Neonatal exposure to oestradiol increases dopaminergic transmission in nucleus accumbens and morphine-induced conditioned place preference in adult female rats

Steroid sex hormones produce physiological effects in reproductive tissues and also in nonreproductive tissues, such as the brain, particularly in cortical, limbic and midbrain areas. Dopamine (DA) neurones involved in processes such as prolactin secretion (tuberoinfundibular system), motor circuit regulation (nigrostriatal system) and driving of motivated behaviour (mesocorticolimbic system) are specially regulated by sex hormones. Indeed, sex hormones promote neurochemical and behavioural effects induced by drugs of abuse by tuning midbrain DA neurones in adult animals. However, the long-term effects induced by neonatal exposure to sex hormones on dopaminergic neurotransmission have not been fully studied. The present study aimed to determine whether a single neonatal exposure with oestradiol valerate (EV) results in a programming of dopaminergic neurotransmission in the nucleus accumbens (NAcc) of adult female rats. To answer this question, electrophysiological, neurochemical, cellular, molecular and behavioural techniques were used. The data show that frequency but not amplitude of the spontaneous excitatory postsynaptic current is significantly increased in NAcc medium spiny neurones of EV-treated rats. In addition, DA content and release are both increased in the NAcc of EV-treated rats, caused by an increased synthesis of this neurotransmitter. These results are functionally associated with a higher percentage of EV-treated rats conditioned to morphine, a drug of abuse, compared to controls. In conclusion, neonatal programming with oestradiol increases NAcc dopaminergic neurotransmission in adulthood, which may be associated with increased reinforcing effects of drugs of abuse.

Diagnosis of HIV-Associated Oral Lesions in Relation to Early versus Delayed Antiretroviral Therapy: Results from the CIPRA HT001 Trial

Oral mucosal lesions that are associated with HIV infection can play an important role in guiding the decision to initiate antiretroviral therapy (ART). The incidence of these lesions relative to the timing of ART initiation has not been well characterized. A randomized controlled clinical trial was conducted at the GHESKIO Center in Port-au-Prince, Haiti between 2004 and 2009. 816 HIV-infected ART-naïve participants with CD4 T cell counts between 200 and 350 cells/mm³ were randomized to either immediate ART initiation (early group; N = 408), or initiation when CD4 T cell count was less than or equal 200 cells/mm³ or with the development of an AIDS-defining condition (delayed group; N = 408). Every 3 months, all participants underwent an oral examination. The incidence of oral lesions was 4.10 in the early group and 17.85 in the delayed group (p-value <0.01). In comparison to the early group, there was a significantly higher incidence of candidiasis, hairy leukoplakia, herpes labialis, and recurrent herpes simplex in the delayed group. The incidence of oral warts in delayed group was 0.97 before therapy and 4.27 post-ART initiation (p-value <0.01). In the delayed group the incidence of oral warts post-ART initiation was significantly higher than that seen in the early group (4.27 versus 1.09; p-value <0.01). The incidence of oral warts increased after ART was initiated, and relative to the early group there was a four-fold increase in oral warts if ART was initiated following an AIDS diagnosis. Based upon our findings, candidiasis, hairy leukoplakia, herpes labialis, and recurrent herpes simplex indicate immune suppression and the need to start ART. In contrast, oral warts are a sign of immune reconstitution following ART initiation.

PstS-1, the 38-kDa Mycobacterium tuberculosis glycoprotein, is an adhesin, which binds the macrophage mannose receptor and promotes phagocytosis

