bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of pyrite microfabric as a key to tectono-thermal evolution of massive sulphide deposits – an example from Deri, southern Rajasthan, India
Authors: Tiwary Anju , Deb Mihir , Cook Nigel J. 
Published: July 2002

AbstractPyrite is an ubiquitous constituent of the Proterozoic massive sulphide deposit at Deri, in the South Delhi Fold Belt of southern Rajasthan. Preserved pyrite microfabrics in the Zn-Pb-Cu sulphide ores of Deri reveal a polyphase growth history of the iron sulphide and enable the tectono-thermal evolution of the deposit to be reconstructed.Primary sedimentary features in Deri pyrites are preserved as compositional banding. Regional metamorphism from mid-greenschist to low amphibolite facies is recorded by various microtextures of pyrite. Trails of fine grained pyrite inclusions within hornblende porphyroblasts define S1-schistosity. Pyrite boudins aligned parallel to S1 mark the brittle–ductile transformation of pyrite during the earliest deformation in the region. Isoclinal to tight folds (F1 and F2) in pyrite layers relate to a ductile deformation stage during progressive regional metamorphism. Peak metamorphic conditions around 550°C, an estimation supported by garnet–biotite thermometry, resulted in annealing of pyrite grains, while porphyroblastic growth of pyrite (up to 900 µm) took place along the retrogressive path. Brittle deformation of pyrite and growth of irregular pyritic mass around such fractured porphyroblasts characterize the waning phase of regional metamorphism. A subsequent phase of stress-free, thermal metamorphism is recorded in the decussate and rosette textures of arsenopyrite prisms replacing irregular pyritic mass. Annealing of such patchy pyrite provides information regarding the temperature conditions during this episode of thermal metamorphism which is consistent with the hornblendehornfels facies metamorphism interpreted from magnetite–ilmenite geothermometry (550°C) and sphalerite geobarometry (3.5 kbar). A mild cataclastic deformation during the penultimate phase produced microfaults in twinned arsenopyrite prisms.
Human skin–derived mast cells can proliferate while retaining their characteristic functional and protease phenotypes
Authors: Kambe Naotomo , Kambe Michiyo , Kochan Jarema P. , Schwartz Lawrence B. 
Published: July 2002

AbstractHuman mast cells in adult tissues have been thought to have limited, if any, proliferative potential. The current study examined mast cells obtained from adult skin and cultured in serum-free medium with recombinant human stem cell factor. During the first 4 weeks of culture, the percentages of mast cells increased from 10 to almost 100. After 8 weeks, a 150-fold increase in the number of mast cells was observed. When freshly dispersed mast cells were individually sorted onto human fibroblast monolayers and cultured for 3 weeks, one or more mast cells were detected in about two thirds of the wells, and in about two thirds of these wells the surviving mast cells showed evidence of proliferation, indicating most mast cells in skin can proliferate. Such mast cells all expressed high surface levels of Kit and FcεRI, each of which were functional, indicating IgE was not required for FcεRI expression on mast cells. Such mast cells also retained the MCTC protease phenotype of mast cells that normally reside in the dermis. After 4 to 8 weeks of culture these mast cells degranulated in response to substance P and compound 48/80, characteristics of skin-derived mast cells that persist outside of the cutaneous microenvironment.
Relationship between supramaximal flow during cough and mortality in motor neurone disease
Authors: Chaudri M.B. , Liu C. , Hubbard R. , Jefferson D. , Kinnear W.J. 
Published: July 2002

The main function of cough is clearance of intrathoracic airways. A normal cough is characterized by a transient increase in expiratory flow above the maximal flow-volume loop envelope, known as cough “spikes”. They may be absent in patients with motor neurone disease. The relationship between cough pattern, pulmonary function and survival was studied.Fifty-three patients were recruited (25 bulbar). Vital capacity, maximal inspiratory and expiratory mouth pressures and cough flow/volume curves were performed on all patients, and the presence or absence of spikes were recorded. The primary endpoints were mortality or initiation of ventilatory support over a period of 18 months.Thirty-five patients died over the 18-month period of the study (including the six who were started on noninvasive ventilation). Twelve of the 24 patients with spikes died compared to 23 out of 29 patients without spikes (p<0.05). Patients without spikes were more likely to be bulbar on clinical grounds (p<0.0001) and had poorer lung function.The results showed an association between the absence of cough spikes and increased mortality. However the main determinants of survival in motor neurone disease are age, vital capacity and inspiratory mouth pressure, and it remains to be shown whether regular monitoring of cough conveys any additional advantage.
Survey of flexible fibreoptic bronchoscopy in the United Kingdom
Authors: Smyth C.M. , Stead R.J. 
Published: July 2002

