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Biomedical subjects

A Fein

Publications and source records attributed to A Fein.

At least 19 recordsLinked to original sources
PubMed2004

Diabetes teratogenicity is accompanied by alterations in macrophages and T cell subpopulations in the uterus and lymphoid organs.

Insulin-dependent diabetes mellitus is a well-known teratogen, which might cause growth retardation, malformations and fetal death. We have previously shown, that potentiation of the maternal immune system (immunopotentiation) might protect the embryo from diabetes teratogenicity. Therefore, in the present study we further inquired whether diabetes teratogenicity might be associated with alterations in the level of immune effector cells in systemic and local lymphoid organs as well as in the uterus throughout pregnancy and whether the protection exerted by maternal immunopotentiation might be realized through its effect on those cells. Streptozotocin-induced diabetes in ICR mice was found to reduce pregnancy rate and fetal weight while increasing the resorption rate and the percentage of litters with malformed fetuses. These teratogenic effects were accompanied by a decreased percentage of cells expressing Mac-1, Thy-1.2, CD4 or CD8 in the spleen and inguinal as well as paraaortic lymph nodes, except for Mac-1 expression by splenocytes, which increased significantly in the beginning of pregnancy and decreased later. A different pattern was observed in the uterus, when the percentage of cells expressing these markers tended to increase in the beginning of pregnancy and decrease later. Intrauterine immunopotentiation with rat splenocytes was found to improve the reproductive performance of diabetic animals. This protective effect was accompanied by a general normalization of the level of the various cell surface markers, when in most cases their expression returned to that found in nonimmunopotentiated mice. Our results suggest that the protection exerted by maternal immunopotentiation on the embryo against diabetes teratogenicity might be mediated via its effect on the level of immune effector cells localized to uterus and lymphoid organs, which was found to be altered in diabetic mice.

Animals↗
PubMed2003

TNF-alpha acts to prevent occurrence of malformed fetuses in diabetic mice.

AIMS/HYPOTHESIS: Activation of apoptosis in embryos is thought to be a key event in the pathogenesis of diabetes-induced embryopathies such as early embryonic death and inborn structural anomalies. TNF-alpha can activate apoptotic and anti-apoptotic signalling cascades, indicating its ability to contribute to and counteract diabetes-induced maldevelopment. To investigate how TNF-alpha regulates the response of embryos to diabetes-induced embryopathic stress, we used streptozotocin-induced diabetic TNF-alpha knockout mice. MATERIALS: To evaluate the reproductive performance, mated diabetic female mice were examined on days 4 and 8 of pregnancy for the presence of blastocysts or embryos in uterine horns. To evaluate the teratogenic effect, the female mice were killed on day 18 of pregnancy and fetuses were examined for gross external anomalies. In addition, apoptotic nuclei were localised by the TUNEL assay and DNA-binding activity of the transcription factor NF-kappaB was evaluated by electrophoretic mobility shift assay in 10- and 11-day-old embryos respectively. RESULTS: Severely diabetic TNF-alpha(+/+) female mice had a much greater decrease in pregnancy rate but a lower incidence of malformed fetuses in litters than severely diabetic TNF-alpha(-/-) female mice. Also, the intensity of excessive apoptosis was higher, but the amount of active NF-kappaB complexes was lower in malformed TNF-alpha(-/-) embryos than in TNF-alpha(+/+) embryos. CONCLUSIONS/INTERPRETATION: TNF-alpha contributes to death of peri-implantation embryos and possibly protects postimplantation embryos exposed to diabetes-induced teratogenic stimuli via activation of NF-kappaB-mediated anti-apoptotic signalling. It seems that TNF-alpha prevents the birth of malformed offspring in severely diabetic mice.

Animals↗
PubMed2003

TNF-alpha in pregnancy loss and embryo maldevelopment: a mediator of detrimental stimuli or a protector of the fetoplacental unit?

