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PubMed1998

Tuberculous lesions of the lumbosacral region. A 15-year follow-up of patients treated by ambulant chemotherapy.

STUDY DESIGN: A 15-year clinical follow-up of tuberculous lesions of the lumbosacral region. OBJECTIVES: To verify the hypothesis that the lumbar lordosis and the specific biomechanics of the lumbosacral region influence and alter the healing pattern and progress of the disease when compared with their effects in other regions of the spine. SUMMARY OF BACKGROUND DATA: An estimated 2 million or more patients have active spinal tuberculosis, and the global incidence of the disease is increasing. The involvement of the lower lumbar region and the lumbosacral junction is relatively rare, with few reports in English literature. METHODS: Of a total of 304 patients forming a part of a controlled clinical trial comparing two forms of therapy in spinal tuberculosis, 53 patients had involvement of L3 and below. The following data were studied in these patients: age at start of treatment, number of vertebra involved, vertebral body loss, progress of the angle of kyphosis, and anterior and posterior growth of the involved segment during a period of 15 years. Student's t test for independent samples was used for statistical analysis. RESULTS: The fourth lumbar vertebra was the most common vertebral segment involved, and the lumbosacral junction was affected in 12 patients. The average pretreatment kyphosis was 6.4 degrees and increased to 10.2 degrees at the end of 15 years. The average kyphotio angle per vertebral body loss was 4.9 degrees, far less than in the dorsolumbar region in which kyphotic angles of 27-30 degrees have been reported. Children younger than 10 years old differed in clinical appearance and progress compared with those older than 17 years. They not only showed more extensive involvement but also had more deformity with the same vertebral loss. Twelve patients less than 10 years old had an average involvement of 3.1 vertebral bodies and an average vertebral loss of 2.2 bodies. In comparison, the average number of vertebrae involved was 1.9 (P < 0.01) and the vertebral body loss was only 0.87 (P < 0.01) in patients older than 17 years. Also, the average kyphosis was 6.4 degrees compared with only 4.2 degrees (P < 0.01) in adults. In patients older than 17 years, there was no change after 2 years, by which time the collapse was complete. Four of 12 patients less than 10 years old, showed progressive kyphosis caused by continued growth of posterior parts of the body (i.e., sequestrated hemivertebrae). CONCLUSIONS: In tuberculosis of the lumbosacral region, the development of kyphosis is minimal in patients older than 17 years, when growth has already stopped, and deformity is expressed more as foreshortening of the trunk. Children younger than 10 years old have more severe involvement with increased tendency toward greater kyphosis. They are also prone to progressive deformity through the years when the anterior growth plates are destroyed. Surgery is indicated in this group to prevent greater deformity.

Adolescent↗

PubMed1983

Fifteen year follow-up of lung function in obstructive and non-obstructive pulmonary tuberculosis.

Pulmonary function (VC, FEV1, RV) was assessed in patients with pulmonary tuberculosis discharged in 1958/59 as cured or markedly improved. According to FEV1/VC% the patients were divided into 40 obstructive and 59 non-obstructive cases and the tests were repeated by the same method in 1974. The control included physical and X-ray examinations, a questionnaire and the assessment of airway resistance (Rt). In the non-obstructive group the change in VC in 15 years was only -27.7 ml/year, in the obstructive group, -54.3 ml/year. There was little difference between the two groups in the diminution of FEV1 (28.8 and 35.3 ml/year, respectively). The material was subdivided into surgically and drug treated groups and studied statistically. The only significant change of function in the surgically treated group was in RV, whereas in the other group nearly all of the functional changes were significant statistically.

Adult↗

PubMed2001

Previous pulmonary diseases and risk of lung cancer in Gansu Province, China.

