Structure-based design of a phosphotyrosine-masked covalent ligand targeting the E3 ligase SOCS2

The Src homology 2 (SH2) domain recognizes phosphotyrosine (pY) post translational modifications in partner proteins to trigger downstream signaling. Drug discovery efforts targeting the SH2 domains have long been stymied by the poor drug-like properties of phosphate and its mimetics. Here, we use structure-based design to target the SH2 domain of the E3 ligase suppressor of cytokine signaling 2 (SOCS2). Starting from the highly ligand-efficient pY amino acid, a fragment growing approach reveals covalent modification of Cys111 in a co-crystal structure, which we leverage to rationally design a cysteine-directed electrophilic covalent inhibitor MN551. We report the prodrug MN714 containing a pivaloyloxymethyl (POM) protecting group and evidence its cell permeability and capping group unmasking using cellular target engagement and in-cell 19F NMR spectroscopy. Covalent engagement at Cys111 competitively blocks recruitment of cellular SOCS2 protein to its native substrate. The qualified inhibitors of SOCS2 could find attractive applications as chemical probes to understand the biology of SOCS2 and its CRL5 complex, and as E3 ligase handles in proteolysis targeting chimera (PROTACs) to induce targeted protein degradation.

Traceless Thioacid-Mediated Radical Cyclization of 1,6-Dienes

Five-membered ring systems are ubiquitous throughout natural products and synthetic therapeutics, and thus, efficient methods to access this essential scaffold are required. Herein, we report the thioacid-mediated, 5-exo-trig cyclization of various 1,6-dienes, with high yields of up to 98%. The labile thioester functionality can be exploited to generate a free thiol residue which can be used as a functional handle or removed entirely to provide the traceless cyclized product.

Glycosylated quantum dots as fluorometric nanoprobes for trehalase

Trehalase is an important enzyme in the metabolic cascades of many organisms, catalysing the hydrolysis of the disaccharide trehalose. Herein we describe the first examples of fluorometric nanoprobes for detection of trehalase, based on trehalose-functionalised quantum dots (QDs). QDs cross-linked with trehalose form aggregates, which are released upon enzymatic cleavage of the trehalose glycosidic bond proportionally to the enzyme concentration, offering a unique and efficient approach for specific sensing of this biologically important enzyme.

Real-Time Multi-Photon Tracking and Bioimaging of Glycosylated Theranostic Prodrugs upon Specific Enzyme Triggered Release

Real-time tracking of prodrug uptake, delivery and activation in vivo represents a major challenge for prodrug development. Herein, we demonstrate the use of novel glycosylated theranostics of the cancer pharmacophore Amonafide in highly-selective, enzymatic triggered release. We show that the use of endogenous enzymes for activated release of the therapeutic component can be observed, in real time, and monitored using one and two-photon bioimaging, offering unique insight into the prodrug pharmacokinetic profile. Furthermore, we demonstrate that the potent cytotoxicity of Amonafide is preserved using this targeted approach.

Mycobacterial para-Hydroxybenzoic Acid-Derivatives (pHBADs) and Related Structures Induce Macrophage Innate Memory

Macrophages are key immune cells for combatting Mycobacterium tuberculosis. However, M. tuberculosis possesses means to evade macrophage bactericidal responses by, for instance, secretion of the immunomodulatory para-hydroxybenzoic acid derivatives (pHBADs). While these molecules have been implicated in inhibiting macrophage responses in an acute context, little is known about their ability to reprogram macrophages via induction of long-term innate memory. Since innate memory has been highlighted as a promising strategy to augment bactericidal immune responses against M. tuberculosis, investigating corresponding immune evasion mechanisms is highly relevant. Our results reveal for the first time that pHBAD I and related molecules (unmethylated pHBAD I and the hexose l-rhamnose) reduce macrophage bactericidal mechanisms in both the short- and the long-term. Moreover, we demonstrate how methyl-p-anisate hinders bactericidal responses soon after exposure yet results in enhanced pro-inflammatory responses in the long-term. This work highlights new roles for these compounds in M. tuberculosis pathogenesis.

