Biomedical subjects

L Rosen

Publications and source records attributed to L Rosen.

At least 181 records · Page 10Linked to original sources

PubMed1976

A simple technique for demonstrating transmission of dengue virus by mosquitoes without the use of vertebrate hosts.

Aedes albopictus mosquitoes infected with dengue type 2 virus transmitted virus to measured small amounts of fluid which could be titrated readily for virus content. It was found that the percentage of mosquitoes transmitting was related to the extent of salivary gland infection. It was not uncommon for mosquitoes to transmit as much as 10(4) mosquito infectious doses50 of virus and transmission of significant amounts of virus was observed even though an insect only probed the test suspension without feeding to repletion. Transmission of virus was demonstrated as early as 10 days after oral infection when mosquitoes were held at 32 degrees C.

Culicidae↗

PubMed1976

Variation among geographic strains of Aedes albopictus in susceptibility to infection with dengue viruses.

The comparative susceptibility to dengue virus infection of 13 geographic strains of Aedes albopictus was studied by feeding the mosquitoes on a virus-erythrocyte-sugar suspension. Significant variation in susceptibility for each of the four dengue serotypes was observed among the geographic strains. Mosquito strains which were more susceptible to infection with one dengue serotype also were more susceptible to the other dengue serotypes. There was a direct relationship between the amount of virus ingested and the infection rate in a given mosquito strain. A 100-fold difference in oral ID50 was noted between the most and the least susceptible strains. Crossing experiments between susceptible and resistant mosquito strains produced hybrid progeny with intermediate susceptibility. Susceptibility to infection by dengue 2 virus was decreased by selective inbreeding in one strain from 74% to 13% in two generations. Further selection, however, failed to produce a completely resistant line. It appeared that the actual "barrier" to infection was in the mosquito midgut.

Aedes↗

PubMed1976

Variation among goegraphic strains of Aedes albopictus in susceptibility to infection with chikungunya virus.

Two types of variation were observed when the susceptibility of 16 different geographic strains of Aedes albopictus to oral infection with chikungunya (CHIK) virus was studied. One was differential susceptibility to infection with the virus. The other was variation in the quantity of virus present in infected mosquitoes after a standard incubation period. Mean virus titers of infected mosquitoes of different geographic strains varied almost 1,000-fold. Attempts to develop increasingly resistant or susceptible mosquito lines through genetic selection were unsuccessful. Infection rates did not change significantly despite 3 to 6 generations of selective inbreeding. In contrast, crosses between strains of high and low CHIK susceptibility yielded hybrid mosquitoes with infection rates and mean virus titers intermediate between those of the parent colonies. These data suggest that at least one factor controlling the susceptibility of A. albopictus to CHIK infection is genetic. Two lines of A. albopictus with a marked difference in susceptibility to oral infection with dengue viruses were equally susceptible to oral infection with chikungunya virus.

Aedes↗

PubMed1976

A field trial of competitive displacement of Aedes polynesiensis by Aedes albopictus on a Pacific atoll.

Prior laboratory studies and field observations suggested that it might be possible to reduce the size of the population of, or eliminate, Aedes polynesiensis by the introduction of Aedes albopictus. The former mosquito is the principal vector of nonperiodic filariasis caused by Wuchereria bancrofti and the latter is a closely related species refractory to the development of human filariae. The practicability of such competitive displacement was studied by a field trial on a remote coral atoll where there was an established population of A. polynesiensis. Three strains of Al albopictus were liberated at separate localities on the atoll and their fate was followed for 4 years. One strain disappeared within 12 months after release and the other two disappeared within 48 months. It was not clear whether A. albopicuts failed to become established because the strains were unsuitable, the general environment was inappropriate, or A. polynesiensis was present in such numbers that A. albopictus rarely succeded in mating with its own species.

Aedes↗

PubMed1975

Evaluation of a videodensitometric method for monitoring the left ventricular contractile state.

Videodensitometry of the margins of the fluoroscopic image of the left ventricle (LV) was used to evaluate LV wall motion. Differentiation of the wall motion signal reflected the velocity of LV contraction (dv/dt) during various inotropic interventions in 6 anesthetized dogs. Alterations in dv/dt were similar to changes in simultaneously measured LV peak dP/dt and the quotient of dP/dt and developed LV pressure, two widely accepted parameters of LV contractile state.

Analog-Digital Conversion↗

PubMed1975

Failure of rubella virus to replicate in mosquitos.

Rubella virus failed to replicate in mosquitoes (Aedes albopictus and Culex fatigans) following parenteral inoculation. The virus demonstrated in mosquitoes tested immediately after inoculation but was not detected in insects sampled 7, 14 and 21 days postinoculation. This experiment provides further evidence that rubella is not an arbovirus, but does not invalidate its classification as a togavirus.

Aedes↗

PubMed1975

Pancreatitis and the battered child syndrome. Report of 2 cases with skeletal involvement.

Two cases of pancreatitis associated with the trauma of child abuse are reported. In the first case the skeletal survey was initially negative but the child later showed widespread roentgen evidence of intramedullary necrosis and periosteal new bone reaction. These lesions healed without treatment. In the second patient, the pancreatitis was accompanied by ascites and subsequently by bile peritonitis, duodenal obstruction, and a bile-filled abscess in the pancreas. This patient had skeletal fractures. The clinical problems of these 2 patients emphasize the need not only to relate pancreatitis to the battered child syndrome but also to distinguish between the bone changes due to direct trauma and those related to pancreatitis.

Abdominal Injuries↗

PubMed1975

The distribution and prevalence of group A arbovirus neutralizing antibodies among human populations in Southeast Asia and the Pacific islands.

Plaque reduction neutralization tests, using five group A arboviruses (chikungunya, Ross River, Getah, Bebaru and Sindbis), were done on sera from human populations in 44 Southeast Asia and Pacific island localities. Specificity of the plaque neutralization test was determined by examining convalescent sera from patients with known alphavirus infections. Chikungunya-specific neutralizing antibodies were demonstrated in sera of persons living in South Vietnam, Northern Malaysia, Indonesia (Kalimantan and Sulawesi), as well as Luzon, Marinduque, Cebu and Mindanao islands in the Philippines. Evidence of Ross River virus infection was found among populations living in West New Guinea and Papua New Guinea mainland, the Bismark Archipelago, Rossel Island and the Solomon Islands. There appeared to be no geographic overlap in the distribution of chikungunya and Ross River viruses, with the separation in their distribution corresponding with Weber's line in the Pacific. Sindbis neutralizing antibodies were found in 7 of 21 populations sampled, but in general the prevalence of infection was low. Four sera, from Vietnam, Malaysia and Mindanao gave monospecific reactions with Getah virus. No evidence of specific Bebaru virus infection was detected. The epidemiology of these five alphaviruses in Southeast Asia and the Pacific islands is discussed.

Adolescent↗

PubMed1974