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Biomedical subjects

L D Lewis

Publications and source records attributed to L D Lewis.

At least 73 records · Page 4Linked to original sources
PubMed1984

Urinary acidification in the prevention and treatment of feline struvite urolithiasis.

Two groups of 12 cats were fed ad libitum an experimental dry expanded ration high in magnesium (0.37%, dry matter basis) and similar to most commercial dry cat foods in all other nutrients. The diet of one of the groups contained 1.5% ammonium chloride, which was added to the diet before processing. Urethral obstruction developed twice in 7 of the 12 cats fed the ration without ammonium chloride. Of the 5 remaining cats in that group, 2 had calculi in the urinary bladder and urethra at necropsy. In contrast, only 2 of the 12 cats fed the ration containing ammonium chloride had urethral blockage once; neither cat had another blockage. Both cats had been catheterized twice as paired controls before urethral obstruction. One of these 2 cats died from a urinary tract infection apparently introduced through the indwelling catheter, and at necropsy there were 2 small calculi in the urethra. At the end of the study, only 1 other cat fed the ammonium chloride diet had a calculus in the urinary bladder at necropsy; this cat had not had a urethral obstruction throughout the study. After each cat had 2 urethral blockages, its diet was changed. Four cats were fed the ration containing ammonium chloride and 3, a dry, commercial ration. Of the 4 cats fed the diet containing ammonium chloride, none developed another urethral obstruction within 6 months, and at necropsy, no calculi were in the urinary bladder or urethra. Two of the 3 cats fed the commercial ration experienced urethral blockage within 3 months. These 2 cats were then fed the diet containing ammonium chloride.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonium Chloride↗
PubMed1984

Treatment and prevention of feline struvite urolithiasis.

A diet providing less than 20 mg of magnesium per 100 kcal that maintains urine pH near 6.0 3 to 5 hours after eating, or a diet providing this amount fo magnesium (see Table 2) with 1 gm of ammonium chloride or 1.5 gm of dl-methionine added daily, should be fed for 1 to 3 months to dissolve struvite uroliths (see Fig. 1). The low-magnesium diet should be fed indefinitely to prevent recurrence, because struvite urolithiasis and all of its effects (hematuria, pollakiuria, and/or complete to partial obstruction to urinary excretion) recurs repeatedly in cats that have previously experienced the condition if they are returned to regular cat food. In contrast, if a diet low in magnesium is fed, recurrence is uncommon. For cats that have never been affected, feeding a low-magnesium ration is unnecessary. For all cats, the following measures are recommended: encourage exercise, allow frequent urination, prevent obesity, decrease confinement, keep the litter box clean, and always have palatable water readily available.

Animal Feed↗
PubMed1984

Canine urolithiasis: diagnosis and treatment.

Over 97% of all uroliths in males less than a year of age and in females are phosphate, excluding males with portosystemic shunts and male Dalmatians . Uroliths in male Dalmatians usually are composed of urate. Uroliths associated with Staphylococcus aureus urinary tract infection are phosphate. About 60% of uroliths in adult male Basset Hounds , Bulldogs , Chihuahuas , Irish Terriers and Yorkshire Terriers are cystine. In males of other breeds, as high as 60% of uroliths are phosphate. Feeding a calculolytic diet (s/d: Hill's) results in phosphate urolith dissolution in 2-20 weeks. Long-term feeding of the calculolytic diet is not recommended, nor is use after surgery and in pregnant, lactating or growing dogs and in those with heart failure, edema, ascites or pleural effusions. Uroliths recur in 20-50% of affected dogs without subsequent dietary alteration. Use of a urolith-prevention diet (u/d: Hill's) is recommended if urolithiasis recurs.

Animals↗
PubMed1982

A benign motor neuron disorder: delayed cramps and fasciculation after poliomyelitis or myelitis.

Two patients had a delayed syndrome of benign fasciculation after complete recovery from paralytic poliomyelitis and a third had the syndrome after an attack of purely motor myelitis. Myalgia was prominent in all three, and two had frequent cramps. Denervation hypertrophy occurred in two. The patients were observed for at least three years, and no new weakness was seen. These cases suggest that some chronic diseases of motor neurons may be benign.

