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Biomedical subjects

W E Collins

Publications and source records attributed to W E Collins.

At least 289 records · Page 16Linked to original sources
PubMed1978

Spatial disorientation in general aviation accidents.

Spatial disorientation (SD) was the third highest "cause" of fatal accidents in small, fixed-wing aircraft and closely related to the second highest "cause"--"continued VFR flight into adverse weather." SD was a cause or factor in 16% of all fatal accidents. When SD was ascribed as a cause or factor in an accident, 90% of the time that accident involved fatalities. Small, fixed-wing aircraft under 12,500 lb (570 kg) accounted for 97.3% of all SD accidents. Inclement weather was associated with 42% of all fatal accidents, and SD was a cause or factor in 35.6% of these. Flight was initiated into and continued into adverse weather in 19.7 and 68.7%, respectively, of SD weather-related fatal accidents. Fog (56.8%) and rain (41.8%) were the most prevalent adverse weather conditions. These and other data attest to the importance of this psychophysiological phenomenon in flight safety.

Accidents, Aviation↗
PubMed1978

Studies on the Burma (Thau.) strain of Plasmodium falciparum in Aotus trivirgatus monkeys.

The Burma (Thau.) strain of Plasmodium falciparum was established in 3 Aotus trivirgatus monkeys by the inoculation of parasitized blood from man. Subsequently, passage from monkey to monkey was obtained through subinoculation of blood parasites to 15 Aotus monkeys. Anopheles freeborni mosquitoes were fed on these infections on 207 occasions; in 105 of these trials, mosquitoes became infected. A total of 335 (9.9%) of the 3,378 individual mosquitoes dissected were infected. Passage of the infection by the bites of infected A. freeborni was attempted on 7 occasions; 4 of these transmission attempts were successful with prepatent periods ranging from 19 to 69 days.

Animals↗
PubMed1977

The seroepidemiology of malaria in Middle America. IV. Passage of malaria antibodies from mothers to infants.

In an area of El Salvador moderately endemic for malaria, use of the indirect fluorescent antibody test (IFA) showed that 44% of the infants born to mothers who had IFA responses to Plasmodium vivax of 1:20 or higher during the latter part of their pregnancy had positive IFA responses of 1:10 or higher to this antigen. No serum from an infant was positive in the absence of some level of malarial response in the mother.

Antibodies↗
PubMed1977

Attempts to immunize monkeys against Plasmodium knowlesi by using heat-stable, serum-soluble antigens.

Thirty-six Macaca mulatta monkeys were immunized with different concentrations and regimens of heat-stable, serum-soluble (S-) antigens of Plasmodium knowlesi prior to challenge with the homologous parasite via sporozoite inoculation. Fewer deaths and reduced maximum parasitemias occurred in those animals inoculated with 10 to 40 mg of S-antigen compared to nonimmunized monkeys or those receiving only Freund's adjuvant. Protection was incomplete, however, suggesting that atibodies to S-antigens may have a limited role in protection of hosts to malarial infection.

Animals↗
PubMed1977

Morphologic variants of Anopheles albimanus and susceptibility to Plasmodium vivax and P. falciparum.

Three morphologically different, true-breeding phenotypes have been isolated from a strain of Anopheles albimanus from Lake Apastepeque, El Salvador. Studies with coindigenous strains of Plasmodium vivax and P. falciparum show that these phenotypes differ significantly in their susceptibility to malaria parasites. This difference is apparent both in the number of mosquitoes that become infected and the level of infection obtained. Variations in malaria susceptibility are markedly greater with P. vivax than with P. falciparum. The significance of genetic variants within a local vector population with respect to the epidemiology of malaria is discussed.

Animals↗
PubMed1977

Studies on the Santa Lucia (El Salvador) strain of Plasmodium falciparum in Aotus trivirgatus monkeys.

The Santa Lucia strain of Plasmodium falciparum was isolated from El Salvador, Central America, and established in Aotus trivirgatus monkeys. Transmission from monkey to monkey via the bites of infected Anopheles freeborni, A. maculatus, and A, albimanus mosquitoes was obtained in 20 of 27 attempts. Prepatent periods in the monkeys ranged from 17 to 46 days with a mean of 24.3 days. Parasitemias and mortality were higher following sporozoite inoculation into animals which had been previously infected with P. vivax than in those with no previous malaria experience. Monkeys previously infected with P. vivax and P. cynomolgi had lower maximum parasitemias than those previously infected with P. vivax only.

