An electron holography study of perpendicular magnetic tunnel junctions nanostructured by deposition on pre-patterned conducting pillars

The fabrication of multi-gigabit magnetic random access memory (MRAM) chips requires the patterning of magnetic tunnel junctions at very small dimensions (sub-30 nm) and a very dense pitch. This remains a challenge due to the difficulty in etching magnetic tunnel junction stacks. We previously proposed a strategy to circumvent this problem by depositing the magnetic tunnel junction material on prepatterned metallic pillars, resulting in the junction being naturally shaped during deposition. Upon electrical contact, the deposit on top of the pillars constitutes the magnetic storage element of the memory cell. However, in this process, the magnetic material is also deposited in the trenches between the pillars that might affect the memory cell behaviour. Here we study the magnetic interactions between the deposit on top of the pillars and in the trenches by electron holography, at room temperature and up to 325 °C. Supported by models, we show that the additional material in the trenches is not perturbing the working principle of the memory chip and can even play the role of a flux absorber which reduces the crosstalk between neighboring dots. Besides, in the studied sample, the magnetization of the 1.4 nm thick storage layer of the dots is found to switch from out-of-plane to an in-plane configuration above 125 °C, but gradually decreases with temperature. Electron holography is shown to constitute a very efficient tool for characterizing the micromagnetic configuration of the storage layer in MRAM cells.

Measurement of the Curvature-Dependent Surface Tension in Nucleating Colloidal Liquids

The curvature dependence of the surface tension is central to the nucleation of liquids, but remains difficult to access experimentally and predict theoretically. This curvature dependence arises from the curvature-dependent molecular structure, which, for small nuclei, can deviate significantly from that of the planar liquid interface. Simulations and density functional theory have been used to predict this curvature dependence, however with contradicting results. Here, we provide the first direct measurement of the curvature-dependent surface tension in nucleating colloidal liquids. We employ critical Casimir forces to finely adjust colloidal particle interactions and induce liquid nucleation, and image individual nuclei at the particle scale to measure their curvature-dependent surface tension directly from thermally excited surface distortions. Using continuum models, we elucidate the interplay between nucleus structure, particle pair potential, and surface tension. Our results reveal a 20% lower surface tension for nuclei of critical size compared to bulk liquids, leading to 3 orders of magnitude higher nucleation rates, thus highlighting the importance of surface tension curvature corrections for accurate prediction of nucleation rates.

Characterization and Applications of Marine Microbial Enzymes in Biotechnology and Probiotics for Animal Health

Marine microorganisms have been recognized as potential sources of novel enzymes because they are relatively more stable than the corresponding enzymes derived from plants and animals. Enzymes from marine microorganisms also differ from homologous enzymes in terrestrial microorganisms based on salinity, pressure, temperature, and lighting conditions. Marine microbial enzymes can be used in diverse industrial applications. This chapter will focus on the biotechnological applications of marine enzymes and also their use as a tool of marine probiotics to improve host digestion (food digestion, food absorption, and mucus utilization) and cleave molecular signals involved in quorum sensing in pathogens to control disease in aquaculture.

Critical Casimir forces for colloidal assembly

Critical Casimir forces attract increasing interest due to their opportunities for reversible particle assembly in soft matter and nano science. These forces provide a thermodynamic analogue of the celebrated quantum mechanical Casimir force that arises from the confinement of vacuum fluctuations of the electromagnetic field. In its thermodynamic analogue, solvent fluctuations, confined between suspended particles, give rise to an attractive or repulsive force between the particles. Due to its unique temperature dependence, this effect allows in situ control of reversible assembly. Both the force magnitude and range vary with the solvent correlation length in a universal manner, adjusting with temperature from fractions of the thermal energy, k B T, and nanometre range to several ten kT and micrometer length scale. Combined with recent breakthroughs in the synthesis of complex particles, critical Casimir forces promise the design and assembly of complex colloidal structures, for fundamental studies of equilibrium and out-of-equilibrium phase behaviour. This review highlights recent developments in this evolving field, with special emphasis on the dynamic interaction control to assemble colloidal structures, in and out of equilibrium.

Elementary depinning processes of magnetic domain walls under fields and currents

The probability laws associated to domain wall depinning under fields and currents have been studied in NiFe and FePt nanowires. Three basic domain wall depinning processes, associated to different potential landscapes, are found to appear identically in those systems with very different anisotropies. We show that these processes constitute the building blocks of any complex depinning mechanism. A Markovian analysis is proposed, that provides a unified picture of the depinning mechanism and an insight into the pinning potential landscape.

Switchable spin-current source controlled by magnetic domain walls

Using nonlocal spin injection, spin-orbit coupling, or spincaloritronic effects, the manipulation of pure spin currents in nanostructures underlies the development of new spintronic devices. Here, we demonstrate the possibility to create switchable pure spin current sources, controlled by magnetic domain walls. When the domain wall is located at a given point of the magnetic circuit, a pure spin current is injected into a nonmagnetic wire. Using the reciprocal measurement configuration, we demonstrate that the proposed device can also be used as a pure spin current detector. Thanks to its simple geometry, this device can be easily implemented in spintronics applications; in particular, a single current source can be used both to induce the domain wall motion and to generate the spin signal.

