Nitrogen dioxide exposure and urinary excretion of hydroxyproline and desmosine

The relationship between average and peak personal exposure to nitrogen dioxide and urinary excretion of hydroxyproline and desmosine was investigated in a population of preschool children and their mothers. Weekly average personal nitrogen dioxide exposures for subjects who resided in homes with one or more potential nitrogen dioxide source (e.g., a kerosene space heater, gas stove, or tobacco smoke) ranged between 16.3 and 50.6 ppb (30.6 and 95.1 micrograms/m3) for children and between 16.9 and 44.1 ppb (12.8 and 82.9 micrograms/m3) for mothers. In these individuals, the hydroxyproline-to-creatinine and desmosine-to-creatinine ratios were unrelated to personal nitrogen dioxide exposure--even though continuous monitoring documented home nitrogen dioxide concentration peaks of 100-475 ppb lasting up to 100 h in duration. Significantly higher hydroxyproline-to-creatinine and desmosine-to-creatinine ratios were observed in children, compared with mothers (p < .001 and .003, respectively).

Lindane toxicity in an infant

A four-month-old infant with severe impetigo who had prolonged daily applications of lindane presented with two seizure episodes. His blood lindane level was 1.27 ppm. Caution should be exercised when using lindane in infants and children. Proper instruction and close supervision are essential.

Scabies infestation: the effect of intervention by public health education

The objectives of this study were to determine the prevalence of scabies in an infested village; to educate the residents on self-treatment and prevention by the use of 5% monosulfiram soap; to evaluate the short term effectiveness of this intervention by determining, 2 weeks later, the compliance to self-treatment and prevention; and to determine the prevalence rate on the second visit. In 59 households (96.7% of the village) containing 313 persons, an educational session was held and a leaflet distributed on the use and availability of the soap. Thirteen persons (4.2%) from eight households (13.6%) had scabies. After 2 weeks, 7 persons (2.2%) (2 persisting and 5 new cases) from 5 households (8.5%) were infested. Thus a cure rate of 85% was obtained though the prevalence rate showed no statistically significant difference. Among the under 15 year olds, the numbers infected decreased from 10 to 3 while among the over 15 years olds, the numbers infected increased from 3 to 4, neither reading significance at the 5% level.

Immunophenotypic and HLA studies in childhood acute lymphoblastic leukemia in Trinidad, West Indies

Between October 1983 and May 1986, 17 cases of childhood acute lymphoblastic leukemia (ALL) were admitted to the General Hospital, Port of Spain, Trinidad. Fifteen of those cases were under 10 years of age, seven of whom presented with joint or bone pains. Boys outnumbered girls by almost 5:1 and the ethnic distribution showed a preponderance of patients of East Indian origin. At last follow-up (May 1989), the survival rate of the 15 under-10-year-old patients was 71%. Immunophenotype studies on nine of the 17 patients revealed six carrying T cell markers and three carrying markers suggestive of a pre-B phenotype. HLA tissue typing on 10 patients showed an enhanced frequency of the HLA-B40 antigen when compared with controls (p less than 0.05). This antigen was present in six of the patients typed and four carried the HLA-A2 and B40 antigens together, two of whom also carried the CW3 antigen and the other two carried untypable C antigens. Three of the four carrying HLA-A2 and B40 have died. Two of the three pre-B cases also carried the HLA-A2 and B40 antigens. HLA studies on three of the four families showed that HLA-A2 and B40 were on the same chromosome, i.e., a haplotype inherited from the mother in each case. None of the cases carried the HLA-B5 antigen although this antigen had a frequency of 37.8% in the control group (p less than 0.05). None of the controls with the HLA-B40 antigen carried the CW3 antigen. Further evidence of a disease association must await typing of the D locus antigens but current evidence would suggest an association between HLA-B40 and childhood ALL in Trinidad.

