Fading kitten syndrome and neonatal isoerythrolysis.

Fading kitten syndrome includes noninfectious and infectious causes for neonatal death (birth to weaning age). Noninfectious causes are mostly responsible for mortality in the first week of life and include congenital disorders, low birth weights, trauma, malnutrition, environmental causes, and neonatal isoerythroylsis. Infectious causes are more prevalent at 3-4 weeks of age. This article discusses the causes, clinical signs, and management of fading kitten syndrome.

Vertebral scale system to measure canine heart size in radiographs.

A method for measuring canine heart size in radiographs was developed on the basis that there is a good correlation between heart size and body length regardless of the conformation of the thorax. The lengths of the long and short axes of the heart of 100 clinically normal dogs were determined with calipers, and the dimensions were scaled against the length of vertebrae dorsal to the heart beginning with T4. The sum of the long and short axes of the heart expressed as vertebral heart size was 9.7 +/- 0.5 vertebrae. The differences between dogs with a wide or deep thorax, males and females, and right or left lateral recumbency were not significant. The caudal vena cava was 0.75 vertebrae +/- 0.13 in comparison to the length of the vertebra over the tracheal bifurcation.

Detection of platelet-bound and serum platelet-bindable antibodies for diagnosis of idiopathic thrombocytopenic purpura in dogs.

The sensitivity and specificity of 2 antibody tests for diagnosis of idiopathic thrombocytopenic purpura (ITP) in dogs were investigated prospectively. An ELISA to detect antibodies bound to the surface of platelets from affected dogs (direct test) was performed in 34 dogs with a clinical diagnosis of ITP and in 21 dogs with thrombocytopenia attributable to other causes. An ELISA to detect platelet-bindable antibodies in serum from affected dogs (indirect test) was performed in 32 dogs with ITP and in 15 dogs with other causes of thrombocytopenia. The direct test was positive in 32 of 34 dogs with ITP (sensitivity, 94%) and negative in 13 of 21 dogs with other causes of thrombocytopenia (specificity, 62%). Positive direct test results were obtained in 2 dogs with systemic lupus erythematosus, and in 1 dog each with concurrent Ehrlichia canis and Babesia canis infections, dirofilariasis, myelodysplasia, disseminated intravascular coagulation (of unknown cause), and thrombocytopenia subsequent to administration of trimethoprim/sulfadiazine, as well as in 1 dog with thrombocytopenia 14 days after a whole blood transfusion. The indirect test had positive results in 11 of 32 dogs with ITP (sensitivity, 34%) and negative results in 12 of 15 dogs with other causes of thrombocytopenia (specificity, 80%). Positive indirect test results were obtained in 1 dog each with systemic lupus erythematosus, concurrent E canis and B canis infections, and thrombocytopenia subsequent to administration of trimethoprim/sulfadiazine. Detection of platelet-bound antibodies was more sensitive than detection of serum-platelet bindable antibodies in confirming a diagnosis of ITP in dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Alloantibodies against A and B blood types in cats.

This study characterizes the naturally occurring feline alloantibodies against A and B blood type. All examined type-A and type-B cats had naturally occurring antibodies against erythrocytes of the opposite blood type. In order to determine the class of immunoglobulins, sera from cats were analyzed using incubation with 2-mercaptoethanol (2-ME), immunoprecipitation, and gel filtration. Type-A cats had weak agglutinins of the IgM class and weak hemolysins which consisted of approximately equal parts of IgG and IgM class. Type-B cats had strong hemagglutinins and hemolysins mostly of the IgM class. Colostral antibodies were detectable in newborns as early as 4 h after birth and their own alloantibody production started at 6-8 weeks of age. The presence of naturally occurring alloantibodies, in particular the anti-A alloantibodies, renders cats susceptible to clinical incompatibility reactions.

Outpatient blood donor program.

An outpatient donor program using pets owned by employees or clients is a practical and cost-efficient means of obtaining blood for transfusion. Donors can have blood typed and be screened for certain diseases, and blood can be drawn at a convenient time. Components can be prepared and stored. Although such a program requires a commitment to assemble reliable volunteers, the results is a team effort that can be rewarding and assures an adequate blood supply.

Transfusion of type-A and type-B blood to cats.

Although nearly all domestic shorthair and longhair cats have type-A blood (greater than 99%), the frequency of blood type B in various feline breeds ranges from 0 to 59%. All blood-type-B cats have strong natural alloantibodies, predominantly of the IgM class, whereas blood-type-A cats have low alloantibody titers of the IgG and IgM classes. We therefore studied the efficacy and safety of transfusing 20 ml of matched and mismatched 14C-potassium cyanate-labeled blood to cats. In autologous and allogeneic matched transfusions of blood-type-A and type-B cats, the half-life of labeled erythrocytes proved to be similar (29 to 39 days). In contrast, type-B erythrocytes transfused into 5 blood-type-A cats had a mean (+/- SD) half-life of only 2.1 +/- 0.2 days and induced minor transfusion reactions. Half of the type-A blood given to 4 blood-type-B cats was destroyed within minutes to 6 hours (mean +/- SD = 1.3 +/- 2.3 hours), depending on the alloantibody titer. After 1 day, none of the labeled erythrocytes were detected. Mismatched transfusions in blood-type-B cats caused marked transient reactions including systemic anaphylactic signs (hypotension, bradycardia, apnea, urination, defecation, vomiting, and severe neurologic depression) and hemolytic signs (hemoglobinemia and pigmenturia) associated with severe reduction in plasma alloantibody titer and complement activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency and inheritance of A and B blood types in feline breeds of the United States.

