[Pernicious anemia and cancer risk].
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Anemia, Pernicious↗
Biomedical subjects
B Christensen
Publications and source records attributed to B Christensen.
Prenatal detection of chromosome aneuploidies by fluorescence in situ hybridization: experience with 2000 uncultured amniotic fluid samples in a prospective preclinical trial.
Successful rapid prenatal detection of selected numerical chromosome abnormalities by using fluorescence in situ hybridization (FISH) on uncultured amniotic fluid samples has been described by Klinger et al. (1992) and Ward et al. (1993, 1997). Using essentially the same FISH protocol and identical probes specific for chromosomes 21, 18, 13, X, and Y, we prospectively compared the results of FISH and conventional cytogenetics on 2000 amniotic fluid cell samples. The 1-day FISH assay yielded discrete differences in the signal profiles between cytogenetically disomic, i.e., normal, and trisomic samples. Due to intermittent absent Y-signals, the assay differentiated less well between samples with cytogenetically normal and abnormal sex chromosome complements. The assay efficiency, and thus the clinical utility, was affected by (1) unsuccessful hybridizations (7 per cent of all hybridizations), (2) hybridizations with less than 50 scorable nuclei (19 per cent of all hybridizations), and (3) visibly contaminated samples with possible maternal cell contamination (14 per cent of all samples). As a result, we were not able to reproduce the results of Klinger et al. (1992) and Ward et al. (1993, 1997).
Amniotic Fluid↗
Correlation of a common mutation in the methylenetetrahydrofolate reductase gene with plasma homocysteine in patients with premature coronary artery disease.
Mild hyperhomocysteinemia, a risk factor for occlusive arterial disease, can be caused by disruptions of homocysteine metabolism. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the synthesis of 5-methyltetrahydrofolate, the methyl donor for homocysteine remethylation to methionine. A common mutation in MTHFR, an alanine-to-valine substitution, may contribute to mild hyperhomocysteinemia in coronary artery disease (CAD). To test this hypothesis, we studied 152 patients with CAD by mutation analysis, MTHFR enzymatic assays, and measurements of plasma homocysteine and several vitamins. The MTHFR mutation was associated with reduced enzymatic activity and increased enzyme thermo-lability in these patients. The difference in the prevalence of the homozygous mutant genotype between the CAD patients (14%) and an unmatched group of healthy subjects (10%) was not significant. However, individuals with the homozygous mutant genotype had higher plasma homocysteine, particularly when plasma folate was below the median value. This genetic-environmental interaction is proposed to be a risk factor for CAD.
Adult↗
Hearing instruments and health technology--an evaluation.
This contribution compares a currently worn hearing instrument (i.e. R-HI) with a programmable multiband full-dynamic range compression behind-the-ear HI (i.e. T-HI), based on subject preference for HI, and, in addition, compares the preference for a linear/ non-linear amplification-mode (i.e. L-mode/C-mode). Finally, it evaluates some health technology aspects related to the devices. N = 34 experienced HI-users at a median age of 72 years (range 22-84) completed the trial, n = 5 being monaurally, and n = 29 being binaurally fitted. The trial comprises an unblinded comparative study of the R-HI and T-HI, in either C-mode or L-mode amplification, and a double-blind crossover study evaluating the C-mode versus the L-mode amplification. The results of the unblinded study showed that 94% (n = 32/34) preferred the T-HI, whereas two subjects preferred their current HI. The double-blind crossover study concerning the preference for the C-mode and L-mode, respectively, in the T-HI, showed that 72% (n = 23/32) had a significant preference for the non-linear amplification, whereas 28% (n = 9/32) preferred the linear amplification. Provided that the price of the T-HI is kept unchanged, a health technology evaluation may imply an estimate of 30 mill. DKR added costs on a national basis, which should be taken into account within the national hearing services.
Adult↗
The Valby Project: a survey of hearing in the elderly > or = 80 years of age not provided with hearing aids.
This contribution forms part of an epidemiological study of hearing in the elderly > or = 80 years of age, living in an urban area. The study concentrates on the prevalence of self-reported hearing problems in a sample of subjects not provided with hearing aids (HAs), hearing level, and knowledge of and attitudes to HAs. Among the total population of 2915 > or = 80 years of age, an age- and sex-matched sample of 565 subjects was invited to attend an extensive audiological evaluation, including a questionnaire, giving information on knowledge about and attitudes to HAs. Forty-one percent (n = 231) attended, and dividing the attenders into 5 or 10 year age bands showed that the better and worse ear hearing levels, averaged across 0.5-4 kHz (BEHL/ WEHL0.5-4 kHz), deteriorate significantly with increasing age, and that no differences as a function of gender could be found. The prevalence of self-reported hearing problems was 44% (n = 101), and among these 30% (n = 30) indicated the potential need for a HA. A significantly poorer BEHL0.5-4 kHz was found in these subjects compared to those without hearing problems and/or need of a HA. In the total sample, 63% reported that a HA can ameliorate a hearing problem; however, 62% indicated that the HA should be invisible, and 28% that a HA 'makes you old'.
