Evidence of functional lymphocytes in some (leaky) scid mice.

Although the majority of severe combined immune deficiency (scid) mice lack functional lymphocytes, some (2-23%) appear to develop a limited number of B and T cells between 3 and 9 mo old. Most of these leaky scid mice were shown to contain very few clones (less than or equal to 3) of Ig-producing plasmacytes. Clonal progeny were distributed unevenly in the lymphatic tissues and appeared as discrete plasmacytic foci. In many cases, individual clones persisted for several months and produced abnormally high concentrations of Ig that included multiple isotypes. Functional T cells were inferred from the ability of leaky mice to reject allogeneic skin grafts, a T cell-dependent reaction. Interestingly, approximately 40% of leaky mice developed thymic lymphomas. In other respects, leaky mice resembled regular scid mice; e.g., their splenic cells failed to express common lymphocyte antigens (Ly-5[B220], Ly-1) and to proliferate in response to lymphocyte mitogens. Histologically, their lymphoid tissues retained the same general pattern of severe lymphocytic deficiency as scid mice.

Growth of human normal and neoplastic mammary tissues in the cleared mammary fat pad of the nude mouse.

Dysplastic and malignant human breast tissues were grown successfully in the cleared mammary fat pads (CFP) of nude mice. The mammary fat pads were cleared while the mice were in a germfree isolator. Prepared mice were removed fron the germfree enviornment to facilitate transplantation of the human mammary tissue into their CFP and subsequently were maintained in sterile laminar flow racks.

Chronic toxicity of methotrexate in rats: partial to complete projection of the liver by choline: Brief communication.

Methotrexate (MTX) inhibits the enzyme dihydrofolate reductase, which in turn limits the body's ability to perform transmethylation reactions. This study examined the hypothesis that the consequent deficiency of an important methylated compound, choline, may have contributed to the MTX-induced fatty change in the liver of W rats. Groups of rats were given MTX alone or MTX plus choline in varying dose combinations. All groups but one receiving the combined treatment showed a significantly lower triglyceride concentration in their livers and much less visible hepatocytic fat on histologic examination than did those given MTX alone. The protective effect of choline on the liver was dose related, the unaffected group having received a very small amount. Growth rate, survival, and hematopoietic depression due to MTX were unaltered by choline administration.

Hepatotoxicity in Wistar rats following chronic methotrexate administration: a model of human reaction.

The effects of ip administration of methotrexate (MTX) on 3-month-old male Wistar rats were studied. We administered log doses from 125 to 2,000 mug/kg, five times per week for as long as 24 months. The massive doses were promptly lethal, and most rats receiving 500 mug or more/kg died within a few weeks. Severe hematopolietic depression and ulcerative gastrointestinal lesions were observed. Truly chronic intoxication was achieved with the lesser doses. Rats in this category developed serious liver damage, namely, varying degrees of fatty metamorphosis, necrosis, atrophy of hepatic cords, and fibrosis. Hematopoietic depletion occurred in the spleen and bone marrow. Hemosiderosis was prominent in the spleen and liver. Pulmonary lesions--chiefly emphysema, occasionally fibrosis--were found less consistently. These studies demonstrated the ability of MTX to induce lesions, most consistently hepatic, in the Wistar rat, and thus have provided an animal model to evaluate protective measures.

Influence of regenerative capacity and innervation on oncogenesis in the adult frog (Rana pipiens).

Twenty-two sarcomas were induced in 19 adult frogs (Rana pipiens) treated with 3-methylcholanthrene pellets. Thirteen of these tumors arose first in a denervated forelimb, and only 2 arose first in normal or nerve-supplemented control forelimbs (P = 0.004). The remaining tumors developed either as a second tumor in a tumor-bearing frog or in hindlimbs. The critical role of innervation in regenerative capacity suggests that the predilection to tumor formation in the denervated limbs may have resulted from their lessened regenerative capacity.

Persistence of precursor cells of squamous metaplasia in preneoplastic mammary outgrowth lines from mice.

