Re: Delayed interval delivery and multiple pregnancy--use of cervical suture.
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Abortion, Spontaneous↗
Biomedical subjects
R Sweet
Publications and source records attributed to R Sweet.
Objective identification of dizzy patients by vestibulo-ocular and vestibulospinal testing.
OBJECTIVE: To evaluate how well two new objective tests of vestibular function might help identify truly dizzy patients. DESIGN: A prospective study of dizzy patients. SETTING: Department of Otolaryngology, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec. METHODS: Vestibular function (in 39 dizziness clinic patients and 30 normals) was characterized as follows: 1. While subjects sat on a rotatable chair trying to look at a wall target, vestibulo-ocular function was quantified by accuracy of ocular stabilization during brief chair turns imposed during 1-second periods of darkness. 2. While subjects stood feet together rotating their head and torso together from the knees, vestibulospinal function was quantified by the fastest comfortable torsal-head movement made without exacerbating dizziness. RESULTS: After plotting ocular stabilization accuracy against fastest comfortable torsal-head velocity, patients and normals tended to separate into two groups. Statistical analysis permitted most dizzy patients (sensitivity: 87%), and most normals (specificity: 83%) to be identified. CONCLUSION: Results are promising, since approximately 40% of patients had no abnormal vestibular signs.
Adolescent↗
Identification of residues in the V domain of CD80 (B7-1) implicated in functional interactions with CD28 and CTLA4.
The CD80 (B7-1) molecule is a 45-60-kD member of the immunoglobulin superfamily that is expressed on a variety of cell types of haematopoietic origin. CD80 can provide a critical costimulatory signal to T cells by interacting with the T cell surface molecule CD28. CD80 also binds to the CD28-related molecule CTLA4, which is expressed on activated T cells, Recently, additional ligands of CD28 and CTLA4 have been described in mice and humans. One of them, CD86 (B-70 or B7-2) was characterized at the molecular level. Although similar in predicted structure to CD80, it is distantly related in amino acid sequence. In this study, human CD80 mutants were generated and tested for their ability to maintain the interaction with CD28 leading to adhesion and enhanced IL-2 production. Two hydrophobic residues in the V-like domain of CD80 were identified as critical for binding to CD28 and are also important for the interaction with CTLA4. These residues are adjacent to the epitope of the BB1 antibody, which inhibits CD28-CD80 interactions. One of these residues, Y87, is conserved in all CD80 and CD86 cloned from various species. These results being to unravel the structural requirements for binding to CD28 and CTLA4.
Abatacept↗
In vitro antibody maturation. Improvement of a high affinity, neutralizing antibody against IL-1 beta.
Abs as therapeutic antagonists should be of relatively high affinity to effectively neutralize their target Ag. Typically, Abs with nanomolar affinities to protein Ags can be obtained in vivo, however, this may not be the upper limit of affinity because the biologic process attempts to optimize Ab function, of which affinity is only one component. SK48, a high affinity neutralizing murine Fab against human IL-1 beta was used to explore the nature of Ab-Ag interactions and the potential for further affinity improvement in vitro using mutagenesis and selection via phage display. The codons of six amino acids in the third complementarity-determining region of the heavy chain (CDR3-H) were both individually and combinatorialy randomized and the resultant libraries were screened for IL-1 binding phenotype. Mutations that reduced affinity suggested that both the backbone conformation of the CDR3 loop and certain side chains are essential for binding, yet alterations to the canonical salt bridge residues at the base of the loop had minimal effect on affinity. Four rounds of selection of the phage Ab libraries on immobilized IL-1 beta gave predominantly the wild-type sequence, indicating efficient affinity maturation of this CDR in vivo. However, a twofold improvement in affinity was observed for both single and double amino acid changes at two positions in the middle of the CDR. Moreover, a 10-fold increase in affinity for IL-1 beta was achieved by combining two of the phage-selected single amino acid substitutions in CDR3-H, thereby demonstrating that a significant improvement in affinity can be achieved through CDR mutagenesis, even in a matured Ab. The increased affinity of this Fab did not, however, enhance its neutralizing activity in vitro.
Amino Acid Sequence↗
Strategic planning of obstetric services: the Australian way.
