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Biomedical subjects

L Nicholson

Publications and source records attributed to L Nicholson.

At least 19 recordsLinked to original sources
PubMed1994

Risk factors in Klippel-Feil syndrome.

STUDY DESIGN: This study kinematically evaluated radiographs of the cervical spine of patients with the Klippel-Feil syndrome in flexion and in extension to determine alterations from normal motion and potential risk. OBJECTIVES: The results in the study group were compared with those of a control group and with published standards for expected motion of the cervical spine. SUMMARY OF BACKGROUND DATA: The body of orthopedic and neurologic literature suggests a significant problem with neurologic deficit in patients with Klippel-Feil syndrome. No previous study has evaluated the kinematics of the cervical spine with a control group of normal individuals and published standards. METHOD: Lateral flexion-extension radiographs of the cervical spine of 111 patients with Klippel-Feil syndrome were kinematically evaluated to determine the motion of each open interspace and to compare motion with that of a control group and published standards. RESULTS: A statistically significant difference of increased motion per open interspaces in the upper cervical segment was noted in individuals with Klippel-Feil syndrome when compared with the control population. Conversely, total motion of the lower cervical segment was significantly decreased in the Klippel-Feil population when compared with normal controls. Lower segment motion per open interspace was not significantly different when the two groups were compared. CONCLUSION: The results of this study suggest that individuals with Klippel-Feil syndrome with hypermobility of the upper cervical segment are at risk for neurologic sequelae, whereas those with alteration in motion of the lower cervical segment are predisposed to degenerative disease.

Adolescent↗
PubMed1994

Phenotypic variability in the Baller-Gerold syndrome: report of a mildly affected patient and review of the literature.

We report a patient with a mild form of the Baller-Gerold syndrome (craniosynostosis-radial aplasia syndrome). The patient, a 3-year 3 month-old boy, has trigonocephaly with bilateral absent radii and thumbs. His growth parameters and psychomotor development have been normal. No visceral anomalies were found. This patient represents a new case of the rare mild form of the syndrome.

Abnormalities, Multiple↗
PubMed1992

[Special considerations relating to class 1 and class 2 removable partial dentures in the mandible].

During the rehabilitation of partially edentulous patients, dentists must try to preserve the health of the remaining oral structures. That is why it is essential to make maximum use of the support areas. With removable class 1 and 2 prostheses (Kennedy-Applegate classification), the remaining teeth and the edentulous areas provide support. While virtually no movement from the teeth is noticeable, the tissues covering the edentulous ridges do move in a variable manner. A unit must therefore be designed and built to protect the remaining teeth as well as the residual ridges. The problem is all the more acute for the mandible, since the compressibility of the tissues of the edentulous ridges and remodeling of the bone are greater. Many approaches and techniques have been described in the dental literature: functional impressions, use of appropriate direct retainers, and relining of units, if necessary.

Alveolar Bone Loss↗
PubMed1992

[Clinical characteristics affecting the need for relining of class 1 and class 2 removable mandibular prostheses].

This study attempts to identify, from a sample of people wearing a class 1 or 2 removable prosthetic device on the lower jaw, the extent of the relining needs for these prostheses and their determining factors. Epidemiological methods were used to solve this problem. The relining needs increase with the amount of time elapsed since the prosthetic device was put in the mouth (p = 0.014). As for the other factors reviewed, i.e. class of device, type of retainers used, and occlusion, the authors have identified trends instead of real risk factors, since the impact of this study was significantly reduced due to the small number of people we were able to recruit. It was not always possible, therefore, to verify the statistical meaning of the associations observed. In clinical practice, the treatment plan should include a periodical evaluation of the relining needs. As it is now impossible to establish the approximate time when a prosthetic device may need relining, patients wearing one should be examined periodically and regularly.

Adult↗
PubMed1991

Schistosoma mansoni tropomyosin: production and purification of the recombinant protein and studies on its immunodiagnostic potential.

A cDNA that encodes Schistosoma mansoni tropomyosin, except for 10 amino acids at the amino terminus, has been cloned into a pOTSNCO plasmid vector. Induced expression resulted in a constant level of recombinant protein production. The recombinant S. mansoni tropomyosin was purified from preparative SDS-PAGE gel and by a combination of 20% ammonium sulfate fractionation and fast protein liquid chromatography-ion-exchange chromatography. The purified recombinant S. mansoni tropomyosin was tested as an immunodiagnostic reagent in Western blot and enzyme-linked immunosorbent assays. Sera from individual patients with chronic S. mansoni infection, but not S. haematobium, S. japonicum, parasitic infections other than schistosomiasis, and without infection reacted with the recombinant tropomyosin. The species specificity of S. mansoni tropomyosin suggests that further study of its potential as an immunodiagnostic reagent is warranted.

Animals↗
PubMed1990

A normal male with an inherited deletion of one exon within the DMD gene.

We describe two brothers with identical inherited deletions of one single exon within the middle of the DMD gene; one brother has Becker muscular dystrophy diagnosed at 11 years of age, whereas the older brother is normal at 18. These results have implications for genetic counselling and prenatal diagnosis in families with Becker muscular dystrophy.

Adolescent↗
PubMed1990

In-vivo anti-reflux and raft properties of alginates.