Mycobacterium tuberculosis, the primary causative agent of tuberculosis, infects macrophages and transforms the hostile intracellular environment into a permissive niche. M. tuberculosis infects macrophages using a variety of microbial ligand/cell receptor systems. In this study, binding assays with biotin-labelled mycobacterial cell wall proteins revealed five Concanavalin A-reactive proteins that bind macrophages. Among these proteins, we identified PstS-1, a 38-kDa M. tuberculosis mannosylated glycolipoprotein, and characterized it as an adhesin. Inhibition assays with mannan and immunoprecipitation demonstrated that PstS-1 binds the mannose receptor. We purified PstS-1 to 95.9% purity using ion exchange chromatography. The presence of mannose in purified PstS-1 was demonstrated by Concanavalin A interaction, which was abolished in the presence of sodium m-periodate and α-D-mannosidase. Gas chromatography revealed that purified PstS-1 contained 1% of carbohydrates by weight, which was mainly mannose. Finally, we used fluorescent microbeads coated with purified PstS-1 in phagocytosis assays and discovered that microbead uptake was inhibited by the pre-incubation of cells with GlcNAc, mannan and α-methyl mannoside. The interaction of PstS-1 coated beads with the mannose receptor was confirmed by confocal colocalization studies that showed high Pearson and Manders's colocalization coefficients. Our findings contribute to a better understanding of the strategies M. tuberculosis uses to infect host cells, the critical first step in the pathogenesis of tuberculosis.

Neonatal exposure to estradiol valerate increases dopamine content in nigrostriatal pathway during adulthood in the rat

Research in programming has focused in the study of stimuli that affect sensitive periods of development such as prenatal and neonatal stage. We previously showed that exposure to estradiol valerate to female rats during the first 12 h of life increased catecholamine content in ventromedial-arcuatus hypothalamus of the adult rat. However, changes in others dopaminergic circuits have not been studied. The purpose of this work was to determine the neurotransmitters changes induced by neonatal estradiol valerate (0.1 mg/50 μl s. c. per rat) administration on nigrostriatal pathway of adult female rats. Sesame oil (50 μl s. c. per rat) was administered in a control parallel group. EV-1 adult rats presented effective markers of long-term estrogenization as decreased serum levels of progesterone and a reduction in the size of estrogen-sensitive organs. In the brain, neonatal estradiol valerate administration led to a significant increase in dopamine content in striatum, substantia nigra and ventral tegmental area. With respect to the contents of dopamine metabolites, only 3-methoxytyramine content increased in substantia nigra and ventral tegmental area. In addition, the content of noradrenaline increased only in striatum. Interestingly, estrogenized rats lacked locomotor activity induced by acute dose of amphetamine (1 mg/kg i. p.). Altogether, these results show that neonatal exposure to estradiol valerate permanently modified the content of monoamine neurotransmitters in nigrostriatal pathway and amphetamine-induced locomotor activity of adult female rats. This might imply that estrogenized rats could have changes in the expression of key proteins in dopaminergic regulation, as tyrosine hydroxylase and dopamine transporter.

Outbreak of cutaneous leishmaniasis in Fuenlabrada, Madrid

BACKGROUND

Leishmaniasis, an endemic infection in Spain, is caused by protozoan parasites of the Leishmania genus. Between 2010 and 2012, there was an outbreak of cutaneous and visceral leishmaniasis in Fuenlabrada, Madrid.

OBJECTIVES

To describe the cases of cutaneous leishmaniasis diagnosed over a 17-month period at the dermatology department of Hospital de Fuenlabrada.

MATERIAL AND METHODS

We analyzed the epidemiological, clinical, histological, and microbiological features of each case and also evaluated the treatments administered and outcomes.

RESULTS

We studied 149 cases. The incidence of cutaneous leishmaniasis showed a peak in the age range between 46 and 60 years and was similar in men and women. At the time of consultation, the lesions had been present for between 2 and 6 months in the majority of patients. The most common clinical presentation was with erythematous plaques and papules without crusts (52% of cases). Lesions were most often located in sun-exposed areas and were multiple in 57% of patients. In 67% of cases, the histological study showed non-necrotizing granulomatous dermatitis with no evidence of parasites using conventional staining methods. Diagnosis was confirmed by polymerase chain reaction (PCR) in 98% of patients. In the remaining cases, the histological study revealed Leishman-Donovan bodies in the skin. Intralesional pentavalent antimonials were the most commonly used drugs (76% of cases) and produced satisfactory results.

