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Biomedical subjects

R J Nelson

Publications and source records attributed to R J Nelson.

At least 271 records · Page 15Linked to original sources
PubMed1980

Representation of the body surface in somatic koniocortex in the prosimian Galago.

Microelectrode mapping methods were used to determine the organization of somatosensory cortex in galagos, a prosimian primate. A systematic representation of the controlateral body surface was found within somatic koniocortex with an organization comparable to that of Area 3b of parietal cortex of monkeys (S-I proper) and primary somatosensory cortex (S-I) of other mammals. Limited studies of the response properties of single neurons within the representation revealed further similarities with the 3b field of monkeys. We conclude that somatic koniocortex of galagos and Area 3b of monkeys are homologous, and suggest the term S-I proper for the representation in both prosimians and monkeys. Differences in the details of S-I proper in galagos and monkeys suggest a more primitive organization in galagos.

Animals↗
PubMed1980

Anomalous origin of the left coronary artery from the pulmonary artery: a case report with remarkable improvement of myocardial function following subclavian artery-coronary artery anastomosis.

A 3 2/12-year-old boy with anomalous origin of the left coronary artery from the pulmonary artery was successfully treated by anastomosis of the left subclavian artery to the anomalous vessel. A remarkable improvement in left ventricular function and electrocardiogram has occurred postoperatively. This case report supports the postulation that chronically hypoperfused, electrically silent, and minimally contractile myocardial tissue may acquire its electrical activity and function with the establishment of adeqate coronary perfusion.

Cardiopulmonary Bypass↗
PubMed1979

Polioencephalomalacia in range cattle.

Polioencephalomalacia developed in 27 of 225 cattle grazing on 486 hectares of dry, short, grama grass pasture. Chemicals in drinking water, toxin from nitrate-utilizing ruminal bacteria, and documented poisonous plants were considered as etiologic agents. Attempts to reproduce the disease by injecting mice and dosing sheep with broth filtrate from nitrate-utilizing ruminal bacteria were not successful. Mushrooms collected from the pasture and fed to a cow did not reproduce the disease.

Animals↗
PubMed1979

Multiple representations of the body within the primary somatosensory cortex of primates.

Microelectrode mapping experiments indicate that the classical primary somatosensory cortex of monkeys consists of as many as four separate body representations rather than just one. Two complete body surface representations occupy cortical fields 3b and 1. In addition, area 2 contains an orderly representation of predominantly "deep" body tissues. Area 3a may constitute a fourth representation.

Animals↗
PubMed1979

The organization of the second somatosensory area (SmII) of the grey squirrel.

Microelectrode mapping methods were used to determine the organization of the second somatosensory representation, SmII, in grey squirrels. A systematic representation of the contralateral body surface was found in lateral parietal cortex adjoining the first somatosensory representation, SmI (Sur et al., '78a). The representation of the body in SmII was found to be much less distorted than in SmI. Under our recording conditions, almost all recording sites were activated from strictly contralateral body locations. The most important finding was that the basic orientation of the body representation in SmII is "erect" rather than "inverted." This orientation allows SmII and SmI to be adjoined along a common border representing the top of the head and face. This type of border has been called congruent (Allman and Kaas, '75; Kaas, '77), and it may have significance in the development of sensory representations.

Animals↗
PubMed1979

Uniform microporous biomaterials prepared by the Relamineform technique.

The Replamineform process provides a technique for fabricating microporous ceramic, metal and polymer biomedical implant materials. A range of pore sizes can be made in the same material, thus allowing independent study of the effect of pore size and biomaterial on incorporation of implants. This new family of biomaterials shows promise for helping to determine the optimum characteristics to enhance tissue regeneration.

Aluminum Oxide↗
PubMed1978

The representation of the body surface in somatosensory area I of the grey squirrel.

Microelectrode mapping methods were used to determine the organization of primary somatosensory cortex, SmI, in grey squirrels. A systematic representation of the contralateral body surface was found within somatic konicortex. This primary representation differs from maps of SmI in other mammals in at least two significant ways. The first way in which SmI of squirrels differs from the organization reported for other mammals is that SmI of squirrels contains a double representation of the hand and parts of the forearm. The glabrous skin of the digits is represented twice in a mirror image fashion joined at the finger tips. The hairy skin of the digits, wrist, and parts of the forearm are also represented twice, once on each side of the joined representations of the glabrous skin. A second unique feature of SmI of squirrels is that there is a small region of cortex completely surrounded by SmI that was unresponsive to light cutaneous stimuli under our recording conditions. This unresponsive zone is easily identified in brain sections by architectonic features that deviate from sensory koniocortex and approach motor cortex. A third significant finding was that the back is rostral to the belly in the representation of the trunk in SmI of squirrels. This is the reverse of the orientation reported elsewhere for SmI of mammals, but corresponds to the orientation of the trunk representation in Area 3b of owl monkeys (Kaas et al., '78; Merzenich et al., '78). This similarity supports an earlier contention that the representation of the body in Area 3b of primates is the homolog of SmI in other mammals (Merzenich et al., '78).