Controlling colloidal morphologies by critical Casimir forces

Active control over the assembly of colloidal and nanoparticles has important applications for the design of new nanostructured materials, but it is a difficult task. Here, a new method is presented to control the morphology of colloidal aggregates using critical Casimir forces. Via direct temperature control of critical Casimir forces, the particles are assembled into aggregates with well-defined architecture.

Increased vertical dimension effects on masseter muscle fiber phenotype during maturation

OBJECTIVE

To determine changes in mouse myosin heavy chain (MyHC) protein expression that may occur with a clinically relevant vertical dimension of occlusion (VDO) increase.

MATERIALS AND METHODS

Six CD-1 male mice (age: 6 weeks) underwent a 10% bite opening to replicate the clinical condition using composite on the maxillary molars and were compared to six age-matched controls. Mice were sacrificed at day 7 and 14 after bite opening. A representative masseter transverse cryosection from each animal was examined in selected sampling regions (anterior, posterior, posterior-deep, and posterior-intermediate) to assay fiber phenotype proportions and fiber size.

RESULTS

In control masseter muscles, the proportion of muscle fibers containing MyHC IIb increased in the posterior-intermediate and posterior-deep regions between 7 and 14 days (ANOVA, P < .05). The increase in the proportion of MyHC IIb fibers in the bite opening group did not occur when compared to the control group (P < .05). In addition, after 14 days of bite opening, the proportion of fibers positive for MyHC IIa was decreased in the anterior region compared to control masseter muscles. Muscle fiber diameter remained unchanged in both groups (experimental and control) and over time (P > .10).

CONCLUSION

These data are consistent with a selective plasticity of the expression of MyHC IIb protein in the deep regions of the male masseter muscle in response to a clinically relevant VDO increase.

Detection of domain-wall position and magnetization reversal in nanostructures using the magnon contribution to the resistivity

We show that magnetization reversal detection can be achieved at room temperature using the contribution of magnons to resistivity, in 50 nm wide nanowires with either perpendicular anisotropy (FePt) or in-plane magnetization (NiFe). Even though these nanowires are made from single layers, simple magnetoresistance measurements can be used to measure switching fields, or to detect the position of a domain wall along a nanowire. Surprisingly, in NiFe nanowires, and for applied fields nearly parallel to the wire, the magnon contribution is found to dominate the classical anisotropic magnetoresistance.

Successful AV fistula creation does not lead to higher catheter use: the experience by the Northwest Renal Network 16 Vascular Access Quality Improvement Program. Four years follow-up

BACKGROUND

In 2002, the Center for Medicare and Medicaid Services (CMS) required all 18 Renal Networks to participate in a Vascular Access Quality Improvement Program (QIP). The Northwest Renal Network (NWRN 16) chose to increase arteriovenous fistula (AVF) use. NWRN 16 hypothesized that strategies which targeted the improvement of AVF rate and the reduction of catheter use were the same. In December 2001, 44.2% of hemodialysis (HD) patients in the NWRN 16 received HD using an AVF which met the Dialysis Outcome Quality Initiative (K/DOQI) 40% AVF guideline for prevalent patients. However, 43% of HD facilities (2869 patients) had less than 40% of AVF and higher HD catheter rates than the average Network catheter rates (25.0 vs. 20.3%). To address the needs of underperforming facilities, NWRN 16 provided education and tools for their vascular access decision makers to promote AVF creation and catheter reduction.

METHODS

In 2002, NWRN 16 sponsored four regional workshops targeted at nephrologists, vascular surgeons, HD nurses, and interventional radiologists.

RESULTS

Percentage of AVFs in use in invited facilities increased from 31.3% pre-intervention to 56.2% at 4 yrs: 78% increase (99% confidence interval: 77.8% to 81.5%). Percentage of catheters increased from 25% to 25.8%: 3.2% change over 4 yrs (99% confidence interval: 2.5% to 4%).

CONCLUSION

The success of Network 16's AVF interventions demonstrates the effectiveness of Network education promoting multidisciplinary teamwork, and innovative strategies to increase dramatically AVF use without substantial increase in catheter use.

Creation of secondary AV fistulas from failed hemodialysis grafts: the role of routine vein mapping

Pre-existing forearm grafts lead to dilatation of upper arm veins of the ipsilateral arm that greatly facilitates the creation of secondary arteriovenous fistulas (AVF). In this retrospective review of 18 patients, the routine and periodical revision of failed grafts were discontinued. Vein mapping by physical examination or Duplex studies was performed prior to graft failure and a secondary AVF was created when the graft failed. Using this management strategy, an AVF creation success rate of 95% was achieved despite high incidence of co-morbidity factors within the patient population. This success rate demonstrates the value of vein selection by vascular mapping prior to graft failure and early vascular access planning in the successful creation of secondary AVF.

