Effects of off-pump coronary surgery on the mechanics of the respiratory system,lung, and chest wall: Comparison with extracorporeal circulation

OBJECTIVE: To compare the effects of cardiac surgery with and without extracorporeal circulation on the mechanics of the respiratory system, lung, and chest wall. We also determined the time course of those effects. DESIGN: Prospective, controlled study. SETTING: An eight-bed, cardiac-surgical intensive care unit at a university hospital. PATIENTS: Two groups of patients scheduled for elective coronary bypass surgery were studied: ten patients with extracorporeal circulation and 13 patients without extracorporeal circulation. INTERVENTIONS: Measurement of esophageal pressure after insertion of an esophageal balloon catheter to separate respiratory system mechanics into lung and chest wall components. Measurements were performed preoperatively after induction of anesthesia (control), immediately postoperatively at arrival in the intensive care unit (time 1), and after 3 hrs (time 2). In 12 of the 23 patients, measurements were also performed 6 hrs postoperatively (time 3). MEASUREMENTS AND MAIN RESULTS: No significant differences concerning demographics or surgical procedure were noticed between the two groups. Respiratory system, chest wall, and lung mechanics were obtained using the technique of rapid airway occlusion during constant-flow inflation. In both the group with and without extracorporeal circulation there was a significant increase in static and dynamic elastance of the respiratory system and lung at times 1 and 2, which tended to decrease again at time 3; chest wall elastance significantly increased at times 2 and 3 in the group without extracorporeal circulation, whereas the increase in chest wall elastance in the group with extracorporeal circulation occurred earlier (also at time 1). Additional resistance of the respiratory system and lung remained unchanged; chest wall resistance, however, significantly increased in both groups. Work of breathing significantly increased in both groups at times 1 and 2. There was a significant reduction in the Pao2/Fio2 ratio in both groups at times 2 and 3. No significant differences between the groups at any moment were noticed. CONCLUSIONS: Coronary bypass surgery with and without extracorporeal circulation results in dramatic impairment of respiratory system mechanics. Based on respiratory system mechanics, early extubation after coronary artery bypass grafting should be performed with caution, no matter whether the off-pump or cardiopulmonary bypass technique is used.     

Risky sexual behavior among patients on long-term antiretroviral therapy: a prospective cohort study in urban and rural Uganda

Background

While the effects of initiation of antiretroviral treatment (ART) on risky sexual behavior have been extensively studied, less is known about the long-term changes in risky sexual behavior over time in resource-poor settings.

Methods

We conducted a secondary longitudinal analysis of one rural and one urban cohort of patients who initiated ART in Uganda between April 2004 and July 2007 followed up-to 2016. Data on sexual behavior were collected every 6 months for 3.5 years in individuals on ART?≥?4 years (baseline) when a behavioral questionnaire was introduced. Risky sexual behavior was defined as sexual intercourse with?≥?2 partners or inconsistent or no condom use in previous 6 months. We report characteristics overall, and by cohort. We used multivariable generalized estimating equations logistic regression to assess the effects of time on ART on risky sexual behavior.

Results

Of 1012 participants, 402 (39.8%) were urban and 610 (60.2%) were rural residents. Mean age was 42.8 years (SD 8.5). Mean duration of follow-up was 51.3 months (SD 15.3), but longer for urban than rural participants (64.5 vs 36.4 months). Risky sexual behavior declined from 33.1% at baseline to 9.6% after 3.5 years of follow-up in the rural cohort (p?≤?0.01 for the test of trend) and was unchanged from 9.7% at baseline to 9.9% after 3.5 years in the urban cohort (p?=?0.51). Receiving care at a rural clinic (aOR 4.99, 95% CI 3.64–6.84); male gender (aOR 1.66, 95% CI 1.26–2.19) and being younger (aOR 5.60, 95% CI 3.80–8.25 for 18–34 years and aOR 2.34, 95% CI 1.74–3.14 for 35–44 years) were associated with increased odds of risky sexual behavior. Not being married (aOR 0.25; 95% CI 0.19–0.34), and longer time on ART (aOR 0.71 95% CI 0.67–0.76) were associated with reduced odds of risky sex.

Conclusions

We observed a decline in risky sexual behavior in rural people on long-term (≥?4 years) ART. Rural, male and young individuals had higher odds of self-reported risky sexual behavior. ART programs should continue to emphasize risk reduction practices, especially among people receiving care in rural health facilities, males, younger individuals and those who are married.

     

Astrocytes derived from fetal neural progenitor cells as a novel source for therapeutic adenosine delivery

PurposeIntracerebral delivery of anti-epileptic compounds represents a novel strategy for the treatment of refractory epilepsy. Adenosine is a possible candidate for local delivery based on its proven anti-epileptic effects. Neural stem cells constitute an ideal cell source for intracerebral transplantation and long-term drug delivery. In order to develop a cell-based system for the long-term delivery of adenosine, we isolated neural progenitor cells from adenosine kinase deficient mice (Adk^?/?) and compared their differentiation potential and adenosine release properties with corresponding wild-type cells.MethodsFetal neural progenitor cells were isolated from the brains of Adk^?/? and C57BL/6 mice fetuses and expanded in vitro. Before and after neural differentiation, supernatants were collected and assayed for adenosine release using liquid chromatography–tandem mass spectrometry (LC–MS/MS).ResultsAdk^?/? cells secreted significantly more adenosine compared to wild-type cells at any time point of differentiation. Undifferentiated Adk^?/? cells secreted 137 ± 5 ng adenosine per 10⁵ cells during 24 h in culture, compared to 11 ± 1 ng released from corresponding wild-type cells. Adenosine release was maintained after differentiation as differentiated Adk^?/? cells continued to release significantly more adenosine per 24 h (47 ± 1 ng per 10⁵ cells) compared to wild-type cells (3 ± 0.2 ng per 10⁵ cells).ConclusionsFetal neural progenitor cells isolated from Adk^?/? mice – but not those from C57BL/6 mice – release amounts of adenosine considered to be of therapeutic relevance.     

Behavioral pattern analysis and dopamine release in quinpirole-induced repetitive behavior in rats

Obsessive-compulsive disorder (OCD) is a chronic and disabling psychiatric disease with a lifetime prevalence of 2-3%. People with OCD suffer from intrusive, unwanted and recurrent thoughts (obsessions) and/or repetitive ritualistic behaviors (compulsions). The aim of this study is to quantify the dimensions of ritualistic 'compulsive-like' behavior in quinpirole-induced behavior in rats by using T-pattern behavioral analysis. In addition, we investigated whether the behavioral effects elicited by quinpirole sensitization remained after 2 weeks of cessation of treatment. Finally, to study the neurobiological underpinnings of this 'compulsive-like' behavior, we investigated the effect of quinpirole treatment on the extracellular dopamine levels in the nucleus accumbens. Once established, 'compulsive-like' behavior is dependent upon quinpirole administration, as this behavior rapidly normalized after cessation of treatment. After a single dose of quinpirole the dopamine level decreased more in saline pre-treated animals as compared with animals given quinpirole treatment continuously. Furthermore, T-pattern analysis revealed that quinpirole-induced behavior consists, unlike OCD rituals, of a smaller behavioral repertoire. As seen in patients with OCD, quinpirole-treated animals performed these behaviors with a high rate of repetition. These findings suggest that quinpirole-induced behavior mimics only part of the compulsive behavior as shown in OCD patients.