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Biomedical subjects

D T Karzon

Publications and source records attributed to D T Karzon.

At least 55 records · Page 3Linked to original sources
PubMed1976

Clinical reactions and serologic response following inactivated monovalent influenza type B vaccine in young children and infants.

A monovalent, zonally purified, inactivated influenza B vaccine was administered to 29 children, 3 to 6 years of age, and 16 infants, 12 to 28 months of age, as a single dose of 0.25 ml containing 250 chick cell agglutinating units. The vaccine was both antigenic and well tolerated in the older group of preschool children. In the infants the vaccine was also antigenic but poorly tolerated clinically. Febrile reactions to 102 or greater were seen in 9 of the 16 infants, and two of these infants experienced a seizure following vaccination. The clinical reactions observed with the administration of influenza B vaccine in the dose used in this study would suggest significant limitations on its use in children under 3 years of age.

Antibody Formation↗
PubMed1976

Evaluation of a live, attenuated respiratory syncytial virus vaccine in infants.

Respiratory syncytial virus ts-1 is a live attenuated experimental vaccine which was administered intranasally to 25 infants 11 to 19 months of age. Clinical evaluation was carried out following a controlled, double-blind protocol which eliminated observer bias, assessed intercurrent illness, and was designed to detect virus transmission. At the low dose of virus of virus used (100 TCID50) 8 of the 25 recipients were successfully infected with RS virus ts-1 as determined by virus shedding or antibody response.

Antibodies, Viral↗
PubMed1975

Safety and antigenicity of influenza A/Hong Kong/68-ts-1 (E) (H3N2).

Influenza A/Hong Kong/68-ts-1 [E] (H3N2) vaccine was administered intranasally to 18 seronegative children 14 to 32 months of age. Fourteen children, 78%, shed influenza A/Hong Kong virus for a mean of eight days following vaccination. Sixteen children, 89%, experienced a fourfold or greater rise in hemagglutination-inhibition antibody. Some children appeared to experience a febrile reaction to the vaccine although interpretation of this data was complicated by intercurrent illness. These findings demonstrate that influenza A ts-1 [E] replicates more readily in the young seronegative child than in the HAI negative adult. In addition, the temperature-sensitive marker of the vaccine was not genetically stable in four of the vaccinated children. Careful evaluation of any future live respiratory viral vaccines needs to be undertaken in the young seronegative child before the vaccine's safety is fully established.

Administration, Intranasal↗
PubMed1972

Iguana virus, a herpes-like virus isolated from cultured cells of a lizard, Iguana iguana.

An agent cytopathic for Terrapene and Iguana cell cultures was isolated from spontaneously degenerating cell cultures prepared from a green iguana (Iguana iguana). The agent, designated iguana virus, caused a cytopathic effect (CPE) of a giant cell type, with eosinophilic inclusions commonly observed within giant cell nuclei. Incubation temperature had a marked effect on CPE and on virus release from infected cells. Within the range of 23 to 36 C, low temperatures favored CPE characterized by cytolysis and small giant cell formation, and significant virus release was observed. At warmer temperatures, a purely syncytial type of CPE and total absence of released virus were noted. A unique type of hexagonal eosinophilic cytoplasmic inclusion was observed within syncytia of infected Terrapene cell cultures incubated at 36 C. In vivo studies revealed no evidence of pathogenicity of iguana virus for suckling mice, embryonated hen's eggs, or several species of reptiles and amphibians. Inoculation of iguana virus into young iguanas consistently caused infection that was "unmasked" only when cell cultures were prepared directly from the infected animal. Filtration studies revealed a virion size of >100 nm and <220 nm. Iguana virus is ether-sensitive and, as presumptively indicated by studies of inhibition by bromodeoxyuridine, possesses a deoxyribonucleic type of nucleic acid. The virus characteristics described, as well as electron microscopy observations described in a separate report, indicate that iguana virus is a member of the herpesvirus group.

Animals↗
PubMed1971

Effect of host cell on distribution of a lysosomal enzyme during virus infection.

The time of appearance of a lysosomal enzyme, beta-glucuronidase, in the medium of cells infected with either measles virus or echovirus 6 varied with the host cell system. Replication and release of virus preceded leakage of beta-glucuronidase from green monkey kidney cells. In contrast, extracellular enzyme appeared before replication and release of virus in human amnion cells. Hydrocortisone depressed enzyme leakage but did not retard replication of measles virus or viral-induced cytopathology. The intracellular distribution of beta-glucuronidase in uninfected and measles virus-infected cells was also studied. Measles virus infection altered the position of particulate-bound beta-glucuronidase in linear sucrose gradients prior to substantial release of this enzyme intra- and extracellularly. At early stages in infection, most of the cell-associated virus banded with particulate-bound enzyme in the middle of the gradient. As infection progressed, separation of measles virus infectivity from enzyme activity occurred, and intracellular virus was recovered near the meniscus of sucrose gradients.

Amnion↗
PubMed1970

Thermoelectrically cooled temperature-gradient apparatus for comparative cell and virus temperature studies.

Establishment of a near-linear temperature gradient in an incubator has been accomplished by the application of heat to one terminus of a conducting body, normally a metal bar, and the removal of heat from the other terminus of the conducting body. Such incubators have been complex and unwieldy because of the need for mechanical refrigeration. We have described a simplified temperature gradient incubator which uses thermoelectric module cooling coupled with electric heating. Along the gradient, 20 stations in two parallel rows of 10, each accommodating a 30-ml plastic cell culture flask, were continually monitored by an electronic thermometer, and the temperatures were recorded. By manipulation of two simple potentiometer controls, any temperature gradient between 0 and 50 C could be obtained. Minor deviations which occurred between theoretically perfect and obtained temperature gradients were reproducible and readily measured. The gradient incubator was particularly applicable to (i) simultaneously studying a given biological activity over the entire temperature range supporting the growth of a given cell, virus, or microorganism, or (ii) precisely defining the upper or lower temperature limits of a biological system by 10-point determinations. Preliminary experiments have demonstrated the usefulness of the apparatus in characterizing the temperature limits for growth in vitro of cells of reptilian cell lines. The gradient incubator was also successfully utilized for the characterization of the effect of temperature on the efficiency of plating of amphibian viruses and possible temperature variants of those viruses.

Animals↗