Intra-amoebic localization of Arcobacter butzleri as an endocytobiont of Acanthamoeba castellanii

Acanthamoeba castellanii is a free-living amoeba found mainly in humid environments and Arcobacter butzleri is an emerging zoonotic pathogen, both can establish in vitro endosymbiotic relationships in the absence of bacterial replication. We analyzed the localization of A. butzleri within A. castellanii establishing their association with endoplasmic reticulum vesicles and mitochondria. Through confocal microscopy, we observed that during the early stages of endosymbiosis, there is not colocalization between amoebic vacuoles containing A. butzleri and mitochondria or ER vesicles of A. castellanii. Considering that energy production of this bacterium occurs via metabolism of amino acids or the tricarboxylic acid cycle, these results contribute to explain the absence of bacterial replication, since A. butzleri would not have access to the nutrients found in endoplasmic reticulum vesicles and mitochondria. In addition, we observe that A. butzleri induces significantly the actin polymerization of A. castellanii during the early stages of endosymbiosis.

Comparison of media and growth conditions for culturing enterohepatic Helicobacter species

This research aims to compare the culturing conditions for enterohepatic Helicobacter, evaluating culture media, incubation atmosphere and susceptibility to antimicrobials used to generate selective conditions. Four common media for the closely related genus Campylobacter (Columbia, Bolton, Brucella and CCDA agar), as well as the need for hydrogen in the microaerobic incubation atmosphere, were evaluated. Serial dilutions of 13 strains belonging to six species (H. apodemus, H. bilis, H. canicola, H. canis, H. equorum and Helicobacter sp.) were inoculated in each media and incubated at 37°C for 48 to 96 h using CampyGen (OXOID) and gaseous exchange (including hydrogen) in parallel. Columbia or Brucella agars were the most appropriate for culturing EHH (P < 0·05). However, there was no significant difference between the atmospheres evaluated (P = 0·13). In addition, minimal inhibitory concentration for six antibiotics showed that all isolates were resistant to trimethoprim, whereas for the rest of the antibiotics (cephalothin, cefoperazone, cefsulodin, teicoplanin and vancomycin) the inhibition range was between 8 and 64 μg ml^{- 1} . Our findings suggest that Columbia or Brucella media, regardless of the use of hydrogen, can be used for the EHH isolation. In addition, the concentration of antibiotics included in commercial campylobacteria supplements is suitable for EHH species recovery. SIGNIFICANCE AND IMPACT OF THE STUDY: Enterohepatic Helicobacter (EHH) infections have been associated with several diseases in humans such as acute gastroenteritis, inflammatory bowel disease and hepatobiliary diseases. Although they are frequently detected in clinical samples by molecular methods, only occasionally they are isolated using culture conditions described for the taxonomic related pathogen Campylobacter sp. This is because the optimal conditions for the isolation of EHH have not yet been described, which results in an underestimation of the prevalence and clinical importance of these emerging pathogens. Therefore, this study provides insight for culturing EHH species.

Development of a third-generation biosensor to determine sterigmatocystin mycotoxin: An early warning system to detect aflatoxin B1

A third-generation enzymatic biosensor was developed to quantify sterigmatocystin (STEH). It was based on a glassy carbon electrode modified with a composite of the soybean peroxidase enzyme (SPE) and chemically reduced graphene oxide. The optimal conditions to construct the biosensor were obtained through an experimental design based on the response surfaces methodology. The experiments were performed in 0.1 mol L-1 phosphate buffer solution, pH 5. Amperometric measurements were carried out at - 0.09 V vs Ag/AgCl (3 mol L-1 NaCl). The biosensor showed a lineal response in the concentration range from 6.9 × 10-9 to 5.0 × 10-7 mol L-1. The limit of detection was 2.3 × 10-9 mol L-1 for a signal: noise ratio of 3: 1. Values of the apparent Michaellis-Menten constant, KMapp, obtained by using both Lineweaver-Burk and Eadi-Hofstee methods were (1.5 ± 0.2) × 10-6 and (1.2 ± 0.2) × 10-6 mol L-1, respectively. STEH was analyzed in corn samples spiked with STEH, with an average recovery of 96.5%. The biosensor was also used to determine STEH in corn samples inoculated with the Aspergillus flavus fungus, which is an aflatoxins producer. Considering that STEH is a precursor of aflatoxin B1 (AFB1) in its biological transformation, its decrease over time was related to the production of AFB1. The STEH concentration determined using the biosensor was in very good agreement with that determined by HPLC.

