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Biomedical subjects

C M Suter

Publications and source records attributed to C M Suter.

27 records · Page 2Linked to original sources
PubMed1985

Effects of radiation therapy on T-lymphocyte subpopulations in patients with head and neck cancer.

Cellular immunity was assessed in 85 patients with head and neck cancer with monoclonal antibodies to lymphocyte surface antigens that identify total T cells, helper cells, and suppressor cells. The control group consisted of 22 healthy volunteers. Nine patients who had surgical procedures for benign diseases were also studied. Compared with the controls, the patients with cancer who received radiation therapy had a significant decrease in total lymphocytes, T cells, helper cells, suppressor cells, and decreased helper/suppressor cell ratio. Significant decreases in lymphocyte subpopulations were not detected in patients tested before treatment or in patients treated with surgery alone. The immune deficits observed were prolonged in duration, with some present in the patients studied up to 11 years after radiation therapy. This long-lasting immune depression may have relevance to tumor recurrences and second primaries in patients with head and neck cancer treated by radiation therapy and to attempts at increasing cure rates with adjuvant agents that improve immune reactivity.

Carcinoma, Squamous Cell↗
PubMed1984

Experimental autoimmune thyroiditis: modulation of the disease level in high and low responder mice by thymosin.

Experimental autoimmune thyroiditis (EAT) in mice is characterized by production of anti-thyroglobulin autoantibodies and lymphoid infiltration of the thyroid gland. The pathogenesis of EAT is genetically controlled, but its mechanism is not yet clear. To investigate the mode of the expression of genetic control in the development of the disease, we attempted to modulate immune responses with thymosin fraction 5 (T-5) in mice which are either high or low responders to thyroglobulin. Severe thyroid lesions in high responder mice appear 2-3 weeks after immunization, while low responders develop very mild or no lesions. High responder mice have also higher antibody titer than the low responder strain. T-5 administered in five daily injections before or simultaneously with immunization, was strongly suppressive to EAT development in the high responder strain while there was no effect on thyroiditis level in low responder mice. T-5 also decreased the severity of thyroiditis in high responder mice when injected 2-4 weeks after immunization. In low responder mice, however, the same treatment increased the thyroiditis level. The effects of late injection of T-5 were dose-dependent. In all experiments, the antibody titres were not affected by T-5 treatment. The results demonstrate the ability of T-5 to modulate development and intensity of EAT. The contrasting effects of T-5 in high and low responder mice illustrate the relationship between the effects of T-5 and host immune status prior to study, suggesting that the level of immunoregulatory cell activity may differ in these two strains.

Animals↗
PubMed1981

Mechanism of propagation of canine migrating motor complex--a reappraisal.

This study quantitatively evaluated the characteristics of the aboral propagation of the canine migrating motor complex (MMC). Five conscious dogs were implanted with extraluminal force transducers along the small intestine. After constructing a 30-cm Thirty-Vella loop of jejunum, 56 of 91 activity fronts were outside the tolerance limits for propagation from the proximal intestine to the loop established in the same dogs before operation. Similarly, 44 of 109 activity fronts were outside the tolerance limits for propagation from the loop to the distal intestine. After surgery, the propagation time from the proximal jejunum to the loop was significantly increased, and activity fronts were observed to originate in the loop and in the intestine distal to the anastomosis. Our study indicates that the hypothesis that extrinsic nerves alone control the migration of the MMC is incomplete. We suggest that the extrinsic and the intrinsic innervation of the gastrointestinal tract are both required for the precise pattern of the migration of the MMC.

Action Potentials↗
PubMed1979

Tympanometry in the evaluation of vascular lesions of the middle ear and tinnitus of vascular origin.

The occurrence of vascular perturbations in the tympanogram in association with glomus tumors has previously been noted in the literature. We have broadened the scope of this method of diagnosis in the study of 3 glomus tympanicum and 3 glomus jugulare tumors, 1 dehiscent high jugular bulb, 1 aberrant carotid artery in the middle ear and 2 cases of pulsatile tinnitus of vascular origin. Analysis of illustrative tympanograms at standard and at increased sensitivity (x 20) obtained in these cases are presented. The following factors as they relate to the mechanism of recording the vascular perturbations are presented: air pressure and/or presence of fluid in the middle ear; compliance of the tympanic membrane and ossicular chain as affected by the mass, size and degree of vascularity of the mass and presence of extraneous sounds. A new method of recording the vascular perturbations utilizing a time-base generator affixed to an X-Y plotter is described. It is the purpose of this study to demonstrate the utility of obtaining tympanograms at standard and at increased sensitivity in the evaluation of vascular middle ear lesions and tinnitus of vascular origin.

Acoustic Impedance Tests↗
PubMed1977

Nystagmus responses to water and air caloric stimulation in clinical populations.

The nystagmus responses of two groups of patients referred for electronystagraphy were compared to test for differences between air and water caloric stimulation. Responses from patients with spontaneous or positional nystagmus or who showed greater than 30% directional preponderance or excitability of labyrinth were removed from the data. The 30 degree C and 44 degree C water and the 24 degree C air produced equivalent responses. The 50 degree C air produced responses with slow component velocities greater than expected; however, the distributions of computed directional preponderance and excitability of labyrinth showed no differences between the air and water caloric stimulation.

Air↗
PubMed1976

The human frequency-following response: its behavior during continuous tone and tone burst stimulation.

The frequency following response (FFR) in humans has been elicited by continuous tones as well as tone bursts. The responses were observable over a range of frequencies extending from 70 c/sec to greater than 1.5 kc/sec. The threshold for the continuous response has a mean of about 40 dB SL and is perhaps several dB lower for the burst response. The response threshold as a function of sound pressure level (SPL) increases rapidly at frequencies below 125 c/sec and above 1 kc/sec. These thresholds are particularly sharp at the lower frequencies. Narrow-band noise that just produces subjective tone masking also masks the FFR. The latency of the FFR is about 6 msec when the tone burst intensity is 30 dB over FFR threshold. Comparison with click response latencies indicates that the onset of the FFR corresponds with early waves IV and V.

Acoustic Stimulation↗
PubMedDate not supplied

Auditory brain stem response wave V latency-intensity function and three audiologic measures of cochlear function.

The purpose of this study was to compare the sensitivity of the ABR wave V latency-intensity (L-I) function to that of Alternate Binaural Loudness Balance, Loudness Discomfort Level, and Acoustic Reflex Threshold tests in identifying sensory hearing losses. Five audiometric groups were tested by each procedure. The groups included subjects with normal hearing, and with conductive, high-frequency sensory, flat sensory, and retrocochlear hearing losses. The ability of each test to separate sensory from retrocochlear impairments was investigated. A positive discriminator for cochlear impairments was of particular interest. A combination of wave V L-I slope at lower intensities and the dB HL value that separates steep and shallow slopes of the L-I function appears to meet this objective.

Adolescent↗
PubMedDate not supplied

Bilateral deafness of vascular origin.

Two patients with reversible bilateral deafness of vascular etiology are reported. Serial audiometric studies in the first patient before and after a brainstem stroke indicated retrocochlear auditory dysfunction. The second patient showed bitemporal infarction on cranial CT scan which was subsequently confirmed postmortem.

Adult↗