Effects of chronic manganese exposure on attention and working memory in non-human primates.

Manganese (Mn) is essential for a variety of physiological processes, but at elevated levels, can be neurotoxic. While cognitive dysfunction has been recently appreciated to occur as a result of chronic Mn exposures, it is still unclear as to which cognitive domains are most susceptible to disruption by Mn exposure. We previously described early appearing Mn-induced changes in performance on a paired associate learning task in monkeys chronically exposed to Mn and suggested that performance of this task might be a sensitive tool for detecting cognitive dysfunction resulting from Mn exposure. As chronic Mn exposure has been suggested to be associated with attention, working memory and executive function deficits, the present study was conducted to assess the extent to which detrimental effects of chronic Mn exposure could be detected using tasks specifically designed to preferentially assess attention, working memory, and executive function. Six cynomolgus monkeys received Mn exposure over an approximate 12 month period and three served as control animals. All animals were trained to perform a self-ordered spatial search (SOSS) task and a five choice serial reaction time (5-CSRT) task. Deficits in performance of the SOSS task began to appear by the fourth month of Mn exposure but only became consistently significantly impaired beginning at the ninth month of Mn exposure. Performance on the 5-CSRT became significantly affected by the third month of Mn exposure. These data suggest that in addition to the paired associate learning task, cognitive processing speed (as measured by the 5-CSRT) may be a sensitive measure of Mn toxicity and that brain circuits involved in performance of the SOSS task may be somewhat less sensitive to disruption by chronic Mn exposure.

Chronic manganese exposure impairs visuospatial associative learning in non-human primates.

Manganese (Mn) is an essential trace metal nutrient, however, excess Mn can be neurotoxic. The degree to which chronic environmental or occupational exposures to Mn in adults cause neuropsychological dysfunction is of considerable interest. Descriptions of neuropsychological dysfunction following chronic Mn exposure have been somewhat inconsistent though, likely owing to different measures of exposure in different populations, complicated by factors of mixed exposures and differences in neuropsychological tests administered. We previously described up-regulation of the mRNA expression for amyloid-beta (A-beta) precursor-like protein 1 (APLP1) and the presence of A-beta diffuse plaques in frontal cortex of Mn-exposed monkeys. The present study examined Mn-induced changes in performance on a paired associate learning (PAL) task that has been suggested as a marker for preclinical Alzheimer's disease. Aspects of performance of this task were affected early following initiation of Mn exposure. Thus, PAL performance may be a sensitive and valuable tool for the early, preclinical detection of incipient dementia and it may also be a sensitive tool for detecting cognitive dysfunction from Mn exposure. The current cognitive data, combined with our previous findings, suggest that frontal cortex may be a particularly sensitive target for the effects of Mn on cognition and that chronic Mn exposure may initiate or accelerate a process that could lead to or predispose to Alzheimer's like pathology and cognitive dysfunction.

Packed red blood cell age does not impact adverse events or outcomes after subarachnoid haemorrhage.

OBJECTIVES: To determine if the age of packed red blood cells (PRBCs) is associated with adverse events or outcomes in patients with subarachnoid haemorrhage (SAH). AIM: Analyse data on PRBC age to complications and outcomes in patients with SAH. BACKGROUND: Patients who receive a PRBC transfusion after SAH have a higher rate of complications, and older PRBC age may be responsible for this. METHODS/MATERIALS: We prospectively recorded clinical and demographic data, acute adverse effects related to transfusion, major hospital events, radiographic cerebral infarction, PRBC age and outcomes in 119 patients with SAH who received a PRBC transfusion. Patients were followed for outcomes at 14 days or discharge, 28 days and 3 months with the modified Rankin scale (a measure of neurologic function). RESULTS: In 241 PRBC transfusions, there was new fever in 36 (15%), hypotension in 23 (10%), pulmonary oedema or symptomatic respiratory distress in 5 (2%) and rash in 1 (1%). Age of PRBCs administered was not associated with vasospasm, cerebral infarction, acute adverse events or outcomes (P > 0·1 for all). CONCLUSIONS: In this small registry of patients with SAH, the age of transfused PRBCs was not associated with adverse events or outcomes.

The value of a hospitalist service: efficient care for the aging population?

