal regions. DBS induced episodes of abnormally long, vacant staring with low-frequency oscillations here termed vacant, perturbed consciousness (VPC). DBS modulated VPC likelihood in a frequency-specific manner. VPC events corresponded to decreases in measures of neural complexity (entropy) and integration (Φ*), proposed indices of consciousness, and substantial changes to communication in CST circuits. During VPC, power spectral density and coherence at low frequencies increased across CST circuits, especially in thalamo-parietal and cortico-striatal pathways. Decreased consciousness and neural integration corresponded to shifts in cortico-striatal network configurations that dissociated parietal and subcortical structures. Overall, the features of VPC and implicated networks were similar to those of absence epilepsy. As this same multi-microelectrode DBS method–but at different stimulation frequencies–can also increase consciousness in anesthetized macaques, it can be used to flexibly address questions of consciousness with limited confounds, as well as inform clinical investigations of other consciousness disorders.

Deep brain stimulation (DBS) is an effective treatment for a number of neurological and psychiatric disorders. Recent evidence shows that thalamic DBS can increase consciousness under general anesthesia, and has the potential to be an effective treatment for disorders of consciousness like coma. However, past studies also imply that thalamic DBS can decrease consciousness by producing periods of inactivity with vacant staring. In this study, we use thalamic DBS to induce vacant periods of perturbed consciousness (VPC) while recording from frontal, parietal and subcortical brain areas. Much of modern research on consciousness focuses on cortical contributions, debating if frontal or more posterior areas are more important. We show via machine learning, information theoretic and functional connectivity measures that VPC involves altered neural communication between parietal cortex and subcortical regions, challenging a cortico-centric focus. Further, these mechanisms resemble those associated with absence epilepsy, suggesting a link between this disorder of consciousness and VPC. Finally, occurrence of VPC in our study was stimulation frequency-dependent and influenced by the experimental history of DBS. This provides insight to mechanisms of thalamic DBS, informative for clinical manipulations of consciousness.

Admission hypocalcemia in pediatric major trauma patients-An uncommon phenomenon associated with an increased need for urgent blood transfusion

BACKGROUND

Hemorrhage is a leading cause of death among children. Recent data from adult trauma suggests that early, transfusion-unrelated, hypocalcemia is common and that it is associated with an increased need for blood transfusion, mortality, and coagulopathy. The objectives of this study are to evaluate the prevalence of admission hypocalcemia in severely injured children and its correlation with urgent blood transfusion.

STUDY DESIGN AND METHODS

This is a retrospective cohort study of all severely injured (Injury Severity Score [ISS] > 15) pediatric (<18 years) trauma patients admitted to Rambam Health Care Campus, Israel between 2012 and 2020. We excluded patients transferred from other facilities and those who received blood before determining calcium levels. Severe hypocalcemia was defined as ionized calcium (Ca⁺⁺ ) < 1.0 mmol/L and mild hypocalcemia as 1.0 mmol/L ≤ Ca⁺⁺  < 1.1 mmol/L. The primary outcome was urgent blood transfusion (transfusion in the emergency department [ED]).

RESULTS

Six hundred seventy-three severely injured children were admitted from the field. Ca⁺⁺ levels were determined before blood transfusion in 457 patients. Severe hypocalcemia was found in three patients (0.7%) and mild hypocalcemia in additional 21 patients (4.6%). Hypocalcemic patients required more urgent blood transfusion (29.2% vs. 6.5%, p < .001) and had higher ISS (29 [interquartile range, IQR: 22-35] vs. 25 [IQR: 19-34], p = .05). Multivariable logistic regression analysis identified Ca⁺⁺  < 1.1 mmol/L as an independent predictor of the need for blood transfusion, odds ratio 5.44 (95% confidence interval 1.44-20.58), p = .01.

DISCUSSION

Contrary to adults, admission hypocalcemia is uncommon in severely injured children. However, it may be associated with an increased risk of blood transfusion in the ED.

Prevalence of significant traumatic brain injury among patients intubated in the field due to impaired level of consciousness

OBJECTIVE

Current guidelines advocate prehospital endotracheal intubation (ETI) in patients with suspected severe head injury and impaired level of consciousness. However, the ability to identify patients with traumatic brain injury (TBI) in the prehospital setting is limited and prehospital ETI carries a high complication rate. We investigated the prevalence of significant TBI among patients intubated in the field for that reason.

METHODS

Data were retrospectively collected from emergency medical services and hospital records of trauma patients for whom prehospital ETI was attempted and who were transferred to Rambam Health Care Campus, Israel. The indication for ETI was extracted. The primary outcome was significant TBI (clinical or radiographic) among patients intubated due to suspected severe head trauma.

RESULTS

In 57.3% (379/662) of the trauma patients, ETI was attempted due to impaired consciousness. 349 patients were included in the final analysis: 82.8% were male, the median age was 34 years (IQR 23.0-57.3), and 95.7% suffered blunt trauma. 253 patients (72.5%) had significant TBI. In a multivariable analysis, Glasgow Coma Scale>8 and alcohol intoxication were associated with a lower risk of TBI with OR of 0.26 (95% CI 0.13-0.51, p < 0.001) and 0.16 (95% CI 0.06-0.46, p < 0.001), respectively.

CONCLUSION

Altered mental status in the setting of trauma is a major reason for prehospital ETI. Although most of these patients had TBI, one in four of them did not suffer a significant TBI. Patients with a higher field GCS and those suffering from intoxication have a higher risk of misdiagnosis. Future studies should explore better tools for prehospital assessment of TBI and ways to better define and characterize patients who may benefit from early ETI.

Differences in the thermal properties and surface temperature of prehospital antihypothermia devices: an in vitro study

BACKGROUND

Preventing and treating hypothermia in prehospital settings is crucial. Several products have been developed to prevent heat loss and actively warm patients in prehospital settings. We compared the efficacy and the surface temperature of different antihypothermia products, using a fluid-based model at two ambient temperatures.

