PubMed Health⌕ Search

Biomedical subjects

J Gilligan

Publications and source records attributed to J Gilligan.

9 recordsLinked to original sources
PubMed1999

Targeted expression of calcitonin gene-related peptide to osteoblasts increases bone density in mice.

The neuropeptide calcitonin gene-related peptide (CGRP) is concentrated in fine sensory nerve endings innervating all tissues, including bone. CGRP inhibits osteoclasts, stimulates insulin-like growth factor I and inhibits tumor necrosis factor alpha production by osteoblasts in vitro. To investigate the role of CGRP in bone in vivo, mice were engineered to express CGRP in osteoblasts by placing the human CGRP gene under the control of the rat osteocalcin promoter (Ost-CGRP tg+ mice). Calvaria cultures from transgene positive (tg+), but not tg- mice, produced bioactive CGRP. Trabecular bone density and bone volume, determined by peripheral quantitative computed tomography and bone histomorphometry, respectively, were higher in tg+ than tg- littermates. This increase in bone volume was associated with an increased bone formation rate. Trabecular bone density decreased in tg+ mice as a result of ovariectomy, but remained higher than in sham tg- mice. Targeting CGRP to osteoblasts appears to favor the establishment of a higher trabecular bone mass in mice.

Animals↗
PubMed1992

Endothelin-I-mediated vasoconstriction: specific blockade by verapamil.

The capacity of three vasodilators that act by distinct mechanisms to reverse endothelin-I-mediated vasoconstriction was studied in 11 healthy nonsmoking male subjects (mean age +/- SEM, 26 +/- 2 years; mean weight +/- SEM, 74 +/- 2 kg) by use of brachial artery infusion and forearm strain-gauge plethysmography. Isoproterenol (cyclic adenosine monophosphate-mediated vasodilation), sodium nitroprusside (cyclic guanosine monophosphate-mediated vasodilation), and verapamil (L-type calcium channel blocker) were compared for capacity to reverse endothelin-I-mediated increase in forearm vascular resistance (FVR). Endothelin-I infusion increased FVR 1.9-fold in the control state. Isoproterenol infusion decreased FVR with or without concurrent endothelin-I infusion; however, at comparable isoproterenol infusion rates, endothelin-I increased FVR similar to the control state (for 5 ng/min isoproterenol, endothelin-I increased FVR 1.85-fold; for 12.5 ng/min isoproterenol, endothelin-I increased FVR 2.03-fold). Similarly, sodium nitroprusside infusion decreased FVR with or without concurrent endothelin-I infusion; however, at comparable sodium nitroprusside infusion rates the endothelin-I increase in FVR was similar to control (for 0.48 micrograms/min sodium nitroprusside, endothelin-I increased FVR 1.89-fold; for 0.96 micrograms/min sodium nitroprusside, endothelin-I increased FVR 2.36-fold). In contrast, verapamil infusion decreased FVR with or without endothelin-I infusion. At a verapamil infusion rate of 19.1 microns/min, endothelin-I increase in FVR was comparable to control (for 19.1 microns/min verapamil, endothelin-I increased FVR 1.36-fold, less than the 1.0-fold increase in the control state; p < 0.05). Isoproterenol and sodium nitroprusside decreased FVR during concurrent endothelin-I infusion but did not reverse the endothelin-I effect. In contrast, verapamil reversed endothelin-I--induced vasoconstriction to control FVR, suggesting a specific antagonism of endothelin-I--mediated increase in FVR.

Adult↗
PubMed1984

Neurological injuries in South Australia: the influence of distance on management and outcome.

It has been shown that in at least two Australian states (New South Wales and South Australia), there is a disproportionately high incidence of lethal neurological injuries in country areas. To determine whether any of this increased rural mortality results from geographical remoteness from specialized hospital services, we have studied prospectively a consecutive series of 153 patients with head injuries (140) or spinal injuries (13), who were transferred to Adelaide, South Australia from country centres during a six month period. Distance appeared to be an occasional cause of delay in instituting expert primary treatment. Of 13 deaths, three resulted from potentially remediable causes (intracranial bleeding, airway obstruction), and in two others difficulties in early supportive care may have contributed to death. First aid sometimes had to be administered by lay persons, and appeared to have been occasionally inadequate. Undesirable delay in transfer from accident site to country hospital was recorded in a few cases; in some of these, private transport was used. Distance was an important cause of delay in transferring patients to Adelaide, since 77% of patients had to travel in excess of 50 km. Thirty patients were brought to Adelaide by medical retrieval teams. These teams, which are centrally co-ordinated, have been useful in extending to country areas the specialized techniques of emergency intensive care and less frequently of operative neurosurgery.

Adolescent↗
PubMed1984

Short-term aluminum administration in the rat. Effects on bone formation and relationship to renal osteomalacia.

Aluminum may be pathogenic in the osteomalacia observed in some patients receiving hemodialysis. To study the early effects of Al on bone growth, bone formation, mineralization, and resorption were measured during short-term Al exposure in the tibial cortex of pair-fed control (C, n = 10), aluminum-treated (AL, n = 9), subtotally nephrectomized control (NX-C, n = 7), and subtotally nephrectomized aluminum-treated (NX-AL, n = 8) rats using double tetracycline labeling of bone. Animals received 2 mg/d of elemental Al intraperitoneally for 5 d/wk over 4 wk. Total bone and matrix (osteoid) formation, periosteal bone and matrix formation, and periosteal bone and matrix apposition fell by 20% in AL from C, P less than 0.05 for all values, and by 40% in NX-AL from NX-C, P less than 0.01 for all values. Moreover, each measurement was significantly less in NX-AL than in AL, P less than 0.05 for all values. Osteoid width did not increase following aluminum administration in either AL or NX-AL. Resorption surface increased from control values in both AL and NX-AL; also, resorptive activity at the endosteum was greater in NX-AL than in NX-C, P less than 0.05. Thus, aluminum impairs new bone and matrix formation but does not cause classic osteomalacia in the cortical bone of rats whether renal function is normal or reduced. These findings may represent either a different response to aluminum administration in cortical bone as contrasted to trabecular bone or an early phase in the development of osteomalacia. Aluminum may increase bone resorption and contribute to osteopenia in clinical states associated with aluminum accumulation in bone.

Aluminum↗
PubMed1980

Legionnaires' disease in South Australia. Four case reports.

Four severe cases of Legionnaires' disease are described. In addition to multilobar pneumonia with respiratory failure, involvement of the central nervous, cardiovascular, renal, hepatic and coagulation systems had occurred. Adult respiratory distress syndrome complicated respiratory management. Early development of acute renal failure was associated with a poor prognosis. Erythromycin was the most commonly used antibiotic. Review of stored pathological material from patients who died from unidentified pneumonias enabled confirmation of the existence of Legionnaires' disease in Australia in 1974.

Adult↗