Assessment of deposition of inhaled aerosol in the respiratory tract of man using three-dimensional multimodality imaging and mathematical modeling.

Multimodality medical imaging enables measurement of the three-dimensional spatial distribution of a radiolabeled aerosol within the lung. Using a conceptual spatial morphological model these data may be transformed to provide information on deposition per airway generation. This methodology has been used to study the intrapulmonary deposition patterns of two formulations of a metered dose inhaler and two nebulizers in control subjects. The nebulizer study has also been stimulated using a computer model of deposition. The comparison between derived experimental results and those from computer modeling shows areas of agreement, although there are also areas of discrepancy. The new methodology has considerable potential value in the fields of inhalation therapy and deposition modeling, although more detailed validation is still required.     

Postoperative pulmonary toxicity associated with mitomycin-C therapy.

As more patients survive cancer, and as more sophisticated multidrug antineoplastic protocols are developed, the chances of an anesthesiologist's coming into contact with patients who have been treated with such protocols are increasing. The anesthesiologist who must administer anesthesia to a patient who has had chemotherapy must be cognizant of the particular antineoplastic agents that have the potential for producing occult pulmonary dysfunction. Anesthetic management of these cases must be carefully planned and titrated to prevent further lung injury.     

Cervical Anterior Spinal Cord Infarction

Spinal cord infarction or ischemia predominates in the thoracic region, less so in the cervical and lumbar regions. Different etiological factors have been implicated in anterior spinal artery syndrome. Magnetic resonance imaging (MRI) allows in vivo imaging of spinal cord disease, including infarction. A 31-yearold, previously healthy man had an acute onset of interscapular pain, followed by rapid development of quadriparesis associated with paresthesias and mild bladder dysfunction. Initial MRI of the cervicothoracic region demonstrated normal findings. A repeat study obtained 6 days later showed marked increase in the cervical cord size, especially at the C6-7 level. On the T2-weighted sagittal series and after gadolinium injection, increased signal in the anterior portions of the cord extending from C-4 to the T2-3 interspace was noted. This was most prominent at the C-6 and C-7 levels. The coronal views revealed abnormal high signal in the region of the anterior horns of the gray matter, a finding that is recognized as an “owl's eyes” pattern. Because the MRI changes of cerebral infarction may succeed a clinical event by hours or days, accurate diagnosis may require delayed or repeated studies. This report suggests that the diagnosis of spinal cord disease requires a similar evaluation.     

Surface area estimation: pocket calculator v nomogram.

Three sheets of 10 surface area determinations were completed by 10 subjects using a nomogram and a formula. The formula was faster to calculate, 4.27 v 7.6 minutes for each sheet, and resulted in fewer serious errors (three v 30 errors).     

Unique variant of partial anomalous pulmonary venous connection with intact atrial septum

Summary Partial anomalous pulmonary venous connections (PAPVCs) are rare in association with an intact atrial septum. However, the diagnosis should be considered in patients with otherwise unexplained findings of left-to-right shunt and right heart enlargement. An unusual variant is presented, which we considered unsuitable for operative repair, based on findings at catheterization. Developmental, hemodynamic, and surgical considerations are discussed.     

Non-hierarchical logistic models and case-only designs for assessing susceptibility in population-based case-control studies

This article describes how genetic components of disease susceptibility can be evaluated in case-control studies, where cases and controls are sampled independently from the population at large. Subjects are assumed unrelated, in contrast to studies of familial aggregation and linkage. The logistic model can be used to test collapsibility over phenotypes or genotypes, and to estimate interactions between environmental and genetic factors. Such interactions provide an example of a context where non-hierarchical models make sense biologically. Also, if the exposure and genetic categories occur independently and the disease is rare, then analyses based only on cases are valid, and offer better precision for estimating gene-environment interactions than those based on the full data.