BACKGROUND: We studied patients of a hospitalist teaching service and patients receiving routine private care (control subjects). We sought to evaluate whether inpatients cared for by an academic hospitalist service had lower lengths of stay and resource utilization rates. METHODS: Using monthly hospital census data, 477 hospitalist cases and 1,160 control cases were selected by explicit criteria from the Medicaid population of a large, university-affiliated, community medical center between July 1, 1996, and June 30, 1997. Outcomes in hospitalist faculty patients were compared to those of control patients under the care of private providers. RESULTS: Median length of stay was 4 days for control subjects and 3 days for the hospitalist service (p < 0.0001). Median total cost per case was $4,853 for control subjects and $4,002 for hospitalist patients (p < 0.0001). Only patients > or = 65 years old showed statistically significant reductions in both length of stay (p < 0.0001) and total cost (p = 0.002). Subspecialty consultation rates were 37.6% for control subjects and 16.6% for hospitalist cases (p < 0.0001). We noted increasing consultations for patients > or = 65 years old, especially in the control group (p = 0.001). No significant differences in mortality, 30-day readmissions, or interfacility transfers were observed. CONCLUSIONS: Patients cared for by an academic hospitalist service that includes actively participating medical residents appear to have lower lengths of stay, total costs, and consultation rates than patients receiving routine private care. The reductions are largely observed among patients > or = 65 years old.

Ultrasonography performed by primary care residents for abdominal aortic aneurysm screening.

A prospective pilot study was undertaken to assess a protocol to educate primary care residents in how to personally perform ultrasonography for abdominal aortic aneurysm screening. Resident exams were proctored by a primary care physician trained in ultrasonography and were scored on the level of competence in doing the examination. Patients had ultrasound performed by a resident, followed by repeat examination by the vascular lab. Primary care resident abdominal aortic imaging was achieved in 79 of 80 attempts. Four abdominal aortic aneurysms were identified. There were 75 normal examinations; resident ultrasonography results were consistent with the results of the vascular lab. Ten residents achieved an abdominal aortic ultrasound-independent competence level after an average of 3.4 proctored exams. The main outcome of this study is that a primary care resident, with minimal training in ultrasonography imaging, is able to rapidly learn the technique of ultrasonography imaging of the abdominal aorta.

The effect of a new NPO policy on operating room utilization.

STUDY OBJECTIVES: To prospectively assess the impact of a liberalized preoperative fasting policy on operating room (OR) utilization. STUDY DESIGN: Prospective cohort study involving data collection before and after a change in nil per os (NPO) policy. SETTING: Academic teaching hospital. PATIENTS: 5,420 consecutive outpatients and AM admissions. INTERVENTIONS: Data collection was done on all adult patients who presented to our OR suite over two 15-week periods. During the first 15-week period, patients were instructed to drink no liquids after midnight (control group, n = 2,646). In the second 15-week period, patients were allowed to consume unlimited clear fluids until 2 to 3 hours prior to surgery (study group, n = 2,774). MEASUREMENTS AND MAIN RESULTS: We found no difference between the control and study groups in the number of cases cancelled (0 in each group) or delayed (8 vs. 9; relative risk [RR] = 1.07, 95% confidence interval [CI] = 1.000 to 1.148) due to noncompliance with fasting guidelines. There was no difference between the groups in the number of cases of aspiration (0 in each group). In the control group, significantly more episodes of regurgitation were noted (12 vs. 9; RR = 0.715, 95% CI = 0.535 to 0.955) and more rapid-sequence/awake intubations were performed (119 vs. 51; RR = 0.409, 95% CI = 0.306 to 0.546) than in the study group. CONCLUSIONS: Liberalizing a preoperative fasting policy and allowing patients to consume unrestricted clear fluids up until 3 hours before their scheduled time of surgery did not affect their compliance with fasting requirements. No increase in cancellations or delays of surgical procedures due to inappropriate oral intake was observed.

Current millennium biotechniques for biomedical research on parasites and host-parasite interactions.

