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A Bakker

Publications and source records attributed to A Bakker.

At least 91 records · Page 5Linked to original sources
PubMed1996

The quality of the professional practice of community pharmacists: what can still be improved in Europe?

This article describes a research project concerning the professional practice of community pharmacists in Western Europe. In 1990 interviews were held with key figures and practising pharmacists in the Netherlands, Belgium, Great Britain, Sweden and Portugal. In 1991 a questionnaire was sent which was answered by 929 pharmacists. Concerning the quality of the professional practice it appeared that pharmacists have integrated certain structure aspects such as the use of a computer or a separate patient consultation room to varying degrees. Also concerning process aspects with regard to quality, for example the degree to which attention is given to counter work and prescription controls, there are large differences between pharmacists from the different countries. These differences between pharmacists appeared to depend upon differences in legal rules (such as the compulsory presence of a pharmacist in Belgium, Sweden and Portugal or the compulsory prescription control by a pharmacist before delivery in Great Britain), financial and economic circumstances, internal organizational characteristics of the pharmacy and the individual personal task conceptions of the pharmacist. New developments, for example in areas of patient information and computer use, seem to be followed most in the Netherlands and Sweden. General statements about differences in quality are not easily made because the community pharmacy in other countries also has certain positive aspects, such as being easily accessible (Portugal), personal involvement of the pharmacist (Belgium) and personal control by the pharmacist (Great Britain). Looking at the diversity within Europe the conclusion can be reached that the European pharmacist' does not yet exist.

Education, Pharmacy↗
PubMed1996

Current use of thiazide diuretics and prevention of femur fractures.

A case control study of a defined population from The Netherlands was performed to evaluate the risk of femur fractures associated with the use of thiazide diuretics. Included were 386 patients hospitalized for femur fractures between 1986 and 1990 who were residents and 45 years of age and older. Per case, one age-, sex-, pharmacy-, and general practitioner-matched control was chosen from the general population. Drug use was ascertained from computerized pharmacy records. The adjusted odds ratio of current use of thiazide diuretics was 0.5 (95% confidence interval, 0.3-0.9). The protective effect of thiazide diuretics was greatest for use of 1 year or longer at relatively high doses of thiazides (odds ratio, 0.3; 95% confidence interval, 0.1-0.9). We also found that patients who discontinued thiazide use longer than 2 months were not protected against femur fractures. These results support the hypothesis that use of thiazide diuretics protects against femur fractures.

Aged↗
PubMed1996

Prognostic value of TP53 and K-ras-2 mutational analysis in stage III carcinoma of the colon.

BACKGROUND: Genetic mutations involving oncogenes and tumor-suppressor genes occur in carcinogenesis, and may affect biologic behavior of neoplasms. In this study, we analyzed the prognostic value of mutational analysis in colon carcinoma. PATIENTS AND METHODS: Archival pathology specimens from 70 consecutive patients, resected for stage III colon carcinoma, were analyzed for point mutations by amplification and direct sequencing of exons from the K-ras-2 and the TP53 genes (topographic genotyping). Mutations were compared with adverse histopathologic features (poor differentiation, vascular and lymphatic invasion, mucin production) as prognostic markers. RESULTS: Five-year survival was 75% in patients with nonmutated lesions, significantly lower (21%) with TP53 mutations (P = 0.01), and intermediate with K-ras-2 only (45%) or both K-ras-2 and TP53 mutations (36%). A TP53 mutation carried the highest relative risk of death (2.39; 95% confidence interval, 1.29 to 4.42; P = 0.006). There was an additive effect on the risk of death between TP53 mutations and adverse histopathologic features. CONCLUSIONS: The information derived from mutational analysis is creating new prognostic variables that may play a role in the choice of therapy for colorectal carcinoma.

Aged↗
PubMed1996

Comparative p53 mutational analysis of multiple primary cancers of the upper aerodigestive tract.

