Biomedical subjects

R Kramer

Publications and source records attributed to R Kramer.

At least 19 recordsLinked to original sources

PubMed2000

A pilot trial assessing the efficacy of paroxetine hydrochloride (Paxil) in controlling hot flashes in breast cancer survivors.

BACKGROUND: Many breast cancer survivors suffer debilitating hot flashes. Estrogen, the drug of choice in perimenopausal women, is generally not recommenced to breast cancer survivors. Nonhormonal treatments are mostly disappointing. Anecdotal reports in our institution suggested that the selective serotonin-reuptake inhibitor, paroxetine hydrochloride, might be efficacious in alleviating hot flashes. PATIENTS AND METHODS: Thirty women with prior breast cancer who were suffering at least two hot flashes a day entered a single institution pilot trial to evaluate paroxetine's efficacy in reducing the frequency and severity of hot flashes. After completing daily diaries for one week on no therapy, the women received open-label paroxetine, 10 mg daily for one week, followed by four weeks of paroxetine, 20 mg daily. The women completed hot-flash daily diaries throughout the study period, and a health-related symptom-assessment questionnaire and a quality-of-life rating scale in the first and sixth week of the study. RESULTS: Twenty-seven women completed the six-week study period. The mean reduction of hot flash frequency was 67% (95% confidence interval (95% CI): 56%-79%). The mean reduction in hot flash severity score was 75% (95% CI: 66%-85%). There was a statistically significant improvement in depression, sleep, anxiety, and quality of life scores. Furthermore, 25 (83%) of the study participants chose to continue paroxetine therapy at the end of study. The most common adverse effect was somnolence, resulting in drug discontinuation in two women, and dose reduction in two women. One woman discontinued drug due to anxiety. CONCLUSIONS: Paroxetine hydrochloride is a promising new treatment for hot flashes in breast cancer survivors, and warrants further evaluation in a double-blind randomized placebo-controlled trial.

Adult↗

PubMed1999

Cytosolic phospholipase A2 is induced in reactive glia following different forms of neurodegeneration.

Many recent studies have emphasized the deleterious role of inflammation in CNS injury. Increases in free fatty acids, eicosanoids, and products of lipid peroxidation are known to occur in various conditions of acute and chronic CNS injury, including cerebral ischemia, traumatic brain injury, and Alzheimer's disease. Although an inflammatory response can be induced by many different means, phospholipases, such as cytosolic phospholipase A(2) (cPLA(2)), may play an important role in the production of inflammatory mediators and in the production of other potential second messengers. cPLA(2) hydrolyzes membrane phospholipids and its activity liberates free fatty acids leading directly to the production of eicosanoids. We investigated the cellular localization of cytosolic phospholipase A(2) in the CNS following: (1) focal and global cerebral ischemia, (2) facial nerve axotomy, (3) human cases of Alzheimer's disease, (4) transgenic mice overexpressing mutant superoxide dismutase, a mouse model of amyotrophic lateral sclerosis, and (5) transgenic mice overexpressing mutant amyloid precursor protein, which exhibits age-related amyloid deposition characteristic of Alzheimer's disease. We show that in every condition evaluated, cytosolic phospholipase A(2) is present in reactive glial cells within the precise region of neuron loss. In conditions where neurons did not degenerate or are protected from death, cytosolic phospholipase A(2) is not observed. Both astrocytes and microglial cells are immunoreactive for cytosolic phospholipase A(2) following injury, with astrocytes being the most consistent cell type expressing cytosolic phospholipase A(2). The presence of cytosolic phospholipase A(2) does not merely overlap with reactive astroglia, as reactive astrocytes were observed that did not exhibit cytosolic phospholipase A(2) immunoreactivity. In most conditions evaluated, inflammatory processes have been postulated to play a pivotal role and may even participate in neuronal cell death. These results suggest that cytosolic phospholipase A(2) may prove an attractive therapeutic target for neurodegeneration.

Alzheimer Disease↗

PubMed1999

Detection of intracellular tumor necrosis factor alpha in stimulated fetal cells.

