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Biomedical subjects

J L Roberts

Publications and source records attributed to J L Roberts.

At least 271 records · Page 15Linked to original sources
PubMed1976

Analysis and outcome of 1063 patients trained for home hemodialysis.

Between 1967 and 1973, 12 home dialysis training centers (HDTC), under contract to the health Resource Administration, Department of Health, Education, and Welfare, reported training 1063 patients. Mean training time was 69 days; mean patient age was 40 yr with a range of 12 to 75 yr. Survival rates were 87% at one year, 74% at two years, 62% at three years, 54% at four years and 52% at five years. Male to female ratio was 3.2; there was no significant survival difference between sexes. Patients under 50 yr of age had significantly greater survival than did patients 50 yr and older. A "good" health status classification, defined by activity tolerance, signs and symptoms at the beginning of home dialysis, was associated with more favorable survival than were lower health ratings. Patients with glomerulonephritis, pyelonephritis and polycystic disease had better survival than did patients with diabetic, hypertensive and other renal disease etiologies. Although 51% of the patients lived 50 to 400 or more miles from the HDTC, their survival was not different from patients living less than 50 miles from the HDTC. Survival rates for patients with less than ten years of education were not significantly different from those with formal education as high as the university graduate level. Forty-seven percent of the patients were restored to full activity. These survival results are comparable with those reported for other modes of dialysis and transplantation and indicate that home dialysis is an acceptable form of therapy for a variety of patients.

Activities of Daily Living↗
PubMed1976

Neural control and proprioceptive load matching in reflex respiratory movements of fishes.

A brief anatomical description of topographical arrangements of respiratory neurons in the fish respiratory medulla introduces a discussion centered on neural controls of reflex breathing movements during rhythmic and ram gill ventilation, especially the role of proprioception in "load matching." Paralysis experiments show that proprioceptive signals are processed in medullary respiratory areas of the brain. Some neurons depend completely on proprioceptive input for their activity, while others "mix" proprioceptive and rhythmic information. The existence of direct proprioceptive control loops is revealed by fast compensating changes in electrical activity of respiratory muscles following mechanical interference with respiratory movements. Responses of respiratory neurons to short artificial twitches of respiratory muscles show that some neurons process proprioceptive information at higher levels of integration, often with a long latency and after effect. Other neurons react immediately to the stimulus and often show properties of elements in proprioceptive control systems in which length receptors facilitate and tension receptors inhibit motor neuron activity. Stimulus-response averaging applied to neuron activity and respiratory electromyograms, and to electrical stimuli and neurograms, leads to the conclusion that motor neurons and neurons mediating sensory signals from the respiratory muscles are situated close together in the medullary respiratory areas. Neuroanatomical studies are discussed which indicate that the sensory projection fields of some trigeminal fibers terminate adjacent to the cranial motor nuclei. These presumably project onto motor neurons forming fast disynaptic reflex arcs relaying sensory trigeminal information.

Animals↗
PubMedDate not supplied

Identification of proopiomelanocortin neurones in rat hypothalamus by in situ cDNA-mRNA hybridization.

Ardrenocorticotropic hormone (ACTH), beta-endorphin and the melanotropins (MSHs) are all derived from a single large precursor molecule, proopiomelanocortin (POMC) by individual processing through a series of co- and post-translational modifications. Although the primary site of synthesis is in the pituitary, POMC-derived peptides have been identified in various tissues, notably the brain (see refs 6, 7 for review). A major question concerning brain POMC is whether it is synthesized within the central nervous system (CNS) itself or whether it is taken up from plasma flowing in a retrograde fashion from the pituitary. POMC peptides have been detected immunohistochemically and biochemically in the medial basal hypothalamus, the amygdala and throughout the brain stem. POMC peptide-containing cell bodies have been identified only in two cell groups, however, principally in the periarcuate region of the hypothalamus and to a lesser extent in the nucleus of the tractus solitarius. These and other observations have suggested that POMC peptides are synthesized locally in the medial basal hypothalamus and reach other regions of the CNS by axonal transport. Civelli et al. identified POMC mRNAs in nucleic acid extracts of rat and bovine hypothalami by solution hybridization as well as Northern gel blot analysis, but because of the close proximity of the hypothalamus to the pituitary and the extremely low amounts of POMC mRNA being measured in the hypothalamus, the possibility of tissue contamination during dissection could not be ruled out. We report here the anatomical co-localization of POMC-related peptides and POMC-specific mRNAs to a single major cell group in the medial basal hypothalamus. The presence of POMC-specific mRNA in a POMC peptide-containing cell in the brain is strong support for POMC biosynthesis within brain tissue.

Adrenocorticotropic Hormone↗