Design of a Modular Protein-Based MRI Contrast Agent for Targeted Application

Magnetic resonance imaging (MRI) offers a non-radioactive alternative for the non-invasive detection of tumours. Low molecular weight MRI contrast agents currently in clinical use suffer either from a lack of specificity for tumour tissue or from low relaxivity and thus low contrast amplification. In this study, we present the newly designed two domain fusion protein Zarvin, which is able to bind to therapeutic IgG antibodies suitable for targeting, while facilitating contrast enhancement through high affinity binding sites for Gd³⁺. We show that the Zarvin fold is stable under serum conditions, specifically targets a cancer cell-line when bound to the Cetuximab IgG, and allows for imaging with high relaxivity, a property that would be advantageous for the detection of small tumours and metastases at 1.5 or 3 T.     

Antiretroviral Therapy,Especially Efavirenz,Is Associated with Low Bone Mineral Density in HIV-Infected South Africans

Purpose

We determined the prevalence and correlates of low bone mineral density (BMD) in HIV-infected South Africans as there is a paucity of such data from Africa.

Methods

BMD and serum 25-hydroxyvitamin D were measured in HIV-positive participants on antiretroviral therapy (ART) and in those not yet on ART (ART-naïve).

Results

We enrolled 444 participants [median age 35(IQR: 30, 40) years; 77% women]. BMD was low (z score <-2SD) in 17% and 5% of participants at the lumbar spine and total hip, respectively. Total hip [0.909 (SD 0.123) vs 0.956 (SD 0.124) g/cm², p = 0.0001] and neck of femur BMD [0.796 (SD 0.130) vs 0.844 (SD 0.120) g/cm², p = 0.0001] were lower in the ART, compared to the ART-naïve group. Vitamin D deficiency was present in 15% of participants and was associated with efavirenz use [adjusted OR 2.04 (95% CI 1.01 to 4.13)]. In a multivariate linear regression, exposure to efavirenz or lopinavir-based ART was associated with lower total hip BMD, whereas higher weight, being male and higher vitamin D concentration were associated with higher total hip BMD (adjusted R² = 0.28). Age, weight, sex, and the use of efavirenz-based ART were independently associated with lumbar spine BMD (adjusted R² = 0.13).

Conclusions

Vitamin D status, use of efavirenz or lopinavir/ritonavir, weight, age and sex are significantly associated with lower BMD in this young cohort of HIV-infected South Africans.     

Low Serum 25-Hydroxyvitamin D Levels Are Associated with Dry Eye Syndrome

Background

Dry eye syndrome (DES) is a common tear film and ocular surface disease that results in discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. Systemic diseases associated with DES include diabetes mellitus, rheumatoid arthritis, depression, anxiety, thyroid disease, allergic diseases, irritable bowel syndrome, chronic pain syndrome, and hyperlipidemia. Interestingly, it has been found that most of these are associated with low levels of serum 25-hydroxyvitamin D (25(OH)D) or inadequate sunlight exposure.

Methods

In this cross-sectional data analysis, noninstitutionalized adults aged ≥19 years (N = 17,542) who participated in Korean National Health and Nutrition Examination Survey 2010–2012 were included. Information regarding duration of sunlight exposure was collected from the survey participants. Serum 25(OH)D and zinc levels were measured. The confounding variables were age, gender, sunlight exposure time, region of residence, obesity, serum 25(OH)D level, diabetes mellitus, rheumatoid arthritis, depression, thyroid disorder, atopic dermatitis, history of ocular surgery, regular exercise, and walking exercise.

Results

Mean serum 25(OH)D levels of subjects with and without DES were 16.90 ± 6.0 and 17.52 ± 6.07 (p<0.001). Inadequate sunlight exposure time (odds ratio [OR], 1.554; 95% confidence interval [CI], 1.307–1.848), urban residence (OR, 1.669; 95% CI, 1.456–1.913), indoor occupation (OR, 1.578; 95% CI, 1.389–1.814), and low serum 25(OH)D level (OR, 1.158; 95% CI, 1.026–1.308) were the risk factors for DES. After adjusting for age, sex, obesity, diabetes mellitus, rheumatoid arthritis, depression, thyroid disorder, atopic dermatitis, history of ocular surgery, regular exercise, and occupation, low serum 25(OH)D level (OR, 1.178; 95% CI, 1.010–1.372) and deficient sunlight exposure time (OR, 1.383; 95% CI, 1.094–1.749) were the risk factors for diagnosed DES.

Conclusion

Low serum 25(OH)D levels and inadequate sunlight exposure are associated with DES in Korean adults. These results suggest that sufficient sunlight exposure or vitamin D supplementation may be useful in DES treatment.     

Hydrogen Peroxide Content and Catalase Activity on Inoculation with Root Nodule Bacteria of Pea Seedlings with Different Ability for Nodulation

Hydrogen peroxide (H₂O₂) content and catalase activity were studied in pea (Pisum sativum L.) seedlings with a normal (cultivar Marat) and disrupted (pea mutants) process of nodulation that were inoculated with the nitrogen-fixing bacterium Rhizobium leguminosarum strain CIAM 1026. Differences in hydrogen peroxide content and catalase activity in pea seedlings with different ability for nodulation that were inoculated with rhizobia were found. It was assumed that H₂O₂ and catalase are involved in defensive and regulatory mechanisms in the host plant.     

