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Biomedical subjects

J S Reid

Publications and source records attributed to J S Reid.

At least 19 recordsLinked to original sources

Safe placement of proximal tibial transfixation wires with respect to intracapsular penetration.

OBJECTIVES: To determine the safe zone for transfixation wires in the proximal tibia to avoid intracapsular penetration. METHODS: The material consisted of five fresh cadaver knees (two paired) and seven knees of volunteer subjects (three paired). High-resolution magnetic resonance imaging (MRI) was performed on each knee after distension with a gadolinium solution. The distance d from the subchondral bone to the insertion of the reflected joint capsule was measured. Selected cadaver knees were then anatomically sectioned to correlate the MRI findings with anatomic measurements. RESULTS: On the anteromedial side of the knee, the distance from the reflected joint capsule to the subchondral bone was less than eleven millimeters in all specimens except one. Posteromedially, d was smaller and ranged from two to four millimeters. On the lateral side of the knee anterior to the proximal tibiofibular joint, this distance ranged from six to nine millimeters. In all knees but two, d was greatest at the posterior aspect of the proximal tibiofibular joint, ranging from eight to thirteen millimeters. In one volunteer knee, the septum that separates the knee joint from the proximal tibiofibular joint was either torn or attenuated, resulting in complete communication between these two synovial cavities. CONCLUSIONS: Proximal tibial transfixation wires away from the tibiofibular joint are likely to be extraarticular if kept greater than fourteen millimeters from the subchondral bone. In the region of the proximal tibiofibular joint, a safe distance is unclear because it is difficult to know preoperatively which knee has a torn septum.

Bone Wires↗

Accuracy of hospital discharge data for cancer registration and epidemiological research in Northern Ireland.

BACKGROUND: Cancer registries provide a basis for many epidemiological studies in cancer. Electronic data provide for prompt, economical data capture for disease registries; doubts, however, exist about their data quality. MATERIALS AND METHODS: We examined the accuracy for cancer registration of a subset of 7043 electronically captured hospital discharge data. RESULTS: Note availability was 82%. Of the notes available for examination demographic data accuracy was high; however, 7.4% of cases coded on discharge as cancer had no malignancy recorded in case notes while 4. 1% had in-situ or benign tumors. Almost a third had some inaccuracy in coding tumor site. Prevalent cases accounted for 17.2% of cases examined reflecting a new registry. Electronic data capture reduces time spent examining notes; only 40% of cases notified from PAS required a quick validation check. It enhances data completeness; without electronic discharge data 11.5% of the final database would have been missed. The validation check prevented overinflation of the cancer registration database by 7.5%. Measures of accuracy in the final database were high. CONCLUSION: This study shows that discharge data are a valuable data source for cancer registries but require a targeted note review aimed at cases without corroborating data.

Adult↗

Caries detector dyes--an in vitro assessment of some new compounds.

Previous studies have shown that the caries detector dyes, basic fuchsin and acid red, lack specificity. Accordingly, their clinical use can lead to the unnecessary removal of sound tissue. In the present study, the specificity of three further dyes, Carbolan Green, Coomassie Blue and Lissamine Blue was studied. Carious dentine was removed in vitro by means of rotary instruments until the cavities were deemed caries free by conventional clinical criteria. Experimental dyes were applied to the cavity floors, all of which became stained. Stained dentine was removed from half the cavity by means of a burr, the other half remaining as a control. Further stain was then applied and the procedure repeated until no further reduction of the staining of the cavity floor could be achieved. Light microscopy of ground sections of experimental teeth showed that sound tissue had been removed unnecessarily from the experimental half of the cavity due to the lack of specificity of these dyes. This lack of specificity of staining was similar to basic fuchsin and acid red. Only Carbolan Green showed possible differential staining between control and experimental sites, but this was not caries specific. If a clinically useful dye is to be developed, it would need to specifically stain either bacteria in infected dentine and/or the carious degradation products of dentine matrix.

