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Biomedical subjects

J Farr

Publications and source records attributed to J Farr.

15 recordsLinked to original sources
PubMed1997

Automatic determination of patellofemoral kinematic parameters through X-ray image processing.

Examination of plain Merchant-view X-rays of the patellofemoral joint is often used to diagnose patellofemoral joint malalignment and to qualify the pathology. As digital image processing becomes more widespread, an image processing algorithm is being developed for medical personnel to easily display, manipulate and analyze digitized plain Merchant-view X-ray films on personal computers. The method provides measurement of the kinematic parameters: sulcus angle (SA), patellofemoral congruence angle (PFC), lateral patellar angle (LPA), patellar rotation angle (PR), and lateral patellar displacement (LPD). Smooth edges of the patella and the femur are obtained by using image enhancement, edge detection and morphological thinning techniques based on the thresholds chosen manually for boundary detection. Six landmarks for determining the kinematic parameters are marked automatically on the edges of patella and femur. Parameter measurements for twelve X-ray films of six patients are calculated for analysis and comparison with hand calculated parameters. The goal is develop an algorithm that can evaluate the geometry of the patellofemoral joint, and is cost effective.

Femur↗
PubMed1996

Assessment of quadriceps muscle performance by hand-held, isometric, and isokinetic dynamometry in patients with knee dysfunction.

One component of patient evaluation is muscle performance assessment. The purpose of this study was: 1) to determine the difference and correlation between hand-held, isometric, and isokinetic dynamometry test results in patients with knee dysfunction and 2) to determine the effect of pain during such testing. Bilateral quadriceps strength in 23 subjects with unilateral knee dysfunction was tested using concentric and eccentric isokinetic dynamometry at 60 degrees/sec, isometric dynamometry, and hand-held dynamometry, both at 60 degrees of knee flexion. Pain ratings were obtained before, during, and after each test. Statistical analysis revealed a significant difference between involved and uninvolved limbs for eccentric isokinetic dynamometry (p = 0.002) and hand-held dynamometry (p = 0.005); no difference was found between limbs for the concentric isokinetic and isometric dynamometry (p > 0.05). Mean percent deficits in quadriceps strength ranged from 11 to 18%, with no significant difference found between testing modes. Pearson product moment correlations ranged from 0.34 to 0.76 when comparing testing modes. No significant difference existed in pain scores before, during, and after each mode of testing. It was concluded that large variation existed between different testing modes, which results in different conclusions regarding the strength of the quadriceps in patients with knee dysfunction.

Adolescent↗
PubMed1993

Lack of variation in the nucleotide sequence corresponding to the transmembrane domain of the beta-amyloid precursor protein in Alzheimer's disease.

The nucleotide sequence corresponding to the APP transmembrane domain and flanking regions of charged amino acids was determined for 91 patients with histologically confirmed Alzheimer's disease, 9 patients with dementias of other etiologies, and 14 controls who had no identifiable brain disease. Twenty-eight of the AD patients had a first-degree relative with dementia. No mutations were detected among the 100 demented patients. However, one of the 14 controls exhibited a change in the 3' base of codon 716 which would not be expected to result in an amino acid substitution at this position.

Alzheimer Disease↗
PubMed1993

Effects of patella taping on patella position and perceived pain.

Anterior knee pain syndrome (AKPS) represents a significant challenge for the sports medicine clinician. One proposed etiological factor for AKPS is poor vastus medialis obliquus (VMO) control, resulting in lateral glide of the patella. Patella taping has been advocated to increase VMO control. The purpose of this study was to determine the effects of patella taping on patella position and perceived pain. Twelve subjects (age = 29 +/- 9 yr; weight = 70.9 kg +/- 17.8; height = 174.0 cm +/- 8.1) with AKPS currently using patella taping procedures with a decrease in their symptoms participated. Each subject had Merchant's view x-rays taken pre- and post-taping while performing an isometric quadriceps contraction to determine patella rotation and patella congruency angles. Subjects also completed a visual analog pain scale after performing a 0.2 m (8") step-down both pre- and post-taping. Paired t-tests revealed no significant change in patellofemoral congruency (P = 0.98) and patella rotation angles (P = 0.80). Significant reduction (50%) in subject pain level was revealed by the visual analog scale (t(15) = 4.99; P < 0.0005). Results demonstrate that patella taping significantly reduced the perceived pain levels during a 0.2-m step-down; however, this reduction in pain was not associated with patella position changes.

Adult↗
PubMed1992

Clinically-silent mutation in the putative iron-responsive element in exon 17 of the beta-amyloid precursor protein gene.

