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Biomedical subjects

A M Rossi

Publications and source records attributed to A M Rossi.

At least 37 records · Page 2Linked to original sources
PubMed1992

Enhanced hprt mutant frequency but no significant difference in mutation spectrum between a smoking and a non-smoking human population.

Recently, we have observed a small (36%), but significant, enhancement of the frequency of 6-thioguanine (6-TG)-resistant T-lymphocytes in blood from smokers. The molecular nature of 43 hypoxanthine-guanine phosphoribosyltransferase (hprt) mutant T-lymphocyte clones from nine smoking individuals was determined to investigate whether the increase in hprt mutant frequency would lead to a changed mutation spectrum. The types and distribution of hprt mutations in smokers was compared with those found in 55 6-TGr T-lymphocyte clones from 12 members of a control group of non-smokers. From this control group 25 hprt mutants were novel, whereas 31 have been described previously. Among smokers and non-smokers, a similar proportion of base substitutions (approximately 35%), mutations causing aberrant splicing (approximately 37%), frameshifts (approximately 16%) and deletions (approximately 9%) was found. In both groups, GC----AT base pair changes were found to be predominant among transitions. However, whereas all types of transversions were about equally represented in non-smokers, GC----TA transversions were not recovered among smokers. Investigation of the distribution of base substitutions over the hprt coding region showed no differences between the two groups. These data provide no clues on the nature of DNA adducts induced by smoking, which are thought to be responsible for the increased mutation frequency at the hprt locus in T-lymphocytes from smokers.

Adult↗
PubMed1991

Expression of growth-regulated genes in normal and SV40 transformed hamster fibroblasts.

Transformation by the oncogenic virus SV40 has been shown to alter the expression of cellular genes at the level of RNA abundance. Many of these genes have yet to be identified. We have determined, by Northern blot analysis, the abundance levels of several growth-regulated genes in SV40-transformed cell lines to determine if their expression is altered and correlates with the ability of SV40 transformed cells to grow in low serum containing media. The mRNA abundance levels of the G1-specific genes 2A9/calcyclin, 2F1/translocase, and 4F1/vimentin were determined in the parental hamster fibroblast cell line, tk-ts13, and in two SV40 transformants, HR5 and HR8 cells, grown in medium containing 10% calf serum (normal medium) and in HR5 and HR8 cells adapted to passage in medium containing low serum. A spontaneous transformant of the parental line capable of growth in low serum in the absence of SV40 transformation (tk-ts13/1%), was also included in these studies. The low serum adapted SV40-transformed cells and the spontaneous tk-ts13 transformed cells grew more vigorously than their nonadapted counterparts in medium containing low serum. The low serum adapted cells also grew to higher saturation densities in low serum and to densities comparable to those in high serum, whereas the nonadapted cells grew to low saturation densities in low serum, but not as low as the untransformed parental.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Identification of epidermal growth factor, transforming growth factor-alpha, and epidermal growth factor receptor in surgically induced endometriosis in rats.

The present immunohistochemical studies used polyclonal antibodies specific to epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and monoclonal antibodies to the extracellular binding domain of EGF receptor to elucidate their presence and cellular distribution in surgically induced endometriosis in the rat. Uterine segments were implanted in the mesenteric region adjacent to a blood vessel for a period of 4-6 weeks. During operative reexploration, the implanted tissues were intact, morphologically similar to the controls, and consisted of a cyst containing clear fluid and associated adhesion formation. All the uterine cell types immunostained with antibody to EGF. The highest immunostaining intensity was associated with inflammatory cells infiltrated among endometrial stromal cells, followed by luminal and glandular epithelial and stromal cells. The cysts consisted of an inner simple columnar epithelium, surrounded by several layers of smooth muscle and connective tissue. The cyst epithelial layer immunostained weakly, while the supporting wall stained moderately. The inflammatory cells found within the cyst cavity immunostained very intensely, comparable to those in the endometrium. The patterns of immunostaining for TGF-alpha and EGF receptor were similar to that observed for EGF. Myometrial smooth-muscle cells and endothelial and smooth-muscle cells of arterioles were also immunostained for EGF, TGF-alpha, and EGF receptor, but with lower intensity than that of the endometrium. These observations suggest that, like normal uterine tissue, endometrial implants produce EGF and TGF-alpha locally and contain receptors for EGF. These results imply a possible paracrine or autocrine role for growth factors in the establishment and/or maintenance of endometriotic tissue.

Animals↗
PubMed1990

Muscle-type MM creatine kinase is specifically bound to sarcoplasmic reticulum and can support Ca2+ uptake and regulate local ATP/ADP ratios.

