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D Pfeifer

Publications and source records attributed to D Pfeifer.

At least 19 recordsLinked to original sources
PubMed2006

The Calibration Kit Spectral Fluorescence Standards--a simple and certified tool for the standardization of the spectral characteristics of fluorescence instruments.

With the Calibration Kit Spectral Fluorescence Standards BAM-F001-BAM-F005, we developed a simple tool for the characterization of the relative spectral responsivity and the long-term stability of the emission channel of fluorescence instruments under routine measurement conditions thereby providing the basis for an improved comparability of fluorescence measurements and eventually standardization. This first set of traceable fluorescence standards, which links fluorescence measurements to the spectral radiance scale in the spectral range of 300-770 nm and has been optimized for spectrofluorometers, can be employed for different measurement geometries and can be adapted to different fluorescence techniques with proper consideration of the underlying measurement principles.

Calibration↗
PubMed2005

Traceability in fluorometry--Part I: Physical standards.

The inter-instrument, inter-laboratory, and long-term comparability of fluorescence data requires the correction of the measured emission and excitation spectra for the wavelength- and polarization-dependent spectral irradiance of the excitation channel at the sample position and the spectral responsivity of the emission channel employing procedures that guarantee traceability to the respective primary standards. In this respect the traceability chain of fluorometry is discussed from a radiometrist's point of view. This involves, in a first step, the realization of the spectral radiance scale, based on the blackbody radiator and electron storage ring, and the spectral responsivity scale, based on the cryogenic radiometer and their control via key comparisons of the national metrology institutes. In a second step, the characterization including state-of-the art uncertainties of the respective source and detector transfer standards such as tungsten strip lamps, integrating sphere radiators, and trap detectors used to disseminate these radiometric quantities to users of spectroscopic techniques is presented.

Journal Article↗
PubMed2005

Traceability in fluorometry: Part II. Spectral fluorescence standards.

The need for the traceable characterization of fluorescence instruments is emphasized from a chemist's point of view, focusing on spectral fluorescence standards for the determination of the wavelength- and polarization-dependent relative spectral responsivity and relative spectral irradiance of fluorescence measuring systems, respectively. In a first step, major sources of error of fluorescence measurements and instrument calibration are revealed to underline the importance of this issue and to illustrate advantages and disadvantages of physical and chemical transfer standards for generation of spectral correction curves. Secondly, examples for sets of traceable chemical emission and excitation standards are shown that cover a broad spectral region and simple procedures for the determination of corrected emission spectra with acceptable uncertainties are presented. With proper consideration of the respective measurement principle and geometry, these dye-based characterization procedures can be not only applied to spectrofluorometers but also to other types of fluorescence measuring systems and even to Raman spectrometers.

Journal Article↗
PubMed2001

Comparative genomics of the SOX9 region in human and Fugu rubripes: conservation of short regulatory sequence elements within large intergenic regions.

Campomelic dysplasia (CD), a human skeletal malformation syndrome with XY sex reversal, is caused by heterozygous mutations in and around the gene SOX9. SOX9 has an extended 5' control region, as indicated by CD translocation breakpoints scattered over 1 Mb proximal to SOX9 and by expression data from mice transgenic for human SOX9-spanning yeast artificial chromosomes. To identify long-range regulatory elements within the SOX9 5' control region, we compared approximately 3.7 Mb and 195 kb of sequence around human and Fugu rubripes SOX9, respectively. We identified only seven and five protein-coding genes in the human and F. rubripes sequences, respectively. Four of the F. rubripes genes have been mapped in humans; all reside on chromosome 17 but show extensive intrachromosomal gene shuffling compared with the gene order in F. rubripes. In both species, very large intergenic distances separate SOX9 from its directly flanking genes: 2 Mb and 500 kb on either side of SOX9 in humans, and 68 and 97 kb on either side of SOX9 in F. rubripes. Comparative sequence analysis of the intergenic regions revealed five conserved elements, E1-E5, up to 290 kb 5' to human SOX9 and up to 18 kb 5' to F. rubripes SOX9, and three such elements, E6-E8, 3' to SOX9. Where available, mouse sequences confirm conservation of the elements. From the yeast artificial chromosome transgenic data, elements E3-E5 are candidate enhancers for SOX9 expression in limb and vertebral column, and 8 of 10 CD translocation breakpoints separate these elements from SOX9.

5' Flanking Region↗
PubMed2001

Evaluation of outcomes in converting from intravenous ondansetron to oral granisetron: an observational study.

