Iron kinetics effects of 88 millirads. Partial-versus-total body X-irradiation

Rats were irradiated with one tibia shielded (95% marrow exposure), total body exposed (TBI, 100%), and only one tibia exposed (5%), or they were sham irradiated (SI, 0%). Plasma Fe-59 clearance time (T1/2) and Fe-59 content ratio in the right and left tibia (RT/LT) were assayed to determine the erythroid activity of the overall marrow of the animals and the relative marrow activity in the exposed and shielded tibias, respectively. When a major fraction of the overall marrow was shielded or irradiated, the overall erythroid activity levels were identical to those of the SI and TBI animals, respectively. Interestingly, enhanced normoblastosis was observed in the marrow of the exposed tibia of individual animals exhibiting normal erythroid activity in 95% of the marrow. Conversely, localized marrow with normal erythroid activity was found in a shielded tibia of individual rats, demonstrating an enhanced erythroid activity in a major fraction of the total body. It was concluded that 88 mrad can alter marrow functions in a small isolated skeletal region as effectively as in the whole body, and tandem assays of the Fe-59 T1/2 and Fe-59 RT/LT can facilitate ultra-low-dose X-ray studies involved with partial body exposures.     

Differentiation of mitotic melanoma cells from G2 cells and their isolation by use of 5-bromo-2'-deoxyuridine and propidium iodide

This report describes a method by which mitotic cells were isolated from nonsynchronized Cloudman melanoma cells that had been pulse labeled with 5-bromo-2'-deoxyuridine (BrdUrd) and double-stained with a fluoresceinated monoclonal antibody to BrdUrd and with propidium iodide (PI). In initial experiments, melanoma cells were first pulse labeled with BrdUrd, treated with prostaglandin E1 (PGE1 10 micrograms/m1) or vehicle (0.1% ethanol) for up to 24 hours, then stained with anti-BrdUrd and PI. PGE1-treated cells monitored at 3-hour intervals were observed to migrate from S phase to G2 phase, then, enigmatically, back into the late S phase region of the distribution. In other experiments, cells treated with PGE1 were pulse labeled with BrdUrd at the end of the treatment period and harvested. In these experiments, there was a small, discrete subpopulation of cells within the late S phase region of the DNA distribution that was negative for anti-BrdUrd. This subpopulation of cells was sorted and examined by light microscopy. We observed that 95% of these BrdUrd-negative "S phase" cells were mitotic cells. Since mitotic cells and G2 cells have equivalent amounts of DNA, the reduced red fluorescence exhibited by these cells may be due to a greater sensitivity to denaturation, which has been described for DNA of mitotic cells, and would account for the phenomenon of cells appearing to move "backwards" in the cell cycle. This report indicates that although the BrdUrd/PI method can further define the cell cycle into four compartments, it can also lead to over-estimation of S phase cells in kinetic studies because of contaminating mitotic cells.     

Effect of intraarterial somatostatin infusion on SMA blood flow

Experiments were carried out on anaesthetized cats to study the effect of somatostatin on the mesenteric circulation. Intraarterial infusions of somatostatin were applied into the superior mesenteric artery. The effect of atropine, propranolol and phentolamine were investigated. Catecholamine release or uptake of the mesenteric vascular bed during somatostatin infusions were also measured. We found dose dependent vasodilatory effect of somatostatin on the mesenteric vasculature that was not influenced by atropine and by the adrenoreceptors or by denervation. A direct effect of somatostatin on the vascular smooth muscle membrane is assumed.     

Changes in the morphology of Ehrlich ascites tumour cells caused by hyperosmotic media

It was found that Ehrlich ascites tumour cells undergo significant morphology changes in media in which osmolarity is increased by NaCl or Hanks' balanced salt solution. The morphology changes include formation of filopodia- and lamellipodia-like cell surface protrusions. Their formation is enhanced by an addition of cytochalasin B. The data obtained suggest that both changes in plasma membrane properties and changes in activity of contractile apparatus participate in the formation of cell surface protrusions.     

