Validation of Respiratory Inductance Plethysmography for Measuring Tidal Volume in Swine

Measuring tidal volume (V_T) in nonintubated swine or swine with leaking breathing circuits is challenging. The aim of this study was to validate respiratory inductance plethysmography (RIP) for measuring V_T in swine that are comparable in size to adult humans. To determine calibration curves, V_T and RIP readings were obtained from anesthetized swine (n = 8; weight, 46–50 kg) during positive-pressure (mechanical) ventilation and spontaneous breathing. For positive-pressure ventilation, 6 pigs were mechanically ventilated by using the pressure-control mode. The 2 pigs in the spontaneously breathing cohort each received a single intravenous bolus dose of propofol to abolish spontaneous breathing; V_T was measured during gradual return of their respiratory drive. A flow–volume sensor was placed between the proximal end of the endotracheal tube and breathing circuit for the recording of inspiratory and expiratory V_T. RIP readings were recorded by using 2 bands, which simultaneously measured ribcage and abdominal excursions. The data revealed that V_T was linearly correlated with the movements of both ribcage and abdomen as measured by using plethysmography over a large range of tidal volume (44 to 1065 mL). In addition, the intercept of the linear equation was small or even negative during spontaneous breathing but increased significantly (maximum, 145 mL, 59.2 ± 35.1 mL) during positive pressure ventilation. Our results indicate that V_T in swine can be calculated by using a simple univariate linear regression equation with RIP readings obtained during either mechanical ventilation or spontaneous breathing.Abbreviations: RIP, respiratory inductance plethysmography; V_T, tidal volumeIn animal care and research, the respiratory function of swine is widely assessed by measuring tidal volume (V_T).⁶ Although V_T is easy to measure in intubated pigs, it is difficult to measure in swine that are either nonintubated or have significant breathing circuit leakage^16,24. Using facemasks attached to minimally restrained swine is currently the method of choice for measuring V_T. This methodology has multiple limitations, including incomplete sealing between the pig''s face and the mask, which is difficult to adapt to these animals. A reliable, minimally invasive method for determining V_T in this species is needed.Respiratory inductance plethysmography (RIP)^11,15 is a viable alternative to measuring V_T. Using RIP, both ribcage and abdominal movements can be recorded. The amplitude changes of the ribcage and abdomen are linearly correlated to the size of the corresponding V_T in humans. This method has been validated in humans^1,13 and is widely used clinically in adults,^14,18 newborns and infants.^5,8 RIP has also been used on animals including sheep⁴ and dogs.¹⁷However, RIP has not yet been validated for use in swine that are comparable in size to adult humans. Considering the profound physiologic and anatomic differences in the respiratory system between swine and humans,^12,20 the validation of plethysmography for use in humans might not extrapolate readily to swine, which are one of the most commonly used animal models in biomedical research. Here we sought to validate the RIP method for calculating V_T in swine during both positive-pressure ventilation and spontaneous breathing.     

A Short Scale for Measuring Loneliness in Large Surveys: Results From Two Population-Based Studies

Most studies of social relationships in later life focus on the amount of social contact, not on individuals' perceptions of social isolation. However, loneliness is likely to be an important aspect of aging. A major limiting factor in studying loneliness has been the lack of a measure suitable for large-scale social surveys. This article describes a short loneliness scale developed specifically for use on a telephone survey. The scale has three items and a simplified set of response categories but appears to measure overall loneliness quite well. The authors also document the relationship between loneliness and several commonly used measures of objective social isolation. As expected, they find that objective and subjective isolation are related. However, the relationship is relatively modest, indicating that the quantitative and qualitative aspects of social relationships are distinct. This result suggests the importance of studying both dimensions of social relationships in the aging process.     

