Molecular signatures of cortical expansion in the human fetal brain

The third trimester of human gestation is characterised by rapid increases in brain volume and cortical surface area. A growing catalogue of cells in the prenatal brain has revealed remarkable molecular diversity across cortical areas.1,2 Despite this, little is known about how this translates into the patterns of differential cortical expansion observed in humans during the latter stages of gestation. Here we present a new resource, μBrain, to facilitate knowledge translation between molecular and anatomical descriptions of the prenatal developing brain. Built using generative artificial intelligence, μBrain is a three-dimensional cellular-resolution digital atlas combining publicly-available serial sections of the postmortem human brain at 21 weeks gestation3 with bulk tissue microarray data, sampled across 29 cortical regions and 5 transient tissue zones.4 Using μBrain, we evaluate the molecular signatures of preferentially-expanded cortical regions during human gestation, quantified in utero using magnetic resonance imaging (MRI). We find that differences in the rates of expansion across cortical areas during gestation respect anatomical and evolutionary boundaries between cortical types5 and are founded upon extended periods of upper-layer cortical neuron migration that continue beyond mid-gestation. We identify a set of genes that are upregulated from mid-gestation and highly expressed in rapidly expanding neocortex, which are implicated in genetic disorders with cognitive sequelae. Our findings demonstrate a spatial coupling between areal differences in the timing of neurogenesis and rates of expansion across the neocortical sheet during the prenatal epoch. The μBrain atlas is available from: https://garedaba.github.io/micro-brain/ and provides a new tool to comprehensively map early brain development across domains, model systems and resolution scales.

Preferences of Patients and Providers in High-Burden Malaria Settings for Long-Acting Malaria Chemoprevention

Antimalarial medications are recommended for chemoprevention as part of malaria control programs to decrease the morbidity and mortality related to more than 200 million infections each year. We sought to evaluate patient and provider acceptability of malaria chemoprevention in a long-acting formulation. We administered questionnaires to patients and providers in malaria endemic districts in Kenya and Zambia. Questions explored preferences and concerns around long-acting antimalarial formulations compared with oral formulations. We recruited 202 patient respondents (Kenya, n = 102; Zambia, n = 100) and 215 provider respondents (Kenya, n = 105; Zambia, n = 110). Long-acting injection was preferred to oral pills, whereas oral pills were preferred to implant or transdermal administration by patient respondents. Of 202 patient respondents, 80% indicated that they 'definitely would try' malaria chemoprevention offered by injection instead of oral pills. Of parents or guardians, 84% of 113 responded that they 'definitely would' have their child age < 12 years and 90% of 88 'definitely would' have their child ≥12 years receive an injection for malaria prevention. Provider respondents indicated that they would be more likely to prescribe a long-acting injectable product compared with an oral product for malaria chemoprevention in adults (70%), adolescents ages 12 years and older (67%), and children <12 years (81%). Potential for prolonged adverse effects with long-acting products was the highest concern for patient respondents, while higher medication-related cost was cited as the most concerning barrier to implementation by providers. Overall, these findings indicate enthusiasm for the development of long-acting injectable antimalarials to provide individual delivery method options across age groups.

Longitudinal and Cross-sectional Analyses of Asymptomatic HIV-1/Malaria Co-infection in Kisumu County, Kenya

Individuals infected with HIV-1 experience more frequent and more severe episodes of malaria and are likely to harbor asymptomatic parasitemia, thus potentially making them more efficient reservoirs of malaria. Two studies (cross-sectional and longitudinal) were designed in sequence between 2015-2018 and 2018-2020, respectively, to test the hypothesis that HIV-1 infected individuals have higher prevalence of asymptomatic parasitemia and gametocytemia than the HIV-1 negatives. This article describes the overall design of the two studies, encompassing data for the longitudinal study and additional data to the previously published baseline data for the cross-sectional study. In the cross-sectional study, HIV-1 positive participants were significantly older, more likely to be male, and more likely to have parasitemia relative to HIV-1 negatives (P < 0.01). In the longitudinal study, 300 participants were followed for 6 months. Of these, 102 were HIV-1 negative, 106 were newly diagnosed HIV-1 positive, and 92 were HIV-1 positive and on antiretroviral therapy, including antifolates, at enrollment. Overall parasitemia positivity at enrollment was 17.3% (52/300). Of these, 44% (23/52) were HIV-1 negative, 52% (27/52) were newly diagnosed HIV-1 positives, and only 4% (2/52) were HIV-1 positive and on treatment. Parasitemia for those on stable antiretroviral therapy was significantly lower (hazard ratio: 0.51, P < 0.001), compared with the HIV-1-negatives. On follow-up, there was a significant decline in parasitemia prevalence (hazard ratio: 0.74, P < 0.001) among the HIV patients newly initiated on antiretroviral therapy including trimethoprim-sulfamethoxasole. These data highlight the impact of HIV-1 and HIV treatment on asymptomatic parasitemia over time.

Initiation of anti-retroviral/Trimethoprim-Sulfamethoxazole therapy in a longitudinal cohort of HIV-1 positive individuals in Western Kenya rapidly decreases asymptomatic malarial parasitemia