The practice of flexible bronchoscopy is not standardized. Current guidelines are concerned primarily with safety aspects of the procedure. In view of this, and the authors' own observations of individual variation in preparation and technique, a national survey of bronchoscopic procedure was performed to assess physicians' methods.A structured questionnaire was mailed to 547 consultant physicians in adult respiratory medicine. Physicians' routines of patient preparation, drug therapy, sampling methods, and experience of complications with the flexible bronchoscope were assessed.A 60% response (328 physicians) was obtained. Patient consent was obtained by a junior doctor in 31% of replies. 205 (63%) physicians gave benzodiazepine sedation, 46 (14%) used opioid, and 38 (12%) administered both. Ninety-four (29%) physicians prescribed an antimuscarinic agent, and 235 (74%) gave antibiotics to patients with mechanical heart valves. Only 22% of physicians monitored electrocardiogram and 10% monitored blood pressure during all procedures. Marked variance was noted in sampling routines of suspected lung tumours. Physicians who used fluoroscopic guidance for transbronchial lung biopsy reported a significantly lower incidence of pneumothorax requiring drain insertion over the previous 12 months compared to those who did not (2.68 of 1000versus9.17 of 1000, (p<0.03)), but no difference in the total incidence of pneumothorax. Only 87 (27%) of responders had performed transbronchial needle aspiration sampling over the previous 12 months.The preparation and practice of flexible bronchoscopy varies greatly for each physician. Use of radiographical screening for performing transbronchial lung biopsy was associated with a lower likelihood of pneumothorax requiring chest tube drainage.
Health-related quality of life in obstructive sleep apnoea
Authors: Lacasse Y. , Godbout C. , Sériès F. 
Published: July 2002

The identification of the areas of quality of life (QoL) most likely to be affected by obstructive sleep apnoea (OSA) would be an important step in the evaluation of the impact of the disease and its treatment modalities. The objective of this study was to describe the impact of OSA on patients' QoL.A list of 186 items potentially related to QoL of patients with OSA was constructed. From this list, consecutive patients were asked, at the time of the diagnosis, to identify the most significant items and to grade their importance on a 5‐point scale. The item impact was determined from the proportion of patients who identified it as important, and the mean importance score attributed to this item (impact score=frequency×importance).One hundred patients (82 male; mean age: 51 yrs) were interviewed. The items having the most important impact on QoL clustered into five domains: 1) daytime symptoms; 2) nocturnal symptoms; 3) limitation of activities; 4) emotions; and 5) interpersonal relationships.The impact of obstructive sleep apnoea on quality of life is not limited to excessive daytime sleepiness. Obstructive sleep apnoea significantly contributes to the impairment of all domains of what is usually referred to as “health-related quality of life”.
Once-daily tobramycin in the treatment of adult patients with cystic fibrosis
Authors: Whitehead A. , Conway S.P. , Etherington C. , Caldwell N.A. , Setchfield N. , Bogle S. 
Published: July 2002

The aim of this study was to test the equivalence of once- and thrice-daily dosing with tobramycin by comparing efficacy and safety in adult patients with cystic fibrosis.Sixty adult patients with an acute respiratory exacerbation were randomized to receive either 10 mg·kg−1tobramycin once-daily or 3.3 mg·kg−1tobramycin thrice-daily. Primary efficacy and safety endpoints were defined as changes in respiratory function and changes in renal function and hearing.Both groups showed a significant increase in respiratory function without a clinically significant change in renal function. For changes in forced vital capacity % predicted and serum potassium and magnesium levels, equivalence was demonstrated. For the variables forced expiratory volume in one second and forced mid-expiratory flow % pred and serum creatinine levels, there was insufficient power to demonstrate equivalence. One patient in each group showed bilateral impairment in pure tone audiogram after treatment.This study demonstrated significant clinical improvement with both once- and thrice-daily tobramycin dosing. Equivalence between the two regimens was shown for some, but not all primary endpoints. Once-daily dosing should be used with careful monitoring of safety and efficacy until large multicentre studies confirm these encouraging results.
European Community Respiratory Health Survey calibration project of dosimeter driving pressures
Authors: Ward R.J. , Ward C. , Johns D.P. , Skoric B. , Abramson M. , Walters E.H. 
Published: July 2002

