Methodologies to examine the importance of host factors in bioavailability of metals

Bioavailability provides a link between intrinsic toxicity and the ability to produce that toxic effect in an organism. Biomonitoring tools are essential to assess the health of ecosystems and their component parts, including humans. While field and laboratory data are available, two critical issues to our understanding of bioavailability are often missing: 1) knowing the relationship between dose and tissue concentrations, and 2) species extrapolations. Understanding of high to low dose extrapolation is also critical. Methods to understand the importance of host factors in bioavailability of metals must assess gender, age, nutritional status, individual variability, temporal changes, and critical habitat effects. Methods to examine these variables include correlational, observational, experimental, epidemiological, and modeling studies, or a combination of these. Data gaps include developing more representative studies of human and animal populations, better analytical tools for rapid determination of metal content in the field, improved analytical characterization of metal bioavailability, and concurrent studies of different metals.     

Institutioning a clinical practice guideline to decrease the rate of normal appendectomies

With the advent of laparoscopic appendectomy, the rate of normal appendectomies increased at our institution. To decrease our rate of normal appendectomies, we instituted a clinical practice guideline in January 1999 for the preoperative evaluation and treatment of patients with possible acute appendicitis. The medical records of 464 consecutive patients who underwent either open or laparoscopic appendectomy with a preoperative diagnosis of acute appendicitis between January 1, 1997, and December 31, 2000, were reviewed. The decision of open versus laparoscopic appendectomy was made at the time of surgery by the attending surgeon. Two hundred twelve patients (116 females, 96 males) underwent an appendectomy for acute appendicitis (142 open, 70 laparoscopic) from January 1, 1997 through December 31, 1998, prior to the institution of the guideline. Two hundred fifty-two patients (117 females, 135 males) underwent an appendectomy for acute appendicitis (193 open, 59 laparoscopic) from January 1, 1999, through December 31, 2000 (after the guideline was instituted). Prior to the guideline, the normal appendectomy rate was 21.7 per cent (18.3% open, 28.6% laparoscopic). After the guideline was instituted, the normal appendectomy rate was 16.7 per cent (14.5% open, 23.7% laparoscopic). In females, the normal appendectomy rate prior to the guideline was 31.0 per cent (26.6% open, 36.5% laparoscopic) while the normal appendectomy rate after the guideline was 23.1 per cent (19.0% open, 31.6% laparoscopic), P = 0.172. In males, the normal appendectomy rate prior to the guideline was 10.4 per cent (11.5% open, 5.6% laparoscopic) while the normal appendectomy rate after the guideline was 11.1 per cent (11.4% open, 9.5% laparoscopic), P = 0.861. By instituting a guideline for the diagnosis and treatment of possible acute appendicitis, we were able to decrease our rate of normal appendectomies. Although statistical significance was not reached, there is a trend toward decreasing the rate of normal appendectomies in females after the guideline was instituted.     

Combined video-assisted thoracoscopic lung volume reduction surgery and lobectomy in a high-risk patient

Nonsmall cell lung cancer often occurs in patients with severe emphysema. Lobectomy in these patients is often contraindicated due to extensive parenchymal destruction and subsequent pulmonary insufficiency. Video-assisted thoracoscopic lobectomy has been described as a less morbid procedure in high-risk patients. Lung volume reduction surgery has been shown to improve pulmonary function in selected patients with emphysema. We describe the successful combination of lobectomy and lung volume reduction surgery (LVRS) with a video-assisted thoracoscopic (VATS) approach in a high-risk patient with Stage I nonsmall cell lung cancer.     

Imaging the painful hip

With the advent of magnetic resonance imaging and, subsequently, magnetic resonance arthrography, the imaging algorithm for hip pain has evolved considerably. Magnetic resonance imaging has supplanted bone scintigraphy as the first line imaging test after conventional radiographs in the setting of suspected occult fracture, transient marrow edema, and osteonecrosis. Computed tomography scanning and magnetic resonance imaging are invaluable for the evaluation of monarticular arthropathies such as pigmented villonodular synovitis and synovial osteochondromatosis. By combining conventional magnetic resonance imaging with capsular distention afforded by arthrography, magnetic resonance arthrography has become the imaging examination of choice for disorders of the acetabular labrum and for the evaluation of articular cartilage at the hip.     