The African Swine Fever Virus Thymidine Kinase Gene Is Required for Efficient Replication in Swine Macrophages and for Virulence in Swine

African swine fever virus (ASFV) replicates in the cytoplasm of infected cells and contains genes encoding a number of enzymes needed for DNA synthesis, including a thymidine kinase (TK) gene. Recombinant TK gene deletion viruses were produced by using two highly pathogenic isolates of ASFV through homologous recombination with an ASFV p72 promoter–β-glucuronidase indicator cassette (p72GUS) flanked by ASFV sequences targeting the TK region. Attempts to isolate double-crossover TK gene deletion mutants on swine macrophages failed, suggesting a growth deficiency of TK⁻ ASFV on macrophages. Two pathogenic ASFV isolates, ASFV Malawi and ASFV Haiti, partially adapted to Vero cells, were used successfully to construct TK deletion viruses on Vero cells. The selected viruses grew well on Vero cells, but both mutants exhibited a growth defect on swine macrophages at low multiplicities of infection (MOI), yielding 0.1 to 1.0% of wild-type levels. At high MOI, the macrophage growth defect was not apparent. The Malawi TK deletion mutant showed reduced virulence for swine, producing transient fevers, lower viremia titers, and reduced mortality. In contrast, 100% mortality was observed for swine inoculated with the TK⁺ revertant virus. Swine surviving TK⁻ ASFV infection remained free of clinical signs of African swine fever following subsequent challenge with the parental pathogenic ASFV. The data indicate that the TK gene of ASFV is important for growth in swine macrophages in vitro and is a virus virulence factor in swine.     

Classical Swine Fever Virus vs. Classical Swine Fever Virus: The Superinfection Exclusion Phenomenon in Experimentally Infected Wild Boar

Two groups with three wild boars each were used: Group A (animals 1 to 3) served as the control, and Group B (animals 4 to 6) was postnatally persistently infected with the Cat01 strain of CSFV (primary virus). The animals, six weeks old and clinically healthy, were inoculated with the virulent strain Margarita (secondary virus). For exclusive detection of the Margarita strain, a specific qRT-PCR assay was designed, which proved not to have cross-reactivity with the Cat01 strain. The wild boars persistently infected with CSFV were protected from superinfection by the virulent CSFV Margarita strain, as evidenced by the absence of clinical signs and the absence of Margarita RNA detection in serum, swabs and tissue samples. Additionally, in PBMCs, a well-known target for CSFV viral replication, only the primary infecting virus RNA (Cat01 strain) could be detected, even after the isolation in ST cells, demonstrating SIE at the tissue level in vivo. Furthermore, the data analysis of the Margarita qRT-PCR, by means of calculated ΔCt values, supported that PBMCs from persistently infected animals were substantially protected from superinfection after in vitro inoculation with the Margarita virus strain, while this virus was able to infect naive PBMCs efficiently. In parallel, IFN-α values were undetectable in the sera from animals in Group B after inoculation with the CSFV Margarita strain. Furthermore, these animals were unable to elicit adaptive humoral (no E2-specific or neutralising antibodies) or cellular immune responses (in terms of IFN-γ-producing cells) after inoculation with the second virus. Finally, a sequence analysis could not detect CSFV Margarita RNA in the samples tested from Group B. Our results suggested that the SIE phenomenon might be involved in the evolution and phylogeny of the virus, as well as in CSFV control by vaccination. To the best of our knowledge, this study was one of the first showing efficient suppression of superinfection in animals, especially in the absence of IFN-α, which might be associated with the lack of innate immune mechanisms.     

Measuring Psychological Capital: Construction and Validation of the Compound PsyCap Scale (CPC-12)

With the Psychological Capital Questionnaire (PCQ) being the standard measure to assess psychological capital (PsyCap) in the context of organizations, this paper aims to broaden this domain-specific approach by introducing a measure with universal claim. Two studies were conducted to create and validate a German self-report scale (CPC-12) measuring PsyCap. We performed confirmatory factor analyses and correlations with other positive psychological constructs on the data of two German samples (N₁ = 321; N₂ = 202). The twelve-item CPC-12 exhibits the anticipated factorial structure with a very good model fit and associations to other constructs concur with previous findings with other measures of PsyCap.     

Large Scale Purification of Isoinhibitors of Trypsin from Swine Colostrum Using Zinc Chelate Chromatography and Chromatofocusing

Low molecular weight trypsin inhibitors were purified from swine colostrum on a large scale under mild conditions. Ammonium sulfate fractionation and metal chelate chromatography on zinc chelate Sepharose and phenyl Sepharose were used for removal of the bulk of proteins. The inhibitors showed only a weak hydrophobic interaction with phenyl Sepharose even in the presence of 1 M (Nll₄)₂SO4, and advantage was taken of this property to remove the inhibitors from contaminating colostrum proteins which remained tightly adsorbed to phenyl Sepharose under these conditions. The low and high molecular weight inhibitors were then separated by gel filtration on Bio-Gel P-300. The low molecular weight material was eluted in three major inhibitor fractions on DEAE-Sepharose.