PURPOSE: Tumor necrosis factor alpha (TNF-alpha), a multifunctional cytokine, has been identified in the ovary, oviduct, uterus, and placenta, and is expressed in embryonic tissues. For many years TNF-alpha was mainly considered to be a cytokine involved in triggering immunological pregnancy loss and as a mediator of various embryopathic stresses. However, data collected during the last decade has characterized TNF-alpha not only as a powerful activator of apoptotic, but also antiapoptotic signaling cascades, as well as revealed its regulatory role in cell proliferation. This review summarizes and conceptualizes the studies addressing TNF-alpha-activated intracellular signaling and the possible functional role of TNF-alpha in embryonic development. METHODS: Studies addressing the role of TNF-alpha in intercellular signaling, in vivo studies addressing the functional role TNF-alpha in spontaneous and induced pregnancy loss, and studies addressing the role of TNF-alpha in fetal malformations were reviewed. Comparative studies in TNF-alpha knockout and TNF-alpha positive mice were performed to evaluate embryonic death, structural anomalies in fetuses, the degree of apoptosis and cell proliferation, and the activity of molecules such as caspases 3 and 8, the NF-kappaB, (RelA), IkappaBalpha in some target embryonic organs shortly after exposure to embryopathic stresses. RESULTS: It is proposed that the possible essential function of TNF-alpha may be to prevent the birth of offspring with structural anomalies. CONCLUSIONS: TNF-alpha will boost death signaling to kill the embryo if initial events (damages) triggered by detrimental stimuli may culminate in structural anomalies, and stimulate protective mechanisms if the repair of these damages may prevent maldevelopment.

Abortion, Spontaneous↗
PubMed2003

Increased TNF-alpha expression in cultured mouse embryos exposed to teratogenic concentrations of glucose.

Diabetes-induced early embryonic death is accompanied by an increased expression of tumour necrosis factor alpha (TNF-alpha) in the embryonic microenvironment. The aim of the present study was to evaluate whether diabetes-induced embryopathic stress may also alter the expression of TNF-alpha produced by the embryo itself. As a model, whole postimplantation embryos were cultured for 24 h in a medium with high concentrations of glucose, one of the main diabetes-associated teratogenic metabolites. An anomaly such as an open neural tube was used as an end-point characterizing the glucose-induced teratogenic effect and the number of somites was counted to evaluate growth retardation induced by glucose. The expression of TNF-alpha (by immunohistochemistry), apoptosis (by TdT-mediated dUTP nick-end labelling; TUNEL) and the activity of caspases 3 and 8 (by a fluorometric assay) were evaluated in normal and malformed embryos. Ninety-seven per cent of the embryos exposed to 1300 mg glucose dl(-1) exhibited an open neural tube. The percentage of malformed embryos was smaller in media containing 800 and 500 mg glucose dl(-1) (68 and 37%, respectively) but it still exceeded significantly the value registered in embryos developing in a normoglycaemic medium (12%). In addition, a significant decrease in the number of somites was observed in embryos developing in media containing 1300 and 800 mg glucose dl(-1). Malformed embryos exhibited a greater number of nuclei that were positive in the TUNEL assay as well as a higher amount of active caspase 8 compared with normal embryos (with closed neural folds). TNF-alpha expression was detected in the neuroepithelial layer of the neural tube of the malformed embryos, whereas the expression of this cytokine was weak, if detectable, in normal embryos. Together, these findings indicate that TNF-alpha produced by the embryo may be involved in regulating the response of embryos to diabetes-generated embryopathic stress.

Abnormalities, Drug-Induced↗
PubMed2002

Diabetes teratogenicity in mice is accompanied with distorted expression of TGF-beta2 in the uterus.

