One-day protocol versus two-day protocol in acquisition of scintigraphy with "in vitro" labelled white blood cells for diagnosis of osteoarticular infection

INTRODUCTION

It is difficult to determine osteoarticular infection and differentiate inflammation from infection with laboratory and imaging procedures (CT, MRI, US). Labelled white-blood-cell scintigraphy (WBCS) is the nuclear medicine test of choice but it takes two days, sometimes finds it difficult to differentiate soft tissue from bone infection and therefore causes interobserver variability, which decreases its specificity.

OBJECTIVE

To demonstrate the usefulness of the one-day protocol with time decay-corrected acquisition in WBCS to diagnose osteoarticular infection and to reduce interobserver variability. The role of SPECT/CT in WBCS in locating the infected focus was also evaluated.

METHODS

110 patients with suspected osteoarticular infection were studied prospectively. Planar images were obtained with time decay-corrected acquisition at 30min, 4h, 8h and 24h. WBCS planar images were grouped in two protocols: One-day protocol: experts evaluated 30min, 4h and 8h images. Two-day protocol: experts evaluated 30min, 4h and 24h images. Both protocols were classified as: SPECT/CT was performed in 72 patients. Kappa index was calculated to evaluate interobserver variability.

RESULTS

Infection was confirmed in 34 cases. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 97.1%, 97.4%, 94.3%, 98.7%, and 97.3% for the one-day protocol and 94.1%, 97.4%, 94.1%, 97.4%, and 96.4% for two-days-protocol. SPECT/CT contributed to diagnosis in 45/50 patients with planar WBCS positive. Kappa index: 0.8 for one-day protocol and 0.79 for two-day protocol, respectively.

CONCLUSION

One-day protocol with time decay-corrected acquisition WBCS and SPECT/CT enables early and accurate diagnosis of osteoarticular infection.

Overexpression of the carbohydrate binding module from Solanum lycopersicum expansin 1 (Sl-EXP1) modifies tomato fruit firmness and Botrytis cinerea susceptibility

Firmness, one of the major determinants of postharvest quality and shelf life of fruits is determined by the mechanical resistance imposed by the plant cell wall. Expansins (EXP) are involved in the non-hydrolytic metabolic disassembly of plant cell walls, particularly in processes where relaxation of the wall is necessary, such as fruit development and ripening. As many carbohydrate-associated proteins, expansins have a putative catalytic domain and a carbohydrate-binding module (CBM). Several strategies have been pursued to control the loss of fruit firmness during storage. Most of the approaches have been to suppress the expression of key enzymes involved in the cell wall metabolism, but this is the first time that a CBM was overexpressed in a fruit aimed to control cell wall degradation and fruit softening. We report the constitutive overexpression of the CBM of Solanum lycopersicum expansin 1 (CBM-SlExp1) in the cell wall of tomato plants, and its effects on plant and fruit phenotype. Overexpression of CBM-SlExp1 increased the mechanical resistance of leaves, whereas it did not modify plant growth and general phenotype. However, transgenic plants showed delayed softening and firmer fruits. In addition, fruits were less susceptible to Botrytis cinerea infection, and the "in vitro" growth of the fungus on media containing AIR from the pericarp of transgenic fruits was lower than controls. The possibility of overexpressing a CBM of a fruit-specific expansin to control cell wall degradation and fruit softening is discussed.

Analysis of the carbohydrate-binding-module from Fragaria x ananassa α-L-arabinofuranosidase 1

α-L-arabinofuranosidases (EC 3.2.1.55) are enzymes involved in the catabolism of several cell-wall polysaccharides such as pectins and hemicelluloses, catalyzing the hydrolysis of terminal non-reducing α-L-arabinofuranosil residues. Bioinformatic analysis of the aminoacidic sequences of Fragaria x ananassa α-L-arabinofuranosidases predict a putative carbohydrate-binding-module of the family CBM_4_9, associated to a wide range of carbohydrate affinities. In this study, we report the characterization of the binding affinity profile to different cell wall polysaccharides of the putative CBM of α-L-arabinofuranosidase 1 from Fragaria x ananassa (CBM-FaARA1). The sequence encoding for the putative CBM was cloned and expressed in Escherichia coli, and the resultant recombinant protein was purified from inclusion bodies by a Nickel affinity chromatography under denaturing conditions. The refolded recombinant protein was then subjected to binding assays and affinity gel electrophoresis, which indicated its ability to bind cellulose and also high affinity for homogalacturonans.