Adult↗
PubMed1982

Colostrum deficiency in mule deer fawns: identification, treatment and influence on neonatal mortality.

Glutaraldehyde coagulation test, zinc sulfate turbidity test, and total protein refractometry were adapted for use in detecting failure of passive transfer of colostral immunoglobulins to mule deer fawns (Odocoileus hemionus). The results of all three tests were similar. Serum total protein concentration was directly correlated to gamma globulin concentration and gave the best indication of morbidity and mortality. Thirteen of 13 fawns with serum total protein concentrations of 5 g/dl or less at 1 to 7 days of age developed diarrhea and died before 17 days of age. Only 1 of 14 fawns having a serum protein concentration above this level became sick and died. Seven of 13 fawns that had serum total protein concentrations of 5 g/dl or less, and that had already developed diarrhea, were given 20 ml of plasma per kg body weight. Although this increased their serum gamma globulin concentrations 0.3 g/dl, none survived. Administration of bovine colostrum to one fawn increased its serum gamma globulin concentration suggesting that mule deer fawns are able to absorb gamma globulins from bovine colostrum.

Animals↗
PubMed1981

Prostaglandins and their metabolites in the gastrointestinal tract of Yucatan miniature swine.

Concentration of prostaglandins E1, E2, F2alpha, and 15 keto, 13, 14-dihydro F2alpha (MPF2alpha), were measured in gastric, duodenal, jejunal, and ileal mucosa, and in the luminal contents of these gastrointestinal segments in miniature swine at 30, 60, and 120 min after they ingested a liquid nutrient meal. Large quantities of E1 and F2alpha were present in gastric contents at 30 min with lesser amounts of E2 and MPF2alpha. The concentrations of E1, E2, and F2alpha in the gastric contents decreased progressively with time after feeding. The total quantity and the concentrations of E1 and F2alpha decreased with passage of ingesta through the duodenum and jejunum. Mucosal concentrations of E1 and F2alpha were greatest in the duodenum and proximal jejunum and lowest in gastric mucosa. These results indicate that there is considerable production and metabolism of prostaglandins in the gastrointestinal tract, with major amounts secreted into the luminal contents of the stomach and duodenum after food intake.

Alprostadil↗
PubMed1981

Effects of osmolality of liquid nutrient diets on plasma equilibration of water and carbohydrate in Yucatan miniature swine.

Osmolality of a liquid diet was varied from 250 to 700 mOsm/kg by altering the amount of sucrose and corn syrup solids, while maintaining the same level of calories, protein, and electrolytes. The appearance of 3H and 14C in blood plasma were monitored during a 4-h period after pigs voluntarily consumed one of five diets labeled with 3H2O and U-14C-sucrose. Plasma osmolality and sodium and potassium concentrations in plasma did not differ among the diets. Postprandial plasma glucose concentration response to the diets varied both between and within treatments. The rates of radioactive tracer appearance in plasma suggest that water and carbohydrate absorption were accelerated with increasing osmolality of diet up to 700 mOsm/kg.

Absorption↗
PubMed1981

Effects of osmolality of liquid nutrient diets on meal passage and nutrient absorption in Yucatan miniature swine.

The effects of varying the osmolality of liquid nutrient diets on the absorption of water, electrolytes, and carbohydrate from the small intestine were studied in Yucatan miniature swine. Pigs were killed and their gastrointestinal contents recovered at either 30 or 60 min after consuming liquid diets adjusted to 340, 450, 540, or 700 mOsm/kg and labeled with 3H2O, 22NaCl, U--14C-sucrose, and 51Cr-EDTA as a passage marker. Intragastric dilution and gastric emptying were not effected by diet osmolality. Gastric contents of all pigs converged toward 450 mOsm/kg, and osmolality of small intestine contents did not differ between diets. The absorption of carbohydrate, water, sodium, and potassium from jejunal contents increased with increasing osmolality of the diets. The rates of appearance of 3H, 22Na, and 14C in plasma also increased with increasing diet osmolality. These findings suggest that moderately hyperosmotic liquid diets may be beneficial, as compared with isoosmotic diets.