Interactions between malaria and HIV-1 have important public health implications. Our previous cross-sectional studies showed significant associations between HIV-1 positivity and malarial parasitemia with an increased risk of gametocytemia. In this follow-up longitudinal study, we evaluated these associations to determine the magnitude of asymptomatic parasitemia over time, and to examine the effects of initiating Antiretroviral Therapy (ART) together with the broad-spectrum antibiotic Trimethoprim Sulfamethoxazole (TS) on asymptomatic parasitemia. 300 adult volunteers in a malaria holoendemic region in Western Kenya were enrolled and followed for six months. The study groups were composed of 102 HIV-1 negatives, 106 newly diagnosed HIV-1 positives and 92 HIV-1 positives who were already stable on ART/TS. Blood samples were collected monthly and asymptomatic malarial parasitemia determined using sensitive 18S qPCR. Results showed significantly higher malaria prevalence in the HIV-1 negative group (61.4%) (p=0.0001) compared to HIV-1 positives newly diagnosed (36.5%) and those stable on treatment (31.45%). Further, treatment with ART/TS had an impact on incidence of asymptomatic parasitemia. In volunteers who were malaria PCR-negative at enrollment, the median time to detectable asymptomatic infection was shorter for HIV-1 negatives (149 days) compared to the HIV-1 positives on treatment (171 days) (p=0.00136). Initiation of HIV treatment among the newly diagnosed led to a reduction in malarial parasitemia (expressed as 18S copy numbers/μl) by over 85.8% within one week of treatment and a further reduction by 96% after 2 weeks. We observed that while the impact of ART/TS on parasitemia was long term, treatment with antimalarial Artemether/Lumefantrine (AL) among the malaria RDT positives had a transient effect with individuals getting re-infected after short periods. As was expected, HIV-1 negative individuals had normal CD4+ levels throughout the study. However, CD4+ levels among HIV-1 positives who started treatment were low at enrollment but increased significantly within the first month of treatment. From our association analysis, the decline in parasitemia among the HIV-1 positives on treatment was attributed to TS treatment and not increased CD4+ levels per se. Overall, this study highlights important interactions between HIV-1 and malaria that may inform future use of TS among HIV-infected patients in malaria endemic regions.

The CINAMR (Clinical Information Network-Antimicrobial Resistance) Project: A pilot microbial surveillance using hospitals linked to regional laboratories in Kenya: Study Protocol

Background: Antimicrobial resistance (AMR) is a global threat and is thought to be acute in low-and middle-income country (LMIC) settings, including in Kenya, but there is limited unbiased surveillance that can provide reliable estimates of its burden. Current efforts to build capacity for microbiology testing in Kenya are unlikely to result in systematic routine microbiological testing in the near term. Therefore, there is little prospect for microbiological support to inform clinical diagnoses nor for indicating the burden of AMR and for guiding empirical choice of antibiotics. Objective: We aim to build on an existing collaboration, the Clinical Information Network (CIN), to pilot microbiological surveillance using a 'hub-and-spoke' model where selected hospitals are linked to high quality microbiology research laboratories. Methods: Children admitted to paediatric wards of 12 participating hospitals will have a sample taken for blood culture at admission before antibiotics are started. Indication for blood culture will be a clinician's prescription of antibiotics. Samples will then be transported daily to the research laboratories for culture and antibiotic susceptibility testing and results relayed back to clinicians for patient management. The surveillance will take place for 6 months in each hospital. Separately, we shall conduct semi-structured interviews with frontline health workers to explore the feasibility and utility of this approach. We will also seek to understand how the availability of microbiology results might inform antibiotic stewardship, and as an interim step to the development of better national or regional laboratories linked to routine surveillance. Conclusions: If feasible, this approach is less costly and periodic 'hub-and-spoke' surveillance can be used to track AMR trends and to broadly guide empirical antibiotic guidance meaning it is likely to be more sustainable than establishing functional microbiological facilities in each hospital in a LMIC setting.

1049. Minimal Transient HIV-1 Viremia Following Vaccination Regimens Containing AD26. ZEBOV and MVA-BN-Filo in ART-Suppressed People Living with HIV

Background

Ebola Virus Disease (EVD) outbreaks primarily occur in the HIV endemic setting of Sub-Saharan Africa. Transient increases in HIV viral load (VL), or blips, have been described following routine vaccinations. We characterized VL blips among PLWH enrolled in a phase 2 trial of a heterologous two-dose EVD vaccine.

Methods

In EBL2003, adult participants with and without HIV were randomized 1:4 to receive placebo or vaccine. Part A in the US studied MVA-BN-Filo followed by Ad26.ZEBOV 14 days later. Part B in Africa evaluated this MVA/Ad26 regimen and also a schedule of Ad26.ZEBOV followed by MVA-BN-Filo 29 days later. VL was assessed at screening, pre-vaccination, and 21, 42, 180, and 365 days post dose 2. Participants with VL < 20 copies/mL at the first 2 visits who received both doses and had complete VL data through 42 days post dose 2 were evaluated. Blips were defined as a post-injection VL ≥ 20 copies/mL no later than 42 days post dose 2, with subsequent return to VL < 20 copies/mL.

Results

A total of 277 PLWH on antiretroviral therapy (ART) were assessed; 73.3% (203) had baseline virologic suppression, and 89.2% (181) of those received both doses with complete VL data for inclusion in the analysis. Overall, 19.9% (36) experienced blips: 20.0% (29) of vaccinees vs 19.4% (7) of placebo recipients (p=1.0). All baseline suppressed participants with post-injection viremia subsequently regained suppression. Among vaccinees, the mean blip VL was 192 copies/mL, and the mean blip duration was 56 days, which was not significantly different from placebo. Of all blips, only 2 were > 1,000 copies/mL. Blips occurred in 24.0% (25) of Ad26/MVA recipients, and 9.7% (4) of MVA/Ad26 recipients (p=0.07). A dose of Ad26 was associated with a blip in 6.9% (10) of recipients vs 13.1% (19) for MVA recipients (p=0.12). Regardless of regimen, dose 1 was associated with a blip in 8.3% (12) of vaccinees, compared to 11.7% (17) of vaccinees for dose 2 (p=0.43).

Conclusion

Among successfully treated PLWH, we observed low magnitude post-dose HIV blips that were not more common in vaccine vs. placebo recipients and did not result in loss of virologic suppression. This data is favorable for the deployment of the EVD vaccines in this trial in areas of high HIV endemicity.

