Biological screening of plants of the Venezuelan Amazons

A total of 21 extracts derived from 17 different plant species collected in Venezuelan Amazons have been tested for the following biological activities: cardiovascular activity, brine shrimp lethality, and inhibitory effects on the hydrolysis of glucose-6-phosphate in intact and disrupted microsomes. Eight extracts diminished rat blood pressure with or without changes in heart rate. The fruit extract of Swartzia leptopetala and the leaf and twig extract of Connarus lambertii resulted in death of experimental animals. The majority of extracts (17 extracts) showed significant toxicity against Artemia salina. Concerning the hydrolysis of glucose-6-phosphate, better inhibitory effects were observed in intact microsomes than in disrupted ones for all the extracts, suggesting that these extracts intervene with variable potency in glucose-6-phosphate transport through the microsomal membrane.

In vitro antibacterial activity of glass-ionomer cements

The in vitro antibacterial activity of the glass-ionomer restorative cements Ketac-Cem, Ketac-Bond, Ketac-Silver and Vitrebond was studied in conjunction with 32 strains of five bacteria involved in the development of caries: Streptococcus spp., Lactobacillus spp., Actinomyces spp., Porphyromonas spp. and Clostridium spp. The agar plate diffusion method was used for the cultures, which included a chlorhexidine positive control. All the glass-ionomer cements tested inhibited bacterial growth, but with considerable differences in the scope of their action. Of the four cements, Vitrebond, a resin-modified glass-ionomer cement, was determined to be the most effective bacterial inhibitor.

Laser in situ keratomileusis enhancement after photorefractive keratectomy

OBJECTIVE

To describe the safety, effectiveness, and predictability of laser in situ keratomileusis (LASIK) for correcting residual myopia after primary photorefractive keratectomy (PRK).

DESIGN

A retrospective, noncomparative case series.

PARTICIPANTS AND INTERVENTION

Thirty-six consecutive eyes of 30 patients underwent LASIK after primary PRK. A Multiscan Schwind excimer laser was used for LASIK enhancement.

MAIN OUTCOME MEASURES

Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity, refraction, videokeratography, and complications were determined before and after LASIK retreatment. Follow-up was at least 12 months.

RESULTS

Before LASIK, 11.11% of eyes showed a UCVA of 20/40 or better. This increased to 94.44% 12 months after LASIK. A UCVA of 20/25 or better was achieved in 0% before and in 72.22% after retreatment. Refraction +/-0.5 diopters (spherical equivalent) represented 0% of eyes before and 77.78% of eyes after enhancement. Before LASIK, two eyes had significant haze. Haze remained in these two eyes and appeared in another eye.

CONCLUSIONS

Laser in situ keratomileusis proved to be safe and effective for treating residual myopia after PRK. Care must be taken when considering LASIK retreatment in patients with significant haze after primary PRK.

In-Plant evaluation of a lactic acid treatment for reduction of bacteria on chilled beef carcasses

The effectiveness of a lactic acid treatment consisting of spraying a 4% L-lactic acid solution (55 degrees C at source) on chilled beef carcasses to reduce bacterial populations was tested in a commercial slaughter environment. All carcasses had been treated with a proprietary decontamination treatment composed of a hot water spray followed by a lactic acid spray prior to chilling. Bacterial groups used to indicate reductions included aerobic plate count (APC), total coliform count, and Escherichia coli count, and samples were examined from the brisket, the clod, and the neck regions of 40 untreated and 40 treated carcass sides. Depending on the carcass surface region, APCs were reduced by 3.0 to 3.3 log cycles. Log coliform and E. coli counts were consistently reduced to undetectable levels. The small reductions observed for coliforms are attributable to counts on untreated carcasses already being near the lower detection limit of the counting method. The percentage of samples with detectable numbers of coliforms (positive samples) on untreated carcasses ranged from 52.5 to 92.5%, while 0.0% of the samples collected from treated carcasses contained detectable coliforms. Percent E. coli-positive samples ranged from 7.5 to 30.0% on untreated carcasses and 0.0% after treatment of carcass sides. These results indicate that a hot lactic acid spray with increased concentration and time of application may be effectively implemented for an additional decontamination treatment of chilled beef carcasses prior to fabrication.

[Ocular complications after treatment with intravenous cidofovir for cytomegalovirus retinitis]

PURPOSE

To describe the ocular changes observed in six patients treated with intravenous cidofovir for cytomegalovirus retinitis.

METHODS

We have studied six patients (12 eyes) treated with intravenous cidofovir. A complete ophthalmologic examination was performed before and after each dose during the follow-up period, paying special attention to intraocular pressure changes.

RESULTS

Three cases of non-granulomatous anterior uveitis with good response to conventional treatment were detected. The intraocular pressure decreased after the administration of the two first doses of the drug (p<0.01), and was followed by stabilization of the intraocular pressure with the next doses. In two of the eyes (16.7%), the decrease in the intraocular pressure was more than 50% in comparison to the measurements at the onset of treatment. In three eyes (18.7%), we detected acute anterior uveitis, which responded well to conventional treatment.

CONCLUSIONS

The intravenous administration of cidofovir for the treatment of cytomegalovirus retinitis is associated with important ocular changes that must be carefully observed in the follow-up of these patients.

Effect of initial glucose concentration and inoculation level of lactic acid bacteria in shrimp waste ensilation

Fermentation conditions and microorganisms were determined, based on acid production, glucose concentration as carbohydrate source. Inoculation levels to obtain a stable shrimp waste silage were also determined. Shrimp waste ensilation was an efficient method of preservation, allowing the recovery of chitin and another added-value products such as pigments, proteins and enzymes. From the various lactic acid bacteria tested, Lactobacillus pentosus and Lactobacillus sp. (B2) were the best lactic acid producers, although small quantities of acetic acid were detected in samples inoculated with Lactobacillus pentosus. Therefore B2 was chosen for the analysis of glucose consumption as well as for the determination of optimum inoculation levels. The best results were obtained at 10% (w/w wet basis) and 5% (v/w wet basis) respectively. Presence of starters and initial glucose concentration were critical factors in the fermentation of shrimp waste. High initial glucose and starter concentrations reduced the time and increased the amount of lactic acid produced. The fermentation pattern changed during ensilation from hetero to homofermentative. Shrimp waste ensilation prevented the growth of spoilage microorganisms keeping their microbial counts steady and pH values within the acid region.

