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Biomedical subjects

J H Martin

Publications and source records attributed to J H Martin.

At least 91 records · Page 5Linked to original sources
PubMed1984

Immobilization hypercalcemia in acute spinal cord injury treated with etidronate.

Hypercalcemia developed in a 30-year-old C5 quadriplegic six months after he received a gunshot wound in the cervical spine. Short-term treatment consisted of fluids and diuretics, but conventional drug therapy for long-term maintenance of normocalcemia was not effective. A regimen of etidronate disodium was then instituted, which resulted in normocalcemia. When use of this drug was discontinued at intervals during the therapy, the hypercalcemia recurred. The patient's condition was maintained on the etidronate regimen until full mobilization occurred, at which time the drug therapy was discontinued and normocalcemia persisted. This case represents, to our knowledge, the first reported success with the use of etidronate in the treatment of hypercalcemia in the immobilized patient with acute spinal injury.

Acute Disease↗
PubMed1983

Response of neurons in primary somatosensory cortex of cat following prolonged exposure to strong sinusoidal mechanical stimuli.

Psychophysical studies in humans have demonstrated adaptation of the mechanoreceptive submodalities of flutter and vibration after prolonged presentation of a strong adapting, or conditioning, stimulus. In our studies we recorded from single neurons in cat primary somatosensory cortex, and followed a paradigm in which the response of a single unit was measured before and after the presentation of a strong conditioning stimulus. Our findings show no adaptive response in the 30 sec period immediately after cessation of the conditioning stimulus, and suggest that other parallel ascending pathways or somatosensory cortical areas other than SI account for these psychophysical observations.

Adaptation, Physiological↗
PubMed1983

Receptor anticipation of mentally retarded and nonretarded adults.

The effect of stimulus velocity and information feedback on the receptor anticipation (Poulton, 1957) performance of mentally retarded and nonretarded adults was investigated. Thirty trials were given in which subjects attempted to execute a preferred-hand button press response coincident with the lighting of the last of a series of runway lamps illuminating in a pattern of apparent linear motion. Although the receptor anticipation of nonretarded adults was found to be significantly superior to that of retarded subjects, both groups responded similarly to the velocity and feedback manipulations.

Adult↗
PubMed1982

Pulmonary blastoma: an ultrastructural study emphasizing intestinal differentiation in lung tumors.

Features of intestinal differentiation, including the presence of brush borders, have been described previously in a pulmonary blastoma following xenotransplantation in athymic nude mice. This paper reports similar findings in a pulmonary blastoma subjected directly to electron microscopic study. Ultrastructural manifestations of intestinal differentiation in other types of primary lung tumors are also discussed.

Aged↗
PubMed1982

Restriction endonuclease analysis of varicella-zoster vaccine virus and wild-type DNAs.

The DNA from several clinical isolates of varicella-zoster virus (VZV) were compared with the DNA from the vaccine strain VZV using three restriction endonucleases: BamHI, BgII, and HpaI. When electrophoresed through an agarose gel, the vaccine DNA digestion pattern was significantly different from the digestion patterns of the wild-type DNAs. Variations in the digestion pattern of the separate clinical isolates were also observed.

Bacterial Proteins↗
PubMed1982

The control of rapid limb movement in the cat. III. Agonist - antagonist coupling.

Electromyographic (EMG) activity associated with rapid voluntary limb movements exhibits a characteristic "three burst pattern". The first burst is in the agonist muscle (AG1), the second is in the antagonist (ANT) and the third is again in the agonist (AG2). The present study was undertaken to determine whether ANT and AG2 reflect preprogrammed commands or responses to stretch consequent upon limb displacement. To answer this question EMG activity of agonist and antagonist muscles was examined in cats performing a tracking task. To dissociate centrally programmed muscular events from their intended mechanical consequences, isometric and anisometric conditions were presented in either a predictable or unpredictable sequence. A torque motor was used to control limb trajectory and to impose passive angular displacements. Whereas AG1 was present under both isometric and anisometric conditions, ANT and AG2 required limb displacement and were time locked to movement parameters. ANT occurred within 15 ms following the onset of acceleration. its magnitude varied linearly with this parameter and inversely with AG1. Passive displacements stretching the antagonist elicited responses with similar latencies and greatest magnitude for a given acceleration. AG2 was only present in underdamped movements with terminal oscillations and typically occurred when the position reached its peak and the velocity recrossed zero. Its magnitude was a function of both limb deceleration and of intended force. The data indicate that both ANT and AG2 represent responses to muscles stretch whose amplitudes are modulated by descending commands. Reciprocal mechanisms operating at a spinal level could account for the reduction of the antagonist response as a function of intended force. The increased sensitivity of late stretch responses in the agonist with higher intended forces is compatible with motoneuron facilitation by tonic descending commands. It is proposed that the stretch evoked responses function to dampen terminal oscillations which ensue from rapid displacement of the mass of the limb against elastic forces of muscle and soft tissue.

