Chester A. Glomski

The mongolian gerbil: qualitative and quantitative aspects of the cellular blood picture

The gerbil displays sex determined differences in packed red-cell volume, haemoglobin level, total leukocyte count and absolute number of circulating lymphocytes. The erythrocytes demonstrate a prominent polychromasia and frequent occurrence of basophilic stippling.

Mercury in the human brain.

A recently developed technique of neutron activation analysis permitted a sensitive analysis of mercury in over 160 samples of fresh brain tissue from 17 randomly selected autopsies. There was a preferential deposition of mercury in various anatomical loci. Many of these loci are those clinically or histologically affected in poisoning by methyl mercury. The greatest concentration of the metal was generally present in the cerebellum with a mean of 0.28 μMg/g (parts per million). Forty per cent of the cerebellums had concentrations greater than 0.2 ppm. The visual cortex, pons and geniculate bodies contained levels averaging 0.17 to 0.20 ppm. The lowest levels were found in the frontal lobe white matter (mean 0.07 ppm). Two brains from patients with no exceptional exposure to environmental mercury had unusually elevated levels of 1 to 2 ppm in many regions.

Erythrocyte basophilic stippling in the Mongolian gerbil

Basophilic stippling of the circulating erythrocytes is characteristic of the Mongolian gerbil. Its enzymatic digestion along with the concomitant removal of diffuse erythrocytic polychromasia by the action of ribonuclease demonstrates that it represents microscopically visible aggregates of cytoplasmic ribonucleoprotein, presumably of ribosomal origin. Up to 40% of the total circulating erythrocytes may be stippled in foetal and newborn animals. There is then a progressive decline in incidence until adult levels are attained at least by 20 weeks of age. The bone marrow of the adult gerbil contains a higher proportion of stippled red cells than the circulating blood. The stippling can be either coarse or fine and observable in both polychromatophilic and orthochromic cells. It is suggested that erythrocytes with basophilic stippling are relatively immature red cells still demonstrating remnants of cytoplasmic ribonucleoprotein.

Formation of intracellular vesicles in neonatal and adult erythrocytes: evidence against the concept of neonatal hyposplenism

ABSTRACT: Intraerythrocytic vesicles accumulate in the peripheral blood as a result of impaired clearance of these intracellular inclusions by the spleen. The observation that neonates demonstrate an increased percentage of erythrocytes containing these vesicles constitutes the primary evidence supporting the concept that the newborn is functionally hyposplenic. Neonatal erythrocytes also demonstrate an increased propensity to undergo a variety of endocytic processes. We therefore questioned whether the increase in red cell vesicles in the neonate might be the result of increased vesicle formation as opposed to impaired splenic clearance. Newborn and adult erythrocytes were incubated in vitro in synthetic medium at 37° C. Several parameters confirmed the maintenance of physiologic conditions, including levels of erythrocyte phosphate metabolites monitored by nuclear magnetic resonance. The acquisition of intraerythrocytic vesicles during the course of these incubations was compared. Over a period of 144 h, 19.2% of neonatal erythrocytes acquired vesicles compared to 3.7% of the adult cells (p < 0.001). The increase in vesicles was greater in younger density-separated erythrocytes in both the neonate (37.6%, p < 0.0005) and the adult (10.3%, p < 0.002), but persisted even in the oldest erythrocytes (12.2% and 2.4%, respectively). We conclude that the increase in erythrocytic vesicles in the neonate may not simply be an indication of hyposplenism, but a reflection of increased vesicle formation which overwhelms the clearance capability of the spleen.

The effects of low dose (less than 1 Rad) X-rays on the erythropoietic marrow

Adult female Sprague-Dawley rats were exposed (200 kvp X-rays) to whole body doses of 22-1320 mrad and examined for changes in the level of red blood cell precursors (RBCp) in the marrow at 5–30 weeks post-irradiation, under nonbled and phlebotomy-induced anemic stress conditions. Increases in the RBCp %, RBCp/mg marrow, and RBCp/skeleton under nonbled conditions, and a suppressed erythroid response to an induced anemia, were found after acute doses in the range of at least 70 mrad. Dosages of 22 or 44 mrad that induced no measurable changes when applied only once were found to be effective when they were employed 4 or 2 times/week, respectively. The results suggested the presence of a linear-quadratic dose-response relationship in which the quadratic function exists between 88 and 981 mrad, and the linear dependency, below 88 mrad.

Leucocyte alkaline phosphatase in the Mongolian gerbil and other species: a comparative view

Cytochemical analyses performed on peripheral blood smears of the Mongolian gerbil reveal the presence of variable amounts of leucocyte alkaline phosphatase (LAP) activity in the neutrophil of this species. Levels of activity in individual cells ranged from 1 to 4+. Cells completely devoid of activity were rarely encountered. Immature neutrophils residing in the bone marrow also displayed moderate amounts of enzymatic activity. The results of a semiquantitative assessment of overall LAP activity in this rodent, expressed as a mean LAP score, were compared with similar analyses carried out on a diverse sample of vertebrates. Intermediate levels of activity were recorded for the gerbil (x̄=241). This score was comparable to that obtained for the rat x̄=199) and significantly higher than that seen in man x̄=79). A wide range of LAP scores were noted for closely related species, as well as phylogenetically distant species.

Iron kinetics effects of 88 millirads

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-59T1/2 and Fe-59 RT/LT can facilitate ultra-low-dose X-ray studies involved with partial body exposures.

An effective surrogate for impact studies

Nineteen unembalmed (fresh) cadavers were used in 21 experiments to test restraint systems in automobile impact studies. Some were mounted in a rearward firing sled; others were placed in standard cars during collisions. Prior to and after testing, each cadaver was evaluated. After each experiment a postmortem examination was performed. High-speed registering cameras (1,000 to 2,000 frames per second) were used and multiple telemetric recordings were made. The radiographic and pathologic changes were similar to those seen in patients following high-velocity accidents. Results were compared with those of car accident victims admitted dead on arrival to one of our hospitals. This study is a progress report. The results are being used to improve existing restraint systems and to evaluate experimental models.

Haemolytic anaemia in rhesus monkeys induced by methylcellulose.

The rhesus monkey was evaluated in its haemopoietic and histological response to intraperitoneal injections of methylcellulose. The haematologic alterations included a mild haemolytic anaemia, lymphofaenia, monocytosis, a shortened survival of Cr51-labelled autologous erythrocytes (17·1 vs 13·3 days, P<0·025) and normoblastic hyperplasia of the bone marrow. There was a diffuse sequestration of the polymer in the phagocytic cells of the spleen, liver, bone marrow, lymph nodes and adrenal glands. The renal glomerular endothelium also consistently stored this material. Overt splenomegaly was not induced. The monkey appears to present, along with other animals, a rather species-specific response to methylcellulose that is accompanied by fundamental responses observable in all subjects.

The Mongolian gerbil (Meriones unguiculatus): its histological and haematological response to methylcellulose.

After intraperitoneal injections of 2·5% aqueous methylcellulose twice a week for 15 weeks gerbils showed a mild haemolytic anaemia, heterophnia, lymphopenia and monocytosis. Many monocytes and a few lymphocytes had a foamy vacuolated cytoplasm. There was a sequestration of methylcellulose in the phagocytic cells of the spleen, liver, bone marrow and in other scattered foci, and consistent storage in the glomerular endothelium. Myeloid metaplasia was noted in the spleen, and splenic weights were markedly increased (P < 0·05); hepatomegaly was also present. The survival at the end of 15 weeks was 60%. From this experiment, the gerbil is considered to be a potential model for a stimulated monocyte-macrophage system.