Aniline Compounds↗

Molecular characterisation of a membrane-bound galactosyltransferase of plant cell wall matrix polysaccharide biosynthesis.

Galactomannan biosynthesis in vitro is catalysed by membrane preparations from developing fenugreek seed endosperms. Two enzymes interact: a GDP-mannose dependent (1-->4)-beta-D-mannan synthase and a UDP-galactose dependent (1-->6)-alpha-D-galactosyltransferase. The statistical distribution of galactosyl substituents along the mannan backbone, and the degree of galactose substitution of the primary product of galactomannan biosynthesis appear to be regulated by the specificity of the galactosyltransferase. We now report the detergent solubilisation of the fenugreek galactosyltransferase with retention of activity, the identification on gels of a putative 51 kDa galactosyltransferase protein, and the isolation, cloning and sequencing of the corresponding cDNA. The solubilised galactosyltransferase has an absolute requirement for added acceptor substrates. Beta-(1-->4)-linked D-manno-oligosaccharides with chain lengths greater than or equal to 5 acted as acceptors, as did galactomannans of low to medium galactose-substitution. The putative galactosyltransferase cDNA encodes a 51282 Da protein, with a single transmembrane alpha helix near the N terminus. We have also confirmed the identity of the galactosyltransferase by inserting the cDNA in frame into the genome of the methylotrophic yeast Pichia pastoris under the control of an AOX promoter and the yeast alpha secretion factor and observing the secretion of galactomannan alpha-galactosyltransferase activity. Particularly high activities were observed when a truncated sequence, lacking the membrane-spanning helix, was expressed.

Amino Acid Sequence↗

The role of ultrasonography in thromboembolic disease management in the orthopaedic patient.

Deep venous thrombosis (DVT) is a well-recognized contributor to increased morbidity and mortality following trauma and elective musculoskeletal procedures. Ultrasound has become a popular noninvasive modality for use in the detection of symptomatic DVT. However, its use as a screening tool in asymptomatic or postoperative patients has been questioned. The reliability of ultrasound rests mainly in the ability of the technicians performing the exam. Ultrasound has been shown to be less reliable in identifying asymptomatic calf thrombi; in institutions where ultrasound DVT surveillance is not performed routinely, the technique suffers from inadequate sensitivity to be utilized for routine screening purposes. Recognition of patients at high risk for DVT, along with an understanding of the limitations of ultrasound, will allow for appropriate clinical application of this modality.

Humans↗

Multiple endocrine neoplasia syndrome type IIb: a case report.

Multiple endocrine neoplasia type IIb (MEN IIb) is a syndrome, part of which can involve neoplastic change in the thyroid and adrenal glands. It has unusual oro-facial manifestations including mucosal neuromata on the lips, cheeks and tongue. A child aged 3 years and 10 months presented with mucosal tags at the corners of the mouth, early eruption of permanent teeth, malocclusion and facial asymmetry. Biopsy of the excess mucosal tissue suggested a diagnosis of either MEN type IIb or neurofibromatosis. Genetic testing eventually confirmed MEN type IIb. The patient has been followed up regularly for 9 years. He has developed modular lesions on his tongue and irregular enlargement of his lower lip, but to date there have been no signs of tumour development. This report emphasizes the importance of thorough examination of the oral mucosa and follow-up of any abnormalities.

Biopsy↗

A xyloglucan oligosaccharide-active, transglycosylating beta-D-glucosidase from the cotyledons of nasturtium (Tropaeolum majus L) seedlings--purification, properties and characterization of a cDNA clone.