Disclosures

Benjamin L. Custer, M.D., Alexion Pharmaceuticals (Shareholder)Armata Pharmaceuticals (Shareholder)Biomarin Pharmaceutical (Shareholder)Crispr Therapeutics (Shareholder)CVS Health Corp (Shareholder)Editas Medicine (Shareholder)Gilead (Shareholder)Glaxo Smith Kline (Shareholder)Hologic Inc (Shareholder)Merck (Shareholder)Mesoblast LTD (Shareholder)Pfizer (Shareholder)Sanofi (Shareholder)Unitedhealth Group (Shareholder)Vertex Pharmaceuticals (Shareholder) Georgi Shukarev, MD, Janssen (Employee) Auguste Gaddah, PhD, Janssen Pharmaceutica N.V (Employee) Kerstin Luhn, PhD, Janssen Vaccines and Prevention (Employee, Shareholder) Macaya Douoguih, MD, MPH, Janssen (Employee) Cynthia Robinson, MD, Janssen Vaccines (Employee)

Impact of comorbidities and ablation strategy on outcome after pulmonary vein isolation with cryo-balloon in patients with non- paroxysmal atrial fibrillation

Background

Presence of several comorbidities in patients with atrial fibrillation is well known, but impact of them on outcome after pulmonary vein isolation with cryo-balloon is not enough investigated. First aim of the study was analysis of the impact of comorbidities on long term outcome after PVI with cryo-balloon new generation (CBA) and secondary goal was evaluation of the impact of additional posterior roof ablation (PRA) in these patients.

Methods

Patients with non-paroxysmal AF ablated with CBA in our institution since May 2012 and completed follow up &gt;3 months were enrolled in the study. The history of AF, cardiac comorbidities (CAD, Non ischemic-cardiomyopathy, heart insufficiency, right ventricular dysfunction) diabetes mellitus, and renal failure were assessed at admission, all patients received echocardiographic examination and blood test.

After a single trans-septal access and PV angiography PVI was performed using a 28-mm CBA. Mapping of PV signals before, during, and after each cryo application was performed with a 3F lasso catheter. The procedural endpoint after PVI was defined as complete elimination of all fragmented signals at the PV antrum with verification of entrance and exit block. In some patients PRA was performed additionally to PVI at discretion of physician. The primary endpoint of this study was the first documented recurrence of atrial tachyarrhythmia (&gt;30 sec.), hospitalization due to cardio-vascular cause, re-do procedure or re-administration of anti-arrhythmic drugs.

Results

Among 560 patients 78 (13.9%) had no comorbidity and 299 (53.4%) were lasted with &gt;1 comorbidity. A total of 260 (46.4%) recurrences were obtained within median follow up of 28 (12–57) months. Female gender, long time from first diagnosis &gt;12 months and cardiac comorbidity were revealed to be independent predictors for long term recurrences whereas additional PRA performed in 176 pts independently improved outcome (61.9% vs 49.7%).

Conclusion

Cardiac comorbidities increased probability of post ablation recurrences, but performing of additional posterior roof ablation improved outcome in our cohort. These results should be confirmed in multi-center randomized study

Funding Acknowledgement

Type of funding sources: None.

Serological profiles of pan-coronavirus-specific responses in COVID-19 patients using a multiplexed electro-chemiluminescence-based testing platform

Serological assessment of SARS-CoV-2 specific responses are an essential tool for determining the prevalence of past SARS-CoV-2 infections in the population especially when testing occurs after symptoms have developed and limited contact tracing is in place. The goal of our study was to test a new 10-plex electro-chemiluminescence-based assay to measure IgM and IgG responses to the spike proteins from multiple human coronaviruses including SARS-CoV-2, assess the epitope specificity of the SARS-CoV-2 antibody response against full-length spike protein, receptor-binding domain and N-terminal domain of the spike protein, and the nucleocapsid protein. We carried out the assay on samples collected from three sample groups: subjects diagnosed with COVID-19 from the U.S. Army hospital at Camp Humphreys in Pyeongtaek, South Korea; healthcare administrators from the same hospital but with no reported diagnosis of COVID-19; and pre-pandemic samples. We found that the new CoV-specific multiplex assay was highly sensitive allowing plasma samples to be diluted 1:30,000 with a robust signal. The reactivity of IgG responses to SARS-CoV-2 nucleocapsid protein and IgM responses to SARS-CoV-2 spike protein could distinguish COVID-19 samples from non-COVID-19 and pre-pandemic samples. The data from the three sample groups also revealed a unique pattern of cross-reactivity between SARS-CoV-2 and SARS-CoV-1, MERS-CoV, and seasonal coronaviruses HKU1 and OC43. Our findings show that the CoV-2 IgM response is highly specific while the CoV-2 IgG response is more cross-reactive across a range of human CoVs and also showed that IgM and IgG responses show distinct patterns of epitope specificity. In summary, this multiplex assay was able to distinguish samples by COVID-19 status and characterize distinct trends in terms of cross-reactivity and fine-specificity in antibody responses, underscoring its potential value in diagnostic or serosurveillance efforts.

P1006Cryo-balloon ablation in elderly; Outcome and prediction of recurrence

Background

It is well known that prevalence of atrial fibrillation correlates with age, however the data on ablation of atrial fibrillation in elderly patients is poor. Aim of this study was analysis of outcome and prediction of recurrence after cryo-balloon ablation (CBA) in elderly patients based on available data in our registry.

Methods

The history of AF was assessed at admission. Additionally, all patients received echocardiographic examination and blood test. After a single trans-septal access and PV angiography PVI was performed using a 28-mm CBA. Mapping of PV signals before, during, and after each cryo application was performed with a 3F lasso catheter. The procedural endpoint after PVI was defined as complete elimination of all fragmented signals at the PV antrum with verification of entrance and exit block. Primary endpoint was first documented recurrence of AF, atrial tachycardia or atrial flutter (&gt;30 sec.). All patients received a follow-up every 3 month within 1st year, once yearly thereafter and in case of symptoms. Seven days Holter ECG was recorded by every follow up.

