Val Hemming

Fourteen patients who had repeated episodes of otitis media and diarrhea were evaluated to determine if a defect in the host defense mechanism could account for the unusual incidence of infection. Each of the patients with recurrent otitis media and diarrhea had a profound defect in neutrophil chemotactic responsiveness. The mean chemotactic index of the patients was 21 +/- 6, while that of 25 controls was 62 + 10. Other neutrophil functions, lymphocyte T-cell populations, immunoglobulins, and complement components were normal in the patients. Serum IgE levels were also normal. The presence of a defect in neutrophil chemotaxis in these patients with recurrent otitis media and chronic diarrhea suggests that the phagocyte may play an important role in protection of the mucosal surfaces of the respiratory and gastrointestinal tracts.

False-negative blood culture results may occur in children with pneumococcal bacteremia due to bacterial autolysis. We describe four patients with pneumococcal bacteremia whose aerobic blood cultures showed partial or complete autolysis of the pneumococci. Pneumococcal antigen, however, was rapidly detected in media from the blood culture bottles, using an agglutination assay. Processing of the media before analysis was necessary to prevent nonspecific agglutination and to allow the detection of a specific reaction. It is important that physicians and laboratory personnel be aware that pneumococci may rapidly autolyze during incubation, yielding false-negative culture results. Antigen detection methods may provide rapid and specific identification of the etiologic agent.

... TITLE: PREPARATION AND CHARACTERIZATION OF MOUSE AND HUMAN MONOCLONAL ANTIBODIES TO BOTULINUM TOXINS PRINCIPAL INVESTIGATOR: Kenneth W. Hunter Gerald W. Fisher Val G. Hemming ... 'We have obtained neri°•heral blood lymphocytes from a ...

The mechanisms of host resistance to group B streptococci have not been defined precisely. In the studies reported here we have assessed the contributions of both humoral and cellular factors in protection against strains of this group. With assays of specific opsonic activity based upon the production of polymorphonuclear leukocyte chemiluminescence and radiolabeled bacterial uptake, we have demonstrated that specific heat-stable antibody and the classic complement pathway are major factors in opsonization of these organisms. In the absence of specific antibody, fresh serum resulted in markedly reduced bacterial uptake indicating, at best, a minor role for the alternative complement pathway. Additional studies have indicated that strain-specific antiphagocytic factors as well as type-specific ones may play a role in the virulence of these organisms. Neonates who developed group B streptococcal sepsis usually lacked opsonic activity in their infecting strain. In addition, polymorphonuclear leukocytes from normal term and stressed neonates showed impaired metabolic activation as measured in the chemiluminescence assay following exposure to opsonized group B streptococci. These results suggest that neonates who develop group B streptococcal disease may have defects in both the humoral and cellular aspects of their acute inflammatory response which may contribute to the high mortality observed in this most fulminant of bacterial infections.

A 6-month-old male infant with a severe combined immunodeficiency syndrome was hospitalized for progressive respiratory distress. Examination during hospitalization disclosed widespread pulmonary infiltrates that did not respond to intensive therapy. The patient died eight days after admission. Autopsy disclosed Pneumocystis carinii pneumonia and widespread giant cell pneumonia. Respiratory syncytial virus (RSV) was grown from a lung specimen obtained at autopsy. Specific immunofluorescent staining of the cytoplasm of alveolar lining cells with RSV antiserum was demonstrated. The electron microscopic appearance of giant cells was compatible with RSV infection. The RSV should be added to the list of viruses causing giant cell pneumonia.

Short-term (0 to 30 minutes) physiologic responses of neonatal lambs infused with a trichloroacetic extract of a type III (strain 878) group B streptococcus (878-TCA) were studied. Bolus injections of 878-TCA were associated with pulmonary hypertension, peripheral arterial hypoxemia, and reductions in circulating white blood cell and platelet counts. These events were associated with a rise in plasma levels of prostaglandins F2 alpha and E and could be prevented by proper treatment with ibuprofen. Continuous infusions of 878-TCA were associated with a dose-dependent rise in systemic and pulmonary arterial pressures and a fall in arterial PO2. During infusion, inhibition of prostaglandin synthesis resulted in a return toward preinfusion values. The authors conclude that venous infusions of extracts of 878-TCA induce significant pulmonary and systemic arterial vascular perturbations in the neonatal lamb and that some of these alterations are associated with the release of prostaglandins or other arachidonic acid metabolites.