[Synovial sarcoma of the tongue. Case report and review of the literature]

Primary synovial sarcoma of the head and neck is a rare entity, nevertheless the literature count on 80 published cases, among them 7 linguals. We contribute with another case: a synovial sarcoma of the tongue, in a 26-year-old man; having a biphasic tumor pattern, with two malignant constituents, epithelial and sarcomatous, similar to other of the same location. Laboratory tests: histochemical, immunohistochemical and electron microscopic were done in order to state the tumor's histogenesis. Our results suggest a pluripotential mesenchymal origin instead of a synovial origin, because the epithelial character of one of the tumor constituents was obviously epithelial.

Decrease in tear secretion and corneal sensitivity after laser in situ keratomileusis

PURPOSE

To evaluate tear secretion and corneal sensitivity after laser in situ keratomileusis (LASIK) for the correction of myopia.

METHODS

In a prospective study, 48 consecutive eyes (24 patients) underwent LASIK to correct myopia ranging from -3.5 to -12.25 diopters. Tear secretion tested by the tear function index and corneal sensitivity tested using the Cochet-Bonnet esthesiometer were evaluated preoperatively and 1 week and 1, 3, 6, and 9 months postoperatively.

RESULTS

Tear secretion and corneal sensitivity after LASIK were reduced during the first 3 months after surgery (p<0.001). Tear secretion returned to its preoperative values only after 9 months. Tear secretion and corneal sensitivity were more depressed in long-term contact lens wearers preoperatively and 6 months after surgery (p<0.05).

CONCLUSION

In the correction of myopia, tear secretion was depressed after LASIK during the first 6 months after surgery.

Investigation of synthetic peptide hormones by liquid chromatography coupled to pneumatically assisted electrospray ionization mass spectrometry: analysis of a synthesis crude of peptide triptorelin

Triptorelin, a synthetic peptide hormone used in the treatment of prostate cancer by means of reduction in the action of male hormone testosterone, is studied here. The synthetic procedure commonly results in unwanted side products that require extensive purification and characterization of the synthesis mixture. The chromatographic separation of triptorelin from the crude mixture was developed by applying the linear solvation energy relationship (LSER) methodology previously developed, to optimize the composition of the mobile phase in order to avoid lengthy empirical optimization procedures. Electrospray ionization mass spectrometry coupled to liquid chromatography (LC/ES-MS) was used to obtain reliable information on the inevitable side products. The knowledge of the identity of these impurities allows fast optimization of the synthetic procedure and also the therapeutic use of triptorelin peptide hormone.

Lactic acid sprays reduce bacterial pathogens on cold beef carcass surfaces and in subsequently produced ground beef

Organic acids have been shown to be effective in reducing the presence of pathogenic bacteria on hot beef carcass surfaces; however, application for decontaminating chilled carcasses has not been fully evaluated. In this study, a postchill, 30-s lactic acid spray (500 ml of 4% L-lactic acid, 55 degrees C) was applied onto outside rounds that had been contaminated with Escherichia coli O157:H7 and Salmonella Typhimurium, subsequent to prechill hot carcass treatments consisting of water wash alone or water wash followed by a 15-s lactic acid spray (250 ml of 2% L-lactic acid, 55 degrees C). The prechill treatments reduced both pathogens by 3.3 to 3.4 log cycles (water wash alone) to 5.2 log cycles (water wash and lactic acid). In all cases, the postchill acid treatment produced an additional reduction in E. coli O157:H7 of 2.0 to 2.4 log cycles and of 1.6 to 1.9 log cycles for Salmonella Typhimurium. The counts of both pathogens remained significantly lower in ground beef produced from the outside rounds that received prechill and postchill acid spray than from those that received a postchill spray only. These data indicate that organic acid sprays may be successfully applied for pathogen reduction in beef carcass processing after the cooler, especially when combined with prechill treatments.

Liquid chromatography-electrospray mass spectrometry of multicomponent peptide mixtures. Characterization of a mixture from the synthesis of the hormone goserelin

In order to separate and characterize the target peptide and the side-product peptide compounds of a synthesis mixture of the peptide hormone goserelin, liquid chromatography coupled to high-flow electrospray ionization mass spectrometry (LC-ES-MS) has been used. Goserelin is an important drug with recognized therapeutical application for palliative treatment of prostatic and breast carcinomas. Stepwise solid-phase peptide synthesis commonly results in unwanted side-products associated with incomplete peptide chains. Consequently, this procedure requires extensive purification and characterization of the final synthesis mixture. The method of linear solvation energy relationships has been applied to optimize the proportion of organic modifier of the mobile phase used in the established LC method. On the other hand, ES-MS has allowed rapid and reliable identification of the target peptide and the other impurities present in the goserelin synthesis products.

Antibacterial activity of four dentin bonding systems

The antibacterial action of bonding systems Gluma 2000, Syntac, Prisma Universal Bond 3, Scotchbond Multipurpose and Prime-Bond was tested against 32 strains of the caries-producing bacteria Streptococcus spp., Lactobacillus spp., Actinomyces spp., Porphyromonas spp. and Clostridium spp. An agar plate diffusion method was used with chlorhexidine as the positive control. Assays were performed in triplicate for each component (primer and adhesive) of the bonding systems. All the adhesives were found to inhibit bacterial growth but with differences in their spectra of action. The sum action of the Scotchbond Multipurpose components were most inhibitory and Prime-Bond was found to be the least effective system.

