Comparison of exhaled nitric oxide measurements between NIOX MINO electrochemical and Ecomedics chemiluminescence analyzer

BACKGROUND

Exhaled nitric oxide (eNO) is an established, noninvasive biomarker of active airway inflammation in (atopic) asthma. Treatment with anti-inflammatory therapy, such as inhaled corticosteroids, effectively decreases eNO levels. The NIOX MINO (MINO) is a hand-held, relatively inexpensive, electrochemical device that has been shown to yield comparable eNO measurements to the NIOX stationary unit.

AIM

To compare measurements of MINO with another widely used and validated stationary chemiluminescence analyzer, the Ecomedics (ECO).

METHODS

We performed subsequent eNO measurements on ECO and MINO in 50 subjects (19 healthy volunteers, 18 healthy smokers and 13 non-smoking, atopic asthmatics, not on controller therapy) on two visits 4-10 days apart. The mean of three acceptable measurements by ECO and the first acceptable measurement with the MINO were used for analysis.

RESULTS

Both devices yielded reproducible eNO values for all subjects on both visits, with an overall CV of 22.7% (ECO) and 18.3% (MINO). A significant correlation was found between both devices (r=0.97, p<0.0001). Bland-Altman plots showed a high degree of agreement for the entire study population (mean difference MINO vs ECO=-10%; 95% limit of agreement were -36% and +28%) and in the three individual subgroups.

CONCLUSIONS

Exhaled NO values measured with the MINO are reproducible and in agreement with the ECO. Our results add further evidence to the reliability of the MINO and warrant its applicability in research and clinical practice.

Smoking in Colombian medical schools: the hidden curriculum

BACKGROUND

Tobacco companies are focusing their interest in less developed countries. In the absence of governmental opposition, physicians are expected to lead tobacco control efforts. We studied Colombian medical students' smoking prevalence and tobacco attitudes.

METHODS

First- and fifth-year students from 11 medical schools in seven Colombian cities answered anonymous, self-administered, 38-item questionnaires. Additionally, smokers answered the Fagerström Test for Nicotine Dependence (FTND).

RESULTS

Two thousand twenty-one students (males 50.6%; age 15-44, median 19) completed the survey; average response rate was 89.9%. Globally 25.9% of students were current smokers (males 27.9%, females 24.0%). Living at higher altitude and attending private universities were associated with higher prevalence (P < 0.001). Males had a higher chance of having given up smoking (P < 0.05); 91.3% of current smokers would like to quit; 67.3% of all smokers and 44.8% of daily smokers scored 0 in the FTND. Prevalence was similar among first- and fifth-years, but fifth-year students were more complacent with smoking in health centers and showed a lesser desire to quit.

CONCLUSIONS

Medical students' smoking prevalence is similar to that of the general population. Tobacco control strategies need to be included in the curriculum. Nicotine addiction does not seem to be the main perpetuating factor.

Zidovudine therapy protects against Salmonella bacteremia recurrence in human immunodeficiency virus-infected patients

Fifty-five human immunodeficiency virus-infected patients with Salmonella bacteremia were studied to assess the rate of and causes for recurrence and to determine the influence on relapse of zidovudine, cotrimoxazole, and antimicrobial suppressive therapy according to the susceptibility of the isolates. Overall, 22% of patients relapsed in a median time of 87 days, independent of CD4 cell count, Salmonella serotype, or duration of antibiotic therapy. The use of zidovudine was associated with the lowest rate of recurrences compared with cotrimoxazole or amoxicillin as suppressive therapy. In the microbiologic assay, zidovudine showed bactericidal effect on Salmonella species at current dosages, and resistance to zidovudine was uncommon (2 cases, 4%). Due to its direct effect on Salmonella species, a zidovudine-containing regimen may protect against the recurrence of the disease.

Technetium-99m-MAG3 in early identification of pyelonephritis in children

The purpose of this study was to determine whether 99mTc-mercaptotriacetylglycine (MAG3) can substitute for 99mTc-glucoheptonate (GH) in the detection of pyelonephritis.

METHODS

One hundred thirty renal scintigraphies were evaluated retrospectively in 38 children (21% boys, 79% girls; age range 1 mo-21 yr; mean age 7.2 yr) referred for evaluation during an acute clinical urinary tract infection and for follow-up studies. Twelve topographical regions were designated on each kidney. Each area was graded for severity of decreased radionuclide localization: mild (Grade 1), moderate (Grade 2) or marked (Grade 3). Early posterior views of MAG3 studies were compared to delayed posterior GH images. In all patients, both studies were performed on the same day.

RESULTS

Eighty-two studies were performed during an acute clinical infection and 48 were performed as follow-up. Seventy-seven percent of the studies had focal cortical lesions. Of all the cortical lesions identified by GH, MAG3 detected 74% (match lesions). A comparable percentage of lesions was identified in each region by both studies. GH scintigraphy detected 261 lesions (63 Grade 1, 149 Grade 2 and 49 Grade 3), and MAG3 detected 201 lesions (37 Grade 1, 117 Grade 2 and 47 Grade 3). MAG3 was unable to recognize 60 lesions identified by GH studies in 11 patients (mismatch lesions). Of these, 41% (26 of 63) were Grade 1, 21% (32 of 149) were Grade 2 and 4% (2 of 49) were Grade 3. In three cases, MAG3 identified lesions not seen by GH (reverse mismatch); all had acute symptomatic infection.