BACKGROUND: It is unknown if immature fetal cells produce tumor necrosis factor (TNF) alpha in the same manner that adult cells do. The aim of this study was to determine the feasibility of early detection of intracellular TNF produced by circulating human monocytes (Mo) and lymphocytes (Ly) using flow cytometry and to compare the stimulation profiles of mature and fetal cells. MATERIAL AND METHODS: Fetal umbilical cord blood (n = 10) and adult volunteer blood (n = 10) were obtained. In vitro stimulation with endotoxin (LPS) and ionomycin-PMA was performed. Brefeldin A was added to prevent extracellular transport of TNF. Cell type was determined by using CD-14 marker separating monocyte and lymphocyte populations. Anti-human TNF monoclonal antibody was used to detect intracellular TNF by flow cytometry analysis. RESULTS: Thirty to sixty thousand cells were analyzed per sample. Average TNF expression of stimulated fetal Mo was 28.2%, and that of fetal Ly was only 1.1%. Adult stimulated Ly had an average TNF expression of 31.9%, and adult Mo, 29.6% (P < 0.05 for adult Ly vs fetal Ly). CONCLUSION: TNF flow cytometry analysis allows assessment of individual cell types and their ability to produce that cytokine. Fetal cells are able to produce TNF when stimulated, but the stimulation profile of Ly differs from that of adult samples. This observation may be of clinical importance in evaluating the response of immature cells to a septic stimulus. Flow cytometry is reliable, reproducible, quick, and easily obtained from a small sample of peripheral blood. Clinical use will be applicable once appropriate controls are developed, as reported in this study.

Adult↗

PubMed1999

Phospholipase A2 enzymes regulate alpha IIb beta3-mediated, but not Fc gammaRII receptor-mediated, pp125FAK phosphorylation in platelets.

The alphaII(b)beta3 integrin and FcgammaRII receptors mediate, respectively, platelet adhesion and spreading on fibrinogen and immunoglobulin (IgG) coated surfaces. Platelet adhesion to fibrinogen resulted in a partial conversion of the faster to the slower migrating (phosphorylated) form of Ca(+2)-sensitive cytosolic phospholipase A2(cPLA2) but failed to trigger arachidonic acid (AA) release. Full mobility shift of cPLA2 and a massive release of AA release were stimulated by platelet adhesion to IgG or addition of thrombin to the fibrinogen adherent platelets. IgG and thrombin induced AA production were blocked by methyl arachidonyl fluorophosphonate (MAFP), an irreversible inhibitor of cPLA2 and the Ca(+2)-independent phospholipase A2 (iPLA2). In contrast, bromoenol lactone (BEL), a specific inhibitor of iPLA2 had no effect on the release of AA. MAFP and BEL prevented pp125FAK phosphorylation and platelet spreading on fibrinogen having no effect on pp125FAK phosphorylation or platelet spreading on immobilized IgG. We conclude that alpha(IIb)beta3-mediated pp125FAK phosphorylation and platelet spreading on fibrinogen are regulated by PLA2 enzymes.

Arachidonic Acid↗

PubMed1998

Novel C5a receptor antagonists regulate neutrophil functions in vitro and in vivo.

Novel recombinant human C5a receptor antagonists were discovered through modification of the C terminus of C5a. The C5a1-71T1M,C27S,Q71C monomer, (C5aRAM; CGS 27913), was a pure and potent functional antagonist. The importance of a C-terminal cysteine at position 71 to antagonist properties of C5aRAM was confirmed by studying C5a1-71 derivatives with replacements of Q71, C5a derivatives of various lengths (70-74) with C-terminal cysteines, and C5a derivatives of various lengths (71-74) with Q71C replacements. The majority of C5a1-71Q71 derivatives were agonists (C5a-like) in the human neutrophil C5a-induced intracellular calcium mobilization assay. The C5a1-71Q71C derivative was an antagonist. C5a derivatives of lengths 73 and 74 with C-terminal cysteines were agonists, while lengths 70 to 72 were antagonists. C5a derivatives of lengths 72, 73, and 74 with Q71C replacements were agonists, while, again, C5a1-71Q71C was an antagonist. C5aRAM and its adducts, including its dimer, C5aRAD (CGS 32359), were pure antagonists. Additionally, CSaRAM and CSaRAD inhibited binding of 125I-labeled recombinant human C5a to neutrophil membranes (Ki = 79 and 2 pM, respectively), C5a-stimulated neutrophil intracellular calcium mobilization (8 and 13 nM), CD11b integrin up-regulation (10 and 1 nM), superoxide generation (182 and 282 nM), lysozyme release (1 and 2 microM), and chemotaxis (11 and 7 microM). In vivo, intradermal injection of C5aRAM inhibited C5a-induced dermal edema in rabbits. Furthermore, a 5-mg/kg i.v. bolus of C5aRAD significantly inhibited C5a-induced neutropenia in micropigs when challenged with C5a 30 min after C5aRAD administration. C5aRAM and C5aRAD are novel, potent C5a receptor antagonists devoid of agonist or proinflammatory activity with demonstrated efficacy in vitro and in vivo.