Antibacterial activity of resin adhesives, glass ionomer and resin-modified glass ionomer cements and a compomer in contact with dentin caries samples

A total of 103 clinical samples of carious dentin were used to study the antibacterial action of different dental resin adhesive materials (Gluma 2000, Syntac, Prisma Universal Bond 3, Scotchbond Multi-Purpose and Prime&Bond 2.0) glass ionomer cements (Ketac-Cem, Ketac-Bond, Ketac-Silver, Ketac-Fil) resin-modified glass ionomer cements (Fuji II LC, Vitremer and Vitrebond) and a compomer (Dyract). The agar plate diffusion method was used for the microbial cultures and a chlorhexidine control. The growth of the caries-producing microorganisms was effectively inhibited by the Vitremer and Vitrebond cements, and to a lesser extent by the Scotchbond Multi-Purpose adhesive system. Overall, there were statistically significant differences in the antibacterial activity of the products tested.

Survival and recovery of viable but noncultivable forms of Campylobacter in aqueous microcosm

Previous studies suggesting that the persistence of thermotolerant Campylobacter in water, especially as a viable but non-cultivable form (VNC), was involved in human campylobacteriosis, the capacities of survival and resuscitation of a significant collection of 85 strains in aqueous microcosms were investigated. Two-thirds of these strains (68%) were not detectable on agar medium after a stay of 14-21 days, whereas 21% reached this state before 14 days and 11% were non-cultivable after a stay of 21 days. Some strains remained cultivable after 35 days in a shaken aqueous microcosm and beyond 60 days without shaking. After 30 days, 51% of the non-detectable strains by conventional culture were recovered after injection in 9-day fertilised chicken eggs. A kinetic study showed that the age of the viable but non-cultivable forms and characteristics of the strains could explain the variations of recovery. These results suggest that viable but non-cultivable forms of Campylobacter could be a potential risk of colonisation of human or animals and that an embryonic factor seems to be essential to allow resuscitation.

RESEARCH: Ecological Information System: Analyzing the Communication and Utilization of Scientific Information in Mexico

/ This study is concerned with the role that communication can play in facilitating the utilization of ecological information by different sectors of society involved in environmental decision-making. The ecological information system is used as a conceptual framework. This system is a model for the analysis of interactions between three sectors involved in the management of natural resources: researchers in ecology, change agents, and rural producers. Two case studies of organizations carrying out scientific research aimed at finding and implementing sustainable strategies of resource management were carried out. The purpose was to examine how real situations function in terms of communication strategies and to analyze such situations in relation to the model proposed. The analysis revealed the importance of promoting the feedback of information from change agents and rural producers to the research sector and the incorporation of this information into the research process. It also emphasized the relevance of having "active utilizer constituencies" within the rural producers who make demands upon the entire system in order to satisfy information needs. The creation of linkage systems facilitating the connection between the generation and utilization of information was supported. In particular, the establishment of special teams within research institutions is proposed, which could promote the links between the sectors through the use of communication as an instrument of work.

Survival of Vibrio cholerae O1 in ceviche and its reduction by heat pretreatment of raw ingredients

The survival of Vibrio cholerae O1 serotypes Inaba and Ogawa was determined in ceviche prepared from inoculated ground fish. Ground mackerel purchased from a seafood distribution center was inoculated with V. cholerae and stored at 8 or 20 degrees C. Counts of V. cholerae decreased in 2.6 to 2.7 log10 CFU/g during 96 h of storage at 8 degrees C or 2.5 to 2.6 log10 CFU/g during 24 h at 20 degrees C. Survival studies indicated that serotype Inaba decreased its number following a linear or retarded trend, whereas serotype Ogawa followed an accelerated death trend. No effect of the initial level of inoculum was observed. Odor scores of ceviche indicated that this food became marginally acceptable within as little as 48 h of storage at 8 degrees C or 3 h at 20 degrees C and were related to total volatile nitrogen values but not to aerobic plate counts, pH, or coliform counts. A heat pretreatment that consisted of stirring 100 g of inoculated ground fish into 40 ml of boiling water produced an 8-log reduction of V. cholerae within 3 min without affecting the color, odor, or flavor of ceviche prepared with such pretreated fish. According to this study, V. cholerae present in contaminated ceviche will likely survive longer than the shelf life of this food. Preheating the ground raw fish used for preparing ceviche for 3 min should effectively eliminate V. cholerae O1, providing science-based conditions for implementing a critical control point if a hazard analysis critical control point plan were to be developed for preparation of ceviche.

[Vascular hemichorea: clinical-radiological correlation]

INTRODUCTION

Hemichorea is uncommon in acute cerebrovascular accidents. Its appearance is in relation to the contralateral involvement of the basal ganglia, particularly the striate ganglion. With current neuroimaging techniques it is possible to identify the lesions responsible for these abnormal movements. Magnetic resonance (MR) is the technique of choice for detection of small sized lesions.

OBJECTIVE

We have analysed our series of patients to try to relate the site of the lesion to the appearance of chorea.

PATIENTS AND METHODS

We made a retrospective study of the cases of hemichorea of vascular origin admitted between January 1993 and April 1999. In all cases, cerebral CAT and/or MR had been done to find the site of the lesion.

RESULTS

A total of 10 patients with an average age of 72.5 years (range: 55-85) was found. In eight of them (80%) lesions were found in the basal ganglia, half of which were of ischemic type and the other half hemorrhagic. The sites were: caudate nucleus in one case (10%), thalamus in two cases (20%) and capsulo-lenticular lesions in five cases (50%). All lesions were contralateral to the side of the body affected except in one case with a left thalamic haematoma and homolateral hemichorea.

CONCLUSIONS

The lesions found were very varied in site. In 20% of the cases they were not detected by conventional neuroimaging techniques. This fact supports the concept of a functional global network of the basal ganglia which may be interrupted at several points and lead to the same clinical findings.

