Comparison of resting metabolic rate prediction equations in college-aged adults.

Prediction equations have been considered an accurate method for estimating resting metabolic rate (RMR) across multiple populations, but their accuracy for college-aged individuals not on an athletics team remains to be determined. Sixty-two college-aged (18-30 yrs) males (n = 31) and females (n = 31) had their RMR measured (RMRm), using indirect calorimetry, and body composition assessed via air-displacement plethysmography. The World Health Organization (WHO), Mifflin-St Jeor (Mifflin), Harris-Benedict (HB), Cunningham, and Nelson equations were used to estimate RMR. No difference was observed between the Cunningham and RMRm regardless of sex (p ≥ 0.05). All other prediction equations estimated a significantly lower RMR for males (p < 0.05). The Mifflin and Nelson equations predicted an RMR that was significantly lower than RMRm for females (p < 0.05). When compared with RMRm, no difference was detected for females using the WHO, HB, or Cunningham (p ≥ 0.05). Only the Nelson equation predicted an RMR that was outside of the clinically acceptable range (±10% of RMRm) regardless of sex. The Cunningham, WHO, and HB equations can accurately predict RMR for college-aged males and females. RMR prediction equations used in this study are less accurate for those with greater RMRs. Novelty: For adults 18-30 years old that are not on an athletics team, the Cunningham equation can accurately predict RMR. The Nelson equation should not be used to predict RMR for this population. There is a systematic bias for RMR prediction equations to underestimate higher measured RMR values.

Cutaneous Cholangiocarcinoma: An Interesting Presentation.

This is a case of a 64-year-old white man with a history of CCA, originally diagnosed in May 2018 and returning in November 2019 with growing cutaneous nodules. These were removed for cosmetic and functional purposes. Pathologic findings of the lesions showed likely metastatic disease from his original CCA. This represents a relatively rare presentation of metastatic disease in the setting of CCA. In cases of CCA with metastatic spread, treatment is not curative and should be focused on measures to improve the patient's quality of life. This includes acceptable cosmesis, as well as factors aiding in completing activities of daily living.

AVPR1A distribution in the whole C57BL/6J mouse neonate.

The neuropeptide arginine vasopressin (AVP) plays significant roles in maintaining homeostasis and regulating social behavior. In vaginally delivered neonates, a surge of AVP is released into the bloodstream at levels exceeding release during life-threatening conditions such as hemorrhagic shock. It is currently unknown where the potential sites of action are in the neonate for these robust levels of circulating AVP at birth. The purpose of this study is to identify the location of AVP receptor 1a (AVPR1A) sites as potential peripheral targets of AVP in the neonatal mouse. RT-qPCR analysis of a sampling of tissues from the head demonstrated the presence of Avpr1a mRNA, suggesting local peripheral translation. Using competitive autoradiography in wildtype (WT) and AVPR1A knockout (KO) postnatal day 0 (P0) male and female mice on a C57BL/6J background, specific AVPR1A ligand binding was observed in the neonatal mouse periphery in sensory tissues of the head (eyes, ears, various oronasal regions), bone, spinal cord, adrenal cortex, and the uro-anogenital region in the neonatal AVPR1A WT mouse, as it was significantly reduced or absent in the control samples (AVPR1A KO and competition). AVPR1A throughout the neonatal periphery suggest roles for AVP in modulating peripheral physiology and development of the neonate.

Propagation of surface fissures in articular cartilage in response to cyclic loading in vitro.

BACKGROUND: Mechanical overloading of synovial joints can damage the articular cartilage surface and may lead to osteoarthritis. However, causal links between mechanical and biological events in cartilage are poorly understood. OBJECTIVES: To test the hypothesis that surface fissures in cartilage can propagate mechanically if the joint surface is subjected to vigorous cyclic loading. METHODS: Thirty-five cartilage-on-bone specimens, 15-mm square, were removed from mature bovine knee and shoulder joints. Specimens were loaded by means of a 9-mm-diameter flat indenter with a beveled edge, and their compressive strength determined. Failure occurred in the cartilage surface at an average stress of 36 MPa. Cartilage fissures were marked with Indian ink, photographed, and their length and width measured using image analysis software. Each damaged specimen was subjected to cyclic loading at 40% of its compressive strength, at 0.5 Hz, for up to 5 h. Fissure length and width were measured at regular intervals. After testing, fissure depth was measured from histological sections, and compared with measurements from damaged cartilage which was not cyclically loaded. RESULTS: Cyclic loading caused cartilage fissures to increase in length (mean 353%, P<0.01) and width (360%, P<0.01) but not depth. Propagation was rapid at first, but approached equilibrium after several hundred cycles. Rehydration in saline had no effect on fissure length, but width returned to pre-cyclic loading values. CONCLUSION: Cartilage fissures can propagate mechanically when a joint surface is subjected to cyclic compressive loading in vitro. The transient opening-up of fissures to form wide surface "wounds" during cyclic loading could be of biological significance if it occurred in living people. RELEVANCE: In living joints, wide open fissures in the cartilage surface could promote degenerative changes in the tissue.