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1.
J Nippon Med Sch ; 91(3): 322-327, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38972745

RESUMEN

BACKGROUND: The differences in the characteristics of ischemic stroke associated with a mobile versus nonmobile residual left atrial thrombus (LAT) are unclear. We investigated whether the mobility of an LAT detected by transthoracic echocardiography is associated with the clinical features of stroke. METHODS: This study included 20 consecutive patients with nonvalvular atrial fibrillation who were admitted to our hospital for treatment of acute ischemic stroke and then found to have an LAT on transthoracic echocardiography. The patients were divided into two groups: those with a mobile LAT (Group M) and those with a nonmobile LAT (Group N). The clinical, neuroradiological, and echocardiographic variables were assessed. RESULTS: The LAT was mobile in 11 patients (Group M) and nonmobile in nine patients (Group N). The median National Institutes of Health Stroke Scale score on admission was higher in Group M than N (17 vs. 7, respectively; p=0.196). Four patients in Group M and one in Group N developed in-hospital stroke recurrence (36% vs. 11%, respectively; p=0.319). The prevalence of large vessel occlusion (15 events in Group M and 10 events in Group N, including in-hospital recurrent events) was significantly higher in Group M than N (73% vs. 30%, respectively; p=0.049), which seemed to lead to poorer functional outcomes in Group M than N (ratio of modified Rankin scale score of 0-2 at discharge: 18% vs. 44%, respectively; p=0.336). CONCLUSIONS: The mobility of LAT may affect stroke severity in patients with nonvalvular atrial fibrillation.


Asunto(s)
Fibrilación Atrial , Ecocardiografía , Atrios Cardíacos , Índice de Severidad de la Enfermedad , Trombosis , Humanos , Fibrilación Atrial/complicaciones , Masculino , Femenino , Anciano , Trombosis/etiología , Trombosis/diagnóstico por imagen , Atrios Cardíacos/diagnóstico por imagen , Atrios Cardíacos/fisiopatología , Anciano de 80 o más Años , Persona de Mediana Edad , Accidente Cerebrovascular Isquémico/complicaciones , Accidente Cerebrovascular Isquémico/etiología , Recurrencia , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/etiología , Cardiopatías/complicaciones , Cardiopatías/etiología
3.
Int J Mol Sci ; 25(11)2024 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-38891965

RESUMEN

Cardioembolic stroke accounts for over 20% of ischemic strokes and is associated with worse outcomes than other types of strokes. Atrial fibrillation (AF) is the most common risk factor for cardioembolic stroke. In this narrative review, we present an update about cardioembolic stroke mainly related to AF and atrial cardiopathy. Direct oral anticoagulants (DOACs) have revolutionized stroke prevention in patients with AF; however, their efficacy in preventing recurrent embolic stroke of unknown source remains uncertain. Various cardiac monitoring methods are used to detect AF, which is crucial for preventing stroke recurrence. DOACs are preferred over warfarin for AF-related stroke prevention; however, the timing of initiation after acute ischemic stroke is debated. Resuming anticoagulation after intracerebral hemorrhage in AF patients requires careful assessment of the risks. While catheter ablation may reduce the incidence of cardiovascular events, its effect on stroke prevention is unclear, especially in heart failure patients. Atrial cardiopathy is the emerging cause of embolic stroke of unknown source, which indicates atrial structural and functional disorders that can precede AF. Future research should focus on refining stroke risk prediction models, optimizing AF detection, understanding the roles of ablation and anticoagulation in stroke prevention, and establishing atrial cardiopathy as a therapeutic target, which could significantly reduce the burden of stroke.


