Limited overlapping roles of P15(INK4b) and P18(INK4c) cell cycle inhibitors in proliferation and tumorigenesis

Entry of quiescent cells into the cell cycle is driven by the cyclin D-dependent kinases Cdk4 and Cdk6. These kinases are negatively regulated by the INK4 cell cycle inhibitors. We report the generation of mice defective in P15(INK4b) and P18(INK4c). Ablation of these genes, either alone or in combination, does not abrogate cell contact inhibition or senescence of mouse embryo fibroblasts in culture. However, loss of P15(INK4b), but not of P18(INK4c), confers proliferative advantage to these cells and makes them more sensitive to transformation by H-ras oncogenes. In vivo, ablation of P15(INK4b) and P18(INK4c) genes results in lymphoproliferative disorders and tumor formation. Mice lacking P18(INK4c) have deregulated epithelial cell growth leading to the formation of cysts, mostly in the cortical region of the kidneys and the mammary epithelium. Loss of both P15(INK4b) and P18(INK4c) does not result in significantly distinct phenotypic manifestations except for the appearance of cysts in additional tissues. These results indicate that P15(INK4b) and P18(IKN4c) are tumor suppressor proteins that act in different cellular lineages and/or pathways with limited compensatory roles.

Immunohistologic detection of estrogen receptor alpha in canine mammary tumors: clinical and pathologic associations and prognostic significance

Eighty-nine canine mammary tumors and dysplasias of 66 bitches were investigated to determine the immunohistochemical expression of classical estrogen receptor (ER-alpha) and its clinical and pathologic associations and prognostic value. A complete clinical examination was performed and reproductive history was evaluated. After surgery, all animals were followed-up for 18 months, with clinical examinations every 3-4 months. ER-alpha expression was higher in tumors of genitally intact and young bitches (P < 0.01, P < 0.01) and in animals with regular estrous periods (P = 0.03). Malignant tumors of the bitches with a previous clinical history of pseudopregnancy expressed significantly more ER-alpha (P = 0.04). Immunoexpression of ER-alpha decreased significantly with tumor size (P = 0.05) and skin ulceration (P = 0.01). Low levels of ER-alpha were significantly associated with lymph node involvement (P < 0.01). Malignant tumors had lower ER-alpha expression than did benign tumors (P < 0.01). Proliferation index measured by proliferating cell nuclear antigen immunostaining was inversely correlated with ER-alpha scores (P = 0.05) in all tumors. Low ER-alpha levels in primary malignant tumors were significantly associated with the occurrence of metastases in the follow-up (P = 0.03). Multivariate analyses were performed to determine the prognostic significance of some follow-up variables. ER-alpha value, Ki-67 index, and age were independent factors that could predict disease-free survival. Lymph node status, age, and ER-alpha index were independent prognostic factors for the overall survival. The immunohistochemical detection of ER-alpha in canine mammary tumors is a simple technique with prognostic value that could be useful in selecting appropriate hormonal therapy.

The cell cycle inhibitor p21 controls T-cell proliferation and sex-linked lupus development

Here we show that the cell-cycle regulator p21 is involved in immune system function. T lymphocytes from p21-/- mice exhibit significant proliferative advantage over wild-type cells following prolonged stimulation, but not after primary activation. Consistent with this, p21-deficient mice accumulate abnormal amounts of CD4+ memory cells, and develop loss of tolerance towards nuclear antigens. Similar to human lupus, female p21-deficient mice develop antibodies against dsDNA, lymphadenopathy, and glomerulonephritis, leading to decreased viability. These data demonstrate a specialized role for p21 in the control of T-cell proliferation, tolerance to nuclear antigens, and female-prone lupus. These findings could be the basis for new therapeutic approaches to lupus.

Canine gonadal dysgenesis syndrome: a case of mosaicism (77,XO-78,XX)

A toy poodle bitch had an abnormal oestrus cycle and apparently persistent follicles. Hormonal therapy was unsuccessful. The bitch was ovariohysterectomised and gross and histological evaluation of the ovaries and uterus, together with karyotyping, led to a diagnosis of 77,XO-78,XX mosaicism.