Thiyl Radicals: Versatile Reactive Intermediates for Cyclization of Unsaturated Substrates

Sulfur centered radicals are widely employed in chemical synthesis, in particular for alkene and alkyne hydrothiolation towards thioether bioconjugates. The steadfast radical chain process that enables efficient hydrothiolation has been explored in the context of cascade reactions to furnish complex molecular architectures. The use of thiyl radicals offers a much cheaper and less toxic alternative to the archetypal organotin-based radical methods. This review outlines the development of thiyl radicals as reactive intermediates for initiating carbocyclization cascades. Key developments in cascade cyclization methodology are presented and applications for natural product synthesis are discussed. The review provides a chronological account of the field, beginning in the early seventies up to very recent examples; a span of almost 50 years.

Mechanical treatment of plantar fasciitis. A prospective study

A randomized, prospective study was conducted to compare the effectiveness of three individual mechanical modalities in the treatment of plantar fasciitis. Two hundred fifty-five subjects were randomly assigned to one of three treatment groups: custom-made orthoses, over-the-counter arch supports, or tension night splints. Subjects were treated for 3 months, with follow-up visits at 2, 6, and 12 weeks. No statistically significant difference was noted among treatment groups with respect to final outcomes based on first-step pain or pain felt during the day. However, there was a statistically significant difference among the three groups with respect to early patient withdrawal from the study due to continued severe pain, noncompliance, or inability to tolerate the device. Patient compliance was greatest with the use of custom-made orthoses.

Clinical evaluation comparing AxSYM CA 15-3, IMx CA 15-3 and Truquant BRTM RIA

A retrospective clinical study was conducted to compare results obtained by AxSYM(R) CA 15-3(TM), IMx(R) CA 15-3 and Truquant(R) BRTM RIA using surplus serum specimens from healthy volunteers and patients with benign and malignant diseases. Linear regression analysis of AxSYM and IMx CA 15-3 versus Truquant BR RIA for specimens with results 0-250 U/ml gave correlation coefficients of 0. 888 and 0.910 and slopes of 0.67 and 0.69, respectively. For specimens with results 0-2,000 U/ml, slopes were 0.95 and 0.91, respectively. Receiver operator characteristic analyses, based on results from healthy females plus nonmalignant disease patients versus breast cancer patients, for all three assays gave essentially equivalent areas under the curves. Concordance between AxSYM or IMx CA 15-3 and Truquant BR RIA was greater than 92%. Serial dilution of seven serum specimens yielded linear regression correlation coefficients ranging from 0.997 to 1.000 for AxSYM and IMx CA 15-3, and from 0.962 to 0.998 for Truquant BR RIA. The average percent CVs of the calculated assay values for the 7 specimens were 4.9, 2.7 and 18.1 for AxSYM CA 15-3, IMx CA 15-3 and Truquant BR RIA, respectively. Average percent recoveries ranged from 96.2 to 110.7 for AxSYM and IMx CA 15-3, and 81.8 to 93.3 for Truquant BR RIA. Although assay values differ between the two methodologies, AxSYM CA 15-3, IMx CA 15-3 and Truquant BR RIA showed comparable trending results for the 24 breast cancer patients evaluated for serial monitoring.

Acetylcholine-induced and nitric oxide-mediated vasodilation in burns

Microvascular endothelial cells actively participate in local regulation of blood flow and blood-tissue exchange by producing various vasoactive substances including nitric oxide (NO). This study examined microcirculatory changes in the early stage of thermal injury and the NO-related mechanisms. Resistance arterioles of rat cremaster muscle were observed using intravital microscopy. Arteriolar diameter and flow velocity were measured and flow rate was calculated after administration of various vasoactive agonists in burns. In fluid-resuscitated rats with stable systemic blood pressure, microvascular caliber and blood flow were not significantly altered in the first hour following a 25% total body surface area full-thickness scald burn. Topical application of acetylcholine (ACh), an endothelium-dependent vasodilator, increased arteriolar diameter and flow rate in a dose-dependent fashion. The dose-responsive effects of ACh were significantly greater in burned rats than in sham-burned rats, and the augmentation was blocked by inhibition of NO production with NG-monomethyl-l-arginine (L-NMMA). Topical application of adenosine, an endothelium-independent vasodilator, and sodium nitroprusside, an exogenous NO donor, markedly increased arteriolar diameter and flow rate. The effects were not significantly different in burned and sham-burned animals, and the adenosine-induced vasodilation was not blocked by L-NMMA. These data suggest that endothelium-dependent and NO-mediated arteriolar dilation is enhanced in the early stage of thermal injury. This effect may play an important role in the pathophysiological events of microcirculation and blood-tissue exchange in burns.