METHODS

We tested five active (Blizzard Heat with active pads, Ready-Heat, Ready-Heat-II, Hypothermia Prevention and Management Kit (HPMK), Bair Hugger) and five passive (Blizzard Heat, Heat Reflective Shell, sleeping bag, 'space blanket', wool blanket) antihypothermia products. A torso model consisting of four 8 L bags of fluid preheated to 36°C±0.5°C (97±0.5°F) was used to compare the devices' performances at 20°C (68°F) and 8°C (46°F). Inner and surface temperatures were recorded for up to 480 min.

RESULTS

We found significant differences in heat loss in fluid bags among the tested devices at both temperatures (p<0.001). At 20°C, only HPMK and Ready-Heat-II increased the inner temperature for 480 min while Blizzard Heat with active pads prevented heat loss. Ready-Heat prevented heat loss for 90 min. All the other devices did not prevent heat loss beyond 30 min. At 8°C, none of the products heated the model. Bair Hugger, HPMK, Ready-Heat II and sleeping bag prevented heat loss for 30 min. At 60, 90 and 120 min HPMK, Ready-Heat II and Bair Hugger were the most effective. Over 480 min, Bair Hugger was most effective, with a heat loss of 2.3°C±0.4°C. The surface temperature exceeded 44°C (111°F) for all the exothermic warming devices when used for a prolonged period of time.

CONCLUSION

At 20°C, HPMK and Ready-Heat-II increased fluid temperature in the model, while the other devices decreased heat loss. At 8°C, none of the tested devices increased the temperature. However, active heating devices prevented heat loss slightly better than passive methods. A protective insulation layer should be used with all active heating blankets.

Hypocalcemia is associated with adverse clinical course in patients with upper gastrointestinal bleeding

Acute non-variceal upper gastrointestinal bleeding (NV-UGIB) is associated with significant morbidity and mortality. Early and efficient risk stratification can facilitate management and improve outcomes. We aimed to determine whether the level of ionized calcium (Ca⁺⁺), an essential co-factor in the coagulation cascade, is associated with the severity of bleeding and the need for advanced interventions among these patients. This was a retrospective single-center cohort study of all patients admitted due to NV-UGIB. The primary outcome was transfusion of ≥ 2 packed red blood cells, arterial embolization, or emergency surgery. Secondary outcomes included (1) transfusion of ≥ 2 packed red blood cells, (2) arterial embolization, or emergency surgery, and (3) all-cause in-hospital mortality. Multivariable logistic regression was performed to determine whether Ca⁺⁺ was an independent predictor of these adverse outcomes. 1345 patients were included. Hypocalcemia was recorded in 604 (44.9%) patients. The rates of primary adverse outcome were significantly higher in the hypocalcemic group, 14.4% vs. 5.1%, p < 0.001. Secondary outcomes-multiple transfusions, need for angiography or surgery, and mortality were also increased (9.9% vs. 2.3%, p < 0.001, 5.3% vs. 2.8%, p = 0.03, and 33.3% vs. 24.7%, p < 0.001, respectively). Hypocalcemia was an independent predictor of primary and all the secondary outcomes, except mortality. Hypocalcemia in high-risk hospitalized patients with NV-UGIB is common and independently associated with adverse outcomes. Ca⁺⁺ monitoring in this population may facilitate the rapid identification of high-risk patients. Trials are needed to assess whether correction of hypocalcemia will lead to improved outcomes.

Consciousness depends on integration between parietal cortex, striatum, and thalamus

The neural substrates of consciousness remain elusive. Competing theories that attempt to explain consciousness disagree on the contribution of frontal versus posterior cortex and omit subcortical influences. This lack of understanding impedes the ability to monitor consciousness, which can lead to adverse clinical consequences. To test substrates and measures of consciousness, we recorded simultaneously from frontal cortex, parietal cortex, and subcortical structures, the striatum and thalamus, in awake, sleeping, and anesthetized macaques. We manipulated consciousness on a finer scale using thalamic stimulation, rousing macaques from continuously administered anesthesia. Our results show that, unlike measures targeting complexity, a measure additionally capturing neural integration (Φ∗) robustly correlated with changes in consciousness. Machine learning approaches show parietal cortex, striatum, and thalamus contributed more than frontal cortex to decoding differences in consciousness. These findings highlight the importance of integration between parietal and subcortical structures and challenge a key role for frontal cortex in consciousness.

Association Between Ionized Calcium Level and Neurological Outcome in Endovascularly Treated Patients with Spontaneous Subarachnoid Hemorrhage: A Retrospective Cohort Study

BACKGROUND

Spontaneous subarachnoid hemorrhage (SSAH) is associated with significant morbidity and mortality. Pathophysiological processes following initial bleeding are complex and not fully understood. In this study, we aimed to determine whether a low level of ionized calcium (Ca⁺⁺), an essential cofactor in the coagulation cascade and other cellular processes, is associated with adverse neurological outcome, development of early hydrocephalus, and symptomatic vasospasm among patients with SSAH.

METHODS

This was a retrospective single-center cohort study of all patients admitted for SSAH between January 1, 2009, and April 31, 2020. The primary outcome was an unfavorable neurological status at discharge, defined as a modified Rankin Scale score greater than or equal to 3. Secondary outcomes were the development of early hydrocephalus and symptomatic vasospasm. Multivariable logistic regression was performed to determine whether Ca⁺⁺ was an independent predictor of these outcomes.