Identification and genetic characterization of a gibberellin 2-oxidase gene that controls tree stature and reproductive growth in plum

Several dwarf plum genotypes (Prunus salicina L.), due to deficiency of unknown gibberellin (GA) signalling, were identified. A cDNA encoding GA 2-oxidase (PslGA2ox), the major gibberellin catabolic enzyme in plants, was cloned and used to screen the GA-deficient hybrids. This resulted in the identification of a dwarf plum hybrid, designated as DGO24, that exhibits a markedly elevated PslGA2ox signal. Grafting 'Early Golden' (EG), a commercial plum cultivar, on DGO24 (EG/D) enhanced PslGA2ox accumulation in the scion part and generated trees of compact stature. Assessment of active GAs in such trees revealed that DGO24 and EG/D accumulated relatively much lower quantities of main bioactive GAs (GA(1) and GA(4)) than control trees (EG/M). Moreover, the physiological function of PslGA2ox was studied by determining the molecular and developmental consequences due to ectopic expression in Arabidopsis. Among several lines, two groups of homozygous transgenics that exhibited contrasting phenotypes were identified. Group-1 displayed a dwarf growth pattern typical of mutants with a GA deficiency including smaller leaves, shorter stems, and delay in the development of reproductive events. In contrast, Group-2 exhibited a 'GA overdose' phenotype as all the plants showed elongated growth, a typical response to GA application, even under limited GA conditions, potentially due to co-suppression of closely related Arabidopsis homologous. The studies reveal the possibility of utilizing PslGA2ox as a marker for developing size-controlling rootstocks in Prunus.

Equine sperm nuclei with different ploidy levels: relationship between the nuclear DNA content and the nuclear area

The aims of this study were to estimate the ability of the Feulgen reaction to identify equine sperm nuclei with different ploidy levels, to determine the frequency of haploid, diploid and polyploid sperm nuclei in the semen of fertile equines and to evaluate the relationship between the nuclear DNA content and the nuclear area. Determination of the ploidy level of Feulgen-stained spermatozoa using a scanning microspectrophotometer was very similar to the subjective estimations made with a light microscope. This indicates that the Feulgen reaction is a simple, inexpensive and reliable technique to recognise the ploidy level of equine spermatozoa. The incidence of diploid and polyploid spermatozoa, determined with a light microscope in 11 fertile equines, was 0.17 ± 0.08% and 0.027 ± 0.027% respectively. DNA content values obtained by microspectrophotometry in the only equine that presented polyploid spermatozoa allowed us to discriminate between haploid, diploid and polyploid subpopulations. Measurement of the nuclear area discriminated only two subpopulations: one including the haploid and diploid subpopulations and the other including the polyploid one. The similarity between the area of the haploid and diploid sperm nuclei suggests that the increase in DNA content is anisotropic, with a privileged direction of growth perpendicular to the nuclear flattening plane.

Occurrence of plant growth regulators in Psilotum nudum

The endogenous content of the auxin indole-3-acetic acid (IAA), the cytokinins trans-zeatin (tZ), trans-zeatin riboside (tZR), dihydrozeatin (DHZ), dihydrozeatin riboside (DHZR), isopentenyladenine (iP) and isopentenyladenosine (iPR), the gibberellins GA(1), GA(3), GA(4), GA(7), GA(9) and GA(20) in the rhizome and aerial shoots during and after sporogenesis were measured by high-performance liquid chromatography-tandem mass spectrometry in the fern Psilotum nudum. The present study shows, for the first time, the presence of the auxin IAA, the cytokinins tZR, DHZR and iP, and the gibberellins GA(4), GA(9) and GA(20) in the rhizome and aerial shoots of this species and suggests a possible role of gibberellins in the evolution of ferns.