Successful multidisciplinary interventions for arterio-venous fistula creation by the Pacific Northwest Renal Network 16 vascular access quality improvement program

BACKGROUND

In December 2001, 44.2% of hemodialysis (HD) patients in the Northwest Renal Network (NWRN 16) received dialysis using an arteriovenous fistula (AVF). Substantial differences were noted in percentages of patients with AVF, ranging from 5% to 90% of the facility population, suggesting wide variation in physician practice patterns within the Network. To address the needs of facilities having < 40% AVF, NWRN 16 provided education and tools for their vascular access decision-makers to promote AVF creation.

METHODS

In 2002, the Network sponsored 4 regional workshops targeted to nephrologists, vascular surgeons, dialysis nurses, and interventional radiologists.

RESULTS

46 facilities (43% of all Network facilities) had <40% AVF in use in December, 2001, dialyzing 2940 patients (Invited Units). Percent AVF in use in all the Invited Facilities increased from 31.3% pre-intervention to 39.8% at 1 year (p<0.001 vs pre) to 56.2% at four years: 79.8% increase in the prevalent AVF rate over a four-year period (95% confidence interval: 77.8% to 81.7%).

CONCLUSION

Low prevalent AVF rates in many NWRN 16 facilities may have resulted from differences in physician practice patterns. The success of Network 16 AVF Intervention demonstrates the effectiveness of Network education promoting multidisciplinary teamwork, innovative strategies to increase AVF rates among dialysis patients.

A high-resolution reference map for cytoplasmic and membrane-associated proteins of Corynebacterium glutamicum

We present a high-resolution reference map for soluble proteins obtained from Corynebacterium glutamicum cells grown in glucose minimal medium. The analysis window covers the pl range from 4-6 and the molecular mass range from 5-100 kDa. Using overlapping narrow immobilized pH gradients for isoelectric focusing, 970 protein spots were detected after second-dimensional separation on SDS-polyacrylamide gels and colloidal Coomassie-staining. By tryptic peptide mass fingerprinting 169 protein spots were identified, representing 152 different proteins including many enzymes involved in central metabolism (18), amino acid biosynthesis (24) and nucleotide biosynthesis (11). Thirty-five of the identified proteins have no known function. A comparison of the observed and the expected physicochemical properties of the identified proteins indicated that nine proteins were covalently modified, since variants with apparently identical molecular mass, but differing pl were detected. The N-termini of eight proteins were determined by post-source decay (PSD) analysis of selected peptides. In addition to the soluble proteins, a map of the membrane-bound proteins within the pl range 4-7 is presented, which contains 660 protein spots, 22 of which were identified, representing 13 different proteins.

Modulation of the multisubstrate specificity of Thermus maltogenic amylase by truncation of the N-terminal domain and by a salt-induced shift of the monomer/dimer equilibrium

The relation between the quaternary structure and the substrate specificity of Thermus maltogenic amylase (ThMA) has been investigated. Sedimentation diffusion equilibrium ultracentrifugation and gel filtration analyses, in combination with the crystal structure determined recently, have demonstrated that ThMA existed in a monomer/dimer equilibrium. The truncation of ThMA by removing the N-terminal domain, which is composed of 124 amino acid residues, resulted in the complete monomerization of the enzyme (ThMADelta124) accompanied by a drastic decrease in the activity for beta-cyclodextrin (beta-CD) and a relatively smaller reduction of the activity for starch. Despite the overall low activity of ThMADelta124, the activity was higher toward starch than beta-CD, and the ratio of the specific activities toward these substrates was approximately 100 fold higher than that of wild-type ThMA. Furthermore, the addition of KCl to wild-type ThMA shifted the monomer/dimer equilibrium toward the monomer. In the presence of 1.0 M KCl, the relative activity of ThMA toward beta-CD decreased to 74%, while that for soluble starch increased to 194% compared to the activities in the absence of KCl. Thus, the ThMA monomer and dimer are both inferred to be enzymatically active but with a somewhat different substrate preference. Kinetic parameters of the wild-type and truncated enzymes also are in accordance with the changes in their specific activities. We thus provide evidence in support of a model, which shows that the relative multisubstrate specificity of ThMA is influenced by the monomer/dimer equilibrium of the enzyme.

[Hepatectomy in intrahepatic lithiasis]

STUDY AIM

The aim of this study was to report the immediate results of a series of 65 hepatic resections for hepatolithiasis performed in Vietnam.

PATIENTS AND METHOD

From 1986 to 1998, 44 men and 21 women (mean age: 40 years) underwent hepatic resection for hepatolithiasis. Fourty patients had previously undergone one or several operations for hepatolithiasis. The procedure was performed on emergency in 25 patients. Indications for hepatic resection were: angiocholitis and liver abscess in 22 cases, stones closely inserted in the biliary duct in 20 cases, hemobilia in 12 cases, stones located above a biliary stricture in 8 cases and stones associated with a postoperative biliary fistula in 3 cases. Liver resections (minor in 61 patients, including 55 left lobectomies, and major in 4 patients) were performed through transhepatic approach according to the Ton That Tung technique and followed by an external biliary drainage with a Kehr tube.