Highly purified fractions of sarcoplasmic reticulum (SR) were prepared from chicken pectoralis muscles (Saito, A., Seiler, S., Chu, A., and Fleischer, S. (1984) J. Cell Biol. 99, 875-885) and analyzed for the presence of creatine kinase (CK). Vesicles derived from longitudinal SR contained 0.703 +/- 0.428 IU of CK/mg of (SR) protein. Immunogold localization of muscle-type MM-CK on ultrathin cryosections of muscle, after removal of soluble CK, revealed relatively strong in situ labeling of M-CK remaining bound to the M band as well as to the SR membranes. In addition, purified SR vesicles were also labeled by anti-M-CK antibodies, and the peripheral labeling was similar to that observed with anti-Ca2(+)-ATPase antibodies. Only some particulate CK enzyme was released from isolated SR membranes by EDTA/low salt buffer, and CK was resistant to extraction by 0.6 M KCl. Thus, some of the MM-CK present in muscle displays strong associative behavior to the SR membranes. The SR-bound CK was sufficient to support, in the presence of phosphocreatine plus ADP, a significant portion of the maximal in vitro Ca2+ uptake rate. The ATP regeneration potential of SR-bound CK was similar to the rate of Ca2(+)-stimulated ATP hydrolysis of isolated SR vesicles. Thus, CK bound to SR may be physiologically relevant in vivo for regeneration of ATP used by the Ca2(+)-ATPase, as well as for regulation of local ATP/ADP ratios in the proximity of the Ca2+ pump and of other ATP-requiring reactions in the excitation-contraction coupling pathway.

Adenosine Diphosphate↗
PubMed1990

Persistence of drug-induced chromosome aberrations in peripheral blood lymphocytes of the rat.

We have studied the persistence of pre-clastogenic lesions, detected as induced chromosomal aberrations, in rat peripheral lymphocytes at various time intervals after acute treatment with 3 different antineoplastic drugs: cyclophosphamide (CPA), 5-fluorouracil (5-FU) and adriamycin (AM). Single i.p. doses were administered to groups of rats and heart blood samples from each group were taken after 3, 12, 24 or 48 h or weekly up to 20 weeks later. The cytogenetic analysis was performed on lymphocytes cultured for 33 h after sampling. The results for CPA exposure (10 mg/kg) show that the yield of chromosome aberrations is maximal 3 h after the treatment (20 times the control level). For up to 8 weeks the values remain about 6 times the baseline; afterwards a decrease is observed and the control level is reached after 20 weeks. For 5-FU (50 mg/kg) a remarkable increase (13-fold) in chromosomal damage is observed at the first sampling time. Within 48 h the effect is drastically reduced but persistent (3 times the control level), and the level returns to spontaneous values 1 week later. AM treatment (2 mg/kg) induced an increase of about 8 times the control level at 3 h post exposure. The clastogenic effects remained at a detectable level for 1 week (about 6 times the control level at all sampling times); 2 weeks after the treatment the control level was found. A parallel analysis was performed on bone marrow cells. In this tissue the clastogenic effects of the treatments were maximal, as in lymphocytes, at the first sampling time (20-25 times the control level) and were no longer detectable within 72 h after exposure, irrespective of the administered drug.

Animals↗
PubMed1990

Mutations affecting RNA splicing in man are detected more frequently in somatic than in germ cells.

The spectrum of DNA sequence alterations in the hypoxanthine-guanine phosphoribosyltransferase (hprt) gene of HPRTase-deficient T-lymphocytes isolated from the blood of healthy male donors was determined and compared with the spectrum found in patients suffering from genetic diseases (Lesch-Nyhan syndrome or gouty arthritis) associated with a mutation in the same gene. Most of the T-cell mutants still produced hprt mRNA which was converted into cDNA and used for DNA sequence analysis after amplification using the polymerase chain reaction (PCR). In 39% of the 31 analyzed T-cell mutants of normal donors 1 or 2 exons were completely or partially deleted from hprt mRNA, probably because of a mutation in a splice acceptor site. Among patients suffering from the Lesch-Nyhan syndrome or gouty arthritis, the class of splice mutations amounts only to 7%. These data suggest that carriers of splice mutations often do not show the characteristics of HPRTase deficiency associated with these genetic diseases, because correctly spliced hprt mRNA is still produced at a low level.

Arthritis, Gouty↗
PubMed1990

Incidence of stress-related disorders among American and Brazilian men and women.

