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Biomedical subjects

E Miller

Publications and source records attributed to E Miller.

At least 397 records · Page 22Linked to original sources

Inhibition of hepatitis B Dane particle DNA polymerase activity by pyrophosphate analogs.

A DNA polymerase is associated with the core of the so-called Dane particles. The probability that this is the hepatitis B viral DNA polymerase offers the possibility of preventing hepatitis B multiplication by selective inhibition of this enzyme. We have previously reported that trisodium phosphonoformate (PFA) inhibits Dane particle DNA polymerase. Fifteen compounds with structural similarity to PFA and pyrophosphate have now been tested for inhibition of hepatitis B virus DNA polymerase in an attempt to define the structural requirement for the inhibition. Active structures have two acid groups at close proximity of which at least one is a phosphono group. Phosphonoformate and hypophosphare were the two most active inhibitors. The Ki value for PFA was 7.2 microM when dTTP was used as variable substrate, and the mechanism of inhibition was non-competitive. Phosphonoformate caused rapid shut-off of the polymerase reaction, indicating that it might inhibit elongation. The efficient inhibition of hepatitis B virus DNA polymerase by PFA and its low toxicity suggest that it could be used to inhibit hepatitis B virus multiplication in vivo.

Diphosphates↗

The training characteristics of severely head-injured patients: a preliminary study.

It is argued that an important aspect of rehabilitation after severe head injury lies in training or retraining victims in skills required for independent living. Despite this, very little is known about the training characteristics of head injured patients. It is shown that in the acquisition of a psychomotor skill severely head injured subjects have very poor starting levels as compared to normal controls. They show impressive learning to the extent that they considerably close the gap between themselves and the controls. They also show appreciable transfer of the learned skill from one version of the task to another. The findings are discussed in terms of their implications for further understanding of the training process in head injured subjects in ways that could reflect upon clinical practice in rehabilitation.

Adolescent↗

Brain stem auditory evoked responses in clinical practice.

A relatively new noninvasive technique for the diagnosis of abnormalities affecting the central nervous system is presented. It is especially useful in patients with acoustic neuroma, brain stem disorder such as tumors of the posterior fossa with neuraxis impingement, as well as demyelinating disorders such as multiple sclerosis. It is certainly useful in the verification of neurologic normalcy in patients complaining of dizziness and vertigo.

Acoustic Stimulation↗

Ultrastructural observations on preneoplastic epidermoid metaplasia in the lungs of rats.

Epidermoid metaplasia, of a type that consistently progresses to epidermoid carcinoma, was induced in rats at the interface of pulmonary tissue and intrapulmonary deposits of beeswax that contained either benzo(alpha)pyrene or the heptane-soluble fraction of cigarette smoke condensate. The preneoplastic epithelium was searched for morphological harbingers of neoplasia and compared with the type of reactive bronchial metaplasia, rarely associated with cancer, that results from chronic murine pneumonitis. The carcinogen-laden beeswax caused both proliferation and migration of epithelial cells from bronchi adjacent to the wax deposits. These initial proliferating cells were characterized by a lack of differentiation and were similar to the basal cells of bronchial epithelium. The migrating epithelium rapidly established itself at the interface of wax and viable lung tissue as a highly differentiated, stratified squamous epithelium. This epithelium was not qualitatively different from normal squamous epithelium. However, quantitative differences were evident from both normal epithelium and the metaplastic epithelium resulting from nonspecific injury. In the preneoplastic epithelium, the first indications of aggressive behavior occurred in foci of dysplastic basal cells that sent cytoplasmic intrusions through defects in the basement membrane. Characteristically, these dyplastic basal cells had numerous infoldings of the nuclear membrane and prominent nucleolar alterations. All strata of preneoplastic cells contained excessively complex interdigitations of the plasma membrane and unusually large numbers of desmosomes and tonofilaments. In contrast, the nonspecific metaplastic epithelium consisted almost entirely of multilayered uniform cells that closely resembled immature but otherwise normal basal cells of respiratory epithelium.

Animals↗

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↗