Pulsus paradoxus is associated with many clinical conditions and is defined as a greater than 10 mm Hg end-inspiratory decrease in systolic blood pressure. Kussmaul's original definition of pulsus paradoxus is presented, along with an explanation of his choice of the term "pulsus paradoxus." A case of pulsus paradoxus is graphically described using simultaneous two-dimensional targeted M-mode, Doppler echocardiographic, and high-fidelity pressure recordings.

Blood Pressure↗

PubMedDate not supplied

Statistical shape model based segmentation of medical images.

This paper reviews several kinds of 2D shape representations by a set of parameters based on labeled points, Fourier descriptors and wavelet descriptors. Seven shape models for axial slices of spinal vertebra are derived by a statistical analysis of parameters corresponding to a set of example shapes and are subsequently compared. Two of the developed models are incorporated into methods for interactive segmentation of 2D gray level images. The first method is founded on Fourier descriptors, the second one is based on normalized sets of labeled points. Both methods are based on a model guided shape exploration.

Data Interpretation, Statistical↗

PubMedDate not supplied

Temporal coincidence of the appearance of elongated spermatids and of histochemical reaction of 11 beta-hydroxysteroid dehydrogenase in rat Leydig cells.

The serial semithin sections of the testes of perfused rats (age: 25-41 postnatal days) were evaluated microscopically on each alternative day for the morphology of spermatogenetic cells and especially for spermatid differentiation. The histochemical reaction for non-specific esterases, 3 alpha-hydroxysteroid-dehydrogenase (HSDH), 3 beta-HSDH, 11 beta-HSDH, 17 beta-HSDH were performed in cryostat sections of corresponding rat testes (age: 25-55 days). Eight different types of germ cell associations (designated as A-H) appeared from day 25 to day 41. Seven steps of differentiation of spermatids were characterized. The turning point of spermatid maturation was observed on day 35. Prior to this day, mainly spermatids step 1 were identified. On day 35 spermatids steps 1-5 were present. The reactions of non-specific esterases, 3 beta-HSDH, 17 beta-HSDH and 3 alpha-HSDH were observed in the Leydig cells of all testes. Only from day 35 onwards could 11 beta-HSDH be demonstrated. The temporal sequence of the differentiation of spermatids and the appearance of histochemical activity of 11 beta-HSDH in the Leydig cells seem to be closely correlated. An additional observation concerning the presence of germ cell debris was made in the seminiferous tubules during the postnatal development. Large amounts of debris were observed only till day 33.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMedDate not supplied

In utero development of pulmonary artery calcification in monochorionic twins: a report of three cases and discussion of the possible etiology.

Pulmonary artery (PA) calcification is unusual in children, reportedly occurring only in conjunction with severe underlying valvular disease. Three newborns were found by chest X-ray study to have thin calcified rings of the PA. Two were pump twins in twin reversed arterial perfusion (TRAP) sequences, each with an acardiac cotwin, and the third was the recipient in a twin transfusion syndrome (TTS). Both twin pairs with TRAP sequence were premature, each pump twin presenting with cardiac decompensation. One remained well at 5 months of age, the other died at 5 1/2 months of age. The third, the premature recipient of twins with TTS, died at 24 h of age, and the donor cotwin died at 2 h of age. The two hearts were structurally normal at autopsy. Subtle intimal wrinkling was seen above the pulmonary valve leaflets, and the media was yellow and granular on cut section. Hyperplasia of the intima and media with disruption and calcification of the elastic fibers of the media was seen microscopically. These three cases of PA calcification occurring in utero were not related to structural valvular abnormalities but were presumably due to increased cardiac output in utero as each occurred in the volume-overloaded twin of the twin pair. Comparison of the weight differences between these three twin pairs with PA calcification suggests a relationship between the presence of PA calcification and the severity of the cardiac volume overload. In utero cardiac damage may contribute to the high morbidity and mortality rate seen in infants with TRAP sequence and TTS.

Adult↗

PubMedDate not supplied

The preventive medicine manager: a new role for preventive medicine specialists in managed care.

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Education, Medical, Graduate↗