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Biomedical subjects

C L Chrisman

Publications and source records attributed to C L Chrisman.

At least 37 records · Page 2Linked to original sources
PubMed1988

Analysis of post-implantation mouse embryos after maternal heat stress during meiotic maturation.

The effects of heat stress during oocyte maturation were studied in post-implantation mouse embryos. Virgin ICR mice were exposed to 35 +/- 1 degree C and 65 +/- 3% RH for 12.5 h beginning immediately after synchronization of ovulation with PMSG and hCG. Embryos of heat-stressed dams were developmentally heterogeneous and showed significant delays in development with as much as 48 h delayed development. Nearly 6% of these embryos were triploid, and another 2% were hyper-diploid. Development of triploid embryos was delayed more than 24 h. Nine embryos with severe developmental delay had heterogeneous chromosome constitutions. Embryo mortality before and after implantation was higher in heat-stressed dams than in controls.

Animals↗
PubMed1986

Effects of dexamethasone and chlorpromazine treatment on X-Y dissociation and multinucleated giant cell formation in hyperthermic mice.

The effects of anti-stress drugs on X-Y dissociation and multinucleated giant cell formation in the testes of hyperthermic mice were determined for the possible use of such drugs in animal production. Mice were injected with dexamethasone 1 mg/kg or 2 mg/kg, chlorpromazine 1 mg/kg or 4 mg/kg, or 0.85% saline, and heat stressed for 4 d at 35 +/- 1 C and 65 +/- 1 % relative humidity. Mice were killed 5 d after stress, and the testes processed for observation of meiotic chromosomes and testicular histology. Heat stress caused a significant increase in X-Y bivalent dissociation in diakinesis-metaphase I spermatocytes and a significant increase in formation of multinucleated giant cells. Drug treatment increased X-Y dissociation but had no significant effect on giant cell formation.

Journal Article↗
PubMed1984

Neuroaxonal dystrophy of Rottweiler dogs.

Five Rottweiler dogs were examined because of progressive ataxia of thoracic and pelvic limbs of several months' to 4 years' duration. Hypermetria, especially of the thoracic limbs, and head incoordination and tremors were obvious features in the 3 older dogs. None of the dogs had evidence of weakness or loss of conscious proprioception. An electroencephalogram in 1 severely affected dog was normal. Electromyograms in 2 severely affected dogs were normal except for some positive sharp waves and fibrillation potentials in the interosseus muscles of all 4 feet. Cerebrospinal fluid evaluations of 2 severely affected dogs were normal. A reduced number of sensory nerve endings, compared with age-matched controls, was seen on histologic examination of a conjunctival biopsy specimen in 1 severely affected dog. An antemortem diagnosis of neuroaxonal dystrophy was suspected from the signalment, history, and neurologic examination findings. The diagnosis was confirmed on the basis of microscopic findings in 3 dogs necropsied.

Animals↗
PubMed1984

A leukoencephalomyelopathy of rottweiler dogs.

Two adult rottweiler dogs were evaluated for slowly progressive ataxia and paresis of all four limbs of over seven months duration. On neurologic examination, signs referable to a lesion in the cervical spinal cord affecting motor and sensory white matter tracts were found. Both dogs were necropsied and were found to have demyelinating lesions in the spinal cord, brain stem, and deep cerebellar white matter. Primary morphologic alterations were intact naked axons and thinly myelinated axons accompanied by reactive astrogliosis. The spinal cord lesions tended to have bilateral symmetry and were found in the lateral funiculi and occasionally in the dorsal funiculi. The cause and pathogenesis of the lesion were not determined.

Animals↗
PubMed1982

Neurotoxicologic effects of the nonionic contrast agent iopamidol on the leptomeninges of the dog.

The effect of iopamidol on the leptomeninges was tested and compared with that of metrizamide and normal saline solution in 18 dogs. Pathologic and clinical effects were evaluated at 24 hours and 14 days after cisternal injection of iopamidol, metrizamide, or normal saline solution. Pathologic changes were evaluated by microscopic examination of serial CSF samples and of sections of brain and spinal cord with the leptomeninges intact. Clinical changes were subjectively evaluated. Electromyograms and EEG were performed on each dog after physical and neurologic examination. There were no changes seen in neurologic status, electromyogram, or EEG in any of the dogs immediately after subarachnoid injection nor at 24 hours or 14 days later. Pathologic changes were limited to mild, moderate, or severe patchy hemorrhagic leptomeningitis seen at 24 hours after iopamidol or metrizamide was injected. The severity of changes were judged to be similar with both these agents. The CSF analysis and histologic evaluation of brain and spinal cord sections revealed a neutrophilic response to iopamidol and a mononuclear response to metrizamide. These findings indicate that iopamidol has minimal neurotoxicologic effect on the leptomeninges and therefore has merit as a myelographic agent.

