Comparison of complement fixation and hemagglutination inhibition assays for detecting antibody responses following influenza virus vaccination

Complement fixation (CF) was compared to hemagglutination inhibition (HI) as a method for identifying antibody responses to influenza virus vaccination. CF assays were performed at two different laboratories using paired (pre- and postvaccination) sera from 38 vaccinated laboratory employees; HI assays were performed at a third laboratory. As expected, most vaccinees (31/38 = 82%) responded to at least one of three influenza virus antigens as measured by HI. In contrast, only 21% (8/38) of vaccinees showed a response by CF at laboratory 1, and only 29% (11/38) showed a response by CF at laboratory 2. These findings indicate that due to low sensitivity, CF assays should not be used to assess the antibody response to influenza virus vaccination.     

Noradrenergic modulation of firing pattern in guinea pig and cat thalamic neurons, in vitro

1. The electrophysiological actions of norepinephrine (NE) in the guinea pig and cat thalamus were investigated using intracellular recordings from neurons of in vitro thalamic slices. 2. Application of NE to neurons of the lateral and medial geniculate nuclei, nucleus reticularis, anteroventral nucleus, and the parataenial (PT) nucleus resulted in a slow depolarization associated with a 2- to 15-nS decrease in input conductance and an increase in the slow membrane time constant from an average of 27.7 to 37.7 ms. The slow depolarization was not abolished by blockade of synaptic transmission, indicating that it was a direct (postsynaptic) effect. 3. The reversal potential of the NE-induced slow depolarization varied as a Nernstian function of extracellular potassium concentration ([K]o), indicating that it is due to a decrease in potassium conductance. This conclusion was supported by the finding that the amplitude of the NE-evoked depolarization was affected by changes in [K]o between 0.5 and 5.0 mM as expected for a K-mediated response. 4. Neurons of the PT nucleus displayed unusually large afterhyperpolarizations (AHPs) in comparison to cells in other thalamic nuclei. NE application to PT neurons caused not only a marked slow depolarization and decreased conductance, but also selectively reduced the slow AHP. 5. The NE-induced slow depolarization effectively suppressed burst firing and promoted the occurrence of single spike activity. NE-induced reduction of the slow AHP in PT neurons was accompanied by a decrease in spike frequency accommodation and the emergence of a slow afterdepolarization. 6. We suggest that through these electrophysiological actions, NE can effectively inhibit the generation of thalamocortical rhythms and greatly facilitate the faithful transfer of information through the thalamus to the cerebral cortex.     

Outward chloride/cation co-transport in mammalian cortical neurons

The mechanism underlying outward chloride transport in guinea pig cingulate cortical neurons of in vitro slices was characterized with respect to its pharmacological antagonists and anion selectivity, and the nature of other ion movements coupled to Cl- transport. Changes in intracellular Cl- concentration, following iontophoresis of Cl- from KCl-filled intracellular recording electrodes, were estimated from changes in the amplitude of GABAergic, Cl(-)-mediated inhibitory postsynaptic potentials (IPSPs). The rate of outward Cl- transport was found to be reduced by bumetanide but not by SITS. SCN-, but not NO3-, was found to be actively transported. Increasing the extracellular K+ concentration ([K+]o) from 2.5 to 10 mM was found to inhibit Cl- extrusion. These data suggest that active Cl- extrusion from mammalian cortical neurons is mediated by an outwardly directed chloride/cation cotransport mechanism. Inhibition of this process by elevated [K+]o may be important in epilepsy.     

Determinants of attrition in a pediatric healthy lifestyle intervention: The CIRCUIT program experience

IntroductionAttrition in pediatric weight management programs is notoriously high. Greater understanding of its determinants is needed to inform retention strategies. We identified determinants of attrition in CIRCUIT, a healthy lifestyle intervention program for youth at risk of cardiovascular disease.MethodsA one-arm intervention study of children aged 4-18 years who initiated the CIRCUIT program in the first five years of its existence (N = 403). We defined attrition as attending the baseline visit but ceasing attendance prior to the 1-year follow-up. Potential determinants of dropout included the child’s age, sex, ethnicity, body mass index (BMI) z-score, family socio-demographic characteristics, and estimated driving time to the program, all measured at baseline. Associations were estimated bivariately, using chi-squared- and t-tests, and simultaneously in a multivariable logistic regression model.ResultsOf the 403 participants who started the program, 198 (49%) dropped out within 12 months of enrollment. Youth who dropped out were older (mean age 12.8y vs. 11.3y; p < 0.01), were less likely to live with both parents (62% vs. 71%; p = 0.05), and to have mothers who had completed high school (79% vs. 88%; p = 0.01). No group differences were observed for sex, ethnicity, baseline BMI z-score, fathers’ education, or driving time to the program. In multivariate models, only older age at initiation of the intervention (OR: 1.2; CI: 1.1,1.3) and lower maternal education (OR: 2.0; CI: 1.0,3.8) were associated with dropout.ConclusionImproved tailoring of interventions to older pediatric participants and to families of lower maternal education may help reduce attrition in CIRCUIT and similar lifestyle intervention programs.     

