香菇深层发酵产物的毒性研究

食用菌的深层发酵研究国内始于1980年，而用于系列保健食品方面刚刚起步。为对香菇的发酵产物应用安全性提供依据，按国家卫生部有关规定，以Wistar种大、小白鼠进行了毒性试验。LD_(50)＞20g/kg；20天蓄积试验无剂量-反应关系，解剖未见靶器官病理改变；微核仅称豪-杰氏小体，与溶媒蒸馏水作用近似；姐妹染色单体互换和Ames试验未出现致突变作用。综上结果认为香菇发酵产物是安全的，可供食品保健应用。     

Nonrandom X-inactivation patterns in normal females: lyonization ratios vary with age

The utility of X-inactivation based clonality assays for evaluation of human neoplasia is well-documented. However, excessive Lyonization is a potential limitation of these assays, because it mimics clonal derivation of cells. The incidence of excessive Lyonization in healthy females is controversial, with reported incidence varying from 4% to 33%. Several explanations have been offered for the observed variation, including different criteria for excessive Lyonization, diversity of X- linked clonality assays, small population sizes and more recently, tissue specificity of X-inactivation patterns. However, it is also possible that stem cell depletion, clonal hematopoiesis, or selection pressures on blood cells results in an increased incidence of excessive skewing. If any of the latter is true, then the incidence of excessive skewing should increase with age in blood cells. To test this hypothesis, we determined X-inactivation ratios at the human androgen receptor locus of 295 normal females from three age groups: (1) neonates, (2) females 28 to 32 years old and, (3) females aged > or = 60 years. The incidence of skewing (allele ratios > or = 3:1) was 8.6% (14 of 162) in neonates (P = .104 v 28 to 32); 16.4% (11/67) in 28 to 32 y.o. (P = .0064 v > or = 60), and 37.9% (25 of 66) in women > or = 60 y.o. (P < .0001 v neonates). When a more stringent criterion for skewing was used (allele ratios > or = 10:1), the incidence was 1.9% (3 of 162) in neonates (P = .362 v 28 to 32), 4.5% (3 of 67) in 28 to 32 y.o. (P = .0022 v > or = 60), and 22.7% (15 of 66) in > or = 60 y.o. group (P < .0001 v neonates). Results have been confirmed at the phosphoglycerate kinase locus for 48 heterozygous females. The incidence of excessive skewing increases with age. In neonates, the incidence is low and may correspond to true excessive Lyonization. Acquired skewing occurs with aging in normal females and is present in 38% of females over the age of 60. Further studies are needed to determine whether acquired skewing is a consequence of stem cell depletion, true clonal hematopoiesis, growth advantage conferred by parental-specific X-chromosomes, or other causes. These data provide an explanation for variation in reported incidence of excessive skewing in normal females. Furthermore, these findings suggest that any study of clonality using X-inactivation based assays should incorporate age- matched controls for Lyonization.     

MR imaging in infants with airway obstruction: preliminary observations

Magnetic resonance (MR) imaging of the trachea and main bronchi was performed in seven infants (aged 3-15 months) with symptoms of airway obstruction. Diagnoses made clinically, radiologically, and by transnasal flexible fiberoptic endoscopy included vascular ring (one patient), tracheal compression by the innominate artery (five patients), and tracheomalacia (one patient). MR images in sagittal and axial sections clearly demonstrated tracheal compression at the level of the innominate artery in three infants and tracheal narrowing due to a vascular ring in one patient. The other three patients had airway narrowing apparently unrelated to aberrant vascular structures on MR images. The appearance of the airways on MR images corresponded closely to endoscopic observations. It is concluded that MR imaging is capable of demonstrating airway obstruction in infants and delineating any relationship to major mediastinal blood vessels.     

ROLE OF INOSITOL-1-PHOSPHATASE INHIBITION IN THE MECHANISM OF ACTION OF LITHIUM

Abstract: Li inhibition of noradrenergic adenylate cyclase may be due to inhibition by Li of agonist-induced increases in GTP binding to G-protein. Such inhibition by Li of G-protein function could have effects on phosphatidyl- inositol-mediated second messenger systems as well as on cyclic AMP-mediated systems. However, Sherman, Berridge and others have proposed that Li affects phosphatidylinositol metabolism by inhibiting inositol-1-phosphatase. We recently have been able to measure inositol-1-phosphatase in human red blood cells. Preliminary data on patients treated with Li compared with, controls suggests that the enzyme is indeed inhibited in vivo in patients undergoing Li treatment. However, a series of experiments in rats on addition of inositol to Li treatment did not find that inositol could reverse Li effects. Chronic oral high dose inositol does not reverse Li-induced polyuria (measured by polydipsia), Li-induced weight loss or Li-induced depression of exploratory behavior. These results suggest that Li inhibition of inositol-1-phosphatase indeed occurs in vivo . However, the physiological significance of inosltol-1-phosphatase inhibition is not yet established.     

Variation in the thickness of the diaphragmatic crura with respiration

Misinterpretation of the diaphragmatic crura on axial computed tomography images is a recognized pitfall in diagnosis. The right diaphragmatic crus is generally longer and thicker than the left. The authors observed a case in which the left crus was thicker than the right, causing diagnostic difficulty. Obtaining scans at full expiration and full inspiration clarified the situation. Confirmation of respiratory variation in crural thickness was obtained in ten patients. The crura increased in thickness on inspiration, compared with the size on expiration.     

Hidden risks for pneumonia in Malawi

Domestic smoke exposure and early HIV infection are critical but unseen risk factors for pneumonia. This paper reviews how recent research in Malawi and elsewhere contributes to an understanding of the possible immunological mechanisms underlying these risks.     

Colorectal carcinoma: detection with indium-111 anticarcinoembryonic- antigen monoclonal antibody ZCE-025

A phase I and II clinical trial with indium-111-labeled anticarcinoembryonic-antigen monoclonal antibody ZCE-025 (In-111 ZCE-025) was initiated. Fifteen patients with colorectal tumors underwent external scintigraphy following the administration of 5.5 mCi (203.5 MBq) In-111 ZCE-025 at doses of 2.5-80.0 mg. Eighteen of 20 documented tumor sites, excluding those in the liver, were detected with In-111 ZCE-025. Lesions less than 1.5 cm could not be detected. Twenty-five percent of liver metastases exhibited positive accumulation of In-111 ZCE-025 at doses of 40-80 mg. No side effects were encountered. Because of the high detection rate of lymph node metastases from colorectal carcinoma with In-111 ZCE-025, this technique may be helpful in preoperative staging of patients with colorectal tumors, as well as in distinguishing recurrent tumors from postoperative or postradiation changes seen on computed tomography scans or other radiologic images.