Post-pH effect in oral streptococci

OBJECTIVES

To study the post-pH effect (PpHE) in 11 strains of oral streptococci belonging to Streptococcus sanguis, S. mitis, S. gordonii, S. mutans and S. sobrinus by using the BacT/Alert microbial detection system.

METHODS

The bacterial cultures were exposed to a different pH (3.6, 4.0, 4.6, 5.0, 5.6, 7.0, 7.5, 8.0 and 8.6) for 1 h, and then returned to a neutral medium. The automated BacT/Alert system determined resumed microbial growth by measuring CO2 generation. The PpHE expresses the time difference between resumed growth (after pH shock) and optimal growth (pH 7.0 used as the control).

RESULTS

PpHE was found to be minimal for alkaline pH values, and to be strain and species dependent.

CONCLUSIONS

The PpHE may be useful as an ecological determinant or as an indicator of the cariogenicity of oral streptococci.

Growth of Helicobacter pylori in various liquid and plating media

The objectives of this research were to compare commonly used liquid and plating media to elucidate whether one medium provided superior growth of Helicobacter pylori in vitro. The liquid media compared were Mueller-Hinton broth, brain heart infusion broth and H. pylori special peptone broth, formulated in this laboratory. No significant differences in growth rates were noted and shaking during the incubation of broths was not essential for good growth. The plating media compared included Columbia agar, Mueller-Hinton agar, modified Glupczynski's Brussels campylobacter charcoal agar, Johnson-Murano agar and H. pylori special peptone agar (HPSPA). None of the non-specific plating media that have been used historically to culture H. pylori exhibited any particular advantage. However, HPSPA provided an obvious advantage in colony size. Helicobacter pylori special peptone agar enhances the cultivation of H. pylori and could improve the recovery of the bacterium from clinical samples in vitro.

[A lymphoepithelial cyst of the parotid gland in an advanced stage of HIV infection. A rare association]

Parotid lymphoepithelial cyst is an unusual morbid entity which incidence has been increased lately because of its association to early stages of HIV infection. We report the case of an heterosexual man, 39, ex-addicted to parenteral drugs, HIV positive, stage C3. Its left parotid gland presented with a lump of low rate growth which was with fine needle punctured and aspirate for biopsy and after followed by the mass removal. Cytological and histopathological examination confirmed the diagnosis (lymphoepithelial cyst). The aim for our work is to explain the clinic and pathological features of this condition and emphasize the fact of its possible presentation in positive HIV patients in advanced stages.

Antibacterial activity of glass-ionomer restorative cements exposed to cavity-producing microorganisms

The antibacterial activity of the glass-ionomer restorative cements Ketac-Fil, Ketac-Silver, Fuji II LC, and Vitremer was studied in vitro, in conjunction with a total of 32 strains of five bacterial genera that may be associated with dental caries: Streptococcus spp, Lactobacillus spp, Actinomyces spp, Porphyromonas spp, and Clostridium spp. Agar plate diffusion was the method used for the bacterial cultures, which included a chlorhexidine control. All four glass-ionomer cements were found to inhibit bacterial growth, though with noteworthy differences in their spheres of action. Vitremer was the cement determined to have the greatest antibacterial effects, whereas Ketac-Silver presented the least inhibitory action.

A new double-stranded RNA mycovirus from Botrytis cinerea

A simple double-stranded RNA mycovirus was detected in a wild-type Botrytis cinerea 55k strain. The virus was located in the fungus cytoplasm as free particles of approximately 28 nm in diameter. The mycovirus possesses a single double-stranded genome segment of 1.8 kilobase pairs (kbp) encapsidated within an isometric protein coat whose main structural component is a polypeptide of 68 kDa. Cells infected with this virus showed an important degree of cellular degeneration.

Reduction of Escherichia coli O157:H7 and Salmonella typhimurium on beef carcass surfaces using acidified sodium chlorite

The efficacy of a phosphoric acid-activated acidified sodium chloride (PASC) spray and a citric acid-activated acidified sodium chlorite (CASC) spray applied at room temperature (22.4 to 24.7 degrees C) in combination with a water wash was compared with that of a water wash only treatment for reduction of Escherichia coli O157:H7 and Salmonella Typhimurium inoculated onto various hot-boned individual beef carcass surface regions (inside round, outside round, brisket, flank, and clod). Initial counts of 5.5 and 5.4 log CFU/cm2 were obtained after inoculation with E. coli O157:H7 and Salmonella Typhimurium, respectively. Initial numbers for both pathogens were reduced by 3.8 to 3.9 log cycles by water wash followed by PASC spray and by 4.5 to 4.6 log cycles by water wash followed by CASC spray. The sprays consisted of applying 140 ml of the appropriate sanitizing solution for 10 s at 69 kPa. Corresponding reduction values obtained by water wash alone were 2.3 log. The performance of CASC appeared to be consistently better than that of PASC. In general, no effect of the carcass surface region was observed on the log reductions for either pathogen, except for the inside round, which consistently had lower reductions. Both PASC and CASC were capable of effectively reducing pathogens spread to areas beyond the initial contaminated area of the cuts to levels close to or below the counting method detection limit (0.5 log CFU/cm2). However, 30 to 50% of the carcasses treated by these antimicrobial solutions still yielded countable colonies. Results of this study indicate that acidified sodium chlorite sprays are effective for decontaminating beef carcass surfaces.

