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Biomedical subjects

R G Robinson

Publications and source records attributed to R G Robinson.

At least 307 records · Page 17Linked to original sources

Differential behavioral and biochemical effects of right and left hemispheric cerebral infarction in the rat.

Following ligation of the right middle cerebral artery, rats were hyperactive for 2 to 3 weeks whether activity was measured by running wheel revolutions or open field observations. Assays of brain catecholamines revealed 30 percent reductions of norepinephrine in the injured and uninjured cortex and locus coeruleus and a 20 percent reduction of dopamine in the substantia nigra. In contrast, rats with left middle cerebral artery ligations did not become hyperactive and did not show any significant change in catecholamines in any of the brain areas studied. Right and left hemispheric infarctions were comparable in their locations and extent of tissue damage. This lateralization of behavioral and biochemical response to cerebral infarction may be the consequence of anatomical or physiological asymmetries in the brain.

Animals↗

Reduced caloric intake following small bowel bypass surgery: a systematic study of possible causes.

Food intake, appetite and a variety of feelings were measured pre- and post-operatively in obese patients undergoing jejuno-ileal bypass surgery. Decreased food intake correlated closely with the amount of weight loss at both 4 and 30 months after surgery. Malabsorption correlated with weight loss at 4 months but not 30 months post-operatively. The cause of the decreased food intake is unknown and cannot be completely explained by either depression, nausea, malabsorption, liver disease, an attempt to avert diarrhoea, or decreased appetite.

Adult↗

Comparison of computed tomography and other imaging modalities in the evaluation of musculoskeletal tumors.

An algorithmic approach for the evaluation of musculoskeletal tumors is proposed on the basis of a prospective comparison of different imaging techniques in 50 unselected patients. Conventional radiography was superior to other techniques in predicting the nature of primary bone tumors. Computed tomography proved the most effective method for assessing the extent of musculoskeletal tumors and therefore had a significant influence on management in 66% of patients studied. CT was more informative than angiography and also provided more anatomical detail than ultrasound. Radionuclide scanning was mainly of value in detecting unsuspected skeletal metastases in patients with apparently solitary skeletal lesions.

Adolescent↗

Sudden onset of slow gastric emptying of food.

Three healthy, young adults suddenly experienced the onset of slow gastric emptying. Their symptoms began in February, 1975 in association with a brief illness consistent with a viral gastroenteritis. They complained of early satiety, nausea, and vomiting when they ate solid food and they had lost 11-25 kg in body weight in 8-12 mo. On admission, their physical examinations and laboratory studies were within normal limits. Their stomachs emptied a barium mixture normally, and fiberoptic endoscopy did not detect any abnormalities. The slowed gastric emptying of food was documented with radioisotopic gastric emptying studies. The prolonged emptying rates of 2 patients were reduced 90% with metoclopramide. In association with metoclopramide therapy, the patients were able to eat more food, and they regained 8-10 kg of body weight in 4-6 mo. Their histories raise the possibility that their initial illness may have damaged the mechanisms which control the gastric emptying of food.

Adolescent↗

The biodistribution of Br-77-labeled estrone: visualization of tissues containing increased estrogen receptors.

The biodistribution of a lipid-soluble brominated female sex hormone, Br-77-labeled estrone, has been determined in dogs and rabbits. Following i.v. or intragastric administration, Br-77-labeled estrone localized in the gallbladder bile within 20-25 min. Fifty-six percent of the injected activity was found in the bile at 90 min. Breast tissue was imaged by scintillation camera in three female dogs with postpartum breast enlargement at 24 hr following i.v. injection. Analysis of digitized images revealed 50% more counts per pixel in stimulated female breast tissue than was in surrounding tissue. Increased Br-77 activity in the breast was associated with the presence of increased concentrations of estrogen receptors.

Animals↗

Antibacterial activity of nitroxoline and sulphamethizole alone and in combination in urinary tract infections.

In vitro studies on the antibacterial activity of nitroxoline and sulphamethizole, alone and in combination, were undertaken and minimal inhibitory concentrations (MICs) determined on a range of urinary pathogens. Eighty per cent of the strains tested were sensitive to less than or equal to 16 mg/l of nitroxoline, and all strains, including Pseudomonas aeruginosa and Streptococcus faecalis, were sensitive to less than or equal to 64 mg/l of nitroxoline. No synergism could be demonstrated with sulphamethizole, but the combination was antagonistic when tested against strains of Ps. aeruginosa and Strep. faecalis. An in vivo study on 10 volunteers showed excellent urinary levels of nitroxoline and sulphamethizole after an oral dose of 160 mg of each agent, and 6-hour urinary nitroxoline levels were greater than or equal to 64 mg/l in 9 of the 10 subjects, and sulphamethizole levels were greater than or equal to 64 mg/l in all 10 subjects. Laboratory findings suggest that nitroxoline and sulphamethizole are both suitable agents for use in urinary tract infections caused by organisms sensitive to these agents, but there appears to be litte advantage in using them in combination.

