Biomedical subjects

L Wilkens

Publications and source records attributed to L Wilkens.

At least 19 recordsLinked to original sources

PubMed1998

Standard calculation of ethanol elimination rate is not sufficient to provide ethanol substitution therapy in the postoperative course of alcohol-dependent patients.

OBJECTIVE: Alcohol withdrawal syndrome (AWS) is a severe complication during postoperative treatment of alcohol-dependent patients. Besides the use of clomethiazole, clonidine, and benzodiazepines, there is another possible way to prevent AWS by deliberate administration of ethanol. The appropriate dosage of ethanol has not been known up to now and it could be defined according to the average ethanol elimination rate (EER) which, from forensic analysis, is known to be 15 mg/dl per h in a normal population. However, it is questionable whether these data are suitable for the calculation of the correct dosage in alcohol-dependent patients. DESIGN: Preliminary retrospective descriptive study. SETTING: Intensive care unit of a university teaching hospital. PATIENTS: 11 alcohol-dependent patients (9 males, 2 females, mean age 50.8 years, range 33 to 60 years). INTERVENTIONS: Ethanol substitution (ES) by parenteral application. MEASUREMENTS AND RESULTS: Ethanol kinetics were evaluated by repeated measurement of the blood ethanol concentration (BEC) over a period of at least 6 h parallel to the administration of ethanol. The average EER was found to be 28 mg/dl per h with a standard deviation of 11 mg/ dl per h. The minimum value was 18 mg/dl per h and the maximum 50 mg/dl per h. These EERs were significantly higher than the EERs known from forensic analysis. AWS was prevented in all 11 patients. CONCLUSIONS: Close control of BEC and precise adjustment of ethanol administration are necessary prerequisites for ES. The standard EER is not sufficient to define the appropriate ethanol dosage due to enormous variations in the ethanol metabolism of alcohol-dependent patients.

Adult↗

PubMed1998

Analysis of hematologic diseases using conventional karyotyping, fluorescence in situ hybridization (FISH), and comparative genomic hybridization (CGH).

Comparative genomic hybridization (CGH) has been proven to be an important tool in interphase cytogenetics of solid tumors. Although, because of methodological implications, balanced aberrations are not detected by CGH, the technique has uncovered a variety of new and interesting imbalanced karyotype changes. However, only a few studies deal with its application to hematologic disorders, although this is a main topic of cytogenetics. The aim of our study was, therefore, to evaluate the usefulness of CGH in the examination of hematologic neoplasms. For this purpose, bone marrow aspirates of 33 patients with different hematologic disorders were examined with CGH and the results compared with conventional cytogenetics (CC) and fluorescence in situ hybridization (FISH). CGH showed chromosome changes in 8 of 33 cases. CC found balanced aberrations in 4 of 33 and unbalanced changes in 9 of 33 samples. Differences between CGH and CC in unbalanced aberrations were seen in four cases. In these samples, either the number of aberrant cells found by CC was low and, therefore, difficult to detect by CGH, or complex aberrations in different cell clones as seen in CC were lumped together as one karyotype by CGH. In one sample, CC was not capable of giving any results at all, whereas CGH showed trisomy 8. CGH was also helpful in defining the bands involved in the structural aberrations, which was difficult by CC in some cases because of the low quality of metaphase spreads. All results obtained by CGH were confirmed by FISH, whereas CC and FISH were discordant in one case. Although CGH was not able to detect all aberrations, it gave important additional information for the correct localization of the aberrations found in CC, and it was most helpful in samples not processed successfully in CC. These advantages would open up a new field of application for CGH not only for research, but also for diagnostic purposes.

Adult↗

PubMed1998

Fluorescence in situ hybridization and surface markers of fine needle aspiration specimen confirm extramedullary myeloblastoma in a patient with chronic myeloid leukemia.

