Janet Parker

Poor prognosis associated with thrombocytosis in patients with cervical cancer

The medical records of 113 patients treated with radiation therapy for invasive cervical cancer between 1975 and 1985 were retrospectively reviewed. Patients with thrombocytosis (platelet count > 400,000/μ1) were compared with those with normal platelet counts. Thrombo‐cytosis was present at the initiation of therapy in 20 (17.7%) of the 113 patients. The 5‐year cumulative survival rate for the 93 patients with normal platelet counts was 65%, whereas it was 25% for the 20 with thrombocytosis (P < 0.0001, log‐rank test). Using Coxs proportional hazards model, thrombocytosis continued to correlate strongly with poor survival even when adjusted for histo‐logic type, patient age, and disease stage (P < 0.001). Thrombocytosis is an independent indicator of poor prognosis in patients with cervical cancer.

Cancer prevention education in United States medical schools

The Cancer Education Survey collected data from 126 of 128 US Medical Schools on the current status of cancer-related educational activities for undergraduate medical students. The study was conducted by a Supervisory Committee of the American Association for Cancer Education, with funding from the American Cancer Society. The survey obtained data concerning institutional characteristics in support of undergraduate medical student cancer education, ie, administrative structures, current cancer-related curricula, sources of financial support, and anticipated changes in these characteristics. Institutions were also queried on specific topics of cancer prevention, detection, and diagnosis that might be taught as identifiable areas of instruction for medical students. Three-fourths of the institutions had a lecture on the principles of cancer screening, and, among those, nearly three-fourths classified it as a part of a required course or rotation. Detection of common cancers is taught in virtually all institutions. The least likely cancer prevention lecture topics are related to prevention and cessation of smoking, a well-verified cancer risk. Also, no consistent pattern emerges that might indicate that association with a cancer center imparts to a medical school a greater emphasis on delivery of cancer prevention topics.

Cerastes cerastes (Egyptian sand viper) venom induced platelet aggregation as compared to other agonists

The Egyptian Sand Viper (Cerastes cerastes) crude venom and subfractions were, for the first time, shown to induce platelet aggregation with agonist activities present in two subfractions. The combined activities of the crude venom components behaved in a unique fashion as compared to the platelet agonists, ADP, collagen and thrombin. The action of the venom was inhibited by conditions that increased cAMP, partially required the formation of thromboxane A2 and was inhibited by the serine protease inhibitor PMSF while being only partially sensitive to leupeptin or soybean trypsin inhibitor. One of the fractionated venom agonists strongly induced serotonin release while the other venom agonist essentially did not. Further characterization of the Cerastes cerastes venom components should broaden our knowledge of the pathology of snake venoms, platelet aggregation and their potential therapeutic value.

Instructional methods and the use of teaching resources in cancer education curricula

The findings on cancer teaching methodology presented in this abstract come from an American Association for Cancer Education (AACE)/American Cancer Society-sponsored survey of American allopathic medical schools in 1989 and 1990 to determine how and how well cancer is presented in the medical school curriculum. Responses were received from 126 institutional and approximately 1,000 faculty respondents. Approximately one-third (368) of faculty respondents indicated the use of specific learning objectives; utilization does vary across disciplines. The lecture remains the dominant form of instructional method. Computers were reported as an instructional modality by only 16% of the faculty respondents. Prepared audiovisual instructional materials appeared to be widely utilized. Use varied from 86% for 35mm slides to 11% for video discs. Faculty favored the development of new teaching materials for ten topic areas ranging from approximately 40% for early detection and prevention to a low of approximately 25% for rehabilitation and continuing care. The survey identified an underutilization of existing outpatient facilities and tumor registries for cancer teaching purposes. The findings give rise to questions concerning the appropriateness of the match between specific instructional goals and the teaching methods employed. Eight recommendations designed to strengthen cancer training are made.

The bioluminescent detection of platelet released ATP: collagen-induced release and potential errors.