Drug Combinations↗

Gentamicin-resistant gram-negative bacilli in hospital patients. Part II. In vitro aspects including susceptibility to tobramycin and amikacin.

A study of 259 clinical isolates of gentamicin-resistant Gram-negative bacili (GRNB) has revealed 99,2% crossresistance with tobramycin and 6,9% with amikacin. Resistance to all 3 drugs is transferable in vitro. Simultaneous transfer of resistance to ampicillin, carbenicillin, cephalothin, tetracycline, chloramphenicol, sulphonamides, co-trimoxazole, streptomycin and kanamycin was shown to occur, emphasizing the potential for the selection of aminoglycoside-resistant organisms by the use of many other drugs. All GRNB studied were multiresistant. While amikacin should prove useful for those infections caused by GRNB which require treatment, care should be exercised in its use, to minimize the emergence of large-scale amikacin resistance.

Amikacin↗

Bilateral internal carotid artery thrombosis after closed head injury.

A case of bilateral internal carotid artery thrombosis after blunt injury to the head in a 54 years old male is described. The literature is reviewed and comment is made on the causes. Unilateral thrombosis of the internal carotid artery after closed or blunt injury to the head and neck is well known but not common. There is only one previously recorded case of bilateral internal carotid artery thrombosis after such an injury (Yashon et al. 1964).

Carotid Artery Diseases↗

Changes in posterior hypothalamic self-stimulation following experimental cerebral infarction in the rat.

Bioplar stimulating electrodes were placed bilaterally in the posterior hypothalamus of rats following which the animals were shaped for intracranial self-stimulation (ICSS). When ICSS rates were stable for 1 wk, the right middle cerebral artery was ligated. During the 25-day postinfarction period, the rate of ICSS at specified current values was compared with preoperative rates. At 2 days after operation, there was a 33% decrease in the maximum frequency of ipsilateral ICSS. However, by 8 days after experimental stroke, there was a 16% increase in the maximal rate of ICSS above the preoperative value, and the rate returned to control levels by 20 days after surgery. The minimum current necessary to elicit the maximal rate of response also changed in a biphasic manner, i.e., the minimum required current was greater than preoperative control levels until 8 days after operation but then dropped below control level until 20 days postoperatively. There were no changes in the current or rate of response in the contralateral electrode. These results are discussed in relation to what may be the underlying neurophysiological changes causing these biphasic alterations in ICSS.

Animals↗

Lateral subluxation of the atlanto-axial joint in rheumatoid arthritis.

Involvement of the cervical spine by rheumatoid disease is common, but lateral subluxation at the atlanto-axial level has not been recorded previously. The condition is due to asymmetrical erosion of the lateral atlanto-axial facet joint, and may be complicated by collapse of the lateral mass of the axis. The condition should be suspected in patients with rheumatoid arthritis (RA) who present with occipital, auricular, and/or facial pain.

Adult↗

A second brain tumour and irradiation.

Three patients are described in whom irradiation of 2750 rad or more was used in the management of primary brain tumours, and 21 years or more later a second brain tumour of a different type occurred. One of the new tumours was a meningioma and the other two were cerebral astrocytomas. There is evidence to show that moderate doses of ionising radiations given in childhood for tinea capitis are associated with a late risk of developing a meningioma. Higher doses of radiation used for tumours in childhood are followed also by a late hazard of meningioma. There is insufficient evidence to implicate ionising radiations in the aetiology of gliomas. The oncogenic hazards of radiotherapy to the brain do not outweigh its therapeutic value in brain tumour.

Adult↗

Radionuclide imaging in herpes simplex encephalitis.

Eight patients with herpes simplex encephalitis among the 10 cases diagnosed at the University of Kansas Medical Center from 1966 to 1976 were studied with 99mTc early in their diagnostic work-up. The images were unilaterally positive in the temporal lobe area in all 8 patients. Radionuclide studies can suggest herpes simplex as the specific etiology in cases of encephalitis and can also indicate the best site for brain biopsy to confirm the diagnosis by fluorescent antibody techniques. Appropriate antiviral therapy should be instituted as soon as possible to alter the course of this destructive form of viral encephalitis.

Adolescent↗