We report on a patient with chronic myeloid leukemia (CML) with a rapidly growing left cervical tumor 5 months after the initial diagnosis of CML. This tumor was diagnosed as a very early manifestation of extramedullary myeloblastoma by a minimally invasive method. A fine needle aspirate (26-gauge needle) was obtained from the tumor. Morphological and cytochemical analysis of the aspirate revealed 19% undifferentiated blasts. The immunophenotype was suggestive of a myeloid differentiation of the blasts (CD33+). The CML origin of the blasts was confirmed by the detection of the bcr-abl gene rearrangement in the blasts by two-color fluorescence in situ hybridization (FISH). We conclude that fine needle aspiration in combination with immunophenotyping and FISH analysis of the aspirate is a minimally invasive and rapid diagnostic tool to confirm extramedullary manifestation in CML. To our knowledge, this is the first case of extramedullary myeloblastoma confirmed by this combined technique.

Adult↗

PubMed1997

Rapid detection of karyotype changes in interphase bone marrow cells by oligonucleotide primed in situ hybridization (PRINS).

Fluorescence in situ hybridization (FISH) using DNA probes of several hundred or thousand base pairs in length enables the visualization of chromosomal aberrations in interphase nuclei. A new method for in situ labelling of chromosomes is the oligonucleotide primed in situ labelling (PRINS) technique. So far, this has mainly been used to demonstrate subtle changes in metaphase spreads. The aim of the present study was to investigate the suitability of PRINS for detecting chromosome gains or losses in interphase nuclei. This technique was compared with FISH analysis by examining the bone marrow cells of ten patients in whom the karyotypes were known from conventional chromosome banding. Corresponding results by both PRINS and FISH were obtained for chromosomes 1, 3, 7, 8, and Y in five patients with normal chromosome patterns, as well as in five patients with clonal karyotype changes, e.g., monosomy 7, trisomy 8, or loss of the Y chromosome. Being faster and approximately ten times less expensive, PRINS can replace FISH for detecting numerical karyotype changes.

Adult↗

PubMed1997

Detection of karyotype changes in interphase cells: oligonucleotide-primed in situ labelling versus fluorescence in situ hybridization.

Interphase cytogenetics is a rapidly developing technique which is usually performed by fluorescence in situ hybridization (FISH). Recently, oligonucleotide-primed in situ synthesis (PRINS) has become established as a method of labelling centromeric regions of chromosomes in metaphase spreads. We tested the suitability of PRINS in detecting the exact copy number of chromosomes 1, 3, 7 and 8 in intact interphase cells of 17 cytological preparations derived from normal and neoplastic tissues. Control procedures consisted in preparation of metaphase spreads of lymphocytes of healthy donors, conventional cytogenetics in some of the specimens, and omission of the primers or Taq polymerase from the reaction mixture. All specimens were additionally examined by FISH and analysed blind by two experienced observers. Both PRINS and FISH revealed a corresponding distribution of hybridization signals for all chromosomes examined in specimens of normal bone marrow (n = 5), normal liver cells (n = 5), three samples of acute nonlymphocytic leukaemia in which conventional chromosome analyses had shown monosomy 7 or trisomy 8, and in four hepatocellular carcinomas that displayed trisomy 1. Overall, statistical analysis revealed no significant difference in the signal distribution between the two techniques. Our results demonstrate that PRINS is as reliable as FISH for detecting chromosome copy numbers in interphase nuclei of intact cells. The PRINS method, however, is easier to perform, faster and less expensive, holding great potential for future applications in diagnostic pathology.

Biopsy↗

PubMed1997

Low-dimensional dynamics in sensory biology. 1: Thermally sensitive electroreceptors of the catfish.

