Late replication studies and esterase D levels in a case of unbalanced X;autosome translocation, 46,X,t(X;13)(q27;q12).
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Carboxylesterase↗
Biomedical subjects
C J Chapman
Publications and source records attributed to C J Chapman.
Equilibria between ionophore A23187 and divalent cations: stability of 1:1 complexes in solutions of 80% methanol/water.
The cation complexation equilibria between ionophore A23187 and several alkaline earth and first transition series divalent cations have been investigated. Absorption and fluorescence spectroscopy were used to monitor the reactions which were studied in solutions of 80% methanol/water, at 25 degrees C, and under conditions of controlled ionic strength and pH. Titration of the ionophore with divalent cations results first in formation of the dimeric species MA2 and subsequently in the formation of MA+ by disproportionation of the first product. With Zn2+, Ni2+, and Co2+ (above pH approximately 6), a third species is detected which is postulated to be MA.OH. The existence of this species with Mn2+ and alkaline earth cations is uncertain. For formation of MA2, the second stepwise stability constant is similar to or exceeds the first value with all cations studied. However, it is possible to isolate the first reaction and determine accurate stability constants by working at an ionophore concentration of 3 X 10(-8) M or less and by employing pH values which preclude interference by the mixed ionophore/hydroxide species. Under these conditions, the relationship between log KMA' and pH is linear and displays a slope of 1.0. pH-independent stability constants were calculated by using pH-dependent stability constants and the known value of the ionophore's protonation constant in this solvent. The logarithms of the values obtained ranged from 7.54 +/- 0.06 for Ni2+ to 3.60 +/- 0.06 for Ba2+. The selectivity sequence and relative affinities (in parentheses) for the species MA+ are as follows: Ni2+ (977) greater than Co2+ (331) greater than Zn2+ (174) greater than Mn2+ (34) greater than Mg2+ (1.00) approximately equal to Ca2+ (0.89) greater than Sr2+ (0.20) greater than Ba2+ (0.11). Data are discussed in comparison to other studies on the complexation properties of A23187 and in terms of their significance to interpreting the transport properties of this ionophore.
Calcimycin↗
The use of a DNA marker for carrier diagnosis in an X-linked disorder: Norrie's disease.
We report a family with the X-linked eye disorder Norrie's disease, in which DNA analysis enabled the distinction to be made between female carriers and non carriers. There was perfect cosegregation of the disease gene and the restriction fragment length polymorphism DXS7 which is recognised by the probe L1.28. Adding our data to those already on record, the lod score for linkage between DXS7 and Norrie's disease reaches 5.6, for a recombination fraction of 0.0. We anticipate that DNA testing will become a major investigative tool in genetic counselling.
Blindness↗
Partial monosomy 12p13.1----13.3.
We describe a 27 month old female child with partial monosomy for the short arm of chromosome 12: 46,XX,del(12)(p13.1----p13.3). She differs from the eight cases described by others, in that she is less severely affected. Her main clinical features are developmental delay, protruding tongue, strabismus, slightly unusual facies, slight micrognathia, and speech delay.
Child, Preschool↗
Secular trends in anencephalus prevalence in New Zealand.
Although the aetiology of anencephalus is unknown, changes in prevalence over time are thought to provide strong evidence of the effect of environmental factors in causation. In a number of countries the rate of this neural tube defect is declining. The rate in New Zealand has also fallen significantly (p less than 0.001) from 1.17/1000 total births in 1968 to 0.39/1000 in 1983, with the greatest decrease occurring in the female rate (approximately 4.16% per year). The aetiological implications of these findings and their consequences for programmes of prenatal diagnostic testing and maternal screening are discussed.
Abortion, Therapeutic↗
Studies on three rare fragile sites. 2q13, 12q13, and 17p12 segregating in one family.
