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1.
Eur J Clin Nutr ; 71(12): 1449-1454, 2017 12.
Article in English | MEDLINE | ID: mdl-28901336

ABSTRACT

BACKGROUND/OBJECTIVES: Vitamin D and probiotics are nutrients of interest in the context of type 1 diabetes (T1D). We assessed the prevalence of and factors associated with vitamin D and probiotic supplementations among young children with genetic risk of T1D. SUBJECTS/METHODS: Use of supplements during the first 2 years of life was collected prospectively from 8674 children in The Environmental Determinants of Diabetes in the Young (TEDDY) study. RESULTS: Single and/or multivitamin/mineral (MVM) supplements were reported by 81% of the children. The majority of participants in Finland, Germany and Sweden (97-99%) and 50% in the United States received vitamin D supplements that were mostly MVMs. Probiotics use varied from 6% in the United States to 60% in Finland and was primarily from probiotics-only preparations. More than 80% of the vitamin D and probiotics supplementation was initiated during infancy, and more than half of the uses lasted longer than a year. Being the first child, longer duration of breastfeeding, born in a later year, older maternal age and higher maternal education level were associated with both vitamin D and probiotics use. Shorter gestational age and mother not smoking during pregnancy were associated with a higher likelihood of probiotics supplementation only. CONCLUSIONS: Vitamin D and probiotics supplementations are popular in children 0-2 years old and are associated with common factors. Data documented here will allow evaluation of the relationship between early childhood dietary intake and the development of islet autoimmunity and progression to T1D.


Subject(s)
Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/prevention & control , Dietary Supplements , Genetic Predisposition to Disease , Probiotics/administration & dosage , Vitamin D/administration & dosage , Adult , Birth Weight , Child, Preschool , Diabetes Mellitus, Type 1/blood , Female , Finland , Germany , Humans , Infant , Male , Micronutrients/administration & dosage , Micronutrients/blood , Prospective Studies , Risk Factors , Surveys and Questionnaires , Sweden , United States , Vitamin D/blood , Young Adult
2.
Arch Gen Psychiatry ; 57(10): 968-76, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11015815

ABSTRACT

BACKGROUND: Patients with Alzheimer disease (AD) commonly exhibit psychosis and behavioral disturbances that impair patient functioning, create caregiver distress, and lead to institutionalization. This study was conducted to assess the efficacy and safety of olanzapine in treating psychosis and/or agitation/aggression in patients with AD. METHODS: A multicenter, double-blind, placebo-controlled, 6-week study was conducted in 206 elderly US nursing home residents with AD who exhibited psychotic and/or behavioral symptoms. Patients were randomly assigned to placebo or a fixed dose of 5, 10, or 15 mg/d of olanzapine. The primary efficacy measure was the sum of the Agitation/Aggression, Hallucinations, and Delusions items (Core Total) of the Neuropsychiatric Inventory-Nursing Home version. RESULTS: Low-dose olanzapine (5 and 10 mg/d) produced significant improvement compared with placebo on the Core Total (-7.6 vs -3.7 [P<.001] and -6.1 vs -3. 7 [P =.006], respectively). Core Total improvement with olanzapine, 15 mg/d, was not significantly greater than placebo. The Occupational Disruptiveness score, reflecting the impact of patients' psychosis and behavioral disturbances on the caregiver, was significantly reduced in the 5-mg/d olanzapine group compared with placebo (-2.7 vs -1.5; P =.008). Somnolence was significantly more common among patients receiving olanzapine (25.0%-35.8%), and gait disturbance occurred in those receiving 5 or 15 mg/d (19.6% and 17.0%, respectively). No significant cognitive impairment, increase in extrapyramidal symptoms, or central anticholinergic effects were found at any olanzapine dose relative to placebo. CONCLUSION: Low-dose olanzapine (5 and 10 mg/d) was significantly superior to placebo and well tolerated in treating agitation/aggression and psychosis in this population of patients with AD.