Conservative treatment of plantar fasciitis. A prospective study

A randomized, prospective study was conducted to compare the individual effectiveness of three types of conservative therapy in the treatment of plantar fasciitis. One hundred three subjects were randomly assigned to one of three treatment categories: anti-inflammatory, accommodative, or mechanical. Subjects were treated for 3 months, with follow-up visits at 2, 4, 6, and 12 weeks. For the 85 patients who completed the study, a statistically significant difference was noted between groups, with mechanical treatment with taping and orthoses proving to be more effective than either anti-inflammatory or accommodative modalities.

Inhibition of natural killer cells by a cytomegalovirus MHC class I homologue in vivo

Herpesviruses, such as murine and human cytomegalovirus (MCMV and HCMV), can establish a persistent infection within the host and have diverse mechanisms as protection from host immune defences. Several herpesvirus genes that are homologous to host immune modulators have been identified, and are implicated in viral evasion of the host immune response. The discovery of a viral major histocompatibility complex (MHC) class I homologue, encoded by HCMV, led to speculation that it might function as an immune modulator and disrupt presentation of peptides by MHC class I to cytotoxic T cells. However, there is no evidence concerning the biological significance of this gene during viral infection. Recent analysis of the MCMV genome has also demonstrated the presence of a MHC class I homologue. Here we show that a recombinant MCMV, in which the gene encoding the class I homologue has been disrupted, has severely restricted replication during the acute stage of infection compared with wild-type MCMV. We demonstrate by in vivo depletion studies that natural killer (NK) cells are responsible for the attenuated phenotype of the mutant. Thus the viral MHC class I homologue contributes to immune evasion through interference with NK cell-mediated clearance.

Identification and characterization of a G protein-coupled receptor homolog encoded by murine cytomegalovirus

This report describes the identification of a murine cytomegalovirus (MCMV) G protein-coupled receptor (GCR) homolog. This open reading frame (M33) is most closely related to, and collinear with, human cytomegalovirus UL33, and homologs are also present in human herpesvirus 6 and 7 (U12 for both viruses). Conserved counterparts in the sequenced alpha- or gammaherpesviruses have not been identified to date, suggesting that these genes encode proteins which are important for the biological characteristics of betaherpesviruses. We have detected transcripts for both UL33 and M33 as early as 3 or 4 h postinfection, and these reappear at late times. In addition, we have identified N-terminal splicing for both the UL33 and M33 RNA transcripts. For both open reading frames, splicing results in the introduction of amino acids which are highly conserved among known GCRs. To characterise the function of the M33 in the natural host, two independent MCMV recombinant viruses were prepared, each of which possesses an M33 open reading frame which has been disrupted with the beta-galactosidase gene. While the recombinant M33 null viruses showed no phenotypic differences in replication from wild-type MCMV in primary mouse embryo fibroblasts in vitro, they showed severely restricted growth in the salivary glands of infected mice. These data suggest that M33 plays an important role in vivo, in particular in the dissemination to or replication in the salivary gland, and provide the first evidence for the function of a viral GCR homolog in vivo.

Reinventing government for the clinical lab

Learn how the power of teamwork fueled by a common goal enabled members of a California government agency to educate thousands of diverse clinical laboratory scientists--despite unanticipated dilemmas and limited resources.

