Sex differences in the effects of 1-(m-trifluoromethylphenyl) piperazine and 1-(m-chlorophenyl) piperazine on copulatory behavior in the rat

Peripheral administrations of TFMPP (0.2- 1 mg/kg) or MCPP (1 mg/kg) facilitated lordosis behavior in female rats treated with estradiol benzoate, and had no effects in females primed with estradiol benzoate and progesterone. In contrast, TFMPP (1 mg/kg) and MCPP (1 mg/kg) inhibited copulatory behavior in male rats. It is concluded that there are sex differences in the effects of TFMPP and MCPP on copulatory behavior in the rat. Moreover, it is suggested that the effects of these drugs on copulatory behavior may be mediated by activation of 5-HT1B and/or 5-HT1C receptors, or by blockade of activity at 5-HT3 receptors.     

Release of soluble transferrin receptor from the surface of human leukemic HL60 cells

Information regarding transferrin (Tf) receptor degradation is largely incomplete. HL60 cells were shown to release to their growth medium a Tf-binding protein which could be immunoprecipitated by anti-Tf receptor monoclonal antibodies (MoAbs) B3/25 and OKT9. Soluble Tf receptor was detected in the medium within one hour of replating of cells, and its release was inhibited at 4 degrees C. The affinity of Tf for the soluble receptor released by cells (kd = 2.3 x 10(-10) mol/L) was slightly lower than its affinity for the detergent-solubilized cellular receptor (kd = 1.2 x 10(-10) mol/L). 125I-Tf internalized and released by cells subsequently bound to Tf receptor released by the same cells, and soluble Tf receptor in the conditioned medium (CM) inhibited 125I-Tf binding to intact cells. The soluble Tf receptor isolated from the CM was smaller (78,000 daltons) than the cell surface receptor (94,000 daltons) when analyzed by gel electrophoresis under reducing conditions. Isolated cell membranes readily released soluble receptor; however, this release could be blocked by protease inhibitors. The soluble Tf receptor may represent the extracytoplasmic domain of the cellular Tf receptor released from the surface of HL60 cells through proteolytic cleavage by a membrane-based protease.     

Pneumothorax and other lung diseases: effect of altered resolution and edge enhancement on diagnosis with digitized radiographs

Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).     

Evaluation of the postoperative breast.

With widespread use of mammography for breast cancer screening, the number of surgical procedures has also increased. Overlapping with radiographic signs of malignancy, including masses, areas of asymmetric density and architectural distortion, microcalcifications, and skin thickening, postsurgical changes may make mammographic evaluation difficult. After tumor excision and irradiation where breast alterations are more profound and prolonged, the task of distinguishing recurrent tumor from scarring or fat necrosis is even more challenging. Mammograms after breast conservation therapy for carcinoma or after cosmetic surgery require correlation with physical findings and the surgical procedures that were performed. Responses of tissue to lumpectomy and radiation, such as breast edema and skin thickening, are most pronounced 6 to 12 months after treatment, gradually resolving within 1 to 3 years. Carefully tailored mammographic studies will promote the dual goal of early detection of local tumor recurrence and avoidance of misinterpreting postoperative and irradiation changes as malignancy. Sequential examinations should begin with a postoperative preradiation mammogram for residual carcinoma, particularly when microcalcifications have been present, followed by the baseline postradiation examination at 6 months with the next study 6 months later (1 year after initial treatment). Mammograms of the treated breast may be performed at intervals of 6 months until radiographic stability has been recognized. Annual studies thereafter are suggested. The contralateral, unaffected breast should be evaluated mammographically according to screening guidelines or clinical concerns. Mammograms performed after cosmetic and reconstructive procedures should be correlated with the surgical techniques and clinical history. Modified views for silicone implants can maximize visualization of breast parenchyma. Ultrasonography is a useful complement to mammography in demonstrating the origin of a palpable mass either within the implant or the breast parenchyma. In reduction mammoplasty, distorted architecture, parenchymal bands, tissue redistribution, and fat necrosis should be recognized. After mastectomy, myocutaneous reconstruction may be performed. Masses that develop within flap reconstructions most frequently represent fat necrosis, which, when calcifying oil cysts are seen, may have a characteristic radiographic appearance.     

Sex differences in plasma cocaine levels and subjective effects after acute cocaine administration in human volunteers

Gender differences after acute cocaine administration have received little attention in spite of the fact that males and females respond differently to many drugs. Seven male and seven female occasional cocaine users received both an intranasal dose of cocaine hydrochloride (0.9 mg/kg) and placebo powder in a randomized order and reported subjective effects via an instrumental joystick device and various questionnaires. Blood samples were withdrawn at 5-min intervals to assess pharmacokinetic differences. Male subjects achieved the highest peak plasma cocaine levels (144.4 ± 17.5 ng/ml), detected cocaine effects significantly faster than females and also experienced a greater number of episodes of intense good and bad effects. Women studied during the follicular phase of their menstrual cycle had peak plasma cocaine levels of 73.2 ± 9.9 ng/ml, which was significantly higher than when they were studied during their luteal phase (54.7 ± 8.7 ng/ml), but there were no differences in their subjective reports of cocaine effects. In spite of the different cocaine blood levels and subjective effects, peak heart rate increases did not differ between males and females suggesting that women may be more sensitive than males to the cardiovascular effects of cocaine. These data suggest that there are significant gender and menstrual cycle differences in the response to acute intranasal cocaine administration and these differences may have implications for the differential abuse of this drug.This paper is dedicated to Xavier Lamas, MD, PhD, who lost his life while ascending Mt. Everest, August 1995     

Computed tomography of mediastinal collaterals in SVC syndrome

A patient undergoing treatment for abdominal lymphoma presented with a superior vena cava (SVC) syndrome. The presence of a wide mediastinum and "nodular" mediastinal densities on CT presented a diagnostic problem, necessitating thoracotomy. The thoracotomy was negative for tumor or infection. We believe that the presence of an indwelling catheter and mediastinal lipomatosis resulted in the SVC syndrome. The "nodular" densities represented an unusual set of mediastinal collaterals that must be distinguished from adenopathy.