Cross-cultural differences in physical and emotional responses to stressors are reported in this study. Among professionals (e.g., managers, supervisors), the incidence of stress-related disorders can have remarkable impact upon organizational performance as well as personal well-being. In order to study the relationship of nationality and gender to stress-related disorders, 148 American and 180 Brazilian professionals completed a questionnaire asking them to identify their unique responses to occupational stressors. Statistical analysis indicated that significant differences exist between the responses based upon both nationality and gender. Specifically, Americans reported a significantly higher incidence of allergies and irritable bowel syndrome, while Brazilians reported a higher incidence of Raynaud's syndrome (major manifestations are cold hands/feet). The males reported a higher incidence of high blood pressure and TMJ dysfunction/bruxism (a major manifestation is teeth grinding), while the females reported a higher incidence of tension headaches. The results are discussed in comparison to other cross-cultural and cross-gender studies with similar outcomes.

Adult↗
PubMed1989

Dangerous behavior and changes in treatment course.

The association of dangerous behavior with the course of subsequent treatment was examined by comparing treatment courses of 45 severely mentally disabled patients identified as dangerous after an incident of dangerous behavior was noted in their clinical records with treatment courses of 122 severely mentally disabled patients who had no recorded incidents of dangerous behavior. The correlation of dangerousness with subsequent restrictiveness of treatment is clearly present in 6 of the 9 variables examined; the relationship generalizes across two rather different CMHC sites.

Adult↗
PubMed1989

Stressed at work. Identification of physiological responses to occupational stressors.

Past research has clearly outlined the negative physiological and psychological consequences of dysfunctional occupational stress. This investigation uses qualitative, self report techniques to determine professionals' physiological responses to occupational stress. The results indicate that physiological responses in the musculoskeletal system are the most prevalent and deserve further attention in future research.

Female↗
PubMed1988

Clastogenic effects induced in mice and rats by 1,4-bis[2-(3,5-dichloropyridyloxy)]-benzene, a phenobarbital-like enzyme inducer and liver tumour promoter.

The clastogenic activity of 1,4-bis[2-(3,5-dichloropyridyloxy)]-benzene (TCPOBOP), a phenobarbital-like enzyme inducer and liver tumour promoter, was studied in mammalian cells exposed in vivo and in vitro. The effects of an oral treatment with 3 mg/kg body weight of TCPOBOP were scored in the bone marrow cells and in the liver cells of B6C3F1 hybrid mice. A relevant increase in the frequency of chromosomal aberrations was observed in both cell types. A co-administration of TCPOBOP and carbon tetrachloride (the latter given to stimulate liver cell divisions) produced similar effects to those induced by TCPOBOP alone. Several i.p. doses (1, 3, 10, 30 or 100 mg/kg body weight) were administered to Swiss-albino mice and to Sprague-Dawley rats. In bone marrow cells, a remarkable concordance between the two species was observed: at any dose higher than 3 mg/kg body weight the increase in frequency of chromosomal aberrations was more than three times the control level, with a slight decrease at the highest dose. A dose of 300 mg/kg body weight was lethal. Doses of 3 or 30 mg/kg body weight were also administered i.p. to partially hepatectomized rats and the effects on metaphase chromosomes were detected in the liver cells. Besides an increase in structural chromosomal aberration frequency, TCPOBOP induced high percentages of hypodiploid and hyperdiploid-hypotetraploid liver cells. Since no changes in euploidy were observed in the bone marrow cells, this effect seems to be tissue specific. The clastogenic activity of TCPOBOP was also confirmed in vitro by a rat lymphocyte assay without addition of any exogenous metabolic activation.

Animals↗
PubMed1987

DNA synthesis, mitotic index, drug-metabolising systems and cytogenetic analysis in regenerating rat liver. Comparison with bone marrow test after 'in vivo' treatment with cyclophosphamide.

Rat-liver cells can be used to reveal "in vivo" clastogenic activity of indirect mutagens, provided that they are stimulated to divide by partial hepatectomy. In order to characterize the rat-liver metabolic capacity in such experimental conditions, several biochemical parameters were measured during the first 54-66 h of liver regeneration in Sprague-Dawley male rats, subjected to a partial hepatectomy. The levels of cytochrome P-450, the activities of styrene monooxygenase, epoxide hydrolase and glutathione-S-epoxide transferase were chosen as markers. All the enzymatic activities and the level of cytochrome P-450 decreased during the first 12 h after the hepatectomy to about 50% of the activities of the sham-operated rats considered as controls. Subsequent recovery of the metabolic capacity was not observed. DNA synthesis and the mitotic index were measured to find the most suitable time for metaphase analysis. DNA synthesis and the number of metaphases were maximal at, respectively, 22-25 and 28-31 h after partial removal of the liver. The sensitivity to clastogenic damage induced by "in vivo" treatment with cyclophosphamide (CPA) was assayed in regenerating liver cells by chromosome-aberration analysis. Different doses, ranging from 5 to 30 mg/kg b.w., were given i.p. to the rats 17 h before or 7 h after partial hepatectomy. Liver cells were collected 31 h after surgery. Clastogenic damage was greater when the drug was administered to the animals after the hepatectomy (24 h of exposure) than before (48 h of exposure). The sensitivity to CPA-induced damage was compared with a bone marrow cell test carried out on non-hepatectomized rats treated in the same way. The results indicated that in these conditions regenerating liver cells are more sensitive than bone marrow cells to the induction of chromosome aberrations by CPA.

