Effects of subinhibitory concentrations of ciprofloxacin on enterotoxigenic Escherichia coli virulence factors

Eight enterotoxigenic Escherichia coli were studied with the aim of investigating the effect of subinhibitory concentrations of ciprofloxacin on their adherence properties and on the expression of thermolabile enterotoxin. Our data showed that the hydrophobicity on the bacterial cell surface, the hemagglutination properties, and thermolabile enterotoxin production were considerably reduced after treatment with subinhibitory concentrations of ciprofloxacin, suggesting that ciprofloxacin may be capable of decreasing adhesiveness and expression of the thermolabile toxin of enterotoxigenic Escherichia coli. In conclusion, our study supports the concept that subinhibitory concentrations of ciprofloxacin interfere with the process of host-parasite interactions such as adherence and toxin production.

Impact of lactation upon fertility in the New World primate capuchin monkey (Cebus apella)

In the present paper, we have studied the impact of lactation upon fertility in the capuchin monkey, Cebus apella, under laboratory conditions. Nursing females (ten females, 12 postpartum periods) presented lactational amenorrhea (first menses at 159.2 +/- 9.0 vs 42.6 +/- 5.8 days postpartum in five non-nursing females, seven postpartum periods). Plasma estradiol and progesterone concentrations during lactational amenorrhea were lower than those during the follicular phase of the menstrual cycle. Prolactin was higher than in non-nursing females at 31-60 days postpartum. Interbirth interval, studied in three non-nursing (four intervals) and six nursing females (eight intervals) lasted for 349.5 +/- 11.8 and 613.4 +/- 30.8 days, respectively. In non-nursing females, early recovery of the menstrual cycle was followed by a residual infertility (mating but no pregnancy) lasting 152.8 +/- 7.9 days. In nursing females, recovery of the menstrual cycle was followed by an extended residual infertility of 301.5 +/- 22.7 days. Thus, in the capuchin monkey, nursing prolongs the interbirth interval by inducing lactational amenorrhea and extending the residual infertility period.

[Patient assessment of the long-term benefits of surgery in inflammatory bowel disease]

The objective of surgical treatment in ulcerative colitis (UC) and Crohn's disease (CD) differs. Surgery in UC is more aggressive and potentially curative whereas in CD it is more conservative and palliative.

OBJECTIVE

To assess the opinion of patients with inflammatory bowel disease who underwent surgery in the distant past about the results and timing of surgery.

MATERIAL AND METHODS

A total of 50 surgical patients (36 with CD and 14 with UC) who had undergone an intestinal surgical procedure at least one year before. The clinical characteristics of patients and details of surgery procedures were recorded. Also, a personal interview was conducted. Patients were asked about their current clinical status, surgical consequences and their opinion about the appropriate timing of surgery.

RESULTS

Surgery for UC was total proctocolectomy in 85% of patients and it was on an emergency basis in 43% of them. Surgery for UC was partial intestinal or colonic resection, and it was on an emergency basis in 22% of them. Postsurgical complications were more common in UC than CD patients (50% versus 20%; p < 0.05). In CD surgery, recurrence of disease occurred in 78% of patients within a 2.6 years interval. Among UC and CD patients, 71% and 50%, respectively, reported that their presurgical expectatives had been fulfilled (p = 0.17).

CONCLUSIONS

Surgery for UC is associated with an appreciable rate of complications; however, most patients had their expectatives fulfilled with surgery as long-term symptoms were controlled. As for CD, the patient's satisfaction degree was lower than or UC.

Helicobacter pylori eradication prevents recurrence from peptic ulcer haemorrhage

BACKGROUND

Successful eradication of Helicobacter pylori infection clearly modifies the natural history of peptic ulcer disease and prevents further recurrences of duodenal and gastric ulcers. However, there are few prospective studies about actual rates of rebleeding after H. pylori eradication, a highly relevant aspect of management as re-infection, relapse of ulcer disease for other reasons (i.e. anti-inflammatory agents) or idiopathic ulcers unrelated to H. pylori may develop and cause further bleeding episodes.

OBJECTIVE

To determine the incidence of bleeding episodes after eradication of H. pylori infection in patients who had bled from an H. pylori-positive peptic ulcer.

PARTICIPANTS AND INTERVENTIONS

H. pylori-positive patients who bled from a gastric or duodenal ulcer were treated with appropriate triple and/or quadruple therapy. H. pylori eradication was confirmed by urea breath test 4 weeks after treatment. Patients received no further treatment but were followed clinically and additional urea breath tests were performed every 6 months. Endoscopy with antral and corpus biopsies and urea breath test were repeated as soon as patients manifested any dyspeptic symptoms that might signal recurrence.

RESULTS

A total of 103 patients with bleeding duodenal ulcer were included in the study; H. pylori was successfully eradicated in 93 of these patients, who were followed for a median interval of 27 months. The yearly re-infection rate was calculated to be 0.6%. There were no instances of rebleeding in any patients during the follow-up period.

CONCLUSIONS

Even after prolonged follow-up, successful H. pylori eradication prevents rebleeding.

Impact of inflammatory bowel disease on health-related quality of life

Health-related quality of life (HRQOL) has a recognized importance to evaluate, manage and follow patients. Different types of instruments for measuring HRQOL have recently been introduced to evaluate HRQOL in patients with inflammatory bowel disease. Most questionnaires suggest that inflammatory bowel disease has a significant impact in HRQOL. It seems that ulcerative colitis has less profound effects on HRQOL than Crohn's disease and that some differences in HRQOL status are related to some factors such as the severity of the disease. When patients express their concerns, most important worries are related to surgery. Effective medical treatment appears to improve HRQOL. Effects of surgery on HRQOL can probably be different depending on the type of surgical technique and if it is curative or not. Recent studies suggest that inflammatory bowel disease not only impacts on patient's HRQOL but also on their caregivers. Features such as the impact on HRQOL of different disease variables, such as complications or patient personality, the role of medical or surgical treatments on different dimensions of HRQOL, the cost-utility evaluation of therapy are some of the fields that will probably focus the protagonism in the next years.