The development of biotechnology in the last three decades has generated the feeling that the newest scientific achievements will deliver high standard quality of life through abundance of food and means for successfully combating diseases. Where the new biotechnologies give access to genetic information, there is a common belief that physiological and pathological processes result from subtle modifications of gene expression. Trustfully, modern genetics has produced genetic maps, physical maps and complete nucleotide sequences from 141 viruses, 51 organelles, two eubacteria, one archeon and one eukaryote (Saccharomices cerevisiae). In addition, during the Centennial Commemoration of the Oswaldo Cruz Institute the nearly complete human genome map was proudly announced, whereas the latest Brazilian key stone contribution to science was the publication of the Shillela fastidiosa genomic sequence highlythed on a Nature cover issue. There exists a belief among the populace that further scientific accomplishments will rapidly lead to new drugs and methodological approaches to cure genetic diseases and other incurable ailments. Yet, much evidence has been accumulated, showing that a large information gap exists between the knowledge of genome sequence and our knowledge of genome function. Now that many genome maps are available, people wish to know what are we going to do with them. Certainly, all these scientific accomplishments will shed light on many more secrets of life. Nevertheless, parsimony in the weekly announcements of promising scientific achievements is necessary. We also need many more creative experimental biologists to discover new, as yet un-envisaged biotechnological approaches, and the basic resource needed for carrying out mile stone research necessary for leading us to that "promised land" often proclaimed by the mass media.

Percutaneous dilatational tracheostomy: still a surgical procedure.

Although percutaneous dilatational tracheostomy (PDT) has been shown to be a cost-effective bedside alternative to open tracheostomy (OT), prior reports of the complications of the procedure are contradictory. Reported complications range from minor events to fatal ones, in varying percentages. This prospective study was designed to identify the type and severity of complications accompanying the introduction of PDT to a tertiary medical center. Surgical and medical intensive care unit (ICU) patients requiring elective tracheostomy were identified as appropriate for PDT using approved institutional criteria. All procedures were performed at an ICU bedside in the presence of a surgeon privileged to perform OT. Demographic data, procedural information, and patient outcome (including minor and major complications, length of stay, and survival) were collected. PDT was performed in 96 ICU patients, with complete data available for 95 patients. PDT was performed in an average of 13.1+/-1.0 minutes. Twenty-three major and minor complications occurred, including two perioperative deaths, in 15 patients (15.8%). A total of 37 PDT patients (38.9%) died in the hospital, indicative of the severity of illness of patients requiring tracheostomy. Based on the experience to date, Cedars-Sinai Medical Center (Los Angeles, CA) continues to require a surgeon privileged to perform OT to participate in all PDT procedures.

The stuck catheter: a case report.

Complications after the use of central venous catheters have become more frequent as their use in therapy has increased. As a result, the recognition and management of central venous catheters must be emphasized. We describe a unique problem, that of the "stuck catheter," and its safe and simple solution.

Peripherally inserted central catheters in general medicine.

OBJECTIVE: To report the success rate and complications associated with peripherally inserted central venous catheters (PICCs) and to compare costs between PICCs and centrally inserted central catheters. MATERIAL AND METHODS: We undertook a cohort study of the first 1,000 patients referred to the PICC service of a large tertiary-care, university-affiliated, community hospital. The data were analyzed for insertion success rate, insertion mode, complication rate, successful completion, insertion costs, and applicability of PICCs in "high-risk" groups (transplant, human immunodeficiency virus-infected, intensive-care unit, and pediatric populations). RESULTS: Of 1,000 consecutive PICC attempts, 963 (96.3%) were successful. Cutdown procedures were necessary in 141 insertions (14.6%). Complications of PICC placement occurred in 170 cases (17.7%). Among the major complications were a need for multiple attempts at insertion in 92 cases, malpositioning in 56, mechanical phlebitis in 37, clotting in 37, and bleeding in 5. The rate for completion of therapy was 68.9%. Frequent reasons for early termination were dislodgment (in 85 cases) and infection (in 72-37 confirmed and 35 potential cases). The rate of confirmed infection was 11 per 10,000 catheter days. The costs of PICC insertion were less than those associated with centrally inserted central catheters. CONCLUSIONS: PICCs can satisfy long-term vascular needs and are safe in many patient populations. The infection rate did not depend on insertion mode, lumen number, or patient's immune status. Use of total parenteral nutrition was the most important risk factor in all patient subsets. Cost and safety considerations strongly favor PICCs as alternatives to other vascular access devices.

Rapid identification of group A streptococcus as the cause of necrotizing fasciitis.

Group A beta-hemolytic Streptococcus pyogenes (GAS) causes a spectrum of highly aggressive, invasive infections. We report two cases of necrotizing fasciitis in which GAS was identified as the presumptive causative organism with the use of the standard rapid streptococcal diagnostic kit. We believe the rapid test kits may be a useful adjunct in the diagnosis and treatment of this catastrophic illness and may play a role in limiting the spread of infection.