Intracapsular implant rupture: MR findings of incomplete shell collapse

The objective of this study was to determine the frequency and significance of the MR findings of incomplete shell collapse for detecting implant rupture in a series of surgically removed breast prostheses. MR images of 86 breast implants in 44 patients were studied retrospectively and correlated with surgical findings at explanation. MR findings included (a) complete shell collapse (linguine sign), 21 implants; (b) incomplete shell collapse (subcapsular line sign, teardrop sign, and keyhole sign), 33 implants; (c) radial folds, 31 implants; and (d) normal, 1 implant. The subcapsular line sign was seen in 26 implants, the teardrop sign was seen in 27 implants, and the keyhole sign was seen in 23 implants. At surgery, 48 implants were found to be ruptured and 38 were intact. The MR findings of ruptured implants showed signs of incomplete collapse in 52% (n = 25), linguine sign in 44% (n = 21), and radial folds in 4% (n = 2). The linguine sign perfectly predicted implant rupture, but sensitivity was low. Findings of incomplete shell collapse improved sensitivity and negative predictive values, and the subcapsular line sign produced a significant incremental increase in predictive ability. MRI signs of incomplete shell collapse were more common than the linguine sign in ruptured implants and are significant contributors to the high sensitivity and negative predictive values of MRI for evaluating implant integrity.     

An analysis for menstrual data with time-varying covariates

This paper concerns the analysis of menstrual data; in particular, methodology to identify variables that contribute to the variability of menstrual cycles both within and between women. The basis for the proposed methodology is a parameterization of the mean length of a menstrual cycle conditional upon the past cycles and covariates. This approach accommodates the length-bias and censoring commonly found in menstrual data. Data from a longitudinal study of menstrual patterns and other variables among Lese women of the Ituri Forest, Zaire, illustrate the methodology. A small simulation illustrates the bias caused by incorrectly deleting the censored cycles.     

Cerebral vascular effects of angiotensin II: new insights from genetic models.

Very little is known regarding the mechanisms of action of angiotensin II (Ang II) or the consequences of Ang II-dependent hypertension in the cerebral circulation. We tested the hypothesis that Ang II produces constriction of cerebral arteries that is mediated by activation of AT1A receptors and Rho-kinase. Basilar arteries (baseline diameter approximately 130 microm) from mice were isolated, cannulated and pressurized to measure the vessel diameter. Angiotensin II was a potent constrictor in arteries from male, but not female, mice. Vasoconstriction in response to Ang II was prevented by an inhibitor of Rho-kinase (Y-27632) in control mice, and was reduced by approximately 85% in mice deficient in expression of AT1A receptors. We also examined the chronic effects of Ang II using a model of Ang II-dependent hypertension, mice which overexpress human renin (R+) and angiotensinogen (A+). Responses to the endothelium-dependent agonist acetylcholine were markedly impaired in R+A+ mice (P<0.01) compared with controls, but were restored to normal by a superoxide scavenger (PEG-SOD). A-23187 (another endothelium-dependent agonist) produced vasodilation in control mice, but no response or vasoconstriction in R+A+ mice. In contrast, dilation of the basilar artery in response to a NO donor (NONOate) was similar in R+A+ mice and controls. Thus, Ang II produces potent constriction of cerebral arteries via activation of AT1A receptors and Rho-kinase. There are marked gender differences in cerebral vascular responses to Ang II. Endothelial function is greatly impaired in a genetic model of Ang II-dependent hypertension via a mechanism that involves superoxide.     

Caregiver negative affect is a primary determinant of caregiver report of pediatric asthma quality of life.

BACKGROUND: Quality of life has increased in popularity as an outcome measure in health research. However, the measurement of quality of life has been questioned on methodologic grounds, as it often shows little association with objective measures of disease status. OBJECTIVE: For this report we studied the determinants of pediatric asthma caregiver report of quality of life and its relationship to disease burden. METHOD: Ninety-eight children who were admitted to a Pediatric Day Program for an asthma evaluation were enrolled in an outcome study. A complete set of medical records for the 2-year period before and after the admission was collected and systematically coded for health care utilization. Using the Pediatric Asthma Caregiver's Quality of Life Questionnaire, data were collected at baseline, discharge, and year after the admission. Caregiver negative affect (anxiety and depression), measured with the Brief Symptom Inventory, was also collected at baseline and discharge. RESULTS: Caregiver report of quality of life was unrelated to health care utilization at baseline but instead was significantly related to baseline caregiver negative affect. A significant relationship between health care utilization and quality of life was present at followup. The Emotional Function scale from the quality of life measure can account for most of the relationship between quality of life and negative affect. CONCLUSIONS: Caregiver affect may have a considerable influence on report of quality of life. Understanding the individual characteristics of the respondent is important when using a quality of life instrument as an outcome measure.     

Recall of medication during pregnancy: Validity and accuracy of an adjusted questionnaire

Objective — To study the validity and accuracy of an adjusted questionnaire on medical drug use during pregnancy eight years after the pregnancy. Methods — The ability of a questionnaire on medication during pregnancy to detect actual use (= sensitivity) was tested against information collected 8 years previously (in 1983–1984) from 473 women with high-risk pregnancies who delivered at the University Hospital Nijmegen, the Netherlands. Results — For separate drug groups, the sensitivity varied between 5% and 91%. The timing of use was recalled moderately well. Although specific questions on drug groups did improve the sensitivity as compared to an earlier questionnaire, the improvement was not enough to make the questionnaire valid. High maternal education, low birth weight, low gestational age and a low 5-min Apgar score were related to better recall. The sensitivity of the questionnaire depended on the behavioural score of the child, implying recall bias. Conclusion — Questionnaire data on drug use during pregnancy obtained eight years after delivery are not a valid source of information.     

Use of ultrasound to assess healing of a mandibular distraction wound.

PURPOSE: A standardized, noninvasive technique to assess healing of the mandibular distraction wound is not available. Current methods include clinical examination, plain radiography, and computed tomography. These imaging techniques are expensive and obligate the patient to serial radiation exposure. In addition, anatomic overlap and metal artifacts may obscure the distraction gap. In contrast, ultrasound has been shown to be a noninvasive, efficient, and inexpensive way to evaluate bone healing. The purpose of this study was to test the feasibility of ultrasound to evaluate an experimental mandibular distraction osteogenesis wound. MATERIALS AND METHODS: Distraction devices were placed via a submandibular incision into 24 minipigs. The protocol consisted of 0-day latency and distraction rates of 1, 2, or 4 mm/d for a 12-mm gap. The wounds were assessed in vivo after 0, 8, 16, and 24 days of neutral fixation. Ex vivo radiographs were used to estimate bone fill using a semiquantitative score. A semiquantitative ultrasound score was assigned, and the beam penetration depth was measured in millimeters. RESULTS: In all groups, clinical stability of the distraction wound increased with the duration of fixation. Plain radiographs, taken during neutral fixation, showed that the desired distraction gap was achieved and maintained. The ultrasound score increased with fixation time, whereas beam penetration depth decreased as expected. Ex vivo radiographs showed increasing bone fill score with time and paralleled the ultrasound score. CONCLUSIONS: The results of this feasibility study indicate that ultrasound is potentially useful for the assessment of bone formation in distraction osteogenesis wounds.