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Biomedical subjects

R J Brenner

Publications and source records attributed to R J Brenner.

86 records · Page 5Linked to original sources
PubMed1981

Intestinal threshold of an enzootic strain of Venezuelan encephalitis virus in Culex (Melanoconion) taeniopus mosquitoes and its implications to vector competency and vertebrate amplifying hosts.

The minimal intestinal dose of an enzootic strain of Venezuelan encephalitis (VE) virus for Culex (Melanoconion) taeniopus mosquitoes caught at a marsh habitat of VE virus in Guatemala was less than five plaque forming units (pfu) of virus. Ingestion of this dose of virus in blood of viremic hamsters resulted in transmission of virus to other hamsters. This low intestinal threshold of an enzootic strain of VE virus indicates that the natural Guatemalan population of Cu. (Mel.) taeniopus can acquire VE virus from vertebrates that have viremia levels as low as 1,000-5,000 pfu/ml of blood, provided other factors do not limit virus interchange between mosquitoes and vertebrates.

Animals↗
PubMed1981

Complete generation rearing of Simulium damnosum s.l. (Diptera: Simuliidae) in the laboratory.

A closed system of water circulation previously devised for rearing nearctic black flies was used for two cohorts of Simulium damnosum s.l. (Ghana strain). Complete generation development from field-collected eggs occurred in both instances with the production of F1 adults and F1 pupae respectively. Survival of larvae form the 3rd instar to pupation was extremely high for both parental and filial generations and ranged form 63-98%. In 3 of the 4 rearings (1P, 2P, 1F1), pupal survival ranged form 98-100%. Mating attempts were frequently seen but insemination rates were low (greater than 1%). Nulliparous females were anthropophilic and exhibited bloodfeeding rates ranging form 67.5-87.5%. Parous females also readily engorged on humans. Porcine and rabbit hosts proved less attractive while two membrane systems (Baudruche, chicken skin)using equine, bovine, or chicken blood elicited practically no engorgement. Gravid females readily deposited fertile and infertile eggs in an oviposition chamber designed originally for Simulium decorum.

Animals↗
PubMed1980

Laboratory colonization and life table statistics for geographic strains of Simulium decorum (Diptera: Simuliidae).

Colonization techniques were developed in order to select mating strains from four geographic populations of Simulium decorum. Although mating strains were established from each locale, emphasis was shifted toward developing permanent colonies from Dryden Lake, New York, USA and Warm Springs, Georgia, USA. The net reproductive rate (Ro) was computed for the parental, F1, and F2 generations of each strain in order to assess the effects of colonization through successive generations. Ro increased rapidly for both strains from parental (range of 0.34-3.5) through F2 generations (range of 16.2-21.6). Analysis of Ro components indicated that the increases in Ro were the result of two parameters that reflect the propensity of flies to mate in confinement, suggesting that selection for mating is rapid. Multiple regression analysis indicated no significant differences between strains or generations when tested against fecundity (range of 391-519) and survival of immatures (range of 90.3-97.2%). A slight positive correlation (regression coefficient of 0.0016, P less than .01) was observed between larval density (range of 284-4,439 larvae per rearing) and survival of immatures, suggesting that the limits of the rearing system with regard to crowding were not approached. Both strains readily adapt to the laboratory and are currently in the fifth generation.

Animals↗
PubMed1980

Rearing black flies (Diptera: Simuliidae) in a closed system of water circulation.

A method of rearing large numbers of black flies has been devised using a closed system of water circulation. The subsystems used for hatching, feeding, filtration, and adult trapping are labor-efficient and sufficiently flexible to be useful for rearing most species of temperate and tropical black flies. The filtration subsystem permits a daily assessment of such parameters as larval growth rate, drift, and mortality so that life table statistics can be derived for populations of immatures. Four species of black flies, Simulium pictipes, S. vittatum, S. decorum, and Cnephia dacotensis, were used in developing this unique rearing system. Percentage survival varied with species and appeared to be a function of food quantity within discrete particle-size intervals. Over 28,000 larvae of C. dacotensis were reared in a single unit with 89.3% surviving to the adult stage. In each of two rearings of S. pictipes, conducted under different nutritional regimens, approximately 60% survived to the imaginal stage. Over 9,500 adults of S. vittatum were reared from 12,127 eggs. An F1 generation of S. decorum was produced from parental stock that originated as field-collected larvae. Combined survivorship of this species approached 94% with the production of 5,847 adults.

