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Biomedical subjects

M Steiner

Publications and source records attributed to M Steiner.

At least 73 records · Page 4Linked to original sources
PubMed1999

Antidepressant effect of ingested nicotine in female rats of Flinders resistant and sensitive lines.

Both major depression and depressive symptoms are associated with a high rate of nicotine dependence, and a history of major depression has an adverse impact on smoking cessation. The main objective of this study was to investigate whether continuous ingestion of nicotine affects indices of depressive behavior in the rat. We compared cholinergic- and serotonergic-hypersensitive Flinders Sensitive Line rats (FSL), a genetic animal model of depression, with their control counterparts, Flinders Resistant Line rats (FRL). Female rats of both lines were allowed access to a solution of nicotine bitartrate (100 microg/mL) in tap water for 14 days. Subsequent behavioral testing revealed striking effects of continuous ingestion of nicotine on depressive-like behavior of both lines. FSL and FRL rats that ingested nicotine for 14 days displayed less immobility in the 10-min forced-swim test (an index of depressive-like behavior) relative to the animals of both lines that were not exposed to nicotine or exposed to nicotine for shorter periods of time. This finding indicates that ingested nicotine has antidepressant properties that are independent of the genetic difference between FSL and FRL female rats. Animal studies on nicotine ingestion and withdrawal may become an important source of insights into the comorbidity of depression and nicotine self-administration.

Animals↗
PubMed1999

The measurement of premenstrual mood symptoms.

INTRODUCTION: To aid in the diagnosis and management of premenstrual syndromes, dozens of symptom measurement instruments have been created and several methods for classifying clinically important change in symptoms have been defined. While the diagnosis of premenstrual dysphoric disorder (PMDD) has become standardized through the application of research criteria, consensus amongst investigators as to the instruments best able to confirm the diagnosis and measure treatment effects has yet to be reached. OBJECTIVE: To determine the performance and inter-correlations of three prospective symptom rating scales used to establish severity of premenstrual mood symptoms and measure efficacy during a treatment trial for premenstrual dysphoria. METHODS: Single item visual analogue scales (VASs) for irritability, tension, depression and mood swings were used in combination with the Premenstrual Tension Syndrome Observer (PMTS-O) and Self-Rating (PMTS-SR) scales to measure the severity of premenstrual mood symptoms at baseline and during treatment. RESULTS: Premenstrual mood symptoms as measured by VASs significantly correlated with PMTS-0 and PMTS-SR scale scores (range 0.70 to 0.82, P < 0.001). All scales were sensitive to premenstrual symptom worsening (which is a required characteristic of this disorder) and revealed differences in effects of treatment on premenstrual mood symptoms (P < 0.001). CONCLUSIONS: VASs in combination with the PMTS-O are low in burden to the client, reliable, valid and sensitive to change. In light of the current debates regarding instruments most appropriate for the classification and measurement of treatment effects in women diagnosed with premenstrual dysphoria, further refinement of these scales is warranted.

Double-Blind Method↗
PubMed1999

Prevalence of dysthymic disorder in primary care.

BACKGROUND: Dysthymic disorder is characterised as a chronic state of depressed mood which is not otherwise attributable to physical, psychological or social events. While it can occur alone, there is increasing evidence that the majority of individuals who meet criteria for dysthymic disorder also experience more severe episodic mood disorders throughout their lifetime, and there is also an aggregation of mood disorders within their family members. Patients with dysthymic disorder are most often seen in primary care. Some researchers suggest that the majority of these individuals are never diagnosed or are not diagnosed until a more severe episodic mood disorder develops. The objective of this study was to determine the 12-month prevalence of Axis I psychiatric disorders, and in particular dysthymic disorder, in a primary care Health Service Organization in Ontario, Canada. METHODS: Eligible and consenting adults registered with a primary care Health Service Organization were screened using the modified form of the University of Michigan Composite International Diagnostic Interview. RESULTS: Of the 6280 eligible subjects, 4327 (69%) consented to screening. Two hundred and twenty-two (5.1%) subjects screened positive for dysthymic disorder. In addition, 90% of those who screened positive for dysthymic disorder also screened positive for other Axis I disorders including major depressive disorder, panic, simple phobia, and generalized anxiety disorder. CONCLUSIONS: There is much potential for the primary care physician to play a pivotal role in the recognition and treatment of dysthymic disorder and associated Axis I disorders. A focus on the family as a unit for care may be especially important given the reported aggregation of dysthymic disorder within families.

Adolescent↗
PubMed1999

Malignant tumors of Stensen's duct.

A rare case of squamous cell carcinoma arising in Stensen's duct is reported. The literature concerning malignant neoplasia originating in this site is reviewed, with attention given to the histopathologic diversity of neoplasms occurring in the duct, criteria for determination of origin in the duct, and outcomes of therapy.