Studies on the structure of complement C3 and the stability of C3 derived phagocytic ligands C3b/iC3b in SJL/J and BALB/c mice

Female SJL/J mice are more susceptible to development of experimental autoimmune myositis than most other mouse strains. Since complement has been implicated in the pathogenesis of inflammatory muscle disease in humans, quantitative and qualitative studies of complement C3 were undertaken in SJL/J and BALB/c mice to determine whether complement may influence disease susceptibility in SJL/J mice. In accordance with previous studies, mature male and female BALB/c mice were shown to have similar serum C3 concentrations. However, differences were found between mature male and female SJL/J mice. Male SJL/J mice have significantly higher serum C3 concentrations than SJL/J females and both sexes of BALB/c mice suggesting that serum C3 concentration may be variably influenced by sex in some mouse strains. Qualitatively, SJL/J mice were shown to have a different allotypic form of C3 (C3F) compared to the common electrophoretically slow form (C3S) found in BALB/c mice and most other mouse strains. Furthermore, studies on the decay rate of C3 revealed that C3b/iC3b fragments are converted to C3c/d at a faster rate in sera from female SJL/J mice compared to female BALB/c mice. Because removal and solubility of immune complexes is influenced by complement C3, it is possible that the more rapid decay of the phagocytic ligands C3b/iC3b may account for the increased susceptibility to development of autoimmune disease in female SJL/J mice.

Antisperm antibody binding to human acrosin: a study of patients with unexplained infertility

OBJECTIVE

Antisperm antibody binding to acrosin was investigated by Western Blotting. The clinical significance of this binding specificity was assessed in a 2-year clinical follow-up.

DESIGN

Consecutive serum samples positive for antisperm antibodies by both enzyme-linked immunosorbent assay and immunobead testing were evaluated for acrosin-binding specificity.

SETTING

The patients were followed in an outpatient setting by private infertility specialists.

PATIENTS

Sixty-five consecutive infertile referral patients with positive antisperm antibody were evaluated. Clinical follow-up was obtained on 8 of 9 females with evidence of antibody binding to acrosin and 19 of 26 females with no specific binding to acrosin.

INTERVENTIONS

Prednisone therapy was given during six courses of intrauterine insemination with husband's sperm. All treatment decisions were made by private physicians independent of the acrosin-binding result.

MAIN OUTCOME MEASURES

Pregnancy status was obtained as part of a 2-year follow-up.

RESULTS

Acrosin-binding specificity was demonstrated in 10 (15%) of the 65 patients. Two of the 8 women (25%) with antibody binding to acrosin and 6 of the 19 women (32%) with antisperm antibodies but no specific binding to acrosin delivered normal children.

CONCLUSIONS

Although antibody-binding specificity to acrosin could be demonstrated, a 2-year clinical follow-up showed no difference in pregnancy rates when compared with women with antisperm antibodies showing no binding specificity to acrosin.

Murine candidiasis: sex differences in the severity of tissue lesions are not associated with levels of serum C3 and C5

Mice deficient in the fifth component of complement are known to be extremely susceptible to lethal challenge with Candida albicans. However, male mice, that have significantly higher concentrations of serum C5 than females, were markedly more susceptible to infection. This difference was observed in both susceptible (CBA/H) and resistant (BALB/c) mice. Levels of serum C3 likewise showed no correlation with susceptibility.

An enzyme immunoassay for carcinoembryonic antigen which employs simultaneous incubation of specimen with solid phase and enzyme-conjugated antibodies

The Abbott CEA-EIA Monoclonal One-Step procedure was evaluated and compared to the Abbott CEA-EIA Monoclonal, a two-step assay. The reproducibility, sensitivity, recovery and dilution linearity were similar for both assays. Excellent correlations were found between the carcinoembryonic antigen (CEA) values obtained with these assays for healthy donors (n = 261, r = 0.951), patients with benign diseases (n = 171, r = 0.994) and cancer patients (n = 585, r = 0.997). In serial monitoring studies, one-step CEA values paralleled the CEA values determined with the two-step assay regardless of the type of cancer. The advantages of the one-step CEA assay over the two-step assay include significant reduction in both attended and total assay times, reduced sample volume, dry antibody-coated beads, color-coded reagents and an extended range for the standard curve. These test improvements were achieved without affecting the reproducibility, sensitivity and accuracy of the CEA measurement.