Subject(s)
Alzheimer Disease/drug therapy , Antipsychotic Agents/therapeutic use , Behavioral Symptoms/drug therapy , Nursing Homes , Pirenzepine/analogs & derivatives , Pirenzepine/therapeutic use , Psychotic Disorders/drug therapy , Aged , Aged, 80 and over , Alzheimer Disease/psychology , Behavioral Symptoms/psychology , Benzodiazepines , Double-Blind Method , Drug Administration Schedule , Female , Humans , Male , Middle Aged , Olanzapine , Placebos , Psychotic Disorders/psychology , Treatment Outcome
3.
Stat Med ; 19(16): 2169-84, 2000 Aug 30.
Article in English | MEDLINE | ID: mdl-10931518

ABSTRACT

Currently available antidepressants have a delayed onset of action and there is considerable interest in developing new products which exhibit a shorter time to response. Previous authors have suggested using a cure model to characterize the time to response for the combination of the patients who respond and the patients who do not respond. In this paper, we use the cure model and propose a Cramer-von Mises statistic to compare the time to response distributions for patients who respond to therapy. The asymptotic null distribution of the statistic is derived. A bootstap procedure is also proposed for sample sizes typical in antidepressant clinical trials. Results of the simulation study suggest that for common designs and sample sizes used in such trials, the statistic has reasonable size and power properties as long as censoring is moderate.


Subject(s)
Adrenergic beta-Antagonists/administration & dosage , Antidepressive Agents, Second-Generation/administration & dosage , Antidepressive Agents/administration & dosage , Clinical Trials as Topic/statistics & numerical data , Depressive Disorder/drug therapy , Fluoxetine/administration & dosage , Models, Statistical , Pindolol/administration & dosage , Algorithms , Humans , Sample Size , Statistical Distributions , Survival Analysis , Time Factors , Treatment Outcome
4.
J Clin Psychiatry ; 60(6): 389-94, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10401918

ABSTRACT

BACKGROUND: Although a period of 6 to 12 months of antidepressant therapy is recommended for most patients with depression, systematic examinations of the course of adverse events over time, the resolution of early-onset events, and the possible emergence of later-onset events are limited. We examined the safety of fluoxetine, 20 mg/day, in a large, prospective, long-term treatment trial, and we report a comparison of early- and late-onset adverse events and the course of adverse events over 26 weeks of treatment. METHOD: Adverse events were recorded at each visit in a uniform format by open-ended questioning, regardless of perceived causality. New or worsened events reported in either the first 4 weeks of treatment (early-reporting interval) or weeks 22 through 26 of treatment (late-reporting interval) were compared. RESULTS: Patients (N = 299) whose depression (DSM-III-R) remitted with 12 weeks of fluoxetine treatment entered continuation therapy, and 174 completed 26 weeks of therapy. All events that occurred in > or =5% of patients early in treatment decreased in frequency over time (p<.05), and no events occurred significantly more frequently during continuation therapy. No previously uncommon adverse events became common during long-term treatment. CONCLUSION: Common adverse events associated with initiating fluoxetine treatment in depressed patients, including nausea, insomnia, nervousness, and somnolence, resolve in the majority of patients and become significantly less frequent with continued treatment over a 6-month period. No adverse events present initially become more frequent late in treatment. Therapy with fluoxetine, 20 mg/day, is well tolerated over 6 months, and most adverse events observed early in treatment resolve.


Subject(s)
Depressive Disorder/drug therapy , Fluoxetine/adverse effects , Selective Serotonin Reuptake Inhibitors/adverse effects , Anxiety/chemically induced , Anxiety/epidemiology , Depressive Disorder/psychology , Double-Blind Method , Drug Administration Schedule , Fluoxetine/therapeutic use , Follow-Up Studies , Headache/chemically induced , Headache/epidemiology , Humans , Nausea/chemically induced , Nausea/epidemiology , Placebos , Secondary Prevention , Selective Serotonin Reuptake Inhibitors/therapeutic use , Sleep Initiation and Maintenance Disorders/chemically induced , Sleep Initiation and Maintenance Disorders/epidemiology , Sleep Stages , Surveys and Questionnaires , Treatment Outcome
5.
Br J Psychiatry ; 174: 23-30, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10211147

ABSTRACT

BACKGROUND: Tardive dyskinesia is important in the side-effect profile of antipsychotic medication. AIMS: The development of tardive dyskinesia was evaluated in patients treated with double-blind, randomly assigned olanzapine or haloperidol for up to 2.6 years. METHODS: Tardive dyskinesia was assessed by the Abnormal Involuntary Movement Scale (AIMS) and Research Diagnostic Criteria for Tardive Dyskinesia (RD-TD), it was defined as meeting RD-TD criteria at two consecutive assessments. The risk of tardive dyskinesia, the relative risk, incidence rate, and incidence rate ratio were estimated. RESULTS: The relative risk of tardive dyskinesia for the overall follow up period for haloperidol (n = 522) v. olanzapine (n = 1192) was 2.66 (95% CI = 1.50-4.70). Based on data following the initial six weeks of observation (during which patients underwent medication change and AIMS assessments as frequently as every three days), the one-year risk was 0.52% with olanzapine (n = 513) and 7.45% with haloperidol (n = 114). The relative risk throughout this follow-up period was 11.37 (95% CI = 2.21-58.60). CONCLUSION: Our results indicated a significantly lower risk of tardive dyskinesia with olanzapine than with haloperidol.