Disease states associated with telomerase deficiency appear earlier in mice with short telomeres

Mice deficient for the mouse telomerase RNA (mTR-/-) and lacking telomerase activity can only be bred for approximately six generations due to decreased male and female fertility and to an increased embryonic lethality associated with a neural tube closure defect. Although late generation mTR-/- mice show defects in the hematopoietic system, they are viable to adulthood, only showing a decrease in viability in old age. To assess the contribution of genetic background to the effect of telomerase deficiency on viability, we generated mTR-/- mutants on a C57BL6 background, which showed shorter telomeres than the original mixed genetic background C57BL6/129Sv. Interestingly, these mice could be bred for only four generations and the survival of late generation mTR-/- mice decreased dramatically with age as compared with their wild-type counterparts. Fifty percent of the generation 4 mice die at only 5 months of age. This decreased viability with age in the late generation mice is coincident with telomere shortening, sterility, splenic atrophy, reduced proliferative capacity of B and T cells, abnormal hematology and atrophy of the small intestine. These results indicate that telomere shortening in mTR-/- mice leads to progressive loss of organismal viability.

Immunohistochemical localization of epidermal growth factor, transforming growth factor-alpha and growth factor-beta s in the caprine peri-implantation period

Control over the action of steroid hormones in the uterus and conceptus during the initial period of gestation appears to be regulated locally by growth factors. This study involved immunohistochemical detection of epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha) and transforming growth factor-beta s (TGF-beta s), to determine their role in the caprine peri-implantation period. Epidermal growth factor was expressed in the luminal and glandular endometrial epithelium of goats on all days studied (Days 22 to 30 post coitum), but it was not detected in trophoblastic cells or in other embryonic structures. Between Days 22 and 30 post coitum, TGF-alpha was detected in the epithelial cells and superficial stroma of the uterus and in the trophoendodermic cells of the embryo. Transforming growth factor-beta s expression, observed in the endometrium, embryo and extraembryonic membranes on Day 22 post coitum, decreased by Day 24 post coitum and disappeared in the embryo by Day 30 post coitum, while remaining in the other structures. The presence of these growth factors during the peri-implantation period in the goat suggests their participation in proliferation and differentiation phenomena which occur during implantation and embryonic development.

Caprine testicular hypoplasia associated with sexual reversion decreases the expression of insulin-like growth factor II (IGF-II) mRNA in testes

The genetic expression of insulin-like growth factor II (IGF-II) mRNA was studied in healthy adult testes and in hypoplastic testes of polled Murciano-Granadina goats by means of in situ hybridization. A positive reaction in spermatogonia, pachytene spermatocytes and a few peritubular myoid cells was observed using the ovine antisense oligonucleotide in healthy testes. The hypoplastic testes displayed a loss of germinal epithelium and a slight thickening of the basement membranes. A limited number of immature germinal cells displayed a lesser hybridization reaction, while the expression of IGF-II mRNA observed in the peritubular myoid cells was similar to that seen in healthy testes. In hypoplastic testes, IGF-II mRNA expression within germinal cells decreased with increasing hypoplasia within the seminiferous epithelium and there was no hybridization within the tubules in cases of severely disrupted spermatogenesis. These results suggest that testicular hypoplasia is associated with changes in the expression of IGF-II mRNA.