Decontamination of beef carcass surface tissue by steam vacuuming alone and combined with hot water and lactic acid sprays

Hot beef carcass surface regions (outside round, brisket, and clod) contaminated with feces spread over a 5-cm2 (1-in2) area were cleaned using a steam-vacuum spot-cleaning system alone or combined with subsequent sanitizing treatments of hot water (95 degrees C at the nozzle), or warm (55 degrees C) 2% lactic acid spray, or combinations of these two sanitizing methods. These treatments were compared for effectiveness in reducing aerobic plate counts (APC) and counts of Enterobacteriaceae, total coliforms, thermotolerant coliforms, and Escherichia coli. All treatments significantly reduced the numbers of each group of bacteria on beef carcass surfaces. However, reductions obtained by steam vacuuming were significantly smaller than those obtained by a combination of steam vacuuming with any sanitizing treatment. No differences in bacterial reductions were observed between different carcass surface regions. Steam vacuuming reduced the number of different indicator organisms tested by ca. 3.0 log cycles but also spread the bacterial contamination to areas of the carcass surface adjacent to the contaminated sites. This relocated contamination after steam vacuuming was most effectively reduced by spraying with hot water and then lactic acid. This combined treatment consistently reduced the numbers of Enterobacteriaceae, total and thermotolerant coliforms, and E. coli to undetectable levels (<1.0 log10 CFU/cm2) on areas outside the initial 5-cm2 inoculated areas.

The PecT repressor coregulates synthesis of exopolysaccharides and virulence factors in Erwinia chrysanthemi

Erwinia chrysanthemi 3937 synthesizes an exopolysaccharide (EPS) composed of rhamnose, galactose, and galacturonic acid. Fourteen transcriptional fusions in genes required for EPS synthesis, named eps, were obtained by Tn5-B21 mutagenesis. Eleven of them are clustered on the chromosome and are repressed by PecT, a regulator of pectate lyase synthesis. In addition, expression of these fusions is repressed by the catabolite regulatory protein, CRP, and induced in low osmolarity medium. The three other mutations are located in genes that are not regulated by pecT. A 13-kb DNA fragment containing pecT-regulated eps genes has been cloned. All the genes identified on this fragment are transcribed in the same orientation and could form a large operon. The promoter region of this operon has been sequenced. It contains a JUMP-start sequence, a sequence required for the expression of polysaccharide-associated operons. E. chrysanthemi 3937 produces a systemic soft rot on its host Saintpaulia ionantha. An eps mutant was less efficient than the wild-type strain in initiating a maceration symptom, suggesting that production of EPS is required for the full expression of the E. chrysanthemi virulence.

[The usefulness of the CLA-1 cell subline for the isolation of the dengue virus]

The live CLA-1 obtained by cloning from the cell live AP-61 (Aedes pseudocutellaris) was used to intend the isolation of dengue virus in 10 serum samples patients in acute phase and clinical diagnosis of dengue. Samples were parallelly inoculated in C6/36 and AP-61 as control systems. Of the 10 samples, 6 were positive in the 3 systems evidencing sensitivity and usefulness for the isolation of the cell subline CLA-1.

The PecT repressor interacts with regulatory regions of pectate lyase genes in Erwinia chrysanthemi

Erwinia chrysanthemi is a broad host range phytopathogenic enterobacterium responsible for soft-rot disease of many plant species. The pecT gene encodes a repressor that negatively regulates the expression of virulence factors, such as pectinases, motility or exopolysaccharide synthesis. The cloned pecT gene was overexpressed using a phage T7 system. The purification of PecT involved the use of a TSK-heparin column and delivered the PecT protein that was purified to near homogeneity. The purified repressor displayed a 34 kDa apparent molecular mass. Gel-filtration experiments revealed that the PecT protein is a dimer. Band-shift assays demonstrated that the tetramer of the PecT protein could specifically bind in vitro to the regulatory regions of the pectate lyase genes with variable affinities. In addition, we demonstrated that PecT represses its own synthesis by interacting independently with two 200 bp regions, R1 and R2, located from -382 to -632 and -17 to -234, respectively, from the distal P1 promoter and from -465 to -715 and -100 to -317 from the P2 proximal promoter. We propose a model that explains the regulation exerted by PecT on its target genes and that integrates the phenotype obtained with a PecT overproducing pec-1 mutant or a pecT mutant.

[The physicochemical characterization of the strains isolated during the outbreak of epidemic neuropathy in Cuba. II]

The presence of 2 agents such as a Cox A9 strain and another mild cytopathogenic effect-producing strain, both isolated from patients presenting with epidemic neuropathy is reported in this paper. A mild cutopathogenic effect which was propagated in successive dilutions was developed in the dilution 10(-4) by means of the neutralization test of a Coxsackie A9 virus with its homologous hyperimmune serum. A gradient in saccharose was performed in a mild cytopathogenic effect-producing strain and a typical cytopathogenic effect of an Enterovirus developed from one of the fractions passed in tissular cultures in the presence phosphonoacetic acid (PAA). The possible pathogenic role of these viruses are discussed.

[The factors affecting the growth of the agent, producing a mild cytopathic effect, isolated in patients with epidemic neuropathy]

Certain factors influencing upon the growth of the agent producer of mild cytopathogenic effect and isolated from the cerebrospinal fluid of patients presenting with epidemic neuropathy are described in this paper. It was demonstrated that a concentration of NaHCO3 was essential for the occurrence of the cytopathogenic effect. Determined concentrations of MnCl2 allowed for the visualization of the cytopathogenic effect and increased viral yields.

[The physicochemical characterization of the agents isolated during the outbreak of epidemic neuropathy in Cuba. I]

This paper reports on the physical and chemical characteristics of agents isolated from serum samples of patients presenting with epidemic neuropathy. The behaviour of isolated enteroviruses was as described for such viruses. Mild cytopathogenic effects-producing agents behaved in a variable form regarding sensitivity to chloroform; on the other hand they were neither sensitive to phosphonoacetic acid (PAA) nor to guanidine hydrochloride (GHC1) and grew in cells previously treated with bromodeoxyuridine (BDUR). These results suggest the presence of agents resembling enteroviruses and enveloped viruses. Further studies for the characterization of such agents need to be performed.

[Standardization of the plaque method for viruses isolated in patients with epidemic neuropathy]

This paper reports on the necessary conditions for plaque development in mild cutopathogenic effect-producing agents which were isolated from samples of the cerebrospinal fluid of patients presenting with epidemic neuropathy.

