Biomedical subjects
J Ryan
Publications and source records attributed to J Ryan.
Asymptomatic intracardiac metastasis from osteosarcoma: a case report with literature review.
Osteosarcoma very rarely metastasizes to the heart. Thirteen cases have been reported in the literature so far. Diagnosis in some of these cases was made during investigation for severe cardiac failure and in most of them at autopsy. Our patient, a 13-year-old girl, showed right pulmonary metastases on chest x-ray 1 year after above knee amputation for osteosarcoma of the distal femur. Routine preoperative computerized axial tomography (CT Scan) revealed a calcified lesion in the heart in addition to the pulmonary metastases. She was very active and completely asymptomatic. Two-dimensional echocardiography, angiography, and right and left heart catheterizations were done. This revealed a large mobile metastatic lesion in the right ventricle. The intraventricular tumor was successfully removed, and 12 days later she had a second thoracotomy for removal of pulmonary metastases. Nine months after her intraventricular metastasis was removed she developed a solitary right pulmonary metastasis. This was successfully resected. Now, 10 months later, she is disease free and completely asymptomatic.
Mouse killing in rats induced by lesions of the medial hypothalamus or medial accumbens: short-term preoperative exposure to a mouse does not suppress the killing.
Rats were either exposed or not exposed to a mouse in their living cage for a 48-hr period. At the end of this time a bilateral lesion was made in the medial accumbens region or in the medial hypothalamus. When tested 2 days postoperatively, the killing frequency among rats that had been exposed to mice preoperatively was not significantly lower than that of rats that were not preoperatively exposed. The ineffectiveness of preoperative experience in suppressing the mouse killing induced by medial accumbens and medial hypothalamic lesions is similar to that found previously with dorsal-median raphe lesions and olfactory bulb lesions and is in contrast to the ease with which preoperative experience prevents mouse killing induced by septal lesions and serotonergic lesions induced by 5,7-dihydroxytryptamine.
Chromosomal assignment of a family of human oncogenes.
A family of human transforming genes, previously shown to share homology with the ras family of viral oncogenes, maps to three different human chromosomes. A well-characterized mouse-human hybrid cell panel, combined with Southern blotting, was used in this study. The transforming gene of the T24 bladder carcinoma cell line maps to human chromosome 11. An oncogene isolated from the lung carcinoma cell line SK-Calu-1 maps to human chromosome 12. The third ras-related gene, cloned from SK-N-SH, a neuroblastoma cell line, maps to human chromosome 1.
A hypertension follow-up program.
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Hypoglycemia associated with antibodies to the insulin receptor.
Antibodies to the insulin receptor are insulinomimetic in vitro, although they generally induce insulin resistance in vivo. We report the novel case of a patient who presented with fasting hypoglycemia as the sole manifestation of autoantibodies to the insulin receptor. Prednisone therapy (120 mg per day) produced a rise in fasting glucose to more than 100 mg per deciliter (6 mmol per liter) within 48 hours, although there was no detectable change in the titer of antireceptor antibodies. After 10 weeks of therapy, the titer of antireceptor antibodies had fallen approximately 100-fold, and prednisone could be discontinued without recurrence of hypoglycemia. This case demonstrates that antireceptor antibodies must be considered in the differential diagnosis of hypoglycemia, especially in patients with other manifestations of autoimmunity.
Oxygen tension of the skin of ischemic legs.
Using a Kontron Roche Transcutaneous Oxygen Monitor, we measured oxygen tension on the skin of the legs at three sites in patients with peripheral vascular disease and group of controls. Significant decreases in oxygen tension occurred in the patient groups, which correlated well with ankle systolic pressure, with differences between those with claudication and those with rest pain. These results suggest that in limbs with claudication, significant skin hypoxia may exist during rest in spite of reportedly normal skin and muscle blood flow. The progressive decrease in skin oxygen tension down a limb with occlusive vascular disease may play a significant role in skin healing.
A comparison of the effect of preoperative gentling on the mouse killing and reactivity induced by lesions of the lateral septum, the medial accumbens nucleus, and the medial hypothalamus.
Adult male rats were either gentled or not gentled 10 min each day for 5 days and then subjected to lesions of the lateral septum, the medial accumbens, the medial hypothalamus, or were given sham lesions. Mouse killing was tested in the living cage on Days 2, 7, and 14 postoperatively while reactivity to the experimenter was tested on Days 3, 8, and 15. The frequency of killing in the gentled groups was always significantly higher than that of the gentled sham-lesion controls, but the frequency of killing by the nongentled groups was seldom significantly higher than that of the nongentled sham-lesioned controls. Gentling caused a slight enhancement of killing in the lesioned animals and a slight attenuation of killing in the sham lesioned animals. Preoperative gentling attenuated reactivity to the experimenter in animals with lesions of the lateral septum but not in those with lesions of the medial accumbens nucleus or the medial hypothalamus. The observation that preoperative gentling tends to increase mouse killing confirms previous observations. The finding that preoperative gentling attenuates reactivity following septal but not medial accumbens or medial hypothalamic lesions suggests that these structures subserve different functions in the inhibitory modulation of defensive behavior.
Mouse killing in rats: a comparison of spontaneous killers and rats with lesions of the medial hypothalamus or the medial accumbens nucleus.