The preneoplastic state is without apparent effect on the induction or prevention of epidermidalization in transplanted mammary outgrowth lines. Development of squamous metaplasia and differentiation (keratinization) were induced in organ cultures of three hyperplastic alveolar and ductular mammary outgrowth lines (D1, MH5, and MH9) that had been extensively passaged in gland-free mammary fat pads of BALB/c virgin mice. The induction was elicited by the mixture of dibutyryl cyclic AMP (0.1 mM), prostaglandins E1, E2, and B1 (each 5 micrograms/ml), and papaverine (1 microM) or by a tenfold higher concentration of dibutyryl cyclic AMP (1 mM) alone for 9 days. The retinoid 2-retinylidene-5,5-dimethyl-1,3-cyclohexanedione at 1 microM and the phorbol ester phorbol 12,13-didecanoate at 10 microM each blocked the induction process. The parameters of the induction and its prevention were analogous in many ways to those previously found with cultures of normal mammary glands of mice and humans, as well as of mouse prostate glands and chick embryo skin. The metaplastic squamous cells that developed in the cultured mammary outgrowths did not proliferate in gland-free mammary fat pads, possibly because the cells were terminally committed or because of insufficient inducers. In contrast, the alveolar and ductular epithelia in the same outgrowths have a transplantable pool of generative cells with the ability to undergo continual proliferation and development. The finding of precursor cells with the potential for epidermoid development and differentiation in the preneoplastic alveolar and ductular outgrowths, despite their extensive serial transplantations, is supportive of the existence of a common or closely associated pool of cells with the ability to develop either into squamous or alveolar mammary epithelium.

Invasion and metastasis of a xenogeneic tumor in nude mice.

When aliquots of a malignant hamster tumor were transplanted to nude mice and to hamsters, the tumor showed 1) more rapid growth in the hamster, 2) local invasion and metastasis in both species, and 3) occasional spontaneous regression in the nude mouse.

Elevated expression and cell cycle deregulation of a mitosis-associated target polypeptide of a carcinogen in hyperplastic and malignant rat hepatocytes.

A cytoplasmic polypeptide with a molecular weight of 14,000 (p14) was previously found to be the principal covalent target protein of the carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene), early during carcinogenesis in rat liver. The level of immunodetected p14 was markedly increased specifically during all stages of mitosis of hepatocytes in normal and regenerating partially hepatectomized livers. In addition, the polypeptide appeared to be immunologically and behaviorally related to a polypeptide with a molecular weight of 17,500 that is tightly bound to nucleosomes of chromatin in hepatocytes. This report describes the actions of the two polypeptides during hepatocarcinogenesis induced by ingestion of 3'-methyl-4-dimethylaminoazobenzene or N-2-fluorenylacetamide. Both carcinogens acted similarly in bringing about characteristic responses of the two polypeptides, detected immunohistochemically with specific rabbit antiserum and peroxidase-antiperoxidase complex. Four types of discrete hepatocytic lesions were observed. The earliest and least aberrant were hyperplastic foci of proliferating hepatocytes, which generally displayed markedly higher levels of immunostained p14 in cytoplasm, compared to levels in normal diploid hepatocytes. Furthermore, the very high concentrations of p14 were continuously present during cell interphase, in contrast to those in normal and regenerating hepatocytes, in which the elevation is restricted to the period of mitosis. Later-arising lesions were acidophilic adenomas of hepatocytes, which were characterized by quiescent morphology, fairly uniform and bulky eosinophilic cytoplasm, high levels of glycogen, and small delicate nuclei. These cells usually displayed little cytoplasmic p14. Coexistent hepatocytic lesions, i.e., mixed basophilic adenomas, exhibited considerable morphological heterogeneity, often slightly basophilic cytoplasm, and variable immunostain of cytoplasmic p14 during interphase. The fourth lesions were hepatocellular carcinomas, which continuously demonstrated much higher than normal levels of cytoplasmic p14 during cell interphase. During mitosis in the four types of hepatocytic lesions, the levels of immunostained p14 were usually further elevated above those in interphase, regardless of whether they were already very high during interphase in hyperplasia and malignancy, or low in acidophilic adenomas. All four kinds of carcinogen-altered lesions usually displayed little of the detectable Mr 17,500 polypeptide in nuclei.(ABSTRACT TRUNCATED AT 400 WORDS)

Induction of epidermoid differentiation by cyclic adenine nucleotide in cultured mammary tumors of mice.

