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Biomedical subjects

B Christensen

Publications and source records attributed to B Christensen.

At least 217 records · Page 12Linked to original sources
PubMed1979

Plasma lipids, lipoproteins, and blood pressure in female adolescents using oral contraceptives.

Comparative profiles are reported for plasma lipids and lipoproteins, blood pressure, smoking, and selected socioeconomic variables for females less than 20 years of age using oral contraceptives and for pair-matched non-users from the Lipid Research Clinics Prevalence Study. About 5% of adolescent females reported OC use; they had significantly higher levels of plasma total cholesterol, triglyceride, and high-density lipoprotein-cholesterol than did the non-users. Significantly more non-users of OC belonged to households of the lowest occupational status; no differences in OC usage by educational status of the head of household were discernible. Of the OC users, 58% were classified as current smokers, as compared with 23% of the non-OC users.

Adolescent↗
PubMed1978

Sympathetic innervation of the urinary bladder and urethral muscle in the pig.

The sympathetic innervation of the lower urinary tract was studied in the female and male pig using a specific histochemical technique for visualization of noradrenaline containing nerves. In smooth muscle from the detrusor few evenly distributed adrenergic nerve terminals were found. A greater number of terminals were observed in the trigone, bladder neck and urethra. There was no sex difference. In smooth muscle specimens from pig detrusor and trigone sympathetic nerve terminals were more abundant than in corresponding tissue from humans.

Animals↗
PubMed1978

Human sympathetic bladder innervation. A morphological investigation.

A method for histochemical determination of noradrenergic nerve fibers in human bladder biopsies is described. The importance of an objective criterium for distinguishing between specific noradrenaline fluorescence and autofluorescence of connective tissue is stressed. In 2 females and 3 males without neurogenic bladder disease the noradrenergic innervation of the detrusor as well as the trigonal muscle was found very scarce.

Animals↗
PubMedDate not supplied

Latex agglutination detection of group-B streptococcal inoculum in urine.

It is not uncommon for a newborn to be blood culture negative, but urine latex particle agglutination (LPA) positive for group-B streptococcus (GBS). We hypothesized that whole-cell GBS contamination of urine, which is possible in bag-collected specimens, could cause LPA positivity. Serial tenfold dilutions through 10(-8) of an 18-hr broth suspension of GBS serotype III were prepared in sterile urine. Directigen (Becton-Dickenson Microbiologic Systems, Cockeyville, MD) LPA testing was performed on each sample at inoculation and, if negative, every 2 hr until becoming LPA positive. All tubes were quantitiatively cultured when becoming LPA positive. The assay was performed four times to evaluate independently the effects of urine sample centrifugation, volume, glucose content, and incubation temperature. An 18-hr GBS suspension dilution of 1:10,000 in urine and as few as 5.7 x 10(3) organisms/ml caused LPA positivity at time 0. Urine supported sufficient replication to enable log 0 concentrations (10(-8) dilution) to become LPA positive within 8 hr at 35 degrees C, a routine infant incubator setting. Alteration by centrifugation, volume, or glucose content had no effect on LPA positivity or time needed to become positive. We conclude that Directigen LPA can detect a relatively small concentration of GBS organisms in urine. Due to potential contamination from skin bacteria, positive LPA results from bag urine should be interpreted with caution in the absence of positive cultures.

Bacteriuria↗
PubMedDate not supplied

Studies on the isolation and identification of fetal nucleated red blood cells in the circulation of pregnant women before and after chorion villus sampling.

OBJECTIVE: To investigate the feasibility of various molecular forms of hemoglobin as markers for fetal nucleated red blood cells (NRBCs). METHODS: The presence of epsilon and gamma globin positive NRBCs was investigated in pure fetal blood and in blood from pregnant women before and after chorion biopsy. Maternal samples were enriched for NRBCs by various conventional methods, including limited enrichment by only positive CD71 selection or single density gradient. We searched for fetal cells on slides by automated scanning. Fetal cells were defined by (1) the presence of epsilon or gamma globin and (2) simultaneously by the presence of a Y chromosome signal. RESULTS: 18 of 25 gamma globin positive cells identified in blood samples after chorion biopsy were chromosome Y signal positive, and 1 cell had two X chromosome signals. 263 of 339 epsilon globin positive cells identified in blood samples after chorion biopsy were hybridized with X and Y chromosome probes. None had two X signals, and 249 were Y positive. In blood samples before chorion biopsy, only 1 epsilon globin positive fetal NRBC and no epsilon globin positive maternal NRBCs were found. CONCLUSIONS: Epsilon globin may be specific for fetal NRBCs. Only 1 epsilon globin positive fetal cell was identified in 1 of 12 blood samples before chorion biopsy, representing a total of 182 ml of maternal blood. This suggests that most fetal cells found in maternal blood by fluorescence in situ hybridization methods may not be NRBCs.