The comparative efficacy of two alginate-containing anti-reflux preparations (Gaviscon, Algicon) was assessed in a single blind crossover study of 20 patients with gastro-oesophageal reflux disease. The clinical efficacy study was preceded by two studies in healthy volunteers to assess the intragastric effects of Algicon and Gaviscon by pH measurement, endoscopic visualization and gamma scintigraphy. Algicon and Gaviscon were shown to form a raft in the fasting and fed human stomach, with Algicon alone having a potent antacid effect below and within the raft. Both Algicon and Gaviscon liquids significantly reduced the frequency and severity of reflux symptoms from baseline when given at their recommended doses (10 ml and 20 ml four times daily, respectively). There were no significant differences between Algicon and Gaviscon, although 12 patients preferred Algicon (vs 5 for Gaviscon) for control of reflux symptoms. It was concluded that both Algicon and Gaviscon were effective for the symptomatic control of gastro-oesophageal reflux disease.

Adult↗
PubMed1988

Periventricular and subcortical hyperintensities on magnetic resonance imaging. 'Rims, caps, and unidentified bright objects'.

Magnetic resonance imaging hyper-intensities were classified as periventricular rim, caps, and unidentified bright objects (UBOs). These were quantitated in 100 acute stroke and 23 hemorrhage patients and 59 control subjects selected from 590 consecutive scans. The rims, caps, and ventricular size were rated on a scale from 0 to 3 for severity, and the UBOs were counted. The results indicated that the rim is also frequent in control subjects and increases with age. Unidentified bright objects, caps, and severe rims usually signify pathology, occurring much more frequently in patients with strokes and hemorrhages than in control subjects. Hypertension is a significant risk factor in UBOs and caps, but in rims, the incidence of diabetes is higher. The clinical and pathologic significance of these hyperintensities and their relationship to Binswanger's disease, lacunar state, and "état criblé" is discussed.

Acute Disease↗
PubMed1987

The sensitivity and specificity of MRI in stroke.

We compared MRI and CT in a study of 175 patients; 87 infarcts within a week, 40 from 1 to 40 weeks, 25 a year after onset, and 23 hemorrhages, 18 within 2 weeks and 5 in 4 to 8 weeks. Fifty-nine infarcts and eight hemorrhages had sequential scanning. MRI is more sensitive than CT in the early detection of cerebral infarcts. CT is the method of choice to rule out intracerebral bleeding, but MRI is more specific in later stages of hemorrhage. Periventricular hyperintensity is seen more frequently with diabetes than without. Hyperintense white matter patches are often unrelated to clinical events. MRI is useful in following the evolution of strokes and distinguishing acute and chronic infarcts without contrast agents.

Aged↗
PubMed1986

Regulation by calcium of parathyroid hormone mRNA in cultured parathyroid tissue.

We have examined the effect of changes in the concentration of extracellular calcium on parathyroid hormone mRNA in both short-term (hours) and long-term (days) cultures of bovine parathyroid tissue. Using a 32P-labeled PreProPTH cDNA probe, PTH mRNA was measured by gel blot hybridization of total RNA from tissue slices incubated for 4 h in low (0.5 mM) or high (5 mM) calcium concentrations and also by dot blot hybridization of cytoplasmic RNA extracted from aggregates of partially dispersed cells cultured up to 72 h in low (0.4 mM), normal (1 mM), or high (3 mM) calcium concentrations. PTH mRNA was unchanged over 4 h while high calcium had suppressed PTH secretion. However PTH mRNA did respond during long-term culture. By 24 h in high calcium there was a 50% suppression which was maintained for a further 48 h. PTH mRNA in normal calcium remained unchanged over 72 h while in low calcium it had increased slightly by 48 h. In contrast to the effect seen in cultured bovine parathyroid cells, PTH mRNA in human parathyroid adenoma cells cultured for 48 h in high calcium was decreased by only 10%.

Adenoma↗
PubMed1986

Vitamin D-dependent rickets type II: extreme end organ resistance to 1,25-dihydroxy vitamin D3 in a patient without alopecia.

Vitamin D-dependent rickets type II (VDDR II) is a rare syndrome resulting in severe rickets and is resistant to treatment with vitamin D and its derivatives. Patient with this disease, who are frequently the children of consanguinous marriages, present with elevated circulating concentrations of 1,25-dihydroxy vitamin D, the active metabolite of vitamin D, and in vitro studies have indicated a failure of intracellular binding of the hormone. Alopecia has been noted in many of these patients and it has been suggested that this feature may indicate a more marked resistance to treatment. However we describe a 3-year-old boy with this disease who, although having normal hair growth, displayed extreme resistance to treatment with active vitamin D metabolites. In vitro studies of skin fibroblasts disclosed not only an absence of hormone binding or 1,25(OH)2D3-induced 24-hydroxylase activity but reduced metabolism of 1,25(OH)2D3 itself. In this child, treatment with exogenous 1,25-dihydroxy vitamin D3 at doses of up to 24 micrograms/day, which increased the circulating concentration of the metabolite to greater than 100 times the normal adult mean, failed to alleviate his condition and he died at the age of 39 months. This would therefore suggest that absence of alopecia, in this condition, cannot be regarded as a constant predictive sign of a lesser resistance and of responsiveness to Vitamin D treatment.

Calcitriol↗