A beta-D-glucosidase has been purified to apparent homogeneity from the cotyledons of germinated nasturtium (Tropaeolum majus L.) seedlings during the mobilization of the xyloglucan stored in the cotyledonary cell walls. The purified protein (Mr 76, 000; a glycoprotein; pl > 9.5; apparent pH optimum 4.5; temperature optimum 30 degrees C) catalysed the hydrolysis of p-nitrophenyl-beta-D-glucopyranoside, cello-oligosaccharides, beta-linked glucose disaccharides, and certain xyloglucan oligosaccharides. Glucose disaccharides with different linkages were hydrolysed at different rates [(1-->3) > (1-->4) > (1-->2) > (1-->6)] with significant transglycosylation occurring in the early stages of the reaction. Cello-oligosaccharide hydrolysis was also accompanied by extensive transglycosylation to give transitory accumulations of higher oligosaccharides. At least some of the glycosyl linkages formed during transglycosylation were (1-->6)-beta. Xyloglucan oligosaccharides xylose-substituted at the non-reducing terminal glucose residue (XXXG, XXLG, XLXG and XLLG, where G is an unsubstituted glucose residue, X is a xylose-substituted glucose residue, and L is a galactosylxylose-substituted glucose residue) were not hydrolysed. Some xyloglucan oligosaccharides with an unsubstituted non-reducing terminal glucose residue (GXXG, GXLG and GXG) were hydrolysed, but others (GLXG and GLLG) were not. This indicated steric hindrance by L but not X substitution at the glucose residue next to the one at the non-reducing end of the oligosaccharide. Hydrolysis of xyloglucan oligosaccharides was not accompanied by transglycosylation. Natural xyloglucan subunit oligosaccharides (XXXG, XXLG, XLXG, XLLG) were totally degraded to their monosaccharide components when treated with nasturtium beta-D-galactosidase. (Edwards et al (1988) J. Biol. Chem. 263, 4333-4337), followed by alternations of nasturtium xyloglucan-specific alpha-xylosidase (Fanutti et al (1991) Planta 184, 137-147) and this enzyme. Several extensively overlapping cDNA clones were obtained by RT-PCR and by screening cDNA libraries. A composite, full-length DNA had an open reading frame of 1962 bp, encoding a polypeptide of 654 amino acids, including all N-terminal and internal sequences obtained from the purified beta-glucosidase protein, and a motif resembling plant signal sequences thought to direct proteins to the cell wall. Database searches revealed homology with beta-glucosidases from several sources (plant, bacteria, yeast), notably with glycosylhydrolases of 'Family 3', according to the classification of Henrissat (Henrissat (1991) Biochem. J. 280, 309-316). There was strong sequence homology with a beta-glucan exo-hydrolase from barley (Hrmova et al. (1996) J. Biol. Chem. 271, 5277-5286). The nasturtium beta-glucosidase is ascribed a role in xyloglucan mobilization, and its interaction with the alpha-xylosidase and the beta-galactosidase is modelled.

Amino Acid Sequence↗

Multicenter clinical comparison of sedative and analgesic effects of medetomidine and xylazine in dogs.

OBJECTIVE: To evaluate analgesic and sedative effects of medetomidine hydrochloride in dogs and to compare effects with those of xylazine hydrochloride. DESIGN: Randomized, controlled trial. ANIMALS: 184 dogs that required sedation or analgesia for completion of minor diagnostic or therapeutic procedures. PROCEDURE: Dogs were sedated with medetomidine, i.v. (750 micrograms/m2 of body surface area) or i.m. (1,000 micrograms/m2) or with xylazine, i.v. (1.1 mg/kg 10.5 mg/lb] of body weight) or i.m. (2.2 mg/kg [1 mg/lb]). Sedative effects were measured by scoring posture and response to noise. Durations of effects were determined by measuring time intervals between drug administration and changes in posture. Analgesic effects were measured by determining toe-pinch pressure needed to elicit a withdrawal response. Clinicians rated sedative and analgesic effects and ease with which diagnostic or therapeutic procedures could be performed. RESULTS: Posture and response to noise scores were significantly higher for dogs given medetomidine, i.m., than for dogs given xylazine, i.m., and for dogs given medetomidine, i.v., than for dogs given xylazine, i.v. Time to regaining sternal recumbency and time to regaining ability to stand were longest after i.m. administration of medetomidine. Toe-pinch pressures were not significantly different among groups. Clinicians rated overall analgesic and sedative effects as excellent significantly more often after administration of medetomidine than after administration of xylazine. Prevalence of adverse effects did not differ among groups. CLINICAL IMPLICATIONS: Medetomidine and xylazine, at doses tested, were effective and safe, but results of subjective measurements indicated that medetomidine provided better sedation and analgesia than did xylazine. Specific alpha 2-adrenergic antagonists (atipamezole, yohimbine) are available for control of adverse cardiovascular effects.

