Clinical, viral, and genetic evaluation of equine degenerative myeloencephalopathy in a family of Appaloosas.

A clinical, viral, hematologic , and genetic study was conducted over a 4-year period on a family of Appaloosas with high incidence of clinical ataxia and pathologic features of equine degenerative myeloencephalopathy. Marginal to deficient serum vitamin E (alpha-tocopherol) and blood selenium values were the only other consistent antemortem abnormalities in the affected horses. Members of this family were all descendants of a clinically normal mare and were raised in 3 separate environments with variable quality of feed. All horses had access to pasture grasses. Normal chromosomal karyotypes were found in 11 affected and/or related horses examined. Equine herpesvirus type 2 was isolated from 4 of the horses, but evidence for a role of this virus in the pathogenesis of the disease was not found. The role of antioxidant deficiency in the pathogenesis of neurologic dysfunction in this equine family and in others reported to be affected with equine degenerative myeloencephalopathy remains speculative.

Serum fatty acid profile of elderly tube-fed men in a nursing home.

Severely dependent tube-fed elderly men with dementia in this VA nursing home are nourished exclusively with Isocal, which provides only four fatty acids in amounts over 1% of the total (palmitic, oleic, linoleic, and alpha-linolenic). It has not been proven that the frail elderly can efficiently convert linoleic to arachidonic acid, and alpha-linolenic to eicosapentanoic and docosahexaenoic acids. Therefore, we compared the serum profile of fatty acids in six of the tube-fed elderly men with the profile of six healthy young men eating mixed foods ad lib. Expressed as percent of total fatty acids, arachidonic, eicosapentanoic and docosahexaenoic acids did not differ significantly between the two groups. The data show that linoleic and alpha-linolenic acids satisfy the requirements for omega 6 and omega 3 fatty acids, respectively, in severely impaired elderly men.

Subnormal concentrations of serum selenium and plasma carnitine in chronically tube-fed patients.

Forty-seven tube-fed nursing home patients were investigated with regard to serum or plasma selenium (Se), carnitine, and red blood cell (RBC) glutathione peroxidase (GSH-Px). Thirty-six patients were tube fed with Isocal, and 11 were tube fed with Compleat B, an L-carnitine-containing formula. Eighteen elderly nursing home patients and 10 young adults served as controls. Serum Se and plasma carnitine were lowest (p less than 0.05) in the Isocal patients. In all 36 Isocal subjects, Se was below normal, and in 26% of Isocal patients RBC GSH-Px was also below normal. Free and total carnitine were below normal in most Isocal subjects. All 11 Compleat B patients had subnormal serum Se, but most had normal carnitine concentrations. These data suggest that enteral formulae in nursing homes should contain greater than 100 micrograms Se and on the order of a mmol carnitine/1600 kcal.

Hyponatremia in tube-fed elderly men.

Previous reports have described 5-20% prevalence of hyponatremia in extended care facilities, due largely to drugs or inappropriate antidiuretic hormone secretion. In our 400 bed VA extended care facility, 15 men with organic brain syndrome (Alzheimer's, multi-infarct dementia, anoxic encephalopathy or alcoholism) currently receive Isocal via gastrostomy as the sole source of nutrition. We noted intermittent hyponatremia in about half of these patients, and conducted a chart review to investigate the cause. Mean age was 68 yr (range 46-92); tube feeding duration was 3 mo.-3 yr; 266 Na concentrations were obtained from the charts. Simultaneous with these Na analyses, one of three diets prevailed: (A) mixed foods (3-6 g Na/day) orally before gastrostomy; (B) Isocal supplemented with NaCl to give 2 g Na/day; (C) unsupplemented Isocal providing 1 g Na/day. (B) and (C) had been randomly varied by rotating physicians. Serum Na was directly related to Na intake. On (A), Na was within normal range (135-145 mEq/l) in all men. One patient was hyponatremic during diet (B). During (C), eight patients were hyponatremic. Na was less than 135 mEq/l in 40% of all samples during diet (C) and less than 130 mEq/l in 14%. Changing from diet (A) or (B) to diet (C) caused nearly equivalent declines in Na and Cl; K and HCO-3 were unaffected. No hyponatremic patient took drugs known to cause hyponatremia, or had congestive heart failure, hypoalbuminemia, lipemia or fasting hyperglycemia. At the end of the study, four hyponatremic men were changed from (C) to (B); serum Na became normal in all four patients, without edema or hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)