Gene Expression during Survival of Escherichia coli O157:H7 in Soil and Water.

The in vitro survival of Escherichia coli O157:H7 at 15°C under two experimental conditions (sterile soil and sterile natural water) was examined. DNA microarrays of the entire set of E. coli O157:H7 genes were used to measure the genomic expression patterns after 14 days.

A faculty research and training program for undergraduates in the sciences.

Faculty enthusiasm, with actual hands-on involvement, is a critical factor in establishing student research interest and excitement in a university or college science environment. Such faculty involvement is infectious to students and therefore key to restoring United States leadership in science and technology in the next decades. Most scientists acknowledge that they were initially attracted into scientific careers through one or two notable teachers who served as role models.

Baroreflex responses to the stress of severe hemorrhage in the rat.

In two groups of anesthetized (sodium pentobarbital), mature Sprague-Dawley rats, 1) aged 2 years and weighing 300-400 grams, 2) aged 6 months weighing 200-300 grams, baroreflex-induced circulatory responses to pressor (graded doses phenylephrine) and depressor (graded doses nitroglycerine) agents were compared to those occurring during progressive hemorrhage in the same animals. Graded withdrawals of blood from the femoral artery elicited progressive hypotension accompanied by bradycardia rather than expected tachycardia. Graded doses of phenylephrine (2.

Epicardial sites for vagal mediation of sinoatrial function.

The posterior atrial fat pad (PAFP) has been described as the probable anatomic location of parasympathetic ganglia mediating sinoatrial (SAN) and atrioventricular nodal function in the mammalian heart. This contrasts with recent localizations of such control elements in the pulmonary vein fat pad (PVFP) and in fatty tissues overlying the junction of inferior vena cava-inferior left atrium (IVC-ILA), respectively. Short bursts (5-8 pulses/burst, 3 bursts/train) of electrical current (1-16 Hz, 400 ms, 1-5 mA) applied directly to the ventral right atrial epicardium via a concentric bipolar electrode (separation 0.

Gross and microscopic anatomy of the vagal innervation of the rat heart.

Intrinsic cardiac ganglia and their vagal innervation are described from gross and microscopic dissections and functional studies in the anesthetized, open-chest, adult rat. Dissecting microscope sketches of the ventral and dorsal aspects of the rat heart provide gross descriptions of the anatomical course of the vagal cardiac nerves. Histological sectioning of adipose tissue packets surrounding the terminal endings of vagal branches distributed to the roots of the great cardiac vessels (aorta, pulmonary artery, precaval veins) revealed clusters of autonomic ganglia.

Hands-on laboratory experience in teaching-learning physiology.

Reactivation of several model 5 (vacuum tube) Grass polygraphs for active hands-on laboratory experiments by small student groups, in contrast to demonstrations and pretaped illustrations of physiological principles, resulted in remarkable rejuvenation of interest and excitement for learning in premed and introductory science classes at Taylor University. Accurate and perceptive observations were performed on the students themselves, each recording his own electrocardiogram, for example, as well as direct recordings from the pithed frog, the turtle heart, the anesthetized rabbit, and noninvasive recordings from students subjects during exercise. In the latter experiment, sweat recruitment patterns were recorded initially on the lower extremities, followed by successive appearances on thigh and abdomen and with final occurrence on the upper extremities and face.

Parasympathetic postganglionic pathways to the sinoatrial node.

Vagal ganglia that innervate the canine sinoatrial node (SAN) have been localized to a fat pad overlying and surrounding the right pulmonary vein complex (PVFP). The ventral epicardial surface of the right atrium was mapped in seven dogs anesthetized with alpha-chloralose after beta-blockade (timolol) and cardiac sympathetic and parasympathetic decentralization. A small, concentric bipolar exploring electrode was used to stimulate (during the atrial refractory period and using trains of five to eight stimuli per beat) systematically in the epicardial regions between the PVFP and the SAN.