Schizophrenia treatment. Critical review on the drugs and mechanisms of action of antipsychotics

Schizophrenic treatment was developed during the second half of the last century, mainly within the context of the development of antipsychotic drugs. Even though there has been significant progress due to the availability and use of multiple drugs, these can still be classified into three basic groups of antipsychotic drugs (atypical antipsychotics, typical antipsychotics and dopamine partial agonist antipsychotics). Their primary antipsychotic mechanism is still the action on the dopamine systems. Many of the second-generation antipsychotics are believed to offer advantages over first-generation agents in the treatment for schizophrenia. However, the drug properties that provide the different therapeutic effects from those of the first generation are not clear and some adverse effects may still affect the patient's health and quality of life. Furthermore, the efficacy of the antipsychotics is limited. This has led to the use of adjuvant medications to strengthen the treatment effects. On the other hand, work is being done on the development of new research lines to develop new non-dopaminergic antipsychotic drugs, with not very successful results. The aim of this paper is to make a brief review on the current therapeutic armamentarium for schizophrenia, the strategies to develop drugs, and theories of mechanisms of action of antipsychotics. Emphasis is placed on the new therapeutic targets for the development of future treatments.

Gibberellins and antheridiogen on sex in Blechnum spicant L

The role of gibberellins (GAs) in determining sex in the gametophyte of the fern Blechnum spicant L. was studied through (a) the effect of exogenous GA(4+7) and GA3 (b) quantitation of the endogenous levels of GA1, GA3, GA4, GA7, GA9, and GA20 in male and female gametophytes, and (c) the effect of flurprimidol, a GAs biosynthesis inhibitor of the steps of oxidation of ent-kaureno to ent-kaurenoic acid. Our results show that GA(4+7) had a slight effect of inducing either male or female sexual organs, antheridia and archegonia, respectively. The endogenous GAs content was not significantly different between sexes, but the GA4, GA7, and GA20 levels were raised above those of the other GAs in both sexes. Neither antheridiogen biosynthesis nor antheridia formation was inhibited by flurprimidol. Gametophytes regenerated from homogenized mature gametophytes (HG) show a different physiological behavior than spore-derived gametophytes. In the first case, gametophytes are males and synthesize antheridiogen before they attain maturity, in contrast to what occurs in spore-derived gametophytes which are females and synthesize antheridiogen when mature.

Exogenous and endogenous growth regulators on apogamy in Dryopteris affinis (Lowe) Fraser-Jenkins sp. affinis

This work showed for the first time the relationship between the effect of exogenous auxins and gibberellins on apogamy in Dryopteris affinis (Lowe) Fraser-Jenkins sp. affinis and its endogenous contents during early apogamic events. The addition of NAA (0.53 and 5.37 microM) or GA(3) 2.8 microM to an MS solid medium significantly increased apogamous sporophyte formation. BA induced brown callus that regenerated sporophytes in a hormone-free medium. The endogenous contents of GA(1), GA(3), GA(4), GA(7), GA(9) and IAA were determined by GC-MS in gametophytes cultured on MS solid medium, before and during early stages of apogamous embryo development. The accumulation of both GA(9) and IAA before embryo development was evident as high levels of GA(4) in the earliest analysed stage of embryo development and high levels of GA(3) in elongating shoots were found. The role of gibberellins on apogamy was also supported by data showing a decrease in the percentage of gametophytes developing embryos because of the addition of flurprimidol to the culture medium.

Capillary electrophoresis determination of loratadine and related impurities

While HPLC has traditionally been the method of choice for purity determination of pharmaceutical substances, capillary electrophoresis (CE) offers a different selectivity and hence it is a complementary technique to HPLC. Loratadine, an antihistamine, could include in its raw material seven impurities that ought to be separated, identified and quantified for drug development and quality control. As a complementary tool for undoubtful identification, a CE method has been developed. The separation was carried out with an uncoated fused-silica capillary (57 cm x 50 microm ID) and was operated at 20 kV potential. Temperature was maintained at 25 degrees C. The final separation buffer was prepared with 100 mM H(3)PO(4) made up to pH 2.5 with NaOH and with 10% acetonitrile added (v/v). Impurities can be detected at the 0.1% level of the active and validation parameters for linearity accuracy and precision are adequate for all the analytes and that permits to consider the method reliable and suitable for application to long-term stability and purity studies.