Antibody Specificity↗
PubMedDate not supplied

Prenatal diagnosis by fluorescence in situ hybridization on chorionic villus cells: nonsignificance of maternal cell contamination.

We assessed the effect of maternal cell contamination on the sensitivity of prenatal diagnosis by fluorescence in situ hybridization (FISH) on overnight attached mesenchymal chorionic villus cells. Double targets FISHs with X and Y chromosome-specific probes were performed on parallel samples from the same pregnancies: (1) samples of assumed fetal tissue retained during dissection, and (2) samples of suspected maternal tissue discarded during dissection. In the karyotypically male samples the tissue retained during dissection contained 0-3% nuclei with two X-specific signals each. In the tissue discarded from the karyotypically male samples 0-50% of the nuclei had two X-specific signals each. We conclude that given thorough dissection of chorionic villi, the sensitivity of prenatal diagnosis of aneuploidies by FISH on overnight attached samples of this tissue is not critically affected by maternal cell contamination.

Chorionic Villi Sampling↗
PubMedDate not supplied

Light and scanning electron microscopy of nasal biopsy material from patients with naturally acquired common colds.

As our knowledge of the histopathology of common colds is very limited, we have undertaken a blind quantitative examination by scanning electron microscopy and light microscopy of 56 nasal biopsies, taken from 29 volunteers with naturally acquired colds. In agreement with earlier reports we found evidence of sloughing of epithelial cells, but in contrast to in vitro experiments, this did not result in a destruction of the epithelial lining, which by and large remained continuous, with structurally normal cell borders. There was a significant increase in the number of neutrophils, both in epithelium and in lamina propria, already on the 2nd day of the disease, and the hypothesis is advanced that the virus infection itself is the cause of the local neutrophilia. The only other abnormality demonstrated was an increased number of extracellular erythrocytes in the acute stage. The histological picture was not suggestive of an involvement of epithelial mast cells in the inflammation.

Adult↗
PubMedDate not supplied

Inherited sensorineural low-frequency hearing impairment: some aspects of phenotype and epidemiology.

This contribution forms part of the HEAR project. It describes some phenotypes of inherited low-frequency sensorineural hearing impairment (LFSHI) and estimates the prevalence of this inherited hearing impairment (HI) based on a clinical series. During a 10-year period (1987-1996), 418 subjects (134 males and 284 females), with a median age of 68 years (range 4-98), had been examined with LFSHI, defined as hearing loss most pronounced in the low frequencies (i.e., 250 and 500 Hz > 20 dB HL with better hearing, i.e., > or =15-dB difference at 1 and/or 2 and/or 4 kHz with an air-bone gap <15 dB for the average of 0.5, 1, and 2 kHz). The 418 subjects comprising 0.6 per cent of the total number of subjects examined (N=69,309) were subdivided into four categories: category I positive genetic subjects (N=69); category II, probably genetic (N=339); category III, uncertain genetic (N=6); and category IV, subjects with contradictory audiological findings (N=4). The phenotype in category I demonstrated a symmetrical LFSHI, with a pattern of progression showing a slow deterioration in the high frequencies (i.e., 2, 4, and 8 kHz as a function of age)--the progression comprising 40-45 dB. In the low frequencies (i.e., 250, 500, and 1,000 Hz), a deterioration of 15-25 dB could be demonstrated from the youngest to the oldest age group. In category II, a symmetrical LFSHI was found in 179 subjects, showing the same pattern of progression as in category I. However, in the age group 20-39 years, a significantly poorer hearing was found in the low frequencies compared to category I, implying that several phenotypes may be present in LFSHI. A subgroup (A) in category II exhibited normal hearing in one ear with LFSHI in the opposite ear with the same pattern of progression as in category I. Three other subgroups with LFSHI and flat/sloping audiogram in the opposite ear and asymmetrical LFSHI also showed the same type of progression in the ear with LFSHI as in category I. A prevalence of 0.18/1,000 (95 per cent CI 0.13-0.22) of LFSHI was estimated based on the background population with a fairly constant prevalence throughout life. It is concluded that inherited nonsyndromal LFSHI is a rare disease and that the many different phenotypes of LFSHI probably are associated with pronounced genetic heterogeneity.