RESULTS

A total of 255 patients were included in the final analysis. Hypocalcemia, older age, admission Glasgow Coma Scale (GCS) score, and admission Hunt-Hess classification scale (H&H) grades IV and V were independently associated with unfavorable neurological outcome, with adjusted odds ratios (ORs) of 1.93 (95% confidence interval [CI] 1.1-3.4; p = 0.02) for each 0.1 mmol L^-1 decrease in the Ca⁺⁺ level, 1.04 (95% CI 1.01-1.08; p = 0.02) for each year increase, 0.82 (95% CI 0.68-0.99; p = 0.04), and 6.29 (95% CI 1.14-34.6; p = 0.03), respectively. Risk factors for the development of hydrocephalus were hypocalcemia and GCS score, with ORs of 1.85 (95% CI 1.26-2.71; p = 0.002) for each 0.1 mmol L^-1 decrease in the Ca⁺⁺ level and 0.83 (95% CI 0.73-0.94; p = 0.005), respectively. Ca⁺⁺ was not associated with symptomatic vasospasm (OR 1.04 [95% CI 0.76-1.41]; p = 0.81). Among patients with admission H&H grade I-III bleeding, hypocalcemia was independently associated with unfavorable neurological outcome at discharge, with an adjusted OR of 1.99 (95% CI 1.03-3.84; p = 0.04) for each 0.1 mmol L^-1 decrease in the Ca⁺⁺ level. Hypocalcemia was also an independent risk factor for the development of early hydrocephalus, with an adjusted OR of 2.95 (95% CI 1.49-5.84; p = 0.002) for each 0.1 mmol L^-1 decrease in the Ca⁺⁺ level. Ca⁺⁺ was not associated with symptomatic vasospasm. No association was found between Ca⁺⁺ and predefined outcomes among patients with admission H&H grade IV and V bleeding.

CONCLUSIONS

Our study shows that hypocalcemia is associated with worse neurological outcome at discharge and development of early hydrocephalus in endovascularly treated patients with SSAH. Potential mechanisms include calcium-induced coagulopathy and higher blood pressure. Trials are needed to assess whether correction of hypocalcemia will lead to improved outcomes.

Association between ionised calcium and severity of postpartum haemorrhage: a retrospective cohort study

BACKGROUND

Postpartum haemorrhage (PPH) is often complicated by impaired coagulation. We aimed to determine whether the level of ionised calcium (Ca²⁺), an essential coagulation co-factor, at diagnosis of PPH is associated with bleeding severity.

METHODS

This was a retrospective cohort study of women diagnosed with PPH during vaginal delivery between January 2009 and April 2020. Ca²⁺ levels at PPH diagnosis were compared between women who progressed to severe PPH (primary outcome) and those with less severe bleeding. Severe PPH was defined by transfusion of ≥2 blood units, arterial embolisation or emergency surgery, admission to ICU, or death. Associations between other variables (e.g. fibrinogen concentration) and bleeding severity were also assessed.

RESULTS

For 436 patients included in the analysis, hypocalcaemia was more common among patients with severe PPH (51.5% vs 10.6%, P<0.001). In a multivariable logistic regression model, Ca²⁺ and fibrinogen were the only parameters independently associated with PPH severity with odds ratios of 1.14 for each 10 mg dl^-1 decrease in fibrinogen (95% confidence interval [CI], 1.05-1.24; P=0.002) and 1.97 for each 0.1 mmol L^-1 decrease in Ca²⁺ (95% CI, 1.25-3.1; P=0.003). The performance of Ca²⁺ or fibrinogen was not significantly different (area under the curve [AUC]=0.79 [95% CI, 0.75-0.83] vs AUC=0.86 [95% CI, 0.82-0.9]; P=0.09). The addition of Ca²⁺ to fibrinogen improved the model, leading to AUC of 0.9 (95% CI, 0.86-0.93), P=0.03.

CONCLUSIONS

Ca²⁺ level at the time of diagnosis of PPH was associated with risk of severe bleeding. Ca²⁺ monitoring may facilitate identification and treatment of high-risk patients.

Return to training in the COVID-19 era: The physiological effects of face masks during exercise

COVID-19 outbreak has a profound impact on almost every aspect of life. Universal masking is recommended as a means of source control. Routinely exercising in a safe environment is an important strategy for healthy living during this crisis. As sports clubs and public spaces may serve a source of viral transmission, masking may become an integral part of physical activity. This study aimed to assess the physiological effects of wearing surgical masks and N95 respirators during short-term strenuous workout. This was a multiple cross-over trial of healthy volunteers. Using a standard cycle ergometry ramp protocol, each subject performed a maximal exercise test without a mask, with a surgical mask, and with an N95 respirator. Physiological parameters and time to exhaustion were compared. Each subject served his own control. Sixteen male volunteers (mean age and BMI of 34 ± 4 years and 28.72 ± 3.78 kg/m² , respectively) completed the protocol. Heart rate, respiratory rate, blood pressure, oxygen saturation, and time to exhaustion did not differ significantly. Exercising with N95 mask was associated with a significant increase in end-tidal carbon dioxide (EtCO₂ ) levels. The differences were more prominent as the load increased, reaching 8 mm Hg at exhaustion (none vs N95, P = .001). In conclusion, in healthy subjects, short-term moderate-strenuous aerobic physical activity with a mask is feasible, safe, and associated with only minor changes in physiological parameters, particularly a mild increase in EtCO₂ . Subjects suffering from lung diseases should have a cautious evaluation before attempting physical activity with any mask.

Sedative drugs modulate the neuronal activity in the subthalamic nucleus of parkinsonian patients

Microelectrode recording (MER) is often used to identify electrode location which is critical for the success of deep brain stimulation (DBS) treatment of Parkinson’s disease. The usage of anesthesia and its’ impact on MER quality and electrode placement is controversial. We recorded neuronal activity at a single depth inside the Subthalamic Nucleus (STN) before, during, and after remifentanil infusion. The root mean square (RMS) of the 250–6000 Hz band-passed signal was used to evaluate the regional spiking activity, the power spectrum to evaluate the oscillatory activity and the coherence to evaluate synchrony between two microelectrodes. We compare those to new frequency domain (spectral) analysis of previously obtained data during propofol sedation. Results showed Remifentanil decreased the normalized RMS by 9% (P < 0.001), a smaller decrease compared to propofol. Regarding the beta range oscillatory activity, remifentanil depressed oscillations (drop from 25 to 5% of oscillatory electrodes), while propofol did not (increase from 33.3 to 41.7% of oscillatory electrodes). In the cases of simultaneously recorded oscillatory electrodes, propofol did not change the synchronization while remifentanil depressed it. In conclusion, remifentanil interferes with the identification of the dorsolateral oscillatory region, whereas propofol interferes with RMS identification of the STN borders. Thus, both have undesired effect during the MER procedure.