We report the results of a search for evidence of periodic unstable orbits in the electroreceptors of the catfish. The function of these receptor organs is to sense weak external electric fields. In addition, they respond to the ambient temperature and to the ionic composition of the water. These quantities are encoded by receptors that make use of an internal oscillator operating at the level of the membrane potential. If such oscillators have three or more degrees of freedom, and at least one of which also exhibits a nonlinearity, they are potentially capable of chaotic dynamics. By detecting the existence of stable and unstable periodic orbits, we demonstrate bifurcations between noisy stable and chaotic behavior using the ambient temperature as a parameter. We suggest that the technique developed herein be regarded as an additional tool for the analysis of data in sensory biology and thus can be potentially useful in studies of functional responses to external stimuli. We speculate that the appearance of unstable orbits may be indicative of a state of heightened sensory awareness by the animal.

Animals↗

PubMed1997

[Postoperative therapy of an alcoholic patient with an unusually high ethanol metabolic rate].

To avoid alcohol withdrawal syndrome (AWS) a pre-operative withdrawal, post-operative drug therapy or continued substitution of ethanol may be tried. However, substitution of ethanol needs an exact dosage and has to be controlled very carefully. The dose calculation is based on an assumed breakdown rate of 0.15 g%/1000/h, as evaluated in forensic studies. We report on a patient who throws the basis for these calculations into question. The breakdown rate of this 43-year-old man was extraordinary higher than the average turnover. This high level of the turnover rate occurred with no detectable impairment of the liver or other organs. This case demonstrates the importance of a close control of the blood alcohol level during the post-operative administration of ethanol. The individual doses of ethanol to avoid AWS has to be found individually for each patient.

Adult↗

PubMed1997

Ethnic differences and factors related to breast cancer survival in Hawaii.

BACKGROUND: Previous studies have described differences in breast cancer survival among women from various ethnic backgrounds even after adjustment for stage at diagnosis. The aim of this study is to identify factors that could explain this disparity in prognosis and to update breast cancer survival patterns in Hawaii. METHODS: The Hawaii Tumor Registry identified 3345 breast cancer cases diagnosed between 1980 and 1988. The following covariates were studied: ethnicity, stage at diagnosis, geographical residence, and menopausal, marital and socioeconomic statuses. The Kaplan-Meier method and proportional hazards regression were used to estimate survival by group. RESULTS: Native Hawaiian and Filipino women had a higher risk of dying within 5 years than women of other ethnic groups. Japanese had the highest survival probability, followed by Chinese and Caucasians. Stage was the most important prognostic factor. Married women had better survival than widowed and divorced women. Filipinos had a much greater chance of dying from localized cancer than other women with localized disease. Geographical residence, menopausal and socioeconomic statuses were not associated with survival. CONCLUSIONS: Despite an overall improvement in breast cancer survival, ethnic disparity in prognosis still exists. Other possible explanations for the differential prognosis, such as treatment, diet, genetics, obesity, oestrogen receptor and hormonal statuses need to be explored in future studies.

Adult↗

PubMed1997

Value of fluorescence in situ hybridization for detecting the bcr/abl gene fusion in interphase cells of routine bone marrow specimens.

Fluorescence in situ hybridization (FISH) is a new technique that allows demonstrating of the bcr/abl gene fusion in bone marrow cells of patients with Philadelphia translocation (Ph)-positive chronic myeloid leukemia (CML). In this study, bone marrow samples of 150 patients were investigated routinely by interphase FISH, cytogenetics, and bone marrow histopathology. In 20 patients with reactive hyperplasia of the granulopoiesis and normal karyotypes, FISH revealed nonspecific bcr/abl fusion signals at a mean frequency of 2.7% of the cells examined. The cutoff level for specific fusion signals was set at three times the standard deviation (9.0%). None of the 29 cytogenetically Ph-negative patients with myeloproliferative disease other than CML had fusion signals exceeding 9%. The mean frequency of specific fusion signals in nontreated patients with CML (n = 59) was 92.7%, and 49.3% in patients with CML who received therapy (n = 42). For diagnosing Ph-positive CML, interphase FISH has been faster, more reliable, and more sensitive than cytogenetics, which was successful in 54 of 59 patients investigated at first diagnosis but only in 27 of 42 patients receiving therapy, and it failed to detect Ph-positive cells in three patients with CML. However, small percentages of less than 9.0% of cells with bcr/abl fusion signals were below the threshold of interphase FISH, thereby limiting its use for detecting minimal residual disease.