Results

A total of 44 (39%) of enrolled patients were male, 48 (43%) suffered non- paroxysmal AF(nPAF), 93 (82%) had hypertension, CAD was diagnosed by 27 (24%), 28 (25%) had DM (Hb1AC &gt; 6), Stroke/TIA was observed in 11 (10%). Median Age in elderly was 76 (75-78) y, BMI 25.77 (23.51-28.69), time since 1st diagnosis 40 (6-50) month, LA area index 11.36 (9.77-13.20), TAPSE 23 (19-26), GFR 74 (66-83) mL/min, LVEF 60 (57-62). A total of 44 patients (39%) reached endpoint within follow up of 20 (12-38) months. Univariate association with outcome was found by follows parameter: Time from 1st diagnosis &gt; 3 y (HR = 3.22 (1.66-6.27), p=.001); LA area index (HR = 1.17 (1.03-1.32), p=.013); DM (HR = 1.89 (1.02-3.55), p=.042); nPAF (HR = 1.90 (1.04-3.47), p=.036). After multivariate analysis only time from 1st diagnosis &gt; 3 y, (HR= 3.17 (1.62-6.16), p=.001 and nPAF (HR = 1.84 (1.01-3.36)), p=.048 were revealed to be predictive. The area under probability score calculated for these predictors was .731 (.638-8.25), p=.001. Follows complications were observed: 2 (2%) - pericard tamponades, 4 (4%) phrenicus nerve injury. Conclusion. PVI with cryo-balloon is effective for elderly patients providing freedom of arrhythmic events in 61% of patients. Longer history of AF over 3 years since 1st diagnosis was main predictor for post ablation recurrence. In elderly patients with shorter history of AF efficiency and safety of CBA is comparable with general population.

Respiration resolved imaging with continuous stable state 2D acquisition using linear frequency SWEEP

Purpose

To investigate the potential of continuous radiofrequency (RF) shifting (SWEEP) as a technique for creating densely sampled data while maintaining a stable signal state for dynamic imaging.

Methods

We present a method where a continuous stable state of magnetization is swept smoothly across the anatomy of interest, creating an efficient approach to dense multiple 2D slice imaging. This is achieved by introducing a linear frequency offset to successive RF pulses shifting the excited slice by a fraction of the slice thickness with each successive repeat times (TR). Simulations and in vivo imaging were performed to assess how this affects the measured signal. Free breathing, respiration resolved 4D volumes in fetal/placental imaging is explored as potential application of this method.

Results

The SWEEP method maintained a stable signal state over a full acquisition reducing artifacts from unstable magnetization. Simulations demonstrated that the effects of SWEEP on slice profiles was of the same order as that produced by physiological motion observed with conventional methods. Respiration resolved 4D data acquired with this method shows reduced respiration artifacts and resilience to non‐rigid and non‐cyclic motion.

Conclusions

The SWEEP method is presented as a technique for improved acquisition efficiency of densely sampled short‐TR 2D sequences. Using conventional slice excitation the number of RF pulses required to enter a true steady state is excessively high when using short‐TR 2D acquisitions, SWEEP circumvents this limitation by creating a stable signal state that is preserved between slices.

Flexible versus rigid endoscopy for treatment of foreign body impaction in the esophagus

BACKGROUND

The use of either flexible endoscopy (FE) or rigid endoscopy (RE) for removal of ingested foreign bodies (FBs) impacted in the esophagus is still discussed controversially.

METHODS

We report a consecutive series of 139 patients with FB impaction in the esophagus. During a 6-year period, 69 men and 70 women (median age, 64 [0.7-97] years) requiring removal of an impacted FB underwent either RE (n = 63) in the Otolaryngology Department of our hospital or FE (n = 76) in the Surgical Endoscopy Unit.

RESULTS

Foreign body removal was equally effective with FE (success rate 93.4%) and RE (95.2%, p = n.s.). The cases in which foreign body removal failed (5 FE cases [6.6%] and 3 RE cases [4.8%]) were all subsequently successfully managed with "conversion" and use of the other technique. No severe complications occurred when FB removal was attempted with FE (0 of 76 cases; 0.0%), whereas RE was associated with esophageal rupture requiring immediate surgical intervention in 2 of 63 cases (3.2%; p < 0.002). Patient comfort differed significantly between the two procedures (p < 0.0001); RE was always performed under general anesthesia (100.0%), whereas only a minority of patients undergoing FE required general anesthesia (13.0%; p < 0.0001) or mild analgosedation (20.0%). The better patient comfort with FE was also reflected in a significantly lower rate of dysphagia (15%) compared to RE (48%; p < 0.0001). Rigid endoscopy was more frequently used in removal of FBs of the upper esophagus (p < 0.0001), whereas FE was the predominate approach to FBs in the lower esophagus (p < 0.0001).

CONCLUSIONS

A tailored approach to treatment of FB impaction is recommended. Because of the lower rate of severe complications, better patient comfort with a lower rate of dysphagia, and lack of requirement for general anesthesia, FE should be the "first line" approach to FBs, although RE has its place as the "second line" therapy.

Application of current knowledge to the management of bleeding events during immune tolerance induction

The development of inhibitors to factor VIII is the most serious adverse event associated with the treatment of haemophilia A, predisposing patients to uncontrollable haemorrhage, disability and premature death. Eradication of inhibitors via immune tolerance induction (ITI) is effective in the majority of patients, but may require months to years to achieve success. In the interim, the treatment and prevention of acute bleeding episodes are primary foci of care. Regrettably, there is a paucity of information regarding management of bleeding episodes in inhibitor patients undergoing tolerization. Until specific data from ongoing clinical trials are available to provide more guidance in this patient group, it is reasonable and useful to rely on the broader base of medical literature pertaining to patients not being tolerized to deduce strategies for controlling acute and perioperative bleeding episodes in inhibitor patients during ITI.

