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Biomedical subjects

J Nielsen

Publications and source records attributed to J Nielsen.

At least 415 records · Page 23Linked to original sources
PubMed1984

Chromosome abnormalities and season of birth.

A study of seasonality has been made of birth of individuals with chromosome abnormalities registered in the Danish Cytogenetic Central Register before January 1, 1981. Significant seasonal variation in birth was found for males with Klinefelter's syndrome born before 1946, but not for those born later, and not for any other sex chromosome abnormality. No significant monthly variation was found for any autosomal abnormality, except a significant increase in the frequency of conceptions for Down's syndrome during the first 4 months of the year, using a chi square with 2 degrees of freedom.

Chromosome Aberrations↗
PubMed1984

The promoters of the atp operon of Escherichia coli K12.

The nucleotide sequence has been determined of a 900 bp segment of chromosomal DNA located between 2.6 and 3.5 kb left of the origin of replication, oriC. This segment, which overlaps with the known sequence of the atp operon coding for the eight subunits of the Escherichia coli K12 ATP synthase, contains two coding sequences with the same polarity (counterclockwise) as the atp genes: One of these, designated atpI, which codes for the N-terminal part of a 14 kD polypeptide, is located in front (upstream) of the atpB gene (the first structural gene in the atp operon), the other one codes for the C-terminal part of the gidB gene. The 606 bp segment located between the gidB and the atpI genes contains no coding sequences. By employing the nuclease S1 mapping technique, we have determined a promoter, designated atpIp, for the atp operon located in front of the atpI gene; two additional, weak transcription starts were located within the atpI gene. No transcription start sites were detected up to 1,000 bp upstream of the atpIp promoter, neither were any transcription start sites detected within the cluster of the eight structural atp genes. The atp operon transcription terminates at a site approximately 50 bp downstream from the atpC gene.

Amino Acid Sequence↗
PubMed1984

The impact of large Y chromosome on pregnancy, foetus and birth.

In a current investigation of children born in the Arhus area (Denmark) chromosome examinations were made in 6,691 newborns. Of these children, 170 boys had a large Y chromosome (2.6%). The present material was examined using a bi-variate stratified analysis to eliminate social and simple biological factors that could act as confounders. No increased frequency of malformations was found, and birth weight and length was nearly equal in the probands and the controls. A significantly increased frequency of prostaglandin stimulation of labour was found for the mothers of the Yq+ boys. Differences in the frequency of mechanical disproportion or abnormal presentation could not explain this. The Yq+ boys suffered more frequently from intrauterine asphyxia leading to acute Caesarean section. This finding cannot be explained by long-standing placenta problems alone. A possible mechanism which could link these findings together is suggested, and it is concluded that the boys with Yq+ most probably should be regarded as being at a certain risk at the time of birth.

Apgar Score↗
PubMed1984

Diagnosing of chromosome abnormalities in Denmark.

A survey of how frequent chromosome abnormalities are diagnosed in Denmark prenatally as well as postnatally compared with the expected incidence in an 11-year period 1970-1980 has been made from the Danish Cytogenetic Central Register. Ten percent of the expected number of Klinefelter's syndrome, 41% of Turner's syndrome and 10% of other sex chromosome abnormalities in children born between 1970 and 1980 have been diagnosed until January 1, 1983. The total frequency of diagnosed cases with sex chromosome abnormalities is 13% of the expected number. Induced abortion was made in 62% of the cases with sex chromosome abnormalities diagnosed prenatally. Ninety percent of all cases with Down's syndrome were diagnosed by chromosome examination, and 10% were diagnosed prenatally and aborted. During the last part of the period from 1977-1980 this had increased to 20%. Thirty-seven percent of cases with other chromosome abnormalities were diagnosed. Among the expected 4,396 children with chromosome abnormalities to be born between 1970 and 1980, a total of 39% were diagnosed postnatally until January 1, 1983, and 10% were diagnosed prenatally. It is concluded that there is a great need for training consultants in clinical genetics, expansion and further decentralization of cytogenetic service with more cytogenetic laboratories and employment of clinical geneticists in all 14 Danish counties.

Chromosome Aberrations↗
PubMed1984

Non-painful phantom limb phenomena in amputees: incidence, clinical characteristics and temporal course.

