Effect of isoelectric point on biodistribution and inflammation imaging with indium-111-labelled IgG

Electrostatic effects play an important role in protein interactions and may alter the biodistribution of antibodies. To study the effect of molecular charge on the biodistribution and infection imaging properties of human polyclonal immunoglobulin G (IgG), its iso electric point was varied by changing the level of diethylene triamine penta-acetic acid (DTPA) substitution: 0.8, 0.9, 3.7, 5.1 and 5.9 DTPA/IgG. Biodistributions of the different IgG preparations were determined at 10 min, 1, 6, 24, and 48 h post injection in normal rats, and infection imaging properties were determined in rats withEscherichia coli thigh infections. The biodistribution was significantly affected by pl. The immunoglobulin preparations with 0.9 and 3.7 DTPA/IgG showed faster clearance from the circulation and generally lower accumulation in most organs. The images had a target-to-background ratio of approximately 1.3–2.3:1. These results suggest that even though targeting is not affected by the level of DTPA substitutions, preparations with 0.9 and 3.7 DTPA/IgG may be superior imaging agents because of reduced accumulation by background organs.     

介绍一种不加盖玻片的核酸原位杂交改良法

核酸原位杂交程序中探针和靶基因的加热变性和杂交为整个程序中最重要的环节,目前国内外最常用的方法是在切片上滴加DNA探针溶液后用盖玻片复盖组织,并加胶泥或其他封固剂封闭玻片四周,变性杂交后需拆除盖玻片,这一操作过程易损坏组织切片或出现干片、脱片。作者针对上述情况,对传统的核酸原位杂交方法中的部分程序加以改良,采用不加盖玻片直接在蒸汽中变性方法,经多次实验证明此方法稳定、可靠、简便,结果满意。     

Taurine entry into perilymph of the guinea pig

Taurine is a β-aminosulfonic acid and is a ubiquitous amino acid whose role in the cochlea is not well established. In this study, its entry from blood into perilymph was investigated in the guinea pig as animal model. The penetration rate of [³H]taurine (molecular weight 125) into the perilymph of the scala vestibuli was measured 1 and 2 h after the intravenous infusion of [³H]taurine in nephrectomized animals. Results showed a rate of penetration in perilymph related to plasma at 36 ± 4.7% (n = 5) after 1 h and 43 ± 5.6% (n = 5) after 2 h. Compared to the penetration rate of urea (molecular weight 60) and mannitol (molecular weight 186) reported previously in rats, a passive entry of taurine into perilymph through the blood-perilymph barrier is suggested. Received: 30 July 1997 / Accepted: 15 January 1998     

Randomized clinical trial of ascorbic acid in the treatment of pressure ulcers

The objective of this study was to assess the effects of ascorbic acid supplementation, 500 mg twice daily in the treatment of pressure ulcers as an adjunct to standardized treatment.

The design consisted of a multicenter blinded randomized trial. The control group received 10 mg of ascorbic acid twice daily.

Patients from 11 nursing homes and 1 hospital participated.

Main outcome measures included wound survival, healing rates of wound surfaces, and clinimetric changes over 12 weeks.

Eighty-eight patients were randomized. Intention-to-treat analysis showed that the wound closure probability per unit time (i.e., the closure rate) was not higher in the intervention group than in the control group (Cox hazard ratio of 0.78 [90% precision interval, 0.44–1.39]). Mean absolute healing rates were 0.21 and 0.27 cm²/week in the intervention and control group, respectively (PI of the adjusted difference: −0.17 to 0.13). Relative healing rates and healing velocities did not show favorable results of ascorbic acid supplementation, either. A panel scored slides of the ulcers with a report mark between 1 (bad) and 10 (excellent). The improvement was 0.45 and 0.72 points per week in the intervention and control group, respectively (PI of the adjusted difference: −0.50 to 0.20). With another clinimetric index we could not show any differences, either.

These data do not support the idea that ascorbic acid supplementation (500 vs. 10 mg twice daily) speeds up the healing of pressure ulcers.     

