Branched isomeric 1,2,3-triazolium-based ionic liquids: new insight into structure-property relationships.

A series of four isomeric 1,2,3-triazolium-based ionic liquids (ILs) with vary degree of branching were synthesized and characterized to investigate the effect of ion branching on thermal and physical properties of the resulting IL. It was found that increased branching led to a higher ionicity and higher viscosity. The thermal properties were also altered significantly and spectral changes in the near edge X-ray absorption fine structure (NEXAFS) spectra show that branching affects intermolecular interaction. While the ionicity and viscosity varying linearly with branching, the MDSC and NEXAFS measurements show that the cation shape has a stronger influence on the melting temperature and absorptive properties than the number of branched alkyl substituents.

Glucagon-like peptide-1 secretion in people with versus without type 2 diabetes: a systematic review and meta-analysis of cross-sectional studies.

AIMS/HYPOTHESIS: The aim of this systematic review was to synthesise the study findings on whether GLP-1 secretion in response to a meal tolerance test is affected by the presence of type 2 diabetes (T2D). The influence of putative moderators such as age, sex, meal type, meal form, and assay type were also explored. METHODS: A literature search identified 32 relevant studies. The sample mean and SD for fasting GLP-1TOTAL and GLP-1TOTAL iAUC were extracted and used to calculate between-group standardised mean differences (SMD), which were meta-analysed using a random-effects model to derive pooled estimates of Hedges' g and 95 % prediction intervals (PI). RESULTS: Pooled across 18 studies, the overall SMD in GLP-1TOTAL iAUC between individuals with T2D (n = 270, 1047 ± 930 pmol·L-1·min) and individuals without T2D (n = 402, 1204 ± 937 pmol·L-1·min) was very small, not statistically significant and heterogenous across studies (g = -0.15, p = 0.43, PI: -1.53, 1.23). Subgroup analyses demonstrated an effect of assay type whereby Hedges' g for GLP-1 iAUC was greater in individuals with, versus those without T2D when using ELISA or Mesoscale (g = 0.67 [moderate], p = 0.009), but not when using RIA (g = -0.30 [small], p = 0.10). Pooled across 30 studies, the SMD in fasting GLP-1TOTAL between individuals with T2D (n = 580, 16.2 ± 6.9 pmol·L-1) versus individuals without T2D (n = 1363, 12.4 ± 5.7 pmol·L-1) was small and heterogenous between studies (g = 0.24, p = 0.21, PI: -1.55, 2.02). CONCLUSIONS: Differences in fasting GLP-1TOTAL and GLP-1TOTAL iAUC between individuals with, versus those without T2D were generally small and inconsistent between studies. Factors influencing study heterogeneity such as small sample sizes and poor matching of groups may help to explain the wide prediction intervals observed. Considerations to improve comparisons of GLP-1 secretion in T2D and potential mediating factors more important than T2D diagnosis per se are outlined. PROSPERO ID: CRD42020195612.

In vitro activity of nicotinamide adenine dinucleotide- and nicotinamide adenine dinucleotide phosphate-linked 15-hydroxyprostaglandin dehydrogenases in placentas from normotensive and preeclamptic/eclamptic pregnancies.

Concentrations of prostaglandins E2 and I2 may be decreased in preeclamptic and eclamptic pregnancies. Because these prostaglandins produce vasodilation and inhibit platelet aggregation it has been suggested that a reduction in their biosynthesis might play an important role in the pathogenesis of the hypertension and coagulation abnormalities associated with preeclampsia. Placental tissue is an extremely rich source of several enzymes that catalyze the catabolism of prostaglandins. The present study was initiated to determine whether one of these catabolic enzymes might be increased in preeclamptic/eclamptic pregnancies. The activities of the NAD- and the NADP-linked 15-hydroxyprostaglandin dehydrogenases were measured in 16 preeclamptics (mean diastolic pressure, 108 +/- 13 mmHg) and compared with 16 normotensive controls matched for age (20.8 +/- 5.43 vs. 20.6 +/- 5.16) and gestational week of delivery (34.6 +/- 5.40 vs. 35.0 +/- 5.06). These results indicate that the activity of the placental NAD-linked 15-hydroxyprostaglandin dehydrogenase is elevated in preeclampsia (40.1 +/- 31.3 vs. 14.9 +/- 8.30 mU/g tissue, P less than 0.01). If this increase were also expressed in vivo, its effect on prostaglandin metabolism could be mistaken for impaired prostacyclin biosynthesis unless both the 6-keto- and 6,15-diketo-metabolites of prostacyclin were measured.

