Biomedical subjects

C T Yen

Publications and source records attributed to C T Yen.

40 records · Page 3Linked to original sources

PubMed1984

DNA sequences from the adenovirus 2 genome.

The sequence of 5,839 nucleotides from the adenovirus 2 genome has been determined and includes the regions between coordinates 32-44% and 66-71%. These regions contain the coding sequences for the 52,55K polypeptide, polypeptide IIIa, penton base, and the N terminus of the 100K polypeptide. Several additional unidentified open reading frames are present, including examples which overlap identified reading frames on the complementary strand and on the same strand. In conjunction with previously published sequences and those described in the accompanying papers (Akusjärvi, G., Aleström, P., Pettersson, M., Lager, M., Jöurnvall, H., and Pettersson, U. (1984) J. Biol. Chem. 259, 13976-13979; Aleström, P., Akusjärvi, G., Lager, M., Yeh-kai, L., and Pettersson, U. (1984) J. Biol. Chem. 259, 13980-13985) a complete sequence of 35,937 nucleotide pairs can now be reconstructed for the adenovirus 2 genome.

Adenoviruses, Human↗

PubMed1984

Response properties and functional organization of neurons in midline region of medullary reticular formation of cats.

Extracellular single-unit recordings were made in the anesthetized cat from neurons within the medullary raphe nuclei and nearby reticular formation. The descending axons from some of these neurons were characterized in terms of length, conduction velocity, and location within the white matter of the spinal cord. The sensory properties were characterized following somatic, baroreceptor, visual, and auditory stimuli. The mean conduction velocities of the descending axons from neurons in the medullary raphe nuclei and in the magnocellular tegmental field (26 m/s) were significantly slower than the mean conduction velocities of units in the regions immediately dorsal to them (50 m/s). Action potentials in neurons in the medullary raphe nuclei and in the magnocellular tegmental field were evoked by anti-dromic stimulation from the dorsolateral portion of the spinal cord (30 of 43, 70%), whereas neurons located in more dorsal regions along the midline and in the reticular formation projected into the ventral columns (18 of 25, 72%). Neurons were most easily activated by a tap stimulus to the body surface. This stimulus activated 84% of the neurons tested. The receptive fields were large, often including the four limbs, back, and head. Tap-sensitive neurons were found throughout the regions investigated. Stimulation of hair receptors activated 37% of neurons tested, whereas 19% responded to a high-intensity cutaneous stimulus (pinch), 35% responded to baroreceptor stimuli, 32% responded to visual stimuli, and 33% responded to auditory stimuli. Neurons responsive to pinch were likely to respond to baroreceptor stimuli and unlikely to respond to visual stimuli. Neurons responsive to visual stimuli were likely to respond to auditory stimuli.

Afferent Pathways↗

PubMed1983

Intracellular staining of physiologically identified neurons and axons in the somatosensory thalamus of the cat.

Neurons and axons responding to somesthetic stimulation in the thalamic ventrobasal complex (VB) were characterized electrophysiologically by intracellular recording and then individually injected with horseradish peroxidase. Two types of thalamocortical relay neuron were identified, primarily on the basis of dendritic morphology and axon diameter. Types with cutaneous or deep receptive fields were found in each class. Neither type had collateral axons in VB but each gave branches to the thalamic reticular nucleus (RTN). Small putative interneurons in VB and RTN neurons with somatosensory receptive fields were also injected. The RTN neurons had profusely branched widely ramifying axons in VB and adjoining nuclei. Injected medial lemniscal axons in VB had a range of receptive field properties and conduction velocities and ended in elongated anteroposterior domains with one or more dense concentrations of terminal boutons of varying size and with varying numbers of boutons.

Animals↗

PubMed1983

Control of cardiovascular function by electrical stimulation within the medullary raphe region of the cat.

An investigation was made of the effect on cardiovascular function of electrical stimulation within the midline medullary region of the anesthetized cat. Stimuli consisted of low-intensity trains of pulses. Stimulation sites were defined histologically and in some experiments, detailed stimulus maps were obtained for the effect of electrical stimulation on mean arterial blood pressure (MABP). In other experiments, measurements were made of changes produced by electrical stimulation on heart rate, cardiac output, cardiac contractility, and total peripheral resistance. Comparisons were made between the effect of stimulation at sites on the midline and sites to 1.5 mm more lateral. At midline sites, electrical stimulation most often produced a depression of the MABP. Effective depressor sites were located preferentially in two regions along the anteroposterior axis of the brain stem. At more lateral sites, electrical stimulation elevated the MABP. At most sites, changes in MABP occurred concomitantly with changes in total peripheral resistance while cardiac output was unchanged. Sites where electrical stimulation directly altered heart rate and cardiac contractility had a different distribution within the medulla compared with sites where stimulation changed the MABP.

Animals↗