Histological and immunohistochemical study of the cat epididymis

A histological and immunohistochemical study of the epididymis of 21 cats which ranged from 7 to 8 months to 2 years of age was made. Five different cell types were observed in the feline epididymis: principal and basal cells, which were the most numerous, apical and narrow, PAS positive cells, which were scarce, and migratory cells, consisting of lymphocytes and macrophages. Four morphologically distinct areas of the cat epididymis were identified. Region I displayed a stellate lumen and the principal cells were tall and presented long and irregular stereocilia. In region II, the lumen was oval and the principal cells were shorter than in the initial area. Region III displayed characteristics similar to those of region I; the principal difference was the presence of short and regular stereocilia on the surface of the principal cells. In region IV the lumen was very spacious and the epithelium shorter than in the other regions. In regions I, II, and III intraepithelial cavities were observed. With regard to the immunohistochemical results, the basal cells displayed medium immunoreactivity with vimentin. Due to its anti-desmin reactivity, the muscle wall which surrounds the epididymis was seen to become progressively thicker as it nears the tail. Broad-spectrum anti-cytokeratin serum produced intense immunostaining in the basal, apical and narrow, PAS positive cells; the principal cells of region IV also displayed a strong immunoreactivity.

Histopathological changes in the reproductive organs of Manchego ewes grazing on lucerne

The effects of prolonged exposure to phyto-oestrogens (coumestrol) on the morphology of the reproductive organs of ewes were studied in 28 lucerne-grazing animals, and compared with 28 control ewes given a standard coumestrol-free diet. The anatomical studies showed that 43% of the ewes fed lucerne displayed macroscopic changes within the genital tract, of which the uterine alterations were especially prominent. The microscopic examination of the test group ewes identified specific histopathological features of the uterus and cervix. A greater than normal development of the cervical folds was observed, as well as cystic formations of different sizes whose content was eosinophilic. In the rest of the uterus, more glandular activity was detected in the lucerne-grazing group than in the control ewes, although cystic formations were not seen.

[Supply of blood to heart surgery patients. Can transfusion habits be changed?]

OBJECTIVE

In cardiac surgery, patients might receive unnecessary blood transfusions, due to the lack of a uniform criteria for blood replacement. We set out to evaluate the effect of a transfusion education program on the homologous blood requirements of subjects undergoing cardiac surgery.

METHODS

In June of 1993 a transfusion education program based on international criteria was designed and put into effect in the intensive care unit. Since that date, 133 patients (group 1), on whom we attempted to evaluate the effects of the program, were included, comparing them with 150 control patients (group 2) from the previous year. Multiple variables were analyzed, in order to confirm that the factors that could affect the use of blood did not differ between the two groups. The impact of these variables and the program on the homologous blood expenditures was measured with uni and multivariant analyses.

RESULTS

Blood requirements of the patients during the first day of the postoperative period were 0.9 +/- 0.1 U in group 1 versus 1.8 +/- 0.1 U in group 2 (p < 0.001) and the requirements during their entire stay in ICU were 1.8 +/- 0.1 versus 2.6 +/- 0.1 (p < 0.005). There were significant differences between both groups: Hemoglobin level at the admission in ICU, anoxia time, extracorporal circulation time, and blood losses in the first 24 hours of their stay in ICU. However, the analysis of covariance showed that the transfusion program exerted an independent influence, apart from other variables, over the decrease of blood transfusions. Morbidity and mortality were similar in both groups.

CONCLUSIONS

Transfusion habits can be modified, permitting a lesser consumption of homologous blood through the adoption of education programs adapted to the diseases in which they will be applied.

[The prognostic value and evolution of blood pressure during an acute phase of stroke]

We studied the prognostic influence and evolution of blood pressure during the acute phase of stroke in 89 patients (50 men and 39 women) with an average age of 69.4 +/- 10.8 years. Seventy-two were diagnosed as having ischaemic infarct and 17 as having spontaneous intracerebral haemorrhage. Blood pressure was taken every four hours for twelve days. Clinical situation was evaluated using the Rankin scale. Systolic and diastolic blood pressure progressively decreased without needing any medication in the first two weeks of evolution. The decrease was greatest in hypertense patients and in those with left ventricle hypertrophy. We found the initial figures for systolic and diastolic blood pressure significantly higher in those patients with brain infarct who had not died and in those in a better functional position the second week of evolution. Blood pressure did not influence the prognosis of intracerebral haemorrhage patients.

