Search PubMed⌕ Search

Biomedical subjects

R J Adams

Publications and source records attributed to R J Adams.

At least 163 records · Page 9Linked to original sources
PubMed1981

Genetically determined deficiency of the third component of complement in the dog.

A genetically determined deficiency of the third component of complement (C3) has been identified in a colony of Brittany spaniels. Immunochemical methods show no detectable C3 in the serum of the affected dogs, and there is no evidence of an inhibitor of C3 in the serum. The C3 deficiency appears to be transmitted as an autosomal recessive trait.

Animals↗
PubMed1981

Intrauterine mummified fetus in a rhesus monkey (Macaca mulatta).

A case of an intrauterine mummified fetus in a Macaca mulatta is described. The condition was detected in a member of a harem breeding colony, which exhibited vaginal bleeding. The mummified fetus was surgically removed and the mother made an uneventful recovery.

Abortion, Missed↗
PubMed1980

Responses of long descending propriospinal neurons to natural and electrical types of stimuli in cat.

Long descending propriospinal (LDP) neurons (antidromically identified) having cell bodies of origin in the cervical enlargement and projecting axons at least as far as the L2 segment were studied. Extracellular recording of responses to natural and electrical stimuli was done in high-spinal cats. (1) A receptive field for natural stimuli was found for 123 LDP neurons. An additional 108 LDP cells were not activated by the natural stimuli used, but some of these fired spike potentials in response to electrical stimulation of peripheral nerves of the forelimb. There was no distinction between neurons activated and those not activated by natural stimuli on the basis of location or conduction velocity. (2) The most effective natural stimuli were mechanical manipulation of the skin (both low and high threshold), movement of joints of the paw, and pressure to the deep tissues, especially to the extensor side of the arm. These modalities of stimuli were most often excitatory, but could be inhibitory as well. (3) On the basis of modality, 4 subgroups of LDP cells were identified: those which were responsive only to mechanical-cutaneous, joint-movement, or deep-pressure stimuli, and those which responded to several of these modalities of stimuli, the multimodal group. These subgroups could not be distinguished on the basis of conduction velocity. (4) The receptive fields varied in size from small (one digit) to large (all of a forelimb). For single LDP cells they included ones with single and/or multimodal input from one or both forelimbs and various combinations of excitation and/or inhibition. However, those in the dorsal horn had only ipsilateral receptive fields, mainly of the mechanical-cutaneous type. Cells with bilateral receptive fields were mainly located medially in the ventral gray in laminae VII and VIII. (5) A comparison of the location of the subtypes of LDP cells revealed that neurons activated by mechanical-cutaneous stimuli were in laminae I and IV-VIII; whereas deep-pressure and multimodal activated neurons were almost exclusively in laminae VII and VIII. (6) LDP cells receiving input from deep-pressure receptors of the paw probably relay position or weight-bearing information about the forelimbs to the lumbosacral spinal cord. This arrangement suggests that LDP neruons function in interlimb coordination and would be active during locomotion. They probably participate also in other reflexes elicited by cutaneous and deep stimuli.

Animals↗
PubMed1980

Visna-maedi-like disease associated with an ovine retrovirus infection in a Corriedale sheep.

A visna-maedi-like disease was found in a Corriedale sheep from which a retrovirus sharing the group antigen of visna-progressive pneumonia virus was isolated from lung, brain, and spleen. Clinically, the sheep had acute neurologic signs and dyspnea. Pathologic examination showed lesions similar to both visna and maedi. In the lung, there was a patchy interstitial pneumonia with marked lymphoid hyperplasia. Changes in the central nervous system were necrotizing nonsuppurative encephalitis of the brain stem, poliomyelitis of the cervical cord, and ependymitis and subependymal gliosis of the ventricles. Histologically, the central nervous system lesions seemed to have arisen sequentially, perhaps in response to bursts of virus replication as the agent underwent possible antigenic mutation. The severe lesions in both the central nervous system and lungs suggested a virus strain with dual tropism.

