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Biomedical subjects

G M Anderson

Publications and source records attributed to G M Anderson.

At least 55 records · Page 3Linked to original sources
PubMed1998

Fee code creep among general practitioners and family physicians in Ontario: why does the ratio of intermediate to minor assessments keep climbing?

BACKGROUND: "Fee code creep" is the increasing tendency of primary care physicians in Ontario to bill for more intermediate than minor assessments over time. The authors examine the extent and nature of fee code creep and describe physician characteristics associated with the changes. METHODS: A cross-sectional and longitudinal analysis of Ontario Health Insurance Plan billing and physician characteristic data was conducted for fee-for-service general practitioners and family physicians (GP/FPs) in Ontario. The ratio of intermediate to minor assessments (I-M ratio) was determined for the period 1978-79 to 1994-95, and the relation of various physician characteristics to high ratios was tested with bivariate and multivariate analysis. RESULTS: The I-M ratio rose 10-fold, from 0.3 in 1978-79 to 2.9 in 1994-95. Although the I-M ratio was higher for older patients and young children, changes in population age profile over time did not account for any of the increase. The median ratio varied widely among groups of physicians: urban physicians had higher ratios than rural ones (3.9 v. 3.0, p < 0.05), and recent graduates had higher ratios than physicians 60 years of age or older (5.1 v. 2.9, p < 0.05). The I-M ratio was inversely related to number of visits; physicians billing for fewer than 5000 visits had a median ratio of 4.2, whereas those billing for 20,000 visits or more had a median ratio of 1.6. INTERPRETATION: Fee code creep has contributed to expenditure growth in Ontario. This phenomenon was related to both an increase in I-M ratio over time among physicians practising throughout the study period and an influx of new physicians billing at a higher ratio. Creep was not the result of aging of the population.

Adult↗
PubMed1998

Free-standing health care facilities: financial arrangements, quality assurance and a pilot study.

Free-standing health care facilities now deliver many diagnostic and therapeutic services formerly provided only in hospitals. The financial arrangements available to these facilities differ according to whether the services are uninsured or insured. For an uninsured service, such as cosmetic surgery, the patient pays a fee directly to the service provider. For an insured service, such as cataract surgery, the provincial government uses tax revenues to fund the facility by paying it a facility fee and remunerates the physician who provided the service with a professional fee. No comprehensive, proactive quality assurance efforts have been implemented for either these facilities or the clinical practice provided within them. A pilot study involving therapeutic facilities in Ontario has suggested that a large-scale quality improvement effort could be undertaken in these facilities and rigorously evaluated.

Ambulatory Care Facilities↗
PubMed1998

Trends in hospital use for mechanical neck and back problems in Ontario and the United States: discretionary care in different health care systems.

OBJECTIVE: To describe and compare trends in hospital admission rates for mechanical neck and back problems between 1982 and 1992 in Ontario and the United States. DESIGN: A descriptive analysis of hospital admissions, with data for Ontario extracted from the Canadian Institute for Health Information database and data for the US extracted from the National Hospital Discharge Survey. SETTING: All acute care hospitals in Ontario and a probability sample of acute care hospitals in the US. PATIENTS: Adults aged 20 years or more who were admitted to an acute care hospital for mechanical neck or back problems in 1982, 1987 or 1992. Mechanical neck and back problems were defined using an algorithm developed by the study team. OUTCOME MEASURE: Hospital admission rate per 100,000 adults. RESULTS: Between 1982 and 1992 the hospital admission rate for medically treated cases decreased by 52% in Ontario and by 75% in the US. Over the same period the admission rate for surgically treated cases increased by 14% and by 35% respectively. By 1992 the admission rate for medically treated cases in the US was 23% higher than that in Ontario, whereas the rate for surgically treated cases was 164% higher. CONCLUSIONS: The hospital-based medical or surgical treatment of mechanical neck and back problems provides an example of discretionary care. The higher admission rates for surgery in the US may reflect a larger supply of surgical specialists and imaging units. Further work is needed to confirm these findings for other types of discretionary care and to compare the appropriateness of care and clinical outcomes for discretionary care in these 2 jurisdictions.

Adult↗
PubMed1998

Dopamine beta-hydroxylase: two polymorphisms in linkage disequilibrium at the structural gene DBH associate with biochemical phenotypic variation.

