Optimized sound diffusers based on sonic crystals using a multiobjective evolutionary algorithm

Sonic crystals have been demonstrated to be good candidates to substitute for conventional diffusers in order to overcome the need for extremely thick structures when low frequencies have to be scattered, however, their performance is limited to a narrow band. In this work, multiobjective evolutionary algorithms are used to extend the bandwidth to the whole low frequency range. The results show that diffusion can be significantly increased. Several cost functions are considered in the paper, on the one hand to illustrate the flexibility of the optimization and on the other hand to demonstrate the problems associated with the use of certain cost functions. A study of the robustness of the optimized diffusers is also presented, introducing a parameter that can help to choose among the best candidates. Finally, the advantages of the use of multiobjective optimization in comparison with conventional optimizations are discussed.

Neutrino and axion bounds from the globular cluster M5 (NGC 5904)

The red-giant branch (RGB) in globular clusters is extended to larger brightness if the degenerate helium core loses too much energy in "dark channels." Based on a large set of archival observations, we provide high-precision photometry for the Galactic globular cluster M5 (NGC 5904), allowing for a detailed comparison between the observed tip of the RGB with predictions based on contemporary stellar evolution theory. In particular, we derive 95% confidence limits of g(ae)<4.3×10(-13) on the axion-electron coupling and μ(ν)<4.5×10(-12)μ(B) (Bohr magneton μ(B)=e/2m(e)) on a neutrino dipole moment, based on a detailed analysis of statistical and systematic uncertainties. The cluster distance is the single largest source of uncertainty and can be improved in the future.

Sound diffusers based on sonic crystals

A sound diffuser is proposed based on sonic crystals, structures formed by a periodic distribution of cylindrical scatterers in a host medium, which is usually air. The diffuser is a so-called biperiodic structure, as formed by two arrays of sonic crystals with slightly different periodicities. Large diffusivity at low frequencies is achieved when the typical scale of the blocks is much larger than the periodicity of the crystals, determined by its lattice constant. An interpretation of the low frequency behavior of the diffuser is given in the homogenization limit in terms of multiple reflections and interference between the fields scattered by the different blocks. It is also shown that sonic crystal based diffusers enhance time spreading in comparison with other conventional diffusers.

Neuroimage in Psychiatry - What Can we See?

In the 20th century, scientists attempted to limitate the workings of the mind onto the brain by detailing its anatomy and physiology. The task of localizing function, however, has proven to be very difficult than initially presumed, with almoust all regions of the brain subserving a variety of processes and having only loose coupling of structure and function. As we know, the majority of neuropsychological tests and the brain capacities they tap lack brain regional specificity. This is a complex and sophisticated problem, that gets much worse in the brain that is compounded significantly by damage or disease. However, in the past two decades, neuroimaging has rekindled and renewed enthusiasm for unraveling brain function. Recent studies of cerebral image show “in vivo” what had already been proven in the laboratory: there are multiples neuroquimical changes in cortical and subcortical areas of the brain in psychiatric patients.

Amongst the many techniques and technologies that have been developed, functional magnetic resonance imaging (fMRI) has proven to be one of the most exciting and perhaps the most used. It has permitted unprecedented access to the living brain. The authors propose to do a brief review on the late descoverys and studys that have been done with neuroimage.

[Brachial plexus block for minimally invasive parathyroidectomy: report of 3 cases]

The brachial plexus block, either deep or superficial, is one of the anesthetic techniques used in parathyroidectomy. The block is easy to perform and has few hemodynamic side effects. Surgery can be carried out in an awake patient. We describe 3 cases of patients with primary hyperparathyroidism (parathyroid adenoma) who underwent unilateral minimally invasive parathyroidectomy under regional anesthesia and sedation with 2 mg of midazolam plus remifentanil at dosages ranging from 0.6 to 0.1 microg kg(-1) min(-1). To provide a deep cervical block, we administered 15 mL of 0.75% ropivacaine. For a superficial block, 15 mL of 0.2% ropivacaine was used. The procedure could be completed in all 3 patients under regional anesthesia. The latency time for the block ranged from 21 to 30 minutes, and remifentanil dosages from 0.05 to 0.09 microg kg(-1) min(-1) were administered for procedures that lasted 30 to 45 minutes. No patient required postoperative opioids or antiemetics, although a local anesthetic had to be used at the moment of incision for 1 patient. All 3 patients were discharged the same day. We wish to underline the utility of the brachial plexus block for parathyroid surgery. The technique is easy to perform, safe, and effective; as a result, surgery can be carried out on an outpatient basis.

Excitability in a nonlinear magnetoacoustic resonator

We report a nonlinear acoustic system displaying excitability. The considered system is a magnetostrictive material where acoustic waves are parametrically generated. For a set of parameters, the system presents homoclinic and heteroclinic dynamics, whose boundaries define an excitability domain. The excitable behavior is characterized by analyzing the response of the system to different external stimuli. Single-spiking and bursting regimes have been identified. All these neuronlike properties are here predicted to occur in magnetostrictive materials, which are the basis of many smart systems and applications.

Self-pulsing dynamics of ultrasound in a magnetoacoustic resonator

A theoretical model of parametric magnetostrictive generation of ultrasound is considered, taking into account magnetic and magnetoacoustic nonlinearities. The stability and temporal dynamics of the system is analyzed with standard techniques revealing that, for a given set of parameters, the model presents a homoclinic or saddle-loop bifurcation, which predicts that the ultrasound is emitted in the form of pulses or spikes with arbitrarily low frequency.