CONCLUSIONS

We have presented a large series of cases of cutaneous leishmaniasis diagnosed in the context of an outbreak. Multiple papules were the most common clinical presentation, with histology that showed non-necrotizing granulomatous dermatitis with no evidence of parasites. PCR of skin samples was the test that most frequently provided the diagnosis.

Mycobacterium tuberculosis 38-kDa lipoprotein is apoptogenic for human monocyte-derived macrophages

Mycobacterium tuberculosis is the main aetiologic agent of tuberculosis, a disease of great concern in less-developed regions. Apoptosis is a conspicuous event in macrophages infected in vitro with mycobacteria, a phenomenon also observed in vivo in granulomas of patients with tuberculosis. To determine its significance, it is important to define the mycobacterial moieties involved and how they cause apoptosis. Here we show that the 38-kDa lipoprotein induces macrophage caspase-dependent apoptosis involving TNF-alpha and FasL and, interestingly, with the upregulation of cell-death receptors TNFR1, TNFR2 and Fas. A role for the Toll-like receptor 2 was also demonstrated. In conclusion, the ability to induce apoptosis of host cells is another property of the 38-kDa lipoprotein, a molecule that has focused attention for being an immunodominant antigen that participates in phosphate transport.

Analysis of competing risks of causes of death and their variation over different time periods in Hodgkin disease

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Background: Hodgkin’s disease is put forward as a model of curable illness. However, long-term studies show an excessive mortality in relation to the general population. The only way for detecting these causes are the long-term follow-up clinical studies, even these long-term follow-ups may not be fully representative of current causes of death. Methods: All patients diagnosed with HD at the University Hospital “Clínica Puerta de Hierro” between 1967 and 2003 were included. The competing risks of causes of death and the vital situation were examined in three time periods. Three cohorts were compared: cohort A with patients treated before 1980, B with those treated 1981–1986 and C from 1986 on. Results: We studied 534 patients, with a median follow-up time of 9.1 years for the whole cohort. The 5, 15 and 20-year Kaplan-Meier survival estimates for all patients were 81%, 72% and 65%, respectively. At the close of the study, 337 (63.1%) were alive and 170 (31.8%) had died. In general, the most common cause was the progress of Hodgkin’s disease, followed by deaths due to a second tumor. By time periods, we found statistically significant differences between cohort A and the other two cohorts, with less LD and MC histology, fewer advanced stages and fewer combined treatments in the latter. Between cohorts B and C there were only differences in the histological results, with less LD and MC and increased NS in the latter. Survival was significantly worse in the first period than in the other two (p<0.001) and in the three periods the main cause of death was tumor progression. Conclusions: The progression of Hodgkin’s disease is the main cause of death in all the periods studied. Over time a clear reduction in death related to the toxicity of treatments was seen. In the light of our results, the question is posed as to whether the survival and causes of death series for those patients treated since the 1970s are telling us about a real situation. Patients die now for reasons that are different from in the 1970s and this is important when planning preventive and clinical research activity.

No significant financial relationships to disclose.

The impact of a clinical training unit on integrated child health care in Mexico

This study had two aims: to describe the activities of a clinical training unit set up for the integrated management of sick children, and to evaluate the impact of the unit after its first four years of operation. The training unit was set up in the outpatient ward of a government hospital and was staffed by a paediatrician, a family medicine physician, two nurses and a nutritionist. The staff kept a computerized database for all patients seen and they were supervised once a month. During the first three years, the demand for first-time medical consultation increased by 477% for acute respiratory infections (ARI) and 134% for acute diarrhoea (AD), with an average annual increase of demand for medical care of 125%. Eighty-nine per cent of mothers who took their child for consultation and 85% of mothers who lived in the catchment area and had a deceased child received training on how to recognize alarming signs in a sick child. Fifty-eight per cent of these mothers were evaluated as being properly trained. Eighty-five per cent of primary care physicians who worked for government institutions (n = 350) and 45% of private physicians (n = 90) were also trained in the recognition and proper management of AD and ARI. ARI mortality in children under 1 year of age in the catchment area (which included about 25,000 children under 5 years of age) decreased by 43.2% in three years, while mortality in children under 5 years of age decreased by 38.8%. The corresponding figures for AD mortality reduction were 36.3% and 33.6%. In this same period, 11 clinical research protocols were written. In summary, we learned that a clinical training unit for integrated child care management was an excellent way to offer in-service training for primary health care physicians.