System to measure the use of the backrest in sitting-posture office tasks

This paper presents an inexpensive and simple system to measure the way of use of the backrest. The system can be also used in field studies. It is based on a set of electrodes which, attached to the subject's back and the backrest, allows the contact area to be measured. A laboratory test was performed to validate the system. In the test the spontaneous use of the backrest in standard office chairs and tasks was studied. Four different types of backrest use have been detected, and it has been shown that they determine the lumbar curvature and pelvic inclination angles, as well as postural mobility. The comfort levels observed in the four types of backrest use were also different. Consequently, the system can be used as an indicator of back posture and comfort.

Asymptomatic infections by diarrheagenic Escherichia coli in children from Misiones, Argentina, during the first twenty months of their lives

Diarrheagenics Escherichia coli are the major agents involved in diarrheal disease in developing countries. The aim of this study was to evaluate the time of appearance of the first asymptomatic infection by the different categories of diarrheagenic E. coli in 44 children since their birth and during the first 20 months of their lives. In all of the children studied, we detected at least one category of diarrheagenic E. coli through the 20 months of the study. 510 diarrheagenic E. coli (33.5%) were obtained from the 1,524 samples collected from the 44 children during the time of the study (31.4% EAggEC, 28.8% EPEC, 27.1% DAEC, and 12.7% ETEC). Neither EHEC nor EIEC were identified. The median age for diarrheagenic E. coli colonization was 7.5 months. The mean weaning period was 12.8 months and the mean age for introduction of mixed feeding (breast fed supplemented) was 3.8 months. A significantly lower incidence of diarrheal disease and asymptomatic infections was recorded among the exclusively breast-fed rather than in the supplemented and non breast-fed infants. For ETEC, EPEC and EAggEC the introduction of weaning foods and complete termination of breast-feeding were associated with an increase of asymptomatic infections.

Prospective cohort study of enterotoxigenic Escherichia coli infections in Argentinean children

In a follow-up study, enterotoxigenic Escherichia coli (ETEC) infections in 145 children from two communities located in northeastern Argentina were monitored for 2 years. The occurrence of diarrhea was monitored by weekly household visits. Of 730 fecal specimens collected, 137 (19%) corresponded to diarrheal episodes. ETEC was isolated from a significantly higher proportion of symptomatic (18.3%) than asymptomatic (13.3%) children (P = 0.04541). Individuals of up to 24 months of age were found to have a higher risk of developing ETEC diarrhea than older children (odds ratio [OR], 3.872; P = 0.00021). When the toxin profiles were considered, only heat stable enterotoxin (ST)-producing ETEC was directly associated with diarrhea (P = 0.00035). Fifty-five percent of the ETEC isolated from symptomatic children and 19% of the ETEC isolated from asymptomatic children expressed one of the colonization factors (CFs) investigated, i.e., CF antigen I (CFA/I), CFA/II, CFA/III, and CFA/IV; coli surface antigens CS7 and CS17; and putative CFs PCFO159, PCFO166, and PCFO20, indicating a clear association between diarrhea and ETEC strains that carry these factors (P = 0.0000034). The most frequently identified CFs were CFA/IV (16%), CFA/I (10%), and CS17 (9%). CFs were mostly associated with ETEC strains that produce ST and both heat-labile enterotoxin and ST. Logistic regression analysis, applied to remove confounding effects, revealed that the expression of CFs was associated with illness independently of the toxin type (OR, 4.81; P = 0.0003). When each CF was considered separately, CS17 was the only factor independently associated with illness (OR, 16.6; P = 0.0151). Most CFs (the exception was CFA/IV) fell within a limited array of serotypes, while the CF-negative isolates belonged to many different O:H types. These results demonstrate that some CFs are risk factors for the development of ETEC diarrhea.

[Antimicrobial resistance among species of Salmonella, Shigella, Escherichia, and aeromonas isolated from children with diarrhea in 7 Argentinian centers]

The increasing levels of resistance of enteropathogenic bacteria against antimicrobial agents present geographic variations. We have analysed the antimicrobial susceptibility of isolates obtained from 4,364 children under 5 years of age with acute diarrhea, in 7 cities of Argentina. Diarrheagenic E. coli exhibited 74.5% of resistance against ampicillin, 64.2% against sulfametoxazole-trimethoprim, and Shigella spp., 62% and 75.6% respectively. Salmonella sp. showed 35%, 14%, 41.8%, 65.4%, 14.5%, and 13.6% of resistance against ampicillin, chloranfenicol, sulfametoxazole-trimetoprim, sulfadiazin, gentamycin, and fosfomycin respectively. These values are higher than the ones observed in developed countries. Aeromonas showed significantly lower resistance percentage. Important differences in our country were observed, consequently, local trials should be carried out in order to apply corrective measures.

The impact of delaying gastric emptying by either meal substrate or drug on the [13C]-urea breath test

OBJECTIVE

Optimal [13C]-urea breath test (UBT) conditions for diagnosis of Helicobacter pylori infection are still being fine-tuned. In the present study we investigated the impact of delaying gastric emptying by different meal substrates or L-DOPA, a drug known to induce gastric stasis, on the performance of the [13C]-UBT.

METHODS

A total of 115 patients participated in the study. On two consecutive days, participants ingested [13C]-urea (100 mg) 10 min after either 270 ml of a mixed formula meal (1 Kcal/ml) or an equivalent amount of tap water. In 11 participants two additional tests were performed with or without oral 500 mg L-DOPA given 30 min before [13C]-urea load. The 13C/12C ratio in a basal breath sample was compared with ratios in samples collected 30 and 60 min after [13C]-urea. Histological assessment of H. pylori presence in antral biopsy served as reference standard.

RESULTS

Formula UBT showed excellent specificity (100% at 30 and 60 min) and good sensitivity (97% at both time intervals), whereas water UBT had the same specificity but slightly lower sensitivity (94% at 30 min and 73% at 60 min). In formula UBT, 13C/12C ratios were higher at 60 min than at 30 min (21.7+/-2 vs 17.7+/-1.8 per thousand respectively, p < 0.01, whereas in water UBT 13C/12C ratios were higher at 30 min than at 60 min (13.9+/-1.5 vs 8.4+/-0.09 per thousand respectively, p < 0.01). Pretreatment with L-DOPA did not modify either the sensitivity or the specificity of the UBT.

