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Biomedical subjects

G W Fischer

Publications and source records attributed to G W Fischer.

At least 37 records · Page 2Linked to original sources
PubMed1992

Early-onset group B streptococcal sepsis: a current assessment.

Group B streptococcus (GBS) is a common cause of early-onset sepsis in neonates. The most recent reviews describing incidence, diagnosis, treatment, and outcome evaluated data on patients from the early 1980s. To obtain current information about this disease, we retrospectively evaluated data on neonates with GBS early-onset sepsis from nine hospitals in the United States between Jan. 1, 1987, and Dec. 31, 1989. There were 245 infants with GBS bacteremia identified among 61,809 live births, resulting in an incidence of 0.32%. Ninety-six infants (39%) were preterm (less than 38 weeks of gestational age). Maternal risk factors for infected preterm and term infants were similar. Antibiotics were administered during parturition in 10% of infants with bacteremia. Mothers of preterm infants received antibiotics up to 48 hours before delivery; mothers of term infants received antibiotics less than 4 hours before delivery. All preterm infants with bacteremia had symptoms; 22% of term infants with bacteremia had no symptoms. Group B streptococcal meningitis was confirmed in 6.3% of infants. Although 86% survived, GBS sepsis increased the birth weight-specific mortality rate up to eightfold in preterm infants and more than 40-fold in term infants. Although the incidence of GBS early-onset sepsis is not changing, we speculate that the improved birth weight-specific survival rate and the changing clinical presentation are due to improved intrapartum and neonatal management.

Bacteremia↗
PubMed1992

Catheter-associated sepsis caused by Ochrobactrum anthropi: report of a case and review of related nonfermentative bacteria.

Ochrobactrum anthropi, formerly known as CDC group Vd, is an oxidase-producing, gram-negative, non-lactose-fermenting bacillus that oxidizes glucose and grows readily on MacConkey agar. Only occasionally isolated from human clinical specimens, this organism has rarely been found to be pathogenic. We describe the first reported case of infection due to O. anthropi in a child, that of bacteremia in a 3-year-old girl undergoing chemotherapy for retinoblastoma. In addition, we review the literature concerning cases of infection due to this and closely related bacterial species, namely Alcaligenes xylosoxidans subspecies xylosoxidans, Agrobacterium radiobacter, and "Achromobacter" group B. Finally, we attempt to clarify the confusing history and taxonomy of these organisms as well as make recommendations regarding antimicrobial therapy for infections caused by them.

Anti-Bacterial Agents↗
PubMed1992

Risk perception and the value of safety.

This paper examines the relationship between perceived risk and willingness-to-pay (WTP) for increased safety from technological hazards in both conceptual and empirical terms. A conceptual model is developed in which a given household's WTP for risk reductions is a function of traditional socioeconomic variables (i.e., income and base level of risk) and perceived characteristics of the hazards (i.e., dread, knowledge, and exposure). Data to estimate the model are obtained through a combined contingent valuation and risk perception survey that considers 10 technological hazards, five of which are well-defined (e.g., death rates are known and the risks are relatively common) and five are less well-defined. Econometric results, using TOBIT estimation procedures, support the importance of both types of variables in explaining WTP across all 10 hazards. When the risks are split into two groups, the results show that WTP for well-defined hazards is most influenced by perceived personal exposure, while WTP for less well-defined risks is most influenced by levels of dread and severity.

Data Collection↗
PubMed1992

Immunoglobulin therapy in older infants and children.

The availability of intravenous immunoglobulin preparations and human monoclonal antibodies has broadened the potential utility of antibody therapy to include treatment of viral infections such as cytomegalovirus and respiratory syncytial virus and prevention and treatment of serious bacterial infections such as endotoxic shock and pneumonia in children with acquired immunodeficiency syndrome. As new polyclonal and monoclonal immunoglobulin preparations are developed for specific organisms or clinical settings, immunoglobulin therapy is likely to become an increasingly important component of the clinician's armamentarium.

Bacterial Infections↗
PubMed1991

Preferences for separating or combining events.