Comparison of a direct and indirect ELISA for quantitating antisperm antibody in semen

A direct and an indirect quantitative ELISA for antisperm antibody were compared using the spermatozoa and cell-free seminal fluid of 66 infertile males. The normal concentration of sperm binding immunoglobulin was less than or equal to 1.5 fg Ig per spermatozoon for the indirect seminal plasma assay and less than or equal to 1.5 fg Ig per spermatozoon by the direct assay. Of the 66 infertile males, 21% (14/66) had elevated levels of antisperm antibody in their seminal plasma and 26% (17/66) had elevated levels bound directly to their spermatozoa. The direct correlation between the results of these assays was 94%. A simple linear regression analysis between the indirect and direct measurements of antisperm antibody resulted in a correlation coefficient of r = 0.907. There was no statistically significant difference between results from the direct and indirect methods of the patients as a group. However, there was evidence of autospecificity in a small percentage of males who had elevated levels of antisperm antibody by the direct assay that was not detected by the indirect assay using pooled donor spermatozoa.

Platelet antibody binding in systemic lupus erythematosus

Using a combination of enzyme-linked immunosorbent assay and SDS-PAGE with protein blot (Western blotting), increased levels of serum platelet bindable immunoglobulin (SPBIg) were demonstrated in 10 of 10 thrombocytopenic patients with systemic lupus erythematosus (SLE) (7.0-60 fg Ig/platelet) with consistent binding to SDS-PAGE platelet fractions of approximate molecular weight (120 and 80 kDa). This pattern of Ig binding was characteristic of SLE and was not seen in 20 normal volunteers and infrequently seen in 20 patients with idiopathic thrombocytopenic purpura.

Antibody binding specificity to donor sperm in sera from infertile patients

Indirect testing for elevated sera levels of antisperm antibody assumes that all relevant antigens are present on the target sperm utilized. In the present study, the heterogeneity of reactivity of positive sera with sperm from different donors was addressed. When 68 sera that previously tested positive by either sperm immobilization test (SIT) or ELISA or both were tested for antisperm antibody levels by a quantitative ELISA using nine different sperm donors, the frequency of positive reactions was 51% for men and 81% for women. A 50% correlation of SIT- and ELISA-positive results could be improved to 85% using the same sperm specimen. This would improve the overall correlation of functional and ELISA test results from 95% to 99% in the infertile population studied. The data suggest that individual sperm may vary in their antigenic expression and that comparison of methods between laboratories could be improved if equivalent target sperm were used.

A comparison of sperm agglutination and immobilization assays with a quantitative ELISA for anti-sperm antibody in serum

An enzyme-linked immunosorbent assay (ELISA) that quantitates antisperm antibody in serum was compared with standard sperm agglutination and immobilization assays with the use of sera from 40 normal and 292 subfertile individuals. Quantitation of the assay was accomplished by standardizing assay parameters, including the incorporation of a standard reference curve, the number of whole target sperm, the optimal dilution of serum, the selection of microtiter plate, and the time and temperatures involved in the adsorption and incubation phases. With this method, the level of antisperm antibody binding to target sperm in 40 normal fertile individuals was found to be 2.3 (+/- 1.1 standard deviation [SD]) fg immunoglobulin (Ig)/sperm. An increased mean level of 7.4 +/- 3.7 fg Ig/sperm was determined in 84 infertile patients with positive agglutination and/or immobilization tests. In 208 individuals with negative agglutination and immobilization tests the mean concentration of antisperm antibody was 2.5 +/- 1.3 fg Ig/sperm. Postvasectomy patients assayed by this method had a mean Ig binding value of 7.1 +/- 2.4 fg Ig/sperm. The infertile group with positive agglutination and/or immobilization tests had a significantly higher mean antisperm antibody level than the normal fertile group, according to the Student's t-test for independent samples (P less than 0.001). This indirect serum-based assay reproducibly quantitates antisperm antibody binding to whole target sperm, suggests the normal and abnormal levels of antisperm antibody, and correlates with standard functional assays.

Antigenic determinants in idiopathic thrombocytopenic purpura

Serum platelet bindable immunoglobulin (SPBIg) was determined in a group of 23 idiopathic thrombocytopenic purpura (ITP) patients and compared to 20 normal, healthy controls. The mean SPBIg of the ITP group was 16.1 (+/- 17.9 SD) fg/platelet, while the normals were substantially lower, 4.0 (+/- 1.2) fg/platelet. Sera from patients of both groups were then incubated with platelet fractions immobilized on nitrocellulose membrane strips (Western Blotting) to detect platelet antigen specificity using a peroxidase labelled indicator antibody. The normal patient sera did not react with platelet fractions on the nitrocellulose strips. However, 21 of 23 ITP sera bound to one or more platelet fractions with large variations in the number and molecular weights of the platelet fractions identified by ITP antibody. These observations suggest the presence of multiple antigenic binding sites for platelet specific immunoglobulin in ITP sera. This variation may reflect heterogeneous antibodies binding to diverse antigens or homogeneous antibodies to a limited number of antigenic determinants shared by several discrete platelet molecules.