This paper presents a number of documents developed at State and Territory Government level including the 'Shearman Report' concerning the strategic planning of obstetrical services. The papers are presented in chronological order. The aims, objectives and implementation arising from the reports are discussed including the mechanism by which the various studies were undertaken. The author acknowledges the existence of the many other reports relating to strategic planning for obstetrical services which were not able to be discussed due to the constraints of the presentation.
Australia↗
Gi alpha 1 selectively couples somatostatin receptor subtype 3 to adenylyl cyclase: identification of the functional domains of this alpha subunit necessary for mediating the inhibition by somatostatin of cAMP formation.
A major cellular action of the neuropeptide somatostatin (SRIF) is the inhibition of adenylyl cyclase activity. SRIF induces this effect after its interaction with membrane-bound receptors. Five SRIF receptors (SSTRs), which differ in their functional coupling to adenylyl cyclase, have recently been cloned. The third SSTR cloned, SSTR3, effectively mediates the inhibition of adenylyl cyclase by SRIF. The molecular mechanism by which SRIF modulates intracellular cAMP synthesis via SSTR3 was investigated by initially identifying which G alpha subunits are involved in coupling SSTR3 to adenylyl cyclase. SRIF did not inhibit cAMP formation in Chinese hamster ovary cells stably expressing SSTR3 and Gi alpha 2 or Gi alpha 3 but lacking Gi alpha 1. However, SRIF did inhibit forskolin-stimulated cAMP formation in Chinese hamster ovary cells stably expressing SSTR3 and Gi alpha 1, indicating that Gi alpha 1 selectively couples SSTR3 to adenylyl cyclase. To investigate the functional domains of Gi alpha 1 necessary for interaction with SSTR3, a chimeric alpha subunit (Gi alpha 2/Gi alpha 1) was constructed, consisting of the amino-terminal two thirds of Gi alpha 2 ligated to the carboxyl-terminal third of Gi alpha 1. SRIF inhibited cAMP formation in cells expressing SSTR3 and the Gi alpha 2/Gi alpha 1 chimera. These findings indicate that the carboxy-terminal third of Gi alpha 1 interacts with SSTR3 and is important in transmitting the signal of SSTR3 activation to adenylyl cyclase. In contrast, a similar Gi alpha 2/Gi alpha 3 chimera did not couple SSTR3 to adenylyl cyclase, further indicating that Gi alpha 3 does not contribute to SRIF inhibition of adenylyl cyclase activity. These findings demonstrate that Gi alpha 1 selectively couples SSTR3 to adenylyl cyclase, and they indicate that the carboxyl-terminal region of this alpha subunit is involved in mediating SRIF inhibition of adenylyl cyclase activity.
Adenylyl Cyclases↗
Nortriptyline in the hospitalized elderly: tolerance and side effect reduction.
This article describes two separate but related studies regarding the use of nortriptyline (NT) in the treatment of depressed elderly inpatients. The first study assesses medication tolerance to NT during the acute treatment of late-life depression. The second describes a placebo-controlled study of the effect of bethanechol in reducing antimuscarinic side effects of NT. Antidepressant pharmacotherapy was considered for 72 patients with late-life depression; 17 (24%) did not receive NT; 5 (7%) because of absolute or relative medical contraindications. Of the 55 patients who started on NT, 9 percent had side effects that necessitated medication discontinuation. A separate sample of 26 elderly depressed patients being treated with NT participated in a double-blind, placebo-controlled trial of bethanechol. Patients receiving bethanechol had reduced subjective complaints of anticholinergic side effects and showed improvement on an objective measure of salivary flow.
Aged↗
Evaluation of new anti-infective drugs for the treatment of intraabdominal infections. Infectious Diseases Society of America and the Food and Drug Administration.