[Hafnia alvei in a rare case of severe pneumonia in a postanesthesia recovery unit]

An 85-year-old man with a history of moderate chronic obstructive pulmonary disease in treatment with anticholinergic drugs was admitted to the recovery unit for postoperative monitoring after right inguinal herniorrhaphy surgery and removal of a strangulated intestinal section. On the third day after surgery the patient developed radiographic signs consistent with pneumonia and required mechanical ventilation. Two blood cultures and a respiratory secretion sample grew a microorganism identified as Hafnia alvei. H. alvei is a gram-negative bacillus that colonizes the digestive tract of humans and animals and in immunodepressed patients it can colonize the mouth and pharynx. Isolation of H. alvei is described in the literature on pediatric patients and those with a history of immune deficiency or chronic disease. Infection has a severe impact on general health. We report a rare and interesting case of pneumonia and bacteremia from H. alvei infection acquired by an immunocompetent patient soon after arrival in the postoperative recovery unit. The patient died of the infection.

University of Wisconsin solution increases hyperpolarizing mechanisms in response to bradykinin

BACKGROUND

The aim of this study was to determine the effect of University of Wisconsin solution (UWS) incubation on bradykinin-induced vasodilation.

METHODS

Porcine coronary arteries were incubated in Krebs-Henseleit solution (KHS) or UWS at 4 degrees C for 20 hours. Endothelium-dependent relaxation to bradykinin and endothelium-independent relaxation to nitric oxide were tested after U46619 or KCl pre-contraction. Nitric oxide synthase activity and protein expression was determined by [3H]-L-citrulline formation and western blot analysis, respectively.

RESULTS

The relaxation to bradykinin (0.1 to 300 nmol/liter) after U46619 (30 to 300 nmol/liter) pre-contraction was similar with both KHS and UWS pre-incubation; however, it was reduced after KCl pre-contraction (15 to 20 mmol/liter), this reduction being greater after UWS incubation. The inhibitory effect of N(G)-nitro-L-arginine methylester (0.1 mmol/liter) on bradykinin-induced relaxation was lower in UWS- than KHS-incubated segments after U46619 pre-contraction, but similar after KCl pre-contraction; however, the inhibitory effect of 0.5 mmol/liter ouabain was unaffected. Tetraethylammonium (5 mmol/liter) reduced the response to bradykinin more strongly after UWS pre-incubation. UWS did not modify relaxation to nitric oxide (0.1 to 30 micromol/liter) in pre-incubated UWS or KHS segments. UWS failed to modify both total nitric oxide synthase activity and endothelial nitric oxide synthase expression.

CONCLUSIONS

UWS incubation decreased nitric oxide participation and increased the hyperpolarizing mechanisms produced by bradykinin.

Relation between conditioned stimulus-elicit responses and unconditioned response diminution in long-interval human heart-rate classical conditioning

Previous research on electrodermal conditioning suggests that the conditioned diminution of the unconditioned response (UR) has an associative basis. The aim of this experiment was to test whether this phenomenon also occurs in heart rate (HR) classical conditioning. For this purpose, a differential classical conditioning was performed. The conditioned stimuli (CSs) were geometrical shapes (the CS+ was a square and the CS- was a triangle) displayed on a computer screen and a burst of white noise was used as unconditioned stimulus (US). For analysis of the conditioned response (CR) components, an interval between CS+ and US of 8 seconds was used. After the acquisition phase, participants were tested using trials with the US preceded either by a CS+, a CS-, or a neutral stimulus (a circle). The results showed conditioned diminution of the UR and suggest that the second heart rate deceleration component (D2) is responsible for the occurrence of this phenomenon.

Cell volume and ionic transport systems after cold preservation of coronary endothelial cells

BACKGROUND

Hypothermia-induced changes in cell volume and ionic transport systems of coronary endothelial cells may play a role in the development of coronary artery disease in cardiac transplant recipients.

METHODS

Coronary endothelial cells were incubated in University of Wisconsin solution or culture control medium for up to 48 hours at 4 degrees C. Parallel control cultures were incubated at 37 degrees C. Na/K-ATPase and Na/K/Cl cotransport activities were determined as ouabain- and furosemide-sensitive 86Rb+ uptake, respectively. Cell volume changes and cell death were analyzed by a FACScan flow cytometer and the release of lactate dehydrogenase, respectively.

RESULTS

Coronary endothelial cells stored in University of Wisconsin solution up to 6 hours showed an increased Na/K-ATPase activity compared to control cells, whereas no changes were observed in Na/K/Cl cotransport activity or cell volume. Long-term preservation (24 and 48 hours) was associated with a partial loss of cell viability, as demonstrated by lactate dehydrogenase release, and dramatic alterations in ionic transport system activities.

CONCLUSIONS

University of Wisconsin solution seems to prevent coronary endothelial cells Na/K/Cl cotransport activity changes during cold preservation, which could alter cell volume regulation and cause cell injury.

Hypothermic storage of coronary endothelial cells reduces nitric oxide synthase activity and expression

Preservation with University of Wisconsin (UW) solution has been implicated in coronary artery endothelial damage and loss of endothelium-dependent vasodilatation. Therefore, the objective of this study was to investigate the effect of this solution on basal nitric oxide (NO) release from porcine coronary endothelial cells (CEC). Cultures were exposed to cold (4 degrees C) storage in UW solution for 6, 8 and 12 h. Parallel cultures were incubated with control medium at 37 degrees C. After treatment, NO release was evaluated by nitrite production, a stable metabolite of NO. Activity of the constitutive endothelial nitric oxide synthase (eNOS) was measured by the conversion [3H]-l-arginine to [3H]-l-citrulline and eNOS protein expression by Western blotting. Nitrite production by control cells was augmented with increasing times of incubation, whereas no change was observed in those cultures preserved with UW solution. Activity of eNOS was significantly decreased compared to the respective control group by cold storage of cells for longer periods than 6 h. Such decrease was correlated with a diminished eNOS protein expression in CEC preserved with UW solution after 8- and 12-h storage. These results suggest that prolonged hypothermic storage of CEC with UW solution does not preserve basal NO release because of a certain loss of eNOS protein, which may contribute to the reported injury of heart transplants after long-term preservation.

