Is asymptomatic bronchial hyperresponsiveness an indication of potential asthma? A two-year follow-up of young students with bronchial hyperresponsiveness

To determine the possibility that asymptomatic bronchial hyperresponsiveness (BHR) develops into symptomatic asthma, a two-year follow-up study was conducted in 81 students (48 male, 33 female; 11 to 17 years) who were found to have BHR in a 3,067 population survey (BHR group). Eighty-eight age-matched students (48 male, 40 female) with normal bronchial responsiveness served as control subjects. Daily symptom cards were recorded. Peak expiratory flow rate was measured for 24 h when symptoms occurred. Histamine inhalation tests were performed at the beginning of the study and at the end of the first and the second year. In the BHR group, 58 students remained bronchial hyperresponsive at the end of follow-up. Nine of 31 students with initially diagnosed bronchial asthma had their symptoms relieved entirely, but ten asymptomatic students developed asthma. The incidence of newly diagnosed asthma (12.5 percent in the BHR group or 20 percent in the asymptomatic BHR group) and the total percentage of diagnosed asthma (39.5 percent) in the BHR group were significantly higher than those (2.27 percent, 2.27 percent) in the control group. FVC and FEV1 showed no significant difference between two groups. PD20 FEV1 values in newly diagnosed asthmatics were significantly lower than those in asymptomatic students both at the beginning (3.05 +/- 1.56 mumol vs 6.14 +/- 1.60 mumol, p < 0.05) or the end (3.47 +/- 1.73 mumol vs 6.55 +/- 1.51 mumol, p < 0.05). The percentage of early respiratory illness was significantly higher in those with newly diagnosed asthma (80 percent) than in asymptomatic students (22.3 percent), but atopic index and the percentage of parental asthma showed no difference between two groups. In nine asthmatics whose symptoms were relieved entirely in the two-year follow-up, PD20 FEV1 was undetectable within the cumulative dose of 7.8 mumol of histamine in three students and rose from 4.58 +/- 1.85 mumol to 7.62 +/- 1.02 mumol in the remaining six. The higher the BHR, the more likely the students developed asthma. About 45 percent of asymptomatic students with PD20 < or = 3.2 mumol developed asthma in the following two years and 80 percent of them had a history of early respiratory illness, suggesting that they may have subclinical or potential asthma.

Distinction of low grade from high grade human ovarian carcinomas on the basis of losses of heterozygosity on chromosomes 3, 6, and 11 and HER-2/neu gene amplification

We examined the frequencies of loss of heterozygosity at 13 different loci distributed on 9 chromosomes in 30 human ovarian carcinomas. The same tumors were also examined for the presence of amplification of the HER-2/neu and H-ras protooncogenes. The results confirmed earlier findings that losses of heterozygosity occurred at nonrandom frequencies on chromosomes 3, 6, and 11 in these tumors. None of the tumors examined showed amplification at the H-ras locus. The HER-2/neu gene, however, was amplified in approximately one-third of the tumors, in agreement with earlier studies from other laboratories. We subdivided our tumor specimens according to their histological grades, which can be regarded as representing different stages of tumor progression. Losses of heterozygosity on chromosomes 3 or 11 were not seen in low grade lesions, although they were present in most of the high grade tumors examined. Losses of heterozygosity on chromosome 6 as well as HER-2/neu amplification, in contrast, were present in several low grade tumors and were not more frequent in high grade lesions. We conclude that the latter two abnormalities are associated with cellular functions involved at earlier stages of ovarian tumor development, whereas inactivation of genes on chromosome 3 or 11 is associated with later steps that may be incompatible with the well differentiated phenotype.

[Sulfur dioxide-induced bronchial constriction in asthmatics and its prophylaxis by salbutamol]

Patients with bronchial asthma often develop acute attack in kitchen while burning honeycomb briquet which is widely used for cooking in southern China. Burning of a honeycomb briquet produces 0.6-4.3 ppm sulphur dioxide (SO2) in the kitchen air. To assess whether the above concentration of SO2 can induce bronchial constriction, we performed SO2 bronchial provocation test on 21 asthmatics (male 11, female 10, average age 28.8 +/- 2.0 years), 10 patients with allergic rhinitis (male 3, female 7.28 +/- 1.6 years) and 20 healthy non-smokers (male 13, female 7, 28.1 +/- 1.5 years). FEV1 showed no significant change in both healthy and rhinitis group even a maximal amount of SO2 (10 ppm) was given. The calculated PC20 FEV1 and PC35 SGaW in asthmatics were 3.7 +/- 0.22 ppm and 2.5 +/- 0.18 ppm respectively, which fell into the SO2 range yielded by a burning honeycomb briquet. Orally administered slow release salbutamol created protective effect in 5 out of 8 patients. Salbutamol inhalation, however, completely blocked SO2 induced bronchial constriction. We suggest that patient with bronchial asthma should receive salbutamol aerosol inhalation before cooking with burning honeycomb briquet.

Observation of periodicity multiplication in a synchronously pumped dye laser

By tuning the cavity length of a synchronously pumped dye laser, many stable operating points were observed, where the periodicity of the dye laser was an exact rational multiple of that of the pumping argon-ion laser. The multiplication ratio was also found to be dependent on the pumping laser power. Output with 14 times the pumping periodicity has been observed in the time domain. Twenty-six times the pumping periodicity has been observed in the frequency domain. This system can be used to study the phenomena of optical chaos at high repetition frequencies in the visible.