A dysfunction of the nonadrenergic noncholinergic inhibitory (NANCi) system has been invoked as a possible mechanism underlying or contributing to altered airway function. In the present study we assessed whether human respiratory syncytial virus (HRSV) infection affects the airways' neurally mediated contractile and relaxant (NANCi) responses in vitro. NANCi responses were studied on tracheal smooth muscle (TSM) segments obtained from young adult cotton rats, a well-established model for HRSV infection. To assess NANCi responses, TSM segments were removed and placed in tissue baths containing modified Krebs-Henseleit, atropine (1 x 10(-6) M) and propranolol (5 x 10(-6) M). After contraction with neurokinin A (1 x 10(-5) M), electrical field stimulation (EFS) was applied at stimulation frequencies ranging from 5 to 30 Hz. The NANCi responses were measured and expressed as the mean (+/- SE) percent relaxation. To evaluate neurally mediated contractile responses, full frequency response curves (0.5-30 Hz) to EFS were also performed. We found significantly decreased NANCi responses in TSM segments obtained from infected cotton rats (n = 12) compared with control animals (n = 9) (P < 0.002). Furthermore, the contractile responses to EFS were increased in infected animals compared with the control group (P = 0.0001). These findings demonstrate that HRSV infection leads to an enhanced contractile response to EFS and a significant decrease in NANCi response in cotton rat airways in vitro. This disruption of the neural control of airways may lead to the development of altered airway function.

To evaluate the safety and efficacy of respiratory syncytial virus immune globulin (RSVIG) in the prevention of severe respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) in infants born prematurely with or without bronchopulmonary dysplasia (BPD). Data from a prospective, blinded, randomized, multicenter trial during three consecutive RSV seasons involving 249 children. This analysis comprises 162 preterm children, of whom 102 had BPD. The 87 children with congenital heart disease (CHD) were excluded from this analysis. Children were randomized to receive monthly infusions of RSVIG 750 mg/kg (high dose), RSVIG 150 mg/kg (low dose), or no RSVIG: Results from the preterm infants with and without BPD who received RSVIG 750 mg/kg are contrasted with control infants who did not receive RSVIG: As compared with controls, high-dose RSVIG administration significantly reduced the incidences of RSV LRTI (P = .01) and moderate-to-severe LRTI (P = .006). RSV-associated hospitalization also was decreased (P = .06) as well as were total RSV-associated days in the intensive care unit (P = .05). Significantly fewer preterm infants developed severe RSV LRTI in the RSVIG group compared with controls (4/58 [7%] vs 14/58 [24%], respectively; P = .01). Adverse reactions occurred in 5% of RSVIG infusions. These were generally mild and included reversible fluid overload, transient fever, and decreases in oxygen saturation. There was one death unrelated to either RSV or RSVIG administration. Prophylaxis with RSVIG is safe and is currently the only effective means to prevent severe RSV LRTI in high-risk preterm infants.

At the heart of medical science is the responsibility for investigators and practitioners to use the scientific method to seek and apply new knowledge to better understand the mechanisms, diagnosis, treatment, and prevention of disease. At times it is difficult to differentiate hypothesis or speculation from documented fact. This essay describes an episode in human biology and medicine in which authoritative speculation evolved into dogma and impeded investigators' proper interpretation of data about the pathogenesis of respiratory syncytial virus (RSV) bronchiolitis in infants. Speculation-turned-dogma regarding RSV seriously impeded scientific progress regarding RSV disease for nearly a generation. Teachers, biomedical scientists, and medical practitioners must remain vigilant for unsubstantiated dogma that can seriously impede progress in the medical sciences.

Most physicians recognize the false-positive blood cultures (generally due to contamination) are common. Bacteria such as pneumococci, however, may rapidly die in broth cultures, and viable bacteria may not be identified. Several patients were observed with pneumococcal infections that had false-negative blood cultures 24 hours after inoculation. Hemolysis and methemoglobin formation in the bottle suggested bacterial growth within 12 hours after incubation, and blind subcultures at that time yielded pneumococci. Pneumococcal antigen could be detected in the blood culture bottles using counter-immunoelectrophoresis, even though subculture at 24 hours yielded no growth. Physicians and laboratory personnel should be aware that false-negative blood cultures may occur, particularly with certain bacteria such as Streptococcus pneumoniae, and that the blood culture bottles should be observed visually for the presence of brown sediment or hemolysis.