Asunto(s)
Anticoagulantes , Fibrilación Atrial , Accidente Cerebrovascular Embólico , Humanos , Accidente Cerebrovascular Embólico/etiología , Fibrilación Atrial/complicaciones , Anticoagulantes/uso terapéutico , Factores de Riesgo
4.
Intern Med ; 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38811226

RESUMEN

Essential thrombocythemia (ET) is a myeloproliferative neoplasm that is a rare cause of ischemic stroke. We herein report a 70-year-old man with JAK2 V617F mutation-positive ET who experienced ischemic stroke twice in 1 month due to transient stenosis. In both events, transient stenosis formed at the same curvature of the right middle cerebral artery, and the thrombus disappeared with the initiation of antiplatelet agents. The formation of in situ thrombus at the curvature of the intracranial vessels may be a unique characteristic of JAK2 V617F mutation-positive ET patients.

5.
Intern Med ; 2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38749725

RESUMEN

We herein report a 47-year-old woman who developed migraine-like headache with aura and subsequent multiple cerebral infarcts, likely due to severe iron deficiency anemia (IDA) from menorrhagia. The progression from IDA to ischemic stroke involves several pathophysiological mechanisms, including reduction of erythrocyte deformability, reactive thrombocytosis, and anemic hypoxia. We speculate that a microembolus first caused cortical spreading depression without infarcts and that a larger thromboembolus then caused multiple infarcts. This case highlights the transition from migraine-like headache to ischemic stroke. New-onset migraine-like headache is a warning of impending ischemic stroke, and IDA may be a potential underlying cause.

6.
Oncol Res ; 32(4): 607-614, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38560568

RESUMEN

C-mannosylation is a post-translational modification that occurs intracellularly in the endoplasmic reticulum. In humans, biosynthesis of C-mannosylation in proteins containing thrombospondin type 1 repeat is catalyzed by the DPY19 family; nonetheless, biological functions of protein C-mannosylation are not yet fully understood, especially in tumor progression. Vasculogenic mimicry (VM) is the formation of fluid-conducting channels by highly invasive and genetically deregulated tumor cells, enabling the tumors to form matrix-embedded vasculogenic structures, containing plasma and blood cells to meet the metabolic demands of rapidly growing tumors. In this study, we focused on DPY19L3, a C-mannosyltransferase, and aimed to unravel its role in VM. Knockout of DPY19L3 inhibited the formation of VM in HT1080 human fibrosarcoma cells. Re-expression of wild-type DPY19L3 recovered VM formation; however, DPY19L3 isoform2, an enzymatic activity-defect mutant, did not restore it, suggesting that the C-mannosyltransferase activity of DPY19L3 is crucial to its function. Furthermore, the knockdown of DPY19L3 in MDA-MB-231 breast cancer cells hindered its network formation ability. Altogether, our findings suggest that DPY19L3 is required for VM formation and stipulate the relevance of C-mannosylation in oncogenesis.


Asunto(s)
Neoplasias de la Mama , Manosiltransferasas , Femenino , Humanos , Neoplasias de la Mama/patología , Línea Celular Tumoral , Manosiltransferasas/genética , Manosiltransferasas/metabolismo , Neovascularización Patológica/genética , Neovascularización Patológica/metabolismo
7.
J Prosthodont Res ; 68(3): 456-465, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38220162

RESUMEN

PURPOSE: This study aimed to elucidate the relationship between diurnal masseter muscle activity and awareness of diurnal awake bruxism (d-AB) by conducting a comparative analysis of electromyographic (EMG) data from individuals with and without awareness of diurnal awake bruxism (d-AB), utilizing EMG data gathered from multiple subjects. METHODS: Unilateral masseter electromyography (EMG) recordings were performed during the daytime using an ultraminiature wearable EMG device. A total of 119 participants (59 with awareness of diurnal tooth clenching [d-TC] and 60 without awareness of d-TC) were included. Waveforms longer than 0.25 s with the two amplitude conditions, exceeding twice the baseline and >5% of maximum voluntary clenching, were extracted. In addition, the number of bursts and episodes (groups of bursts), burst duration, and burst peak amplitude were calculated for each participant. RESULTS: There were no significant differences in the EMG parameters between the groups with and without awareness of d-TC. Additionally, the frequency distribution of the number of EMG waveforms exhibited wide ranges and substantial overlap between the two groups. CONCLUSIONS: The variability in the number of bursts and episodes, burst peak amplitude, and burst duration among subjects suggests the need for an objective classification of d-AB severity based on EMG values. The absence of significant differences and large overlap in frequency distributions between the groups with and without awareness of d-TC indicate difficulty in predicting muscle activity solely based on awareness of d-AB.


