Text Size

Site Search powered by Ajax

Abstracts

Abstracts

Arachidonic Acid

Arachidonic Acid

While there are many reports of studies that fed arachidonic acid (AA) to animals, there are very few reports of AA feeding to humans under controlled conditions.

The basal (low-AA) diet consisted of natural foods (30 en% fat, 15 en% protein, and 55 en% carbohydrate), containing 210 mg/d of AA, and met the recommended daily allowance for all nutrients. The high-AA (intervention) diet was similar except that 1.5 g/d of AA in the form of a triglyceride containing 50% AA replaced an equal amount of high-oleic safflower oil in the basal diet.

The main indices studied were the fatty acid composition of the plasma, red blood cells, platelets, and adipose tissue; in vitro platelet aggregation, bleeding times, clotting factors; immune response as measured by delayed hypersensitivity skin tests, cellular proliferation of peripheral blood mononuclear cells in response to various mitogens and antigens, natural killer cell activity, and response to measles/mumps/rubella and influenza vaccines; the metabolic conversion of deuterated linoleic acid to AA and the metabolic fate of deuterated AA in the subjects on and off the high-AA diet; and the production of eicosanoids as measured by excretion of 11-DTXB2 and PGI2-M in urine.

The results of these studies will be presented in the next five papers from this symposium.

Nelson GJ et al., A human dietary arachidonic acid supplementation study conducted in a metabolic research unit: rationale and design. Lipids, 1997 Apr, 32:4, 415-20.

Blood Coagulation

Blood Coagulation

Arachidonic acid (AA) is the precursor of thromboxane and prostacyclin, two of the most active compounds related to platelet function. The effect of dietary AA on platelet function in humans is not understood although a previous study suggested dietary AA might have adverse physiological consequences on platelet function.

The in vivo bleeding times did not show a significant difference before and after the subjects consumed the high-AA diet. Platelets exhibited only small changes in their AA content during the AA feeding period. The results from this study on blood clotting parameters and in vitro platelet aggregation suggest that adding 1.5 g/d of dietary AA for 50 d to a typical Western diet containing about 200 mg of AA produces no observable physiological changes in blood coagulation and thrombotic tendencies in healthy, adult males compared to the unsupplemented diet.

Thus, moderate intakes of foods high in AA have few effects on blood coagulation, platelet function, or platelet fatty acid composition.

Nelson GJ et al., The effect of dietary arachidonic acid on platelet function, platelet fatty acid composition, and blood coagulation in humans. Lipids, 1997 Apr, 32:4, 421-5.

Blood Flow

Blood Flow

Although the rules about flows seem complex and even at times suggest chaos, some general principles can be extracted and used by the radiologist. Normal arteries damp disturbances, tolerate our catheters well, and generally cause the "blood"'s slipstreams to swirl. It seems that the swirls and the energy that accompanies the passage of those swirls are prime determiners of the development of degenerative changes, most importantly of "atherosclerosis" and berry aneurysms.

The MR scanner not only allows calculation of global flow in vessels but also analyzes individual slipstreams.

Control analysis applied to the whole body: control by body organs over plasma concentrations and organ fluxes of substances in the blood. Brown-GC. Biochem-J. 1994 Jan 1; 297 ( Pt 1): 115-22.

Flow dynamics for radiologists. II. Practical considerations in the live human. Kerber-CW; Liepsch-D. AJNR-Am-J-Neuroradiol. 1994 Jun; 15(6): 1076-86.

Blood Sampling

Blood Sampling

Assessed the reactions of parents and their children to the request for a blood sample and an attempt to take blood.

866 questionnaires were returned; 790 were from parents of children in whom an attempt to take blood had been successful. Thirteen per cent said that their child had given blood previously. About 30% discussed the request with the family doctor or nurse. Some 90% said that they were given enough information and that the phlebotomist was sympathetic. Attempting to take blood caused upset in over 50%, which, in most, lasted for less than five minutes. A substantial minority were upset for up to 30 minutes and a few much longer.

Bruising or bleeding occurred in 20-27%. Degree and duration of upset were both adversely associated with a failed attempt to obtain blood.

The majority of preschool children experienced no more than a little upset of short duration after an attempt to take blood, but a substantial minority exhibited a greater degree of upset. These responses should be taken into account when assessing the benefits and risks of the procedure. The best equipment and expertise should be employed for taking blood as successful attempts are less upsetting.

Davies PS et al., Parents' and children's reactions to taking blood in a nutrition survey. Arch Dis Child, 1996 Oct, 75:4, 309-13.

Cerebral Blood Flow

Cerebral Blood Flow

The patients showing "dizziness" or "syncope" when tilted to a 70 degrees upright position exhibited characteristic reverse flow at the end-diastolic phase on the Doppler flow image of both the common carotid and vertebral arteries. Reverse flow was not seen in any patients who did not have dizziness or syncope.

After subjects were tilted from a supine to a 70 degrees upright position, decrease in the peripheral blood flow of the patients with orthostatic "hypotension" remained unchanged for at least 5 minutes, whereas that of control subjects was recovered within 2 minutes.

Detection of reverse flow by duplex ultrasonography in orthostatic hypotension. Yonehara-T; Ando-Y; Kimura-K; Uchino-M; Ando-M. "Stroke". 1994 Dec; 25(12): 2407-11.

Circulation

Circulation

"Metabolic" control analysis is adapted as a method for describing and analysing the control by organs in the body over the fluxes and concentrations of substances carried in the blood.