Levels of the enzyme dopamine beta-hydroxylase (DbetaH) in the plasma and cerebrospinal fluid (CSF) are closely related biochemical phenotypes. Both are under strong genetic control. Linkage and association studies suggest the structural gene encoding DbetaH (locus name, DBH) is a major locus influencing plasma activity of DbetaH. This study examined relationships of DBH genotype determined at two polymorphic sites (a previously described GT repeat, referred to as the DBH STR and a single-base substitution at the 3' end of DBH exon 2, named DBH*444 g/a), to CSF levels of DbetaH protein in European-American schizophrenic patients, and to plasma DbetaH activity in European-American patients with mood or anxiety disorders. We also investigated linkage disequilibrium (LD) between the polymorphisms in the pooled samples from those European-American subjects (n=104). Alleles of DBH*444 g/a were associated with differences in mean values of CSF DbetaH levels. Alleles at both polymorphisms were associated with plasma DbetaH activity. Significant LD was observed between respective alleles with similar apparent influence on biochemical phenotype. Thus, allele A3 of the DBH STR was in positive LD with DBH*444a, and both alleles were associated with lower plasma DbetaH activity. DBH STR allele A4 was in positive LD with DBH*444 g, and both alleles were associated with higher plasma DbetaH activity. The results confirm that DBH is a major quantitative trait locus for plasma DbetaH activity, and provide the first direct evidence that DBH also influences CSF DbetaH levels. Both polymorphisms examined in this study appear to be in LD with one or more functional polymorphisms that mediate the influence of allelic variation at DBH on DbetaH biochemical phenotypic variation

Anxiety Disorders↗
PubMed1998

Celestial marriage and earthly rents: interests and the prohibition of polygamy.

Just prior to the Civil War, the US government set out on a relentless campaign to eliminate polygamy within the Mormon Church. This paper offers evidence that the political restrictions on the practice of polygamy were the result of rent seeking by potential beneficiaries of such laws (the Edmonds Act of 1882). Polygamy created benefits for women, but reduced the welfare of most men, in a time period when only adult males had the franchise.

Americas↗
PubMed1998

Tryptophan depletion during continuous CSF sampling in healthy human subjects.

The tryptophan (TRP) depletion paradigm has been employed to investigate mood and behavioral effects of acutely lowering plasma TRP, and presumably brain serotonin (5-hydroxytryptamine [5-HT]) levels through administration of a special diet and/or amino acid drink. Our goal was to test the assumption that a corresponding fall in central levels of TRP and 5-HT (measured by its major metabolite, 5-hydroxyindoleacetic acid [5-HIAA]) occurs during the standard execution of this method in healthy adult subjects. Three males and two females completed the protocol, which included a one-day low-TRP diet and a TRP-free amino acid drink. Lumbar puncture was performed, with placement of an indwelling catheter connected to a peristaltic pump and fraction collector. Cerebrospinal fluid (CSF) was sampled continuously for a 13.5-hour period (before, during, and after the drink), with fractions removed every 15 minutes. Plasma samples were simultaneously obtained. CSF TRP levels and plasma TRP levels were highly correlated, falling a mean of 92% and 85% from baseline, respectively. CSF nadirs were reached several hours after plasma nadirs. CSF 5-HIAA decreased modestly (24% to 40%, mean 31% change from baseline), with lowest concentrations observed 8-12 hours after the amino acid drink. These data suggest that TRP depletion results in substantial declines in central 5-HT turnover.

Adult↗
PubMed1998

Pulsatile luteinizing hormone secretion in the ovariectomized, thyroidectomized red deer hind following treatment with dopaminergic and opioidergic agonists and antagonists.

