Scimitar etcetera--the dysmorphic right lung

'Dysmorphic lung' is introduced as a term to describe any complex congenital malformation which involves both abnormal vascular morphology and disordered growth of a whole lung. The major group within this definition is the scimitar syndrome, which we choose to mean a hypoplastic lung with anomalous venous drainage and various degrees of collateral arterial supply. Nine typical cases of scimitar are presented, with three closely related cases. Six other cases of dysmorphic lungs are also present. The relationships between the groups are discussed, and an effort is made to clarify the nomenclature used in this condition.     

Linear transformation and the interpretation of MMPI T scores

Raw scores for the clinical scales of the MMPI can be changed to T scores by linear transformation. However, if the underlying distributions of raw scores are not distributed normally, one cannot assume that the traditional point of significance, T score 70, falls at the 97.7 percentile. Our analysis of the improved Minnesota normal sample described by Hathaway and Briggs in 1957 revealed statistically significant degrees of skewness on most of the clinical scales. We suggest that clinicians consider more conservative interpretation for scales 1 (Hs), 2 (D), 7 (PT), 8 (SC), and 9 (MA) for females and for scales 1 (Hs), 2 (D), 4 (PD), 7 (PT), 8 (SC), and 9 (MA) for males.     

Oscillatory potentials and the b-Wave: Partial masking and interdependence in dark adaptation and diabetes in the rat

Background Diabetes inhibits dark adaptation and both processes alter the electroretinogram (ERG) in similar ways. This study aimed to investigate the relationship between oscillatory potentials (OPs) and the b-wave during dark adaptation and to determine if this relationship changes during the development of diabetes. Methods Twenty-one rats were assigned to adaptation, control and diabetic groups. Rats were dark adapted for periods between 20 minutes and 4 hours, and ERGs recorded. Diabetes was induced with streptozotocin, and ERGs measured after 3, 6, 9 and 12 weeks after injection. Results Increasing periods of dark adaptation led to a logarithmic increase in the amplitude of the b-wave and the OPs. This was accompanied by a decrease in the peak times of the OPs and b-wave. Total OP amplitude and b-wave amplitude were linearly related, allowing an empirical OP constant to be developed to describe the relationship between the two parameters. Diabetes led to a progressive decrease in the amplitude and increase in the peak time of all waves. The OP constant decreased in a linear fashion with increasing duration of diabetes. Conclusions It is argued that OP masking of the b-wave could explain previous inconsistencies in reported ERG changes in diabetes and that a slowing of dark adaptation does not account for these ERG changes. The report concludes that the OPs and b-wave amplitudes and latencies are intimately related in the normal retina and that this correlation is lost predictably during the development of diabetes.     

Rotavirus-induced changes in the microcirculation of intestinal villi of neonatal mice in relation to the induction and persistence of diarrhea

Using a histochemical peroxidase technique, under conditions that preferentially stain erythrocytes, we have shown changes in the microcirculation of villi of neonatal mice infected with murine rotavirus. Between 18 and 48 h postinfection (PI), throughout all areas of the small intestine there occurred, sequentially, a marked ischemia and atrophy of villi. By 72 h PI, villi had recovered their normal height and showed incipient hyperemic microcirculation. At 96 h PI, hyperemic microcirculation was most marked. Between 120 and 144 h PI, a second phase of villus atrophy occurred, which was more attenuated and confined to the upper and middle regions of the intestine. This phase was not accompanied by a wide-spread ischemia of villi: a minority of villi were short and ischemic but many appeared hyperemic. Recovery of villus microcirculation occurred at 168 h PI, which coincided with recovery from diarrhea. These changes in villus microcirculation are discussed in relation to the pathology and pathophysiology of rotavirus infection. We make two novel suggestions. First, the reduction in red cells flowing through villi in the early stages of the infection instigates hypoxia and hence atrophy of villi. The ensuing but ephemeral increase in rate of cell division, necessary for the reconstitution of villi, induces hypersecretion. Second, the increase in numbers of erythrocytes found in villi during their regrowth phase and throughout the remaining time course of the infection perturbs the countercurrent system, lowering the osmolality of the hyperosmotic zone located at villus tips, thereby impairing water absorption and prolonging diarrhea.     

Post-mortem changes in hair bundles of the guinea pig and human cochlea studied by high-resolution scanning microscopy

High-resolution scanning electron microscopic studies have been made on the guinea pig cochlea on material fixed from 15 min to 4 h post-mortem. Changes in the surface texture and cross-links of stereocilia were detected after only 15 min. Such changes included an increase in granularity of the surface membrane, thickening, stretching and fracturing of all types of cross-links accompanied by splaying apart and loss of rigidity of stereocilia. These changes were more pronounced in the basal turns of the cochlea and in general increased in severity and spread more apically with increasing times post-mortem. By 4 h, many hair bundles consisted of a fused amorphous mass in which individual stereocilia were not discernible. Remarkably at this time, some hair bundles appeared to have suffered little damage. These results will facilitate better discrimination between effects solely due to post-mortem necrotic changes and those due to specific actions of ototoxic drugs and other insults.     

A spectrum of skeletal anomalies associated with pulmonary agenesis: possible neural crest injuries

Six cases of unilateral pulmonary agenesis with skeletal and other deformities have been diagnosed in our hospitals. The various pulmonary, spinal, rib and limb anomalies with their possible inter-relationships were examined and described in detail and comparison with previously reported cases was made. It became apparent that the limb abnormalities which most constantly involved hypoplasia of the phalanges of a thumb with varying metacarpal and radial anomalies, were ipsilateral to the pulmonary agenesis in all cases. The spinal deformities involved degrees of failure of segementation of T1-T3 with other vertebrae randomly involved. Rib abnormalities also varied and did not necessarily correspond to the same side as the pulmonary agenesis. The concept of the anomalies all being part of a group of neural crest injuries was then explored.