Nitric oxide synthase induction by ouabain in vascular smooth muscle cells from normotensive and hypertensive rats

OBJECTIVE

To investigate the effect of ouabain on inducible nitric oxide synthase (iNOS) activity and expression in cytokine-stimulated vascular smooth muscle cells (VSMC) from normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR).

METHODS

VSMC were treated for 24 h and afterwards, nitric oxide (NO) release was determined by the production of nitrite, a stable metabolite of NO. Activity of iNOS was measured by the conversion of [3H]-L-arginine to [3H]-L-citrulline and iNOS protein expression by Western blotting.

RESULTS

Ouabain (0.01-1 mmol/l) further enhanced interleukin-1beta (II-1beta)-induced nitrite production by WKY and SHR VSMC, although a more pronounced effect was observed in SHR cells (maximum response 52.1 +/- 5.2 and 71.2 +/- 6.4% of 11-1beta effect in WKY and SHR cells, respectively). Such response on NO release was mimicked by the calcium ionophore A 23187 (0.01-1 micromol/l) and abolished by the voltage-operated calcium channels (VOCC) nifedipine (0.1 micromol/l). Expression of iNOS showed that ouabain increased the synthesis of the enzyme in WKY and SHR VSMC stimulated with II-1beta, and this effect was higher in SHR cells. The increased iNOS expression was significantly reduced by nifedipine.

CONCLUSIONS

Ouabain stimulation of iNOS expression and activity in II-1beta-stimulated VSMCs from WKY rats and SHR seems to be related to increased intracellular calcium influx through VOCC. The more pronounced effect observed in SHR VSMC could be explained by an altered calcium entry in the hypertensive strain.

Spectromicroscopy of boron in human glioblastomas following administration of Na2B12H11SH

Boron neutron capture therapy (BNCT) is an experimental, binary treatment for brain cancer which requires as the first step that tumor tissue is targeted with a boron-10 containing compound. Subsequent exposure to a thermal neutron flux results in destructive, short range nuclear reaction within 10 microm of the boron compound. The success of the therapy requires than the BNCT agents be well localized in tumor, rather than healthy tissue. The MEPHISTO spectromicroscope, which performs microchemical analysis by x-ray absorption near edge structure (XANES) spectroscopy from microscopic areas, has been used to study the distribution of trace quantities of boron in human brain cancer tissues surgically removed from patients first administered with the compound Na2B12H11SH (BSH). The interpretation of XANES spectra is complicated by interference from physiologically present sulfur and phosphorus, which contribute structure in the same energy range as boron. We addressed this problem with the present extensive set of spectra from S, B, and P in relevant compounds. We demonstrate that a linear combination of sulfate, phosphate and BSH XANES can be used to reproduce the spectra acquired on boron-treated human brain tumor tissues. We analyzed human glioblastoma tissue from two patients administered and one not administered with BSH. As well as weak signals attributed to BSH, x-ray absorption spectra acquired from tissue samples detected boron in a reduced chemical state with respect to boron in BSH. This chemical state was characterized by a sharp absorption peak at 188.3 eV. Complementary studies on BSH reference samples were not able to reproduce this chemical state of boron, indicating that it is not an artifact produced during sample preparation or x-ray exposure. These data demonstrate that the chemical state of BSH may be altered by in vivo metabolism.

Different sensitivity of isoprenaline-induced responses in ventricular muscle to sodium nitroprusside in normotensive and spontaneously hypertensive rats

1. The aim of the present work was to study the possible modulatory role of nitric oxide (NO) on the positive inotropic effect induced by the beta-adrenoceptor agonist isoprenaline in myocardial contractility, and whether this modulation is altered by hypertension. 2. The study was performed using right ventricular strips from the hearts of 6-month-old male Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The contractile force of electrically-stimulated ventricular strips was measured by a force-displacement transducer. 3. Isoprenaline (from 10 nmol l(-1) to 10 micromol l(-1)) induced a concentration-dependent increase in cardiac contractility in strips from both rat strains. This positive inotropic effect to isoprenaline was reduced by the NO donor sodium nitroprusside (SNP, 0.1 mmol l(-1)) in muscles from WKY rats and slightly increased in those from SHR. The SNP-induced increase in strips from SHR was abolished by superoxide dismutase (100 U ml(-1)). 4. N(G)-nitro-arginine-methyl ester (L-NAME, 0.1 mmol l(-1)) and 1H-[1,2,4]oxadiazolo[4,3]-quinoxalin-1-one (ODQ, 10 micromol l(-1)), respective inhibitors of NO synthase and guanylate cyclase, increased the response to isoprenaline in muscles from WKY rats, whereas it was unaltered in strips from SHR. 5. In strips from WKY rats, the combination of ODQ and SNP produced an increase in the response elicited by isoprenaline, which was similar to that observed with ODQ or L-NAME. 8-Br-cyclicGMP (8-Br-cGMP, 0.1 mmol l(-1)), a permeable and structural cGMP analogue, decreased the effect induced by isoprenaline only in muscles from WKY rats. 6. These results suggest that the positive inotropic response to isoprenaline in ventricular strips from WKY rats is negatively modulated by NO, and positively by superoxide anions in those from SHR. The lack of a modulatory response to NO in ventricular strips from SHR is probably a result of an alteration of mechanisms in NO-signalling pathway downstream of cGMP formation in SHR hearts.

