Effect of air pollution on peak expiratory flow rate variability.

Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects.     

Computed tomography of the abdomen with fat density oral contrast medium.

A 12.5% corn oil-emulsion (COE) was tested as an oral contrast agent for abdominal computed tomography (CT) examinations in 100 patients. The results were compared with those obtained from another group of patients who received a conventional, high-density, oral contrast agent (2-3% iodinated solution). There was no statistically significant difference in the subjects' tolerance to the two agents (P greater than 0.05). There was, however, a significant improvement in image quality with COE (P less than 0.05). Gastrointestinal tract discrimination, and mucosal and mural visualisation was of higher quality with fat density oral contrast medium than with the high-density contrast agent. These data suggest that COE should be considered for routine use as an alternative to conventional high density oral contrast agents in upper abdominal CT.     

Mosaicism for an FMR1 gene deletion in a fragile X female

Most cases of fragile X syndrome result from expansion of CGG repeats in the FMR1 gene; deletions and point mutations of FMR1 are much less common. Mosaicism for an FMR1 full mutation with a deletion or with a normal allele has been reported in fragile X males. Here we report on a fragile X female who is mosaic for an FMR1 full mutation and an intragenic deletion. The patient is a 4-year-old girl with developmental delay, autistic-like behaviors, and significant speech and language abnormalities. Southern blotting demonstrated the presence of a methylated full mutation, a normal allele in methylated and unmethylated forms, and an additional fragment smaller than the normal methylated allele. This result indicates that the patient is mosaic for a full mutation and a deletion, in the presence of a normal allele. By DNA sequence analysis, we mapped the 5' breakpoint 63/65 bp upstream from the CGG repeat region and the 3' breakpoint 86/88 bp downstream of the CGG repeats within the FMR1 gene. The deletion removed 210 bp, including the entire CGG repeat region. The full mutation was inherited from a premutation in the patient's mother. The deletion, which remained methylated at the Eag I and Nru I sites, was probably derived from the full mutation allele. Mosaicism of this type is rare in females with a fragile X mutation but should be kept in mind in the interpretation of Southern blots.     

Presence and measurement oftele-methylhistamine in mast cells

The histamine metabolitetele-methylhistamine (t-MH) was identified and measured in crude and purified peritoneal mast cells (MCs). Peritoneal dialysates, peritoneal cells, and purified MCs all containedt-MH in concentrations representing about 0.2% of the corresponding histamine (HA) levels.T-MH levels in crude cells represented about 70% of the total dialysate levels, indicating the presence of extracellular as well as intracellulart-MH.T-MH levels per MC in purified fractions were similar to those of crude fractions, indicating a MC origin for the intracellulart-MH. Histamine methyltransferase activity was not detected in crude or purified MC fractions, and incubations with the monoamine oxidase inhibitor pargyline failed to increase the content or release oft-MH in either fraction, suggesting a very slow or non-existent histamine methylation in MCs. Compound 48/80 produced a temperature-dependent release of HA andt-MH in crude and purified preparations, and Triton X-100 also released both amines. In all cases, the degree of release of both amines was correlated, consistent with a granular origin fort-MH in MCs. The low concentrations oft-MH in MCs do not necessarily indicate a role for MCs in HA metabolism, but suggest thatt-MH may be a valuable marker for non-MC HA.     

Interaction of polystyryl radical with copper(II) complexes

The polymerization of styrene initiated by 2,2′-azoisobutyronitrile (AIBN) was studied in N,N-dimethylformamide (DMF) solution at 60°C in the presence of tetrakis(N,N-dimethylformamide)copper(II) perchlorate, and also in the presence of its monoazido copper(II) complex [Cu(DMF)₃N₃]⁺. The monoazido complex in DMF was prepared in situ by mixing solid sodium azide with tetrakis(N,N-dimethylformamide)copper(II) perchlorate in a mole ratio of 1:1. The nature of the complex was established by Job's method. The equilibrium constant K for the reaction [Cu(DMF)₄]²⁺ + N ? [Cu(DMF)₃N₃]⁺ + DMF determined by the limiting logarithmic method was found to be 1,25 · 10⁴l · mol^?1. The presence of [Cu(DMF)₄]²⁺ ions in the polymerization systems caused retardation, but [Cu(DMF)₃N₃]⁺ ions produced well defined induction periods. The rate constants at 60°C for the interaction of polystyryl radical towards [Cu(DMF)₄]²⁺ and [Cu(DMF)₃N₃]⁺ ions were calculated to be 6,6 · 10² and 5,74 · 10⁴ l · mol^?1 · s^?1, respectively.