Trial registration: NCT00355927 and NCT00588926.

Optogenetic Activation of Afferent Pathways in Brain Slices and Modulation of Responses by Volatile Anesthetics

Anesthetics influence consciousness in part via their actions on thalamocortical circuits. However, the extent to which volatile anesthetics affect distinct cellular and network components of these circuits remains unclear. Ex vivo brain slices provide a means by which investigators may probe discrete components of complex networks and disentangle potential mechanisms underlying the effects of volatile anesthetics on evoked responses. To isolate potential cell type- and pathway-specific drug effects in brain slices, investigators must be able to independently activate afferent fiber pathways, identify non-overlapping populations of cells, and apply volatile anesthetics to the tissue in aqueous solution. In this protocol, methods to measure optogenetically-evoked responses to two independent afferent pathways to neocortex in ex vivo brain slices are described. Extracellular responses are recorded to assay network activity and targeted whole-cell patch clamp recordings are conducted in somatostatin- and parvalbumin-positive interneurons. Delivery of physiologically relevant concentrations of isoflurane via artificial cerebral spinal fluid to modulate cellular and network responses is described.

[ANESTHETIC DRUGS IN CHILDREN AND PREGNANT WOMEN - IMPLICATIONS OF THE RECENT FDA WARNING]

Recent animal studies demonstrated neuronal apoptosis following early life exposure to most anesthetic drugs. Further research into this question demonstrated neonatal neuronal damage in multiple species (including primates) and evidence that this damage has cognitive and social sequela. These results raised the suspicion that general anesthesia in neonates, infants and pregnant women may injure the developing brain. Follow-up human studies were inconclusive. Retrospective studies suffer from tremendous selection bias due to the surgical effect and the baseline condition that required the surgical intervention. A number of large retrospective studies yield contradicting results, leaving the issue unsettled. Results of new, high quality prospective studies suggest that a short, single exposure does not lead to any measurable damage, but we are still awaiting final long term results. Despite the inconclusive evidence, the American Food and Drug Administration (FDA) published a warning mandating drug manufacturers to disclose the risk with the package insert, and clinicians to discuss the possible risks with the parents or the pregnant woman before the planned procedure. The European Society of Anesthesiologists, as well as the Israeli Society of Anesthesiologists, did not adopt this FDA policy. Despite the possible uncertain risk, it was decided that the evidence is inconclusive in regards to clinical human scenarios. It was agreed that such warnings would lead to delaying necessary procedures based on unfounded information. It was therefore decided to avoid changing the informed consent form and consent process until further information is available.

[DIFFERENT ANESTHESIA APPROACHES IN THE TRANSCATHETER AORTIC VALVE IMPLANTATION (TAVI) PROCEDURE AND THEIR POSSIBLE EFFECT ON MORBIDITY AND MORTALITY]

BACKGROUND

Transcatheter aortic valve implantation (TAVI) is used in patients with severe aortic stenosis (AS) who are at high surgical risk. Pre- and post-operative management is challenging as these patients are older, have significant comorbidities and a very high expected mortality rate in conventional surgery. There is no consensus in the literature about the preferred form of anesthesia, however, currently most centers perform the procedure using local anesthesia with sedation (LA-S).

OBJECTIVES

To compare general anesthesia (GA) and LA-S in patients undergoing TAVI.

METHODS

A retrospective review of the first 100 patients who underwent TAVI (11/2008-6/2011) at the Rabin Medical Center, due to severe and symptomatic AS and a counter-indication for conventional valve replacement surgery.

RESULTS

A total of 46 patients underwent the procedure with GA and 54 with LA-S. In 63 patients, the transfemoral approach was used, transapical in 23, and transaxillary in 11. There were no significant differences in short- and long-term mortality, but average hospitalization was longer in the GA group. A larger proportion of patients needed norepinephrine and blood transfusions during the procedure in the GA group. In the LA-S group, more conduction, vascular complications and postoperative fever were observed. In comparisons between anesthesia methods with the transfemoral approach, most of the differences lost their significance. Therefore, these differences are most likely attributed to the surgical approach and not to the anesthesia method.

CONCLUSIONS

There is no clear preference for GA in TAVI. LA-S appears to be an effective and safe option for eligible patients.

Thalamus Modulates Consciousness via Layer-Specific Control of Cortex

Functional MRI and electrophysiology studies suggest that consciousness depends on large-scale thalamocortical and corticocortical interactions. However, it is unclear how neurons in different cortical layers and circuits contribute. We simultaneously recorded from central lateral thalamus (CL) and across layers of the frontoparietal cortex in awake, sleeping, and anesthetized macaques. We found that neurons in thalamus and deep cortical layers are most sensitive to changes in consciousness level, consistent across different anesthetic agents and sleep. Deep-layer activity is sustained by interactions with CL. Consciousness also depends on deep-layer neurons providing feedback to superficial layers (not to deep layers), suggesting that long-range feedback and intracolumnar signaling are important. To show causality, we stimulated CL in anesthetized macaques and effectively restored arousal and wake-like neural processing. This effect was location and frequency specific. Our findings suggest layer-specific thalamocortical correlates of consciousness and inform how targeted deep brain stimulation can alleviate disorders of consciousness.

Disruption of cortical network activity by the general anaesthetic isoflurane

Background

Actions of general anaesthetics on activity in the cortico-thalamic network likely contribute to loss of consciousness and disconnection from the environment. Previously, we showed that the general anaesthetic isoflurane preferentially suppresses cortically evoked synaptic responses compared with thalamically evoked synaptic responses, but how this differential sensitivity translates into changes in network activity is unclear.

Methods

We investigated isoflurane disruption of spontaneous and stimulus-induced cortical network activity using multichannel recordings in murine auditory thalamo-cortical brain slices.

