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Biomedical subjects

L D Rowe

Publications and source records attributed to L D Rowe.

At least 37 records · Page 2Linked to original sources
PubMed1986

Tolerance and effect of chronic dietary cobalt on sheep.

Degeneration and necrosis of the testes and reduced spermatogenesis were recently observed in rats after prolonged intake of dietary cobalt (Co). The objective of the present study was to evaluate the effect of chronic Co intake on testicular and other tissues in sheep. Adult cross-bred rams were dosed daily for 70 days with gelatin capsules containing either 0, 3.0, or 4.5 mg Co/kg body weight. The Co dosages were increased on days 71 to 109 to 0, 10.0 and 15.0 mg Co/kg. Blood and serum samples were collected weekly and the rams were submitted to necropsy on day 109. Tissues were evaluated for histopathological changes and tissue Co residues and testicular spermatid reserves were determined. Highly significant (P less than 0.005) increases in Co levels were present in the blood, liver, kidney and testes of the treated rams. Neither gross nor microscopic lesions were observed in the testes or other tissues. Spermatid reserves remained unchanged. The absence of lesions and nonsignificant alterations in hematological and biochemical determinations indicated that prolonged exposure to Co at the dosages administered did not induce testicular degeneration in sheep and was tolerated without apparent pathological manifestations.

Animals↗
PubMed1986

Delta-aminolevulinic acid dehydratase (EC4.3.1.24) activity in erythrocytes from cattle administered low concentrations of lead acetate.

Four different age groups of cattle, which had never been exposed to Pb, were used to determine normal age-related values for erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity. Acute or chronic Pb intoxication was experimentally induced in young calves, and their ALAD values were compared with the normal values. Results indicated that ALAD of normal bovine erythrocytes increased 2- to 3-fold from 1 week to 9 weeks of age and then slowly returned to the initial (1 week old) value by 9 months of age. Erythrocyte ALAD from cattle greater than or equal to 9 months old was uniform. Because of the age-related changes in normal ALAD of cattle less than 9 months old, the age of an animal should be carefully established and age-matched controls evaluated simultaneously when ALAD is used to assess calves suspected of having Pb poisoning. A significant negative correlation was found between blood Pb concentration and ALAD during the first 24 hours after the initial administration of Pb, indicating a high sensitivity of erythrocyte ALAD to Pb. However, when blood Pb concentrations reached 50 micrograms/dl, ALAD did not change further. Because single ingestions of Pb can raise blood Pb concentrations greater than 50 micrograms/dl, ALAD appears to have little value in differentiating acute from chronic Pb intoxication. Within 7 days after Pb administration ceased, ALAD did not increase significantly, even when calves were given calcium ethylenediaminetetraacetic acid (CaNa2EDTA); however, blood Pb concentration decreased by 50%. The rapid change in blood Pb concentration gave a false indication of a positive treatment effect when no real effect was detected by ALAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effects of amount of whole cottonseed on intake, digestibility, and physiological responses of dairy cows.

In Experiment 1, 27 lactating cows were fed complete rations ad libitum of 0, 15, and 30% whole cottonseed to examine the effects on intake, digestibility, blood gases, and blood metabolites. Dry matter intake declined linearly with increased cottonseed, but because of greater energy density, calculated net energy for lactation intake was not depressed significantly. Ether extract, crude protein, and calcium digestibility increased with cottonseed in the diet. Respiration rates declined with dry matter intake and increased cottonseed feeding; some blood gases were influenced by cottonseed feeding but not in a detrimental way. No data among 13 blood metabolites indicated effects of gossypol toxicity with 30% whole cottonseed in the diet. In Experiment 2, 24 dry, nonpregnant Holstein cows were offered complete rations ad libitum of 15, 35, and 55% whole cottonseed to measure responses in intake, respiration rates, and blood metabolites. The highest cottonseed diet significantly depressed intake of both dry matter and calculated net energy for lactation. Maximum dry matter from cottonseed eaten by an individual was 8.4 kg/d (average for 1 wk). Respiration rates declined parallel to intake. No evidence for gossypol toxicity was seen among data of 11 metabolites in blood.

Animal Feed↗
PubMed1984

Value of panendoscopy in determination of second primary cancer. A study of 451 cases of head and neck cancer.

A series of 451 consecutive patient records were reviewed. Of these, 43 had diagnoses of epidermoid carcinoma of the head and neck. Triple endoscopy, by flexible fiberoptic methods, was performed on all these patients and was critical in the determination of second primary carcinoma in eight patients. As panendoscopy shows no mortality and a low morbidity rate, it should be used in diagnosis of second primary tumors, despite a probable low percentage of second primary discovery; long-term patient survival demands use of all available resources in such diagnoses.