RESULTS

There were 6 postoperative deaths (9%), 3 due to septic shock, 2 to cachexia, and 1 to liver failure. The 15 patients with complications recovered with conservative therapy. Bile infection was present in 93%, mostly with Escherichia coli and Enterobacter. Pigmented stones were usually found.

CONCLUSION

Vietnam is a country with high incidence of hepatolithlasis. Hepatic resection is an adequate treatment for localized intrahepatic bile duct stones when the involved segment including biliary strictures and calculi can be completely removed. The procedure may be performed on emergency for liver abscess, or hemobilia.

Symptoms associated with oophorectomy and tamoxifen treatment for breast cancer in premenopausal Vietnamese women

There are very few data about the efficacy and toxicity of adjuvant systemic therapies for breast cancer in non-western populations. In 1993 in Vietnam we began a randomized controlled clinical trial on premenopausal women with operable breast cancer comparing adjuvant surgical oophorectomy plus tamoxifen with observation and this same combined hormonal treatment on recurrence. We evaluated the symptoms reported at regular follow-up visits by the first 482 premenopausal women entered in this clinical trial and treated with surgical oophorectomy plus tamoxifen or observation. Hot flash frequency and intensity, vaginal discharge, and genital pruritus were the only symptoms to occur more frequently in oophorectomy and tamoxifen-treated subjects. Seventy-seven percent of oophorectomy/tamoxifen subjects reported grade 1 or more and 44% grade 2 or more hot flash frequency symptoms in the first 12 months, versus 9% and 1% of observation subjects, respectively. Twenty percent of oophorectomy/tamoxifen subjects had grade 2 or greater intensity of hot flashes some time in the first 12 months versus 0% in observation subjects. Through three years, vasomotor symptoms were reported more frequently in oophorectomy/tamoxifen-treated women (in 23% vs. 3% at three years, mostly grade 1 toxicities). While noted and persistent vasomotor symptoms were found with oophorectomy plus tamoxifen in this population of Vietnamese women, these were of lower grades and tolerable. This adjuvant treatment may be widely accepted if it is demonstrated to be effective in this population.

The use of a water extract from the bark of Choerospondias axillaris in the treatment of second degree burns

Burns are common in Vietnam, and because of economic constraints and limited resources for the import of appropriate treatments, the health authorities are obliged to rely on traditional herbal remedies. It is therefore essential to evaluate current drugs, one of which is the water extract of the bark of the tree Choerospondias axillaris. It has been used for many years in the Vietnam-Sweden hospital at Uong Bi in northern Vietnam. We assessed the efficacy of the remedy in an open, randomised controlled clinical trial, in which 20 patients with second degree burns were treated with the extract of the Choerospondias axillaris and 19 with saline gauze. The mean healing time was significantly shorter for patients treated with Choerospondias axillaris (11 days) compared with patients treated with saline gauze (17 days) (p < 0.01), and the number of wound infections was significantly lower in the Choerospondias axillaris group (7/20 compared with 16/19, p = 0.003). The bark extract was easy to apply and additional wound care was not usually necessary, while the treatment with saline gauze was laborious for both patients and staff and was much more expensive. The extract from Choerospondias axillaris is a convenient treatment for second degree burns in both children and adults.

Ion Chromatographic determination of trace anions and cations in high-purity water

An ion chromatographic measuring system for the off-line and on-line determination of some trace anions and cations in high-purity water is presented. The ng/L level of anions and cations in 20-130 mL high-purity water can be analyzed after preconcentration on ion exchange columns. The concentrated solutes are eluted by eluents from the trap column and separated using a Dionex analytical column. The quantification of each ion is achieved using the suppressor technique and conductivity detector. The influence of various parameters on the results is discussed. The detection limits of cations and anions are between 10 and 30 ng/L for chloride, bromide, nitrate, phosphate, sulphate, sodium, ammonium, potassium, magnesium and calcium ions.

Rapid destructive arthritis of the shoulder

Rapid destructive arthritis of the shoulder, although uncommon, has received much attention in the recent medical literature. It has been described by several authors under varied names: hemorrhagic shoulder of the elderly, Milwaukee shoulder syndrome, rapid destructive arthritis of the shoulder, apatite-associated destructive arthritis and idiopathic destructive arthritis of the shoulder. This particular form of arthritis affects mainly elderly patients, predominantly women, with limited pain, rotator cuff tear, joint instability, voluminous mildly inflammatory, blood-stained effusion, basic calcium phosphate crystals, and marked joint and bone destruction.

