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Biomedical subjects

G Reznik

Publications and source records attributed to G Reznik.

At least 37 records · Page 2Linked to original sources
PubMed1981

Urine cytology: early diagnosis of induced carcinoma of the rat urinary bladder.

Transitional cell carcinoma of the urinary bladder was induced in F344 rats by intragastric intubation of the animals with the known bladder carcinogen N-nitroso-N-methyl-N-dodecylamine (NMDA). Urinary cytology was used to follow the development of bladder lesions. As early as 8 weeks after the beginning of NMDA exposure, small, but distinct, differences could be detected between the morphology of exfoliated transitional cells found in the urine if animals treated with NMDA and those of control animals. Atypia was noted in the cells from some of the NMDA treated animals at about 20 weeks, and after 32 weeks definitely malignant transitional cells were identified in the urine of all NMDA treated animals. When the NMDA treated animals were killed, at 55-60 weeks after the beginning of NMDA treatment, transitional cell carcinoma of the urinary bladder was confirmed in all animals. No abnormal cells were noted in urine from any of the control animals. Urine cytology is an excellent technique for early detection of experimental urinary bladder cancer, and may be especially useful in screening industrial workers exposed to suspect bladder carcinogens.

Animals↗
PubMed1981

Morphology of nasal cavity neoplasms in F344 rats after chronic feeding of p-cresidine, and intermediate of dyes and pigments.

p-Cresidine was administered in the feed at either of two concentrations (0.5 and 1.0 percent) to groups of 50 male and 50 female F344 rats for 104 weeks. Fifty animals of each sex were placed on test as controls and fed only the basic laboratory diet. All animals were observed for up to 2 weeks after discontinuation of treatment. In treated rats of both sexes, statistically significant numbers of adenomas, adenocarcinomas and squamous cell carcinomas were diagnosed in the nasal cavity. Most of the neoplasms were seen in the high dose male and female rats. 22 male rats (49%) showed poorly differentiated adenocarcinomas infiltrating the skull and brain. Only two male rats (4%) had a squamous cell carcinoma, whereas 8 female rats (17%) had squamous cell carcinomas and 14 female rats (30%) were diagnosed as having adenocarcinomas of the nasal cavity. In the 4 neoplasms studied ultrastructurally, features characteristic of adenocarcinomas were identified. Cells were arranged around central lumina lined with microvilli. The luminal edges of cells were linked together by junctional complexes. Cytoplasmic differentiation was generally poor, with ribosomes and polyribosomes being the predominant organelles. Neurogenic features were rare and difficult to identify due to unsatisfactory fixation. In one of the tumors, areas of squamous differentiation were found. The cells constituting such areas contained prominent bundles of tonofilaments which are characteristic of early squamous metaplasia.

Aniline Compounds↗
PubMed1981

Pathogenesis of toxic and neoplastic renal lesions induced by the flame retardant tris (2,3-dibromopropyl)phosphate in F344 rats, and development of colonic adenomas after prolonged oral administration.

Male F344 rats, 4 weeks old, were given tris (2,3-dibromopropyl)phosphate (TBP) via stomach tube at a dosage level of 100 mg. per kg. of body weight per day. Treatment was given 5 days per week and continued for 4 or 52 weeks. Representative treated and control animals were killed at predetermined time intervals and the histomorphology and ultrastructure of the kidneys investigated. Twenty-four hours after the first TBP treatment, the epithelial cells at the corticomedullary junction developed increased nucleus to cytoplasm ratios, cytomegaly, and nuclear vacuolization and pleomorphism. These changes increased in severity to a toxic tubular nephrosis as treatment continued, and extended to the peripheral cortex by 52 weeks. Electron microscopy showed loss of microvilli and polarity in the epithelium of the proximal convoluted tubules. The development of adenocarcinomas from hyperplastic areas at these sites were studied. At the ultrastructural level, the cytoplasm of the neoplastic cells was poorly differentiated, and in many areas, the surfaces of the cells were covered by microvilli. In one group of rats, treatment was terminated after 4 weeks. In these animals, a gradual but incomplete restoration of the tubular epithelia to nearly normal morphology was observed. Nuclear changes persisted after cytoplasmic abnormalities had disappeared. At 52 weeks, three of five surviving rats given TBP throughout the experiment were found to have polypoid adenomas of the descending colon.

Adenoma↗
PubMed1980

Respiratory pathology in rats and mice after inhalation of 1,2-dibromo-3-chloropropane or 1,2 dibromoethane for 13 weeks.