Subject(s)
Antipsychotic Agents/adverse effects , Dyskinesia, Drug-Induced/etiology , Haloperidol/adverse effects , Pirenzepine/analogs & derivatives , Schizophrenia/drug therapy , Benzodiazepines , Double-Blind Method , Humans , Olanzapine , Pirenzepine/adverse effects , Risk Factors , Survival Analysis
6.
Am J Psychiatry ; 155(11): 1570-7, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9812120

ABSTRACT

OBJECTIVE: Although panic attacks account for only a portion of the morbidity of panic disorder and panic attack frequency assessments are unreliable, studies of drug efficacy in panic disorder have generally used reduction in panic attack frequency as the primary measure of improvement. The authors studied the efficacy of fluoxetine treatment in panic disorder and measured the relative contributions of changes in symptoms to overall improvement. METHOD: Patients with a diagnosis of panic disorder (N = 243) were randomly assigned to treatment with 10 or 20 mg/day of fluoxetine or placebo. Primary outcome measures were change in panic attack frequency and clinician-rated Clinical Global Impression improvement scores. Other assessments included a panic attack inventory, clinician-rated and patient-rated versions of the Panic and Phobic Disorder Change Scale, a phobia rating scale, the Hamilton Anxiety Rating Scale, the 21-item Hamilton Depression Rating Scale, and the Sheehan Disability Scale. Correlations were determined between outcomes in individual symptom domains and overall clinical outcome. RESULTS: Fluoxetine, particularly the 20-mg/day dose, was associated with more improvement than was placebo in patients with panic disorder across multiple symptom measures, including global improvement, total panic attack frequency, phobic symptoms, and functional impairment. Global improvement was most highly correlated with reductions in overall anxiety and phobic symptoms and least correlated with reduction in panic attacks. Fluoxetine treatment for panic disorder was well tolerated, with a safety profile consistent with that observed for fluoxetine in other disorders. CONCLUSIONS: These data provide support for the efficacy and safety of fluoxetine treatment in reducing panic attacks, phobic symptoms, anxiety, and depressive symptoms in patients with panic disorder. Reductions in panic attack frequency in subjects given either fluoxetine or placebo were less closely related to overall clinical improvement than reductions in phobic avoidance, anxiety, depressive symptoms, and functional impairment, suggesting that outcome measures in this disorder should be more broadly based.


Subject(s)
Fluoxetine/therapeutic use , Panic Disorder/drug therapy , Adult , Dose-Response Relationship, Drug , Drug Administration Schedule , Female , Humans , Male , Middle Aged , Outcome Assessment, Health Care , Panic Disorder/diagnosis , Panic Disorder/psychology , Personality Inventory , Placebos , Psychiatric Status Rating Scales/statistics & numerical data , Severity of Illness Index , Treatment Outcome
7.
J Biopharm Stat ; 8(1): 55-67, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9547427

ABSTRACT

In this paper, an exact test for analyzing the homogeneity of treatment effect in adaptive multicenter clinical trials is proposed. Extensive simulation studies are performed to investigate the large sample behavior of a commonly used test statistic for testing homogeneity of treatment effect. When the sample size in each center is large relative to the number of centers, the asymptotic null distribution of the test statistic is reasonable. On the other hand, when the data are relatively sparse, the proposed exact test should be used to incorporate the adaptive nature of the design.