Two experiments were conducted to determine whether dopaminergic or opioidergic pathways are modulated by thyroid gland secretions for seasonal suppression of LH secretion in red deer hinds. Ovariectomized (n = 5) or ovariectomized and thyroidectomized (n = 4) hinds, treated with estradiol implants, received the dopamine agonist bromocriptine or the antagonist sulpiride during pulse bleeds in July (breeding season) and October (nonbreeding season). Comparison of July and October mean plasma LH concentration (3.5 +/- 1.3, 0.7 +/- 0.1 ng/ml, respectively), pulse frequency (1.9 +/- 0.4, 0.7 +/- 0.2 pulses/4 h), and pulse amplitude (1.3 +/- 0.5, 0.7 +/- 0. 02 ng/ml) showed lower (p < 0.05) levels in October, and these levels were not significantly affected by thyroidectomy or drug treatment. In the absence of estradiol implants, the hinds received bromocriptine or morphine during the breeding season (July) and their antagonists, sulpiride or naloxone, respectively, in the nonbreeding season (November). In euthyroid hinds there was a seasonal decrease (p < 0.05) in mean plasma LH concentration, pulse frequency, and pulse amplitude, which did not occur in thyroidectomized hinds. There were no effects of drug treatment on LH concentration except for a small increase following sulpiride in November. Plasma prolactin concentration was significantly increased by antagonists and decreased by agonists on most occasions. We conclude that in red deer hinds, seasonal regulation of LH secretion does not involve dopamine or endogenous opioids and the thyroid gland is required specifically for LH suppression in the absence of estradiol.

Analgesics, Opioid↗
PubMed1998

Effects of diagnosis, race, and puberty on platelet serotonin levels in autism and mental retardation.

OBJECTIVE: To reevaluate platelet serotonin (5-HT) levels in autism, measuring and controlling for effects of race and puberty. The specificity of hyperserotonemia for autism versus cognitive impairment is also assessed. METHOD: Platelet 5-HT levels were measured in 77 individuals, aged 2 through 37 years, with autistic disorder; 65 normal controls; and 22 mentally retarded or otherwise cognitively impaired (MR/CI) prepubertal children. Effects of diagnosis, race, and pubertal status were evaluated by analysis of variance in separate pre- and postpubertal groups. 5-HT levels were expressed as ng/mL blood and ng/microL platelet volume. RESULTS: Among prepubertal children, significant effects of diagnosis (ng/mL; F2,109 = 5.9, p = .004) and race (F2,109 = 14.7, p < .0005) were found. Autistic youngsters had significantly higher 5-HT concentrations than controls, although the elevation (25%) was less than typically reported; MR/CI children had levels very similar to those of controls. White children had significantly lower 5-HT levels than black or Latino youngsters, regardless of diagnosis. Diagnosis and race effects were nonsignificant in the postpubertal group. Postpubertal subjects had lower 5-HT concentrations than prepubertal subjects (ng/mL; F1,114 = 28.5, p < .0005). CONCLUSIONS: The data underscore the importance of matching for race and pubertal status in neuropsychiatric research and suggest that the prevalence of hyperserotonemia in autistic individuals may have been overestimated because of a failure to control for both variables. Hyperserotonemia was not found in MR/CI youngsters without autistic features.

Adolescent↗
PubMed1998

A double-blind, placebo-controlled, crossover trial of an antiandrogen in the treatment of Tourette's syndrome.

The objective of this study was to document the effects of androgen receptor blockade on tic and obsessive-compulsive symptoms in Tourette's syndrome (TS) patients. Thirteen adult TS subjects, 10 men and 3 women, completed 3 weeks of each phase of a double-blind, placebo-controlled, crossover trial of flutamide, a selective androgen receptor antagonist. Symptom severity ratings and hormone levels were obtained at each of the trial's six clinic visits. Flutamide was well-tolerated and produced a significant reduction in motor but not phonic tic symptom severity. It modestly improved symptoms of obsessive-compulsive disorder in the men who had this disorder. Changes in hormone levels during flutamide administration provided evidence for the existence of physiologic mechanisms that compensate for the blocking of the androgen receptor. The therapeutic effects of flutamide are modest in magnitude and they seem to be short-lived, possibly because of physiologic compensation for androgen receptor blockade. Given the potentially serious side effects of flutamide, the use of this agent in the treatment of tics should be reserved for patients who have relatively debilitating symptoms. The therapeutic and endocrine findings may have implications for understanding the sex differences in TS prevalence and the sex-specific variability in the phenotypic expression of the putative TS vulnerability genes.

Adult↗
PubMed1998

Effects of thyroidectomy and thyroxine replacement on seasonal reproduction in the red deer hind.

