Electromagnetic levitation containerless processing of metallic materials in microgravity: rapid solidification.

Space levitation processing allows researchers to conduct benchmark tests in an effort to understand the physical phenomena involved in rapid solidification processing, including alloy thermodynamics, nucleation and growth, heat and mass transfer, solid/liquid interface dynamics, macro- and microstructural evolution, and defect formation. Supported by ground-based investigations, a major thrust is to develop and refine robust computational tools based on theoretical and applied approaches. This work is accomplished in conjunction with experiments designed for precise model validation with application to a broad range of industrial processes.

[Vascular surgery in old people]. / Gefäßchirurgie bei alten Menschen.

The age pyramid in Germany is upside down. According to the Federal Statistical Office this development will continue in the coming years, which presents a challenge for surgeons to surgically treat increasingly more and increasingly older people. Particularly in vascular surgery, which is a surgery of old people, this fact represents a special challenge. The frailty of old people is, among other things, due to a series of comorbidities, which must be taken into consideration within the framework of surgical treatment. They can have an important influence on the perioperative planning, the operation, the postoperative treatment and the outcome of the patient. This treatment planning becomes more and more challenging, because due to the progress in endovascular surgery there will soon be no limits to what is feasible; however, the question arises whether the feasible is also reasonable? Within the scope of this article the authors try to give answers to the treatment of old patients in vascular surgery and to find strategies for planning and to establish an individualized optimal treatment.

Care pathways in atopic dermatitis: a retrospective population-based cohort study.

BACKGROUND: Atopic dermatitis (AD) is a complex disease with variations in severity and healthcare utilization. Examining patient pathways through analyses of longitudinal patient data provides an opportunity to describe real-world clinical patient care and evaluate healthcare access and treatment. OBJECTIVE: To describe longitudinal care pathways including health care management, treatment patterns and disease progression (by proxy measures) in patients with AD. MATERIALS AND METHODS: This was a longitudinal observational study, which used linked data from national and regional healthcare registers in Sweden. Patients with AD were identified through diagnosis in primary or secondary care or by dispensed medications. Descriptive statistics for number of healthcare visits, type of dispensed drug class, rate of - and time to - referral to secondary care and treatment escalation were calculated. RESULTS: A total of 341 866 patients with AD distributed as 197 959 paediatric (age < 12), 36 133 adolescent (age ≥ 12- < 18) and 107 774 adult (age ≥ 18) patients were included in this study. Healthcare visits to primary and secondary care and dispensation of AD-indicated treatments were more common during the year in which managed AD care was initiated. Topical corticosteroids (TCSs) and emollients were the most frequently used treatments across all age cohorts while systemic treatment was uncommon in all age cohorts. Among patients who initiated treatment with TCSs, 18.2% escalated to TCSs with higher potency following the start of managed AD care. CONCLUSIONS: We found that healthcare contacts and use of AD-indicated treatments were concentrated in the year during which managed AD care was initiated and decreased significantly thereafter. Since a significant proportion of patients with AD have flares and persistent AD, our results suggest that patients with AD may be monitored infrequently and are undertreated. There is a need to inform practitioners about adequate treatment options to provide individualized care, in particular for patients with persistent severe AD.

CRISTAPRESS: an optical cell for structure development in high-pressure crystallization.

An original optical high-pressure cell, named CRISTAPRESS, has been especially designed to investigate phase transitions of complex liquids, i.e., polymers, polymer blends, nano-composites, etc. The design of the cell is based on the optical properties of morphological entities through in situ light depolarizing microscopic observations. Pressure up to 200 MPa with a fine temperature control up to 300 °C can be applied. A striking advantage of this cell is the possibility to select the pressure transmitting medium that can be water, silicone oil, a fluid in the supercritical state, etc. The potential of the novel technique was demonstrated by carrying out time-resolved measurements during polymer crystallization induced by water pressure. These preliminary experimental investigations permit to discriminate the role of the barometric and thermal histories on the kinetics of polymer growth, as well as on the subsequent morphologies. It should lead to new reliable crystallization kinetics models.

[First-line radiosurgery of brain metastases. Interest and results of reduced dose]. / Irradiation stéréotaxique de première intention des métastases cérébrales. Intérêt et résultats d'une réduction de la dose délivrée.

