Effect of an interfering substance on determination of potassium by ion-specific potentiometry in animal urine.

Analytical characteristics of photometry and ion-specific potentiometry for urine from sheep, horses, cows, dogs, and cats were determined, using solutions of sodium and potassium chloride. The performance of both methods were acceptable, but the ion-specific potentiometer (in the mode for urine analysis) was superior in terms of linearity of response and correlation between actual vs measured concentrations. Coefficients of variation of either method for repeated analyses of various concentrations of sodium and potassium were always less than 2.5%. The measurement of sodium concentration in urine samples correlated well between both methods for samples from sheep, horses, cows, dogs, and cats. In contrast, measurement of potassium concentrations in urine samples from sheep, horses, cows, and cats was underestimated consistently by ion-specific potentiometry. The magnitude of the apparent error was variable between species and was often increased with greater urine potassium concentrations. These phenomena were not seen in urine samples from dogs. Sequential dilution of urine samples from sheep before analysis reduced the magnitude of the error observed by ion-specific potentiometry. Seemingly, an equilibrium process existed in which potassium was bound by an anionic or zwitterionic chemical and was sequestered from interaction with the ion-specific electrode. Ultrafiltration experiments indicated the putative potassium chelator was a low molecular weight compound.

Lead-induced toxicosis in two domestic rabbits.

Lead toxicosis developed in 2 pet rabbits. Both rabbits had decreased appetite or anorexia; also, one had mild anemia and one had pleural effusion. Treatment with the calcium chelate of ethylenediaminetetraacetic acid was effective in both rabbits. The rabbit's propensity for gnawing may result in lead toxicosis, and may be seen more frequently as rabbits become more popular as pets.

Pancreatic carcinoma in a cockatiel.

A female cockatiel was examined because of abdominal distention, decreased appetite, and weight loss. Although abdominocentesis, bacteriologic culture, radiography, and ultrasonography were performed, the diagnosis of pancreatic carcinoma was obtained only after exploratory laparotomy and histologic examination. The resected abdominal mass was pancreatic carcinoma. The bird survived for 56 days after surgery. Necropsy confirmed abdominal metastatic pancreatic carcinoma.

Blood lead concentrations in rabbits.

Blood lead concentrations in 68 healthy rabbits from laboratory (n = 15), meat production (n = 45), and home environments (n = 8) were determined. The median blood lead concentration of this heterogeneous population was 8 micrograms/dl (range = 2 to 27 micrograms/dl).

Translocations, the predominant cause of total sterility in sons of mice treated with mutagens.

Histological and cytological analyses of the testes were carried out in 42 sterile sons of males treated in the spermatozoal or spermatid stage with 250 mg/kg ethyl methanesulfonate (EMS) alone or after prefeeding with butylated hydroxytoluene (BHT); or treated with 200 R X-rays. Of the 42 sterile males, 17 had some mature spermatids, nine were blocked at diakinesis, 15 were blocked in pachytene, and one lacked spermatogenic cells altogether, having Sertoli cells only. Mitotic (spermatogonial) metaphases could therefore be analyzed in 41 of the males and meiotic configurations in 26.-(1) None of the males showed abnormalities in chromosome number, such as monosomy, trisomy, or mosaicism for either of these conditions. Certain classes of chromosome abnormalities that have been found associated with male sterility in other investigations, namely trisomies, XXY's, and X-autosome translocations, are not expected from treatment of 19A + Y cells when F(1) males are studied. (2) A very high percentage of the sterile males carried translocations. Direct meiotic evidence for this was found in 22 of the animals. In addition, 11 of the 16 that were blocked (or virtually blocked) in pachytene, and thus could be analyzed in mitosis only, consistently showed one abnormally short chromosome (or, one short plus one long), which presumably had resulted from unequal exchange (or sizable deficiency). Of the meiotically detected translocation males, 1 carried a T(A;Y), 17 had single autosomal translocations, and 4 had multiple autosomal rearrangements involving three, four, four, and six breaks, respectively. In addition, three males showed failure of X-Y pairing. (3) Translocations that cause sterility, rather than partial sterility, in males appear to be those in which at least one of the breaks occurs close to one end of a chromosome. The mitotic and meiotic evidences for this were found to be correlated. (4) It is proposed that many cases of induced F(1) male sterility may be the result of position effects produced when paracentromeric regions are translocated to euchromatic regions of certain other chromosomes. Since many translocations that produce partial sterility in the female cause complete sterility in the male, the male must be assumed to be more susceptible to disturbances of fertility by the postulated mechanism. (5) There is evidence that EMS, especially in the lower dose range, more often breaks chromosomes near one of their ends than does X-irradiation.