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Biomedical subjects

H D Riordan

Publications and source records attributed to H D Riordan.

8 recordsLinked to original sources
PubMed2001

Cytotoxicity of ascorbate, lipoic acid, and other antioxidants in hollow fibre in vitro tumours.

Vitamin C (ascorbate) is toxic to tumour cells, and has been suggested as an adjuvant cancer treatment. Our goal was to determine if ascorbate, in combination with other antioxidants, could kill cells in the SW620 hollow fibre in vitro solid tumour model at clinically achievable concentrations. Ascorbate anti-cancer efficacy, alone or in combination with lipoic acid, vitamin K3, phenyl ascorbate, or doxorubicin, was assessed using annexin V staining and standard survival assays. 2-day treatments with 10 mM ascorbate increased the percentage of apoptotic cells in SW620 hollow fibre tumours. Lipoic acid synergistically enhanced ascorbate cytotoxicity, reducing the 2-day LC(50)in hollow fibre tumours from 34 mM to 4 mM. Lipoic acid, unlike ascorbate, was equally effective against proliferating and non-proliferating cells. Ascorbate levels in human blood plasma were measured during and after intravenous ascorbate infusions. Infusions of 60 g produced peak plasma concentrations exceeding 20 mM with an area under the curve (24 h) of 76 mM h. Thus, tumoricidal concentrations may be achievable in vivo. Ascorbate efficacy was enhanced in an additive fashion by phenyl ascorbate or vitamin K3. The effect of ascorbate on doxorubicin efficacy was concentration dependent; low doses were protective while high doses increased cell killing.

Antioxidants↗
PubMed2000

Integrative medicine: a paradigm shift in medical education and practice.

The use of alternative/complementary medicine has been increasing considerably. Conventional medicine must begin to address issues related to the use, safety, regulation, research and education of alternative/complementary medicine. Integrative medicine combines conventional medicine and alternative complementary practices. Integrative medicine is an innovative approach to medicine and medical education. It involves the understanding of the interaction of the mind, body and spirit and how to interpret this relationship in the dynamics of health and disease. Integrative medicine shifts the orientation of the medical practice from disease based approach to a healing based approach. It does not reject conventional medicine nor uncritically accepts unconventional practices. Integrative medicine is an effective, more fulfilling human approach to medicine based on the benefit of the patient by following good medicine practices in a scientific manner.

Complementary Therapies↗
PubMed1995

Intravenous ascorbate as a tumor cytotoxic chemotherapeutic agent.

Ascorbic acid and its salts (AA) are preferentially toxic to tumor cells in vitro and in vivo. Given in high enough doses to maintain plasma concentrations above levels that have been shown to be toxic to tumor cells in vitro, AA has the potential to selectively kill tumor cells in a manner similar to other tumor cytotoxic chemotherapeutic agents. Most studies of AA and cancer to date have not utilized high enough doses of AA to maintain tumor cytotoxic plasma concentrations of AA. Data are presented which demonstrate the ability to sustain plasma levels of AA in humans above levels which are toxic to tumor cells in vitro and suggests the feasibility of using AA as a cytotoxic chemotherapeutic agent.

Animals↗
PubMed1986

Differences in human serum copper and zinc levels in healthy and patient populations.

This report is designed to re-examine the use of our presently accepted normal laboratory levels for human serum zinc and copper and to suggest a technique, previously unreported in the literature, to more precisely understand the relationship of serum zinc and copper in health and disease. Data from a patient population of 95 and a healthy population of 115 who met certain criteria are compared.

Adult↗
PubMed1984

Clinical correlations between serum glucose variance and reported symptoms in human subjects.

The evidence presented in this report suggests that, in both a healthy people and patient populations, there are clinical and biochemical (fasting serum glucose) gradations of health and sickness. What is particularly fascinating is the fact that, as one progressively develops a symptomless and signfree subset, the blood glucose levels become more homogeneous, meaning that glucose scores cluster to the mean. This enhances the diagnostic, therapeutic and predictive utility of blood glucose scores. While such clinico-biochemical parallelisms are clear, it is essential to mention the point that they do not necessarily prove cause-and-effect. But our interest has been sufficiently stimulated to study several other possible correlates between biochemical variances and the degree of reported symptomatology.

Adolescent↗
PubMedDate not supplied

Improved microplate fluorometer counting of viable tumor and normal cells.

An improved method has been developed to count cells in situ based on the measurement of esterase activity with carboxyfluorescein diacetate. This sensitive, semiautomated microplate fluorometer assay was able to estimate viable cell numbers over a range of 5 x 10(2) to 2.6 x 10(5) cells/well in a tumor cell line. Sensitivity to 10(3) was demonstrated in two other cell lines. Sub- and supranormal fluorescence events which can be responsible for unreliable readings when using a fluorescence assay for cell counting were quantified in a menadione (cytotoxic agent)/U-87 MG (cell line) model. There was a close correlation between the fluorometer method and Coulter counter method for two different tumor cell lines when this method was performed on cells after sub- and supranormal fluorescence events had ceased.

Cell Count↗