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Biomedical subjects

M Oliver

Publications and source records attributed to M Oliver.

At least 37 records · Page 2Linked to original sources
PubMed2000

Off-road machine controls: investigating the risk of carpal tunnel syndrome.

Occupationally induced hand and wrist repetitive strain injuries (RSI) such as carpal tunnel syndrome (CTS) are a growing problem in North America. The purpose of this investigation was to apply a modification of the wrist flexion/ extension models of Armstrong and Chaffin (1978, 1979) to determine if joystick controller use in off-road machines could contribute to the development of CTS. A construction equipment cab in the laboratory was instrumented to allow force, displacement and angle measurements from 10 operators while they completed an approximately 30-min joystick motion protocol. The investigation revealed that both the external fingertip and predicted internal wrist forces resulting from the use of these joysticks were very low, indicating that the CTS risk associated with this factor was slight. However, the results also indicated that, particularly for the 'forward' and 'left' right side motions and for all left side motions, force was exerted by other portions of the fingers and hand, thereby under-predicting the tendon tension and internal wrist forces. Wrist angles observed were highest for motions that moved the joysticks to the sides rather than front to back. Thus, the 'right' and 'left' motions for both hands posed a higher risk for CTS development. When the right hand moved into the 'right' position and the left hand moved into the 'left' position, the wrist went into extension in both cases. Results indicate that neither learning nor fatigue affected the results.

Analysis of Variance↗
PubMed2000

Kikuchi-Fujimoto necrotizing lymphadenitis associated with cutaneous lupus erythematosus: a case report.

Histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto disease is a rare entity, and even more rarely, it is associated with other diseases. In a few cases, the condition is associated with cutaneous lupus erythematosus (CLE). Histiocytic necrotizing lymphadenitis predominantly affects young women, who present with solitary or multiple cervical lymphadenopathy accompanied by symptoms such as fever, weight loss, sweating, or, in exceptional cases, hepatosplenomegaly. Laboratory examinations show normal or nonspecific results. The disease is of unknown origin, although a viral origin has been suggested, with the suspected agents including Epstein-Barr virus, herpesvirus type 6, and cytomegalovirus (CMV). Although the first and most of the more recent cases have been reported in Oriental patients, the disease has a wide geographic distribution. The clinical evolution is favorable, with spontaneous remission in less than 4 months in almost all cases. We present a case of a 37-year-old woman from Peru who presented with cervical adenopathies on two occasions. Biopsy of a lymph node revealed a histopathologic picture compatible with Kikuchi-Fujimoto histiocytic necrotizing lymphadenitis. The adenopathy disappeared in a few months. A year later, she presented with a maculopapular rash in the nasal and malar regions. The results of the skin biopsy and immunofluorescence examination were compatible with chronic CLE. The results of the serology testing for CMV were positive. Treatment with chloroquine was initiated, with almost complete recovery by 5 months. No manifestations of systemic lupus erythematosus have occurred since. The epidemiologic, clinical, and anatomopathologic aspects as well as the differential diagnosis of this entity are reviewed.

Adult↗
PubMed2000

Simple sequence repeats in Cucumis mapping and map merging.

Thirty-four polymorphic simple-sequence repeats (SSRs) were evaluated for length polymorphism in melon (Cucumis melo L.) and cucumber (Cucumis sativus L.). SSR markers were located on three melon maps (18 on the map of 'Vedrantais' and PI 161375, 23 on the map of 'Piel de Sapo' and PI 161375, and 16 on the map of PI 414723 and 'Dulce'). In addition, 14 of the markers were located on the cucumber map of GY14 and PI 183967. SSRs proved to be randomly distributed throughout the melon and cucumber genomes. Mapping of the SSRs in the different maps led to the cross-identification of seven linkage groups in all melon maps. In addition, nine SSRs were common to both melon and cucumber maps. The potential of SSR markers as anchor points for melon-map merging and for comparative mapping with cucumber was demonstrated.

Chromosome Mapping↗
PubMed1999

Folate-homocysteine interrelations: potential new markers of folate status.