Sweat glands of the scrotum of the bull

Skin samples were taken post mortem from the scrotum, abdomen and neck of 4 mature bulls. The volume of sweat glands per unit skin surface area of the scrotum was greater than that of other body regions. Within the scrotum there was a gradient in sweat gland volume increasing from proximal through to distal parts of the scrotum. These results suggest a previously unidentified variable cooling capacity of the scrotum depending on testicular descent.     

Platelet-activating factor in the rabbit uterus during early pregnancy

Platelet-activating factor (PAF) concentrations were low in the non-pregnant, oestrous uterus (mean +/- s.e.m.: 2.2 +/- 1.2 pmol/g, n = 3). However, uterine PAF increased dramatically during pregnancy to a maximum of 37.8 +/- 4.90 pmol/g (n = 7) on Day 5. By Day 7, PAF concentrations in the uteri of pregnant rabbits had returned to levels similar to those found at oestrus. In contrast, uterine PAF in pseudopregnant rabbits peaked at 30.6 +/- 2.8 pmol/g (n = 8) on Day 4, declined to 20.5 +/- 2.4 pmol/g (n = 8) on Day 5 and then remained at that concentration through Day 7. Uterine PAF co-migrated with synthetic PAF (1-O-hexadecyl-2-acetyl-sn-glycero-phosphocholine) in both thin-layer and normal-phase high-performance liquid chromatography. PAF activity in the uterus during pregnancy and pseudopregnancy was found almost exclusively in the endometrium; little or no PAF was found in myometrium, uterine flushings or blastocysts. While no PAF was detected in blastocysts on Days 5 and 6 of pregnancy, the presence of the embryo appears to modulate biosynthesis and/or degradation of PAF by the uterus, since PAF decreased significantly in uterine tissue apposed to the implanting embryo (but not in similar areas between such attachment sites). Increased concentrations of PAF in the preimplantation rabbit uterus followed by a dramatic decrease on the day of blastocyst attachment suggest that this potent inflammatory autacoid may play a vital role in implantation.     

The apparent reversal of a wasting syndrome by nutritional intervention in Saguinus mystax

One hundred eighty sexually mature Saguinus mystax were imported from Peru in six lots over a period of 1 year. Within 1 year after arrival, the mortality was 60% and the majority of the tamarins showed signs similar to "wasting marmoset syndrome" (WMS). In an effort to improve the survival rate, an open formula diet replaced the commercial closed formula diet that had been fed since arrival of the tamarins. The open formula diet contained 26.2% crude protein, 12.3% ether extract, 43.3% nitrogen free extract and 5.9% crude fiber on a dry matter basis. The diet was evaluated on the basis of palatability, weight gain, mortality, digestibility, nitrogen balance, serum biochemical parameters and blood counts. The mean daily consumption on an as-is basis was 44.8g or 335 Kcal gross energy/Kg of body wt./day. During the 3 month open formula diet evaluation period average weight increased by 56g (p less than .05), mortality decreased demonstratively, and alopecia and chronic diarrhea were nearly eliminated. Mean daily gross energy intake for S. mystax (335 Kcal/Kg of body wt/day) was substantially greater than previously reported values for callitrichids. WMS signs observed in the S. mystax colony were controlled by providing what appears to be an adequate diet.     

Serodiagnosis of Streptococcus pneumoniae infection in guinea pigs by an enzyme-linked immunosorbent assay

Guineapig antibodies to Streptococcus pneumoniae (SPN) serotype 19F were detected by an enzyme-linked immunosorbent assay using a simple procedure. In experimentally infected hosts, antibody was detectable as early as 2 to 3 weeks after infection, and high titres were maintained for a long period. Antibodies higher than 1:64 were regarded as specific. In a field study, high antibody titres were shown in SPN enzootic colonies in contrast to negative or low antibody titres in a majority of the animals from non-enzootic and SPF colonies.