BACKGROUND: Tumors arising in the upper aerodigestive tract (UAT) are often associated with predisposing factors that place the patient at risk for development of multiple synchronous or metachronous tumors. The aim of this study was to evaluate p53 as a susceptibility gene in UAT malignancy. METHODS: Seventeen patients with 41 separate primary tumors involving esophagus (n = 15), larynx (n = 14), pharynx (n = 6), lung (n = 2), mouth (n = 2), and tongue (n = 2) were analyzed for the presence and specific genotype of p53 point mutation. Immunohistochemical staining of p53 and topographic genotyping consisting of polymerase chain reaction amplification and direct sequencing of p53 exons to 5 to 8 were performed. RESULTS: Eleven tumors were metachronous (6 months to 11 years), and 11 were synchronous. We found p53 point mutations in 19 (46.3%) of 41 tumors in exons 8 (n = 11), 7 (n = 4), 5 (n = 3), and 6 (n = 1). Tumors possessed either wild-type p53 or a single type of point mutation. Metastases displayed the identical genotype of its primary tumor in all cases. Most importantly, p53 genotype was found to be completely discordant between separate primary tumors for the same patient. CONCLUSIONS: Complete discordance in p53 genotype between separate primary UAT cancers strongly indicates that p53 is not functioning as a susceptibility gene in this setting.

Adult↗
PubMed1996

The role of p53 mutation and protein expression in primary and recurrent adenoid cystic carcinoma.

Adenoid cystic carcinoma (ACC) is a malignant tumor of salivary gland origin having a propensity for spread by direct extension or perineural invasion with frequent recurrences. Previous reports have shown that tumor behavior is not always predicted by histological pattern or stage. Little is known of the role of p53 tumor suppressor gene mutation and altered protein expression with respect to ACC pathobiology and recurrence. The authors analyzed a group of 14 ACC specimens (seven primary; seven recurrent) from 13 patients treated between 1987 to 1993. Formalin-fixed, paraffin-embedded specimens were reviewed and subjected to, immunohistochemistry (p53, DO-7, DAKO, Nutley, NJ; and WAF-I, Ab-1, Oncogene Sciences, Uniondale, NY) on 4-microm-thick histological sections as a prelude to p53 genotyping. In one case, sequential material representing primary and recurrent tumor was analyzed. Each tumor specimen was topographically genotyped for p53 point mutational change. Minute tissue samples were removed from unstained sections, polymerase chain reaction (PCR) amplified for p53 exons 5 to 8, and then underwent direct DNA sequencing. Six of seven primary ACCs were p53 immunostain negative. Four of seven recurrent (57%) ACCs were p53 immunopositive. These tumors showed varying degrees of p53 immunopositivity ranging from diffuse, intense staining of most tumor cells (n = 1) to interspersed, strongly positive cells mixed with predominantly p53 immunonegative cells (n = 4). All tumors were WAF-I immunostain negative. Two of the most immunopositive recurrent tumors each manifested a single type of p53 point mutation detected by p53 DNA genotyping (p53 exon 5:codon 175 and p53 exon 6:codon 199). In the case in which both primary and recurrent tumor was available, only the recurrent tumor contained point mutational damage. Negative immunostaining for p53 in primary ACC suggests that p53 mutation is not important in early events involving development of this tumor. In contrast, the frequent presence of p53-positive cells and the detection of point mutations in recurrent ACC suggests that p53 alterations are involved in later stages of tumor progression, important in the phenomenon of ACC recurrence.

Adult↗
PubMed1996

Primary mediastinal and testicular seminomas: a comparison of K-ras-2 gene sequence and p53 immunoperoxidase analysis of 26 cases.

