PubMed Health⌕ Search

Biomedical subjects

I Craig

Publications and source records attributed to I Craig.

At least 55 records · Page 3Linked to original sources
PubMed1990

Evaluation of two rapid methods for identifying and biotyping Haemophilus influenzae.

Several rapid method kits (one to four hours) have become available for the identification of Haemophilus and related genera. Two kits (the "Rapid NH" system and the "RIM Haemophilus" system), which include the identification and biotyping of H influenzae, were investigated for the rapid identification and biotyping of 193 isolates of H influenzae and the results compared with those obtained by more standard overnight methods. The kits were convenient to use and gave reliable and rapid speciation of all isolates. Both test systems were unreliable for biotyping: 42 isolates were wrongly biotyped by the RIM kit and 40 isolates wrongly biotyped by the rapid NH kit. It is concluded that the test kits may be useful for the rapid identification of H influenzae but that they are not reliable for the biotyping of this species.

Bacterial Typing Techniques↗
PubMed1990

Localization of the microsatellite probe DXS426 between DXS7 and DXS255 on Xp and linkage to X-linked retinitis pigmentosa.

The microsatellite marker DXS426 maps to the interval Xp21.1-Xp11.21, the chromosomal region which contains two loci for X-linked retinitis pigmentosa (XLRP; RP2 and RP3). We have refined the localization of DXS426 both physically, by mapping it to a deletion which spans the interval Xp21.3-Xp11.23, and genetically, by studying multiply informative crossovers which indicate that DXS426 lies between DXS7 and DXS255 (i.e., Xp11.4-Xp11.22). As this is the region which contains the RP2 gene, RP2 families could be identified on the basis of linkage of XLRP to DXS426. Multiply informative crossovers in two RP2 families indicate that the most likely location of the RP2 gene is between DXS426 and DXS7. DXS426 is therefore an important highly informative marker for the purposes of carrier detection and early diagnosis of RP2 and for the localization of the disease gene.

Base Sequence↗
PubMed1989

Isolation and characterization of a human variable copy number tandem repeat at Xcen-p11.22.

A subclone (M27B) has been isolated from a cosmid randomly selected from a library enriched for human X-chromosomal material. The subclone is extensively single-copy sequence, but also contains three complete copies and one partial copy of a 26-bp repeat, within which exists an inverted repeat having the potential to form a cruciform loop structure. Genomic sequences in this repeat region are apparently refractory to cloning, and rearrangements occurring during this process result in deletions. M27B detects multiple X-linked restriction fragments for a wide range of enzymes including MspI and HpaII. We have assigned the locus recognized by the probe (DXS255) to Xcen-Xp11.4 by mapping with a somatic cell hybrid panel and further refined its localization to Xp11.22 by in situ hybridization. The repeat sequence that is presumed to be responsible for the hypervariability observed does not show close similarity to other variable copy number tandem repeats described.

Base Sequence↗
PubMed1989

Molecular characterization of human X/Y translocations suggests their aetiology through aberrant exchange between homologous sequences on Xp and Yq.

Several DNA sequences from two homologous regions, localized on the distal part of the human X chromosome short arm and on the long arm of the Y chromosome, have been hybridized to DNAs from seven human-rodent hybrids containing human X; Y translocation chromosomes. Molecular characterization of the translocated chromosomes has revealed, in all but one case, transfer of the Y cluster of sequences and complete deletion of the corresponding X-chromosomal sequences. The possible role of X/Y homology in the aetiology of X; Y translocations is proposed.

Cell Line↗
PubMed1988

Linkage studies do not confirm the cytogenetic location of incontinentia pigmenti on Xp11.

Linkage studies have been performed in 5 incontinentia pigmenti (IP) families totaling 29 potentially informative meioses. Ten probes of the Xp arm were used, six of them were precisely localized on the X chromosome, using hamster X human somatic cell hybrids containing a broken X chromosome derived from an incontinentia pigmenti patient carrying an X;9 translocation [46,XX,t(X;9)(p11.21;q34)]. The following order for probes is proposed: pter - (DXS7, DXS146, DXS255) - IP1 - (DXS14, DXS90) - DXS106 - qter. The negative lod scores obtained exclude the possibility that in the families studied, the gene for IP is located in Xp11 or in the major part of the Xp arm.

