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M Jones

Publications and source records attributed to M Jones.

At least 1,063 records · Page 59Linked to original sources
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The effects of anticalcification treatments on bioprosthetic heart valves implanted in sheep.

Several preimplantation processes have been shown to inhibit the calcification of pieces of porcine aortic valves and of bovine parietal pericardium implanted subcutaneously in rats. To investigate the effectiveness of these processes in modifying the calcification of bioprosthetic valves implanted in an intracardiac position, mitral and tricuspid valve replacements were performed in young sheep. Bioprosthetic valves treated with the following preimplantation processes were studied: 1) surfactants, including sodium dodecyl sulfate, polysorbate-80, Triton X-100 and N-lauryl sarcosine; 2) covalently bound aminohydroxypropane diphosphonic acid; 3) toluidine blue; and 4) incorporation of polyacrylamide into valvular tissues. Quantitative calcium analyses showed that only the surfactants substantially reduced calcification of bioprostheses implanted in intracardiac positions. This effect was evident only in porcine aortic valvular bioprostheses, and not in pericardial bioprostheses. Triton X-100 and N-lauryl sarcosine not only reduced calcification but also induced alterations that decreased the durability of the valves. Toluidine blue decreased calcification to a degree that was statistically significant but not biologically important, while polyacrylamide incorporation and diphosphonate binding increased calcification. Thus, data regarding anticalcification treatments obtained from subcutaneous implantation studies in small animal models should be interpreted cautiously and validated by studies with intracardiac valvular implantation in large animals.

Animals↗
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Sharing the care.

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Female↗
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Simultaneous human forearm and calf metabolic exchange.

Simultaneous forearm and leg metabolic exchange studies were performed to compare metabolic exchange and change in metabolic activity over time across the forearm and calf skeletal muscle beds in response to nutritional treatment. Seven postoperative upper-gastrointestinal resection patients received intravenous nutrition (IVN) for 10 days. Immediately before IVN was begun, simultaneous ipsilateral forearm and calf blood flow with arterial and venous sampling for plasma glucose and free fatty acids (FFAs), and whole-blood glycerol, lactate, pyruvate, and nitrogen were measured. After 10 days of IVN, these parameters were repeated in carefully standardized steady-state conditions. Although there were no differences between the arm and the leg with mean flux measurements, correlation of arm and leg flux values were only significant for FFA (p < 0.01) and blood nitrogen (p < 0.05). Forearm and leg metabolic exchange results were not in sufficient agreement to permit reliable use of these results interchangeably for individuals. Errors in blood flow measurement appear to be a major determinant of the poor relationship between forearm and leg flux measurements (limits of agreement 3.32-4.72 ml.dl-1 tissue.min-1). In conclusion, both forearm and leg metabolic exchange studies can be used to show the metabolic effects of treatment when groups of subjects are studied, but variability of the methods used result in poor agreement for the measurements of an individual.

Aged↗
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Picking up the pieces.

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Hospital Restructuring↗
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Travel precautions.

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Adult↗
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The activity of N-(hydroxymethyl) melamines in fresh human ovarian tumour cells and xenografts.

Trimelamol (TM) was developed as a water soluble analogue of the oral chemotherapeutic agent hexamethyl-melamine (HMM), to be administered i.v., in an effort to avoid dose limiting emesis. Because of formulation difficulties due to its inherent instability the development of TM was halted. In vivo studies using a human ovarian cancer xenograft model PXN/65 showed TM to be curative in the dose range of 15-60 mg/kg i.p. daily x 5, for 4 weeks. Conversely, HMM given at the highest dose (60 mg/kg i.p., or 90 mg/kg p.o.) indicated only very modest tumour growth delays. In vitro chemosensitivity testing using primary ovarian tumour cultures showed that in 12/23 cases indicating reduced sensitivity to cisplatin or carboplatin, sensitivity to TM was increased. TM was curative in the carboplatin-resistant HX 110P human ovarian cancer xenograft and promising activity was seen in the MX-1 human breast cancer xenograft. In spite of enhanced stability in aqueous solution and good in vitro cytotoxicity, the TM analogues CB 7669 (triscyanomethyl) and CB 7639 (tristrifluoroethyl) showed disappointing in vivo antitumour activity which may be explained by the need for prolonged exposure. TM analogues with intermediate stability are currently under development in an effort to further the clinical development of this promising group of antitumour agents.

Altretamine↗
PubMedDate not supplied

Clients express preference for one-stop sexual health shop.

The concept of sexual health is becoming more prominent. However, health services relating to the maintenance of sexual health do not necessarily use the available resources to their best advantage. This paper examines developments in the area of sexual health and presents the results of a survey carried out in Eastbourne and Ipswich, which indicates that attenders of various clinics dealing with sexual health would welcome services such as family planning and genitourinary medicine being combined on one site.

Community Health Nursing↗
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Modification of an amino acid solution for peritoneal dialysis to reduce risk of acidemia.

OBJECTIVE: Some patients develop a mild acidemia during treatment with amino acid-based peritoneal dialysis solutions due to hydrogen ion produced by metabolism of lysine, arginine, and methionine. In this study we modified the formulation of such a solution by reducing these amino acids and adding anionic amino acids so as to provide minimal net acid production. DESIGN: A modified formula (MF) was compared to a conventional formula (CF) of the solution in a randomized cross-over study in 12 stable continuous ambulatory peritoneal dialysis patients. Patients were given each solution for 14 days without a wash-out period. Each patient replaced one or two dextrose dialysis exchanges with amino acid solution, depending upon oral protein intake and body weight. Total intake (oral protein plus amino acids absorbed) was equivalent to 1.1-1.3 g protein/kg body weight/day. Plasma bicarbonate and urea were assessed at the beginning and end of each 14-day period. RESULTS: In the group as a whole, without regard to the order in which the solutions were given, patients had a decrease in serum bicarbonate with CF and an increase in bicarbonate when they received MF. Similar trends were observed regardless of the order in which the solutions were administered. Serum urea did not differ between the two solutions. CONCLUSION: The results suggest that patients are less prone to develop acidemia when receiving MF as opposed to CF. Further studies will be necessary to determine the long-term effects and the relative nutritional benefits of the two solutions.

Aged↗