CONCLUSIONS

The performance of the [13C]-urea with a formula meal may not be improved by pharmacologically delaying gastric emptying. A short, water-based test may be a sensible approach to worldwide standardization of the [13C]-UBT for H. pylori infection.

Changes in hypothalamic calmodulin concentration induced by perinatal hormone manipulation in the rat

Calmodulin (CaM) presence and concentration was determined (RIA) in the rat hypothalamus (2, 6, 12, 24 h and 90 days after birth) in vehicle-treated animal (controls), in testosterone propionate (TP)-treated females (30 microg/rat subcutaneously 1 h after birth) and in tamoxifen-treated males (200 microg/rat subcutaneously 1 h after birth). CaM concentration, either as total content/hypothalamus or as concentration per mg ww, was significantly higher in both male and female adult rats than in newborn subjects. CaM concentration/mg protein increased with age, being two times higher in adult males and greater than three times higher in adult females than in their respective newborns. Two, 12, and 24 h after birth CaM concentration was significantly lower in control females than in control males. This relation was reversed in adults in which CaM concentration was higher in females. The application of TP to the females and tamoxifen to the males, induced a significant decrease in CaM/mg protein, both in the newborn (2 and 6 h) and in the adult animals. In adults, treated females had CaM concentrations similar to those found in control males. Our data suggest: first, a lasting effect of newborn hormonal treatment upon the CaM concentration in rat hypothalamus; second, that CaM is preferentially synthesized in the adult female hypothalamus, indicating an important role of this protein in female reproductive function.

Acute pancreatitis as a triggering factor for thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) constitutes a poorly understood multisystemic disease of vascular origin that may involve any organ by thrombotic occlusions of the small vessels. Treatment with plasmapheresis is the best therapeutic option at this present moment. Involvement of the pancreas is a well established feature of this disease, which has generally been interpreted as a consequence of pancreatic vascular compromise. However, there are a few cases in the literature in which the clinical signs of TTP developed well after the clinical and laboratory demonstration of acute pancreatitis (AP). Therefore, the possibility of pancreatic inflammation as a triggering factor of TTP may need to be considered. This cause-effect relationship between AP and TTP remains unclear. We report a patient with chronic pancreatitis presenting with two episodes of TTP, triggered by acute relapses of pancreatitis. TTP may, thus, constitute a hematological complication of AP. We discuss the pathophysiological aspects of this association, along with therapeutical options.

Influence of the smoking habit in the surgery of inflammatory bowel disease

The smoking habit is a key factor in the development of inflammatory bowel disease (IBD), but little information exists as to the relationship between smoking habit, the need of surgery and its complications.

OBJECTIVES

To investigate the relationship between smoking habit, the need of surgery, their complications and clinical recurrence after surgery in Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We studied a group of 62 patients (22 with UC and 40 with CD) with previous surgery. We analyzed the clinical and surgical characteristics of the disease. Smoking habit was established by a personal interview. This group of patients was compared with another control group of 202 patients (133 with UC and 69 with CD) with IBD without previous surgery.

RESULTS

Smoking habit was similar between operated and non-operated patients for both UC (73% and 80% non-smokers) and CD (67% and 63% smokers) The number and type of complications after surgery were not related with smoking habit. In CD patients, although the recurrences did not depend on the smoking habit, they did occur earlier in smokers than in non smokers (83.6 +/- 21 vs 155 +/- 50 weeks, p = ns).

CONCLUSIONS

The smoking habit does not seem to influence significantly the need of surgery and post surgical development of IBD, although in CD the smokers seems to present recurrence before non smokers.

Diurnal changes in light intensity inside the pregnant uterus in sheep

Penetration of light into the pregnant sheep uterus was studied in 9 ewes, gestational ages 40 to 142 days (term 147 days). Light sensors were placed inside the pregnant horn and over the flank skin overlying the position of the uterine horn. To perform the experiments, the ewes were placed in a study cage outdoors and light sensors were connected to a luxometer. Simultaneous measurements were obtained from the intrauterine and the external sensors in the shade at noon. The amount of light detected inside the uterus increased with gestational age from two lux at 40 days to 51.1 +/- 16.5 (n = 5) lux at 142 days (0.2 and 5.4% of the amount of light detected at the maternal flank). Measurements through the 24 h were done in four pregnant ewes at 142 days gestation under natural photoperiod (13.5 light:10.5 dark). In these experiments, the intensity of intrauterine light changed through the 24 h, reflecting the changes in the intensity of the sunlight. Maximal intrauterine light values were observed at noon, corresponding to 4.7% of incident light. Small but detectable values were observed at 0900 and 1800 h. Our data show that, at mid gestation, light reaches the pregnant uterus and that, at late gestation, changes in intrauterine lighting throughout the 24 h are present reflecting the changes in external daylight. Therefore the sheep fetus is exposed to light-dark transitions at dawn and dusk, and to a peak of light at midday.

[Gastric ulcers as the only manifestation of infection by cytomegalovirus in immunocompetent patients]

Gastritis is an infrequent manifestation of infection by cytomegalovirus (CMV) in a healthy host. This complication is usually associated to a mononucleosic syndrome during the course of a disseminated infection. Macroscopically, it presents with edema and mucosal congestion, multiple erosions or ulcers. Histologic examination of the endoscopic biopsies allows the etiologic diagnosis to be established in most cases. In immunocompetent patients the clinical course of gastritis by CMV is usually self-limited. We herein present two immunocompetent patients with gastric ulcerous disease as the only manifestation of CMV infection. Both patients required antiviral treatment due to refractoryness to the antisecretor treatment and one case evolved to pyloric stenosis requiring surgery.

Effects of smoking on the presentation and clinical course of inflammatory bowel disease

OBJECTIVE

To evaluate the influence of regular smoking on the presentation and clinical course of inflammatory bowel disease.