LC determination of loratadine and related impurities

Loratadine, an antihistamine, could include in its raw material seven impurities that ought to be separated identified and quantified for drug development and quality control. A HPLC method employing a SymmetryShield RP8 column has been developed and validated for loratadine and related compounds measurement, the last ones under the 0.1% level. The mobile phase consisted of methanol-buffer A (65:35, v/v), being buffer A: H(3)PO(4) 10 mM (H(2)O) brought up to pH 7.00 with triethylamine. UV detection was performed at 244 nm. Validation parameters for linearity, accuracy and precision are in agreement with ICH guidelines for all the analytes and that permits to consider the method reliable and suitable for application to long-term stability and purity studies.

Antibodies anti-Chlamydia pneumoniae and anti-Mycoplasma pneumoniae in patients with negative serology for hantavirus. Retrospective study

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or = 1:16 for C. pneumoniae and M. pneumoniae were found in 8.6% and 17.1% of the serum, respectively, showing evidence of recent or current infection.

[Tuberculosis in the V Sanitary Zone of Buenos Aires Province. Analysis of its trends between 1984 and 1996]

Tuberculosis (TB) continues to be a serious health problem in most of the districts in the 5th Sanitary Region of Buenos Aires Province (RSV) which is located in North Buenos Aires City suburbs. The aim of this study was to analyse and compare the evolution of the TB epidemiological situation in ten districts, in a thirteen year period (1984-96) and to analyse possible reasons for differences. The average annual variation (VAP) of morbidity rate was calculated in order to estimate the trends of TB in these communities along time. Reporting to the National and Provincial TB Control Programmes of TB cases is mandatory for physicians and these data were used as a source of information for the number of cases and rates. A statistical analysis was performed. Our results showed that the VAP value for the whole RSV was lower than -5.0%. On this basis several districts were identified as having a TB critical situation. The proportion of smear positive cases among TB patients reported decreased during this period, suggesting that smear microscopy was being poorly used as a diagnostic tool for TB. Furthermore, the cure rates of the patients attained--in average--only 60.0% and several warning indicators (IA)--like TB meningitis cases and mortality due to TB in people younger than thirty years old, as well as TB--HIV/AIDS association--have been observed to grow in several districts. Previous world global experience and those obtained in other provinces in our own country, suggest that the unique possible strategy for modifying this situation, is to set up the directly observed treatment (DOTS), according to World Health Organization/International Union Against Tuberculosis and Lung Diseases (WHO IVATLD) recommendations, in order to achieve the control of TB.

Expression of invasiveness of Campylobacter jejuni ssp. jejuni after serial intraperitoneal passages in mice

We investigated the possibility of inducing the expression of invasiveness in 10 non-invading, laboratory-adapted Campylobacter jejuni ssp. jejuni strains, after serial intraperitoneal (i.p.) passage in mice. All the strains expressed invasive capacity after the first passage, with an increase in invasion rates and the number of internalized bacteria after each passage. These results suggest that i.p. passage enhances the expression of invasiveness in C. jejuni ssp. jejuni strains.

Antimicrobial susceptibility of Campylobacter jejuni subsp. jejuni assessed by E-test and double dilution agar method in Southern Chile

The susceptibility patterns of 108 Campylobacter jejuni subsp. jejuni clinical strains, to six antimicrobial agents was determined by using the E-test and the double dilution agar methods. Using both methods, no strain was found to be resistant to ciprofloxacin, erythromycin and gentamicin, but two (1.8%) were resistant to tetracycline and all to aztreonam. Seven (6.5%) strains were resistant to ampicillin by the E-test and five (4.6%) by the double dilution agar method and by both methods. No great discrepancies were observed between both methods.

Heart transplantation: influence of the surgical technique on sinus function

This study analyzes the influence of the surgical technique on the development of sinus dysfunction. Cycle length, corrected sinus node recovery time, and sinoatrial conduction time were determined in 4 groups of dogs under the following conditions: group 1, controls; group 2, subjected to heterotopic heart transplantation with conservation of atrial anatomy; group 3, subjected to orthotopic heart transplantation by using a standard technique; and group 4, treated as in group 3, but with an ischemic time of 24 hours. The cycle length was prolonged in all the treated groups when compared with the controls (P < .01), an effect attributed to the disconnection of the autonomic nervous system during the transplantation procedure. The corrected sinus node recovery time and sinoatrial conduction time were significantly longer in all the animals in groups 3 and 4 when compared with those of groups 1 and 2 (P < .01); however, there were no significant differences between groups 3 and 4 or between groups 1 and 2. These results suggest that the atrial anatomy play a more relevant role than the ischemic time in the origin of sinus dysfunction occurring after orthotopic heart transplantation.