Asunto(s)
Concienciación , Bruxismo , Electromiografía , Músculo Masetero , Vigilia , Humanos , Músculo Masetero/fisiopatología , Músculo Masetero/fisiología , Bruxismo/fisiopatología , Masculino , Femenino , Adulto , Vigilia/fisiología , Concienciación/fisiología , Ritmo Circadiano/fisiología , Adulto Joven , Persona de Mediana Edad
8.
Intern Med ; 63(6): 847-852, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-37495531

RESUMEN

Essential thrombocythemia is a myeloproliferative neoplasm. Ischemic stroke is frequently the first manifestation of essential thrombocythemia. We herein report a patient with JAK2V617 mutation-positive essential thrombocythemia who developed recurrent ischemic stroke with rapid development of intracranial artery stenosis and subsequently underwent successful mechanical thrombectomy. The high JAK2V617F allele burden in our patient (58.4%) may have affected the patient's condition. We discuss similar reports in the literature and the possible pathophysiologic mechanism of large artery involvement in these patients.


Asunto(s)
Accidente Cerebrovascular Isquémico , Trombocitemia Esencial , Humanos , Constricción Patológica , Trombocitemia Esencial/complicaciones , Arterias , Infarto Cerebral , Mutación , Trombectomía , Janus Quinasa 2/genética
9.
Ann Med ; 55(2): 2279747, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37967233

RESUMEN

PURPOSE: The aim of this study is to establish a standardized measurement method and to examine the intra- and inter-reliabilities and absolute reliability of measuring skin mechanical properties using a skin elasticity meter (Cutometer®). METHODS: Ten healthy participated in the study. Skin mechanical properties were measured at four sites: upper arm, lower arm, upper leg and lower leg on both sides in supine position using a non-invasive skin elasticity meter by two trained different raters. The measurements include quantitative indices of the maximal distensibility (R0), elasticity (R2, R5, R7), and viscoelasticity (R6). Intra- and inter- relative reliabilities were determined using the intraclass correlation coefficient (ICC) (1,1) and ICC (2,1) methods, respectively. The absolute reliability was assessed via the Bland-Altman analysis. Moreover, we evaluated the minimal detectable change at a 95% confidence level (MDC95). RESULTS: At each site, the ICC (1,1) values were >0.90, and the ICC (2,1) values were >0.50. The Bland-Altman analysis did not reveal any fixed errors, and several sites and parameters have proportional errors. CONCLUSIONS: In this study, intra- and inter-reliabilities were measured at "excellent" and more than "moderate" levels, respectively. However, because some proportional errors were observed, the limits of reliability agreement should be considered when using the proposed methods. We believe that the results of this study can be applied to clinical research in field of rehabilitation treatment.


Asunto(s)
Piel , Humanos , Reproducibilidad de los Resultados , Elasticidad
10.
PM R ; 2023 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-37844015