Quantitation of sperm bindable IgA and IgG in seminal fluid

Seminal fluid and serum from 95 infertile males were assayed for sperm bindable immunoglobulins using an indirect ELISA with whole target sperm. The ELISA method was compared to seminal fluid and serum immobilization and agglutination assays (functional assays). In this infertile group, the ELISA assay was positive in 22% of seminal fluids (greater than 1.2 fg IgA/sperm and greater than 0.3 fg IgG/sperm). The seminal fluid antibodies were IgA and had an accompanying elevated IgG component in 78% of patients. There was a 96% correlation between negative seminal fluid functional assays and negative ELISA, and a 95% correlation between positive seminal fluid functional assays and positive ELISA. Positive serum sperm antibody tests were found in 71% of the infertile males with positive seminal fluid sperm antibodies, but 29% of the infertile males with strongly positive IgA seminal fluid sperm antibodies showed normal levels of serum sperm antibodies by either ELISA or functional assays. The ELISA method gives reproducible quantitation of sperm antibodies in seminal fluid and correlates well with accepted functional assays. Comparisons with serum sperm antibody assays suggests that seminal fluid sperm antibody analysis complements the serum analysis of sperm antibodies.

Heparin-associated thrombocytopenia: antibody binding specificity to platelet antigens

Sera from four patients with heparin-associated thrombocytopenia (HAT) were evaluated by a quantitative enzyme-linked immunosorbent assay (ELISA) to detect heparin-dependent serum platelet-bindable immunoglobulin (S-PBIg) and by Western blotting and immunoprecipitation to investigate the specificity of the antibody binding. All HAT sera showed mildly increased S-PBIg (mean, 7.8 fg per platelet; normal, less than 6.0 fg per platelet) to intact target platelets in the ELISA, which was markedly increased in the presence of heparin (mean, 20.9 fg per platelet). This increase was 20-fold greater than normal control sera, which showed a mean differential increase of only 0.5 fg per platelet. Immunoglobulin binding specificity to platelet antigens was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis of platelet lysate with transfer of the platelet fractions onto nitrocellulose strips (Western blotting) and subsequent immunoassay using HAT and normal sera. In the presence of heparin, the four HAT patients demonstrated increased binding of immunoglobulin to platelet antigens of apparent molecular weights of 180, 124, and 82 kd. Radiolabeled heparin when incubated with HAT sera, normal sera, or albumin blanks bound to platelet proteins of the same apparent molecular weights. These observations are consistent with current hypotheses suggesting that HAT antibody is directed to heparin-platelet complexes or, alternatively, that heparin induces conformational change of antigenic sites on the platelet membrane.

An enzyme-linked immunosorbent assay for the evaluation of thrombocytopenia induced by heparin

Five patients with heparin-associated thrombocytopenia (HAT) were evaluated by platelet aggregation and quantitation of immunoglobulin binding to intact target platelets in both the presence and absence of heparin. These patients developed thrombocytopenia (12,000 to 70,000 platelets/microliter) 7 to 15 days and embolic and hemorrhagic complications 9 to 15 days after the initiation of heparin therapy. Platelet aggregation after the addition of heparin was demonstrated in two of four HAT serum samples, whereas normal serum samples showed no significant platelet aggregation. The five HAT serum samples showed normal to elevated baseline serum platelet-bindable immunoglobulin (SPBIg) with a range of 4.3 to 11.4 fg/platelet (normal less than or equal to 1.0 to 6.5 fg/platelet). When HAT sera were incubated with target platelets and heparin (5 U/ml), the SPBIg increased to 8.5 to 37.5 fg/platelet, a mean increase of 148% in the presence of heparin. Normal and control serum samples (from 10 normal laboratory volunteers, nine patients without thrombocytopenia receiving heparin, nine patients with autoimmune thrombocytopenic purpura, and nine patients with nonimmune thrombocytopenia not receiving heparin) showed only a slight increase in SPBIg of 0 to 2.8 fg/platelet above baseline, a mean increase of 15% after heparin incubation with the serum samples. The measurement of SPBIg of washed platelets incubated with test serum samples in the presence and absence of heparin is potentially a specific and sensitive in vitro test for the diagnosis of HAT and may prove more sensitive than platelet aggregation studies with heparin.

