Some aspects of specimen collection and stability in trace element analysis of body fluids

Analyses for trace elements in biological fluids are uniquely susceptible to extreme errors unless special precautions are taken during collection, storage, and analysis. The integrity of the specimen may be compromised before it is analyzed, by contamination during collection and processing or by attenuation of the analyte concentration during storage. If this happens, determined values are not valid even though the method of analysis is extremely sensitive and highly accurate. Obstacles to obtaining precise and accurate analytical data arising from these factors are discussed. We consider control procedures applicable at all stages for ascertaining the sources of error and eliminating them.

Selection for increased 12-day litter weight in mice

Selection for increased 12-day litter weight of standard litters of eight mice was practiced for nine generations in a replicated experiment with controls. The two selection lines followed very similar patterns of response. The pooled realized heritability was 0.08±0.04 and the observed genetic gain was 0.57 ± 0.19 g per generation. The replicated controls showed a negative trend in 12-day litter weight which was likely due to the effects of inbreeding and possibly some detrimental environmental fluctuation. Derivations of the components of variance affecting 12-day body weight indicated that direct additive genetic variance arising from genes controlling growth from birth to 12 days of age accounted for 37.0% of the total variation, while maternal additive genetic variance and postnatal maternal variance accounted for 16.4% and 49.6% of the variance, respectively. The direct additive genetic-maternal genetic covariance was negative but small. Significant positive correlated responses were observed for 12, 21, 42 and 56-day body weight, but no correlated responses were observed for postweaning body weight gain or for reproductive efficiency measured as number born and percent fertile matings.

Rapid Phytochrome-mediated Changes in Adenosine 5'-Triphosphate Content of Etiolated Bean Buds

This study was designed to determine the effects of red and far red irradiation on ATP metabolism in etiolated bean buds (Phaseolus vulgaris L. var. Red Kidney). Compared to dark controls, red irradiated buds show an initial decline in ATP content at 15 seconds following a 5-minute irradiation. ATP content then rapidly rises to a peak at 1 minute, and then slowly returns to the baseline. The 1-minute promotion of ATP content is red/far red reversible. Acetylcholine does not appear to mimic red light in this system; it causes a marked decrease in ATP content.

Direct and correlated responses to selection for increased postweaning gain in mice

Mass selection for increased body weight gain from 21 to 42 days of age was practiced for 12 generations in four replicate lines of ICR-albino mice. Response to selection averaged 0.56±0.03 g. per generation. This response represented an increase of 7.0 genetic standard deviation units and 3.4 phenotypic standard deviation units in 12 generations. The realized heritability pooled over the four replicates was 0.24±0.02. Sizable positive correlated responses were found for 42 and 56-day weight and gain from 42 to 56 days. Much smaller positive correlated responses were noted for 12-day litter weight and 12-day individual weight. Neither litter size nor weaning weight were significantly altered by selection for increased postweaning gain. Reproductive efficiency measured as percent fertile matings declined significantly in the selected lines.

A report on the interlaboratory quantitation of haemoglobin A2 and haemoglobin F

An interlaboratory trial of the quantitation of Hb A(2) and Hb F has been carried out on two samples of blood by 90 laboratories in the British Isles. The results have been compared with those obtained by four reference laboratories. Overall, the correlation was very poor and indicated that the methods used have to be standardized before interlaboratory values become meaningful. Moreover, in many laboratories the level of Hb A(2) in a patient with proven beta thalassaemia was not reported as being increased.

Familial polycythaemia caused by a new haemoglobin variant: Hb Heathrow, beta 103 (G5) phenylalanine leads to leucine

A new variant of haemoglobin A (Hb A) with a high affinity for oxygen has been found in an English family. Five members are affected and all are polycythaemic. This variant (Hb Heathrow) is the first of this class to be found in this country and has the same electrophoretic mobility as Hb A. It was discovered only by measuring the oxygen affinity of the patients' red cells. This emphasizes the need for measuring the oxygen affinity of haemoglobin in patients with polycythaemia if other clinical and haematological features associated with polycythaemia rubra vera are absent.

Fat embolism in sickle cell disease

Fat embolism is a known complication of marrow infarction in patients with sickle cell disease (Hb S/S and Hb S/C) disease. It should be considered in sickle cell crisis when there is deterioration in respiratory function, a fall in arterial PO(2), a normoblastaemia, and a thrombocytopenia in the peripheral blood. We now report a patient in whom the diagnosis was confirmed in life by identifying fat in the sputum, demonstrating disseminated intravascular coagulation, and using a double isotope technique to distinguish recent from old marrow infarction. Use of these features enabled an early diagnosis to be made which led to a successful outcome in a potentially fatal condition.