In search of the degree of responsiveness of mammary adenocarcinomas to signals of differentiation, mouse mammary tumors were induced to undergo a course of development leading to multiple foci of squamous metaplasia, and subsequently a differentiation manifested by marked keratinization. The mammary tumors had spontaneously arisen in the preneoplastic mammary outgrowths of the transplantable lines, D1, MH5, and MH9, after their long-term implantation in gland-free mammary fat pads of virgin BALB/c mice. The inductions were produced in cultured fragments of mammary tumors by incubation for 9 days in the cyclic adenine nucleotide, N6-O2'-dibutyryl cyclic AMP, at 0.1 mM, without or with prostaglandins E1, E2, and B1, each at 5 micrograms/ml, and 1 microM papaverine. The N6-O2'-dibutyryl cyclic AMP alone was as active in the mammary tumors derived from the D1 and MH9 preneoplastic outgrowths as was the entire mixture of inducers. Intracellular cyclic adenine nucleotide may presumably be the specific mediator of the inductive process, presumably being elevated synergistically by entry of the N6-O2'-dibutyryl cyclic AMP, by induction of adenyl cyclase by prostaglandin E1 and E2, and through inhibition of phosphodiesterases by papaverine. Epidermidalization occurred to equal extent in well-differentiated and anaplastic mammary adenocarcinomas, indicative that mammary tumor progression did not affect the susceptibility to this course of development and differentiation. Mammary gland epithelium retains its susceptibility to multifocal epidermidalization in organ culture throughout the gradient of neoplastic transformation and progression toward decreasing growth regulation, starting from normal mammary gland, next preneoplasia (both reported previously), then well-differentiated neoplasia, and lastly anaplastic cancer. The findings support the existence of a common or closely associated pool of progenitor cells for the alveolar and epidermoid courses of development and differentiation in mammary gland. Induction of squamous metaplasia and abundant keratinization in both the well-differentiated and anaplastic mammary adenocarcinomas caused some of the cells to differentiate terminally and to die.

Normal hepatocytes exhibiting histone H3 with antibody accessible sites that are cryptic in carcinogen-altered hepatocytes.

A Mr 14,000 polypeptide (p14), identified as liver fatty acid binding protein, in normal liver cytosol was shown previously to be the principal target of the carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene), early during hepatic carcinogenesis in rats. Immunohistochemical analyses using rabbit antiserum against pure p14/liver fatty acid binding protein revealed marked increases in the levels of the protein in cytoplasm specifically during mitosis in normal and regenerating hepatocytes, and throughout the cell cycle in hyperplastic and malignant hepatocytes brought about by carcinogen, N-2-fluorenylacetamide (2-acetylaminofluorene) or 3'-methyl-4-dimethylaminoazobenzene. Present also in normal hepatocytes was a nuclear antigen that was not detected in the hyperplastic hepatocytes, benign hepatocytic adenomas, and hepatocellular carcinomas produced by these carcinogens. The nuclear antigen was discerned to be a Mr 17,000 polypeptide (p17) in extracts of normal liver nuclei and nucleosomes. In the present study, the p17 was purified by high-performance liquid chromatography and identified as being the three variants of histone H3, based on common molecular size, amino acid composition, electrophoretic migration in Triton-acetic acid-urea gels, and Western blot and histochemical reactions using affinity-purified antibodies. The histone H3 of all tested organs reacted specifically with the antiserum in Western blots following sodium dodecyl sulfate gel electrophoresis. In contrast, in a survey of 23 normal rat organs, nuclei of virtually only hepatocytes were reactive immunohistochemically. In view of the exceptional immunohistochemical reactivity of nuclei of normal hepatocytes, attributable to accessible histone H3, and the lack of such reaction in carcinogen-altered hepatocytes, the collected evidence indicates that normal hepatocytes contain uniquely available histone H3 sites that become cryptic during the chemical carcinogenesis.

Nononcogenic hormone-independent alveoli produced by carcinogens in cultured mouse mammary glands.

