GLUT1 and GLUT4 glucose transporter expression is highly regulated in muscle and adipose tissue during perinatal life. Here
we have investigated the role of thyroid hormones in the regulation of ...GLUT4 induction and GLUT1 repression associated to
neonatal development. Perinatal hypothyroidism markedly impaired GLUT4 protein induction in heart. This effect was heart specific,
and a greater expression of GLUT4 was detected in brown adipose tissue from neonatal hypothyroid rats compared with controls.
These changes in GLUT4 protein expression were not detected in brown adipose tissue or heart when hypothyroidism was induced
in adult rats. These results indicate that GLUT4 induction during perinatal life is highly sensitive to thyroid hormones in
both heart and adipose tissue. Perinatal hypothyroidism was characterized by decreased cardiac GLUT4 mRNA concentrations.
T3 injection caused a marked increase in cardiac levels of GLUT4 mRNA in hypothyroid neonates. Thus, in 13-day-old hypothyroid
rats, GLUT4 mRNA levels increased 3-fold 1 h after T3 injection. Under these conditions, retinoic acid also caused a rapid
increase in cardiac GLUT4 mRNA levels from hypothyroid neonates. In addition, cardiac levels of GLUT4 protein markedly increased
in fetuses and in neonates 24 h after T3 injection. These findings suggest that a direct effect of thyroid hormones is the
promotion of cardiac GLUT4 gene expression. GLUT1 protein expression was markedly enhanced in brown adipose tissue and heart
during neonatal hypothyroidism as well as in hypothyroidism induced in adult rats. This was concomitant to greater levels
of GLUT1 mRNA in hearts from hypothyroid neonates. Immunofluorescence analysis indicated that cardiomyocytes from hypothyroid
pups contained an enhanced level of GLUT1 protein. Furthermore, T3 injection caused a decrease in cardiac levels of GLUT1
mRNA in hypothyroid neonates. These results indicate that thyroid hormone manipulation leads to inverse regulation of GLUT1
and GLUT4 glucose transporter gene expression in the neonatal heart. We conclude that thyroid hormones play a pivotal role
controlling the transition of glucose transporter carriers from fetal to neonatal levels in heart and brown adipose tissue.
The practice of intratumoral radiocolloid injection for sentinel node biopsy (SNB) allows localization of nonpalpable breast tumors in the same surgical intervention, using the technique known as ...radio-guided occult lesion localization (ROLL).
We present our experience with the combined use of both techniques (SNB and ROLL). A total of 233 patients were retrospectively analyzed: 65 patients underwent ROLL and 168 patients underwent wire-guided localization (control group) as the excision modality. Both groups had comparable pathologic and radiologic features.
Complete excision of the lesion was achieved at the first attempt in only 169 patients. There were no significant differences among groups in surgical margin status (margins were adequate in 80% of ROLL patients vs 69.9% of non-ROLL patients) or in maximum specimen diameter (6.85 cm vs 6.52 cm, respectively).
We conclude that ROLL is an acceptable alternative to wire-guided localization in patients with nonpalpable breast tumors undergoing SNB, leading to easier lesion excision and greater patient comfort.