Macroscopic hematuria in wasp sting patients: a retrospective study

BackgroundMacroscopic hematuria after wasp sting has been reported in Asia to occur before acute kidney injury (AKI), and is often used by clinicians as a sign indicating the need for intensive care and blood purification therapy. However, there is no study on the clinical characteristics and prognosis of this symptom.MethodsThe clinical data of 363 patients with wasp sting admitted to Suining Central Hospital from January 2016 to December 2018 were retrospectively analyzed. At admission, the poisoning severity score (PSS) was used as the criterion for severity classification. According to the presence of macroscopic hematuria, the patients were divided into macroscopic hematuria and non-macroscopic hematuria group.ResultsOf the 363 wasp sting patients, 219 were male and 144 were female, with a mean age of 55.9 ± 16.3 years. Fifty-one (14%) had macroscopic hematuria, 39 (10.7%) had AKI, 105 (28.9%) had rhabdomyolysis, 61 (16.8%) had hemolysis, 45 (12.4%) went on to received hemodialysis, and 14 (3.9%) died. The incidence of AKI in macroscopic hematuria group was 70.6%, and oliguric renal failure accounted for 72.2%. Patients with macroscopic hematuria had significantly higher PSS (2.2 ± 0.5 vs. 1.1 ± 0.3, p < .001).ConclusionMacroscopic hematuria can be regarded as a surrogate marker of deteriorating clinical outcome following wasp stings. In wasp sting patients with symptoms of macroscopic hematuria or serum LDH higher than 463.5 u/L upon admission, the risk of AKI increases significantly, therefore hemodialysis should be considered. The PSS is helpful in early assessment of the severity of wasp sting patients.     

Higher Undercarboxylated to Total Osteocalcin Ratio Is Associated With Reduced Physical Function and Increased 15-Year Falls-Related Hospitalizations: The Perth Longitudinal Study of Aging Women

Evidence from animal models suggests that undercarboxylated osteocalcin (ucOC) is involved in muscle mass maintenance and strength. In humans, the ucOC to total (t)OC ratio may be related to muscle strength and perhaps physical function and falls risk, but data are limited. We tested the hypothesis that ucOC and ucOC/tOC ratio are associated with muscle function (muscle strength and physical function) in older women and 15-year falls-related hospitalizations. Serum tOC and ucOC were assessed in 1261 older women (mean age 75.2 ± 2.7 years) forming the Perth Longitudinal Study of Aging Women (1998 to 2013). Timed-up-and-go (TUG) and grip strength were assessed at baseline and at 5 years. Falls-related hospitalizations (14.5-year follow-up) were captured by the Hospital Morbidity Data Collection, via the Western Australian Data Linkage System. At baseline, women with higher ucOC/tOC ratio (quartile 4) had slower TUG performance compared with quartile 1 (~0.68 seconds, p < .01). Grip strength and 5-year change of TUG and grip were not different (p > .05) between quartiles. Fear of falling limiting house, outdoor, and combined activities was significantly different across quartiles (p < .05). Higher ucOC/tOC was significantly associated with poorer TUG performance at baseline and 5-year change in performance, increased walking aid use, and fear of falling (all p < .05). Higher ucOC was related to lower grip strength at baseline (p < .05) but not 5-year change in strength. Those with the highest ucOC/tOC had greater falls-related hospitalizations (unadjusted log rank, p = .004) remaining significant after adjusting for key variables (hazard ratio [HR] = 1.31, 95% confidence interval [CI] 1.09–1.57, p = .004). We identified a large proportion of older women with high ucOC/tOC ratio who had reduced physical function, including its long-term decline and increased risk of falls-related hospitalizations. Early identification of women at higher risk can enable prevention and intervention strategies to occur, reducing risk for injurious falls. © 2020 American Society for Bone and Mineral Research (ASBMR)..     

Experimental microgyri disrupt the barrel field pattern in rat somatosensory cortex

Transcranial freeze lesions in neonatal rat pups produce microgyri and adjacent epileptogenic regions of neocortex that can be used to model human polymicrogyria. The hypothesis that the presence of microgyri is associated with abnormal cortical organization occurring within as well as adjacent to the microgyri was tested by creating microgyri within the face representation of somatosensory cortex. Microgyri were associated with a widespread disruption of the stereotypic whisker barrel field pattern delineated with cytochrome oxidase (CO) staining. CO-stained patches resembling barrel hollows were absent within the microgyrus, and were abnormally shaped and distributed outside of the microgyrus. Adjacent Nissl- or acetylcholinesterase-stained sections demonstrated that both cell clusters and thalamocortical afferents contributed to the abnormally organized paramicrogyral zone identified in CO-stained sections. Field potential recordings showed that this region of heavy CO staining corresponded to the epileptogenic zone adjacent to the microgyrus. Results support our hypothesis that the epileptogenic paramicrogyral zone develops an abnormal organization of cell clusters and thalamocortical projections that could contribute to epileptogenesis in the paramicrogyral zone.