These guidelines deal with the evaluation of anti-infective drugs for the treatment of intraabdominal infections. The clinical entities consist of infections arising from any part of the gastrointestinal tract, from the distal esophagus to the colon. These include surgical infections of the bowel, biliary tree, liver, spleen, and pancreas. Virtually all intraabdominal infections are due to multiple microorganisms resident in the gastrointestinal tract; these include aerobes and facultative and obligate anaerobes. Infections are classified as complicated (requiring an operative procedure), uncomplicated (managed medically), and postoperative wound (the operative procedure should be curative, but anti-infective drugs are used to prevent further infection at the site). Clinical criteria are paramount for entry into a study and for evaluation of efficacy. For complicated infections an adequate operation is an important determinant of outcome and needs assessment. Cultures of purulent intraabdominal fluid or abscess material are the only valid microbiologic indicators of infection. The acute physiology and chronic health evaluation score is useful in defining the severity of acute illness. The control regimen should consist of effective, established drugs and surgical procedures for the condition. Duration of therapy for complicated infections is usually 5-14 days; for uncomplicated infections, 3-7 days; and for postoperative wound infection, 2-5 days. Periodic assessment of safety and efficacy must be conducted during therapy. The outcome at final assessment is cure, failure, or indeterminate.
Anti-Infective Agents↗
Evaluation of new anti-infective drugs for the treatment of acute pelvic infections in hospitalized women. Infectious Diseases Society of America and the Food and Drug Administration.
This set of guidelines deals with evaluation of anti-infective drugs for treatment of acute pelvic infections in hospitalized women. The clinical entities include infectious complications of cesarean section; elective hysterectomy; and septic, incomplete abortion. Conditions including endomyometritis, cuff cellulitis, pelvic cellulitis, parametritis, phlegmon, and pelvic abscesses may arise due to a variety of bacterial species, both aerobic and anaerobic, that comprise the endogenous flora of the lower reproductive tract. Anaerobic bacteria have assumed particular importance, and therapy should be directed against such organisms. The roles of enterococci, chlamydiae, and mycoplasmas remain uncertain. Culture samples must be obtained under conditions assuring minimal vaginal contamination. Before a new drug may be used for treatment of human pelvic infections, considerable information is necessary about its antimicrobial spectrum as well as its safety and efficacy. Placebo-controlled trials are considered unethical. Historical controls may be used, but concurrent active control comparative trials are preferred. Parenteral administration is recommended for at least the initial 4 days of therapy, but orally administered drugs may be evaluated for completion of longer courses. The expected cure rate is approximately 90%. Uncomplicated infections should be treated for at least 4 days; more complicated infections may require prolonged therapy. Although clinical cure is paramount, microbiologic response must also be taken into account. In the final assessment, outcome will be classified as cure, failure, or indeterminate.
Acute Disease↗
Transformation of mammalian cells with genes from prokaryotes and eukaryotes. 1979.
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Animals↗
A region in domain 1 of CD4 distinct from the primary gp120 binding site is involved in HIV infection and virus-mediated fusion.
The high affinity binding site for human immunodeficiency virus (HIV) envelope glycoprotein gp120 resides within the amino-terminal domain (D1) of CD4. Mutational and antibody epitope analyses have implicated the region encompassing residues 40-60 in D1 as the primary binding site for gp120. Outside of this region, a single residue substitution at position 87 abrogates syncytium formation without affecting gp120 binding. We describe two groups of CD4 monoclonal antibodies (mAbs) which recognize distinct epitopes associated with these regions in D1. These mAbs distinguish between the gp120 binding event and virus infection and virus-induced cell fusion. One cluster of mAbs, which bind at or near the high affinity gp120 binding site, blocked gp120 binding to CD4 and, as expected, also blocked HIV infection of CD4+ cells and virus-induced syncytium formation. A second cluster of mAbs, which recognize the CDR-3 like loop, did not block gp120 binding as demonstrated by their ability to form ternary complexes with CD4 and gp120. Yet, these mAbs strongly inhibited HIV infection of CD4+ cells and HIV-envelope/CD4-mediated syncytium formation. The structure of D1 has recently been solved at atomic resolution and in its general features resembles IgVk regions as predicted from sequence homology and mAb epitopes. In the D1 structure, the regions recognized by these two groups of antibodies correspond to the C'C" (Ig CDR2) and FG (Ig CDR3) hairpin loops, respectively, which are solvent-exposed beta turns protruding in two different directions on a face of D1 distal to the D2 domain. This face is straddled by the longer BC (Ig CDR1) loop which bisects the plain formed by C'C'' and FG. This structure is consistent with C'C'' and FG forming two distinct epitope clusters within D1. We conclude that the initial interaction between gp120 and CD4 is not sufficient for HIV infection and syncytium formation and that CD4 plays a critical role in the subsequent virus-cell and cell-cell membrane fusion events. We propose that the initial binding of CD4 to gp120 induces conformational changes in gp120 leading to subsequent interactions of the FG loop with other regions in gp120 or with the fusogenic gp41 potion of the envelope gp160 glycoprotein.