Early embryonic deaths as well as malformed newborns are among complications of the diabetic pregnancy. Cytokines and growth factors operating in the embryonic vicinity are found to be among factors that determine the sensitivity of embryos to external and internal detrimental stimuli, including diabetes. Transforming Growth Factor-beta2 (TGF-beta2) has been shown to be essential for embryonic development and survival. In the present work, we evaluated the pattern of TGF-beta2 expression in the uterus of streptozotocin-induced diabetic mice, demonstrating a decreased reproductive performance and elevated percentage of litters with severely malformed fetuses. Since stimulation of the maternal immune system was found to increase the resistance of mouse embryos to the teratogenic effect of diabetes, the effect of immunopotentiation on the expression of the cytokine was also investigated. TGF-beta2 expression was studied at the mRNA level by using the in situ hybridization technique and at the protein level by using the immunohistochemical analysis. A clear decrease in TGF-beta2 mRNA expression in the uterus of diabetic mice was observed at examined time points: days 1, 5, and 9 of pregnancy. Also, an evident reduction in TGF-beta2, the protein expression in the uterus of diabetic mice, was demonstrated at these time points. Maternal immunopotentiation that improved the reproductive performance of diabetic mice and reduced the number of the litters with malformed fetuses was also accompanied by a clear increase in the level of TGF-beta2 mRNA expression in the pregnant uteri. The above results clearly demonstrate that the embryotoxic effect of diabetes is accompanied by an alteration of TGF-beta2 expression. Immunopotentiation that was shown to improve the reproductive performance of the diabetic mice was accompanied by a partial normalization of TGF-beta2 expression in embryonic vicinity.

Animals↗
PubMed2002

The role of pro- and anti-apoptotic molecular interactions in embryonic maldevelopment.

PROBLEM: Pregnancy loss and the occurrence of inborn structural anomalies are often preceded by excessive apoptosis in targeted embryonic and extraembryonic tissues. Apoptogenic stimuli activate both death and survival, signaling cascades consisting of molecules acting as activators and effectors, or negative regulators of apoptosis. The interplay between these cascades determines whether the cell which is exposed to an apoptogenic stimulus dies or survives. This review summarizes the functioning of pro- and anti-apoptotic molecules in embryos responding to various teratogens. The effect of potentiation of the maternal immune system on these molecules is also discussed. METHODS OF STUDY: The data on the functioning of various pro- and anti-apoptotic molecules in embryos exposed to various developmental toxicants, and embryos developing in a diabetic environment are reviewed. Techniques such as the TUNEL method, DNA fragmentation assay, electromobility shift assay (EMSA), fluorometric assay, immunohistochemistry, Western blot, In situ hybridization, have been used in our studies to detect apoptosis, and evaluate the functioning of molecules such as TNFalpha, caspases, NF-kappaB and IkappaB, p53, and bcl-2 in different embryonic and extraembryonic tissues. RESULTS: Our and other data summarized in this review have demonstrated that the doses of developmental toxicants required to induce pregnancy loss and gross structural anomalies induce excessive apoptosis shortly after treatment. Depending on the intensity and type of targeted tissues, this apoptosis was accompanied by alterations in the activity of the molecules which act as activators and effectors (e.g. caspase 3, caspase 8, caspase 2, p53) or negative regulators (bcl-2, NF-kappaB) of apoptosis. Maternal immunopotentiation, which decreases the level of induced and spontaneous pregnancy loss and the incidence and severity of teratogen-induced structural anomalies has been shown to modulate the expression of these molecules both in embryonic tissues and at the feto-maternal interface. CONCLUSIONS: The data presented in this review suggest that molecules such as TNFalpha, caspase 3, caspase 8, NF-kappaB, p53 and bcl-2, which are involved in the regulation of apoptosis, may also be involved in determining the sensitivity of the embryo to developmental toxicants. Maternal immunopotentiation may modulate the functioning of these molecules.

Animals↗
PubMed2002

Apoptosis in the uterus of mice with pregnancy loss.

