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Biomedical subjects

W E Collins

Publications and source records attributed to W E Collins.

At least 217 records · Page 12Linked to original sources
PubMed1984

Studies on the Uganda I/CDC strain of Plasmodium malariae in bolivian Aotus monkeys and various anophelines.

A strain of Plasmodium malariae (Uganda I/CDC) was isolated from an infant who had been infected via blood transfusion from a donor who had entered the United States 8 yr previously. After passage through a splenectomized chimpanzee, the parasite was studied in 29 splenectomized Aotus azarae boliviensis monkeys. Maximum parasitemias were higher in Aotus monkeys without previous Plasmodium infection than in Aotus monkeys with a history of P. vivax infection. Animals with a history of infection with both P. vivax and P. falciparum had lower maximum parasitemias than did monkeys in either of the 2 preceding groups. The highest rates of mosquito infection were most often obtained during the 10-day period just after the parasite count rose above 500/mm3 of blood. The most susceptible mosquito was Anopheles freeborni followed by An. stephensi, An. gambiae, An. dirus, and An. maculatus. Two attempts to transmit the Uganda I/CDC strain of P. malariae to other monkeys by sporozoite inoculation were unsuccessful.

Animals↗
PubMed1984

Comparison of heterologous adult Brugia malayi and homologous Onchocerca volvulus antigen in the enzyme-linked immunosorbent assay (ELISA) for Guatemalan onchocerciasis.

To determine the susceptibility of a heterologous filarial antigen for measuring Onchocerca volvulus antibodies, worms were compared using an enzyme-linked immunosorbent assay (ELISA) test. Control serum samples from helminth-free U.S. residents and from helminth-infected but filariae-free Salvadoran residents were tested and compared with serum obtained from microfilariae-positive and -negative Guatemalan residents living in an area of endemic onchocerciasis. The results showed that none of the sera from U.S. residents had positive O. volvulus ELISA titers (greater than or equal to 1:160); however, 8.51% (4/47) had positive B. malayi ELISA titers (greater than or equal to 1:640). The geometric mean titers with the B. malayi ELISA test were higher than with the O. volvulus ELISA test--in sera from 47 U.S. residents (1:219 vs. 1:49), from 108 Salvadoran residents (1:92 vs. 1:71), and from 145 microfilariae-negative (1:539 vs. 1:167) and 303 microfilariae-positive (1:1,270 vs. 1:561) Guatemalan residents. The B. malayi ELISA test exhibited slightly less sensitivity than the homologous O. volvulus ELISA test; nevertheless, a good correlation (r = 0.74) was found between the 2 test antigens, indicating that the B. malayi antigen could be used to measure O. volvulus antibodies.

Adolescent↗
PubMed1984

Infection and transmission studies with the N-3 strain of Plasmodium fieldi in the Macaca mulatta monkey.

Seven different anophelines--Anopheles freeborni, An. dirus, An. maculatus, An. atroparvus, An. stephensi, An. albimanus, and An. quadrimaculatus--were shown to be susceptible to infection with the N-3 strain of Plasmodium fieldi. Transmission was obtained via the bites of An. dirus, An. stephensi, and An. maculatus mosquitoes to Macaca mulatta monkeys. Sporozoites dissected from An. freeborni were also shown to be infectious. Anopheles dirus and An. stephensi were the most suitable mosquitoes for transmission studies. Prepatent periods in M. mulatta monkeys following sporozoite inoculation ranged from 9 to 18 days with a mean of 12.3 days. Maximum parasitemias in intact animals following sporozoite inoculation ranged from 5,460 to 32,800 per mm3. Mean maximum parasitemia in splenectomized monkeys inoculated with parasitized blood was 146,000 per mm3.

Animals↗
PubMed1983

Multidisciplinary survey of erectile impotence.