Results

Under control conditions, afferent stimulation elicited short latency, presumably monosynaptically driven, spiking responses, as well as long latency network bursts that propagated horizontally through the cortex. Isoflurane (0.05-0.6 mM) suppressed spiking activity overall, but had a far greater effect on network bursts than on early spiking responses. At isoflurane concentrations >0.3 mM, network bursts were almost entirely blocked, even with increased stimulation intensity and in response to paired (thalamo-cortical + cortical layer 1) stimulation, while early spiking responses were <50% blocked. Isoflurane increased the threshold for eliciting bursts, decreased their propagation speed and prevented layer 1 afferents from facilitating burst induction by thalamo-cortical afferents.

Conclusions

Disruption of horizontal activity spread and of layer 1 facilitation of thalamo-cortical responses likely contribute to the mechanism by which suppression of cortical feedback connections disrupts sensory awareness under anaesthesia.

One-minute heart rate variability - an adjunct for airway obstruction identification

Heart rate variability (HRV) reflects cardiac and autonomic nervous system activity. It is usually measured over a relatively prolonged period and presented using multiple parameters. Here, we studied rapid HRV changes during airway obstruction using a short (1 min) sampling window. Forty healthy volunteers underwent a trial of obstructed breathing. Heart rate was recorded during three consecutive sets comprised of 1-min control followed by 1 min of obstructed breathing, with 1 min of rest between sets. Time and frequency domain analysis were used to compare HRV during control versus obstructed breathing. Compared with control, HRV intensely increased during obstructed breathing: R-R intervals (time between consecutive R waves) standard deviation increased from 65 to 108 msec (P < 0.0001), root mean square of successive R-R interval from 61 to 82 msec (P = 0.001), number of pairs of successive R-R intervals that differ by more than 50 msec (NN50) from 16.5 to 25.3 events (P < 0.0001), and proportion of NN50 divided by total number of R-R intervals from 26.6 to 35.1% (P = 0.001). Low frequency power increased by more than fourfold (P < 0.0001), allowing 90% sensitivity and 75% specificity for identifying airway obstruction (ROC area 0.88, P < 0.0001). We observed a rapid intense increase in HRV during obstructed breathing, significant enough to detect during a short 1-min sampling window. These findings suggest that HRV may be useful for rapid detection of airway obstruction, especially in situations where end-tidal CO2 monitoring is not optimal, such as during partial airway obstruction.

Propofol-induced unresponsiveness is associated with impaired feedforward connectivity in cortical hierarchy

BACKGROUND

Impaired consciousness has been associated with impaired cortical signal propagation after transcranial magnetic stimulation (TMS). We hypothesised that the reduced current propagation under propofol-induced unresponsiveness is associated with changes in both feedforward and feedback connectivity across the cortical hierarchy.

METHODS

Eight subjects underwent left occipital TMS coupled with high-density EEG recordings during wakefulness and propofol-induced unconsciousness. Spectral analysis was applied to responses recorded from sensors overlying six hierarchical cortical sources involved in visual processing. Dynamic causal modelling (DCM) of induced time-frequency responses and evoked response potentials were used to investigate propofol's effects on connectivity between regions.

RESULTS

Sensor space analysis demonstrated that propofol reduced both induced and evoked power after TMS in occipital, parietal, and frontal electrodes. Bayesian model selection supported a DCM with hierarchical feedforward and feedback connections. DCM of induced EEG responses revealed that the primary effect of propofol was impaired feedforward responses in cross-frequency theta/alpha-gamma coupling and within frequency theta coupling (F contrast, family-wise error corrected P<0.05). An exploratory analysis (thresholded at uncorrected P<0.001) also suggested that propofol impaired feedforward and feedback beta band coupling. Post hoc analyses showed impairments in all feedforward connections and one feedback connection from parietal to occipital cortex. DCM of the evoked response potential showed impaired feedforward connectivity between left-sided occipital and parietal cortex (T contrast P=0.004, Bonferroni corrected).

CONCLUSIONS

Propofol-induced loss of consciousness is associated with impaired hierarchical feedforward connectivity assessed by EEG after occipital TMS.

Testosterone Potentiation of Ionophore and ADP Induced Platelet Aggregation : Relationship to Arachidonic Acid Metabolism

The role of arachidonic acid oxygenated products in human platelet aggregation induced by the ionophore A23187 was investigated. The ionophore produced an increased release of both saturated and unsaturated fatty acids and a concomitant increased formation of TxA2 and other arachidonate products. TxA2 (and possibly other cyclo oxygenase products) appears to have a significant role in ionophore-induced aggregation only when low concentrations (<1 μM) of the ionophore are employed.

Testosterone added to rat or human platelet-rich plasma (PRP) was shown previously to potentiate platelet aggregation induced by ADP, adrenaline, collagen and arachidonic acid (1, 2). We show that testosterone also potentiates ionophore induced aggregation in washed platelets and in PRP. This potentiation was dose and time dependent and resulted from increased lipolysis and concomitant generation of TxA2 and other prostaglandin products. The testosterone potentiating effect was abolished by preincubation of the platelets with indomethacin.

Comparison of the performance of battery-operated fluid warmers

Objectives

Warming intravenous fluids is essential to prevent hypothermia in patients with trauma, especially when large volumes are administered. Prehospital and transport settings require fluid warmers to be small, energy efficient and independent of external power supply. We compared the warming properties and resistance to flow of currently available battery-operated fluid warmers.

Methods

Fluid warming was evaluated at 50, 100 and 200 mL/min at a constant input temperature of 20°C and 10°C using a cardiopulmonary bypass roller pump and cooler. Output temperature was continuously recorded.

