Wannier-stark ladders in one-dimensional elastic systems

The optical analogues of Bloch oscillations and their associated Wannier-Stark ladders have been recently analyzed. In this Letter we propose an elastic realization of these ladders, employing for this purpose the torsional vibrations of specially designed one-dimensional elastic systems. We have measured, for the first time, the ladder wave amplitudes, which are not directly accessible either in the quantum-mechanical or optical cases. The wave amplitudes are spatially localized and coincide rather well with theoretically predicted amplitudes. The rods we analyze can be used to localize different frequencies in different parts of the elastic systems and vice versa.

Captopril effect on prostaglandin E2, thromboxane B2 and proteinuria in lupus nephritis patients

OBJECTIVE

High urinary Prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) levels have been reported in lupus nephritis (LN). Captopril diminishes proteinuria and improves glomerular filtration rate (GFR), and may have effect on immune function. We evaluate captopril effect on urinary PGE2, and TxB2.

METHODS

Eighteen LN patients were randomly assigned to two groups. Group 1 received only prednisone plus cyclophosphamide. Group 2 received also captopril. Serum creatinine, GFR, RPF, urinary proteins, PGE2 and TxB2, were assessed.

RESULTS

There were no differences between the initial and final assessments in Group 1. Group 2 showed a significant decrement in proteinuria (p=0.003) and serum creatinine (p=0.01) at the end of the study. PGE2 decreased significantly when compared with the initial value (p=0.02).

CONCLUSION

Captopril plus usual treatment, improved serum creatinine and decreased proteinuria in parallel with prostaglandin E2 reduction. This effect is not related to changes in GFR or RPF. Captopril may have an immunomodulatory effect on local inflammatory processes in lupus nephritis.

Leishmaniasis as an opportunistic infection in HIV-infected patients: determinants of relapse and mortality in a collaborative study of 228 episodes in a Mediterreanean region

The clinical presentation of visceral leishmaniasis shares similarities with other geographically specific infectious diseases associated with AIDS in terms of relapsing course and atypical presentation. However, visceral leishmaniasis has not, until now, been included in the AIDS case definition. The aim of this study was to describe the clinical features and determinants for relapse and case-fatality of visceral leishmaniasis in HIV-infected patients from a Spanish Mediterranean area. A chart review was conducted in 16 hospitals in the autonomous communities of Valencia and Murcia (Spain). From 1988 to 2001, a total of 228 episodes of visceral leishmaniasis were diagnosed in 155 HIV-infected patients by the detection of amastigotes in bone marrow aspirates or in other tissue samples. Most patients had advanced HIV disease, with a median CD4(+) lymphocyte cell count of 55 cells x 10(9) l, and 56% of them had a previous AIDS-indicator disease. The median duration of follow-up was 8.4 months. HIV-infected patients with visceral leishmaniasis presented with fever (76%), hepatomegaly (77%), splenomegaly (78%), and varying degrees of cytopenias. Leishmania was detected in atypical sites in 22 (14%) patients. A total of 37 (24%) patients had a relapse of visceral leishmaniasis. Female gender was a risk factor for relapse, whereas administration of secondary prophylaxis for visceral leishmaniasis and a completed therapy for visceral leishmaniasis were protective factors against relapse. A total of 86 (54%) patients died. Independent determinants for survival were CD4(+) lymphocyte cell count, completed therapy for leishmania, and secondary prophylaxis for visceral leishmaniasis. The findings show that, in HIV-infected patients, visceral leishmaniasis occurs in late stages of HIV disease and often has a relapsing course. Secondary prophylaxis reduces the risk of relapse. Visceral leishmaniasis in the HIV-infected population should be included in the CDC clinical category C for the definition of AIDS in the same way that other geographically specific opportunistic infections are included.

Lack of the alanine–serine–cysteine transporter 1 causes tremors, seizures, and early postnatal death in mice

The Na(+)-independent alanine-serine-cysteine transporter 1 (Asc-1) is exclusively expressed in neuronal structures throughout the central nervous system (CNS). Asc-1 transports small neutral amino acids with high affinity especially for D-serine and glycine (K(i): 8-12 microM), two endogenous glutamate co-agonists that activate N-methyl-D-aspartate (NMDA) receptors through interacting with the strychnine-insensitive glycine binding-site. By regulating D-serine (and possibly glycine) levels in the synaptic cleft, Asc-1 may play an important role in controlling neuronal excitability. We generated asc-1 gene knockout (asc-1(-/-)) mice to test this hypothesis. Behavioral phenotyping combined with electroencephalogram (EEG) recordings revealed that asc-1(-/-) mice developed tremors, ataxia, and seizures that resulted in early postnatal death. Both tremors and seizures were reduced by the NMDA receptor antagonist MK-801. Extracellular recordings from asc-1(-/-) brain slices indicated that the spontaneous seizure activity did not originate in the hippocampus, although, in this region, a relative increase in evoked synaptic responses was observed under nominal Mg(2+)-free conditions. Taken together with the known neurochemistry and neuronal distribution of the Asc-1 transporter, these results indicate that the mechanism underlying the behavioral hyperexcitability in mutant mice is likely due to overactivation of NMDA receptors, presumably resulting from elevated extracellular D-serine. Our study provides the first evidence to support the notion that Asc-1 transporter plays a critical role in regulating neuronal excitability, and indicate that the transporter is vital for normal CNS function and essential to postnatal survival of mice.