Three missense mutations in exon 17 of the beta-amyloid precursor protein (APP) gene have been reported to cosegregate in families with early onset Alzheimer's disease (AD). All three mutations result in amino acid substitutions at codon 717 and may produce AD by altering the structure of the transmembrane domain of APP. Alternatively, the mutations may destabilize the stem of a putative iron-responsive element (IRE) in which they lie and confer pathogenicity by inactivating this negative regulatory element. We have detected a clinically-silent mutation in codon 716 that would also be expected to disrupt the putative IRE but results in no amino acid substitution. This result strongly suggests that the missense mutations at codon 717 produce AD by altering the amino acid sequence of APP rather than the IRE. Furthermore, the identification of a clinically-silent mutation among four point mutations that span only three nucleotides of exon 17 suggests that this region may be a mutational "hot" spot.

Alzheimer Disease↗
PubMed1992

Meniscal tears: diagnosis, evaluation, and treatment.

Arthroscopic surgery for treatment of pathologic meniscal lesions has become the most commonly performed orthopaedic procedure in the United States. This article reviews the diagnosis, evaluation, and subsequent treatment of meniscal tears in the knee.

Anterior Cruciate Ligament Injuries↗
PubMed1991

Infection control and the future. Continuing and emerging trends.

One might believe that technological advancements, prophylactic antibiotic therapy, and ambulatory surgical trends would have appreciably altered infection statistics. Unfortunately, although economic pressures have shortened inpatient days and stimulated a major shift to outpatient surgical procedures, these changes did little to reduce surgical wound infection rates. Not only are they occurring more often, in more debilitated patients, but they are also becoming increasingly virulent, difficult, and costly to manage. When one considers the effects of surgical wound infection, and the added expense and inconvenience to both patient and hospital, it is logical to assume that OR nurses will take a proactive role in implementing new methods of prevention. The expanded role of the perioperative nurse specialist has helped to improve the quality of intraoperative care. Many positive clinical and technological changes in medical devices and infection control products have helped patient care. Any technological changes in the future must be made on the basis of a rational plan to improve patient care by decreasing surgical wound infection. Changes will occur on the basis of what is in the best long-range interest of the patient. The challenge for today's OR nurse, the medical community, and the health-care industry is to adapt to the needs of a rapidly changing health-care delivery environment. The future holds great promise. The expertise of the OR nurse, as clinician and manager, will be in greater demand as change continues to challenge professionals.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
PubMed1989

Coding strategies for a single-channel tactile aid.

Measurements have been made on the ability of normally hearing subjects to identify the stressed word in simple sentences, using only tactile information. Vibrotactile stimuli were presented to the distal pad of the second finger via a single vibrator. A range of coding strategies was investigated, voice pitch or speech amplitude being represented as stimulus frequency and/or intensity. Test results show that, even without specific training, subjects can be quite successful in identifying stress patterns. The most effective coding strategies were (i) voice frequency presented as continuously variable stimulus frequency over the range 40-220 Hz, with a correlated modulation of stimulus amplitude, (ii) speech amplitude presented as two discrete levels of stimulus amplitude.

Deafness↗
PubMed1975

The effect of noradrenaline, adrenergic blocking agents, and tyramine on the intrarenal distribution of blood flow in the baboon.

The intrarenal distribution of blood flow in the baboon was measured using the 133xenon clearance technique, and dose-response curves for the various components of renal blood flow were determined during intra-arterial infusions of noradrenaline; the alpha-adrenergic blocking agent, phenoxybenzamine; the beta-adrenergic blocking agent, propranolol; and tyramine which causes the release of endogenous NA. High doses of noradrenaline reduced flow in the outer cortex; this effect was attenuated by phenoxybenzamine, but not by propranolol. Tyramine had no effect. These r results suggest that there are alpha-adrenergic receptors in the resistance vessels of the kidney but are inconsistent with an important role for NA-mediated autonomic control of renal blood flow.

Animals↗
PubMedDate not supplied

Telephone advice nurse: identifying critically-ill patients.

Patients who are admitted to Intensive Care Units (ICUs) have usually been critically ill at home first. The telephone advice nurse may be the first person they contact for help when they get sick. This nurse has to distinguish rapidly between critical and non-critical patients. You might find this role a challenging career option.

Acute Disease↗
PubMedDate not supplied

Prophylactic knee braces for football: do they work?

Knee injuries in athletics are a major problem facing the sports medicine community. There is no compelling evidence to suggest that the likelihood of sustaining a knee injury is increasing; however, more knee injuries are being identified and treated due to improved diagnostic techniques. Successful prevention of knee injuries with prophylactic braces has not paralleled the substantial advances in diagnosis and treatment of these knee problems. This article summarizes the current data available and makes recommendations for subsequent prophylactic knee brace use.

Braces↗