METHODS

We performed a case-control study interviewing 160 inflammatory bowel disease patients (63 with Crohn's disease (CD) and 97 with ulcerative colitis (UC)) and 140 first-degree relatives as controls. The risk of developing the disease relative to a smoking habit was calculated as the odds ratio. Furthermore, to evaluate the influence of smoking on the subsequent course of inflammatory bowel disease, we performed a multivariate analysis that included pertinent variables such as the need for surgery, number of hospitalizations and relapses.

RESULTS

The pattern of smoking in UC patients was different from that in CD patients. In UC there was a significant predominance of non-smokers and ex-smokers (P = 0.02), whereas smoking habits in CD were not different from those in controls. Giving up smoking was a risk factor to develop UC (odds ratio: 3.2, P = 0.02). In UC, non-smokers and specially ex-smokers need surgery more frequently than smokers (P < 0.01). Otherwise the relapse/year index was not influenced by smoking. In CD there was a non-significant association between smoking habits and the various clinical parameters analysed. UC patients who begin smoking after diagnosis of the disease present a significant reduction in the number of recurrences.

CONCLUSION

Smoking habit significantly affects the presentation and clinical course of UC, whereas in CD, a smoking habit does not have any apparent influence on the disease.

Seasonal influence in exacerbations of inflammatory bowel disease

Several epidemiological studies have suggested a possible seasonality in the presentation and course of inflammatory bowel disease. Our aim was to investigate whether in our area there is a seasonality in the presentation and evolution of inflammatory bowel disease. In this retrospective evaluation 255 patients were included, of whom 141 patients were diagnosed with ulcerative colitis and 114 with Crohn's disease according to conventional criteria, with histological confirmation in 225 patients. Relapse was defined as the development of symptoms that required an increase or change in the usual treatment. Periods of activity were related to the month and grouped within one of four seasonal periods: December to February, March to May, June to August and September to November. Bouts of ulcerative colitis and Crohn's disease were most frequently diagnosed in the period June to August (p < 0.05). Both diseases showed similar seasonality, and analysis of the 305 attacks did not show any significant trend. In conclusion, inflammatory bowel disease begins more frequently in the period June to August, but its course does not show consistent seasonal variations.

[Toxigenic Vibrio cholerae: identification of the ctxB gene]

BACKGROUND

A specific probe was designed to identify part of the genetic sequence of the ctxB gene which encodes for the B subunit of the cholera toxin by polymerase chain reaction (PCR) which amplifies a 318 bp segment of the ctxB gene. Marked with P32, we used this probe for colony hybridization which is a technique for identifying the production capacity of subunit B of strains of Vibrio cholerae O1 from different outbreaks in South America (Perú 1992 and Ecuador 1993-1995) and from, collection strains. This probe was tested for the identification of the ctxB gene in Vibrio cholerae O139.

METHOD

Thirty-eight phylogenetically related strains were studied: 24 V. cholerae O1, 4 V. cholerae non O1, 5 Aeromonas, 4 Plesiomonas and 1 Escherichia coli.

RESULTS

The probe demonstrated to be useful for the identification of the ctxB gene (which codifies for the subunit B of the cholera toxin) in 24 strains of Vibrio cholerae O1 and in the Vibrio cholerae O139 strain. The ctxB gene was not detected in the remaining strains pertaining to the Vibrio cholerae non O1 species (non O139), Plesiomonas, Aeromonas spp. and E. coli. The specificity of this product was not demonstrated since no signal of unspecific hybridization appeared with phylogenetically related strains such as Escherichia coli K88 (LT+) and Aeromonas hydrophila ATCC (LT+), producers of the thermolabile LT toxin. It is important to indicate that the ctxB gene in V. cholerae O139 has been identified, for the first time, with our probe and thus it may be said that all the strains which have genetic codification for CT up to now may be identified.

CONCLUSIONS

We conclude that the system herein described provides advantages over the immunologic and biologic methods for evaluating a large number of samples in a short time and with excellent specificity and sensitivity which are important in the diagnosis and the epidemiologic surveillance of the disease.

Development of a radioimmunoassay for Cebus apella prolactin

Prolactin (PRL) is a pituitary hormone that plays important roles in mammalian reproductive physiology, specially lactation. The regulation of PRL secretion shows important species differences. To study PRL regulation in a subhuman primate, the Cebus apella, we developed an heterologous radioimmunoassay using an antibody against rhesus PRL (anti-m5PRL) and a Cebus apella pituitary extract as PRL standard. The assay has a sensitivity that allows measurements of cebus PRL in small amounts of Cebus apella plasma obtained from animals in different physiological conditions. Plasma cebus PRL concentrations (+/-SEM) varied in different reproductive stages. PRL concentration in adult Cebus apella females that have regular menstrual cycles (161.6 +/- 15.0 mIU/ml) was similar to that found in adult (100.3 +/- 7.6 mIU/ml) and prepuberal males (101.2 +/- 3.9 mIU/ml). PRL concentration was higher in pregnant (677.8 +/- 11.8 mIU/ml) and in nursing (625.0 +/- 47.0 mIU/ml) Cebus apella females than in 15-d post-partum non-nursing (369.0 +/- 19.0 mIU/ml) and cycling females. PRL concentration in Cebus apella newborns (719.0 +/- 49.2 mIU/ ml) was similar to that found in pregnant and nursing females, and higher than in the other females as well as adult and prepuberal males. These differences in PRL concentration in different physiological conditions are similar to that observed in humans and other primates. A PRL response to thyrotropin releasing hormone (TRH) was demonstrated in 2 nursing Cebus apella females, similar to the response found in nursing woman and rhesus. Altogether, the data presented support the proposal that the assay developed to measure PRL in Cebus apella is an adequate tool to study the physiology of PRL in this species.