Subject(s)
Multicenter Studies as Topic/statistics & numerical data , Research Design/statistics & numerical data , Algorithms , Computer Simulation , Data Interpretation, Statistical , Sample Size
8.
Am J Psychiatry ; 154(9): 1248-54, 1997 Sep.
Article in English | MEDLINE | ID: mdl-9286184

ABSTRACT

OBJECTIVE: Tardive dyskinesia is a serious and common complication of neuroleptic treatment. Olanzapine is a novel antipsychotic agent exhibiting regional mesolimbic dopaminergic selectivity and a broad-based pharmacology encompassing serotonin, dopamine, muscarinic, and adrenergic receptor binding affinities. The authors' goal was to compare the incidence of tardive dyskinesia among patients receiving olanzapine and those receiving the conventional dopamine 2 antagonist haloperidol. METHOD: Data were analyzed from three actively controlled and blind long-term responder studies of subjects meeting DSM-III-R criteria for schizophrenia, schizophreniform disorder, or schizoaffective disorder treated with olanzapine (N = 707, up to 20 mg/day, 237 median days of exposure) or haloperidol (N = 197, up to 20 mg/day, 203 median days of exposure) who did not have evidence of tardive dyskinesia at baseline. All of the subjects had a chronic disease course (mean greater than 10 years), and there were no significant between-treatment group differences in demographic or disease characteristics. The Abnormal Involuntary Movement Scale and research diagnostic criteria for tardive dyskinesia were used to define the comparative incidence rates of long-term treatment-emergent tardive dyskinesia. RESULTS: The incidence of newly emergent tardive dyskinesia at any visit after baseline, at the final visit, and at the final two clinical assessments was statistically significantly lower among olanzapine-treated patients than among haloperidol-treated patients. CONCLUSIONS: These findings support an atypical extrapyramidal symptom profile and the potential of a significantly lower risk of tardive dyskinesia with olanzapine than with haloperidol among patients requiring maintenance antipsychotic treatment.


Subject(s)
Antipsychotic Agents/adverse effects , Dyskinesia, Drug-Induced/epidemiology , Haloperidol/adverse effects , Pirenzepine/analogs & derivatives , Adult , Antipsychotic Agents/therapeutic use , Benzodiazepines , Dose-Response Relationship, Drug , Drug Administration Schedule , Dyskinesia, Drug-Induced/etiology , Female , Haloperidol/therapeutic use , Humans , Incidence , Male , Olanzapine , Pirenzepine/adverse effects , Pirenzepine/therapeutic use , Placebos , Psychotic Disorders/drug therapy , Schizophrenia/drug therapy , Severity of Illness Index , Treatment Outcome
9.
Am J Psychiatry ; 154(4): 457-65, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9090331

ABSTRACT

OBJECTIVE: This international, multicenter double-blind trial was designed to compare the therapeutic profile of an atypical antipsychotic, olanzapine, with that of a conventional dopamine D2 antagonist, haloperidol. METHOD: A total of 1,996 patients at 174 sites in Europe and North America were randomly assigned to treatment with olanzapine (N = 1,336) or haloperidol (N = 660) over 6 weeks. The primary efficacy analysis involved the mean change from baseline to endpoint in total scores on the Brief Psychiatric Rating Scale (BPRS). Secondary analyses included comparisons of the mean change in positive and negative symptoms, comorbid depression, extrapyramidal symptoms, and overall drug safety. RESULTS: Olanzapine demonstrated clinical results superior to those of haloperidol on overall improvement according to the BPRS and on every secondary measure, including depression. Olanzapine was also associated with significantly fewer discontinuations of treatment due to lack of drug efficacy or adverse events. Substantially more olanzapine-treated patients (66.5%) than haloperidol-treated patients (46.8%) completed 6 weeks of therapy. Statistically significant advantages of olanzapine treatment were related to 1) change in negative symptoms, 2) extrapyramidal symptom profile, 3) effect on prolactin levels, and 4) response rate. CONCLUSIONS: Olanzapine shows a superior and broader spectrum of efficacy in the treatment of schizophrenic psychopathology, with a substantially more favorable safety profile, than haloperidol. It meets several of the criteria for a novel atypical antipsychotic agent.