Three fragile sites 2q13, 12q13, and 17p12 were found in one family. In the index case, who was first investigated in 1969 for low birth weight and bilateral inguinal hernia, three tissues were examined, blood, marrow, and skin. Three of the family have been reinvestigated after 17 years. Cultures for sister chromatid exchange (SCE) and the effects of aphidicolin, fluorodeoxyuridine (FUdR), bromodeoxyuridine (BrdU), and methotrexate on the frequency of the fragilities were studied. The mother of the index case who is an obligate carrier for the fragile 2q13 does not express it in folate/thymidine deficient medium. Further studies on her using a lymphoblastoid cell line, showed that there was a reduced level of fragility of 12q13 and 17p12 in B-lymphocytes compared to T-lymphocytes. Excess thymidine and FUdR when added to the lymphoblastoid cell line did not induce the 2q13. These studies also confirm the induction of a range of common fragile sites by treatment with aphidicolin, showing in addition homozygosity for at least 3p14, 6q26, 16q23, and Xp22. There were no detectable increases in the SCE rate between individuals with fragile sites and the five controls tested. There was no history of cancer or phenotypic abnormalities in the family.
Adolescent↗
Inheritance of atrioventricular conduction time in Tokelau Islanders.
The inheritance of A-V conduction time in Polynesians has been examined, using ECGs taken from the population of the Tokelau Islands. As has been demonstrated in other racial groups, A-V conduction time was influenced by sex, age, and heart rate. Complex segregation analysis provides evidence for a significant polygenic influence on A-V conduction, but no evidence for a major gene. Familial correlations and commingling analysis are in agreement with this conclusion. The heritability of A-V conduction time was 0.46. The hypothesis of Møller & Heiberg (1980a) that a major gene could be influencing A-V conduction, is not supported by these data.
Atrioventricular Node↗
Effect of membrane association on the stability of complexes between ionophore A23187 and monovalent cations.
The monovalent cation complexation properties of ionophore A23187 in methanol-water (65-95% w/w) and bound to unilamellar vesicles of dimyristoylphosphatidylcholine (DMPC) are contrasted. In both solution and vesicle-containing systems, 1:1 complexes between the ionophore and Li+ or Na+ predominate. The analogous complexes with K+, Rb+, and Cs+, which exist in methanol, are not detected on DMPC vesicles by changes in the absorption or fluorescence emission spectra of the ionophore. In solution, the logarithms of stability constants (log KMA) for both the LiA and NaA complexes increase by 1.5 units over the range of solvent polarity encompassed by 65% methanol-water to methanol. Selectivity for Li+ vs. Na+ is constant at a ratio of 5 in these solutions. On DMPC vesicles, selectivity for Li+ vs. Na+ is improved 15-fold with log KbLiA (3.23 +/- 0.03, T = 25 degrees C, mu = 0.05 M) being comparable to the value obtained in 80% methanol-water. In the latter solvent, increasing ionic strength (0.005-0.085 M) has little effect on log KLiA or log KHA but increases these constants by 0.4-0.5 unit in the DMPC vesicle system. Transition from the vesicle liquid-crystalline to gel-phase state reduces log KbLiA and log KbNaA by approximately 0.6 unit but has no effect on log KbHA. Thermodynamic parameters for formation of HA, LiA, and NaA in 80% methanol-water and on DMPC vesicles are reported. Analysis of these data and related considerations suggests that differences in the membrane interaction energies of particular ionophore species dominate in establishing the observed difference in complexation properties between the solution and vesicle-containing systems.
Biological Transport↗
Vesicoureteric reflux: segregation analysis.
Complex segregation analysis was applied to data from 88 families containing at least one person with vesicoureteric reflux. Analysis showed that a single major locus was the most important causal factor in this condition, with the mutant allele being dominant to the normal allele and having a gene frequency of about 0.16%. Forty-five percent of gene carriers will have vesicoureteric reflux and/or reflux nephropathy as adults and 15% will develop renal failure, compared to 0.05% and 0.001%, respectively, for those not carrying the gene. This analysis confirms the importance of screening close relatives of persons with proven vesicoureteric reflux or reflux nephropathy.
Adolescent↗
A complex structural rearrangement of chromosome 4 in a woman without phenotypic features of Wolf-Hirschhorn syndrome.