[Cuban epidemic neuropathy. III. Neutralizing antibodies to the strains isolated and to other enteroviruses in patients and healthy subjects]

Determinations of neutralizing antibodies to the strain 47/93 IPK (CA9) and to the strain 590 were performed in serum samples from patients presenting with epidemic neuropathy and from a group of seemingly healthy subjects. Determinations were also done in the reference strains CA9 and CB1-6 by the microneutralization technique. Patients and their contacts showed significantly higher percentages of neutralizing antibodies to the strain 47/93 than the control group and residents of municipalities with a low rate of the disease. This difference was also confirmed regarding the geometric mean titres with the use of the reference strains CA9 and CB2-4. An increased circulation of the strain 47/93 within the infantile population from 1981 to 1993 was evidenced. Patients exhibited significantly lower percentages and geometric mean titres of neutralizing antibodies to the strain 590 than the control group, despite the fact that in 25/28 certain agents having a mild cytopathogenic effect had been isolated. The possibility of two mechanism of neutralization is stated and an hypothesis on the mechanism by which these viruses may be involved in the pathophysiology of the disease is formulated.

[An immunoenzyme assay for the detection of monoclonal antibodies against the E and NS1 proteins of the dengue virus]

The ELISA was standardized to detect monoclonal antibodies of dengue virus proteins E and NS1. One indirect ELISA was applied, using C6-36 cells inoculated with the A-15 strain, isolated during the dengue 2 epidemic in 1981 as an antigen source. These cells were fixed in ELISA plates at a 200,000 cell/well concentration. A cell control in similar conditions was used. Specific monoclonal antibodies to both proteins were used to standardize the system. Studies at different incubation periods, to determine the highest expression moment of these proteins in the cell membrane, were carried out. The results show a full response at 72 hours postinoculation for both proteins; a 14.7 ng/mL sensitivity was obtained for the detection of NS1, and of 1.43 ng/mL for E protein. This system allows the monoclonal antibodies primary screening to dengue 2 virus E and NS1 proteins.

[Detection of immunoglobulin A in serum and saliva of patients with hepatitis A]

Specific secretory serum IgA antibodies to the hepatitis A virus from samples from patients with clinical symptoms compatible to hepatitis A, their contacts, and healthy subjects were analyzed using an ELISA technique; results were compared with those of specific serum IgM antibodies to the hepatitis A virus. The following results were attained in 175 blood samples: coincidence by 98.8%; sensitivity by 96.8%; and specificity by 100%. Two cases were negative to IGA and positive to IGM. On comparing the presence of IGA in saliva with the presence of IGM in blood, coincidence was of 88.1%; sensitivity, of 40.9% and specificity, of 100%. Of the 22 cases with positive IGM in blood, only 9 showed specific IGA antibodies in the saliva. The 111 cases who had negative IGM in blood were also negative to IGA. The obtained data suggest that specific serum IGA antibodies to the hepatitis A virus are an indicator of a recent or occurrent infection due to this virus and thus it may be considered and alternative for the diagnosis of this disease.

[Enterovirus meningoencephalitis in the last 5 years]

The results of the study of Enterovirus as viral meningoencephalitis producing agents, carried out from 1990 to 1994, are described, 546 feces samples, 95 cerebrospinal fluids and 1,058 matched sera were studied and obtained from 1,388 patients clinically diagnosed with this disease. Samples for viral isolation were inoculated into two different cellular systems. The highest number of isolation was found in diploid cells from human fibroblast. Antibody determinations were carried out by a neutralization test (micromethod) with 11 Enterovirus antigens (Echo 4, 6, 9, 11 and 30; and Coxsackie B1, 2, 3, 4, 5 and 6) and in epidemic periods with the isolated virus. During the years under study, 2 epidemic outbreaks took place: on caused by Coxsackie A9 (1990-1991) and the other one by Echo 30 (1994). A greater positivity to Echo 6 and 11 was found among the matched sera.

Effect of bryostatin 1 on taxol-induced apoptosis and cytotoxicity in human leukemia cells (U937)

We have examined the effects of the macrocyclic lactone protein kinase C (PKC) activator bryostatin 1 on taxol-induced apoptosis and inhibition of clonogenicity in the human monocytic leukemia cell line U937. Exposure of cells to bryostatin 1 (10 nM; 15 hr) after (but not before) a 6-hr incubation with 0.5 microM taxol significantly increased apoptosis and resulted in an approximately 3 log reduction in clonogenicity. Cell cycle analysis revealed that the increase in apoptotic cells following bryostatin 1 treatment occurred primarily in the population undergoing taxol-mediated G2M arrest. The actions of bryostatin 1 were not attributable to potentiation of taxol-induced tubulin stabilization or to a reduction in the intracellular retention of taxol. Following exposure of cells to taxol, the Bcl-2 protein displayed an alteration in mobility that was not modified appreciably by bryostatin 1 treatment. The mobility shift in Bcl-2 protein from cells exposed to taxol followed by bryostatin 1 was eliminated by treatment of lysates with the protein phosphatase 2A (PP2A); the latter effect was blocked by okadaic acid. Treatment of cells with taxol followed by bryostatin 1 did not increase the amount of total Bax (compared with treatment with taxol alone), but did increase the amount of free Bax in the supernatant fraction. Finally, the ability of bryostatin 1 to potentiate taxol-induced apoptosis in U937 cells was mimicked closely by 2'-amino-3'-methoxyflavone (PD98059), a specific inhibitor of the mitogen-activated protein kinase (MAPK) kinase (MEK). Collectively, these findings indicate that bryostatin 1 increases the susceptibility of U937 cells to taxol-induced apoptosis and inhibition of clonogenicity. They also raise the possibility that this phenomenon may involve functional alterations in Bcl-2 and/or other proteins involved in regulation of the cell death pathway.