Two experiments were conducted to test whether thyroid hormones are required for the cessation of the breeding season in female red deer. In Expt 1, 16 mature hinds were allocated early in the breeding season (May) to the following groups: thyroidectomized (THX), thyroidectomized and treated with subcutaneous thyroxine implants which increased plasma tri-iodothyronine to physiological concentrations (THX + T4), or euthyroid controls. Plasma progesterone concentrations consistent with oestrous cyclicity were evident in all hinds during the breeding season (May-September) but after 23 September plasma progesterone concentrations became generally low (< 2.0 nmol l-1) in control and THX + T4 hinds. In contrast, thyroidectomized hinds not receiving thyroxine continued to exhibit circulating progesterone comparable with breeding season concentrations until the end of the experiment (late December). Nine hinds were ovariectomized or ovariectomized and thyroidectomized in May and treated with subcutaneous oestradiol-impregnated capsules, which were removed for periods of about 1 months during August, November and January, to test whether thyroid hormones are involved in the seasonal decline of LH secretion (Expt 2). In the presence of oestradiol, basal LH concentrations and episodic LH secretion were low during the non-breeding season (September-March) (P < 0.05). During this season, basal and GnRH-induced LH concentrations and LH pulse frequency remained similar for both groups except in the absence of oestradiol, when basal LH (3.1 +/- 0.8 versus 1.3 +/- 0.5 ng ml-1, P < 0.05 and GnRH-induced LH (25.9 +/- 3.6 versus 4.7 +/- 0.4 ng ml-1, P < 0.001) concentrations were higher in thyroidectomized hinds than in euthyroid hinds, respectively. Twenty-five hinds were ovariectomized and thyroidectomized during the breeding season and treated with subcutaneous thyroxine implants at different times to identify when thyroid hormones are required to be present to suppress LH concentrations during the non-breeding season in the absence of oestradiol. Thyroxine treatment at the beginning of or during the non-breeding season was effective in suppressing plasma LH concentration, but this action of thyroid hormones did not occur during the breeding season. These results indicate that, in red deer hinds thyroxine is required for termination of the breeding season and that thyroid gland secretions specifically block steroid-independent inhibition of reproductive activity during the non-breeding season. This inhibitory mechanism requires thyroid hormones to be present only from around the time of the end of the breeding season for their normal expression, and they remain responsive to thyroid hormones after this period.

Animals↗
PubMed1998

Hospitalizations for back and neck problems: a comparison between the Province of Ontario and Washington State.

OBJECTIVE: To examine back and neck hospitalizations in the Province of Ontario and Washington State. Because of their different organization and financing, there has been considerable interest in comparing healthcare systems in Canada and the United States. Features of healthcare systems might be expected to result in greater variations in care for elective than urgent conditions. DATA SOURCE: Automated hospital discharge databases. STUDY DESIGN: Previously developed algorithms were used to identify surgical and nonsurgical hospitalizations for back and neck problems in the administrative databases. We compared overall rates of hospitalization and lengths of hospital stay in Ontario and Washington as well as small area variations within the province and state. PRINCIPAL FINDINGS: Surgical back and neck hospitalizations were three times as common in Washington, but medical hospitalizations were twice as common in Ontario. Provincial lengths of stay were longer for both surgical and nonsurgical hospitalizations. Admission rates varied substantially and significantly among small areas in both Washington and Ontario. Variations in hospital length of stay were greater in Ontario, particularly for nonsurgical back and neck hospitalizations. CONCLUSION: The two jurisdictions had very different patterns of hospital utilization for one of the most common health problems seen by physicians. Our results suggest that the global controls on hospital budgets and access to technology in Ontario were associated with lower rates of surgery, higher rates of hospital-based medical care, and longer lengths of stay. They also indicate that the utilization review process in Washington was associated with lower small area variation rates for medical back care.

Adult↗
PubMed1997

Carbonyl histochemistry in rat reperfusion nerve injury.