Seventy F344 rats and 144 B6C3F1 mice were subdivided into seven groups. Three groups were each exposed via inhalation to 1, 5, or 25 ppm of 1,2-dibromo-3-chloropropane (DBCP) for 6 h per day, 5 days per week for 13 weeks. Three additional groups were each similarly exposed to 3, 15, or 75 ppm of 1,2-Dibromoethane (EDB). The remaining group was exposed to room air under the same conditions. At 13 weeks, rats and mice showed severe necrosis and atrophy of the olfactory epithelium in the nasal cavity after inhalation of 5 or 25 ppm DBCP and 75 ppm EDB. Lower concentrations induced squamous cell metaplasia, hyperplasia and cytomegaly of the epithelium of the respiratory nasal turbinals. Squamous metaplasia, hyperplasia and cytomegaly of the epithelium was also seen in larynx, trachea, bronchi and bronchioles. Other compound related toxic lesions in rats were seen in the liver, kidney and testes.

Animals↗
PubMed1980

Morphology and sex-dependent manifestation of nasal tumors in B6C3F1 mice after chronic inhalation of 1,2-dibromo-3-chloropropane.

Groups of 50 B6C3F1 mice of each sex were exposed to air containing of 1,2-dibromo-3-chloropropane at concentrations of 0.6 or 3.0 ppm for 6 hours per day, 5 days per week for 103 weeks. Untreated controls consisted of 50 mice of each sex. All surviving animals were killed at 104 weeks. Adenomas, squamous cell papillomas, adenocarcinomas, squamous cell carcinomas, carcinosarcomas, fibrosarcomas, and hemangiosarcomas of the nasal cavity occurred in male and female mice with dose related trends. Eighty-seven percent of the high dose female mice had nearly twice as many tumors as the high dose males (47%). Fourtynine percent of malignant neoplasms of the high dose female mice infiltrated the brain or metastasized to the lungs. Whereas two animals (4%) of the low dose female mice showed infiltrating carcinomas, no male mice exhibited this feature.

Animals↗
PubMed1980

Atrophy induced in the tubules of the testes of Syrian hamsters by two retinoids.

This paper describes toxic lesions induced in the hamster testes by 3 different retinoids. Groups of 13 Syrian Golden hamsters were fed diets containing 120 mg/kg 13-cis-retinoic acid (CRA), 327 mg/kg ethyl retinamide (ER), or 343 mg/kg 2-hydroxyethyl retinamide (HER) for 6 months. The germinal epithelium of the testicular tubules was completely atrophic in the groups fed ER and HER. Mean testicular weights were 0.8 g and 0.7 g respectively as compared to 3.3 g in the control group. No alterations in testicular weights or morphological characteristics, at the light microscopic level, were found in the group fed CRA. At the ultrastructural level, however, asymmetrical head caps and deformed acrosomes were observed in the spermatids.

Animals↗
PubMed1980

Lung tumors induced by chronic inhalation of 1,2-dibromo-3-chloropropane in B6C3F1 mice.

1,2-Dibromo-3-chloropropane (DBCP) was inhaled by B6C3F1 mice of each sex at concentrations of 0.6 or 3.0 ppm for 6 h/day, 5 days/week, for 103 weeks. Untreated controls consisted of 50 mice of each sex. All surviving animals were killed at 104 weeks. Survival in the high-dose groups of female mice was significantly shorter than that in the corresponding controls. Alveolar-bronchiolar adenomas or carcinomas occurred in both male and female mice with dose-related trends (P < 0.007) in males and (P < 0.002) in females. Papillary carcinomas in the lung occurred in low-dose female mice at an increased incidence compared with controls (P < 0.006). Many induced tumors were morphologically different than those in controls.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1980

Morphology of nasal-cavity tumours in rats after chronic inhalation of 1,2-dibromo-3-chloropropane.

Groups of 50 F344 rats of each sex sere exposed to 0.6 or 3.0 pts/10(6) of 1,2-dibromo-3-chloropropane (DBCP) by inhalation for 6 h/day, 5 days/week for 103 weeks. Fifty rats of each sex inhaling filtered air were used as unexposed controls. All survivors were killed at 104 weeks. Up to 93% of the male and female rats developed neoplasms of the nasal cavity. Most of the tumours were adenomas, squamous-cell papillomas, squamous-cell carcinomas, and adenocarcinomas. In the low-dose group 78% of the tumours in males and 66% in females were benign, whereas in the high-dose groups 89% in males and 76% in females were malignant. Invasion through the cribriform plate into the cerebrum or metastasis to the regional lymph nodes was found in 73% of the carcinomas in males and 51% in females. Electron-microscopic examination suggested that the basal cells of the olfactory epithelium were the site of origin of the poorly differentiated adenocarcinomas.

Adenocarcinoma↗
PubMed1980

Deposition and clearance of labeled cigarette smoke particles in rat respiratory and digestive tract.