Numb chin syndrome as a manifestation of jaw metastasis diagnosed in a bone scan

In many cases, numb chin syndrome (NCS) may represent a banal pathology. However, as it can be associated with malignant processes, its presence should alert the clinician of a possible occult disease. In patients already diagnosed with cancer, it often represents an ominous sign that indicates poor prognosis, due to the rapid progress of the disease. The case is presented of a 62-year-old man diagnosed with synchronous lung and bladder cancer, who suddenly complained of numbness in the chin. The bone scan confirmed the suspicion of metastastic bone disease, and the patient died two months after the appearance of this sign.

Condom use among female sex workers and their non-commercial partners: effects of a sexual risk intervention in two Mexican cities

The purpose of this study was to examine whether a brief behavioural intervention promoting condom use among female sex workers (FSWs) and their clients had the added benefit of increasing condom use among FSWs and their steady, non-commercial partners (e.g. husbands, boyfriends). Participants were 362 FSWs, aged ≥18 years, living in Tijuana or Ciudad Juarez, Mexico, who received a behavioural intervention to promote condom use with clients. Repeated-measures negative binomial regression was used to assess FSWs' condom use with steady partners versus clients across time. Results showed that FSWs engaged in unprotected sex with steady partners more than with their clients, and that the intervention changed FSWs' condom use with clients but not their steady partners. HIV-prevention interventions for FSWs should promote consistent condom use across partner type. Targeting couples rather than individuals may also be necessary.

Cloning of FaPAL6 gene from strawberry fruit and characterization of its expression and enzymatic activity in two cultivars with different anthocyanin accumulation

The accumulation of anthocyanin pigments is one of the most important traits that turn strawberry fruit attractive to consumers. During ripening, strawberry fruit color development is associated to anthocyanin synthesis through the phenylpropanoid pathway. Phenylalanine ammonia-lyase (PAL) is a key enzyme in this pathway, having a determining role in strawberry fruit quality. In this work, we studied the level of anthocyanins during fruit ripening of two cultivars that differ in color development (Camarosa and Toyonoka). Toyonoka showed a lower anthocyanin accumulation that was limited to external fruit tissue, while Camarosa accumulated higher amount of anthocyanins in both internal and external sections. In addition, we cloned a full-length gene (FaPAL6) and analyzed its expression in different strawberry plant tissues. The expression of this gene is fruit specific, and increases during fruit ripening in both cultivars along with anthocyanin accumulation. The mRNA level of FaPAL6 was higher in Camarosa. PAL enzyme activity increased at similar rates in both cultivars at early ripening stages, but at the end of ripening PAL activity diminished in Toyonoka while it rose markedly in Camarosa. PAL activity was higher in internal fruit tissue, showing no correlation with anthocyanin level of the same section in both cultivars. The higher FaPAL6 expression and activity detected in Camarosa could be associated to the enhanced anthocyanin accumulation found in this cultivar.

Changes in cell wall composition of three Fragaria x ananassa cultivars with different softening rate during ripening