Animals↗
PubMed1981

Immunogenetic control of experimental type II collagen-induced arthritis. I. Susceptibility and resistance among inbred strains of rats.

Seven inbred rat strains were tested for susceptibility to experimental type II collagen-induced arthritis and for development of cellular immunity to type II collagen by delayed hypersensitivity skin testing. WF (RT1u), LEW (RT1l), and DA (RT1a) were the most susceptible of the strains tested with respect to incidence (greater than 95%) and severity of disease. LEW and DA were strongly skin test reactive to calf type II collagen. BUF (RT1b) developed moderate skin test responses to calf type II collagen and showed low susceptibility to collagen arthritis (1/8). MAXX (RT1n), LEW.B3 (RT1nvl), and AUG (RT1c) were not susceptible to collagen arthritis and showed negative to very weak skin test responses to type II collagen. Disease susceptibility was inherited as a dominant trait in the F1 progeny of (WF X LEW.B3) matings. These data suggest that clinical expression of experimental collagen-induced arthritis and immune responsiveness to type II collagen are controlled in part by genes within or closely linked to the rat major histocompatibility complex--RT1.

Animals↗
PubMed1980

Spinal melanotic clear-cell sarcoma: a light and electron microscopic study.

We report a melanotic spindle-cell tumor that arose from a thoracic spinal nerve root and metastasized to both lungs. The bulk of the tumor consisted of glycogen-rich clear cells and bore a striking resemblance on light and electron microscopy to at least one variant of the clear-cell sarcoma of tendons and aponeuroses. The presence of schwannoma-like areas noted in the primary tumor on light microscopy and the formation of a highly developed basal lamina noted on ultrastructural examination suggest that the tumor may be a partially dedifferentiated malignant melanotic schwannoma. This tumor is discussed in the context of a simple histogenetic classification of melanotic tumors.

Adolescent↗
PubMed1980

An analysis of population growth rates within typological categories of small southern cities.

"The research reported here presents a typology of small cities, as well as an analysis of the causes of population growth within city types. For this research eighty-eight incorporated cities and towns in the South Atlantic and East South Central census divisions [of the United States] were chosen for investigation, all having 1960 populations between 10,000 and 50,000." Path models are constructed for each city class using the decennial rate of population growth between 1960 and 1970 as the endogenous variable and net migration and employment changes as intermediate variables.

Americas↗
PubMed1979

Replication of standard and defective Ross River virus in BHK cells: patterns of viral RNA and polypeptide synthesis.

Virus-specific macromolecule synthesis has been examined in BHK cells infected with Ross River virus. Unpassaged virus (R-0) and tenth-passage virus (R-10) have been compared. In infected cells R-0 generates i) 45S, 28S, 33S and 26S viral RNAs, ii) virus-specific precursor polypeptides of mol. wt. 127,000, 95,000 and 61,000 and iii) viral envelope proteins (mol. wts. 52,000 and 49,000) and nucleocapsid protein (mol. wt. 32,000). Thus in terms of virus-specific RNA and polypeptide synthesis, the replication of standard RRV is analogous to that of Semliki Forest virus and Sindbis virus. R-10 interferes with the replication of standard Ross River virus and generates large amounts of 19S and 24S defective RNA species; 45S and 26S RNA synthesis was not markedly affected. Defective RNAs are associated with RNAse-sensitive, 50S cytoplasmic particles which contain a variety of (mainly host) proteins but no nucleocapsid protein. No evidence for translation of defective RNAs was obtained. R-10 infection is also characterized by a relatively early shut down of host protein syntehsis and by a reduction in virus-specific polypeptide synthesis and nucleocapsid formation. The data suggest that defective Ross River virus interferes primarily at the translational level.

Animals↗
PubMed1979

Convoluted secretory material in thyroid follicular epithelial tumors.

Electron microscopy may occasionally be useful, when routine histopathologic methods fail, in the typing of tumors, including those that present as metastases from occult primary sites. We describe a case in which the presence of an uncommon ultrastructural feature aided in establishing the thyroid gland as the source of a skeletal metastatic tumor.

Adenocarcinoma↗
PubMed1979

Fine structure of the tegument of Mesocestoides tetrathyridia by scanning and transmission electron microscopy.

The tegumental surface of tetrathyridial stages of the tapeworm, Mesocestoides corti, was studied by scanning and transmission electron microscopy. Two structural types of microvilli were observed--blade-shaped or conical ones, and elongated, slender microvilli. The distribution and relative frequency of the two types of microvilli differs in different areas of the body surface. Host peritoneal cells were observed attached to the blade-shaped microvilli by slender cytoplasmic projections.

Animals↗