Osteosarcoma of the nude rat. A model for experimental magnetic resonance imaging studies of bone tumors.

A 144cerium-induced osteosarcoma was transplanted to athymic nude rats (Han:rnu/rnu). Nineteen of the tumor-bearing animals were used to demonstrate the characteristics of the osteosarcoma on magnetic resonance imaging (MRI) in comparison with a group of nine animals that had not received any tumor transplant. The tumor-free animals showed homogeneous results in the measurements of their lower legs (T1, 800-898 mseconds; T2, 33-45 mseconds). The osteosarcomas of the tumor-bearing rats were clearly demonstrated and delineated from adjacent structures by MRI at tumor volumes between 0.3 and 7.5 cm3. A significant increase in T1 and T2 relaxation times was found, which corresponded to the increase in tumor volume. T1 relaxation times decreased slightly when tumor volumes reached greater than 5 cm3, whereas T2 relaxation times remained constant at tumor volumes greater than 2.5 cm3. Histologic changes in the structure of the tumors, occurring naturally during their growth, were proven by immersion-fixed sections embedded in paraffin and stained with hematoxylin-eosin. The water content of small and large tumors was determined by lyophilization and heat drying. Both histologic changes and differences in water content were reflected in the variations of relaxation times.     

In-vivo studies on Haemaccel-fibronectin interaction in man

An enzyme-linked immunoassay has been recently set up for direct measurement of the binding capacity of plasma fibronectin to gelatin. This binding capacity could be completely inhibited in vitro by an eight-fold excess of gelatin, of Haemaccel, but not of Geloplasma. On the contrary, the levels of immunoreactive fibronectin measured by laser nephelometry did not change, in presence of 10 to 1000 micrograms ml-1 of gelatin, of Haemaccel or of Geloplasma. When infused into normal volunteers, Haemaccel provoked a strong and immediate inhibition of the plasma fibronectin binding capacity to gelatin. This inhibition was dose-dependent and maximal after infusion of 500 ml of Haemaccel. Twenty-four hours after this infusion, there was a progressive recovery of the gelatin-binding capacity, which was almost completely achieved 96 h later. The formation of complexes between Haemaccel and fibronectin was demonstrated by gel filtration chromatography and by affinity chromatography. Immunoreactive plasma fibronectin levels remained unchanged up to 24 h after infusion of 500 ml of Haemaccel. A transient decline to 50% of its initial value then occurred the second day after the infusion. Therefore, a delay existed between the formation of fibronectin-Haemaccel complexes and their elimination from the bloodstream. This delay decreased when smaller volumes of Haemaccel were infused, which strongly suggests that plasma fibronectin is cleared by means of Haemaccel and does not seem to play a role of opsonin in these conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Factors influencing results of femoropopliteal bypass operations for lower limb ischemia

An ideal way to assess the effectiveness of femoropopliteal bypass procedures is to standardize patient- and surgeon-related variables by randomization. Through statistical analysis of multiple factors influencing patency, limb loss, death rate and hospital stay, the authors reviewed retrospectively 136 bypass procedures performed over 5 years. Variables that contributed significantly to the results were: preoperative symptoms (p = 0.037), graft material used (p = 0.016), age of the patient (p = 0.007), adequacy of runoff (p = 0.041) and smoking postoperatively (p = 0.013). Autogenous vein grafts were superior to prosthetic grafts, the cumulative patency at 5 years being 67.5% and 38.2% respectively. The authors emphasize that all patients needing vascular surgery should be advised to stop smoking, since in this study postoperative smoking increased the probability of limb loss and adversely affected the cumulative patency rate by interaction with other variables such as preoperative symptoms, graft material and age.     

Combined Excimer Laser and Topical Tacrolimus for the Treatment of Vitiligo: A Pilot Study

Background. Vitiligo is an acquired skin disorder that is characterized by well-defined, often symmetric white patches. Although current therapeutic modalities are directed toward increasing melanocyte melanin production, few treatment modalities address the immunologic nature of the disease.
Objective. To determine whether excimer laser, a known therapeutic modality, in combination with tacrolimus, a topical immunomodulator, accelerate response time and/or improve the degree of response in patients with this disorder.
Methods. Eight subjects diagnosed with vitiligo were recruited to participate in this institutional review board–approved double-blind, placebo-controlled study. Twenty-four symmetric vitiliginous patches (elbows, knees) from eight subjects received excimer laser treatment three times per week for 24 treatments or 10 weeks. Additionally, topical tacrolimus 0.1% ointment (Protopic) and placebo (Aquaphor) were applied to randomized patches (left or right) twice daily throughout the length of the trial. Vitiliginous patches were monitored with photographs at baseline, every 2 weeks, and 6 months after treatment. Biopsies were performed on subjects with significant results.
Results. Twenty vitiliginous patches from six subjects qualified for evaluation. Fifty percent of patches treated with combination excimer laser and tacrolimus achieved a successful response (75% repigmentation) compared with 20% for the placebo group. Subjects who responded successfully repigmented faster (19%) with combination therapy compared with excimer laser alone. Additionally, three subjects experienced transient hyperpigmentation in lesions treated with combination therapy.
Conclusion. Combining topical immunomodulators with known phototherapeutic modalities may represent a key advancement in the treatment of disease.     