Aged↗

PubMed1997

Tyramine amplification technique in routine immunohistochemistry.

Signal amplification in immunohistochemistry via binding of biotinylated tyramine to proteins near the site of peroxidase-labeled antibodies is a promising new technique, but studies investigating a wide range of markers are lacking. The tyramine amplification technique (TAT) was investigated on 85 antibodies using a simple and fast protocol, and TAT results were compared to those obtained with conventional immunohistochemistry. Using TAT, most of the markers could be 5- to 50-fold further diluted and still showed identical staining results compared with standard stainings (maximal 500-fold). However, the variable reactivity of the different markers with TAT underlines the need for individual testing of every antibody to determine the optimal dilution. Some antibodies against cell adhesion molecules could be demonstrated for the first time in archival, formalin-fixed tissue sections. TAT, if carefully evaluated, offers a revolutionary improvement for modern immunostaining, either to increase sensitivity or primary antibody dilutions (cost reduction). From a methodological point of view, immunohistochemistry has not reached its limits by far and TAT is an important progressive step in this developmental process.

Antibodies, Monoclonal↗

PubMed1997

Mammography screening and the increase in breast cancer incidence in Hawaii.

This ecological study investigated the association between mammography utilization and breast cancer incidence in Hawaii with the hypothesis that geographic areas with high mammography use have higher breast cancer incidence than geographic areas with low mammography use. Insurance claims for mammograms received during 1992 and 1993 were combined with breast cancer incidence data from the Hawaii Tumor Registry and data from the 1990 Census ZIP File. The claims data were obtained from four private and three public health plans and covered approximately 85% of women 40 years of age and older. Age-specific breast cancer incidence rates for the 79 ZIP code areas were regressed on mammography rates and selected aggregate demographic variables using multiple linear regression. An estimated 42% of women 40 years of age and older had received at least 1 mammogram during 1992 and 1993, with the highest rate (45%) in women ages 50-64 years old. Overall, 23% of the variation in age-specific breast cancer incidence could be predicted by mammography utilization, 23% by increasing age, and 4% by higher education. The relationship between mammography use and breast cancer incidence was strongest for women 50-64 years old and for localized disease. The magnitude of the association between breast cancer incidence and mammography utilization was comparable to the increase in breast cancer rates observed in Hawaii during the mid-1980s, supporting the hypothesis that the sharp increase in breast cancer incidence was attributable to screening and early detection. However, the long-term 1% increase in breast cancer incidence requires alternate explanations.

Adult↗

PubMed1997

Applications of single-color and double-color oligonucleotide primed in situ labeling in cytology.

Interphase cytogenetics is mostly performed with use of fluorescence in situ hybridization (FISH), using long DNA probes of several hundred or thousand base pairs in length. Recently, oligonucleotide primed in situ labeling (PRINS) was established for staining centromeres and telomeres of chromosomes in metaphase spreads by Taq-polymerase-mediated incorporation of labeled nucleotides. We investigated the use of PRINS in intact interphase cells of various cytologic preparations, targeting chromosomes 1, 8, and 9. Examining cell smears (n = 3), touch preparations (n = 20), and cytospins (n = 11) of non-neoplastic and neoplastic tissues, PRINS was as sensitive and reliable as the FISH method in assessing the exact chromosome number. Aneuploidy in tumor cells was confirmed by double-color PRINS in a part of the specimens. The PRINS reaction, which requires heating of the cell preparations to as high as 96 degrees C, did not affect the cytomorphologic details. Because PRINS is much faster and approximately 10 times less expensive than FISH, this method allows an increased application of interphase cytogenetics in diagnostic cytopathology.