Multicompartment urea kinetics in well-dialyzed children

BACKGROUND

We have reported catch-up growth with hemodialysis (HD) of approximately 15 hours/week. Without an equilibrated post-treatment blood urea nitrogen, the variable-volume single-pool (VVSP) model will not account for urea rebound, inflating the estimated HD dose (K(d)t/V). A two-pool model (FVDP) predicts rebound, but requires fixed compartment volumes for the equations to be solvable in closed form, also inflating K(d)t/V.

METHODS

We developed an approximate perturbation solution (WKB method) to a variable volume, two-pool (VVDP) model. Estimated model parameters were compared with the results of equilibrated kinetic studies using measured clearance K(d) (N = 17). Once the model was validated, we re-analyzed 292 kinetic studies from our earlier cohort, which was considered well-dialyzed on the basis of growth rates (N = 12, mean annual change in height standard deviation score +0.31, mean follow-up of 26 months).

RESULTS

For the VVSP, FVDP, and VVDP models, respectively, the mean errors were (1) K(d)t/V, 0.22 +/- 0.07, 0.29 +/- 0.17, 0.06 +/- 0.07 (ANOVA, P < 0.001); (2) urea distribution volume vol/wt (%), -8.2 +/- 4.2, -9.1 +/- 3.0, -2.2 +/- 3.6 (P < 0.001). Sequential studies confirmed reproducibility, with a coefficient of variation < or = 5%. In the earlier cohort, a comparison of the VVSP and VVDP models yielded the following: (1) K(d)t/V, 1.91 +/- 0.35 vs. 1.76 +/- 0.33 (P < 0.001); (2) normalized protein catabolic rate (nPCR, g/kg/day), 1.56 +/- 0.39 vs. 1.52 +/- 0.38 (P < 0.001); and (3) K(d) (whole blood, mL/kg/min), 4.8 +/- 0.9 vs. 4.4 +/- 0.8 (P < 0.001).

CONCLUSION

This VVDP model yields reliable estimates of K(d)t/V and other kinetic parameters using standard blood urea nitrogen sampling. Analysis of patients previously characterized as well-dialyzed on the basis of growth rates clarifies the HD dose needed to sustain normal growth.

Epilepsy and neurocysticercosis in an Andean community

BACKGROUND

Taenia solium neurocysticercosis (NCC) has been documented as one of the major causes of epilepsy in developing countries. However, methodological limitations have hindered the evaluation of the epidemiological relationship between cysticercosis and epilepsy at the community level.

METHODS

We used the WHO protocol for epidemiological evaluation of neurological disorders to conduct a door-to-door survey among 2723 residents of San Pablo del Lago, an Ecuadorean rural community in which T. solium taeniasis/cysticercosis was known to be endemic. The WHO protocol was complemented by neuroimaging and immunological tests to confirm the diagnosis of this infection.