A study was done of 220 men referred principally by family physicians to a multidisciplinary erectile dysfunction study group to determine the factors causing or contributing to impotence that had persisted for more than 2 months and for which no cause was apparent. The men were aged 21 to 79 (mean 50.3) years, and the duration of impotence was a few months to 15 years (mean 2.65 years). The men were to be assessed from general medical, endocrinologic/metabolic, psychiatric and urogenital viewpoints. The significance of the causal or contributory factors detected was scored by application of defined criteria and a four-point scale. The degree of loss of potency and of libido as well as level of concern were also scored by each specialist. Impotence was complete in 60%, and an associated decline in libido was reported by 38%. The level of concern was high--that is, normal--in 81% and slightly reduced in 9%. Full investigation by all the specialists was precluded by the severity of other conditions in 16 patients, by the return of potency following relief of anxiety/depression or genitourinary tract infection in 16 and for logistic or other reasons in 34. Although the cause of the impotence could be attributed in 186 of the patients, only 154 were fully assessed. Among these patients general medical factors were contributory in 46%, endocrinologic/metabolic factors in 44%, psychogenic factors (primary or secondary) in 60% and urogenital factors in 49%. Multiple contributing factors were identified in 65%, which underscores the importance of a multidisciplinary approach to assessing many cases of impotence.

Adult↗
PubMed1983

Erectile impotence: a clinical challenge.

The wide range of factors that may contribute to impotence is reviewed in an attempt to establish a systematized approach for assessing etiologic factors. The effects on potency of ageing, general fitness, weight, debilitating disease, use of therapeutic and other drugsincluding alcohol and neurogenic, vasculogenic, endocrine/metabolic, urogenital and psychogenic factors are considered and discussed. The review also affords a rationale for the methodology employed.

Aging↗
PubMed1983

The in vitro cultivation of Plasmodium gonderi.

Plasmodium gonderi, one of the vivax-type simian parasites, has been cultured in vitro by the candle jar method and by the sealed flask method. It showed a 48-hour asexual cycle and maintained its morphologic integrity. The effect of different sera (human, rabbit, and horse) was tested in culture and compared with results using rhesus serum. Growth was lower in rabbit and horse serum, but higher in human serum. Compared with individual human and rhesus serum, the multiplication rate in combined rhesus and human sera (1:1) was greater. In addition, human erythrocytes proved refractory to invasion by P. gonderi in vitro.

Methods↗
PubMed1983

Plasmodium inui and Babesia microti infections in the squirrel monkey, Saimiri sciureus.

The course of Plasmodium inui and Babesia microti infections was studied in seven splenectomized squirrel monkeys (Saimiri sciureus) of Guyanan or Bolivian origin. Three of the monkeys were infected with P. inui either by the inoculations of parasitized blood or by the bite of infected mosquitoes. The remaining four monkeys were infected by the inoculation of parasitized blood, containing P. inui and B. microti in three and with B. microti only in one. The infection in all seven animals was severe, terminating fatally.

Animals↗
PubMed1983

Diagnosis of Onchocerca volvulus infection in Guatemalan children.

Nodule examination, the Mazzotti test (a provocative challenge with diethylcarbamazine), and the enzyme-linked immunosorbent assay (ELISA) were compared for diagnostic efficacy in children who were born in an area endemic for onchocerciasis in Guatemala and were skin-biopsy negative for microfilaria of Onchocerca volvulus. Four groups of children under 16 years of age were formed based upon the possible combinations of nodule positivity or negativity and ELISA positivity or negativity. Only those children with a positive (greater than or equal to 1:160) ELISA titer had a positive Mazzotti test (9 of 20 tested), regardless of the presence or absence of nodules. These results suggest that the current ELISA serology is highly sensitive for low density infections, and should be considered in surveys for the incidence of new Onchocerca infections.

Adolescent↗
PubMed1983

Studies on the Indochina I/CDC strain of Plasmodium falciparum in Colombian and Bolivian Aotus monkeys and different anophelines.