Control analysis applied to the whole body: control by body organs over plasma concentrations and organ fluxes of substances in the blood. Brown-GC. Biochem-J. 1994 Jan 1; 297 ( Pt 1): 115-22.

The therapeutic principle, from TCM, was to invigorate blood "circulation" and reduce stasis and to soothe the "liver" and regulate qi, so as to dredge the channels and collaterals. The results were satisfactory.

The application of traditional Chinese medicine (TCM) to the management of "hepatic" "cancerous" "pain". Wang-G; Sun-G; Tang-W; Pan-X. J-Tradit-Chin-Med. 1994 Jun; 14(2): 132-8.

Dietary Fish Oil

Dietary Fish Oil

Triglyceride lowering is the most consistent effect of fish oils, having been observed in Greenland Eskimos and subsequently in controlled clinical trials. Although total cholesterol levels are not altered, LDL levels may rise, especially in hypertriglyceridemic patients. The persistence of the hypotriglyceridemic effect has been documented in two recent trials following large numbers of patients from 6-9 months. These studies also provided evidence that the LDL raising effect may not persist.

The safety of fish oils was also supported in these studies because problems with excessive bleeding and worsening glycemic control did not materialize. However, in one of these studies fish oils proved ineffective in slowing the rate of restenosis after coronary angioplasty.

Harris WS: Dietary fish oil and blood lipids. Curr Opin Lipidol, 1996 Feb, 7:1, 3-7.

Gastrointestinal Bleeding

Gastrointestinal Bleeding

To identify risk factors for gastrointestinal bleeding (GIB) among users of non-aspirin, non-steroidal anti-inflammatory drugs (NANSAIDs).

A total of 120 patients aged over 60 years and using NANSAIDs were hospitalized between January 1988 and September 1992 for GIB related to erosions or ulceration of the gastroduodenal mucosa.

This study identified a group at 'high risk' for GIB which would benefit from the development of a prophylactic therapy.

Hochain P et al., Which patients taking non-aspirin non-steroidal anti-inflammatory drugs bleed? A case-control study. Eur J Gastroenterol Hepatol, 1995 May, 7:5, 419-26.

Hemostatic Factors

Hemostatic Factors

The effects of alpha-linolenic acid (ALA, 18:3n-3), eicosapentaenoic acid (EPA, 20:5n-3), and docosahexaenoic acid (DHA, 22:6n-3) on hemostatic factors were compared.

Healthy subjects (29 women and 17 men aged 20-44 y) received either linseed oil (average ALA intake: 5.9 g/d) or fish oil plus sunflower oil (average EPA + DHA intake: 5.2 g/d) for 4 wk.

Results indicate that supplemented ALA from vegetable oil and EPA and DHA from a marine source have largely parallel effects on hemostatic factors.

Freese R & Mutanen M: Alpha-linolenic acid and marine long-chain n-3 fatty acids differ only slightly in their effects on hemostatic factors in healthy subjects. Am J Clin Nutr, 1997 Sep, 66:3, 591-8.

Hormone-Replacement Therapy

Hormone-Replacement Therapy

Tested the lipid-lowering effects of continuous combined hormone-replacement therapy in hypercholesterolemic postmenopausal women.

Nevertheless, continuous combined hormone-replacement therapy was associated with a high frequency of side effects, including breast tenderness and uterine bleeding. Most bothersome side effects dissipated after an initial adjustment period.

Continuous combined hormone-replacement therapy can produce significant and therapeutic reductions in LDL cholesterol levels in hypercholesterolemic postmenopausal women. After internists become familiar with the expected side effects and their time course, this regimen may provide an effective approach in the management of hypercholesterolemia in postmenopausal women who have not undergone hysterectomy.

Denke MA: Effects of continuous combined hormone-replacement therapy on lipid levels in hypercholesterolemic postmenopausal women. Am J Med, 1995 Jul, 99:1, 29-35.

Newborns and Vitamin K Therapy

Newborns and Vitamin K Therapy

This study evaluated 56 healthy newborn infants in Thailand who were given a single dose of vitamin K (phytonadione) as an injection (1 mg intramuscularly) or an oral dose (2 and 5 mgs). There was no evidence of clinical bleeding or of abnormally low thrombotest values seen in any infants studied.

"Comparison of Oral and "Parenteral" Vitamin K Prophylaxis For The Prevention of Late "Hemorrhage" Diseases of the Newborn", Hathaway, William E., MD, et al, The Journal of Pediatrics, September 1991;119(3):461-464.

Salmon Diet

Salmon Diet

"Salmon" based diet rich in "omega-3" "fatty acids" did not influence bleeding times but did decrease the sensitivity of platelets to ADP and "arachidonic acid", increase mean platelet size, decrease platelet count, and change the "fatty acid" composition of plasma, "red blood cells" and platelet membrane lipids. 40 days after the diet was stopped there was little persistent effect of the n-3 fatty acids in the blood.

"The Effect of a Salmon Diet on Blood Clotting, Platelet Aggregation and Fatty Acids in Normal Adult Men", Nelson, Gary J., et al, Lipids, 1991;26(2):87-96.

 


Follow Applied Health on FaceBook Follow Applied Health on Twitter Follow Applied Health on Pinterest Follow Applied Health on YouTube
 

Cruelty-Free
cruelty free - tested only on humans
We test only on humans