Subject(s)
Antipsychotic Agents/therapeutic use , Haloperidol/therapeutic use , Pirenzepine/analogs & derivatives , Psychotic Disorders/drug therapy , Schizophrenia/drug therapy , Adolescent , Adult , Antipsychotic Agents/adverse effects , Basal Ganglia Diseases/chemically induced , Basal Ganglia Diseases/epidemiology , Benzodiazepines , Comorbidity , Depressive Disorder/diagnosis , Depressive Disorder/epidemiology , Double-Blind Method , Europe , Female , Haloperidol/adverse effects , Humans , Male , North America , Olanzapine , Patient Dropouts , Pirenzepine/adverse effects , Pirenzepine/therapeutic use , Psychiatric Status Rating Scales/statistics & numerical data , Psychotic Disorders/epidemiology , Psychotic Disorders/psychology , Schizophrenia/epidemiology , Schizophrenic Psychology , Treatment Outcome
10.
J Periodontal Res ; 32(3): 287-94, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9138194

ABSTRACT

The formation of a biological seal around the transmucosal portion of dental implants may be crucial for the long-term success of these therapies. Data to date suggest that the gingival epithelium attaches to dental implants through the formation of hemidesmosomes. Biochemical and genetic data indicate that the laminin isoform, laminin-5, a component of basement membranes, plays a crucial role in the assembly and maintenance of hemidesmosomes. We report the use of soluble laminin-5 as a biological coating of titanium-alloy to promote cell attachment of the gingival epithelial cell line, IHGK. Monoclonal antibodies reactive with laminin-5 depleted the coating solution of all cell attachment activity and blocked cell attachment to laminin-5-coated disks. Immunodepletion with antibodies to fibronectin had no effect. Finally, we demonstrate that IHGK cells assembled hemidesmosomes within 24 h of attachment to laminin-5-coated titanium alloy but not to the titanium alloy alone. These results suggest that soluble laminin-5 may have clinical applications as a dental implant coating to promote the formation of a biological seal.


Subject(s)
Cell Adhesion Molecules/pharmacology , Cell Adhesion/drug effects , Epithelial Attachment/drug effects , Alloys , Amino Acid Sequence , Animals , Antigens, CD/chemistry , Cell Adhesion Molecules/physiology , Cells, Cultured , Dental Alloys/chemistry , Desmosomes/physiology , Epithelial Attachment/cytology , Epithelial Attachment/physiology , Humans , Integrin beta4 , Microscopy, Electron , Molecular Sequence Data , Periodontal Diseases/microbiology , Rats , Surface Properties , Titanium/chemistry , Kalinin
11.
J Biopharm Stat ; 6(2): 127-37, 1996 May.
Article in English | MEDLINE | ID: mdl-8732909

ABSTRACT

The proportional odds model is illustrated in the analysis of two efficacy scales used in a phase II clinical trial involving 81 schizophrenic patients. The proportional odds model preserves the discrete, ordinal nature of one of the scales. The analysis of this data suggested that the relationship between the two scales is not captured by a linear proportional odds model. A linear model and a piecewise linear model for the explanatory variable were therefore compared using likelihood-based analyses. Residuals from both models were compared. Predicted probabilities for the ordinal categories were constructed from the estimated model. Extensions and limitations of the model for interpretation of other trials and for the planning of future trials are discussed.


Subject(s)
Clinical Trials, Phase II as Topic/methods , Proportional Hazards Models , Psychiatry/methods , Antipsychotic Agents/therapeutic use , Benzodiazepines , Humans , Linear Models , Multicenter Studies as Topic , Olanzapine , Pirenzepine/analogs & derivatives , Pirenzepine/therapeutic use , Schizophrenia/drug therapy
12.
J Invest Dermatol ; 105(4): 557-61, 1995 Oct.
Article in English | MEDLINE | ID: mdl-7561158

ABSTRACT

HaCaT cells, an immortalized keratinocyte line, incubated in plastic wells in the presence of conditioned medium from 804G cells adhered and spread rapidly in less than 30 min. In contrast, cells plated in fibroblast or keratinocyte conditioned medium adhered poorly and remained rounded at 30 min. Immunodepletion of 804G conditioned medium with polyclonal antisera to laminin-5r, but not control antisera, abolished rapid cell spreading. Electron microscopy of HaCaT cells spread by incubation in 804G conditioned medium, but not control medium, revealed mature hemidesmosomes after 24 h. Rapid spreading was also observed in wells precoated with 804G conditioned medium or 804G cell-deposited matrix, but not with fibronectin, vitronectin, or laminin-1. Immunoblotting of 804G conditioned medium with anti-laminin-5r antibodies unveiled polypeptides of 150, 140, 135, and 100 kDa, identical by electrophoretic mobility to immunoreactive polypeptides in 804G deposited matrix. Our results suggest that addition of laminin-5r in a soluble form is sufficient to promote rapid spreading and hemidesmosome assembly in keratinocytes. The mechanism of soluble laminin-5r action may include efficient surface "priming" for cell adhesion. Soluble laminin-5r may have a physiologic role in morphogenesis and repair of the epidermis and may be of use for therapeutic applications.


