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Biomedical subjects

G Newton

Publications and source records attributed to G Newton.

At least 19 recordsLinked to original sources
PubMed1994

Characterization of human and mouse cartilage oligomeric matrix protein.

Cartilage oligomeric matrix protein (COMP) is a 524,000-Da protein that is expressed at high levels in the territorial matrix of chondrocytes. The sequences of rat and bovine COMP indicate that it is a member of the thrombospondin gene family. In this study, we have cloned and sequenced human COMP. Phylogenetic analysis using progressive sequence alignment and two parsimony-based algorithms indicates that the COMP gene and a precursor of the thrombospondin-3 and -4 genes were produced by a gene duplication that occurred 750 million years ago. An interspecific backcross mapping panel has been used to map the murine COMP gene to the central region of mouse chromosome 8. Southern blot analysis of a somatic cell hybrid DNA panel and in situ hybridization to human metaphase chromosomes indicate that the human COMP gene is located on chromosome 19 in band p13.1. These data confirm and extend the known regions of homology between human and mouse chromosomes and establish that COMP, like thrombospondin-1, -2, -3, and -4, is present in the human and mouse genomes.

Animals↗
PubMed1994

Basal and thrombin-stimulated platelet cell calcium.

To study platelet cell calcium in dogs, we measured the fura-2-determined calcium concentration (Cai) in platelets derived from blood drawn through indwelling arterial catheters in four dogs. Platelet samples were obtained 3 days a week for 39 days. Canine platelet Cai averages 40.5 +/- 1.7 nmol/L when corrected for extracellular fura-2 dye (n = 46); this mean is significantly smaller than the value obtained without such a correction (50.2 +/- 2.0 nmol/L, P < .05). The amplitude of thrombin-induced Ca2+ transients is proportional to basal Cai, increasing 4.9 +/- 0.9 nmol/L peak Ca2+ per nmol/L increase in baseline Ca2+.

Animals↗
PubMed1992

Isolated olfactory groove neurilemmoma.

A case of neurilemmoma arising from the olfactory groove presenting with headache, vomiting, and visual impairment in a thirty-seven-year-old man is reported. His clinical manifestations are described, with a brief review of three other cases reported in the literature so far.

Adult↗
PubMed1992

Ossifying fibroma of the sella turcica.

Ossifying fibroma of the sellar turcica is extremely rare. There are only sporadic case reports in the literature. One such case simulating pituitary adenoma is presented in an 18-year-old girl.

Adenoma↗
PubMed1992

Lateral cervical meningocele.

Lateral cervical meningocele is an extremely rare developmental anomaly. We could find only one such case protruding from an enlarged C2-3 intervertebral foramen. It may be confused with an extradural cyst or cystic hygroma. Direct needling may introduce infection and thereby pyogenic meningitis and so should be avoided. Similarly, incision and drainage may transform it into cerebrospinal fluid fistula. A computed tomography scan is the most fruitful form of investigation for confirmation and localization of the disease. A lumboperitoneal shunt or water tight closure of the dural sac at the neck is the recommended procedure of choice.

Child↗
PubMed1992

Long-term results of the Manchester knee. Surface arthroplasty of the tibiofemoral joint.

Unicompartmental knee replacement is increasing in popularity. Long-term analysis of an early bi-compartment variety, the Manchester knee, therefore has relevance. One hundred fifty-six consecutive Manchester knee replacements were observed, 47 for longer than ten years. Using survivorship tables, the authors found that the annual failure rate did not increase during the ten-year period. The cumulative success rate was 73% for all knees and 69% for the osteoarthritic ones. The main cause of failure was subsidence. Correction of mechanical axis had no effect on the outcome. Polyethylene wear was not significant clinically or on measurement of retrieved specimens.

Adult↗
PubMed1991

In vivo assembly of the cytochrome d terminal oxidase complex of Escherichia coli from genes encoding the two subunits expressed on separate plasmids.

The cytochrome d terminal oxidase complex is a heterodimer located in the cytoplasmic membrane of Escherichia coli. Subunit II of the cytochrome d terminal oxidase complex was expressed independently of subunit I of the complex. It was found that the polypeptide is produced and is associated with the cytoplasmic membrane in the absence of subunit I, and is not associated with any of the three cytochrome components of the complex. Oxidase activity and heme binding are restored when the subunit I is expressed in the same cells using a second compatible plasmid. It has been previously demonstrated that subunit I, expressed in the absence of subunit II, contains cytochrome b-558, one of the three heme prosthetic groups found in the oxidase. Association of the two other heme moieties, cytochromes b-595 and d, apparently requires the association of the two subunits, and must be a late step in the assembly of the membrane-bound protein. It was also shown that under heme-deficient conditions, the two polypeptide subunits are expressed and are associated with the cytoplasmic membrane.

Cell Membrane↗
PubMed1991

Analysis of the topology of the cytochrome d terminal oxidase complex of Escherichia coli by alkaline phosphatase fusions.

The cytochrome d complex of Escherichia coli is a heterodimer located in the bacterial cytoplasmic membrane, where it functions as a terminal oxidase of the aerobic respiratory chain. The topology of each of the two subunits of the cytochrome d complex was analysed by the genetic method involving alkaline phosphatase gene fusions. These fusions were generated by both an in vivo method using the transposon TnphoA and an in vitro method of construction. A total of 48 unique fusions were isolated and the whole-cell alkaline phosphatase-specific activities were determined. Data from these fusions, in combination with information from other studies, provide the basis for two-dimensional models for each of the two subunits, defining the way in which the subunits fold in the inner membrane of E. coli.

Alkaline Phosphatase↗
PubMed1991

Radiographic sign of persistent soft-tissue imbalance after knee replacement.

We report on the radiological findings in a series of 871 consecutive primary condylar knee replacements followed up for an average of four years. A new radiological sign has been identified, consisting of a smoothly tapering wedge of cement visible beneath the horizontal portion of the tibial component on the anteroposterior radiograph. This was found in 25.4% of our cases and appears to indicate a persistent soft-tissue imbalance following condylar arthroplasty of the knee. The cement-wedge sign was associated with a highly significant increase in radiolucent lines at the tibial cement-bone interface.

Bone Cements↗
PubMed1991

Osteoclastoma of occipital bone.

Osteoclastoma of the calvarial bone of membranous origin is a rare entity. This paper presents a case of osteoclastoma of the occipital bone and a brief review of literature.

Child↗
PubMed1991

Cystic meningiomas in infancy.

A suprasellar meningioma with multiple intratumoral cysts in a 6-month-old boy is reported. A review of literature disclosed only 11 cases so far. They showed a characteristic predominance in males and predominance of fibroblastic type on pathological examination. Intratumoral cystes are less common than peritumoral cysts. The various hypothesis regarding cyst formation are discussed.

Cysts↗
PubMed1990

HIV and surgeons.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