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Biomedical subjects

Barry M Wall

Publications and source records attributed to Barry M Wall.

10 recordsLinked to original sources
PubMed2007

Osteomalacia and secondary hyperparathyroidism after kidney transplantation: Relationship to vitamin D deficiency.

Secondary hyperparathyroidism is highly prevalent in patients with end-stage renal disease. After successful kidney transplantation, however, parathyroid glands gradually involute to normal size with subsequent normalization of intact parathyroid hormone (PTH), serum calcium, and phosphorous concentrations. This report describes a 48-year-old diabetic end-stage renal disease patient who underwent a successful cadaveric kidney transplant. Serum calcium and phosphorous concentrations normalized within 6 months. Three years later, he presented with complaints of proximal muscle weakness that was progressively worsening. Physical examination revealed temporal wasting and proximal muscle weakness. Detailed neurologic examination was unremarkable except for decreased vibratory sensation in both feet. Laboratory data showed stable allograft function (serum creatinine, 1.3 mg/dL), hypocalcemia, and hypophosphatemia with markedly elevated alkaline phosphatase level (726 IU/L) and intact PTH level (947 pg/mL). Further laboratory evaluation revealed poor nutritional status and severe deficiency of 25(OH)D (4.0 ng/mL). Past medical history included remote episodes of acute pancreatitis due to prior alcohol abuse. Computed tomography of the abdomen showed calcific atrophic pancreas, and steatorrhea was confirmed on stool studies. Decreased bone mineral density was noted by computed tomography bone density scan. Secondary hyperparathyroidism and osteomalacia had developed due to severe vitamin D deficiency, occurring as a result of previously unrecognized, minimally symptomatic pancreatic exocrine insufficiency. Treatment with vitamin D, calcium, and pancreatic enzyme replacement led to remarkable resolution of clinical symptoms and secondary hyperparathyroidism (intact PTH, 65 pg/mL after therapy) and resulted in significant improvement in bone mineralization. Factors associated with vitamin D deficiency in the chronic kidney disease and post-transplant patient population are reviewed.

Abdominal Cavity↗
PubMed2006

Effect of timed semirecumbency and furosemide dosing on urinary sodium excretion in patients with compensated heart failure.

PURPOSE: The management of chronic cardiac failure, a salt-sensitive state, frequently includes administration of a loop diuretic to enhance urinary Na excretion. We hypothesized that a period of timed semirecumbency (vis-à-vis upright posture) would enhance the natriuresis that accompanies oral furosemide dosing in patients with compensated cardiac failure. METHODS: Four ambulatory patients with compensated chronic cardiac failure (NYHA Class III) of ischemic and nonischemic origin and systolic dysfunction (ejection fraction <35%), who were receiving a stable regimen of oral furosemide and angiotensin-converting enzyme inhibitor, were enrolled into the study. In the institution's Clinical Research Center, we monitored and compared urine flow rate (mL/min) and Na excretion rate (mEq/hr) in each patient in response to two different protocols. Protocol 1 consisted of an initial 90-minute period of bedrest followed by the patient's oral furosemide dose and 180 minutes of upright activity and a subsequent 90-minute period of bedrest. Protocol 2 was similar, with the exception that furosemide dosing was given after upright activity and immediately prior to the second period of bedrest. RESULTS: With each patient serving as his or her own control, both urine flow rate and urinary Na excretion rate were markedly increased when furosemide was given prior to bedrest as compared to its dosing prior to upright activity. CONCLUSIONS: In patients with compensated chronic cardiac failure, the natriuresis that accompanies oral furosemide dosing is enhanced when given just prior to a period of timed semirecumbency. This approach represents a more optimal use of this loop diuretic in patients with compensated heart failure.

Adult↗
PubMed2004

Medial arterial calcification mimicking temporal arteritis.

Medial arterial calcification, which has been increasingly recognized in end-stage renal disease (ESRD) patients, has been associated with acutely symptomatic vascular complications including calcific uremic arteriolopathy (calciphylaxis) and ischemic changes in the extremities. This report describes a 50-year-old ESRD patient on maintenance hemodialysis in whom medial arterial calcification developed with features mimicking the findings of temporal arteritis. He complained of persistent bilateral temporal area headaches with associated symptoms of blurred vision; pain in his shoulders, hips, and knees; and intermittent symptoms consistent with jaw claudication. He was not receiving calcium or vitamin D supplements. Superficial temporal arteries were dilated, tortuous, nodular, and tender to palpation. Ophthalmologic examination was unremarkable, except for the presence of peripapillary atrophy. Temporal artery biopsy results showed medial arterial calcification with mild inflammatory changes. No giant cells were identified. Additional long-term complications of medial arterial calcification have included the development of painful ischemic ulceration of the glans penis and extensive mitral annulus calcification detected by echocardiography. The findings in this patient show that clinical manifestations of medial artery calcification associated with ESRD can mimic those seen with other vascular diseases.

Arteriosclerosis↗
PubMed2003

Bacteremia in the chronic spinal cord injury population: risk factors for mortality.

