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Biomedical subjects

R L Roth

Publications and source records attributed to R L Roth.

8 recordsLinked to original sources
PubMed1989

Analysis of an incompetence case.

In recent months various Maryland health occupational boards have come under fire for their response to complaints against particular licensees. While this criticism may or may not be justified, the issue of how to proceed against incompetent licensees is a common problem nationwide. In Maryland's explosion of cases involving malpractice, far more licensees are disciplined for offenses relating to drugs or sex than for incompetence. An approach to make the boards more responsive to the problem of the incompetent licensee is presented.

Clinical Competence↗
PubMed1981

Serial exercise testing after coronary artery bypass surgery.

To determine the duration of functional benefit from coronary bypass surgery, 111 patients with angina pectoris were serially evaluated by standard exercise testing prior to and for up to 4 years after surgery. Exercise testing 6 to 18 months after surgery showed greater heart rate-blood pressure product at peak work load, improved work capacity, and less symptomatic and electrocardiographic evidence of ischemia than was demonstrated preoperatively. Twenty patients were tested 37 to 48 months postoperatively and showed improved exercise performance in comparison with preoperative results, but the frequency of positive tests during this period no longer differed. Thus, improved exercise performance appears to persist for at least 4 years after coronary bypass surgery.

Angina Pectoris↗
PubMed1980

Expulsion of Nippostrongylus brasiliensis by mice deficient in mast cells.

Expulsion of the intestinal helminth, Nippostrongylus brasiliensis, occurs spontaneously about 2 weeks after a primary infection of rats and mice. Cellular changes in the small intestine coincident with the period of expulsion have suggested several mechanisms by which this 'self-cure' may be effected. Local anaphylaxis was proposed as a possible means of parasite clearance; this hypothesis has been supported by the demonstration of specific reaginic antibody production and jejunal mast cell accumulation in infected animals. In addition, increased mucus secretion and more recently, goblet cell proliferation in the jejunal mucosa of rats have been noted and considered as potentially important in mediating the self-cure reaction. The data presented below indicate that in the absence of demonstrable mast cells, the course of a primary infection with this parasite is unchanged; however, they are supportive of a role for globlet cells in the self-cure reaction.

Animals↗
PubMed1979

Decussion geometrics in the goldfish nervous system: correlation with probability of survival.

In the goldfish, the optic nerve decussation occurs without intermingling of fibers from the two eyes. In two-thirds of juvenile and adult specimens, the left optic nerve is dorsal at the midline. In about 60% of the specimens, the decussation of Mauthner's neuron also has a left-dorsal-to-right (L/R) configuration. Concordance for decussation geometry is greater than 80%, with smaller specimens accounting for a disproportionate number of discordant cases. In embryos and very young larvae, the L/R configuration occurs in slightly less than 50% of optic chiasmata and in slightly more than 50% of Mauthner's cell chiasmata, and there is no significant tendency toward concordance. However, larval specimens that survive 1 month after hatching are markedly skewed toward adult decussation patterns and somewhat skewed toward concordance. These observations, together with results of cannibalization and predation experiments, suggest that the adult population pattern can be achieved through selection pressures against discordant individuals and, perhaps separately, against individuals with right-dorsal-to-left (R/L) chiasmatic configurations. Decussation patterns correlate with embryonic postures, larval orientation preferences, and growth rates after hatching, which may themselves serve as a basis for selection.

Age Factors↗
PubMed1975

Histological evidence for direct connections between the optic lobes of the cockroach Leucophaea maderae.

Heretofore, descriptions of direct interconnections between insect optic lobes have been based on histological examinations of normal brains or on inference from electrophysiological or behavioral data. We present here what we believe to be the first demonstration of such monosynaptic connections by techniques of experimental neuroanatomy. Twenty-four to 39 h after extirpation of the left optic lobe, degenerating axons and axon terminals, as silvered by a modified Nauta technique, were abundant in the central portion of the medulla of the right optic lobe. The periphery of the medulla was free of argyrophilic debris as were the lobula and lamina. The distribution of neuronal somata with processes terminating in the the left optic lobe was established by retrograde axonal transport of horseradish peroxidase injected into the left lobe and by the development of distinctive perinuclear rings of RNA (a 'chromatolytic' reaction) by some cells within 1-2 weeks following amputation of the left lobe. Both techniques revealed distinct clusters of cells in the anteroventral and posterior regions of the right optic lobe, and in the medial portion of the right protocerebrum. The cells which interconnect the two optic lobes may be involved not only in the bilateral representation of visual information, but also in the coordination of optic lobe pacemakers which control a circadian rhythm of locomotory activity.

Animals↗