Aged↗
PubMed1999

Is premenstrual dysphoric disorder a distinct clinical entity?

Does the evidence now available support the concept of premenstrual dysphoric disorder (PMDD) as a distinct clinical disorder such that the relative safety and efficacy of potential treatment can be evaluated? In a roundtable discussion of this question, a wealth of information was reviewed by a panel of experts. The key characteristics of PMDD, with clear onset and offset of symptoms closely linked to the menstrual cycle and the prominence of symptoms of anger, irritability, and internal tension, were contrasted with those of known mood and anxiety disorders. PMDD displays a distinct clinical picture that, in the absence of treatment, is remarkably stable from cycle to cycle and over time. Effective treatment of PMDD can be accomplished with serotinergic agents. At least 60% of patients respond to selective serotonin reuptake inhibitors (SSRIs). In comparison with other disorders, PMDD symptoms respond to low doses of SSRIs and to intermittent dosing. Normal functioning of the hypothalamic-pituitary-adrenal (HPA) axis, biologic characteristics generally related to the serotonin system, and a genetic component unrelated to major depression are further features of PMDD that separate it from other affective (mood) disorders. Based on this evidence, the consensus of the group was that PMDD is a distinct clinical entity. Potential treatments for this disorder can now be evaluated on this basis to meet the clear need for effective therapy.

Comorbidity↗
PubMed1999

Sustained complete remission after chemobiohormonal therapy for metastatic melanoma.

The combination of carmustine, cisplatin, dacarbazine, interferon, and low-dose tamoxifen is widely used in treating metastatic melanoma and was originally reported to achieve a 20% complete response rate. Among 29 patients who completed the authors' phase II study with the regimen, five (17%) achieved complete remission, and the median duration of response was 8 months (range, 2-14 months). The aim of the study was to evaluate briefly the value and toxicity of this regimen in treating metastatic malignant melanoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Immediate and late effects of coronary angiography on soluble endothelial cell markers and P-selectin in patients with and without coronary artery disease.

Endothelial cell injury and platelet activation are considered primary events in the pathogenesis of coronary artery disease (CAD) and are marked by plasma concentrations of von Willebrand factor (vWF) and soluble thrombomodulin, and by soluble P-selectin, respectively. Because both endothelial cells and platelets interact with contrast media, we aimed to detect immediate and 24-h changes in these markers following coronary angiography in patients with and without CAD. Sixteen patients with angiographically proven CAD and 14 patients without significant coronary stenosis were investigated. Blood samples were obtained from an antecubital vein before and 24 h after cardiac catheterization, and from the coronary sinus before and immediately after angiography. Concentrations of the markers were determined using enzyme-linked immunosorbent assays. In the coronary sinus samples, the only significant finding was an increase in levels of soluble P-selectin in the patients with CAD (P < 0.038). In the post-catheterization peripheral blood samples, concentrations of soluble P-selectin (P = 0.004), vWF (P = 0.0007) and soluble thrombomodulin (P = 0.0013) were all increased in patients with CAD. In contrast, patients without CAD demonstrated increased levels of vWF only (P = 0.0015) in peripheral blood samples obtained 24 h after angiography. We conclude that both immediate and 24-h changes take place in endothelial cells and platelet markers in response to cardiac catheterization, and that these changes are different in patients with angiographically proven CAD and in patients free of disease. These differences may reflect alterations in endothelial cell or platelet reactivity in patients with CAD.

Aged↗
PubMed1999

Vitamin E, a modifier of platelet function: rationale and use in cardiovascular and cerebrovascular disease.

Vitamin E has emerged as a major factor in the prevention and inhibition of cardiovascular disease. The inhibition of platelet function, especially adhesion, which is an important event in the development and propagation of cardiovascular disease, plays a crucial role in the beneficial effect that vitamin E exerts on such diseases. Although it is best known for its antioxidant activity, vitamin E interferes with platelet adhesion via a mechanism that is independent of this action. Vitamin E-induced inhibition of protein kinase C leads to decreased platelet pseudopodia formation upon stimulation by agonists, a process that is instrumental in reducing platelet adhesion. In conjunction with potent inhibitors of platelet aggregation, vitamin E has become a widely applied treatment regimen for this group of diseases. Increased bleeding, especially when vitamin E is combined with a potent platelet aggregation inhibitor, has to be considered a side effect of its mechanism of action, but should not detract from the potential benefits for the majority of patients who take this vitamin.

Aspirin↗
PubMed1999

An outline of graphical Markov models in dentistry.