58 patients undergoing limb amputation mainly because of peripheral vascular disease were interviewed by means of a standard questionnaire and examined 8 days, 6 months and 2 years after limb amputation regarding non-painful phantom limb phenomena. During the follow-up period, 41% of patients died. The incidence of phantom limb 8 days, 6 months and 2 years after limb loss was 84%, 90% and 71%, respectively. Phantom limb phenomena changed within the first half year after amputation from a mainly proximal and distal distribution to a mainly distal localized sensation. While approximately 3/4 of patients with phantom limb had kinaesthetic sensations in the limb (i.e. feeling of length, volume or other spatial sensation) during the first 6 months after amputation, less than 50% of patients had this later in the course; 30% of patients noticed a clear shortening of the phantom limb during the follow-up period. While the incidence of phantom limb did not decrease during the follow-up period, both the duration and frequency of phantom limb phenomena declined significantly. The distribution of non-painful and painful phantom limb did not differ significantly from each other. The present findings suggest that mechanisms both in periphery, spinal cord and brain participate in generating the phantom limb percept.

Adult↗
PubMed1984

Modification of the bone marrow toxicity of cis-diamminedichloroplatinum(II) in mice by diethyldithiocarbamate.

It has been shown that cis-platinum-induced nephrotoxicity in rats can be inhibited by diethyldithiocarbamate (DDC). We report here the bone marrow protective properties of DDC in hybrid (C57BL X BALB/c) mice exposed to single and fractionated doses of cis-platinum. Relatively nontoxic doses of DDC afford maximum protection, using that dose of cis-platinum that would result in the death of 50% of the mice within 9 days as an end point (dose-limiting gut toxicity in mice), when injected 0.5 to 2 hr following i.p. cis-platinum treatment. Survivals of colony-forming units in spleen, nucleated bone marrow cells, and peripheral white blood cell were used to assess the bone marrow protective properties of DDC following both single and fractionated doses of cis-platinum. A dose modification factor of 3.2 (based on colony-forming units in spleen survival) was obtained when DDC (1000 mg/kg) was injected into mice 0.5 hr after graded doses of cis-platinum. When fractionated doses of cis-platinum were used (6 mg/kg on Days 0, 10, 20, and 30), the survival of colony-forming units in spleen was markedly enhanced if the animals were rescued with DDC 0.5 hr following each cis-platinum dose. When bone marrow cellularity was measured immediately before and 2 days after each dose of cis-platinum, a similar pattern of depression and recovery was noted whether DDC was present or not; however, the depression was less marked in mice rescued with DDC. When peripheral white blood cell counts were monitored, the nadir and recovery were similar in the presence or absence of DDC; however, recovery occurred sooner in the animals that had received DDC. Our data support the ability of DDC to modify the bone marrow toxicity of cis-platinum in normal mice. Experiments are in progress in tumor-bearing animals exploring the differential protection afforded by DDC between bone marrow and tumor.

Animals↗
PubMed1984

Quantification of alprazolam in serum or plasma by liquid chromatography.

A reversed-phase "high-performance" liquid-chromatographic assay for the quantification of alprazolam in serum or plasma is described. Serum or plasma is extracted with toluene/isoamyl alcohol (99/1 by vol), evaporated, and reconstituted in the mobile phase. The latter is washed with hexane, then subjected to reversed-phase liquid chromatography and ultraviolet detection at 202 nm. Either U-31485, an alprazolam analog, or lorazepam, a 3-hydroxybenzodiazepine, is satisfactory as internal standards. Major alprazolam metabolites and various other commonly used drugs do not interfere. The useful lower limit of sensitivity for quantification is 2.5 micrograms/L. Peak height and alprazolam concentration are linearly related from 2.5 to 100 micrograms/L. For 10 and 20 micrograms/L concentrations, within-run CVs were 1.4% and 0.9% and the between-runs CVs 4.8% and 3.2%. Steady-state serum concentrations ranged from 25 to 55 micrograms/L in patients taking 1.5 to 6.0 mg per day, orally. Preliminary data suggest the method is also suitable for analysis of the structurally similar triazolobenzodiazepine, triazolam.

Alprazolam↗
PubMed1984

Variability in relationships of arteries and nerves in the human orbit.

Orbits of humans were examined by dissection to study anatomic relationships of selected arteries and nerves. The usual paths of the ophthalmic artery and nasociliary nerve were superior to the optic nerve, but the ophthalmic artery crossed inferior to the optic nerve in 28% of the cases, a higher incidence than generally reported. The anterior ethmoidal artery and nerve almost invariably passed between the superior oblique and medial rectus muscles. When present, the posterior ethmoidal artery and nerve generally coursed above the superior oblique muscle.

Adult↗
PubMed1983

The impact of legal termination of pregnancy and of prenatal diagnosis on the birth prevalence of Down syndrome in Denmark.