Chromatofocusing of these fractions provided greater resolution of the inhibitors, and several previously unreported inhibitor peaks were detected. The six major inhibitors purified by chromatofocusing were homogeneous as judged by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. These inhibitors were composed of a single polypeptide chain with a molecular weight of 18,000 as determined by Sephacryl S-200 gel filtration and polyacrylamide qel electrophoresis in the presence of sodium dodecyl sulfate and e-mercaptoethanol. The specific activities of the pure inhibitors were approximately 30% higher than those previously reported.     

Measuring Cognitive Errors Using the Cognitive Distortions Scale (CDS): Psychometric Properties in Clinical and Non-Clinical Samples

The Cognitive Distortions Scale was developed to assess thinking errors using case examples in two domains: interpersonal and personal achievement. Although its validity and reliability has been previously demonstrated in non-clinical samples, its psychometric properties and scoring has not yet been evaluated. The aim of the current study was to evaluate the psychometric properties of the Cognitive Distortions Scale in two Turkish samples and to examine the usefulness of the categorical scoring system. A total of 325 individuals (Sample 1 and Sample 2) were enrolled in this study to assess those psychometric properties. Our Sample 1 consisted of 225 individuals working as interns at the Diskapi Yildirim Beyazit Teaching and Research Hospital and Sample 2 consisted of 100 patients diagnosed with depression presenting to the outpatient unit of the same Hospital. Construct validity was assessed using the Beck Depression Inventory, the State Trait Anxiety Inventory, the Dysfunctional Attitude Scale, and the Automatic Thought Questionnaire. Factor analyses supported a one-factor model in these clinical and non-clinical samples. Cronbach''s α values were excellent in both the non-clinical and clinical samples (0.933 and 0.918 respectively). Cognitive Distortions Scale scores showed significant correlation with relevant clinical measures. Study Cognitive Distortions Scale scores were stable over a time span of two weeks. This study showed that the Cognitive Distortions Scale is a valid and reliable measure in clinical and non-clinical populations. In addition, it shows that the categorical exists/does not exist scoring system is relevant and could be used in clinical settings.     

Measuring the Closeness of Relationships: A Comprehensive Evaluation of the 'Inclusion of the Other in the Self' Scale

Understanding the nature and influence of social relationships is of increasing interest to behavioral economists, and behavioral scientists more generally. In turn, this creates a need for tractable, and reliable, tools for measuring fundamental aspects of social relationships. We provide a comprehensive evaluation of the ''Inclusion of the Other in the Self'' (IOS) Scale, a handy pictorial tool for measuring the subjectively perceived closeness of a relationship. The tool is highly portable, very easy for subjects to understand and takes less than 1 minute to administer. Across our three online studies with a diverse adult population (n = 772) we show that six different scales designed to measure relationship closeness are all highly significantly positively correlated with the IOS Scale. We then conduct a Principal Component Analysis to construct an Index of Relationship Closeness and find that it correlates very strongly (ρ = 85) with the IOS Scale. We conclude that the IOS Scale is a psychologically meaningful and highly reliable measure of the subjective closeness of relationships.     

Swine in cardiovascular research

Swine are being chosen with increasing frequency as subjects for cardiovascular research. Similarities to humans in their cardiovascular physiology, size, anatomy, and the perfusion distribution of blood flows make them better subjects than most species. In addition, swine can be less expensive than dogs and primates and they generally are not associated with the same high concern as other species about humane issues.     

The Prevalence of Toxoplasma Antibodies in Swine Sera in Finland

A total of 1847 swine sera obtained from the 10 largest abattoirs slaughtering swine in Finland were examined by ELISA for toxoplasma antibodies. The sample represented 0.64 % of the total number of swine slaughtered in these abattoirs over a period of 2 months. The prevalence of toxoplasma antibodies in swine sera was 2.5 %.