Vascular sodium pump: endothelial modulation and alterations in some pathological processes and aging

The vascular Na+ pump maintains intracellular ionic concentration and controls membrane potential. Its inhibition by cardiac glycosides enhances the intracellular Na+ concentration. This in turn activates the Na+-Ca2+ exchange mechanism, which induces intracellular Ca2+ increase, membrane depolarization, and noradrenaline release from perivascular adrenergic nerve endings; mechanisms that promote vasoconstriction. This article reviews the relevance of the Na+ pump in vascular tone regulation and the modulation of its activity by the endothelium. The endothelium negatively modulates the vasoconstriction elicited by Na+ pump inhibition by the release of nitric oxide, according to some authors, or an unknown factor, as suggested by others. The possible existence of endogenous digitalis-like factors is also reviewed, as is the involvement of the vascular Na+ pump in some cardiovascular disorders and aging.

Chiral discrimination of the analgesic cizolirtine by using cyclodextrins: A (1)H NMR study on the solution structures of their host-guest complexes

The use of four cyclodextrins (three native and one beta-CD derivative) as NMR chiral solvating agents to resolve the enantiomers of (+/-)-cizolirtine, 1, and its chemical precursor (the carbinol, (+/-)-2), was investigated. The best enantiodiscrimination occurred when beta-cyclodextrin was used. ROESY experiments were performed to qualitatively ascertain the most probable host-guest structures in D(2)O solution, and the binding features found were explained in terms of spatial fitting of the guest molecules into the macrocyclic cavities. No geometrical differences were noted between the two diastereomeric complexes formed by a cyclodextrin and a racemic substrate, so the magnetic nonequivalence induced on guest protons by the enantioselective binding had to be explained as a result of subtle disparities in the orientation and/or the conformational state of the complexed enantiomers.

Effects of CS-US interval modification on diminution of the unconditioned response in electrodermal classical conditioning

The purpose of this experiment was to study whether interstimulus interval (ISI) modification differentially affects the amplitude of the unconditioned response (UR amp.). Seventy-five volunteer subjects received discrimination training with an interval between conditioned stimulus (CS) and unconditioned stimulus (US; aversive white noise) of 8 s. After the discrimination training phase, subjects exhibiting discriminative control were randomized into three groups that differed according to the ISI, of 1, 5 or 8 s. The subjects of each group were then tested with five presentations of CS + /US. The results demonstrate that the UR showed a greater amplitude when an ISI of 8 s was used than with ISIs of 1 or 5 s. No significant differences were found between the UR amp. of the 1- and 5-s ISI groups. These findings are discussed as a result of a hypothetical experimentally induced blend of the anticipatory CRs with the UR.

Effects of conditioned stimulus presentation on diminution of the unconditioned response in aversive classical conditioning

The purpose of this experiment was to study whether conditioned diminution of the unconditioned response (UR) is a phenomenon with an associative basis. Discriminative electrodermal conditioning was used with an interval between the conditioned stimulus (CS) and unconditioned stimulus (US; aversive white-noise) of 8 s. Fifty-nine volunteer subjects received discrimination training in which one CS was reinforced (CS+ /US) and a second CS was non-reinforced (CS-). After this discriminative training phase, participants were tested using intermixed trials in which a US was preceded by either a CS+, a CS-, or a neutral stimulus (NS). The results indicated that the skin conductance response amplitude of the UR was lower when the US was preceded by the CS+ than when the US was preceded by the CS- or the NS. However, NS/US presentations elicited URs of greater amplitude than those of the CS- /US presentations. The results can be explained in terms of orienting reflex reinstatement. In addition, it is argued that conditioned diminution has an associative basis.

Long-term follow-up of pyrolytic carbon metacarpophalangeal implants

BACKGROUND

The metacarpophalangeal joint is the most commonly involved joint when rheumatoid arthritis affects the hand. Many prosthetic implants have been designed for the replacement of this joint. Although studies of these implants have shown relief of pain, they have generally demonstrated a poor range of motion, progression of ulnar drift, and bone loss, as well as failure, fracture, and dislocation of the implant.

METHODS

From December 1979 to February 1987, 151 pyrolytic carbon metacarpophalangeal implants were inserted in fifty-three patients. The implants had an articulating, unconstrained design with a hemispherical head and grooved, offset stems. Forty-four patients had rheumatoid arthritis; five, posttraumatic arthritis; three, osteoarthritis; and one, systemic lupus erythematosus. Three patients (eleven implants) were lost to long-term follow-up, and twenty patients (fifty-one functioning implants) died after the implant had been in situ for an average of 7.2 years. Eighteen implants (12 percent) in eleven patients were revised. Fourteen of the eighteen implants were replaced with a silicone-elastomer or another type of implant, and the remaining four were removed and a pyrolytic carbon implant was reinserted with the addition of bone cement or bone graft, or both. Twenty-six patients (seventy-one implants) were available for long-term review at an average of 11.7 years (range, 10.1 to 16.0 years) after implantation.