Animals↗
PubMed1977

Infectivity of the Santa Lucia (El Salvador) strain of Plasmodium falciparum to different anophelines.

Anopheles freeborni mosquitoes were much more heavily infected with the Santa Lucia strain of Plasmodium falciparum from coastal El Salvador than were any of the other species tested. Of 5 strains of A. albimanus examined, the most heavily infected was the CA-109A and the least was the Melara, both of which come from coastal El Salvador. Of the exotic anophelines, the A. maculatus was infected at a slightly higher level than was the A. balabacensis. The incidence of highly infected individual mosquitoes was greatest in the Panama-Escobal strain of A. albimanus from the Republic of Panama; the incidence was lowest in the Melara strain from El Salvador. All strains of A. albimanus developed infected salivary glands, but the A. freeborni and A. maculatus mosquitoes appeared to develop infected glands more effeciently. Infection rates in A. freeborni mosquitoes were highest if mosquitoes were fed on Aotus trivirgatus monkeys between the 19th and 25th days of patent gametocytemia.

Animals↗
PubMed1977

The exoerythrocytic stages of Plasmodium fragile in Macaca mulatta monkeys.

Exoerythrocytic (EE) schizonts of Plasmodium fragile were found in liver tissue acquired 7, 8, 9, and 10 days following inoculation of Macaca mulatta monkeys with sporozoites from Anopheles balabacensis balabacensis mosquitoes. There was little to distinguish the EE bodies of P. fragile from EE bodies of many of the other species of primate malaria.

Animals↗
PubMed1977

Motion sickness susceptibility and related behavioral characteristics in men and women.

The incidence of motion sickness in a large (N = 3,618) college population was determined by means of a questionnaire. The test-retest reliability coefficient (0.84) suggested that the motion sickness questionnaire (MSQ) for this particular population yields highly consistent information. Significantly greater proportions of men than women had low susceptibility scores and, conversely, significantly greater proportions of women had high susceptibility scores. The relationships between motion sickness susceptibility scores and several behavioral characteristics in men and women were also investigated. Specifically, comparisons of MSQ scores were made with other self-assessments, age changes, motion experiences, familial susceptibility, use of motion sickness medication, muscular coordination, willingness to participate in motion experiments, flying experience, phobias, visual motion effects, and use of alcohol.

Adolescent↗
PubMed1977

Some psychological correlates of motion sickness susceptibility.

Four groups of 37 subjects each (highly susceptible men, highly susceptible women, nonsusceptible men, and nonsusceptible women) were obtained from a population of 2,432 college students ranging in age from 18 to 39 years. Susceptibility to motion sickness was determined by scores on a motion sickness questionnaire (MSQ); only individuals with extreme scores were considered for inclusion in the experimental groups. The following tests were administered: Floor Ataxia Test Battery, State-Trait Anxiety Inventory, Menstrual Distress Questionnaire, Cornell Medical Index, Cornell Work Form, Eysenck Personality Inventory, Rotter Internal-External Locus of Control Scale, and the 16 Personality Factors test. Each subject was tested on at least three, but not more than six, of the eight tests. Significant sex differences were obtained on the ataxia battery and the Cornell Medical Index. Susceptible subjects did not differ significantly from nonsusceptibles on the ataxia battery but did differ significantly on all personality tests except the Menstrual Distress Questionnaire (administered only to women) and the Rotter Scale. The generally consistent and significant patterns of results from the psychological tests probably reflect the selection factors used in defining the subject groups; certain personality characteristics are associated with a high degree of susceptibility to motion sickness.

Adolescent↗
PubMed1976

The seroepidemiology of malaria in Middle America. III. Serologic assessment of localized Plasmodium falciparum epidemics.