Aneuploidy↗

PubMed1996

Detection of numerical karyotype changes in the giant cells of Hodgkin's lymphomas by a combination of FISH and immunohistochemistry applied to paraffin sections.

Conventional karyotyping of Hodgkin's disease (HD) has until now yielded only limited insight into karyotypic characteristics of this disease. For this reason, fluorescence in situ hybridization (FISH) using alpha-satellite chromosome-specific probes was applied to paraffin sections of HD tumors in order to verify numerical aberrations suggested to be specific for HD in the literature. The FISH technique was combined with immunohistochemical detection of the CD30 antigen to allow easier identification of the Reed-Sternberg and Hodgkin (RS&H) cells. The number of specific FISH signals per nucleus was determined both in CD30-positive RS&H cells as well as in non-malignant "bystander" cells in order to assess differences in the signal distribution. Contrasted with normal lymphoid cells, the tumor cells in HD were found to be polysomic for at least one of the chromosomes analyzed (1,2,4, and 8). The technique described is a reliable method for confirmation of results obtained from conventional cytogenetics, which is especially suited for archival material or samples not containing dividing cells.

Antigens↗

PubMed1996

Microwave pretreatment improves RNA-ISH in various formalin-fixed tissues using a uniform protocol.

RNA is situ hybridization technique (RNA-ISH) is hampered by formalin fixation of tissues. This necessitates a pretreatment step of enzymatic digestion. However, to achieve the best results, digestion times and concentrations of enzymes have to be adapted for every specimen in a cumbersome procedure. Microwave pretreatment (MP) of formalin-fixed tissues has developed to become a powerful tool in immunohistochemistry (IHC) in recent years. To evaluate whether MP could also be helpful for RNA-ISH, we compared MP and conventional enzymatic pretreatment systematically using different tissues and various fixation times. As a model for RNA-ISH we chose the detection of kappa/lambda light chain mRNA in tonsils and lymph nodes with follicular hyperplasia and lymph nodes of patients with lymphocyte predominant Hodgkin's Disease (LPHD). Signal intensity obtained after MP was at least as good or dramatically enhanced as that obtained with optimized, single case adapted conventional pretreatment, the morphology being much better preserved after MP. These results confirm MP as a suitable method to unify the staining protocols in RNA-ISH, regardless of the duration of formalin fixation. Based on our results we recommend MP as a reliable and inexpensive method to enhance, standardized and simplify RNA-ISH.

Formaldehyde↗

PubMed1996

Fluorescence in situ hybridization (FISH) is a reliable diagnostic tool for detection of the 9;22 translocation.

The fluorescence in situ hybridization (FISH) technique for detection of the 9;22 translocation was compared with the "gold standard" of conventional cytogenetics. For this purpose, both methods were applied to 81 bone marrow aspirates and/or peripheral blood specimens comprising 50 CML cases and controls from 31 patients without CML. Independently, core biopsies of these 81 patients were investigated by three histopathologists. Conventional karyotype analysis from unstimulated bone marrow cells was successful in 71/81 cases and demonstrated the Ph-chromosome in 42/46 CML patients. With FISH, results were obtained in all 81 cases investigated, confirming fusion of the ber and abl genes in all cytogenetically Ph-positive patients. Among the five Ph-chromosome-negative specimens bcr/abl fusions were detected in only one patient. The percentage of cells found to be Ph-positive by both methods was correlated, but in individual cases considerable differences in the numbers of Ph-positive cells were observed. Different results may be due to selection of cells after in vitro cultivation predominantly. FISH proved to be a very reliable technique for specimens that do not contain dividing cells. With FISH, large numbers of cells can easily be scored which is an advantage compared to conventional cytogenetics. Therefore, this method is particularly suitable for those whose therapy is being monitored or a relapse is suspected. However, the FISH results should be evaluated critically with respect to the practical limit of sensitivity since non-specific fusion signals can also be observed in a small percentage of cells in non-CML cases. It is suggested that each laboratory define its own threshold of bcr/abl fusion signals for diagnosing Ph-positive CML by FISH.