BACKGROUND: Although active smoking is well established as the main cause of lung cancer, there is accumulating evidence that history of prior lung diseases may be an independent risk factor for lung cancer. METHODS: A population-based case-control study in Gansu Province, China identified 886 lung cancer cases (656 male, 230 female) diagnosed between January 1994 and April 1998. A standardized interview collected information on a variety of potential risk factors including a history of physician-diagnosed non-malignant lung diseases (pulmonary tuberculosis, chronic bronchitis/emphysema, asthma, pneumonia), age and year in which each condition was first diagnosed, and any therapy or hospitalization received. RESULTS: Pulmonary tuberculosis (odds ratio [OR] = 2.1, 95% CI : 1.4-3.1) and chronic bronchitis/emphysema (OR = 1.4, 95% CI : 1.1-1.8) were associated with increased risk of lung cancer, after adjustment for active smoking and socioeconomic status. The OR for asthma (OR = 1.4, 95% CI : 0.9-2.1) and pneumonia (OR = 1.5, 95% CI : 1.0-2.3) were also elevated. The risk of lung cancer remained significant for pulmonary tuberculosis and chronic bronchitis/emphysema when analysis was limited to the pathologically confirmed cases and self-responders. CONCLUSIONS: This study provides additional evidence that previous pulmonary tuberculosis and chronic bronchitis/emphysema are causally related to lung cancer, although the precise mechanism is still unclear. The results for asthma and pneumonia, while suggestive of a positive association, did not reach the traditional level of statistical significance and should be interpreted with caution.

Adult↗

PubMed1994

Clinical aspects and treatment outcome in HIV-associated pulmonary tuberculosis: an experience from a Thai referral centre.

This case-control study examined the impact of HIV infection on clinical presentation, response to treatment, and outcome of pulmonary tuberculosis. Symptoms, radiographic pattern, sputum direct smear, drug susceptibility, treatment outcome and adverse reactions of 88 HIV-infected patients with newly-diagnosed, culture-proved, untreated pulmonary tuberculosis were compared with those of age and gender-matched HIV-seronegative patients. No differences in the frequency of pyrexia, dyspnoea, cough or haemoptysis were evident. Cavitary lesions and upper zone infiltrates were observed significantly less often in the HIV-infected group (p = 0.02 and 0.01, respectively). Direct smear positivity was comparable in the 2 groups. The resistance rates to antituberculous drugs were not different except for Streptomycin which was higher among the HIV-infected patients (p = 0.01). Cutaneous hypersensitivity reactions and drug-induced hepatitis occurred more often in the HIV-seropositive group, albeit not reaching statistical significance. Default was much higher in the HIV-infected patients (33%); however, the culture conversion rate was satisfactory among those completed treatment. Twelve HIV-infected patients died during the course of treatment, four of whom as a result of tuberculosis. Based on these observations, physicians should maintain a high index of suspicion for tuberculosis among HIV-seropositive patients for short-course chemotherapy to be promptly instituted.

AIDS-Related Opportunistic Infections↗

PubMed1991

Autopsy diagnosis versus clinical diagnosis, particularly in malignant disease. Comparison of two periods: 1961-70 and 1978-87.

We present a comparison of autopsy records in the Institute of Pathology of Münster University during 1961-70 with those from 1978-87. The study was based on 11,716 autopsy cases in which reliable documentation of clinical diagnosis could be adequately correlated and compared with the respective autopsy diagnoses. In the decade 1961-70, 34% of the clinical diagnoses were correct, 15% were nearly correct and 23%, incorrect (24% had to be supplemented without relevance to therapy or prognosis, 4% side diagnoses). In the decade 1978-87, 50% of the clinical diagnoses were correct, 15% nearly correct and 18% incorrect (17% supplemented). With respect to malignant tumours, in 1961-70 clinical diagnoses were correct in 37% of cases and incorrect for 26%; in 1978-87, 47% were correct and 15% incorrect. This comparison covered all major tumour locations. The difference in incorrect clinical diagnoses between the two periods is statistically significant. With respect to infectious diseases, the concordance between clinical and autopsy diagnoses is even poorer. Lues (syphilis) is now rarely recognized in clinical diagnoses, even though it may be fatal; 50% of tuberculosis patients die from miliary tuberculosis without a correct diagnosis. Endocarditis in all its forms was underdiagnosed clinically in 75% of cases. These data provide substantial arguments in favour of autopsy control of clinical diagnosis, also including histological findings in biopsy specimens.

Autopsy↗

PubMed2003

Resistance patterns of Mycobacterium tuberculosis complex isolates in the Turkish Army from 1998 to 2000.

