Trends in spatial disorientation research.

Trends in spatial disorientation (SD) research over the past six decades were assessed by means of a literature review using four databases and three SD-related search terms. 347 SD-related papers were identified, 37% of which were in three categories: attitude displays, SD training, and SD incidence. The most dramatic trend was a marked upswing in SD research in the 1990's.     

Prostaglandins and angioplasty. An experimental study in canine arteries

To prevent platelet aggregation following percutaneous transluminal angioplasty (PTA), cyclooxygenase inhibitors such as acetylsalicylic acid (ASA) and indomethacin are recommended. However, ASA blocks both the proaggregating effects of thromboxane (TXA2) and the antiaggregating and vasodilating effects of prostacyclin (PGI2). The authors measured the contractile response of dilated canine carotid arteries in situ and in vitro using an isometric force transducer. Following PTA, contraction of the arterial wall was significantly reduced (p less than 0.01). By blocking cyclooxygenase with indomethacin (3 micrograms/ml), contraction was greatly improved (p less than 0.001). These results suggest that PTA may result in marked release of prostacyclin by the damaged arterial wall, which could account for the decreased responsiveness of the artery to exogenous norepinephrine.     

Percutaneous extraction of urinary calculi: use of the intercostal approach

The authors achieved successful percutaneous extraction of urinary calculi via an intercostal approach in 24 patients. In one patient, a large hydrothorax developed and thoracentesis was required; 2 patients had moderate and 6 minimal pleural fluid collections which did not require treatment. No patient had pneumothorax. Intercostal puncture provides direct access to the upper and middle poles of the kidney when they lie above the twelfth rib and subcostal angulation is not feasible. Such an approach is advantageous for stones in the ureter, as well as renal stones which are inaccessible from the lower pole. Fluoroscopy should be performed when planning the puncture in order to avoid the lung, and a working sheath is recommended.     

Fibrosing alveolitis: CT-pathologic correlation

Computed tomography (CT) was performed within 10 days of open lung biopsy in nine patients with fibrosing alveolitis. One-centimeter collimation contiguous scans through the chest were obtained in all patients. Additional 1.5-mm collimation scans were obtained in the area in which lung biopsy was later performed in six patients. In seven patients, CT demonstrated patchy involvement of the lung parenchyma, areas with a reticular pattern being intermingled with areas of normal lung. The reticular pattern was associated with cystic spaces 2-4 mm in diameter and was more severe in the lung periphery. Histologically, the reticular pattern corresponded to areas of irregular fibrosis. One patient had diffuse honeycombing (2-20-mm cysts), and one had honeycombing only in the lung periphery. In all patients, CT clearly defined the architectural changes seen on open lung biopsy. These changes were much better seen on the 1.5-mm than on the 10-mm collimation scans. CT may be helpful in determining the pattern and distribution of lung involvement in patients with fibrosing alveolitis and in guiding the surgeon to the most appropriate area(s) for biopsy.     

The vasa vasorum and angioplasty

Interruption of flow in the vasa vasorum may lead to medial necrosis and aneurysm formation. The purpose of this study was to determine whether angioplasty produces significant alterations in the morphology or blood flow of the vasa vasorum of the dilated artery. The morphology of the canine vasa vasorum was studied before and after angioplasty; in a separate experiment vessel wall blood flow (VWBF) in canine carotid arteries was measured after angioplasty to determine whether physiologic regulation of the blood flow was disrupted by arterial dilation. No morphologic changes could be demonstrated in the vasa vasorum of the dilated artery; however, VWBF was increased by 1194 +/- 215% (mean +/- standard error, p less than 0.01) between 90 and 120 minutes after angioplasty. VWBF in the adjacent nondilated arterial segment was also increased (720 +/- 177% between 10-30 minutes, p less than 0.01) but returned toward normal after 60 minutes. Adenosine caused a "paradoxical" decrease in VWBF (p less than 0.05) of the dilated arterial segment while causing increased VWBF (p less than 0.05) in the thoracic aorta. Angioplasty appears to produce persistent hyperemia in the dilated arterial wall. A paradoxical response to adenosine suggests that vasa vasorum in the dilated arterial segment are maximally vasodilated. This may be due to mechanical disruption of vasomotor tone or to release of vasoactive substances.     

Hydrosalpinges adversely affect markers of endometrial receptivity

While in-vitro fertilization (IVF) was initially developed in women with tubal factor infertility, recent clinical studies have suggested that the presence of hydrosalpinges lowers implantation and pregnancy rates. We postulated that these hydrosalpinges cause impaired endometrial receptivity. A total of 103 women with hydrosalpinges were prospectively evaluated, and compared with 55 infertile and 44 fertile controls. All women had endometrial biopsies during the window of implantation, analysed by conventional histological criteria, and also stained for three integrin markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha vbeta3). Women with hydrosalpinges (cases) expressed significantly less of the alpha vbeta3 integrin compared with controls. There was no difference in expression of alpha1beta1 or alpha4beta1 among groups. A significantly greater number of cases had out of phase histology and missing alpha vbeta3 (type I defects) and absent integrin expression despite normal histological maturation (type II) defects, compared with controls. Of 20 women with impaired endometrial receptivity who were also biopsied after hydrosalpinx surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven percent of type I and 57% of type II defects were corrected postoperatively. Using markers of endometrial receptivity, this study demonstrates that inflammatory hydrosalpinges have an adverse effect on endometrial receptivity, which in some cases may be overcome by surgical treatment of the hydrosalpinx.