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Biomedical subjects

C M Mistretta

Publications and source records attributed to C M Mistretta.

48 records · Page 3Linked to original sources
PubMed1973

Swallowing in fetal sheep.

Swallowing was measured in fetal sheep by using electromagnetic flowmeter heads chronically implanted in the fetal esophagus. The fetus swallows 20 to 200 milliliters of amniotic fluid in two to seven discrete episodes per day. The episodes are 1 to 9 minutes in duration and occur at seemingly random intervals. Swallowing is influenced by the condition of the fetus and may be the first manifestation of eating and drinking behavior.

Amniotic Fluid↗
PubMed1973

The gustatory sense in foetal sheep during the last third of gestation.

1. Histological studies revealed that presumptive taste buds are present in the foetal sheep tongue at 50 days. By 100 days the taste buds appear morphologically mature.2. To determine if foetal taste buds are functional, electrophysiological recordings were made of activity in the chorda tympani nerve of sheep foetuses. Single and multi-fibre preparations were studied in foetuses aged 100 days to term.3. Responses were recorded to lingual stimulation with salts, acids, glycerol, glycine, sodium saccharin, quinine HCl and amniotic fluid. Responses of the foetal chorda tympani to lingual stimulation with a series of monochloride salts and with increasing concentrations of one salt were similar to responses recorded in lambs and adults.4. The peripheral gustatory system of the foetal sheep is functional for at least the last third of gestation. Foetal taste experiences may influence the formation of adult taste preferences or may aid the foetus in monitoring its environment.

Acetates↗
PubMedDate not supplied

Measurement of coronary blood flow and flow reserve using magnetic resonance imaging.

PURPOSE: It was the purpose of this study to demonstrate the feasibility of performing coronary artery flow and coronary flow reserve (CFR) measurements in normal human volunteers using a magnetic resonance (MR) phase contrast technique. MATERIALS AND METHODS: Coronary flow rate, flow velocity, peak flow and CFR were determined at rest and during pharmacologically induced hyperemia in 10 healthy volunteers. The flow measurements were obtained during a single breath-hold by using a fast, prospectively gated, segmented k-space gradient-echo phase contrast acquisition with view sharing (FASTCARD PC) that was modified to improve sampling of the diastolic flow. Data were processed using the standard phase difference (PD) processing techniques as well as a new complex difference (CD) flow measurement method intended to improve the accuracy of flow measurements in small vessels. RESULTS: Mean hyperemic flow velocity (40 +/- 16 cm/s) and blood flow (3.9 +/- 1.5 ml/s) rates differed significantly from resting velocity (13 +/- 6.6 cm/s) and flow (1.1 +/- 0.4 ml/s) measurements (p < 0.0001). PD methods consistently measured larger flow rates at rest (24% larger, p < 0.0005) and stress (29% larger, p < 0.0001). CFR, calculated as the ratio of the mean PD flows (4.7 +/- 2.8), was higher than CFR calculated as the ratio of mean CD flows (4.2 +/- 1.8); however, the differences did not reach statistical significance (p = 0.07). Flow measurements performed in adjacent slices of the same vessel correlated well (r = 0.88). CONCLUSIONS: Coronary flow and CFR measurements using the MR techniques are feasible and are similar to those reported in the literature for healthy volunteers.

Adult↗
PubMedDate not supplied

Light touch thresholds in diabetic patients.

To determine whether touch acuity is altered in individuals with maturity-onset diabetes, tactile thresholds on the pad of the index finger of 32 diabetic and 27 nondiabetic subjects were compared. A set of modified Von Frey hairs was used to present touch stimuli in a forced-choice tracking procedure that controls for subject response bias. The mean tactile threshold of diabetic patients was significantly higher than that of nondiabetic subjects, although the difference between the two groups is small. Within the diabetic group, decreased tactile acuity was associated with a longer duration of disease diagnosis, presence of insulin therapy, and low-digit temperature. However, reported presence or absence of peripheral sensory symptoms (tingling, numbness, etc.) in diabetic patients did not relate to touch thresholds. The small but significant increase in touch threshold that was observed in diabetic individuals may provide an early indication of sensory neuropathy. Further use of threshold determinations will contribute to our understanding of sensory changes that accompany diabetes.

Adult↗