The aim of this retrospective study was to investigate susceptibility rates of Mycobacterium tuberculosis complex (MTBC) isolates against streptomycin, rifampicin, isoniazid, and ethambutol between January 1998 and December 2000 in the Turkish Army. Specimens collected from patients were cultured both conventionally and radiometrically. Differentiation of MTBC bacteria from Mycobacteria other than tuberculosis bacilli was made by the BACTEC p-nitro-alpha-acetyl-amino-beta-hydroxypropiophenone test. Susceptibility testing of MTBC isolates was performed using the BACTEC radiometric susceptibility assay for mycobacteria. Most of the specimens originated from respiratory system. A total of 98 isolates in 1998, 123 isolates in 1999, and 84 isolates in 2000 were obtained and identified as MTBC using the radiometric BACTEC TB460 system. Initial resistance was most frequent to isoniazid followed by ethambutol, streptomycin , and rifampicin in this study period. The differences between resistance rates were not statistically significant on an annual basis. None of these isolates was resistant to all four antimycobacterial agents. Although resistance rates of our isolates were not as high as previously reported by some authors from Turkey and there was no significant difference between the annual susceptibility rates, routine screening of antituberculosis drug susceptibility should be continued to control the resistance development and its spread.

Antitubercular Agents↗

PubMed2002

CD4+ and CD8+ lymphocytes and clinical features of HIV seropositive Nigerians on presentation.

Eighty of 200 HIV seropositive patients admitted in the medical wards of Ahmadu Bello University Teaching Hospital, Zaria from year 1995 to 1997 were studied on presentation and compared to 40 age and sex matched controls. The main clinical features observed included weight loss, pyrexia, diarrhoea, lymphadenopathy, anaemia and pruritic dermatosis. Sixty-two of the 80 patients (73.2%) presented at stages 3 and 4 of WHO Clinical and Laboratory staging. Thirty (30) percent of these patients died between a period of one to four months after presentation. The main diseases complicating HIV infection at presentation of the 80 patients were Mycobacterium tuberculosis infection (30%), acute bacterial infections (with Salmonella typhi, Streptococcus pneumoniae and Staphylococcus aureus) (24%), candidiasis (14%) and Kaposi sarcoma (2%). Seropositivity for HIV types was found to be HIV-I alone in 43.5% of cases; HIV-II alone in 14% and both HIV-I and II in 42% of cases. Risk factors associated with HIV infection were multiple sexual partners (73%), sexually transmitted disease (70%), and unscreened blood transfusion (1%). HIV positive patients had a mean CD4+ T-cells of 0.24 x 10(9) +/- 0.17 which was significantly lower than the mean of 0.6 +/- 0. 17 x 10(9)/L for controls (P < 0.05 students t-test). Thirty (35%) of the patients had CD4+ counts of less than 0.2 x 10(9)/L (200 cells/microl) at presentation. The mean CD3+ lymphocytes count was 0.51 +/- 0.24 x 10(9)/L for patients and 1.04 +/- 0.71 x 10(9)/L for controls. The mean CD8+ lymphocyte count in patients was 0.29 +/- 0.19 x 10(9)/L and 0.44 x 10(9)/L for controls. Both CD3+ and CD8+ lymphocyte populations were statistically lower in patients than controls (P < 0.05).

AIDS-Related Opportunistic Infections↗

PubMed2006

The predictive value of serum procalcitonin levels in adult patients with active pulmonary tuberculosis.

The aim of our prospective study was to evaluate the predictive value of serum procalcitonin (PCT) level in comparison with C-reactive protein level and erythrocyte sedimentation rate for the diagnosis of pulmonary tuberculosis (PTB) on admission and 6 months after the administration of anti-tuberculous chemotherapy (ATCT). Seventy-five adult male patients with active PTB who were mycobacteriologically diagnosed (smear and culture positivity) were examined in this study. As a control group, 75 healthy adult males were enrolled. The measured serum PCT levels were within the normal range both in healthy individuals and in patients 6 months after ATCT. Serum PCT levels had been slightly high on admission in patients with PTB in comparison with controls (P = 0.01) and patients who had ATCT (P = 0.001), and this difference was statistically significant, but the PCT levels of most cases with PTB (58.7%) were below the usual cut-off level (0.5 ng/mL). We conclude from this study that the serum PCT level was not a reliable indicator in the diagnosis of active PTB because of its low sensitivity (41.3%), and in most cases it was not capable of overcoming the cut-off level even if statistically meaningful results were obtained. The PCT test for the presumptive diagnosis of PTB cannot be substituted for microbiological, epidemiological, clinical and radiological data.

