Effect of o,p'DDD therapy on endogenous ACTH concentrations in dogs with hypophysis-dependent hyperadrenocorticism

The effect of o,p'DDD therapy on the endogenous plasma ACTH concentration was evaluated in 15 dogs with hypophysis-dependent hyperadrenocorticism. Adequate control of hyperadrenocorticism with o,p'DDD was based on the reduction of water consumption to within the normal range, disappearance of clinical signs of lethargy, weakness, alopecia, thin skin, or pendulous abdomen, and an increase in blood cortisol below the normal range after exogenous ACTH administration. Endogenous ACTH concentrations were determined for each dog after the disease was controlled and while they were given o,p'DDD on a maintenance schedule. Endogenous ACTH concentrations increased in 14 of 15 dogs after o,p'DDD therapy, indicating a lack of suppressive effects of o,p'DDD on hypophysis ACTH secreting cells.

Thyrotropin-releasing hormone stimulation testing in healthy dogs

Serum triiodothyronine (T3) and thyroxine (T4) concentrations were determined after IV administration of 200 micrograms of thyrotropin-releasing hormone (TRH) to 10 healthy euthyroid dogs. Significant (P less than 0.05) changes were not found in the T3 concentration throughout an 8-hour sampling interval. All dogs had a significant increase (P less than 0.05) in the T4 concentration at 4, 5, 6, 7, and 8 hours after TRH administration. The largest increase in the serum T4 concentration occurred 4 hours after TRH injection. From 4 to 8 hours after TRH administration, the mean increase above basal T4 concentrations was 13.9 +/- 5.4 ng/ml.

Oligomeric regulation of the later reaction steps of the sarcoplasmic reticulum calcium ATPase

The phosphorylated intermediate of the sarcoplasmic reticulum Ca2+ ATPase (EP) was formed from [gamma-32P] ATP, and its decomposition was monitored by chasing with either ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) or an excess amount of [gamma-31P]ATP. Chasing in the initial phase of E32P formation leads to monophasic and rapid decomposition, whereas chasing after the maximal level of E32P has been reached leads to biphasic decomposition. If a portion of EPtotal is formed from [gamma-31P]ATP (E31P) and the rest from [gamma-32P]ATP (E32P), decomposition of the later portion (E32P) is roughly monophasic and the rate of decomposition is about the same as that of the slow phase of the biphasic decomposition. Initiation of the EP reaction by concurrent addition of [gamma-32P]ATP and EGTA, conditions that permit the selective monitoring of the EP reaction via one of the subunits of the putative dimer (Ikemoto, N., Garcia, A. M., Kurobe, Y., and Scott, T. L. (1981) J. Biol. Chem. 256, 8593-8601) leads to monophasic decomposition at a rate comparable with the fast phase of biphasic decomposition. The kinetics of biphasic EP decomposition is reversibly affected by the nonionic detergent ethylene glycol monoether and the cleavable cross-linker dithiobissuccinimidyl propionate, both of which presumably affect subunit-subunit interactions. The results suggest that the biphasic EP decomposition is due to sequential liberation of Pi from different subunits (EI and EII) forming an oligomer as shown in the following model.

Lymphocytic-plasmacytic colitis in the cat

Lymphocytic-plasmacytic colitis was diagnosed in 6 cats. Owners sought veterinary care because of semiformed -to-liquid feces, tenesmus , fresh blood and/or mucus in the feces, or increased frequency of defecation in their cats. Lymphocytic, plasmacytic infiltration in the colonic lamina propria was found on colon biopsies. Clinical signs resolved in all 6 cats after dietary management, utilizing lamb and rice, horsemeat , or a feline prescription diet. Clinical improvement also occurred in 1 cat following sulfasalazine therapy.

Reversible control of oligomeric interaction of the sarcoplasmic reticulum calcium ATPase with the use of a cleavable cross-linking agent

Reversible cross-linking with a cleavable homobifunctional reagent, dithiobissuccinimidyl propionate, of the Ca2+ ATPase polypeptides of fragmented sarcoplasmic reticulum produces oligomers in the range of 2 to 4 X 100,000 Da (cf. Louis, C. F., and Holroyd, J. A., (1979) Biochim. Biophys. Acta 535, 222-232). The presence of millimolar ATP during the dithiobissuccinimidyl propionate reaction protects the enzyme from inactivation without affecting cross-linking. In the presence of both ATP (e.g. 1 mM) and Ca2+ (e.g. 0.21 mM), there is no inhibition of phosphoenzyme (EP) formation and presteady state Ca2+ translocation, whereas Ca2+-induced conformational changes of the enzyme, and EP decomposition are inhibited. Cleavage of the S-S bond of the cross-links reverses the inhibition of conformational changes but has little effect on the inhibited EP decomposition. This indicates that the inhibition of conformational changes is due to cross-linking, while that of EP decomposition is due to the chemical modification as such. If [Ca2+] is low during the dithiobissuccinimidyl propionate reaction (e.g. pCa 7.6), the Ca2+-induced conformational changes of the enzyme, EP formation, presteady state Ca2+ translocation, and EP decomposition are inhibited, even in the presence of ATP. Cleavage of the cross-links reverses the inhibition of conformational changes and EP formation, but again has little effect on EP decomposition. Thus, the primary effect of cross-linking at high and low [Ca2+] is the inhibition of the Ca2+-induced conformational change, suggesting that extensive interaction of subunits is involved in this reaction step. The fact that EP formation and presteady state Ca2+ translocation are inhibited by cross-linking carried out at low but not at high [Ca2+] suggests that cross-linking takes place at different regions of the enzyme molecule at different [Ca2+].