[Observations on oviposition, hatching and the life span of Triatoma matogrossensis Leite & Barbosa, 1953 (Hemiptera, Reduviidae) as a function of their feeding on pigeons and rabbits]

A laboratory study was carried out concerning the influence of two kinds of blood-meal on egg laying, egg hatching and life span of Triatoma matogrossensis. 68 couples in 4 different groups with 20, 12, 20 and 16 individuals of each sex per group were formed. Maintained under laboratory conditions groups A1 and A2 were fed on pigeons and groups C1 and C2 were fed on rabbits. In relation to egg laying the best results were found in group A1. No differences on egg hatching were found between the groups fed on rabbits and those fed on pigeons. Concerning the life span, no differences between males and females in the 4 groups were observed but group A1 presented the longest life span and group C2 the shortest.

Immunologic and clinical evaluation of postsurgical necrotizing sclerocorneal ulceration

PURPOSE

To perform a clinical, laboratory and pathologic evaluation in patients who had developed a postsurgical necrotizing sclerocorneal ulceration to detect a serious associated autoimmune disorder and to treat the ocular disease early.

METHODS

Nine patients with postsurgical necrotizing sclerocorneal ulceration after uneventful cataract extraction were studied by means of immunohistochemical techniques on conjunctival resections, immunologic serologic studies, and rheumatologic evaluation. Nine healthy subjects who underwent uneventful cataract surgery were used as controls.

RESULTS

The pathologic studies showed a local immunoglobulin M (IgM) and IgG deposition, increased human leukocyte antigen (HLA-DR) expression, and a significant T-helper cell participation in conjunctival biopsies in the most severe ulcerations, which were detected in four patients with underlying autoimmune systemic disorder (rheumatoid arthritis, 45%) and only a macrophagic infiltration in the mildest ulcers in patients (55%) without immune disorders. Serologic features included high titers of rheumatoid factor in the four (45%) patients with rheumatoid arthritis, nonspecific serologic immune alteration in three (33%) patients, and were unremarkable in two (22%) patients. The medical and immunologic evaluations were negative in the control cases. Topically administered cyclosporin A healed the ocular disease.

CONCLUSION

A surgically induced local autoimmune reaction could occur in the incision area in patients with systemic vasculitic disease. There was no underlying systemic disorder in the mildest ulcers, and these ulcers could be due to a defect in the surgical technique. Our results suggest the need for a detailed systemic evaluation in patients with severe postsurgical necrotizing ulceration. Early diagnosis and aggressive medical treatment of the ocular disorder improves the visual outcome.

Comparison of water wash, trimming, and combined hot water and lactic acid treatments for reducing bacteria of fecal origin on beef carcasses

Cleaning treatments, such as high-pressure water wash at 35 degrees C or trim, alone and combined with sanitizing treatments, such as hot water (95 degrees C at the source), warm (55 degrees C) 2% lactic acid spray, and combinations of these two sanitizing methods, were compared for their effectiveness in reducing inoculated numbers (5.0 to 6.0 log CFU/cm2) of Salmonella typhimurium, Escherichia coli O157:H7, aerobic plate counts, Enterobacteriaceae, total coliforms, thermotolerant coliforms, and generic E. coli on hot beef carcass surface areas in a model carcass spray cabinet. Log reductions in numbers of all tested organisms by water wash or trim alone were significantly smaller than the log reductions obtained by the different combined treatments. Regardless of the cleaning treatment (water wash or trim) or surface area, the range for mean log reductions by hot water was from 4.0 to > 4.8 log CFU/cm2, by lactic acid spray was from 4.6 to > 4.9 log CFU/cm2, by hot water followed by lactic acid spray was from 4.5 to > 4.9 log CFU/cm2, and by lactic acid spray followed by hot water was from 4.4 to > 4.6 log CFU/cm2, for S. typhimurium and E. coli O157:H7. Identical reductions were obtained for thermotolerant coliforms and generic E. coli. No differences in bacterial reductions were observed for different carcass surface regions. Water wash and trim treatments caused spreading of the contamination to other areas of the carcass surface while providing an overall reduction in fecal or pathogenic contamination on carcass surface areas. This relocated contamination after either water wash or trim was most effectively reduced by following with hot water and then lactic acid spray. This combined treatment yielded 0% positive samples for S. typhimurium, E. coli O157:H7, thermotolerant coliforms, and generic E. coli on areas outside the inoculated areas, whereas percent positive samples after applying other combined treatments ranged from 22 to 44% for S. typhimurium, 0 to 44% for E. coli O157:H7, and 11 to 33% for both thermotolerant coliforms and generic E. coli. From data collected in this study, it is possible to choose an effective, inexpensive treatment to reduce bacterial contamination on beef carcasses. In addition, the similar reduction rates of total coliforms, thermotolerant coliforms, or generic E. coli may be useful in identifying an indicator to verify the effectiveness of the selected treatment as a critical control point in a Hazard Analysis and Critical Control Point program.

Endothelial damage with cataract surgery techniques

PURPOSE

To evaluate intraoperative endothelial damage after planned extracapsular cataract extraction (ECCE) with difference capsulotomy techniques and phacoemulsification.

SETTING

San Carlos University Hospital, Castroviejo Institute, Madrid, Spain.

METHODS

In this prospective, randomized study, 60 patients with senile cataract scheduled for cataract surgery were divided into three groups of 20 each: Group 1 had phacoemulsification; Group 2, planned ECCE with continuous curvilinear capsulorhexis; and Group 3, ECCE with letter-box capsulotomy. Preoperatively and 3 months postoperatively, endothelial cell density, percentage of hexagonality, and the cell size variation coefficient were determined by contact specular microscopy; endothelial permeability was examined by anterior segment fluorophotometry and central corneal thickness, by ultrasonic pachymetry. Results were analyzed using the two-tailed Student's t-test and analysis of variance.

RESULTS

In all three groups, endothelial permeability and cell loss increased significantly from the preoperative values, but there were not significant differences among the postoperative values. Mean cell loss was 11.8% in Group 1, 12.8% in Group 2, and 10.1% in Group 3. There were no differences between the preoperative and postoperative morphometric indexes. Postoperative pachymetric measurements were not significant.