[The relationship of Campylobacter jejuni subsp. jejuni enterotoxigenicity and the increase of cAMP and electrolyte changes in the rat intestine]

BACKGROUND

Small intestine alterations produced by the enterotoxigenic capacity of Campylobacter jejuni subsp. jejuni are similar to the hydric, electrolytic and pathological changes caused by choleraic and thermolabile Escherichia coli toxins.

AIM

To study the enterotoxigenic capacity of 4 strains of Campylobacter jejuni subsp. jejuni using the intestinal loop model.

MATERIAL AND METHODS

Rat intestinal loops were inoculated with culture filtrates of the four strains. Enterotoxigenicity was assessed by fluid accumulation, the increase in Na+ and Cl- in the loop fluid, and cAMP increase in loop tissues. An enterotoxigenic Escherichia coil strain and sterile Brucella both were used as positive and negative controls, respectively.

RESULTS

The filtrates of two strains produced fluid accumulation in the loops, significantly increased Na+ and Cl- secretion to the intestinal lumen and increased tissue cAMP levels.

CONCLUSIONS

Some strains of Campylobacter jejuni subsp. jejuni are able to show enterotoxigenicity in vivo, increasing cAMP levels in the intestinal cells and altering electrolyte exchange mechanisms.

[Primary ureteral amyloidosis]

OBJECTIVE

Two additional cases of primary ureteral amyloidosis are described. The current literature and clinical classification of the disease are reviewed.

METHODS

Over a period of 18 months, we observed two cases of organic ureteral stenosis whose etiology was difficult to determine. The first case warranted a nephroureterectomy due to the condition of the compromised urinary tract. Analysis of the surgical specimen showed histological evidence of ureteral amyloidosis. In the second case, the previous experience allowed a preoperative diagnosis to be made, an exceptional situation that permitted conservative surgery. Characterization of the amyloid proteins was done in both cases with immunochemical study by Western Blot.

RESULTS

Two patients with primary ureteral amyloidosis were surgically treated. The first case underwent complete excision of the urinary tract. The second case, who had a single kidney, was treated by conservative surgery. In both cases we identified a fragment of the lambda light chain of immunoglobulin by Western Blot characterization as previously reported in localized amyloidosis.

CONCLUSIONS

Although ureteral amyloidosis is an infrequent disease, it should be seriously considered in the differential diagnosis of organic ureteral stenosis in order to avoid unnecessary excision. To our knowledge, these are the first cases of ureteral amyloidosis with immunochemical characterization of the amyloid protein.

Cape Town solution in prolonged myocardial preservation: structural and ultrastructural study

This study deals with myocardial preservation after 24 hours of continuous, hypothermic and oxygenated perfusion with Cape Town (CT) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. After preservation, aside from mild or moderate mitochondrial changes, the most relevant lesions included edema and vasoconstriction. Reperfusion was followed by the development of areas of necrosis forming contraction bands and an increment in the mitochondrial damage; the intercalated disks conserved their normal structure; edema became more prominent and was invariably accompanied by hemorrhage; vasoconstriction was very pronounced and was accompanied on occasion by evidence of capillary rupture; and inflammatory cells were observed in the interstitium. These results indicate that colloid must be added to Cape Town solution and that reperfusion probably requires selective approaches to deal with vasoconstriction and inflammation.

