Interaction of antithrombin III and thrombin-antithrombin III complex with cultured aortic endothelial cells

The binding of antithrombin III, thrombin, thrombin-antithrombin III complex to endothelial cells was investigated. While the rate of the binding of thrombin to these cells was very rapid, that of antithrombin III was relatively slow and the thrombin-antithrombin III complex was intermediate. Binding kinetics indicated that antithrombin III, like thrombin, showed high affinity to endothelial cells; with a Kd of 3 X 10(-8) M and with 5 X 10(4) binding sites per cell. The dissociation of the inhibitor molecule was also rapid, i.e., approximately 70% bound antithrombin III was released in 2 minutes. Heparin, in a 100-fold molar excess to antithrombin III, or the modification of lysine residues of the inhibitor involved in the interaction with heparin, did not influence the association of antithrombin III with endothelial cells. In addition, antithrombin III did not compete with thrombin blocked in its active center for binding to endothelial cells. It is suggested that the binding sites of endothelial cells are different for thrombin and antithrombin III, and antithrombin III does not bind to these cells through its heparin binding domain.     

Traumatic rupture of hydatid cyst with unusual localization without liver involvement: a case report.

Primary hydatid disease of the intestinal mesentery is rare. We report on a 12-year-old male patient who presented with abdominal pain and urticaria lesions after blunt abdominal trauma. At laparotomy the cyst was found to be ruptured and was totally removed from the surrounding mesenteric tissue.The postoperative course was uneventful. This case is the first child reported with traumatic rupture of a hydatid cyst in a mesenteric location.     

Alternative complement pathway activation by Salmonella O polysaccharide as a virulence determinant in the mouse

The quality of Salmonella O polysaccharide (the O antigen) is a virulence factor in mouse salmonellosis. It affects the rate by which these bacteria are phagocytosed and by which they activate the alternative complement pathway in a manner inversely proportional to their virulence, suggesting that the rate of complement activation is crucial for the fate of the bacteria in the mouse. The effector mechanism has, however, remained open since Salmonellae survive and multiply in the macrophages of the mouse. We show in this study that although the least virulent O-6,7 Salmonellae multiply in the liver macrophages they are rapidly killed in the peritoneal cavity by the local resident macrophages. Electron microscopy showed a striking morphological feature--a 35 nm thick homogenous electron-dense deposit--on all the bacteria found in association with the macrophages but absent from all non-cell-associated bacteria. A similar precipitate was formed by incubating the bacteria in fresh mouse serum and was dependent on heat-labile serum components and bound anti-C3. The least virulent O-6,7 bacteria acquired this deposit more rapidly and in a lower concentration of serum than the more virulent O-4,12 bacteria consistent with the previously demonstrated difference between these bacteria in their rate of complement activation via the alternative pathway. Preincubation of the O-4,12 bacteria in fresh mouse serum leading to complement deposition on 80% of the bacteria effectively opsonized them for rapid killing in the peritoneal cavity. These data for the first time demonstrate how the rate of complement activation determines the virulence of Salmonellae.     

Comparative echocardiographic study of junior and senior basketball players

The echocardiographic data on 14 junior and 15 senior players in a first-division basketball club were compared. No difference was found between the senior and junior players as regards the thickness of the interventricular septum (11.47 vs 11.21 mm) or the thickness of the posterior wall of the left ventricle (9.8 vs 9.86 mm). The adults displayed a larger left ventricular end-diastolic diameter (56.8 vs 53.6 mm, P less than 0.05), end-diastolic volume (194 vs 164 ml, P less than 0.05), stroke volume (142 vs 116 ml, P less than 0.05), right ventricular diameter (27.9 vs 23.2, P less than 0.01), aortic root diameter (35.0 vs 32.0, P less than 0.05), and left atrial diameter (42.7 vs 37.2, P less than 0.01). However, among these, only the stroke volume and right ventricular diameter remained significantly different after normalization to body surface area. A significant difference could not be demonstrated in the linear ejection fraction, the ejection fraction, or the fractionated interventricular septum and posterior wall thicknesses. The examinations indicated that left ventricular hypertrophy had fully developed by the age of 18 years in the basketball players and that there was no further enhancement in adults. However, the left ventricular, right ventricular, and left atrial volume were larger in the adults than in the junior players.     

Why Do Supportive Birth Attendants Become Directive of Maternal Bearing-Down Efforts in Second-Stage Labor?

A supportive approach to care for women during the second stage of labor that primarily relies on the laboring woman's involuntary expulsive urges has been advocated. We aimed to learn about the clinical circumstances surrounding the caregiver shift from being primarily supportive to directing women regarding their bearing-down efforts. This research analyzed the communications of 10 birth attendants and women during the expulsive phase of labor using videotapes recorded from two studies carried out between 1986 and the present. The occasions when a birth attendant shifted verbalizations were identified, and categories of the rationales that may have influenced the modification in caregiver behavior were developed. Birth attendants most frequently provided directions to help the woman push effectively, that is, to focus the woman's bearing-down efforts during maternal distress, fatigue, fear, and pain to expedite the labor process (38% of the occasions of caregiver change in verbalizations). The next most frequent clinical situations when caregivers offered directions about "pushing" were diminished urge to bear-down with epidural analgesia (10%), routine arbitrary practices (9% caregiver and 6% by supportive companion), and fetal distress (<1%). A category of "supportive direction" (20%) was identified. This care strategy has not been previously reported. It combined direction with support in a way that was supportive rather than overriding the woman's involuntary efforts.     

Examination of lymph and bile composition following experimental liver transplantation in rat

The lymph flow of the thoracic duct, the protein content of the lymph, bile flow and bile composition are studied during the first three hours of the recirculation phase in experimental liver transplantation. It is established that the lymph flow and the protein content of the thoracic duct decrease as a result of the interruption of hepatic lymph flow of a high protein concentration. The change in bile composition and flow is due to the reduced bile acid excretion of the transplanted hepatic tissue.     

Effects of MR imaging on murine natural killer cell cytotoxicity

To determine the effect of MR imaging on the immune system, 21 male C57BL/6 X DBA/2 F1 mice were exposed to MR imaging at a field strength of 0.15 T for 2 hr. Another nine mice (controls) were sham exposed for the same amount of time. Mice were sacrificed and their spleens removed 24, 72, and 144 hr after the exposure (MR or sham). Spleen cell suspensions were passed over nylon wool columns and then used as effector cells in a short-term natural killer cell cytotoxicity assay with 51Cr-labeled YAC-1 cells as target cells. The results showed no evidence of decreased cytotoxicity due to exposure to MR. On the contrary, at all three times after exposure and for all target-to-effector cell ratios, mean cytotoxicity was greater for MR-exposed groups than for sham-exposed groups. The results show that MR exposure has no adverse effect on the immune system, as evidenced by natural killer cell activity.