Adult↗

PubMed2000

[Effectiveness of the surgical treatment of patients with pulmonary tuberculosis and multidrug resistance of its causative agent].

In 1996-1998, the Central Institute of Tuberculosis, Russian Academy of Medical Sciences performed more than 600 operations. Of them 90 (15%) patients isolated mycobacteria. The drug resistance of M. tuberculosis was found in 69 (76.7%) patients. In 60.9% of cases, the resistance of M. tuberculosis to isoniazid and rifampicin was concurrently accompanied by that to one (21.4%), two (61.0%), and even 3 (14.8%) tuberculostatics. Removal of the lung or its remnants in the extrapleural layer was most common (67.7%); thoracic cavernomyoplastic operations were made in 17.4% of cases, and partial resections accounted for only 13%. Postoperative complications were more frequently encountered in patients with drug-resistant tuberculosis than in controls (6.7%). Among them, tuberculosis progression and empyema were prevalent (13%). The clinical efficiency and duration of surgical treatment were directly related to the rates of progression and to the magnitude of drug-resistance of Mycobacteria.

Antibiotics, Antitubercular↗

PubMedDate not supplied

Proline-oxidase and hydroxypyroline-2-epimerase activities in experimental fibrosing granulomatous processes of the lung.

Three experimental fibrosing granulomatous processes of the lung (pulmonary granulomas induced by complete Freund adjuvant, viral pneumonitis induced by the A2 influenza virus, and tuberculosis induced in animals exposed to tobacco smoke) were produced in rabbits and the results confronted in view of establishing some relationships between mesenchymal cell accumulations, reticulin fibrillogenesis, and the enzymic activities of proline-oxidase (PO) and of hydroxyproline-2-epimerase (HEP), enzymes intervening in the control of hydroxyproline incorporation in the procollagen molecule. Histopathologic, histochemical and histoenzymic methods, quantification of cells and fibrils, statistical analyses, including the regression lines method, were used. The confrontation of the three processes made obvious that the cell accumulation invariably preceded the fibrillogenetic process, that the immune nature of the process was accompanied by larger cell accumulations than the non-immune one, that between cell accumulations and fibrillogenesis there existed highly significant correlations, and that the increase of the enzymic activities of proline-oxidase and of hydroxyproline-2-epimerase always accompanied these tissular changes, being topographically coincident with them (interlobular areas, alveolar walls).

Amino Acid Oxidoreductases↗

PubMed1998

Limitations and requirements for quality control of sputum smear microscopy for acid-fast bacilli.

Sputum microscopy for acid-fast bacilli (AFB) is considered to be the most appropriate method for case-finding in a tuberculosis (TB) control programme. It is usually carried out by general technicians, often after minimal training. Quality control of their results therefore seems indispensable. The methods advocated for quality control are reviewed. Controls by culture leave too much uncertainty because of big differences in technical characteristics of the methods. Sets of smears sent out by a central laboratory can only be used to assess capability. Rechecking routine smears allows daily performance to be appraised and may be a strong motivation, but feasibility may be a problem. Based on our experience, we describe the technical requirements for cross-checking of routine smears. Counter-checking slides with discordant results is crucial for accurate assessments. A sample size should strike a balance between statistical accuracy and the man-power needed. Indicators for evaluation are proposed that allow discrimination of error gradings, to be used in a phased manner with priority at first being given to false negatives and false positives that pass the threshold for clinical decision-making. Estimates of critical values with suggestions about their interpretation are placed in the context of supervising TB laboratories.

Bacteriological Techniques↗

PubMed1998

Cytologic features of mycobacterial pleuritis: logistic regression and statistical analysis of a blinded, case-controlled study.

Tuberculous pleural effusions are characterized by lymphocytosis; the significance of mesothelial cells is uncertain, as are the cytologic features in concurrent human immunodeficiency virus (HIV) infection. This blinded study compared 38 culture-positive pleural fluids (6 HIV+) with 38 controls from benign exudative processes. Logistic regression analysis selected mature lymphocytes as most predictive of positive culture, and mesothelial cells and eosinophils as negative predictors. Mesothelial cells were scant (< 10% of nucleated cells) in 36/38 cases with mycobacteria (sensitivity 95%); if these cell were > 10%, tuberculosis was virtually ruled out in HIV- patients. Specificity was maximized (82%) when mesothelial cells < 10% were combined with lymphocytes > 50%; positive predictive value with this combination was 76%, but was raised to 96% if moderate/marked cellularity was also identified. Among tuberculosis cases, reactive mesothelial cells differentiated HIV+ from HIV- patients; there was no other significant difference.

