The left paratracheal reflection

The left paratracheal reflection, which is found medial to the left subclavian artery reflection, was sought in 302 normal posteroanterior (PA) chest radiographs, 93 conventional chest tomograms, and 113 thoracic computed tomographic (CT) scans. The left paratracheal reflection was visible on 31% of normal PA chest radiographs. Conventional tomography and CT showed that this finding is produced by contact of the lung with the mediastinum anterior to the left subclavian artery. The CT scans studied showed that the left paratracheal reflection actually represents contact of the lung with left paratracheal mediastinal fat 94% of the time, with the proximal 1-2 cm of the lateral wall of the left common carotid artery 5% of the time, and with the left tracheal wall 1% of the time. A variety of entities may alter the left paratracheal reflection.     

Treatment of uterine leiomyomas with luteinizing hormone-releasing hormone antagonist Cetrorelix

The efficacy of the luteinizing hormone-releasing hormone antagonist Cetrorelix (SB-75) in the medical management of uterine leiomyomas (fibromas) was evaluated. Cetrorelix was administered to 18 pre- menopausal women with myomas with a mean age of 33.3 years, who had been candidates for hysterectomy. The initial dose of Cetrorelix was 5 mg twice daily s.c. for the first 2 days and thereafter 0.8 mg was given twice daily s.c. for at least 3 months. The mean duration of the treatment was 4.4 months. Before the therapy with Cetrorelix, the mean uterine volume, measured by ultrasonography, was 395.4 +/- 69.2 ml (range 89-1166). Sixteen patients showed a progressive reduction in uterine volume from 410.4 +/- 77.1 to a mean of 230.8 +/- 52.6 ml at 3 months. All patients became amenorrhoeic and had hot flushes. After treatment with Cetrorelix, a surgical myomectomy was performed in 12 women. One of the patients subjected to myomectomy after therapy with Cetrorelix became pregnant. These patients have been followed for up to 25 months and only in one case has the uterine volume increased after therapy. Three patients had good responses to therapy with Cetrorelix and it was decided to follow them only by observation. One patient became pregnant 2 months later. In the other patient, the uterine volume remained unchanged for the duration of the follow-up of 2 years and the third patient showed an increase after 21 months. In three patients, it was necessary to perform total hysterectomy. In 14 patients, serum concentrations of luteinizing hormone, follicle stimulating hormone and oestradiol decreased after the administration of the first dose of Cetrorelix and continued at subnormal values throughout therapy. In 15 patients who were not subjected to total hysterectomy, menstrual function returned at 1 month after cessation of treatment. Overall results support the use of Cetrorelix for the management of uterine leiomyomas.      

Hybrid imaging with 99mTc‐WBC SPECT/CT to monitor the effect of therapy in diabetic foot osteomyelitis

This study sought to assess the utility of monitoring response to treatment of diabetic foot osteomyelitis (DFO) with Tc‐99m WBC‐labelled single photon emission computed tomography (SPECT/CT) imaging. This is a retrospective cohort study of 20 patients with DFO with sequential Tc‐99m WBC‐labelled SPECT/CT imaging. Radiologic findings of osteomyelitis were evaluated and imaging results were correlated with clinical outcomes subtracted from chart review. Successful treatment of osteomyelitis was defined by wound healing and/or lack of re‐admission for bone infection of the same site within 1 year. The sensitivity, specificity, positive predictive value and negative predictive value of SPECT/CT to determine osteomyelitis treatment remission were 90%, 56%, 69% and 83%, respectively. Tc‐99m WBC‐labelled SPECT/CT imaging may be useful to help determine treatment outcomes for DFO.     

Rho kinase and protein kinase C involvement in vascular smooth muscle myofilament calcium sensitization in arteries from diabetic rats

Background and purpose:

Diabetes mellitus (DM) causes multiple dysfunctions including circulatory disorders such as cardiomyopathy, angiopathy, atherosclerosis and arterial hypertension. Rho kinase (ROCK) and protein kinase C (PKC) regulate vascular smooth muscle (VSM) Ca²⁺ sensitivity, thus enhancing VSM contraction, and up-regulation of both enzymes in DM is well known. We postulated that in DM, Ca²⁺ sensitization occurs in diabetic arteries due to increased ROCK and/or PKC activity.

Experimental approach:

Rats were rendered hyperglycaemic by i.p. injection of streptozotocin. Age-matched control tissues were used for comparison. Contractile responses to phenylephrine (Phe) and different Ca²⁺ concentrations were recorded, respectively, from intact and chemically permeabilized vascular rings from aorta, tail and mesenteric arteries.

Key results:

Diabetic tail and mesenteric arteries demonstrated markedly enhanced sensitivity to Phe while these changes were not observed in aorta. The ROCK inhibitor HA1077, but not the PKC inhibitor chelerythrine, caused significant reduction in sensitivity to agonist in diabetic vessels. Similar changes were observed for myofilament Ca²⁺ sensitivity, which was again enhanced in DM in tail and mesenteric arteries, but not in aorta, and could be reduced by both the ROCK and PKC blockers.

Conclusions and implications:

We conclude that in DM enhanced myofilament Ca²⁺ sensitivity is mainly manifested in muscular-type blood vessels and thus likely to contribute to the development of hypertension. Both PKC and, in particular, ROCK are involved in this phenomenon. This highlights their potential usefulness as drug targets in the pharmacological management of DM-associated vascular dysfunction.     

Surface antigenic determinants on human pluripotent and unipotent hematopoietic progenitor cells

RFB-1 is a monoclonal antibody previously shown to react with granulocyte-monocyte progenitors (CFU-GM) and immature lymphoid cells in human bone marrow. RFB-HLA-DR is a monoclonal antibody that reacts with HLA-DR (la-like) antigens. The present study shows that the bone marrow subset reactive with both RFB-1 and RFB-HLA-DR contains all the cells that give rise to mixed hematopoietic colonies (derived from CFU- GEMM; a pluripotent human progenitor cell) as well as to megakaryocytic (megakaryocyte-CFU-derived) and erythropoietic (derived from erythroid burst-forming units, BFU-E) colonies, as shown by fluorescence- activated cell sorting and complement-mediated cytotoxicity. These results indicate that CFU-GEMM, BFU-E, and megakaryocyte-CFU express RFB-1 and la-like antigens. RFB-1 antigen is also expressed on erythroid colony-forming units (CFU-E). RFB-1 and RFB-HLA-DR are useful reagents in the study of hematopoietic stem cells.