Veterinary Medicine Commons^™

Effects Of Methylxanthines On Newborn Rat Respiration, Craig Gatto

Masters Theses

Methylxanthines (MX), such as theophylline, are commonly used in the treatment of recurrent apnea due to their stimulant effects on the respiratory center. Structure-activity studies have demonstrated that substitution of alkyl groups on the 3-position of the xanthine nucleus results in increased bronchodilator potency, while substitution on the 1-position is important for adenosine antagonism and CNS stimulation. Three different alkylxanthines were studied to determine the structural requirements for respiratory stimulation. Respiratory rates and volumes were determined in 4- to 7-day-old rats using a volume displacement body plethysmograph. Measurements were made before and at 5 minute intervals after subcutaneous (s.c.) injection …

The Effects Of Xanthine And Adenosine Analogs On Rat Pup Diaphragmatic Contractility, Liam C. Farrell

Masters Theses

Methylxanthines are commonly used in the treatment of respiratory disorders such as asthma, apnea of prematurity and Cheyne-Stokes respiration. Recently, certain methylxanthines have been found to potentiate the contraction of the diaphragm and increase contraction strength of the fatigued diaphragm. The mechanism of action of the methylxanthines is unknown. Three theories have been proposed but each has its supportive and negative points. One theory is that methylxanthines inhibit cyclic AMP phosphodiesterase (PDE) which facilitates contraction by increasing cyclic AMP levels in the cell. Another theory is that methylxanthines antagonize adenosine, thus blocking the adenosine-induced inhibition of contraction. The third theory …

Observations On Relationships Between Limb Measurements And Mode Of Locomotion In Malaysian Turtles, Duayne Nyckel

Masters Theses

Twelve Genera (spanning three Families) of Malaysian Turtles were studied to determine whether bone lengths could be correlated to mode of locomotion. Ulna, humerus, tibia, femur, coracoid (among others) were measured and results were presented graphically. Five of the genera were observed singly in a large aquarium. Data were recorded on the amount of time each spent in different locomotor modes. Both limb length data and aquarium observations suggest that turtles can be grouped into three main locomotor habits (i.e. terrestrial walking, bottomwalking, and swimming). The terrestrial group includes the genera, Geochelone, Kinixys, and Gopherus. Bottomwalkers include …

The Effects Of Crowding On The Diurnal Ascorbic Acid Levels Of Albino Rats, Mary Jo Barr

Masters Theses

The adrenal physiology of the albino rat was studied through the measurement of adrenal ascorbic acid levels. A cyclic phenomenon was observed which follows the diel periodicity of the animal. Ascorbic acid values were found to be characteristically higher in males than in females. A similar difference was also seen in populations divided into young animals (body weight less than 175 grams) and old animals (body weight greater than 175 grams). Crowding, induced by manipulating the area of cage space per gram of body weight, was observed to be a definite stressor and caused the adrenal ascorbic acid levels to …

The Effects Of Acute Stress On Adrenal Ascorbic Acid Levels, Robert Joseph Collier

Masters Theses

The diurnal rhythm of adrenal ascorbic acid (DAR) displays an inverse relationship to the diurnal rhythm of circulating levels of plasma corticosteroids. Alloxan monohydrate, 175 mg/kg body weight was given subcutaneously to albino rats to determine the effect of the diabetic state on the DAR. A total of 200 female albino rats were divided into two study groups. Study Group I was composed of 150 animals divided into populations of 15, each including 3 controls. Study Group II was composed of populations of 5, each group containing all controls or all alloxinated rats. The populations of 15 were sacrificed at …

Seasonal Variation In The Tubular And Interstitial Areas Of The Testes In Sternotherus Odoratus L., Robert Hans Spaet

Masters Theses

Seasonal changes within the tubular and interstitial areas of the testes in Sternotherus odoratus are investigated, histologically and histochemically. Forty specimens were collected in Illinois, Tennessee and Louisiana between May, 1969 and August, 1972.

Many of the histological and macroscopic observations made by Risley (1938) on the spermatogenic cycle of S. odoratus in Michigan are confirmed. Contrary to his findings, fluctuations in interstitial cell nuclear diameters are observed during spermatogenesis. Greatest diameters coincide with what Risley has considered " . . . period of most active breeding." Sertoli cell nuclear diameters undergo similar fluctuations being greatest during spring breeding and …

A Study Of Thoracic Skeletomusculature In Peracarida (Crustacea), Donna R. Gill

Masters Theses

Two species of peracarid malacostracans, a mysid, Neomysis americana, and an oniscid isopod, Trachelipus cf. rathkei, were used to study the skeletomusculature system. Serial sections, whole mounts, and gross dissections were made. Coxal promotors and remotors and basal adductors and abductors were the muscle groups examined.

The promotor and remotor muscles of N. americana were found to be numerous, well developed, taking origin primarily from the dorsal thoracic wall, and extending nearly ventrally to insert in the coxa; the adductor muscle and two abductor muscles are weakly developed. The coxa in T. cf. rathkei is incorporated completely …

The Comparative Morphology Of The Female Gonads Of Two Members Of The Nematode Order Tylenchida, Owen G. Coker

Masters Theses

No abstract provided.

A Survey Of The Incidence Of Salmonellosis In Three Groups Of Wild Animals, James T. Heiberger

Masters Theses

No abstract provided.

A Study Of The Digestive System In The Sparrow (Passer Domesticus), Henry Joseph Wisniewski

Bachelors’ Theses

The digestive tube proper of the Sparrow beings with the Oesophagus. This is a soft tubular organ which serves to convey food rapidly from the pharynx to the stomach. It extends along the median ventral margin of the neck lying dorsal to or to one side of the trachea. Posteriorly, at the base of the neck and shortly in front of the sternum it broadens slightly and gives rise to a dilated region of the oesophagus, namely the Crop, "whose secretion serves to moisten the food or even to initiate digestion." In larger birds as in the pigeon, the crop …

The Parasitic Worms Of Man And The Domestic Animals, Henry B. Ward

Studies from the University of Nebraska Zoological Laboratory

This article has been written for the general information of those engaged either on a large or on a small scale in stock raising in our own state particularly, and, while not intended to be a complete treatise on the subject, it includes references to those parasites which seem to be the most important or most likely to be found within our borders. The parasites of cattle, sheep, horse, hog, dog, cat, and man, which have many species in common, form the subject of this paper. The parasites of domestic fowl are, however, quite different from those considered here and …

Report Of The Zoologist, Henry B. Ward

Studies from the University of Nebraska Zoological Laboratory

In the report of last year was given a full summary of the present state of our knowledge concerning the parasites of man and the domestic animals. It is the intention of the following pages to review the parasitic fauna of the state of Nebraska so far as it is definitely determined, and also to include a list of some species reported but not accurately identified. The second section of this report presents a brief description of some important parasites not included in the group of worms, and hence not mentioned in last year's report. I shall omit all parasites, …