In this investigation 160 8-wk-old Sprague-Dawley rats inhaled smoke from 14C-labeled cigarettes in a Hamburg II smoking machine. The research cigarettes were labeled with [16,17-14C]dotriacontane. Eighty of the rats were acclimatized to smoke from nonlabeled research cigarettes for 21 d before inhaling labeled cigarette smoke. The investigation was divided into four experiments. In experiment I all rats were killed immediately after exposure to the 14C-labeled smoke from 30 cigarettes (10 muCi per cigarette) and the organs of the respiratory and digestive tracts were measured for 14C activity. These animals showed high activity in the apex nasi, fundus nasi, and larynx. The highest activity was found in the lobus dexter caudalis and the lobus sinister of the lung. The lungs contained four-fifths of the condensate inhaled into the respiratory tract. In experiment II three animals were killed immediately after smoking, three after 6 h, and four after 24 h. No activity was found after 6 h in apex, fundus nasi, larynx, and trachea. The lungs showed no clearance at all. The activity in the digestive tract was highest in the stomach and the esophagus immediately after cessation of smoking. These values decreased rapidly after 6 h. In experiment III the animals were killed after 7, 21, and 42 d. Clearance from the upper respiratory tract was fast, whereas clearance from the lungs was slow. Clearance from all lung lobes was faster in the nonacclimatized animals. In experiment IV the rats inhaled the smoke from 14C-labeled cigarettes (2 muCi per cigarette) on 5 successive days. The animals were killed 7, 14, and 21 d after the last smoke inhalation. Clearance from the lungs was slower in acclimatized and non-acclimatized animals than in experiment III.

Animals↗
PubMed1980

Proliferative lesions of the spleen in male F344 rats fed diets containing P-chloroaniline.

Fifty male F344 rats were given diets containing 500 mg/kg P-chloroaniline. Controls received diets without the chemical. Eighteen of the dosed rats developed proliferative lesions of the spleen. Lesions included parenchymal fibrosis and fatty infiltration, well and poorly differentiated fibrosarcomas, osteosarcomas and hemangiosarcomas. All dosed rats had focal and diffuse fibrosis and papillary hyperplasia of the splenic capsule.

Aniline Compounds↗
PubMed1980

Ganglioneuromas in the adrenal medulla of F344 rats.

Of 60,048 aging F344 rats, 28 had ganglioneuromas of the adrenal gland. The rats were between 58 and 122 weeks old; 25 of them between 93 and 122 weeks when the tumors were found. The neoplasms were composed of large or small typical ganglion cells with a large pale nucleus and a prominent, often eccentric, nucleolus. The ganglion cells usually were distributed throughout the medullary tumor and surrounded by various numbers of supporting cells, including Schwann's cell types, and capsular or satellite cells. Often there was no clear-cut border between ganglion cells and neoplastic pheochromocytes. Electron microscopy of re-embedded tissues showed neurosecretory granules and cytoplasmic areas with an extensive rough endoplasmic reticulum (Nissl substance) in the ganglion cells and axons. The Schwann's cells were surrounded by a basement membrane and formed long cytoplasmic extensions around the axons. Almost all ganglioneuromas were associated with neoplastic pheochromocytes which usually were located at the edge of the tumors.

Adrenal Gland Neoplasms↗
PubMed1980

Effect of cigarette smoke inhalation during pregnancy in Sprague-Dawley rats.

Pregnant 9 weeks old Sprague-Dawley rats were exposed to the smoke of different research cigarettes (C1-C7). The cigarettes were different in smoke nicotine, condensate and carbon monoxide. The animals were divided in groups inhaling different smoke concentrations, numbers of inhalations per day and time periods per pregnancy. Carbon monoxide and dioxide content in the inhalation chamber increased dependent on time and concentration of smoke inhalation. Both parameters were highest after inhalation of smoke from cigarette C2. The weight of the pregnant rats was reduced after inhalation of high concentrations of smoke from cigarette C1 and c2. Weight and length of fetuses were reduced dependent on number and duration of smoke inhalation. High concentrations of cigarette smoke, twice daily for 21 days were more effective than smoke inhalation in the second part of the pregnancy. Inhalation of cigarette smoke during the second half of the pregnancy was more effective than smoke inhalation in the first ten days of pregnancy. cigarette C1 reduced the length and weight of fetuses more than cigarette C2 when concentration and number of inhalations per day were the same. The vapor phase in both cigarettes was not as effective as the total smoke. Resorptions and stillbirths were independent of treatment. Malformations were diagnosed only in one fetus.

Air↗
PubMed1980

Pathology of the clitoral and prepucial glands in aging F344 rats.

