The effect of acute and repeated ischemic preconditioning on recovery following exercise-induced muscle damage

OBJECTIVES

The aim of this investigation was to determine if acute or repeated applications of ischemic preconditioning (IPC) could enhance the recovery process, following exercise induced muscle damage (EIMD).

DESIGN

Randomized control trial.

METHODS

Twenty-three healthy males were familiarised with the muscle damaging protocol (five sets of 20 drop jumps from a 0.6 m box) and randomly allocated to one of three groups: SHAM (3 × 5 min at 20 mmHg), Acute IPC (3 × 5 min at 220 mmHg) and Repeated IPC (3 days x 3 × 5 min at 220 mmHg). The indices of muscle damage measured included creatine kinase concentration ([CK]), thigh swelling, delayed onset muscle soreness, counter movement jumps (CMJ) and maximal voluntary isometric contraction (MVIC).

RESULTS

Both acute and repeated IPC improved recovery in MVIC versus SHAM. Repeated IPC led to a faster MVIC recovery at 48 h (101.5%) relative to acute IPC (92.6%) and SHAM (84.4%) (P <  0.05). Less swelling was found for both acute and repeated IPC vs. SHAM (P <  0.05) but no group effects were found for CMJ, soreness or [CK] responses (P >  0.05).

CONCLUSION

Taken together, repeated IPC can enhance recovery time of MVIC more than an acute application, and both reduce swelling following EIMD, relative to a SHAM condition.

Multiplexed detection and quantification of human antibody response to COVID-19 infection using a plasmon enhanced biosensor platform

The 2019 SARS CoV-2 (COVID-19) pandemic has illustrated the need for rapid and accurate diagnostic tests. In this work, a multiplexed grating-coupled fluorescent plasmonics (GC-FP) biosensor platform was used to rapidly and accurately measure antibodies against COVID-19 in human blood serum and dried blood spot samples. The GC-FP platform measures antibody-antigen binding interactions for multiple targets in a single sample, and has 100% selectivity and sensitivity (n = 23) when measuring serum IgG levels against three COVID-19 antigens (spike S1, spike S1S2, and the nucleocapsid protein). The GC-FP platform yielded a quantitative, linear response for serum samples diluted to as low as 1:1600 dilution. Test results were highly correlated with two commercial COVID-19 antibody tests, including an enzyme linked immunosorbent assay (ELISA) and a Luminex-based microsphere immunoassay. To demonstrate test efficacy with other sample matrices, dried blood spot samples (n = 63) were obtained and evaluated with GC-FP, yielding 100% selectivity and 86.7% sensitivity for diagnosing prior COVID-19 infection. The test was also evaluated for detection of multiple immunoglobulin isotypes, with successful detection of IgM, IgG and IgA antibody-antigen interactions. Last, a machine learning approach was developed to accurately score patient samples for prior COVID-19 infection, using antibody binding data for all three COVID-19 antigens used in the test.

A fluorescent plasmonic biochip assay for multiplex screening of diagnostic serum antibody targets in human Lyme disease

Lyme disease (LD) diagnosis using the current two-tier algorithm is constrained by low sensitivity for early-stage infection and ambiguity in determining treatment response. We recently developed a protein microarray biochip that measures diagnostic serum antibody targets using grating-coupled fluorescent plasmonics (GC-FP) technology. This strategy requires microliters of blood serum to enable multiplexed biomarker screening on a compact surface and generates quantitative results that can be further processed for diagnostic scoring. The GC-FP biochip was used to detect serum antibodies in patients with active and convalescent LD, as well as various negative controls. We hypothesized that the quantitative, high-sensitivity attributes of the GC-FP approach permit: 1) screening of antibody targets predictive for LD status, and 2) development a diagnostic algorithm that is more sensitive, specific, and informative than the standard ELISA and Western blot assays. Notably, our findings led to a diagnostic algorithm that may be more sensitive than the current standard for detecting early LD, while maintaining 100% specificity. We further show that analysis of relative antibody levels to predict disease status, such as in acute and convalescent stages of infection, is possible with a highly sensitive and quantitative platform like GC-FP. The results from this study add to the urgent conversation regarding better diagnostic strategies and more effective treatment for patients affected by tick-borne disease.