Treatment of canine pyometra and endometritis with prostaglandin F2 alpha

Seventeen bitches with pyometra or postpartum endometritis were treated with prostaglandin F2 alpha. Response to the treatment included cessation of uterine discharge, decrease in uterine diameter, reduction in plasma progesterone concentration, and return of a normal leukogram. Treatment of 14 bitches was successful, and 13 of these bitches subsequently experienced estrus. Of those 13 bitches, 11 were bred and 9 became pregnant. In 2 bitches, pyometra developed again, within 6 weeks of the following estrus, illustrating that bitches so affected are susceptible to recurrence of the disease. Of 4 bitches with closed cervix, one failed to respond to treatment, and two bitches with closed cervix required ovariohysterectomy shortly after instituting treatment.

Insulin-induced hyperglycemia in diabetic dogs

Insulin-induced hyperglycemia was diagnosed in 8 dogs with diabetes mellitus. Owners sought veterinary care because of polydipsia, polyuria, polyphagia, persistent morning glycosuria, or seizures in their dogs. These abnormalities had persisted despite increasing the dosage of insulin. Insulin-induced posthypoglycemic hyperglycemia was diagnosed by determining blood glucose concentrations every 2 hours during a 24-hour period, beginning at 8 A.M. Wide fluctuations in the blood glucose concentration were reduced by decreasing the daily insulin dose. The signs observed by the owners disappeared after the insulin dose was reduced.

Intrathecal methotrexate-induced neurotoxicities

The pharmacokinetics, therapeutic index, neurotoxicities, methods of administration, and dosages of intrathecal methotrexate are reviewed. The intrathecal administration of methotrexate can provide therapeutic concentrations in the cerebrospinal fluid (CSF) without the use of high-dose intravenous methotrexate. Major neurologic complications have been reported to occur in 3--40% of patients following intrathecal methotrexate. The development of neurotoxicity is related to dose, concentration of methotrexate in the CSF, age of the patient, anatomical and physiological abnormalities in the CNS, type of dilutional vehicle, intracranial radiation, and intravenous methotrexate. Substantial evidence is lacking that chemical preservatives and methotrexate breakdown products are risk factors. The use of intrathecal methotrexate is a reasonably safe and effective chemotherapeutic modality when proper administrative techniques are observed.

Neuropsychological test performances of paranoid schizophrenic and brain-damaged patients

Predicted that simple tests that require attention and motor speed would be able to differentiate paranoid schizophrenics from brain-damaged patients better than more complex, problem-solving neuropsychological tests. The strategy was to improve discrimination between schizophrenic and brain-damaged patients by selecting a schizophrenic subgroup with a recognized cognitive strong point. Fourteen organic, 14 paranoid schizophrenic, and 14 nonpsychotic psychiatric patients matched for sex, education, and IQ were tested. As predicted, the attention and speed measures differentiated the brain-damaged and paranoid groups, while the four more complex measures from the Halstead-Reitan Battery did not separate the groups. There were no significant differences between the two psychiatric groups.

Multilayer film elements for clinical analysis: applications to representative chemical determinations

Using the general concept of a dry multilayer analytical element, we can change chemical procedures and configurations to assay several blood components. In the assay of serum urea nitrogen, urease in the reagent layer catalyzes the hydrolysis of urea. A semipermeable membrane excludes aqueous base, but allows ammonia to diffuse to an underlying indicator layer. For the amylase determination, the enzyme hydrolyzes a dyed-starch substrate coated on top of the spreading layer; this produces small fragments, which diffuse to a registration layer. The increase of absorbance at 540 nm is correlated with amylase activity. Bilirubin complexes with a cationic polymer at the interface between the spreading and reagent layers. The direct reading at 460 nm allows determination of total bilirubin in the range 1 to 500 mg/liter. Tirglycerides are hydrolyzed in the spreading layer, and the resulting soluble glycerol readily diffuses into the reagent layer, where it is phosphorylated and subsequently oxidized by glycerophosphate oxidase to yield dihydroxyacetone phosphate and hydrogen peroxide. Peroxidase catalyzes production of a color commensurate with the hydrogen peroxide produced.

Multilayer film elements for clinical analysis: applications to representative chemical determinations

Using the general concept of a dry multilayer analytical element, we can change chemical procedures and configurations to assay several blood components. In the assay of serum urea nitrogen, urease in the reagent layer catalyzes the hydrolysis of urea. A semipermeable membrane excludes aqueous base, but allows ammonia to diffuse to an underlying indicator layer. For the amylase determination, the enzyme hydrolyzes a dyed-starch substrate coated on top of the spreading layer; this produces small fragments, which diffuse to a registration layer. The increase of absorbance at 540 nm is correlated with amylase activity. Bilirubin complexes with a cationic polymer at the interface between the spreading and reagent layers. The direct reading at 460 nm allows determination of total bilirubin in the range 1 to 500 mg/liter. Tirglycerides are hydrolyzed in the spreading layer, and the resulting soluble glycerol readily diffuses into the reagent layer, where it is phosphorylated and subsequently oxidized by glycerophosphate oxidase to yield dihydroxyacetone phosphate and hydrogen peroxide. Peroxidase catalyzes production of a color commensurate with the hydrogen peroxide produced.