Arterial blood gases and acid-base balance in geriatric dogs

To compare arterial blood gas pressures and acid-base balance in geriatric and young adult dogs, 23 clinically healthy aged dogs (> 10 years old) and 16 young adult dogs (two to four years old) were studied. Blood gases (PaO2 and PaCO2), pH, Na, K, Ca and Cl were measured in arterial blood samples using selective electrodes. Haemoglobin was quantified with a co-oximeter. Total proteins and phosphorus were measured by spectrophotometry in plasma. The alveolar to arterial PO2 gradient (P(A-a)O2), bicarbonate, anion gap and the base excess of blood were calculated. Quantitative analysis of acid-base balance was carried out by calculating unidentified anions. Old dogs had significantly higher P(A-a)O2 than young dogs (2.5 +/- 0.3 versus 1.4 +/- 0.3 KPa). Although the differences were not significant, aged dogs also had a lower PaO2. No differences were detected in PaCO2, pH, Na, K, Ca, Cl, haemoglobin, phosphorus, bicarbonate and base excess of blood. Plasma proteins were higher in old dogs than in young dogs (7.1 +/- 0.2 versus 6.5 +/- 0.2 g dl-1). Anion gap was increased in aged dogs; however, no changes were found in unidentified anions. In conclusion, an increase in P(A-a)O2 has been identified in a group of geriatric dogs. No major changes have been found in the acid-base balance of aged dogs.

Structural and ultrastructural study of the myocardium after 24-hour preservation in University of Wisconsin solution

This study deals with myocardial preservation after 24 hours of continuous perfusion with University of Wisconsin (UW) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. Following preservation, the histological images of the myocardium were normal in almost every case. After revascularization, although 50% of the hearts recovered preoperative functional levels, there were relevant histological changes in all of them. These changes consisted of interstitial edema, damage to at least 50% of the mitochondria, presence of contraction bands, loss of intercellular junction structure and vasoconstriction. According to these results, the association of continuous perfusion and UW solution appears to be effective during the ischemic period of prolonged myocardial preservation, but not during reperfusion. Perhaps the proportion of viable hearts could be increased by preventing vasoconstriction.

Occurrence of thermotolerant Campylobacter species in domestic and wild monkeys from Peru

The isolation rate of thermotolerant campylobacters in pet monkeys and wild monkeys was established. Campylobacter spp. were isolated in 31.9% of the first (pet) group, being less frequent (20.9%) in the second (wild) (P > 0.05). In both groups, only biovars I and II of C. jejuni ssp. jejuni and both biovars of C. coli were isolated (Lior's scheme). Campylobacter lari was not isolated. The results show that domestic and wild monkeys can harbour Campylobacter in their intestinal tract and would be considered as reservoirs of these bacteria.

Use of interferon-alpha in laryngeal papillomatosis: eight years of the Cuban national programme

Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-alpha, 12 with recombinant IFN-alpha-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 10(5) IU/kg of weight in children or 6 x 10(6) IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 x 10(4) IU/kg in children or 3 x 10(6) IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.

[Intervention of Campylobacter jejuni subsp. jejuni flagella in the adhesion to cellular cultures: bacteriological and immunological evidence]

The participation of the flagella of a virulent strain (O52) of Campylobacter jejuni subsp. jejuni in the adhesion to HEp-2 cells and their inhibition by means of homologous polyclonal antibodies, monoclonal anti-flagella antibodies and colostral natural antibodies (IgA) was studied. An aflagellated strain (T1) was used as negative control. Adhesion was observed in higher rates with O52 strain (72%) than with T1 strain (27.5%). Polyclonal, monoclonal and colostral antibodies inhibited O52 strain adhesion in more than 70% (p < 0.001). T1 strain adhesion was inhibited only by polyclonal and colostral natural antibodies. Our results suggest that the flagella of C. jejuni subsp. jejuni could participate effectively in the adhesion process. However, the inhibition of T1 strain by polyclonal and colostral antibodies suggests the existence of other binds of adhesins in the bacterial surface.

Isolation of thermotolerant species of Campylobacter from commercial chicken livers

The qualitative and quantitative contamination levels of Campylobacter spp. in frozen commercial chicken livers were assessed. From the 126 samples studied, 117 (92.9%) were positive for Campylobacter spp. C. coli was isolated more frequently (78.6%) than C. jejuni (21.4%). The MPN method showed that Campylobacter contamination levels ranged from 10 to > 230 bacteria/100 ml of liquid exuded by livers.