Clitoral and prepucial glands from 112-week-old untreated F344 male and female rats were studied histologically. Lesions included acinar cell atrophy, fibrosis, duct distension, inflammation, and neoplasms. Acinar cell atrophy and fibrosis were seen in 68% of the males and 58% of the females. More severe acinar cell atrophy, fibrosis, and inflammation were seen in the male rats. The neoplasms were small and circumscribed, cystic, or papillary cystic adenomas derived from acinar cells. One cystic adenocarcinoma was diagnosed.

Aging↗
PubMed1980

Deposition and clearance of 14C-labelled cigarette smoke particles in Syrian hamster respiratory and digestive tract.

Eight week old male and female Syrian golden hamsters inhaled smoke of Dotriacontane-16, 17- 14C-labelled research cigarettes. The investigation consisted of 4 experiments and each experiment involved 4 groups of 10 animals each. Eighty of the animals (40 males: 40 females) were killed immediately after exposure to the 14C-labelled smoke of 30 cigarettes (10 uCi/cigarette) and the organs of the respiratory and digestive tract were measured for their 14C-activity. Non-acclimatized Syrian golden hamsters inhaled quantitatively more condensate/g organ weight than acclimatized animals. There was no difference between males and females. Nearly 50% of the retained 14C-activity was found in the digestive tract, half of the amount was in the forestomach. The distribution in the respiratory tract showed no difference between acclimatized and nonacclimatized animals. More than 75% of the measured activity in the total respiratory tract was found in the lung. The highest concentration was measured in the lobus dexter caudalis and lobus sinister. The clearance of the lung was slower in acclimatized hamsters than in non-acclimatized animals. When animals inhaled the smoke of labelled cigarettes for five days the clearance of the lung was slower in acclimatized hamsters than in non-acclimatized animals.

Animals↗
PubMed1980

Histogenesis and morphology of naturally occurring prostatic carcinoma in the ACI/segHapBR rat.

The prostates of 201 male virgin or breeder ACI (ACI/segHapBR) rats, 24 to 40 months of age were reviewed histologically, and the genesis of prostatic carcinoma was studied. At 24 months of age, 35 to 45 per cent of the rats had the earliest lesions, intraalveolar atypical hyperplasias. These lesions progressed to intraalveolar cribriform carcinomas which spread along alveoli and ducts. As the tumors enlarged, they became nodular and invaded the capsule or adjacent tissues. By 33 months, 95 to 100 per cent of the rats had intraalveolar prostatic atypical hyperplasias, and 35 to 40 per cent had invasive carcinomas. There was no difference between the incidence of these tumors in virgin or breeder rats. The ACI rat is unique model for studying the etiology and pathogenesis of naturally occurring prostatic cancer.

Adenocarcinoma↗
PubMed1979

The influence of chemotherapy on the distribution of 57Co-bleomycin in chemically induced squamous cell carcinoma of mouse skin.

Organ distribution and tumor uptake of 57Co-bleomycin (BLM) were examined in NMRI mice without tumor and with chemically (DMBA-) induced squamous cell carcinoma. In these tumors high accumulation of 57Co-BLM was recorded shortly after injection of 57Co-BLM and low uptake 24--48 h after application. Two groups of tumor-bearing mice received unlabeled bleomycin as a cytostatic in two different doses. Uptake of 57Co-bleomycin was reduced. The study suggests that in patients currently or previously under chemotherapy, 57Co-bleomycin tumor scintigraphy may lead to false negative results.

Animals↗
PubMed1979

Renal carcinogenic and nephrotoxic effects of the flame retardant tris(2,3-dibromopropyl) phosphate in F344 rats and (C57BL/6N X C3H/HeN)F1 mice.

Tris(2,3-dibromopropyl) phosphate (TBP) was administered in the feed at one of two concentrations to groups of 55 male and 55 female inbred F344 rats and to 50 male and 50 female (C57BL/6N X C3H/HeN)F1 mice. The high and low dietary concentrations of TBP administered orally were 100 and 50 ppm for the rats, respectively, and 1,000 and 500 ppm for the mice, respectively. For each rodent type, 55 animals of each sex were used as contols. In both rodent types, renal epithelial tumors developed at incidences that were significant for male and female rats and mice that received the doses. These tumors included renal tubular cell adenomas and carcinomas that developed from the proximal convoluted tubular epithelium. Among female mice and rats, hyperplasia and/or dysplasia of the proximal convoluted tubular epithelium with or without cystic dilatation of the tubules and increase in the size of cell nuclei were dose dependent and recognized as preneoplastic and/or toxic lesions. The comparative histogenesis of renal tubular neoplasms was discussed.

Adenocarcinoma↗