Biomedical subjects

L Robson

Publications and source records attributed to L Robson.

At least 55 records · Page 3Linked to original sources

PubMed1999

Duplication within chromosome 5q characterized by fluorescence in situ hybridization.

We present a 16-month-old boy with developmental delay, minor anomalies, small penis, and lymphedema of the upper limbs. Routine cytogenetic analysis suspected a duplication of 5q. Fluorescent in situ hybridization (FISH) with a cosmid probe (MCC at the 5q22 APC region) showed tandemly duplicated fluorescent signals on one of chromosomes 5, whereas FISH with three YAC probes (TYAC12 at 5q35, HTY3182 at 5q34, and TYAC139 at 5q31) did not give duplicated signals. These findings indicate a duplication of 5q22 band in one chromosome 5. The boy we describe here is the first case of a pure partial duplication of 5q to be proven by FISH techniques. A review of previously reported cases of putative partial 5q duplication showed no consistent phenotype.

Abnormalities, Multiple↗

PubMed1999

The economic consequences of smoking in Ontario.

Smoking causes health and social problems such as sickness, death, fire, injury, pain and suffering. This paper provides an estimate of the economic burden imposed by the adverse health and social consequences of smoking in Ontario in 1992. The cost-of-illness method, in particular, the human-capital approach is used to estimate the prevalence-based economic costs of smoking. The direct and indirect components of smoking-related costs are estimated and the total cost in Ontario is US$2.91 billion. Associated with these economic costs are health-related harms: 69,318 hospital separations; 1,007,647 days stay in hospitals; 11,648 deaths resulting in more than 171,443 person-years lost.

Adolescent↗

PubMed1999

Novel chromosome 16 abnormality--der(16)del(16) (q13)t(16;21)(p11.2;q22)--associated with acute myeloid leukemia.

Inversion of chromosome 16 is a common feature of acute myeloid leukemia (AML) M4, while t(16;21), although also associated with AML, appears to be a separate entity. We present a patient with myelodysplastic syndrome (MDS) who transformed to AML-M1. The karyotype was normal at diagnosis; at 15 months, hematological evidence of transformation was present, and repeat cytogenetics showed a novel rearrangement of one chromosome 16. Two breaks had occurred; one in the short arm at 16p11, with translocation of the segment distal to this onto chromosome 21q, and the other in the long arm at 16q22 with subsequent deletion of the segment from 16q22-->qter. Fluorescence in situ hybridization (FISH) confirmed the abnormalities detected by cytogenetics and excluded involvement of the AML1 gene on 21q22. While the 16q22 breakpoint was at the usual site for the inv(16), the 16p11 was not. The patient is more characteristic of t(16;21) than inv(16), and adds to the spectrum of chromosome 16 abnormalities in AML.

Aged↗

PubMed1999

Sonic hedgehog (SHH) specifies muscle pattern at tissue and cellular chick level, in the chick limb bud.

Development of the musculature in chick limbs involves tissue and cellular patterning. Patterning at the tissue level leads to the precise arrangement of specific muscles; at the cellular level patterning gives rise to the fibre type diversity in muscles. Although the data suggests that the information controlling muscle patterning is localised within the limb mesenchyme and not in the somitic myogenic precursor cells themselves, the mechanisms underlying muscle organisation have still to be elucidated. The anterior-posterior axis of the limb is specified by a group of cells in the posterior region of the limb mesenchyme, called the zone of polarizing activity (ZPA). When polarizing-region cells are grafted to the anterior margin of the bud, they cause mirror-image digit duplications to be produced. The effect of ZPA grafts can be reproduced by application of retinoic acid (RA) beads and by grafting sonic hedgehog (SHH)-expressing cells to the anterior margin of the limb. Although most previous studies have looked at changes of the skeletal patterning, ZPA and RA also affect muscle patterning. In this report, we investigated the role of SHH in tissue and cellular patterning of forearm wing muscles. Ectopic application of a localised source of SHH to the anterior margin of the wing, leading to complete digit duplication, is able to transform anterior forearm muscles into muscles with a posterior identity. Moreover, the ectopic source of SHH induces a mirror image duplication of the normal posterior muscles fibre types in the new posterior muscles. The reorganisation of the slow fibres can be detected before muscle mass cleavage has started; suggesting that the appropriate fibre type arrangement is in place before the splitting process can be observed.