Primary mediastinal seminomas (MS) are rare tumors. Histologically, they are similar to their counterpart in the gonads. The survival rate has varied from 50% to 85% in different series. However, large series of these tumors primarily in the mediastinum are lacking. At the molecular level, a few reports document K-ras mutations in up to 40% of testicular seminomas (TS), localized predominantly to codon 12. Reports on TS p53 immunohistochemistry (IHC) range from negative to overexpression approaching 90% of cases, and by sequence analysis one small series showed a 23% mutation rate. To date, no analyses have been performed for either K-ras mutations or p53 immunohistochemical expression in primary MS. The authors studied 13 cases each of primary MS and TS from archival formalin-fixed, paraffin-embedded sections in which adequate tumor sampling and clinical history, including serological studies, and histological, histochemical, and IHC staining, were performed to confirm the diagnosis. p53 immunoperoxidase staining using citrate buffer/microwave antigen retrieval was performed. Topographic genotyping was performed on 5-microns-thick tissue sections up to 17 years old, in which the neoplastic cell population was sampled. Additionally, multiple sites within a given cases were sampled to determine clonality of the tumor cell population. Polymerase chain reaction and subsequent sequence analysis of the K-ras-2 exon-1 gene was used for mutation analysis. Focal weak staining with p53 IHC was observed in 4 of 13 (31%) MS and 10 of 13 (77%) TS cases, with all remaining cases being negative (P < .05). Only one MS case (8%) showed K-ras mutation (codon 13 GGC > GAC; glycine > aspartate), which is in contrast to 2 of the TS cases (15%), showing codon 12 mutations. All the remaining cases were wild type. Therefore, primary mediastinal seminomas appear to be different in their K-ras sequence and p53 immunostain profile from TS. Codon mutation type may be useful in determining primary versus metastatic origin of a mediastinal seminoma.

Adolescent↗
PubMed1996

The role of apoptosis in bispecific antibody-mediated T-cell cytotoxicity.

In this report we describe the role of apoptosis in the process of tumour cell killing by bispecific monoclonal antibody (BsMAb)-redirected cytolytic T cells. The BsMAb used, BIS-1, has dual specificity for the CD3 complex on T cells and the pancarcinoma-associated 38 kDa transmembrane antigen EGP-2. BIS-1 allows activated T cells to specifically recognise and kill EGP-2-positive but not EGP-2-negative target cells. An assay was developed to quantify apoptosis in cells by separation of 3H-thymidine-labelled low-molecular, i.e. fragmented, from high-molecular, i.e. non-fragmented DNA. The presence of low molecular weight DNA was measured both within the target cells and in the cell-free supernatant. After exposure to BIS-1-redirected, -activated T cells, apoptosis was observed in EGP-2-positive target cells but not in EGP-2-negative target cells. Also no DNA fragmentation proved to be induced in the activated effector cells during assay. The degree of EGP-2-positive target DNA fragmentation depended on the concentration of BsMAb, the E/T ratio and the incubation time. Using a low E/T ratio (1/1), DNA fragmentation in and 51Cr release from target cells showed similar characteristics and kinetics. At higher E/T ratio (20/1), the 51Cr release from the target cells increased to a greater extent than the percentage fragmented target cell DNA. Inhibitors of DNA fragmentation added to the cytotoxicity assay inhibited not only DNA fragmentation, but also the release of chromium-51 from the target cells, suggesting that apoptosis and cell lysis are closely related in BsMAb-mediated cell killing.

Antibodies, Bispecific↗
PubMed1996

Prediction of Biologic Aggressiveness in Colorectal Cancer by p53/K-ras-2 Topographic Genotyping.

Background: Topographic genotyping is a system of solid tissue molecular analysis designed to correlate microscopic alterations with specific forms of gene damage. In this system, microscopic targets are selected on the basis of cellular and immunohistochemical features. Minute tissue samples corresponding to these targets are precisely removed and analyzed for the presence and specific type of oncogene/tumor suppressor gene damage by means of polymerase chain reaction (PCR) followed by DNA sequencing. In this study, topographic genotyping was used to investigate the prognostic value of p53 and K-ras-2 mutational damage in 204 patients with colorectal cancer from two tertiary care centers. Methods and Results: The intensity and distribution of p53 immunohistochemical staining were correlated with the presence and specific type of mutational change, which resulted in a better understanding of the highly variable nature of p53 immunostaining patterns. Molecular genotype was correlated with the depth and extent of colorectal cancer spread (Dukes B and C) and with survival for follow-up periods of up to 10 years. An algorithm for p53/K-ras-2 genotyping was formulated to include p53 immunohistochemistry and DNA sequencing both of p53 exons 5-8 and of K-ras-2 exons 1 and 2. By using this algorithm, survival was shown to be significantly better in those patients whose tumors manifested normal p53 and K-ras-2 genes (P >.01). Patients with p53-mutated tumors composed a poor prognostic group, characterized by a high rate of intra-abdominal recurrence in the form of peritoneal seeding. Patients with K-ras-2-mutated tumors also composed a poor prognostic group, marked by a tendency for distant hematogenous metastasis involving lung, bone, and brain. Conclusions: Topographic genotyping's molecular diagnostic approach to colorectal cancer combines immunohistochemistry, PCR, and DNA sequencing. It is informative, cost-effective, timely, and yet fully integrated with standard histopathology. The use of this approach by pathologists as a model system for molecular diagnosis of colorectal cancer and other forms of solid tumor malignancy is recommended. As new prognostic molecular lesions are documented for tumor progression and metastasis, topographic genotyping will be well suited to facilitate their clinical application.