Animals↗
PubMed1988

Mapping of 12 translocation breakpoints in the Xp21 region with respect to the locus for Duchenne muscular dystrophy.

Over 20 females have been reported to carry reciprocal X; autosome translocations with breakpoints in Xp21 and to suffer from Duchenne muscular dystrophy (DMD). We have positioned nine of these breakpoints with respect to the Duchenne gene by mapping probes from the DMD region against a panel of somatic cell hybrids, each containing one of the translocation chromosomes from a different female patient; further information has also been obtained by in situ hybridization, including the breakpoint location in a tenth DMD patient. We have also characterized two translocation breakpoints that lie in the same chromosomal region but which are not associated with the expression of DMD. All the DMD-associated translocation breakpoints examined lie at several sites within the DMD locus and between the two non-DMD breakpoints.

Cell Line↗
PubMed1987

Isolation and characterization of a steroid sulfatase cDNA clone: genomic deletions in patients with X-chromosome-linked ichthyosis.

We have isolated several cDNA clones from a lambda gt11 expression library by screening with antibodies prepared against the microsomal enzyme steroid sulfatase, which is deficient in classical X-chromosome-linked ichthyosis patients. One of these clones (p422) has been assigned by mapping with a somatic cell hybrid panel and by in situ hybridization to Xp22.3. Clone p422 therefore has a coincident localization with the previously identified locus for steroid sulfatase expression in the region of the X chromosome escaping from inactivation. Twelve steroid sulfatase-deficient patients, including eight cases of classical ichthyosis, were found to be deleted for genomic sequences detected by the clone.

Chromosome Deletion↗
PubMed1987

Molecular heterogeneity of translocations associated with muscular dystrophy.

Individual translocation chromosomes from six girls suffering from Duchenne or Becker muscular dystrophy (DMD or BMD) have been isolated in human-mouse somatic cell hybrids. DNA prepared from these hybrids was probed with sequences physically close to the locus; these include a junction fragment from the site of the X:21 translocation (pXJ1) and subclones from the pERT 87 (DXS164) region which are absent in a minority of male DMD patients. Both sets of sequences mapped within the area defined by the translocation breakpoints, confirming their close proximity to the DMD and BMD loci. Furthermore, the X chromosome breakpoints of the translocations can be divided into three categories depending upon their position in relation to the sequences recognised by pXJ1 and pERT 87. The genomic target disrupted by the translocations examined here is a minimum of 176 kb.

Chromosome Mapping↗
PubMed1987

Identification of incomplete coding sequences for steroid sulphatase on the human Y chromosome: evidence for an ancestral pseudoautosomal gene?

A cDNA clone (p422) containing about 200bp of coding sequences for steroid sulphatase (STS) has been isolated from a lambda gt11 expression library by antibody screening and has been assigned by mapping with a somatic cell hybrid panel and by in situ hybridization to Xp22.3; a localization coincident with the previously identified locus for STS expression. Although no significant hybridization of this clone to the Y chromosome was observed, p422 has been used to isolate a longer cDNA clone and genomic sequences which do recognize Y-specific restriction fragments. An abbreviated STS gene has been localized to Yq11.2. The coding sequences for the human enzyme shows little homology to sequences in mice.

Animals↗
PubMed1987

The mammalian Y chromosome: molecular search for the sex-determining gene--summary and perspectives.

Other presentations to this symposium have indicated that the search at the molecular level for the pivotal regulatory, or structural, gene responsible for determining the development of the undifferentiated gonad has been joined in earnest. It is also clear that genes on the Y chromosome are involved in processes other than primary determination of the testis. In this summary, we will review briefly 'the molecular search for the sex-determining gene' and consider the approaches that are available and the achievements that have been made in the areas relevant to an understanding of the roles and significance of other Y-located genes. The availability of molecular and physical mapping data also allow an examination of the evolutionary relationship of the mammalian X and Y chromosomes and a consideration of the possible homologies between the human and mouse Y chromosomes.

Animals↗
PubMed1987

Pulmonary permeability edema in a large animal model of nonpulmonary sepsis. A morphologic study.