OBJECTIVE: To describe a systematic evaluation of the outcomes associated with revising institutional guidelines for the prevention of acute chemotherapy-induced nausea and vomiting (CINV) to promote cost-effective use of the serotonin (5-HT3) antagonists. METHODS: The 5-HT3 antagonist of choice in the antiemetic guidelines was revised from intravenous ondansetron to oral granisetron in August 1995. Patient assessments were conducted immediately prior to (Period 1) and after (Period 2) guideline revision using validated questionnaires. The effectiveness of the two 5-HT3 antagonists were compared and reported to the prescribing oncologists. Outcomes were assessed one year after guideline revision (Period 3) using identical methods. RESULTS: No difference was found in the rate of total control (no emesis, no nausea) between patients receiving oral granisetron (60%) and intravenous ondansetron (56%) (p = 0.408, Period 1 vs. 2). Nausea severity, the number of emesis episodes, and use of rescue antiemetics were also equivalent. Prescriber compliance with using the 5-HT3 antagonist of choice and dose increased from 48% to 61% following adoption of oral granisetron. By Period 3, compliance increased to 78%, and satisfactory control of acute CINV was again documented. The costs for prevention of acute CINV decreased from $107 in Period 1 (intravenous ondansetron only) to $65 in Period 3 (oral granisetron). CONCLUSIONS: Outcomes associated with use of oral granisetron and intravenous ondansetron were equivalent in this patient population. Guideline revision and outcome documentation by the oncology pharmacists resulted in increased compliance with institution guidelines and a 40% cost savings.

Administration, Oral↗
PubMed2000

The SOX8 gene is located within 700 kb of the tip of chromosome 16p and is deleted in a patient with ATR-16 syndrome.

SOX proteins are transcription factors that are characterized by a common DNA-binding motif known as the HMG domain. We describe the 5. 4-kb human SOX8 gene that codes for a 446-amino-acid protein and that is expressed strongly in brain and less abundantly in other tissues. SOX8 shows an overall identity of 47% to SOX9 and SOX10. The latter two possess a C-terminal transactivation domain, whereas in SOX8, this domain is located in the central part of the protein. We have mapped SOX8 within 700 kb of the telomeric repeats of band 16p13.3. Hemizygosity for 1 Mb from this region causes the ATR-16 syndrome characterized by alpha-thalassemia and mental retardation. We show that SOX8 is deleted in an ATR-16 patient, and from its location, we deduce that it should be deleted in all previously described cases. Thus, SOX8 is a good candidate gene contributing to the mental retardation phenotype seen in ATR-16 patients.

Amino Acid Sequence↗
PubMed2000

Sudden death from trophoblastic embolism in pregnancy.

A case of a 24-year-old multigravida, with dry cough, dyspnea, fatigue, and weight loss with normal foetal growth rate is reviewed. Upon admission the patient suddenly became tachycardic, tachypnoic, cyanotic, followed by a non-palpable peripheral pulse, and asystole unresponsive to resuscitation. The autopsy revealed massive pulmonary trophoblastic embolism, bilateral pregnancy luteoma, and accelerated placental maturation. Trophoblastic embolism should be taken into consideration whenever cardiorespiratory emergency develops during pregnancy.

Adult↗
PubMed2000

Successful treatment of alloimmune thrombocytopenia using corticosteroid therapy in a woman with two consecutive neonatal deaths--case report.

Alloimmune thrombocytopenia is a serious fetal disorder resulting from platelet-antigen incompatibility between the mother and the fetus. In mild cases, the diagnosis is usually made upon detection of neonatal thrombocytopenia, but serious consequences such as fetal intracranial hemorrhage and/or unexplained fetal death may complicate the disorder. Various treatment modalities are suggested in the management of alloimmune thrombocytopenia, however, none has yet been confirmed as obviously superior. We report on the successful use of corticosteroids during pregnancy in a woman with a history of two consecutive neonatal deaths due to severe thrombocytopenia and HPA 5b platelet-specific antigen incompatibility.

Adult↗
PubMed1999

Campomelic dysplasia translocation breakpoints are scattered over 1 Mb proximal to SOX9: evidence for an extended control region.

Campomelic dysplasia (CD), a skeletal malformation syndrome with or without XY sex reversal, is usually caused by mutations within the SOX9 gene on distal 17q. Several CD translocation and inversion cases have been described with breakpoints outside the coding region, mapping to locations >130 kb proximal to SOX9. Such cases are generally less severely affected than cases with SOX9 coding-region mutations, as is borne out by three new translocation cases that we present. We have cloned the region extending 1.2 Mb upstream of the SOX9 gene in overlapping bacterial-artificial-chromosome and P1-artificial-chromosome clones and have established a restriction map with rare-cutter enzymes. With sequence-tagged-site-content mapping in somatic-cell hybrids, as well as with FISH, we have precisely mapped the breakpoints of the three new and of three previously described CD cases. The six CD breakpoints map to an interval that is 140-950 kb proximal to the SOX9 gene. With exon trapping, we could isolate five potential exons from the YAC 946E12 that spans the region, four of which could be placed in the contig in the vicinity of the breakpoints. They show the same transcriptional orientation, but only two have an open reading frame (ORF). We failed to detect expression of these fragments in several human and mouse cDNA libraries, as well as on northern blots. Genomic sequence totaling 1,063 kb from the SOX9 5'-flanking region was determined and was analyzed by the gene-prediction program GENSCAN and by a search of dbEST and other databases. No genes or transcripts could be identified. Together, these data suggest that the chromosomal rearrangements most likely remove one or more cis-regulatory elements from an extended SOX9 control region.