Animals↗
PubMed1979

Scintigraphic features of nonosteogenic fibroma.

Three cases of nonosteogenic fibroma or fibrous cortical defect are presented which demonstrated scintigraphic findings of minimal to mild increased uptake of bone-seeking radiopharmaceutical and thus helped to distinguish these lesions from other benign or malignant abnormalities. The authors suggest that the two types of lesion are not fundamentally different from one another.

Adolescent↗
PubMed1979

Arteria magna revisited.

Arteria magna has been described pathologically in the literature as a peculiar and unique form of atherosclerosis. The authors offer an alternative hypothesis, based on results of angiographic studies with pathologic correlation in 18 patients with arteria magna. The findings indicate that this vascular entity might be more accurately described as a loss of the medial elastica with subsequent vessel enlargement both in length and diameter.

Adult↗
PubMed1979

Iodine absorption from the gastrointestinal tract during hypaque-enema examination.

Iodinated contrast agents administered intravenously or intra-arterially may cause serious reactions in hypersensitive patients. Oral administration of Hypaque (diatrizoate sodium) results in minimal absorption of iodine, but the amount of iodine absorbed with Hypaque-enema studies is unreported. Hypaque-enema examinations were performed in 20 normal, nonsensitive patients and increased serum iodine levels ten to 200 times base-line values, peaking after approximately one hour in patients who had measurements obtained for four hours. Therefore, before Hypague-enema studies, patients must be carefully questioned about their tolerance of iodinated contrast agents, and preparations should be made for possible serious hypersensitivity reactions.

Adult↗
PubMedDate not supplied

Ex vivo evaluation of ferromagnetism, heating, and artifacts of breast tissue expanders exposed to a 1.5-T MR system.

Three breast tissue expanders were evaluated for compatibility with MR imaging (1.5 Tesla). The metallic components of the breast tissue expanders were shown to be nonferromagnetic, heating < or = .2 degrees C and the artifacts varied. These results indicate that MR procedures may be performed safely in patients with these implants; however, artifacts may obscure implant leaks or breast lesions if located near and metal portion of the breast tissue expanders.

Artifacts↗
PubMedDate not supplied

Detection of primary breast cancer in women with known adenocarcinoma metastatic to the axilla: use of MRI after negative clinical and mammographic examination.

The purpose of this study was to evaluate the ability of MRI to identify a primary site of malignancy in the breast of patients who present clinically with ipsilateral lymph nodes containing metastatic carcinoma but whose physical and mammographic examination are negative. MRI of the breast was performed on four patients using a variety of imaging parameters, all with and without gadolinium contrast. All patients had biopsy-proven adenocarcinoma of the ipsilateral axilla, with negative physical and mammographic examinations. Foci of enhancement assessed visually on precontrast and postcontrast scans (n = 1) and on subtraction studies (n = 3) were considered suspicious under the clinical circumstances defined for this study. Lesions identified on MRI were re-identified on ultrasound examination and either preoperative localization for excisional biopsy or tissue sampling was performed. Surgery was performed and histopathologic correlation was obtained in all cases. Primary sites of breast carcinoma were identified in all four patients, with multiple sites of malignancy identified in three of four patients. Breast conservation therapy was made possible for three of four patients based on the results of the MRI study showing sites of malignancy and no features of cancer elsewhere in the breast. Follow-up data of 1, 2, and 5 years of these patients show no evidence of recurrent disease. MRI of the breast is a useful technique for identifying primary sites of malignancy in patients presenting with ipsilateral lymph nodes positive for metastatic adenocarcinoma when the physical and mammographic examinations are negative.

Adenocarcinoma↗