Journal Article↗
PubMed1996

Relationship of p53 Genotype to Second-look Recurrence and Survival in Ovarian Epithelial Malignancy.

Background: Clinical stage at presentation and tumor status at second-look laparotomy are currently the best predictors of patient survival in epithelial ovarian carcinoma (EOC). Methods and Results: To evaluate the predictive value of genetic analysis, the presence and type of p53 mutation (p53 genotype) was determined in 76 patients treated for EOC between 1987 and 1992 and subjected to second-look laparotomy following initial treatment. Mutational analysis of p53 was performed retrospectively by means of topographic genotyping (TG), using formalin-fixed, paraffin-embedded tissue of the primary and recurrent tumor. In TG, minute tissue samples were dissected from unstained histologic sections, amplified for p53 exons 5-8 with the polymerase chain reaction (PCR), and then direct sequenced. The p53 genotype was correlated with tumor stage, histologic grade and type, tumor status at second look, and survival at 3 and 5 years. Mutational change involving p53 exons 5-8 was found in 41 of 76 tumors (54%), consisting of 29 cases manifesting missense alterations and 12 cases having truncations (deletions, insertions, or stop codons). Tumor mutational change for each patient was strictly limited to a single type, being identical in all recurrences of an individual primary cancer. Mutations of p53 were distributed over exons 5-8, with certain "hot spots" being evident (codons 220, 245, and 273). Mutational change was present in all stages of primary EOC, but was relatively more frequent in tumors of advanced stage (III and IV). Epithelial ovarian carcinoma manifesting p53 mutational damage was significantly more likely to show recurrence at second-look laparotomy (P <.001) and to have shorter survival at the 3- and 5-year follow-up (P <.001) evaluation. The predictive value of p53 genotype was independent of stage at presentation, histologic grade, or histopathologic type. Conclusions: Genotyping of p53 provides useful information on tumor aggressiveness and is an informative predictive marker of biologic tumor behavior, treatment response, and survival in EOC.

Journal Article↗
PubMed1996

Pleomorphic (giant and spindle cell) carcinoma is genetically distinct from adenocarcinoma and squamous cell carcinoma by K-ras-2 and p53 analysis.

