Alfred D. Heggie

Frequency and significance of isolation of Ureaplasma urealyticum and Mycoplasma hominis from cerebrospinal fluid and tracheal aspirate specimens from low birth weight infants

To investigate the pathogenicity of Ureaplasma urealyticum and Mycoplasma hominis in preterm infants, we conducted a study to determine (1) frequency of isolation from cerebrospinal fluid and tracheal aspirate specimens and (2) clinical outcomes and effect of erythromycin treatment in ureaplasma-colonized infants. From the cerebrospinal fluid of 920 infants, U. urealyticum was isolated from 2 (0.2%) and M. hominis from none. From tracheal aspirate specimens from 224 infants, U. urealyticum was recovered from 37 (17%) and M. hominis from 4 (2%). Demographic characteristics and clinical outcomes were compared in very low birth weight infants (< 1500 gm) who were culture-positive or -negative for U. urealyticum. Although infants with positive results were less mature than their cohorts with negative results, there were no substantive differences in clinical outcomes between the two groups. Initiation of erythromycin treatment of infants with positive ureaplasma culture results at a mean age of 16.4 days did not appear to alter the clinical outcome. We conclude that in preterm infants (1) infection of the cerebrospinal fluid by U. urealyticum is infrequent, (2) ureaplasma organisms are frequently present in tracheal aspirate specimens but do not appear to be related to the presence or the subsequent development of respiratory disease, and (3) initiation of erythromycin treatment at 1 to 3 weeks of age does not alter the clinical course.

Identification and quantification of ureaplasmas colonizing the respiratory tract and assessment of their role in the development of chronic lung disease in preterm infants

Background. The role of Ureaplasma urealyticum in the development of chronic lung disease (CLD) in preterm infants continues to be disputed. Recently U. urealyticum has been found to consist of two species, U. urealyticum and Ureaplasma parvum, a finding that has not been considered in previous studies of CLD. This study examined the possible relationships between development of CLD and respiratory colonization by these newly redefined species, their concentrations in lower respiratory secretions and the effect of pulmonary surfactant treatment on these relationships in preterm infants with birth weights <1500 g. Methods. Endotracheal aspirates (ETA) were collected from intubated infants when airway suctioning was medically required. ETA were stored at −80°C until quantitative cultures for ureaplasmas and Mycoplasma hominis were performed. Culture results were correlated with development of CLD. Results. Of 475 infants (birth weights <1500 g) admitted during the 2-year study period, 272 were excluded because they were not intubated or were extubated before ETA could be obtained. An additional 28 infants died, were discharged or were transferred before they could be assessed for CLD. From the remaining 175 infants ureaplasmas were isolated from 66 (38%). No statistically significant associations were identified between development of CLD and the Ureaplasma species isolated, or concentration of ureaplasmas in lower respiratory secretions. These findings were not altered by treatment with pulmonary surfactant (Survanta). Conclusion. Lower respiratory colonization by ureaplasmas does not appear to be a contributory cause of CLD in preterm infants.

Effects of Viral Exposure of the Two-Cell Mouse Embryo on Cleavage and Blastocyst Formation In Vitro

Summary: The effect of viral exposure of two-cell mouse embryos on their capacity to undergo subsequent cleavage and blastocyst formation in vitro was determined. Exposure to Coxsackie viruses B-4 and B-6, reovirus type 2, influenza virus type A, mouse cytomegalovi-rus, adenovirus type 5, and mouse adenovirus resulted in statistically significant inhibition of blastocyst formation. Development in vitro was unaffected by exposure to ECHO virus type 11, attenuated poliomyelitis virus type 2, parainfluenza virus type 1, mumps, rubella, and herpes simplex viruses types 1 and 2. Blastocyst formation was also unaffected by exposure of embryos to mouse interferon in a concentration 24 units/ml of culture fluid. Coxsackie virus B-4 was recovered from exposed embryos.Speculation: Arrest of cleavage in the preimplantation embryo may be the mechanism by which some maternal viral infections induce reproductive failure. Exposure of embryos to certain viruses, however, fails to interfere with cleavage or blastocyst formation. Further studies are required to determine if these apparently unaffected embryos have sustained occult injury which may result in abnormal development at later stages of gestation.

Rapid detection of herpes simplex virus in culture by in situ hybridization.

Detection of herpes simplex virus (HSV) by a newly developed HSV-DNA in situ hybridization (ISH) technique (Diagnostic Hybrids, Inc., Athens, OH, USA) was compared with a reference standard that combines observation for cytopathic effect in shell vial cultures with subsequent identification of virus by staining with fluorescein-labeled HSV-specific monoclonal antibody. The new technique utilizes a probe consisting of an alkaline phosphatase direct labeled, cloned, single stranded DNA fragment that is common to HSV-1 and HSV-2. Both methods include enhancement of infection by centrifugation. In concurrent testing of 98 freshly collected specimens, HSV was detected in 17 by culture and 16 by ISH. In testing of 57 frozen positive specimens, HSV was detected in 54 by culture and 53 by ISH. Of the total isolates, 22 were HSV-1 and 49 were HSV-2. HSV was detected after 24 hrs of incubation by the DNA probe technique. Using the shell vial method as a reference standard, the new HSV-DNA ISH method had a sensitivity of 97.2%, specificity of 100%, positive predictive value of 100%, and a negative predictive value of 97.7%. HSV-DNA ISH appears to be a practical, sensitive, and specific technique for detection of HSV.