PROBLEM: The mechanisms mediating pregnancy loss induced by various agents are far from being understood. Thus, we investigated the possible involvement of one such mechanism, the apoptotic process, in pregnancy loss induced by lipopolysaccharide (LPS) or cyclophosphamide (CP) as well as the associated changes in the apoptosis-regulating gene products p53 and bcl-2. METHOD OF STUDY: Pregnancy loss was induced by LPS or CP on days 9 or 12 of pregnancy, respectively. LPS- or CP-associated apoptosis was assessed by the TdT mediated dUTP-biotin nick end labeling (TUNEL) method as well as by DNA fragmentation analysis, while p53 or bcl-2 expression was evaluated by immunohistochemistry. RESULTS: Lipopolysaccharide treatment initiated a resorption process that was accompanied by the appearance of apoptotic cells in the uterus, which increased in number by 24 hr after treatment. Induction of pregnancy loss with CP resulted in the appearance of some apoptotic cells in the uterus, reaching a peak at 72 hr after treatment. DNA fragmentation analysis revealed a DNA ladder at 24 hr after LPS as well as 72 hr after CP treatment. Immunohistochemical analysis demonstrated a continuous p53 expression in the uterus of LPS- or CP-treated mice, which was somewhat elevated at the peak of the apoptotic process. On the other hand, bcl-2 expression in LPS-treated mice could be reciprocally correlated with the apoptotic process, appearing only at its initiation or completion, while in CP-treated mice it was continuously expressed except for some elevation at the completion of the apoptotic process. CONCLUSIONS: Our results suggest a possible role for the apoptotic process in mechanisms mediating pregnancy loss and indicate an involvement of p53 and bcl-2 in its regulation.

Abortion, Spontaneous↗
PubMed2002

Cytokine expression in the uterus of mice with pregnancy loss: effect of maternal immunopotentiation with GM-CSF.

It is believed that failure of the maternal immune system to actively support embryonic development, through production of the appropriate cytokine network, might be responsible for embryonic death. Thus, the aim of this study was to evaluate the possible involvement of cytokines such as tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta2 (TGF-beta2), which are crucial for normal embryonic development, in the early stages of mechanisms that mediate induced pregnancy loss. The early stages of the resorption process induced by lipopolysaccharide (LPS) were characterized by blood accumulation in the vicinity of the embryo, preceding any visible embryonic damage. At that time, immunohistochemical analysis revealed an increased expression of TNF-alpha in the primary and secondary decidua, which was reduced as the resorption process was completed. In contrast, TGF-beta2 expression was decreased in the primary and secondary decidua, as well as in the glandular epithelium, at all the times assessed. Maternal immunopotentiation with granulocyte macrophage-colony stimulating factor (GM-CSF), which controls maternal immune activities supporting normal embryonic development, decreased the resorption rate in LPS-treated mice while normalizing the expression of TNF-alpha and TGF-beta2 in the uterus of these animals throughout the ongoing resorption process. These results indicate a possible role for maternal immunopotentiation with GM-CSF in the mechanisms mediating the early stages of pregnancy loss, possibly via modulation of TNF-alpha and TGF-beta2 activity.

Abortion, Spontaneous↗
PubMed2001

Hormones, cytokines and fetal anomalies in habitual abortion.

Recurrent miscarriage may be due to an inherently abnormal embryo (e.g. chromosomal aberrations), or maternal factors (e.g. uterine anomalies or antiphospholipid antibodies). However, there may be another mechanism; fetuses may have anomalies induced by toxic maternal factors. Early ultrasound scanning has revealed structural anomalies in karyotypically normal embryos in pregnancies that have terminated in first-trimester missed abortion. The serum of recurrently miscarrying women is toxic to blastocysts, embryos and fetuses. Teratogens such as cyclophosphamide or toxins such as lipopolysaccharide cause fetal demise by excessive apoptosis. Excessive apoptosis may be mediated by tumor necrosis factor-alpha and other cytokines. Both immunomodulation and hormonal support (progesterone or human chorionic gonadotropin supplements) have been used to improve the live birth rate in recurrently aborting women. Each may modulate the balance between Th1 and Th2 cytokines. Th2 cytokines are thought to benefit the developing embryo by enhancing placental growth and function, and possibly by preventing inappropriate apoptosis. Although neither hormonal support nor immunopotentiation have proved to be beneficial, no trial has limited itself to pregnancies that are karyotypically normal. This review assesses fetal structural anomalies in humans and laboratory animals as causes of pregnancy loss, the role of cytokines in those anomalies and the role of immunomodulation and hormones in modifying these effects.