Immunocytochemical study of type IV collagen and laminin in canine mammary tumours

We performed an immunohistochemical study of the basement membrane (BM) proteins laminin and type IV collagen in 35 canine mammary tumours, histologically classified according to the World Health Organization's suggested classification. Laminin and type IV collagen were seen in extracellular locations but only laminin was present in epithelial and myoepithelial cells and chondrocytes. The BM was always continuous in adenomas and fibroadenomas. In the 20 malignant tumours studied, the basement membrane was continuous in one, discontinuous in five, and virtually absent in 14. When present, the BM of malignant tumours varied in width and distribution in the same area. The benign and malignant mixed tumours did not have BM separating epithelial and newly-formed mesenchymal structures. In areas of abundant myoepithelial cells in complex and mixed tumours, both benign and malignant, there were groups of BM fragments which differed in length and thickness and occasionally formed tangles. We have called these 'membranous thickets'. Our results indicate that myoepithelial cells are the main source of the BM proteins laminin and type IV collagen in canine mammary tumours.

Eosinophilic gastroenteritis syndrome in a dog

We performed a clinical and pathological study of a 5 year old female mongrel dog (Drahthaar) with eosinophilic gastroenteritis. The animal was presented with vomiting and was reported to have had bloody diarrhoea for 4 months. The lesions were in atypical locations: in the fundus of the stomach, the ileocaecal valve and the rectum, near the anal sphincter. The lesions in the stomach wall were particularly severe and included severe fibroplasia, especially in the muscle layer and submucosa. Fibroplasia was less visible in the other locations. The presence of eosinophilic granulomatous masses led us to suspect a possible parasitic infection, although some authors note that this pathological condition may have an allergic aetiology.

Histological changes in the uterus during postpartum in the mare

An histological study of the postpartum period in 29 mares was carried out. Uterine biopsies were taken daily during the first 10 days postpartum in a total of 87 samples. At day 0, equine endometrium was characterized in the surface by the presence of regularly ordered microcaruncles; the stratum spongiosum was oedematous and contained distended and scarce glands. Degenerative changes in microcaruncles and endometrial glands were present on day 1 postpartum. The epithelium of the microcaruncles from 2 to 5 days postpartum showed cytoplasmic vacuolization, karyorrhexis and an inflammatory reaction with neutrophils and phagocitic cells. On day 7 postpartum, the histology of the endometrium was similar to the normal proestrus with cuboidal luminal epithelium and an oedematous stromal tissue. The changes are usually completed within days 9 and 10 postpartum with the histologically typical appearance of estrus in mares.

Histological study of Leydig cells in the cat from birth to sexual maturity

Testes of 20 cats with an age ranging from 1 day to 1 year were obtained. Histological study revealed three different populations of Leydig cells. In the early postnatal period (from birth to 1 month) they were round or polyhedral with an ovoid and eccentric nucleus. From 2 to 4-5 months Leydig cells were similar to those seen in the early postnatal period, showing shrunken nuclei with condensed chromatin masses and accumulation of lipid droplets in the cytoplasm. The peritubular Leydig cells mostly contained elongated nuclei. From 5 to 6 months of age adult Leydig cells were encountered, generally polygonal in outline with large nuclei that were usually round to ovoid and displaced to one side of the cell. The cytoplasm contained lipid droplets and lipofuscin granules. The number of testosterone-containing cells decreased progressively from 1 to 4 months; from 3 to 4 months only a small number of testosterone-containing cells were present.

Immunocytochemical identification of a bovine peritoneal mesothelioma

Peritoneal mesotheliomas are uncommon among cows although there has been an increase in the frequency of diagnosis of this neoplasia in the past few years. The case of a 2 year old cow is described. On post-mortem examination, several nodules of variable size were found in the peritoneal cavity. These nodules fused together, but they did not go deep into the organs. Histologically, such nodules were formed by a population of fusiform cells of malignant morphological character and sarcomatous appearance. Immunocytochemical study, using P.A.P. techniques, showed a highly positive reaction towards vimentin and a negative reaction towards wide-spectrum cytokeratins, hence suggesting a mesenchymal origin of the neoplasia. According to the histopathological study, a multifocal peritoneal mesothelioma of sarcomatous appearance was identified.