This research investigates people's preferences for temporally separating or combining emotionally impactful events. For instance, do people prefer to experience 2 negative events (e.g., manuscript rejections) on the same day or on different days? Do people prefer to experience 2 positive events (e.g., manuscript acceptances) on the same or different days? This article proposes a renewable resources model that combines elements of decision-making models (prospect theory) with the notion that people possess limited but renewable physiological, cognitive, and social resources for dealing with emotionally impactful events. As predicted, Ss preferred to separate 2 positive events (the gain-savoring hypothesis), to separate 2 negative events (the multiple-loss-avoidance hypothesis), and to combine a positive and a negative event (the loss-buffering hypothesis). Ss displayed identical preferences for events from the academic, financial, and social domains.

Activities of Daily Living↗
PubMed1991

Comparative protective activity of human monoclonal and hyperimmune polyclonal antibody against group B streptococci.

Group B streptococcal (GBS) infections cause significant morbidity and mortality in neonates and compromised hosts, who usually lack opsonic antibody to their infecting strain. Unfortunately, most conventional immunoglobulin preparations possess little GBS antibody. The protective activity of a human monoclonal antibody (HuMAb) and a human hyperimmune intravenous immunoglobulin (HivIg) were evaluated against these organisms and compared with a conventional intravenous immunoglobulin (ivIg). The HuMAb and the HivIg possessed significant protective activity (50%-95%) against extremely virulent strains of types I, II, and III GBS in doses as low as 4-20 mg/kg. In contrast, the conventional ivIg had little protective activity against some of these strains in doses as high as 500 mg/kg. The opsonic activity of the HuMAb and HivIg also usually exceeded that of the conventional ivIg. These studies suggest HivIg or HuMAb with markedly enhanced specific activity may provide optimal immunotherapy for GBS infections.

Animals↗
PubMed1991

Comparison of commercially available group B streptococcal latex agglutination assays.

Detection of group B streptococcus (GBS) antigen in urine by latex particle agglutination (LPA) may facilitate the rapid diagnosis of GBS sepsis. We sought to compare three commercial LPA assays with specimens that were spiked with type-specific antigen, group-specific antigen, or type III organisms. There were sensitivity differences between the assays, but the Bactigen assay performed best, detecting as little as 1 ng of GBS group-specific antigen per ml in urine and as few as 10(5) CFU of GBS type III organisms per ml in urine, serum, and cerebrospinal fluid.

Adult↗
PubMed1990

Immunoglobulin therapy for neonatal sepsis: an overview of animal and clinical studies.

Bacteria such as Escherichia coli and group B streptococci are common neonatal pathogens. Neonates infected perinatally often develop overwhelming sepsis which may rapidly progress to shock and death in just a few hours. This fulminant course suggests that immunity to these bacteria is deficient. Studies from several laboratories have shown that antibody is important in immunity to group B streptococcus. In vitro studies have demonstrated that efficient phagocytosis and killing of these bacteria by neutrophils or monocytes requires opsonic antibody. Many premature babies have decreased amounts of total serum immunoglobulin G and term babies may not have sufficient levels of group B streptococcal antibodies to be protected. Immune globulin that contains adequate opsonic antibody to group B streptococcus may therefore be of value as adjunctive therapy for treating infections with these bacteria and may reduce the morbidity and mortality associated with group B streptococcal infection in high-risk neonates. Although intravenous immune globulin has been used to both prevent and treat infections in neonates, only limited efficacy data are available. Several large, blinded, and controlled studies that are being completed and analyzed will be important to determine the role of immune globulin therapy in neonates.

Animals↗
PubMed1990

Therapeutic intervention of clinical sepsis with intravenous immunoglobulin, white blood cells and antibiotics.