Animals↗

PubMed1999

Treatment of migraine with pulsing electromagnetic fields: a double-blind, placebo-controlled study.

The effect of exposure to pulsing electromagnetic fields on migraine activity was evaluated by having 42 subjects (34 women and 8 men), who met the International Headache Society's criteria for migraine, participate in a double-blind, placebo-controlled study. Each subject kept a 1-month, pretreatment, baseline log of headache activity prior to being randomized to having either actual or placebo pulsing electromagnetic fields applied to their inner thighs for 1 hour per day, 5 days per week, for 2 weeks. After exposure, all subjects kept the log for at least 1 follow-up month. During the first month of follow-up, 73% of those receiving actual exposure reported decreased headaches (45% good decrease, 14% excellent decrease) compared to half of those receiving the placebo (15% worse, 20% good, 0% excellent). Ten of the 22 subjects who had actual exposure received 2 additional weeks of actual exposure after their initial 1-month follow-up. All showed decreased headache activity (50% good, 38% excellent). Thirteen subjects from the actual exposure group elected not to receive additional exposure. Twelve of them showed decreased headache activity by the second month (29% good, 43% excellent). Eight of the subjects in the placebo group elected to receive 2 weeks of actual exposure after the initial 1-month follow-up with 75% showing decreased headache activity (38% good, 38% excellent). In conclusion, exposure of the inner thighs to pulsing electromagnetic fields for at least 3 weeks is an effective, short-term intervention for migraine, but not tension headaches.

Adult↗

PubMed1999

Assessment methods for alcohol consumption, prevalence of high risk drinking and harm: a sensitivity analysis.

BACKGROUND: There are no standardized ways to assess alcohol consumption in epidemiological studies. The main objective of the present study was to compare three widely used methods for assessing alcohol consumption with respect to resulting prevalence estimates for high risk drinking and harm as defined by morbidity and mortality indicators. METHODS: A within-subjects design was used to compare a quantity frequency, a graduated frequency, and a weekly drinking recall measure. Data consisted of a representative sample of 3961 adult residents of the province of Ontario, Canada, who participated in a multi-wave cross-sectional survey between 1990-1994. Cross-tabulation, Spearman correlation, and standard methodologies for prevalence-based cost-of-illness studies were used. RESULTS: The graduated frequency measure consistently yielded higher estimates of the prevalences of high risk drinking and harm. Differences were marked on all indicators, but were most pronounced for harmful drinking as defined by consuming an average of >60 g pure alcohol per day for males, and >40 g per day for females. Prevalence estimates of harmful drinking were almost five times higher for graduated frequency versus weekly drinking measures, and almost three times higher for graduated frequency versus quantity frequency measures. CONCLUSIONS: The characteristics of different measures of alcohol consumption should be considered in future research in epidemiology.

Adult↗

PubMed1999

Morbidity and mortality attributable to alcohol, tobacco, and illicit drug use in Canada.

OBJECTIVES: This study estimated morbidity and mortality attributable to substance abuse in Canada. METHODS: Pooled estimates of relative risk were used to calculate etiologic fractions by age, gender, and province for 91 causes of disease or death attributable to alcohol, tobacco, or illicit drugs. RESULTS: There were 33,498 deaths and 208,095 hospitalizations attributed to tobacco, 6701 deaths and 86,076 hospitalizations due to alcohol, and 732 deaths and 7095 hospitalizations due to illicit drugs in 1992. CONCLUSIONS: Substance abuse exacts a considerable toll on Canadian society in terms of morbidity and mortality, accounting for 21% of deaths, 23% of years of potential life lost, and 8% of hospitalizations.

Adult↗

PubMed1999

The hemodynamic effects of local anesthetic injection into the carotid body during carotid endarterectomy.