Age Factors↗
Hearing in the elderly > or = 80 years of age. Prevalence of problems and sensitivity.
This article is part of an epidemiological study on hearing in an urban population > or = 80 years of age, and concentrates on the prevalence of hearing problems and hearing sensitivity as a function of age and gender. Prior to the study, 2915 residents aged 80+ from the Valby area in Copenhagen were selected for investigation and subdivided into two groups. The first group, comprising n = 859 subjects previously provided with HA, and the second group, resulting from an invitation mailed to n = 565 subjects, were matched according to the age and gender distribution of the population, i.e. 24% males and 76% females. Among these, only 41% at a median age of 84 years, range 80-96, accepted the invitation, being significantly younger than the non-attenders. The estimated prevalence of self, reported hearing problems ranged between 33 and 66%, increasing with increasing age. Significant differences were found in the hearing sensitivity as a function of gender, i.e. the hearing in the low-frequency area < 1 kHz is better, whereas the hearing sensitivity at > 2 kHz is significantly worse in males compared with females. The speech recognition score (SRS) was significantly higher in females compared with males, and a comparison between ears supports the finding that the right ear speech recognition score is better than the left. The study demonstrates the difficulties in obtaining reliable epidemiological data on the hearing in the elderly > or = 80 years, which represents an obstacle for the planning of appropriate hearing health services directed towards this age group, and collaborative studies are suggested in order to accumulate more knowledge.
Aged↗
[Differential diagnosis of cystic adnexa processes. A comparison of the value of sonography, puncture cytology and color and biochemical biopsy analysis with histology].
The histological diagnoses of 109 cystic adnexal masses were compared with the results of ultrasound examination, color, cytology and biochemical analyses of cystic fluid. In cases with suspicious results by ultrasound examination most of the malignant tumors but only a small number of benign cystic masses were found. Macroscopic and cytologic examinations gave no further informations. By biochemical analyses functional cysts could be detected with 86% of sensitivity and 100% of specificity by a combination of estradiol, progesterone and Ca 12-5. Endometrioma and malignant tumors could be separated from other adnexal masses (specificity 95%, sensitivity 100%) with a combination of Tag 72-4 and CASA.
Adenofibroma↗
[Luteal defect in pregnancy as the cause of habitual abortion].
About 15 of all women in the reproductive age are involved by recurrent abortions. The pathophysiology is different; chromosomal, infectious, immunologic and endocrine reasons and anomalities of the uterine cave are discussed. Though there is a discrepancy between the regular secretory phase needed for implantation and low progestins in early pregnancy inducing abortion, the theory of recurrent abortions induced by ovarian malfunction is critically discussed in literature. Basing on the knowledge of the regulation of ovarian function and a delayed pregnancy without ovarian function in early pregnancy in a patient with recurrent abortions, a defect of the corpus luteum-rescue is the most probable explanation. This defect characterized by regular beta-HCG- and pathological decreased progestin and estradiol levels should be treated by substitution of progestin and estradiol. Though a defect of the HCG-receptor is possible a HCG-substitution seems to be an inadequate therapy.
Abortion, Habitual↗
Induction of blister-causing antibodies by a recombinant full-length, but not the extracellular, domain of the pemphigus vulgaris antigen (desmoglein 3).
Pemphigus vulgaris (PV) is mediated by autoantibodies to desmoglein 3, the pemphigus vulgaris antigen (PVA). PVA and an extracellular domain of PVA-Ig fusion protein (PV-Ig) can completely adsorb the blister-causing Abs from PV patient sera, suggesting that the extracellular segment of PVA might be sufficient to induce pathogenic Abs. To test this, we immunized rabbits with either PVA or its extracellular domain (EPVA) expressed in insect cells in our laboratory. When Igs were passively transferred from these rabbits into neonatal mice, anti-PVA, but not the anti-EPVA, induced blisters. To understand the basis for their differential pathogenic effects, we examined the properties of these sera. Both sera showed comparable ELISA titers and indirect immunofluorescence reactivity against monkey esophagus, a source of native PVA. Moreover, EPVA, like PVA adsorbed blister-causing Abs from sera of PV patients and rabbits immunized with PVA. In contrast, when IgG preparations were incubated with fura-2-AM (acetyloxymethyl ester)-loaded human keratinocytes in culture, only IgG from anti-PVA serum induced intracellular calcium mobilization. These data showed that PVA but not EPVA can elicit Abs that induced blisters in neonatal mice and mediate intracellular signaling through calcium mobilization.
Amino Acid Sequence↗
[Prevention in family practice].