A 32-year-old mentally retarded woman was found to have a complex rearrangement of one chromosome 4. Her karyotype is interpreted as 46,XX,inv(4) (pter----p14::q12----p14::q12----qter) del (4) (pter----15.33::p15.2----qter). Clinically she does not show the features of the Wolf-Hirschhorn syndrome. Her phenotype and cytogenetic findings are compared with 2 other reported cases of 4p-without Wolf-Hirschhorn syndrome.
Adult↗
Direct intrachromosomal duplication of 16q and heritable fragile site fra (10) (q25) in the same patient.
We describe a woman with profound mental retardation and a direct duplication of 16q and fragile site fra(10)(q25). The identification and possible origin of the duplicated 16q is discussed along with the clinical manifestations. To our knowledge this is the first direct duplication of 16q to be reported. The karyotype is shown to be 46,XX, dir dup (16) (q11.2----q13).
Adult↗
Diagnosis of myocardial infarction from serum creatine kinase MB isoenzyme (CKMB) measurement.
The cardiospecific isoenzyme MB of creatine kinase (CKMB) has previously been shown to be of value in the diagnosis of myocardial infarction (MI). We studied 418 admissions to a coronary care unit (CCU) with suspected MI and calculated the sensitivity, specificity and positive and negative predictive values for several CKMB test functions. Several functions performed better than any combination of the other enzymes in common use. 97% of patients achieving a CKMB activity of at least 15 U/l did so between 6 and 30 h following the onset of symptoms. The present study confirms that the use of the CKMB isoenzyme leads to an earlier and more accurate diagnosis or exclusion of MI compared to the "cardiac enzyme series". The timing of blood sampling for CKMB estimation is also discussed.
Aged↗
Location and dynamics of ionophore A23187 bound to unilamellar vesicles of dimyristoylphosphatidylcholine.
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Calcimycin↗
Ethnic differences in the incidence of cleft lip and/or cleft palate in Auckland, 1960-1976.
The incidence of facial clefts among live births in the Auckland urban area has been studied for the years 1960-1976. After correction for ascertainment, the live-born incidence of non-syndromal cleft palate among Maoris was 1.867/1000, and among Europeans it was 0.643/1000. The incidences for non-syndromal cleft lip, with or without cleft palate, were 0.397/1000 for Maoris, and 1.195/1000 for Europeans. The sex ratio for cleft palate showed the usual female preponderance, although there was evidence of heterogeneity between the races. Cleft lip occurred more commonly among males. Birth rank, maternal age, and paternal age had no apparent effect on the incidences, and there were no significant secular or seasonal changes in incidence.
Cleft Lip↗
Computer assessment of alternative rubella vaccination strategies in New Zealand.
Results from a dynamic computer model of rubella vaccination programmes indicate that consideration should be given to vaccinating all one-year-old girls and boys and revaccinating all girls at about 11 years of age, as well as continuing with the programme for susceptible women in the childbearing age group. With vaccine-induced immunity decaying at about 1% annually, the vaccination of 80 to 95% of all one-year-olds, 95% of 11 year old girls, and 5% of women aged 15 to 33 annually is expected to reduce congenital rubella syndrome deformities to less than 5% of the 1980 incidence by 1994, and to negligible levels thereafter. In comparison, continuation of the present scheme may reduce deformities to only 69% of 1980 levels by 1994 with a slow decline to 25% in 2010. (The 1980 levels used were computer generated to eliminate short-term fluctuations, and do not apply to actual figures from that year.) For convenience and better compliance, measles vaccine and the initial rubella vaccine may be given in combined form at 15 months without altering the effect of either. The rate of decay of immunity after vaccination is critically important in congenital rubella syndrome prediction, so that further accurate monitoring of immune status and congenital rubella incidence is essential.
Adolescent↗
Familial paracentric inversion of 1p.
We report a paracentric inversion of 1p in a boy with mild mental retardation. The chromosome aberration was identified by high resolution chromosome banding, and was also present in his phenotypically normal mother and other relatives. The boy's karyotype was considered to be 46,XY,inv(1) (p31,2p36.22) ISCN (1981).
Child, Preschool↗