RESUMEN

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for hematological malignancies. Several complications following allo-HSCT, such as graft-versus-host disease, infection, and malnutrition, often cause physical dysfunction, and the assessment of physical function and evaluation of muscle mass are incompletely performed. Use of ultrasound (US) allows muscle mass measurement in patients with poor general conditions. In allo-HSCT recipients, the correlation between physical function and muscle thickness, as measured by US, remains unclear. OBJECTIVE: To clarify whether muscle thickness measured by US correlated with physical function in allo-HSCT recipients. DESIGN: A single-center prospective cohort study. SETTING: Hospital. PATIENTS: Ninety-two patients underwent allo-HSCT at our hospital from April 2017 to March 2019. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE(S): Biceps and quadriceps muscle thickness measured by US, grip strength, isometric muscle strength (elbow flexion and knee extension), and 6-minute walking test (6MWT) before allo-HSCT and on days 30, 90, 180, 1 year, and 2 years after allo-HSCT. The implementation rates of these assessments were also investigated. RESULTS: Correlations were observed between biceps thickness and elbow flexion muscle strength/grip strength before allo-HSCT, on days 30, 90, 180, 1 year, and 2 years after allo-HSCT (r = 0.71/0.74, 0.73/0.72, 0.70/0.79, 0.67/0.75, 0.72/0.75, and 0.85/0.79, respectively, all p < .001). At the same time points, quadriceps thickness moderately correlated with knee extensor strength (r = 0.49, 0.50, 0.45, 0.64, 0.61, and 0.58, all p < .001). However, biceps and quadriceps thicknesses did not correlate with the 6MWT. The percentages of patients measured with US and 6MWT were 93.4% and 82.4% (p = .01) on day 30 and 97.5% and 87.8% (p = .02) on day 90, respectively. CONCLUSIONS: US assessment may be a useful alternative method for estimating muscle strength in fragile allo-HSCT recipients, particularly when physical function assessment is difficult to quantify.

11.
Keio J Med ; 72(4): 102-105, 2023 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-37743529

RESUMEN

We encountered a-27-year-old female patient who developed refractory severe headache and photophobia after the first dose of COVID-19 vaccine. Despite her prior history of migraine, we diagnosed COVID-19 vaccine-induced aseptic meningitis. Symptoms were significantly resolved after methylprednisolone therapy. On reviewing the literature, we could find only nine similar cases, with over half of them affecting women aged 20-40 years. Although uncommon, aseptic meningitis should be suspected in patients with persistent or delayed onset of headache following COVID-19 vaccination.


Asunto(s)
Vacuna BNT162 , COVID-19 , Meningitis Aséptica , Femenino , Humanos , Vacuna BNT162/efectos adversos , COVID-19/prevención & control , Cefalea/inducido químicamente , Meningitis Aséptica/inducido químicamente , Vacunación/efectos adversos , Adulto
12.
Jpn J Ophthalmol ; 67(5): 560-564, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37289297

RESUMEN

PURPOSE: Plate-haptic rotationally asymmetric multifocal toric intraocular lenses (IOL) (Lentis Comfort Toric) occasionally rotate extensively after surgery. We conducted the current study to investigate the incidence of extensive misalignment of this IOL and its association with clinical parameters. STUDY DESIGN: Retrospective case series. SUBJECTS AND METHODS: Data were collected from patients who had undergone phacoemulsification and implantation of a plate-haptic multifocal toric IOL. RESULTS: Among 332 eyes, extensive misalignment of toric IOLs ≥ 45º occurred in 3.3% (11 eyes). The amount of misalignment in eyes with extensive misalignment was 81.6 ± 22.9º, while in those without extensive misalignment, it was 3.0 ± 2.7º. The eyes with extensive misalignment showed significantly greater axial length (p < 0.001), larger corneal diameter (p = 0.034), and flatter corneas (p = 0.044) than those without extensive misalignment. Repositioning surgery to correct toric IOL misorientation was conducted in 9 eyes between 7 and 28 days after cataract surgery. In 2 eyes, repositioning surgery was carried out twice. CONCLUSIONS: In majority of cases plate-haptic multifocal toric IOLs showed satisfactory rotational stability, but extensive misalignment ≥ 45º occurred in 3.3% of cases.


Asunto(s)
Astigmatismo , Lentes Intraoculares , Facoemulsificación , Humanos , Implantación de Lentes Intraoculares , Agudeza Visual , Estudios Retrospectivos , Tecnología Háptica , Astigmatismo/cirugía , Astigmatismo/complicaciones , Refracción Ocular
13.
Kyobu Geka ; 76(6): 438-442, 2023 Jun.
Artículo en Japonés | MEDLINE | ID: mdl-37258021

RESUMEN

Giant atria may trigger respiratory failure, which often requires surgical intervention. We report a patient who presented with respiratory failure due to bilateral giant atria. The patient was a 75-year-old woman with rheumatic heart disease. She had undergone mitral valve replacement and tricuspid annuloplasty at another hospital 17 years ago but recently developed respiratory dysfunction. Compression to the lungs by enlarged atria was diagnosed as the main cause of respiratory dysfunction. Hence, the anterior-to-posterior left atrial wall was plicated by para-annular and superior-half plication, respectively, and the right atrial wall was excised into an ellipse shape. Tricuspid valvuloplasty was performed on four sets of eight artificial chordae with CV5 sutures and an annuloplasty ring. Respiratory failure was alleviated after the surgery.


