禁食和再喂养期间大鼠小肠胰岛素和胰岛素样生长因子-1受体的比较

胰岛素样生长因子-1（IGF-1）和胰岛素可能是肠道生长的重要调节因子。为了研究肠细胞萎缩和再生期间小肠IGF－1受体（IGF-IR）和胰岛素受体（IR），我们比较了禁食72小时和肠内再喂养24～72小时大鼠空肠IGF-IR和IR表达的指标。禁食引起肠萎缩，血浆胰岛素和IGF－1浓度降低以及空肠IGF-1信使RNA（mRNA）水平的明显降低，再喂养可逆转这些改变。禁食明显增加胰岛素与空肠特异性地结合，IR含量（达对照组的230％）和9．6kb和7．4kbIRmRNA转录本水平（分别达对照组的202％和218％）。再喂养时，这些IR指标迅速降到对照组水平。禁食时IGP-IR（用Scatchard分析）和IGF－1－RmRNA无明显的改变。再喂养后的前24小时间11-kbIGF－IRmRNA转录本明显增加（达对照组水平166％），IGF-IR数量增加3倍。我们的结论是：大鼠空肠的IR和IGF－IR受到不同营养物利用状态的调节。再喂养时空肠IGF－1和IGF－IR表达的向上调节表明，IGF作用途径在对肠内营养物产生肠道营养反应的过程中起作用。     

Augmentation of gamma-globin gene promoter activity by carboxylic acids and components of the human beta-globin locus control region

Butyric acid increases fetal hemoglobin synthesis in adult animals and in erythroid cells in culture and induces the gamma-globin gene promoter in transient expression experiments in K562 cells (McDonagh KT, Nienhuis AW, Blood 78:255a, 1992 [abstr, suppl 1]). We compared the effect of butyrate and other short-chain carboxylic acids in transient expression studies with K562 cells using an expression plasmid bearing a luciferase reporter gene driven by the normal human A gamma-globin gene promoter. Butyrate (4 carbons) increased the activity of the human A gamma-globin gene promoter up to 123 times. Marked augmentation of the normal gamma-promoter activity was also noted with 5-carbon valeric acid (up to 394 times) and 3-carbon propionic acid (up to 129 times). The branched isobutyric acid as well as phenylacetate showed less ability to increase promoter activity. Addition of the tandemly repeated AP-1/NF-E2 (AP) enhancer sequences from hypersensitive site 2 (HS2) of the locus control region (LCR) increased gamma-promoter activity up to 24 times. Addition of a nearby 16-bp conserved motif (CM) in HS2 (Safaya S, Rieder RF, Blood 78:146a, 1992 [abstr, suppl 1]) to the AP-containing plasmid construct further increased gamma-promoter activity. In the presence of butyrate, the plasmid bearing both the AP and CM sequences showed gene expression up to 477 times greater than that of the basal gamma-promoter-driven luciferase plasmid in the absence of inducer. A plasmid bearing the herpes simplex thymidine kinase promoter was also tested and gene expression was markedly increased by the same organic acids. MEL cells responded to butyrate, valerate, and propionate with induction of hemoglobin synthesis. Responses to isobutyrate and 6-carbon caproate required higher concentrations of the compounds. Thus, other short-chain organic acids as well as butyrate increase gamma-promoter activity in the transient expression system, and this activity can be further augmented by incorporating LCR elements into the expression vector. Nonglobin promoters also respond to the same carboxylic acids.     

Spinal cord compression due to metastatic disease: diagnosis with MR imaging versus myelography

To determine the efficacy of magnetic resonance (MR) imaging and myelography for the diagnosis of spinal cord compression due to metastatic disease, the authors prospectively examined 70 patients who had known or suspected spinal involvement by malignancy. Most MR examinations consisted of T1-weighted sagittal imaging of the entire spine, with additional sequences as needed for clarification. Extradural masses were found in 46 patients, 25 of whom had cord compression. For extradural masses causing cord compression, the sensitivity and specificity of MR imaging was .92 and .90, respectively, compared with .95 and .88 for myelography. For extradural masses without cord compression the sensitivity and specificity of MR imaging was .73 and .90, versus .49 and .88 for myelography. MR imaging was much more sensitive for metastases to bone (.90 vs .49), as expected. MR imaging is an acceptable alternative to myelography for diagnosing spinal cord compression and is preferable as a first study because it is noninvasive and better tolerated.     

