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Biomedical subjects

H M Anderson

Publications and source records attributed to H M Anderson.

13 recordsLinked to original sources
PubMed2001

Type II tumour necrosis factor-alpha receptor (TNFR2) activates c-Jun N-terminal kinase (JNK) but not mitogen-activated protein kinase (MAPK) or p38 MAPK pathways.

The pleitropic actions of tumour necrosis factor-alpha (TNF) are transmitted by the type I 55 kDa TNF receptor (TNFR1) and type II 75 kDa TNF receptor (TNFR2), but the signalling mechanisms elicited by these two receptors are not fully understood. In the present study, we report for the first time subtype-specific differential kinase activation in cell models that respond to TNF by undergoing apoptotic cell death. KYM-1 human rhabdomyosarcoma cells and HeLa human cervical epithelial cells, engineered to overexpress TNFR2, displayed c-Jun N-terminal kinase (JNK) activation by wild-type TNF, a TNFR1-specific TNF mutant and a TNFR2-specific mutant TNF in combination with an agonistic TNFR2-specific monoclonal antiserum. A combination of the TNFR2-specific mutant and agonistic antiserum elicited maximal endogenous or exogenous TNFR2 responsiveness. Moreover, alternative expression of a TNFR2 deletion mutant lacking its cytoplasmic domain rendered the cells unable to activate JNK activity through this receptor subtype. The profile of JNK activation by TNFR1 was more transient than that of TNFR2, with TNFR2-induced JNK activity also being more sensitive to the caspase inhibitor, benzyloxycarbonyl-Val-Ala-DL-Asp-fluoromethylketone. Conversely, only activation of the TNFR1 could stimulate mitogen-activated protein kinase (MAPK) or p38 MAPK activities in a time-dependent manner. The role of TNFR2 activation in enhanced apoptotic cell death was confirmed with agonistic monoclonal antisera in cells expressing high levels of TNFR2. Activation of TNFR2 alone elicited cell death, but full TNF-induced death required stimulation of both receptor types. These findings indicate that efficient activation of TNFR2 by soluble TNFs is achievable with co-stimulation by antisera, and that both receptors differentially modulate extracellular signal-regulated kinases contributing to the cytokine's cytotoxic response.

Antigens, CD↗
PubMed2001

Stimulation of stress-activated but not mitogen-activated protein kinases by tumour necrosis factor receptor subtypes in airway smooth muscle.

The multifunctional cytokine tumour necrosis factor-alpha (TNF) displays many physiological effects in a variety of tissues, especially proliferative and cytotoxic actions in immunological cells. Recently, we uncovered an important new mechanism by which TNF can sensitise airway smooth muscle (ASM) to a fixed intracellular Ca2+ concentration which in vivo would produce a marked hypercontractility of the airways. Here, we report that both 50-60 kDa type I TNFR (TNFR1) and 70-80 kDa type II TNFR (TNFR2) receptor subtypes were expressed in ASM cells and selectively activated the stress kinases, c-Jun N-terminal kinase and p38 mitogen-activated protein kinase (p38 MAPK). However, TNF caused no activation of p42/p44 MAPK or cytosolic phospholipase A(2) activity. In contrast, TNF stimulation of the TNFR1, but not the TNFR2, elicited nuclear factor-kappaB transcription factor function, a species known to be important in mediation of certain inflammatory cellular responses. This is the first report of TNF receptor subtypes in ASM cells causing selective kinase activation, which may prove important in therapeutic strategies for treating immune airway disorders such as chronic obstructive pulmonary disease and asthma.

Animals↗
PubMed2000

Selective down-regulation of the G(q)alpha/G11alpha G-protein family in tumour necrosis factor-alpha induced cell death.