BACKGROUND: In the usual multiple regression model there is one response variable and one block of several explanatory variables. In contrast, in reality there may be a block of several possibly interacting response variables one would like to explain. In addition, the explanatory variables may split into a sequence of several blocks, each block containing several interacting variables. The variables in the second block are explained by those in the first block; the variables in the third block by those in the first and the second block etc. OBJECTIVE AND METHODS: During recent years methods have been developed allowing analysis of problems where the data set has the above complex structure. The models involved are called graphical models or graphical Markov models. The main result of an analysis is a picture, a conditional independence graph with precise statistical meaning, consisting of circles representing variables and lines or arrows representing significant conditional associations. The absence of a line between two circles signifies that the corresponding two variables are independent conditional on the presence of other variables in the model. EXAMPLE: An example from epidemiology is presented in order to demonstrate application and use of the models. The data set in the example has a complex structure consisting of successive blocks: the variable in the first block is year of investigation; the variables in the second block are age and gender; the variables in the third block are indices of calculus, gingivitis and mutans streptococci and the final response variables in the fourth block are different indices of caries. Since the statistical methods may not be easily accessible to dentists, this article presents them in an introductory form. CONCLUSION: Graphical models may be of great value to dentists in allowing analysis and visualisation of complex structured multivariate data sets consisting of a sequence of blocks of interacting variables and, in particular, several possibly interacting responses in the final block.

Child↗
PubMed1998

[Taxol (paclitaxel) as second-line therapy in breast and ovarian cancer].

Results of chemotherapy with taxol (paclitaxel) in 55 patients with recurrent breast and ovarian cancer were reviewed. Taxol was given as a 3-hour infusion, every 3 weeks, on an outpatient basis. There was complete or partial response in 8 patients (23%) with breast cancer and 10 (50%) with ovarian cancer. Performance status and previous response to adriamycin were important prognostic factors. Toxicity was manageable. Treatment had to be stopped for hypersensitivity reactions in only 2 patients. Taxol given in an ambulatory clinic is safe and effective.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Glycoprotein VI is a major collagen receptor for platelet activation: it recognizes the platelet-activating quaternary structure of collagen, whereas CD36, glycoprotein IIb/IIIa, and von Willebrand factor do not.

Simple collagen-related peptides (CRPs) containing a repeat Gly-Pro-Hyp sequence are highly potent platelet agonists. Like collagen, they must exhibit tertiary (triple-helical) and quaternary (polymeric) structure to activate platelets. Platelet signaling events induced by the peptides are the same as most of those induced by collagen. The peptides do not recognize the alpha 2 beta 1 integrin. To identify the signaling receptor involved, we have evaluated the response to the CRP, Gly-Lys-Hyp(Gly-Pro-Hyp)10-Gly-Lys-Hyp-Gly of platelets with defined functional deficiencies. These studies exclude a primary recognition role for CD36, von Willebrand factor (vWF), or glycoprotein (GP) IIb/IIIa. Thus, both CD36 and vWF-deficient platelets exhibited normal aggregation, normal fibrinogen binding, and normal expression of CD62 and CD63, measured by flow cytometry, in response to the peptide, and there was normal expression of CD62 and CD63 on thrombasthenic platelets. In contrast, GPVI-deficient platelets were totally unresponsive to the peptide, indicating that this receptor recognizes the Gly-Pro-Hyp sequence in collagen. GPVI-deficient platelets showed some fibrinogen binding in response to collagen but failed to aggregate and to express CD62 and CD63. Collagen, but not CRP-XL, contains binding sites for alpha 2 beta 1. Therefore, it is possible that collagen still induces some signaling via alpha 2 beta 1, leading to activation of GPIIb/IIIa. Our findings are consistent with a two-site, two-step model of collagen interaction with platelets involving recognition of specific sequences in collagen by an adhesive receptor such as alpha 2 beta 1 to arrest platelets under flow and subsequent recognition of another specific collagen sequence by an activatory receptor, namely GPVI.

Binding Sites↗
PubMed1998

Genetically transmitted cholinergic hyperresponsiveness predisposes to experimental asthma.

The excitatory innervation of the airway smooth muscle is primarily cholinergic in nature. However, the potential neural mechanism(s) underlying airway hyperresponsiveness, one of the hallmarks of asthma, is not fully understood. In this study, cholinergic hyperresponsive Flinders sensitive line (FSL) rats and their control counterparts, Flinders resistant line (FRL) rats, were repeatedly challenged with different doses of nebulized methacholine (0, 4, 16, 64, and 256 mg/ml) for 5 min. Airway responsiveness was assessed in spontaneously breathing, unrestrained animals by means of whole body plethysmography. Increased airway responsiveness of FSL rats was evidenced as a more pronounced increase in Penh value (enhanced pause, an index of bronchoconstriction) across different concentrations of methacholine. In subsequent experiments, FSL and FRL rats were sensitized to ovalbumin and challenged with nebulized antigen. Our results indicate that the genetically transmitted cholinergic hyperresponsiveness of the FSL rat is paralleled by an increased susceptibility to allergen-induced bronchoconstriction and inflammation of the airways. This study provides further evidence that neural factors can play an important role in determining airway responsiveness and thus may be relevant for the expression of asthma. In addition, the FSL rat may be a useful model for studies of airway hyperresponsiveness.