Antibodies, Monoclonal↗
Humoral response of cynomolgus macaques to human soluble CD4: antibody reactivity restricted to xeno-human determinants.
The CD4 cell surface glycoprotein which is expressed primarily by a subset of T lymphocytes plays a key role in normal immune responses. In the immunopathogenesis of AIDS, it serves as the high-affinity receptor for HIV, facilitating viral attachment and entry into CD4+ cells. As such, the truncated soluble form of this molecule (sT4) has been proposed as a therapeutic drug for the treatment of AIDS whereby it would act as decoy for viral entry into cells or facilitate elimination of soluble viral envelope glycoprotein. In a study designed to look at the effect of sT4 on immune function, sT4 was administrated to experimentally naive primates. In this report, we show that administration of sT4 to cynomolgus macaque monkeys over a period of up to 3 weeks results in antibody responses with specificities for human CD4 molecules. Antisera thus generated bound sT4 and cell surface CD4 expressed on human T lymphocytes but failed to bind to cynomolgus lymphocytes. These antibodies caused no apparent adverse effects on normal immune functions of the cynomolgus macaques. We conclude from these data that the antibody response to soluble CD4 in cynomolgus monkeys is directed at determinants present on human CD4 but absent on monkey CD4. The restricted xenogeneic specificity of the antibody response indicates that soluble CD4 may not be highly immunogenic in syngeneic hosts. The present study also shows that these antibodies can block HIV-induced syncytium formation indicating that the antibodies bind to regions on the CD4 molecule close to the HIV-env gp120 binding site. The gp120 binding site, which resides within the N-terminal V1 domain of CD4, encompasses a region which corresponds to the complementarity determining regions (CDRs) of immunoglobulins. The CDR-like regions of CD4-V1 manifest the greatest species divergence, are tolerant to experimental in vitro mutagenesis, and generate the predominant antibody response in mice immunized with human CD4 indicating that differences in the V1 sequence between human and other non-human primates may localize to this regions.
Animals↗
Macrophage-tropic strains of human immunodeficiency virus type 1 utilize the CD4 receptor.
To characterize the role of CD4 in human immunodeficiency virus type 1 (HIV-1) infection of macrophages, we examined the expression of CD4 by primary human monocyte-derived macrophages and studied the effect of recombinant soluble CD4 and anti-CD4 monoclonal antibodies on HIV-1 infection of these cells. Immunofluorescence and Western blot (immunoblot) studies demonstrated that both monocytes and macrophages display low levels of surface CD4, which is identical in mobility to CD4 in lymphocytes. Recombinant soluble CD4 and the anti-CD4 monoclonal antibody Leu3a blocked infection of macrophages by three different macrophage-tropic HIV isolates, and the cytopathic effects of HIV-1 infection were similarly prevented. Dose-response experiments using a prototype isolate which replicates in both macrophages and T lymphocytes showed that recombinant soluble CD4 inhibited infection of macrophages more efficiently than in lymphocytes. These results indicate that CD4 is the dominant entry pathway for HIV-1 infection of macrophages. In addition, recombinant soluble CD4 effectively blocks HIV-1 infection by a variety of macrophage-tropic strains and thus has the potential for therapeutic use in macrophage-dependent pathogenesis in HIV disease.
Antibodies, Monoclonal↗
Structural analysis of the human immunodeficiency virus-binding domain of CD4. Epitope mapping with site-directed mutants and anti-idiotypes.