The group B Streptococcus is one of the most virulent organisms causing perinatal infection. Human amniotic fluid from the second and third trimesters was pooled and analyzed for electrolytes, protein, albumin, zinc, inorganic phosphorus, ferritin, lysozyme, and immunoglobulins. We inoculated replicates of specimens with known virulent strains of group B streptococci (893, 891, and 878) and Escherichia coli (C5) with Todd-Hewitt broth and normal saline solution used as controls. Group B streptococci strains 893 and 891 proliferated rapidly at rates similar to their rates in Todd-Hewitt Broth. Strain 878 grew at a rate slower than that of strains 893 and 891. The amniotic fluid specimens were similar with respect to factors reported as inhibitory to bacterial proliferation. Second- and third-trimester amniotic fluid supports the growth of group B streptococci as well as a culture medium optimized for bacterial growth. Strain-specific variance in group B streptococci growth rates in a...

Several authors have described the bacterial growth-altering properties of amniotic fluid. We examined Group B Streptococcus growth in aseptically obtained amniotic fluid in vitro after altering its zinc, phosphorus, and meconium contents. Zinc and phosphorus levels were calculated in amniotic fluid and in meconium. Separate solutions of zinc and phosphorus were added to yield concentrations of 0.7, 7.0, 70, and 700 mumol. The solutions were incubated with Group B Streptococcus III 893 and Escherichia coli C5 strains, and 24-hour growth curves were plotted. Meconium, 0.5 mg/ml, was added to each amniotic fluid + zinc and amniotic fluid + phosphorus solution, and growth curves were plotted. The rate of proliferation of Group B Streptococcus varied directly with the zinc concentration (700 = 70 greater than 7 greater than 0.7 mumol) and inversely with the phosphorus content (700 less than 70 less than 7 = 0.7 mumol). Meconium enhanced the proliferative effect of zinc and hindered the ...

Data on 109,312 singleton births at U.S. Army hospitals over 3 years were examined to determine differences in perinatal risk factors between infants with a diagnosis of sepsis confirmed by blood culture and those whose cultures remained negative. The incidence of confirmed sepsis (1.1/1000 live births) and the importance of perinatal complications and prematurity were consistent with other reported findings. No reliable indicators of bacteremia that could be used in conjunction with other clinical data were found. These findings support continued empiric therapy in infants at risk until infection can be verified by culture.

To evaluate the efficacy of high-titer intravenous respiratory syncytial virus immune globulin (RSVIG) in the treatment of children at high risk for severe RSV infection who were hospitalized with proven RSV. Infants and young children younger than 2 years with bronchopulmonary dysplasia, chronic lung disease, congenital heart disease, or prematurity (<32 weeks' gestational age), hospitalized with a history of lower respiratory tract infection (LRI) of less than 4 days, were enrolled in this study. Patients were randomized in a blinded fashion to receive either 1500 mg/kg RSVIG or placebo in equal volumes. They were evaluated daily for safety and respiratory scores and for RSV nasal shedding. One hundred seven high-risk children were randomized--54 in the RSVIG group and 53 in the placebo group. Of these children, 51 in each group were considered evaluable. Children with pulmonary disease, congenital heart disease, or prematurity were equally distributed between the two treatment groups. However, two important differences were found in baseline variables between the two groups: there were more patients in the placebo group who had histories of previous LRI and there was a trend toward more severe disease at study entry in the RSVIG group. This was manifested by a higher entry respiratory score in the RSVIG group than in the placebo group (3.4 +/- 0.2 vs 3.1 +/- .01). A higher proportion of children in the RSVIG group (47%) than in the placebo group (28%) required intensive care at entry and mechanical ventilation at study entry (31% RSVIG-treated vs 18% placebo-treated patients). No significant difference was found between groups in the mean unadjusted duration of hospitalization (RSVIG group, 9.10 +/- 1.18 days; control group, 8.17 +/- 1.08 days). When the mean was adjusted for entry respiratory score, likewise, no difference was observed between each group (8.41 +/- 0.97 vs 8.89 +/- .99 days). The lack of efficacy observed in the study primary endpoint was observed in all diagnostic groups. No differences between the RSVIG and placebo groups were observed in the following secondary endpoints: duration of intensive care unit stay, duration of intensive care unit stay for RSV, mechanical ventilation, or supplemental oxygen. No significant differences in adverse events were reported in the RSVIG group (16 children) when compared with the control group (10 children). RSVIG treatment was safe but not efficacious in the treatment of children with bronchopulmonary dysplasia, congenital heart disease, or premature gestation who were hospitalized with RSV LRI.