The Indochina I/CDC strain of Plasmodium falciparum was isolated from a physician returning to the United States after working in the refugee camps along the Thailand-Kampuchean border. The strain was established in splenectomized Aotus monkeys from Colombia after being grown in vitro for 50 days. During the first three passages in Colombian monkeys, the parasites were not infective to Bolivian Aotus monkeys. After six intervening passages in Saimiri sciureus monkeys, the parasites produced high parasitemias in both Colombian and Bolivian Aotus, but gametocytes were no longer produced. Mosquito infections were obtained only during the first three passages in the Colombian monkeys. The most susceptible mosquito was Anopheles freeborni, followed by An. dirus, An. stephensi, An. maculatus, An. culicifacies, and, rarely, An. gambiae. Sporozoites were found in the salivary glands of the An. freeborni, An. dirus, An. stephensi, and An. maculatus.

Animals↗
PubMed1983

Urology in the Ottawa valley.

From the very first, the small community that was to become Bytown, and later Ottawa, was an intellectually active place. There were groups engaged in research into a wide range of subjects in the 19th century. These activities reflected first the priorities of the military period and then the interests not only of entrepreneurs and industry but also of national governments. No comparable intellectual ferment occurred in the fields of education or of medicine until after World War II, mainly because education and health were provincial responsibilities. Urology became a clinical surgical specialty, with its generally accepted boundaries of the urinary tract of both sexes and the male genital tract, towards the end of the 19th century. Urology appeared as a surgical specialty in the Ottawa area after World War I. Urologists played an active role in founding and developing the University of Ottawa School of Medicine.

History, 19th Century↗
PubMed1983

Studies of the Sal I strain of Plasmodium vivax in the squirrel monkey (Saimiri sciureus).

The Sal I strain of Plasmodium vivax was successfully adapted to three phenotypes of the squirrel monkey, Saimiri sciureus. Through five linear blood passages, parasitemias in excess of 200,000/mm3 blood were attained; Bolivian phenotype Saimiri appear to develop higher peak parasitemias. Sporozoites of the Sal I strain inoculated intravenously produced patent parasitemias in all five squirrel monkeys challenged, with prepatent periods ranging from 21 to 38 days. Anopheles freeborni and An. gambiae were the most susceptible of eight anopheline species fed on infected squirrel monkeys. As a model for in vivo studies of P. vivax the Sal I strain in Saimiri has great potential.

Animals↗
PubMed1983

Observations on the infectivity of two strains of Plasmodium vivax from Vietnamese refugees to Aotus monkeys and anopheline mosquitoes.

Two strains of Plasmodium vivax (NAM and ONG) were isolated from Vietnamese refugees and established in splenectomized Aotus monkeys from Colombia and Bolivia. Mosquito infections were readily obtained from animals with no prior malarial experience or with a history of infection with P. falciparum only. Those animals with previous infections with P. vivax supported only low parasitemias, and the mosquito infections were minimal. Complete development of the sporogonic cycle was obtained with all species of mosquitoes tested. The most susceptible mosquito was An. dirus. Other mosquitoes readily infected with these strains were An. culicifacies, An. maculatus, An. gambiae, An. stephensi, and the two North American species, An. freeborni and An. quadrimaculatus. Transmission from one monkey to another was obtained via the bites of infected An. dirus, An. stephensi, and An. maculatus mosquitoes.

Animals↗
PubMed1983

The seroepidemiology of malaria in Middle America. V. Antibody responses in an indicator population from an endemic area with attack phase antimalaria activities.