Subject(s)
Intercellular Junctions/metabolism , Keratinocytes/drug effects , Laminin/pharmacology , Neoplasm Proteins/pharmacology , Animals , Carcinoma/pathology , Cell Adhesion/physiology , Cell Line, Transformed , Cell Size , Culture Media, Conditioned/pharmacology , Extracellular Matrix Proteins/pharmacology , Humans , Immune Sera/pharmacology , Keratinocytes/metabolism , Keratinocytes/ultrastructure , Rats , Solubility , Tumor Cells, Cultured , Urinary Bladder Neoplasms/pathology , Wound Healing
13.
J Cell Sci ; 107 ( Pt 12): 3339-49, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7706390

ABSTRACT

In epithelial cells integrins are segregated on discrete domains of the plasma membrane. Redistribution may also occur during migration or differentiation. However, little is known about the mechanisms that control such redistribution. Receptor internalization may be a part of one such mechanism. We developed a quantitative assay and measured internalization of two epithelial integrin heterodimers, alpha 6 beta 1 and alpha 6 beta 4, induced by cross-linking with specific antibodies. alpha 6 beta 1 is a receptor for EHS laminin, while alpha 6 beta 4 is a receptor for a component of the basement membrane. alpha 6 beta 4 plays an important role in the establishment of hemidesmosomes, and becomes redistributed on the epithelial cell surface when cells are in a migratory phase. We report that alpha 6 beta 4 is efficiently internalized in human keratinocytes. More than 25% of cell surface alpha 6 beta 4 was internalized at 30 minutes, after cross-linking with A9, an anti-beta 4 monoclonal antibody. alpha 6 beta 1 is also internalized, in melanoma and teratocarcinoma cells, with maximum values of 20% of total receptors expressed at the cell surface. No significant difference was observed between the alpha 6 isoforms A and B in these assays. To determine whether alpha 6 cytoplasmic domains could influence integrin endocytosis, we prepared chimeric constructs with the extracellular domain of a reporter protein (CD8), and the cytoplasmic domains of either alpha 6 A or alpha 6 B. Both alpha 6 cytoplasmic domains but not a control cytoplasmic domain promoted internalization of the chimeric proteins, after cross-linking with antibody. Internalization of alpha 6 integrins may have a role in redistributing these receptors at the cell surface. Furthermore, the cytoplasmic domains of alpha 6 may be involved in regulating integrin internalization.


Subject(s)
Antigens, Surface/metabolism , Endocytosis/physiology , Integrins/metabolism , Receptors, Laminin/metabolism , Animals , Biological Transport , CD8 Antigens/biosynthesis , CD8 Antigens/genetics , Cell Adhesion/physiology , Cross-Linking Reagents , Fluorescent Antibody Technique , Humans , Integrin alpha6 , Integrin alpha6beta1 , Integrin alpha6beta4 , Integrins/genetics , Keratinocytes/physiology , Melanoma/metabolism , Mice , Precipitin Tests , Recombinant Fusion Proteins/biosynthesis , Structure-Activity Relationship , Teratocarcinoma/metabolism , Tumor Cells, Cultured
15.
Biometrics ; 49(1): 249-58, 1993 Mar.
Article in English | MEDLINE | ID: mdl-8513107

ABSTRACT

The use of valid constrained randomization is presented for a therapeutic efficacy trial. The construction and evaluation of randomization schemes are studied for two treatment replicates per block and for hypothesized linear gradients. Two different isomorphism classes of designs are compared using the variance of the mean squared error criterion. The results indicate that valid constrained randomization schemes can be constructed that are superior to ordinary randomization. A mastitis efficacy trial provided the specific problem to be solved.