Low Elastin Content of Carotid Plaques Is Associated with Increased Risk of Ipsilateral Stroke

Objectives

Atherosclerotic plaques with a low content of connective tissue proteins are believed to have an increased risk of rupture and to give rise to clinical events. The aim of the present study was to investigate if the content of elastin, collagen and of the matrix metalloproteinase (MMP) −1, −3, −9 and −12 in plaques removed at surgery can be associated with the occurrence of ipsilateral symptoms.

Methods

The atherosclerotic plaques of 221 patients undergoing carotid endarterectomy were analyzed and their composition was related to the incidence of preoperative, intraoperative and postoperative neurological events.

Results

Elastin, collagen and MMP-12 contents were lower in males and diabetic patients. Elastin (P .010), MMP-3 (P .008) and MMP-9 (P < .0001) were lower, while MMP-1 (P .004) and MMP-9 (P .002) were higher in plaques of patients with preoperative symptoms, even after correction for the time between the occurrence of symptoms and surgery. Elastin and MMP-12 decreased (r = −0.17, P .009 and r = −.288, P <.0001 respectively) while MMP-1 (r = 0.17, P .012) and MMP-9 (r = .21 P <.0001) increased with age. After a mean follow-up time of 39.6 ± 16.6 months, 7.7% of patients had suffered one or multiple ipsilateral neurological events. Patients with plaque elastin levels lower than the median (52 mg/g) had increased post-operative incidence of ipsilateral stroke (P for trend 0.009 using Log Rank Chi-square test). This finding was confirmed when controlling for age, gender, hypertension, diabetes, smoking, pre-operative symptoms and statin usage in a Cox Proportional Hazard model (hazard ratio 7.38, 95% C.I. 1.50–36.31).

Conclusions

These observations support the concept that elastin may be important for plaque stability, and suggest that a low plaque content of elastin is associated with a higher risk for ipsilateral stroke.     

低能Ti+注入棉花种子的深度-浓度分布的模拟计算

国内许多单位开展了低能离子注入植物种子的实验研究,但在生物诱变机理方面却尚未有定论,其中低能离子注入植物种子的深度-浓度分布成为研究的一个焦点问题.许多人直接用LSS理论得到的TRIM程序,从理论上计算了低能重离子注入植物种子的深度-浓度的分布,却发现计算结果与实验测量结果相差甚远,于是得出LSS理论及TRIM程序不能直接用于计算离子注入非均匀、非致密、有孔道的植物种子这种特殊的靶材料的结论.针对这一研究课题,在目前尚未有更加成熟完善的理论模型和计算方法的前提下,为了便于计算,本文根据植物种子的结构特点,对靶材料棉花种子进行了处理,并对LSS理论进行了修正,用蒙特卡罗方法计算了初始能量为20keV的Ti 注入棉花种子的深度-浓度分布,得到了与实验结果符合较好的分布曲线,初步的确定了低能离子注入植物种子深度-浓度分布的一种理论计算方法.     

Formation of a Tree having a Low Lignin Content

Received 30 September 2001/ Accepted in revised form 26 October 2001     

Extremely Low D/H Ratios of Photoproduced Hydrogen by Cyanobacteria

Cyanobacteria, having primary photosynthetic reactions similarto higher plants, are capable of producing large quantitiesof molecular hydrogen by nitrogenase and/or hydrogenase deliveringelectrons to hydrogen ions via ferredoxin or oxidation of NADPH.We measured the deuterium/hydrogen (D/H) ratios of the hydrogengas photoproduced by Synechococcus sp. Miami BG 043511 and Anabaenasp. TU 37-1, and demonstrate that D values of their hydrogengas are extremely low (about – 600%) when compared withthat of available water (–7%).This depletion gives a meanfractionation factor (a) of 0.43, which is similar to that calculatedfor hydrogen ions at equilibrium with water (0.35) and hydrogenproduced by electrolysis of water (0.24) but significantly differentfrom those of carbon bound hydrogens (>0.83). Thus hydrogenions available for protonation of NADP⁺ may be extremely deuteriumdepleted. Our results may explain why D/H ratios of nitratedcellulose or lipids from most plants are always depleted relativeto water available for photosynthesis. ³ On leave from School of Marine Science and Technology, TokaiUniversity, 3-20-1 Orido, Shimizu, 424 Japan (Received April 1, 1991; Accepted June 21, 1991)     

Polyethylene Glycol Embedment for Histological Studies of Bean Seed Testa of Low Moisture Content

Light microscopic examination of the structure of seed testa of snap and semihard bean seeds with 6% and 12% moisture contents in paraffin sections was unsuccessful because of poor paraffin infiltration and subsequent separation of subjacent and palisade cell layers. We devised an alternative method using polyethylene glycol (PEG) as the embedding material. Specimens were killed and fixed in the usual manner. They were then run up through a graded series (25, 50, 75, 100%) of PEG 1000 to PEG 1450, and finally embedded in a mixture of PEG 1450 and 4000 (19:1 by weight). Transverse and longitudinal sections retained excellent morphological detail and were suitable for histological study. Sections temporarily stained with 0.025% thionin allowed good quality photomicrographs.     