Results

Performance of fluid warmers varied with flows and input temperatures. At an input temperature of 20°C and flow of 50 mL/min, the Buddy Lite, enFlow, Thermal Angel and Warrior warmed 3.4, 2.4, 1 and 3.6 L to over 35°C, respectively. However, at an input temperature of 10°C and flow of 200 mL/min, the Buddy Lite failed to warm, the enFlow warmed 3.3 L to 25.7°C, the Thermal Angel warmed 1.5 L to 20.9°C and the Warrior warmed 3.4 L to 34.4°C (p<0.0001).

Conclusion

We found significant differences between the fluid warmers: the use of the Buddy Lite should be limited to moderate input temperature and low flow rates. The use of the Thermal Angel is limited to low volumes due to battery capacity and low output temperature at extreme conditions. The Warrior provides the best warming performance at high infusion rates, as well as low input temperatures, and was able to warm the largest volumes in these conditions.

Ketamine induced converged synchronous gamma oscillations in the cortico-basal ganglia network of nonhuman primates

N-methyl-d-aspartate (NMDA) antagonists are widely used in anesthesia, pain management, and schizophrenia animal model studies, and recently as potential antidepressants. However, the mechanisms underlying their anesthetic, psychotic, cognitive, and emotional effects are still elusive. The basal ganglia (BG) integrate input from different cortical domains through their dopamine-modulated connections to achieve optimal behavior control. NMDA antagonists have been shown to induce gamma oscillations in human EEG recordings and in rodent cortical and BG networks. However, network relations and implications to the primate brain are still unclear. We recorded local field potentials (LFPs) simultaneously from the primary motor cortex (M1) and the external globus pallidus (GPe) of four vervet monkeys (26 sessions, 97 and 76 cortical and pallidal LFPs, respectively) before and after administration of ketamine (NMDA antagonist, 10 mg/kg im). Ketamine induced robust, spontaneous gamma (30-50 Hz) oscillations in M1 and GPe. These oscillations were initially modulated by ultraslow oscillations (~0.3 Hz) and were highly synchronized within and between M1 and the GPe (mean coherence magnitude = 0.76, 0.88, and 0.41 for M1-M1, GPe-GPe, and M1-GPe pairs). Phase differences were distributed evenly around zero with broad and very narrow distribution for the M1-M1 and GPe-GPe pairs (-3.5 ± 31.8° and -0.4 ± 6.0°), respectively. The distribution of M1-GPe phase shift was skewed to the left with a mean of -18.4 ± 20.9°. The increased gamma coherence between M1 and GPe, two central stages in the cortico-BG loops, suggests a global abnormal network phenomenon with a unique spectral signature, which is enabled by the BG funneling architecture.NEW & NOTEWORTHY This study is the first to show spontaneous gamma oscillations under NMDA antagonist in nonhuman primates. These oscillations appear in synchrony in the cortex and the basal ganglia. Phase analysis refutes the confounding effects of volume conduction and supports the funneling and amplifying architecture of the cortico-basal ganglia loops. These results suggest an abnormal network phenomenon with a unique spectral signature that could account for pathological mental and neurological states.

Morphological and Molecular Characteristic of Megaselia scalaris (Diptera: Phoridae) Larvae as the Cause of Urinary Myiasis

We report a case of urinary myiasis occurring in a 60-yr-old Iranian male patient with urinary tract problems and a history of travel to Thailand who was referred to Shafagh Medical Laboratory in Tehran (Iran). Larvae excreted in the patient's urine were confirmed by morphological identification key and DNA barcoding to belong to the species Megaselia scalaris Loew, which is known as the scuttle fly. Based on the patient's history, he was infected with M. scalaris in Thailand. To the best of our knowledge, this is the first report of urinary myiasis caused by M. scalaris in Thailand.

Inhibition of malignant thyroid carcinoma cell proliferation by Ras and galectin-3 inhibitors

Anaplastic Thyroid carcinoma is an extremely aggressive solid tumor that resists most treatments and is almost always fatal. Galectin-3 (Gal-3) is an important marker for thyroid carcinomas and a scaffold of the K-Ras protein. S-trans, transfarnesylthiosalicylic acid (FTS; Salirasib) is a Ras inhibitor that inhibits the active forms of Ras proteins. Modified citrus pectin (MCP) is a water-soluble citrus-fruit-derived polysaccharide fiber that specifically inhibits Gal-3. The aim of this study was to develop a novel drug combination designed to treat aggressive anaplastic thyroid carcinoma. Combined treatment with FTS and MCP inhibited anaplastic thyroid cells proliferation in vitro by inducing cell cycle arrest and increasing apoptosis rate. Immunoblot analysis revealed a significant decrease in Pan-Ras, K-Ras, Ras-GTP, p-ERK, p53, and Gal-3 expression levels and significant increase in p21 expression levels. In nude mice, treatment with FTS and MCP inhibited tumor growth. Levels of Gal-3, K-Ras-GTP, and p-ERK were significantly decreased. To conclude, our results suggest K-Ras and Gal-3 as potential targets in anaplastic thyroid tumors and herald a novel treatment for highly aggressive anaplastic thyroid carcinoma.

The Anopheles stephensi odorant binding protein 1 (AsteObp1) gene: a new molecular marker for biological forms diagnosis

Anopheles (Cellia) stephensi Liston 1901 is known as an Asian malaria vector. Three biological forms, namely "mysorensis", "intermediate", and "type" have been earlier reported in this species. Nevertheless, the present morphological and molecular information is insufficient to diagnose these forms. During this investigation, An. stephensi biological forms were morphologically identified and sequenced for odorant-binding protein 1 (Obp1) gene. Also, intron I sequences were used to construct phylogenetic trees. Despite nucleotide sequence variation in exon of AsteObp1, nearly 100% identity was observed at the amino acid level among the three biological forms. In order to overcome difficulties in using egg morphology characters, intron I sequences of An. stephensi Obp1 opens new molecular way to the identification of the main Asian malaria vector biological forms. However, multidisciplinary studies are needed to establish the taxonomic status of An. stephensi.