Antibiotics are the mainstay of therapy for acute bacterial infections. However, recent studies have suggested that adjunctive therapy designed to augment host immunity, might reduce morbidity and mortality. Many bacterial pathogens such as Haemophilus influenzae, Streptococcus pneumoniae and Group B streptococcus are encapsulated and require opsonic antibody to promote efficient phagocytosis and killing by neutrophils. Children with bacterial sepsis may be deficient in both of these components of immunity. This is a particularly serious problem in premature babies who may not receive protective amounts of antibodies from their mothers, since most antibody crosses the placenta in the last 4-6 weeks of pregnancy. Septic infants may also deplete their neutrophil reserves and develop neutropenia during infection. Since efficient clearance of encapsulated bacteria require both neutrophils and antibody, these babies are at high risk for treatment failure even with appropriate antibiotic therapy. Several studies have analyzed the role of neutrophil transfusions and immunoglobulin therapy in septic infants. However, relatively few patients have been prospectively evaluated in controlled studies. In addition, the logistical problems related to rapidly collecting neutrophils for therapy of bacterial sepsis are considerable and have decreased the usefulness of this approach. The availability of intravenous immunoglobulin (IVIG) has made the use of immunoglobulin feasible even in rapidly progressing bacterial sepsis. Animal studies have demonstrated the potential usefulness of IVIG and studies in septic babies strongly suggest that IVIG as an adjunct to antibiotics might improve mortality in septic neonates. Further research is needed to improve the logistics of obtaining neutrophils and to improve the availability of pathogen-specific immunoglobulin preparations.

Anti-Bacterial Agents↗
PubMed1989

Investigations on the acute toxic, cytogenetic, and embryotoxic activity of phenyl isocyanate and diethoxyphosphoryl isocyanate.

Phenyl isocyanate (I) and diethoxyphosphoryl isocyanate (II), used as intermediates in organic chemical syntheses, were tested for their acute toxic, cytogenetic, and embryotoxic activity on mice of different strains. The oral LD50 values for male CFLP mice were determined to be 196 mg/kg for I and 4080 mg/kg for II. Single oral doses of 1/40 and 1/20, respectively, of the LD50 of I (4.9 and 9.8 mg/kg) and II (102 and 204 mg/kg) did not cause any significant enhancement in the percentage of chromosome aberrations in bone marrow cells of CFLP mice. After oral administration of 9.8 mg/kg I and 204 mg/kg II to pregnant Halle-AB-Jena and Halle-DBA mice at various days of gestation (4, 7, 11, or 15), none of the compounds tested were embryotoxic.

Animals↗
PubMed1989

Perceived distributions of the characteristics of in-group and out-group members: empirical evidence and a computer simulation.

This research studied 2 properties of perceived distributions of the characteristics of social category members: the probability of differentiating (making distinctions) among category members and the perceived variability (variance) of category members. The results of 4 experiments supported the hypothesis that greater familiarity with a social group leads to greater perceived differentiation and variability regarding that group. In-group members formed more differentiated and variable distributions for groups defined by age and more differentiated distributions for groups defined by nationality. For gender (where students were roughly equally familiar with people of both genders), no in-group--out-group differences occurred. Also, students perceived greater differentiation and variability among classmates over the course of a semester. To explain these results, we developed PDIST, a multiple exemplar model that assumes that people form perceived distributions by activating a set of category exemplars and then judging the relative likelihoods of different feature values on the basis of the relative activation strengths of these feature values. The results of a computer simulation experiment indicated that PDIST is sufficient to explain the results of our 4 experiments. According to the perceived distributions formed by PDIST, increasing familiarity leads to greater differentiation and variability, has a concave impact, and has greater impact on differentiation than on variability.

Adult↗
PubMed1989

Pharmacokinetics of intravenous immunoglobulin in neonates.

Intravenous immunoglobulin (IVIG) may be a therapeutic adjunct to antibiotic treatment of neonatal infections. We examined the pharmacokinetics and safety of IVIG in human neonates. Thirty neonates with suspected sepsis were randomly assigned either to a treatment (receiving either 250, 500, or 1,000 mg/kg of IVIG plus antibiotics) or control (antibiotics alone) group. The 500 mg/kg dose produced a rise in total IgG for greater than 8 and in group B streptococcus (GBS) type-specific IgG for greater than 4-14 days. The type-specific antibody elevation varied with the amount of pathogen-specific antibody and dose of IVIG. Pharmacokinetic analysis suggests a Vdss of 42 ml/kg, Cl of 3.0 ml/kg/day, a biphasic elimination curve, and a terminal elimination half-life of 24.2 days. No toxicity was observed. These data may be valuable in determining optimal dosing schedules for IVIG in treating or preventing neonatal infections.

Anti-Bacterial Agents↗
PubMed1988

Therapeutic uses of intravenous gammaglobulin for pediatric infections.

