542 research outputs found
A 10-Year Experience in Intraoperative Parathyroid Hormone Measurements for Primary Hyperparathyroidism: A Prospective Study of 91 Previous Unexplored Patients
Introduction. Primary hyperparathyroidism (PHP) is characteristically determined by high levels of calcium and high or inappropriate levels of parathyroid hormone (PTH). Technological advances have dramatically changed the surgical technique over the years once intraoperative parathyroid hormone (IOPTH) assay had allowed for focused approaches. Objective. To evaluate our 10-year experience in employing a rapid intraoperative PTH assay for PHP. Methods. A prospective cohort of 91 PHP-operated patients in a tertiary institution in São Paulo, Brazil, from June 2000 to April 2011. Results. We had 85 (93.4%) successful parathyroidectomies, 6 (6.6%) failed parathyroidectomies in 91 previous unexplored patients, and 5 (100%) successful remedial surgeries. The IOPTH was true-positive in 88.5%, true-negative in 7.3%, false-positive in 2.1%, and false-negative in 2.1% of the procedures. IOPTH was able to obviate additional exploration or to ask for additional exploration in 92 (95.8%) procedures. Conclusion. The IOPTH revealed to be an important technological adjunct in the current parathyroid surgery for PHP
Total Parathyroidectomy with Presternal Intramuscular Autotransplantation in Renal Patients: A Prospective Study of 66 Patients
Surgical treatment of secondary (SHPT) and tertiary hyperparathyroidism (THPT) may involve various surgical approaches. The aim of this paper was to evaluate presternal intramuscular autotransplantation of parathyroid tissue as a surgical option in SHPT and THPT treatment. 66 patients with renal chronic disease underwent surgery from April 2000 to April 2005 at Universidade Federal São Paulo, Brazil. There were 38 SHPT patients (24 women/14 men), mean age of 39.yrs (range: 14–58), and 28 THPT patients (14 women/14 men), mean age of 43.4 yrs (range: 24–62). Postoperative average followup was 42.9 months (range: 12–96). Postoperative intact PTH increased throughout followup from 73.5 pg/mL to 133 pg/mL on average from 1st to the 5th year, respectively, in SHPT and from 54.9 pg/mL to 94.7 pg/mL on average from 1st to 5th year, respectively, in THPT group. Definitive hypoparathyroidism was observed in 4 (6.06%) patients and graft-dependent recurrence in 6 (9.09%). Presternal intramuscular autotransplantation of parathyroid tissue is a feasible and safe surgical option in SHPT and THPT treatment
Fatal outcome in classic Kaposi's sarcoma
First described in 1872, Kaposi's sarcoma is defined as a rare multifocal tumor that originates in the endothelial cells and presents with cutaneous and extracutaneous manifestations. The classic form is most common in elderly men and progression is slow. This tumor responds well to chemotherapy and radiotherapy. This report describes a classic case of Kaposi's sarcoma in a woman with skin and visceral manifestations in whom the disease rapidly progressed to a fatal outcome.Descrito em 1872, o sarcoma de Kaposi é neoplasia multicêntrica rara originária de células endoteliais com manifestação cutânea e extracutânea. A forma clássica é muito mais frequente em homens idosos, com evolução prolongada e boa resposta a quimioterapia e radioterapia. Apresentaremos um caso de sarcoma de Kaposi clássico com comprometimento cutâneo e visceral em paciente do sexo feminino com rápida evolução fatal.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL
Variational state based on the Bethe ansatz solution and a correlated singlet liquid state in the one-dimensional t-J model
The one-dimensional t-J model is investigated by the variational Monte Carlo
method. A variational wave function based on the Bethe ansatz solution is newly
proposed, where the spin-charge separation is realized, and a long-range
correlation factor of Jastrow-type is included. In most regions of the phase
diagram, this wave function provides an excellent description of the
ground-state properties characterized as a Tomonaga-Luttinger liquid; Both of
the amplitude and exponent of correlation functions are correctly reproduced.
For the spin-gap phase, another trial state of correlated singlet pairs with a
Jastrow factor is introduced. This wave function shows generalized Luther-Emery
liquid behavior, exhibiting enhanced superconducting correlations and
exponential decay of the spin correlation function. Using these two variational
wave functions, the whole phase diagram is determined. In addition, relations
between the correlation exponent and variational parameters in the trial
functions are derived.Comment: REVTeX 3.0, 27 pages. 7 figures available upon request
([email protected]). To be published in Phys. Rev. B 5
Charge and Spin Transport in Magnetic Tunnel Junctions: Microscopic Theory
We study the charge and spin currents passing through a magnetic tunnel
junction (MTJ) on the basis of a tight-binding model. The currents are
evaluated perturbatively with respect to the tunnel Hamiltonian. The charge
current has the form , where and denote the directions of
the magnetization in the free layer and fixed layer, respectively. The constant
vanishes when one or both layers are insulators, {while the constant
disappears when both layers are insulators or the same ferromagnets.} The first
term in the expression for charge current represents dissipation driven by the
effective electric field induced by the dynamic magnetization. In addition,
from an investigation of the spin current, we obtain the microscopic expression
for the enhanced Gilbert damping constant . We show that
is proportional to the tunnel conductance and depends on the
bias voltage.Comment: 13 pages, 1 figure, accepted for publication in Journal of the
Physical Society of Japa
Spin Caloritronics
This is a brief overview of the state of the art of spin caloritronics, the
science and technology of controlling heat currents by the electron spin degree
of freedom (and vice versa).Comment: To be published in "Spin Current", edited by S. Maekawa, E. Saitoh,
S. Valenzuela and Y. Kimura, Oxford University Pres
Cytostatic Factor Proteins Are Present in Male Meiotic Cells and β-Nerve Growth Factor Increases Mos Levels in Rat Late Spermatocytes
Background: In co-cultures of pachytene spermatocytes with Sertoli cells, beta-NGF regulates the second meiotic division by blocking secondary spermatocytes in metaphase (metaphase II), and thereby lowers round spermatid formation. In vertebrates, mature oocytes are arrested at metaphase II until fertilization, because of the presence of cytostatic factor (CSF) in their cytoplasm. By analogy, we hypothesized the presence of CSF in male germ cells. Methodology/Principal Findings: We show here, that Mos, Emi2, cyclin E and Cdk2, the four proteins of CSF, and their respective mRNAs, are present in male rat meiotic cells; this was assessed by using Western blotting, immunocytochemistry and reverse transcriptase PCR. We measured the relative cellular levels of Mos, Emi2, Cyclin E and Cdk2 in the meiotic cells by flow cytometry and found that the four proteins increased throughout the first meiotic prophase, reaching their highest levels in middle to late pachytene spermatocytes, then decreased following the meiotic divisions. In co-cultures of pachytene spermatocytes with Sertoli cells, beta-NGF increased the number of metaphases II, while enhancing Mos and Emi2 levels in middle to late pachytene spermatocytes, pachytene spermatocytes in division and secondary spermatocytes. Conclusion/Significance: Our results suggest that CSF is not restricted to the oocyte. In addition, they reinforce the view that NGF, by enhancing Mos in late spermatocytes, is one of the intra-testicular factors which adjusts the number of round spermatids that can be supported by Sertoli cells
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