Asunto(s)
Fibrilación Atrial , Insuficiencia de la Válvula Mitral , Insuficiencia Respiratoria , Insuficiencia de la Válvula Tricúspide , Femenino , Humanos , Anciano , Válvula Mitral/cirugía , Válvula Tricúspide/cirugía , Insuficiencia de la Válvula Tricúspide/cirugía , Insuficiencia Respiratoria/etiología , Insuficiencia Respiratoria/cirugía , Atrios Cardíacos/cirugía , Insuficiencia de la Válvula Mitral/cirugía
14.
Intern Med ; 62(8): 1145-1149, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36104190

RESUMEN

Extramedullary plasmacytoma (EMP) can rarely occur in conjunction with multiple myeloma (MM). EMPs are usually detected in the upper aerodigestive tract (UAD) but can also occur along the digestive tract. However, the involvement of gallbladder is uncommon. Gastrointestinal tract symptoms often lead to the diagnosis of EMP in the gallbladder. An 81-year-old man was referred to our hospital with suspected primary gallbladder carcinoma. He was subsequently operated on, and the pathological findings showed EMP of the gallbladder without MM.


Asunto(s)
Mieloma Múltiple , Plasmacitoma , Masculino , Humanos , Anciano de 80 o más Años , Plasmacitoma/diagnóstico por imagen , Plasmacitoma/cirugía , Vesícula Biliar/patología , Mieloma Múltiple/patología , Tracto Gastrointestinal/patología
15.
SAGE Open Med Case Rep ; 10: 2050313X221138652, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36467012

RESUMEN

Here we describe a case of open surgery for superior vena cava syndrome due to invasive thymoma. An 85-year-old woman presented with facial swelling and exertional dyspnea. Computed axial tomography revealed a thymoma in the mediastinum, extending to the superior vena cava, right atrium, and bilateral brachiocephalic veins. Endovascular therapy did not seem feasible because superior vena cava appeared totally occluded, and stenting could cause tumor embolism to the pulmonary arteries. Open surgery facilitated macroscopically complete and successful tumor resection. If long-term survival seems possible, open surgery could be a viable treatment option for superior vena cava syndrome that is ineligible for endovascular therapy.

16.
Brain Nerve ; 74(10): 1197-1204, 2022 Oct.
Artículo en Japonés | MEDLINE | ID: mdl-36198645

RESUMEN

Discovering that calcitonin-related peptide (CGRP) plays a key role in migraine pathophysiology has allowed us to develop new approaches for acute and preventive treatment. Monoclonal antibodies against CGRP and its receptor offer considerable improvements over existing drugs for migraine prevention. The serotonin 1F (5-HT 1F) receptor agonist lasmiditan can across the blood-brain barrier and act on peripheral and central nervous system sites without vasoconstriction by activating 5-HT1B. Migraine treatment has reached a new era with the development of drugs by translating basic research findings from the bench to the bedside.