Pleomorphic carcinoma (PC) of lung is a poorly differentiated epithelial neoplasm predominantly composed of pleomorphic giant and/or spindle tumor cells. The WHO classification of lung cancer recognizes spindle cell carcinoma and giant cell carcinoma as separate neoplasms related to squamous cell carcinoma (SqC) and large cell carcinomas, respectively. Further, the presence of foci of SqC or adenocarcinoma (AdC) in, respectively, 10% and 45% of PC produces additional uncertainty as to the distinctive nature of this tumor type. In this study, the authors tested the hypothesis that PC is an entity separate from SqC or AdC by evaluating the mutational spectrum seen in these tumor types. This is performed by documenting and comparing mutation type and rate of K-ras-2 and p53 genes in PC, SqC, and AdC. Comparative DNA sequence and immunohistochemical analysis were performed on 22 PC, 42 SqC, and 97 AdC. Archival formalin-fixed, paraffin-embedded tissues formed the basis of the study. Immunohistochemical staining with p53 antibody (DO-7) revealed statistically significant differences in the intensity and frequency of staining of PC (weak, 86% of cases) versus SqC (strong, 52% of cases) and AdC (strong, 27% of cases) (P < .001). Topographic genotyping with subsequent polymerase chain reaction (PCR) and sequence analysis of K-ras-2 showed mutations in significantly fewer cases of PC (9%, 2 of 22 cases) than in AdC (36%, 35 of 97 cases) or SqC (0%, 0 of 42 cases) (P < .001). Pleomorphic carcinoma also showed significantly fewer p53 point mutations (14%, 3 of 22 cases) than did AdC (27%, 26 of 97 cases) of SqC (43%, 18 of 42 cases) (P < .01). Finally, the p53 mutations in PC were more common in exon 7, whereas those in SqC and AdC were more frequent in exon 8. These findings reveal significant differences in the pattern and frequency of genetic mutations between PC and pulmonary SqC and AdC and are in keeping with the separate histopathologic classification of these tumors.

Adenocarcinoma↗
PubMed1996

Relationship of p53 gene alterations with tumor progression and recurrence in olfactory neuroblastoma.

Olfactory neuroblastoma (ONB) is a rare neuroectodermal tumor whose clinical course is not effectively predicted by initial stage or grade; p53 tumor suppressor gene alterations have not been determined concerning the ONB pathobiology and recurrence. We analyzed 18 formalin-fixed, paraffin-embedded ONB specimens (12 primary tumors and six recurrences or metastases) from 14 patients for p53 alterations using immunohistochemistry for p53 and WAF1 together with topographic genotyping (selection of minute tissue targets from unstained sections, PCR [polymerase chain reaction] amplification of exons 5-8 followed by direct DNA sequencing). Sequential material representing tumor recurrence or metastasis was available in four cases to compare genetic alterations over time in the same patient. None of the cases showed strong, diffuse p53 immunostaining. Focal weak to moderate intensity staining was evident in nine of 14 cases. Mutations in p53 were not detected in any of the cases, suggesting hyperexpression of p53 wild-type protein. Hyperexpression was further confirmed by correlation of WAF-1 and p53 immunopositivity. Importantly, in four cases with recurrence or metastasis, tumors manifested p53 wild-type hyperexpression. It appears that p53 point mutation does not play an important role in the initial development of ONB; however, p53 wild-type hyperexpression may occur in subsets of ONB likely to show local aggressive behavior and a tendency for recurrence. Wild-type p53 hyperexpression may be an important event in later stages of ONB growth and progression.

Adult↗
PubMed1996

Human T-cell leukemia virus type 2 Rex inhibits pre-mRNA splicing in vitro at an early stage of spliceosome formation.

The Rex protein is an essential regulator of RNA expression in human T-cell leukemia virus types 1 and 2 (HTLV-1 and HTLV-2) that promotes the accumulation of full-length and partially spliced viral transcripts in the cytoplasm. Rex-mediated regulation correlates with specific binding to a cognate RNA recognition element which overlaps the 5' splice site in the viral long terminal repeat. It has been unclear whether Rex directly affects splicing or only nuclear-to-cytoplasmic transport of viral mRNA. We demonstrate that HTLV-2 Rex is a potent inhibitor of splicing in vitro at an early step in spliceosome assembly. Inhibition requires phosphorylation of Rex and the ability of Rex to bind to the Rex response element. Direct inhibition of early spliceosome assembly by Rex may account for differential accumulation of unspliced transcripts and represents a novel mechanism of retroviral gene regulation.

Base Sequence↗
PubMed1996

Analysis of p53, K-ras-2, and C-raf-1 in pulmonary neuroendocrine tumors. Correlation with histological subtype and clinical outcome.

