Biomedical subjects
Publications and source records attributed to H Mitchell.
Human papillomavirus infection (HPV) of the cervix has been an area of intense research during the 1980s. Knowledge has expanded rapidly and new advances have often challenged previous ideas. This review is designed to help the general practitioner remain up-to-date with recent research findings and to assist in the management of women with HPV infection.
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OBJECTIVE: To assess adherence to recommendations for an early repeat cervical smear test in women with reports of cytological abnormalities, and to evaluate the impact of reminder letters to medical practitioners when such smear tests are overdue. DESIGN: Observational study. SETTING: Cytology (gynaecological) service for Victoria, Australia. SUBJECTS: Two groups of women who had abnormal cervical smears during 1985. Women in group A had some evidence of an important dysplasia and were advised to have a repeat smear in three months' time whereas women in group B had a less serious abnormality and were advised to have a repeat smear test in six months' time. In all, 971 of the 1036 women in group A and 1401 of the 1464 women in group B were eligible to have a repeat smear analysed by the service. INTERVENTION: If a repeat smear had not been received within three months of the recommended date a reminder letter generated by the service's computer was sent to the medical practitioner who had taken the smear. END POINT: Thirty six months after the report on the abnormal smear was issued. MEASUREMENTS AND MAIN RESULTS: In all, 870 (90%) of the women in group A and 1154 (82%) of the women in group B had a repeat smear test. The mean time to a repeat test was 3.0 months (95% confidence interval 0.5 to 16.4) in group A and 6.0 months (1.2 to 30.3) in group B. The reminder letter to the practitioner potentially increased the rate of return for a repeat smear test by 18% in group A and 24% in group B. Adherence to the recommendation for a repeat test increased with increasing age. CONCLUSIONS: Achieving high rates of follow up smear tests and appropriate management in women with cytological abnormalities is critical to the impact of a screening programme for cervical cancer. The reminder system used in this study was not labour intensive or expensive and provided a fail safe mechanism for ensuring that reports of abnormal smears were not overlooked.
A review of published studies that have evaluated cervicography as a screening-test for the presence of cervical cancer is presented. Significant problems with the use of cervicography at a population level can be anticipated, in particular, a high proportion of women with uninterpretable test-results and an unacceptably-low positive predictive value. Colposcopy was unable to distinguish adequately the true status of many women with suspicious cervicograms; half the women with a cervicogram that was suggestive of cancer and an abnormal result by colposcopy had normal or benign histological findings. The impact of cervicography on the morbidity and mortality of cervical cancer is unproved. On current evidence, cervicography would not appear to be suitable for use as a screening-test, either as a replacement for, or as a supplement to, the Papanicolaou smear-test.
It has been suggested that successful batsmen in cricket are not distinguished by their fast speed of visual information intake. A study is presented in which a season's batting averages for twenty regular cricketers, all members of the same local team, were correlated with the cricketers' visual inspection times. The correlation was -0.63 (p less than 0.005), suggesting that the successful batsmen were faster at picking up information from briefly presented visual displays. When the age factor was eliminated, the partial correlation between inspection time and batting average remained significant at -0.52 (p less than 0.01). This finding is discussed with respect to the sources of information available from a ball in flight.
An observational study of the influence of diathermy on the rate of subsequent cytological evidence of cervical intraepithelial neoplasia and/or human papillomavirus infection among women with a histological diagnosis of cervical human papillomavirus infection is presented. After the histological diagnosis of human papillomavirus infection, 35% (23/65) of women who were not diathermied had persistence/recurrence of cytological abnormalities compared with 30% (60/203) of the women who were diathermied at the time of the biopsy. The rate ratio for further abnormality among women who did not have a diathermy relative to those who did was not significantly different at 1.25 (95% confidence interval 0.77-2.03). This study had a power of 77% to detect a true rate ratio of 2 at the 0.05 level of significance. This data does not provide strong evidence that diathermy is appropriate management for women with cervical human papillomavirus infection without evidence of dysplasia.