Morphologic studies were undertaken in a sheep model of pulmonary permeability edema (PPE) induced by cecal ligation and perforation. Biopsies taken every 24 hours through 96 hours following induction of sepsis showed, at 24 hours, interstitial edema accompanied by widespread aggregation of polymorphonuclear leukocytes. This was confirmed by electron microscopy, which also demonstrated endothelial cell swelling, platelet aggregation, and fibrin deposition. By 48 hours, a "thromboangiitis" had developed that persisted through 96 hours. In vitro pulmonary angiograms done at 60 and 96 hours showed multiple filling defects; it was possible to demonstrate that these defects corresponded to the "thromboangiitis." These thrombotic lesions, which were not the result of embolization from indwelling lines, closely resembled vascular changes described in the adult respiratory distress syndrome. It is believed that this is the first time that such lesions have been described in a model of PPE resulting from nonpulmonary sepsis.

Animals↗
PubMed1986

Muscular dystrophy in girls with X;autosome translocations.

Twenty known cases of X;autosome translocations with breakpoints at Xp21 associated with Duchenne or Becker muscular dystrophy in girls are reviewed. The variable severity described for different persons may reflect differences in X inactivation or in the nature of the genomic target disrupted. High resolution cytogenetic studies on 12 cases indicate breakpoints on the X chromosome at Xp21.1 or Xp21.2. Translocation chromosomes from several of these cases have been isolated in human/mouse somatic cell hybrids. Molecular heterogeneity in the breakpoint positions has been established by probing DNA from these hybrids with a range of cloned sequences known to be located within, or closely linked to, the Duchenne region. The minimum separation between the most distal and the most proximal breakpoints is 176 kb suggesting that, if a single gene is involved, it must be large. Alternatively, the translocations may affect different genes, or confer alterations to regulatory sequences which operate at a distance.

Chromosome Banding↗
PubMed1986

Localization of the human tyrosine hydroxylase gene to 11p15: gene duplication and evolution of metabolic pathways.

Phenylalanine hydroxylase (PAH) and tyrosine hydroxylase (TH) are consecutive enzymes in the metabolic pathway leading to the production of catecholamine neurotransmitters. A comparison of recently available sequence data of these enzymes in the rat indicates about 70% homology in the 3' coding regions. We have localized TH by in situ hybridization to human chromosome region 11p15. Consideration of this assignment and that of PAH to chromosome 12, together with the known distribution of other pairs of related genes on these two chromosomes, provides convincing evidence of their ancestral relationship and suggests a role for gene duplication in the diversification of metabolic pathways in the vertebrate ancestors of mammals.

Animals↗
PubMed1986

Pulmonary microvascular fluid flux in a large animal model of sepsis: evidence for increased pulmonary endothelial permeability accompanying surgically induced peritonitis in sheep.

To characterize some of the remote effects of systemic sepsis on the lung, we evaluated changes in pulmonary microvascular fluid flux before and during sepsis secondary to a peritoneal focus of inflammation in sheep. We induced peritonitis by cecal ligation, perforation, and devascularization. During a subsequent 72-hour study period, both the mean blood pressure and the pulmonary capillary wedge pressure were unchanged, while the cardiac index increased slightly. The PaO2 fell by 48 hours (98 +/- 8 to 84 +/- 10 mm Hg; p less than 0.05) (mean +/- SD) and subsequently remained low throughout the experiment. Simultaneously, pulmonary lymph flow increased by 24 hours (11.5 +/- 4.9 to 26.7 +/- 13 ml/hr; p less than 0.05) and remained elevated throughout the experiment while [L/P] total protein ratios remained unchanged at 24 hours (baseline: 0.59 +/- 0.15 at 24 hours: 0.65 +/- 0.16). Morphologic examination of the lung showed that this model of peritonitis was characterized by neutrophil emigration into the pulmonary interstitium by 24 hours and interstitial edema by 48 hours. Therefore this model of bacterial peritonitis in sheep demonstrates that one of the remote effects of surgically induced systemic sepsis is an increase in permeability of the pulmonary microvascular membrane.

Animals↗
PubMed1981

Steroid sulphatase levels in XX males, including observations on two affected cousins.

Quantitative assays of steroid sulphatase in XX males have shown that some individuals have two functional loci, and others only one. Two affected cousins, who cannot share the same X-chromosome, nevertheless have male levels of steroid sulphatase, suggesting functional abnormality of the X chromosome. The hypothesis is advanced that these and other unusual features of X-chromosome function in some XX males, could be explained if such cases were due to an autosomal mutation, exercising its effect by causing abnormal inactivation of a subterminal area of Xp which normally escapes the inactivation process.

Arylsulfatases↗