Search PubMed⌕ Search

Biomedical subjects

A F Smith

Publications and source records attributed to A F Smith.

At least 37 records · Page 2Linked to original sources
PubMed2001

Retinal capillary hemangioma: a comparison of sporadic cases and cases associated with von Hippel-Lindau disease.

OBJECTIVE: To report observations regarding the onset of tumors in patients with retinal capillary hemangiomas (RCH) and comparing sporadic cases with those associated with von Hippel-Lindau (VHL) disease. DESIGN: Retrospective consecutive case series. PARTICIPANTS: Sixty-eight patients with RCH managed at a tertiary referral center. MAIN OUTCOME MEASURES: The data were analyzed for age at diagnosis of RCH, two-hit mutation model, onset of new tumors, and random (Poisson) distribution. RESULTS: Among 68 patients, we identified 174 RCHs in 86 eyes. Thirty-one patients had VHL disease, and 37 patients were sporadic. The median age at diagnosis in cases with VHL disease was 17.6 years (range, 2.8-46.7 years), and in those without VHL disease it was 36.1 years (range, 7.0-74 years). The age distribution of RCH followed a two-hit mutation model. In eyes with VHL disease, the total number of RCH were distributed randomly as calculated by the Poisson distribution (mean number of tumors = 4). Overall onset of 33 new tumors was documented in 11 eyes (13%) over a median interval of 16 months (range, 3-235 months). All new tumors developed before the age of 47 years. The retinal location of new tumors was similar to the previous tumors with most new tumors located in the superotemporal quadrant (42%) and in the midperipheral retina (58%). Of the 50 patients initially manifesting solitary RCH, only 4 had new tumors develop over a median follow-up duration of 6.4 years (range, 0-33 years). All four cases had VHL disease. CONCLUSIONS: The median age at diagnosis of RCH in patients with VHL disease was almost 18 years less than those without VHL disease. The age distribution of RCH followed the two-hit mutation model. In VHL disease, the number of RCH is determined randomly. Most of the new RCH develop by the age of 47 years. In the absence of VHL disease, it is unlikely for patients with solitary RCH to develop new tumors.

Adolescent↗
PubMed2001

A utility analysis correlation with visual acuity: methodologies and vision in the better and poorer eyes.

OBJECTIVE: To ascertain the correlation between visual acuity levels and ophthalmic utility values obtained using time tradeoff and standard gamble utility analysis methodologies. METHODS: Three hundred twenty-five consecutive patients with visual loss to 20/40 or less in at least one eye with predominantly vitreoretinal pathology were evaluated in a cross-sectional fashion using a standardized testing methodology to obtain ophthalmic time tradeoff and standard gamble utility values. Spearman correlation coefficients were employed to correlate the utility values with visual acuity in better seeing and poorer seeing eyes. RESULTS: The Spearman correlation coefficient for time tradeoff utility values and vision in the better seeing eye was 0.455 (p < 0.001), while that for time tradeoff utility values and visual acuity in the poorer seeing eye was 0.268 (p < 0.001). The coefficient for standard gamble utility values and the better seeing eye was 0.371 (p < 0.001), while that for standard gamble utility values and vision in the poorer seeing eye was 0.250 (p < 0.001). CONCLUSIONS: There is a greater correlation between ophthalmic utility values and vision in the better seeing eye, as versus vision in the poorer seeing eye. Time tradeoff ophthalmic utility values demonstrate a greater correlation with vision in the better seeing eye than do standard gamble utility values.

Aged↗
PubMed2001

How shared are age-related influences on cognitive and noncognitive variables?

Several theories have suggested that age-related declines in cognitive processing are due to a pervasive unitary mechanism, such as a decline in processing speed. Structural equation model tests have shown some support for such common factor explanations. These results, however, may not be as conclusive as previously claimed. A further analysis of 4 cross-sectional data sets described in Salthouse, Hambrick, and McGuthry (1998) and Salthouse and Czaja (2000) found that although the best fitting model included a common factor in 3 of the data sets, additional direct age paths were significant, indicating the presence of specific age effects. For the remaining data set, a factor-specific model fit at least as well as the best fitting common factor model. Three simulated data sets with known structure were then tested with a sequence of structural equation models. Common factor models could not always be falsified--even when they were false. In contrast, factor-specific models were more easily falsified when the true model included a unitary common factor. These results suggest that it is premature to conclude that all age-related cognitive declines are due to a single mechanism. Common factor models may be particularly difficult to falsify with current analytic procedures.