Reductions in depressed mood and denial coping during cognitive behavioral stress management with hiv-positive gay men treated with haart

Background: Stress management interventions for HIV-positive persons have been designed to enhance coping skills and encourage health-promoting behaviors with the hope of decreasing distress and slowing disease progression.Purpose: We examined the efficacy of a cognitive behavioral stress management (CBSM) intervention in combination with medication adherence training (MAT) in 130 gay and bisexual men living with HIV infection.Methods: Participants were randomized to either a 10-week CBSM+MAT intervention (n = 76) or a MAT-only condition (n = 54). Measures of self-reported adherence, active cognitive coping (i.e., acceptance and positive reinterpretation), avoidant coping (i.e., denial and behavioral disengagement), and depressed mood were examined over the 10-week intervention period.Results: Men in CBSM+MAT reported reductions in depressed mood and denial coping during the 10-week intervention period, but no changes in active cognitive coping or self-reported adherence were observed. Using path analysis, greater reliance on denial coping at baseline was associated with decreased depressed mood at 10 weeks. We also determined that CBSM+MAT may decrease depressed mood by reducing reliance on denial coping over the 10-week intervention period.Conclusions: Although denial may be an effective means of distress reduction in the short term, reliance on this coping strategy may result in a decreased capacity to effectively manage a variety of disease-related stressors in the long term. CBSM+MAT addresses this potentially detrimental pattern by teaching stress reduction skills that may decrease depressed mood via reduced reliance on denial coping. This research was supported by National Institute of Mental Health Grants P01 MH49548 and T32 MH18917.     

A prospective investigation of pulmonary embolism in women and men.

OBJECTIVE. The aim of this study was to compare, in women and men suspected of pulmonary embolism, the frequency, risk factors, diagnosis, and presentation of pulmonary embolism as well as the accuracy of the ventilation/perfusion scan (V/Q scan) as a diagnostic tool. DESIGN. Data were collected during a prospective study (the Prospective Investigation of Pulmonary Embolism Diagnosis) to establish the accuracy of the V/Q scan compared with pulmonary angiograms. SETTING. Six tertiary medical centers in Massachusetts, Michigan, Connecticut, Pennsylvania, and North Carolina. PARTICIPANTS. Patients suspected of pulmonary embolism for whom a request was made for a V/Q scan or pulmonary angiogram (496 women and 406 men). RESULTS. Women 50 years old and under had a decreased frequency of pulmonary embolism compared with men of that age (16% vs 32%), but there was no difference in patients over 50 years old (Breslow-Day test, P less than .01). Risk factors for pulmonary embolism, the usefulness of the V/Q scan, and 1-year mortality were not different for women and men. Estrogen use in women was not associated with an increased frequency of pulmonary embolism, except in women using oral contraceptives who had undergone surgery within 3 months; four of five (80%) had emboli compared with four of 28 (14%) age-matched surgical patients not using estrogens (P less than .01). CONCLUSION. Women 50 years old and under (even young women using oral contraceptives) who were suspected of having pulmonary emboli and were enrolled in the Prospective Investigation of Pulmonary Embolism Diagnosis study had a smaller frequency of pulmonary embolism than men of that age, The risk factors for pulmonary embolism were the same for women and men, except that women using oral contraceptives had an increased risk of pulmonary embolism following surgery. Although the V/Q scan was a useful tool in the preliminary evaluation for pulmonary embolism in these women, a pulmonary angiogram was often needed for accurate diagnosis.     

Inhibitory motor control in children with attention-deficit/hyperactivity disorder: event-related potentials in the stop-signal paradigm.

BACKGROUND: The aim of the study was to investigate the inhibitory control of an ongoing motor response and to identify underlying neural deficiencies, manifested in event-related potentials, that cause poorer inhibitory performance in children with attention-deficit/hyperactivity disorder. METHODS: A stop-signal paradigm with a primary visual task and auditory stop signal was used to compare performance in 13 children with attention-deficit/hyperactivity disorder and 13 control children, while event-related potentials were recorded simultaneously. RESULTS: Children with attention-deficit/hyperactivity disorder showed poorer inhibitory performance through a slower inhibitory process. Inhibitory processing of auditory stop signals was marked by a frontal N2 component that was reduced in the attention-deficit/hyperactivity disorder group relative to controls. A central positive component (P3) was associated with the success of inhibiting a response, but there were no group differences in its amplitude or latency. CONCLUSIONS: Findings support the hypothesis of deficient inhibitory control in children with attention-deficit/hyperactivity disorder. Slower inhibitory processing appears to be due to a specific neural deficiency that manifests in the processing of the stop signal as attenuated negativity in the N2 latency range.     