Acquired Immunodeficiency Syndrome↗

PubMed1976

Clinical assessment of the MOD-MEM cancer test in controls with non-malignant diseases.

A control series of 105 patients in hospital with non-malignant diseases was used in a limited clinical assessment of the MOD-MEM test. Twenty-seven positive results could be explained on the basis of destruction of nervous parenchyma, tissue necrosis, tuberculosis, malignant disease, etc. The remaining 13 unexplained positives showed a sex and age distribution in agreement with that predicted from cancer registration statistics if the MOD-MEM test detects cancer about 16 years before the clinical appearance of the disease.

Evaluation Studies as Topic↗

PubMed2006

Interleukin-10 (IL-10) gene polymorphism as a potential host susceptibility factor in tuberculosis.

Several genes encoding for different cytokines may play crucial roles in host susceptibility to tuberculosis (TB), since the cytokine production capacity varies among individuals and depends on the cytokine gene polymorphism. The association of the cytokine gene polymorphisms with the development of TB was investigated in this study. DNA samples were obtained from a Turkish population of 81 patients with the different clinical forms of TB, and 50 healthy control subjects. All genotyping (IL-6, IL-10, IFN-gamma, TGF-beta and TNF-alpha) experiments were performed using sequence-specific primers PCR (PCR-SSP). Analysis of allele frequencies showed that IL-10 -1082 G allele frequency was significantly more common in TB patients than healthy controls (37.7% vs 23.0%, p: 0.014). No statistically significant differences were observed between the different clinical forms of the disease. These results suggest that the polymorphisms in IL-10 gene may affect susceptibility to TB and increase risk of developing the disease. To confirm the biological significance of our results, further studies should be performed on other population groups.

Alleles↗

PubMed2004

[Factors associated with the presence of tuberculosis in patients with acquired immunodeficiency syndrome in Cuba].

OBJECTIVES: To determine the factors associated with the development of tuberculosis in patients with acquired immunodeficiency syndrome (AIDS) and to identify the most frequent symptoms and signs of tuberculosis in this group of patients. METHODS: This retrospective observational case-control study was carried out with 143 patients diagnosed with AIDS who were discharged from the Pedro Kourí Institute of Tropical Medicine, which is in the city of Havana, Cuba, between January 1997 and March 2001. The cases were 72 patients with AIDS and some clinical form of tuberculosis, while the control group was made up of the first 71 AIDS patients without tuberculosis who were discharged. The following variables were evaluated: AIDS stage before the study, serious opportunistic infections suffered before the diagnosis of tuberculosis (pulmonary pneumocystosis, cerebral toxoplasmosis, systemic candidiasis, isosporiasis, and recurrent pneumonia), concentration of CD4+ T lymphocytes, and clinical symptoms and signs of tuberculosis. The primary data were taken from the clinical files of the patients. We calculated the frequency of the nominal qualitative variables and the crude odd ratios (ORs) and their 95% confidence intervals (CIs). The statistical association among the variables was determined with the chi-square test with Yates correction. The individual effect of each variable was assessed through multivariate logistic regression analysis. The level of statistical significance was 0.05. RESULTS: Tuberculosis in this group of patients showed a statistically significant association with: being ill with AIDS before the study (OR = 3.57; 95% CI: 1.78 to 7.17); a history of pulmonary pneumocystosis (OR = 4.73; 95% CI: 1.51 to 15.76), cerebral toxoplasmosis (OR = 6.22; 95% CI: 1.21 to 42.99), or systemic candidiasis (OR = 11.29; 95% CI: 1.40 to 246.5); and having CD4+ T lymphocyte concentrations lower than 200 cells/mm(3). However, the logistic regression showed a significant association only with the history of systemic candidiasis (OR = 10.47; 95% CI: 1.06 to 103.5; P = 0.0446). The symptoms associated with the clinical diagnosis of tuberculosis were hemoptysis (OR = 7.54; 95% CI: 1.88 to 170.34), fever of unknown origin (OR = 13.38; 95% CI: 5.55 to 32.96), night sweats (OR = 21.95; 95% CI: 4.66 to 142.43), and weight loss (OR = 3.52; 95% CI: 1.65 to 7.55). The associated signs were regional lymphadenopathies (OR = 10.00; 95% CI: 1.22 to 220.3), hepatomegaly (OR = 5.44; 95% CI: 1.76 to 17.95), and splenomegaly (OR = 5.08; 95% CI: 1.63 to 16.83). CONCLUSIONS: The symptoms and signs seen most frequently in the patients with AIDS and tuberculosis are the characteristics of tuberculosis in patients without AIDS. In patients with AIDS, tuberculosis can be associated with other diseases whose symptoms are similar to those of tuberculosis. Nevertheless, these results indicate that the traditional symptoms of tuberculosis can help diagnose tuberculosis in this group of patients.

