PET-CT在非完全实性肺结节中的应用价值

肺癌在中国恶性肿瘤的发病率位居第一,随着低剂量薄层CT在肺癌筛查中的广泛应用,临床发现更多表现为非完全实性结节的肺腺癌,目前众多研究使CT影像学特征和肺腺癌病理的关系得到更进一步的认知,虽然CT能对部分非完全实性结节做出定性和定位诊断,但仍有部分非完全实性结节诊断困难,PET-CT结合了病灶的代谢信息和精确的定位信息,从而提高对肺部结节诊断的敏感性、特异性、准确性,综合多个文献PET-CT在非完全实性结节中的诊断分期价值较CT无明显提升,却在评估预后和制定合适手术方案上可以起到一定的作用,本文就PET-CT在SSN中的应用价值进行阐述。     

Physiological control and process kinetics of clavine alkaloid production byClaviceps purpurea

Summary Kinetic parameters of production of clavine alkaloids were evaluated in twoClaviceps purpurea strains. Mutagenesis brought about enhanced resistance of the biosynthetic system towards alkaloids. Addition of glucose into the fermentation medium altered the zero order kinetics of production to activation-inhibition kinetics. The glucose treatment allowed performance of both elymoclavine-inhibitionless and clavine alkaloid-decompositionless fermentations if a combination of fermentation and separation units in a closed loop was used.Nomenlacture k ₁ rate constant of agroclavine synthesis (mg Agro · mg Elymo/l·g DW·day for stage 1, mg Agro/g DW·day for stage 2) - k ₂ parameter describing inhibition of agroclavine formation rate by elymoclavine (mg Elymo/l) - k ₃ specific rate of agroclavine decay (l/g DW·day) - k ₄ maximal specific rate of elymoclavine synthesis (stage 1, 1/g DW·day, stage 2, mg Elymo/g DW·day) - k ₄ ^– maximal specific rate of elymoclavine synthesis in stage 1 (inhibition-activation mechanism) (mg Elymo/g DW·day) - k ₅ physiological constant describing the elymoclavine decay rate (l²/g DW·day·mg Elymo) - k ₅ ^– physiological constant describing the activation of elymoclavine biosynthesis by elymoclavine (mg Elymo/l) - k ₆ physiological constant describing the repression of elymoclavine biosynthesis by elymoclavine (mg Elymo/l) - k ₇ maximal specific growth rate (1/day) - k ₈ specific rate of biomass decay (l/g DW·day) - A agroclavine concentration (mg/l) - E elymoclavine concentration (mg/l) - r _A specific rate of agroclavine biosynthesis (mg Agro/g DW·day) - r _E specific rate of elymoclavine biosynthesis (mg Elymo/g DW·day) - r _i specific rate of alkaloid biosynthesis (mg alkaloid/g DW·day) - X dry biomass concentration (g/l) - specific growth rate (1/day) Abbreviations Agro agroclavine - Elymo elymoclavine - Chano chanoclavine - DW dry weight of biomass     

烟青虫感染核型多角体病毒后围食膜的病变

昆虫的围食膜是衬在昆虫中肠内一种网状的结构,它可充作虫体抵御外来病原侵染的一道屏障。关于鳞翅目昆虫幼虫感染了昆虫病毒后围食膜的病变问题,国内外鲜有报道。尤锡镇和康慧娟(1985)曾以实验证明家蚕围食膜对核型多角体病毒有灭活作用,而且认为核型多角体病毒不能侵染和破坏围食膜。Derksen和Granados(1988)则证明染病幼虫的围食膜因不同杆状病毒(包括两种核型多角体病     

No correlation exists between the conjugative transfer of the autotrophic character and that of plasmids in Nocardia opaca strains

A new isolate of Nocardia opaca was obtained by enrichment culture for aerobic lithoautotrophic growth on CO2 and H2. This strain, MR22, is very similar to N. opaca MR11 (formerly 1b) in functioning as a donor for genetic information determining the ability to grow lithoautotrophically (Aut character) in matings with Aut- strains of N. opaca or closely related heterotrophic species. The strain contains a plasmid, pHG33 of about 110 kb. A mutant was isolated from strain MR22 which was plasmid-free, and had lost the Aut character, resistance to 50 microM-thallium salt and susceptibility to the nocardia-specific bacteriophage phi B1. As a recipient of the Aut character, this plasmid-free mutant was as well suited as plasmid-bearing Aut- strains of N. opaca. In matings with the mutant as recipient the frequency of Aut+ transconjugants per donor was 3 X 10(-4) with N. opaca MR11 (pHG31-a, Aut+, Tlr, Strs, phi B1s) and 2 X 10(-3) with N. opaca MR22 (pHG33, Aut+, Tlr, Strs, phi B1r) as donor. Phenotypic characterization of the transconjugants, which had been selected for the Aut marker, revealed that in many cases the Aut marker had been transferred without plasmid transfer. Furthermore, plasmid-free, Aut+ transconjugants functioned as donors for the Aut marker. Both plasmid-free and plasmid-bearing transconjugants transferred the Aut marker to the Aut- strains of N. opaca with a frequency which was one or two orders of magnitude higher than that of the wild-type strains. The plasmids pHG31-a and pHG33 code for thallium resistance (50 microM-thallium acetate). The frequency of thallium-resistant transconjugants was 10(-1) to 10(-2) per donor; all thallium-resistant transconjugants contained the donor plasmid. We conclude that the plasmids pHG31-a of strain MR11 and pHG33 of strain MR22 of N. opaca carry the genetic information for thallium resistance but not the Aut character. As plasmid-free Aut+ strains can function as donors the Aut character is assumed to reside on the chromosome and to function as an independent self-transmissible genetic element.     