Neuroendocrine tumors of lung, including typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell lung carcinoma (SCLC) constitute a spectrum of malignancies in which the pathologist at times has difficulty in discerning tumor subtype and aggressiveness in a reproducible fashion. Therefore, 59 primary neuroendocrine lung tumors including 10 TCs, 26 ACs, 15 LCNECs, and 8 SCLCs were selected from cases collected from 1976 to 1988 and immunostained for p53 protein. All of these tumors were also genotyped for specific point mutational damage affecting p53 (exons 5, 7, and 8; with ACs additionally sequenced for p53 exon 6); 13 tumors for K-ras-2 (exon 1); and 31 tumors for c-raf-1 (exon 15) growth-regulatory genes. Genotyping was performed on topographically selected, minute tumor samples removed from unstained formalin-fixed, paraffin-embedded tissue sections (topographic genotyping) using polymerase chain reaction and direct sequencing. The distribution of p53 immunohistochemical staining had four patterns: negative in TCs, one-half of ACs, 3 of 15 LCNECs, and 1 of 8 SCLCs; less than 10% but more than five tumor cells per 10 high power fields (focal) in a subset (7 of 26) of aggressive ACs; 10 to 49% of tumor cells (patchy) in a subset (6 of 26) of ACs with a higher grade of aggressiveness; and 50 to 100% of tumor cells (diffuse), exclusively seen in LCNECs (12 of 15) and SCLCs (7 of 8). Three patterns of immunohistochemical staining intensity of p53 protein were seen: negative, weak or mild, and moderate to marked. SCLCs and LCNECs accounted for cases of moderate to marked staining and were the only ones to have mutations in p53 exons 5, 7, or 8. No mutations were found in AC and TC, showing absent to weak staining and no staining, respectively. The difference in distribution and staining intensities between LCNEC and SCLC compared with AC and TC was statistically significant (P < 0.001). Patients having AC with patchy p53 immunostaining usually had survival limited to 3 years, whereas those having AC with focal p53 immunostaining subsequently developed metastatic or recurrence of AC disease (P < 0.05). The absence of point mutations in cases with patchy or focal immunostaining suggests increased expression of wild-type p53 tumor suppressor protein likely in response to growth deregulation in a more aggressive subtype of AC. A novel hypothesis is presented in regard to these findings. K-ras-2 and c-raf-1 gene sequence analysis showed no evidence of point mutational change in any of the tumors studied. The TC and AC categories are therefore genetically distinct from the higher grade neuroendocrine SCLC and LCNEC. Immunohistochemistry for p53 on AC lung tumors may be helpful to delineate cases at higher risk for aggressive behavior. Additionally, although LCNEC is categorized as a non-small-cell carcinoma, it is more akin genetically and immunohistochemically to SCLC.

Carcinoid Tumor↗
PubMed1996

K-ras-2 and p53 genotyping of intestinal-type adenocarcinoma of the nasal cavity and paranasal sinuses.

Intestinal-type adenocarcinoma (ITAC) of the nasal cavity and paranasal sinuses is an uncommon neoplasm manifesting a variety of histologic growth patterns, most of which are reminiscent of colorectal adenocarcinoma. To determine whether this morphologic resemblance is mirrored in equivalent genetic alterations, a series of ITAC was genotyped using archival, formalin-fixed tissues for point mutational damage in K-ras-2 oncogene and p53 tumor suppressor gene, forms of DNA damage frequently found in colorectal adenocarcinoma. In contrast to colorectal adenocarcinoma, which demonstrates K-ras-2 mutation in about 50% of cases, ITAC showed no evidence of K-ras-2 mutation. p53 mutations were present in 18% of ITAC (2 of 11) compared to more than 75% incidence of p53 mutation seen in colorectal adenocarcinoma. Fifty-eight percent of ITAC demonstrated scattered positive p53 immunohistochemical nuclear staining, but no mutations were identified in exon-5 through exon-8 by genotyping. There was no specific p53 alterations with respect to histologic subtype of ITAC. Although ITAC and colorectal adenocarcinoma are histologically similar, there are important differences at the genetic level based on expression of K-ras-2 and p53 abnormalities.

Adenocarcinoma↗
PubMed1996

Applications of laser microprobe mass spectrometry in biology and medicine.