Car−Parrinello Molecular Dynamics Simulation of Liquid Formic Acid

First-principles molecular dynamics has been used to investigate the structural, vibrational, and energetic properties of formic acid, formic acid-formate anion dimers, and liquid formic acid in a periodically repeated box with 32 formic acid molecules. We found that in liquid formic acid the hydrogen-bonded clusters mainly consist of linear branching chains. From our simulation, we got good agreement with the available structural and dynamical data. We also studied the proton transfer in the cis-formic acid-formate anion dimer, and we showed that this proton transfer does not have any potential barrier. The hydrogen bonding statistics as well as the mean lifetime of the hydrogen bonds are analyzed.

Autoionization in liquid water

The dissociation of a water molecule in liquid water is the fundamental event in acid-base chemistry, determining the pH of water. Because of the short time scales and microscopic length scales involved, the dynamics of this autoionization have not been directly probed by experiment. Here, the autoionization mechanism is revealed by sampling and analyzing ab initio molecular dynamics trajectories. We identify the rare fluctuations in solvation energies that destabilize an oxygen-hydrogen bond. Through the transfer of protons along a hydrogen bond "wire," the nascent ions separate by three or more neighbors. If the hydrogen bond wire connecting the two ions is subsequently broken, a metastable charge-separated state is visited. The ions may then diffuse to large separations. If, however, the hydrogen bond wire remains unbroken, the ions recombine rapidly. Because of their concomitant large electric fields, the transient ionic species produced in this case may provide an experimentally detectable signal of the dynamics we report.

Autoionization in liquid water

The dissociation of a water molecule in liquid water is the fundamental event in acid-base chemistry, determining the pH of water. Because of the short time scales and microscopic length scales involved, the dynamics of this autoionization have not been directly probed by experiment. Here, the autoionization mechanism is revealed by sampling and analyzing ab initio molecular dynamics trajectories. We identify the rare fluctuations in solvation energies that destabilize an oxygen-hydrogen bond. Through the transfer of protons along a hydrogen bond "wire," the nascent ions separate by three or more neighbors. If the hydrogen bond wire connecting the two ions is subsequently broken, a metastable charge-separated state is visited. The ions may then diffuse to large separations. If, however, the hydrogen bond wire remains unbroken, the ions recombine rapidly. Because of their concomitant large electric fields, the transient ionic species produced in this case may provide an experimentally detectable signal of the dynamics we report.

Structural and electronic properties of Co-corrole, Co-corrin, and Co-porphyrin

A quantitative study of the structure and electronic properties of Co-corrole, Co-corrin, and Co-porphyrin, using density functional theory, is reported. The structure of each macrocycle is optimized, with no symmetry constraints, by considering different spin states. The ground-state structures and spin states (S = 1 for Co-corrole, S = 0 for Co-corrin and S = 1/2 for Co-porphyrin) are in good agreement with the experimental data available. The trends in the sizes of the coordination cavities upon varying the inner metal atom and/or the macrocycle are analyzed and compared with those for the Fe-porphyrin we studied previously. Our results reveal that most of the distortion of the Co-corrin core in the B12 coenzyme is due to the inherent properties of Co-corrin. Quite different behaviors are found between corrinoids and porphyrins upon varying the spin state. While an increase in the metal-nitrogen (M-N) distance with spin state occurs in the porphyrins, the corrinoids show little variation in the M-N distance and, in some cases, undergo small structural changes in the ring structure. These results aid in understanding the often discussed question of why nature has chosen corrin/porphyrin for carrying out the particular biological functions identified in the B12 coenzyme.

Cognitive consequences and central nervous system injury following treatment for childhood leukemia

OBJECTIVES

To determine the relationship between membrane damage and intellectual and academic abilities in children with acute lymphoblastic leukemia (ALL) and pilot test a math intervention for children with ALL who were affected.

DATA SOURCES

Research studies and review articles.

CONCLUSIONS

Despite the prophylactic central nervous system (CNS) treatment for long-term disease-free survival, many children with ALL subsequently experience declines in intellectual and academic skills.

IMPLICATIONS FOR NURSING PRACTICE

Improving academic abilities in children who have received CNS treatment is of high priority and may have longlasting implications on quality of life.

[Acute normovolemic hemodilutin (ANH). Effects of ANH on the diastolic function of the left ventricle]

Ischemia-induced changes of diastolic leftventricular (LV) properties commonly precede corresponding ECG-changes. In the present experimental study the consequences of acute normovolemic hemodilution (ANH) induced dilutional anemia (hematocrit, hct 20%) for LV diastolic function were investigated. A total of 22 anaesthetized, splenectomized beagle dogs breathing room air were hemodiluted with isooncotic hydroxyethylstarch solution (6% HAES 200,000/0.5) until a hct value of 20% was reached. Before and after ANH intravascular blood volume (indocyaningreen dilution technique), global and regional myocardial blood flow (radioactive microspheres technique) and the following parameters reflecting LV diastolic properties were ascertained: 1) the maximum rate of LV pressure decrease (LVdp/dtmin), 2) slope and intercept of the enddiastolic pressure-volume relationship (EDPVR, conductance technique) and 3) the time-constant of isovolumic LV pressure decline "tau". After ANH to hct 20% diastolic LV function was found unchanged. Particularly the load-independent parameters (EDPVR-slope and tau) remained constant. The decrease of LV dp/dtmin (-2724 +/- 479 vs. -2388 +/- 408 mmHg.sek-1; p < 0.05) reflects ANH induced changes of LV pre- and afterload. Signs of subendocardial perfusion mismatch were not encountered. Presumed that the coronary vascular system is intact ANH to hct 20% does not provoque changes of LV diastolic function. Moreover neither myocardial perfusion and oxygenation nor myocardial function are endangered by this degree of dilutional anemia.