Abdomen↗
PubMed1976

Ligation of patent ductus arteriosus in premature infants.

Twenty-four neonates at 25-34 weeks' gestation with a weight range of 570-1530 g underwent ligation of patent ductus arteriosus (PDA). The infants had mild to severe respiratory distress syndrome at birth and later developed signs of heart failure as a result of left-to-right shunting through a PDA. Surgical closure of the PDA was performed within 2-31 days after birth. In the period before operation the heart rate was monitored constantly and the arterial blood-gases were assessed frequently. The trachea was intubated and respiration was controlled with a ventilator. Surgery was performed under controlled ventilation and no anaesthesia was used. Care was taken not to overventilate the lungs. Nine infants died. Death was associated with higher peak inspiratory ventilator pressures at the time of operation and with complications occurring during or after the operation. The most common complication was tension pneumomediastinum which appears to be related to excessive ventilator pressures during surgery.

Acidosis↗
PubMed1976

Improving the results of ligation of patent ductus arteriosus in small preterm infants.

Thirty-two consecutive preterm infants with birth weights under 1,500 grams and with respiratory distress syndrome (RDS) complicated by a patent ductus arteriosus (PDA) underwent ligation of PDA. The indications for operation were massive left-to-right shunting associated with heart failure (cardiomegaly and pulmonary edema) unresponsive to medical treatment. The clinical manifestations of heart failure were related to the severity of RDS. Infants with mild-to-moderate RDS (21) often recovered and later developed typical findings of PDA (bounding pulses, hyperactive precordium, and murmur). They are now operated upon as soon as respiratory support is required. Infants with severe RDS (11) develop cardiomegaly earlier, and retrograde aortography may show massive left-to-right shunting before the presence of a murmur. Ligation is indicated when blood-gas values deteriorate despite medical treatment. Nineteen (59 per cent) of these extremely preterm infants survived to be discharged and 16 (50 per cent) are developing normally. Three have neurologic impariment. None of the survivors has clinical respiratory disease, and their radiologic findings of bronchopulmonary dysplasia are improving.

Birth Weight↗
PubMed1975

Patent ductus arteriosus complicating the respiratory distress syndrome in preterm infants.

In 46 preterm infants with RDS the patency of the ductus arteriosus was established by single film aortography or by clinical diagnosis and confirmation at surgery. The estimated left-to-right shunt through the PDA by aortogram correlated well with the heart size and the clinical diagnosis of heart failure. In 14 infants massive cardiomegaly and heart failure with a PDA occurred before the appearance of a heart murmur. Twelve infants had severe RDS and 34 had mild or moderate RDS. Massive cardiomegaly occurred significantly earlier in infants with severe RDS. It is suggested that ductal ligation is indicated when an infant with massive cardiomegaly requires IPPV and whose aortagram shows that all of the contrast material is in the pulmonary arteries and none in the aortic arch. A heart murmur may or may not be present.

Aortography↗
PubMed1975

Blunt injuries to branches of the aortic arch.

Blunt injuries to branches of the aortic arch are not unusual and must be considered in any patient surviving deceleration or crush injury. Review of 36 case reports, including own own case, revealed 22 injuries to the innominate artery (4 with injuries to other arch branches), seven to the right subclavian, seven to the left subclavian, and eleven associated injuries to the thoracic aorta. Thirty patients (83 per cent) survived. Mediastinal widening (92 per cent) was the most frequent manifestation of vascular injury and is an indication for immediate aortography to delineate the entire thoracic aorta. Distal circulation was clinically decreased in less than 50 per cent, with symptomatic ischemia in only a few instances. Death was due to associated head injury in 3 of 6 cases. Earlier operation would have avoided exsanguination (one death) and late complications of false aneurysm or vascular insufficiency (10 patients).

Accidents, Traffic↗