RESULTS

In all 31 people suffering from active epilepsy were detected (prevalence 11.4 per 1000, 95% CI:7.7-15.4); 26 agreed to undergo a computer tomography (CT) examination, and 28 agreed to have blood drawn for serodiagnosis. Fourteen of the 26 (53.8%) had CT changes compatible with NCC and six of the 28 (21.4%) tested positive in the enzyme-linked immunoelectro-transfer blot (EITB) assay. In a seizure-free random sample of this population, 17 of 118 (144 per 1000) subjects examined by CT and 10 out of 96 (104 per 1000) examined by EITB had evidence of this infection. The differences between the epilepsy group and the random sample of the population were statistically significant (OR = 6.93, 95% CI: 2.7-17.5, P < 0.001) for CT diagnosis, but not for EITB results (OR = 2.75, 95% CI: 0.8-7.1, P > 0.12, NS).

CONCLUSIONS

These findings confirm that T. solium NCC is a significant cause of epilepsy at the community level in Andean villages of Ecuador. It is important to initiate effective public health interventions to eliminate this infection, which may be responsible for at least half of the cases of reported epilepsy in Ecuador.

Growth during maintenance hemodialysis: impact of enhanced nutrition and clearance

Growth of children during maintenance hemodialysis has been reported to be uniformly poor, with a mean annual loss of 0.4 to 0.8 SD in height. We adopted an intensive program of closely monitored energy and protein intake with dialysis urea clearances exceeding conventional recommendations. Twelve prepubertal or early pubertal children (aged 7 months to 14 years) were monitored for an average of 2.2 years (range 4 to 81 months) while receiving maintenance hemodialysis. These children received an average of 90.6% and 155.9% of their recommended energy and protein nutritional intake, respectively. With a prescribed urea clearance of 5 mL/kg/min, we achieved a mean single treatment urea clearance normalized for total body water of 2.00, a urea reduction ratio of 84.7%, and an average time of hemodialysis of 14.8 h/wk, all well beyond current guidelines. Over the course of dialysis treatment, the improvement in height SD score was+0.31 SD/y (+0.32 excluding the 2 children treated with recombinant human growth hormone). Normal growth was achieved without overt obesity and was associated with normal pubertal growth spurt. These findings suggest that the combination of increased dialysis and adequate nutrition can promote normal growth in children treated with long-term hemodialysis.

A clinical training unit for diarrhoea and acute respiratory infections: an intervention for primary health care physicians in Mexico

In Tlaxcala State, Mexico, we determined that 80% of children who died from diarrhoea or acute respiratory infections (ARI) received medical care before death; in more than 70% of the cases this care was provided by a private physician. Several strategies have been developed to improve physicians' primary health care practices but private practitioners have only rarely been included. The objective of the present study was to evaluate the impact of in-service training on the case management of diarrhoea and ARI among under-5-year-olds provided by private and public primary physicians. The training consisted of a five-day course of in-service practice during which physicians diagnosed and treated sick children attending a centre and conducted clinical discussions of cases under guidance. Each training course was limited to six physicians. Clinical performance was evaluated by observation before and after the courses. The evaluation of diarrhoea case management covered assessment of dehydration, hydration therapy, prescription of antimicrobial and other drugs, advice on diet, and counselling for mothers; that of ARI case management covered diagnosis, decisions on antimicrobial therapy, use of symptomatic drugs, and counselling for mothers. In general the performance of public physicians both before and after the intervention was better than that of private doctors. Most aspects of the case management of children with diarrhoea improved among both groups of physicians after the course; the proportion of private physicians who had five or six correct elements out of six increased from 14% to 37%: for public physicians the corresponding increase was from 53% to 73%. In ARI case management, decisions taken on antimicrobial therapy and symptomatic drug use improved in both groups; the proportion of private physicians with at least three correct elements out of four increased from 13% to 42%, while among public doctors the corresponding increase was from 43% to 78%. Hands-on training courses thus seemed to be effective in improving the practice of physicians in both the private and public sectors.

