Ultrasound-guided blood sampling of rabbit fetuses.

A rabbit animal model for hemolytic disease of the newborn has been previously described. However, evaluating the effects of this disease was limited to histologic and hematologic examinations of liveborn kitlings. To assess the feasibility of in utero blood sampling, we performed ultrasound-guided cardiac sampling of 50 fetuses in 16 New Zealand White does on days 26 and 27 of gestation. The overall rate of successful sampling was 80%. The procedure-related mortality declined to 35% by the third phase of the study. The mean (+/- SD) hematocrit (%) and reticulocyte values (#/100 RBCs) on day 26 were 26.3 +/- 3.3 and 35.6 +/- 5.1, respectively; values on day 27 were 31.3 +/- 4.9 and 27.5 +/- 7.6. The results of this study suggest that hematologic data can be obtained from rabbit fetuses in the majority of cases with only moderate fetal loss.     

Home blood sampling for plasma glucose assay in control of diabetes.

Estimation of plasma glucose in home blood samples is needed to improve diabetic control. Sufficiently precise measurements on capillary blood were obtained by (a) storing Reflotest glucose-oxidase strips in a desiccant container before reading and (b) collecting blood samples into a simple vacuum bottle containing potassium fluoride (assay of sodium content indicating volume of plasma collected). The precision of the methods (+/- 1 SD) was +/-0.35 mmol/1 (+/-6.3 mg/100 ml). Clinical reliability was assessed by measuring the basal plasma glucose concentration at home on different mornings in patients with maturity-onset diabetes, the day-to-day variation (+/- 1 SD) being +/-0.73 and +/-0.92 mmol/1 (+/-13.2 and +/-16.6 mg/100 ml) respectively. The mean basal plasma glucose concentration in all 84 patients with maturity-onset diabetes from three general practices was 8 mmol/1 (144 mg/100 ml), 44 of the values exceeding 6 mmol/1 (108 mg/100 ml). Improving control by monitoring the basal plasma glucose concentration in maturity-onset diabetes might help to prevent diabetic complications.     

Long-term blood sampling technique in the marmoset

A simple and reliable method for long-term blood sampling from the restrained marmoset is described. Cannulae were chronically inserted into the internal jugular vein, exteriorized and housed in a backpack system. The cannulae remained patent for 1-7 months. This system allows for rapid collection of blood samples and hence detailed analysis of circulating hormone levels.     

Wound closure in foetal rat skin.

Foetal rat skin rapidly closes an open wound in organ culture and in vivo, this possibly being unique to organs still in the morphogenetic stage. In the present study, examination was made of morphological changes in foetal rat skin during closure of open wounds inflicted at day 16 of gestation. Phase-contrast microscopy of open-wounded skin cultured in vitro indicated inward spreading of the peripheral skin to be responsible for wound closure. Wound closure in vitro was inhibited by cytochalasin B (10 micrograms/ml), not by hydroxyurea (2 mM), indicating prenatal wound closure to be mediated by regulation of the microfilament system rather than cell proliferation. During wound closure in vitro and in vivo, light and scanning electron microscopy of the peripheral skin showed cells in the periderm, the outermost layer of the foetal epidermis, to elongate centripetally and en masse, whereas the shape of underlying epidermal cells not to change. Numerous spindle-shaped cells and fibrous matrices in the mesenchyme were redistributed, becoming oriented along the wound edge. Following isolation of the mesenchyme and epidermis by treatment with Dispase and separate culturing, the capacity for wound closure in vitro was found to be retained only by the mesenchyme. Cellular activity within the mesenchyme, rather than in the epidermis, would thus appear essential to wound closure in foetal rat.     

Distribution of fibronectin in foetal tissues.

The distribution of fibronectin in tissues of four human foetuses (7-14 gestation weeks/GW) and twenty seven pig foetuses (25-114 days of gestation) was investigated using immunofluorescence and avidin/biotin methods. Fibronectin was abundant in the circulatory and gastrointestinal system and its derivates, in reticular stroma of immune organs, and in connective tissues and chorionic villi at all developmental stages.     

Use of arterialized venous blood sampling during incremental exercise tests.

Close agreement between arterialized venous and arterial pH, PCO2, and lactate has previously been demonstrated during steady-state exercise. The purpose of the present study was to compare arterialized venous and arterial pH, PCO2, K+, lactate, pyruvate, and epinephrine during the constantly changing circumstances of an incremental exercise test. Eight normal subjects undertook an incremental exercise test (increasing by 20 W/min) to exhaustion on a cycle ergometer during which simultaneous arterial and arterialized venous samples were drawn over the last 20 s of each work load. Linear regression of arterialized venous on arterial values showed that r varied from 0.97 to 0.99 for the variables examined and, therefore, showed that accurate estimates of arterial values could be made from the arterialized venous results during incremental testing. For many purposes it could be assumed that arterialized venous values equaled arterial values without serious error.     

The effect of sampling technique on some blood parameters in the rat.

When used to restrain rats while obtaining cardiac blood, there was little difference between the effects of ether, pentobarbitone sodium, and fentanyl plus droperidol on acid-base balance, haemoglobin, haematocrit, plasma protein, calcium and magnesium. The use of manual restraint increased blood acidity, plasma protein, calcium and magnesium, but decreased blood glucose. Haemoglobin and haematocrit values were higher for tail blood than for blood removed from the heart or abdominal aorta.     

Effects of repeated blood sampling on some blood parameters in freshwater fish

The effects of repeated weekly blood sampling on blood parameters were studied over a period of 22 days in a salmonid, Salmo gairdneri , and cyprinid fish, Leuciscus idus . The procedure induced mild anaemia demonstrated by decrease of red blood cell counts, haemoglobin and PCV. The changes were more marked in L. idus , which showed signs of increased red cell destruction. No significant trends could be observed in the white blood picture. The results show that blood tests are possible in individual fish, especially S. gairdneri over a long period.