Slow phase relaxation as a route to quantum computing beyond the quantum chaos border

We reveal that phase memory can be much longer than energy relaxation in systems with exponentially large dimensions of Hilbert space; this finding is documented by 50 years of nuclear experiments, though the information is somewhat hidden. For quantum computers Hilbert spaces of dimension 2(100) or larger will be typical and therefore this effect may contribute significantly to reduce the problems of scaling of quantum computers to a useful number of qubits.

Importance of early repair of isolated abdominal aortic dissecting aneurysm

BACKGROUND

Since the available information on isolated abdominal aortic dissecting aneurysm (AADA) is mainly related to case reports or reports of small groups of patients, its natural history remains undetermined and there is no agreement on its optimal management. The purpose of this study is to define the features and pattern of development of this unusual entity as well as to propose criteria for treatment based on our own experience and previously published data.

PATIENTS AND METHODS

We retrospectively evaluated the history of 6 patients diagnosed with AADA. The patients were 5 males and 1 female. The mean age was 71 +/- 8 years (range: 61-80 years), and the mean aneurysm diameter was 54 +/- 14 mm (range: 35-70 mm). All of these patients were hypertensive (100%). History of cerebrovascular accident, ischemic heart disease, peripheral arterial disease, or diabetes mellitus was present in 1 patient, respectively. Two patients developed mycotic AADA.

RESULTS

Emergency operations had been performed in 3 cases, and scheduled surgical reconstruction in the remaining 3 cases. Operation consisted of aneurysmectomy and graft replacement of the diseased aortic segment in all cases. One patient treated in an emergency setting died subsequently of multisystem organ failure, but the others did well.

CONCLUSION

Symptomatic patients or patients at good risk should undergo surgical repair earlier than in the case of abdominal aortic aneurysm without dissection (AAA). Dissection in addition to an AAA will further increase the weakness of the aortic wall and the possibility of aortic rupture will become higher.

Locally periodic Timoshenko rod: experiment and theory

The flexural vibrations of a locally periodic rod, which consists of N unit cells, are discussed both from the experimental and theoretical points of view. Timoshenko's beam theory and the transfer matrix method are used to calculate the normal-mode frequencies and amplitudes. The theoretical values are then compared with the experimental ones, which are obtained using an electromagnetic acoustic transducer (EMAT). Good agreement between the numerical results and the experimental measurements is obtained. It is shown that as N grows, a band spectrum emerges.

Stenosis of the abdominal aorta caused by fibromuscular dysplasia

Fibromuscular dysplasia of the aorta is an exceedingly rare disease with 26 cases reported to date in Medline. We present a case of stenosis of the infrarenal abdominal aorta in a 49-year-old woman with a history of intermittent claudication. The patient underwent aortic endarterectomy, and subsequent anatomopathologic examination of the specimen revealed fibromuscular dysplasia. The possible causes of aortic stenosis in this case, its angiographic findings, and the alternatives of treatment are discussed.

Health-Related Quality of Life in HIV Patients Switching to Twice-Daily Indinavir/Ritonavir Regimen or Continuing with Three-Times-Daily Indinavir-Based Therapy

Objective

To evaluate health-related quality of life (HRQoL) changes in patients treated with indinavir three-times daily after switching to a twice-daily indinavir/ritonavir regimen or continuing with the same regimen.

Methods

Patients on HAART including indinavir three-times-daily with undetectable viral load were randomly assigned to continue with this therapy or to change to a twice-daily indinavir/ritonavir (800/100 mg) regimen. The Medical Outcomes Study HIV Health Survey (MOS-HIV) questionnaire was used as the HRQoL measure.

Results

A total of 118 patients participated in the study, of which 59 (50%) were randomly assigned to continue with the three-times-daily regimen. Patients had a mean age of 39 years and 80% of them were male. At baseline, subjects included in the three-times-daily group presented a significantly greater number of symptoms than subjects in the twice-daily group, but no statistically significant differences were observed in MOS-HIV scores between the groups. In the intention-to-treat (ITT) analysis, a reduction in HRQoL scores was observed in both groups, which was greater in the twice-daily group. In the per protocol analysis, reduction of HRQoL was minimal.