Prospective study of enteropathogens in two communities of Misiones, Argentina

Children under five years of age, from two communities of different socio-economic strata (97 from Zaiman and 55 from Las Dolores) were examined epidemiologically during 2 years, by means of quarterly visits of the working team, who carried out the collection of faecal samples. During the study, one or more enteropathogens were identified in 73.9% of samples in children from Zaiman and in 58.3% of the samples from Las Dolores, being associated to diarrhoea in 70.5% and to asymptomatic infections in 65.7%. The number of diarrheic episodes was higher in Zaiman (15.45%) than in Las Dolores (12.35%), being more frequent in the spring-summer seasons. In Zaiman, the bacterial enteropathogen proportion was relevantly higher (p < 0.005) in children with diarrhoea, whereas the presence of parasites was more frequent in asymptomatic children (p < 0.01). Rotavirus had an even distribution within diarrheic and asymptomatic children. In Las Dolores, no relevant differences were found in the detection of enteroparasites between diarrheic and asymptomatic children. Mixed infections were detected; enterotoxigenic Escherichia coli (ETEC)-rotavirus and ETEC-parasites being the most frequent ones. ETEC was involved in 85% of these infections. These data, together with the high enteropathogen carriage, suggest an elevated level of environmental contamination. The latter plays an important role in diarrheic diseases, and added to the most extreme poverty, it affects children's lives.

[Acute pancreatitis in cystic fibrosis]

Cystic fibrosis is the most prevalent hereditary disease in the Caucasian race. It is a multisystemic alteration that affects the quality and quantitative properties of exocrine secretions. The pancreas develops a progressive atrophy causing steatorrhoea and nutritive deficiencies. Acute pancreatitis is an unusual complication. The pancreatic atrophy prevents the inflammatory response. Published series suggest that pancreatitis in 0.5%, including patients without pancreatic insufficiency. We present two cases with cystic fibrosis, with and without pancreatic insufficiency, who developed acute pancreatitis.

Effect of constant light on fetal and maternal prolactin rhythms in sheep

A 24-h rhythm of plasma PRL is present in fetal sheep. This rhythm is synchronized to an environmental clue (zeitgeber). We determined whether the light-dark cycle (L:D) is a zeitgeber for the fetal PRL rhythm and, if so, whether the mother might convey this zeitgeber to the fetus. We kept nine ewes (twin pregnancies) in constant light (L:L) and five ewes (singleton) in 14:10 L:D from 110 days gestation. Fetuses and mothers were catheterized at 119 days gestation. Blood samples were taken hourly for 24 h after 16 days under L:L or L:D. A mean 24-h rhythm of PRL was found (by RIA) in fetuses under L:D, but not in those under L:L. However, fetuses under L:L showed individual 24-h PRL rhythms (cosinor analysis) whose acrophases were distributed around the clock. Nonsynchronized rhythms persisted after 23 and 30 days of L:L. Acrophases of PRL rhythms within a set of twins were closer than those between sets, suggesting that twins were responding to a common signal. These findings indicate that the L:D cycle is a zeitgeber for the PRL rhythm in fetal sheep and suggest that the mother might convey the zeitgeber.

Adverse reactions to contrast media in CT: effects of temperature and ionic property

PURPOSE

To assess the severity of adverse reactions to contrast media in outpatient computed tomographic (CT) examinations in a conventional clinical setting.

MATERIALS AND METHODS

In 4,936 patients, CT was performed with four protocols: ionic contrast medium with sodium meglumine as the cation (in one protocol, contrast material was warmed to 35 degrees C before injection; in another protocol, it was administered at ambient temperature); warmed, ionic contrast medium with nonsodium pure meglumine as the cation; and warmed, nonionic iopamidol.

RESULTS

Adverse reactions to ionic contrast material statistically significantly decreased (P<.05) when it was warmed before administration. Reactions to ionic contrast media without a sodium cation were statistically significantly fewer (P<.001) than reactions to those with a sodium cation. In all protocols, pediatric patients had fewer reactions than adult patients.

CONCLUSION

In outpatient CT examinations, nonionic, warmed contrast medium was the best option because no severe reactions resulted from its use. Prevalence of adverse reactions was comparable to that in controlled randomized studies.

[Changes in the epidemiology of gastric cancer in the last 15 years]

AIM

To determine whether the epidemiological profile of gastric cancer is changing in our patient referral area.

EXPERIMENTAL DESIGN

We have compared the incidence rates of gastric cancer in our Hospital in two three year periods (1975 to 1977 and 1990 to 1992). Gastric cancer was diagnosed by endoscopy or surgery and confirmed histologically. Incidence rate was obtained calculating the ratio (cases of gastric cancer)/ (patients assisted at the hospital) for each period.

RESULTS

522 patients were identified in the first period, and only 255 in the second. Then, the overall incidence fell from 96 x 10(5) to 37 x 10(5). In both periods a male predominance, with a sex ratio male/ female of 1.9 in the first period and 1.6 in the second, was observed. The mean age was also similar in both periods: 61 years (range 20-89) and 65.5 (range 28-90) respectively. Adenocarcinoma was the predominant neoplasm in both periods (98% and 95% respectively). There was also a predominance of antral tumors with a slight decrease of their incidence in the later series (ratio antrum/other gastric sites) from 1.6 to 1.1 respectively (p = 0.07).

CONCLUSIONS

Although gastric cancer is still very common, its incidence in our referral area is decreasing. In addition, the characteristic antral predominance also seems to be decreasing. It remains to be established whether the changing pattern we have observed is related to environmental variation.

Diminished luteinizing hormone biopotency in breastfeeding women

The effect of nursing on plasma luteinizing hormone bioactivity (B-LH) and immunoactivity (I-LH) was assessed at 4 and 6 months post partum in fully nursing women who experienced their first bleeding between months 5 and 6 post partum (n = 6, short amenorrhoea) or after the month 6 (n = 10, long amenorrhoea). Controls were 10 non-nursing fertile women. Blood samples were drawn twice weekly at month 4 post partum and at month 6 post partum. In the nursing women who were cycling at month 6 and in non-nursing women samples were drawn during the follicular phase. I-LH was measured by a time resolved immunofluorometric assay (DELFIA) and B-LH by the mouse Leydig cell assay. Nursing decreased B-LH more than I-LH resulting in a relationship between B-LH and I-LH different to that of non-nursing women (B-LH = 2.84 x I-LH-0.16 and B-LH = 4.27 x I-LH + 3.11 respectively, P < 0.05, by likelihood test). Plasma B-LH or I-LH were similar in nursing women with short or long amenorrhoea. In conclusion, nursing alters the quality of circulating LH, however, the decreased LH steroidogenic potency does not play a role in determining the duration of lactational amenorrhoea.

