Showing papers by "Sunnybrook Health Sciences Centre published in 1991"

Fear of falling and postural performance in the elderly

Abstract: A cross-sectional study was performed to investigate the association between fear of falling and postural performance in the elderly. One hundred ambulatory and independent volunteers (aged 62-96) were subjected to five types of balance tests: (a) spontaneous postural sway, (b) induced anterior-posterior sway, (c) induced medial-lateral sway, (d) one-leg stance, and (e) a clinical balance assessment scale. Pseudorandom platform motions were used in the induced-sway tests. The subjects were classified into both "faller"/"nonfaller" and "fear"/"no-fear" categories, to allow the influence of fear of falling and falling history to be separated in the analyses. Subjects who expressed a fear of falling were found to exhibit significantly poorer performance in blindfolded spontaneous-sway tests and in eyes-open, one-leg stance tests. The clinical scale was the only balance measure that showed a significant association with retrospective, self-reported falling history. We could not ascertain whether the fear of falling affected balance-test performance in an artifactual manner, or whether the fear and poorer performance were related to a true deterioration in postural control. Until this issue can be resolved, balance-test performance should be interpreted with caution when testing apprehensive individuals. Furthermore, studies of postural control and falling should allow for the potentially confounding influence of fear of falling.

Vascular risks of asymptomatic carotid stenosis.

Abstract: We sought to determine the risks of stroke, myocardial ischemia, and vascular death in patients with asymptomatic carotid stenosis.Six hundred ninety-six patients with asymptomatic carotid stenosis referred to the Doppler laboratory were followed prospectively for a mean time of 41 months. These patients were studied both clinically and by carotid Doppler ultrasound, including evaluation of the effect of stroke risk factors.Transient ischemic attacks occurred in 75 patients and stroke in 29, while 132 had ischemic cardiac events. Five patients died from stroke and 59 from cardiac causes. Annual stroke rate was 1.3% in patients with carotid stenosis less than or equal to 75% and 3.3% in those with stenosis greater than 75%. Ipsilateral stroke rate was 2.5% in patients with greater than 75% carotid stenosis. Annual cardiac event rate was 8.3% and death rate 6.5% in patients with severe carotid stenosis.With carotid stenosis less than or equal to 75%, the stroke rate is negligible (1.3% annually) whereas the...

Are history and physical examination a good screening test for sleep apnea

Abstract: ▪ Objective: To determine whether presenting clinical history, pharyngeal examination, and the overall subjective impression of the clinician could serve as a sensitive screening test for sleep apn...

Characterization of lead zirconate titanate ceramics for use in miniature high-frequency (20-80 MHz) transducers

Abstract: The material properties of lead zirconate titanate (PZT) ceramics for operation in the thickness mode at frequencies as high as 80 MHz are reported. Each of the ceramics tested showed a reduction in k/sub t/ with increasing frequency. In a fine-grained PZT, values of k/sub t/ as high as 0.44 were measured at 80 MHz. The effects of grain size were also evident in the measurement of frequency dependent mechanical losses. Experimental and theoretical analysis of a 1 mm*1 mm, 45 MHz PZT transducer verified the validity of the measurements of the properties and demonstrated excellent insertion loss and bandwidth characteristics. The minimum insertion loss of -17.5 dB is in good agreement with theory and is a marked improvement over the performance of polymer devices. Details on the fabrication and testing of high frequency ceramic transducers are described. >

Efficacy of feedback training in long-standing facial nerve paresis.

Abstract: An efficacious treatment has not been available to patients with aberrant regeneration of the facial nerve as a result of Bell's palsy or after acoustic neuroma excision. This prospective controlled trial examines the efficacy of electromyographic feedback versus mirror feedback as treatment strategies for patients suffering from long-standing (18 months minimum) facial nerve paresis. Twenty-five patients were randomly assigned to electromyography with mirror feedback or mirror feedback alone. Seven rural patients who did not undergo treatment served as controls. At 0, 6, and 12 months, facial motor function was objectively quantified by linear measurement of facial movement, visual assessment of voluntary movement, and electrical measurement of facial nerve response to maximal stimulation. Statistically significant improvements were noted in both electromyography and mirror-feedback groups with respect to symmetry of voluntary movement (P less than .03) and linear measurement of facial expression (P less than .01). The positive results of this controlled trial demonstrate that feedback training in combination with a structured home rehabilitation program is a clinically efficacious treatment for patients with facial nerve paresis.