RESULTS

The implants improved the arc of motion of the fingers by an average of 13 degrees and elevated the arc by an average of 16 degrees. As a result, fingers were in a more functional, extended position. A complete set of preoperative, postoperative, and follow-up radiographs was available for fifty-three of the seventy-one implants that were followed long term. There was a high prevalence of joint stability: fifty (94 percent) of the fifty-three implants were in a reduced position postoperatively, and forty-one (82 percent) of those fifty implants were still in the postoperative reduced position at the time of long-term follow-up. Ulnar deviation averaged 20 degrees preoperatively and 19 degrees at the time of follow-up, with only the long finger having an increase in deviation. No adverse remodeling or resorption of bone was seen. Fifty (94 percent) of the fifty-three implants had evidence of osseointegration, with sclerosis around the end and shaft of the prosthetic stems. Radiolucent changes were seen adjacent to twelve implants. There was minimum-to-moderate subsidence (four millimeters or less) of thirty-four implants; most of the subsidence occurred immediately postoperatively. Survivorship analysis demonstrated an average annual failure rate of 2.1 percent and a sixteen-year survival rate of 70.3 percent. The five and ten-year survival rates were 82.3 percent (95 percent confidence interval, 74.6 to 88.2 percent) and 81.4 percent (95 percent confidence interval, 73.0 to 87.8 percent), respectively. None of the revised implants had any visible changes of wear or deformity of the surfaces or stems. Four instances of chronic inflammatory tissue and three instances of proliferative synovitis were noted histologically. Focal pigment deposits were seen in three fingers, one of which had removal of the implant two months after a fracture. No evidence of intracellular particles or particulate synovitis was found.

CONCLUSIONS

The results of this study demonstrate that pyrolytic carbon is a biologically and biomechanically compatible, wear-resistant, and durable material for arthroplasty of the metacarpophalangeal joint.

Effect of atrial natriuretic peptide and cyclic GMP phosphodiesterase inhibition on collagen synthesis by adult cardiac fibroblasts

1. Cardiac fibroblasts play an important role in the pathophysiology of cardiac remodelling induced by hypertension and myocardial infarction by undergoing proliferation and depositing extracellular matrix proteins such as collagen. We have examined the effects of atrial natriuretic peptide (ANP) on proliferation and collagen synthesis by adult rat and human cardiac fibroblasts in culture. 2. In cells from both species radioligand studies using 125I-ANP suggested that the majority of binding sites (> 85%) were non-guanylyl cyclase-linked (NPR-C subtype). Nonetheless ANP (10(-9) to 10(-6) M), in the presence of zaprinast, an inhibitor of phosphodiesterase 5 (PDE5), increased fibroblast cyclic GMP levels 3-5 fold in a concentration-dependent manner (P < 0.05). 3. ANP (10(-11) to 10(-6) M), a NPR-C ligand, C-ANF4-23 (10(-11) to 10(-6) M) and zaprinast alone had no significant effect on either basal or serum-stimulated DNA synthesis or fibroblast number. In combination with zaprinast (10(-5) M), however, ANP (10(-9) to 10(-6) M) but not C-ANF4-23 (10(-7) M) inhibited markedly both basal and stimulated fibroblast mitogenesis, an effect reproduced by 8-bromo-cyclic GMP (10(-5) to 10(-3) M). 4. Collagen synthesis, determined by measuring hydroxyproline levels, was stimulated with transforming growth factor-beta1 (40 pM), angiotensin II (10(-7) M) or 2% foetal bovine serum. The increase in collagen production, normalised by cell number, was reduced dramatically (to at or near basal production) by ANP (10(-9) to 10(-7) M) but not C-ANF4-23 (10(-7) M) in the presence of zaprinast. Again 8-bromo-cyclic GMP (10(-5) to 10(-3) M) reproduced the effect. 5. ANP is capable of inhibiting collagen synthesis in adult rat and human cardiac fibroblasts via cyclic GMP, a property unmasked and enhanced by inhibition of PDE5.

Role of lipid peroxidation and the glutathione-dependent antioxidant system in the impairment of endothelium-dependent relaxations with age

1. Age-related changes in the blood prooxidant-antioxidant state, as well as its influence on the relaxant responses to acetylcholine (ACh) were studied in the tail artery from 6-, 24- and 30-month-old Sprague-Dawley (SD) rats. 2. Malondialdehyde (MDA) plasma levels increased 2 and 3 times in 24- and 30-month-old rats, respectively, when compared with 6-month-old rats (0.43+/-0.09 microM). This increase was accompanied by an induction of 6-phosphogluconate dehydrogenase (6PG-DH) and glutathione reductase (GR) activities in red blood cells from 24-month-old rats. In 30-month-old rats, a further induction of these enzymatic activities, as well as glucose-6-phosphate dehydrogenase (G6P-DH) and glutathione peroxidase (GPx) activities was observed. 3. No differences with age were found in the concentration-response curves to ACh in isolated tail artery segments from 6- and 24-month-old rats precontracted with 0.3 microM noradrenaline (NA). However, a decrease in sensitivity to ACh-induced relaxation was observed in 30-month-old rats; EC30 values were 3.5 (1.3-8.0) x 10(-7) M and 18.1 (8.9-30.1) x 10(-7) M for 6- and 30-month-old rats, respectively. Moreover, a decrease in maximum ACh relaxation (10 microM) was found in 30-month-old rats in comparison with that obtained in 6-month-old rats (58.5+/-3.9% and 42.5+/-3.4% of previous NA contraction, respectively). 4. Incubation of tail artery segments with MDA (0.5, 1 or 10 microM) caused a reduction of ACh-induced relaxations that was different in the three ages. Thus, the reduction of ACh-induced relaxations became significant with 0.5 microM MDA in 6-, with 1 microM MDA in 24-, and with 10 microM MDA in 30-month-old rats. In addition, MDA did not cause a shift in the concentration-response curve to ACh, but a decrease in the maximum response. 5. Superoxide dismutase (SOD; 150 u ml(-1), a superoxide anion scavenger) reversed the inhibitory effect of MDA on ACh-induced relaxations at all ages studied. 6. We conclude that: (1) ageing produces an increase in lipid peroxidation process, as indicated by the increase in MDA plasma levels, that is accompanied by an induction of lipid peroxide detoxification enzymes: (2) the changes in prooxidant-antioxidant equilibrium with age contribute, at least partially, to the impairment of the relaxant responses evoked by ACh; and (3) the effect of MDA appears to be mediated by superoxide anion at all ages studied.