Antibody responses against Escherichia coli heat-labile toxin and colonization factor antigens I and II in Argentinian children

Serum antibody responses against Escherichia coli heat-labile enterotoxin (LT) and colonization factor antigens (CFAs) I and II were studied in 84 children < 5 years old living in two communities. These villages differed in the quality of their drinking water. Children from both communities developed significantly increased antibody titers against LT and CFA/II but not against CFA/I during 3 months of follow-up. The magnitude of the anti-LT response was significantly higher in children from Zaiman than in those from Las Dolores. Antibody titers rose to maximum levels during the second year of age and reached relatively constant levels in children aged 2-5 years, probably due to repeated exposure to enterotoxigenic E. coli strains. Antibody levels of 30 children were followed for 2 years; increases in anti-LT and anti-CFA titers varied in the different age groups.

Differing responses of plasma bioactive and immunoreactive follicle-stimulating hormone and luteinizing hormone to gonadotropin-releasing hormone antagonist and agonist treatments in postmenopausal women

Plasma bioactive (B) and immunoreactive (I) FSH and LH were measured every 10 min for 8 h in the same postmenopausal women in a three-phase study: 1) during normal pulsatile gonadotropin secretion (basal study; n = 8), 2) 8 h after a single injection of a GnRH antagonist (5 mg Nal-Glu, sc; n = 5), and 3) 21 days after a GnRH agonist injection (D-Trp6, 3.75 mg depot preparation, im; n = 7). I-FSH and I-LH were measured by monoclonal antibody immunoradiometric assays. B-FSH and B-LH were measured in selected samples with the immature rat granulosa cell and mouse interstitial cell assays, respectively. Significant pulsatility of B- and I-FSH and LH was demonstrated in the basal samples, but only the B/I ratio of LH was slightly elevated within the secretion peaks. After GnRH antagonist treatment, I-FSH decreased from a mean pretreatment level of 55.7 +/- 7.8 IU/L by 26% (P less than 0.001), and B-FSH from 313.8 +/- 61.9 IU/L by 44% (P less than 0.01). The B/I ratio decreased from 6.4 +/- 1.7 to 4.5 +/- 1.0 (P less than 0.05). After agonist treatment, the I- and B-FSH levels decreased by 92% and 83% (P less than 0.0001), respectively, but the B/I ratio increased to 17.3 +/- 4.7 (P less than 0.05). The concentrations of I- and B-LH decreased by 75% and 80%, respectively (P less than 0.001), after antagonist treatment. After agonist treatment, I-LH decreased by 92%, and B-LH by 93% (P less than 0.0001). No changes in the B/I ratios of LH were found after either treatment. In conclusion, no changes were found in the quality of circulating LH during the treatments, whereas the antagonist treatment decreased and the agonist treatment increased the B/I ratio of FSH. These findings provide further evidence that the qualitative responses of FSH and LH to treatment with the same GnRH analog are different, and that the suppressive mechanisms of GnRH antagonist and agonist action on gonadotropin secretion are different.

The retino-hypothalamic tract is involved in prolactin regulation in fetal sheep

To investigate the role of the retino-hypothalamic tract on fetal prolactin regulation, we examined the effect of ocular enucleation on fetal plasma prolactin. Eleven fetuses of Suffolk ewes were chronically catheterized during fall, and six of them were subjected to bilateral ocular enucleation. All ewes were kept at 12h:12h light:dark cycle (lights on at 0800 and off at 2000). The experiments were performed 5-9 days after surgery (GA control fetuses 125 +/- 1.5, optical enucleation 121.3 +/- 1.5 days). Blood samples were taken from fetuses hourly around the clock, and plasma prolactin and cortisol were measured by radioimmunoassay (RIA). Luteinizing hormone (LH) and Growth hormone (GH) were measured in pooled plasma samples from control and enucleated fetuses by RIA. Average plasma prolactin was 5-fold lower in enucleated than in control fetuses (9.6 +/- 0.5 and 54.2 +/- 3.3 ng/ml, SEM; P < 0.005). Both control and enucleated fetuses presented circadian rhythm of prolactin with acrophase between 1400 and 1830 h. An enucleated fetus was tested for response of prolactin to TRH. Prolactin increased as described in the literature. There was no change in plasma concentration of cortisol, LH or GH after ocular enucleation. Our data indicate that the optical pathway participates in prolactin regulation in the fetal sheep.

[Hospital crisis and the hospital of the XXI century]

The present hospital situation and a projection for the XXIth century, the national and international information, is analyzed. Outstanding characteristics include better health indicators and an explosive growth of costs due to technological advance and health insurance. Inadequate use of resources is noted. The state expense in public health was greatly decreased during the Chilean military government who privileged private investment. At present, the public sector counts 184 hospitals, 373 outpatient clinics and 1053 rural health posts and takes care of the health needs of 80% of the population. There has been no increase in expenses in the public sector compared to a 150% increase in the number of beds in the private sector. Decentralization, a redefinition of the health care model, an investment program and better administration are needed to improve the situation long-term. The health system and levels of health care as well as a model for hospitals in the coming century are described.

Detection of two atypical rotaviruses in the province of Misiones, Argentina

Out of 317 human gastroenteritis cases studied between August 1988-August 1989, two atypical antigenically distinct rotaviruses (pararotaviruses) were detected in faecal samples among 19 rotaviruses shedding children from Misiones province, North-Eastern Argentina. A 1 3/4 year old girl a 3 years old boy, both with vomiting and normal temperature, shed these atypical rotaviruses. Their morphology by electron microscopy was identical to other rotaviruses; they contained 11 double-stranded RNA segments detected by polyacrylamide gel electrophoresis and failed to react with the antibody directed against the rotavirus group specific antigen (Rotazyme II ELISA). The electrophoretic migration of these RNAs (electropherotype) in polyacrylamide gels did not coincide with the typical pattern of distinct size classes observed in most human rotaviruses reported, instead, they appeared to be related to patterns of rotaviruses group C.

