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Biomedical subjects

J Hedrick

Publications and source records attributed to J Hedrick.

24 records · Page 2Linked to original sources
PubMed1995

Parvovirus B19 infection in hospital workers: community or hospital acquisition?

A suspected nosocomial outbreak of parvovirus B19 infection in a maternity ward was investigated in February 1994. Questionnaires were administered and sera collected from maternity ward staff (n = 91), other ward staff in the same hospital (n = 101), and maternity ward staff at a nearby hospital (n = 81). Blood donors (n = 265) were used as community controls. Recent infection (parvovirus B19 IgM positivity) in susceptible persons (parvovirus B19 IgG-negative or IgM-positive) was common among all 4 groups (23%-30%). This high rate of recent infection occurred during a large community outbreak of fifth disease. Environmental samples collected from a room where a stillborn parvovirus B19-infected fetus was delivered were positive for parvovirus B19 DNA. Thus, this suspected nosocomial outbreak actually reflected transmission outside the hospital, but contaminated environmental surfaces were identified as one potential source for transmission of parvovirus B19.

Antibodies, Viral↗
PubMed1995

Mycoplasma pneumoniae and Chlamydia pneumoniae in pediatric community-acquired pneumonia: comparative efficacy and safety of clarithromycin vs. erythromycin ethylsuccinate.

We evaluated 260 previously healthy children ages 3 through 12 years who had clinical signs and symptoms of pneumonia, radiographically confirmed. Patients were randomized 1:1 to a 10-day course of either clarithromycin suspension 15 mg/kg/day divided twice a day or erythromycin suspension 40 mg/kg/day divided twice a day or three times a day. Evidence of infection with Chlamydia pneumoniae was detected in 28% (74) of patients: 13% (34) by nasopharyngeal culture and 18% (48) by serology with the microimmunofluorescence assay. Evidence of infection with Mycoplasma pneumoniae was detected in 27% (69) of patients: 20% (53) by nasopharyngeal culture or polymerase chain reaction and 17% (44) by serology with the use of enzyme-linked immunosorbent assay. Serologic confirmation of infection was observed in 23% (8) and 53% (28) of patients with bacteriologically detected C. pneumoniae and M. pneumoniae, respectively. Treatment with clarithromycin vs. erythromycin, respectively, yielded the following outcomes: clinical success 98% (121 of 124) vs. 95% (105 of 110); radiologic success 98% (109 of 111) vs. 94% (92 of 110); and eradication by pathogen, C. pneumoniae 79% (15 of 19) vs. 86% (12 of 14) and M. pneumoniae 100% (9 of 9) vs. 100% (4 of 4). Adverse events were primarily gastrointestinal occurring in almost one-fourth of patients in both groups, and were mild to moderate in severity. Clarithromycin and erythromycin were similarly effective and safe for the treatment of radiographically proved, community-acquired pneumonia in children older than 2 years old.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1993

Effects of high-energy shock waves on rapidly proliferating cells: African clawed toad (Xenopus laevis) zygote model.

To date few studies have described the effects of high-energy shock waves (HESW) on benign, rapidly proliferating cells. In the African clawed toad (Xenopus laevis) model, previously described in vitro fertilization methods were used to study the effects of HESW on zygote cleavage and blastocytosis. Groups of 50 freshly fertilized ova were placed at the bottom of clear ultracentrifuge tubes filled with 5% DeBoers solution, positioned at the f2 focus utilizing the biprismatically split halogen red laser of a Dornier XL-1 experimental lithotripter, and treated using an 80-nF capacitor at various kilovoltages and shock wave (SW) numbers. Controls were treated in an identical fashion but kept outside the f2 focus. Cell lysis was the most notable finding at power settings in the standard treatment range (12 kV or greater). Increasing kilovoltage at a constant SW number (100) correlated linearly with the number of zygotes lysed in each group. There was an apparent logarithmic decrease in progression to cleavage and early development with increasing kilovoltage. At 10 kV, no effect on development was observed. Increasing SW numbers at a constant 19 kV correlated linearly with an increase in the number of lysed zygotes in each group. Increasing the SW number at constant kilovoltage correlated with an apparent logarithmic decrease in progression to cleavage and early development. This effect was observed with as few as 10 SW. These experiments have demonstrated a correlation between viability and lysis of zygotes with increasing treatment energies. The data suggest a threshold setting that minimally affects cellular activity (10 kV).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Nonimmune hydrops caused by massive fetomaternal hemorrhage and treated by intravascular transfusion.

Fetal hydrops at 26 weeks' gestation was diagnosed following a massive fetomaternal hemorrhage. Fetal intravascular transfusion was performed, and the hydrops completely resolved within 72 hours. The fetus required one more transfusion at 27 weeks' gestation. A subsequent percutaneous umbilical blood sampling at 30 weeks' gestation demonstrated a normal fetal hematocrit. A vaginal delivery at term resulted in a normal newborn. Massive fetomaternal hemorrhage is a well-known cause of nonimmune hydrops and may occur spontaneously in an otherwise normal pregnancy. Confirmation by percutaneous umbilical blood sampling and treatment by intravascular transfusion is recommended when massive fetomaternal hemorrhage causes hydrops in preterm gestations.

Adult↗
PubMedDate not supplied

Comparison between bacteriophage typing and serotyping for the differentiation of Bacillus sphaericus strains.

Eleven bacteriophages were isolated using mosquito pathogenic strains of B. sphaericus as hosts. The phage morphology and host range on five DNA homology groups including 16 mosquito pathogenic and 32 non-pathogenic strains were determined. the same bacterial strains were studied serologically for their flagellar agglutination by antisera representing eight serotypes: six antisera prepared against the reference strains for the DNA homology groups and two others against selected mosquito pathogenic strains. Two new serotypes have been determined among the non-pathogenic strains. Both phage typing and serotyping identified subgroups within the IIA homology group which contains the mosquito pathogens. The same bacterial strains were found in the subgroups established by both methods. These subgroups often paralleled difference in the level of toxicity of the strains for mosquito larvae.

Bacillus↗