Epidemiologic studies were done in two localities, one in Panama and one in El Salvador, where outbreaks of Plasmodium falciparum malaria occurred. The indirect fluorescent antibody (IFA) method was helpful in defining the intensity of the outbreaks, the species of parasite involved, and, through parallel surveys of adjacent localities, the localized character of outbreaks. In Escobal, Panama 71 (34%) of 211 persons examined were IFA-positive for P. falciparum, although only 1 positive blood film was seen in this survey. In Jocomontique, El Salvador, 15 (28%) of 53 persons examined were IFA-positive for P. falciparum; 6 persons were parasite-positive. In the Panama study a number of children with positive IFA titers at the time of the epidemic had reverted to negative 6 months later. This lability of titers, in children, probably resulting from very early treatment of their first infection and, thus, a very brief exposure to the parasite antigen, suggests the need for caution in interpreting such negative serologic findings. Serologic studies provide valuable information in malaria epidemics, but must be interpreted in association with other known epidemiologic factors in the area concerned.

Adolescent↗
PubMed1976

Development of different strains of Plasmodium vivax in two species of Anopheles.

Anopheles freeborni mosquitoes with oocyst infections had salivary gland infections at a higher rate of Plasmodium vivax from the New World than with strains from Asia, particularly those from South Vietnam. Anopheles maculatus mosquitoes supported development from oocysts to heavily infected salivary glands for all the strains of P. vivax tested. The results suggest that P. vivax introduced from Vietnam would be less likely to be transmitted by native A. freeborni mosiquitoes than would malaria from some other areas.

Animals↗
PubMed1976

An evaluation of malaria fluorescent antibody patterns in several remote island populations of the New Hebrides, Solomons, Western Carolines, and New Guinea.

From a representative sampling of several remote populations living on the Banks and Torres Islands (New Hebrides), the Eastern and Southern Districts of the Solomon Islands, the Western Caroline Islands (U.S. Pacific Trust Territory), West New Guinea (Indonesia), and Papua New Guinea, 752 sera were examined for fluorescent antibodies to the four species of human malaria, and the results were compared to already published parasite survey data based on blood smears and medical examinations. Antibody prevalence data confirmed the presence of significant endemic malaria among most of the visited islands in the New Hebrides, and a variable but smaller amount of malaria in the Solomons. On those islands known to be free of malarial vectors, data were compatible with importation of self-limited infection by travelling residents. Malarial infection occurred in from 40% to 100% of the New Guinea villages that were visited, and was entirely absent from the Western Caroline Islands. The actual proportions of malarial species in endemic areas were not accurately reflected by relative antibody titer levels to the different species, possibly due to unpredictably high heterologous antibody reacitons following multiple mixed infections.

Adult↗
PubMed1976

Studies on human malaria in Aotus monkey. VII. Comparative infectivity of two strains of Plasmodium vivax to to Anopheles freeborni, A. maculatus, and for strains of A. albimanus.

A strain of Plasmodium vivax from El Salvador was shown to be more infectious to the Apastepeque strain of Anopheles albimanus from El Salvador than was a strain of P. vivax from Colombia, S. A. The Apastepeque mosquito strain was also more susceptible to the Savadoran strain of P. vivax than were 2 other strains of this mosquito from El Salvador. A strain of A. albimanus from Panama was more susceptible to both of the parasite than were any of the Salvadoran strains of A. albimanus.

Animals↗
PubMed1975

Serum complement and immunity in experimental simian malaria. I. Cyclical alterations in C4 related to schizont rupture.

Previous studies indicated that the level of whole serum complement (C') falls during malaria, and that the fall in C' is linked to schizont rupture and the appearance of humoral antibody. For a more detailed study of the role of C' in malaria, levels of C4 were monitored in rhesus monkeys infected with Plasmodium coatneyi. After one to two weeks of infection, significant and abrupt declines in C4 levels occurred, and these were temporally related to the process of schizont rupture. The level of C4 began to fall within a few hours after the onset of schizont rupture and fell to values as low as 2% of prerupture levels. Over the next 24-36 hr, C4 returned to normal levels, and fell again during the next cycle of schizont rupture. In general, the decline in C4 levels was positively correlated with the onset of immune response (functional and serologic) and degree of parasitemia. This marked cyclincal depletion of C4 indicates tremendous turnover of C' in primates with malaria.

Animals↗