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Denmark↗
[Folate deficiency, cancer and congenital abnormalities. Is there a connection?].
The biochemical role of folate is in the interconversion of one-carbon units in intermediary metabolism; a process in which a methyl group is formed de novo. The methyl group is subsequently transferred to adenosylmethionine, which is an important methyl donor in the methylation of DNA. A negative correlation exists between the intake of folate in pregnancy and the occurrence of neural tube defects and certain malignant brain tumours in children. Numerous clinical studies have pointed to an association between folate status in adults and both the occurrence of cancer and the premalignant changes, cervical dysplasia, bronchial metaplasia, and colorectal adenomas. Folate deficiency may cause chromosomal damage, due to impaired DNA synthesis or repair. Moreover, decreased production of adenosylmethionine may influence the expression of developmental genes and of oncogenes and/or tumour suppressor genes through disturbed methylation of DNA.
Adult↗
Simplicity-correlated size growth of the nuclear 28S ribosomal RNA D3 expansion segment in the crustacean order Isopoda.
The expansion segments within the eukaryote nuclear 23S-like ribosomal RNA molecule are now well characterized in many diverse organisms. A different base compositional bias, a higher propensity for size variability, and an increased evolutionary rate distinguish these regions from the universally conserved "core" regions of the molecule. In addition, some expansion segments of higher eukaryotes exhibit significant sequence simplicity which is hypothesized to occur by slippage-mediated mutational processes. We describe the discovery of extreme size variation of the D3 expansion segment in the crustacean order Isopoda. Among 11 species D3 varies in size from 180 to 518 nucleotides but maintains a homologous secondary structure. The D3 size is significantly positively correlated to relative simplicity factor (RSF), indicating that growth is most likely by insertion of simple sequences. D3 size and RSF correlate approximately with a morphology-based phylogeny, and within oniscideans RSF increases as more recent divergences occur. The D3 of Armadillidium vulgare, with an RSF of 1.87, is the highest value recorded for any known expansion segment. Regions of high sequence simplicity in nuclear ribosomal RNA were previously only known from the higher vertebrate lineage. Here we demonstrate that this phenomenon occurs in a more extreme condition within a monophyletic invertebrate lineage. The extreme size changes identified could indicate that expansion segments are an extraneous element in the functioning ribosome.
Animals↗
Epidemiology of permanent hearing impairment in children in relation to costs of a hearing health surveillance program.
The objective of this investigation was to estimate the prevalence of any permanent hearing impairment (PHI) in the right and or left ear based on children included into a surveillance program in the local pediatric hearing health services (PHHS), and to analyze the costs, generated by the children. The study is a cross-sectional study, which is part of a major prospective study directed towards delineation of all aspects of pediatric audiology. The present sample comprises 228 children, 115 males and 113 females, at a median age of 13 years, range 0-24, and involves all children living in the health district of the City of Copenhagen, who are or have been included in a local surveillance program with one (school children) or two (pre-school children) annual visits for children with PHI > 20 dB HL at any frequency in either the left or the right ear. The prevalence of PHI increases with increasing age, reaching its peak in the age band 10-14 years exhibiting a rate of 5.32 1000 (95% confidence intervals: 4.27 to 6.64 per 1000). The estimated incidence of PHI in a ten year cohort born 1977-1986 is 325 100 000 children born (95% confidence intervals: 277 to 382 per 100 000). The most frequent factor causing PHI is inheritance, showing an increase from 20% in 1977-1981 cohorts, to 37% in 1982-1986 cohorts. The costs involved in the PHHS concerning PHI varies considerably from approximately 345 000 to 990 000 DKr.. depending on the model used for the economical analysis. No data on cost-benefit or cost-effectiveness can be given in this context, and it is concluded that the documented changes in the prevalence and causes of PHI in children emphasize the need for a continuous monitoring and evaluation of the epidemiological figures.
Adolescent↗
[The so-called "chocolate cyst"--frequently misinterpreted as ovarian endometriosis?].
Limitation of morphological diagnostic and possible misinterpretations are shown in a patient with anamnestic ovarian endometriosis. In cases of "chocolate cysts" it is necessary to differentiate between ovarian endometriosis and functional cysts. Hints for the existence of a functional cyst are an atypical past history or perioperative findings. Biochemical analysis of the cyst fluid may lead to a correct diagnosis.
Adult↗
Human methionine synthase: cDNA cloning and identification of mutations in patients of the cblG complementation group of folate/cobalamin disorders.