Mouse killing was observed and videotaped at forty-eight hr following surgery in rats with lesions of the medial hypothalamus or the medial accumbens. The initial attacks and killing bites of the lesioned rats were directed at the anterior dorsal surface, predominantly to the regions of the neck, shoulders, and thorax and did not differ from those of spontaneous mouse killing rats. The latency to attack was significantly shorter for the lesioned animals but the time required to kill following the attack tended to be longer. Lesioned animals spent significantly more time biting the prey following the kill and left significantly more bite marks on the prey than did the spontaneous killers. When the dead prey was moved about the cage following the kill, the lesioned animals showed a significantly greater tendency to attack it than did the spontaneous killers. Following the test of mouse killing, each rat was successively exposed to a freshly killed mouse, a cotton wad, and a wood block. The lesioned animals attacked the dead mouse and the cotton wad as though they were live mice whereas the spontaneous killers did not. These results suggest that while the killing is similar for lesioned and spontaneous killers, the lesioned animals show a heightened response to the killing experience. This is manifested in an exaggeration of attack behaviors toward prey and prey-like stimulus objects following an initial killing experience.
Nutrition-related factors in acutely injured patients.
Parameters thought to reflect nutritional status were assessed in 25 critically ill postoperative patients who had been acutely injured. Results were compared with those fom a group of 28 critically ill postoperative patients who had not sustained trauma. The anthropometric measures were significantly better preserved in the previously healthy and presumably well-nourished trauma patients, but striking abnormalities were observed in both groups in albumin and transferrin levels, in the lymphocyte count, and in skin test reactivity. The latter findings suggest the influence of non-nutritional factors at least in the acutely injured patient. Anergy, although frequently observed in both groups of patients, was not predictive of mortality nor did the 44 surviving patients differ significantly in any of the other measured parameters from the nine patients who died. We conclude that, at present, the need for nutrition therapy for the acutely injured patient is best determined on traditional clinical grounds.
Stimulation of the murine immune system by anti-IgD antibodies: a polyclonal model of B-lymphocyte activation by a thymus dependent antigen.
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Sulfonylureas do not affect insulin binding or glycemic control in insulin-dependent diabetics.
Sulfonylureas alone are ineffective in the therapy of insulin-independent diabetes mellitus (IDDM). These agents, however, might serve as an adjunct to insulin treatment if they directly affect insulin binding to its receptor. We studied 11 patients with IDDM to determine whether chlorpropamide acts directly on the insulin receptor and whether it could augment the effect of insulin on glycemic control. Mean tracer insulin binding to both peripheral monocytes and erythrocytes in 11 poorly controlled patients was normal. Optimization of glucose control by continuous subcutaneous insulin infusion for 7--10 days did not alter insulin binding to either cell type. Addition of chlorpropamide, 250--500 mg/day for another 7--10 days did not affect any aspect of insulin binding (tracer binding, number of receptor sites, insulin sensitivity, or affinity) in either cell type. Insulin binding was not changed in one patient after 3 days of 250 mg/day of the drug and in another after 500 mg/day over 3 mo. The sulfonylurea, in addition, provides no additive effect with insulin on blood glucose levels or insulin doses required to maintain euglycemia. We conclude that short-term use of chlorpropamide in addition to insulin in IDDM does not alter insulin binding to circulating monocytes or erythrocytes. In addition, we were unable to show that this agent is a clinically useful adjunct to insulin in IDDM.
Noncompliance: an unacceptable diagnosis?
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RANF through the eyes of a nursing student.
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Isolation and characterization of cells resistant to ML236B (compactin) with increased levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase.
ML236B is a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) (EC 1.1.1.34), the major regulatory enzyme in cholesterol biosynthesis. This compound inhibits cell growth when present in the culture medium of CHO-K1 cells at a concentration as low as 0.1 micrograms/ml. Addition of the product of the HMG-CoA reductase reaction, mevalonate, to the culture medium prevents the cytotoxic effects of ML236B at a concentration of inhibitor as high as 50 micrograms/ml. Using a stepwise selection procedure, we have obtained two variant cell lines which are resistant to the presence of 8 micrograms/ml of ML236B in the culture medium. The rates of cholesterol synthesis and the cholesterol levels in the variant cell lines, grown in the presence of ML236B, are similar to those of the parental CHO-K1 cell line grown in the absence of inhibitor. Assays of HMG-CoA reductase activity from extracts of variant cells, grown in the presence of inhibitor, reveal that the variant cell lines have an approximately 40-fold higher HMG-CoA reductase activity than does the parental CHO-K1 cell line grown in the absence of inhibitor. However, when the variant cell lines are grown without ML236B in the culture medium, the HMG-CoA reductase activity returns to the parental CHO-K1 level within 5 days, but the resistant phenotype is stable for up to 9 months. We conclude that the variant cell lines are unable to overcome the cytotoxic effects of ML236B by a mechanism which leads to overaccumulation of HMG-CoA reductase which in turn permits normal mevalonate metabolism and cholesterol synthesis to take place.
The insulin receptor in insulin-dependent diabetes mellitus: an in vivo and in vitro study.
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Mouse and weanling rat killing by spontaneous mouse killing rats, and by rats with lesions of the lateral septum or the region ventral to the anterior septum: similarities in killing latency and prey eating.
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