Absorption↗
PubMed1980

Dietary fat and exercise conditioning effect on metabolic parameters in the horse.

Four isocaloric diets containing 4, 8, 12 and 16% dietary fat (as soybean oil) were fed to four horses at four intervals according to a Latin square design. After 3 weeks of conditioning at each interval, diet effects were evaluated by trotting all horses at 3.2 m/sec for 6 hours. Pre- and posttrotting responses were measured in muscle and liver glycogen, serum long-chain fatty acids, serum electrolytes, serum enzymes, serum cholesterol, plasma glucose, packed cell volume and hemoglobin. Dietary fat was highly correlated with exercise-induced plasma glucose changes and with cholesterol concentrations. Regardless of the diet, linoleate concentration was about eight times higher than that of the other fatty acids, and it increased slightly as dietary fat levels increased. Stearate concentration also increased with increasing dietary fat but palmitic and oleic acid decreased. Increases in fat intake also resulted in slight increases in liver glycogen at the resting level. Conditioning resulted in a significant decrease in exercise-induced fluctuations of serum enzymes and electrolytes but significantly increased elevations of plasma long-chain fatty acid concentrations. Resting muscle glycogen increased by 37% during the study as a result of conditioning, but there was no effect on liver glycogen at rest or after exercise. Feeding of the four levels of dietary fat in the form of soybean oil had no adverse effects and proved a safe and efficient method of providing concentrated energy to working horses.

Animals↗
PubMed1980

Effect of dietary calcium, magnesium, and phosphorus on phosphate urolithiasis in rats.

Female Wistar rats were fed a basal diet containing various concentrations of calcium, phosphorus, and magnesium: calcium and phosphorus at 0.4, 0.5, 0.8, 1.0, 1.5, and 2 per cent and magnesium at 0.2, 0.4, 0.8, and 1 per cent of the diet dry matter. Two types of uroliths developed: magnesium phosphate in the renal pelves, bladders, and/or ureters of rats fed rations containing 1 per cent magnesium with either 1.0 or 0.5 per cent phosphorus and calcium phosphate uroliths in the renal tubules at the corticomedullary junction of rats fed rations containing phosphorus equal to or greater than 0.8 per cent and magnesium equal to or less than 0.8 per cent. The incidence and severity of calcium phosphate uroliths were reduced by increasing the magnesium concentration in the diet from 0.2 to 0.8 per cent and by increasing the calcium-to-phosphorus ratio to greater than 1. Results of this study indicated that the interactions among dietary calcium, magnesium, and phosphorus seemed to affect the incidence, severity, and type of uroliths in rats.

Animals↗
PubMed1979

Techniques for evaluating humoral and cell-mediated immunity in mule deer fawns (Odocoileus hemionus).

Twenty mule deer fawns (Odocoileus hemionus) were removed from their dams 48 h after birth, and hand-reared. Methods for monitoring their immune capability are described. Passive humoral immunity was determined by serum protein electrophoresis. Active humoral immunity following Clostridium toxoid vaccination was determined by immunodiffusion. Cell-mediated immunity was assayed using contact sensitization to 1-nitro, 2,4-dichlorobenzene (DNCB).

Animals↗
PubMed1978

Pathophysiologic changes due to coronavirus-induced diarrhea in the calf.

Extensive water, sodium, chloride, bicarbonate, and potassium losses occur in the diarrheal calf. The water loss is entirely from the extracellular space. In severe cases, hypovolemic shock occurs with the blood volume decreased by as much as one-half. Acidosis, which results from fecal bicarbonate loss, lactic acidosis, and renal dysfunction, results in tissue buffering, which in turn causes the efflux of cellular potassium ions. Although there is a total body potassium deficit, plasma potassium concentration is increased. This, in conjunction with an intracellular deficit, causes weakness, lethargy, and potassium cardiotoxicosis resulting in death. Hypoglycemia also contributes to the weakness and lethargy seem as calves become moribund. These losses from the body and shifts in fluids and electrolytes must be understood to develop the most effective rationale for supportive therapy.

Acidosis↗