Animals↗
PubMed1981

Ovum morphology after hyperthermic stress during meiotic maturation and ovulation in the mouse.

Eggs were collected from 60 virgin ICR mice 15 1/2 h after synchronization of ovulation with PMSG and hCG from control females and those exposed for 15 1/2 h to hyperthermic conditions (35 +/- 1 degrees C, 65 +/- 3% relative humidity) immediately after the hCG injection. Eggs were classified for analysis as monocellular, bicellular, tricellular equal, tricellular, unequal, multicellular and degenerate. Egg class frequencies were affected by increasing atypical forms (P < 0.01). Stressed animals had significantly larger cells when an analysis of variance was performed on the bicellular classification, but there was no effect on ovum diameter.

Animals↗
PubMed1981

Influence of phenylalanine and lysine deficiencies on thyroid morphology in the chick.

A study was conducted to investigate the effects of dietary phenylalanine and lysine deficiencies on thyroid morphology in chicks fed crystalline amino acid diets. Both mean follicle diameter and epithelial cell height were significantly reduced in birds fed either of the deficient diets as compared with controls. These results agree with previous studies on serum T4 and T3 concentrations where the effects of an amino acid deficiency were general and not limited to precursors of thyroxine.

Animals↗
PubMed1981

Cytogenic analysis of preimplantation blastocysts from prepuberal gilts treated with gonadotropins.

Metaphase chromosomes were examined in 10-day-old embryos collected from prepuberal gilts that had been induced to ovulate, using a combination of 200 IU of human chorionic gonadotropin (HCG) and 400, 600, or 800 IU of pregnant mare serum gonadotropin (PMSG) followed 72 hours later by 500 IU of HCG. A repeatable, reliable method was developed for the processing of early porcine embryos in the hatched spherical blastocyst stage for cytogenetic analysis. Of 170 embryos recovered and processed from 21 gilts, 169 yielded analyzable metaphase cells for determination of somatic cell chromosome number for an overall success rate of 99.4%. All embryos were diploid (2n = 38) in chromosomal constitution, and although isolated tetraploid (4n = 76) and octaploid (8n = 152) cells were found, true triploid or other polyploid embryos were not present. The absence of these aberrations indicated that at the dosage levels tested, the hormone PMSG did not cause an increase in occurrence of polyploidy in porcine blastocysts present at day 10 of gestation. Analyses showed no significant (P less than 0.05) increase in numbers of corpora lutea or embryos at day 10 of gestation in gilts treated with these PMSG dosage levels.

Animals↗
PubMed1980

Hyperthermia induced dissociation of the X-Y bivalent in mice.

The mutagenic potential of hyperthermia was examined employing a spermatocyte test on males heat stressed continuously for 2, 3. or 5 days. Stress conditions were 35 +/- 1 degrees C and 65 +/- 3% relative humidity. Males were sacrificed and meiotic preparations made from the testes at various intervals following removal from the stress environment. In this way, chromosome damage could be monitored in all premeiotic and early prophase I stages of spermatogenesis. Results of this study revealed a significant increase in the incidence of X and Y univalents at metaphase I. The significance of this finding is discussed.

Animals↗
PubMed1980

Comparative karyology of the freshwater snails Bulinus tropicus and B. natalensis.

Species of the subgenus Bulinus s.s. occur in a polyploid series which is of interest because of the rarity of polyploidy in animal species and because there appears to be a relation between ploidy level and ability to transmit Schistosoma haematobium, a parasite of major public health importance. We describe a technique for the preparation of standard karyotypes using cell suspensions from colchicine-treated embryos. The results for two diploid species, B. tropicus (Krauss) and B. natalensis (Küster), are presented. Both karyotypes consist of 15 metacentric and 3 submetacentric chromosomes. However, differences in centromere position are found in four pairs of chromosomes, and in the appearance of a secondary constriction. Because B. natalensis may represent a relict taxon involved in the origin of the polyploids, the results of significance for future work on the phylogeny of this group.

Animals↗
PubMed1979

Cytogenetic effects of diethylstilbestrol-diphosphate (DES-dp) on mouse bone marrow monitored by the micronucleus test.

6 dosages of diethylstilbestrol-diphosphate (DES-dp), ranging from 0.01 to 500 mg per kg of body weight were compared to saline and phosphate buffered saline (negative controls) and two dosages of cyclophosphamide (positive control) in the micronucleus test with 115 ICR mice. DES-dp failed to generate a significant increase in micronucleated polychromatic erythrocytes over negative controls. Cyclophosphamide produced a dose-related increase in micronuclei similar to previously published reports. Iit was therefore determined that the micronucleus test did not detect the types of chromosomal changes known to be generated by DES-dp and DES.

Animals↗