Animals↗
PubMed1987

Innervation is required to stabilize and amplify creatine kinase activity in regenerated extensor digitorum longus muscles of rats.

Neural control of creatine kinase (CK, adenosine 5'-triphosphate creatine phosphotransferase: EC 2.7.3.2) was investigated by measuring enzymatic activity and isoenzymatic representation of CK in extensor digitorum longus (EDL) muscles of adult rats during and after regeneration. Experimental models were ischemized EDLs, reversibly or permanently denervated. Results showed that, during regeneration, CK in muscle fibers was likewise modified in both reversibly and permanently denervated EDLs. After regeneration a clear dichotomy was observed between the regenerated EDLs which were innervated and recovering CK activity, and those in which innervation was prevented and were rapidly losing activity. Further to investigate the neural influence on CK turnover, merely denervated age-matched EDLs were analysed and found to lose CK activity rapidly. The major conclusions are that during regeneration muscle CK is autonomously expressed, but following regeneration neural influence becomes an absolute requirement for stabilization and amplification of CK.

Animals↗
PubMed1986

Chromosome aberrations in rat liver cells and bone marrow cells following treatment in vivo with mitomycin C.

The clastogenic potential of mitomycin C (MMC) was studied in rat liver cells and bone marrow cells. Male Sprague-Dawley rats were partially hepatectomized and treated with a single i.p. dose of MMC (3.5 mg/kg body weight) 7 or 24 h after the operation. Non-hepatectomized rats were also treated with the same dose of MMC 7 or 24 h after the mutagenic treatment; liver and bone marrow cells were isolated from hepatectomized rats (31 h after the operation) and bone marrow cells only from non-hepatectomized animals. The results show that, if MMC was administered 7 h before the isolation of cells, the induction was more efficient in liver cells than in bone marrow cells. At this sampling time, there was no consistent difference between the frequencies observed in bone marrow cells from hepatectomized and non-hepatectomized rats. An increase was observed in both tissues 24 h after the mutagenic treatment. At this sampling time, the effect was significantly higher in the bone marrow cells from non-hepatectomized animals than in the liver cells and bone marrow cells from hepatectomized animals. No significant difference between the two cell types from hepatectomized rats was observed. Different factors related to the cytostatic properties of MMC and/or to cell kinetics in the two cell types, probably affected by the surgical operation, may account for the differences in the yield of chromosomal damage.

Animals↗
PubMed1986

Characteristics of psychiatric patients who engage in assaultive or other fear-inducing behaviors.

The hospital records of 1687 psychiatric patients were rated for the presence of assaultive or other fear-inducing behaviors associated with the reasons for their hospital admissions. Data analyses indicated that significant associations existed between these behaviors and sex, race/ethnicity, diagnosis, previous admissions, referral source for hospitalization, legal status at admission, and legal status at discharge. No associations were found for age, education, marital status, employment status, number of days hospitalized during the index hospitalization, and referral at discharge. A comparison of these results with the results of studies by other investigators led to the conclusion that clinical variables appear to have a more consistent relation to violent behavior than demographic variables. Future research examining for the correlates of violent behavior in psychiatric patients may be more productive by focusing on the type and degree of patients' psychopathologies rather than on patients' demographic characteristics.

Adolescent↗
PubMed1985

Violent or fear-inducing behavior associated with hospital admission.

Recent studies indicate that the incidence of violent or fear-inducing behavior among the mentally ill may be higher than once thought. In this study, medical record admission notes for 1,687 psychiatric patients over a four-year period were examined for indications that the patients had engaged in violent or fear-inducing behavior just prior to hospital admission. This and other studies suggest that the frequency of violent or fear-inducing behavior associated with psychiatric admissions may have stabilized in recent years. The authors also found a significantly higher level of hospital readmissions for violent patients than for other patients. As a result, they caution against assuming that the rate of violent behavior among hospital admissions accurately reflects the prevalence of violent behavior among the general population of the mentally ill.

California↗