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Biomedical subjects

K A Kirby

Publications and source records attributed to K A Kirby.

At least 19 recordsLinked to original sources
PubMed2006

Body mass index, physical activity, and risk of renal cell carcinoma.

OBJECTIVE: To investigate the association between obesity and risk of renal cell carcinoma and to examine whether the association is modified by physical activity. SUBJECTS: A population-based case-control study of 406 patients with renal cell carcinoma and 2434 controls conducted in Iowa. METHODS: Information was collected on weight at the ages 20-29, 40-49, and 60-69 years, height, nonoccupational physical activity, diet, and other lifestyle factors. Renal cell carcinoma risk was estimated by odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for age, total energy intake, and other confounding factors. RESULTS: Height and total energy intake were not associated with risk in either sex. In men, neither physical activity nor level of obesity in any period of life was significantly associated with risk. In women, lower physical activity was associated with higher risk (OR=2.5; 95% CI=1.2-5.2 comparing exercise <1 time/month to >1 time/day). Compared with women in the lowest quartile for BMI, the risks of renal cell carcinoma for women in the highest 10% of BMI in their 20s, 40s, and 60s were 1.4 (CI=0.6-3.1), 1.9 (CI=0.9-4.2), and 2.3 (CI=0.9-6.0), respectively. When analyses were limited to self-respondent data, the corresponding ORs were 2.9 (CI=1.2-7.4), 3.2 (CI=1.3-7.5), and 2.1 (CI=0.7-6.4), respectively. There was little evidence that physical activity modifies the association of BMI with renal cell carcinoma. CONCLUSION: Nonoccupational physical activity was inversely associated and obesity was positively associated with risk of renal cell carcinoma among women. The risk appeared to be greater for women in the highest 10% of BMI in their 40s. Our finding of little evidence of an interaction between physical activity and BMI requires confirmation.

Adult↗
PubMed2006

Clinical and radiologic factors associated with pulmonary nodule etiology in organ transplant recipients.

Identifying clinical and radiographic factors that are associated with a specific etiology of pulmonary nodules (PNs) in solid-organ transplant (SOT) recipients might be helpful in guiding empiric therapy. Multivariable logistic regression was used to assess the relationship of clinical and radiographic variables to the etiology of PN in a retrospectively identified cohort of SOT recipients at a single transplant center. PNs in 55 SOT recipients (lung 15%, heart 22%, liver 42%, kidney 18% or kidney/pancreas 5%) were diagnosed at a mean of 1061 days post-transplant and were infectious in 31 of 55 (56%) (bacterial 22%, fungal 33%, viral 2%) and noninfectious in 24 of 55 (44%) [post-transplant lymphoproliferative disorder (PTLD) 25%, carcinoma 18%]. Radiographic 'consolidation' was independently associated with an infectious etiology (OR, 20.2, p < 0.01). Epstein-Barr virus seronegativity and lung transplant were each associated with PTLD (OR, 21.7, p < 0.01) and (OR, 36.6, p < 0.001), respectively. Diagnosis less than 90 days post-transplant was associated with Aspergillus infection (OR, 12.9, p = 0.007). Specific clinical and radiographic features are associated with specific etiologies of PNs in SOT recipients and might be useful for guiding empiric therapy while awaiting results of definitive diagnostic studies.

Adult↗
PubMed2001

Subtalar joint axis location and rotational equilibrium theory of foot function.

A new theory of foot function based on the spatial location of the subtalar joint axis in relation to the weightbearing structures of the plantar foot is proposed. The theory relies on the concept of subtalar joint rotational equilibrium to explain how externally generated forces, such as ground reaction force, and internally generated forces, such as ligamentous and tendon tensile forces and joint compression forces, affect the mechanical behavior of the foot and lower extremity. The biomechanical effect of variations among individuals in the spatial location of the subtalar joint axis are explored, along with their clinical consequences, to offer an additional theory of foot function, which may improve on existing podiatric biomechanics theory.

Biomechanical Phenomena↗
PubMed2001

What future direction should podiatric biomechanics take?

With researchers from many scientific and medical disciplines currently devoting countless hours trying to solve the mechanical mysteries of the foot, it is important that the proper direction for research be established. The author of this article believes that one of the most important directions in podiatric biomechanics will focus on the development of accurate models of the human foot and lower extremity. Accurate models will be useful because they provide relatively accurate predictions of the magnitudes of loading forces that occur in the structural component of the human foot and lower extremity during weight-bearing activities. From its beginnings in the early 1960s, podiatric biomechanics has developed from a fledgling collection of thoughts and observations from Merton Root and his colleagues to an internationally recognized clinical science with numerous researchers, past and present, contributing to its growing base of knowledge. With an emphasis on accurate modeling of the foot and lower extremity to allow better prediction of the internal forces that create pathologic conditions during weight-bearing activities, podiatric biomechanics will continue to provide valuable insight into many of the painful syndromes that plague children and adults of the world.