Two potential sources of systematic variation in output from Mefar dosimeters, the system used in the European Community Respiratory Health Survey (ECRHS) study have been evaluated: individual nebulizer characteristics and dosimeter driving pressure.Output variation from 366 new nebulizers produced in two batches for the second ECRHS were evaluated, using a solute tracer method, at a fixed driving pressure. The relationship between dosimeter driving pressure was then characterized and between-centre variation in dosimeter driving pressure was evaluated in an Internet-based survey.A systematic difference between nebulizers manufactured in the two batches was identified. Batch one had a mean±sd output of 7.0±0.8 mg·s−1and batch two, 6.3±0.7 mg·s−1(p<0.005). There was a wide range of driving pressures generated by Mefar dosimeters as set, ranging between 70–245 kPa, with most outside the quoted manufacturer's specification of 180±5%. Nebulizer output was confirmed as linearly related to dosimeter driving pressure (coefficient of determination (R2)=0.99, output=0.0377×driving pressure–0.4151). The range in driving pressures observed was estimated as consistent with a variation of about one doubling in the provocative dose causing a 20% fall in forced expiratory volume in one second.Systematic variation has been identified that constitutes potentially significant confounders for between-centre comparisons of airway responsiveness in the European Community Respiratory Health Survey, with the dosimeter driving pressure representing the most serious issue. This work confirms the need for appropriate quality control of both nebulizer output and dosimeter driving pressure, in laboratories undertaking field measurements of airway responsiveness. In particular, appropriate data on driving pressures need to be collected and factored into between-centre comparisons. Comprehensive collection of such data to optimize quality control is practicable and has been instigated by the organizing committee for the European Community Respiratory Health Survey II.
Anti-angiogenic strategies and vascular targeting in the treatment of lung cancer
Authors: Brock C.S. , Lee S.M. 
Published: July 2002

The generation of new blood vessels, angiogenesis, is important for tumour proliferation and metastasis. This involves a number of interacting processes and factors, such as growth factors and the receptor tyrosine kinases, matrix metalloproteinases and integrins.Studies have shown that tumour vascularity and the overexpression of growth factors and their receptors are of independent prognostic importance in different cancers, including lung cancer.The present article provides a background to angiogenesis and describes the potential targets for anti-angiogenic and vascular targeting strategies in cancer, focusing specifically on carcinoma of the lung. It also describes the anti-angiogenic drugs presently under phase I, II and III investigation and highlights some of the problems associated with the standard methodologies for assessing tumour response and drug efficacy using these agents.
Skeletal muscle fibre-type shifting and metabolic profile in patients with chronic obstructive pulmonary disease
Authors: Gosker H.R. , van Mameren H. , van Dijk P.J. , Engelen M.P.K.J. , van der Vusse G.J. , Wouters E.F.M. , Schols A.M.W.J. 
Published: July 2002

The aim of this study was to examine the nature of fibre-type redistribution in relation to fibre metabolic profile in the vastus lateralis in chronic obstructive pulmonary disease (COPD) and COPD subtypes.Fifteen COPD patients (eight with emphysema stratified by high-resolution computed tomography) and 15 healthy control subjects were studied. A combination of myofibrillar adenosine triphosphatase staining and immunohistochemistry was used to identify pure, as well as hybrid fibre types. For oxidative capacity, fibres were stained for cytochromecoxidase and succinate dehydrogenase activities, and glycogen phosphorylase for glycolytic capacity.The proportion of type‐I fibres in COPD patients was markedly lower (16%versus42%), especially in emphysema, and the proportion of hybrid fibres was higher (29%versus16%) compared to controls. The proportion of fibres staining positive for oxidative enzymes was lower in COPD patients, which correlated with the proportion of type‐I fibres. In COPD oxidative capacity was lower within IIA fibres.The authors conclude that fibre-type transitions are involved in the fibre-type redistribution in chronic obstructive pulmonary disease. Low oxidative capacity is closely related to the proportion of type‐I fibres, but an additional reduction of oxidative enzyme activity is present within IIA fibres. Fibre-type abnormalities may be aggravated in emphysema.
Role of tyrosine phosphatase in the modulation of pulmonary vascular tone
Authors: Huang X.L. , El Kebir D. , De Buys Roessingh A.S. , Schneider J.C. , Jacob L. , Mercier J.C. , Dall'Ava-Santucci J. , Dinh-Xuan A.T. 
Published: July 2002