Chronic sequels after thoracoscopic procedures for benign diseases

OBJECTIVE

Chronic pains after lateral thoracotomy are present in up to 40% of cases. Chronic sequels after thoracoscopy are less common, but nevertheless, a cause for complaints by patients. Pain often reflects a recurrence of malign disease. For this reason, we only investigated patients with benign disease.

METHODS

We retrospectively investigated the incidence of chronic sequels in a consecutive series of 161 patients who underwent thoracoscopy for benign disease and were not converted to an open procedure. The data from all 144 patients, contactable at the time of investigation, who were at least 2 months postsurgery, were analyzed.

RESULTS

Chronic sequels were present in an overall of 31.4% of patients. Patients complained of chronic pain (20.1%), numbness distal to the incision sites (16.9%) and disaesthesia (8.3%). Painkillers are taken on a regular basis by 82.8% of patients with chronic pain. The use of Staplers, as well as the number of drains (1 vs. 2) used, were statistically significant (P>0.05) for chronic sequels. All other investigated factors, such as sex, age, and length of drainage, were not significantly different in the two groups.

CONCLUSION

The thoracoscopic approach is not likely to impact on the prevalence of long-term postthoracotomy sequels, and therefore, further strengths are necessary to reduce this number.

Peptostreptococcus micros smooth and rough genotypes in periodontitis and gingivitis

BACKGROUND

Two genotypes can be distinguished within the species Peptostreptococcus micros: a smooth (Sm) and a rough (Rg) type. To date no systematic study has been performed on the prevalence and proportion of both types in untreated periodontitis patients and subjects without destructive periodontal disease. Therefore, the present study was performed to investigate: 1) the relative importance of the Sm and the Rg genotype of P micros in periodontitis and gingivitis; 2) the correlation between smoking and the 2 genotypes of P micros; and 3) the systemic antibody response against the 2 genotypes in relation to the periodontal condition and smoking.

METHODS

A total of 104 untreated periodontitis patients and 41 individuals with gingivitis underwent clinical examination and microbiological sampling. Pocket samples were cultured anaerobically on blood agar plates to determine the prevalence and proportion of the Sm and Rg types of P micros. Serum antibody titers against both types of P micros were determined in all subjects by enzyme-linked immunosorbent assay (ELISA) using whole bacterial cells as antigen. Additionally, in a representative group of subjects, the antigen specificity of the serum antibodies was assessed by immunoblotting experiments.

RESULTS

The prevalence of the Sm genotype was higher in subjects with periodontitis (94%) compared to subjects with gingivitis (59%), whereas the prevalence of the Rg type was not significantly different (38% versus 29%). Similar analyses were performed for subgroups of smokers and non-smokers; within the periodontitis group, the prevalence of the Sm type was not different between smokers and non-smokers (96% and 92%, respectively), whereas the prevalence of the Rg type was higher in smokers (48%) compared to non-smokers (19%). No difference in prevalence of both types was observed between smokers and non-smokers within the gingivitis group. The titers and specificity of P micros-specific immunoglobulins in periodontitis patients were not different from those in gingivitis subjects, nor were they related to smoking status or culture-positivity.

CONCLUSIONS

The results of this study suggest that both the Sm and the Rg genotypes of P micros are part of the normal oral microbiota. However, the elevated prevalence of the Sm genotype in periodontitis and the elevated prevalence of the Rg type in periodontitis patients who smoke implies that both types can behave as opportunistic pathogens in destructive periodontal disease.

Diffuse type gastric and lobular breast carcinoma in a familial gastric cancer patient with an E-cadherin germline mutation

E-Cadherin alterations have been reported frequently in sporadic diffuse type gastric and lobular breast carcinomas. Germline mutations of this gene have been identified recently in several gastric cancer families. We analyzed seven patients with a family history of the disease who had diffuse type gastric cancer diagnosed before the age of 45 for germline mutations in CDH1, the gene encoding the E-cadherin protein. We identified a frameshift mutation in exon 3 in one patient with a strong family history of gastric cancer. The same germline mutation was found in the patient's mother, who had metachronous development of lobular breast and diffuse type gastric carcinomas. Immunohistochemistry for E-cadherin protein expression revealed an abnormal staining pattern in both of these tumors, suggesting complete inactivation of the cell adhesion molecule. Thus, our finding suggests that besides diffuse type gastric cancer, lobular breast carcinomas may be associated with germline CDH1 mutations.

Effect of acute normovolemic hemodilution on distribution of blood flow and tissue oxygenation in dog skeletal muscle

Acute normovolemic hemodilution (ANH) is efficient in reducing allogenic blood transfusion needs during elective surgery. Tissue oxygenation is maintained by increased cardiac output and oxygen extraction and, presumably, a more homogeneous tissue perfusion. The aim of this study was to investigate blood flow distribution and oxygenation of skeletal muscle. ANH from hematocrit of 36 +/- 3 to 20 +/- 1% was performed in 22 splenectomized, anesthetized beagles (17 analyzed) ventilated with room air. Normovolemia was confirmed by measurement of blood volume. Distribution of perfusion within skeletal muscle was determined by using radioactive microspheres. Tissue oxygen partial pressure was assessed with a polarographic platinum surface electrode. Cardiac index (3.69 +/- 0.79 vs. 4.79 +/- 0.73 l. min-1. m-2) and muscle perfusion (4.07 +/- 0.44 vs. 5.18 +/- 0.36 ml. 100 g-1. min-1) were increased at hematocrit of 20%. Oxygen delivery to skeletal muscle was reduced to 74% of baseline values (0.64 +/- 0.06 vs. 0.48 +/- 0.03 ml O2. 100 g-1. min-1). Nevertheless, tissue PO2 was preserved (27.4 +/- 1.3 vs. 29.9 +/- 1. 4 Torr). Heterogeneity of muscle perfusion (relative dispersion) was reduced after ANH (20.0 +/- 2.2 vs. 13.9 +/- 1.5%). We conclude that a more homogeneous distribution of perfusion is one mechanism for the preservation of tissue oxygenation after moderate ANH, despite reduced oxygen delivery.