CONCLUSION

These data document that MAG3 in the early phase of the study (1-2 min) can detect Grade 2 to Grade 3 cortical lesions in patients with pyelonephritis, but it is less effective in detecting Grade 1 lesions.

An epidemic of collective conversion and dissociation disorder in an indigenous group of Colombia: its relation to cultural change

We describe a collective episode of psychogenic illness in an indigenous group (Embera) of Colombia, geographically isolated from its native homeland and surrounded by non-indigenous settlers. The condition, which affected three young adult men and six adolescent women, was attributed by them to a spell (maleficio). It was designated as ataques de locura (madness attacks) according to their traditional medical system; and as a conversive disorder with dissociative features by psychiatrists. Different therapeutic approaches, including antipsychotic medication, religious healers and traditional herbal remedies were unsuccessful. Contact with shamans of the same ethnic origin, on the other hand, proved to be an effective way of dealing with the symptoms. We interpret the situation as an expression of psychosocial stress secondary to cultural change. This medical problem bears close resemblance to other specific culture-bound syndromes such as ataques de nervios or possession syndromes and gives clues to ways of dealing with psychogenic expressions of cultural stress.

Exposure of Puerto Rican children to environmental tobacco smoke

BACKGROUND

Many studies of environmental tobacco smoke (ETS) have been conducted in northern, industrialized countries. As yet, however, no studies have been carried out on ETS exposure with nonsmokers living in tropical environments.

METHODS

Urine specimens were collected from 175 healthy Puerto Rican children (2-11 years) living in an industrial area and were analyzed for cotinine, a quantitative biomarker for exposure to ETS. Their parents completed a questionnaire covering smoking habits.

RESULTS

Seventy percent of children were exposed to ETS. Quantitatively, exposure to smoke in households consuming more than 1 pack per day (ppd) caused a doubling of cotinine excretion compared with households consuming less than 1 ppd. Smoke from mothers made the greatest contribution to cotinine, followed by smoke from fathers, with smoke from other persons having no effect. Degree of exposure was inversely related to age of the child.

CONCLUSIONS

Young children (2-4 years) were detected to have significantly greater exposure to ETS than older children (5-11 years) and in the younger group the effect seemed to be from the mother's smoking much more than the father's, with other persons contributing negligible amounts. This suggests an obvious strategy for prevention of exposure to ETS in young children.

Changes in the quality of life of patients with end-stage renal disease treated with high-efficiency bicarbonate hemodialysis in Mexico

In accordance with the epidemiological changes in Mexico, the results of this study are intended to contribute to the evaluation of the end-stage renal disease (ESRD) program of the health services in Mexico. We measured the quality of life of 21 ESRD patients before and after 6 months of exposure to treatment with high-efficiency hemodialysis with bicarbonate (HEHD/bicarbonate). We cross-sectionally assessed the Quality Adjusted Life Year (QALY) index and the biochemical status of the subject pool. The QALY score for patients undergoing HEHD/bicarbonate after 6 months was significantly higher than with the previous dialysis modality (0.95 and 0.74, respectively, p = 0.02). The marked similarities of the biochemical status variables indicated there was little or no effect in the improvement of the quality of life of patients. Dialysis modality likely exerts an important influence on the quality of life of chronic dialysis patients; thus we believe HEHD/bicarbonate does offer greater benefits than hemodialysis alone. Longitudinal studies are needed to better ascertain the effect of the case mix, the treatment approach, and the characteristics of the dialysis in relation to the improvement of the quality of life of ESRD patients.

The routine use of Rh-negative reagent red cells for the identification of anti-D and the detection of non-D red cell antibodies

BACKGROUND

Before 1987, fewer than 50 patients per year at the authors' laboratory had a positive antibody detection test due to antepartum Rhesus immunoprophylaxis. However, after 1987, a marked increase was observed in the number of patients who had received Rh immune globulin (RhIG) during pregnancy as part of routine antepartum Rh immunoprophylaxis. In anticipation that an increased use of RhIG during pregnancy would increase the number of patients in whom anti-D was detected by this laboratory, a protocol was developed to abbreviate the process required to identify anti-D. Although this protocol was adopted primarily to address an anticipated increase in antenatal RhIG usage in women, it was also applied to alloimmunized Rh-negative males.

STUDY DESIGN AND METHODS

When an Rh-negative patient (male or female) had a reactive screening test for unexpected antibodies and met certain other criteria, the patient's serum was tested with a three-vial set of Rh-negative reagent red cells (Rh-negative screening RBCs), instead of with panels of typed RBCs (panel RBCs), for the identification of anti-D or the detection of non-D antibodies. If the serum under test did not agglutinate or hemolyze Rh-negative screening RBCs, anti-D was identified and no further testing was performed. If the serum agglutinated or hemolyzed Rh-negative screening RBCs, conventional testing with panel RBCs was done to determine the antibody specificity.