Adult↗

PubMed1992

Prevalence of tuberculous infection among U.S. residents of Cuban descent--Dade County, Florida, 1982-84.

The strategic plan to eliminate tuberculosis (TB) in the United States emphasizes the need for improved understanding of the epidemiology of tuberculous infection among recent immigrants and other groups at increased risk for TB (1). Data regarding the prevalence of tuberculous infection are limited for groups such as U.S. residents of Cuban descent (i.e., Cubans) and other minority populations. To estimate the prevalence of tuberculous infection among self-reported Cubans, CDC's National Center for Health Statistics analyzed data from tuberculin skin testing performed on all examinees aged 6 months to 74 years in Dade County (which includes incorporated Miami), Florida (1990 population: 1.9 million; Hispanic population: 950,000), during the first Hispanic Health and Nutrition Examination Survey (HHANES), 1982-84 (2).

Adolescent↗

PubMed1999

Isoniazid prophylaxis for tuberculosis in HIV infection: a meta-analysis of randomized controlled trials.

OBJECTIVES: To evaluate the efficacy of isoniazid for the prevention of tuberculosis in tuberculin skin test-positive and negative individuals with HIV infection. DESIGN: Meta-analysis of randomized controlled trials. SETTING: Seven trials from Mexico, Haiti, the United States, Zambia, Uganda and Kenya. PATIENTS: Individuals free from tuberculosis, 2367 persons in the intervention and 2162 in the control groups. INTERVENTION: Comparison of isoniazid with placebo or no prophylaxis. METHODS: A systematic search of the literature was carried out from 1985 to October 1997 for randomized controlled trials of isoniazid prophylaxis in HIV-infected persons. Two reviewers evaluated the relevance of each candidate study and the validity of eligible trials. Studies were pooled using a random effect model, conducting secondary analyses for tuberculin skin test-positive and negative persons. RESULTS: Mean follow-up in trials varied between 0.4 and 3.2 years. Pooling all seven trials, a risk ratio was found for persons treated with isoniazid for developing tuberculosis of 0.58 [95% confidence interval (CI), 0.43-0.80] and 0.94 (95% CI, 0.83-1.07) for death. In groups of tuberculin skin test-positive and negative persons, the risk ratio of tuberculosis was 0.40 (95% CI, 0.24-0.65) and 0.84 (95% CI, 0.54-1.30), respectively, and the difference in the effectiveness of isoniazid versus placebo between these groups was statistically significant (P = 0.03, for the difference of summary estimates). Consistency of results was found across trials (P > 0.10, heterogeneity value) for all comparisons. CONCLUSIONS: Prophylaxis with isoniazid reduces the risk of tuberculosis in persons with HIV infection. The effect is restricted to tuberculin skin test-positive persons.

AIDS-Related Opportunistic Infections↗

PubMed1974

Tuberculin sensitivity and skin lesions in children after vaccination with 11 different BCG strains.

In previously published studies, a number of BCG strains used in several production laboratories were compared in animal models. Liquid vaccines from the different strains were prepared in one laboratory with a uniform technique, the aim being to obtain uniform in vitro properties. In the studies reported here, such vaccines were compared by means of vaccinating children in India and Denmark and then measuring their post-vaccination skin lesions and tuberculin sensitivity. One strain induced delayed hypersensitivity strikingly weaker than that induced by any of the others, although the vaccine was in no way inferior in terms of exhaustive in vitro tests. Differences among the other strains were slight, although sometimes statistically significant. The implications of such differences are discussed.

Adolescent↗