Laser microprobe mass spectrometry (LMMS) provides spot analysis with a lateral resolution of 1-5 microns. Focused laser ionisation, combined with mass spectrometry, yields information on elements, molecular identification of inorganic substances, and structural characterisation of organic molecules of typically less than 2-3 kDa. Quantification in complex heterogeneous systems, such as biological materials, is not possible at the present state of the art. The strength of the method lies in the qualitative information on the molecular composition of the analyte, not just element detection, with a lateral resolution at the light microscopy level. The applications of this technique in the field of biomedicine and biology are illustrated by examples that demonstrate the use of this qualitative information in practical test cases.

Fourier Analysis↗
PubMed1995

Bispecific antibody-mediated target cell-specific costimulation of resting T cells via CD5 and CD28.

Induction of T-cell activation requires multiple signals provided by cell surface receptor interactions and/or cytokines. T-cell stimulation via the T-cell receptor/CD3 complex provides an important initial activation event which, when combined with the proper costimulatory signals, results in an activated effector T cell. In this report, we have investigated the effectiveness of epithelial glycoprotein-2- (EGP-2) positive tumor target cells to induce specific T-cell stimulation via CD3, CD5, and CD28 using various combinations of bispecific monoclonal antibodies (BsMab) directed against CD3, CD5, or CD28 on the one hand and the pancarcinoma-associated antigen EGP-2 on the other. Induction of T-cell activation was investigated by assessment of CD69 expression, induction of proliferation, and acquirement of cytolytic potential. EGP-2-specific induction of T-cell activation was observed using combinations of BsMab which simultaneous ligated CD3/CD5, CD3/CD28, or CD3/CD5/CD28 with EGP-2. Activation with CD3-, CD5-, or CD28-based BsMab alone did not result in significant induction of T-cell activation in the presence or absence of EGP-2-positive target cells. Simultaneous ligation via CD5/CD28 resulted in partial T-cell activation, including CD69 up-regulation and increased cytolytic activity. Stimulation via CD3 and CD5 or CD28 could be further increased by the addition of exogenously added recombinant Interleukin 2. In contrast, T-cell activation by simultaneous ligation of CD3/CD5/CD28 could not be further augmented by addition of exogenous interleukin 2, indicating that T-cell activation via the combination of CD3, CD5, and CD28 results in complete T-cell activation. Our results show that rapid and target cell-specific induction of T cells is possible using combinations of BsMab directed against different costimulatory molecules. Simultaneous costimulation via CD3/CD5/CD28 results in the most complete activation of T cells.

Antibodies, Bispecific↗
PubMed1995

Benzodiazepines and the risk of falling leading to femur fractures. Dosage more important than elimination half-life.

BACKGROUND: In the past decade, the use of benzodiazepines has been identified as a major independent risk factor for accidental falls. OBJECTIVE: To study the role of dosing, timing, elimination half-life, and type of benzodiazepine in relation to the occurrence of accidental falls leading to hospitalization for femur fractures. METHODS: A 1:3 age-, sex-, and pharmacy-matched case-control study was performed using data from a Dutch record linkage system (PHARMO) (N = 300,000). Cases included 493 patients (55 years and older), newly admitted to the hospital for a femur fracture resulting from an accidental fall (between 1986 and 1992). Relative risk estimates were calculated using conditional logistic regression analyses to control for the potential confounding effects of concomitant drug use and presence of a wide range of underlying diseases. RESULTS: Falls were significantly associated with current use of benzodiazepines (odds ratio, 1.6; 95% confidence interval, 1.2 to 2.1) and in particular with short half-life benzodiazepines (odds ratio, 1.5; 95% confidence interval, 1.1 to 2.0), sudden dose increases (odds ratio, 3.4; 95% confidence interval, 1.0 to 11.5), and concomitant use of several benzodiazepines (odds ratio, 2.5; 95% confidence interval, 1.3 to 4.9). A strong dose-response relationship (P < .0001) and dose-response relations among users of either short or long half-life benzodiazepines suggests that these increased risks are explained primarily by dose. CONCLUSIONS: Benzodiazepines are a major, independent risk factor for falls leading to femur fractures, and the increased risk is probably explained by prescribing too-high doses to the elderly.

Accidental Falls↗