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Biomedical subjects

J Theis

Publications and source records attributed to J Theis.

At least 19 recordsLinked to original sources

Identification of a novel strain of Borrelia hermsii in a previously undescribed northern California focus.

An epizootiologic investigation testing for the presence of tick-borne relapsing fever spirochetes in rodent and tick hosts was conducted at Eagle Lake in Lassen County, California. Six of 211 O. hermsii ticks and none of 180 rodents were polymerase chain reaction (PCR)-positive for Borrelia spirochetes. Sequencing of the PCR-amplified flagellin gene fragment suggests that the spirochetes from Eagle Lake represent a previously undescribed strain of Borrelia hermsii.

Animals↗

Detection of coccidioidal antibodies by 33-kDa spherule antigen, Coccidioides EIA, and standard serologic tests in sera from patients evaluated for coccidioidomycosis.

During a 9-month study of patients being evaluated for coccidioidomycosis, 1 or more serum samples were obtained from 138 patients with an illness suggestive of recent infection. In this group, standard immunodiffusion tests of unconcentrated sera were positive for 25; 49 additional patients had at least 1 reactive test result by newer enzyme-linked serologic tests. At least 11 of these 49 patients had coccidioidomycosis as determined by culture or subsequent standard serologic tests. Patients with coccidioidomycosis identified only by newer tests had fewer or milder clinical abnormalities than did patients in whom the disease was detected by standard tests. For 31 other patients with illness of a chronic or undetermined duration, newer tests detected only 10 more than the 18 identified by standard tests, suggesting that later in the course of illness, standard testing gains in sensitivity for coccidioidal infection.

Antibodies, Fungal↗

Serosurvey of some major zoonotic infections in children and teenagers in Bali, Indonesia.

One hundred and ninety serum samples, mainly from children and teenagers, from northeast Bali were tested for the presence of antibodies against five zoonotic agents: Brucella abortus, Coxiella burnetii, Toxoplasma gondii, Toxocara canis and Trichinella spiralis. All children were negative for brucellosis and Q fever. A high prevalence rate was found for toxocariasis (63.2%) and trichinosis (19.5%). Antibody prevalence against T. gondii was found to be rather low (3.1%). To our knowledge, this is the first evidence of toxoplasmosis, toxocariasis and trichinosis infection in humans on Bali. Eating habits and poor hygiene may explain the frequency of parasitic infestations in the children and teenagers in Bali.

Adolescent↗

The sequence specificity of homeodomain-DNA interaction.

The Drosophila developmental gene, engrailed, encodes a sequence-specific DNA binding activity. Using deletion constructs expressed as fusion proteins in E. coli, we localized this activity to the conserved homeodomain (HD). The binding site consensus, TCAATTAAAT, is found in clusters in the engrailed regulatory region. Weak binding of the En HD to one copy of a synthetic consensus is enhanced by adjacent copies. The distantly related HD encoded by fushi tarazu binds to the same sites as the En HD, but differs in its preference for related sites. Both HDs bind a second type of sequence, a repeat of TAA. The similarity in sequence specificity of En and Ftz HDs suggests that, within families of DNA binding proteins, close relatives will exhibit similar specificities. Competition among related regulatory proteins might govern which protein occupies a given binding site and consequently determine the ultimate effect of cis-acting regulatory sites.

Allosteric Regulation↗

A low-cost voltage stepper device for use in patch-clamp experiments.

A simple and inexpensive device is described which generates voltage steps or cycles of steps of defined amplitude and duration either automatically (triggered by internal or computer clock pulses) or on manual command. The device facilitates the investigation of the voltage dependence of ion channel currents in patch-clamp experiments.

Animals↗

Development of embryonic pattern in D. melanogaster as revealed by accumulation of the nuclear engrailed protein.

Engrailed is required to establish and maintain developmental compartments within each segment of the fly. To understand the role of the engrailed protein in this process, we have raised antibodies against engrailed and have visualized an engrailed protein in embryos by indirect immunofluorescence. The protein accumulates in the nucleus, supporting the notion that engrailed is a regulatory factor. The first pattern of expression is in alternating segments followed by expression in every segment, suggesting that engrailed may be responding to pair-rule segmentation gene products. Overall, engrailed protein levels peak in areas undergoing morphogenesis. Finally, the complex final form of the head and terminalia derive from earlier simple subdivision of these areas into developmental fields by engrailed.

Animals↗

Molecular cloning of engrailed: a gene involved in the development of pattern in Drosophila melanogaster.

The engrailed gene acts early in Drosophila embryogenesis and plays an essential role in the processes that establish and maintain the repeating segmental pattern. To begin molecular analysis of the role of the engrailed gene in embryonic pattern formation, we used a chromosomal walk to clone genomic sequences that encompass the locus, and have physically mapped the positions of 15 engrailed mutations. The positions of engrailed rearrangement mutations indicate that the engrailed complementation unit includes a minimum of 70 kb. The locus can be divided into two regions. Rearrangement mutations interrupting the centromere proximal 50 kb of the locus result in embryonic lethality while mutants altered in the distal 20 kb of the locus survive to show morphological abnormalities in several adult segments. It appears that long-range cis interactions play a role in the function of the engrailed gene.

Alleles↗

Effects of laser irradiation on human thrombus: demonstration of a linear dissolution-dose relation between clot length and energy density.

Because vascular thrombosis often accompanies arteriosclerotic disease in occluding blood vessels, the dissolution properties of laser irradiation were investigated and the energies needed to penetrate different lengths of thrombus were quantitated. Spectrophotometric studies show that the blood clot due to the presence of hemoglobin is well absorbed by argon laser energies, which emit blue-green wavelengths between 454 and 514 nm. Thus, laser energies transmitted directly from an argon-ion source produced vaporization and penetration of human thrombus in a linear dose-response fashion; the longer the thrombus, the greater the power intensity or time exposure necessary to penetrate the clot.

Dose-Response Relationship, Radiation↗

Tropical rat mite dermatitis. Report of six cases and review of mite infestations.

Six cases of tropical rat mite (Ornithonyssus bacoti) dermatitis are presented. The patients experienced papular urticaria, and mites were found on and identified in several of the patients. The presence of rodents in or around the home was confirmed in most cases. The role of other parasitic mites found on bats, birds, and snakes is reviewed. The importance of obtaining a history of rodent activity or exposure to other animals is emphasized when considering the cause of arthropod bites.

Adult↗