Adolescent↗
PubMed2001

Relative efficacy of a brief motivational intervention for college student drinkers.

The authors evaluated the efficacy of Brief Alcohol Screening and Intervention for College Students (BASICS - L. A. Dimeff, J. S. Baer, D. R. Kivlahan, & G. A. Marlatt, 1999), a single session of drinking-related feedback intended to reduce heavy drinking and related harm. College student drinkers (N = 99) were assigned to BASICS, an educational intervention, or an assessment-only control group. At 3 months postintervention. there were no overall significant group differences, but heavier drinking BASICS participants showed greater reductions in weekly alcohol consumption and binge drinking than did heavier drinking control and education participants. At 9 months, heavier drinking BASICS participants again showed the largest effect sizes. BASICS participants evaluated the intervention more favorably than did education participants. This study suggests that BASICS may be more efficacious than educational interventions for heavier drinking college students.

Adult↗
PubMed2001

Risk perception and communication: recent developments and implications for anaesthesia.

This review begins by outlining the history of probability theory, exposing cultural differences between scientists and lay people in the way risks are viewed. The basic principles of the science of risk perception are described, and the various methods of communicating risk in health care, both verbal and numerical, are then discussed critically. These concepts are then applied to the practice of anaesthesia. Risk perception may affect anaesthetists' choice of career and may be involved in the genesis and evolution of critical incidents; we also discuss possibilities for training in risk perception issues. The place of risk communication in informed consent and its ethical implications are discussed.

Anesthesia↗
PubMed2001

The economic impact of ophthalmic services for persons with diabetes in the Canadian Province of Nova Scotia: 1993-1996.

PURPOSE: If undetected and untreated, diabetic retinopathy can lead to severe vision loss and irreversible blindness, imposing both clinical and economic costs to patients and society. The purpose of this study, therefore, was to determine both the direct and indirect costs of providing ophthalmic, social and rehabilitative services for persons with diabetic eye disease. METHODS: Persons with diabetes and seen by ophthalmologists in the Canadian Province of Nova Scotia were ascertained from provincial health records for the years 1993-1996, inclusive. In addition, utilization data from community and blindness rehabilitation agencies located throughout the Province of Nova Scotia for the same time period were also obtained and analyzed. A cost-of-illness analysis of ophthalmic and additional services for persons with diabetes was then performed using the available data sources. RESULTS: The total cost of direct and indirect ophthalmic, disability and rehabilitative care for persons with diabetes mellitus in Nova Scotia over the study period, 1993-1996, was estimated to be CDN $10,521,816.58. Direct costs amounted to CDN $1,416,355.05 (13.46%), indirect costs due to lost productivity reached CDN $5,072,831.85 (48.22%), rehabilitation services cost CDN $251,204.08 (2.38%), disability payments amounted to CDN $979,992.00 (9.32%), while lost wages due to disability payments measured a further CDN $2,801,433.60 (26.62% of total costs). CONCLUSIONS: Over the period reviewed, ophthalmic costs rose by a factor 3.2 greater than that observed for goods and services captured by the Canadian Consumer Price Index. Further analyses over a longer follow-up period are required to definitively establish whether or not there is a long-term upward trend in ophthalmic costs.

Adolescent↗
PubMed2001

Penetrating keratoplasty in iridocorneal endothelial syndrome.

PURPOSE: To evaluate the clinical outcome of penetrating keratoplasty (PK) in iridocorneal endothelial (ICE) syndrome. METHODS: Clinical charts of patients who underwent penetrating keratoplasty for ICE syndrome between 1985 and 1999 were reviewed retrospectively. Glaucoma control, best corrected visual acuity pre- and post-PK, graft clarity, graft rejection episodes, improvement in pain, and additional procedures were analyzed. RESULTS: Fourteen cases were reviewed with an average follow-up of 58 months after PK. Initial grafts failed in seven patients (50%), in six cases because of rejection, and one owing to endothelial failure without signs of rejection. Repeat PKs were performed in six patients. At final follow-up, 12 grafts were clear. Glaucoma was controlled pre- and post-PK (average intraocular pressure, 16 mmHg for both eyes). Pre-PK, eight patients were using glaucoma medicines and nine had had glaucoma surgery. At the end of the follow-up, seven patients were using glaucoma medicines; six patients required glaucoma surgery after their initial PK. At the final follow-up visit, visual acuity in three patients (21%) was 20/40 or better, it ranged from 20/50 to 20/100 in four patients (29%) and 20/200 to 20/400 in five patients (36%), and in two patients with failed grafts (14%) it was counting fingers or worse. CONCLUSION: Clear grafts were achieved in 12 cases, although six patients (43%) underwent repeat PKs. All patients had glaucoma, which was controlled before and after PK by medical treatment and surgical procedures. Favorable outcomes can be achieved in patients with ICE syndrome but may require multiple corneal and glaucoma procedures.