[Ultrasonographic diagnosis of appendicitis. Value and limitations]

Appendicitis is a frequently encountered surgical emergency which can be diagnosed by clinical and laboratory criteria. But there are some atypical cases that ultrasound can help to diagnose. From April the 9th 1992 to April the 11th 1993, we have examined by ultrasound 465 patients entered in our hospital for right lower quadrant pain. 190 patients have been diagnosed as appendicitis and operated (true positive = 124 cases, false negative = 54 cases and false positive = 12 cases). 275 patients have been diagnosed as negative and they are not operated (true = 273 cases, false positive = 2 cases). So in our study, the sensitivity is 70%, the specificity is 95% and the accuracy is 85%. Our scientific report has the objective to show the usefulness and the limits of ultrasound in the diagnosis of appendicitis.

Real time dose rate and LET spectrum aboard MIR station during 1992

Since the end of July 1992, the NAUSICAA system, a low gas pressured tissue equivalent proportional counter, recorded in real time the dose equivalent rate, the absorbed dose rate, the quality factor and the Linear Energy Transfer spectra, aboard the Russian orbital station MIR. The results since the ANTARES mission are presented. Some parameters like the proton flux, the previous solar cycles, the location of the NAUSICAA system inside the station and the South Atlantic Anomaly crossing seem to have an influence on these results. The total dose equivalent (H) during the ANTARES mission (between 1992 July the 30th and August the 10th) was 12 mSv and the total absorbed dose (D) 6.4 mGy with a quality factor (Q) equal to 1.9. The NAUSICAA system gives a good knowledge of LET spectra for the first time in space dosimetry.

Klippel-Feil syndrome: patterns of bony fusion and wasp-waist sign

Cervical spine radiographs of 33 patients with Klippel-Feil syndrome were studied for patterns of bony fusion and presence of wasp-waist sign. Five patients were found to have the classic features of massive cervical fusion. Two patients with two adjacent levels of bony fusion showed a wasp-waist sign. Fusion at one level of the cervical spine accounted for 26 remaining cases. The wasp-waist sign was observed in 14 of the cases in which there was complete vertebral interbody fusion, making this finding a valuable radiologic sign. Partial anterior or posterior vertebral interbody fusion, or isolated fusion of the neural arch, however, may or may not be associated with the wasp-waist sign. Klippel-Feil syndrome, easy to recognize when presenting with classic features or when associated with the wasp-waist sign, may be confused with a variety of other entities.

The radiologic spectrum of abnormalities of the foot in diabetic patients

Radiologically visible lesions in the feet of patients with long-standing diabetes mellitus are common and varied. They include osteoporosis, osteosclerosis, osteolysis, juxta-articular defects of the cortical bone, ischemic bone necrosis, new bone formation, spontaneous fracture and subluxation, and neuropathic arthropathy. These manifestations result from diabetic angiopathy and neuropathy and usually are complicated by infection. In this review the author describes these protean radiologic features in light of their pathogenesis and discusses the diagnostic problems encountered.

[The clinico-parasitological examination of a focus of intestinal nematodiases in Ha-Shon-Bin Province in the People's Republic of Vietnam and an analysis of 5 medamine treatment schemes]

An intensive focus of intestinal nematodiases in a foothill province of Vietnam is described; the incidence of ascaridiasis there was found to be 81.8%, trichuriasis 78.1%, and ankylostomiasis 12.3%. Polyinvasions were detected in more than 80% of the examinees. Analysis of five schemes of medamin therapy, used in three provinces in 595 patients with ascaridiasis, 490 ones with trichuriasis, and 323 ones with ankylostomiasis has shown that the treatment efficacy was reducing with the invasion intensity augmentation. In ascariasis the 3- and 5-day therapeutic schemes were the most effective, their efficacies being 68.4 and 82.0%, respectively; in trichuriasis and ankylostomiasis a 3-day scheme was the best, its efficacies being 74.0 and 71.9%, respectively. Retrograde ascarid migration occurred in 1.2% of 595 ascaridiasis patients after medamin therapy.

Quality factor and dose equivalent investigations aboard the Soviet space station MIR

Since Dec 1988, date of the French-Soviet joint space mission "ARAGATZ", the CIRCE device (Compteur Intégrateur de Rayonnement Complexe dans l'Espace) had recorded dose equivalent and quality factor inside the MIR station (380-410 km, 51.5 degrees). After the initial gas filling two years ago, the low pressure tissue equivalent proportional counter is still in good working conditions. Some results of three periods, viz Dec 1988, Mar-Apr 1989 and Jan-Feb 1990 are presented. The average dose equivalent rates measured are respectively 0.6, 0.8 and 0.6 mSv/day with a quality factor equal to 1.9. Some detailed measurements show the increasing of the dose equivalent rates through the SAA and near polar horns. The real time determination of the quality factors allows to point out high LET (Linear Energy Transfer) events with quality factors in the range 10-20.

A rare bone tumor in an unusual location: osteoblastoma of the vertebral body

Most osteoblastomas involve the posterior elements alone, or both the posterior elements and the vertebral bodies. Osteoblastomas confined in the body of the vertebrae are very rare. Spinal osteoblastomas are associated with localized pain in about 80% of cases and neurological deficits in 25% to 50% of cases. Nearly half of lumbar and thoracic osteoblastomas demonstrate coexistent scoliosis with the convex side away from the involved side of the vertebrae.