CONCLUSIONS

Endothelial response was not statistically significantly different among the surgical techniques, although endothelial damage was lower in Group 3, which could indicate a protective effect of the anterior capsule during cataract extraction. Endothelial barrier function remained disturbed despite the apparent morphological stabilization.

Chemical dehairing of bovine skin to reduce pathogenic bacteria and bacteria of fecal origin

A chemical dehairing process was applied to artificially contaminated bovine hide to evaluate the effect on populations of Escherichia coli O157:H7 and Salmonella Typhimurium, as well as other strains of E. coli, total coliforms, and aerobic plate counts (APC). Pieces of hide (4 cm2) were contaminated with bovine feces inoculated with both rifampicin-resistant E. coli O157:H7 and S. Typhimurium to yield a final count of each pathogen of ca. 5.0 log10 CFU/cm2, or with noninoculated feces which produced an approximate final APC of 6.0 log10 CFU/cm2 and a coliform and E. coli count of 5.0 log10 CFU/cm2. Counts of pathogens, APC, coliforms, and E. coli were conducted before and after applying the dehairing treatment. S. Typhimurium and E. coil O157:H7 populations were significantly reduced from initial numbers (5.1 to 5.3 log10 CFU/cm2) to levels below the detection limit of 0.5 log10 CFU/cm2 after chemical dehairing. APC, coliforms, and E. coli counts were also reduced significantly after dehairing, with reductions of 3.4 for APC, 3.9 for coliforms, and > 4.3 log10 CFU/cm2 for other E. coli strains. Since the hide is a major source of fecal contamination of beef carcass surfaces, chemical dehairing may be beneficial in reducing overall contamination of carcasses.

Use of hot water for beef carcass decontamination

Hot water treatment of beef carcass surfaces for reduction of Escherichia coli O157:H7, Salmonella typhimurium, and various indicator organisms was studied using a model carcass spray cabinet. Paired hot carcass surface regions with different external fat characteristics (inside round, outside round, brisket, flank, and clod) were removed from carcasses immediately after the slaughter and dressing process. All cuts were inoculated with bovine feces containing 10(6)/g each of rifampicin-resistant E. coli O157:H7 and S. typhimurium, or with uninoculated bovine feces. Surfaces then were exposed to a carcass water wash or a water wash followed by hot water spray (95 degrees C). Counts of rifampicin-resistant Salmonella and E. coli or aerobic plate count (APC) and coliform counts were conducted before and after each treatment. All treatments significantly reduced levels of pathogens from the initial inoculation level of 5.0 log(10) CFU/cm2. Treatments including hot water sprays provided mean reductions of initial counts for E. coli O157:H7 and S. typhimurium of 3.7 and 3.8 log, APC reductions of 2.9 log, and coliform and thermotolerant coliform count reductions of 3.3 log. The efficacy of hot water treatments was affected by the carcass surface region, but not by delaying the treatment (30 min) after contaminating the surface. Verification of efficacy of hot water interventions used as critical control points in a hazard analysis critical control point (HACCP) system may be possible using coliform counts.

Peripheral Melt of Flap after Laser in situ Keratomileusis

BACKGROUND

Laser in situ keratomileusis (LASIK) is an effective procedure to correct myopia. It may have complications related to the flap, such as epithelial ingrowth and stromal melt.

METHODS

We report on a patient who developed extensive epithelial ingrowth and partial keratolysis of the flap following LASIK. This complication was treated by lifting the flap and removing the epithelium from within the interface.

RESULTS

Progressive keratolysis (stromal melt) can result in irregular astigmatism and loss of vision as well as photophobia and ciliary injection. The pathogenesis is not completely understood although the epithelial ingrowth in the interface is always present, and epithelial-stromal interaction with production of proteases may be involved.

CONCLUSION

Epithelial ingrowth may develop in the lamellar interface after LASIK and be associated with melting of the edge of the flap. This undesirable complication can be successfully managed with early surgical removal of the epithelium and proper attachment of the flap.

A double-stranded RNA mycovirus in Botrytis cinerea

In wild-type Botrytis cinerea CVg25 strain we have detected the presence of extrachromosomal genetic elements corresponding to double-stranded RNA molecules. These genetic elements have been designated L, M1 and M2 with molecular sizes of 8.3, 2.0 and 1.4 kb, respectively. The visualization by electron microscopy of mycelium ultrathin sections from B. cinerea CVg25 showed the presence of isometric virus-like particles of about 40 nm in diameter. Linear sucrose gradient centrifugation of mycelium-free extracts was done to determine if the double-stranded RNAs were associated with virus-like particles. The gradient profile obtained at 260 and 280 nm revealed a major peak that was analyzed by both agarose-gel electrophoresis and electron microscopy. It was observed that only the L-double-stranded RNA molecule copurified with isometric virus-like particles. These virus-like particles had a similar morphology and size as those detected by electron microscopy in the mycelium sections. These results suggest that only the L-double-stranded RNA would be encapsidated.

In-vitro susceptibility, tolerance and glycocalyx production in Streptococcus mutans

We studied the presence of high-level resistance to aminoglycosides, penicillin tolerance and glycocalyx production in 160 isolates of Streptococcus mutans. Susceptibility to amoxycillin, cefazolin, imipenem, erythromycin, clindamycin, vancomycin and teicoplanin was also investigated. Of the isolates analysed, 58.8% produced glycocalyx in vitro and 2.5% were penicillin-tolerant. High-level resistance to streptomycin was found in 16.3% of the isolates, but all were sensitive to all other antibiotics tested. We found no significant relationship between glycocalyx production and high-level streptomycin resistance, penicillin tolerance or antibiotic susceptibility, except for a greater susceptibility to clindamycin and vancomycin in isolates that produced glycocalyx. Although our findings reflect the clinically favourable pattern of susceptibility currently found in this species, the appearance in some isolates of resistance, tolerance and glycocalyx production should be investigated because of the risks involved in endocarditis caused by S. mutans.