Monocyte phagolysosomal fusion in children born to human immunodeficiency virus-infected mothers

BACKGROUND

Previously we demonstrated that monocyte phagolysosomal fusion is impaired in chronic HIV infection in adult patients.

METHODS

We studied the phagolysosomal fusion of peripheral blood monocytes from 45 children vertically infected with HIV, 38 noninfected infants born to HIV-positive mothers and 14 children born to HIV-seronegative women, by a cytomorphologic method in which acridine orange is used as a fusion marker.

RESULTS

The mean percentages of phagolysosomal fusion +/-SD were 42 +/- 16.1 for HIV-positive children, 55.3 +/- 15.5 for HIV-negative infants born to HIV-infected mothers and 58.2 +/- 12.7 for normal controls. Monocyte phagolysosomal fusion of HIV-infected children was significantly decreased in comparison to noninfected and normal infants (P < 0.001), while there was no difference between the two latter groups. Phagolysosomal fusion impairment in HIV-infected infants inversely correlated with age (r = -0.4527; P < 0.002) and directly correlated with CD4+ T cell counts (r = 0.393; P = 0.03). Moreover, phagolysosomal fusion strongly correlated with clinical manifestations; this function was significantly impaired in moderately and severely symptomatic HIV-infected children with respect to those who remained asymptomatic or mildly symptomatic (P < 0.05).

CONCLUSIONS

Our results suggest that monocyte function in HIV-infected children progressively deteriorates, closely related to the severity of the clinical symptoms.

Endothelium stimulates the vascular smooth muscle cell Na/K pump of normotensive and hypertensive rats by a protein kinase C pathway

OBJECTIVE

To investigate the mechanisms involved in the endothelial stimulation of the vascular smooth muscle cell Na/K pump and their possible alteration by hypertension.

METHODS

The Na/K pump activity of vascular smooth muscle cells (VSMC) from normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) was studied using the radioactive analogue of K+ 86Rb+. Conditioned medium of bovine endothelial aortic cells was used to investigate the endothelial modulation of VSMC Na/K pump activity.

RESULTS

Conditioned medium enhanced VSMC Na/K pump activity (ouabain-sensitive 86Rb+ uptake), this effect being higher in SHR cells. This stimulatory effect was neither modified in Na(+)-loaded cells from both rat strains nor inhibited by the Na/H exchange blocker amiloride. Permeable analogues of cyclic adenosine and guanosine monophosphates did not modify the baseline VSMC Na/K pump activity of WKY rats and SHR, and subsequently the guanylate cyclase inhibitor methylene blue did not alter the conditioned medium-induced stimulation of the pump. However, the Ca(2+)-channel inhibitor nifedipine reduced the Na/K pump stimulation by conditioned medium, this decrease being higher in WKY rat than in SHR VSMC. Moreover, treatment with phorbol 12,13-dibutyrate for 24 h or with the protein kinase C inhibitor staurosporine for 15 min reduced the conditioned medium-induced Na/K pump activation in both VSMC cultures.

CONCLUSIONS

Na/K pump stimulation by conditioned medium of endothelial cells is mediated mainly via activation of protein kinase C in VSMC from either WKY or SHR VSMC. However, SHR VSMC show some alterations in their intracellular signalling pathways.

Palytoxin-induced Na+ influx into yeast cells expressing the mammalian sodium pump is due to the formation of a channel within the enzyme

Palytoxin forms ionic channels in animal cell membranes but does not have similar effects on bacteria or yeast cells. These channels appear to be associated with the sodium pump. Using a heterologous expression system for the mammalian sodium pump in the yeast Saccharomyces cerevisiae, we recently demonstrated palytoxin-induced K+ efflux from yeast cells. Using the same system, we now show that the palytoxin-induced Na+ influx measured by others in animal cells is also directly associated with the sodium pump. Under the influence of palytoxin, yeast cells that express the mammalian sodium pump exchange extracellular Na+ ions for intracellular K+ ions with a stoichiometry of approximately 1:1. Both fluxes can be inhibited by ouabain. K+ efflux can also be observed when extracellular Na+ is replaced by Li+, Cs+, or NH4+. These data suggest that all palytoxin-induced ion fluxes measured so far in various cell systems are directly associated with the sodium pump. Palytoxin-induced Na+ influx or K+ efflux does not occur with yeast cells that express a truncated form of the sodium pump that is missing 44 of the carboxyl-terminal amino acids of the alpha 1 subunit. Scatchard analysis reveals only a slightly lower affinity of the truncated form for [3H]ouabain compared with the affinity of the native enzyme. Yeast cells expressing the truncated enzyme can bind [3H]ouabain, which can be displaced by palytoxin. Therefore, the inability of the truncated form to conduct ions under the influence of palytoxin is not due to the removal of the palytoxin binding site but rather to the removal of a part of the enzyme that participates in a direct or indirect way in the formation of the palytoxin-induced channel. Based on these findings, we conclude that palytoxin opens a channel within and not merely in the vicinity of the sodium pump. This might be the same channel that under normal conditions actively transports Na+ and K+ ions.