Effect of a melatonin implant on the circadian variation of plasma prolactin and rectal temperature in newborn sheep

Plasma prolactin and rectal temperature show a circadian rhythm in newborn sheep raised under continuous light. Melatonin lowers the concentration of plasma prolactin but it is not known if it affects its circadian rhythm. To detect whether melatonin acts on the circadian system we studied the effect of a subcutaneous melatonin implant in the circadian rhythms of prolactin and rectal temperature in newborn lambs raised under continuous light. We placed catheters in the pedal artery and vein in 9 newborn lambs (2-5 days of age). A subcutaneous melatonin implant was placed in 4 of the lambs at 9-12 days of age. Blood samples and rectal temperature measurements were obtained hourly for a period of 24 h, 11-15 days after the implant, at 20-27 days of age. To avoid interferences of heparin in our melatonin assay, serum melatonin concentration was measured before and during the implant in three additional newborns. Prolactin and melatonin were measured by RIA. Melatonin concentrations were 52.8 +/- 45.9 pg/ml (day) and 315.5 +/- 77.0 pg/ml (night) before treatment (SEM, P less than 0.001), and increased to 594.1 +/- 54.5 pg/ml after placing the implant (there was no difference in melatonin concentration between day and night during the time that the implant was in place). Melatonin had no effect on rectal temperature or its rhythm, but decreased basal plasma prolactin concentration (control: 97.5 +/- 11.3 ng/ml; treated: 25.1 +/- 2.4 ng/ml, P less than 0.001) and abolished the prolactin circadian rhythm, (Cosinor analysis): control: log prolactin (ng/ml) = 1.8 + 0.26 cos 15 (t - 11.16), p = 0.05; treated: log prolactin (ng/ml) = 1.2 + 0.14 cos 15 (t - 9.43), P = 0.36.

[Deficiency of prostacyclin stimulating factor in type I diabetes mellitus. Correlation with the duration of the disease]

The prostacyclin stimulating plasma factor (PSPF) was studied in 40 children affected by insulin dependent diabetes (type I), using smooth muscle cells of rat aorta as substrate. The patients were divided into three groups according to the duration of the disease; recently diagnosed patients (n = 10), patients with less than 5 years of evolution (23 cases), and patients with more than 5 years duration (n = 7). The most significant data were that all the patients with more than 5 years duration had decreased PSPF with values below I SD (p less than 0.001). No statistically significant differences were found among the group with less than 5 years duration, recently diagnosed patients and the normal control group. Neither could a correlation be found between the value of PSPF and the dose of insulin required by each patient, or the rate of hyperglycemia, triglycerides, cholesterol and Hb A1C.

Deficient activity of prostacyclin stimulating plasma factor (PSPF) in newborns

The activity of PSPF was studied in 38 normal newborns. The production of 6-keto-PGF1 (PGI2 stable metabolite) after stimulation with cord blood plasma, 0.72 +/- 0.50 pmol/10(5) cells, was lesser than after stimulation with plasma from 2-3 years old children, 3.00 +/- 0.89 pmol/10(5) cells (p less than 0.01), or from adults, 7.74 +/- 5.00 pmol/10(5) cells (p less than 0.001). No differences were shown during neonatal period. The presence of a circulating inhibitor factor in newborns was dismissed by mixed cultures. The behaviour of neonatal plasma after consecutive stimulations with AA was similar to adult plasma response. We proved that newborns show a deficient capacity to stimulate PGI2, which is not due to circulating inhibitor factor, and we think that this deficiency is due to a weaker action of stimuli, rather than to an immaturity.

The circadian variation of prolactin in fetal sheep is affected by the seasons

Plasma PRL concentration shows a circadian variation in fetal and adult sheep. In the adult sheep the presence of this variation depends on the season. In this paper we investigated whether season affects the presence of the circadian variation of PRL in the fetal sheep. To that effect we measured plasma PRL concentration every 2 h for 24 h during summer, fall, and winter in three groups of fetal sheep whose gestational ages ranged from 125-133 days. Mean (+/- SEM) fetal plasma PRL concentrations were 352.8 +/- 65.0 ng/ml during summer (n = 6), 98.7 +/- 12.9 during fall (n = 8), and 10.5 +/- 2.6 during winter (n = 4). A 24-h variation of plasma PRL was detected during summer [PRL (ng/ml) = 352.8 + 85.2 cos 15 (t - 18.5); P = 0.007] and fall [PRL (ng/ml) = 98.7 + 26.6 cos 15 (t - 23.6); P = 0.041] but not during winter. The mesor and amplitude of the variation are higher in summer than in fall, and the acrophases differ by 5 h, taking place at dusk in summer and close to midnight in fall. These findings show that in fetal sheep, PRL responds to seasons in utero. The signal triggering this response is most likely photoperiod.

Fetal prolactin levels respond to a maternal melatonin implant

Seasonal PRL changes in adult sheep are controlled by photoperiod. The ability to detect photoperiod is mediated by the pineal gland through melatonin secretion. A rhythm in plasma melatonin has been described in fetal sheep. In this work we investigated whether the fetus responds to changes in circulating levels of melatonin. Fetal plasma PRL was measured every 2 h for 24 h, 7 days after the mother had received a sc Silastic implant containing approximately 1 g melatonin. Control fetuses received an empty implant. Melatonin is slowly released from implants, and it is known to cross the sheep placenta. Fetal plasma melatonin increased 10-fold after the implant. Plasma PRL in fetuses treated with melatonin was a third of that of control fetuses. Fetal plasma PRL concentrations were 56.6 +/- 5.7 ng/ml (mean +/- SE) in control and 18.1 +/- 2.7 ng/ml 7 days after the melatonin implant. We conclude from these data that the ability to respond to melatonin is present in sheep during fetal life.

