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Biomedical subjects

J A Sechzer

Publications and source records attributed to J A Sechzer.

17 recordsLinked to original sources
PubMed1986

Stable isotopes of lithium: dissimilar biochemical and behavioral effects.

Lithium, which is used routinely in the treatment of mania, is composed of two stable isotopes, lithium-7 (92.58%) and lithium-6 (7.42%). Usually there is minimal physiological or biochemical differentiation between isotopes of an element, but lithium is an exception. Data derived from a variety of biochemical and behavioral experiments are reviewed to support this idea. Additionally, the clinical implications of this work are presented.

Animals↗
PubMed1986

Aberrant parenting and delayed offspring development in rats exposed to lithium.

Natural lithium (Li) salts, including those used routinely in manic depressive illness, consist of two stable nonradioactive isotopes: lithium-7 (Li-7) (92.6%) and lithium-6 (Li-6) (7.4%). Female rats (3 months old) were treated with either Li-7 chloride or Li-6 chloride or were untreated prior to and during gestation and lactation. Birth weights were lower for Li-treated animals than for normal pups. Maternal behavior of all Li-treated mothers was altered. Li-7 mothers ignored their pups and nursed them infrequently. Li-6 mothers groomed and nursed their pups more often than normal mothers. All pups showed delays in development, especially in the maturation of depth perception. Although Li-6-treated dams were over-protective mothers, their offspring showed longer developmental delays than those of Li-7-treated offspring.

Animals↗
PubMed1984

Development and maturation of postural reflexes in normal kittens.

In order to evaluate neurologic development, postural reflexes were tested in normal kittens from birth through 7 weeks of age until stable adult patterns of performance were attained. These reflex tests included: body and air righting, visual placing, chin placing, tactile placing, hopping, and locomotion. A protocol for scoring responses was designed for each individual reflex to differentiate their progression. The first reflexes to mature were visual placing, chin placing, and body righting which attained a maximal score during the 3rd week of life. This was followed by maturation of the forelimb hopping reflex and independent locomotion during the 4th week. Forelimb tactile placing responses, hind limb hopping reflexes, and air righting developed by the 5th week. Hind limb tactile placing responses were the last to mature. They became fully expressed in the 6th week. The pattern of ontogeny of these reflexes proceeded in a cephalocaudal direction. This is in agreement with earlier observations of others who correlated the maturation of reflex responses in kittens with myelination in the central nervous system.

Aging↗
PubMed1976

The split-brain neonate: a surgical method for corpus callosum section in newborn kittens.

One way to determine the importance of interhemispheric interaction in the development of adaptive and acquired behavior is to section completely the corpus callosum about the time of birth before myelination commences and before any significant hemispheric interaction takes place. Therefore, we developed a technique for commissurotomy in the neonatal kitten 36 to 72 hr of age. A specially designed "commissurotomy knife" was used which eliminated retraction of the hemispheres. Histology showed completeness of corpus callosum section as well as commissure of the fornix without any apparent damage to cortical or subcortical structures. This technique meets the following criteria: (1) reproducibility or lesions without additional nonspecific damage; (2)minimal exposure and manipulation of the delicate newborn brain: (3) brief operational procedure minimizing risk of infection; and (4) low mortality rate.

Anesthetics↗
PubMed1971

Development behaviors: delayed appearance in monkeys asphyxiated at birth.

Developmental behaviors were studied in monkeys subjected to asphyxia at birth. Visual depth perception, visual pla ing, and locomotion appeared significantly later than in nonasphyxiated monkeys. After these behaviors had been established in asphyxiates, however, there was little difference from those observed in normal monkeys. These results were compared with reports of permanent learning deficits that occur in monkeys asphyxiated at birth for similar periods of time. Such comparison suggests that the neural structures responsible for the developmental behaviors studied are not damaged by asphyxia to the same extent as those for acquisition. Delay in development may be an early indication of brain damage with subsequent mental retardation.

Amnesia↗
PubMed1970

Prolonged learning and split-brain cats.

A definite relation is shown between interhemispheric transfer and speed of learning. Split-brain cats were trained in a variety of discriminations, and the success or failure of interhemispheric transfer was evaluated with regard to rate of learning. When interhemispheric transfer succeeds, learning time is normal; when interhemispheric transfer fails, learning time is prolonged, becoming at least twice that of normal. Retention is also poor in those animals that exhibit prolonged learning. A normal learning curve appears to be the product of interaction between both cerebral hemispheres during learning.

Animals↗