Animals↗

PubMed1998

Psychopathology associated with suicidal ideation and attempts among children and adolescents.

OBJECTIVE: To identify the independent and differential diagnostic and symptom correlates of suicidal ideation and suicide attempts and determine whether there are gender- and age-specific diagnostic profiles. METHOD: The relationships between suicidal ideation, suicide attempts, and psychiatric disorders were examined among 1,285 randomly selected children and adolescents, aged 9 to 17 years, of whom 42 had attempted suicide and 67 had expressed suicidal ideation only. Youths and their parents were interviewed as part of the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study, using the Diagnostic Interview Schedule for Children Version 2.3 (DISC-2.3). RESULTS: Logistic regression analyses indicated that mood, anxiety, and substance abuse/dependence disorders independently increased the risk of suicide attempts, after controlling for sociodemographic characteristics. There was no significant independent contribution of disruptive disorders to suicide attempts, although its association with suicidal ideation was significant. Substance abuse/dependence independently differentiated suicide attempters from ideators. Noncriterion symptoms that remained significant predictors of suicide risk, after adjusting for psychiatric disorder, included panic attacks and aggressiveness. Perfectionism did not significantly increase suicide risk after adjusting for psychiatric disorder. The association of specific disorders and noncriterion symptoms with suicidality varied as a function of gender and age. CONCLUSION: A monolithic diagnostic risk profile for suicidality, ignoring gender- and age-specific risks, is inadequate. The contribution of substance abuse/dependence in the escalation from suicidal thoughts to suicide attempts is underscored.

Adolescent↗

PubMed1997

Maintenance of acetylcholine receptor number by neuregulins at the neuromuscular junction in vivo.

ARIA (for acetylcholine receptor-inducing activity), a protein purified on the basis of its ability to stimulate acetylcholine receptor (AChR) synthesis in cultured myotubes, is a member of the neuregulin family and is present at motor endplates. This suggests an important role for neuregulins in mediating the nerve-dependent accumulation of AChRs in the postsynaptic membrane. Nerve-muscle synapses have now been analyzed in neuregulin-deficient animals. Mice that are heterozygous for the deletion of neuregulin isoforms containing an immunoglobulin-like domain are myasthenic. Postsynaptic AChR density is significantly reduced, as judged by the decrease in the mean amplitude of spontaneous miniature endplate potentials and bungarotoxin binding. On the other hand, the mean amplitude of evoked endplate potentials was not decreased, due to an increase in the number of quanta released per impulse, a compensation that has been observed in other myasthenic states. Thus, the density of AChRs in the postsynaptic membrane depends on immunoglobulin-containing neuregulin isoforms throughout the life of the animal.

Acetylcholine↗

PubMed1997

Neuritin: a gene induced by neural activity and neurotrophins that promotes neuritogenesis.

Neural activity and neurotrophins induce synaptic remodeling in part by altering gene expression. A cDNA encoding a glycosylphoshatidylinositol-anchored protein was identified by screening for hippocampal genes that are induced by neural activity. This molecule, named neuritin, is expressed in postmitotic-differentiating neurons of the developing nervous system and neuronal structures associated with plasticity in the adult. Neuritin message is induced by neuronal activity and by the activity-regulated neurotrophins BDNF and NT-3. Purified recombinant neuritin promotes neurite outgrowth and arborization in primary embryonic hippocampal and cortical cultures. These data implicate neuritin as a downstream effector of activity-induced neurite outgrowth.