Experimental studies of carcinogenesis of the uterine cervix in mice

Abstract In conclusion, the histogenesis of cervical carcinomas induced in mice by coaltar hydrocarbons or inactivated herpes simplex virus, types 1 and 2, has been described. The lesions antedating the development of squamous cell carcinoma were similar to lesions encountered in patients with the same keratinizing type of carcinoma of the ectocervix. A theory for the development of the three grades of human cervical squamous cell carcinoma has been presented based on experimental and clinical data which demonstrate that each of the three grades of cancer consists of cells which resemble those of the tissue of origin and of the antecedent noninvasive lesion.

Experimental Rubella in Rhesus Monkeys.

Summary In an attempt to transmit rubella to rhesus monkeys, 6 yearling male animals from an isolated, and therefore presumably susceptible population, were inoculated by several routes with throat washings and acute phase sera from selected rubella patients. During 21 days of observation following inoculation, none of the animals showed any physical signs of rubella. Serial daily total and differential leukocyte counts showed leukopenia and lymphocytosis of slight degree. In none of the animals tested was neutralizing antibody to rubella virus demonstrable prior to inoculation, but neutralization tests performed on pre-inoculation and post-inoculation sera showed a significant rise in titer in 4 of the 6 animals inoculated. It is concluded, therefore, that rhesus monkeys are probably susceptible to infection with rubella virus, but that the infection is usually of the inapparent type.

Recrudescence of H. Influenzae Meningitis after Therapy with Ampicillin: Late Recurrence May Result From Diminishing Levels of Ampicillin in the Cerebrospinal Fluid Secondary to Decreasing Meningeal Permeability and Too Early Reduction in Dose

bies and Children’s Hospital, Cleveland, Ohio 44106. IT is becoming common practice in many clinics to use ampicillin alone to treat bacterial meningitis in infants and children. Ampicillin is a useful drug because it is effective against the organisms most frequently encountered, can be administered orally or parenterally and, with the exception of hypersensitivity phenomena, has a low toxicity. The past ~ear. has seen reports of patients treated with ampicillin for H. influenzae meningitis who responded at first but who sub-

Intrauterine infection in maternal rubella

Intrauterine rubella infection was demonstrated in 18 (40.9 per cent) of 44 womenwhose pregnancies were terminated by medical intervention because of first trimester rubella. The frequency of intrauterine infection could not be related to the gestational age of the embryo at the onset of maternal rubella or to the duration of the interval between maternal infection and termination of pregnancy. No cytological abnormalities were observed in tissue cultures of products of conception shown to be infected by rubella virus.

Induction of cervical neoplasia in the mouse by an extract of cells infected by varicella-zoster virus

Since several human herpesviruses, including varicella-zoster virus (VZV), have been demonstrated to transform mammalian cells in vitro, VZV was tested in a mouse model of virus-induced cervical neoplasia to determine whether it is oncogenic in vivo. Herpes simplex viruses types 1 and 2 and cytomegalovirus have been previously shown to induce cervical neoplasia in this mouse model. VZV was propagated in WI-38 cell cultures and inactivated by ultraviolet irradiation. Control material was prepared in an identical manner from uninfected cell cultures. Cotton tampons, saturated with inactivated virus or control material, were inserted into the vaginas of C57BL mice three times a week for 60 weeks. Cervical dysplasia was detected in 40% and invasive carcinoma in 34% of virus-exposed mice by histological examination. No lesions were detected in control animals. These observations indicate that VZV, or some product of virus-infected cells, is oncogenic in vivo for the mouse cervix.

Cell-Mediated Immune Responses to Chlamydia trachomatis in Mothers and Infants

Abstract Cell-mediated immunity to Chlamydia trachomatis was studied in pregnant women with chlamydial infection of the cervix, in infants born vaginally to these women, and in infants presenting with chlamydial conjunctivitis. Uninfected pregnant women and their infants were studied as controls. McCoy cell cultures were used to isolate C. trachomatis from clinical specimens. Cell-mediated immunity was measured by lymphocyte proliferative responses in vitro to stimulation by chlamydial antigens. Chlamydial IgG antibody in serum specimens was detected by a micro-enzyme-linked immunosorbent assay technique. The mean lymphocyte proliferative responses to chlamydial antigens were greater in infected women than in uninfected women both during pregnancy and in the postpartum period. Lymphocyte responsiveness in infected pregnant women, however, was less than in postpartum women. Despite failure to detect chlamydial infection in exposed infants, lymphocyte proliferative responses were greater in umbilical cord blood and later in peripheral blood samples from neonates born to infected mothers than in infants born to uninfected mothers. These responses were also greater in infants with chlamydial conjunctivitis than in infants of uninfected mothers. These data suggest that cellular immune responses to chlamydial antigens are increased in infected mothers and infants and that infants may acquire chlamydial cell-mediated immunity transplacentally.