Porcine toxoplasmosis in Indiana

Toxoplasmosis was diagnosed at necropsy in a 4-week-old pig from a litter of 16 born to a clinically normal sow. Multifocal acute necrosis of blood vessels and parenchyma was found in the small intestine, mesenteric lymph nodes, liver, lungs, and brain. Numerous tachyzoites, ultrastructurally indistinguishable from Toxoplasma gondii, were found in lesions. The affected pig and seven other littermates died after diarrhea had developed within 1 to 2 weeks of birth. The most likely source of infection was oocysts from cats on the farm.

Lipofuscin accumulation in squirrel monkey spinal cord consequent to protein malnutrition during gestation

The formation of lipofuscin pigment in the anterior horn cells of the cervical spinal cord has shown in the fetuses and neonates under the extrinsic influence of maternal protein deprivation during the gestation period in the squirrel monkeys.

Nucleolar activity in the primate dorsal root ganglion cells associated with dietary protein malnutrition

The nucleolar changes in the dorsal root ganglion cells of the squirrel monkey, Saimiri sciureus, have been investigated by the use of histological and histochemical methods in the healthy neonates (born to mothers maintained on 25% protein diet during gestation) and young adults, and compared with those observed in the protein-malnourished neonates (born to mothers maintained on a 8% protein diet during gestation). Also studied were young adults maintained on a high protein diet (25% protein) as well as on a low protein diet (2% protein content) for a period of 15 weeks. Whereas in the healthy animals (neonates and young adults) only a few cells show nucleolar budding and finally their extrusion into the cytoplasm, the protein-malnourished animals show a significantly enhanced nucleolar activity in the form of increased size (3-4 times the original) and active budding either from one focal point or at several places on the body of the nucleolus. In the neurons which show chromatolytic changes, these extrusions migrate to the nuclear membrane, wherefrom they pass on to the cytoplasm through an evagination of the nuclear envelope. Such a migration appears to occur by a focal dissolution of the nuclear membrane. It appears that, under conditions of severe malnutrition and advanced chromatolytic changes in the neuronal cytoplasm, the nucleolar material provides a compensatory mechanism for the increased cytoplasmic catabolism and loss of ribonucleoprotein material in order to facilitate additional protein synthesis for cell survival.

Experimental protein malnutrition in squirrel monkeys: cytochemical interaction of nucleolus and cytoplasm in the anterior horn cells of the spinal cord of Saimiri sciureus

Nuecleolo-cytoplasmic relationships have been studied using histochemical techniques in the spinal cord of healthy neonates compared with those born to mothers malnourished through most of the gestation period, and healthy and severely protein-malnourished young adult squirrel monkeys. Formaldehyde-fixed as well as fresh frozen tissues were used for histological study and for histochemical techniques to demonstrate lipids, carbohydrates, nucleic acids and enzymes of various metabolic cycles. Changes in the neuronal cytoplasm of the low protein animals appear to be related to impaired protein metabolism and energy transport. The nucleolus reacts to cytoplasmic changes by enlarging its size and by active synthesis of secretion of nucleolar material, which is then passed into the cytoplasm through an evagination of the nuclear envelope. The greater the degree of chromatolysis in the cytoplasm, the more active the nucleolus appears to be in terms of its enlarged size and transfer of secretion products into the cytoplasm. It is believed that the perinuclear accumulation of secretion products in the neuronal cytoplasm of the protein-deficient animals has its origin in the nucleolus. Such an accumulation in the severely malnourished animals appears to be a compensatory mechanism for the increased cytoplasmic catabolism and loss of ribonucleoprotein material in order to facilitate additional protein synthesis for cell survival.

Reversibility of lipofuscin accumulation caused by protein malnutrition in the motor cortex of squirrel monkeys, Saimiri scireus

Lipofuscin pigment has been demonstrated histochemically in the motor cortex by the use of several histochemical and cytochemical methods in the healthy (maintained on a diet with 25% protein content) and protein malnourished (maintained on a diet with 2% protein content) adult animals. 4 animals in the latter category were rehabilitated over a period of 11 months and various histochemical techniques were repeated on the motor cortex of these animals. The healthy animals showed a somewhat uniform distribution of lipofuscin pigment in the neuronal perikarya with the perineuronal glia showing only slight occurrence of pigment bodies. The malnourished animals exhibited a significantly larger number of lipofuscin bodies in the neuronal as well as glial perikarya. The neurons, especially, showed aggregations of lipofuscin bodies characterized by a large increase in the activity of acid phosphatase and simple esterases. The rehabilitated animals, however, showed a decrease of lipofuscin pigment in the neuronal perikarya with a concomitant loss of lysosomal enzymes, while a significant increase of these bodies was observed in the perineuronal glial cells. It is evident that the formation of lipofuscin pigment gets accelerated under the extrinsic influence of dietary protein deprivation in the adult animals, but the process is reversed at least to some extent by halting the dietary deficiency or its correction by rehabilitation. The perineuronal glial cells appear to play a significant role in the removal of lipofuscin bodies from the neuronal perikarya. The significance of these observations has been discussed.

Lipofuscin formation in the developing nervous system of squirrel monkeys consequent to maternal dietary protein deficiency during gestation

The formation of lipofuscin pigment under the extrinsic influence of maternal protein deprivation during most of the gestation period has been demonstrated in the cerebellum and motor cortex of the developing fetuses and neonates in squirrel monkeys. The controls maintained on high protein diets failed to show lipofuscin pigment in appreciable quantities. The dirty yellow to dark brown pigment bodies exist as homogeneous particulates as well as duplex structures, each with a thin, irregular, light brown cortex, studded with one or more darker granules, and a medulla filled with sharp yellow substance. The malnourished neonates, especially in the third and fifth laminae of motor cortex, show loose aggregations of lipofuscin bodies in the apical dendrite and occasionally in the body of the dendritic branches but not in the axon hillock or the body of the axon. Histochemically, the pigment is a complex of lipids, carbohydrates and proteins, showing strong reaction for non-specific esterase and acid phosphatase and mild activity of succinate and lactate dehydrogenase and monoamine oxidase, which puts the pigment observed in the same category as the typical aging pigment described in literature. It is clear that maternal protein deficiency during the critical period of the fetal brain development has an adverse effect on its biochemical maturation. The accumulation of lipofuscin pigment is probably one manifestation of the metabolic changes in the neurons, which may have the impact of hastening the aging process, if protein deprivation is continued into the postnatal period.

Pyridine as an unmasking reagent for lipoprotein complexes in the nervous system of protein deficient squirrel monkeys

Acid hematin test with pyridine and Sudan black B controls was employed on selected areas of the brains of 115, 140 days fetuses, neonates and adult squirrel monkeys maintained on low and high protein diet. Our histochemical findings indicate that the reduction of phospholipids in the low protein fetuses and neonates is related to myelination, wereas in the adults, most of the lipids are bound to proteins and/or cerebrosides to form complexes, as revealed by the unmasking action of pyridine.