Humanization of a murine monoclonal antibody by simultaneous optimization of framework and CDR residues.

Optimal protein function often depends on co-operative interactions between amino acid residues distant in the protein primary sequence yet spatially near one another following protein folding. For example, antibody affinity is influenced by interactions of framework residues with complementarity-determining region (CDR) residues. However, despite the abundance of antibody structural information and computational tools the humanization of rodent antibodies for clinical use often results in a significant loss of affinity. To date, antibody engineering efforts have focused either on optimizing CDR residues involved in antigen binding or on optimizing antibody framework residues that serve critical roles in preserving the conformation of CDRs. In the present study a new approach which permits the rapid identification of co-operatively interacting framework and CDR residues was used to simultaneously humanize and optimize a murine antibody directed against CD40. Specifically, a combinatorial library that examined eight potentially important framework positions concomitantly with focused CDR libraries consisting of variants containing random single amino acid mutations in the third CDR of the heavy and light chains was expressed. Multiple anti-CD40 Fab variants containing as few as one murine framework residue and displaying up to approximately 500-fold higher affinity than the initial chimeric Fab were identified. The higher affinity humanized variants demonstrated a co-operative interaction between light chain framework residue Y49 and heavy chain CDR3 residue R/K101 (coupling energy, DeltaGI=0.9 kcal/mol). Screening of combinatorial framework-CDR libraries permits identification of monoclonal antibodies (mAb) with structures optimized for function, including instances in which the antigen induces conformational changes in the mAb. Moreover, the enhanced humanized variants contain fewer murine framework residues and could not be identified by sequential in vitro humanization and affinity muturation strategies. This approach to identifying co-operatively interacting residues is not restricted to antibody-antigen interactions and consequently, may be used broadly to gain insight into protein structure-function relationships, including proteins that serve as catalysts.

Targeted antiangiogenic therapy for cancer using Vitaxin: a humanized monoclonal antibody to the integrin alphavbeta3.

Angiogenesis plays a central role in the growth and metastasis of cancers. Strategies aimed at interfering with tumor blood supply offer promise for new cancer therapies. Vitaxin (an anti-alphavbeta3 antibody) interferes with blood vessel formation by inducing apoptosis in newly generated endothelial cells. This Phase I study evaluates the safety and pharmacokinetics of Vitaxin in humans with cancer. Eligible patients demonstrated progressive tumors with stage IV disease and an Eastern Cooperative Oncology Group performance status < or =2. Treatment consisted of six weekly infusions of Vitaxin. Escalating doses from 0.1 and 4.0 mg/kg/week were evaluated based on the expectation that plasma levels would bracket the effective in vitro concentration. Escalation beyond 4 mg/kg/week was limited by drug availability. Adverse events were assessed weekly. Pharmacokinetics were performed weekly through week 9. Clinical response was assessed at week 9. Of 17 patients treated, 14 were evaluable for response. Treatment was well tolerated with little or no toxicity. The most common side effect was infusion-related fever, which could be controlled with prophylactic antipyretics. Doses > or =1 mg/kg/week produced plasma concentrations sufficient to saturate the alphavbeta3 receptor in vitro (25 microg/ml). Vitaxin demonstrated a half-life in excess of 5 days at higher doses with no accumulation over 6 weeks of therapy. One patient demonstrated a partial response, and seven patients demonstrated stable disease. Three patients received Vitaxin beyond the first cycle of therapy. Each of these patients demonstrated disease stabilization that in one case lasted 22 months. At the doses and schedule studied, Vitaxin appears safe and potentially active, suggesting that vascular integrin alphavbeta3 represents a clinically relevant antiangiogenic target for prolonged cancer therapy.

Interim report of the Presidential Commission on the Human Immunodeficiency Virus Epidemic: Chairman's recommendations--Part I.