Investigations into the regulation of heterotrimeric GTP-binding protein alpha-subunits in models of tumour necrosis factor-alpha (TNF)-induced cell death, revealed the selective down-regulation of the G(q)alpha/G11alpha family of G-proteins. The human HeLa and murine L929 cells treated with recombinant human TNF for up to 24 h displayed down-regulated G(q)alpha/G11alpha family protein levels, but not G(s)alpha, G(i)alpha and G(o)alpha protein levels as determined by Western analyses. This effect of TNF was observed in a concentration--and time-dependent manner, consistent with the profiles of TNF-induced cell death observed. Moreover, the functioning of G(q)alpha/G11alpha family proteins were found to be impaired in TNF-treated cells, as measured by agonist-induced [Ca2+]i release. In contrast, G(s)alpha activity was unaltered by TNF-treatment, determined by measurement of agonist-induced intracellular cyclic AMP generation. These findings in TNF-induced cytotoxic models, indicate a novel 'cross-talk' mechanism by which TNF alters Ca2+-signalling mechanisms, which may contribute towards the apoptotic and necrotic cell death.

Animals↗
PubMed2000

Unmodified calcium concentrations in tumour necrosis factor receptor subtype-mediated apoptotic cell death.

Tumour necrosis factor-alpha (TNF) receptors mediate a variety of effects dependent on cell type. A role for Ca2+ in TNF-induced death remains uncertain. Here we investigated restricting intracellular/extracellular Ca2+ in HeLa epithelial carcinoma cells expressing low and high levels of p75TNFR receptor subtype and KYM-1 rhabdomyosarcoma cells, models of rapid TNF-induced apoptosis. Ca2+ -chelators EGTA and BAPTA-AM as well as microsomal Ca2+ -ATPase inhibitor thapsigargin, did not alter TNF-induced death. TNF was also unable to alter resting [Ca2+]i levels which remained < 200 nM even during times when these cells were undergoing apoptotic cell death. These findings indicate no role for modulated Ca2+ concentrations in TNF-induced apoptotic cell death.

Antigens, CD↗
PubMed1993

Innovation through collaboration.

In light of the Canadian Nurses Association's position that the baccalaureate degree would be the requirement for entry to practice by the year 2000, plus evidence of a rapidly changing health care system, changing client characteristics, and on-going economic constraints, administrators of nursing programs in Edmonton recognized the need for a more process-oriented curriculum to prepare nurses to be more capable of facing future challenges. Not surprisingly, limited funds and differing human and material resources meant they could not complete a major curriculum change individually. Collaboration proved to be the key that increased access to baccalaureate nursing education in Alberta.

Canada↗
PubMed1987

Deep venous thrombosis and pulmonary embolism. Risk of subsequent malignant neoplasms.

We conducted a noncurrent prospective study of all Olmsted County, Minnesota, residents who had had a lower-extremity venogram, pulmonary angiogram, or lung scan performed because of suspicion of deep venous thrombosis or pulmonary emboli. One hundred thirteen cancer-free patients were followed for 386 person-years from the date of procedure. Nine subsequent cancers were observed compared with 4.5 expected (relative risk, 2.0; 95% confidence interval, 0.9 to 3.8), using total cancer incidence rates for the Rochester, Minn, population. Five hundred seventeen cancer-free controls were followed for 2072 person-years. Twenty subsequent cancers were observed compared with 11.6 expected, yielding a relative risk of 1.7 (95% confidence interval, 1.1 to 2.7). When cases and controls were compared directly, no statistically significant difference in cancer-free survival was found.

Follow-Up Studies↗
PubMed1985

Angioendotheliomatosis associated with histiocytic lymphoma. Response to systemic chemotherapy.

A patient with cutaneous lesions consistent histologically, ultrastructurally, and immunohistochemically with angioendotheliomatosis is described. The cutaneous lesions appeared 14 months prior to the diagnosis of histiocytic lymphoma of the retroperitoneum. Both the cutaneous lesions and the lymphoma responded well to systemic chemotherapy consisting of cyclophosphamide, hydroxydoxorubicin, vincristine, and prednisone.

Aged↗
PubMed1976

Use of duodenal drainage in the diagnosis of acalculous gallbladder disease.

Because of overreliance on oral cholecystograms, we have re-evaluated a little used laboratory test, duodenal drainage. In a series of 56 patients with normal oral cholecystograms and upper GI series who underwent duodenal drainage and cholecystectomy, 53 (95%) were found to have positive microscopic examinations. We think duodenal drainage is a safe, simple test which should be used as an adjunct to history and physical examination and oral cholecystography. In regard to clinical follow-up, 96 per cent of patients followed were judged to have excellent-to-good results.

Adult↗