Adolescent↗
PubMed1999

Influence of hyperglycemia on early embryonal growth in IDDM pregnant women.

The association between maternal diabetes mellitus and congenital anomalies is well established. Congenital malformations in the offspring of diabetic mothers account for approximately forty percent of perinatal deaths. The aim of the study was to identify incidence of early embryonal delay in diabetic and normal pregnancies, and to examine relationship between the HbA1c values and early embryonal growth delay. One hundred twenty IDDM and fifty and four healthy women enrolled into the study. Pregnancy duration was confirmed by beta-HCG measurements within a fortnight from the missed menstrual period. No statistical difference was detected between the studied groups for gestational age, prepregnancy weight, newborns' birthweight and sex. The risk of spontaneous abortion in IDDM pregnancy with delayed embryonal growth was eight times higher than in IDDM pregnancies with normal growth pattern. No fetal malformations were determined in fetuses or newborns of either groups. The mean value and standard deviation of HbA1c in the IDDM patients with normal embryonic growth was 7.3 +/- 1.5%, and in the group of early embryonic growth, delay 9.39 +/- 2.37% respectively (F = 7.79; p = 0.006). This study confirmed the relationship between embryonal growth, spontaneous abortions and abnormal metabolic control of IDDM pregnancies.

Abortion, Spontaneous↗
PubMed1998

The SOX10/Sox10 gene from human and mouse: sequence, expression, and transactivation by the encoded HMG domain transcription factor.

The SOX genes form a gene family related by homology to the high-mobility group (HMG) box region of the testis-determining gene SRY. We have cloned and sequenced the SOX10 and Sox10 genes from human and mouse, respectively. Both genes encode proteins of 466 amino acids with 98% sequence identity. Significant expression of the 2.9-kb human SOX10 mRNA is observed in fetal brain and in adult brain, heart, small intestine and colon. Strong expression of Sox10 occurs throughout the peripheral nervous system during mouse embryonic development. SOX10 shows an overall amino acid sequence identity of 59% to SOX9. Like SOX9, SOX10 has a potent transcription activation domain at its C-terminus and is therefore likely to function as a transcription factor. Whereas SOX9 maps to 17q, a SOX10 cosmid has previously been mapped by us to the region 22q13.1. Mutations in SOX10 have recently been identified as one cause of Waardenburg-Hirschsprung disease in humans, while a Sox10 mutation underlies the mouse mutant Dom, a murine Hirschsprung model.

Adult↗
PubMed1998

Effects of preeclampsia and eclampsia on cord blood coagulation tests.

Blood coagulation tests were determined in fifty-three paired umbilical cord blood and maternal venous blood samples originating from term singleton vaginal cephalic deliveries. The index group comprised seventeen deliveries complicated by preeclampsia or eclampsia, and the control group comprised thirty-six healthy women with uneventful pregnancies and deliveries. Mean values obtained from the coagulation and fibrinolytic assays did not significantly differ between study groups, except for antithrombin III levels in index group of neonates, which were significantly lower. Comparison of coagulation and fibrinolytic characteristics between mothers and their neonates produced expected level of difference due to immaturity of their haemostatic mechanisms. We found alterations in maternal blood coagulation and fibrinolysis and evidence of increased intravascular coagulation with severe preeclampsia and IUGR.

Blood Coagulation Factors↗
PubMed1998

Ponderal index and disproportionate fetal growth in IDDM pregnancies.

Disproportionate macrosomia refers to excessive weight characterized by a high weight/length ratio. Disproportionate macrosomia is associated with an increased likelihood of neonatal complications. The aim of the study was to investigate incidence of ponderal indexes and disproportionate fetal growth rate in newborns originating from IDDM and healthy pregnancies. 144 IDDM pregnancies and 432 uneventful pregnancies with normal findings of oral glucose tolerance test were studied, and matched 1:3 for gestational age, sex of newborn, mothers's parity and year of delivery. The pregnancies selected terminated between 30-40th gestational week and resulted with live birth. Mean birth weight (+/- SD) in IDDM group was 3558 +/- 817.6 compared to 3132.4 +/- 534.4 grams of control group (F = 51.49; p < 0.001), mean birth length was 49.8 +/- 3.5 vrs 49.1 +/- 2.5 (F = 8.55; p < 0.005), mean gestation age by examination for both study groups 37.9 +/- 1.9, mean ponderal index of IDDM group was 2.82 +/- 0.28 vrs. 2.63 +/- 0.24 (F = 64.52; p < 0.001) of control group, rate of Apgar score < 7 was 21.14% vrs. 5.08% (chi 2 = 30.30; p < 0.001). 53.4% of IDDMs had macrosomia compared with 8.33% of control infants (chi 2 = 140.25; p < 0.001), and 35.24% of IDDMs had disproportionate macrosomia compared with 5.79% of control infants. Significantly higher rate of both proportionally and disproportionally grown infants with macrosomia was found among IDDMs than among control infants. The rate of disproportionate macrosomic infants significantly differ among study group.