Unusual feature of soft-tissue calcification in chronic renal failure: tumoral calcification

Two cases of massive calcification in dialysed patients are described with computerized tomography correlation: one in the abdominal/pelvic cavity, which is a rare location, and the other in the abdominal wall. The cause of these calcified deposits is multifactorial and complex. Usually painless, they may cause restriction of joint movement by virtue of their bulky size.

Freiberg's disease in diabetes mellitus

We evaluated a total of 13 cases of Freiberg's disease in patients aged 47-77 years collected over an 8-year period. Seven were associated with diabetes mellitus and one with chronic renal failure; the remainder had no underlying disease. Atrophy of intrinsic small foot muscles secondary to neuropathy, which is prevalent in diabetes mellitus, may play a part in the development of Freiberg's infraction.

A rare cause of splenic infarct and fleeting pulmonary infiltrates: polyarteritis nodosa

A rare multi-system disease with an incidence of about 5/million per year, polyarteritis nodosa (PAN) occasionally may cause splenic vasculitis, usually at arteriole bifurcations, leading to multiple systemic infarcts with extensive confluent systemic necrosis. PAN may also be a cause of fleeting patchy pulmonary infiltrates or pulmonary nodular lesions. The diagnosis is usually difficult and delayed because the clinical manifestations are varied and depend on the site and the extent of the arterial involvement.

A rare cause of laryngeal distress: chondrosarcoma of the larynx

Laryngeal chondrosarcomas are much less aggressive lesions than chondrosarcomas that arise elsewhere in the body. Two cases of chondrosarcoma of the larynx encountered during a seven year period are presented, with a review of the literature. Computed tomographic (CT) and magnetic resonance imaging (MRI) findings are described. The MRI findings of laryngeal chondrosarcoma are compared to those of cartilaginous tumors elsewhere in the body. The differential diagnosis, prognosis, and treatment of laryngeal chondrosarcomas are discussed.

Real time quality factor and dose equivalent meter "CIRCE" and its use on-board the Soviet orbital station "MIR"

During the French-Soviet space mission "Aragatz," the experiment CIRCE (Compteur Integrateur de Rayonnement Complexe dans l'Espace) recorded the dose rate and quality factor values inside the MIR station. This paper presents results obtained with a new active dose equivalent meter based on microdosimetric techniques and using a low pressure tissue equivalent proportional counter. In terms of lineal energy CIRCE device works in the 0.2-1200 keV micrometer-1 range in tissue. Preliminary studies were performed in photon, neutron and heavy ion beams, and in the real stratosphere cosmic radiation field. Long term measurements on-board MIR station from December 1988 to April 1989 gave an average quality factor value equal to 1.9 +/- 0.3. Through the South Atlantic Anomaly (SAA), the quality factor was equal to 1.4. The temporal orbital variations of the dose rates and quality factors have been established in space dosimetry for the first time.

Subcutaneous soft tissue densities: a computed tomography indicator of severe pancreatitis

Twenty patients with known acute pancreatitis had 50 computed tomography studies. Those with severe pancreatitis showed streaky and fluffy soft tissue densities in the flanks and some in the gluteal regions. The appearance and disappearance of this finding correlates with the extravascular movement of fluid due to severe pancreatic inflammation.

[The clinical efficacy of and tolerance for lariam (mefloquine) in tropical malaria in the south of the Socialist Republic of Vietnam]

The study was performed in the area of distribution of tropical malaria resistant to 4-aminoquinolines (Vietnam) on 30 patients receiving lariam (mefloquine). The results were compared to the standard therapy with quinine and fansidar. They indicate a high efficacy of and a good tolerance to the drug tested. The use of lariam leads to a more rapid (as compared to the standard treatment) elimination of parasitemia and complete eradication of the disease relapses. The findings make it possible to recommend lariam for the prevention and treatment of tropical malaria.

Acute interstitial nephritis associated with cefotetan therapy

We report a case of acute interstitial nephritis associated with cefotetan therapy. Cefotetan should be considered a potential cause of acute renal failure in patients who develop rash, eosinophilia, and fever in association with an acute deterioration of renal function.

"Idiopathic destructive arthritis" of the shoulder: a still fascinating enigma

Idiopathic destructive arthritis of the shoulder is uncommon, and all previous reports appeared in the nonradiologic literature. The clinical, radiological, and laboratory findings are described. This rare form of rapidly destructive arthritis of the shoulder bear resemblance to several neuropathic-like arthropathies, and its etiopathogenesis is still unclear.