Amino Acid Sequence↗

PubMed1997

Identification of the human alpha6 integrin gene promoter.

The alpha6 integrin subunit couples with either the beta1 or the beta4 subunit to form a laminin receptor. alpha6 expression is cell-type-specific and generally is present at high levels in epithelial and endothelial cells. To study its gene regulation, we isolated a genomic clone containing the human alpha6 integrin gene promoter. It includes 3 kb of the upstream flanking region, the first exon (385 bp), and 9 kb of the first intron. The alpha6 promoter directs transcription initiation from a primary site 202 nucleotides from the translation initiation codon. Unlike most other integrin gene promoters, the alpha6 promoter has a TATA box (GATAAA), which is located 22 nucleotides upstream from the primary transcription initiation site. A 190-bp region upstream from the TATA box is highly rich (78%) in C and G nucleotides and contains several Sp1 and AP2 binding sequences. However, full promoter activity (in the presence of the SV40 enhancer) requires only 78 bp of this C/G-rich sequence upstream from the TATA box. Slightly upstream from the C/G-rich region are a steroid receptor binding homolog and an epithelial-cell-specific E-pal sequence. Another possible epithelial cell-specific binding sequence (Ker1) is found immediately downstream from the TATA box. Cell-type-specific activities of the promoter paralleled the alpha6 mRNA levels in four tested cell lines. In the presence of the SV40 enhancer, alpha6 promoter activity increased approximately four-fold in primary keratinocytes and in HT1080 fibrosarcoma cells and 30-fold in T47D breast carcinoma cells, but remained undetectable in K562 leukemia cells. Genomic analysis that compared alpha6-expressing with non-alpha6-expressing cells suggested that DNA methylation is not involved in the silencing of the alpha6 gene in alpha6-negative cells. DNase I footprint analysis confirmed the binding of Sp1 and AP2 to their cognate sequences. A nuclear extract of high-alpha6-expressing HBL-100 cells also produced significant binding to these sites, suggesting that the two transcription factors are probably involved in the positive regulation of the alpha6 promoter.

Amino Acid Sequence↗

PubMed1997

Intergenerational transmission of parental bonding among women.

OBJECTIVE: To examine the transmission of parental bonding style from mothers to daughters. METHOD: Sixty mothers and their 69 daughters were independently assessed over the course of a 10-year follow-up. The Parental Bonding instrument was administered to both mothers and daughters to assess their own childhood parenting. Depression was assessed using the Schedule for Affective Disorders and Schizophrenia-Lifetime version. Temperament was assessed through self-report on the Dimensions of Temperament Survey. A series of logistic regressions were run to predict daughter report of maternal affectionless control, taking into account maternal and daughter depression status, temperament, and socioeconomic status. RESULTS: The intergenerational transmission of parental bonding among women was shown to be independent of maternal depression, daughter depression, maternal temperament, daughter temperament, and socioeconomic status. CONCLUSION: Given the previously established association between parental bonding style and depression in offspring, the sturdiness of the intergenerational transmission of parental bonding among women suggests the routine clinical assessment of maternal bonding style.

Adolescent↗

PubMed1997

Attacking the disability and absenteeism epidemic--behavioral health care solutions.

To remain competitive in a global economy, employers must implement effective programs to stem escalating disability claims and increased costly absenteeism. This article discusses methods to counter this latest workforce epidemic. The authors discuss employee attitudes, legal considerations and behavioral health care solutions.

Absenteeism↗

PubMed1997

The EEOC's new ADA mental disability guidelines: an EAP is a pretty reasonable accommodation.

The EEOC's enforcement guidelines for psychiatric disabilities may present a significant challenge for the small employer. The authors discuss the parameters of this challenge and consider the ADA mental disability guidelines in the context of an operational framework to assist employers. It is pointed out that an EAP or a managed behavioral health firm with knowledge of ADA can be useful in identifying cost-effective accommodations for employees claiming mental disabilities.