BACKGROUND: The minimal radiosurgical dose required to control cerebral metastases remains unknown. The aim of this study was to test whether a lower peripheral dose than usually delivered could effectively control these lesions or not. PATIENTS AND METHODS: One hundred and eighty patients presenting 356 lesions were give first-line radiosurgery between 1995 and 2001 in Pitié-Salpêtrière hospital using a 10 MV LINAC. Mean age was 59 years, sex-ratio was 1.65, mean KI was 70. The lung was the most frequent primary site (n=85), followed by melanoma (n=29), kidney (n=21), digestive tract (n=14), breast (n=11), and others (n=20). Seventy-six percent of the patients presented 1 or 2 lesions. Mean tumor Volume was 5.5 cm3. Mean peripheral dose was 14.8Gy, mean isocenter dose was 21.6Gy. RESULTS: Median survival was 7.6 months, local control rate was 90% at 6 months, 76% at 1 Year and 70% at 2 years. Median "neurological disease free" survival was 15 months. Multivariate analysis demonstrated the influence of two parameters on survival: number of lesions (p=0.001) and KI (p=0.04). The only parameter significantly correlated with disease-free survival was the number of isocenters (p=0.005). Morbidity (grade 2 RTOG) was 7.2% with no perimortality. CONCLUSIONS: Low peripheral doses delivered by radiosurgery may control brain metastases with the same efficacy and fewer side-effects as the doses usually reported in the literature.

Aldosterone, a new appreciation of its role in heart failure.

Understanding of the role, triggers, and impact of the renin-angiotensin-aldosterone system in cardiovascular disease has significantly broadened. In recent years substantial discoveries have been made regarding the pathophysiology of heart failure, particularly in the area of neurohormonal activation. New interest in therapy with aldosterone antagonists was stimulated by results of a 2-year study of 1663 patients with heart failure that showed a 30% relative risk reduction of death among patients given a subhemodynamic dosage of spironolactone, a nonselective aldosterone antagonist, compared with placebo, in addition to standard therapy of diuretics, angiotensin-converting enzyme inhibitors, beta-blockers, and digitalis.

Deletion of the S3-S4 linker in the Shaker potassium channel reveals two quenching groups near the outside of S4.

When attached outside the voltage-sensing S4 segment of the Shaker potassium channel, the fluorescent probe tetramethylrhodamine (TMRM) undergoes voltage-dependent fluorescence changes (DeltaF) due to differential interaction with a pH-titratable external protein-lined vestibule (Cha, A., and F. Bezanilla. 1998. J. Gen. Physiol. 112:391-408.). We attached TMRM at the same sites [corresponding to M356C and A359C in the wild-type (wt) channel] in a deletion mutant of Shaker where all but the five amino acids closest to S4 had been removed from the S3-S4 linker. In the deletion mutant, the maximal DeltaF/F seen was diminished 10-fold, and the DeltaF at M356C became pH independent, suggesting that the protein-lined vestibule is made up in large part by the S3-S4 linker. The residual DeltaF showed that the probe still interacted with two putative quenching groups near the S4 segment. One group was detected by M356C-TMRM (located outside of S3 in the deletion mutant) and reported on deactivation gating charge movement when applying hyperpolarizing voltage steps from a holding potential of 0 mV. During activating voltage steps from a holding potential of -90 mV, the fluorescence lagged considerably behind the movement of gating charge over a range of potentials. Another putative quenching group was seen by probes attached closer to the S4 and caused a DeltaF at extreme hyperpolarizations (more negative than -90 mV) only. A signal from the interaction with this group in the wt S3-S4 linker channel (at L361C) correlated with gating charge moving in the hyperpolarized part of the Q-V curve. Probe attached at A359C in the deletion mutant and at L361C in wt channel showed a biphasic DeltaF as the probe oscillated between the two groups, revealing that there is a transient state of the voltage sensor in between, where the probe has maximal fluorescence. We conclude that the voltage sensor undergoes two distinct conformational changes as seen from probes attached outside the S4 segment.

In vitro and in vivo activity of protein kinase C inhibitor chelerythrine chloride induces tumor cell toxicity and growth delay in vivo.

Although clonogenic or divisional death is the main mechanism by which DNA-damaging agents demonstrate antitumor activity, recent data indicate that strategies specifically designed to trigger apoptosis may also prove to be useful antitumor agents. Protein kinase C (PKC) isoenzymes are involved in the regulation of cell proliferation, differentiation, and survival. Whereas pharmacological inhibition of PKC activity triggers apoptosis in most mammalian cells, cell line and tissue differences in sensitivities to these inhibitors remain. Whereas PKC inhibitors have potential as antitumor agents, issue of kinase specificity and solubility have remained obstacles to their clinical use. In this report, we investigated the antitumor activity of the PKC inhibitor chelerythrine chloride (chelerythrine), a selective inhibitor of group A and B PKC isoforms. Chelerythrine exhibited cytotoxic activity against nine human tumor cell lines tested in vitro. On the basis of the finding that radioresistant and chemoresistant squamous cell carcinoma lines (HNSCC) undergo apoptosis rapidly after treatment with chelerythrine in vitro, we assessed the effects of this agent on p53-deficient SQ-20B HNSCC cells in vivo. The results demonstrate that chelerythrine treatment of nude mice bearing SQ-20B is associated with significant tumor growth delay. Significantly, treatment with chelerythrine resulted in minimal toxicity. These findings demonstrate a potential for chelerythrine as an antitumor drug against squamous cell carcinoma.