We report a transient drop in plasma Hcy and Cys following a single oral dose of PteGlu. The thiol change was concomitant with both the peak plasma 5CH3H4PteGlu1 level (by HPLC) and the maximum plasma Lactobacillus casei activity which reflects absorption of unmodified PteGlu. The significant reciprocal association of Hcy with radioassay RBC folate (r = -0.28, 99% CI -0.48, -0.05, P = 0.0016), serum folate (r = -0.37, 99% CI -0.56, -16, P = 0.0001), and vitamin B12 (r = -0.42, 99% CI -0.59, -21, P = 0.0001) is shown and reflects the long-term nutritional effect of B vitamins on this important, potentially atherogenic thiol. These are now well-established associations. We extend the potential for investigation of folate metabolism in health and disease by evaluating a range of new folate indices which are based on erythrocyte coenzymes. These have been looked at independently and in association with established parameters. Erythrocyte methylfolates (mono- to hexaglutamate-5CH3H4PteGlu1-6), formylfolates (tri- to pentaglutamate-5CHOH4PteGlu3-5),formiminotetrahydrofolate (formiminoH4PteGlu1), unsubstituted tetrahydrofolate (H4PteGlu1), andpara-aminobenzoylglutamate (P-ABG) have been measured by HPLC with fluorescence detection. A positive linear association exists between (i) H4PteGlu1 and radioassay RBC folate (r = 0.50, 99% CI 0. 07, 0.77, P = 0.0036), and (ii) H4PteGlu1 and tetraglutamates of both formyl- and methylfolate (r = 0.52, 99% CI 0.10, 0.78, P = 0. 0022, and r = 0.56, 99% CI 0.15, 0.80, P = 0.0009, respectively). Since, in addition, a reciprocal linear association exists between Hcy and tetraglutamyl formylfolate (r = -0.41, 99% CI -0.73, 0.05, P = 0.0206), erythrocyte tetraglutamates may be a good reflection of the bodies' active coenzyme pools. Pentaglutamyl formylfolate, the longest oligo-gamma-glutamyl chain form of this coenzyme may be a good indicator of folate depletion. The abundance of this coenzyme both increases with increasing Hcy (r = 0.55, 99% CI 0.13, 0.80, P = 0.0014) and increases as H4PteGlu1, the principle folate congener, decreases (r = -0.59, 99% CI -0.82, -0.20, P = 0.0004). Furthermore, the apparent equilibrium between substrate (5CH3H4PteGlu1) and product (H4PteGlu1) of methionine synthase is significantly associated with the abundance of 5CHOH4PteGlu5 (r = -0.53, 99% CI -0. 79, -0.11, P = 0.0018). This suggests that low methionine synthase activity for whatever reason (metabolic or dietary) may lead to an increase in the relative abundance of 5CHOH4PteGlu5. Like 5CHOH4PteGlu5, evidence is given that 5CH3H4PteGlu6, the longest oligo-gamma-glutamyl chain form of this particular coenzyme pool, may also be a good indicator of folate depletion. This is shown by a change in the relative proportion of erythrocyte methylfolate polyglutamates following supplementation with 400 microg/day PteGlu. Short-chain polyglutamates of methylfolate (5CH3H4PteGlu1--> 5CH3H4PteGlu4) increase in proportion to the total methylfolate pool, while long-chain polyglutamates of methylfolate (5CH3H4PteGlu5 and particularly 5CH3H4PteGlu6) decrease in their relative abundance.

Adult↗
PubMed1999

Slow-transit constipation in childhood.

BACKGROUND/PURPOSE: Intestinal neuronal dysplasia (IND) as a cause for severe chronic constipation remains controversial. The authors have identified a deficiency of substance P (SP) immunoreactivity in the colonic nerve fibres of some children with severe constipation, and aim to correlate this with clinical features and transit studies. METHODS: Over 100 children with intractable constipation with or without soiling have been assessed by clinical questionnaire, nuclear transit study, and laparoscopic seromuscular biopsy of the colon labelled with antibodies to SP and vasoactive intestinal peptide (VIP) using immunofluorescence. RESULTS: More than 30% of children had delayed passage of meconium, and symptoms of constipation appeared by the age of 1 year in 63%. More than 80% had significant delay in colonic transit, and of these, about 80% had reduced SP immunoreactivity in the axons of the colonic circular muscle. A further 6% had heterotopic ganglion cells or hypoplastic ganglia on routine histology. CONCLUSIONS: In children with intractable constipation, features of early onset and delayed colonic transit correlated with deficiency of SP in myenteric axons. The authors propose that deficient SP immunoreactivity may be used as a histological marker for severe constipation. Defective excitatory neuromuscular transmission may be the cause of slow colonic transit.