PIP: The Presidential Commission was created in September 1987 with the mandate to advise the White House "on the public health dangers including the medical, legal, ethical, social, and economic impact, from the spread of the HIV and resulting illnesses including AIDS, AIDS related complex, and other related conditions." This paper covers the Commission's interim policy recommendations as of March 15, 1988, in the areas of intravenous drug abuse, patient care, and basic research and drug development. The scope of recommendations in the area of intravenous drug abuse includes provision of treatment services, treatment research, drug abuse prevention, and outreach education. There must be a national policy of "treatment on demand" for drug users. An expanded program of drug treatment research must include research on cocaine as well as heroin addiction treatment. Drug abuse prevention should coordinate efforts at all levels of government as well as community and religious organizations and schools. Outreach education, which is especially difficult with drug users because drug use is illegal, will cost roughly $126.5 million a year over current funding. Outreach programs should train and utilize street outreach workers, including former addicts, and should have special focuses on adolescents, minorities, and women of childbearing age. The scope of recommendations in the area of patient care includes health care provider education, health care systems, psychosocial needs, nursing care, minorities and underserved populations, and information coordination and exchange. AIDS needs to be integrated into the educational curricula of medical and all other health professional schools. In the area of health care systems, the recommendations emphasize the need for integrated community-based services for people with HIV infection. 22 AIDS Service Delivery Demonstration projects are currently being conducted in the US, 13 funded by the US Public Health Service and 9 funded by the Robert Wood Johnson Foundation.^ieng

Seroepidemiology of Toxoplasma gondii in dogs in Trinidad and Tobago.

A cross-sectional study was conducted to determine the seroprevalence of Toxoplasma gondii agglutinins and to investigate the relationship between various risk factors and occurrence of toxoplasmosis in dogs in Trinidad. Of a total 250 dogs, comprising domestic, hunting and stray dogs, 80 (32.0%) were positive for T. gondii agglutinins at a titre of > or =1:32 using a latex agglutination test. Stray dogs (60.5%) had statistically significantly higher (P<0.001) seroprevalence for toxoplasmosis than hunting dogs (30.5%) and domestic dogs (25.5%). Amongst dogs whose ages were known, the prevalence of toxoplasmosis was significantly highest (P=0.037) in dogs in the >2-3 years age group compared with other age groups. Dogs that consumed home-cooked foods had a seroprevalence of 32.9% compared with those fed commercial dog foods (17.2%) and dogs fed both home-cooked and commercial foods (21.0%). However, the difference was not statistically significant (P>0.05; chi(2)). The rather high prevalence of toxoplasmosis in stray dogs is a good indication of the extent of the infection in the environment.

Regulation of CTP:phosphocholine cytidylyltransferase activity and subcellular location by phosphorylation in Chinese hamster ovary cells. The effect of phospholipase C treatment.

The phosphorylation state of cytidylyltransferase in Chinese hamster ovary (CHO) cells was correlated with its subcellular distribution and activity in vivo. Western blot analysis of soluble and particulate fractions from control and phospholipase C-treated cells revealed slower migrating forms of cytidylyltransferase present only in the soluble fraction of control cells. These were abolished by incubating the soluble fraction at 37 degrees C in the presence of 5 mM Mg2+ but persisted if 135 mM NaF was present in the incubation. CHO cells were labeled with 32Pi, and cytidylyltransferase was immunoprecipitated from soluble and particulate fractions from control and phospholipase C-treated cells. The slower migrating forms of cytidylyltransferase, present in the soluble fraction of control cells, were phosphorylated at multiple sites. Although an equivalent amount of cytidylyltransferase was immunoprecipitated from the particulate fraction of phospholipase C-treated cells, it contained little 32P. Pretreatment of the CHO cells with okadaic acid, an inhibitor of type 1 and 2A phosphatases, prevented the stimulation of cytidylyltransferase in vivo by phospholipase C. These results demonstrate that dephosphorylation of soluble cytidylyltransferase is required for the phospholipase C-mediated translocation of cytidylyltransferase in CHO cells.

Phosphorylation of CTP:phosphocholine cytidylyltransferase in vivo. Lack of effect of phorbol ester treatment in HeLa cells.