Streptococcal serotypes newly associated with epidemic post-streptococcal acute glomerulonephritis

The increasing incidence of reported scabies in Trinidad, from 24.2/100,000 population in 1984 to 59.5/100,000 in 1985, led to a careful monitoring in 1986 of all patients with post-streptococcal acute glomerulonephritis (PSAGN). There were 181 cases of PSAGN; 84 beta-haemolytic streptococcal isolates from 72 patients were sent to the Central Public Health Laboratory, Colindale, for grouping and serotyping. The PSAGN epidemic of 1986 was bimodal. Streptococci of M-type 73 appeared to be associated with the first phase (March-May) and comprised 20% of the isolates serotyped. New to Trinidad, streptococci of M-type 48 (4% of the isolates serotyped) preceded the first phase of the epidemic and were isolated from two patients with PSAGN. Provisional type (PT) 5757, also new to Trinidad, had been previously identified only among serotypes from the United Kingdom and the Federal Republic of Germany. This type was isolated from seven patients, in six from skin lesions and in one from the throat. PT 5757 occurred during the first wave of the epidemic and comprised 14% of the strains serotyped. Thus, the first wave of the bimodal epidemic involved serotypes M73, M48 and PT 5757. The more intense second phase (July-October) was associated with the previously documented nephritogenic M-type 55.

Epidemic scabies in four Caribbean islands, 1981-1988

Scabies infestation has been reported to the PAHO/WHO Caribbean Epidemiology Centre (CAREC) from Trinidad and Tobago (T&T), Grenada, Dominica, the Turks and Caicos Islands (T&CI) and, more recently, St Lucia. Epidemic scabies was being reported from T&CI in 1981 (1200/100,000 population), but there were no reports from T&T until 1982 (8/100,000). The first phase of the bimodal epidemic in Grenada occurred between 1982 and 1984 (132/100,000) and the explosive second phase from 1985 to 1987 (474-699/100,000). In T&T there was a low incidence of scabies until 1985 (0-59/100,000) and in Dominica the rate fluctuated (67-14/100,000) during the same period. From 1986 to 1988, scabies infestation reached epidemic proportions in T&T (410-709/100,000) and fluctuated in Dominica (108-117/100,000). In Tobago alone, scabies was not reported until March 1986, and by December the incidence rate was 105/100,000; by 1988 it had increased to 1124/100,000 population. Although no secondary infections have been reported from Grenada, Dominica, T&CI or St Lucia, T&T has reported increased streptococcal skin infections and epidemic post-streptococcal acute glomerulonephritis (PSAGN). The observed trend of increasing scabies infestation, increasing streptococcal isolates from skin lesions, and increasing PSAGN in T&T is noteworthy.

Rapid antigen detection in the diagnosis of group A streptococcal pyoderma: influence of a "learning curve effect" on sensitivity and specificity

To evaluate the efficacy of rapid antigen detection for diagnosis of Group A streptococcal pyoderma, lesions on 129 children were swabbed for culture and for rapid antigen detection testing. Duplicate cultures and duplicate rapid antigen tests were performed in two laboratories. The sensitivity and the specificity of the test were high, supporting the validity of this technique in diagnosing streptococcal pyoderma. Of importance, however, was the documentation of a learning curve effect on the sensitivity and specificity. There was a significant difference between the early samples and the later samples in one laboratory which had less previous experience with the rapid antigen detection test. By the time the later samples were collected, the proficiency of the first laboratory was equal to that of the second laboratory for both sensitivity and specificity. Although a learning curve effect on sensitivity and specificity of rapid antigen detection tests for Group A streptococci has been suspected, this is the first documentation of such an effect. This finding has important clinical implications for using rapid antigen detection tests for Group A streptococcal infections.