Subxiphoidal videomediastinoscopy for diagnostic access to the anterior mediastinum

Access to the anterior mediastinum from the epigastric region through the retrosternal space, performed with a videomediastinoscope, is described. The method can be used to release the lower lobes of the thymus in transcervical thymectomy as well as for the diagnosis of retrosternal masses of uncertain origin on either side of the anterior mediastinum.

Normovolaemic haemodilution and hyperoxia have no effect on fractal dimension of regional myocardial perfusion in dogs

Hypervolaemic haemodilution makes myocardial perfusion more homogenous as reflected by reduced fractal dimension of regional myocardial perfusion. The clinically more commonly performed acute normovolaemic haemodilution, however, has not yet been studied in this respect. Hyperoxic ventilation with 100% oxygen is used in conjunction with haemodilution to compensate for low oxygen content by increasing physically dissolved oxygen in plasma. Since hyperoxia is known to cause disturbance in microcirculatory regulation we studied the effects of acute normovolaemic haemodilution to haematocrit (hct) 20 +/- 1% and hyperoxia on regional myocardial perfusion heterogeneity in 22 anaesthetized dogs using fractal and correlation analysis. Regional myocardial perfusion was assessed with radioactive microspheres. The results of the study were that heart rate, blood volume and arterial pressure were unchanged during haemodilution. Cardiac index was 3.6 +/- 0.7 L min-1 m-2 before and 4.6 +/- 0.7 L min-1 m-2 after haemodilution (P < 0.05). Fractal dimension (D) of regional myocardial perfusion was 1.17 +/- 0.10 at baseline. Neither haemodilution (D = 1.19 +/- 0.10) nor hyperoxia (D = 1.17 +/- 0.10) altered fractal properties of regional myocardial perfusion. Spatial correlation of blood flow to adjacent tissue samples before haemodilution was 0.58 +/- 0.15. Haemodilution and hyperoxia did not significantly influence spatial correlation (0.57 +/- 0.12 vs. 0.60 +/- 0.09; ns). We conclude that neither acute normovolaemic haemodilution nor haemodilution in combination with hyperoxic ventilation alter physiological myocardial perfusion heterogeneity.

IV perflubron emulsion versus autologous transfusion in severe normovolemic anemia: effects on left ventricular perfusion and function

Intact cardiac compensatory mechanisms are necessary to maintain adequate tissue oxygenation during acute normovolemic hemodilution (ANH). Left ventricular (LV) perfusion, oxygenation and function were analyzed in an experimental whole-body model of profound ANH (Hct 9%) and effectiveness of a perfluorocarbon-based oxygen carrier in maintaining myocardial oxygenation and function was evaluated. A total of 22 anesthetized dogs were hemodiluted to Hct 20% followed by a simulated, controlled blood-loss phase in which dogs were randomized to either: (1) 1:1 exchange of lost blood with autologous red blood cells (RBC-group), (2) 1:1 exchange with a colloid (control-group) and (3) 1:1 exchange with a colloid after a single dose of 1.8 g/kg BW perflubron i.v. (PFC-group). Myocardial oxygen delivery and consumption as well as endocardial perfusion were determined using radioactive microspheres. LV myocardial contractility (LV MC) was assessed from: (1) the relationship between maximum rate of LV pressure increase (LVdp/dtmax) and LV enddiastolic volume (LVEDV) and (2) analysis of the LV endsystolic pressure volume relationship (ESPVR). LV diastolic properties were reflected by (1) minimum rate of LV pressure increase (LVdp/dtmin), (2) slope and intercept of the enddiastolic pressure-volume relationship (EDPVR) and (3) the time-constant of isovolumic LV pressure decline "tau 1/2". Full sets of LV MC data were obtained from 18 dogs (n = 6 per group). LV MC (LVdp/dtmax-LVEDV relation) increased after perflubron administration. At the lowest Hct level, all parameters reflecting LV MC as well as LVdp/dtmin were significantly higher in the PFC-group than in the control-group. After profound normovolemic hemodilution (Hct 9%) superiority of LV MC and LV diastolic properties was found, when myocardial oxygenation was supported by i.v. perflubron emulsion, a temporary O2 carrier.

Hemodilution and hyperoxia locally change distribution of regional pulmonary perfusion in dogs

In seven anesthetized dogs, the effects of acute normovolemic hemodilution (ANH) to a hematocrit of 20 and 8% and the effects of hyperoxic ventilation (100% oxygen) on distribution of regional pulmonary blood flow (rPBF; radioactive microspheres) were investigated. Normovolemia was monitored with blood volume measurements (indocyanine green dilution kinetics). Before ANH, fractal dimension (D) of rPBF in the whole lung was 1.19 +/- 0.09 (mean +/- SD). Spatial correlation (rho) of rPBF in the whole lung was 0.6 +/- 0.08. D is a resolution-independent measure for global rPBF distribution, and rho is the averaged flow relationship of directly neighboring lung samples. With regard to the entire lung, neither ANH nor hyperoxia changed D or rho. With regard to horizontal, isogravitational planes, ANH induced opposite changes of rPBF heterogeneity depending on the vertical location of the plane and the parameter used. In ventral planes, a change in relative dispersion (SD/mean) indicated decreased homogeneity. However, rho suggested more homogeneous perfusion. Hyperoxia restored baseline rPBF distribution. Our data suggest that ANH causes different alterations of heterogeneity of rPBF depending on location within the lung.