Adult↗
PubMed2001

Binocular vision recovery in bilateral keratoplasty.

PURPOSE: To determine the benefit of bilateral penetrating keratoplasty with regard to binocular vision. METHODS: We compared patients who underwent corneal transplantation bilaterally with patients who had successful corneal transplantation in one eye and corneal disease in the other eye. Specifically, changes in fusion, stereopsis, and binocular vision function were analyzed. A questionnaire regarding performance of daily tasks was given. RESULTS: Patients with bilateral keratoplasty performed better in all the analyzed functions. Fusion was achieved by 81.25% in the unilateral group versus 100% in the bilateral group (p = 0.15). Stereopsis was present more in the bilateral group (100% vs. 62.5%, p = 0.008) and the quantity of stereopsis was significantly better in the bilateral group (121 seconds of arc vs. 1,284 seconds of arc, p = 0.014). 88.8% of the patients subjectively improved in daily activities after second eye surgery. CONCLUSION: There are objective and subjective improvements after bilateral penetrating keratoplasty.

Activities of Daily Living↗
PubMed2001

The effect of state legislation on eye donation.

PURPOSE: Pennsylvania Act 102 implemented in March 1995 required all acute care hospitals in Pennsylvania to routinely refer all deaths to the Organ Procurement Organization for determination of suitability for organ/tissue donation. This study analyzed the effect of the law on eye donation. METHODS: Retrospective analysis of the total number of referrals and the actual number of eye donations from 62 hospitals in Pennsylvania to the Lions Eye Bank of Delaware Valley was performed for the years 1993 to 1998. Information gathered included donor's age, gender, race, cause of death, referring institution, and result of referral. RESULTS: From 1993 to 1998, the total numbers of referrals were 988, 1,647, 8,101, 21,123, 21,783, and 22,987, and the numbers of donors were 570, 574, 660, 644, 594, and 568, respectively. The increase in the number of donors after implementation of the law was not commensurate with the number of referrals. This was caused by a disproportionate increase in the number of referrals older than 70 years of age (from a mean of 33% to 52%), which exceeded the donor age limit of 69 years, and also to a lower family consent rate (from a mean of 48% to 24%). CONCLUSIONS: Well-designed state legislation with proper implementation greatly increased hospital referrals for eye donation. However, there was only a small increase in the number of eye donors because many of the referrals were beyond the acceptable upper age limit for eye donation. A small increase in the donor age limit would increase the number of eye donations without having to expand the potential donor pool. Education of the public may help to improve the family consent rate.

Adolescent↗
PubMed2001

Patient-initiated second medical opinions: their necessity and economic cost.

PURPOSE: To assess the value of patient-initiated second medical opinions (SMO). METHODS: The authors prospectively collected demographic data from 100 consecutive patients. The authors recorded major changes in the patients' care, such as inappropriate surgery recommended, inadequate treatment performed, and appropriate treatment not recommended. The authors also recorded costs incurred or saved by the patients and the third-party payers. RESULTS: In nearly 15 of the cases, the authors had major disagreements with the initial diagnosis or management. Surgery had been recommended in 28 cases. They advised against it in nine. In 72 cases, no surgery had been recommended. They advised and performed it in five. The management of five other patients was not in accordance with that recommended by large clinical trials or was inadequately done. Including the consultation fees, surgery performed or advised against, retinal angiography, and ultrasonography, the 100 SMO cost third-party payers $12,426. If the authors subtract the cost of noncontroversial surgery they recommended and if the patients had paid the consultation fee and had brought along their fluorescein angiograms, third-party payers would have saved $4,079. CONCLUSION: The savings SMO generated by eliminating unnecessary surgery resulted in improved patient care at minimal cost to third-party payers.

