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Biomedical subjects

Gil Hardy

Publications and source records attributed to Gil Hardy.

16 recordsLinked to original sources
PubMed2005

Clogbusting: time for a concerted approach to catheter occlusions?

PURPOSE OF REVIEW: Occlusions of central venous catheters in service are frequent, but the random nature of the problem has resulted in a piecemeal approach to solving it. The purpose of this review is to examine what is known from past and recent publications and to recommend strategies for future investigations. RECENT FINDINGS: Long-term central venous access is a critical part of nutritional support for many patients with intestinal failure. The technique also has wide applicability in oncology, the management of certain types of infections and in organ failure. The causes of occlusion have been found to be multifactorial, including a combination of mechanical obstruction, chemical precipitation, lipid deposition and thrombus formation. Most unblocking strategies have been aimed at cure rather than prevention, and targeted at individual causes of obstruction. The British Pharmaceutical Nutrition Group and home parenteral nutrition patients group (Patients on Intravenous and Nasogastric Nutrition Therapy), member organizations of the British Association for Parenteral and Enteral Nutrition, have recently charged a subcommittee with targeting future research into a more concerted practical and pharmaceutical approach to the phenomenon. SUMMARY: Catheter occlusion is a common problem costing considerable time and money for patients and healthcare professionals, requiring pro-action rather than reaction. None of the existing approaches is a complete answer, and further, coordinated research effort is needed. Endoluminal brushing is gradually gaining acceptance as a 'catch-all' solution once the catheter malfunctions, but understanding how and why catheters become blocked, and developing strategies to prevent occlusion would be a more scientific approach.

Catheterization, Central Venous↗
PubMed2003

Nutraceuticals--a pharmaceutical viewpoint: part II.

PURPOSE OF REVIEW: To review pharmaceutical and pharmacological issues relating to the benefits and risks associated with the use of naturally sourced nutraceuticals when administered singly or in combinations. RECENT FINDINGS: The application of vegetable extracts or dietary supplementation with selenium or antioxidant vitamins results in positive benefits on immunity and other phenomena associated with chronic diseases, ageing and cancer. However, there appear to be no cardiovascular benefits from vitamin mixtures, which may in fact cause harm. Therefore, although recent publications have increased our understanding of the metabolic actions of nutraceuticals, learning to use them to the best advantage is going to require products with uniform and consistent quality. Unfortunately, a single purified substance will not always have the same antioxidant activity, nor provide the same clinical benefits as nutraceutical mixtures and combinations occurring in natural extracts. In order to perform first-class clinical studies to determine safety and efficacy, the stability, compatibility and other pharmaceutical variables inherent in many of these combination products will have to be better controlled. SUMMARY: Nutraceuticals have potent biological actions. Their use is increasing dramatically, and there is growing evidence of clinical benefits. No medicinal products are completely safe so their risks need to be characterized and controlled. Imposing pharmaceutical levels of control and regulation would increase costs and reduce patient access to new products, but the evidence is compelling that closer monitoring of raw materials, processing and formulation will be required to maximize the benefits and minimize the risks.

Aging↗
PubMed2002

Impact of oral L-glutamine on glutathione, glutamine, and glutamate blood levels in volunteers.

OBJECTIVE: We investigated the effect of glutamine supplementation on plasma glutamine (Gln), glutamate (Glu), and whole-blood glutathione (GSH) concentrations in human volunteers. METHODS: Subjects first adapted to a standard diet with known intakes of protein, total GSH, cysteine, methionine, and total Glu (Glu values include Glu and Gln) for 3 d. Plasma Gln, Glu, and whole-blood GSH levels were then measured at 4-h intervals over 24 h. Supplemental oral Gln (0.3 g x kg(-1) x d(-1)) was ingested for 10 d and then 24-h plasma levels of Gln, Glu, and whole-blood GSH were measured. RESULTS: The plasma concentrations of Glu (116%; P = 0.006) and Gln (20%; P = 0.046) were significantly higher, whereas concentrations of GSH were significantly lower (37%; P = 0.00091) after oral Gln supplementation. CONCLUSION: Oral Gln increases Glu and Gln levels in plasma of healthy subjects but does not increase GSH red cell (whole-blood) levels. Thus, GSH biosynthesis and preservation of GHS stores in red blood cells may involve rate-limiting substrates other than Gln.

Administration, Oral↗
PubMed2002

Glutamine in pediatrics: where next?