The quality of private and public primary health care management of children with diarrhoea and acute respiratory infections in Tlaxcala, Mexico

In Tlaxcala, Mexico, 80% of the children who died from diarrhoea or acute respiratory infections (ARI) in 1992-1993 received medical care; in more than 70% of cases it was provided by a private general practitioner (GP). The present study evaluated the quality of case management by private and public GPs to children under five years of age with diarrhoea and ARI. During the clinical observation, the treatment and counselling given to the mother were assessed with the WHO guidelines as reference standard. A total of 41 private and 40 public GPs were evaluated for the management of diarrhoea, and 59 private and 40 public GPs for the management of ARI. For diarrhoea, half of the private GPs gave inadequate rehydration therapy, 63% gave incorrect advice on diet, 66% and 49% made an incorrect correct decision in the prescription of antimicrobial and symptomatic drugs, respectively. Public GPs generally performed better in diarrhoea management: 7% gave inadequate rehydration therapy, 13% gave wrong advice on diet, 3% made a wrong decision in the prescription of symptomatic drugs and 28% gave a wrong decision in antimicrobial prescription. In the management of ARI, 66% and 58% of private GPs made a wrong decision in the prescription of antimicrobial and symptomatic drugs, respectively, compared to 30% and 20% of public GPs, respectively. Counselling to the mother given by both private and public GPs was considered inadequate in most cases of diarrhoea and ARI. These results clearly show that private doctors, as important providers of medical care, need to be included in the strategies to improve the quality of care of children with diarrhoea and ARI. Future research needs to address the determinants of the clinical practice of private doctors in countries like Mexico.

Determination of tin in canned fruits and vegetables by atomic absorption spectrometry and liquid-liquid extraction

A method was developed for the determination of tin based on the extraction of its 5,5'-methylenedisalicylohydroxamic acid complex with 1.09M isobutyl methyl ketone in tributyl phosphate. After the samples were treated with nitric and hydrochloric acid, the aqueous phase was made to 0.05M in perchloric acid. When the ratio of aqueous phase to organic phase was 4:1 (v/v), the detection limit and the relative standard deviation (n = 7, 50 micrograms tin) were 0.20 microgram/mL and 0.9%, respectively. The proposed method was applied to the analysis of tin in canned fruits and vegetables. The results were in good agreement with those obtained by the phenylfluorone method.

[Critical reading in selected groups of medical students]

BACKGROUND

The shaping of professionals with a critical outlook in their field of endeavor is a goal of some educational institutions in our country. However, little participation from the students is demanded in our medical schools and this probably interferes in the development of skills for critical reading.

OBJECTIVE

To evaluate critical reading in medical students with high scholastic achievement as a function of years of medical training.

MATERIAL AND METHODS

We studied three groups of medical students who were homogeneous in regard to scholastic achievement (their mean was 9 or higher in a scale of 10). The groups were in the first, third and fifth year of their medical training (N was 24, 15 and 12 respectively). Two homogeneous groups of low achievers (mean of 7 or less in their first year of training with N of 20 and 16) were also included as contrast groups (no homogeneous groups of low achievers were present in higher years). The test applied was elaborated by us and has been validated. It evaluates reading comprehension (30 items) and interpretation (40 items) of medical information with questions to be answered true/false/don't know and which are scored -1 (incorrect), zero (don't know) or 1 (correct). The scores were analyzed using non-parametric techniques. We consider reading interpretation as a capacity better representing critical reading.

RESULTS

In the three groups of high achievers, comprehension was the same (median of 26 out of a maximum of 30) and interpretation ranged from 21.5 to 23 with no group differences (Kruskal-Wallis test). The high achievers had significantly higher scores in reading and interpretation than the low achievers (U test p < 0.01). There was also a consistent higher score of comprehension over interpretation in the five groups (chi square of proportions p < 0.01) but the association of comprehension and interpretation was present only in three groups (high achievers in 1st and 3d year and low in 1st with correlations of Spearman ranging from 0.43 to 0.56).

CONCLUSIONS

We were unable to detect any significant difference of years of medical training in the ability to comprehend or interpret medical information. We were able to detect differences in these abilities between high and low achievers.