Immunocytochemical study of the diffuse neuroendocrine system cells in equine lungs

This study was undertaken to investigate the presence of neuroendocrine cells (N.E.C.) by immunocytochemical means in equine lungs during three distinct evolutionary periods: fetal, neonatal and adult. The authors identified bombesin, somatostatin and calcitonin secretory cells. In the fetal lungs the N.E.C. were located in the interstitial tissue and exhibited greater immunoreactivity to bombesin than to the other two neuropeptides studied. A large number of calcitonin-producing cells and a smaller number of bombesin-positive cells were seen in the bronchial and bronchiolar epithelium of newborn Equidae. In the adult equine lungs far fewer N.E.C. were observed than in the earlier stages. Somatostatin-producing cells were not seen in neonatal or adult lung tissue.

Glomerular lesions in Aleutian disease of mink (Mustela vison): a morphological and differential morphometrical study

A morphological and morphometrical study has been carried out on glomerular lesions in mink with spontaneous Aleutian disease, using the WHO classification for Systemic Lupus Erytematous Nefritis. 154 renal samples from sick animals and 10 samples from uninfected mink were processed by routine histopathological techniques and metacrylate inclusions. The samples were studied quantitatively with an automatic image analyzer. 5 forms of glomerulonephritis (GN) were identified: mesangial glomerulonephritis (n = 13), focal and segmental GN (n = 10), diffuse GN (n = 99), membranous GN (n = 12) and advanced sclerosing GN (n = 10) and were associated with the degree of interstitial plasmocytosis. Glomerule morphometry was shown to be an excellent method for identifying the type of lesion, while it quantified the participation of various glomerular elements in the lesion.

Flow cytometric analysis of oestrogen receptors in relation to histopathologic characteristics of DMBA-induced mammary tumours in rats

Experimental DMBA (7,12-dimethylbenzanthracene)-induced mammary tumours in Sprague-Dawley rats are studied. Percentages of the distinct types of adenocarcinomas (Stevens et al. 1965) were as follows: type A (poorly-differentiated), 8.8%; type B (well-differentiated), 65.5%; type C (atrophic), 15.5% and type D (secretory), 5.4%. 51% of the mammary adenocarcinomas were seen to be positive to oestradiol receptors by means of flow cytometry; type A adenocarcinomas were found to be the most frequent positive tumours (88.9% positive cases) whereas the last adenocarcinomas to appear (type D) were negative. These results suggest that the oestradiol-sensitivity of DMBA-induced mammary adenocarcinomas decreases as the post tumour-induction period lengthens.

Intermediate filaments in DMBA-induced mammary adenocarcinomas in rats

Experimental DMBA (7,12-dimethylbenzanthracene)-induced mammary tumours in rats were studied. Microscopic examination revealed a high rate of adenocarcinomas (95.3% in 148 mammary tumours studied). An immunohistochemical study of cytoskeleton intermediate filaments (I.F.) showed cytokeratins in neoplastic epithelial cells; myoepithelial cells expressed cytokeratins, vimentin and desmin. Finally we propose the immunocytochemical localization of desmin as a useful method to recognize myoepithelial proliferation areas in mammary tumours.

[Serum and immunological markers of progression to acquired immunodeficiency syndrome in hemophiliacs]

In a cohort of 30 randomly selected hemophiliacs who were prospectively controlled for four years the predictive value of AIDS development was evaluated for serum markers of HIV infection and for lymphocytic subpopulations in peripheral blood. The patients were evaluated with a mean of 15.79 +/- 5.74 months, and overall antibodies, specific antibodies (anti-ENV and anti-p24), HIV antigen (Ag HIV) and lymphocyte subpopulations were determined. 50% of the hemophiliacs with positive serum Ag HIV (2/4) developed AIDS during the study, whereas this progression was not recorded in any anti-HIV positive, nonantigenic patient. The presence of Ag-HIV was detected at least two years before the diagnosis in these patients, and it was associated with the absence of anti-p24 in one or more determinations. The immune regulation parameters were not significantly different, at the beginning of the study, in the hemophiliacs who developed AIDS and in those who did not. However, the progression to AIDS was associated with a significantly smaller T4/T8 ratio at least one year before the diagnosis. Our results show that the development of AIDS in hemophiliacs is associated both with the presence of Ag-HIV in the serum and a reduction in the T4/T8 ratio, although the detection of the former appears to be earlier than that of the latter in this risk group.