Heritability of Health and Aging Limitations on Personally Desired Activities

The aim of this study is to estimate heritability of incident limitations on personally desired activities within the eighth decade of life. We measured self-rated ability to perform ten personally desired activities in 1606 male veteran twin pairs at baseline and four years later. At follow-up, 33% of the cohort reported more limitations in desired activities. Among twins who completed both assessments, there were no statistically significant differences in incidence rates of limitations as a function of zygosity. Sensitivity tests showed the same for change scores; and that, if cognitive impairment or death are deemed to belong among limitations of desired activities, zygosity contributed 10% to new limitations at follow-up. Maintaining personally desired activities over four years in the eighth decade is not subject to substantial genetic influence. However, if death and cognitive impairment are added to incident limitations, then genetics plays a modest role. In all cases, unique environment is the predominant influence.

Assessing the image quality of pelvic MR images acquired with a flat couch for radiotherapy treatment planning

OBJECTIVES

To improve the integration of MRI with radiotherapy treatment planning, our department fabricated a flat couch top for our MR scanner. Setting up using this couch top meant that the patients were physically higher up in the scanner and, posteriorly, a gap was introduced between the patient and radiofrequency coil.

METHODS

Phantom measurements were performed to assess the quantitative impact on image quality. A phantom was set up with and without the flat couch insert in place, and measurements of image uniformity and signal to noise were made. To assess clinical impact, six patients with pelvic cancer were recruited and scanned on both couch types. The image quality of pairs of scans was assessed by two consultant radiologists.

RESULTS

The use of the flat couch insert led to a drop in image signal to noise of approximately 14%. Uniformity in the anteroposterior direction was affected the most, with little change in right-to-left and feet-to-head directions. All six patients were successfully scanned on the flat couch, although one patient had to be positioned with their arms by their sides. The image quality scores showed no statistically significant change between scans with and without the flat couch in place.

CONCLUSION

Although the quantitative performance of the coil is affected by the integration of a flat couch top, there is no discernible deterioration of diagnostic image quality, as assessed by two consultant radiologists. Although the flat couch insert moved patients higher in the bore of the scanner, all patients in the study were successfully scanned.

Increased prevalence and mortality in undiagnosed celiac disease

BACKGROUND & AIMS

The historical prevalence and long-term outcome of undiagnosed celiac disease (CD) are unknown. We investigated the long-term outcome of undiagnosed CD and whether the prevalence of undiagnosed CD has changed during the past 50 years.

METHODS

This study included 9133 healthy young adults at Warren Air Force Base (sera were collected between 1948 and 1954) and 12,768 gender-matched subjects from 2 recent cohorts from Olmsted County, Minnesota, with either similar years of birth (n = 5558) or age at sampling (n = 7210) to that of the Air Force cohort. Sera were tested for tissue transglutaminase and, if abnormal, for endomysial antibodies. Survival was measured during a follow-up period of 45 years in the Air Force cohort. The prevalence of undiagnosed CD between the Air Force cohort and recent cohorts was compared.

RESULTS

Of 9133 persons from the Air Force cohort, 14 (0.2%) had undiagnosed CD. In this cohort, during 45 years of follow-up, all-cause mortality was greater in persons with undiagnosed CD than among those who were seronegative (hazard ratio = 3.9; 95% confidence interval, 2.0-7.5; P < .001). Undiagnosed CD was found in 68 (0.9%) persons with similar age at sampling and 46 (0.8%) persons with similar years of birth. The rate of undiagnosed CD was 4.5-fold and 4-fold greater in the recent cohorts, respectively, than in the Air Force cohort (both P < or = .0001).

CONCLUSIONS

During 45 years of follow-up, undiagnosed CD was associated with a nearly 4-fold increased risk of death. The prevalence of undiagnosed CD seems to have increased dramatically in the United States during the past 50 years.

Handedness in the NAS/NRC twin study

In 1985, a hand preference survey was completed by 973 dizygotic and 1158 monozygotic male twin pairs, all veterans of World War II. This is the largest single twin study of handedness on record. As in state-of-the-art animal research, the laterality criterion was sensitive to both direction and consistency (degree, strong or weak) of handedness. Significant pairwise concordance was shown for the total group, and for consistency and directional factors separately. However, no zygosity differences were demonstrated.