Absenteeism↗

PubMed1997

Bioequivalence evaluation of two flutamide preparations in healthy female subjects.

In the present study two different preparations containing 250 mg flutamide (3'-trifluoromethyl-4'-nitro-2-methyl-propionylanilide, CAS 13311-84-7) were compared in 20 female subjects. The trial was performed in a randomized two-way cross-over design. Each subject received one tablet with 250 mg flutamide in each period. The two treatment periods were separated by a wash-out phase of 7 days. Blood samples were obtained just before dosing and 18 times during the subsequent 36 h. The plasma concentrations of flutamide, 2-hydroxyflutamide and trifluoromethylnitroaniline were determined by HPLC with UV-detection. Due to the low plasma levels of the parent drug flutamide, the data of the pharmacologically active metabolite 2-hydroxyflutamide (CAS 52806-53-8) were used for bioequivalence assessment. The following mean values were obtained after administration of the test and reference preparation respectively: Flutamide: AUC0-36 = 95.82 ng.h/ml vs 93.33 ng.h/ml, Cmax = 44.78 ng/ml vs 38.73 ng/ml, tmax = 1.71 h vs 1.66 h, 2-hydroxyflutamide: AUC0-infinity = 6090.73 ng.h/ml vs 6068.83 ng. h/ml, Cmax = 772.74 ng/ml vs 779.84 ng/ml, tmax = 2.21 h vs 2.17 h, t1/2 = 8.21 h vs 8.32 h, trifluoromethylnitroaniline: AUC0-infinity = 1771.87 ng.h/ml vs 1701.44 ng.h/ml, Cmax = 173.36 ng/ml vs 171.32 ng/ml, tmax = 2.74 h vs 2.63 h, t1/2 = 10.75 h vs 9.83 h. The two preparations proved to be bioequivalent.

Adult↗

PubMed1996

Mechanism of topoisomerase II inhibition by staurosporine and other protein kinase inhibitors.

Topoisomerase II is an essential enzyme for proliferation of eukaryotic cells. It is also a target for many antineoplastic drugs that promote stabilization of covalent complexes between topoisomerase II and DNA. Topoisomerase II and protein kinases both catalyze the transfer of phosphoester bonds from nucleotides to proteins. This similarity suggests that inhibitors may affect both classes of enzymes. In the present study, we have examined the mechanism of topoisomerase II inhibition by three different classes of protein kinase inhibitors. We report that staurosporine inhibited the catalytic activity of topoisomerase II by blocking the transfer of phosphodiester bonds from DNA to the active tyrosine site, a mechanism of inhibition not previously reported for this enzyme. In contrast, other kinase inhibitors, such as methyl 2,5-dihydroxycinnamate, most likely inactivated topoisomerase II by alkylation of essential amino acids, whereas the mechanism of inhibition of bis-indolylmaleimide possibly involved a direct interaction with DNA.

Adenosine Triphosphate↗

PubMed1996

Neuregulins with an Ig-like domain are essential for mouse myocardial and neuronal development.

Neuregulins are ligands for the erbB family of receptor tyrosine kinases and mediate growth and differentiation of neural crest, muscle, breast cancer, and Schwann cells. Neuregulins contain an epidermal growth factor-like domain located C-terminally to either an Ig-like domain or a cysteine-rich domain specific to the sensory and motor neuron-derived isoform. Here it is shown that elimination of the Ig-like domain-containing neuregulins by homologous recombination results in embryonic lethality associated with a deficiency of ventricular myocardial trabeculation and impairment of cranial ganglion development. The erbB receptors are expressed in myocardial cells and presumably mediate the neuregulin signal originating from endocardial cells. The trigeminal ganglion is reduced in size and lacks projections toward the brain stem and mandible. We conclude that IgL-domain-containing neuregulins play a major role in cardiac and neuronal development.

Animals↗

PubMed1996

Keratinocytes in human wounds express alpha v beta 6 integrin.