Metabolic myocardial viability assessment with iodine 123-16-iodo-3-methylhexadecanoic acid in recent myocardial infarction: Comparison with thallium-201 and fluorine-18 fluorodeoxyglucose

The best test presently available to ascertain residual viability within an infarct-related area involves the use of fluorine-18 fluorodeoxyglucose (FDG) to detect the persistence of some cellular metabolism. Rest reinjection of thallium-201 is a less accurate alternative but is easy to perform. Iodinated fatty acids, which are used with standard gamma cameras, are proposed as markers of cellular metabolism. This study was performed to assess the value of 16-iodo-3-methyl-hexadecanoic acid (MIHA) as a marker of the residual cellular metabolism by comparison with FDG in patients with a recent myocardial infarction, and to evaluate its contribution compared with the²⁰¹Tl stress-redistribution-reinjection technique. Stress-redistribution-reinjection²⁰¹T1 imaging, rest MIHA imaging and glucoseloaded FDG imaging were performed in 22 patients with recent myocardial infarction. Out of the 628 myocardial segments obtained from the left ventricular analysis, 400 were hypoperfused (relative uptake <0.75 of maximum uptake on stress²⁰¹T1 imaging), 177 of which were severely hypoperfused (relative uptake <0.50). Receiver operating characteristic (ROC) curves for predicting metabolic myocardial viability with FDG were derived from the results in respect of (a)²⁰¹T1 activity during exercise, redistribution and reinjection and (b) MIHA up-take, using the two FDG thresholds most commonly considered to define metabolic viability (0.50 and 0.60). Analysis of the 400 hypoperfused segments demonstrated that²⁰¹T1 reinjection was the most accurate test in predicting the presence of myocardial viability (area under the ROI curves=0.85 and 0.86 at the 0.50 and 0.60 FDG thresholds, respectively;P<0.05 vs other tests). The global predictive values of MIHA and²⁰¹T1 reinjection were, respectively, 0.87 and 0.89 at the 0.50 FDG threshold (NS), and 0.82 and 0.87 at the 0.60 FDG threshold (NS). When only the 177 severely hypoperfused segments were considered,²⁰¹T1 reinjection remained the most accurate test (accuracy 0.84 at the 0.50 FDG threshold and 0.82 at the 0.60 FDG threshold), while the accuracy of MIHA decreased significantly (0.78 at the 0.50 FDG threshold and 0.73 at the 0.60 FDG threshold,P<0.05 vs²⁰¹T1 reinjection). In all circumstances, MIHA was less specific than²⁰¹T1 reinjection for the detection of metabolic viability. In conclusion, in patients with recent myocardial infarction, MIHA accurately detects the persistence of metabolic viability, but is not superior to²⁰¹T1.     

Natural killer cell activity and CSF monoamine metabolites in suicide attempters

The aim of this study was to investigate markers of serotonin and immune function in suicidal patients. Cytotoxic activity of natural killer cells (NK) and CD16 lymphocytes were studied in 28 suicide attempters and 26 healthy controls, and related in patients to 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF). Patients with CSF 5-HIAA below the median had significantly lower NK cell activity than other patients. CD16 cell frequency was significantly lower in patients than in controls, and patients also tended to have lower NK cell cytotoxicity than healthy controls. There were no statistically significant correlations between 4-hydroxy-3methoxyphenyl glycol (HMPG), homovanillic acid (HVA), CSF cortisol and NK cell activity. The results support the hypothesis of compromised immune function in suicidal patients with evidence of disordered serotonin function.     

Aza-peptides. III. Experimental structural analysis of aza-alanme and aza-asparagine-containing peptides

To determine the structural perturbations induced by the CαH→Nα exchange in aza-peptides, we have examined by H NMR and IR spectroscopy various derivatives of the aza-analogues of alanine, aspartic acid and asparagine in different organic solvents with increasing polarity. Their general formulas are: R'-AzXaa-NR²R³, R'-Pro-AzXaa-NR²R³ and R-AzXaa-Pro-NR²R³ (where AzXaa denotes the aza-analogue of the amino acid residue Xaa = Ala, Asp, Asn; R = Boc, Z; R², R³= H, Me, iPr). The aza-analogue of an amino acid residue appears to be a strong p-turn-inducing motif, and the AzAsn carboxamide side-chain is capable of interacting, as a proton donor, with the preceding peptide carbonyl group.