Mammalian skeletal muscle expresses GLUT-4 and GLUT-1 glucose transporters. Here, we have investigated whether GLUT-1 and
GLUT-4 expression is regulated in muscle by contractile activity. GLUT-1 mRNA ...levels were high in skeletal muscle at days
16 and 17 of fetal life and decreased markedly by days 19 and 21. In contrast, GLUT-4 mRNA levels were clearly detectable
at day 21 of fetal life, and they increased progressively during postnatal life. The timing data for GLUT-4 induction and
GLUT-1 repression suggest that these processes are related to skeletal muscle innervation. GLUT-4 mRNA decreased markedly
in adult rat and rabbit tibialis anterior muscle after severage of peroneal nerve. In contrast, GLUT-1 mRNA levels showed
a 9-fold increase in rat muscle 3 days after denervation. Direct stimulation of rabbit tibialis anterior muscle with extracellular
electrodes protected GLUT-4 mRNA levels against the effect of denervation. This indicates that the repression of GLUT-4 mRNA
associated with denervation is due, at least in part, to electrical activity. Increased contractile activity induced for 24
h by indirect electrical stimulation at low frequency caused a marked and specific increase in GLUT-1 mRNA levels in rabbit
tibialis anterior muscle. Our results indicate that (a) innervation-dependent basal contractile activity regulates in an inverse
manner the expression of GLUT-1 and GLUT-4 in skeletal muscle, and (b) enhanced contractile activity stimulates GLUT-1 expression
in the absence of modifications to GLUT-4 expression. This suggests the existence of different factors which depend on contractile
activity and which control GLUT-1 and GLUT-4 glucose transporter expression in skeletal muscle.
From a managerial point of view, the more effcient, simple, and parameter-free (ESP) an algorithm is, the more likely it will be used in practice for solving real-life problems. Following this ...principle, an ESP algorithm for solving the Permutation Flowshop Sequencing Problem (PFSP) is proposed in this article. Using an Iterated Local Search (ILS) framework, the so-called ILS-ESP algorithm is able to compete in performance with other well-known ILS-based approaches, which are considered among the most effcient algorithms for the PFSP. However, while other similar approaches still employ several parameters that can affect their performance if not properly chosen, our algorithm does not require any particular fine-tuning process since it uses basic "common sense" rules for the local search, perturbation, and acceptance criterion stages of the ILS metaheuristic. Our approach defines a new operator for the ILS perturbation process, a new acceptance criterion based on extremely simple and transparent rules, and a biased randomization process of the initial solution to randomly generate different alternative initial solutions of similar quality -which is attained by applying a biased randomization to a classical PFSP heuristic. This diversification of the initial solution aims at avoiding poorly designed starting points and, thus, allows the methodology to take advantage of current trends in parallel and distributed computing. A set of extensive tests, based on literature benchmarks, has been carried out in order to validate our algorithm and compare it against other approaches. These tests show that our parameter-free algorithm is able to compete with state-of-the-art metaheuristics for the PFSP. Also, the experiments show that, when using parallel computing, it is possible to improve the top ILS-based metaheuristic by just incorporating to it our biased randomization process with a high-quality pseudo-random number generator.
From a managerial point of view, the more efficient, simple, and parameter-free (ESP) an algorithm is, the more likely it will be used in practice for solving real-life problems. Following this ...principle, an ESP algorithm for solving the Permutation Flowshop Sequencing Problem (PFSP) is proposed in this article. Using an Iterated Local Search (ILS) framework, the so-called ILS-ESP algorithm is able to compete in performance with other well-known ILS-based approaches, which are considered among the most efficient algorithms for the PFSP. However, while other similar approaches still employ several parameters that can affect their performance if not properly chosen, our algorithm does not require any particular fine-tuning process since it uses basic ‘common sense’ rules for the local search, perturbation, and acceptance criterion stages of the ILS metaheuristic. Our approach defines a new operator for the ILS perturbation process, a new acceptance criterion based on extremely simple and transparent rules, and a biased randomization process of the initial solution to randomly generate different alternative initial solutions of similar quality -which is attained by applying a biased randomization to a classical PFSP heuristic. This diversification of the initial solution aims at avoiding poorly designed starting points and, thus, allows the methodology to take advantage of current trends in parallel and distributed computing. A set of extensive tests, based on literature benchmarks, has been carried out in order to validate our algorithm and compare it against other approaches. These tests show that our parameter-free algorithm is able to compete with state-of-the-art metaheuristics for the PFSP. Also, the experiments show that, when using parallel computing, it is possible to improve the top ILS-based metaheuristic by just incorporating to it our biased randomization process with a high-quality pseudo-random number generator.
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