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Biomedical subjects

A Evans

Publications and source records attributed to A Evans.

At least 397 records · Page 22Linked to original sources
PubMed1978

Evaluation of a library program in a Carnegie model area health education center.

The evaluation strategy of a medical library program within an Area Health Education Center is described. One of about thirty programs in the AHEC project, this library program was singled out as the first to be evaluated both because it was considered a key part of the total program and because a fair amount of quantitative data were available for measurement. Eleven hospitals of the thirty-nine in the area were selected for the study. Two specific and measurable objectives, the evaluation method, instruments, and results are presented. Finally, several important issues raised in conjunction with the evaluation are discussed in terms of the implications of evaluation and policy making.

California↗
PubMed1977

Continuous infusion pressure-monitored sialography.

A technique for sialography has been developed which gives reproducible radiographs. By employing a constant infusion pump to deliver 0.2 ml of contrast medium per minute the patient does not experience pain and glandular detail is not obscured due to overfilling. Aqueous and oily contrast media may be used satisfactorily but there is greater latitude in times of exposure with the aqueous media.

Contrast Media↗
PubMed1977

Studies of the antigenicity and immunogenicity of bromelain-pretreated red blood cells.

The effects of the proteolytic enzyme bromelain (Br) on the antigenicity and immunogenicity of sheep and mouse red blood cells (RBC) have been investigated. The results presented support the previous claim that there are antigens present on Br RBC that are not present in an exposed form on untreated RBC and that Br RBC have lost some of the antigens present on the surface of normal RBC. The susceptibility of Br RBC to osmotic lysis was very similar to that of normal RBC, implying that the modified RBC were not more fragile than normal RBC. Injection of mice with Br mouse-RBC did not increase the unusually high "background" number of cells producing IgM antibodies against Br mouse-RBC and mice did not mount delayed-type hypersensitivity reactions against Br mouse-RBC, either before or after sensitizing injections of Br mouse-RBC. However, mouse-RBC and Br mouse-RBC elicited similar antibody responses in rabbits and guinea pigs. Although mice appeared unresponsive to Br mouse-RBC injections, delayed-type hypersensitivity responses and antibody production in primary and secondary responses were of similar levels irrespective of whether sheep-RBC or Br sheep-RBC were used as immunogens. From these studies it appears that mice have B-cells producing antibodies against the "new" antigens on Br mouse-RBC, but there are no T-cells that respond to these antigens by way of "helper" activity in antibody production or by way of cell-mediated immune reactions.

Animals↗
PubMed1976

Decreased risk of radiation-associated second malignant neoplasms in actinomycin-D-treated patients.

One hundred two long-term survivors of childhood cancers with second malignant neoplasms (SMNs) were collected from 10 institutions. Forty-seven cases fulfilling study criteria were studied to determine the risk of developing a SMN in irradiated fields after exposure to various chemotherapeutic agents. The case control method was used. The risk of developing such tumors was decreased by a factor of 7 in patients receiving actinomycin-D (AMD). The "protective" effect of AMD was more pronounced in patients receiving repeated courses of the agent. No change in relative risk was found for children given antifolates, the vinca alkaloids, or alkylating agents. AMD "protection" is an unexpected finding because the agent is an oncogen in animals and an enhancer of radiation, the latter being a known carcinogen. Possible mechanisms, which remain speculative, are discussed. These results indicate the need for careful long-term observation of cancer survivors to gain understanding of the late effects of multimodal treatments.

Child↗
PubMed1976

Application of xeroradiography in sialography.

Sialography was carried out in healthy volunteers and in patients with Sjögren's syndrome. A comparison was made between xeroradiography and conventional radiography. Superior images were obtained with xeroradiography and this technique also tended to reveal glandular structure which was obscured by overlying bone when using conventional radiography. In addition to this, there was considerably greater latitude in exposure and the skin dose of radiation using xeroradiography was slightly less.

Humans↗
PubMed1976

Localization of phytochrome in etioplasts and its regulation in vitro of gibberellin levels.