Taxonomic studies on some gram-positive coryneform hydrogen bacteria

Recently isolated coryneform hydrogen bacteria were investigated under taxonomical aspects. Strains 7 C, RH 10, and 14 g are characterized by the snapping type of cell division, 68.5 to 69.7% GC content, dl-diaminopimelic acid in the cell wall, content of metachromatic granules, weak utilization of sugars and inhibitory effect of citrate. The strains are placed to the group 1—genus Corynebacterium—of the classification of coryneform bacteria of Yamada and Komagata (1972) and the name Corynebacterium autotrophicum sp.nov. is proposed.Strains 11 X and RH 12 are characterized by the bending type of cell division, a GC content of 70.2 and 70.5%, ll-diaminopimelic acid in the cell wall, absence of metachromatic granules, utilization of several sugars and no changes in cell morphology by citrate. The strains have to be placed to group 6 of coryneform bacteria.     

Mixed infection of Rickettsiella phytoseiuli and Coxiella burnetii in Dermacentor reticulatus female ticks: electron microscope study

Mixed infection of Rickettsiella phytoseiuli and Coxiella burnetii was investigated in hemolymph and organs of experimentally infected females of Dermacentor reticulatus ticks. Following intracoelomic infection, both agents, with the exception of Gene's organ, multiplied well in the cells of the tick host's organs. Two out of six developmental stages of R. phytoseiuli, i.e., crystal-forming and small dark particles, in dual infection with C. burnetii revealed marked morphological alterations. C. burnetii in the presence of R. phytoseiuli penetrated into the cortical layer of the synganglion and into the alveoli of the second and third type of salivary glands, but did not occur in the single infection.     

Induction of differentiation of rat retinal, germinal, neuroepithelial cells by dbcAMP

Little is known about the factors that regulate the production of neurons during the development of the vertebrate central nervous system (CNS); however, evidence from several neuronal cell lines suggests that an increase in intracellular cAMP might trigger the process of differentiation. To determine if a similar process is involved in differentiation during normal CNS neurogenesis, we raised the intracellular level of cAMP in primary cultures of mitotically active, germinal neuroepithelial cells from fetal and postnatal rat retina. This treatment induced differentiation of the CNS precursors, causing the cells to cease DNA synthesis and increase their expression of proteins normally found in differentiated retinal cells. These results indicate that germinal neuroepithelial cell differentiation can be controlled through the cAMP second messenger system, and that the regulation of this system may in part determine the numbers and ratios of the various classes of neurons during the normal development of the CNS.     

Extracellular metabolism of sucrose in a submerged culture of Claviceps purpurea: formation of monosaccharides and clavine alkaloids

Transformation of extracellular sucrose during cultivation of Claviceps purpurea led to the formation of mono- and oligosaccharides. Maltose was a suitable substrate for submerged fermentation of alkaloids. Fermentation in a medium with maltose was characterized by an insignificant formation of glucans, intensive sporulation, suspension growth of mycelium, and a higher formation of elymoclavine. Glucose alone yielded low levels of total alkaloids and high glucan formation; on the other hand, glucose promoted the formation of elymoclavine.     

Somatoform disorders among patients attending walk-in clinics in Trinidad: prevalence and association with depression and anxiety

Objectives Somatoform disorders are common in international primary care settings, but have been little studied in the developing world. The objective of this study was to determine the prevalence of severe undifferentiated somatoform disorder, and its relationship to depression and anxiety, among patients attending walk-in clinics in Trinidad.Methods The study participants, who were all aged 18 years or older and attending walk-in clinics at 16 randomly selected health centres, were surveyed between May and August 2007 using the PRIME-MD questionnaire.Results There were 594 participants (the response rate was 92%), of whom 72.7% were female. Their ages ranged from 18 to 93 years, and 54.5% were over 50 years of age. In total, 37.2% were married and 25.9% were single. Indo-Trinidadians represented 43.1% and Afro-Trinidadians represented 36% of the study sample; 56.5% of the participants reported that their income was less than US$ 400 per month, and 65.7% were unemployed. At walk-in clinics in Trinidad, the estimated prevalence of severe undifferentiated somatoform disorder was 10.3% (95% CI: 7.86–12.74), that of hypochondriasis was 28.5% (95% CI: 24.9–32.1), and that of body dysmorphic disorder was 15.8% (95% CI: 11.9–18.7). Severe undifferentiated somatoform disorder was statistically significantly associated with gender and ethnicity but not with age, level of education, employment status or income. Chi-square testing found significant associations between the presence of severe undifferentiated somatoform disorder and both depression and anxiety (P < 0.05), between hypochondriasis and both anxiety and depression (P < 0.05), and between body dysmorphic disorder and depression (P < 0.05) but not anxiety. Regression analysis suggested that the demographic features that predicted severe undifferentiated somatoform disorder were being female or Indo-Trinidadian.Conclusions Walk-in clinics in Trinidad that serve older patients on a lower income have a high proportion of patients with somatoform disorders as measured by the PRIME-MD scale. These patients exhibit many features of anxiety and depression. These findings have implications for medical training and service delivery.