Adolescent↗
PubMed1999

Serum anion gap in the differential diagnosis of metabolic acidosis in critically ill newborns.

OBJECTIVES: To determine in critically ill newborn infants (1) the range of the serum anion gap without metabolic acidosis and (2) whether the serum anion gap can be used to distinguish newborns with lactic acidosis from those with hyperchloremic metabolic acidosis. STUDY DESIGN: Umbilical arterial blood gases and serum electrolyte and lactate concentrations were measured simultaneously in 210 samples from 63 infants over the first week of life. Metabolic acidosis was defined as a blood base deficit (BD) >4 mmol/L. The anion gap was calculated as [Na(+)] - [C1(-)] - [TCO (2)]. Lactic acidosis was defined as a serum lactate concentration >2 SD above the mean serum lactate concentration in samples without metabolic acidosis. RESULTS: In 89 blood samples with BD <4 mmol/L, serum lactate concentration decreased with postnatal age (r = 0.51). The upper limit of serum lactate concentration was 3.8 mmol/L at less than 48 hours, 2.4 mmol/L between 48 and 96 hours, and 1.5 mmol/L for infants greater than 96 hours of age. The mean serum anion gap +/- 2 SD in 174 samples without lactic acidosis was 8 +/- 4 mmol/L; in 36 samples with lactic acidosis it was 16 +/- 9 mmol/L (P <.0001). Serum anion gap and lactate concentration were poorly correlated for samples without lactic acidosis (r = 0.04) but highly correlated in those with lactic acidosis (r = 0.81, P <.0001). None of the 85 samples with metabolic acidosis but without lactic acidosis had an anion gap >16 mmol/L; only 4 of 36 samples with lactic acidosis had an anion gap <8 meq/L. However, 25 of 36 samples with lactic acidosis had serum anion gaps of 8 to 16 mmol/L. CONCLUSION: In the presence of metabolic acidosis, a serum anion gap >16 mmol/L is highly predictive of lactic acidosis; a serum anion gap <8 is highly predictive of the absence of lactic acidosis; an anion gap = 8 - 16 mmol/L has no use in the differential diagnosis of metabolic acidosis in the critically ill newborn.

Acid-Base Equilibrium↗
PubMed1999

Predictive value of family data for the management of infantile bilateral partial cataract.

PURPOSE: To examine the data on outcome of surgery performed over a wide age range in members of a family affected by familial infantile bilateral partial cataract, with the purpose of assessing their predictive value concerning the timing of surgery. METHODS: A retrospective clinical study was carried out of a family with dominant inheritance of familial infantile bilateral partial cataract. The family spanned four generations and consisted of 53 members, 31 of whom were examined in our department. Of these, 18 were affected. Cataract surgery was performed in 26 eyes of 15 patients, whose ages ranged from 6 to 58 years at the time of operation. As the surgical procedures spanned the years from 1978 to 1996, different techniques were used. RESULTS: In 24 eyes (92%) the post-operative visual acuity was 6/9 or better. One eye achieved 6/12 and another 6/15. CONCLUSIONS: In this particular family there was no relationship between the post-operative visual acuity and the age at which surgery was performed. In deciding when to operate on family members with infantile bilateral partial cataract with similar morphology, in addition to the commonly used criteria the family data should also be taken into account. In infants and young children, delaying surgery may allow better development of visual acuity aided by accommodation, stabilisation of binocularity and more precise determination of the power of an intraocular lens. Success of very early surgery in such cases may not be attributable to the timing of the operation.

Adolescent↗
PubMed1999

Rigid occipitocervical fusion.