Fleshy fruit soften during ripening mainly as a consequence of solubilization and depolymerization of cell wall components. We have performed a comparative study of the polysaccharide content of fruit cell walls during final steps of development and ripening of three strawberry (Fragaria x ananassa Duch.) cultivars with different softening rates. The three chosen varieties showed very different firmness; Camarosa was the firmest, Toyonaka the softest, and Pajaro intermediate between them. Cell walls were extracted, quantified and fractioned by sequential extraction to obtain particular subclasses of cell wall polymers. Cell wall content diminished during the process in the three cultivars. Differences among cultivar cell wall contents were detected only in immature stages. The amount of water soluble polymers (WSP) increased in all cultivars from small green (SG) to white (W) stage, although from the W to 100% red (100%R) stage the WSP remained constant in Camarosa and Pajaro and decreased in Toyonaka. On the contrary, the hydrochloric acid-soluble pectins (HSP) decreased during ripening of all the cultivars analyzed. Camarosa had the largest amount of HSP, but there were no differences between Pajaro and Toyonaka. The amount of hemicellulosic polysaccharides and cellulose also decreased in the three cultivars. Camarosa had the highest amounts of both polysaccharides while Toyonaka had the lowest at immature stages, but there were no differences among cultivars at 100%R stage. WSP showed depolymerization only in Toyonaka cultivar, while HSP showed depolymerization in Pajaro and Toyonaka cultivars. A slight depolymerization was observed in hemicelluloses extracted from any of three cultivars.

Characterization of peroxidase-mediated chlorophyll bleaching in strawberry fruit

Peroxidase (POX) from strawberry fruits was analyzed for its capacity to bleach chlorophyll. The partially purified enzyme preperation catalyzed the bleaching of chlorophylls and their derivatives in the presence of H(2)O(2) and phenolic compounds. The optimal reaction conditions were 35 degrees C, pH 5.2 and ionic strength equal to 0.2. The maximum activity was observed at 1 mM of H(2)O(2), while higher concentrations inhibited enzyme activity. Compounds with a high affinity to the heme group, radical scavengers and reducing agents, showed an inhibitory effect. Phenolic compounds such as umbelliferone, naringenin and p-substituted monophenols acted as cofactors. Instead, other phenolic compounds tested such as caffeic acid, catechin, ellagic acid, esculin and quercetin inhibited the activity of POX on chlorophylls. Phenolic compounds extracted from strawberry fruits showed an inhibitory effect on POX-chlorophyll bleaching activity, although this effect decreased markedly during ripening. POX showed higher affinity for compounds derived from chlorophyll a than from chlorophyll b, and the enzyme preferentially degraded chlorophyll derivatives with the Mg(2+) ion present and the phytol group removed. The POX-chlorophyll bleaching activity was found in all ripening stages from small green to ripe, the highest activity corresponding to large green fruits.

The modulation of coupled relaxation in porous media

This work investigates the effects of modulation of the transverse and longitudinal relaxation of the surface-fluid/pore-fluid spin system in porous media. Important new NMR well logging applications identify pore fluids by varying the CPMG T(2) pulse spacing to discriminate on the basis of fluid diffusivities in applied and local static magnetic field gradients. However, anomalous laboratory CPMG T(2) results have been reported repeatedly over 25 years for various porous media filled with a single fluid. In relatively large pores, at near bulk conditions, the transverse relaxation of diffusing molecular spins should be proportional to the square of the CPMG pulse spacing tau, the susceptibility contrast at the pore wall and the applied gradient. Observed is a markedly linear tau dependence that saturates at a plateau for large tau. The effect is not quadratic in applied gradient or susceptibility. For large pores, the tau dependence and the saturation value are proportional to the surface-to-volume ratio of the pores. This is in distinct contrast to the behavior observed by Borgia, Brown and Fantazzini for systems with much smaller pores at higher magnetic fields. The large-pore anomalous behaviors can be explained as a modulation of the exchange between surface-fluid and pore-fluid spins, such as observed by Luz and Meiboom in 1963 for water enriched with quadrupolar 17O. Scalar coupling of the solid-surface spins to the fluid-surface spins was postulated by Kleinberg, Kenyon and Mitra as a dominant relaxation mechanism for the surface fluid. The CPMG tau effect can be described as the modulation of the exchange coupling by the CPMG pi pulses, which mix the magnetizations between the exchanging, strongly coupled spin systems of the pore-fluid and the surface-fluid, which is, in turn, weakly coupled by scalar or pseudo-scalar interactions to the fast-relaxing solid surface.