Abortion, Habitual↗
PubMed2001

TGFbeta2 in embryos with inborn anomalies: effect of maternal immunopotentiation.

PROBLEM: TGFbetas are among the main immunoregulatory molecules contributing to successful embryonic development. Besides, our and other studies revealed that maternal immunopotentiation has a potential to increase the resistance of the embryo to the teratogenic insult. This work was designed to evaluate: (1) whether the formation of teratogen-induced anomalies is accompanied by an altered pattern of TGFbeta2 expression in embryonic cells and (2) whether maternal immunopotentiation modifies the pattern of TGFbeta2 expression in embryos responding to the teratogenic insult. METHOD OF STUDY: Experiments were performed in embryos of ICR mice exposed to 15 and 40 mg/kg of a reference teratogen, cyclophosphamide (CP) on day 12 of gestation. A group of mice was immunopotentiated with xenogeneic rat splenocytes 21 hr before the beginning of mating. Embryos were examined for the occurrence of gross structural anomalies 24 and 72 hr after CP treatment. Then, immunohistohemistry and in situ hybrydization assays were used to evaluate the expression of TGFbeta2 protein and mRNA in the brain, face, limbs and liver of these embryos. RESULTS: No external anomalies were observed in embryos examined 24 hr after CP treatment. Embryos examined 72 hr after CP treatment at 40 mg/kg exhibited agnathia, micrognathia, kinky tail, phocomelia, but no signs of dismorphogenesis were observed in the liver at the organ level. A significant increase in the expression of TGFbeta2 mRNA was observed in cells, residing in the brain, face and limbs but not in the liver of CP-exposed embryos tested 24 hr after CP injection in both doses. The level of TGFbeta2 protein in these embryos did not differ from that of controls. In embryos tested 72 hr after CP injection in the high dose both TGFbeta2 protein and mRNA expression were found to be elevated. Maternal immunopotentiation while enhancing the embryo's resistance to CP practically abolished an elevated expression of the TGFbeta2 mRNA detected in tested organ structures of embryos of non-immunopotentiated CP treated mice 24 hr after CP injection in both the low and the high doses. Also, a significant decrease in the level of TGFbeta2 mRNA expression was observed in embryos of immunopotentiated mice examined 72 hr after CP treatment. CONCLUSIONS: The results of this work show a possible involvement of TGFbeta2 in the formation of teratogen-induced structural anomalies and suggest that the stimulation of the maternal immune system may realize its protective effect by normalizing the level of TGFbeta2 expression in teratogen-targeted embryonic structures.

Abnormalities, Drug-Induced↗
PubMed2000

Cloning of human Ca2+ homoeostasis endoplasmic reticulum protein (CHERP): regulated expression of antisense cDNA depletes CHERP, inhibits intracellular Ca2+ mobilization and decreases cell proliferation.

A monoclonal antibody which blocks InsP(3)-induced Ca(2+) release from isolated endoplasmic reticulum was used to isolate a novel 4.0 kb cDNA from a human erythroleukaemia (HEL) cell cDNA expression library. A corresponding mRNA transcript of approx. 4.2 kb was present in all human cell lines and tissues examined, but cardiac and skeletal muscle had an additional transcript of 6.4 kb. The identification in GenBank(R) of homologous expressed sequence tags from many tissues and organisms suggests that the gene is ubiquitously expressed in higher eukaryotes. The gene was mapped to human chromosome 19p13.1. The cDNA predicts a 100 kDa protein, designated Ca(2+) homoeostasis endoplasmic reticulum protein (CHERP), with two putative transmembrane domains, multiple consensus phosphorylation sites, a polyglutamine tract of 12 repeats and regions of imperfect tryptophan and histadine octa- and nona-peptide repeats. In vitro translation of the full-length cDNA produced proteins of M(r) 128000 and 100000, corresponding to protein bands detected by Western blotting of many cell types. CHERP was co-localized in HEL cells with the InsP(3) receptor by two-colour immunofluorescence. Transfection of HEL cells with antisense cDNA led to an 80% decline in CHERP within 5 days of antisense induction, with markedly decreased intracellular Ca(2+) mobilization by thrombin, decreased DNA synthesis and growth arrest, indicating that the protein has an important function in Ca(2+) homoeostasis, growth and proliferation.