Analgesics, Non-Narcotic↗

A new family of oligosaccharides from the xyloglucan of Hymenaea courbaril L. (Leguminosae) cotyledons.

The xyloglucan from cotyledons of Hymenaea courbaril was hydrolysed with endo-(1,4)-beta-D-glucanase (cellulase) and analysed by TLC and HPAEC. The limit digest was different from those obtained from xyloglucans of Tamarindus indica and Copaifera langsdorffii. On treatment with nasturtium beta-galactosidase, two main oligosaccharides were detected by TLC and HPAEC. Using a process of enzymatic sequencing involving alternate treatments with a pure xyloglucan oligosaccharide-specific alpha-xylosidase, and a pure beta-glucosidase, both from nasturtium, their structures were deduced to be XXXG and a new oligosaccharide XXXXG. These structures were confirmed by 1H NMR. The relative proportions of XXXG and XXXXG indicate that approximately half of the subunits in Hymenaea xyloglucan are based on the new oligosaccharides. In the native polymer the XXXXG subunits are likely to carry galactosyl substituents in varying proportions, since cellulase hydrolysates contained many bands which were converted to XXXXG on hydrolysis with nasturtium beta-galactosidase. Although no comparative studies on the physico-chemical properties of Hymenaea courbaril xyloglucan have yet been performed, our results indicate that this polymer is less interactive with iodine when compared with T. indica and C. langsdorffii xyloglucans, suggesting that changes in conformation may occur due to the presence of XXXXG.

Chromatography, Thin Layer↗

Evaluation of hip stability after simulated transverse acetabular fractures.

One of the major goals in managing acetabular fractures is the prevention of posttraumatic arthrosis. Unreduced fractures involving the weightbearing portion of the acetabulum may lead to posttraumatic arthrosis, whereas fractures outside this area portend a better prognosis. The purpose of this study was to help distinguish among fractures that require operative reduction, those that can be treated with traction, and those that require even less aggressive treatment. A model was developed to test hip stability after simulated transverse acetabular fractures. The results from this investigation suggest that transverse fractures with a roof arc angle of 90 degrees do not affect the weightbearing portion of the acetabulum. Fractures with a roof arc angle of 60 degrees begin to infringe on the weightbearing area, and those with roof arc angles of less than 60 degrees are clearly in the weightbearing region. Hip stability was significantly affected by the roof are angle and by the interaction of the roof arc angle and the angle of hip abduction or adduction. The data from the current study suggest that the area of the acetabulum considered to be weightbearing in transverse acetabular fractures may be more expansive than previously thought. The model developed may be used to investigate anterior and posterior column fractures.

Acetabulum↗

Regional odontodysplasia: report of four cases.

Four cases of regional odontodysplasia are described. Clinically erupted teeth appear hypoplastic and are often mobile. The radiographic appearance has given rise to the term 'ghost teeth' and the cases presented demonstrate this with short roots which are less well calcified than normal teeth. Clinical and radiographic findings showed that this condition affects only one side of the jaw, but can be seen in any part of the upper or lower jaws. This article represents cases in different parts of the mouth with varying degrees of involvement.

Alveolar Process↗

A new polysaccharide from a traditional Nigerian plant food: Detarium senegalense Gmelin.

