Biphasic responses of the brachial artery diameter following forearm occlusion: a blunted response in the elderly

BACKGROUND: The purpose was to examine the temporal response of the brachial artery diameter following 5 minutes of forearm occlusion in young men. A secondary objective was to compare the main features of the temporal pattern between young and old. METHODS: Sixteen young (28 ± 8 yrs) and fifteen older (85 ± 8 yrs) men underwent high-resolution ultrasonography of the brachial artery before and after five minutes of forearm occlusion. RESULTS: Following release of the pressure cuff the brachial artery diameter exhibits a temporal biphasic response. Initially, there is a significant reduction in brachial diameter (NIL) compared to baseline (BASE), followed by a rapid increase to a PEAK at 41 sec post release. When comparing the magnitude of the decrease in diameter and the Brachial Artery Flow Mediated Dilation (BAFMD) between Young and Old, older subjects demonstrated a blunted response (Magnitude of Decrease: Young: 2.0%; Old: 0.4%, p = 0.015, and BAFMD: Young: 7.7%; Old: 2.3%, p = 0.001). Finally, a significant relationship was noted between the magnitude of decrease and BAFMD (r = -0.44, p = 0.04). CONCLUSION: Examination of the temporal response of the brachial artery diameter following 5 minutes of forearm occlusion reveals a biphasic pattern in all participants. Specific features of this pattern are blunted in older adults compared with younger subjects. Finally, the magnitude of the drop in diameter following forearm occlusion correlates with the magnitude of the BAFMD

A Holocene "frozen accident": sediments of extreme paleofloods and fires in the bedrock-confined upper Huis River, Western Cape, South Africa

Wildfires and flooding events are common and are forceful intrinsic controls over landscape evolution, biodiversity, and preserved sediment architecture in dryland environments. Charcoal-bearing Holocene flood sediments of the upper Huis River provide a rare perspective on the powerful and episodic sedimentary processes in a bedrock-confined fluvial setting in the tectonically stable SW Cape Fold Belt in South Africa. The sediments described in this paper are associated with high-magnitude, debris-flow-dominated paleofloods, and their charcoal content is linked to a series of radiocarbon-dated Holocene paleofires that occurred from ∼ 2165 ± 37 BP to ∼ 653 ± 35 BP. The five sedimentary facies associations are documented as products of: a) noncohesive pseudoplastic debris flows; b) transitional, high-matrix-strength debris flows with heterogeneous fluid content and flow behavior; c) low-cohesion debris flows; d) hyperconcentrated flows; and e) fluvial channel flow in the upper Huis River. The last is interpreted mainly from massive, subrounded to subangular boulder bars, which provide key evidence for the dramatic scouring of the upper Huis valley. The paleofloods, which not only filled the valley with debris-flow sediments up to 12 m thick, but also subsequently flushed it out nearly to the bedrock, had estimated extreme discharges of few thousands of m3/s. In summary, the upper Huis River sediments are exceptional because they preserve the geological record of recurring fires, and at least three extreme paleofloods (i.e., massive sedimentation events) over a period of ∼ 1500 years in an area typified by the fire-prone and fire-dependent Fynbos Biome. Furthermore, this study provides insights into what the gaps in the commonly fragmented bedrock-confined alluvial stratigraphic record would be like, should there be “more record than gap.

Profiling human breast epithelial cells using single cell RNA sequencing identifies cell diversity.

Breast cancer arises from breast epithelial cells that acquire genetic alterations leading to subsequent loss of tissue homeostasis. Several distinct epithelial subpopulations have been proposed, but complete understanding of the spectrum of heterogeneity and differentiation hierarchy in the human breast remains elusive. Here, we use single-cell mRNA sequencing (scRNAseq) to profile the transcriptomes of 25,790 primary human breast epithelial cells isolated from reduction mammoplasties of seven individuals. Unbiased clustering analysis reveals the existence of three distinct epithelial cell populations, one basal and two luminal cell types, which we identify as secretory L1- and hormone-responsive L2-type cells. Pseudotemporal reconstruction of differentiation trajectories produces one continuous lineage hierarchy that closely connects the basal lineage to the two differentiated luminal branches. Our comprehensive cell atlas provides insights into the cellular blueprint of the human breast epithelium and will form the foundation to understand how the system goes awry during breast cancer