Endothelial stimulation of sodium pump in cultured vascular smooth muscle

We studied vascular sodium pump activity and its regulation by vasoactive agents and endothelium in cultured aortic vascular smooth muscle cells from normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Baseline sodium pump activity (ouabain-inhibitable 86Rb+ uptake) was similar in cells from both rat strains. Angiotensin II and endothelin-1 increased ouabain-inhibitable 86Rb+ uptake more in SHR than WKY cells, whereas no effects were obtained with sodium nitroprusside, 8-bromo-cGMP, or iloprost. We examined the influence of endothelium on vascular sodium pump activity either by coculturing smooth muscle and endothelial cells or by using conditioned medium. Both coculture for 24 hours with endothelial cells and treatment with conditioned medium increased smooth muscle cell sodium pump activity, this effect being higher in SHR cells. These results suggest that the endothelium may modulate sodium pump activity in the underlying smooth muscle by releasing a diffusible compound, which is more active on SHR smooth muscle. The conditioned medium obtained in the presence of inhibitors of angiotensin-converting enzyme, endothelin-1-converting enzyme, cyclooxygenase, lipoxygenase, and nitric oxide synthase had no effect on the ability of conditioned medium to increase sodium pump activity, suggesting that angiotensin II, endothelin-1, eicosanoids, and nitric oxide are not involved in this stimulatory effect. The nature of the possible endothelial factor involved is still unknown, but it possesses a molecular weight between 25 and 50 kD, is heat stable, and is sensitive to trypsin treatment. We propose it could be a growth factor.

Influence of endothelium on cultured vascular smooth muscle cell proliferation

The endothelium exerts a large influence on the underlying vascular smooth muscle, not only by the release of both contracting and relaxing factors but also by its ability to synthesize a large number of molecules that influence vascular smooth muscle growth. In addition to well-characterized growth promoters or growth inhibitors, some endothelium-derived factors, originally described as vasoactive compounds, seem to possess growth-regulatory properties. The vasoconstrictor endothelin-1 elicited a dose-dependent increase of cultured vascular smooth muscle cell DNA synthesis with a maximal effect of 57 +/- 14% over basal levels, whereas vasodilators such as prostacyclin, sodium nitroprusside, and 8-bromoguanosine 3':5'-cyclic monophosphate reduced DNA synthesis by 19 +/- 5%, 22 +/- 2%, and 31 +/- 3%, respectively. Medium conditioned by cultured bovine aortic endothelial cells markedly stimulated both DNA synthesis and proliferation of smooth muscle cells. When medium was conditioned in the presence of the endothelin-converting enzyme inhibitor phosphoramidon, the mitogenic effect was significantly reduced, thus indicating a role for endothelin in the stimulation of smooth muscle cell growth by endothelial cells. However, when both cell types were maintained in a coculture system, a 13 +/- 2% decrease of DNA synthesis was observed in smooth muscle cultures. The addition of the nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester, the cyclooxygenase inhibitor indomethacin, or both during the coculture period did not revert the antiproliferative effect of endothelial cells in coculture, thereby indicating it is not likely due to these unstable endothelium-derived vasorelaxant molecules.

[Health council: conclusions after 3-year experience]

OBJECTIVE

To evaluate the Health Council from 1990 to 1993. To find out what is the knowledge and opinion of the Community about Health Council.

DESIGN

Observational, descriptive and crossover study. SITE. Health Council in El Higuerón Health Center. Rural population. Córdoba.

PARTICIPANTS

Social agents and professionals who had participated in the Health Council's meetings during the three last years. Community of our suburb.

MEASUREMENTS AND MAIN RESULTS

The records from three years ago have been analysed. A questionnaire was developed and answered in the community. Three focal groups, which had been done with social agents and health professional, have been analysed as well. Two groups of activities have been discussed: in relation to health problem of the community and in relation to Health Center's working. The 70% of them were carried out. Social agents took the initiative in 36%. Questionnaire: 92% of community think they must participate in the health's problems; 40% of community know the Health Council. Focal groups: Health Council is useful for improving the relation between Health Center and Community or for getting the Community to participate in this subject.

CONCLUSIONS

It is important to remain and increase its utilization. It is necessary to divulge the Health Council and its function.

7-azetidinylquinolones as antibacterial agents. 2. Synthesis and biological activity of 7-(2,3-disubstituted-1-azetidinyl)-4-oxoquinoline- and -1,8-naphthyridine-3-carboxylic acids. Properties and structure-activity relationships of quinolones with an azetidine moiety

A series of 7-(2,3-disubstituted-1-azetidinyl)-1,4-dihydro-6-fluoro-4- oxoquinoline- and -1,8-naphthyridine-3-carboxylic acids, with varied substituents at the 1-, 5-, and 8-positions, was prepared to study the effects on potency and physicochemical properties of the substituent at position 2 of the azetidine moiety. The activity of the title compounds was determined in vitro against Gram-positive and Gram-negative bacteria, and the in vivo efficacy of selected derivatives was determined using a mouse infection model. The X-ray crystal structures of 6b, 6c, and 6d were found to be in reasonable agreement with the corresponding AM1 calculated geometries. Correlations between antibacterial potency of all the synthesized 7-azetidinylquinolones and naphthyridines and their calculated electronic properties and experimental capacity factors were established. Antibacterial efficacy and pharmacokinetic and physicochemical properties of selected derivatives were compared to the relevant 7-(3-amino-1-azetidinyl) and 7-(3-amino-3-methyl-1-azetidinyl) analogues (for Part 1, see: J. Med. Chem. 1993, 36, 801-810). A combination of a cyclopropyl or a substituted phenyl group at N-1 and a trans-3-amino-2-methyl-1-azetidinyl group at C-7 conferred the best overall antibacterial, pharmacokinetic, and physicochemical properties to the azetidinylquinolones studied.