Conclusions

A HRQoL deterioration, greater in the twice-daily group, was observed in this study in the ITT analysis, while HRQoL remained stable in both groups in patients who continued with and tolerated the allocated regimen.

Excision and V–Y plasty reconstruction for giant condyloma acuminatum

BACKGROUND

Condyloma acuminata is the most common anorectal lesion in patients infected with human immunodeficiency virus (HIV). Surgical treatment can be challenging in cases where the size and extension into the anal canal make individual excision impossible. These patients require large resections and reconstruction using grafts or local flaps.

METHODS

Six patients were treated for giant perianal condylomas between 1999 and 2001. Four patients were HIV-positive, and were selected for surgical intervention after achieving a T4 count >350 and low viral replication. In 5 cases, the lesions were circularly resected up to the pectinate line and the defect was reconstructed using a bilateral V-Y plasty. In the remaining case, fulguration was possible on one side and a unilateral V-Y plasty was performed.

RESULTS

There were no infections or healing delays in this series, and the functional and aesthetic results are satisfactory.

CONCLUSION

V-Y plasties are a valid method for perianal reconstruction after resection of giant anal condyloma, with good results in selected patients with HIV infection.

Taste and odor profiles (off-flavors) in the drinking waters of the Barcelona area (1996-2000)

The Aigües de Barcelona laboratory systematically monitors the organoleptic quality of the water it supplies. The water comes mainly from the Llobregat and Ter rivers, with the two sources having cleary differentiated chemical characteristics. Water is monitored by the tasting panel, which works according to FPA (Flavor Profile Analysis) principles. This paper reports the results from the period 1996-2000: characteristic organoleptic profiles, evolution of descriptors and the overall organoleptic evaluation of the water. The results show that in Llobregat water the descriptors chlorinous, medicinal, rubbery and salty are the most relevant, whereas in Ter water fresh nature/grassy and metallic are. The Aesthetic Quality Index drawn up by our laboratory confirms that Ter water has better organoleptic quality than Llobregat water. Monitoring also found that neither water lost quality significantly within the distribution network.

Sleep deprivation effects on growth factor expression in neonatal rats: a potential role for BDNF in the mediation of delta power

The sleeping brain differs from the waking brain in its electrophysiological and molecular properties, including the expression of growth factors and immediate early genes (IEG). Sleep architecture and homeostatic regulation of sleep in neonates is distinct from that of adults. Hence, the present study addressed the question whether the unique homeostatic response to sleep deprivation in neonates is reflected in mRNA expression of the IEG cFos, brain-derived nerve growth factor (BDNF), and basic fibroblast growth factor (FGF2) in the cortex. As sleep deprivation is stressful to developing rats, we also investigated whether the increased levels of corticosterone would affect the expression of growth factors in the hippocampus, known to be sensitive to glucocorticoid levels. At postnatal days 16, 20, and 24, rats were subjected to sleep deprivation, maternal separation without sleep deprivation, sleep deprivation with 2 h recovery sleep, or no intervention. mRNA expression was quantified in the cortex and hippocampus. cFos was increased after sleep deprivation and was similar to control level after 2 h recovery sleep irrespective of age or brain region. BDNF was increased by sleep deprivation in the cortex at P20 and P24 and only at P24 in the hippocampus. FGF2 increased during recovery sleep at all ages in both brain regions. We conclude that cortical BDNF expression reflects the onset of adult sleep-homeostatic response, whereas the profile of expression of both growth factors suggests a trophic effect of mild sleep deprivation.

Spinal cord compression due to tumoral idiopatic calcinosis

STUDY DESIGN

A case of thoracic spinal cord compression due to tumoral calcinosis (TC) is reported.

SETTING

Galiza, Spain.

CASE REPORT

A 59-year-old man was admitted to our hospital with a 2-month history of gradual leg weakness and sensory deficit. The neurological examination revealed paraparesis with T12 sensory level. Magnetic resonance imaging (MRI) showed an extradural right posterolateral mass at T11-T12 level, resulting in a marked spinal cord compression. He underwent T11-T12 laminectomy and mass excision. Histological examination finally led to the diagnosis of TC.

CONCLUSION

TC is an uncommon cause of mass lesions of the spine. Since there is no typical spine TC MRI appearance, the final diagnosis is done by histological studies. TC should be considered in differential diagnosis of spinal cord compression and constitutes a treatable cause of paraparesis.