Methionine synthase catalyzes the remethylation of homocysteine to methionine in a methylcobalamin-dependent reaction. We used specific regions of homology within the methionine synthase sequences of several lower organisms to clone a human methionine synthase cDNA by a combination of RT-PCR and inverse PCR. The enzyme is 1265 amino acids in length and contains the seven residue structure-based sequence fingerprint identified for cobalamin-containing enzymes. The gene was localized to chromosome 1q43 by the FISH technique. We have identified one missense mutation and a 3 bp deletion in patients of the cblG complementation group of inherited homocysteine/folate disorders by SSCP and sequence analysis, as well as an amino acid substitution present in high frequency in the general population. We discuss the possibility that a mild deficiency of methionine synthase activity could be associated with mild hyperhomocysteinemia, a risk factor for cardiovascular disease and possibly neural tube defects.
5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
The Valby Project. A survey of the hearing in the elderly > or = 80 years of age-provided with hearing aids.
This contribution forms part of an epidemiological study of the hearing in the elderly > or = 80 years of age and describes some of the rehabilitative aspects. The sample is defined according to an age > or = 80 years of age, living in the Valby district at the time of data collection (November 1993), and provided with a hearing aid (HA) during this period 1988-1993. All information in this part of the survey is obtained from the records in the Department. The overall prevalence of HA provision was 30% (n = 859/2915) with no differences as a function of gender. The prevalence of HA provision indicated an increase from 20% at the age of 80-84 to 61% at an age of > or = 95 years of age. Among the sample, 42% were first-time applicants, whereas 58% were experienced users. The better and worse ear hearing level, averaged across 0.5-4 kHz, showed significantly poorer hearing in the experienced users compared to the inexperienced users; however, there were no significant differences as a function of 5-year age bands. In the inexperienced users a moderate hearing loss of 43-49 dB was found in the better ear hearing, averaged across 0.5-4 kHz. The average across 4-8 kHz showed significantly poorer hearing in males compared to females, which is compatible with the poorer speech recognition score in background noise (S/N = 10 dB) (SRSN) in males. An immediate benefit of HA provision was found in these elderly subjects, the majority obtained a benefit of 12-32%, measured by SRSN. It is concluded that the prevalence of 30% of HA provision is incompatible with the high prevalence of about 50% of hearing problems, indicated at the defined age, and that additional epidemiological data are needed.
Aged↗
Primary physicians and the elderly hearing-impaired. Actions and attitudes.
This study was undertaken in the Valby health district in Copenhagen in order to evaluate the activities and attitudes of GPs concerning hearing problems in their elderly patients. Among 55 GPs offering health services to the 2915 residents > or = 80 years of age in the district, 76% (n = 42) responded to a structured questionnaire or personal interview, evaluating their line of action concerning hearing problems, and their knowledge and attitudes towards hearing aids (HAs). Among the responding GPs, 7% always seek information on the hearing ability of their elderly patients at the defined age, whereas 14% never focus on the hearing; 45% of the GPs always refer to an ENT specialist when hearing problems are present, which causes further delay in the rehabilitation process and increases costs within the primary health care sector. GPs' attitudes to HAs seem to be changing in a positive way, 91% of them revealing a positive attitude to HAs, and 86% indicating that a HA is capable of ameliorating a hearing problem in the elderly. Irrespective of this positive attitude, the knowledge of types of HAs among GPs seems limited. The study cannot support the idea of making HAs prescribable by GPs unless they are first offered intensive courses on audiology.
Aged↗
Partial reconstitution of the respiratory burst oxidase in lymphoblastoid B cell lines lacking p67-phox after transfection with an expression vector containing wild-type and mutant p67 -phox cDNAs: Deletions of the carboxy and amino terminal residues of p67-phox are not required for activity.
The respiratory burst oxidase of phagocytes and B lymphocytes in a multicomponent enzyme that catalyzes the reduction of oxygen by NADPH. It is responsible for O-(2) production in response to stimulation with phorbol 12-myristate 13-acetate (PMA). The study of patients with chronic granulomatous disease (CGD), an inherited disorder characterized by deficient of absent respiratory burst activity, has contributed greatly to our understanding of the NADPH-oxidase. The absence of any one of four components results in the clinical expression of CGD: the two membrane-bound components of the cytochrome b-558, gp91-phox and p22-phox, or the cytosolic factors, p47-phox and p67-phox. We used a system to investigate the activity of mutant p67-phox proteins expressed in a reconstitution assay. This system is characterized by the partial reconstitution of O-(2) production in an Epstein-Barr virus (EBV)-transformed lymphoblastoid B cell line from a patient with p67-phox-deficient CGD by transfection with an expression plasmid containing the 67-phox cDNA in the sense orientation. No O-(2) production was detectable in p67-phox-deficient lymphoblastoid B cell lines transfected with an antisense plasmid or in untransfected p67-phox lymphoblastoid cells stimulated by PMA. We tested two mutants, pEBOp67delta1-22 and pEBOp67delta512-526, and found that both recombinant proteins are active in our system. Thus, we conclude that the first 22 amino acid residues and the last 14 amino acid residues are not critical for initiation of O-(2) production
B-Lymphocytes↗