[Participation of Campylobacter jejuni flagellar epitopes in cellular adhesion]

Using a flagellated (052) and an aflagellated (T-1) strains we studied the participation of flagellar epitopes of C. jejuni in the adhesion to HEp-2 cells in vitro. Strain 052 was significantly more adherent than strain T-1. When adhesion assays were carried out with antiflagella monoclonal antibodies, strain 052 showed inhibition of their adhesive capacity that varied between 64.3 and 92.9%. With an ELISA test it was demonstrated that those monoclonal antibodies were specific and directed exclusively against flagellar epitopes of strain 052 being unreactive with strain T-1. Our results show that flagellar epitopes could participate in the adhesion process suggesting that flagella could be involved in the installation of the infectious process.

Lesions of the medial prefrontal cortex and sexual behavior in the male rat

Lesions of the cerebral cortex near the midline in the frontal region appearing to destroy most of the cingulate cortex and adjacent prefrontal areas had profound effects on male rat sexual behavior. At the first postoperative tests, one week after the lesion, the mount and intromission latencies were extremely long (> 60 min). They continued elevated at every fortnightly test until postlesion week 13, when they were no longer different from controls. However, the proportion of animals that intromitted or ejaculated was reduced at this time. The lesion had a slight effect on the number of intromissions and on the intromission ratio, but did not reliably modify other parameters of sexual behavior in those males that copulated after operation. These data suggest that the medial prefrontal cortex is important for the initiation of sexual behaviour but less so for its execution. It is proposed that the elaboration and/or interpretation of environmental stimuli are rendered deficient by the lesion. Consequently, sexual behavior is activated only with difficulty. This coincides with the arousal hypothesis proposed by Beach [8]. There appears to exist a spontaneous recovery of the mechanisms responsible for the activation of sex behavior because the lesioned group was not different from the sham or intact groups 13 weeks postlesion. Remaining cortical tissue or other brain structures may compensate for the initial deficiencies. However, the lesion's effect on intromission behavior did not diminish with time. This could suggest that possible motor deficiencies produced by the lesion are irreversible.

[Isolation of thermotolerant species of Campylobacter from 2 populations of chickens bred in confinement and at liberty]

The isolation rates of thermotolerant Campylobacter species in free-ranging domestic chickens and confined chickens from Iquitos city, Peru, were determined. Campylobacter spp. were isolated in 54.0% of the former group of chickens, being less frequent (35.0%) in the latter (p < 0.05). Of the classical thermotolerant species, C. jejuni and C. coli were the most frequent. However, the presence C. lari suggests that the chickens might be an important reservoir of this bacterium.

[Physiology of erection]

OBJECTIVE

The present study reviews the mechanism involved in the initiation and maintenance of penile erection.

METHOD

The study reviews the literature on the basic concepts supporting either "magically" or scientifically the erectile mechanism. An anatomo-physiological update is also included (i.e., the main neurological, muscular, and vasculoendothelial phenomena).

RESULTS

Present studies based on the vasoactive action of different drugs have increased the knowledge on the neurological, muscular, and vasculoendothelial phenomena. The cavernous muscular relaxation may start and finish due to the equilibrium between the contractile adrenergic and the relaxing non adrenergic-non cholinergic stimulus through intracellular nitric oxide synthesis. This is an essential phenomenon involved in the entry and "trapping" of blood within the sinus spaces.

CONCLUSIONS

Our knowledge on the erectile mechanisms through neuromediators is increasing. The role of the endothelium in intracellular nitric oxide synthesis and its relaxing effect, will improve our understanding of both physiological and therapeutic phenomena.

[Analysis of the results with Rigiscan in 93 impotent patients]

OBJECTIVE

This study was undertaken to evaluate the performance of the Rigiscan in the diagnosis of sexual impotence.

METHODS

Erectile nocturnal activity was evaluated by Rigiscan in 93 patients consulting for impotence; mean age 56.8 years. Diagnosis and treatment were performed between October, 1990 and May, 1992. Follow up is currently ongoing.

RESULTS

95.1% of the patients with normal recordings had no organic pathology, and 80% of these recordings were observed on the first night of the study. In ruling out organic pathology, the Rigiscan did not have a higher specificity than the report of early morning erection (EME) by the patients (p > 0.05). Seventy three percent of the pathological results on the Rigiscan studies were associated to organic pathology. This test showed a higher sensitivity than the absence of EME (p < 0.01). Although no pathognomonic diagnostic pattern was found, a flat pattern and uncoupling were highly suggestive of organic disorders.