Biomechanical Phenomena↗
PubMed2000

Biomechanics of the normal and abnormal foot.

The foot is an engineering marvel that allows the body to perform many physical activities over a wide variety of terrain with remarkable efficiency. The functions of the foot and the lower extremity are biomechanically integrated; thus normal lower-extremity function requires normal foot function and vice versa. Because the subtalar joint is the main pedal joint allowing the triplanar translation of motion between the foot and lower extremity, normal subtalar joint function is critical to normal foot and lower-extremity function. This article provides an overview of the interrelationships between foot and lower-extremity function and mechanically based pathology of the foot and lower extremity, with an emphasis on the subtalar joint.

Biomechanical Phenomena↗
PubMed1995

Intraluminal ultrasound-guided biopsy of the prostate: case report.

Patients who have undergone proctectomy can present a difficult diagnostic challenge for the urologist, as digital rectal examination and transrectal ultrasound scanning are not possible. Various methods have been tried to biopsy the prostate in patients without rectums and have proved to be limited in their usefulness. Intraluminal ultrasound employs a small high-frequency probe that creates an image from an intraluminal perspective. We describe a new role for this imaging method in which intraurethral intraluminal ultrasound scans can be used to guide perineal prostate biopsies in the patient without a rectum.

Aged↗
PubMed1995

Distal ureteral stone in a duplicated system causing urinary retention.

Ureteral calculi and urinary retention are common problems encountered by the urologist. However, they rarely occur concomitantly. Herein, we describe a case of a 40-year-old female patient who developed urinary retention as a result of ureteral stone disease. Specifically, an ectopic upper pole ureter in a completely duplicated system contained a 2 x 6-cm ureteral stone, which emanated from the orifice, filling the urethra. The stone caused voiding difficulties to the extent that the patient had to manipulate the stone manually in order to void. The stone eventually resulted in urinary retention. Management was accomplished by cystoscopy and electrohydraulic lithotripsy of the stone. Chemical analysis revealed calcium phosphate and struvite as the principal components of the stone.

Adult↗
PubMed1994

Fixed drug eruption to papaverine.

Papaverine has offered new options for therapy in erectile dysfunction. Various complications have been reported with papaverine, the prominent ones being priapism and liver function abnormalities. We present a previously unreported case of a fixed drug eruption caused by papaverine.

Drug Eruptions↗
PubMed1992

The effect of lower-limb anatomy on knee loads during seated cycling.

Overuse knee joint injuries are the primary injuries to cyclists. Overuse injuries have been intuitively linked to the anatomic structure of the foot because external loads are applied to the foot in cycling. Thus, the structure and function of the foot should dictate in part how the loads are transmitted to the knee joint. Therefore, it was hypothesized that patterns in knee loads are related to the anatomic structure of the foot. To test this hypothesis, peak knee loads (dependent variables) were related to anatomical variables (independent variables) through statistical analyses. This required first the detailed evaluation (i.e. measurement) of the anatomical structure of the foot and leg for 23 subjects. Next, three-dimensional knee joint loads were determined for a standardized riding condition. The results of the statistical analyses indicated that a group of cyclists with the most extreme inversion of the forefoot relative to the transverse plane developed significantly greater average posterior knee force and extensive knee moment. In addition, a number of anatomical variables significantly accounted for the variability in peak values of the posterior force, the extensive moment, the varus/valgus moment and the external axial moment. Based on these results, the hypothesis is accepted.

Adult↗
PubMed1992

The medial heel skive technique. Improving pronation control in foot orthoses.

A new method of foot orthosis modification that enhances the pronation controlling ability of foot orthoses is presented. The medial heel skive technique involves selectively removing small amounts of the medial portion of the plantar heel of the positive cast of the foot to create a unique varus wedging effect within the heel cup of the foot orthosis. The resulting increase in supination moment across the subtalar joint axis of the foot clinically produces significantly improved pronation control on pediatric flexible flat feet, posterior tibial dysfunction, and other types of excessively pronated feet.

Biomechanical Phenomena↗
PubMed1989

Rotational equilibrium across the subtalar joint axis.

A review of the rotational forces, or moments, acting across the subtalar joint axis during relaxed bipedal stance is presented. The concept of rotational equilibrium about the subtalar joint axis is used to explain some of the biomechanical differences between feet that stand in the neutral and maximally pronated subtalar joint positions. In addition, the mechanical basis of treatment of sinus tarsi syndrome with foot orthoses using the concepts of subtalar joint axis moments rotational equilibrium of the subtalar joint is presented.

Biomechanical Phenomena↗