In the vascular system, synthesis of the potent vasodilator nitric oxide (NO) is tightly regulated by the constitutively expressed endothelial NO synthase (eNOS). Activity of eNOS is controlled by Ca2+/calmodulin and various seryl/threonyl protein kinases. Less is known about the importance of phosphorylation and dephosphorylation of tyrosyl residues. Therefore the role of tyrosine phosphatase on the modulation of isolated rat pulmonary artery tone has been assessed. Inhibition of tyrosine phosphatase by sodium orthovanadate (SOV, 1×10−6 M) significantly: 1) increased phenylephrine-induced vasoconstriction and 2) decreased endothelium-dependent relaxation to acetylcholine, but had no effect on endothelium-independent relaxation to the NO donor, sodium nitroprusside. In phenylephrine-precontracted pulmonary arterial rings, SOV (1×10−7–1×10−5 M) had no effect on vascular tone but significantly relaxed rings which were pretreated with the NO-synthase inhibitor,Nω‐nitro‐l‐arginine-methyl ester (l‐NAME). SOV-induced relaxation in the presence of l‐NAME was, however, abolished by glibenclamide.In conclusion, inhibition of tyrosine phosphatase altered pulmonary vascular tone by increasing vasoconstrictor response to phenylephrine and decreasing endothelium-dependent relaxation to acetylcholine. Furthermore, the tyrosine phosphatase inhibitor, sodium orthovanadate, exhibited original vasodilator properties which were only observed when nitric oxide synthesis was inhibited. Thus a new pathway involving the inhibitory effect of nitric oxide on a glibenclamide-sensitive diffusible relaxing factor, that might play an important role in the control of pulmonary vascular tone is described.
Perspectives on Medical School Admission for Black Students Among Premedical Advisers at Historically Black Colleges and Universities
Authors: Weiss Jasmine , Nguementi Tiako Max Jordan , Akingbesote Ngozi D. , Keene Danya , Balasuriya Lilanthi , Sharifi Mona , Genao Inginia , Latimore Darin 
Published: October 2024

ImportanceThere remains a lack of representation of Black physicians in the physician workforce despite decades of national efforts to increase diversity. Historically Black Colleges and Universities (HBCUs) contribute to increasing representation in the workforce in the US. There is limited literature exploring the experiences of HBCU premedical students navigating the journey to medical school.ObjectiveTo examine barriers to and facilitators of medical school matriculation among Black students by exploring the perspectives of premedical student advisers at HBCUs.Design, Setting, and ParticipantsIn this qualitative study, HBCU advisers participated in a focus group in October 2019 or in semistructured interviews from January 2020 to March 2021. Using purposive sampling, premedical student advisers were recruited from different educational backgrounds and geographic locations and conducted 1-on-1 interviews. Data analysis was performed from March 2021 to March 2022.Main Outcomes and MeasuresThe main outcome was the experiences of HBCU premedical students navigating to medical school from the perspective of premedical advisers. An inductive approach to generate codes from the interviews and the focus groups was applied by reviewing transcripts and noting concepts and themes associated with advising strategies and student experiences.ResultsAmong the 26 participants, 18 (69.2%) were female, 13 (50.0%) had a doctorate degree, and 8 (30.8%) had more than 10 years of experience as advisers. Participants described 3 major themes: (1) the complex institutional relationship dynamics between undergraduate HBCUs and medical schools, (2) concerns about preferential treatment for students from predominantly white undergraduate schools when accessing clinical shadowing opportunities, and (3) the “it takes a village mindset” emphasizing family and peer involvement.Conclusions and RelevanceIn this qualitative study, barriers to medical school matriculation included concerns for the preferential treatment of students from predominantly white institutions when engaging with medical schools and a lack of access to clinical opportunities for HBCU students. The findings suggest that medical schools should continue to build collaborative partnerships with HBCUs to ensure equitable access to opportunities that prepare students for medical school.
Cognitive status and demographics modify the association between subjective cognition and amyloid
Authors: Bolton Corey J. , Khan Omair A. , Liu Dandan , Wilhoite Sydney , Dumitrescu Logan , Peterson Amalia , Blennow Kaj , Zetterberg Henrik , Hohman Timothy J. , Jefferson Angela L. , Gifford Katherine A. 
Published: October 2024