OBJECT: Despite 50 years of neurosurgical experience, occipitocervical fusion continues to present a technical challenge to the surgeon. Traditional nonrigid techniques applied in the occiput and cervical spine often fail secondary to postsurgical cranial settling or rotational deformity. Unlike widely used nonrigid and semirigid techniques, rigid fixation of the craniocervical junction should allow correction of deformity in any plane, provide immediate stability without need for external orthosis, and prevent cranial settling. METHOD: Since 1992, the senior author (D.W.C.) has used a rigid plate and screw fixation system for occipitocervical fusions. The technique proved to be more difficult than expected, and the procedure has evolved as experience was gained. The authors present a series of 24 patients and a technique that now involves the use of a custom-designed T-plate that is attached to the midline occipital "keel" at one end and to the spine at the other end by means of screw-fixed plates. CONCLUSIONS: Although it is still evolving, the current technique for obtaining rigid occipitocervical fixation allows for immediate rigidity and stability of the spine without the use of an external orthosis (that is, in the absence of osteoporosis), may be extended to any level of the spine, may be used in the absence of posterior elements, prevents postsurgical cranial settling and restenosis, facilitates reduction of the spinal deformity in any plane, and sometimes eliminates the need for an anterior (transoral) decompressive procedure.

Adult↗
PubMed1998

Long-term effect of hypermetropic anisometropia on the visual acuity of treated amblyopic eyes.

AIM: To evaluate the effect of the extent of hypermetropic anisometropia on the long term visual acuity results in amblyopic eyes following their treatment by occlusion. METHODS: The visual acuity of 86 patients, who had been treated for unilateral amblyopia by occlusion of the fellow eye and followed up at least to the age of 9 years, was examined 6.4 years, on average, after cessation of treatment. Patients were divided into two groups--those with a small amount of hypermetropic anisometropia, where the spherical equivalent difference between the eyes ranged between 0 and +1.50 dioptres, and those with a large amount of hypermetropic anisometropia, where the difference was +1.75 dioptres or greater. RESULTS: Deterioration of visual acuity after cessation of occlusion treatment occurred in 51% of the patients in the group with a small amount of anisometropia and in 75% of the patients in the group with a large amount. At cessation of treatment, the average visual acuity in both groups was 20/40+. At the long term follow up examination, however, the average visual acuity was 20/40- and 20/70, respectively. This difference was statistically significant. CONCLUSIONS: Hypermetropic anisometropia greater than 1.50 dioptres appears to be a risk factor for deterioration of visual acuity in the long term, following treatment of amblyopic eyes by occlusion of the fellow eye.

Adolescent↗
PubMed1998

The course of age-related macular degeneration following bilateral cataract surgery.

BACKGROUND AND OBJECTIVE: Progression of age-related macular degeneration (AMD) following cataract surgery has been described. The aim of this study was to investigate whether an uneventful postoperative maculopathic course in one eye (the first eye) may predict a similar prognosis for the fellow eye (the second eye). PATIENTS AND METHODS: Thirty-three patients with bilateral, similar, early AMD (defined by the presence of drusen and/or pigmentary abnormalities on fundal examinations and by the absence of late leakage as documented by fluorescein angiography) who had undergone unilateral cataract surgery, had had a stable postoperative maculopathic course following the first operation, and were scheduled for cataract surgery in the second eye were prospectively observed for at least 1 year after the second operation. The course of maculopathy of the second eye was compared with that of the first eye during the follow-up period of the second eye. RESULTS: A total of 9 of the second eyes (27.2%) showed progression to wet AMD. Of these, 1 patient (3%) had progression in both eyes and 8 patients (24.2%) had progression in the second eye only. The conditions of 2 of the first operated on eyes (6.1%) deteriorated (P < .05). Hypertension (P < .05), soft drusen (P < .01), and Nd:YAG laser capsulotomy (P < .05) were risk factors for development of wet AMD. CONCLUSION: In this study, 24.2% of the patients with early AMD who underwent bilateral cataract surgery and had an uneventful maculopathic course in the first eye had wet AMD in the second eye. Thus, patients with early AMD and soft drusen undergoing bilateral cataract surgery should be monitored for early detection of progression of maculopathy. Further prospective studies are needed to determine the course of maculopathy following cataract surgery.

Aged↗
PubMed1997

MDs remain sceptical as chelation therapy goes mainstream in Saskatchewan.

The College of Physicians and Surgeons of Saskatchewan recently agreed to allow physicians to administer chelation therapy. Supporters, relying on anecdotal evidence, say it works wonders in overcoming heart disease, but many physicians remain profoundly sceptical. In Saskatchewan, the college decision has proved popular with patients but has drawn an angry reaction from doctors.