[Clinico-parasitological research in a focus of intestinal nematodiasis in Habak Province (the Socialist Republic of Vietnam) and the efficacy of medamine treatment in these infestations]

The authors described the focus of intestinal nematodiasis in Vietnam with the rate of infestation on the average 74.6% for ascaridiasis, 30.8 for trichocephaliasis and 20.2% for ancylostomiasis. The high rate of the geohelminthic infestation was related with the use of untreated feces for the vegetables rearing. The clinical symptoms of intestinal nematodiasis were featured by dyspepsia, pain and asthenoneurotic syndromes. The first field trials of mediamine treatment were performed for 267 patients in the high-intense foci of intestinal nematodiasis in the tropics. In trichocephaliasis patients therapeutic efficacy of the drug was 74%, in ancylostomiasis patients it was 71.9, in ascaridiasis patients 68.4%. Retrograde ascarid migration was noted in two patients.

The pelvic digit: CT correlation and review of the literature

Four additional cases of the developmental anomaly known variously as pelvic "ribs" or "digits" are presented with CT correlation in three cases. Comparison is made with the 12 cases reported in the literature, and their differential diagnosis is discussed.

Modification of a Dionex System 12 ion chromatograph for sequential determination of the main components in atmospheric precipitation

A modification of a Dionex System 12 ion chromatograph is described which enables organic anions (acetate and formate), inorganic cations (ammonium, sodium and potassium) and inorganic anions (chloride, nitrate and sulphate) to be determined sequentially in one measuring procedure. The modified instrument consists of a programmable controller unit, a conductimetric meter, two conductimetric detectors of the Dionex System 12 ion chromatograph, the HPIC-AS4A and HPIC-CS3 modern separation units, AMMS-1 and CMMS-1 micro-membrane suppressor columns, a unique system of valves from Dionex and two dual pumps from Biotronik. The limits of detection are between about 1 and 3 micrograms/l for chloride, nitrate and sulphate and between about 2 and 10 micrograms/l for acetate, formate, ammonium, sodium and potassium. The reliability of the method was demonstrated by analysing two NBS simulated rain water Standard Reference Materials. Some examples are given of the application of the method to the sequential determination of the main precipitation components in typical samples from urban and rural regions of the F.R.G. The ion concentrations varied between about 0.02 and 300 mg/l.

Detection of ionizing radiations with the SOS Chromotest, a bacterial short-term test for genotoxic agents

The effects of 3 types of ionizing radiation, gamma-rays, neutrons and accelerated alpha-particles, were examined using the SOS Chromotest, a bacterial colorimetric assay for genotoxic agents based on the measurement of the SOS response in Escherichia coli. The SOS Chromotest appeared to be a sensitive and simple assay to detect quantitatively these radiations as well as their biological effects. The range of adsorbed doses for which induction was observed was similar for the 3 types of radiation, the minimum inducing doses being in the order of 2.5-5 Gy. We discuss the possible use of these observations to study the molecular action of radiations and to compare their genotoxic effects with those of chemicals.

The role of free fatty acids in hypoxia-induced injury to renal proximal tubule cells

Phospholipase activation with resulting phospholipid breakdown and lipid byproduct accumulation may play a critical role in hypoxic cell injury. To explore this role, mildly hypoxic rabbit renal proximal tubules (PT) in suspension were treated in vitro with exogenous phospholipase A2 (PLA2). This treatment produced severe tubule cell injury measured by alterations in tubule cation homeostasis, respiratory rates, and adenosine nucleotide metabolism. This injury was associated with loss of the major membrane phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), with accumulation of lipid byproducts, lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), and free fatty acids (FFA). Addition of fatty acid-free bovine serum albumin (BSA) to PTs reduced markedly FFA levels and improved significantly derangements in metabolic parameters of hypoxic PTs treated with exogenous PLA2, suggesting that FFA accumulation was a critical factor in this injury process. Effects of increasing durations of hypoxia (30, 45, and 60 min) with or without reoxygenation recovery demonstrated increased FFA levels, especially polyunsaturated FFA, which correlated better with the degree of hypoxic injury than alterations in membrane phospholipid and lysophospholipid levels. PTs undergoing hypoxia and reoxygenation recovery exposed to BSA were not protected. Although 60 min of hypoxia with 60 min reoxygenation produced accumulation of FFA to levels nearly identical to those seen in hypoxic PTs treated with exogenous PLA2 and BSA, with a similar distribution of various FFA species, hypoxia/reoxygenation produced a more severe degree of cell injury than that observed with hypoxia plus exogenous PLA and BSA.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of adenosine triphosphate in phospholipase A2-induced rabbit renal proximal tubule cell injury