Treatment of mouse mammary glands with a high concentration of 7,12-dimethylbenzo(a)anthracene in whole organ culture was reported by Banerjee et al. to transform foci of lobuloalveoli to a hormone-independent state, and to give rise to mammary hyperplastic outgrowths and adenocarcinomas in vivo. In the present study using the identical system, mammary glands of BALB/c mice were exposed to 7,12-dimethylbenzo(a)anthracene or N-2-fluorenylacetamide at low concentrations that bring about maximal incidences of the hormone-independent hyperplastic lobuloalveolar lesions with minimal cytotoxicity. After morphological development of the lobuloalveoli in culture, the glands were enzymatically dissociated into cells and inoculated into gland-free inguinal mammary fat pads of syngeneic mice bearing pituitary gland implants during the initial 8 weeks. After 11 months, fragments of the resultant mammary outgrowths from each mouse were implanted into the gland-free inguinal mammary fat pads of 3 syngeneic mice (not bearing pituitary gland supplements) and were permitted to grow for another 11 months. Mammary outgrowths from the primary and secondary implants were neither neoplastic, anaplastic, nor dysplastic. Also, no hyperplasia in any mammary outgrowth could be attributed to the action of either carcinogen, especially when outgrowths were compared with contralateral outgrowths that arose from the control glands exposed to dimethyl sulfoxide (solvent of the carcinogens) in culture and/or with untreated thoracic mammary glands of the same hosts. One interpretation of these findings is that the hormone-independent, hyperplastic alveolar lesions may not be an appropriate in vitro marker of oncogenic transformation by chemical carcinogens in culture. The great variety of procarcinogens and activated carcinogens that bring about this lesion in vitro and its morphological similarity to presumptive mammary preneoplastic lesions in vivo weigh against this interpretation. A second hypothesis is that high concentrations of procarcinogens, despite their considerable cytotoxicity, complete a multistep process of oncogenic transformation in surviving mammary epithelium, whereas low concentrations optimized to produce the lesions in maximal number do not.

Pathological gambling. A psychobiological study.

We investigated psychobiological substrates of pathological gambling by measuring levels of norepinephrine, monoamine metabolites, and peptides in cerebrospinal fluid, plasma, and urine. Pathological gamblers had a significantly higher centrally produced fraction of cerebrospinal fluid levels of 3-methoxy-4-hydroxyphenylglycol as well as significantly greater urinary outputs of norepinephrine than controls. These results suggest that pathological gamblers may have a functional disturbance of the noradrenergic system. This system has been postulated to underlie sensation-seeking behaviors, aspects of which are thought to be abnormal among pathological gamblers.

Profile of the pathological gambler.

Pathological (compulsive) gambling is a serious emotional and social problem that has existed for centuries but has only recently been recognized as a distinct diagnostic entity that can be effectively treated. The development and progression of pathological gambling are outlined. The progression of the disorder through three identifiable phases leads to predictable complications. The treatment of the gambler within the framework of Gamblers Anonymous and/or by mental health professionals is described.

Pharmacokinetics of gentamicin in blood plasma of quail, pheasants, and cranes.

Rate of appearance, peak concentration, and the biological half-life of gentamicin in the plasma of quail (Coturnix coturnix), pheasants (Phasianus colchicus), and cranes (Grus canadensis tabida) were studied. Gentamicin was given IM in doses of 5, 10, and 20 mg/kg of body weight. Peak plasma concentrations occurred earliest in the quail, latest in the cranes. The peak concentrations varied directly with the administered doses in all species. The biological half-life of gentamicin was 42 +/- 12 minutes in the quail, 75 +/- 15 minutes in the pheasants, and 165 +/- 37 minutes in the cranes. On the basis of the present data, dosage regimens for gentaminic of 5 mg/kg every 8 hours in pheasants and cranes, and 10 mg/kg every 6 hours in quail, would be expected to give constant plasma concentrations greater than 4.0 micrograms/ml.

The Icr:Ha(ICR) mouse: a current account of breeding, mutations, diseases and mortality.

This stock of albino mice is minimally inbred (0.5% per generation), and has been rigidly selected for fecundity. It is widely employed in oncological and pharmaceutical research. Spontaneous tumours arose in 55% of animals, multiple in 28%, averaging 1.66 per mouse. Females developed tumours at an earlier age than males. Predominant tumour types were pulmonary (23.1%), lymphoreticular (20%), and mammary (14%--23% of females). Miscellaneous tumour types (42.9%) ranged in frequency from 0.2 to 2.0%, the latter being hepatomas. Distribution of mammary tumours indicated that milk-borne mammary tumour virus was absent. Non-neoplastic disease was present in 58.6%, 24.1% being pulmonary and predominant in the young, while renal (31.2%) and cardiovascular (10.2%) disease was common in the elderly. Males outlived females.