Immunoglobulin plays a critical role in the immune response to many pediatric illnesses. We have just begun to explore the potential uses of IVIG in the prevention and treatment of pediatric diseases. The ability to give large amounts of antibody quickly and with repeated doses will allow physicians to achieve and maintain very high levels of serum antibody. IVIG may be valuable in restoring humoral immune deficiency, treating a number of viral and bacterial infections, and modulating immune responses. It will be important to analyze carefully the effectiveness of IVIG therapy using well-designed, controlled trials and to have specific IVIG preparations with defined activity and high levels of pathogen-specific antibody.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Circulating and storage neutrophils in septic neonatal rats treated with immune globulin.

Marked neutropenia, complete depletion of the neutrophil storage pool, and death within 48 h were observed in newborn rats intrapulmonically inoculated with 10(5) type III group B streptococci (GBS). Intraperitoneal administration of 225 mg of intravenous human immune globulin (IVIG) immediately after intrapulmonic inoculation of GBS significantly lessened the degree of neutropenia and prevented depletion of the neutrophil storage pool and death. No effect of IVIG on neutrophil production was observed in vitro, in cultures of granulocytic progenitor cells, or in vivo, as assessed by quantifying circulating and storage pools in normal neonatal rats injected with IVIG. IVIG, however, markedly hastened release of neutrophils from the reserves into the blood and hastened the arrival of neutrophils at the site of the bacterial injection (the right lung). Specific antibody to GBS, as opposed to a nonspecific IgG effect, appeared to be responsible for the improvements in neutrophils kinetics and for survival of the animals.

Animals↗
PubMed1988

Respiratory syncytial virus infections and intravenous gamma-globulins.

The respiratory syncytial virus (RSV) is a common cause of bronchiolitis and pneumonia in infants and young children. Throughout the world annual RSV epidemics result in numerous hospitalizations, substantial morbidity and some mortality. Until the recent introduction of ribavirin only supportive therapy has been available for treating these infections. The development of animal models of RSV infection and the observation that some lots of immunoglobulin prepared for intravenous administration contained substantial RSV-neutralization antibody titers, prompted a series of studies examining the safety and efficacy of immunoglobulin prepared for intravenous administration in the prophylaxis and treatment of RSV infections. This discussion will review our published, or soon to be published, studies on the use of Sandoglobulin for both immunoprophylaxis and immunotherapy of RSV infections in cotton rats. It will summarize studies utilizing both parenteral and topical (tracheal) Sandoglobulin therapy for RSV infections in owl monkeys. Finally the results of a small double blind trial of parenteral albumin or Sandoglobulin in the therapy of RSV bronchiolitis and/or pneumonia in hospitalized children will be reviewed. The data show that immunoprophylaxis and immunotherapy of RSV infections in laboratory animals was well-tolerated, was safe and induced highly significant reductions in RSV shedding from the lower respiratory tract. Further, immunotherapy of RSV infections in children was also well-tolerated, induced no short or long term evidence of toxicity or injury and caused significant improvements in oxygenation and reductions in RSV shed from the respiratory tract.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Immunoglobulin therapy of neonatal group B streptococcal infections: an overview.

Group B streptococci (GBS) are a major cause of sepsis and meningitis in newborn babies. Neonatal GBS infections are often rapidly progressive, suggesting that the immunity to GBS is deficient. Studies have shown that opsonic antibody is required for efficient phagocytosis and killing of GBS, and neonatal GBS infections have been associated with diminished levels of anti-GBS antibody. Intravenous immunoglobulin (IVIG) has been shown to provide protective immunity in experimental GBS infection models. However, lot to lot variation in opsonic antibody levels occurs in standard IVIG preparations. Recently hyperimmune anti-GBS IVIG has been prepared with high levels of opsonic and protective antibody to GBS. Hyperimmune IVIG preparations will allow physicians to give higher quantities of specific anti-GBS antibody without having to administer large fluid volumes or large amounts of nonspecific immunoglobulin. In addition specific immunoglobulin preparations will ensure that the IVIG contains reliable antibacterial activity. Although human studies are limited they suggest that IVIG therapy in neonates may be safe and effective in treating neonatal sepsis. However, further studies are necessary to determine the role of IVIG in preventing or treating neonatal infections.

Animals↗