Serologic assessment was carried out in a sample of the population living in an area endemic for malaria in which control measures were being applied. The study area was in El Salvador, Central America, and antimalarial activities consisted of the residual application of the pesticide, propoxur, and drug distribution through a combination of active and passive case detection. Indirect fluorescent antibody (IFA) responses to Plasmodium vivax and P. falciparum antigens were determined on four occasions, at approximately 6-month intervals. The study population consisted of one resident from each of 268 widely distributed houses. Each person was treated with a curative course of chloroquine and primaquine at the beginning of the investigation. An increase in the proportion of positive IFA responses (greater than or equal to 1:20) and an increasing number of serologic conversions (i.e., from negative to positive or a 2-fold increase in titer) during the course of the 18-month study confirmed continued transmission of malaria. The presence of parasites in some individuals without associated serologic changes is discussed.

Antibodies↗
PubMed1982

Plasmodium falciparum gametocytes from culture in vitro develop to sporozoites that are infectious to primates.

Gametocytes of two strains of the human malaria parasite Plasmodium falciparum have been produced in high density by means of a continuous-flow cultivation system. The gametocytes of these two strains infected a mean of 36 percent and 71 percent, respectively, of Anopheles freeborni mosquitoes that fed on a suspension of red blood cells containing the culture gametocytes. Sporozoites harvested from the infected mosquito salivary glands were infective to the chimpanzee (Pan troglodytes) and the owl monkey (Aotus trivirgatus).

Animals↗
PubMed1982

Circumsporozoite proteins of human malaria parasites Plasmodium falciparum and Plasmodium vivax.

Monoclonal antibodies were raised against sporozoites of two species of malaria parasites, Plasmodium falciparum and Plasmodium vivax. The antibodies reacted with polypeptides (circumsporozoite proteins) that are uniformly distributed over the entire surface of sporozoites, as shown by indirect immunofluorescence and by the circumsporozoite precipitin reaction. The epitopes recognized by the monoclonal antibodies were expressed on sporozoites from different geographical isolates of the homologous species but were not detected on sporozoites of heterologous species nor on blood forms of the parasite. The monoclonal antibody to P. falciparum specifically immunoprecipitated two polypeptides of apparent 67,000 mol wt (Pf67) and 58,000 mol wt (Pf58) from extracts of [35S]methionine-labeled P. falciparum sporozoites. Similarly, the anti-P. vivax monoclonal immunoprecipitated two proteins of 51,000 mol wt (Pv51) and 45,000 mol wt (Pv45) from extracts of metabolically labeled P. vivax sporozoites. The extracts were also reacted with the serum of human volunteers successfully vaccinated with sporozoites of either P. vivax or P. falciparum. The patterns of immunoprecipitation were almost identical to those obtained with the corresponding monoclonal antibodies. The circumsporozoite proteins of P. falciparum and P. vivax play a role in immune protection. Incubation of the appropriate monoclonal antibody with viable sporozoites of the homologous species significantly reduced parasite infectivity, as determined by sporozoite neutralization assays carried out in splenectomized chimpanzees.

Animals↗
PubMed1982

Influence of passive and active vestibular stimulation on balance of young children.

60 children, 6 to 8 yr. old, with below-average scores on three balance tests were divided into four equal groups: active vestibular stimulation (Preston Vestibular Board), passive vestibular stimulation (rotating chair), and a control group for each. Vestibular groups were given 14 sessions of stimulation over a 5-wk. period. Balance scores for all groups, including controls, improved significantly on one or more of the tests. Improvement could not be related to vestibular stimulation.

Child↗
PubMed1982

Demonstration of hypnozoites in sporozoite-transmitted Plasmodium vivax infection.

Hypnozoites of two strains of the human relapsing malaria parasite, Plasmodium vivax, have been detected among maturing 7- and 10-day pre-erythrocytic schizonts in liver biopsies of chimpanzees infected by intravenous inoculation of sporozoites obtained from dissected salivary glands of heavily infected anopheline mosquitoes. As in the simian relapsing species, P. cynomolgi, the hypnozoites of P. vivax at 7 and 10 days are uninucleate forms of approximately 4-5 micrometers diameter, lying within the cytoplasm of individual hepatocytes. Their presence in this relapsing human species is added support for the hypnozoite theory of malarial relapse.

Animals↗