Phorbol dibutyrate induces contractions in bovine cerebral arteries by an extracellular calcium-independent mechanism

The aim of the present study was to analyse the ability of phorbol 12,13-dibutyrate (PDB) to activate protein kinase C (PKC), measured by its capacity to translocate the enzyme from the cytosol to the membrane fraction, as well as to induce vasconstrictive responses in segments from branches of bovine cerebral arteries. PDB (0.1 microM) produced a marked translocation of PKC activity from the cytosolic to the membranous fraction. This drug induced concentration-dependent contractions which were slow in onset. The contraction elicited by PDB was reduced by the PKC inhibitor, staurosporine (1 and 10 nM), but unaltered by both Ca(2+)-free medium containing 3 mM EGTA and the Ca(2+)-channel antagonist, nifedipine (1 microM). Preincubation of segments with PDB (10 and 30 nM) reduced the vasoconstriction elicited by 5-hydroxytryptamine (5-HT) in a concentration- and preincubation time-dependent manner. These data indicate that bovine cerebral arteries possess cytosolic and membranous PKC activities, that the vasoconstrictive responses induced by PDB were independent of extracellular Ca2+, that cytosolic C-kinase is translocated to the membrane and probably down-regulated by PDB, and that this enzyme is not involved in 5-HT responses, but is down-regulated by PDB.

Right ventricular pressure-volume relations in chronic lung disease

Thirty-four patients with chronic lung disease in stable condition were studied at supine rest (RS), at rest with the legs raised (LR), and during two levels of exercise: E1, 0 or 20 W, E2, 20 or 40 W. Five patients had normal spirometry (group 1), six patients had normal vital capacity but FEV1/VC below 70% (group 2), and 23 patients had VC below 95% of normal and FEV1/VC below 70% (group 3); group 3 was subdivided into group 3a (n = 14) without, and group 3b (n = 9) with a history of right heart failure (RHF). Right ventricular end-diastolic (RVEDV) and end-systolic (RVESV) volumes were computed from stroke volume and right ventricular ejection fraction (RVEF). RVEF at rest was correlated with lung function variables. Changes in RVEF from LR to E2 were normal, i.e. above 0.05, except for in group 3b, where RVEF did not increase with exercise. Relation between RVESV and pressure, and changes in stroke volume with RVEDV from LR to E2 were also abnormal in group 3b. These results show that in patients with chronic lung disease RVEF at rest reflects lung function, whereas its adaptation to exercise is impaired only in patients who have experienced RHF episodes.

Comparison of the vasoconstrictor responses induced by endothelin and phorbol 12,13-dibutyrate in bovine cerebral arteries

The vascular effects of endothelin-1 (ET-1) were compared with those elicited by phorbol 12,13-dibutyrate (PDB), an activator of the protein kinase C (PKC), to analyze the involvement of this enzyme on ET-1 responses. PDB and ET-1 caused slow-developing contractions (sustained and transient, respectively), which were reduced by the PKC inhibitor, staurosporine (1 and 10 nM). Only the contractile effects evoked by ET-1 were reduced in Ca-free medium and by the Ca channel antagonist, nifedipine (1 microM), and increased by the Ca channel agonist, BAY K 8644 (10 nM). PDB (10 and 30 nM) preincubation reduced the vasoconstriction elicited by 5-hydroxytryptamine (5-HT; 0.01, 0.1 and 1 microM) in a way dependent on phorbol concentration and preincubation time, whereas ET-1 (1 nM) increased the contractile response to 5-HT (0.1 microM). Furthermore, PDB (0.1 microM) also reduced the responses elicited by ET-1 (30 microM) and vice versa. ET-1 (0.1 microM) induced transient translocation of PKC activity from the cytosol to the membrane, which was less than that produced by PDB (0.1 microM). Electrical stimulation induced [3H]noradrenaline (NA) release, which was increased by PDB (10 and 100 nM) and not affected by ET-1 (10 nM). These results indicate: (1) the responses induced by PDB and ET-1 were independent and dependent on extracellular Ca, respectively; (2) PKC is involved in NA release and 5-HT responses, but mainly in desensitization of these responses, and (3) PKC is activated by ET-1 and is implicated in vascular actions of ET-1, but other mechanisms, such as the activation of ET-1 receptors and opening of dihydropyridine-sensitive Ca channels also appear to be involved.

Vascular smooth muscle proliferation in hypertensive transgenic rats

In vascular smooth muscle cell (VSMC) cultures from Sprague-Dawley (SD) and hypertensive transgenic rats for the mouse renin gene Ren-2 (TGR), the DNA synthesis, which was analyzed by the uptake of [3H]thymidine, was higher in TGR than SD VSMCs (2.5- to 8-fold, mean of 5.6-fold) under basal conditions. DNA synthesis was increased by fetal calf serum (10%) in SD cells more than in TGR VSMCs, and was decreased by heparin (400 micrograms/ml) and by phorbol-12,13-dibutyrate (10(-7) M) in TGR VSMCs to a higher degree than in SD cells. Neither endothelin (10(-7) M), angiotensinogen (10(-8) M), the renin inhibitor CGP 29,287 (10(-4) M), angiotensin I (10(-7) M), captopril (10(-5) M), angiotensin II (10(-7) M), nor saralasin (10(-6) M) modified DNA synthesis in either type of VSMCs. Sodium nitroprusside (10(-4) and 10(-3) M) increased DNA synthesis in both kinds of VSMCs but in TGR cultures it became toxic at 10(-3) M. 8-Bromocyclic GMP (10(-7) to 10(-5) M) reduced DNA synthesis in SD cells more than in TGR VSMCs. These results suggest that (a) cellular mechanisms of proliferation appear to be more activated in TGR VSMCs, likely involving a protein kinase C-dependent pathway but not the renin-angiotensin system, and (b) in both type of cells, sodium nitroprusside possesses proliferative properties whereas 8-bromocyclic GMP has antiproliferative properties.