Bronchoscopy↗
PubMed1984

The influence of milk diet, grain diet, and method of dosing on lead toxicity in young calves.

Twenty 2- to 3-week-old calves were fed a milk diet or a mixture of grain and hay. After acclimatization, all calves were dosed po with lead acetate for 7 days, either in solution via a nursing bottle or in a gelatin capsule. At the end of the treatment period, 6 of 10 calves fed milk were either dead or showed multiple signs of Pb poisoning. All calves fed grain and hay appeared normal. Tissue Pb was significantly higher in calves on a milk diet (p less than 0.05) compared to tissue from calves on a grain and hay diet. No significant differences wee found when dosing methods wee compared. These data clearly show that diet but not dosing methods greatly influenced the absorption and tissue distribution of Pb in calves. delta-Aminolevulinic acid dehydratase (ALAD) activity in blood dropped to approximately 20% of pre-Pb exposure concentrations within 24 hr after the initial dose of Pb and remained at this concentration despite continued Pb administration. Blood Pb concentrations indicate that, in this model, the Pb enters the blood rapidly and retention is prolonged. The calf model warrants further studies on absorption and metabolism.

Animal Feed↗
PubMed1984

Adaptation in the function of pharyngeal constrictor muscles.

The palatopharyngeus and pharyngeal constrictor muscles were studied by electromyography (EMG) and by direct observation with a flexible fiberoptic scope in the anesthetized as well as in the alert rhesus monkey. The muscles were monitored to determine the change in their discharge with nasal obstruction, head posture, head extension, and swallowing. The results indicated that certain regions of the middle and inferior pharyngeal constrictors never discharged during deglutition. Extending the head could induce a tonic discharge in fibers of the middle pharyngeal constrictor for the duration of head extension. Placement of water in the hypopharynx not only induced a sustained laryngospasm but also a tonic discharge in the select fibers of the superior and middle pharyngeal constrictors. Changing from a supine to an upright posture, or obstructing the nasal cavity, could induce a rhythmic discharge. These studies indicate that there are functional components of fibers within each of the anatomically recognized pharyngeal constrictors.

Airway Obstruction↗
PubMed1984

Effects of dietary sodium bicarbonate and calcium chloride on physiological responses of lactating dairy cows in hot weather.

Twenty-four lactating cows were assigned randomly to three treatments to evaluate responses to large differences of dietary sodium and chloride. Treatments were corn-cottonseed meal-corn silage based complete rations with either: 1) .23% sodium chloride (control), 2) control plus 2.28% calcium chloride, or 3) control plus 1.70% sodium bicarbonate. Treatment effects were significant for urine pH (7.96, 5.41, 8.18), blood pH (7.50, 7.39, 7.49), partial pressure of oxygen (91.2, 99.4, 86.3 mm Hg), partial pressure of carbon dioxide (34.60, 30.57, 32.98 mm Hg), bicarbonate (26.20, 18.06, 24.64 meq/liter), total carbon dioxide (27.51, 19.18, 25.88 mM/liter), base excess (4.50, -4.31, 3.13 meq/liter), plasma chloride (93.4, 102.8, 95.7 meq/liter), serum potassium (3.26, 4.24, 4.14 meq/liter), and inorganic phosphorus (7.11, 5.61, 6.80 mg/100 ml). Blood glucose (45.1, 43.0, 55.5 mg/dl) and blood urea nitrogen (11.8, 8.7, 11.9 mg/dl) exhibited treatment effects. Respiration rates, 84.8, 61.8, 89.9 per min, and body temperatures, 39.7, 39.0, and 40.0 degrees C were significantly different. Lower intake of the high chloride diet and higher intake of the bicarbonate diet were probably responsible for some of the effects. Dietary electrolytes should receive attention in formulation because acid-base status of the animal is determined, in part, by ionic concentration and balance of the diet.

Animals↗
PubMed1984

Effect of monensin on the morphology of mitochondria in rodent and equine striated muscle.

Heart, diaphragm, and rear limb muscle from ponies and rats treated with monensin were examined by light and electron microscopy. In both species, mitochondrial aberrations were observed in selected muscle cells. The aberrations consisted of loss of matrix substance (vacuolization) usually accompanied by swelling. Vacuolated mitochondria were characterized by an almost total loss of matrix substance with retention of the rudimentary cristae form. In ponies, most vacuolated mitochondria were observed in heart muscle though some also were found in the diaphragm. In rats, most vacuolated mitochondria were observed in the diaphragm with lesser numbers in rear limb and heart muscles. Red and white muscle fibers were identified in the rat diaphragm based upon fiber size and mitochondrial content. About equal numbers of vacuolated mitochondria were seen in each type of fiber when the total number of vacuolated mitochondria was small. However, when large numbers of mitochondria were vacuolated, the majority of affected mitochondria were seen in white muscle fibers. The form and distribution of vacuolated mitochondria seem sufficiently characteristic to be useful as indicators of monensin poisoning. Mitochondrial vacuolation may be a secondary effect of monensin toxicity since mitochondrial vacuolation does not occur either in cultured cells (plant or animal) or in root plants exposed directly to monensin.