Using a simple hemagglutination assay to determine A and B blood types, we surveyed 1,072 domestic short- and longhair (DSH/DLH) cats and 1,100 purebred cats in the United States. Data from 234 matings with 552 offspring were consistent with the hypothesis that feline blood types A and B are due to the action of two different alleles at the same gene locus and that A is completely dominant over B. Neither an AB nor an O type cat was encountered. No type B cats were found in the Siamese and related breeds or in American Shorthair and Norwegian Forest cats. Among the breeds with type B blood, the proportion was lowest in DSH/DLH cats (0.0028) and variably higher in Abyssinian, Birman, British Shorthair, Devon Rex, Himalayan, Persian, Scottish Fold, and Somali, ranging from 0.15 to 0.59. Since all type B cats have strong, naturally occurring anti-A alloantibodies, fatal neonatal isoerythrolyses occur in type A offspring of type B mothers bred to type A males. The gene frequency of the B allele and the proportion of mating at risk of neonatal isoerythrolysis were estimated in a number of breeds. In most breeds, the frequency of the B allele was less than 0.5. Since the kittens at risk for neonatal isoerythrolysis always have the genotype AB, there is constant natural selection against heterozygotes. Heterozygote disadvantage in the cat AB system represents an unusual form of negative selection, similar to that in Rh blood group incompatibility in humans.

1,2-Dimethylhydrazine-induced methylation of DNA bases in various rat organs and the effect of pretreatment with disulfiram.

The extent and persistence of methylated purines were determined in DNA of various rat organs following a single s.c. injection of 1,2-di[14C]methylhydrazine. Maximum alkylation of purine bases occurred within 12 hr, with highest concentrations in liver, followed by colon, ileum, and kidney. Over a period of 3 days, O6-methylguanine was removed much more slowly from colon, the principal target organ for carcinogenesis, than from ileum or liver DNA. Dietary pretreatment of rats with disulfiram is known to prevent 1,2-dimethylhydrazine-induced colon carcinogenesis and was found to reduce DNA alkylation to less than 1% of that detected in animals treated with 1,2- di[14C]methylhydrazine alone.

DNA repair as regulatory factor in the organotropy of alkylating carcinogens.

Monofunctional alkylating agents which react predominantly at nitrogen atoms in DNA bases (e.g. alkyl methanesulphonates, dialkylsulfates) are generally weak carcinogens whereas compounds which lead extensively to oxygen alkylation (e.g. alkylnitrosoureas, dialkylnitrosamines, dialkyl-aryltriazenes) often exhibit a strong carcinogenic activity. O6-Alkylation of guanine is a promutagenic DNA modification possibly involved in the initiation of malignant transformation. O6-Alkylguanine can be enzymically excised and in the rat the induction of neural, renal and colonic tumors by alkylnitrosoureas, 3,3-dimethyll-phenyltriazene, dimethylnitrosamine and 1,2-dimethylhydrazine correlates with an excision repair deficiency in the target tissue. However, species and strain differences in the response to these carcinogens are not paralleled by differences in the excision repair capacity for O6-alkylguanine. Preliminary data suggest that in rat liver there is an inducible enzyme for the removal of O6-alkylguanine from DNA.

Reaction of 7,12-dimethylbenz(a)anthracene with DNA of fetal and maternal rat tissues in vivo.

Pregnant BD-IX rats (21st day of gestation) received a single IV injection (15 mg/kg) of tritiated 7,12-dimethylbenz(a)anthracene (DMBA), A DOSE KNOWN TO INduce a high incidence of nervous-system tumors in the offspring. The animals were killed 12 h later and hydrocarbon-deoxyribonucleoside products from DNA of maternal and fetal tissues were separated on Sephadex LH-20 columns eluted with a 20-100% methanol gradient. Concentrations of the major DMBA-DNA adduct varied considerably, with highest values in maternal intestine, liverand lung, followed by spleen, kidney and brain. In fetal intestine and liver, concentrations were 34% and 16% lower than in the respective maternal organs whereas the reaction with cerebral DNA was 2 1/2 times higher in fetuses than in the pregnant mother. This indicates that there is no significant placental barrier to DMBA or DMBA metabolites involved in DNA binding and that rat fetuses participate in the metabolic formation of the ultimate carcinogen.

Selective induction of melanomas in gerbils (Meriones unguiculatus) following postnatal administration of N-ethyl-N-nitrosourea.

Following a single ip injection (50 mg/kg) of N-ethyl-N-nitrosourea (ENU) on postnatal day 7 or 20, 9 of 21 gerbils (43%) developed a total of 15 cutaneous melanomas. The mean survival time of tumor-bearing animals was 909 +/- 212 (SD) days. Neoplasms were preferentially located at sites with little hair and with high content of pigment cells (feet, ears, tail, or snout). Histologic studies on newborn gerbils indicated that ENU-induced malignant transformation occurred in differentiated melanocytes rather than in precursor cells of the neural crest.