Subject(s)
Randomized Controlled Trials as Topic/methods , Animals , Biometry , Cattle , Female , Mastitis, Bovine/drug therapy , Models, Statistical , Randomized Controlled Trials as Topic/statistics & numerical data , Randomized Controlled Trials as Topic/veterinary
16.
Neurotoxicol Teratol ; 14(3): 205-10, 1992.
Article in English | MEDLINE | ID: mdl-1635541

ABSTRACT

In many toxicology studies, it is common to take the same measurements on an individual animal at several time points (e.g., body weight across days or weeks, activity levels either within a single test session or across days). Such repeated measures for both maternal and offspring endpoints routinely are incorporated into developmental toxicology studies to allow characterization of the profile of treatment-related effects over time. To permit a valid statistical analysis, repeated measures studies are characterized by: random assignment of treatment to experimental units, measurement of the variable(s) of interest at the same time points for all animals, and avoidance of systematic overlaying of treatment and potential response gradients. Assumptions for and advantages of the use of a repeated measures analysis of variance versus single-factor analyses at each time point are illustrated in two data sets from a rat perinatal and postnatal study. The variance-covariance structure of repeated measures designs dictates that adjustments are necessary to provide protection against inflated Type 1 error rates. Communication between statisticians and toxicologists which allow the implementation of such analyses can improve the interpretation of data resulting from repeated measures study designs.


Subject(s)
Data Interpretation, Statistical , Nervous System/drug effects , Analysis of Variance , Animals , Nervous System/embryology , Nervous System/growth & development
17.
J Cell Biol ; 115(3): 843-50, 1991 Nov.
Article in English | MEDLINE | ID: mdl-1833411

ABSTRACT

Laminin is the first extracellular matrix protein expressed in the developing mouse embryo. It is known to influence morphogenesis and affect cell migration and polarization. Several laminin receptors are included in the integrin family of extracellular matrix receptors. Ligand binding by integrin heterodimers results in signal transduction events controlling cell motility. We report that the major laminin receptor on murine embryonic stem (ES) cells is the integrin heterodimer alpha 6 beta 1, an important receptor for laminin in neurons, lymphocytes, macrophages, fibroblasts, platelets and other cell types. However, the cytoplasmic domain of the ES cell alpha 6 (alpha 6 B) differs totally from the reported cytoplasmic domain amino acid sequence of alpha 6 (alpha 6 A). Comparisons of alpha 6 cDNAs from ES cells and other cells suggest that the alpha 6 A and alpha 6 B cytoplasmic domains derive from alternative mRNA splicing. Anti-peptide antibodies to alpha 6 A are unreactive with ES cells, but react with mouse melanoma cells and embryonic fibroblasts. When ES cells are cultured under conditions that permit their differentiation, they become positive for alpha 6 A, concurrent with the morphologic appearance of differentiated cell types. Thus, expression of the alpha 6 B beta 1 laminin receptor may be favored in undifferentiated, totipotent cells, while the expression of alpha 6 A beta 1 receptor occurs in committed lineages. While the functions of integrin alpha chain cytoplasmic domains are not understood, it is possible that they contribute to transferring signals to the cell interior, e.g., by delivering cytoskeleton organizing signals in response to integrin engagement with extracellular matrix ligands. It is therefore reasonable to propose that the cellular responses to laminin may vary, according to what alpha subunit isoform (alpha 6 A or alpha 6 B) is expressed as part of the alpha 6 beta 1 laminin receptor. The switch from alpha 6 B to alpha 6 A, if confirmed in early embryos, could then be of striking potential relevance to the developmental role of laminin.


Subject(s)
Integrins/genetics , Receptors, Antigen/genetics , Receptors, Immunologic/genetics , Stem Cells/physiology , Amino Acid Sequence , Animals , Antibodies , Base Sequence , Cell Adhesion , Cell Line , Embryo, Mammalian , Extracellular Matrix Proteins/analysis , Integrins/analysis , Mice , Molecular Sequence Data , Molecular Weight , Peptides/chemical synthesis , Peptides/immunology , Polymerase Chain Reaction/methods , Receptors, Immunologic/analysis , Receptors, Laminin , Sequence Homology, Nucleic Acid , Stem Cells/cytology
18.
Proc Natl Acad Sci U S A ; 88(22): 10183-7, 1991 Nov 15.
Article in English | MEDLINE | ID: mdl-1946438

ABSTRACT

The integrin heterodimers composed of the alpha 6 subunit with the beta 1 or beta 4 subunit (alpha 6 beta 1 and alpha 6 beta 4) are receptors for laminin and basement membrane components, respectively. The alpha 3 beta 1 integrin recognizes laminin, collagen, fibronectin, or epiligrin. We report the identification of structural variants (A and B) of the alpha 6 and alpha 3 subunits, containing distinct cytoplasmic domains. The expression of one cytoplasmic domain or the other, based probably on alternative exon usage, is cell-type dependent. Most transformed cell lines express both alpha 6A and alpha 6B isoforms, as determined by mRNA amplification or antibody immunoprecipitation. In contrast, embryonic fibroblasts express exclusively alpha 6A, and embryonic stem cells express exclusively alpha 6B. In most normal tissues, both alpha 6 isoforms are detectable, but several tissues express either alpha 6A or alpha 6B. The alpha 3B mRNA was amplified from heart and brain, while all other tissues and cell lines tested contained only alpha 3A mRNA. Alternative cytoplasmic domains may provide a means for varying the cellular responses to the ligands of alpha 6 and alpha 3 integrins according to the cell type.