Pipothiazine palmitate in the management of aggressive mentally handicapped patients

The efficacy of intramuscular pipothiazine palmitate (PP) in the management of aggressive mentally handicapped patients was examined in a double-blind, placebo-controlled, cross-over study, in which 30 patients received each treatment for 13 weeks. A target symptom scale of aggressiveness (TSA) and a clinical global impression scale of efficacy were rated at monthly intervals, and an extra-pyramidal side-effects scale weekly. The patients showed marked improvement during treatment with PP, which was assessed as superior to placebo. Individual and total TSA scores were also reduced compared to placebo.

A quantitative ELISA procedure for the measurement of membrane-bound platelet-associated IgG (PAIgG)

A quantitative ELISA assay for the measurement of in vivo bound platelet-associated IgG (PAIgG) using intact patient platelets is presented. The assay requires quantitation and standardization of the number of platelets bound to microtiter plate wells and an absorbance curve using quantitated IgG standards. Platelet-bound IgG was measured using an F(ab')2 peroxidase labeled anti-human IgG and o-phenylenediamine dihydrochloride (OPD) as the substrate. Using this assay, PAIgG for normal individuals was 2.8 +/- 1.6 fg/platelet (mean +/- 1 SD; n = 30). Increased levels were found in 28 of 30 patients with clinical autoimmune thrombocytopenia (ATP) with a range of 7.0-80 fg/platelet. Normal PAIgG levels were found in 26 of 30 patients with nonimmune thrombocytopenia. In the sample population studied, the PAIgG assay showed a sensitivity of 93%, specificity of 90%, a positive predictive value of 0.90, and a negative predictive value of 0.93. The procedure is highly reproducible (CV = 6.8%) and useful in evaluating patients with suspected immune mediated thrombocytopenia.

Preoperative AT-III values and clinical postoperative thrombosis: a comparison of three antithrombin-III assays

Three antithrombin-III assays (Sigma functional plasma, von Kaulla functional serum, and Calbiochem-Behring radial immunodiffusion) are compared using preoperative serum and plasma from 48 patients admitted for cardiovascular or other major vascular surgery. Medical records were reviewed for evidence of thrombotic complications. Eight patients (17%) in this selected population had clinical evidence of postoperative thrombotic complications. The sensitivity and specificity for each AT-III assay were calculated, and the positive and negative predictive values in this population were determined. Sigma's plasma AT-III had the highest positive predictive value (67%) and negative predictive value (100%). The functional serum and RID assays had significantly lower positive predictive values (23% and 38% respectively) and negative predictive values of 86%. Using the Two Sample t-Test to evaluate differences in AT-III values between the two patient groups, i.e., those who experienced thrombotic complications and those who did not, only the functional plasma AT-III method was statistically significant at a 95% confidence interval.

An enzyme-linked immunosorbent assay for the quantification of serum platelet-bindable IgG

An enzyme-linked immunosorbent assay (ELISA) using F(ab')2 peroxidase-labeled antihuman immunoglobulin and o-phenylenediamine dihydrochloride (OPD) as a substrate was developed to measure serum platelet bindable IgG (S-PBIgG). The assay was made quantitative by standardizing the number of normal "target" platelets bound to microtiter plate wells, and by incorporating quantitated IgG standards with each microtiter plate tested to prepare a standard calibration curve. By this method, S-PBIgG for normal individuals was 3.4 +/- 1.6 fg per platelet (mean +/- 1 SD; n = 40). Increased S-PBIgG levels were detected in 36 of 40 patients with clinical autoimmune thrombocytopenia (ATP), ranging from 7.0 to 85 fg per platelet. Normal S-PBIgG levels were found in 34 of 40 patients with nonimmune thrombocytopenia. This method showed a sensitivity of 90 percent, specificity of 85 percent, and in the sample population studied, a positive predictive value of 0.86 and a negative predictive value of 0.90. This assay is highly reproducible (coefficient of variation was 6.8%) and appears useful in the evaluation of patients with suspected immune-mediated thrombocytopenia.

