162 research outputs found
Integrated cardiovascular/respiratory control in type 1 diabetes evidences functional imbalance : Possible role of hypoxia
Background: Cardiovascular (baroreflex) and respiratory (chemoreflex) control mechanisms were studied separately in diabetes, but their reciprocal interaction (well known for diseases like heart failure) had never been comprehensively assessed. We hypothesized that prevalent autonomic neuropathy would depress both reflexes, whereas prevalent autonomic imbalance through sympathetic activation would depress the baroreflex but enhance the chemoreflexes. Methods: In 46 type-1 diabetic subjects (7.0 +/- 0.9 year duration) and 103 age-matched controls we measured the baroreflex (average of 7 methods), and the chemoreflexes, (hypercapnic: ventilation/carbon dioxide slope during hyperoxic progressive hypercapnia; hypoxic: ventilation/oxygen saturation slope during normocapnic progressive hypoxia). Autonomic dysfunction was evaluated by cardiovascular reflex tests. Results: Resting oxygen saturation and baroreflex sensitivity were reduced in the diabetic group, whereas the hypercapnic chemoreflex was significantly increased in the entire diabetic group. Despite lower oxygen saturation the hypoxic chemoreflex showed a trend toward a depression in the diabetic group. Conclusion: Cardio-respiratory control imbalance is a common finding in early type 1 diabetes. A reduced sensitivity to hypoxia seems a primary factor leading to reflex sympathetic activation (enhanced hypercapnic chemoreflex and baroreflex depression), hence suggesting a functional origin of cardio-respiratory control imbalance in initial diabetes. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe
Pseudogap and superconductivity in two-dimensional doped charge-transfer insulators
High-temperature superconductivity emerges in the CuO plane upon doping a
Mott insulator. To ascertain the influence of Mott physics plus short-range
correlations, we solve a three-band copper-oxide model in the charge-transfer
regime using cellular dynamical mean-field theory with continuous-time quantum
Monte Carlo as an impurity solver. We report the normal and superconducting
phase diagram of this model as a function of doping, interaction strength and
temperature. Upon hole doping of the charge-transfer insulator, the phase
boundary between pseudogap and correlated metal consists of a first-order
transition line at finite doping ending at a critical point, as in the one-band
model. Beyond the endpoint, the phase boundary continues as a Widom crossover
line, across which thermodynamic quantities peak. This phase boundary
determines changes in the pairing mechanism and is an emergent phenomenon
characteristic of doped Mott insulators, independent of many microscopic
details. Broader implications are discussed.Comment: 6 pages, 4 figures and supplementary information; published versio
Effects of interaction strength, doping, and frustration on the antiferromagnetic phase of the two-dimensional Hubbard model
Recent quantum-gas microscopy of ultracold atoms and scanning tunneling
microscopy of the cuprates reveal new detailed information about doped Mott
antiferromagnets, which can be compared with calculations. Using cellular
dynamical mean-field theory, we map out the antiferromagnetic (AF) phase of the
two-dimensional Hubbard model as a function of interaction strength , hole
doping and temperature . The N\'eel phase boundary is non-monotonic
as a function of and . Frustration induced by second-neighbor
hopping reduces N\'eel order more effectively at small . The doped AF is
stabilized at large by kinetic energy and at small by potential energy.
The transition between the AF insulator and the doped metallic AF is
continuous. At large , we find in-gap states similar to those observed in
scanning tunneling microscopy. We predict that, contrary to the Hubbard bands,
these states are only slightly spin polarized.Comment: 6 pages, 3 figures and supplemental informatio
Weekly paclitaxel as first-line chemotherapy in elderly advanced breast cancer patients: a phase II study of the Gruppo Italiano di Oncologia Geriatrica (GIOGer)
Background: First-line chemotherapy regimens suitable for elderly advanced breast cancer patients
are still not defined.
Patients and methods: Women with stage III or IV breast cancer aged >_70 years were enrolled in a
phase II study aimed to evaluate both activity and toxicity of weekly paclitaxel. Among 46 planned
patients, at least 18 responses and not more than seven unacceptable toxic events are required for a
favourable conclusion. Paclitaxel 80 mg/m2 was administered weekly for 3 weeks every 28 days.
Results: Unacceptable toxicity occurred in seven out of 46 patients evaluated for toxicity [15.2%;
exact 95% confidence interval (CI) 7.6% to 28.2%] and was represented by one case of febrile
neutropenia, one case of severe allergic reaction and five cases of cardiac toxicity. Among 41 patients
evaluated for response, a complete response occurred in two (4.9%) patients and a partial response
in 20 (48.8%), with an overall response rate of 53.7% (exact 95% CI 38.7% to 67.9%). The median
progression-free survival was 9.7 months (95% CI 8.5\u201318.7) and median survival was 35.8 months
(95% CI 19\u2013not defined).
Conclusions: Weekly paclitaxel is highly active in elderly advanced breast cancer patients. Data on
cardiovascular complications, however, indicate the need for a careful monitoring of cardiac function before and during chemotherap
Signatures of the Mott transition in the antiferromagnetic state of the two-dimensional Hubbard model
The properties of a phase with large correlation length can be strongly
influenced by the underlying normal phase. We illustrate this by studying the
half-filled two-dimensional Hubbard model using cellular dynamical mean-field
theory with continuous-time quantum Monte Carlo. Sharp crossovers in the
mechanism that favors antiferromagnetic correlations and in the corresponding
local density of states are observed. These crossovers occur at values of the
interaction strength and temperature that are controlled by the
underlying normal-state Mott transition.Comment: 5 pages, 3 figures and 4 appendices; published versio
Intermittent docetaxel chemotherapy as first-line treatment for metastatic castration-resistant prostate cancer patients
Aims: The intermittent administration of chemotherapy is a means of preserving patients' quality of life (QL). The aim of this study was to verify whether the intermittent administration of docetaxel (DOC) improves the patients' QL. Patients & methods: All patients received DOC 70 mg/m every 3 weeks for eight cycles. The patients were randomized to receive DOC continuously or with a fixed 3-month interval after the first four DOC courses. Results: The study involved 148 patients. There was no difference in QL between the groups receiving intermittent or continuous treatment. Intermittence had no detrimental effects on disease control. Conclusion: Although feasible and not detrimental, our results showed that true intermittent chemotherapy in metastatic castration-resistant prostate cancer patients failed to improve the patients' QL
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