Ontogeny of the circadian rhythm of cortisol in sheep

In this work we investigated the ontogeny of the rhythm of plasma cortisol in sheep. Plasma cortisol was measured by radioimmunoassay in blood samples obtained every 1 or 2 h, for periods of 24 or 48 h, in 13 fetal sheep (124-140 days of gestation; 130.6 +/- 1.5, mean +/- SE) and in 23 newborn (5-39 days of age). To this end, indwelling polyvinyl catheters were implanted into the femoral artery and vein in all animals. The presence of rhythm was determined by Cosinor Analysis. Newborns were separated into four groups. Group 1, newborns younger than 15 days of age (7.9 +/- 0.7 days), and Group 2, newborns older than 15 days of age (25.4 +/- 2.3), were raised under nyctohemeral conditions (12L:12D). Group 3, newborns younger than 15 days of age (11.4 +/- 0.9 days), and Group 4, newborns older than 15 days of age (22.0 +/- 1.2 days), were raised under constant light conditions. A 24-h rhythm of plasma cortisol (F) was observed in newborns over 15 days of age under both nyctohemeral: F (ng/ml) = 16.1 + 7.6 cos [15 (t-12.9)], (p = 0.01, n = 8) and constant light conditions: F (ng/ml) = 17.1 + 3.9 cos [15 (t-7.9)], (p = 0.02, n = 5). No rhythm was observed in fetal sheep or in newborn sheep younger than 15 days of age under nyctohemeral or constant light conditions.

[The first isolations of Salmonella Zaiman in humans]

This paper describes the first three Salmonella Zaiman cases in children of more than one year old with acute infectious diarrhoea of less than seven days evolution, in the Pediatric Department of R. Madariaga Hospital in Posadas, Misiones. This sero-variety was isolated by hemoculture in an 11 year old girl with urinary infection and sepsis. This Salmonella is a new sero-variety isolated from Zaiman river which flows through suburbs of Posadas.

Ontogeny of the circadian variation of plasma prolactin in sheep

The ontogeny of circadian rhythms is unknown. The newborn sheep has a circadian rhythm of temperature; to study the ontogeny of other rhythms, we examined the 24-h variation of plasma prolactin concentration in fetal and newborn sheep. To this effect, we measured plasma prolactin concentration in chronically catheterized fetuses (n = 7) and in newborn lambs raised under short day nycthemeral (12 light:12 dark, n = 13) or constant light conditions (n = 5). Indwelling catheters were implanted into the jugular vein and carotid artery of late gestation fetuses (0.9 gestation) and newborns (5-29 days old). Experiments were performed 4 or more days after surgery. Lambs were kept in a canvas sling and were fed cow's milk either by mouth or through a nasogastric catheter at established time intervals. Haematocrit, pH, and blood gases were measured before and after the experiments in all cases and remained within normal values. Lights were on and room temperature was maintained constant during the whole experiment. Samples were obtained every 1-2 h for 24 h in fetuses and newborn lambs under nycthemeral conditions and every hour for 48 h in newborn lambs kept under constant light. Plasma prolactin was measured by radioimmunoassay. The presence of a 24 h rhythm was determined by Cosinor analysis. Fetuses, aged 129 +/- 6 days (SD) n = 7, showed a variation in plasma prolactin concentration with a period of 24 h that fits the equation: plasma prolactin (ng ml-1) = 97.0 + 15.4 cos 15 (t-23.0), P = 0.035.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian variation of rectal temperature in newborn sheep

In adult animals, body temperature shows a 24 h rhythm that is endogenously generated. We examined the existence of 24 h rhythms of temperature in 10 newborn sheep. Four newborns, aged 5 to 28 days were kept with their mothers under nycthemeral conditions, and the remaining 6 lambs, aged 21 to 43 days, were kept with their mothers in constant light from day 3 after birth. Experiments were performed with both groups of lambs in the laboratory. Additional experiments were performed with the 6 lambs kept under constant light while they were in the pen with their mothers to rule out artifacts due to manipulation or artificial feeding. During the experiments done in the laboratory, the lambs were kept blindfolded in a canvas sling and were fed baby formula approximately every four hours (lambs kept under nycthemeral conditions) or every hour (constant light lambs). Lights were on in the room during the whole experiment. Temperature in the room was maintained at 18 +/- 0.1 degrees C (mean +/- SEM). In the experiments done in the pen, animals remained with the mother and room temperature was not controlled. In all experiments, rectal temperature was hourly measured for 24 h with a thermocouple inserted in the lamb's rectum and connected to a Philipp Schenk digital recorder. Lambs kept under nycthemeral conditions show a variation of mean rectal temperature (t degree) with a period of 24 h, that fits a cosine function (P less than 0.001): Rectal t degree (degree C) = 40.6 + 0.4 cos [15 (t-16.22)]. The mesor is 40.6, the amplitude 0.4, and the acrophase expressed in h is 16.22 (n = 4). Lambs kept under constant light show a variation of rectal temperature with a period of 24 h, independently of whether the measurements were done in the laboratory or in the pens. The acrophases varied widely in these animals, when the acrophase were synchronized so theta = 2400, mean rectal temperature showed a variation with a period of 24 h that fits the equation (P less than 0.001): Rectal t degree (degree C) = 39.5 + 0.18 cos [15 (t-0.23)]. The presence of a 24 h rhythm of rectal t degree in lambs kept under nycthemeral conditions, and its persistence in lambs kept under constant light suggests that the rhythm of rectal temperature observed in the newborn lamb is a true circadian rhythm.(ABSTRACT TRUNCATED AT 400 WORDS)

Urinary excretion of activatable kallikrein in one-kidney pole-ligated hypertensive rats

Kallikrein activatable by trypsin was found in the urine of normal rats, corresponding to about 33% of the total kallikrein excretion. This fraction was inhibited by aprotinin and kallikrein antiserum. There was no spontaneous activation at 20 degrees C for 24 h or at 37 degrees C for 15 h which indicates that the amount detectable in the urine may represent the levels of activatable kallikrein in the renal tubule. Sephacryl S-200 chromatography of the urine disclosed the presence of two forms of kallikrein, active and activatable, with apparent molecular weights of 30 000 and 34 500 respectively. These findings allow us to assume that the activatable fraction would correspond to prokallikrein, as described by others. In hypertensive one-kidney pole-ligated rats, the total urinary kallikrein did not differ from that excreted by solely uninephrectomized rats, though the active kallikrein showed a significant drop (P less than 0.001). These results suggest that in hypertensive rats there is an alteration in the activation mechanisms of kallikrein.