Age and clinical immunity to infections with Chlamydia trachomatis.

BACKGROUND AND OBJECTIVES: The prevalence of chlamydial infection decreases with age possibly in part because of increasing immunity. GOAL OF THIS STUDY: To determine whether increased age is an independent predictor of decreased chlamydial infection and whether chlamydia-specific antibody titer and blastogenesis increase with age. STUDY DESIGN: Data from all patients cultured for Chlamydia trachomatis between January 1984 and August 1989 were examined and multiple logistic regression models were used to identify the independent predictors of culture positivity. Antichlamydial antibody titer and chlamydia-specific blastogenesis were examined for a subset of patients for correlation with age. RESULTS: Young age was found to be predictive of chlamydial infection independent of all factors examined in men and women. Antibody titers had no relation to age (n = 245) whereas the level of blastogenesis correlated only weakly with age (n = 155). CONCLUSIONS: Assays of systemic immunity do not reflect the protection from chlamydial infection associated with age.

Abdominal duplex ultrasound screening for occult aortic aneurysm during carotid arterial evaluation.

PURPOSE: The purpose of this study was to investigate the use of a modified abdominal ultrasound examination, which was performed at the time of routine diagnostic carotid artery duplex evaluation, to identify patients at risk for aortic aneurysms. METHODS: A prospective study was undertaken that consisted of a limited ultrasound examination of the abdominal aorta on patients referred to our facilities for duplex carotid evaluation. One hundred thirty-one patients were included in the study; 52% were men and 48% were women, who ranged in age between 40 to 93 years. These patients were not known or suspected to have an abdominal aortic aneurysm. RESULTS: Eleven infrarenal aortic aneurysms (8.4%) were detected, four in patients with positive carotid studies (11%) and seven in those with negative studies (7%); size ranged from 3.0 to 7.5 cm. Categoric data analysis did not produce significance, but a stepwise regression and discriminant analysis model revealed a significant relationship between abnormal velocities and occlusive changes in the carotid arteries and the presence of aortic aneurysms. CONCLUSIONS: Hemodynamically significant carotid artery disease, as diagnosed by duplex examination, appears to be a definite marker for an increased incidence of abdominal aortic aneurysm when compared with the general population. When selective abdominal aortic ultrasonography is done in conjunction with the carotid study, the requirements of additional equipment and technologist time are modest, and the potential benefit to the patient may be significant.

Factors predicting the outcome of regional streptokinase therapy for peripheral arterial occlusions.

Low dosage regional streptokinase therapy has become increasingly popular as an alternative to surgical treatment in acute and chronic arterial occlusions. Success rates are reported between 70 and 100 per cent. This is surprising, considering the paucity of data in the literature regarding the type of lesion treated, objective criteria for good results and predictive factors of success. In a review of 22 acute and chronic arterial occlusions of the lower extremity treated with low dosage regional streptokinase, the outcomes were grouped as either favorable or unfavorable. A success rate of 36 per cent was achieved. The two outcome groups were compared with regard to pre-existing diseases or risk factors, indications for treatment, duration of symptoms or level of occlusion. No significant difference was found. With regard to pretreatment runoff, 100 per cent of the patients in the favorable outcome group were found to have good runoff as opposed to only 21 per cent of the patients in the unfavorable outcome group. Of the patients who also had PBD procedures, all of those in the favorable group had good runoff, and all in the unfavorable group had poor runoff. In nearly achieving statistical significance, a trend was noted establishing embolic lesions as more favorable than thrombotic lesions. We conclude that our low success rate with low dosage regional streptokinase therapy is due to our strict criteria for success and the nonselective nature of the patients we studied. As a result of these findings, we do not support the preferred use of low dosage regional streptokinase therapy in arterial occlusion. However, in patients who represent high surgical risks, a trial of low dosage streptokinase therapy seems indicated if favorable predictors of success, such as good pretreatment runoff, embolic lesion and mild symptoms, are present.