Effects of hemodilution on splanchnic perfusion and hepatorenal function. II. Renal perfusion and hepatorenal function

Hepatorenal perfusion and function were assxssed in 22 dogs undergoing acute normovolemic hemodilution (ANH) to a hematocrit (Hct) of 20% using 6% hydroxyethyl starch (200.000/0.5) as the diluent. Organ perfusion was determined with the radioactive microspheres method. Renal function was assessed by urinary output, creatinine clearance and fractional sodium excretion. Blood volume as well as hepatic function were derived from indocyanine green (ICG) dilution kinetics. Hepatocellular integrity was determined by serum enzymatic activity of glutamate-oxalacetate-transaminase (GOT) and glutamate-pyruvate- transaminase (GPT). ANH to Hct 20% did not change blood volume and mean aortic pressure, while heart rate was slightly elevated (p<0.05) by 5 beats per minute and cardiac output increased by 29% (p<0.05). In contrast to the liver, where arterial and portal venous blood flow increased (86% and 28%, respectively; p<0.05), total renal blood flow as well as intraorgan distribution of renal blood flow remained unchanged post-ANH. While creatinine clearance remained unchanged following ANH, urinary output and fractional urinary excretion increased (p<0.05). In response to enhanced hepatic blood flow after ANH, intravascular half-life of ICG was reduced (p<0.05) and ICG clearance increased (p<0.05). Serum enzymatic activity of GPT decreased upon ANH (p<0.05), while GOT activity remained unchanged. ANH to a Hct 20% does not impair hepatorenal function. Increased urinary output points out the necessity for proper adjustment of crystalloid infusion to maintain normal intravascular volume and avoid hypovolemia and the associated risk of tissue hypoxia.

Effects of hemodilution on splanchnic perfusion and hepatorenal function. I. Splanchnic perfusion

Perfusion of intestinal organs increases in response to acute normovolemic hemodilution (ANH). However, detailed studies on distribution of regional splanchnic organ perfusion during ANH are lacking. We therefore carried out this study to test the hypothesis that ANH does not cause disturbance of physiologic patterns of regional splanchnic organ blood flow. After governmental permission, 22 anesthetized dogs were instrumented to allow invasive hemodynamic measurements and intracardial injection of radioactive microspheres (diameter 15 micro m) for determination of regional organ perfusion. Measurements were made at baseline (hematocrit 37 +/- 3%) and after ANH with 6% hydroxyethyl starch (mol. wt. 200000 / 0.5) to hct 20 +/- 1%. After completion of the protocol, splanchnic organs were removed and dissected into small samples according to anatomical and functional principles. Regional perfusion was determined based on the microsphere content of each sample. Hepatic, intestinal, and pancreatic blood flow increased with ANH. Hepatic arterial blood flow rose by 86%, whereas portal venous perfusion increased by 28%. Small intestine mucosal perfusion was augmented by 68% while the non-mucosal tissue compartment of the gut wall received 32% more blood flow after ANH which is in proportion to the increase in cardiac index after ANH. This redistribution of intestinal flow might be the basis for the preservation of tissue oxygenation during moderate isovolemic anemia.

Delayed diagnosis of malignant tumors missed at laparoscopic cholecystectomy

BACKGROUND

The aim of this study was to compare the significance of routine examinations prior to laparoscopic cholecystectomy (LC) with intraoperative abdominal investigation. Preoperative evaluation becomes increasingly important when laparoscopic procedures are performed for the removal of gallstones because other intraabdominal diseases may coexist in these patients, mimicking biliary tract disease.

METHODS

Over the last 6 years, we treated 816 patients with symptomatic cholecystolithiasis using LC. Prior to surgery, routine tests such as upper abdominal ultrasonography, chest radiography, and standard laboratory blood tests were carried out.

RESULTS

Despite these routine tests, coexisting colonic cancers escaped detection in four out of 816 cases. This indicates a risk of more "missed pathologies" during the course of laparoscopic operations compared to standard laparotomy.

CONCLUSION

The risk of missing coexisting diseases during laparoscopic operations has to be minimized by placing additional emphasis on careful evaluation of anamnesis. Physical examination and additional laboratory tests--such as analysis of tumor markers and blood in the stool--combined with complete abdominal ultrasonography, gastroscopy, and/or complete colonoscopy should be performed prior to LC.

Effects of hemodilution on gastric regional perfusion and intramucosal pH

Acute normovolemic hemodilution (ANH) has been shown to be a cost-effective method of reducing allogenic blood transfusion during elective surgery. ANH has been implicated with impaired oxygenation in isolated canine gastric flaps. The present study was designed to investigate the effects of ANH on gastric mucosal oxygenation using a model closely imitating the clinical situation. Sixteen splenectomized anesthetized beagles were isovolemically hemodiluted to a hematocrit of 20 +/- 1% (6% hydroxyethyl starch; mol wt 200,000; substitution ratio 0.45-0.55). Blood volume (indocyanine green), cardiorespiratory parameters, gastric intramucosal pH (pHi), and gastric regional blood flow (radioactive microspheres; 15 microns) were measured before and after ANH.

RESULTS

blood volume was unchanged (87 +/- 8 ml/kg before and 88 +/- 7 ml/kg after ANH). Median total gastric mucosal blood flow at baseline was 0.51 +/- 0.35 ml.min-1.g-1 and did not change significantly upon ANH. The mean pHi was 7.29 +/- 0.05 before and 7.28 +/- 0.05 after hemodilution. There was a homogenization of blood flow distribution in gastric mucosa. Severe hemodilution to a hematocrit of 20% does not impair gastric mucosal oxygenation and poses no risk to gastric mucosal integrity.