AbstractObjectiveThis study examined the effect of cognitive status, education, and sex on the association between subjective cognitive decline (SCD) and Alzheimer's disease (AD) biomarkers in non‐demented older adults.MethodsVanderbilt Memory and Aging Project participants (n = 129), dementia or stroke free, completed fasting lumbar puncture, SCD assessment, and cognitive assessment. Cerebrospinal fluid (CSF) biomarkers for AD were analyzed. Linear regression models related SCD to CSF AD biomarkers and follow‐up models assessed interactions of SCD × cognitive status, sex, reading level, and education on AD biomarkers.ResultsIn main effect models, higher SCD was associated with more amyloidosis (p‐values <0.004). SCD was not associated with tau, p‐tau, or neurofilament light (NFL) levels (p‐values >0.38). SCD score interacted with cognitive status (p < 0.02), sex (p = 0.03), and education (p‐values <0.005) on amyloidosis. In stratified models, higher SCD was associated with more amyloid in cognitively unimpaired (p‐values <0.003), men (p = 0.0003), and higher education. No SCD score × reading‐level interaction was found (p‐values >0.51) though SCD related to amyloid markers in the higher reading‐level group (p‐values <0.004).InterpretationHigher SCD was associated with greater cerebral amyloid accumulation, one of the earliest pathological AD changes. SCD appears most useful in detecting early AD‐related brain changes prior to objective cognitive impairment, in men, and those with higher quantity and quality of education and highlight the importance of considering these factors.
Association between atherosclerotic disease and cervical artery dissection in a population‐based cohort of older people
Authors: Kahan Joshua , Zhang Cenai , Liberman Ava L. , Segal Alan Z. , Murthy Santosh B. , Kim Jiwon , Kamel Hooman , Merkler Alexander E. 
Published: October 2024

AbstractObjectivesMany cases of cervical artery dissection are considered “spontaneous.” Recent data suggest that while cervical artery dissection may proportionally explain more strokes in young patients, hospitalization for dissection increases with age, suggesting a potential role of acquired vascular disease. In this study, we hypothesized that traditional vascular risk factors and comorbidities are associated with cervical artery dissection.MethodsWe performed a retrospective cohort study using administrative claims data from a 5% sample of Medicare beneficiaries. Exposures of interest included traditional vascular risk factors and comorbidities: coronary artery disease, hyperlipidemia, hypertension, diabetes mellitus, heart failure, chronic kidney disease, chronic obstructive pulmonary disease, valvular heart disease, atrial fibrillation, tobacco use, and alcohol abuse. The primary outcome was a new diagnosis of cervical artery dissection. Marginal structural Cox models were used to characterize the association between the exposures and outcomes, adjusted for time‐dependent confounding.ResultsAmong 2,256,710 eligible Medicare beneficiaries, 730 (0.03%) developed cervical artery dissection. The following exposures were found to be significantly associated with the development of cervical artery dissection: hypertension (HR 1.84 [95% CI: 1.40–2.41]), alcohol use (HR 1.83 [1.52–2.21]), atrial fibrillation (HR 1.80 [1.53–2.11]), tobacco use (HR 1.80 [1.52–2.13]), coronary artery disease (HR 1.56 [1.33–1.82]), and valvular heart disease (HR 1.23 [1.05–1.45]).InterpretationIn a large cohort of older people, several traditional vascular risk factors and comorbidities were associated with subsequent cervical artery dissection. Further studies exploring the role of such factors in the development of cervical artery dissection are warranted.