We detected a 24.6 per cent nosocomial infection rate (222 infections in 138 infants) among 904 infants hospitalized for over 48 hours in a regional newborn intensive-care during 41 months of surveillance. Surface infections accounted for 40.1 per cent of the total, pneumonia for 29.3 per cent, bacteremia for 14.0 per cent, surgical-wound infection for 8.1 per cent, urinary-tract infection for 4.5 per cent, and meningitis for 4.0 per cent. Staphylococcus aureus (47.3 per cent) and gram-negative enteric bacilli (45.1 per cent) were the most common organisms recovered. Nosocomial infection rates were significantly higher in infants with a birth weight less than 1500 g (P less than 0.001). The mortality rate in infants with any nosocomial infection was 33 per cent in contrast to 14 per cent in non-infected babies (P less than 0.001). Nosocomial infections are a major problem in newborn intensive-care units.

Newborn infants may have IgG deficiencies that increase their susceptibility to bacterial infection. To determine whether intravenous immune globulin (IVIG) therapy improves survival rates in early-onset sepsis, we prospectively entered 753 neonates (birth weight 500 to 2000 gm, gestation less than or equal to 34 weeks, age less than or equal to 12 hours) into a multicenter, double-blind, controlled trial. Blood culture specimens were obtained and infants randomly assigned to receive 10 ml (per kilogram) intravenously of a selected IVIG (500 mg/kg) or albumin (5 mg/kg) preparation. Maternal and neonatal risk factors were not different between groups. Thirty-one babies (4.2%) had early-onset sepsis; the causative organisms were group B streptococcus (12 babies), Escherichia coli (6), and others (13). Of these 31 neonates, 7 (23%) died. Total serum IgG was higher for 7 days after IVIG therapy than after albumin treatment (p less than 0.05). During these 7 days, 5 (30%) of 17 albumin-treated and none of 14 IVIG-treated patients died (p less than 0.05). The survival rate at 56 days of age, however, was not significantly improved. Group B streptococcus type-specific IgG antibody was significantly increased after IVIG treatment and appeared to be related to the amount of IVIG specific antibody. Infusion-related adverse reactions were less frequent in patients receiving IVIG therapy (0.5%) than in those receiving albumin. The IVIG therapy in neonates with early-onset sepsis, while reducing the early mortality rate, did not significantly affect the overall survival rate. Further studies are necessary to confirm these findings and to determine more effective therapeutic regimens.

To determine whether a single dose of intravenously administered immune globulin (IVIG) decreases late-onset sepsis in premature infants, we prospectively entered 753 neonates with birth weight 500 to 2000 gm, gestation < or = 34 weeks, and age < or = 12 hours into a multicenter, double-blind, controlled trial. Infants were randomly selected to receive a single intravenous infusion, 10 ml/kg, of either IVIG (500 mg/kg) or albumin (5 mg/kg) and were observed for 8 weeks for infection. Maternal and neonatal risk factors for infection did not differ between groups. Although serum IgG values before infusion were related to gestation (R = 0.62), the change in serum IgG or half-life of IgG after IVIG infusion was not (R < or = 0.09). The serum IgG concentration was increased (p < 0.05) in IVIG-treated patients for 8 weeks. There were 88 episodes of late-onset sepsis in 79 neonates (10.5%). Causative organisms included the following: Staphylococcus epidermidis (37 episodes), Enterococcus (9), Staphylococcus aureus (7), Candida (6), Escherichia coli (6), and multiple organisms (11). Sepsis, death, and death as a result of infection were unaffected by treatment. We conclude that a single infusion of IVIG, 500 mg/kg, shortly after birth was not effective prophylaxis for late-onset infection in premature neonates. Future studies of late-onset sepsis prophylaxis should consider IVIG with known pathogen-specific antibody concentrations against organisms causing these infections, in particular S. epidermidis.

We sought to characterize the human respiratory syncytial virus (RSV) subgroup-specific antibody response to primary infection with RSV. RSV isolates from 43 infants and young children were typed as either subgroup A (Long strain-like) or B (18537 strain-like) based on reactivity with monoclonal antibodies. Acute-phase or preinfection and convalescent-phase sera were collected from the 43 subjects and tested in an enzyme-linked immunosorbent assay using purified F and G glycoproteins from RSV subgroups A and B and by neutralization assay against both subgroups of RSV. Twenty-six individuals had rises in titer of antibody to F glycoprotein, 27 to G glycoprotein, and 28 had rises in titer of neutralizing antibody. The antibody responses to homologous and heterologous F glycoproteins were not significantly different. In contrast, homologous vs. heterologous antibody responses to G glycoprotein were significantly different, with 7.3% relatedness between the G glycoproteins of subgroups A and B. Analysis of neutralizing antibody responses revealed 31% relatedness.