BACKGROUND: Individuals with spinal cord injury (SCI) have a lifelong increased risk of systemic infection, which may be associated with episodes of life-threatening bacteremia. Information concerning specific organisms causing bacteremia, the sites of primary infection, and clinical predictors for mortality are necessary to provide optimal treatment. METHODS: A retrospective review of positive blood cultures collected over a 32-month period in chronic SCI patients treated at the Veterans Affairs Medical Center SCI Unit. RESULTS: One hundred and twenty-three episodes of bacteremia occurred in 63 patients during 83 hospitalizations; 30 patients had multiple episodes of bacteremia. There were 1,644 admissions during this period, yielding an incidence of bacteremia of 7.5% (5.8% after excluding positive cultures that were believed to be caused by contaminants). The patients (31 with paraplegia and 32 with quadriplegia) had a mean age of 59 +/- 2 years, and a mean duration of injury of 23 +/- 2 years. Bladder management technique consisted of indwelling bladder catheter (n = 53), ileal conduit (n = 6), intermittent catheterization (n = 2), and spontaneous voiding (n = 2). Episodes of bacteremia were nosocomial in 89 out of 123 episodes. Multiple debilitating factors were present, including pressure ulcers in 36 out of 63 patients, chronic ventilator dependency in 5 out of 63 patients, recent surgical procedures in 17 out of 63 patients, underlying malignancy in 5 out of 63 patients, and evidence of malnutrition in 29 out of 63 patients (serum albumin concentration < 2.5 g/dL). Early mortality rate (death within 30 days of bacteremia) occurred in 8 out of 63 patients (13%) and late mortality (> 1 month following a bacteremic episode) occurred in 10 additional participants, such that total mortality was 1 8 out of 63 (29%). The sources of bacteremia were urinary tract infection (n = 39), presumed contaminant (n = 28), decubitus ulcers (n = 21), intravascular catheter (n = 19), pneumonia (n = 5), and other (n = 11). Gram-negative rods accounted for 26 out of 39 episodes of bacteremia from a urinary source. Methicillin-resistant Staphylococcus aureus, methicillin-sensitive S aureus, and coagulase-negative staphylococci were the predominant organisms when intravascular catheters or pressure ulcers were the source of bacteremia. CONCLUSION: In this population, bacteremia predominantly was caused by hospital-associated organisms, and occurred mainly in malnourished patients who required hospitalization for major underlying debilitating conditions, particularly pressure ulcers. Chronic indwelling bladder catheters and chronic vascular catheter usage also were highly prevalent in patients with bacteremic episodes. Hypoalbuminemia was the strongest independent predictor for mortality.

Bacteremia↗
PubMed2002

Renal pathology resulting from PGHS-2 gene ablation in DBA/B6 mice.

Kidneys of prostaglandin H synthase-2 (PGHS-2) null mice fail to develop normally, leading to renal insufficiency. We have found that in a mixed DBA/B6 background, the lack of a functional PGHS-2 gene causes less severe renal pathology than was reported previously for PGHS-2 null mice in a B6 genetic background. The increase in blood urea nitrogen in the DBA/B6 strain of PGHS-2 null mice was significantly lower than reported for B6 PGHS-2 null mice (200% versus 270%). Cystic changes in DBA/B6 PGHS-2 null mice were also less severe. The DBA/B6 PGHS-2 null adult mice did not die from renal failure, unlike their B6/PGHS-2 counterparts that showed excessive neonatal and adult deaths. Therefore, DBA/B6 PGHS-2 null may be highly suitable to study the functional consequences of the lack of PGHS-2 in the kidney due to their less severe pathology and greater survival.

Animals↗
PubMed2002

Differences and similarities between patients with and without end-stage renal disease, with regard to location of intracardiac calcification.

It has been known for some time that mitral annulus calcification is common in end-stage renal disease (ESRD) patients on long-term dialysis, as well as in elderly patients without renal failure. However, a systematic comparison of cardiac calcification in these two types of patients has not yet been made. We examined two-dimensional echocardiograms in 33 patients with ESRD (mean age 66 +/- 10 years) and in 34 other patients with intracardiac calcification but no ESRD (mean age 69 +/- 9 years), with particular attention to precise anatomic location of calcification. Age was not significantly different in the two groups. The incidences of posterior mitral annulus calcification and aortic valve calcification were not significantly different in the ESRD and non-ESRD groups, though mitral annulus calcification tended to be larger in ESRD patients. Basal mitral leaflet calcification and papillary muscle calcification was much more common in the ESRD group. Calcification of intervalvar fibrosa and of tricuspid annulus were noted only in ESRD patients.

Aged↗
PubMedDate not supplied

CHF: circulatory homeostasis gone awry.

The role of the renin-angiotensin-aldosterone system (RAAS) is integral to salt and water retention, particularly by the kidneys. Over time, positive sodium balance leads first to intra- and then to extravascular volume expansion, with subsequent symptomatic heart failure. This report examines the role of the RAAS in regulating a less well recognized component essential to circulatory homeostasis--central blood volume. The regulation of central blood volume draws on integrative cardiorenal physiology and a key role played by the RAAS in its regulation. In presenting insights into the role of the RAAS in regulating central blood volume, this review also addresses other sodium-retaining states with a predisposition to edema formation, such as cirrhosis and nephrosis.

Blood Circulation↗
PubMedDate not supplied

The role of real-time ultrasound and physical examination measurements in placement of cuffed-tunneled hemodialysis catheters.

The portability of non-invasive ultrasound has resulted in an expansion of its utilization into a variety of clinical settings. Since ultrasound is recommended for initial vein cannulation during catheter placement, it is conceivable that ultrasound may also be used to verify catheter position. The purpose of this study was to evaluate the feasibility of tunneled hemodialysis catheter placement without the use of fluoroscopy. Determination of appropriate catheter length using physical exam measurements and verification of correct placement using portable ultrasound were examined. A total of 61 subjects, 31 with and 30 without a tunneled hemodialysis catheter underwent echocardiographic examination using the SonoSite 180PLUS (HCU; Bothell, WA) portable ultrasound. The investigator, using dynamic ultrasound imaging, was able to identify correct position in 30 of the 31 subjects with catheters. Still echocardiographic images were reviewed by two cardiologists and determined to be inconclusive. Physical examination measurements correlated well with the interventional radiologist guide-wire measurements (p < .01; r = 0.65) and concluded to be a useful method for determining appropriate cuffed catheter length.

Body Mass Index↗