Etioplasts isolated from barley leaves and purified on a Sephadex G-50 (coarse) column were characterized by electron microscopy and nucleic acid analysis. The majority of etioplasts retained an intact outer envelope, and contamination by other fragments was extremely low. The level of gibberellin-like substances extractable from intact etioplast suspensions was enhanced within 5 min of the termination of a saturating red irradiation, and the response was far-red reversible. Ultra-sonication caused a 3-fold increase in extractable activity both in dark control suspension and suspensions treated with red light. It is concluded that phytochrome, as a function of its interconversions, probably causes the transport of gibberellin from inside the etioplast into the surrounding medium. This leads to increased production of active gibberellins, possibly by release of feedback control of late steps of the biosynthetic pathway. Dual wavelength difference spectrophotometry has demonstrated the presence of a proportion of total cellular phytochrome within the etioplast.

Journal Article↗
PubMed1976

Effects of droperidol in management of vestibular disorders.

The chemo-therapy of vestibular disease has involved a wide spectrum of pharmacological agents insofar as their mode of action is concerned. In our experience, however, droperidol is one pharmaceutical agent which is remarkably effective in depressing vestibular disturbance regardless of etiology. This medication (also called Inapsine) belongs to a relatively new class of compounds known as butyrophenones and its pharmacological action can best be described as a dopa blocking agent. The activity of droperidol on the nervous system first became evident when it was used in combination with the potent analgesic fentanyl citrate in order to produce an anesthetic condition that has been termed neuroleptanalgesia. This mixture (also called Innovar) is rapid in action and results in complete suppression of vestibular activity of both normal subjects and those with Ménière's disease as described by Dowdy, et al., in a preliminary report. These impressive results have prompted us to evaluate the effectiveness of this medication in the treatment of different disorders of the labyrinth. The patients chosen for evaluation were referred for vestibular examination at the Toronto General and St. Michael's Hospitals. Electronystagmography was used to record objectively the effects of the drugs being tested while subjective symptoms including side effects were also noted. These studies involved 20 patients receiving Innovar while 12 patients were tested with Inapsine. Innovar administered in a single dose (droperidol 5 mg, fentanyl 0.1 mg) to patients undergoing acute episodes of vestibular disease (vestibular neuronitis and Ménière's disease) was found effective in the following symptoms and/or signs: nausea, vertigo, nystagmus, the positive past-pointing test and the Romberg test. Innovar appeared to be effective in the amelioration of vomiting although the population was too small to demonstrate statistical significance in this regard. The drug mixture appeared to have no effect on improving auditory acuity and had no significant effects on tinnitus. Adverse reactions to the drug combination were unusual, and, occurring in three patients, were mild as manifested by drowsiness. Since the above findings confirmed the marked effectiveness of the fentanyl-droperidol mixture in the management of vestibular disease, it was decided to determine the relative effectiveness of the droperidol component alone and this was determined by comparing the effectiveness of the drug with placebo in a double-blind study. Review of our findings involving this double-blind study indicates significant responses to Inapsine. This therapy clearly provided the statistically significant response (p less than 0.1, Fisher's Exact Test). This was particularly apparent at the 60-minute evaluation point. While some of the patients receiving Inapsine had recovered earlier, by 60 minutes none of the placebo patients but all of the Inapsine patients had recovered from the vestibular symptoms of Ménière's disease...

Acute Disease↗
PubMed1974

The impact of chemotherapy on advanced neuroblastoma. Survival of patients diagnosed in 1956, 1962, and 1966-68 in Children's Cancer Study Group A.

Survival statistics from 50 children with disseminated neuroblastoma, treated according to two CCSGA protocols between 1966 and 1968, are compared to those collected by Sutow and associates for 1956 and 1962. Little improvement occurred in the median survival rates of the children in these groups. Survival at 24 months is 13, 22, and 13 per cent, respectively, for the three groups. The lack of improvement in the median survival rate following treatment with a combination of VCR and CPM is attributed to an initial response rate of less than 40 per cent in the treated patients. The survival of patients who did respond, when compared to those who did not, was twice as long (15 vs. 7 months). Clearly, improved chemotherapy or other modes of treatment are needed for patients with advanced neuroblastoma at the time of diagnosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1972

The development of TRIC organisms in cell cultures during multiple infection.

The relationship between multiplicity of infection and the yield of organisms and of polysaccharide was studied in BHK 21 cells infected with TRIC organisms. Although an increase in the multiplicity of infection resulted in an increase in the absolute number of organisms per culture, there was a decrease in relation to the number of infecting organisms. The amount of polysaccharide produced was independent of multiplicity of infection; it was not limited by the concentration of glucose in the medium. Polysaccharide leaked from cells and was slowly broken down in the culture medium.

Animals↗