Free radical mediated, site-specific lipid and protein oxidation has been implicated in the pathophysiology of an ischaemic/reperfusion injury. The aim of the present study was to determine whether carbonyl formation could be detected histochemically in reperfused rat sciatic nerves. We also examined the effects of preischaemic alpha-tocopherol supplementation on carbonyl formation in reperfused nerves. Seven hours of near-complete ischaemia was induced in rat right hindlimb by occlusion of major arteries using microvascular clips. Histochemical detection of carbonyl compounds, applying naphthoic acid hydrazide (NAH) and Fast Blue B (FBB), was undertaken at thigh, knee and calf levels of sciatic, tibial and peroneal nerves. NAH-FBB reactivity was confined to vessels in reperfused nerves. Positively stained epi-, peri- and endoneurial vessels were invariably observed after 2 h of reperfusion at all levels examined. After 24 and 48 h and 7 days of reperfusion, NAH-FBB-positive vessels were more frequently found at knee and calf levels than at the thigh level. Following preischaemic alpha-tocopherol supplementation, no vessels were stained positively with NAH-FBB, except for some epineurial vessels at knee and calf levels after 2 h of reperfusion. Morphometry in endoneurial vessels at the knee level revealed that endothelial cell area in alpha-tocopherol-treated reperfused nerves was significantly less when compared with those in reperfused nerves without alpha-tocopherol. In conclusion, we have demonstrated histochemical evidence of carbonyl formation in vessels, but not with nerve fibres, in ischaemic/reperfused rat sciatic nerves. These abnormalities were prevented with preischaemic supplementation of alpha-tocopherol.

Animals↗
PubMed1997

Epithelial antibiotic induced in states of disease.

Epithelial defensins provide an active defense against the external microbial environment. We investigated the distribution and expression of this class of antimicrobial peptides in normal cattle and in animals in varying states of disease. beta-defensin mRNA was found to be widely expressed in numerous exposed epithelia but was found at higher levels in tissues that are constantly exposed to and colonized by microorganisms. We observed induction in ileal mucosa during chronic infection with Mycobacterium paratuberculosis and in bronchial epithelium after acute infection with Pasteurella haemolytica. It has been proposed that expression of antimicrobial peptides is an integral component of the inflammatory response. The results reported here support this hypothesis and suggest that epithelial defensins provide a rapidly mobilized local defense against infectious organisms.

Animals↗
PubMed1997

Neonatal ACTH administration elicits long-term changes in forebrain monoamine innervation. Subsequent disruptions in hypothalamic-pituitary-adrenal and gonadal function.

The findings from this study demonstrated that the manipulation of the HPA system resulting from ACTH administration during neonatal development produces long-term, differential effects, not only on adrenocortical activity, but also on the activity and integrity of the forebrain monoamine systems. Increased concentrations of the monoamines within the forebrain regions studied at days 7 and 15, suggest a hastened maturation of these neural systems in animals neonatally treated with ACTH. The observed neurochemical alterations in these animals at one year are suggestive of an accelerated aging in the monoamine systems. A further consequence of these disturbances during development is an altered functioning of the HPG axis, as demonstrated by a delayed onset of puberty as previously reported, as well as significantly decreased proestrus plasma estradiol. Although deficits in sexual behavior also existed, it seems probable that these behavioral changes are a manifestation of altered neural systems regulating the ability to cope with a novel stimulus or situation, rather than a disruption of the "feminization" of the brain during sexual differentiation. This is in contrast to the male rat which exhibits permanent deficits in male typical sexual behavior following developmental ACTH treatment. The clinical relevance of these findings may be extensive. Perinatal exposure to events or agents that markedly increase ACTH and the corticosteroids may cause significant immediate and long-term changes in central monoamine functioning. These changes may constitute some of the most deleterious effects of stress exposure in infants and children. The alterations may be especially devastating in individuals with predispositions to stress-sensitive disorders such as anxiety, depression, and Tourette's syndrome. Finally, the use of ACTH in the treatment of infantile spasms may need to be reassessed in light of the possible long-term effects of ACTH on central monoamine functioning.

Adrenocorticotropic Hormone↗
PubMed1997

Human beta-defensin-1 is a salt-sensitive antibiotic in lung that is inactivated in cystic fibrosis.

A human bronchial xenograft model was used to characterize the molecular basis for the previously described defect in bacterial killing that is present in the cystic fibrosis (CF) lung. Airway surface fluid from CF grafts contained abnormally high NaCl and failed to kill bacteria, defects that were corrected with adenoviral vectors. A full-length clone for the only known human beta-defensin (i.e., hBD-1) was isolated. This gene is expressed throughout the respiratory epithelia of non-CF and CF lungs, and its protein product shows salt-dependent antimicrobial activity to P. aeruginosa. Antisense oligonucleotides to hBD-1 ablated the antimicrobial activity in airway surface fluid from non-CF grafts. These data suggest that hBD-1 plays an important role in innate immunity that is compromised in CF by its salt-dependent inactivation.

Amino Acid Sequence↗