Antibody response in cattle, sheep and rats to infection with gamma-irradiated metacercariae of Fasciola hepatica

Cattle, sheep and rats were infected orally with gamma-irradiated (4 krad) metacercariae of fasciola hepatica, or with normal metacercariae. The antibody response was monitored in each host to metacercarial tegument (T0), juvenile tegument (T1), adult tegument (T2) and gut antigens. The response was examined at weekly intervals for cattle and sheep throughout 15 weeks of infection and four weeks after infection in rats, using an indirect fluorescent antibody labelling technique. It was found that the irradiated metacercariae engendered a normal humoral response to T0, T1 and gut antigens in all three hosts although the antibody levels were somewhat reduced due to an early death or stunting of the flukes. T0 and T1 appeared to be antigenically similar. Antibodies against T2 appeared late in the animals infected with gamma-irradiated metacercariae and the titres attained were considerably lower than in the controls. the T2 antigen stimulus in the animals given gamma-irradiated metacercariae was probably provided by flukes which 'broke through' the developmental barrier imposed by irradiation and which were found alive at autopsy.     

Effects of gravity on tracheal mucus transport rates in normal subjects and in patients with cystic fibrosis

A noninvasive, radionuclide imaging technique for measuring the rate of mucus clearance in the trachea (RT), was used to study gravitational effects on mucus clearance in 13 patients with cystic fibrosis (CF), average age 17 years; 7 normal, nonsmoking adults, average age 26 years; and a normal subject who was recovering from an acute upper respiratory tract infection (URTI). In the upright position, nine of the CF patients and the subject with URTI demonstrated abnormal tracheal mucus clearance which approached normal when they were placed in 25 degrees headdown position. The normal subjects and two of the CF patients showed no significant difference in the RT measured in the two positions. The results of the study indicate that the force of gravity can be a major influence on tracheal mucus clearance in CF and URTI subjects. This conclusion supports the use of postural drainage as an effective form of therapy in patients with cystic fibrosis.     

Sequence of molecular events involved in induction of allophanate hydrolase

Addition of urea to an uninduced culture of Saccharomyces at 22 C results in appearance of allophanate hydrolase activity after a lag of 12 min. We have previously demonstrated that both ribonucleic acid (RNA) and protein synthesis are needed for this induction to occur. To elucidate the time intervals occupied by known processes involved in induction, temperature-sensitive mutants defective in messenger RNA transport from nucleus to cytoplasm (rna1) and in protein synthesis initiation (prt1) were employed along with an RNA polymerase inhibitor in experiments that measure cumulative synthetic capacity to produce allophanate hydrolase. These measurements identify the time within the lag period at which each of the above processes is completed. We observed that RNA synthesis, rna1 gene product function, and protein synthesis initiation are completed at 1 to 1.5, 4, and 9 to 10 min, respectively.     

Extinction coefficient of thyroglobulin

The extinction coefficient at 280 nm of the solution (pH 7,2-7,4) of thyroglobulin from normal thyroid and nodular euthyroid goiter was measured with the values of 0,6-0,7 to 0,9 ml.mg-1.cm-1. The value of E1%280 as function of the iodoamino acid content depends on the morphological state of the thyroid gland. A simple method for determination of the E1%280 value by measuring of the protein absorption spectrum is proposed.     

Measurement of response to treatment in colorectal liver metastases

Assessment of tumour response to chemotherapy is important when assessing efficacy of treatment and comparing differing therapeutic regimens. Percentage hepatic replacement (PHR) is commonly used to assess response to treatment of colorectal hepatic metastases. PHR is dependent not only on tumour volume, but also on hepatic parenchymal volume. The effect of tumour growth on hepatic parenchymal volume is unclear but is of importance owing to its effect on PHR. We assessed tumour and hepatic parenchymal weights in an animal tumour model using dissection, and tumour and hepatic parenchymal volumes in patients with colorectal hepatic metastases using CT scanning, in order to establish how hepatic parenchyma varied with change in metastasis size. There was no significant correlation between tumour and liver parenchyma in either the animal model (r = -0.03, P > 0.05) or the patient study (r = 0.3, P < 0.05). This suggests that hepatic parenchymal volume was preserved in the presence of increasing tumour volume. In a further study of computerised tomographic (CT) scans before and after treatment in patients whose tumours either responded to chemotherapy or continued to grow, change in PHR (median proportion of PHR change = 0.40) significantly (P = 0.04) underestimated the change in tumour volume (median proportion of tumour volume change = 0.56), particularly at higher (> 400 ml) volumes. There was good correlation between change in tumour volume and WHO criteria in assigning patients to tumour growth, stable disease or tumour response categories. This study suggests that, in clinical trials comparing colorectal liver metastasis treatments, metastasis volume and not PHR should be used to assess extent of disease and the effect of treatment.