Use of dissociative anesthetics for the immobilization of captive bears: blood gas, hematology and biochemistry values.

Nineteen bears, representing five species (Helarctos malayanus, Ursus americanus, Ursus arctos, Tremarctos ornatus, Melursus ursinus) were immobilized a total of 52 times using either phencyclidine-promazine or tiletamine-zolazepam. Blood gas, hematology, and serum biochemistry values were determined during the immobilizations. Immobilizations conducted with tiletamine-zolazepam were characterized by rapid induction and recovery times, good muscle relaxation, and relative freedom from convulsions. Bears immobilized with phencyclidine-promazine had longer induction and recovery times and showed convulsive activity in 29% of the trials with that combination.

The acid-base status of lions, Panthera leo, immobilized with four drug combinations.

Fifty-eight immobilizations were conducted using 21 lions (Panthera leo) and 4 drug combinations. The combinations used were ketamine-phencyclidine-promazine, xylazine-phencyclidine-promazine, xylazine-ketamine-phencyclidine-promazine, and tiletamine-zolazepam.

Physiologic and acid-base measures of gopher snakes during ketamine or halothane-nitrous oxide anesthesia.

Arterial acid-base and selected physiologic measures of gopher snakes (Pituophis melanoleucus catenifer) during ketamine or halothane-nitrous oxide anesthesia were compared with base-line values. During ketamine anesthesia, significant decreases in pH and HCO-3 concentrations indicated acid-base states of uncompensated metabolic acidosis. In contrast, halothane-nitrous oxide anesthesia induced acidosis of respiratory origin, through a significant depression in respiratory rate. In addition to the conventional measures, the OH-/H+ ratios and the alpha-imidazole (alpha IM) values were calculated to assess acid-base status during anesthesia. Values for both factors decreased significantly during both ketamine and halothane-nitrous oxide anesthesia. Where H+ concentrations nearly doubled, the decline in the OH-/H+ ratio exceeded 70% and the alpha IM decreased less than 20%. It was concluded that these 2 factors may be helpful in evaluation of the acid-base status of ectothermic animals when normal values for the conventional measures of pH and pCO2 are not available for comparison.

Hematologic effects of xylazine when used for restraint of Bactrian camels.

Xylazine was found to be a safe and reliable drug for chemical restraint of Bactrian camels (Camelus bactrianus). Dosages of 0.27 to 0.51 mg/kg of body weight provided adequate sedation for the performance of various procedures (e.g., tuberculin testing, lymph node biopsy, and electroejaculation). Hematologic and serum biochemical values for camels restrained manually were compared with those for camels restrained with xylazine. Xylazine-treated camels had significantly lower values for RBC, hemoglobin, and packed cell volume, and significantly higher blood glucose concentrations. Venous blood gas analyses did not reveal any major acid-base disturbances resulting from the use of xylazine. Rapid arousal from the sedative effects of xylazine occurred after the intravenous administration of doxapram hydrochloride in dosages of 0.05 to 0.13 mg/kg of body weight.

Physiologic measures of nonhuman primates during physical restraint and chemical immobilization.

The arterial acid-base balance and other selected physiologic measures of physically restrained and chemically immobilized nonhuman primates from the families Callithricidae, Cebidae, Cercopithecidae, and Pongidae were compared. The physically restrained primates had significantly lower pH, pCO2, and base excess values, but they had significantly higher pO2 values, rectal temperatures, and pulse and respiration rates. Of 56 physically restrained primates, 30 (54%) experienced severe metabolic acidosis, with pH values less than 7.2; 15 (27% of total) had pH values less than 7.1. Two types of behavior were observed during the physical restraint of golden marmosets. Some of the marmosets were excited during restraint, with a great deal of struggling and vocalizing. The other marmosets were quiet and calm, with minimal struggling. The excited group had significantly lower pH, pCO2, and base excess values, but significantly higher pO2 values, rectal temperatures, and pulse and respiration rates. Primates immobilized with ketamine or tiletaminezolazepam had a near normal acid-base balance and were handled more easily than the physically restrained animals.