The bioluminescent detection of ATP released from activated platelets is an important diagnostic and experimental assay. Potential errors in the interpretation of the data may be introduced due to the lability of luciferin-luciferase and the amount of platelet agonist employed. Loss of luciferin-luciferase activity is temperature dependent with a 50% decrease in activity in 1-4 min at 37 degrees C. Plasma components do not appear to contribute to the inactivation of the detection system. Due to the significant loss of enzyme activity at variable times, the method of standardizing ATP concentrations is crucial for the accurate determination of ATP released from activated platelets. A nearly 5-fold error is introduced into the routinely employed assay procedure where the standard ATP concentration is determined 5 min after the addition of agonist. This report demonstrates that the standard ATP concentration must be determined with a separate platelet sample at the same time as the ATP was released from the agonist-induced experimental platelet sample. A second significant error in the assay system may be introduced by the agonist concentration employed even when the final level of aggregation is the same. When collagen is employed as the agonist the amount of ATP released appears to depend, in part, on the initial intensity of the aggregation response and not on collagen type (Type I versus IV). The corrective procedures described here for the detection of ATP are not likely to change the qualitative results of most studies but would significantly alter the quantitative results.

Survey design and observations relating to cancer education funding

A survey has been conducted of cancer education programs for medical students in United States medical schools by the American Association for Cancer Education with grant support from the Department of Detection and Treatment of the American Cancer Society (formerly the Professional Education Department). Two questionnaires were used, an Educational Resources Questionnaire (ERQ), which 126 of the 128 medical schools completed and returned, and a Faculty and Curriculum Questionnaire (FCQ), which was completed and returned by 1,035 faculty members who had been named as active in undergraduate medical student cancer education by respondents in each school who had been designated by the Deans Office to complete the ERQ. Overall conclusions included: (1) increased coordination of cancer education activities is a major need in many schools; (2) there is widespread interest in the further development of cancer education objectives; (3) development of a national cancer education curriculum is needed; (4) there is interest in the development of improved instructional materials and methods; (5) development of evaluation methods is needed for cancer education programs; and (6) an ongoing funding process is needed to provide support for interdepartmental coordination of cancer education activities. Cancer prevention and detection topics were ranked above cancer treatment in plans for future curriculum emphasis. More detailed conclusions and recommendations are provided in this publication and three subsequent articles in this issue of the Journal of Cancer Education.

Aggregation of human and canine platelets: Modulation by purine nucleotides

This study compared the responses of canine and human platelets to various aggregating agonists in the presence or absence of extracellular ATP and ATP analogues. Canine and human platelets were approximately equally reactive with ADP or collagen while the canine platelets were about 10 fold more sensitive to thrombin. Canine platelets were insensitive to the thromboxane mimetic U46619 but were synergistically aggregated by a mixture of ADP and U46619. Human platelets were very sensitive to U46619. Aggregations of human platelets with all of the above agonists were inhibited by extracellular ATP; beta, gamma methylene ATP (beta gamma ATP) and benzoyl ATP (BzATP) with a rank order suggestive of an interaction with P2x-like purinoceptors which support our previous findings. The comparable aggregations of canine platelets were likewise inhibited by ATP and its analogues but with a rank order suggestive of an interaction with P2y-like purinoceptors. ATP inhibited U46619- and ADP-induced aggregation of human platelets and ADP-induced aggregation of canine platelets, presumably, in part, due to competition for the ADP P2T receptor. However, when U46619 was added to either ATP or ATP analogue-inhibited ADP-treated canine platelets, the inhibition was nullified. Furthermore, we demonstrated, for the first time, that the canine thromboxane receptor becomes reactive to U46619 alone after incubation at room temperature for 3.5-5 hrs while human platelets become inactive under similar conditions. The implication of these studies is that there are significant differences in the canine and human platelet thromboxane and purine receptors. The future characterization of these differences and the mechanism by which they function should further our understanding of the impact of extracellular ATP on hemostasis and thrombosis.