The production and characterization of an antibody to rat liver CTP:phosphocholine cytidylyltransferase is described. This antibody quantitatively precipitated cytidylyltransferase from both rat liver and HeLa cell cytosol. Following affinity purification, the antibody was used to demonstrate, for the first time, the phosphorylation of cytidylyltransferase in vivo. Following the immunoprecipitation of cytidylyltransferase from HeLa cells, acid hydrolysis, and thin layer electrophoresis of the amino acids, only [32P]phosphoserine was detected. The phosphorylation state of cytidylyltransferase in HeLa cells was examined following treatment with phorbol ester for 1 h. In agreement with previous studies, the incorporation of [3H]choline into phosphatidylcholine via the CDP-choline pathway was stimulated 5-fold in cultures of HeLa cells following treatment with phorbol ester for 1 h. However, no appreciable translocation of cytidylyltransferase was detected, despite the utilization of two different methods of cell lysis. Furthermore, the inclusion of phosphatase inhibitors and chelators of divalent cations in the homogenization buffers had no effect on the observed distribution or activity of the enzyme. Immunoprecipitated cytidylyltransferase was phosphorylated to the same extent, and on serine residues only, in both control and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-treated cells. Measurement of the pool sizes of the aqueous intermediates of the CDP-choline pathway, following TPA treatment, revealed a modest decrease in the phosphocholine pool only, consistent with an activation of cytidylyltransferase.

Purification of the human placental NAD-linked 15-hydroxyprostaglandin dehydrogenase.

An NAD-linked 15-hydroxyprostaglandin dehydrogenase has been purified 13,100-fold from human placental tissue. The specific activity of the purified enzyme ranges from 6900 to 8300 mU/mg protein depending on the method used to determine the protein concentration. On discontinuous electrophoresis in sodium dodecyl sulfate more than 95% of the protein migrates as a single band; its estimated molecular weight is 25.5-26.0 kDa. This is half the value obtained when the molecular weight is estimated under non-denaturing conditions and suggests that the enzyme is composed of two identical or nearly identical subunits.

The effect of NaCl intake on 9-ketoprostaglandin reductase activity in the rabbit kidney.

Renal 9-ketoprostaglandin reductase activity from rabbits fed 0.3 g or 2.5 g NaCl per 100 g chow was measured in both centrifuged homogenates and in purified enzyme fractions. There was no salt related increase in 9-ketoprostaglandin reductase activity. PGA1-glutathione, 9, 10-phenanthrenequinone, and 4-nitrobenzaldehyde were better substrates for the purified 9-ketoprostaglandin reductases than was PGE2. Several carbonyl reductases were isolated which used PGA1-glutathione, 9, 10-phenanthrenequinone, and 4-nitrobenzaldehyde, but not PGE2, as substrates. Although PGA1-glutathione was a more faithful indicator of PGE2-related 9-ketoprostaglandin reductase activity than either 9, 10-phenanthrenequione or 4-nitrobenzaldehyde, it did not always provide an accurate estimate of that activity.

Immunolocalization of membrane-associated CTP:phosphocholine cytidylyltransferase in phosphatidylcholine-deficient Chinese hamster ovary cells.

The location of CTP:phosphocholine cytidylyltransferase in Chinese hamster ovary (CHO) cells made deficient in phosphatidylcholine was determined by immunofluorescence techniques. A rabbit polyclonal antibody was raised against a synthetic peptide corresponding to the amino-terminal 17 amino acid residues of rat liver cytidylyltransferase. The antibody recognized both native and denatured cytidylyltransferase from both rat liver and CHO cells. CHO cells were treated with phospholipase C to alter the lipid composition of the plasma membrane and to elicit translocation of cytidylyltransferase from the less active soluble pool to an activated membrane fraction. Visualization of cytidylyltransferase by indirect immunofluorescence revealed staining of the nuclear envelope in phospholipase C-treated cells but not in untreated cells. CHO cells were also starved for choline and supplemented with a choline analogue to provide an alternative technique of rendering the cells phosphatidylcholine-deficient. Although this treatment should affect different cellular membranes than those affected by phospholipase C treatment, cytidylyltransferase still translocated to the nuclear envelope, as shown by indirect immunofluorescence. These results indicate that activated, membrane-bound cytidylyltransferase is associated with the nuclear membrane and suggest that the nuclear membrane may be a site of de novo phosphatidylcholine synthesis.