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Biomedical subjects

H E Farris

Publications and source records attributed to H E Farris.

At least 19 recordsLinked to original sources
PubMed1997

A tympanal hearing organ in scarab beetles.

We describe the paired hearing organ of the scarab beetle Euetheola humilis. The auditory structures of the beetle are typical of other insect ears in that they have a thinned tympanic membrane backed by a tracheal airsac with associated chordotonal sensory structures. The tympanic membranes of the beetle are part of its cervical membrane and are located behind the head, where the cervix attaches dorsally and laterally to the pronotum. Each membrane is approximately 3 microns thick. The chordotonal sensory organ, which lies within the tracheal airsac, contains 3-8 scolopidia that attach by accessory cells directly to the tympanic membrane. Neurophysiological recordings from the neck connective of the beetle revealed that the auditory system is sensitive to frequencies between 20 and 80 kHz and has a minimum threshold of approximately 58 dB at 45 kHz. The neurophysiological audiogram is identical to the behavioral audiogram for a head roll, one behavioral component of the beetle's startle response elicited by ultrasound. Blocking experiments show that the membranous structures on the cervix are indeed the hearing organs. Neurophysiologically determined thresholds increased by more than 35 dB when drops of water covered the tympanic membranes and were essentially restored to the control level when the water was later removed. At least three other genera of Dynastinae scarabs have similar tympanum-like structures located in their cervical membranes. Behavioral and neurophysiological data show that the frequency tuning of species in two of these genera, Cyclocephala and Dyscinetus, is nearly identical to that of E. humilis. Our discovery represents only the second group of beetles known to respond to airborne sounds. However, the hearing organs of these scarab beetles differ in structure and placement from those of the tiger beetles, and thus they represent an independent evolution of auditory organs in the Coleoptera.

Animals↗
PubMed1996

Immunogenicity and safety of recombinant Helicobacter pylori urease in a nonhuman primate.

Groups of squirrel monkeys (Saimiri spp.), predetermined to be free of Helicobacter infections in the gastric mucosa, were immunized orally with 0.5-4.5 mg of Helicobacter pylori recombinant urease (rUrease) and 25-500 micrograms of Escherichia coli heat-labile enterotoxin (LT) adjuvant. Oral immunization with rUrease resulted in a markedly elevated serum immunoglobulin G (IgG) antibody response with peak levels at 45 days after immunization. No significant gastric inflammation or cytotoxicity was evident in rUrease immunized monkeys as determined by light and electron microscopy. Twenty-five micrograms of LT was a sufficient and safe adjuvant dosage, whereas higher dosages resulted in diarrhea and lethargy. Animals developed a serum IgG antibody response to LT that did not impede the production of anti-rUrease antibody levels. The results of this investigation indicate that rUrease is immunogenic in a nonhuman primate.

Adjuvants, Immunologic↗
PubMed1995

Ultrasound acoustic startle response in scarab beetles.

We discovered an auditory sense in a night-flying scarab beetle, Euetheola humilis, the first scarab to be shown to hear airborne sounds. In the field, beetles were captured beneath speakers broadcasting ultrasound that simulated bat echolocation pulses. Apparently, the beetles took evasive action from a potential bat predator and flew into the traps. Using another behavioral assay in laboratory studies, the beetles were sensitive to frequencies ranging from 20 to 70 kHz at levels between 60 and 70 dB SPL. One component of the behavioral response, a head roll, was graded with stimulus intensity, and the number of potentials in electromyographic recordings from muscles involved in the roll increased as stimulus intensity increased. The response latency was about 40 ms at threshold, decreasing to about 30 ms at 20 dB above threshold. The beetle's short response latency is ideally suited for predator avoidance behavior and the frequency tuning of the response suggests that it could function in evasion from insectivorous bats. The beetle's acoustic sensitivity is remarkably similar to that of other night-flying insects showing ultrasound-induced startle and it should provide these scarab beetles with a similar advance warning of predation risk.

Acoustic Stimulation↗
PubMed1977

Evidence against gastrointestinal pseudoparasitism by the land planarian, Bipalium kewense Moseley 1878.

The possibility of gastrointestinal pseudoparasitism by the free-living land planarian, Bipalium kewense, was tested by feeding and survival experiments. The intestinal tracts of three dogs were negative for B. kewense after the individual dogs were fed eight, three, and four large worms and autopsied at 12 h, 3 h, and 45 min, respectively. Survival of the worms in Warburg flasks, under N2, AT 27 C, was 2 h or less.. In Gas Pak jars (CO2 + H2) at 37 C, survival was less than 60 min. Aerobically, at 37 C, survival varied from 45 to 60 min. Attra-tion of the worms to stool material was examined by placing planaria inside square whose boundries were constructed of fecal smears. Bipalium kewense exposed to canine feces showed strong avoidance reactions. Urea, a nitrogen end product of these worms, was also shown to be a negative stimulus for B. kewense. Failure to establish even short term passage in the digestive tract, lethality of 37 C and anaerobic environments, and sensitivity to feces makes gastrointestinal pseudoparasitism unlikely in these organisms.

Anaerobiosis↗
PubMed1976

Cryosurgical treatment of ocular squamous cell carcinoma of cattle.

A total of 718 ocular squamous cell carcinomas of cattle were treated with various cryosurgical units and techniques during a 2.5-year study. In 609 of the lesions, a single freeze was used, with a cure rate (total regression) of 66%. In 109 lesions treated with a double freeze-thaw cycle (rapid freeze to - 25 C, and unaided thaw followed immediately by refreezing to -25 C), the cure rate was 97%. Cryosurgical units designed for delivery of liquid nitrogen provided a more rapid rate of freezing and, thus, a higher cure rate than did units designed for delivery of nitrogen vapor. It was concluded that cryosurgery for treatment of squamous cell carcinoma is a simple and rapid procedure; is economical; provides analgesia itself, due to sensory nerve injury; requires minimal preoperative and no postoperative medication; causes minimal side effects; may be repeated; and is excellent for use on suspect premalignant lesions.

Animals↗
PubMed1967

Classical conditioning of courting behavior in the Japanese quail, Coturnix coturnix japonica.

Male Japanese quail were classically conditioned to display courting behavior at the sound of a buzzer, a previously neutral stimulus. The buzzer (conditioned stimulus) was paired with the presentation of a female quail (unconditioned stimulus) for a number of trials. The courting display, invariably elicited from the male by the presentation of the female, began to appear in part to the conditioned stimulus as early as the fifth pairing. All components of the display were elicited from all birds by the conditioned stimulus alone within 32 pairings of the conditioned and unconditioned stimuli.

Animals↗
PubMedDate not supplied

Spontaneous diabetes mellitus in the New Zealand white rabbit: history, classification, and genetic analysis.

A colony of NZW rabbits was developed in which 18 of 126 members exhibited overt symptoms of diabetes mellitus. On the basis of total body weight measurements, obesity does not appear to play a primary role in the development or manifestation of the syndrome. The relatively high frequency of occurrence of spontaneous diabetes mellitus in this colony seems to suggest a unique genetic predisposition of these rabbits, yet analysis of glucose tolerance of colony animals indicates no clear genetic mode of transmittance of the trait. Rather, data suggest a possible interaction of as yet undefined genetic and/or environmental influences as being responsible for the disease state. Regressions of k-value on age indicate an early predetermination of glucose intolerance in the rabbits. In addition to a planned program of breeding, investigations of dietary intake and possible relationships of the diabetic condition to bacterial or viral infections appear to be initial areas indicative of further study.

Animals↗