Beta blockers and lactation: an update.

Beta-adrenergic antagonists are one of the most commonly used class of agents in the treatment of hypertension. They have also demonstrated utility in the treatment of angina pectoris and certain arrhythmias and for the reduction in mortality following a myocardial infarction. The use of this class of agents creates the potential for beta-blocker exposure among lactating women. This review focuses on the most up-to-date data regarding the more common agents--metoprolol, atenolol, propranolol, carvedilol, nadolol, sotalol, and betaxolol--and their safety in lactating women.

Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) and lactation: an update.

Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are commonly used for the treatment of hypertension. ACEIs have been promoted as first-line therapy for selected patients with chronic hypertension and for the prevention of diabetic nephropathy, thus creating the potential for frequent ACEI exposure among women of childbearing age. ARBs are the most recent addition to the available options for antihypertensive agents. This review specifically focuses on the most up-to-date information regarding these newer antihypertensives with regard to lactation.

Calcium channel antagonists and lactation: an update.

Approximately 14% of women of age 20-54 years old have hypertension. For those women who are on medication for hypertension and are pregnant, this poses potential problems. In many cases, antihypertensive agents may be continued in women with chronic hypertension if taken prior to pregnancy. This article discusses the antihypertensive class, calcium channel antagonists, with regard to their physiochemical properties and lactation.

Voltage sensors in domains III and IV, but not I and II, are immobilized by Na+ channel fast inactivation.

Using site-directed fluorescent labeling, we examined conformational changes in the S4 segment of each domain of the human skeletal muscle sodium channel (hSkM1). The fluorescence signals from S4 segments in domains I and II follow activation and are unaffected as fast inactivation settles. In contrast, the fluorescence signals from S4 segments in domains III and IV show kinetic components during activation and deactivation that correlate with fast inactivation and charge immobilization. These results indicate that in hSkM1, the S4 segments in domains III and IV are responsible for voltage-sensitive conformational changes linked to fast inactivation and are immobilized by fast inactivation, while the S4 segments in domains I and II are unaffected by fast inactivation.

Full and partial 5-HT1A receptor agonists disrupt learning and performance in rats.

As a means of characterizing the role of 5-hydroxytryptamine (5-HT1A) receptors in learning, a full 5-HT1A receptor agonist, 8-hydroxy-dipropylaminotetralin (8-OH-DPAT), was administered both alone and in combination with two partial agonists (buspirone and 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190)) and a 5-HT1A receptor antagonist (p-MPPI) to rats responding under a multiple schedule of repeated acquisition and performance of response sequences. In addition, the effects of another 5-HT1A receptor agonist, (LY228729), were also studied under this same procedure. When administered alone, both 8-OH-DPAT (0.1-3. 2 mg/kg) and LY228729 (0.32-3.2 mg/kg) dose dependently decreased overall response rate and increased the percentage of errors in the acquisition and performance components. At the doses of each drug tested, both buspirone (0.32 or 1 mg/kg) and NAN-190 (1 or 3.2 mg/kg) also decreased overall response rate and increased the percentage of errors. However, the effects of these drugs differed across behavioral components and dependent measures. The effects of buspirone and NAN-190 on rate and accuracy were also different when they were administered in combination with 8-OH-DPAT. In contrast, p-MPPI (3.2 or 10 mg/kg) had little or no effect when administered alone and antagonized the effects of 8-OH-DPAT; shifting the dose-effect curves for both response rate and the percentage of errors in both components to the right. Taken together, these results indicate that complex behaviors in rats are sensitive to disruption by drugs with both full and partial 5-HT1A receptor agonist properties, and that the effects of partial 5-HT1A receptor agonists on learning may be different depending on their efficacy at pre- and postsynaptic 5-HT1A receptors.

Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy.