Adolescent↗
PubMed2001

Physician manpower and health care expenditures in the United States: a thirty-year perspective.

Data gathered on the number of physicians and health care costs in the United States over a 30-year period from 1970 through 1999 were correlated and analyzed using bivariate linear regression. The rise in the number of practicing physicians theoretically predicts 96 percent of the variability in rise of total U.S. health expenditures, 96 percent of the variability in rise of physician service expenditures, 98 percent of the variability in rise of hospital service expenditures, and 86 percent of the variability in rise of prescription pharmaceutical expenditures. If the rate of growth in the number of physicians continues unchanged in the current fee-for-service climate, the model herein predicts that the growth in health care costs will likely continue to rise substantially faster than the rate of growth of the U.S. population and the rate of inflation. The addition of nonphysician providers with the same clinical privileges will likely exacerbate the situation of rapidly escalating medical costs. It is also possible that the excess number of physicians and other health care providers with the same clinical privileges as physicians may decrease the overall quality of health care. Reducing the rise in the number of physicians and nonphysician practitioners may help to decrease overall health care expenditures and improve overall quality of health care in the United States.

Allied Health Personnel↗
PubMed2000

Evidence-based medicine as Bayesian decision-making.

We review two recent trends: the emergence of evidence-based medicine and the growing use of Bayesian statistics in medical applications. Evidence-based medicine requires an integrated assessment of the available evidence, and associated uncertainty, but there is also an emphasis on decision-making, for individual patients, or at other points in the health-care system. This demands consideration of the values and costs associated with potential outcomes. We argue that the natural statistical framework for evidence-based medicine is a Bayesian approach to decision-making that incorporates an integrated summary of the available evidence and associated uncertainty with assessment of utilities. We outline a practical agenda for further development.

Bayes Theorem↗
PubMed2000

Hepatocyte nuclear factor-3 homologue 1 (HFH-1) represses transcription of smooth muscle-specific genes.

Results show that smooth muscle-specific promoters represent novel downstream targets of the winged helix factor hepatocyte nuclear factor-3 homologue 1 (HFH-1). HFH-1 strongly represses telokin promoter activity when overexpressed in A10 vascular smooth muscle cells. HFH-1 was also found to repress transcription of several other smooth muscle-specific promoters, including the SM22alpha promoter. HFH-1 inhibits telokin promoter activity, by binding to a forkhead consensus site located within an AT-rich region of the telokin promoter. The DNA-binding domain alone was sufficient to mediate inhibition, suggesting that binding of HFH-1 blocks the binding of other positive-acting factors. HFH-1 does not disrupt serum response factor binding to an adjacent CArG box within the telokin promoter, implying that HFH-1 must compete with other unidentified trans-activators to mediate repression. The localization of HFH-1 mRNA to the epithelial cell layer of mouse bladder and stomach implicates HFH-1 in repressing telokin expression in epithelial cells. This suggests that cell-specific expression of telokin is likely mediated by both positive-acting factors in smooth muscle cells and negative-acting factors in nonmuscle cell types. We propose a model in which the smooth muscle specificity of the telokin promoter is regulated by interactions between positive- and negative-acting members of the hepatocyte nuclear factor-3/forkhead family of transcription factors.

Animals↗
PubMed2000

Premedication for anxiety in adult day surgery.