A considerable reduction in number of livebirths for mothers over 35 was observed in Denmark from 1960 to 1980. Birthrates for those aged 35-39 fell by 58.8%, for those aged 40-44 by 78%. In 1979-1980 100 infants with Down syndrome were born among 116757 newborns, a birth prevalence of 0.86 per 1000, which was significantly lower than the incidence of 1.17 per 1000 when the prenatally diagnosed cases were included. The reduction was noticeable for the age group over 35 where it fell to 1.89 per 1000 for mothers 35-39 and 6.48 per 1000 for mothers over 40. The utilization of prenatal diagnosis was 72 per 100 livebirths for women 35 and older in the Copenhagen area and 56 per 100 livebirths for the rest of the country, with differences in different areas. The number of induced abortions for women 35 years and older was 9265 against 6597 livebirths. The estimated number of Down syndrome cases averted by unrestricted abortion was 61, twice the number prevented by amniocentesis (31), with the greatest impact for mothers over 40. An increased risk of Down syndrome for the age group 35-39 was observed when liveborn and prenatal cases were considered together showing an incidence of 6.89 per 1000, with the highest incidence in the Copenhagen area, 8.70 per 1000, more than double the incidence of 3.04 observed in Copenhagen from 1960 to 1971, for the same age group.

Abortion, Legal↗
PubMed1983

Hypothalamic-pituitary-gonadal function in relation to liver function in men with alcoholic cirrhosis.

Serum concentrations of oestrone, oestradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and sex hormone-binding globulin (SHBG) were significantly (P less than 0.01) raised in men with alcoholic liver cirrhosis (no. = 42) compared with age-matched controls (no. = 20). No significant difference was observed when comparing serum testosterone concentrations. Patients were divided into three groups in accordance with the severity of liver cirrhosis, using biochemical and clinical criteria. Patients with the best-preserved liver function (no. = 11) and patients with moderately affected liver function (no. = 18) had significantly (P less than 0.05) raised serum concentrations of testosterone, FSH, and LH when compared with both controls and patients with severely affected liver function (no. = 13). Serum concentrations of testosterone, FSH, and LH in the latter group showed no significant differences from the controls. Serum concentrations of oestrone and oestradiol were significantly (P less than 0.05) increased in all patient groups, and serum oestrone increased with decreasing liver function. No significant differences were observed concerning SHBG concentrations in the three groups of patients. Dexamethasone suppression did not change the concentration of testosterone significantly, but oestrone and oestradiol concentrations decreased significantly (P less than 0.01) in controls and patients. In patients, but not in controls, a significant (P less than 0.01) increase in FSH and LH concentrations was observed after dexamethasone suppression. The mean percentage increase of FSH and LH was higher the greater the severity of liver cirrhosis.

Adult↗
PubMed1983

Enhancement of heat sensitivity and modification of repair of potentially lethal heat damage in plateau-phase cultures of mammalian cells by diethyldithiocarbamate.

Diethyldithiocarbamate (DDC) is active both in vivo and in vitro in reducing the levels of enzymes such as superoxide dismutase (SOD) and glutathione peroxidase whose role in respiring cells is to remove toxic superoxide radicals and organic hydroperoxides. Although DDC, a copper-chelating agent, has been used to treat benign diseases, its potential as a heat sensitizer has not been fully explored. We have recently shown that the presence of 10(-3) M DDC for 2 hr causes a threefold reduction in the level of SOD in plateau-phase cultures of mammalian cells. At this concentration, the drug causes minimal toxicity but markedly affects both the shoulder and the slope of the heat survival curves. To explore another pathway of DDC sensitization, other than through reduced levels of SOD, we examined the repair of potentially lethal damage with and without DDC following exposure for 1 hr and 40 min at 43 degrees C. The repair, which progressed with a T 1/2 of about 10 hr, in either full medium or Hank's balanced salt solution (HBSS), in the absence of DDC, was completely blocked when DDC was added to the monolayers on completion of the heat exposure. DDC, in view of its ability to potentiate the effects of heat, is a potentially useful drug that could be used in an adjunctive setting with clinical hyperthermia.

Animals↗
PubMed1983

[Infectious diarrhea in childhood].

The present review summarizes the actual knowledge of infectious diarrhea in the pediatric age group. Main emphasis is placed on discussion of pathogenesis, etiology and therapy. Own data on etiology and clinical presentation of diarrhea in hospitalized children, so far not available from Switzerland, are presented and compared with results from other centres.

Age Factors↗