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Pap smears reported by the Victorian Cytology (Gynaecological) Service between 1980 and 1987 for teenagers show a profile of abnormality which is similar to that for women for all ages. More than 90% of the cytology report have consistently been reported as normal or showing minor benign abnormalities only. No evidence of an increasing rate of infection with human papillomavirus is apparent, with the infection rate as determined cytologically being constant at around 4% to 5% during 1981 to 1987. Some increase in the proportion of women having associated changes of CIN is apparent. No case of invasive cancer in teenagers has yet been confirmed. These data suggest that the teenagers in Victoria who are having Pap smears reported by the Victorian Cytology (Gynaecological) Service are not a high risk group for cervical cancer during their teenage years, but may be a high risk group during later years.
Mortality rates for stroke in 1971, 1974, 1977, and 1980 were obtained for residents of Allegheny County in western Pennsylvania. Hospital case fatality ratios were also obtained in the same 4 years for those discharged with the diagnosis of stroke (ICD 430-438 of the Eighth and Ninth Revisions of the International Classification of Disease) in two large hospitals (greater than 400 beds). Age-adjusted mortality rates per 100,000 population have declined significantly in this period for the whole county as well as for the four sex-race groups. Case fatality ratio in the two hospitals of the study has decreased from 19.6 to 11%. A change in the severity of the disease manifested by a reduction in the number of comatose patients has occurred, and this reduction in comatose patients was responsible for greater than 80% of the decline in case fatality ratio. Coma appears to be the best predictor of mortality among hospitalized stroke cases (r = 0.6, p less than 0.00001). The recent introduction of computed tomography for the diagnosis of stroke in the late 1970s was accompanied by a twofold increase in the survivorship of stroke patients. However, this increase in survivorship may reflect selection bias and is based on ecological association. Further studies are needed to examine the role of computed tomography in improving survival.
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Cytological evidence of human papillomavirus infection was present in 4.1% of the smear-tests that were received by the Victorian Cytology (Gynaecological) Service during 1982-1985. The prevalence rate among women was estimated to be 2.6% in 1984; for one-third of the women this was a change from their previous cytological status. The prevalence of papillomavirus infection was noted to vary with age and referral source; higher proportions were seen in the age group, 20-24 years, and in the cytological results of women who were attending either a sexually-transmitted diseases clinic or Aboriginal health cooperatives.
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Methodological differences exist in the evaluation of Valsalva's Maneuver. Linear and nonlinear mathematical models were described for beat-to-beat changes in blood pressure and R-R intervals occurring during the strain and release phases of Valsalva's Maneuver. This study indicated that the strain phase is linear, whereas the release phase is nonlinear; the release phase consists of a "lag phase," a "breakpoint," and an "overshoot phase." The alpha-adrenoceptor antagonist, alfuzosin, reduced baroreflex-mediated tachycardia during the strain phase and prolonged the "time lag" and "pressure lag" during the release phase; the latter change was due entirely to the reduced systolic pressure that occurred with alfuzosin at the end of the strain phase.
The delay between the issuing of an abnormal cytology report and the subsequent histological diagnosis has been studied for women diagnosed with carcinoma in situ, microinvasive cancer and invasive cancer in Victoria during 1985-1986. The median delay was 0.75 weeks for women with invasive cancer, 6.2 weeks for women with microinvasive cancer and 4.9 weeks for women with carcinoma in situ. Little variation was apparent with the type of practitioner taking the smear or with the area of residence of the woman. Ten of the 235 women in this study had delays of greater than 20 weeks. Five of these women were ultimately shown to have microinvasive or invasive cancer where the cytology report had indicated a lesser degree of neoplastic change. It is possible that the lesions progressed during this time.
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In recent years there has been a dramatic increase in the incidence of human papillomavirus infection of the female genital tract. Since the primary diagnosis of this condition is almost invariably based on cytologic observations, the diagnostic criteria are of paramount importance. The diagnosis is usually based on the presence of koilocytes, or balloon cells, and dyskeratotic cells. Although these cells remain fundamental to the diagnosis, it is important to recognize other possible cytologic manifestations of the disease. Follow-up studies indicate clearly that any woman with cytologic evidence of HPV infection has a greatly increased risk of developing cervical intraepithelial neoplasia. Morphologic attempts to quantify this risk are unreliable. The studies described and quoted in this paper would suggest that all women with the cytologic changes of HPV infection, with or without evidence of cervical intraepithelial neoplasia, should be managed with extreme caution.