The CD4 molecule, a differentiation marker expressed primarily by T lymphocytes, plays an important role in lymphocyte activation. CD4 is also the receptor for HIV. A number of recent studies have localized the high affinity binding site of the HIV envelope glycoprotein, gp120, to the NH2-terminal (V1) domain of CD4, a region with sequence and predicted structural homology with Ig kappa chain V domains (V kappa). In this report, we show that V1 bears structural similarities with V kappa regions through detailed epitope mapping of 26 CD4 mAbs. The binding sites of these mAbs were initially defined relative to one another by crossblocking analysis and were then localized to specific domains of CD4 in blocking studies with truncated, soluble CD4 proteins. The epitopes within the V1 domain were mapped in detail with a panel of 17 substitution mutants, and the specificities of several mAbs that appear to recognize very similar epitopes were examined in crossblocking studies with anti-idiotype antibodies. The location of the epitopes is consistent with a V kappa-like structure of V1. Most of the epitopes lie within regions of predicted exposed loops. A number of these epitopes span discontinuous residues in the linear sequence that lies in close proximity in an Ig fold. Alignment of CD4 V1 with the Ig V kappa chains places these epitopes within stretches corresponding to the complimentarity-determining regions. This epitope analysis is relevant for a vaccine strategy for HIV based on anti-idiotype antibodies to CD4 mAbs and for studies with CD4 antibodies on the role of CD4 in T lymphocyte activation.
Amino Acid Sequence↗
Regulated expression at high copy number allows production of a growth-inhibitory oncogene product in Drosophila Schneider cells.
The Drosophila metallothionein promoter (Mtn) was used to obtain efficient, regulated expression of foreign gene products inserted in high copy numbers into Drosophila melanogaster Schneider 2 cells. An expression unit comprised of a reporter gene [Escherichia coli galactokinase (galK)] fused to the Mtn promoter was stably introduced into Schneider 2 cells in up to several hundred copies per cell in a single transfection-selection event. This system contrasts dramatically with other eukaryotic systems that permit only a few copies of a gene to be stably inserted in a single transfection-selection event. The transfected Drosophila S2 cell lines expressed high levels of both galK mRNA and protein in response to metal induction. Most important, and in contrast to mammalian cells, expression remained fully regulated even at high copy number, with low basal expression maintained in the absence of inducer. This regulated system was used to obtain efficient expression in Drosophila cells of an otherwise lethal or growth-inhibitory gene product, the human H-ras oncogene. The ability to obtain regulated high-level expression of potentially lethal foreign proteins is unique to the Drosophila cell system.
Animals↗
Microflora of the urethra in adolescent boys: relationships to sexual activity and nongonococcal urethritis.
Urethral cultures were obtained from 90 adolescent youth, 16 of whom denied previous sexual activity. Among the sexually active boys was a group of 32 with clinically significant pyuria, consistent with the diagnosis of urethritis, on a first-part urinalysis (FPU) specimen. To relate differences in urethral microflora to sexual activity, 42 sexually active patients with a negative FPU were compared with the never sexually active group. The profile of anaerobic, but not aerobic, bacteria isolated from the urethra was related to the presence or absence of previous sexual activity. Mycoplasma species and Ureaplasma urealyticum were isolated from sexually active patients only, and may be markers of sexual activity in adolescent boys. Of the 32 patients with FPU evidence of urethritis, 22 (69%) had cultures positive for Chlamydia trachomatis, and an additional three (9%) had cultures positive for Neisseria gonorrhoeae. The findings in sexually active patients with a positive FPU were otherwise similar to those of sexually active patients without evidence of urethritis. C. trachomatis appears to be the most important agent of urethritis among adolescent boys with a positive FPU.
Adolescent↗
Cefotetan in the treatment of obstetric and gynecologic infections.
The efficacy, tolerance, and safety of cefotetan--a new 7-alpha-methoxy cephalosporin--was assessed in controlled and uncontrolled evaluations involving 131 evaluable patients hospitalized with obstetric and gynecologic infections. The 99% satisfactory clinical response rate obtained with this drug was equivalent to that obtained with either moxalactam or cefoxitin, yet the mean amount of cefotetan given was lower than that of the other two drugs. Cefotetan was well tolerated and produced no major adverse reactions. In this era of Diagnosis Related Groups and cost containment, the twice-daily dosage schedule of cefotetan is a decided cost benefit.
Adult↗