Fractures of the spine in diffuse idiopathic skeletal hyperostosis.

Abstract: Fractures of the spine in diffuse idiopathic skeletal hyperostosis (DISH) have rarely been reported. Only four cases could be found in the world literature. Eight new cases with nine fractures are reported in this study. The critical features are the frequent delays in diagnosis (three of eight patients) and the high rate of immediate and delayed neurologic deficit (seven of eight patients). Two fracture patterns occurred in this group. The first type occurred through the midportion of an ankylosed segment of the spine and involved the vertebral body (five fractures). The second type occurred at the top or bottom of a fused segment (four fractures). The latter were disk disruptions or odontoid fractures. This is a marked difference from spinal fractures in ankylosing spondylitis, in which the majority are transdiskal fractures. The difference can be explained on the basis of the different pathology of these two disease processes. Careful evaluation of patients with DISH who sustain trauma is critical. Treatment of this rare injury should be early stabilization of the spine to avoid complications of nonunion, deformity, neurologic injury, and death.

Cerebrospinal fluid leaks and meningitis in acoustic neuroma surgery.

Abstract: Cerebrospinal fluid leaks and associated meningitis are the most common life-threatening complications of surgery for acoustic neuromas. This retrospective study reviews 319 patients who had surgery for 321 acoustic tumors at the Sunnybrook Health Sciences Center, University of Toronto, from April 1975 to March 1990. Cerebrospinal fluid leaks occurred after 13.4% of primary tumor operations. Surgical repair was required in 6.2% of all patients; 4.4% needed more than one operation. Meningitis occurred in 5.3% of all patients. These complications were more common in larger tumors and after the combined translabyrinthine middle fossa approach. Transnasopharyngeal eustachian tube obliteration was used to stop recurrent cerebrospinal fluid leaks in two patients.

Practical implementation and optimization of one-shot T1 imaging.

Abstract: Longitudinal relaxation times (T1) can be measured rapidly in an imaging context using a "one-shot" method based on the pulse sequence originally proposed by D. C. Look and D. R. Locker (Rev. Sci. Instrum. 41, 250 1970). This sequence is significantly faster than either repeated inversion recovery or repeated saturation recovery methods. The method uses a 180 degrees inversion pulse followed by multiple small-angle alpha pulses that sample the longitudinal magnetization during its recovery. Choices of inversion pulse, tip angle, and time intervals are discussed for optimal clinical use. We can produce 29 images sampling the full T1 recovery curve with a 256 x 256 resolution in about 10 min. From this data, T1 images can be calculated with a precision of 10%.

Caffeine and Cardiac Arrhythmias

Abstract: Purpose To review the evidence supporting the belief that caffeine causes cardiac arrhythmias. Data sources Studies published since 1982 identified through computerized searches of MEDLINE, TOXLINE, and Chemical Abstracts and a review of bibliographies of relevant articles on the subject of caffeine and cardiac arrhythmias. Study selection All clinical studies examining caffeine as a cause of cardiac arrhythmias and a selection of basic science experiments to illustrate caffeine's effects in vitro. Data extraction Study quality was assessed and all available clinical data pertaining to caffeine as a cause of arrhythmias were summarized. Results of data analysis In one electrophysiologic study, caffeine was associated with an increased susceptibility to provoked cardiac arrhythmias. In five placebo-controlled trials, caffeine in doses up to 500 mg daily (equivalent to 5 to 6 cups of coffee) did not increase the frequency or severity of ventricular arrhythmias. One large epidemiologic study reported an increase in the frequency of ventricular extrasystoles in persons consuming 9 or more cups of coffee daily. Conclusion Moderate ingestion of caffeine does not increase the frequency or severity of cardiac arrhythmias in normal persons, patients with ischemic heart disease, or those with pre-existing serious ventricular ectopy.