Voltage-gated ion channels are transmembrane proteins that are essential for nerve impulses and regulate ion flow across cell membranes in response to changes in membrane potential. They are made up of four homologous domains or subunits, each of which contains six transmembrane segments. Studies of potassium channels have shown that the second (S2) and fourth (S4) segments contain several charged residues, which sense changes in voltage and form part of the voltage sensor. Although these regions clearly undergo conformational changes in response to voltage, little is known about the nature of these changes because voltage-dependent distance changes have not been measured. Here we use lanthanide-based resonance energy transfer to measure distances between Shaker potassium channel subunits at specific residues. Voltage-dependent distance changes of up to 3.2 A were measured at several sites near the S4 segment. These movements directly correlated with electrical measurements of the voltage sensor, establishing the link between physical changes and electrical charge movement. Measured distance changes suggest that the region associated with the S4 segment undergoes a rotation and possible tilt, rather than a large transmembrane movement, in response to voltage. These results demonstrate the first in situ measurement of atomic scale movement in a trans-membrane protein.

Structural implications of fluorescence quenching in the Shaker K+ channel.

When attached to specific sites near the S4 segment of the nonconducting (W434F) Shaker potassium channel, the fluorescent probe tetramethylrhodamine maleimide undergoes voltage-dependent changes in intensity that correlate with the movement of the voltage sensor (Mannuzzu, L.M., M.M. Moronne, and E.Y. Isacoff. 1996. Science. 271:213-216; Cha, A., and F. Bezanilla. 1997. Neuron. 19:1127-1140). The characteristics of this voltage-dependent fluorescence quenching are different in a conducting version of the channel with a different pore substitution (T449Y). Blocking the pore of the T449Y construct with either tetraethylammonium or agitoxin removes a fluorescence component that correlates with the voltage dependence but not the kinetics of ionic activation. This pore-mediated modulation of the fluorescence quenching near the S4 segment suggests that the fluorophore is affected by the state of the external pore. In addition, this modulation may reflect conformational changes associated with channel opening that are prevented by tetraethylammonium or agitoxin. Studies of pH titration, collisional quenchers, and anisotropy indicate that fluorophores attached to residues near the S4 segment are constrained by a nearby region of protein. The mechanism of fluorescence quenching near the S4 segment does not involve either reorientation of the fluorophore or a voltage-dependent excitation shift and is different from the quenching mechanism observed at a site near the S2 segment. Taken together, these results suggest that the extracellular portion of the S4 segment resides in an aqueous protein vestibule and is influenced by the state of the external pore.

Modulation of apoptotic response of a radiation-resistant human carcinoma by Pseudomonas exotoxin-chimeric protein.

Strategies to sensitize human tumors that are resistant to apoptosis have been clinically unsuccessful. We demonstrate that a structurally modified chimeric Pseudomonas exotoxin, PEdelta53L/TGF-alpha/KDEL, with binding specificity for the epidermal growth factor receptor, markedly enhances sensitivity of human xenografts to radiation killing. Exposure to PEdelta53L/TGF-alpha/KDEL decreases the apoptotic threshold through protein synthesis inhibition and simultaneous production of ceramide in tumor cells that lack functional p53 protein. In contrast, no increase in local or systemic toxicity was observed with the chimeric toxin and radiation. We conclude that biochemical targeting of the chimeric toxin and physical targeting of ionizing radiation may increase the therapeutic ratio in the treatment of human cancers with alterations of p53 expression. This strategy offers a high therapeutic potential for Pseudomonas exotoxin A chimeric proteins and irradiation.

Characterizing voltage-dependent conformational changes in the Shaker K+ channel with fluorescence.

We examined voltage-dependent conformational changes in three specific regions of the Shaker potassium channel with site-directed fluorescent labeling: the fourth transmembrane segment (S4), the second transmembrane segment (S2), and the putative pore region. The fluorescence changes displayed distinctive properties that correlate with gating, activation, and slow inactivation of the channel. The fluorescence signals measured near the S2 and S4 segments suggest that the S2 segment may undergo voltage-sensitive conformational changes that precede those in the S4 segment. In contrast, fluorescence changes in the pore correlated with the voltage dependence and time course of ionic activation and slow inactivation. Spectroscopy indicated that the mechanism of fluorescence change involves voltage-dependent quenching of the probe in an aqueous environment by other parts of the protein.

The use of magnets in the comprehensive treatment of congenital partial anodontia: a case report.

This case report describes the treatment of an adult patient with a combination of fixed and removable prosthodontics. The treatment involved increasing the patient's vertical dimension of occlusion, placing two osseointegrated implants, making six surveyed crowns, fabricating a maxillary partial denture, and using magnets to help retain the mandibular partial denture. The clinical steps for using a type of intraoral magnet are described.