CONCLUSIONS

The Rigiscan is a useful diagnostic tool, especially in patients reporting no EME. Furthermore, the Rigiscan was able to detect almost all the patients with organic pathology.

Effect of the complement system on the sensitivity of Campylobacter jejuni and Campylobacter coli to human blood serum

We determined the sensitivity of five strains of Campylobacter jejuni and C. coli isolated from children with diarrhea and from chicken feces to normal human blood serum (undiluted and at concentrations of 10, 30, 50 and 70%), a hypogammaglobulinemic serum and a complement-deficient serum. Both species were highly sensitive to the bactericidal activity of human serum, regardless of their source. The highest bactericidal activity was observed with pooled fresh normal serum, with bacterial survival rates inversely correlated to serum dilutions. Inactivated serum had the least bactericidal activity. When complement was partially restored to inactivated serum, lower survival rates were observed. The hypogammaglobulinemic-normal complement-containing serum had strong bactericidal activity whereas the normal immunoglobulin-containing but complement-deficient serum had little bactericidal activity. These results suggest that Campylobacter may be able to directly activate complement by the alternative pathway.

Invasive and enterotoxic properties in Campylobacter jejuni and Campylobacter coli strains isolated from humans and animals

Invasive properties of 15 strains of thermotolerant Campylobacter (12 C. jejuni and 3 C. coli) were studied using HeLa cells cultures. In four of them (3 C. jejuni and 1 C. coli), randomly selected, intestinal perfusion experiments were conducted in order to asses enterotoxigenicity. All strains were able to invade HeLa cells. The number of invaded HeLa cells ranged from 3 to 46%. In addition to their invasive properties, the 4 strains used in perfusion experiments were able to induce either a net secretory flux or an impaired sodium transport.

Prevalence of thermotolerant species of Campylobacter and their biotypes in children and domestic birds and dogs in southern Chile

The prevalence of thermotolerant Campylobacter in diarrhoeic and healthy children as well as in dogs, hens, ducks and pigeons was determined in Southern Chile. Campylobacter were found in 34.5% of the faecal samples examined. The isolation rate of Campylobacter in diarrhoeic and healthy children was 16.3% and 6.4% respectively. Despite C. jejuni was always more frequent than C. coli, the latter was isolated with a high frequency (29%) from patients with diarrhoea. C. jejuni and C. coli biotypes I and II were found in healthy and diarrhoeic children and were predominant in all the animals species studied. This may point out towards the possible origin of strains infecting children.

[Clinical, epidemiologic, and microbiologic study of urinary infection in patients with renal transplant at a specialized center in Argentina]

Sixty-four patients were evaluated for urinary tract infection (UTI) during the first six months after renal transplantation. Eighty per cent received the allograft from a living, related donor and 37% were female. The median age was 33.8 years. All the patients received cefazolin as perioperative antibiotic prophylaxis. No prophylaxis was given during the bladder catheterization period, which had a median duration of 5.9 days. Nineteen per cent developed predisposing urological factors (PUF). The incidence of UTI was 41% and 15% of all these patients developed bacteremia from this source. UTI was observed in 50% of the patients without PUF between the 5th and 12th days post-transplantation, and these cases had been detected by the control urine culture performed when the bladder catheter was withdrawn. This group of patients accounted for 14% of all the patients. Recurrence was present in 42% of the patients with UTI (19% had reinfection, 4% relapse and 19% both). They were more frequent in patients with PUF than in the patients without; 78% vs. 24%, respectively (p < 0.05). The overall UTI incidence was also higher; 75% vs. 33%, respectively (p < 0.05). The same was observed for the median number of episodes (3 vs. 1). The organisms most frequently isolated were E. faecalis (21%). E. cloacae (17%), and E. coli (17%). Species prevalence differs from that of other reports, probably due to the different institutional antibiotic management. Since half of the UTI episodes suffered by patients without PUF were associated to bladder catheterization, there is a need to institute antibiotic prophylaxis in our center.