The pathogenesis of ischemic renal tubular cell injury involves a complex interaction of different processes, including membrane phospholipid alterations and depletion of high-energy phosphate stores. To assess the role of membrane phospholipid changes due to activation of phospholipases in renal tubule cell injury, suspensions enriched in rabbit renal proximal tubule segments were incubated with exogenous phospholipase A2 (PLA2). Exogenous PLA2 did not produce any significant change in various metabolic parameters reflective of cell injury in control nonhypoxic preparations despite a significant decrease in phosphatidylethanolamine (PE) and moderate increases in lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE). In contrast, exogenous PLA2 treatment of hypoxic tubules resulted in a severe degree of cell injury, as demonstrated by marked declines in tubule K+ and ATP contents and significant decreases in tubule uncoupled respiratory rates, and was associated with significant phospholipid alterations, including marked declines in phosphatidylcholine (PC) and PE and significant rises in LPC, LPE, and free fatty acids (FFA). The injurious metabolic effects of exogenous PLA2 on hypoxic tubules were reversed by addition of ATP-MgCl2 to the tubules. The protective effect of ATP-MgCl2 was associated with increases in tubule PC and PE contents and declines in LPC, LPE, and FFA contents. These experiments thus indicate that an increase in exogenous PLA2 activity produces renal proximal tubule cell injury when cell ATP levels decline, at which point phospholipid resynthesis cannot keep pace with phospholipid degradation with resulting depletion of phospholipids and accumulation of lipid by-products. High-energy phosphate store depletion appears to be an important condition for exogenous PLA2 activity to induce renal tubule cell injury.

Comparison of the toxicity of the radiocontrast agents, iopamidol and diatrizoate, to rabbit renal proximal tubule cells in vitro

Radiographic contrast agent-induced acute renal failure is an increasingly recognized clinical event. Multiple factors have been implicated in its development. Recent experiments have demonstrated that sodium diatrizoate, a common ionic radiocontrast agent, is moderately toxic to proximal tubule cells in vitro, and that this toxicity is enhanced by hypoxia. In this study, we compare toxicities of the nonionic radiocontrast agent, iopamidol, and the commonly used ionic contrast agent, diatrizoate. Suspensions enriched in proximal tubule segments were exposed for 82.5 min to 10 or 25 mM diatrizoate or 10 or 25 mM iopamidol with or without 22.5 min or 30 min of hypoxia. Cell viability parameters, including basal and uncoupled respiratory rates, tubule cell potassium and calcium levels and cell ATP content were measured. No consistent differences in tubule viability parameters were observed between tubule suspensions exposed to 10 mM concentrations of the radiocontrast agents during either oxygenated or hypoxic conditions. Under oxygenated conditions, both 25 mM iopamidol and diatrizoate exposure produced greater metabolic alterations in renal tubules than control conditions, but the effects were not statistically significant. With concomitant hypoxia, the alterations after 25 mM diatrizoate exposure were significantly greater than those seen after exposure to 25 mM iopamidol. Iopamidol had less of a detrimental effect on renal tubule potassium content and both basal and uncoupled respiratory rates than that of diatrizoate under these conditions. Thus, diatrizoate is more toxic to rabbit renal proximal tubule cells than iopamidol in vitro, and this difference in toxicity is enhanced by hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

High energy phosphates, phospholipids, and calcium in ischemic renal tubular cell injury

Substantial data is available supporting critical roles for high energy phosphates, calcium, and phospholipids in ischemic cell injury. Although it has been proposed that one of these compounds may be most critical and defines the "final common pathway" for lethal cell injury, it is more accurate to define the pathogenesis of ischemic cell injury as the simultaneous derangement of several critical metabolic process which act in concert to produce a cascade of events that finally lead to plasma and subcellular membrane dysfunction incompatible with the maintenance of cell viability and integrity. As detailed in Figure 1, a tentative scheme is proposed interrelating high energy phosphate depletion, cellular calcium derangements, and membrane phospholipid degradation and loss. Ischemia directly leads to declines in the rate of oxidative phosphorylation due to a lack of oxygen availability. A fall in cellular ATP levels develops. Ischemia also promotes a redistribution of intracellular calcium pools and results in phospholipase activation and phospholipid degradation. When phospholipid degradation occurs concomitantly with a decline in high energy phosphate levels, phospholipid synthesis cannot keep pace with phospholipid degradation and net membrane phospholipid loss occurs. An increase in plasma membrane calcium permeability develops and the influx of calcium down its electrochemical gradient from extracellular to intracellular spaces occurs. This calcium is taken up and sequestered in mitochondria and causes further alterations in mitochondrial structure and function, leading to further declines in cellular ATP content.(ABSTRACT TRUNCATED AT 250 WORDS)

Ring sequestrum: radiographic characteristics of skeletal fixation pin-tract osteomyelitis

Major pin-tract infections are a potentially dangerous complication associated with the use of skeletal transfixation pins. The presence of a characteristic radiographic finding, the ring sequestrum, is virtually diagnostic of this abnormality. The clinical and radiographic findings in seven patients treated for this complication are presented. Thermal necrosis without infection presents as a zone of sclerosis around the tract. A narrow, radiolucent halo may surround the dense bone. When a narrow ring sequestrum is surrounded by a radiolucent halo, there is associated infection.

Cerebro-costo-mandibular syndrome with consanguinity

The cerebro-costo-mandibular syndrome is a rare disorder characterized by unique posterior rib defects, micrognathia, and mental deficiency. The mode of transmission is undetermined. This report describes the first case with documented parental consanguinity as well as hitherto undescribed CT and skeletal findings.