Further evidence of dopamine transporter dysregulation in ADHD: a controlled PET imaging study using altropane.

BACKGROUND: The dopamine transporter (DAT) is known to be a key regulator of dopamine, and recent studies of genetics, treatment, and imaging have highlighted the role of DAT in attention-deficit/hyperactivity disorder (ADHD). The findings of in vivo neuroimaging of DAT in ADHD have been somewhat discrepant, however. METHOD: Dopamine transporter binding was measured using a highly selective ligand (C-11 altropane) and positron emission tomography (PET). The sample consisted of 47 well-characterized, treatment-na?ve, nonsmoking, non-comorbid adults with and without ADHD. Additionally, control subjects had few symptoms of ADHD. RESULTS: Results showed significantly increased DAT binding in the right caudate in adults with ADHD compared with matched control subjects without this disorder. CONCLUSIONS: These results confirm abnormal DAT binding in the striatum of adults with ADHD and provide further support that dysregulation of DAT may be an important component of the pathophysiology of ADHD.     

Retention of "safe" blood donors. The Retrovirus Epidemiology Donor Study

BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors.     

SAS amplification in soft tissue sarcomas.

Gene amplification is an important mechanism of increased gene expression in a number of human solid tumors. We have recently identified and cloned sequences from a novel DNA amplification unit in malignant fibrous histiocytoma. The amplified sequences are derived from chromosome 12q13-14 and encode a gene designated SAS (sarcoma amplified sequence). In the present study, a series of soft tissue sarcomas was studied to characterize further the phenomenon of SAS amplification. Seven of 22 (32%) malignant fibrous histiocytomas and three liposarcomas contained SAS amplification. Strikingly, all of the tumors with SAS amplification occurred in central sites (i.e., in the abdominal or inguinal regions) rather than in the extremities (i.e., in the arms of legs). These observations demonstrate that SAS amplification occurs with a significant frequency in mesenchymal tumors and is particularly associated with abdominal disease.     

Platelet MAO activity and the cortisol response to dexamethasone in major depression

Previous studies have sometimes found a positive relationship between platelet monoamine oxidase (MAO) activity and dexamethasone nonsuppression in depressed patients. To assess this relationship in more detail, we examined the association between these two biological variables in unmedicated depressed patients. A positive correlation between platelet MAO activity and 8:00 AM serum cortisol levels following an overnight dexamethasone test (1 mg) was observed. The relationship between high and low platelet MAO activity (median split) and suppression of serum cortisol levels was also significant. These relationships were stronger in bipolar patients. Multiple regression revealed that postdexamethasone 8:00 AM dexamethasone levels and platelet MAO activity were independent predictors of the 8:00 AM cortisol levels following dexamethasone. The possibility that platelet MAO activity may be a peripheral marker of brain serotonergic activity which in turn may affect various aspects of the hypothalamo-pituitary-adrenal axis activity, is discussed. We also found that all nine depressed patients studied greater than or equal to 15 days after admission were suppressors. Platelet MAO activity, but not 8:00 AM pre- or postdexamethasone serum cortisol, was related to the severity of depression.     

Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.     

The symmetry of hip bone mineral density. A dual photon absorptiometry approach

Dual photon absorptiometry studies were performed on the hips of 23 patients to determine whether bone mineral density values obtained from one hip were indicative of the values in the contralateral hip of the ambulatory patient. The femoral neck, trochanteric, and Ward's triangle areas of both hips were analyzed. There were no significant differences between the right and left hip bone mineral density measurements in any of these three areas. Since the right and left hip readings were highly correlated, either hip may be used to evaluate osseous status.     

T-cell-mediated activation of macrophages

Functionally diverse subpopulations of macrophages and lymphocytes, a wide array of stimulatory signals, and an enormous effector repertoire of activated macrophages keeps this field dynamically active. We review new advances in the identification of cytokines that interact to activate macrophages, and in the discovery of effector molecules used by activated macrophages to destroy their targets.