Glioma Mimics: Magnetic Resonance Imaging Characteristics of Granulomas in Dogs

Granulomas can “mimic” gliomas on magnetic resonance imaging (MRI) in human patients. The goal of this retrospective study was to report canine brain granulomas that were consistent with glioma based upon MRI, report their histologic diagnosis, and identify MRI criteria that might be useful to distinguish granuloma from glioma. Ten granulomas, initially suspected to be glioma based on MRI, were ultimately diagnosed as granulomatous meningoencephalomyelitis (n = 5), infectious granulomas (n = 3) or other meningoencephalitis (n = 2). Age was 1.6–15.0 years and two dogs were brachycephalic breeds. MRI characteristics overlapping with glioma included intra-axial, heterogeneous, T2-weighted hyperintense, T1-weighted hypointense to isointense mass lesions with contrast-enhancement. Signals on fluid attenuation inversion recovery, gradient echo and diffusion weighted imaging also matched glioma. Peri-lesional edema and mass effect were toward the high end of findings reported for glioma. MRI characteristics that would be considered unusual for glioma included dural contact (n = 4), T2-hypointensity (n = 2), concomitant meningeal-enhancement (n = 9), and minor changes in the contralateral brain (n = 2). Cerebrospinal fluid analysis revealed albuminocytological dissociation or mild pleocytosis. These cases show that granulomas can “mimic” glioma on canine brain MRI. In individual cases, certain MRI findings may help increase the index of suspicion for granuloma. Lack of pronounced cerebrospinal fluid pleocytosis does not exclude granuloma. Signalment is very useful in the suspicion of glioma, and many of these dogs with granuloma were of ages and breeds in which glioma is less commonly seen

Designing medical technology for developing countries

Resource-poor countries have markedly different healthcare systems. Many developed nations donate medical supplies to these countries, but this often does not meet the needs of the recipients. Our goal is to develop simple healthcare solutions that can be produced in-country so the developing area does not depend on outside sources for its supplies. Our group works on many projects, including sustainable woven grass neck braces and a variety of low-cost sensors. Our designs do not require frequent donations, minimize the use of consumables, and provide better detection and/or treatment of prevalent medical concerns. Our baby monitor will detect skin temperature and control a heating element based on the needs of the infant. Our low-cost glucometer operates with the use of test strips that can be printed for a penny with a standard inkjet printer. This will allow the hospital or clinic to print the strips themselves rather than depend on donated strips. Our bacterial sensor will measure resistance to quickly detect the quantity of bacteria in a sample. We seek sustainable solutions for in-house manufacturing to advance more self-sufficient healthcare systems

Gender Differences in Symptoms of Myocardial Ischaemia

Aims Better understanding of symptoms of myocardial ischaemia is needed to improve timeliness of treatment for acute coronary syndromes (ACS). Although researchers have suggested sex differences exist in ischaemic symptoms, methodological issues prevent conclusions. Using percutaneous coronary intervention (PCI) balloon inflation as a model of myocardial ischaemia, we explored sex differences in reported symptoms of ischaemia. Methods and results Patients having non-emergent PCI, but not haemodynamic instability or left bundle branch block or non-acute coronary occlusion, were prospectively recruited. Pre-procedure, descriptions of pre-existing symptoms were obtained using open-ended questioning. Inflation was maintained for 2 min or until moderate discomfort or clinical instability occurred. During inflation, subjects were exhaustively questioned about their symptoms. Concurrent ECG data were collected. The final sample was 305 [39.7% women; mean age 63.9 (±10.6)]. No sex differences were found in rates of chest or typical ischaemic discomfort, regardless of ischaemic status. Women were significantly more likely to report throat/jaw discomfort [odds ratio: 2.91; 95% confidence interval: 1.58–5.37] even after statistical adjustment for clinical and demographic variables. Conclusion This prospective study with ECG-affirmed ischaemia found no statistically significant differences in women\u27s and men\u27s rates of chest and other typical symptoms during ischaemia, although women were more likely to experience throat and jaw discomfort. Currently both popular press and some patient education materials suggest women experience myocardial ischaemia differently from men. Steps to ensure women and health professionals are alert for the classic symptoms of myocardial ischaemia in women, as well as men, may be warranted

Geographic potential of the world’s largest hornet, Vespa mandarinia Smith (Hymenoptera: Vespidae), worldwide and particularly in North America

The Asian giant hornet (AGH, Vespa mandarinia) is the world’s largest hornet, occurring naturally in the Indomalayan region, where it is a voracious predator of pollinating insects including honey bees. In September 2019, a nest of Asian giant hornets was detected outside of Vancouver, British Columbia; multiple individuals were detected in British Columbia and Washington state in 2020; and another nest was found and eradicated in Washington state in November 2020, indicating that the AGH may have successfully wintered in North America. Because hornets tend to spread rapidly and become pests, reliable estimates of the potential invasive range of V. mandarinia in North America are needed to assess likely human and economic impacts, and to guide future eradication attempts. Here, we assess climatic suitability for AGH in North America, and suggest that, without control, this species could establish populations across the Pacific Northwest and much of eastern North America. Predicted suitable areas for AGH in North America overlap broadly with areas where honey production is highest, as well as with species-rich areas for native bumble bees and stingless bees of the genus Melipona in Mexico, highlighting the economic and environmental necessity of controlling this nascent invasion