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Biomedical subjects

E Miller

Publications and source records attributed to E Miller.

At least 19 recordsLinked to original sources

Mechanisms of Hexavalent Chromium-Induced Reproductive Toxicity: A Focus on the Ovary and Placenta.

Hexavalent Chromium (Cr(VI)) is a Group A carcinogen, mutagen, and teratogen. Cr(VI) has been used by more than 50 industries, and its contamination of drinking water is widespread across the United States (U.S.). Epidemiological data of women who lived in Willits, California, U.S., indicate that environmental exposure to Cr(VI) adversely affects pregnancy outcomes and the health of their immediate offspring, resulting in a low birth rate, pregnancy loss, and spontaneous abortion, and their children (F1 offspring) experienced birth defects. However, the molecular mechanisms behind Cr(VI)-induced reproductive and developmental toxicity are poorly understood. Cr(VI) enters cells through anion transporters and is rapidly reduced to Cr(III) by endogenous antioxidants within the cell. Cr(III) forms adducts with DNA, which can block DNA replication and transcription; abnormal repair can lead to DNA double-strand breaks, mutations, micronucleus formation, chromosomal abnormalities, and increased genomic instability. Cr(VI) induces oxidative stress via the Fenton reaction, generating free radicals, and depleting antioxidants, thereby promoting apoptosis via p53-dependent and independent pathways, resulting in follicular atresia and accelerated reproductive aging. Antioxidant supplementation with resveratrol, vitamin C, and edaravone mitigates Cr(VI) toxicity in the ovary. Cr(VI) disrupts meiosis in metaphase II oocytes by causing DNA strand breaks, altering F-actin dynamics, disturbing microtubules, and leading to chromosome missegregation. Gestational exposure to Cr(VI) also disrupts placental function through multiple mechanisms by targeting trophoblast lineages. The current review focuses on genotoxicity, oxidative stress, and other mechanisms by which Cr(VI) disrupts the female reproductive and endocrine systems, with particular emphasis on the ovary and placenta.

Hexavalent chromium

Prenatal and early postnatal beta-adrenergic receptor-mediated increase of cyclic AMP in slices of rat brain.

The levels of cyclic AMP in slices of cerebral cortex and cerebellum from newborn rats were significantly, but transiently, increased by exposure to the beta-adrenergic agonist, isoproterenol. Isobutylmethyxanthine, an inhibitor of phosphodiesterase, enhanced this effect and permitted its detection in cerebral cortex obtained from the prenatal rat. These results are consistent with the possibilities that functional noradrenergic synapses are formed early in the ontogeny of the CNS, and that norepinephrine may exert cyclic AMP-mediated influences on brain development.

1-Methyl-3-isobutylxanthine

Filtration characteristics of the polyester fiber micropore blood transfusion filter.

The filtration characteristics of a new polyester fiber (Fenwal II) micropore blood transfusion filter were investigated. Filtration of stored human whole blood and packed cells resulted in return of screen filtration pressure (SFP) of the blood to normal. Increased filter weights verified removal of large amounts of debris and microaggregates from the blood. Filtration of large quantities of blood accomplished at very high flow rates did not adversely affect the composition of the filtered blood. We conclude that the polyester fiber (Fenwal II) micropore blood transfusion filter is effective in removing microaggregates from stored whole blood and packed cells. It has a high volume capacity, allows rapid flow, and is reliable during pressure transfusion.

Blood Banks

The long-term consequences of head injury: a discussion of the evidence with special reference to the preparation of legal reports.

An outline is presented of the longer term consequences of severe closed head injury (i.e. those exceeding the period of PTA). It is shown that head injury can have very serious consequences for the victim. Despite the fact that measures of IQ have been claimed to show considerable recovery it is likely that severe head injury invariably results in some degree of permanent functional impairment. The vexatious issue of the 'post-concussional syndrome' is discussed and the conclusion is reached that it is unlikely that this syndrome is solely produced by the possibility of compensation.

Amnesia

Quality of life for long-term survivors of end-stage renal disease.

Eighteen children and adolescents who survived two years or longer in an attempt to manage their end-stage renal failure by transplantation were studied. The psychological adaptation of the young person to this form of management of renal disease was assessed by a semistructured interview of the patient and his parents. Fifty percent of the patients functioned at school or on the job and did not have depression. The remaining half did less well. In our institution a satisfactory quality of life required a successful transplant.

Adaptation, Psychological

Silicone prostheses and anti-tumor immunity: an in-vitro rat study.