Characterization of Metal Complexation in Multiligand Systems with Lanthanide Luminescence

The effectiveness of an Eu3+ luminescence technique to describe metal complexation reactions in humic substances was evaluated. The molecular uncertainties intrinsic to humic substances were circumvented by using polyacrylic acid (PAA) and polyvinylsulfonic acid (PVS) as probes. An adequate determination of the Eu3+-citrate affinity constant suggested that this technique could potentially be used to characterize metal binding reactions in polyelectrolytes. Various mixtures of PAA and PVS were then evaluated. The commonly adopted assumption of a single metal binding environment in those systems proved ineffective and resulted in a misleading representation of the Eu-PAA binding isotherm. Our evidence indicates that prior knowledge about the number of binding environments, as well as their relative contribution to the overall sorption, is needed to describe metal binding on humic substances appropriately through this approach. The effect of metal competition on Eu3+ binding by a mixed polymer system (1:1 PAA:PVS) was also ascertained. The affinity series obtained (Cu2+ > Pb2+ >> Cd2+ >/= Co2+ congruent with Mg2+ congruent with Ni2+ > Ca2+) was similar to that frequently observed in humic substances, which reinforces the utility of these polymers as their surrogates in metal sorption studies. Copyright 1998 Academic Press.

Influence of monovalent cations on yeast cytoplasmic and vacuolar pH

The effects of monovalent cations on the internal pH of yeast were studied. Our former procedure was modified, inducing maximal alkalinization of the cells with 100 mM-NH4OH instead of Tris base. The pH values were lower than reported before (Peña et al., J. Baceteriol. 1995 177, 1017-1022). With glucose as substrate, the internal cytoplasmic pH reached higher values when incubating at an external pH of 6.0, as compared to pH 4.0. Monovalent cations added approximately 5 min after glucose produced a further increase in the internal pH, which was higher at a previous incubation pH of 4.0 than that observed at pH 6.0. The selectivity of the changes followed a similar order to that of the transport system for monovalent cations. When incubating cells with glucose for more than 30 min, the initial changes of the internal pH appeared to be regulated by the cell. However, under the fluorescence microscope, it was observed that pyranine, which was confined to the cytoplasm during the first 15 min, was progressively concentrated in the vacuole. By studying the fluorescence changes of cells electroporated and then incubated with glucose or glucose plus potassium, we could follow the internal pH of this organelle, obtaining values within the range reported by other authors. Also, in cells preincubated with glucose for 60 min, and electroporated afterwards, the fluorescence of pyranine, which only entered the cytoplasm, allowed us to measure the pH of this compartment, showing that it was more alkaline than the vacuole. Moreover, the cytoplasmic pH increased upon addition of glucose or potassium. The vacuolar pH, on the other hand, increased upon addition of potassium after glucose, but decreased upon addition of glucose. In addition, incubation of the cells with glucose with or without pyranine produced vesiculation of the vacuole.

[Ebola: "a fatal syndrome"]

No other clinical entity has attached more attention now-a-day than those precipitated by the infection with a Hemorrhagic Fever Virus. Potentially caused by Arena, Bunya, Flavi, and Filoviradae, only the latter has had such a major impact throughout the world. Two major genuses have been recognized since they become evident for the first time in 1967, the single-species Marburg, and the 3-species-Ebola (E. zaire, sudan and reston). With the exception of the 2 outbreaks of E. reston (Washington, USA 1989-1993), all of them have taken place in Africa, where the virus is still hiding among the wild-life of the Tropical Rain Forest. Currently (in April 1995) the reemergence of Ebola virus has once more proven its fatality, leaving around 170 deaths in Zaire, 250 miles from its capital, Kinshasa. There is worldwide alert, sponsored by the CDC in Atlanta, the World Health Organization and the authorities in Zaire regarding its potential spreading to naive regions, in and out of Africa. The characteristic clinical picture of a viral hemorrhagic fever has no match. After a 2-21 days incubation period a viral-like illness develops. As days go by, symptoms worsen, and by the 7th day, a severe and diffuse bleeding tendency ensues. The individual's death is the most likely outcome in the great majority of cases. As a lethal virus, without an available treatment and a possible airborne-route of transmission, Ebola virus will always be considered a persistent threat to the global health.