Animals↗
PubMed1984

Clinical biochemical and hematologic values of the American Miniature Horse: reference values.

Sixteen clinical biochemical determinations and 13 hematologic measurements were performed on 49 healthy American Miniature Horses of mixed age and both sexes. Serum triiodothyronine and thyroxine values were also determined. Serum biochemical test results from American Miniature Horses compared favorably with values for full-sized horses, whereas differences in hematologic test results were noticed between American Miniature Horses and full-sized horses.

Animals↗
PubMed1983

Considerations of the structure of sesquiterpene lactones on biological activity: influence of the alpha-methylene-gamma-lactone moiety on mast cell degranulation.

Mast cell degranulation was quantitated by measuring percentage of histamine release, 45Ca2+ ion influx, or c-AMP cellular levels after stimulation with various concentrations of the sesquiterpene lactones hymenovin, helenalin, or tenulin. Hymenovin and helenalin, which contain an alpha-methylene-gamma-lactone moiety, produced extensive degranulation. Alkylation of the alpha-methylene-gamma-lactone group of these compounds with the amino acid cysteine before mast cell stimulation drastically reduced the capacity of these lactones to stimulate histamine release. Tenulin, which does not contain an alpha-methylene-gamma-lactone moiety, generally stimulated degranulation approximately equal to that of cysteine-treated hymenovin or helenalin. These data indicate that sesquiterpene lactones containing alpha-methylene-gamma-lactone are potent stimulators of mast cell degranulation. This phenomenon may have a significant role in the toxicity of some sesquiterpene lactones of poisonous plants when ingested by livestock.

Animals↗
PubMed1983

Phototoxic effect of Thamnosma texana (Dutchman's breeches) in sheep.

Oral exposure of sheep to the airdried, aerial portions of Thamnosma texana (Dutchman's breeches) resulted in severe photosensitization. Sheep fed the plant at 9 or 12 g/kg of body weight/day and held in direct sunlight exhibited signs of phototoxicosis within 24 to 48 hours. The clinical signs manifested were increased body temperature; photophobia; edema of the muzzle, ears, and vulva; keratoconjunctivitis with edema of the cornea; and exudative dermatitis of the skin of the ears, muzzle, and vulva. Lesser dosages of the plant produced similar effects after several days, except that corneal edema and opacity were not seen. Histopathologic studies indicated no hepatic lesions, consistent with primary photosensitization. The photosensitizing effects of T texana can be attributed to the presence of photosensitizing linear furocoumarins (psoralens) in the plant.

Animals↗
PubMed1982

High resolution CT with image reformation in maxillofacial pathology.

Twenty-four patients with maxillofacial pathology were examined with computed tomography (CT) using thin (1.5-5.0 mm) sections allowing computer reformation of images in multiple planes. Eight patients also had pluridirectional tomography. The patients included 14 with facial trauma, four with acute paranasal sinus infections, and six with suspected neoplasms. High resolution CT with reformations allowed thorough evaluation of facial trauma. Fracture sites were correctly identified, as were the relation of fragments to vital structures. The form of structural facial alteration was easily assessed, optimizing the presurgical plan for reconstruction. In addition, CT allowed simultaneous evaluation of associated brain injury. In acute infectious processes and neoplasms, CT defined the extent of involvement and directed the type of therapy. In both situations, accurate assessment of bony destruction permitted definitive planning for bony debridement in infection and helped in the differentiation of benign from malignant processes in neoplasia. Density determination also allowed differentiation of neoplastic soft tissue from inspissated mucus within obstructed sinuses. Experience suggests that CT can be the definitive imaging method in the diagnosis of complex maxillofacial pathology when sufficient evaluation is unavailable from plain films. It was superior to thin-section pluridirectional tomography in several instances.

Humans↗
PubMed1982

Airway obstruction in the pediatric patient.

In the newborn period and early infancy upper respiratory tract obstruction is commonly caused by congenital and neoplastic disorders, such as laryngomalacia, congenital subglottic stenosis, or brainstem anomalies. However, inflammatory causes of airway obstruction predominate in infancy and childhood. Laryngotracheal foreign bodies and trauma, on the other hand, have no age predilection. The diagnosis and therapy of airway obstruction in the pediatric patient are discussed.

Airway Obstruction↗