Hemodynamic changes consisting of hypertension, hypotension, or bradycardia are commonly seen in patients undergoing carotid endarterectomy. It is a potentially serious clinical problem that may increase mortality rates or incidence of neurologic deficits. The frequency of hemodynamic alterations has been believed to be related to the proximity of the carotid sinus baroreceptor to the endarterectomized region. Consequently, intraoperative or postoperative injection of local anesthetics into the carotid body have been recommended to help offset this compensatory mechanism. However, its effectiveness has not been thoroughly studied. We examined this situation with a prospective, randomized, double-blind clinical study consisting of 99 patients. Xylocaine (short-acting anesthetic), bupivacaine (long-acting anesthetic), or saline (control) was injected into the carotid body intraoperatively. Intraoperative and postoperative hemodynamic changes were then closely monitored and evaluated. We were unable to detect a significant difference in hypotension, hypertension, or bradycardia either during or after surgery. Therefore, on the basis of this study, routine use of local anesthetic injection into the carotid body cannot be recommended.

Aged↗

PubMed1999

Novel translocation t(3;11)(p21;q24) in multiple myeloma characterised by FISH.

We present a 72 year old man with multiple myeloma (MM). Cytogenetic and FISH analysis of bone marrow aspirate showed a novel translocation -der(11)t(3;11)(p21;q24). The unbalanced karyotype led to substantial partial trisomy for chromosome 3p and small partial monosomy 11q. Structural rearrangements of chromosome 3 are uncommon in MM and these are reviewed. The patient died 2 years after the diagnosis of MM was made.

Aged↗

PubMed1998

The role of Ca2+ in volume regulation induced by Na+-coupled alanine uptake in single proximal tubule cells isolated from frog kidney.

1. It has been suggested that epithelial cells maintain cell volume and function, in the face of changes in the rate of transepithelial transport, by activation of volume-regulatory pathways. 2. The aim of the following study was to examine directly the effect of an alteration in Na+-coupled alanine transport on cell length in single proximal tubule cells isolated from frog kidney. 3. An optical technique was used to examine the change in cell length induced by 5 mM L-alanine. 4. On addition of L-alanine to the bath there was an initial increase in cell length to a peak value. This was followed by two types of response. In eighteen out of thirty-one cells a typical volume-regulatory response was observed. The remaining cells showed no volume regulation. 5. Volume regulation was not affected by the removal of extracellular Ca2+. The mean degrees of recovery were 159 +/- 21 % (n = 18) and 144 +/- 18 % (n = 8) in the presence and absence of Ca2+, respectively. 6. Volume regulation was inhibited by depletion of intracellular Ca2+ stores, or in the presence of either Gd3+ or DIDS. The mean degrees of regulation were 55.4 +/- 9.2 % (n = 7), 68.2 +/- 18.8 % (n = 7) and 69.1 +/- 14.3 % (n = 7), respectively. 7. The alanine-induced increases in cell length were both stereospecific and Na+ dependent. 8. The evidence suggests that volume regulation induced by Na+-coupled alanine uptake may be dependent on the release of Ca2+ from intracellular stores. This is in contrast to volume regulation induced by hypotonic shock, which appears to require extracellular Ca2+. Results obtained using a hypotonic shock should, therefore, be viewed with caution.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1998

The economic costs of illicit drug use in Ontario, 1992.

The use of illicit drugs causes health and social problems which imply economic costs to society. This paper uses the cost-of-illness method, in particular, the human-capital approach to estimate the prevalence-based economic costs of illicit drug use in Ontario in 1992. This methodology is consistent with international guidelines formulated at the 1994 International Symposium on Economic and Social Costs of Substance Abuse. The economic cost of illicit drug use is estimated at $489.29 million (Canadian dollars) in 1992. Associated with these costs are health-related harms: 211 deaths, half of which occur before the age of 35; and 20 690 days stay in public hospitals.

Cost of Illness↗

PubMed1998

The economic costs of alcohol abuse in Ontario.