X-ray imaging using amorphous selenium: a photoinduced discharge readout method for digital mammography.

Abstract: A new digital image readout method for electrostatic charge images on photoconductive plates is described. The method can be used to read out images on selenium plates similar to those used in xeromammography. The readout method, called the air-gap photoinduced discharge method (PID), discharges the latent image pixel by pixel and measures the charge. The PID readout method, like electrometer methods, is linear. However, the PID method permits much better resolution than scanning electrometers while maintaining quantum limited performance at high radiation exposure levels. Thus the air-gap PID method appears to be uniquely superior for high-resolution digital imaging tasks such as mammography.

Radiosurgery with unflattened 6-MV photon beams

Abstract: One of the major drawbacks to doing stereotactic radiosurgery with a linear accelerator is the long time required to deliver the target dose. Single fractions of 25 Gy delivered at the isocenter and at depth in the skull may require beam times in excess of 15 min for a typical linear accelerator with a maximum dose rate of 250 cGy/min in tissue. In an effort to decrease the treatment time for this technique, the flattening filter has been removed from an AECL Therac-6 linear accelerator and the characteristics of the resulting beam have been measured. Flatness is acceptable for the field sizes used with this technique and the dose rate is increased by a factor of 2.75.

Affective Disorders in First-Degree Relatives of Adolescent Onset Bipolars, Unipolars, and Normal Controls

Abstract: Two hundred and fifty-nine first-degree relatives of 23 adolescent bipolars (81 relatives); 26 unipolars (95 relatives); and 24 normal controls (83 relatives) were assessed for the presence of affective disorders, using the family history method. First-degree relatives of bipolar probands were significantly more likely to have a bipolar illness than those of unipolar probands (p = 0.03) and normal controls (p = 0.001). Rates of unipolar depression in first-degree relatives of bipolars and unipolars were not significantly different but differed significantly between bipolars and normals (p = 0.002) and unipolars and normals (p = 0.006). The implications of these findings for clinical work, diagnosis, and research in adolescents with affective disorders are discussed.

Nocturnal Cortisol, Thyroid Stimulating Hormone, and Growth Hormone Secretory Profiles in Depressed Adolescents

Abstract: Twelve depressed adolescents and 12 controls matched for age, sex, Tanner stage, time of menstrual cycle (females), weight, and time of year assessed were studied over 3 nights. Measurements for cortisol, thyroid stimulating hormone, and growth hormone were made on serum collected at 10 P.M., 12 midnight, 1 A.M., 2 A.M., 3 A.M., 4 A.M., and 6 A.M. in eight pairs and every 20 minutes from 8 P.M. to 7 A.M. in four pairs. Cortisol secretion did not significantly differentiate the groups. Thyroid stimulating hormone secretion was significantly elevated in the depressed group at one time point. Growth hormone secretion significantly differentiated the two groups at most time points, and the depressed adolescents significantly hypersecreted growth hormone (area under the curve). Implications for the diagnosis, etiology, and treatment of adolescent depression are discussed.

Diagnostic utility of the Beck Depression Inventory with adolescent psychiatric outpatients and inpatients

Abstract: The utility of the Beck Depression Inventory (BDI) for differentiating adolescents with depressive disorders from adolescents with non affective psychiatric disorders was examined using a sample of 93 psychiatric outpatients and 26 inpatients. The Diagnostic Interview for Children and Adolescents (DICA) was administered to establish the patients' diagnosis. Psychiatric diagnoses were made by experienced clinicians who used all available information on the patient. The BDI scores discriminated between patients with depressive disorders and patients with non affective psychiatric disorders. This differentiation was true for boys and girls, outpatients and inpatients. The classification accuracy of the instrument was 75% at thresholds of 11 and 16 on the scale. The results indicate that the BDI is a useful instrument for screening for depression in adolescents, and can also be used in conjunction with other tests. However, the BDI by itself is inadequate to establish a diagnosis of depression.

