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Biomedical subjects

J J Christian

Publications and source records attributed to J J Christian.

At least 19 recordsLinked to original sources
PubMed2000

Female house mice develop a unique ovarian lesion in colonies that are at maximum population density.

Colonies of house mice reach maximum population density in 120-180 days, irrespective of cage size and initial number of colonizing animals. Reproduction ceases because the females become aggressive and unreceptive to mating. The aggressive behavior is correlated with elevated levels of testosterone (T) and corticosterone (B) (Chapman et al., Phys Behav 64:529-533, 1998). In two of seven strains of mice, females developed ovarian lesions. The occurrence of the lesion in one strain was correlated with the age of the animal and duration of the study. In the second strain, cage size was the determining factor. Lesioned ovaries weighed significantly more than nonlesioned ovaries. The lesion consisted of accumulations of luteal membrane and organelle fragments, and other cellular debris, suggestive of incomplete and prolonged luteolysis. Electron microscopic (EM) analyses revealed the presence of deposits of permanganate-resistant congophilic amyloid fibrils in the intima and smooth muscle cells of luteal thecal arteries. Population females had thymus glands and uteri that weighed significantly less than the same organs from females housed in the breeding colony, whereas the adrenal glands from the population females weighed significantly more. It is proposed that the female aggression is due to high levels of T. It is also proposed that the high levels of B suppress the immune cells involved in normal luteolysis and contribute to the incomplete and prolonged luteolysis.

Aggression↗
PubMed1998

Analysis of steroid hormone levels in female mice at high population density.

Populations of predominantly female house mice (Mus musculus) were created by placing virgin female mice in cages (0.045 m2 to 0.48 m2) with a single stud male, and removing all ensuing male offspring at weaning. At maximum population size, the females in these all-female/one-male populations exhibited male-like aggressive behavior. Termination of the populations and subsequent measurement of steroid hormone levels indicated that the aggressive females had high circulating level of testosterone and corticosterone, and elevated baseline levels of progesterone. The high levels of corticosterone could be lowered by dexamethasone, but not the high levels of testosterone.

Aggression↗
PubMed1983

An ACTH-induced renal glomerular lesion in the mouse: immunofluorescence microscopy.

Mice were injected with adrenocorticotropic hormone (ACTH) and the glomerular lesion that was induced was studied by light and immunofluorescence microscopy. By light microscopy, kidneys from ACTH-treated mice showed typical ACTH-induced glomerular lesions. Immunofluorescence of kidneys from ACTH-treated mice revealed intense staining for IgG and IgM in the extraglomerular mesangium (EGM), in Bowman's space, and in the ascending thick limb of Henle near the macula densa. Staining for immunoglobulins was unchanged after treatment with acid buffer. Immunoreactivity for complement (C3) was confined largely to the EGM and Bowman's space. Staining for albumin was almost exclusively in Bowman's space or the peripheral glomerular tuft in discrete aggregates. The above patterns of IgG, IgM, C3 and albumin were seen in control mice, although much less frequently. The results show that in mice, treatment with ACTH results in the increased accumulation of plasma proteins in the juxtaglomerular apparatus (JGA). This effect may reflect a role for the JGA in the normal clearing of plasma proteins from the glomerulus and/or directly from the blood.

Adrenocorticotropic Hormone↗
PubMed1981

The development of an acth-induced renal glomerular lesion in Mus musculus. An ultrastructural study.

Male house mice (Mus musculus) were injected with 4 international units of ACTH daily for 1, 2, 3 and 4 weeks and with four units daily for four weeks followed by 8 units for 8 days. Light microscopy of kidneys showed a glomerular lesion characterised by the expansion of the mesangium, deposition of PAS positive material in the glomerular mesangium and extraglomerular mesangium hypertrophy of juxtaglomerular cells and a successive increase in oil red-O staining material in the glomerulus. Electron microscopy revealed the progressive accumulation in the mesangial matrix of three morphologically distinct forms of deposits: amorphous, globular and particulate. The accumulation of amorphous deposit apparently is partially responsible for the increased PAS positive staining of the mesangium. Globular (and possibly particulate) deposit probably corresponds to the oil red-O positive material. The evidence suggests that the deposits are extraglomerular in origin, but their chemical nature is unknown.

Adrenocorticotropic Hormone↗
PubMed1979

Perinatal naloxone: when does naloxone affect hyperalgesia?

Pregnant mice were treated with naloxone via subcutaneous implants, from about 5 days prior to parturition. At birth entire litters were cross-fostered so that groups of offspring were exposed to naloxone treated mothers; before birth, after birth to weaning, from about 5 days prior to birth to weaning, or not exposed to naloxone. When tested on a hot-plate at 50 days of age, females either prenatally treated or treated pre- and postnatally showed hyperalgesia to heat. For males, this effect was not evident. This sex difference may have been induced by the cross-fostering procedure.

Aging↗
PubMed1978

Estrous cycle regulation in the whitefooted mouse (Peromyscus leucopus) with special reference to vaginal cast formation.

The estrous cycle of the whitefooted mouse (Peromyscus leucopus) was consistent with those described for most small rodents and closely resembled that of the house mouse and the rat in timing. The presence of the male did not accelerate puberty nor induce cycle synchrony, but was critical in establishing cycle regularity. Females isolated from influences of males never attained a pattern of concistent cycle length. Development of the vaginal epithelium during estrus was excessive in both isolated and non-isolated females, resulting in a "cast" of cornified epithelium which could be removed intact during metestrus. Casts removed during the making of vaginal smears measured up to 20 mm in length and still left a sufficient residue of cells which could be detected in all stages of the estrous cycle.

Animals↗