The abuse of alcohol causes health and social problems, such as sickness, death, injury, pain, suffering and crime. These harms impose an economic burden on society. Resources are used or foregone as a consequence of alcohol abuse. This article provides an estimate of the economic cost of alcohol abuse in Ontario in 1992. It uses the cost-of-illness method, in particular, the human-capital approach to estimate the prevalence-based economic costs of alcohol abuse. This methodology is consistent with international guidelines formulated at the 1994 International Symposium on Economic and Social Costs of Substance Abuse. The direct and indirect economic costs of alcohol abuse are identified and estimated. The total economic cost of alcohol abuse, from a societal perspective, is estimated to be US$2261.10 million in Ontario in 1992.

Alcoholism↗

PubMed1998

Evaluation of methylation analysis for diagnostic testing in 258 referrals suspected of Prader-Willi or Angelman syndromes.

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are distinct neurodevelopmental disorders with interrelated genetic mechanisms because genomic imprinting within the chromosome 15q11-13 region affects both the PWS and the AS locus. Methylation analysis is one method of distinguishing between the maternally and paternally inherited chromosome 15. Here we present clinical and molecular data on a large series of 258 referred patients, evaluated with methylation analysis: 115 with suspected PWS and 143 with suspected AS. In these patients, the clinical phenotype was graded into three groups: classical (group 1); not classical but possible (group 2); not classical and unlikely (group 3). For PWS, a fourth group consisted of hypotonic babies. DNA methylation analysis confirmed the diagnosis of PWS in 30 patients (26%) and AS in 28 patients (20%). For 21 PWS patients the mechanism was established: 15 had deletions, 4 had uniparental disomy (UPD) and 2 a presumed imprinting defect. Clinically all those with an abnormal methylation pattern had the classical phenotype and none of those with a normal methylation pattern had classical PWS. For 23 AS patients in whom a mechanism was established, 17 had a deletion, 3 had UPD and 3 had a presumed imprinting defect. There was greater clinical overlap in AS, with 26 classical AS patients having a normal methylation pattern while an abnormal methylation pattern was seen in one patient from group 2. In addition, there were a further 40 patients with a normal methylation pattern in whom AS was still a possible diagnosis. Our conclusion is that methylation analysis provides an excellent screening test for both syndromes, providing approximately 99% diagnosis for PWS and for AS, a 75% diagnostic rate, supplemented for the remaining 25% with an essential basic starting point to further investigations.

Adolescent↗

PubMed1998

The economic costs of alcohol, tobacco and illicit drugs in Canada, 1992.

UNLABELLED: AIMS, DESIGN AND SETTING: The economic costs of alcohol, tobacco and illicit drugs in Canadian society in 1992 are estimated utilizing a cost-of-illness framework and recently developed international guidelines. MEASUREMENTS: For causes of disease or death (using ICD-9 categories), pooled relative risk estimates from meta-analyses are combined with prevalence data by age, gender and province to derive the proportion attributable to alcohol, tobacco and/or illicit drugs. The resulting estimates of attributable deaths and hospitalizations are used to calculate associated health care, law enforcement, productivity and other costs. The results are compared wit other studies, and sensitivity analyses are conducted on alternative measures of alcohol consumption, alternative discount rates for productivity costs and the use of diagnostic-specific hospitalization costs. FINDINGS: The misuse of alcohol, tobacco and illicit drugs cost more than $18.4 billion in Canada in 1992, representing $649 per capita or 2.7% of GDP. Alcohol accounts for approximately $7.52 billion in costs, including $4.14 billion for lost productivity, $1.36 billion for law enforcement and $1.30 billion in direct health care costs. Tobacco accounts for approximately $9.56 billion in costs, including $6.82 billion for lost productivity and $2.68 billion for direct health costs. The economic of illicit drugs are estimated at $1.4 billion. CONCLUSIONS: Substance abuse exacts a considerable toll to Canadian society in terms of illness, injury, death and economic costs.

Alcohol Drinking↗

PubMed1998

A case of monosomy 21 found to be an unbalanced de novo t(5p;21q) by fluorescence in situ hybridization.