Asunto(s)
Péptido Relacionado con Gen de Calcitonina , Trastornos Migrañosos , Anticuerpos Monoclonales/uso terapéutico , Calcitonina/uso terapéutico , Péptido Relacionado con Gen de Calcitonina/uso terapéutico , Humanos , Trastornos Migrañosos/tratamiento farmacológico , Serotonina/uso terapéutico
17.
Nat Commun ; 13(1): 5787, 2022 10 02.
Artículo en Inglés | MEDLINE | ID: mdl-36184671

RESUMEN

Antarctica is one of the most vulnerable regions to climate change on Earth and studying the past and present responses of this polar marine ecosystem to environmental change is a matter of urgency. Sedimentary ancient DNA (sedaDNA) analysis can provide such insights into past ecosystem-wide changes. Here we present authenticated (through extensive contamination control and sedaDNA damage analysis) metagenomic marine eukaryote sedaDNA from the Scotia Sea region acquired during IODP Expedition 382. We also provide a marine eukaryote sedaDNA record of ~1 Mio. years and diatom and chlorophyte sedaDNA dating back to ~540 ka (using taxonomic marker genes SSU, LSU, psbO). We find evidence of warm phases being associated with high relative diatom abundance, and a marked transition from diatoms comprising <10% of all eukaryotes prior to ~14.5 ka, to ~50% after this time, i.e., following Meltwater Pulse 1A, alongside a composition change from sea-ice to open-ocean species. Our study demonstrates that sedaDNA tools can be expanded to hundreds of thousands of years, opening the pathway to the study of ecosystem-wide marine shifts and paleo-productivity phases throughout multiple glacial-interglacial cycles.


Asunto(s)
Diatomeas , Regiones Antárticas , ADN Antiguo , Diatomeas/genética , Ecosistema , Eucariontes , Sedimentos Geológicos
18.
Paleoceanogr Paleoclimatol ; 37(7): e2022PA004433, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36247355

RESUMEN

Ice loss in the Southern Hemisphere has been greatest over the past 30 years in West Antarctica. The high sensitivity of this region to climate change has motivated geologists to examine marine sedimentary records for evidence of past episodes of West Antarctic Ice Sheet (WAIS) instability. Sediments accumulating in the Scotia Sea are useful to examine for this purpose because they receive iceberg-rafted debris (IBRD) sourced from the Pacific- and Atlantic-facing sectors of West Antarctica. Here we report on the sedimentology and provenance of the oldest of three cm-scale coarse-grained layers recovered from this sea at International Ocean Discovery Program Site U1538. These layers are preserved in opal-rich sediments deposited ∼1.2 Ma during a relatively warm regional climate. Our microCT-based analysis of the layer's in-situ fabric confirms its ice-rafted origin. We further infer that it is the product of an intense but short-lived episode of IBRD deposition. Based on the petrography of its sand fraction and the Phanerozoic 40Ar/39Ar ages of hornblende and mica it contains, we conclude that the IBRD it contains was likely sourced from the Weddell Sea and/or Amundsen Sea embayment(s) of West Antarctica. We attribute the high concentrations of IBRD in these layers to "dirty" icebergs calved from the WAIS following its retreat inland from its modern grounding line. These layers also sit at the top of a ∼366-m thick Pliocene and early Pleistocene sequence that is much more dropstone-rich than its overlying sediments. We speculate this fact may reflect that WAIS mass-balance was highly dynamic during the ∼41-kyr (inter)glacial world.

19.
SAGE Open Med Case Rep ; 10: 2050313X221112363, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35899248

RESUMEN

We present a case of redo stentless valve operation in a 73-year-old man who underwent aortic valve replacement via the subcoronary approach with a freestyle aortic bioprosthesis 23 years ago at our institution. He was referred for surgery because an echocardiogram showed severe aortic regurgitation due to structural valve deterioration, and aortic valve replacement was planned. Severe circumferential calcification and adhesion were noted during the surgery between the freestyle and native roots. Redo-aortic valve replacement was successful despite the technical difficulty. In stentless valve reoperations following aortic valve replacement via the subcoronary method, the planning of valve-in-valve transcatheter aortic valve implantation and sutureless valve implantation may be a practical and safe strategy.

20.
Nat Commun ; 13(1): 2044, 2022 04 19.
Artículo en Inglés | MEDLINE | ID: mdl-35440628

RESUMEN

The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO2 levels.


Asunto(s)
Polvo , Agua de Mar , Regiones Antárticas , Atmósfera , Polvo/análisis , Océanos y Mares
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