Exercise in hot and cold environments: differential effects on leukocyte number and NK cell activity

INTRODUCTION: Exercise and environmental temperature have been reported to affect the immune system, but few studies have examined the combined effects of very hot or cold temperatures during exercise in the same group of subjects. Therefore, the purpose was to examine the immune responses following exercise combined with exposure to hot and cold environments. METHODS: There were 10 men who completed 2 60-min cycle ergometry (60% VO2peak) trials: hot (HT: 38 degrees C, 45% RH) and cold (CD: 8 degrees C, 50% RH). Rectal core temperatures (Tc), average skin temperatures (Tsk), and HR were recorded every 15 min of exercise. Venous blood was collected before (PRE), immediately after (POST), 2 h after (2 h), and 24 h after exercise (24 h). Physiologic strain index (PSI) was calculated. Total and differential leukocytes were determined by manual counting (adjusted for plasma volume shifts). Natural killer cell activity (NKCA) was determined by a whole blood 51Cr-release assay. RESULTS: Tsk, Tc, and PSI were significantly lower in the CD than HT trial (p < 0.05). Total leukocyte count was greater POST (40%) and 2 h (74%) than PRE and 24 h in both conditions (p < 0.05). Neutrophil count was greater POST (49%) and 2 h (132%) than PRE and 24 h in both conditions (p < 0.05). Lymphocyte count was greater POST (24%) in HT than CD (p < 0.05). NKCA was greater POST (38%) than PRE, 2 h, and 24 h in both conditions (p < 0.05). HT caused significant increases for Tc and Tsk above those observed for CD (p < 0.05). PSI was greater in HT (9.92 +/- 0.93) than CD (4.24 +/- 0.56) (p < 0.05). DISCUSSION: Exercise in HT produced more physiological stress than CD; however, this difference was not manifested in the immune system response. Heat and cold stress in combination with exercise produce similar disturbances in immunity during recovery from exercise.     

Developments in instrumentation for emission computed tomography

Instrumentation for emission computed tomography continues to evolve, taking advantage of developments in detector technology, data processing and correction methods, and reconstruction algorithms. This article reviews the basic principles and latest developments in emission computed tomography instrumentation, for both positron emission tomography and single-photon emission computed tomography applications.     

Nonaltruistic kidney donations in contemporary Jewish law and ethics

BACKGROUND: In 2000, the Consensus Statement on the Live Organ Donor reported that "direct financial compensation for an organ from a living donor remains controversial and illegal in the United States" and took note of the position of the Transplantation Society that "Organs and tissue should be given without commercial consideration or commercial profit." Christian authorities insist that organ donors must not accrue economic advantage, and "selling" organs deprives the donation of its ethical quality. METHODS: The writings of major contemporary authorities of Jewish law and ethics whose halakhic positions on bioethical issues are regularly considered by Orthodox, Conservative, and Reform ethicists were reviewed. Their positions on this issue were contrasted with those of various contemporary secular and religious authorities. RESULTS: These Jewish authorities reject the notion that generosity and charity, rather than monetary gain and greed, must serve as the exclusive basis for donation of functioning organs. CONCLUSION: Although nonaltruistic sale of kidneys may be theoretically ethical, ultimately its ethical status in Jewish ethics and law is inextricably connected to solving a series of pragmatic programs, such as creating a system that ensures that potential vendors and donors are properly informed and not exploited. Lacking such arrangements, ethical nonaltruistic kidney donations remain but a theoretical possibility.     

Palliative irradiation of the spleen

We analyzed the efficacy of splenic irradiation in a population of patients with hematologic diseases. The records of the Radiation Oncology Division, Naval Medical Center San Diego were retrospectively reviewed for all patients treated with splenic irradiation (SI) between January 1, 1990 and March 1, 2001. The charts of 17 patients were identified: 5 patients had chronic myelogenous leukemia, 4 had chronic lymphocytic leukemia, 4 had idiopathic myelofibrosis, 2 had polycythemia vera, and 1 patient each had idiopathic thrombocytopenic purpura and acute myelogenous leukemia. Patient ages ranged from 37 to 88 years. Sixteen of 17 suffered from symptomatic splenomegaly. Twenty-six courses of splenic irradiation were delivered to these 17 patients. Treatment courses generally consisted of two fractions of 50 cGy in the first week, two fractions of 75 cGy the second week, and two fractions of 100 cGy the third week. Blood counts were checked prior to each treatment. Seven of the 17 patients died 1 month or less after SI due to the terminal nature of their disease. Twenty-two of 25 treatment courses for splenomegaly resulted in decreased pain and symptoms. Five patients required two treatment courses for splenomegaly, and one patient required five treatment courses. Three of four patients treated for thrombocytopenia demonstrated improvement, but only one was evaluable for more than 2 weeks due to disease-related mortality. Three of five patients treated for leukocytosis had significant improvement. In general, patients suffered few significant complications from this palliative intervention. Splenic irradiation can effectively palliate symptomatic splenomegaly in patients for whom splenectomy is not an option. Retreatment is possible. Splenic irradiation is less effective in the treatment of thrombocytopenia or leukocytosis.