Animals↗
PubMed1980

An oral disease resembling noma in six rhesus monkeys (Macaca mulatta).

Over a 19-month period, five rhesus monkeys developed oral lesions of gingival erosion and bone denudation with sequestration. One other rhesus monkey developed facial necrosis which communicated with the oral cavity. These lesions were consistent with those seen in the disease called noma (cancrum oris) in humans.

Animals↗
PubMed1979

Sanguinarine: a positive inotropic alkaloid which inhibits cardiac Na+,K+-ATPase.

In isolated, isometrically contracting left guinea pig atria, sanguinarine, a benzophenanthridine alkaloid from the papaveracea Sanguinaria canadensis, produced a concentration-dependent positive inotropic effect. Between 2.3 x 10(-6) M and 6.5 x 10(-5) M, sanguinarine increased contractility by 108% which was comparable to the maximal inotropic effect of ouabain. Within the same concentration range, sanguinarine caused inhibition of Na+,K+-ATPase isolated from guinea pig myocardium. 100% inhibition of Na+,K+,ATPase activity occurred at 1 x 10(-4) M sanguinarine. The I50 for enzyme inhibition and the ED50 for the inotropic action of sanguinarine were the same (6-6.5 x 10(-6) M) indicating that both effects may be causally related.

Alkaloids↗
PubMed1979

Cells of origin of long descending propriospinal fibers connecting the spinal enlargements in cat and monkey determined by horseradish peroxidase and electrophysiological techniques.

The cells of origin of the long descending propriospinal tract (LDPT) in the cervical enlargement were studied in cat and monkey by using the retrograde transport of horseradish peroxidase (HRP). Their distribution was confirmed electrophysiologically in cat by recording their antidromic action potentials. In cats and monkeys unilateral injections of HRP were made into the gray matter of the lumbosacral enlargement, but there was some spread to the contralateral side. In cats labeled somas were found in greatest numbers in lamina VIII and medial lamina VII, bilaterally. Labeled cells also were found bilaterally in laminae I, IV--VI, and X, but few were in IV and VI. Those in lamina V were usually in the lateral part of the lamina near the reticulated region. The cross-sectional areas of 20 neurons from each of laminae I and V--VIII were measured. Cells in lamina I were smallest and the largest were in VII and VIII. In cats with the spinal cord hemisected between the injection site and the cervical enlargement containing the somas, the bilaterality of the LDPT neurons in laminae VII and VIII was confirmed anatomically and physiologically. Contralaterally projecting neurons in laminae VIII and medial VII constituted a majority of LDPT cells in those laminae. The LDPT neurons in the dorsal horn appeared to project mainly ipsilaterally, but the number of labeled dorsal horn cells in these preparations was small. The distribution of antidromically localized cells of the LDPT was found to be in good agreement with the anatomical results. Their conduction velocity was 59 +/- 22 m/s (mean +/- s.d., n = 245). Histograms of the conduction velocity by laminae are given. In monkey the distribution of labeled somas was similar to that in the cat, except that the concentration of labeled somas in the ventral horn was more medially and dorsally located. Labeled somas were found bilaterally in laminae I, IV--VIII, and X, but more appeared to be ipsilateral to the side of the injection, especially in the dorsal horn. The bilaterality of the LDPT in the monkey was not tested with hemisections of the spinal cord. Neurons of the LDPT are ideally situated for conveying sensory information from the forelimb for eliciting reflexes in the hindlimb, as has been observed after stimulating afferents in the forelimb, and for coordinating, in general, motor functions between the two pairs of limbs.

Action Potentials↗
PubMed1979

Hereditary spinal muscular atrophy in Brittany Spaniels: clinical manifestations.

A progressive neurologic disease was identified in a family of closely related Britanny Spaniel dogs. The disease developed in dogs less than 1 year old and characteristically resulted in paraspinal and proximal pelvic limb muscular atrophy. Neurologic examination, electrodiagnostic testing, and histologic studies indicated that the disease results from motor horn cell degeneration. A colony of affected dogs was established, and breeding studies incriminated an inherited basis for the disease.

Animals↗