Cell adhesion receptors of the integrin family play a major role during re-epithelialization of human wounds. We have previously documented that the expression of alpha v family integrins is induced in keratinocytes of mucosal wounds [1]. In the present investigation, we extended these studies to determine whether alpha v beta 6 integrin is expressed during wound healing in humans. Mucosal and epidermal wound sections from 1- to 7-day-old wounds were used for immunolocalization of integrins and their putative ligands. In addition, freshly isolated epidermal keratinocytes were used to study integrin expression in vitro. Expression of alpha v beta 6 integrin appeared relatively late during mucosal and dermal wound healing. Maximal expression was seen in 7-day-old wounds in which epithelial sheets had fused and granulation tissue was present. Fibronectin and tenascin, both possible ligands for alpha v beta 6 integrin, were found concentrated underneath the basal epithelial cells expressing this receptor, and the maximal expression of tenascin coincided with that of alpha v beta 6 integrin. Freshly isolated epidermal keratinocytes did not stain for alpha v beta 6 integrin but began to express this integrin after subculturing. Our results suggest that the expression of alpha v beta 6 integrin, a putative binding integrin for fibronectin and tenascin, is induced in keratinocytes when epithelial sheets fuse during wound healing.

Antigens, Neoplasm↗

PubMed1996

alpha-(3,4-dimethyoxyphenyl)-3,4-dihydro-6,7-dimethoxy-alpha- [(4-methylphenyl)thio]-2(1H)-isoquinolineheptanenitrile (CL 329,753): a novel chemosensitizing agent for P-glycoprotein-mediated resistance with improved biological properties compared with verapamil and cyclosporine A.

Agents that inhibit P-glycoprotein may restore sensitivity to some antitumor drugs in cancer patients. Optimization of the specificity and potency of one class of chemosensitizing agents related to verapamil has led to the identification of alpha-(3,4-dimethyoxyphenyl)-3,4-dihydro-6, 7-dimethoxy-alpha-[(4-methylphenyl) thio]-2(1H)-isoquinolineheptanenitrile, designated CL 329,753. In vitro, 0.1 to 2.0 microM CL 329,753 restored sensitivity to drugs in the multidrug resistance (MDR) phenotype in cell lines that overexpress P-glycoprotein. CL 329,753 was greater than 10-fold more potent and efficacious than cyclosporine A or verapamil in vitro, particularly in cells that express high levels of P-glycoprotein. The enhanced activity of CL 329,753 may be related to its inability to be transported by P-glycoprotein, since low drug accumulation of cyclosporine or verapamil but not CL 329,753 was found in P-glycoprotein-containing cells, yet all three agents inhibited vinblastine binding to membranes containing P-glycoprotein and inhibited photoaffinity labeling of P-glycoprotein. In vivo, CL 329,753 resensitized drug-resistant tumors to vinblastine or doxorubicin in an ascitic or solid tumor model, respectively. No alteration in the plasma pharmacokinetic profile of doxorubicin by CL 329,753 has been found. Furthermore, the compound had 70-fold less calcium channel antagonistic activity compared with verapamil.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1995

Inhibition of N-linked glycosylation of P-glycoprotein by tunicamycin results in a reduced multidrug resistance phenotype.

Characterisation of altered glycosylation of P-glycoprotein (P-gp) found associated with the absence of a multidrug resistance (MDR) phenotype in cell lines prompted an investigation to assess the role of post-translational processing in establishing P-gp efflux pump functionally. The clone A cell line used in this study displays a strong MDR phenotype mediated by high constitutive levels of expression of P-gp. Incubation of clone A cells with tunicamycin for different periods resulted in a time-dependent increase in daunorubicin accumulation, reflecting a reduction in P-gp function. Parallel experiments conducted with verapamil resulted in no loss of P-gp functionality in clone A cells. Reduction in surface-associated P-gp following exposure to tunicamycin was established by FACS analysis, Western blot analysis and immunoprecipitation of surface-iodinated P-gp. In addition, immunoprecipitation of P-gp from 32P-orthophosphate-labelled cells demonstrated reduced phosphorylation of P-gp associated with tunicamycin exposure. From these studies we conclude that glycosylation of P-gp is required to establish the cellular MDR phenotype.

ATP Binding Cassette Transporter, Subfamily B, Mem↗