We believe we have demonstrated that there is no difference in the immune responsiveness in normal animals which undergo sham surgery (as compared to those unoperated). With the addition of a simple placement of a silicone prosthesis, there was an increase in the lymphocyte cytotoxicity--but this was equalized by a blocking effect at both the target cell and the lymphocyte levels. This response appeared to be of short duration. The presence of tumor, as previously documented produces an increase in lymphocyte cytotoxicity with a concomitant increase in the target cell and the lymphocyte blocking effect. Importantly, we found no significant difference in the immune response when prostheses were placed as an adjunct to surgical excision of transplanted tumors in this rat model.

Animals

Retrieval from long-term memory in presenile dementia:two tests of an hypothesis.

Recent experimental studies have suggested that patients with presenile dementia might have diffculty in retrieving information from memory as well as a reduced ability to acquire new information. The hypothesis that this retrieval difficulty might be due to an inability to inhibit the recall of irrelevant information was tested by two investigations. Free recall data failed to give clear support for the hypothesis but a prediction based upon recognition testing was confirmed.

Dementia

Maturation of the visual evoked response in newborn miniature pigs.

As a prelude to neurobehavioral toxicologic studies in neonatal minipigs, normal maturational changes in the visual evoked response (VER) were determined in 6 Hormel-bred minipigs. The VER were highly variable for the 1st several days of life, but were reasonably stable by the 2nd weeks. All adult waveform components were present at birth, and maturational changes primarily affected waveform latency and consistency. Only one waveform (Pi) was sufficiently distinct and consistent for statistical evaluation. At birth the latency to Pi was about 102 ms. The latency of Pi rapidly decreased to about 56 ms during the next 25 days, and subsequent changes were minimal. Comparison with other species indicates many cross-species relationships of specific VER components, with the minipig VER having many maturational and topographic similarities to the human VER.

Animals

Preliminary report of the distribution of [14C]penicillic acid in rats: autoradiographic technique.

The distribution of [14C]penicillic acid in rats was determined by autoradiographic technique. Adult male rats were given [14C]penicillic acid orally and IV. According to autoradiographic analyses 24 hours later, high levels of radioactivity were in liver, heart, kidneys, lungs, and caudal part of the intestine. The significance of bile as an excretory route for penicillic acid was confirmed by the results from IV administration of the compound.

Administration, Oral

Polyurethane foam (Bentley) micropore blood transfusion filter: filtration characteristics.

Stored human blood of varying age was passed through polyurethane foam (Bentley) micropore blood transfusion filters. Passage through these filters resulted in decreased screen filtration pressure (SFP) of the blood and increased filter weights. Numerous microaggregates were removed and SFP returned to normal after filtration. Occlusion of the filter occurred after passage of only 2 units of whole blood. On the basis of this research, we conclude that polyurethane foam (Bentley) micropore blood transfusion filters are effective in removal of microaggregates from stored human blood. Because the filtering capacity is not great, it is recommended that when these filters are used during transfusion a new filter be used for each unit of blood administered.

Blood Preservation

Carcinogenicity of fibrous glass: pleural response in the rat in relation to fiber dimension.

Seventeen fibrous glasses of diverse type or dimensional distribution induced different incidences of malignant mesenchymal neoplasms when implanted in the pleurae of female Osborne-Mendel rats for periods of more than 1 year. Neoplastic response correlated well with the dimensional distribution of fibers. Fibers less than or equal to 1.5 mu in diameter and greater than 8 mu in length yielded the highest probability of pleural sarcomas, and probability trends suggested that pleural sarcoma incidence increased with increasing lengths of fibers with diameters of less than 1.5 mu, Morphologic observations indicated that fibers less than or equal to 8 mu in length were inactivated by phagocytosis. In fibers greater than 8 mu in length, the correlation of carcinogenicity witth increasing length was difficult to explain. Since neoplastic response to a variety of types of durable fibers, particularly asbestos fibers, was similar, our experiments reinforce the idea that the carcinogenicity of fibers depends on dimension and durability rather than physicochemical properties and emphasize that all respirable fibers be viewed with caution.

Animals

The management of dementia: a review of some possibilities.

Evidence relating to the effects of therapeutic intervention on the behaviour of elderly demented patients is reviewed. Contrary to common prejudice there is strong evidence that improvements in functioning can be achieved by social and behavioural manipulations although maintaining such gains may be more difficult. There are some indications as to what type of intervention is likely to be most effective and some specific techniques that might be of use are discussed.

Attitude of Health Personnel