Mycoplasma Pneumoniae Infections and Stevens-Johnson Syndrome Report of Eight Cases and Review of the Literature

Abstract: On the basis of a literature review and eight cases of our own, we analyzed 37 cases of Mycoplasma pneumoniae (MP) infection and Stevens-Johnson syndrome (SJS). Our clinical and laboratory findings do not differ from those reported in the literature for MP infection with no exanthem or for SJS of various etiologies. Eighty percent of the children presented with symptoms of upper respiratory tract infection (URTI) (cough, fever, sore throat, malaise, headache), with a mean of 10 days (range 1 to 30) before skin rash broke out. Skin manifestations occurred in 94.2% of the patients after 3 to 21 days (mean 10.3 days) of fever. The exanthem, composed predominantly of maculopapular and vesicular, was distributed chiefly on the trunk and extremities and lasted less than 14 days in 87.8% of the patients. Stomatitis was observed in 91.6% of the patients and conjunctivitis in 50%. No consistent pattern seems to emerge by which one could predict the existence of MP infection causing SJS. The complications of SJS associated with MP seem less frequent (2.7%) and much less severe than in cases where SJS arises from other reported causes. Because coincidence cannot be excluded from the assessments of the degree and rate of improvement for the few patients treated with corticosteroid, from the low frequency of complications, and from the mortality rate of zero in this series of patients, the use of corticosteroids for SJS associated with MP infection is questionable.

Venous thromboembolism after brain tumor surgery: a retrospective review.

Abstract: We retrospectively reviewed the incidence rate of clinical postoperative deep vein thrombosis and/or pulmonary embolism in 1703 patients undergoing initial craniotomy for meningioma, glioma, or cerebral metastasis. The incidence rate of clinical thromboembolic complications was 1.59% for all tumor groups within the first 4 weeks of surgery. Patients undergoing surgery for meningiomas had a statistically significant increased risk of thromboembolism despite fewer overall perioperative risk factors, when compared with the other tumor groups. The tumor-specific incidence rates of deep vein thrombosis and/or pulmonary embolism for meningioma, glioma, and metastasis were 3.09%, 0.97%, and 1.03%, respectively. Whether this difference was a result of increased surgical time or an inherent property of meningiomas could not be ascertained.

In-vitro assessment of a hypersensitivity syndrome associated with sorbinil.

Abstract: Sorbinil is a hydantoin aldose reductase inhibitor that has shown promise as therapy for patients with diabetic complications such as neuropathy and retinopathy. However, as many as 10% of patients receiving sorbinil have had adverse reactions characterized by fever, skin rash, and myalgia. Our previous studies of phenytoin suggested that susceptibility to reactions might result from an inherited detoxification defect. We did the current study to determine if sorbinil is metabolized to reactive intermediates and if cells from patients with a history of a reaction to sorbinil are appropriate for the in-vitro investigation of susceptibility. Microsome-generated metabolites of sorbinil (50 microM) were toxic to normal peripheral blood lymphocytes (7.9% +/- 0.3% dead cells [mean +/- SE]). Toxicity was increased in the presence of an epoxide hydrolase inhibitor (17.5% +/- 0.3% dead cells) and abolished by an inhibitor of cytochrome P-450. In contrast to cells from healthy controls and diabetics who tolerated sorbinil (7.9% +/- 0.7% and 7.8% +/- 0.4% dead cells, respectively), cells from the six patients who had sorbinil reactions showed significantly increased toxicity from metabolites of sorbinil and phenytoin (19.7% +/- 2.3% dead cells, P less than 0.001). Cells from three patients who had reactions to phenytoin were similarly sensitive to sorbinil metabolites (23.4% +/- 0.3% dead cells). We conclude that sorbinil is oxidatively metabolized to a potentially toxic intermediate. Certain patients may be at increased risk for developing hypersensitivity reactions. Development of this important new drug has been hampered by uncommon but potentially severe reactions. An increased understanding of the steps involved in the development of adverse reactions could lead to screening tests or to the development of safer compounds.

Significance of myocardial contusion following blunt chest trauma.