Aged↗
PubMed1997

Risk of neural tube defect-affected pregnancy is associated with a block in maternal one-carbon metabolism at the level of N-5-methyltetrahydrofolate:homocysteine methyltransferase.

The disposition of whole blood mono-to hexaglutamyl methylfolate and plasma homocysteine (HCY) was used to evaluate potential lesion sites in one-carbon metabolism which could be responsible for neural tube defect(NTD)-affected pregnancies. An isocratic high-performance liquid chromatographic system (HPLC) with photodiode array detection was used to quantify and speciate whole-blood methylfolate into mono-, di-, tri-, tetra-, penta-, and hexaglutamate forms. This technique was also used with off-line radioassay to identify nonmethyl whole-blood folates. Isocratic HPLC with fluorescence detection was used to quantify SBDF derivatized homocysteine in plasma. The study investigated blood from 11 women who had experienced a previous NTD-affected pregnancy and 11 controls of similar age and social class. No subjects were pregnant. HCY levels were significantly higher in NTD subjects (P = 0.0486, 95% CI-2.799,0.001 using the Mann-Whitney test), as was the ratio of known intracellular (tri-to hexaglutamyl) methylfolate compared to extracellular (mono- and diglutamyl) methylfolate (P = 0.0062 95% CI-0.543, 3.862 using the Mann-Whitney test). Vitamin B12, red cell folate, circulating total methylfolate, and circulating mono-to hexaglutamyl methylfolates showed no difference between population groups. The disposition between individual and cumulative glutamate chain lengths of methylfolate showed significant trends which differed between population groups: (i) total blood methylfolate (Glu1-6) appears to be utilized by N-5-methyltetrahydrofolate:homocysteine methyltransferase (MS) in control blood but not NTD blood, where it appears to accumulate following a 45-min incubation; (ii) whole-blood hexaglutamyl methylfolate (5CH3-H4PteGlus) becomes a larger proportion of the total blood methylfolate in NTD than in control populations; and (iii) the intermediate glutamate chains of methylfolate (Glu1-5) remain relatively constant as 5CH3-H4PteGlu6 accumulates in NTD but appear to increase linearly with 5CH3-H4PteGlu6 in controls. The significant elevation of HCY in the NTD population is associated with the increasing proportion of 5CH3-H4PteGlu6 relative to the total methylfolate, since, when corrected for HCY level, the proportion of 5CH3-H4PteGlus to total methylfolate is similar in NTD and control populations. These trends are consistent with a defect at the level of vitamin B12 dependent MS which "traps" folate at the 5CH3-H4PteGlus level.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1997

Submandibular gland peptide-T (SGP-T) inhibits intestinal anaphylaxis.

A novel peptide, submandibular gland peptide-T (SGP-T), which reduces allergen-induced hypotension, was examined for effects on intestinal anaphylaxis. Hooded-Lister rats were sensitized to egg albumin and prepared for the measurement of in vivo myoelectric activity of the jejunum. The disruption of migrating myoelectric complexes (MMCs) that occurs upon intraluminal, duodenal challenge with antigen of sensitized rats was inhibited by 75% upon intravenous treatment with 100 micrograms/kg of SGP-T. In addition, SGP-T reduced the number of rats experiencing anaphylactic diarrhea and disrupted MMCs, but the peptide did not alter antigen-provoked release of rat mast cell protease II. The mechanism of action of SGP-T remains to be determined, but it apparently does not act directly on mast cells to exert its antianaphylactic action. These results emphasize that modulation of immediate hypersensitivity reactions is only one of several gastrointestinal activities that are affected by growth factors and peptides released from salivary glands.

Anaphylaxis↗
PubMed1997

Development of exudative age-related macular degeneration after cataract surgery.

The macular status of patients with findings consistent with early dry age-related macular degeneration (AMD) who underwent an extracapsular cataract extraction with intraocular lens implantation was evaluated by fundoscopy and fluorescein angiography pre-operatively and during the first post-operative year. Five patients who developed the exudative form of AMD, and who represent the problems arising when treating patients with AMD and cataract, are described. Patients who received laser photocoagulation responded with recurrent choroidal neovascularisation. We suggest that patients with signs of age-related changes scheduled for cataract surgery should undergo a thorough pre- and post-operative assessment of their retinal status.

Aged↗