QUANTITATIVE STUDY OF MITOCHONDRIA IN RAT LIVER : Dry Mass, Wet Mass, Volume, and Concentration of Solids

The dry mass, wet mass, and volume of mitochondria of normal rat liver were determined, as well as nitrogen content and concentration. A scheme of multiple approaches to these quantities was devised, permitting comparison of values obtained by independent methods. The following basic values are considered highly accurate: Mean dry mass, 13.6 x 10^-14 g; mean wet mass, 51.8 x 10^-14 g; mean volume, 0.43 µ³; nitrogen content, 1.75 x 10^-14 g The work emphasizes the fact that in mitochondria the quantities, mass, and volume occur in logarithmic-normal distributions.     

Native and Modified Subtilisin 72 as a Catalyst for Peptide Synthesis in Media with a Low Water Content

The catalytic efficiencies of native subtilisin, its noncovalent complex with polyacrylic acid, and the subtilisin covalently immobilized in a cryogel of polyvinyl alcohol were studied in the reaction of peptide coupling in mixtures of organic solvents with a low water content in dependence on the medium composition, reaction time, and biocatalyst concentration. It was established that, in media with a DMF content >80%, the synthase activity of modified subtilisins is higher than that of the native subtilisin. The use of N-acylpeptides with a free carboxyl group was found to be possible in organic solvents during the enzymatic synthesis catalyzed by both native and immobilized subtilisin. A series of tetrapeptide p-nitroanilides of the general formula Z-Ala-Ala-Xaa-Yaa-pNA (where Xaa is Leu, Lys, or Glu and Yaa is Phe or Asp) was obtained in the presence of immobilized enzyme in yields of 70–98% in DMF–MeCN without any activation of the carboxyl component and without protection of side ionogenic groups of polyfunctional amino acids.     

Protein Electrophoretic Pattern of Two Chlorella Mutants with Low and High Content of Sulphur-Amino Acids

Two mutants of Chlorella vulgaris characterized by high (HS) or low (LS) content of sulphur-amino acids were compared to the wild strain with respect to their protein electrophoretic pattern. Three new bands, not present in the LS and wild strains, were found in the HS mutant. In algae grown in the presence of ³⁵S labelled sulphate two of these new bands showed a very high ³⁵S specific activity. Some electrophoretic bands common to LS, HS, and wild strain, were present in different proportions and showed different levels of specific radioactivity for each strain. Therefore, mutational events appear to have affected both the amino acid composition of single proteins and the relative amount of proteins with high and low sulphate content.     

Low Temperature-Induced Decrease in trans-Delta-Hexadecenoic Acid Content Is Correlated with Freezing Tolerance in Cereals

The effect of growth at 5°C on the trans-Δ³-hexadecenoic acid content of phosphatidyl(d)glycerol was examined in a total of eight cultivars of rye (Secale cereale L.) and what (Triticum aestivum L.) of varying freezing tolerance. In these monocots, low temperature growth caused decreases in the trans-Δ³-hexadecenoic acid content of between 0 and 74% with concomitant increases in the palmitic acid content of phosphatidyl(d)glycerol. These trends were observed for whole leaf extracts as well as isolated thylakoids. The low growth temperature-induced decrease in the trans-Δ³-hexadecenoic acid content was shown to be a linear function (r² = 0.954) of freezing tolerance in these cultivars. Of the six cold tolerant dicotyledonous species examined, only Brassica and Arabidopsis thaliana L. cv Columbia exhibited a 42% and 65% decrease, respectively, in trans-Δ³-hexadecenoic acid content. Thus, the relationship between the change in trans-Δ³-hexadecenoic acid content of phosphatidyl(d)glycerol and freezing tolerance cannot be considered a general one for all cold tolerant plant species. However, species which exhibited a low growth temperature-induced decrease in trans-Δ³-hexadecenoic acid also exhibited a concomitant shift in the in vitro organization of the light harvesting complex II from a predominantly oligomeric form to the monomeric form. We conclude that the proposed role of phosphatidyl(d)glycerol in modulating the organization of light harvesting complex II as a function of growth temperature manifests itself to varying degrees in different plant species. A possible physiological role for this phenomenon with respect to low temperature acclimation and freezing tolerance in cereals is discussed.     

海南岛两栖动物调查及珍稀和特有种的测量数据

1995年至2005年对海南岛进行了多次两栖动物调查,海南师范大学生物系每年进行本科生动物学野外实习,也采集了大量的两栖动物标本。所有标本均保存在生物系标本室内,经整理编号,统计共有955号,分类鉴定得35种,分别隶属16属7科2目。本文报道整理结果,并将其中海南特有物种及国内分布区狭窄的个别物种的测量数据加以报道,以供参考。