Subject(s)
Genetic Variation , Integrins/genetics , Amino Acid Sequence , Animals , Base Sequence , Cell Line , Cloning, Molecular , Cricetinae , Cytoplasm/physiology , Gene Expression , Humans , Immunoblotting , Macromolecular Substances , Molecular Sequence Data , Oligodeoxyribonucleotides , Polymerase Chain Reaction/methods , RNA, Messenger/genetics , Sequence Homology, Nucleic Acid
19.
Fundam Appl Toxicol ; 17(3): 482-93, 1991 Oct.
Article in English | MEDLINE | ID: mdl-1794652

ABSTRACT

The toxicity and leukopenia produced by vinblastine or desacetyl vinblastine were established in 1-month studies in rats. Groups of male Fischer 344 rats were given weekly intravenous doses of vinblastine or desacetyl vinblastine at doses of 0.08, 0.16, 0.32, 0.64, or 1.28 mg/kg. The target organ toxicity was similar for both compounds. Decreased cell production in the thymus, testes, and bone marrow was produced in the animals of the two highest dose groups for both compounds with the degree of severity greater in the highest dose group. All high dose rats (1.28 mg/kg) given desacetyl vinblastine and three rats given vinblastine died prior to study termination. Body weight loss was more pronounced in high dose rats given desacetyl vinblastine, but at lower doses there were no significant differences in body weight reduction for rats receiving either compound. Leukopenia occurred at all dose levels of 0.32 mg/kg and higher. During the first 2 weeks of the study, rats given 1.28 mg/kg of desacetyl vinblastine had a greater leukopenic response than rats given 1.28 mg/kg of vinblastine. It is concluded that both compounds produced similar target organ toxicity and leukopenia without deaths at doses of 0.32 and 0.64 mg/kg given once a week for 4 weeks. At the high dose (1.28 mg/kg) desacetyl vinblastine was more toxic than vinblastine resulting in greater mortality and body weight reduction.


Subject(s)
Leukopenia/chemically induced , Vinblastine/toxicity , Animals , Body Weight/drug effects , Bone Marrow/drug effects , Bone Marrow/pathology , Injections, Intravenous , Leukocyte Count/drug effects , Male , Rats , Rats, Inbred F344 , Testis/drug effects , Thymus Gland/drug effects
20.
J Cell Biol ; 113(2): 405-16, 1991 Apr.
Article in English | MEDLINE | ID: mdl-1826298

ABSTRACT

The integrin alpha 6 beta 1 is a prominent laminin receptor used by many cell types. In the present work, we isolate clones and determine the primary sequence of the chick integrin alpha 6 subunit. We show that alpha 6 beta 1 is a prominent integrin expressed by cells in the developing chick retina. Between embryonic days 6 and 12, both retinal ganglion cells and other retinal neurons lose selected integrin functions, including the ability to attach and extend neurites on laminin. In retinal ganglion cells, we show that this is correlated with a dramatic decrease in alpha 6 mRNA and protein, suggesting that changes in gene expression account for the developmental regulation of the interactions of these neurons with laminin. In other retinal neurons the expression of alpha 6 mRNA and protein remains high while function is lost, suggesting that the function of the alpha 6 beta 1 heterodimer in these cells is regulated by posttranslational mechanisms.


Subject(s)
Gene Expression Regulation , Integrins/genetics , Receptors, Immunologic/genetics , Retina/growth & development , Amino Acid Sequence , Animals , Base Sequence , Chick Embryo , Cloning, Molecular , DNA , Humans , Integrins/metabolism , Molecular Sequence Data , Precipitin Tests , Protein Biosynthesis , Receptors, Immunologic/metabolism , Receptors, Laminin , Restriction Mapping , Retina/metabolism , Retinal Ganglion Cells/metabolism , Sequence Homology, Nucleic Acid , Transcription, Genetic
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