Preferential effect of isoflurane on top-down vs. bottom-up pathways in sensory cortex

The mechanism of loss of consciousness (LOC) under anesthesia is unknown. Because consciousness depends on activity in the cortico-thalamic network, anesthetic actions on this network are likely critical for LOC. Competing theories stress the importance of anesthetic actions on bottom-up “core” thalamo-cortical (TC) vs. top-down cortico-cortical (CC) and matrix TC connections. We tested these models using laminar recordings in rat auditory cortex in vivo and murine brain slices. We selectively activated bottom-up vs. top-down afferent pathways using sensory stimuli in vivo and electrical stimulation in brain slices, and compared effects of isoflurane on responses evoked via the two pathways. Auditory stimuli in vivo and core TC afferent stimulation in brain slices evoked short latency current sinks in middle layers, consistent with activation of core TC afferents. By contrast, visual stimuli in vivo and stimulation of CC and matrix TC afferents in brain slices evoked responses mainly in superficial and deep layers, consistent with projection patterns of top-down afferents that carry visual information to auditory cortex. Responses to auditory stimuli in vivo and core TC afferents in brain slices were significantly less affected by isoflurane compared to responses triggered by visual stimuli in vivo and CC/matrix TC afferents in slices. At a just-hypnotic dose in vivo, auditory responses were enhanced by isoflurane, whereas visual responses were dramatically reduced. At a comparable concentration in slices, isoflurane suppressed both core TC and CC/matrix TC responses, but the effect on the latter responses was far greater than on core TC responses, indicating that at least part of the differential effects observed in vivo were due to local actions of isoflurane in auditory cortex. These data support a model in which disruption of top-down connectivity contributes to anesthesia-induced LOC, and have implications for understanding the neural basis of consciousness.

Spiking in auditory cortex following thalamic stimulation is dominated by cortical network activity

The state of the sensory cortical network can have a profound impact on neural responses and perception. In rodent auditory cortex, sensory responses are reported to occur in the context of network events, similar to brief UP states, that produce "packets" of spikes and are associated with synchronized synaptic input (Bathellier et al., 2012; Hromadka et al., 2013; Luczak et al., 2013). However, traditional models based on data from visual and somatosensory cortex predict that ascending sensory thalamocortical (TC) pathways sequentially activate cells in layers 4 (L4), L2/3, and L5. The relationship between these two spatio-temporal activity patterns is unclear. Here, we used calcium imaging and electrophysiological recordings in murine auditory TC brain slices to investigate the laminar response pattern to stimulation of TC afferents. We show that although monosynaptically driven spiking in response to TC afferents occurs, the vast majority of spikes fired following TC stimulation occurs during brief UP states and outside the context of the L4>L2/3>L5 activation sequence. Specifically, monosynaptic subthreshold TC responses with similar latencies were observed throughout layers 2-6, presumably via synapses onto dendritic processes located in L3 and L4. However, monosynaptic spiking was rare, and occurred primarily in L4 and L5 non-pyramidal cells. By contrast, during brief, TC-induced UP states, spiking was dense and occurred primarily in pyramidal cells. These network events always involved infragranular layers, whereas involvement of supragranular layers was variable. During UP states, spike latencies were comparable between infragranular and supragranular cells. These data are consistent with a model in which activation of auditory cortex, especially supragranular layers, depends on internally generated network events that represent a non-linear amplification process, are initiated by infragranular cells and tightly regulated by feed-forward inhibitory cells.

Subthalamic nucleus long-range synchronization-an independent hallmark of human Parkinson's disease

Beta-band synchronous oscillations in the dorsolateral region of the subthalamic nucleus (STN) of human patients with Parkinson's disease (PD) have been frequently reported. However, the correlation between STN oscillations and synchronization has not been thoroughly explored. The simultaneous recordings of 2390 multi-unit pairs recorded by two parallel microelectrodes (separated by fixed distance of 2 mm, n = 72 trajectories with two electrode tracks >4 mm STN span) in 57 PD patients undergoing STN deep brain stimulation surgery were analyzed. Automatic procedures were utilized to divide the STN into dorsolateral oscillatory and ventromedial non-oscillatory regions, and to quantify the intensity of STN oscillations and synchronicity. Finally, the synchronicity of simultaneously vs. non-simultaneously recorded pairs were compared using a shuffling procedure. Synchronization was observed predominately in the beta range and only between multi-unit pairs in the dorsolateral oscillatory region (n = 615). In paired recordings between sites in the dorsolateral and ventromedial (n = 548) and ventromedial-ventromedial region pairs (n = 1227), no synchronization was observed. Oscillation and synchronicity intensity decline along the STN dorsolateral-ventromedial axis suggesting a fuzzy border between the STN regions. Synchronization strength was significantly correlated to the oscillation power, but synchronization was no longer observed following shuffling. We conclude that STN long-range beta oscillatory synchronization is due to increased neuronal coupling in the Parkinsonian brain and does not merely reflect the outcome of oscillations at similar frequency. The neural synchronization in the dorsolateral (probably the motor domain) STN probably augments the pathological changes in firing rate and patterns of subthalamic neurons in PD patients.

The significance of galectin-3 as a new basal cell marker in prostate cancer

Prostate cancer may originate from distinct cell types, resulting in the heterogeneity of this disease. Galectin-3 (Gal-3) and androgen receptor (AR) have been reported to play important roles in the progression of prostate cancer, and their heterogeneous expressions might be associated with different cancer subtypes. Our study found that in various prostate cancer cell lines Gal-3 expression was always opposite to AR expression and other luminal cell markers but consistent with basal cell markers including glutathione S-transferase-π and Bcl-2. This expression pattern was confirmed in human prostate cancer tissues. Our results also showed that prostate cancer cells positive with basal cell markers were more aggressive. Downregulation of Gal-3 expression resulted in increased apoptotic potential and decreased metastasis potential of prostate cancer cells. Our findings demonstrate for the first time that Gal-3 may serve as a new marker for basal characteristics of prostate cancer epithelium. This study helps us to better understand the heterogeneity of prostate cancer. The clinical significance of this study lies in the application of Gal-3 to distinguish prostate cancer subtypes and improve treatment efficacy with designed personalized therapy.