Adolescent↗

PubMed1996

Light-chain mRNA in lymphocyte-predominant and mixed-cellularity Hodgkin's disease.

There is growing evidence for a B-cell lineage of lymphocyte-predominant Hodgkin's disease (1). To support this assumption, in situ hybridization techniques were used to detect immunoglobulin light-chain mRNA in 44 formalin-fixed specimens of Hodgkin's lymphoma (22 of lymphocyte-predominant Hodgkin's disease; 22 of mixed-cellularity Hodgkin's disease). In addition, immunoglobulin light chains were evaluated by polyclonal antisera. All specimens had been unequivocally diagnosed histologically by the referees of the German Hodgkin Trial and been immunophenotyped by monoclonal antibodies against CD15, CD20, CD30, and CD45. Light-chain mRNA coding either for kappa or for lambda could be detected by an enhanced in situ hybridization protocol using microwave heating in the lymphocytic and histiocytic cells of 14 (64%) of 22 specimens of lymphocyte-predominant Hodgkin's disease tested. None of the specimens, however, belonging to one of the classic subtypes of Hodgkin's disease (mixed-cellularity Hodgkin's disease) showed positivity for mRNA in the giant tumor cells. Our results support the idea that lymphocyte-predominant Hodgkin's disease represents a B-cell malignancy that is a entity separate from classic Hodgkin's disease. Diverging results of former studies in assessing light-chain mRNA in lymphocytic and histiocytic cells probably reflect problems with the detection threshold, i.e., the sensitivity of the techniques applied.

Hodgkin Disease↗

PubMed1995

The bcl-2/JH gene rearrangement is undetectable in Hodgkin's lymphomas: results from the German Hodgkin trial.

Ninety-one Hodgkin's lymphomas (HD), 52 non-Hodgkin lymphomas (NHL) and 33 specimens of non-neoplastic lymphatic tissues were investigated by polymerase chain reaction (PCR) for the presence of the bcl-2/JH gene rearrangement. The majority of the HD cases were drawn from the files of the German Hodgkin trial where diagnoses are established by a panel of four independent histopathologists. Using the very sensitive PCR method which detected 1 positive among 10000 negative cells, the bcl-2/JH gene rearrangement was found in 7/52 NHL and 3/16 tonsils with follicular hyperplasia, but in none of the 91 HD. The bcl-2 protein, however, was expressed by malignant cells of B and T cell lymphomas and by the giant tumour cells in 2/13 HD lymphocyte predominant, 11/28 HD nodular sclerosing I, 14/17 HD nodular sclerosing II, 10/27 HD mixed cellularity and 3/3 HD lymphocyte depleted. The bcl-2/JH rearrangement is thus independent of protein over-expression, the latter being found in all types of lymphomas. Our results do not confirm the findings of others who have detected the bcl-2/JH rearrangement in HD. These discrepancies may be explained by differences in choice of material, the gene rearrangement actually occurring in bystander cells but not in Reed-Sternberg or Hodgkin cells, or by contamination.

Chromosomes, Human, Pair 18↗

PubMed1995

Demonstration of the Philadelphia translocation by fluorescence in situ hybridization (FISH) in paraffin sections and identification of aberrant cells by a combined FISH/immunophenotyping approach.

The Philadelphia translocation was demonstrated by two-colour fluorescence in situ hybridization (FISH) in decalcified paraffin sections of bone marrow from patients with chronic myelogenous leukaemia. FISH was combined with immunocytochemical detection of different membrane-bound or cytoplasmic antigens. With this new technique, the cells bearing the 9:22 translocation can be identified morphologically, as well as immunocytochemically, in tissue sections.

Antigens, CD↗