Acoustic Impedance Tests↗
PubMedDate not supplied

A double-blind cross-over study of a non-linear hearing aid.

New hearing aids are usually introduced after clinical trials. These are mostly based on subjects reports, in which it is possible that the subject's judgment of the acoustic performance might be influenced by the awareness that it is a new hearing aid which is being investigated. To examine the benefit of a new non-linear amplification circuit, a double-blind cross-over study was conducted. Two 'new' hearing aids were developed; they were identical in external appearance and differed only in that one involved ordinary linear amplification while the other employed compressive amplification (the K-amp circuit). Forty-five experienced users with sensorineural hearing loss, aged 60-80 years, used each of the aids for ten weeks, in balanced order. The subjects' need for hearing aid ranged from listening to radio and television to extensive use in all kinds of demanding listening situations. The results, using a structured questionnaire concerning real-life settings, speech reception tests and subject preferences for a particular hearing aid, showed little difference between the two hearing aids. Twenty-three subjects selected the non-linear amplification circuit, 20 subjects preferred the linear hearing aid and two chose to return to their previous aid. No consistent differences between those preferring the linear circuit and those preferring compression were found. It can be concluded that this compression amplification circuit is not significantly preferred to the traditional linear hearing aid.

Aged↗
PubMedDate not supplied

Some experiences with hearing disability/handicap and quality of life measures.

To achieve detailed information on the outcome of hearing rehabilitation in a clinical setting, measurements of hearing disability and hearing handicap have been introduced, and the present study describes the preliminary experiences with these measures in a series of hearing-impaired subjects referred for audiological evaluation. To outline hearing disability/hearing handicap (HD/HH), before continuation or initiation of treatment, the Gothenburg profile and a generic health-related quality of life--the SF-36 questionnaire--were used to evaluate any adverse effects resulting from hearing disorders. The Gothenburg profile and the SF-36 questionnaire were mailed to 634 subjects appointed for audiological examination with a request to complete the questionnaires at home. Three questions were enclosed concerning the capacity to complete the questionnaires, showing that 1.9 per cent were incapable of completing them, 17.5 per cent needed assistance, 43.5 per cent completed the questionnaires, and 37.1 per cent did not respond to them. Thus the response rate was only 55.5 per cent and, in addition, these responses were characterised by missing data. An arbitrary criterion of an average score per question of >3 for the averaged HD and HH items respectively was applied, resulting in 72.7 per cent indicating HD, whereas 30.3 per cent indicated HH according to the items in the profile. Significant differences in hearing levels were found between those experiencing HD and HH having a score >3 and those with a score <3. When analysing the general health status, general perception of health and social functioning, significantly lower scores were found for those experiencing HD/HH, whereas no significant differences were found between the total sample of hearing-impaired subjects and the age-matched population for these parameters. It is concluded that the present procedure cannot be implemented as a routine outcome measure in a clinical setting and alternative outcome measures should be considered.

Adult↗
PubMedDate not supplied

In vitro studies of human bladder cancer.

Explantation and cultivation in vitro of 55 human biopsies of histologically normal urothelial tissue, and 63 biopsies from transitional cell carcinomas (TCC) revealed a primary success rate of about 75% and a secondary success rate of about 50% with no significant differences, between normal and TCC derived cultures. While only half of the subcultured biopsies of normal origin were able to grow for more than 4 passages all TCC derived cultures were able to do so. Based on morphology, life span, invasive growth into co-cultured fragments of embryonic chick heart, and tumorigenicity in nude mice the following transformation grades (TGr) were defined: Normal (TGr 0), non-malignant with prolonged, but finite life span (TGr I), premalignant with infinite life span but without tumorigenic and invasive potential (TGr II), malignant with infinite life span and tumorigenic and invasive properties (TGr III). Differentiation between TGr I - TGr III was possible by several other parameters, including cytological characteristics, molecular and immunological surface structure, relative oncogene expression, pyruvate kinase isoenzymes, DNA Repair, and growth pattern. However, in addition to these common characteristics, the individual cell lines of the various categories of transformation showed differences that allowed the identification of well defined cell lines and sublines.

Animals↗