The seed flour of an African leguminous plant, Detarium senegalense Gmelin, is used traditionally in Nigeria as a thickening agent in foods. Recent studies have shown that the detarium seed contains a large amount of water-soluble, non-starch polysaccharide (s-NSP), which suggests it has important nutritional properties. The aims of the present study were to characterise the structure and solution properties of purified s-NSP. The main monosaccharide residues of the extracted s-NSP were glucose, xylose, and galactose in the ratio of 1.39:1.00:0.52, suggesting structural similarity to the xyloglucan group of cell wall storage polysaccharides. This was confirmed by comparing the oligosaccharides released on endo-(1 --> 4)-beta-D-glucanase digestion with those obtained from tamarind seed xyloglucan. The intrinsic viscosity [eta] of a sample of the detarium polysaccharide was found to be 8.9 dl/g, indicating that the sample was of high molecular weight, a result confirmed by light scattering. Histochemical examination of detarium seed using bright field and epifluorescence microscopy showed the presence of xyloglucan in highly thickened cell walls, which were particularly prominent at the cell junctions.

Carbohydrate Sequence↗

Substrate subsite recognition of the xyloglucan endo-transglycosylase or xyloglucan-specific endo-(1-->4)-beta-D-glucanase from the cotyledons of germinated nasturtium (Tropaeolum majus L.) seeds.

We have investigated the substrate subsite recognition requirement of the xyloglucan endo-transglycosylase/xyloglucan-specific endo-(1-->4)-beta-D-glucanase (NXET) from the cotyledons of nasturtium seedlings. Seed xyloglucans are composed almost entirely of the Glc4 subunits XXXG, XLXG, XXLG and XLLG, where G represents an unsubstituted glucose residue, X a xylose-substituted glucose residue and L a galactosyl-xylose-substituted glucose residue. Thus in the xyloglucan sequence shown below, the xylose (Xyl) residues at the backbone glucose (Glc) residues numbered -3, -2, +2 and +3 may be galactose-substituted, and NXET cleaves between the unsubstituted glucose at -1 and the xylose-substituted glucose at +1, which never carries a galactosyl substituent. [formula: see text] We have isolated the xyloglucan oligosaccharides XXXGXXXG and XLLGXLLG from NXET digests of tamarind seed xyloglucan, have modified them enzymatically using a pure xyloglucan oligosaccharide-specific alpha-xylosidase from nasturtium seeds to give GXXGXXXG and GLLGXLLG, and have identified and compared the products of NXET action on XXXGXXXG, GXXGXXXG, XLLGXLLG and GLLGXLLG. We have also compared the molar proportions of XXXG, XLXG, XXLG and XLLG in native tamarind and nasturtium seed xyloglucans with those in NXET digests of these polysaccharides. Using these and existing data we have demonstrated that NXET action does not require xylose-substitution at glucose residues -4, -2, +1 and +3 and that xylose substitution at +2, is a requirement. There may also be a requirement for xylose substitution at -3. We have demonstrated also that galactosyl substitution of a xylose residue at +1 prevents, and at -2 modifies, chain-cleavage. A partial model for the minimum substrate binding requirement of NXET is proposed.

Binding Sites↗

Biosynthesis of (1,3)(1,4)-beta-glucan and (1,3)-beta-glucan in barley (Hordeum vulgare L.). Properties of the membrane-bound glucan synthases.