Psychosocial factors and chronic spontaneous urticaria: a systematic review

BACKGROUND

Chronic spontaneous urticaria (CSU) is one of the most costly allergic conditions challenging physicians as well as patients and their families. Despite evident lacunae in the understanding of the pathogenesis, at least some findings suggest that psychosocial factors likely contribute to the development and exacerbation of CSU. We aim to assess the contribution of psychological factors to CSU.

METHODS

Systematic search of PubMed and OVID/Medline databases was conducted from 1 January 1935 to 1 January 2012. Studies selected include original research in English, Spanish and French exploring the association between CSU and psychosocial factors. Two investigators independently reviewed all titles and abstracts to identify potentially relevant articles and resolved discrepancies by repeated review and discussion and arbitration of a third reviewer. Quality of systematic reviews and meta-analyses was assessed using a measure based on the Newcastle-Ottawa Scale and psychological conditions of CSU patients.

RESULTS

We identified 114 eligible studies spanning 77 years and featuring 17 reviews, 67 studies related to neither CSU nor psychosocial factors, and eight studies that provided either no prevalence estimates or insufficient sample size. Pooling effect sizes using random effects, analyses revealed that, despite large heterogeneity (I(2) of 97.60%), psychosocial factors had a prevalence of 46.09% (95% confidence interval, 44.01%, 48.08%).

CONCLUSION

Future research needs to better establish the contribution of psychosocial factors to the pathogenesis and exacerbation of CSU, and explore the possible benefit of behavioural interventions to the development of new management strategies.

Autocrine motility factor and its receptor expressions in human oral squamous cell carcinoma (SCC) cells

Autocrine motility factor (AMF) a tumor-secreted 55 kDa cytokine induces tumor cell motility by a signal transduction pathway mediated by interaction with its receptor (AMFR) a cell surface glycoprotein of 78 kDa (gp78). Here, AMF secreted by the metastatic LMF4 human oral squamous-cell carcinoma (SCC) cells, induced dose- and time-dependent morphological changes and chemotaxis of the producing cells. Expression of AMFR mRNA was associated with the metastatic ability of SCC cell variants. The data presented show for the first time that SCC cells produce AMF and express AMFR and the expression is related to their invasiveness and metastatic potentials.

Induction of tumorigenicity by galectin-3 in a nontumorigenic human breast-carcinoma cell-line

The human galectin-3 is a galactoside-binding protein of 31 kDa which functions as a receptor for glycoproteins containing poly N-acetyllactosamine side chains and as a substrate for matrix metalloproteinases-2 and -9. We studied its expression by flow cytoflourimetry, Western, Northern and Southern analyses, in five cultured human breast carcinoma cell lines previously characterized as nontumorigenic, poorly metastatic or metastatic in nude mice. The expression of galectin-3 correlated with the reported tumorigenicity of the cells. The introduction of recombinant galectin-3 into the null expressing non-tumorigenic BT-549 cells resulted in the acquisition of anchorage-independent growth properties in all and tumorigenicity in 3/4 sense transfected cell clones. The data indicate a relationship between galectin-3 expression and malignancy of human breast carcinoma cell lines.

Calpain activation through galectin-3 inhibition sensitizes prostate cancer cells to cisplatin treatment

Prostate cancer will develop chemoresistance following a period of chemotherapy. This is due, in part, to the acquisition of antiapoptotic properties by the cancer cells and, therefore, development of novel strategies for treatment is of critical need. Here, we attempt to clarify the role of the antiapoptotic molecule galectin-3 in prostate cancer cells using siRNA and antagonist approaches. The data showed that Gal-3 inhibition by siRNA or its antagonist GCS-100/modified citrus pectin (MCP) increased cisplatin-induced apoptosis of PC3 cells. Recent studies have indicated that cisplatin-induced apoptosis may be mediated by calpain, a calcium-dependent protease, as its activation leads to cleavage of androgen receptor into an androgen-independent isoform in prostate cancer cells. Thus, we examined whether calpain activation is associated with the Gal-3 function of regulating apoptosis. Here, we report that Gal-3 inhibition by siRNA or GCS-100/MCP enhances calpain activation, whereas Gal-3 overexpression inhibits it. Inhibition of calpain using its inhibitor and/or siRNA attenuated the proapoptotic effect of Gal-3 inhibition, suggesting that calpain activation may be a novel mechanism for the proapoptotic effect of Gal-3 inhibition. Thus, a paradigm shift for treating prostate cancer is suggested whereby a combination of a non-toxic anti-Gal-3 drug together with a toxic chemotherapeutic agent could serve as a novel therapeutic modality for chemoresistant prostate cancers.

Propofol decreases neuronal population spiking activity in the subthalamic nucleus of Parkinsonian patients

BACKGROUND

Implantation of deep brain stimulation (DBS) electrodes in the subthalamic nucleus (STN) for the treatment of Parkinson disease is often performed using microelectrode recording (MER) of STN population spike activity. The extent to which sedative drugs interfere with MER is unknown. We recorded the population activity of STN neurons during propofol sedation and examined its effect on neuronal activity.

METHODS

The procedure was performed during DBS surgery for Parkinson disease. We administered propofol (50 μg/kg/min) at a constant electrode location in the STN until stable sedation was achieved. We recorded the electrical activity, and calculated its root mean square (RMS) before, during, and after the propofol infusions.

RESULTS

The activity of 24 electrode trajectories was recorded in 16 patients. The RMS of STN activity decreased significantly after propofol administration in 18 of the 24 trajectories. The average normalized RMS decreased by 23.2%± 9.1% (mean ± SD) during propofol administration (P < 0.001), and returned to baseline 9.3 ± 4.0 minutes after it was stopped.

CONCLUSIONS

Propofol administration leads to a significant decrease of STN neuronal activity. Thus, it may interfere with MER identification of the STN borders. However, activity returns to baseline shortly after administration stops. Therefore, propofol can be safely used until shortly before MER for DBS.