Adolescent↗
PubMed1997

The effect of coagulation parameters on the placental respiratory and nutritive function in women having chronic hypertension with superimposed preeclampsia.

The aim of this study was to explore the relationship between coagulation and fibrinolytic system parameters with nutritive and respiratory placental function. We have analysed 79 pregnant women, of which 39 with severe preeclampsia (index group) and 41 healthy pregnant women. When comparing the study groups in third trimester, significantly lower platelet counts, fibrinogen values and antithrombin III values have been found in the index group compared to the control group. Factor VII levels were not found to be significantly different. The control group revealed significantly higher levels of coagulation factors II, V and VIII, compared to the index group. The increase of FDP, reduction of fibrinogen and increase of fibrinolysis in index group, when compared to the control group of healthy pregnant women, are the reflection of the intravascular fibrin deposition that leads to the described coagulation changes and consecutively to the foetal growth retardation. Indirect evidence are the correlation between newborns' weight and fibrinogen levels/fibrinolytic activity.

Adult↗
PubMed1997

Glycosylated hemoglobin and fetal growth in normal, gestational and insulin dependent diabetes mellitus pregnancies.

Aims of the study were: evaluation of HbA1c levels in the peripheral blood of pregnant women with insulin dependent diabetes, gestational diabetes, glucose intolerance, and healthy pregnant controls; implications of HbA1c concentration on detection and the control of women with impaired carbohydrate metabolism in pregnancy; comparison of HbA1c levels with appearance of miscarriages, and premature deliveries; comparison of weight gain during pregnancy to HbA1c levels; comparison of difference from ideal body weight with HbA1c in diabetic pregnant women; comparison of neonatal birth weight and HbA1c levels. 290 pregnant women were enrolled to the study. The highest value of HbA1c was in the group IDDM pregnant women (7.7% +/- 1.8%), and the lowest value of HbA1c was in the control group (4.1% +/- 0.5%). Statistically significant coefficients were found between HbA1c and weight gain during pregnancy, between weight deviation from ideal body weight and HbA1c (r = 0.54 and r = 0.48 respectively); and between newborns weight and HbA1c (r = 0.51). Well regulated glycemia and intensive pregnancy follow-up of diabetic women reduces stillbirths, neonatal complications and neonatal macrosomia incidence.

Adult↗
PubMed1995

YAC/P1 contigs defining the location of 56 microsatellite markers and several genes across a 3.4-cM interval on mouse chromosome 11.

The characterization of three YAC/P1 contigs from adjacent segments of the central region of mouse Chromosome (Chr) 11 is described. These contigs are based upon 63 YACs and 40 P1 recombinants. From these clones, 185 end sequences were obtained, of which 147 sequences could be converted into sequence-tagged sites and mapped within the three contigs. Deletions were detected in 16 out of 63 YACs; 19 of 63 YACs were found to be chimeric. No such aberrations were found in P1 recombinants. A total of 22 public and 34 newly developed microsatellite markers were unambiguously localized to and ordered in the contigs. In the cryb1/Nf1 interval of the central contig, several new genes have been identified by exon trapping and precisely localized with respect to known STS markers.

Amino Acid Sequence↗
PubMed1994

New member of the winged-helix protein family disrupted in mouse and rat nude mutations.

Mutations at the nude locus of mice and rats disrupt normal hair growth and thymus development, causing nude mice and rats to be immune-deficient. The mouse nude locus has been localized on chromosome 11 (refs 3, 4) within a region of < 1 megabase. Here we show that one of the genes from this critical region, designated whn, encodes a new member of the winged-helix domain family of transcription factors, and that it is disrupted on mouse nu and rat rnuN alleles. Mutant transcripts do not encode the characteristic DNA-binding domain, strongly suggesting that the whn gene is the nude gene. Mutations in winged-helix domain genes cause homeotic transformations in Drosophila and distort cell-fate decisions during vulval development in Caenorhabditis elegans. The whn gene is thus the first member of this class of genes to be implicated in a specific developmental defect in vertebrates.

Alleles↗