Transesophageal drainage of mediastinal abscesses

Esophageal perforation with subsequent formation of a mediastinal abscess is a well-recognized clinical entity. Causes include perforation due to rigid and fiberoptic endoscopy, bouginage, breakdown of surgical anastomoses, and protracted vomiting. This disorder is associated with a high morbidity and, without intervention, a high mortality. In the past, surgery has been the treatment of choice. Although percutaneous drainage techniques have been used in some cases, they are frequently less attractive due to the location of the esophagus and its proximity to thoracic organs and vascular structures. In this study, eight abscesses caused by esophageal perforations were drained through a transesophageal route with minimal patient morbidity. These cases are presented with a discussion of the techniques and patient follow-up.     

Internal mammary lymphadenopathy in breast carcinoma: CT appraisal of anatomic distribution

Internal mammary lymph nodes are an important site of occult metastasis in clinically operable and recurrent breast carcinoma. Anatomic distribution of enlarged internal mammary nodes in patients with breast cancer was analyzed in a review of thoracic computed tomographic studies of 219 women with operable, advanced, or recurrent cancer. Enlarged nodes were observed in 45 patients (20.5%), 32 with unilateral and 13 with bilateral involvement. Mean nodal diameter was 1.95 cm (0.6-6.0 cm). Lymphadenopathy was limited to one anterior intercostal space in 43%, two spaces in 26%, three spaces in 22%, and four spaces in 9%. Solitary or dominant nodal enlargement was centered at the first space in 14%, second space in 60%, and third space in 26%. Isolated lymphadenopathy in the fourth or fifth spaces was not observed. Metastases to internal mammary nodes frequently occur at multiple levels and are most common in the second and third spaces. This finding concurs with current surgical practice when internal mammary nodes are sampled.     

Does a fall down a centile chart matter? The growth and developmental sequelae of mild failure to thrive

Fifty-two children aged 18 months who had fallen across two weight centile lines were compared to 52 controls. Five years after the initial study, 89% of these children were traced. At follow-up, four of the cases but none of the controls had been placed in care and cases were significantly shorter and lighter than controls. Reanalysis of the early weight data revealed that the screening criterion had been over-inclusive, identifying a majority with only borderline failure to thrive (FTT). Although the mean IQ was lower in the cases than in controls, the difference was not statistically significant. However, a significant association was found within the cases between severity of FTT and IQ. There was no difference in the number of behaviour problems reported. The use of a simple centile shift-based definition of FTT, while proving to be over-sensitive, has identified a subgroup of children who suffered adverse long-term cognitive outcomes.     

Perfusion thallium imaging of type I diabetes patients with end stage renal disease: comparison of oral and intravenous dipyridamole administration

Eighty patients with type I diabetes and end stage renal disease were prospectively evaluated for coronary artery disease with dipyridamole-thallium-201 scintigraphy and quantitative coronary angiography. Forty patients received dipyridamole orally, and 40 received it intravenously. The prevalence of coronary artery disease was 53%. There were no significant differences in the accuracy of the two dipyridamole tests (sensitivity = 85%, specificity = 85%, accuracy = 85% for the oral group; sensitivity = 86%, specificity = 72%, accuracy = 79% for the intravenous group). Combining the 80 patients into a single group gave a sensitivity of 86%, a specificity of 79%, and an accuracy of 83% for the detection of coronary disease. Although the accuracy of this test in this patient population was similar to that previously reported for other groups, the prevalence of disease was high and resulted in a low predictive value of a negative test (83%).