A case is presented in which monosomy 21 was detected by routine cytogenetics and fluorescence in situ hybridization (FISH) studies demonstrated an unbalanced translocation t(5;21). The patient was partially monosomic for both 5p and 21q. The phenotype of the infant showed some features of the 5p- (cri-du-chat) syndrome, but there were also features present which were uncharacteristic of this syndrome. The present findings, combined with similar cases reported in the literature, provide further support for a proximal monosomy 21q syndrome.

Chromosome Aberrations↗

PubMed1998

Initial exploration of pulsing electromagnetic fields for treatment of migraine.

Two studies were conducted during which 23 patients with chronic migraine were exposed to pulsing electromagnetic fields over the inner thigh. In an open study, 11 subjects kept a 2-week headache log before and after 2 to 3 weeks of exposure to pulsing electromagnetic fields for 1 hour per day, 5 days per week. The number of headaches per week decreased from 4.03 during the baseline period to 0.43 during the initial 2-week follow-up period and to 0.14 during the extended follow-up which averaged 8.1 months. In a double-blind study, 9 subjects kept a 3-week log of headache activity and were randomly assigned to receive 2 weeks of real or placebo pulsing electromagnetic field exposures as described above. They were subsequently switched to 2 weeks of the other mode, after which they kept a final 3-week log. Three additional subjects in the blind study inadvertently received half-power pulsing electromagnetic field exposures. The 6 subjects exposed to the actual device first showed a change in headache activity from 3.32 per week to 0.58 per week. The 3 subjects exposed to only half the dose showed no change in headache activity. Large controlled studies should be performed to determine whether this intervention is actually effective.

Adult↗

PubMed1998

Normal growth in Angelman syndrome due to paternal UPD.

We describe 2 patients with Angelman syndrome (AS) due to paternal uniparental disomy (UPD). One patient is a female aged 30 years and the other a male aged 4 1/2 years. Both have the characteristic wide mouth and big chin, moderate mental retardation, virtually no speech but some 30 words of sign language and a happy disposition with outbursts of laughter. Ataxia is minimal in both patients, manifesting mainly when they are excited or running. Both patients are tall (height around 90th percentile), have a head circumference around 75th percentile and are overweight (weight over the 97th percentile). These cases add to the knowledge of the possibility of normal or increased growth parameters, particularly weight, in AS when the genetic mechanism is paternal UPD.

Adult↗

PubMed1997

Manifestations in institutionalised adults with Angelman syndrome due to deletion.

Undiagnosed institutionalised patients were reviewed in an attempt to identify those with Angelman syndrome (AS). The aim was to test these patients for deletion of chromosome 15(q11-13) and to describe the adult phenotype. The selection criteria included severe intellectual disability, ataxic or hypermotoric limb movements, lack of speech, a "happy" demeanour, epilepsy, and facial appearance consistent with the diagnosis. Patients were examined, medical records perused, and patients' doctors contacted as required. Genetic tests performed included routine cytogenetics, DNA methylation analysis (with probe PW71B), and fluorescence in situ hybridisation (with probes D15S10, GABRbeta3, or SNRPN). A deletion in the AS region was detected in 11 patients (9 males and 2 females) of 22 tested. The mean age at last review (March 1996) was 31.5 years (range 24 to 36 years). Clinical assessment documented findings of large mouth and jaw with deep set eyes, and microcephaly in nine patients (two having a large head size for height). No patient was hypopigmented; 1/11 patients was fair. Outbursts of laughter occurred in all patients but infrequently in 7/11 (64%) and a constant happy demeanour was present in 5/11 (46%). All had epilepsy, with improvement in 5/11 (46%), no change in 4 (36%), and deterioration in 2 (18%). The EEG was abnormal in 10/10 patients. Ocular abnormalities were reported in 3/8 patients (37.5%) and 4/11 (36%) had developed kyphosis. Two had never walked. All nine who walked were ataxic with an awkward, clumsy, heavy, and/or lilting gait. No patient had a single word of speech but one patient could use sign language for two needs (food and drink). Our data support the concept that AS resulting from deletion is a severe neurological syndrome in adulthood. The diagnosis in adults may not be straightforward as some manifestations change with age. Kyphosis and keratoconus are two problems of older patients.

Abnormalities, Multiple↗