MSTd neuronal basis functions for the population encoding of heading direction

Basis functions have been extensively used in models of neural computation because they can be combined linearly to approximate any nonlinear functions of the encoded variables. We investigated whether dorsal medial superior temporal (MSTd) area neurons use basis functions to simultaneously encode heading direction, eye position, and the velocity of ocular pursuit. Using optimal linear estimators, we first show that the head-centered and eye-centered position of a focus of expansion (FOE) in optic flow, pursuit direction, and eye position can all be estimated from the single-trial responses of 144 MSTd neurons with an average accuracy of 2-3 degrees, a value consistent with the discrimination thresholds measured in humans and monkeys. We then examined the format of the neural code for the head-centered position of the FOE, eye position, and pursuit direction. The basis function hypothesis predicts that a large majority of cells in MSTd should encode two or more signals simultaneously and combine these signals nonlinearly. Our analysis shows that 95% of the neurons encode two or more signals, whereas 76% code all three signals. Of the 95% of cells encoding two or more signals, 90% show nonlinear interactions between the encoded variables. These findings support the notion that MSTd may use basis functions to represent the FOE in optic flow, eye position, and pursuit.

Strongyloidiasis: an issue in Aboriginal communities

Strongyloidiasis, a disease caused by the parasitic gut nematode (roundworm), Strongyloides stercoralis, has the highest prevalence in the world in rural and remote Aboriginal communities of northern Australia. With prevalences greater than 25%, these communities have rates of strongyloidiasis higher those in the worst affected developing countries where surveys have been recently conducted. Available data indisputably support that strongyloidiasis is more prevalent in rural and remote Aboriginal communities than in the mainstream Australian community. However control of strongyloidiasis has not been given a high priority by government health departments, with the result that Aboriginal people in remote and rural communities in Northern Australia are still suffering from a preventable and treatable disease. This article suggests that the only way to address the strongyloidiasis problem in Indigenous communities is to have strongyloidiasis recognised and addressed at the national level. One component of this must be making health departments responsible for establishing appropriate systems of effective treatment for and monitoring of patients with strongyloidiasis.

Reply to Fudin's comments on Hudesman, Page, and Rautianen's experiment on the use of subliminal psychodynamic activation to enhance mathematics learning

Fudin in 1993 raises a number of methodological concerns that he believes limit the generalizability of the 1992 results obtained by Hudesman, Page, and Rautianen. We believe that the conclusions presented are appropriate to the procedures and results.

Reply to Fudin's (1993B) comments on Hudesman and Page's response to Fudin's (1993A) comments on Hudesman, Page, and Rautiainen's subliminal psychodynamic activation experiment

Fudin (1993b) raises two methodological concerns that he believes limit the usefulness of the results obtained by Hudesman, Page, and Rautiainen (1992). We have again attempted to address Fudin's concern. The authors believe that the conclusions presented are appropriate to the procedure and results.

Use of subliminal stimulation to enhance learning mathematics

24 students, who participated in a summer session mathematics enrichment program, viewed subliminally presented messages. Prior to each class, the experimental group of 16 viewed a subliminally presented psychoanalytic merging message and the control group of 8 viewed a neutral message. After 20 sessions students were retested. Experimental students had higher mathematics scores than controls. These data are compared with results obtained by other investigators.

Acromegaly and gastrointestinal cancer

A cohort of 1041 men who were discharged from the hospital with a diagnosis of acromegaly were examined for subsequent cancer. With a mean follow-up time of 8.3 years, an increased rate of cancers of the digestive organs was observed (27 cases; standard incidence ratio [SIR], 2.0; 95% confidence interval [CI], 1.3 to 2.9). Rates were elevated for cancers of the esophagus (7 cases; SIR, 3.1), stomach (4 cases; SIR, 2.5), and colon (13 cases; SIR, 3.1). The increased risk of colon cancer in acromegaly is consistent with previous clinical reports and suggests opportunities for etiologic research and early cancer detection. It would seem prudent to also evaluate this risk in current research on the use of growth hormone in older individuals to increase muscle mass and reduce body fat.

Metastatic renal cell carcinoma mimicking pleural mesothelioma

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