[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.