Immunogenicity of a recombinant human immunodeficiency virus (HIV)-canarypox vaccine in HIV-seronegative Ugandan volunteers: results of the HIV Network for Prevention Trials 007 Vaccine Study

In the first preventative human immunodeficiency virus (HIV) vaccine study to be carried out in Africa, 40 HIV-seronegative Ugandan volunteers were randomly assigned to receive a canarypox vector containing HIV-1 clade B (env and gag-pro) antigens (ALVAC-HIV; n = 20), control vector containing the rabies virus glycoprotein G gene (n = 10), or saline placebo (n = 10). Cytotoxic T lymphocyte activity against target cells expressing clade A, B, and D antigens was assessed using standard chromium-release and confirmatory interferon-gamma enzyme-linked immunospot (ELISPOT) assays. Neutralizing antibody responses to cell line-adapted strains and primary isolates in all 3 clades were also tested. Twenty percent of vaccine recipients generated detectable cytolytic responses to either Gag or Env, and 45% had vaccine-induced HIV-specific CD8(+) T cell responses, as measured by the ELISPOT assay. In contrast, only 5% of the control group had vaccine-specific responses. Neutralizing antibodies against primary and laboratory-adapted HIV-1 clade B strains were seen in 10% and 15% of vaccine recipients, respectively, but responses against clades A and D were not detected. Although the immunogenicity of this clade B-based vaccine was low, ALVAC-HIV elicited CD8(+) T cell responses with detectable cross-activity against clade A and D antigens in a significant proportion of vaccine recipients.

Compressional and torsional wave amplitudes in rods with periodic structures

To measure and detect elastic waves in metallic rods a low-frequency electromagnetic-acoustic transducer has been developed. Frequencies range from a few hertz up to hundreds of kilohertz. With appropriate configuration of the transducer, compressional or torsional waves can be selectively excited or detected. Although the transducer can be used in many different situations, it has been tested and applied to a locally periodic rod, which consists of a finite number of unit cells. The measured wave amplitudes are compared with theoretical ones, obtained with the one-dimensional transfer matrix method, and excellent agreement is obtained.

Albumin-coated knitted Dacron aortic prosthses. Study of postoperative inflammatory reactions

BACKGROUND

The purpose of this study was to investigate the postoperative inflammatory reactions to albumin-coated Dacron grafts (ACGs), which are used in the repair of abdominal aortic aneurysm (AAA).

METHODS

EXPERIMENTAL DESIGN

a retrospective study with a follow-up period of 14 days.

SETTING

University hospital.

PATIENTS

50 patients admitted for elective AAA repair from January 1997 to January 2000.

INTERVENTIONS

each patient underwent AAA repair with an ACG (Bard, albumin-coated Dacron graft).

MEASURES

the white blood cell (WBC) count, plasma C-reactive protein (CRP) concentration, and body temperature (BT) were determined. The preoperative data, the highest values of the postoperative data, and the values 2 weeks postsurgery were analyzed.

RESULTS

The BT, CRP, and WBC increased and peaked at the 1st week postsurgery and then decreased gradually. The BT and WBC levels returned to normal within 2 weeks. The CRP level continued to show slightly elevated values in the 2nd week, but it was not significantly different compared to the preoperative data.

CONCLUSIONS

The use of an albumin-impregnated prosthesis for the reconstruction of AAA is biocompatible, since no significant increases in inflammatory reactions are observed in the 2nd week postsurgery.

Induction of angiotensin converting enzyme in neointima after intravascular stent placement

BACKGROUND

To investigate the morphological changes of the arterial wall and the expression of angiotensin converting enzyme (ACE) in the arterial wall after stent placement in a canine model.

METHODS

Seventeen mongrel dogs underwent stent placement (Gianturco's Z stent) in the aorta. Six animals were sacrificed at 4 weeks after stent implantation, and the other 5 animals at 12 weeks. The normal aorta was harvested from 6 dogs. The specimens were stained with hematoxylin-eosin (H&E) as well as by immunohistochemistry (smooth muscle specific a-actin, and ACE). Histomorphometric analysis was performed using the sections stained with H&E and smooth muscle specific a-actin.

RESULTS

The total intimal area was significantly increased at all time points as compared with the control aorta. The a-actin positive intimal area was also significantly increased at all time points as compared with the control aorta. In the control aorta, luminal endothelial cells as well as a-actin positive medial cells occasionally exhibited faint cytoplasmic staining for ACE. In the 4- and 12-week stented aorta, a-actin positive cells in the neointima and media as well as macrophages in the adventitia stained strongly positive for ACE.

CONCLUSIONS

ACE was induced in the neointima after stent placement of the canine aorta. Considering its multiple biological actions, ACE may be associated with the pathogenesis of neointimal hyperplasia after stent placement.