Comparative study of clearance of 10% and 20% fat emulsion

The rate of fat emulsion clearance from the blood of 10 healthy adult male volunteers administered 0.1 gram of fat per kilogram body weight as 10% or 20% safflower oil emulsion (Liposyn) was studied. The subjects were hospitalized for 2 days and each was given the predetermined amount of one of the two fat emulsions (10% or 20%) by rapid injection into a peripheral vein and the rate of clearance of the emulsion determined over a 60-minute period, beginning when half of the emulsion had been injected. There was no significant difference in the clearance rate between the two emulsions. It is concluded that 20% fat emulsion is a safe as 10% fat emulsion for use in intravenous nutritional support.

Quantitative structure-activity relationships for biguanides, carbamimidates, and bisbiguanides as inhibitors of Streptococcus mutans No. 6715

Thirty-seven compounds, including 17 biguanides, 6 carbamimidates, and 14 bisbiguanides, were evaluated for potential antiplaque activity by measuring their minimum inhibitory concentrations [MIC (M)] against Streptococcus mutans no. 6715. Linear regression analysis was conducted with the log 1/MIC (M) values and log P, pi, sigma, and MR. The best correlation for the biguanides (r2 = 0.92) was obtained with log P and (log P)2. When the biguanides were included with the carbamimidates, essentially the same correlation (r2 = 0.91) was obtained with log P and (log P)2. The best correlation for the bisbiguanides (r2 = 0.70) was also obtained with log P and (log P)2. Use of an indicator variable (I) for the bisgiguanides allowed all three groups to be included in one equation, which accounted for over 87% of the variance in the data for inhibition of bacterial growth. These results from the classical parabolic model were also compared with those from the recently developed bilinear model.

Synthesis and in vivo antimalarial evaluation of isopropyl [(4-chlorophenyl)amino]iminomethylcarbamimidate

Isopropyl [(4-chlorophenyl)amino]iminomethylcarbamimidate was synthesized as a potential antimalarial agent. Biological activity was evaluated against Plasmodium lophurae in turkeys. The activity of this compound was compared to its nitrogen isostere, chloroguanide.

Synthesis, physicochemical parameters, and in vitro evaluation of N1-p-chlorophenyl-N5-alkylbiguanides

A series of N1-p-chlorophenyl-N5-alkylbiguanides were synthesized as potential inhibitors of dental plaque. Partition coefficients and pKa values were determined by standard methods. Biological activity was evaluated against Streptococcus mutans, a pure strain of plaque-forming bacteria. All compounds were compared to chlorhexidine acetate.

Survival of functional pancreatic acinar tissue in circumfusion organ culture enhanced by chemically defined medium with hydrocortisone

Pancreatic explants from perinatal or 1-week-old rat circumfusion organ cultured with an insulin-free variant of Trowell's Medium T8 survive functionally, as judged from tissue amylase content, for about 3 days. When hydrocortisone 21-sodium succinate, 1.0 mg/liter, is added to the chemically defined medium, high levels of anylase persist for longer periods. Explants from 7-day-old animals, circumfusion cultured with hydrocortisone-supplemented medium, maintain tissue amylase levels equal to or greater than those of uncultured control pancreas for at least 5 days of culture, and over this period they release amylase into culture medium at a stable rate. Methods for maintaining functional pancreatic acinar tissue in culture provide a new biological model for in vitro analysis of the early defects of potential chemical carcinogens on this target organ.

Trichuris trichiura infestations in the United Kingdom and treatment with difetarsone

Stool specimens were examined for the parasite Trichuris trichiura from 1,860 patients in 17 hospitals for the mentally subnormal in the U.K. It was found in 10 of these hospitals, and an overall incidence of 13.2% was recorded. Most cases occurred in the South, where the overall incidence was 36.3%.Difetarsone was used in the treatment of infestations in two hospitals, and proved to be very well tolerated, cure rates of 81 to 88% being obtained.