RESULTS

Rh-negative patients (n = 1174) who had reactive screening tests for unexpected antibodies were tested with Rh-negative screening RBCs; 1079 were found to have anti-D as a single antibody. Seven of these patients subsequently developed a non-D alloantibody, after transfusion or pregnancy, and one patient had anti-C that escaped detection at the time of initial testing with Rh-negative RBCs (a false-negative result). Ninety-two patients had anti-D in combination with a non-D antibody, and three patients had a non-D antibody but not anti-D. Use of the anti-D identification protocol actually reduced the laboratory workload by 176 College of American Pathologists workload units per month, in spite of a marked increase in the number of patients in whom anti-D was detected. No hemolytic transfusion reaction was attributed to the abbreviation of anti-D identification.

CONCLUSION

The identification of anti-D may be abbreviated without jeopardizing patient safety. Such a protocol can reduce laboratory workload and might be particularly appealing to health care facilities that perform antibody detection testing on large numbers of Rh-negative pregnant women, especially if antepartum RhIG is administered routinely.

Diagnostic exposure in a primary care clinic during pediatric training

A retrospective and descriptive study was done in a general pediatric training site with the purpose of identifying the diagnoses to which the trainees have been exposed, as well as the changes in the pattern of these diagnoses. The number of patient-doctor contacts, type of patient visit, and frequency of diagnoses were compared. A total of 66,054 patient-doctor contacts occurred during the years 1979 to 1989, comprising 79.6 percent scheduled health visits and 20.4 percent emergency visits. The main diagnoses were: healthy child/adolescent (HV), well baby (WB), upper respiratory infection, skin diseases, bronchial asthma, acute gastroenteritis, otitis media, anemia, incomplete immunization, psychosocial problems, nutritional/linear growth problems, psychosomatic disturbances, parasitosis, and pneumonia. There was a significant decrease (P < .005) in the diagnosis of infectious diseases and a significant increase (P < .005) in the proportion of WB and HV. The latter were the two most common diagnoses in the year 1989.

The sensitivity of antibody detection testing using pooled versus unpooled reagent red cells

Because the sensitivity of antibody detection testing may be reduced when pooled reagent red blood cells (RBCs) are used, the American Association of Blood Banks (AABB) prohibits the use of pooled reagent RBCs when performing pretransfusion antibody detection testing. This restriction imposed upon the use of pooled reagent RBCs is based, at least in part, on the belief that pooled reagent RBCs are less likely to detect clinically significant antibodies than are sets of unpooled reagent RBCs. Little data, however, have been published to support this contention. In the present study, the data show a decreased sensitivity for antibody detection when pooled reagent RBCs are used. This reduced sensitivity could result in failure to detect some clinically significant RBC alloantibodies, which might result in the occurrence of overt hemolytic transfusion reactions, especially if an indirect antiglobulin test is not performed at the time blood is crossmatched.

Nisin Sensitivity of Lactic Acid Bacteria Isolated from Cured and Fermented Meat Products

Thirty strains of lactic acid bacteria from different meat sources (bologna, summer sausage, thurlinger sausage, chicken loaf and bacon) were tested for nisin sensitivity. The maximum concentration of nisin permitting growth for 20 strains was 50 IU/ml. Lactobacilli classified as atypical were sensitive to <5 IU nisin/ml. These strains could not be induced to increase resistance by five transfers to media with increased nisin concentrations. The ten strains with the higher resistance to nisin were checked for nisinase activity. One strain, Lactobacillus brevis , showed weak nisinase activity and the rest were negative.

Shelf-Life Studies of Vacuum-Packaged Bacon Treated with Nisin

The effect of various concentrations of nisin (250, 500 or 750 IU/g) combined with 50 ppm sodium nitrite on the shelf-life of vacuum-packaged bacon was evaluated. Control packages of bacon containing 50 and 150 ppm nitrite were included. Total numbers of lactic acid bacteria (LAB) (as measured on MRS medium) was used as a criterion for shelf-life. Treated bacon samples were stored at 30 and 5°C for 4 d or 6 wk, respectively. Bacon stored at 30°C showed a 1-d extension of shelf-life at nisin levels of 500 and 750 IU/g. Lowest counts at 6 wk were in bacon treated with 750 IU nisin and stored at 5°C. The LAB count was 1.5-log₁₀ CFU/g lower than the controls. A 1-wk extension of storage life was predicted for nisin-treated (750 IU) bacon.

Vertebral hydatid disease. Clinical experience with 27 cases

The authors present 27 cases of vertebral hydatidosis with clinical and laboratory findings. The most frequent location of the lesion was the lumbar spine. Principal neurological symptoms were paraparesis, sphincter disturbances, paresthesia and paraplegia. The average number of surgical interventions per patient was 2.6; the most common procedure was laminectomy with extirpation of the cyst and surgical toilet. The results of surgical treatment were generally good in the immediate postoperative period, but long-term results were poor.