Visual pigments and retinoids in the Mongolian jird

The visual cells, visual pigments and major retinoids of the Mongolian jird (Meriones unguiculatus) were examined. Light and electron microscope analyses show that these jirds had mainly rod photoreceptors. Octylglucoside extracts prepared from their retinas contained only rhodopsin with a maximum absorption at 497 nm and a concentration of 0.51 nmol per retina. Employing a standard method of high performance liquid chromatography (HPLC), the pigment epithelium from each eye was found to possess 0.52 nmol of retinyl palmitate (the most abundant form of retinyl ester) along with a small amount of retinol (0.02 nmol). Most of the retinoids in the body of these animals are stored in the liver, in the form of retinyl palmitate (1228.80 nmol per gram liver). As the Mongolian jird is small, inexpensive and readily available, this animal is a mammalian species suitable for the research of the biochemistry of retinoids and vision.

Decreased hepatic retinyl palmitate hydrolase activity in protein-deficient rats

28-day-old weanling rats were fed a diet containing 3% casein as the only source of protein for eight weeks to induce protein deficiency. When compared to control animals (fed a diet containing 25% casein), these rats had significantly lowered body (5.2-fold reduction) and liver (2.5-fold reduction) weights. The circulatory level of retinol (nmol per ml plasma) as well as retinol (nmol per g tissue) in the liver of these protein-deficient animals were also reduced significantly, although their liver concentration of retinyl palmitate (nmol per g tissue) was comparable to that of the control group. Assay of liver tissue for retinyl palmitate hydrolase activity revealed a 4-fold reduction (compared to that of control animals) of specific enzyme activity (nmol retinol formed per g protein per h). These findings suggest that severe protein deficiency results in a decreased hydrolysis of retinyl esters in the liver, which may be in part responsible for the reduced level of metabolically 'active' retinoids available for normal physiological functions.

The in vivo regeneration of goldfish rhodopsin and porphyropsin

Goldfish with retinas rich in either rhodopsin or porphyropsin were illuminated with bright light and then placed in the dark room to allow visual pigment regeneration. The kinetics of this in vivo pigment regeneration were followed by sampling these animals at regular time intervals. The first-order kinetic rate constant for the initial period of porphyropsin regeneration at 20 degrees C was 8.3 X 10(−3) nmol kg-1 body weight min-1 and the half-life of this reaction was 83 min. At 30 degrees C, the rate constant was increased to 1.4 X 10(−2) nmol kg-1 body weight min-1, yielding a reduced half-life of 49 min. This suggests that the Q10 of porphyropsin regeneration is about 1.7. In goldfish retinas enriched with rhodopsin (62% rhodopsin and 38% porphyropsin), the initial phase of visual pigment regeneration (at 30 degrees C) proceeded at a slower rate (first-order rate constant: 6.5 X 10(−3) nmol kg-1 body weight min-1; half-life of reaction = 106 min) than the rate of porphyropsin regeneration. This suggests that the high proportion of rhodopsin in the retina of goldfish held at 30 degrees C is not a direct result of a faster rate of regeneration of rhodopsin than of porphyropsin.

[Type A adenocarcinoma grafted into C3H/he-M mice subjected to treatment with various antineoplastic agents. I. Biological study]

The biological modifications in C3H/he-M mice treated with vincristine, prospidium chloride and adriamycin are studied. A significative reduction of the tumor volume was observed with prospidium chloride and adriamycin treatment. The index of tumour growth inhibition (I0) is very high and corroborates the obtained results. The histopathological and ultrastructural studies will be published later.