Airway Obstruction↗
PubMed1998

The prostate anesthetic block for outpatient prostate surgery.

With the emergence of minimally invasive techniques for the treatment of benign prostate hyperplasia and the need to reduce health care costs, a simple and effective prostate anesthetic block may allow more procedures to be done in an outpatient or office setting. As based on neuroanatomy studies of the prostate, the perineal approach appeared to be the best way to anesthetize the prostate. This technique was used in 43 patients who underwent interstitial laser coagulation an outpatient or office setting. The perineal prostatic block was effective for pain control whether lidocaine or lidocaine/bupivacaine was used as determined by visual analog scale, linear pain scale, or global pain questionnaire. The use of intravenous (i.v.) sedation did not influence the efficacy of the prostate anesthetic block. Thus, the perineal prostate anesthetic block may be employed in patients undergoing minimally invasive surgery for benign prostatic hyperplasia in the outpatient/office location.

Aged↗
PubMed1998

Trends in infant leukaemia in West Germany in relation to in utero exposure due to Chernobyl accident.

A temporary increase in the incidence of infant leukaemia in Greece was reported by Petridou et al., which was attributed to in utero exposure to ionising radiation resulting from the Chernobyl accident. We performed a similar analysis based on the data of the German Childhood Cancer Registry in order to check whether the observation could be confirmed by means of independent data. Applying the same definitions as Petridou et al., we also observed an increased incidence of infant leukaemia in a cohort of children born after the Chernobyl accident. More detailed analyses, regarding areas with different contamination levels and dose rate gradients over time after the accident, showed, however, no clear trend with regard to exposure. It would therefore appear less likely that the observed effect was caused by exposure to ionising radiation due to the Chernobyl accident.

Child, Preschool↗
PubMed1998

Ribosomal gene transcription is organized in foci within nucleolar components.

We investigated how only three morphologically distinguished nucleolar components can integrate the many necessary tasks in ribosome biogenesis. For the mapping of ribosomal (r)DNA transcription loci, we combined non-autoradiographic in situ transcription assays with the immunological analysis of the ultrastructural distribution of transcription-associated proteins, i.e., polymerase I, the human polymerase I-specific upstream binding factor, and topoisomerase I. Furthermore, we visualized the nascent transcripts simultaneously with the rDNA in the nucleoli. All tested transcription proteins were found in both the fibrillar center and the dense fibrillar component (DF) of nucleoli in human cells. In the DF the nascent transcripts, detected by bromouridine incorporation, were found colocalized with the transcription proteins only within circumscribed regions. We did not observe colocalization of rDNA with nascent transcripts within the fibrillar centers, which corroborates the view that transcription proteins in this component are rather inactive. Our results suggests that only a minor portion of the DF is involved in transcriptional activity. Transcription appears to be confined to small foci, which exist close to or associated with the DF. Our results are in favor of the view that the DF has different functions which are localized in subcompartments of the DF.

Bromodeoxyuridine↗
PubMed1998

The use of heparinase to neutralize residual heparin in blood samples drawn through pediatric indwelling central venous catheters.

Routine-coagulation screening is unreliable if obtained through a previously heparinized central venous catheter. Screening tests were performed on 14 paired peripheral and central venous catheter samples without and with heparinase. The heparinase treated central venous catheter samples correlated well with the peripheral samples and can be used to atraumatically screen for hemostatic abnormalities.

Adolescent↗
PubMed1998

Changes in platelet function and susceptibility of lipoproteins to oxidation associated with administration of aged garlic extract.

Garlic and some of its organosulfur components have been found to be potent inhibitors of platelet aggregation in vitro. Demonstration of their efficacy in vivo, however, especially when administered over extended periods, is sparse. We recently performed a 10-month study comparing the effect of aged garlic extract (AGE) with placebo on the lipid profiles of moderately hypercholesterolemic men. In the course of the intervention trial, we examined platelet functions and susceptibility of lipoproteins to oxidation in a subgroup of this study population. Study subjects supplemented with 7.2 AGE per day showed a significant reduction of epinephrine- and, to a lesser degree, collagen-induced platelet aggregation but failed to demonstrate an inhibition of adenosine diphosphate (ADP)-induced aggregation. Platelet adhesion to fibrinogen, measured in a laminar flow chamber at moderately high shear rate, was reduced by approximately 30% in subjects taking AGE compared with placebo supplement. A trend toward decreased susceptibility of lipoproteins to oxidation also was noted during AGE administration compared with the placebo period. We conclude that the beneficial effect of garlic preparations on lipids and blood pressure extends also to platelet function, thus providing a wider potential protection of the cardiovascular system.

Adult↗