OBJECTIVE: We reviewed the literature and examined the issues surrounding the use of glutamine in pediatrics and neonatology. METHODS: We reviewed the literature using Medline, Embase, Current Contents, and International Pharmaceutical Abstracts. Additional information was obtained from bibliographic citations and personal communications. RESULTS: Evidence showed that glutamine levels are affected in a number of life stages and conditions. Useful, indicative studies are emerging but many fail to demonstrate significant differences. The problems of researching in this patient population were demonstrated. CONCLUSION: A need for a great deal of further research in this area, including larger multicenter trials, clearly emerged.

Age Factors↗
PubMed2002

Practicalities of glutathione supplementation in nutritional support.

New nutraceutical products for nutritional support and antioxidant therapy such as glutathione require practical advice and information on the indications, methods and routes of administration, dosing (therapeutic drug monitoring), stability and physicochemical compatibility. This review is based on recent clinical and experimental publications in which glutathione has been used as a drug.

Antioxidants↗
PubMed2002

Nutraceuticals: a pharmaceutical viewpoint: I.

PURPOSE OF REVIEW: To review pharmaceutical aspects of selected amino acids, antioxidants and related nutraceuticals, deemed to be important for clinical nutrition. RECENT FINDINGS: New clinical applications of nutraceuticals are increasingly being reported, but there are fundamental differences between formulation, production and the evidence supporting clinical use. Nutraceuticals generally fall within the novel foods and ingredients regulations but their purity, dosage requirements and clinical consequences exceed those of most 'healthfoods'. Replacement of one nutrient or antioxidant is unlikely to correct the cascade of interconnected metabolic abnormalities associated with many diseases. However, it is difficult to ascertain whether the reported benefits of complex mixtures, with little published stability data, are due to one or more individual substrates or some in-vitro interaction between them. Many clinical studies have suffered from inconsistencies of dose, formulation discrepancies and unproven outcome. These contradictory results weaken any firm evidence base to substantiate their effectiveness. SUMMARY: Nutraceuticals are destined to play an important role in future therapeutic developments but their success will be governed by control of purity, safety and efficacy without inhibiting innovation. The straightforward application of pharmaceutical standards, especially across national borders, is likely to be a difficult challenge and could effectively paralyse the industry. Nevertheless more standardized formulations, dosage forms and production controls are called for. A place for nutraceuticals in clinical practice is emerging, but important pharmaceutical and clinical issues need to be addressed by further research.

Antioxidants↗
PubMedDate not supplied

Interleukin-7 dose-dependently restores parenteral nutrition-induced gut-associated lymphoid tissue cell loss but does not improve intestinal immunoglobulin a levels.

BACKGROUND: Without enteral nutrition, the mass and function of gut-associated lymphoid tissue (GALT), a center of systemic mucosal immunity, are reduced. Therefore, new therapeutic methods, designed to preserve mucosal immunity during parenteral nutrition (PN), are needed. Our recent study revealed that exogenous interleukin-7 (IL-7; 1 microg/kg twice a day) restores the GALT cell mass lost during intravenous (IV) PN but does not improve secretory immunoglobulin A (IgA) levels. Herein, we studied the IL-7 dose response to determine the optimal IL-7 dose for recovery of GALT mass and function during IV PN. We hypothesized that a high dose of IL-7 would increase intestinal IgA levels, as well as GALT cell numbers. METHODS: Male mice (n = 42) were randomized to chow, IL-7-0, IL-7-0.1, IL-7-0.33, IL-7-1 and IL-7-3.3 groups and underwent jugular vein catheter insertion. The IL-7 groups were fed a standard PN solution and received IV injections of normal saline (IL-7-0), 0.1, 0.33, 1, or 3.3 microg/kg of IL-7 twice a day. The chow group was fed chow ad libitum. After 5 days of treatment, the entire small intestine was harvested and lymphocytes were isolated from Peyer's patches (PPs), intraepithelial (IE) spaces, and the lamina propria (LP). The lymphocytes were counted and phenotypes determined by flow cytometry (alphabetaTCR, gammadeltaTCR, CD4, CD8, B cell). IgA levels of small intestinal washings were also examined using ELISA (enzyme-linked immunoabsorbent assay). RESULTS: IL-7 dose-dependently increased total lymphocyte numbers in PPs and the LP. The number of lymphocytes harvested from IE spaces reached a plateau at 1 microg/kg of IL-7. There were no significant differences in any phenotype percentages at any GALT sites among the groups. IgA levels of intestinal washings were significantly higher in the chow group than in any of the IL-7 groups, with similar levels in all IL-7 groups. CONCLUSIONS: Exogenous IL-7 dose-dependently reverses PN-induced GALT cell loss, with no major changes in small intestinal IgA levels. IL-7 treatment during PN appears to have beneficial effects on gut immunity, but other therapeutic methods are needed to restore secretory IgA levels.

Animals↗