BACKGROUND: Surgery is increasingly performed on a day-case basis. Many patients are anxious pre-operatively and might benefit from pharmacological anxiolysis. Drugs are sometimes not used, however, for fear of delaying discharge from hospital. OBJECTIVES: To asses the effect of anxiolytic premedication on time to discharge in adult patients undergoing day case surgery under general anaesthesia. SEARCH STRATEGY: Trials were identified by computerised searches of the Cochrane Controlled Trials Register, MEDLINE, EMBASE, by checking the reference lists of trials and review articles, by hand-searching three main anaesthesia journals and by contacting five researchers active in the field and the Product Information departments of the manufacturers of five commonly used premedicants. SELECTION CRITERIA: All randomised controlled trials comparing an anxiolytic drug(s) with placebo before general anaesthesia in adult day case surgical patients. DATA COLLECTION AND ANALYSIS: We collected data on anaesthetic drugs used, results of tests of psychomotor function where these were used to assess residual effect of premedication, and on times from end of anaesthesia to ability to walk unaided or readiness for discharge from hospital. Formal statistical synthesis of individual trials was not performed in view of the variety of drugs studied. MAIN RESULTS: Searching identified twenty-nine reports; fourteen studies, with data from a total of 1263 patients, were considered eligible for analysis. Only two studies specifically addressed the discharge question; both found no delay in premedicated patients. Three other studies used clinical criteria to assess fitness for discharge, though times were not given. Again, there was no difference from placebo. Four studies used both clinical measures and tests of psychomotor function as tests of recovery from anaesthesia. In none of these studies did the premedication appear to delay discharge, although performance on tests of psychomotor function was sometimes still impaired. Of the four studies which used tests of psychomotor function to assess recovery, three showed impaired recovery (after midazolam 7.5mg, midazolam 15mg or diazepam 15mg) which might possibly interfere with discharge from hospital. REVIEWER'S CONCLUSIONS: We have found no evidence of a difference in time to discharge from hospital in patients who received anxiolytic premedication. However, in view of the age and variety of anaesthetic techniques used, inferences for current day-case practice should be made with caution.

Adult↗
PubMed2000

Premedication for anxiety in adult day surgery.

BACKGROUND: Surgery is increasingly performed on a day-case basis. Many patients are anxious pre-operatively and might benefit from pharmacological anxiolysis. Drugs are sometimes not used, however, for fear of delaying discharge from hospital. OBJECTIVES: To asses the effect of anxiolytic premedication on time to discharge in adult patients undergoing day case surgery under general anaesthesia. SEARCH STRATEGY: Trials were identified by computerised searches of the Cochrane Controlled Trials Register, MEDLINE, EMBASE, by checking the reference lists of trials and review articles, by hand-searching three main anaesthesia journals and by contacting five researchers active in the field and the Product Information departments of the manufacturers of five commonly used premedicants. SELECTION CRITERIA: All randomised controlled trials comparing an anxiolytic drug(s) with placebo before general anaesthesia in adult day case surgical patients. DATA COLLECTION AND ANALYSIS: We collected data on anaesthetic drugs used, results of tests of psychomotor function where these were used to assess residual effect of premedication, and on times from end of anaesthesia to ability to walk unaided or readiness for discharge from hospital. Formal statistical synthesis of individual trials was not performed in view of the variety of drugs studied. MAIN RESULTS: Searching identified twenty-nine reports; fourteen studies, with data from a total of 1263 patients, were considered eligible for analysis. Only two studies specifically addressed the discharge question; both found no delay in premedicated patients. Three other studies used clinical criteria to assess fitness for discharge, though times were not given. Again, there was no difference from placebo. Four studies used both clinical measures and tests of psychomotor function as tests of recovery from anaesthesia. In none of these studies did the premedication appear to delay discharge, although performance on tests of psychomotor function was sometimes still impaired. Of the four studies which used tests of psychomotor function to assess recovery, three showed impaired recovery (after midazolam 7.5mg, midazolam 15mg or diazepam 15mg) which might possibly interfere with discharge from hospital. REVIEWER'S CONCLUSIONS: We have found no evidence of a difference in time to discharge from hospital in patients who received anxiolytic premedication. However, in view of the age and variety of anaesthetic techniques used, inferences for current day-case practice should be made with caution.

Adult↗
PubMed2000

Concurrent choroidal melanoma in son and father.

PURPOSE: To report the concurrent occurrence of choroidal melanoma in a son and father. METHODS: Case reports. The likelihood of familial occurrence of uveal melanoma in which father and son are affected was estimated using the principles of probability. RESULTS: Unilateral choroidal melanoma was diagnosed in a 41-year-old man. Three months later, his 68-year-old father presented with a pigmented choroidal mass that greatly increased in size during the next 6 months and was diagnosed a choroidal melanoma. No personal or family history of atypical moles, cutaneous melanoma, or other malignancy existed. The likelihood of familial occurrence of uveal melanoma using principles of probability was estimated to be 1 in 10 million. CONCLUSION: Considering the low prevalence of uveal melanoma in the general population, the likelihood of uveal melanoma occurring in a family setting is remote.

Adult↗