Amino Acid Sequence↗
PubMed2000

Emerging trends in ICU management and staffing.

It is likely that greater on-site intensivist coverage in critical care units will be observed in the future. Regionalization of critical care services will make this a financial reality because this level of expertise cannot realistically be provided to all hospitals. Perhaps units above a certain size will warrant this level of coverage and smaller community hospitals will transfer patients in need of a very high level of service, which can be provided only by intensivists on site. Community hospitals may rely on specially trained nurse practitioners or physician assistants to provide more on-site coverage during off hours. As technology advances, telemedicine will play a greater role in providing intensivist coverage to ICUs during off hours or to community hospitals in remote areas. Advanced technology and reorganization of critical care services offer opportunities for creative and nontraditional ways to deliver improved care to patients.

Humans↗
PubMed2000

Other modalities of oxygen therapy: hyperbaric oxygen, nitric oxide, and ECMO.

Novel therapies for the next decade include hyperbaric oxygen, nitric oxide, and extracorporeal membrane oxygenation. Hyperbaric oxygen delivers oxygen at a pressure greater than one atmosphere and has been used in diseases ranging from decompression sickness to carbon monoxide poisoning. Inhaled nitric oxide, a potent vasodilator, has been used in the acute respiratory distress syndrome and for the diagnosis and treatment of pulmonary hypertension. Extracorporeal membrane oxygenation (ECMO) has been used to provide cardiopulmonary bypass support, particularly in the pediatric and neonatal population.

Administration, Inhalation↗
PubMed2000

Dual regulation of calcium mobilization by inositol 1,4, 5-trisphosphate in a living cell.

Changes in cytosolic free calcium ([Ca(2+)](i)) often take the form of a sustained response or repetitive oscillations. The frequency and amplitude of [Ca(2+)](i) oscillations are essential for the selective stimulation of gene expression and for enzyme activation. However, the mechanism that determines whether [Ca(2+)](i) oscillates at a particular frequency or becomes a sustained response is poorly understood. We find that [Ca(2+)](i) oscillations in rat megakaryocytes, as in other cells, results from a Ca(2+)-dependent inhibition of inositol 1,4,5-trisphosphate (IP(3))-induced Ca(2+) release. Moreover, we find that this inhibition becomes progressively less effective with higher IP(3) concentrations. We suggest that disinhibition, by increasing IP(3) concentration, of Ca(2+)-dependent inhibition is a common mechanism for the regulation of [Ca(2+)](i) oscillations in cells containing IP(3)-sensitive Ca(2+) stores.

Adenosine Diphosphate↗
PubMed2000

Management of acute exacerbations in chronic obstructive pulmonary disease.

An acute exacerbation of chronic obstructive pulmonary disease (COPD) is characterized by an acute worsening of symptoms accompanied by lung infection. In severe cases, an acute exacerbation may cause respiratory failure and death. Successful management of acute exacerbation of COPD in either the inpatient or outpatient setting requires attention to a number of key issues. In this review, issues regarding the management of acute exacerbations of COPD are discussed. An inhaled beta-2 agonist along with the inhaled anticholinergic bronchodilator are recommended. Antibiotic therapy has been demonstrated to improve clinical recovery and physical outcomes. It should be directed against the most commonly occurring pathogens and, in more severe cases, coverage against Gram-negative bacteria is considered. Short course of systemic steroids does provide benefit in hospitalized patients. Supplemental oxygen is appropriate for all patients with hypoxemia. Ventilatory support treatment may be necessary, noninvasive ventilatory assistance being preferable early in the course of the acute episode. In a high number of cases, endotracheal intubation may be avoided. Promoting smoking cessation and the use of influenzae and pneumococcal vaccination may help decrease frequency of episodes of these exacerbations.

Administration, Inhalation↗