Home air nicotine levels and urinary cotinine excretion in preschool children

We examined the extent of correlation between home air nicotine levels and urine cotinine/creatinine ratios (CCR) in 27 children who attended a research day care program where they were not exposed to environmental tobacco smoke (ETS) during the daytime hours. Average concentrations of nicotine in home air were determined by active air sampling during the evening and night hours on 2 consecutive days. Urine samples for cotinine and creatinine determinations were collected before, during, and after the two sampling periods. In addition, four sequential weekly urine samples for CCR were obtained from study children to determine the extent to which single determinations of CCR were representative for individual children. Fifteen children resided in homes with smokers, and 12 did not. Urine CCR consistently distinguished most exposed and unexposed children. However, three exposed children had urine CCRs that clustered routinely around the criterion CCR (30 ng/mg cotinine-creatinine) that best distinguished exposed and unexposed children. In children exposed to ETS in the home, there was a significant correlation between average home air nicotine levels and the average logarithm of urine CCR the two mornings after the home air monitoring periods (r = 0.68; p = 0.006). In study children, urine CCRs were remarkably stable over the 1-month observation period. Rank correlation coefficients for sequential weekly determinations of CCR were consistently greater than r = 0.88; p less than 0.0001.

Serial studies on the cellular immune response to streptococcal antigens in acute and convalescent rheumatic fever patients in Trinidad

Acute rheumatic fever (ARF) has the characteristics of an autoimmune disease, triggered by cross-reactive antigens shared by the group A streptococcus and a variety of tissues including the heart, endothelium, and basal ganglia. Using two parameters of cellular reactivity, migration inhibition and blastogenic transformation, ARF patients from Trinidad show significant lymphocyte reactivity to streptococcal antigens, particularly those from an ARF associated streptococcal strain. This reactivity, studied over a 2-year period, peaked at 1 to 6 months after the acute onset and remained significantly elevated for at least 2 years. The reactivity is directed mainly toward a nonionic detergent extractable material in the cell membrane. These studies suggest a possible streptococcal strain specificity in ARF and demonstrate persistent sensitization, which explains the increased susceptibility to recurrences in the 2 years following the acute episode.

Group G streptococci in healthy school-children and in patients with glomerulonephritis in Trinidad

The group G streptococcus has generally not been considered a prominent pathogen. In a 1982 study of the colonization rate by beta-haemolytic streptococci in apparently healthy children, age 5-11 years, 25 of 69 isolates belonged to group G. This surprisingly high rate of group G colonization (14.3%) led to a retrospective study of school surveys in 1967 which showed that the colonization rate with this organism was 2.3% (range 1.3-3.5%). A review of bacitracin-sensitive streptococcal isolates from hospital admissions of patients with acute glomerulonephritis (AGN), rheumatic fever, and their siblings, between January 1967 and July 1980, was conducted. Of 1063 bacitracin-sensitive isolates, 63 were group G, and 52 of these were isolated from AGN patients and their siblings, i.e. 7 from skin lesions of AGN patients, 40 from the throats of siblings and only 5 from the skins of the siblings. The other 11 group G isolates were from rheumatic-fever patients and their siblings. Thus, the group G colonization rate fluctuates in the population. The isolation of only group G streptococci from skin lesions of patients with AGN suggests a possible association between group G streptococcal pyoderma and acute post-streptococcal glomerulonephritis.

Leukaemia mortality in Trinidad and Tobago 1957-1976

Leukaemia mortality in Trinidad and Tobago over the period 1957-1976 was reviewed. The mortality rate was stable except for an unexplained drop in the adult leukaemia mortality in 1966/67. Throughout the period, annual deaths due to leukaemia were less than one percent of the total annual deaths from all causes. The age and sex patterns of leukaemia mortality were similar to that of the United States of America but the overall mortality rate of 24 per million was low when compared with that of the USA where the rate in 1971 was 70 per million.

Suppression of cellular reactivity to group A streptococcal antigens in patients with acute poststreptococcal glomerulonephritis

Lymphocyte reactivity to group A streptococcal antigens was studied in patients with acute poststreptococcal glomerulonephritis (AGN) in Trinidad. When compared with controls, patients with AGN had significantly lower responses. This finding was most prominent in the patients who were greater than 10 years of age at onset of disease. The total number of T lymphocytes was found to be decreased in patients with AGN, and in particular, the percentage of cells bearing Fc receptors for IgG (T gamma) was low. Removal of the T gamma-cell population abrogated the lymphocyte response to streptococcal antigens. However, removal of the adherent cells resulted in enhancement of the response to the level of the normal control population. The presence of suppressor activity in the adherent cell population of older patients with AGN may be an important factor in progression of AGN to chronic disease.