[Isolation of Mycobacterium tuberculosis with primary resistance to chemotherapeutic agents in patients with HIV infection]

BACKGROUND

To evaluate the resistance of Mycobacterium tuberculosis in subjects with simultaneous infection by the human immunodeficiency virus.

METHODS

Isolation of Mycobacterium tuberculosis was carried out in a University hospital over a period of 7 years with selection of those corresponding to subjects with HIV infection. The isolation of Mycobacterium tuberculosis with resistance to one or more chemotherapeutic drugs was identified and is described herein.

RESULTS

A total of 287 subjects were identified having tuberculous disease, 39 (13.59%) of them presented a simultaneous infection by the human immunodeficiency virus. In 4 of the latter (10.26%) Mycobacterium tuberculosis resistant to one or more chemotherapeutic drugs was isolated with the most frequent resistance being to isoniazide (3/4).

CONCLUSIONS

A high degree of diagnostic suspicion must be maintained in patients with the human immunodeficiency virus with respect to tuberculosis, not only because of frequent endogenous activation but also because of the danger of in-hospital transmission. The possibility of resistance makes systematic antibiograms in these cases advisable. In these patients recommendations regarding treatment should be followed avoiding shortened or simplified therapeutic periods which have occasionally been demonstrated as ineffective.

Enterotoxigenic and necrotizing Escherichia coli in human diarrhoea in Spain

Enterotoxigenic Escherichia coli (ETEC) strains of serotype 0153: K-:H45 CFA/I+ STa+ were associated with two outbreaks of neonatal diarrhoea that occurred in two different hospitals of Madrid, in one of which several children died. Two other outbreaks were associated with ETEC strains of serotypes 0159: K-:H21 (LT+) and 0159: K-:H4 (LT+ STa+) without CFA/I and CFA/II colonization factors. Necrotizing E. coli (NTEC) strains of serotype 06:K13, producing the cytotoxic necrotizing factor CNF1 and alpha-haemolysin, were also associated with two outbreaks of neonatal diarrhoea that occurred in a hospital in Madrid and in a hospital in Talavera de la Reina. The results of the characterization of some ETEC and NTEC strains isolated from sporadic cases of diarrhoea are also discussed.

Attempts to establish phage typing as an epidemiological marker for Salmonella enteritidis

The notable increase in the number of Salmonella enteritidis strains seen in Spain in recent years (from 27.10% in 1980 to 66.36% in 1985) makes it necessary to find an additional epidemiological marker for this serotype. Phage typing was considered because of its discriminatory capacity toward other Salmonella serotypes. Wild and lysogenic bacteriophages were sought for a set of autochthonous bacteriophages. Our set consisted of 6 bacteriophages, 5 wild and 1 lysogenic. When tested on 1,500 selected strains, they produced 9 different phage types. The most abundant phage types were A (74.66%) and B (19.73%). The percentage of non-typable strains was low: only 1.4% from a total of 1,500 strains failed to produce lysis with our set. This reflects the high typability of the bacteriophage set proposed.

Field evaluation of enzyme-linked immunosorbent assay for the serodiagnosis of tuberculosis

An enzyme-linked immunosorbent assay (ELISA) was evaluated as a serodiagnostic test for active tuberculosis in La Paz, Bolivia. ELISA was compared with sputum smear in 277 persons presenting to the Instituto de Torax and was used for screening in 1,458 military personnel. The test was performed under field conditions on 4-microliter samples of capillary blood obtained by finger prick. ELISA was found to have a sensitivity of 69% and a specificity of 88%. Sputum smear had a sensitivity of 79% and a specificity of 100%. ELISA was found to have undiminished sensitivity and specificity in patients who were sputum-negative, and the two tests could be combined to achieve a sensitivity of 92% and specificity of 88%. Positive and negative predictive values were highest for populations with tuberculosis prevalences in the range of that seen among patients presenting to the Instituto de Torax in Bolivia, but ELISA also led to the diagnosis of tuberculosis in 5 of 1,458 soldiers tested in the screening program.