Moderate head injury: a guide to initial management.

The purpose of this study is to determine the initial treatment of patients who appear to have sustained moderate head injuries when first evaluated. The authors reviewed the records of 341 patients whose initial Glasgow Coma Scale (GCS) scores ranged from 9 to 12, as well as another 106 patients with GCS scores of 13. All patients underwent cranial computerized tomography (CT) at the time of admission. In 40.3% of these patients the CT scans were abnormal (30.6% had intracranial lesions), and 8.1% required neurosurgical intervention (craniotomies for hematoma in 12, elevation of depressed fractures in five, and insertion of intracranial pressure monitors in 19). Four patients died of their intracranial injuries. A similar incidence of lesions found on CT and at surgery suggests that an initial GCS score of 13 be classified with the moderate head injury group. Skull fractures were found to be poor indicators of intracranial abnormalities. These results suggest that all patients with head injury thought to be moderate on initial examination be admitted to the hospital and undergo urgent CT scanning. Patients with intracranial lesions require immediate neurosurgical consultation, surgery as needed, and admission to a critical-care unit. Scans should be repeated in patients whose recovery is less rapid than expected and in all patients with evidence of clinical deterioration; this was necessary in almost half of the patients in this group, and 32% were found to have progression of radiological abnormalities on serial CT scans.     

Similar co-stimulation requirements of CD4+ and CD8+ primary T helper cells: role of IL-1 and IL-6 in inducing IL-2 secretion and subsequent proliferation.

Primary murine CD4+ and CD8+ T helper (Th) cells provide help for various immune responses by secreting lymphokines which activate effector cells. The purpose of the present study was to investigate the co-stimulatory signals that, together with T cell receptor (TCR) cross-linking, induce phenotypically distinct primary Th cells to secrete IL-2 and proliferate. We isolated highly purified populations of primary CD4+ or CD8+ T cells and stimulated them in vitro with platebound anti-CD3 mAb. TCR cross-linking by anti-CD3 mAb induced both IL-2 receptor expression and responsiveness to exogenous IL-2, but was not sufficient to induce either IL-2 secretion or T cell proliferation. Rather, for both CD4+ and CD8+ primary Th cells, IL-2 secretion and proliferation required both TCR cross-linking and antigen presenting cell (APC)-derived co-stimulatory signals. Based on G-10 adherence and sensitivity to gamma-irradiation, the APC populations able to induce primary CD4+ Th cells and primary CD8+ Th cells to secrete IL-2 were indistinguishable. In addition, we found that either IL-1 or IL-6 could replace the requirement for APC-derived co-stimulatory signals for IL-2 secretion and proliferation by both primary CD4+ Th cells and primary CD8+ Th cells. Thus, the present study has examined and compared the co-stimulatory requirements of rigorously purified subsets of IL-2-secreting primary CD4+ and primary CD8+ T cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical considerations in bypassing coronary arteries with 100% proximal occlusion.

Objective data on the ability of cineangiography to predict the size of reconstituted totally occluded coronary arteries, as well as the clinical outcome of such revascularization, are sparse. Accordingly, we reviewed 200 consecutive cases of coronary revascularization to determine the answers to these questions. Group I patients (n = 57, with 86 totally occluded coronary arteries) had at least one coronary artery with a 100% proximal occlusion that reconstituted distally. Group II patients (n = 143, with 205 subtotally occluded coronary arteries) had 50% to 99% proximal stenosis of at least one coronary artery. Cineangiograms were blindly reviewed to measure the size of the coronary arteries, which were compared with the actual vessel size at operation. In group I, the totally occluded coronary arteries had a cineangiographic size of 1.9 +/- 0.7 mm and an actual size of 1.6 +/- 0.4 mm (p = 0.00004). In group II, the subtotally occluded coronary arteries had a cineangiographic size of 1.8 +/- 0.4 mm compared with an actual size of 1.8 +/- 0.3 mm (p = not significant). The site of bypass grafting was significantly smaller in group I (1.6 +/- 0.4 mm versus 1.8 +/- 0.3 mm; p = 0.00008). The two groups were similar with respect to preoperative and intraoperative parameters. Operative mortalities were similar (group I, 1.8%; group II, 3.5%; p = 0.68). Creatine kinase isoenzyme profiles and electrocardiographic changes were similar, except for a significant late rise of creatine kinase-MB in group I (56.1 +/- 14.7 versus 30.7 +/- 33.7 MIU/mL; p < 0.001). In conclusion, cineangiography significantly overestimates the size of totally occluded coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)