Abstract: A prospective study was undertaken at a regional trauma unit (RTU) to determine the significance of cardiac complications in patients with blunt chest trauma. Radionuclide angiographic (RNA) imaging was performed as soon as possible after admission and Holter monitors were applied for 72 hours. Routine investigations included serial cardiac enzyme measurements and 12-lead electrocardiograms. Dysrhythmias were classified and ventricular dysrhythmias were stratified by ventricular ectopic score (VES) as ventricular tachycardia (4) or greater than 100 premature ventricular contractions (PVCs)/hour (3). Three hundred twelve patients were entered into the study. Analysis of dysrhythmias revealed 18 patients with a VES of 4 and nine patients with a VES of 3; there were no serious consequences. The most significant dysrhythmia as a marker of outcome was atrial fibrillation (n = 9); five of these patients died, but all of associated noncardiac injuries. A review of abnormal RNAs revealed that all associated mortalities were attributed to noncardiac injuries. A review of postmortem reports and hospital records revealed that no deaths were attributed to cardiac failure or dysrhythmia. Thus the incidence of clinically significant dysrhythmias or other cardiac complications resulting from blunt trauma to the heart may be overestimated.

Wives of Institutionalized Elderly Men: The First Stage of the Transition to Quasi-Widowhood

Abstract: Although much recent research has focused on family caregivers to the community-dwelling impaired elderly, little research has examined the experiences of family caregivers once the older relative ...

Importance of orthotopic transplantation procedures in assessing the effects of transfected genes on human tumor growth and metastasis.

Abstract: Assessment of the function of putative dominantly-acting oncogenes or recessive tumor-suppressor genes in human tumor development and progression must ultimately involve xenografting experiments using immune deficient animals such as nude mice. Most human tumor xenograft experiments have employed conventional subcutaneous injection procedures. However, despite the simplicity of this procedure, it poses some serious potential drawbacks as most types of human tumor will not readily grow or metastasize from a subcutaneous (‘ectopic’) site of injection. In contrast, ‘orthotopic’ injection procedures will often enhance the tumorigenic and/or metastatic ability of tumor cell populations. An example of this is summarized in the context of human malignant melanoma where the effects of subcutaneous versus subdermal injection are compared. Despite the seeming subtle and minor change in injection site, superior growth of human melanomas can be obtained by the latter, orthotopic-like, route of injection. It therefore follows that induction of tumorigenic or metastatic properties in a given human cell population by gene transfection may not be detected if the transfected cells are assayed in vivo only by subcutaneous injection procedures. An example of this is provided by experiments involving transfection of normal or mutated ras genes into a low-grade, well-differentiated human bladder carcinoma cell line, called RT-4. Thus overexpression of normal or mutated (valine 12) c-H-ras resulted in acquisition of a clinical-like invasive phenotype. However, this was clearly seen only if the cells were injected into the bladders (i.e. ‘intravesically’) of nude mice. In contrast, conventional subcutaneous injection of the high ras expressing transfected RT-4 cell lines did not reveal acquisition of invasive properties: all cell lines grew locally as well-encapsulated tumor masses. It is argued that similar orthotopic injection procedures should be employed when assessing the suppressive effects of various wild-type tumor-suppressor genes on human tumor growth in vivo. Utilization of subcutaneous injection procedures may grossly exaggerate the growth suppressive effects of such genes. This could explain the paradox of why, on the one hand, alterations involving many different genes (including different suppressor genes) appear to be involved in human carcinoma tumorigenesis while on the other hand, complete suppression of tumorigenicity can be caused by transfer of a single wild-type suppressor gene. Such complete suppressions might be observed only after ectopic (usually subcutaneous) injection procedures.

Response to desipramine treatment in adolescent major depression.

Abstract: Thirty adolescents (ages 15-20) who met DSM-III-R criteria for major depressive disorder completed a double-blind, placebo-controlled, 6-week, fixed-dose (200 mg daily) study of desipramine (DMI). Thirty-three percent of the placebo group and 50 percent of the DMI group improved (greater than or equal to 50% change on the Hamilton Rating Scale for Depression). Subjective reports of adverse effects did not significantly differentiate the two groups. Major adverse effects, necessitating study discontinuation, occurred solely in the DMI group.