Mixed membrane preparations from the coleoptiles and first leaves of young barley (Hordeum vulgare L. cv. Triumph) plants catalysed the synthesis of 55% methanol-insoluble labelled material from UDP-[U-14C]glucose, the main components of which were identified as (1,3)(1,4)-beta- and (1,3)-beta-D-glucans. The membrane preparations also catalysed the transformation of UDP-glucose into labelled low-molecular-weight products, mainly glucose (by phosphatase action), glucose-1-phosphate (by phosphodiesterase action) and glyco(phospho)lipids (by glycosyltransferase action). The formation of (1,3)(1,4)-beta-glucans, (1,3)-beta-glucans, and the other reactions competing for UDP-glucose, were monitored simultaneously and quantitatively by a novel procedure based on enzymatic analysis, thin-layer chromatography and digital autoradiography. Thus it was possible (i) to optimise conditions to obtain (1,3)(1,4)-beta-glucan synthesis or (1,3)-beta-glucan synthesis in isolation, and (ii) to study the influence of temperature, pH, cofactors, substrate concentration etc. on the (1,3)(1,4)- and (1,3)-beta-glucan synthesis reactions even when both occurred together. The synthesis of both beta-glucans was optimal at 20 degrees C. In Tris-HCl buffer, the pH optima for (1,3)(1,4)-beta-glucan synthesis and (1,3)-beta-glucan synthesis were pH 8.5 and pH 7.0, respectively. Both glucan-synthesis reactions required Mg2+: (1,3)-beta-glucan synthesis was optimal at 2 mM, whereas (1,3)(1,4)-beta-glucan synthesis continued to increase up to 200 mM Mg2+, when the ion was supplied as the sulphate. (1,3)-beta-Glucan synthesis was Ca2+ dependent and this dependence could be abolished by proteinase treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Conformation↗

Rate of glucose entry into hepatic uridine diphosphoglucose by the direct pathway in fasted and fed states in normal humans.

We used the glucuronate (GlcUA) probe technique to measure the rate of glucose entry into hepatic uridine diphosphoglucose (UDP-glc) by the direct pathway, to quantify the rate of appearance (Ra) of hepatic UDP-glc, and to calculate hepatic glucose cycling in vivo in normal humans. The direct pathway contribution to UDP-glc as determined by the ratio of [1-d1]-GlcUA to plasma [LD1]-glucose enrichments was minor (15% to 20%) in normal men after an overnight fast. After 9 hours of refeeding with intravenous (IV) glucose or an oral liquid formula meal each at a rate of 7 mg carbohydrate/kg/min, the direct pathway increased to 66.3% +/- 6.7% and 61.6% +/- 6.0% (mean +/- SE), respectively. Plasma glucose concentrations remained below 7.8 mmol/L and could not account for most of the variability in direct pathway contribution. The dilution of labeled [L-D1]-galactose in excreted acetaminophen-GlcUA was used to measure Ra UDP-glc, on the assumption that labeled galactose passes through the liver during its assimilation. Ra UDP-glc was 1.1 +/- 0.1 mg/kg/min after an overnight fast and increased to 2.0 +/- 0.1 with i.v. glucose and 2.6 +/- 0.2 with the oral liquid mixed meal. By combining the fractional glucose contribution with the Ra of hepatic UDP-glc, the rate of direct glucose entry into hepatic UDP-glc was 0.2 mg/kg/min (fasted) and increased to 1.3 to 1.6 (fed). This represented approximately 18% to 21% of systemic glucose disposal or 19% to 23% of the administered carbohydrate load during i.v. or oral refeeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗

In-vitro measurement of apically extruded irrigant in primary molars.

This study investigated the weights of irrigant extruded apically through extracted primary molar teeth. The aim was to compare the weight of canal irrigant (isotonic sodium chloride solution) extruded through the root canal using either a syringe fitted with a 27-gauge needle or an endosonic unit. Root canals were divided randomly into five groups of 15 discrete canals. The area of each apical foramen was recorded prior to the use of the irrigant. For each irrigation technique the maximum depth of penetration of the needle tip/file was either 2-3 mm or 6-7 mm from the apical foramen. In four groups the crowns of the teeth were in a mandibular position, in the fifth group the teeth were inverted to simulate maxillary teeth. The results showed that irrigant was extruded using both methods. There was significantly less extrusion of irrigant when the endosonic unit was used (P<0.01). There was no statistically significant relationship between foramen area and amount of extruded irrigant (P>0.05). There was no significant extrusion of irrigant in teeth with closed apices when either of the two methods was used (P>0.05).

Analysis of Variance↗