Search PubMed⌕ Search

Biomedical subjects

J J Cottrell

Publications and source records attributed to J J Cottrell.

17 recordsLinked to original sources
PubMed2005

Glucagon-like peptide-2 protects against TPN-induced intestinal hexose malabsorption in enterally refed piglets.

Premature infants receiving chronic total parenteral nutrition (TPN) due to feeding intolerance develop intestinal atrophy and reduced nutrient absorption. Although providing the intestinal trophic hormone glucagon-like peptide-2 (GLP-2) during chronic TPN improves intestinal growth and morphology, it is uncertain whether GLP-2 enhances absorptive function. We placed catheters in the carotid artery, jugular and portal veins, duodenum, and a portal vein flow probe in piglets before providing either enteral formula (ENT), TPN or a coinfusion of TPN plus GLP-2 for 6 days. On postoperative day 7, all piglets were fed enterally and digestive functions were evaluated in vivo using dual infusion of enteral ((13)C) and intravenous ((2)H) glucose, in vitro by measuring mucosal lactase activity and rates of apical glucose transport, and by assessing the abundances of sodium glucose transporter-1 (SGLT-1) and glucose transporter-2 (GLUT2). Both ENT and GLP-2 pigs had larger intestine weights, longer villi, and higher lactose digestive capacity and in vivo net glucose and galactose absorption compared with TPN alone. These endpoints were similar in ENT and GLP-2 pigs except for a lower intestinal weight and net glucose absorption in GLP-2 compared with ENT pigs. The enhanced hexose absorption in GLP-2 compared with TPN pigs corresponded with higher lactose digestive and apical glucose transport capacities, increased abundance of SGLT-1, but not GLUT-2, and lower intestinal metabolism of [(13)C]glucose to [(13)C]lactate. Our findings indicate that GLP-2 treatment during chronic TPN maintains intestinal structure and lactose digestive and hexose absorptive capacities, reduces intestinal hexose metabolism, and may facilitate the transition to enteral feeding in TPN-fed infants.

Algorithms↗
PubMed2004

Inhibition of endogenous nitric oxide production influences ovine hindlimb metabolism independently of insulin concentrations.

The hindlimb arteriovenous difference (AVD) model was used to determine whether 30 mg/ kg of the nitric oxide synthase (NOS) inhibitor L-NGnitroarginine methyl ester (hydrochloride; L-NAME) inhibited ovine NO synthesis and influenced muscle metabolism. Eight Border Leicester x Merino cross lambs (50 to 55 kg BW) were infused with saline (control) or saline containing L-NAME via an indwelling jugular vein catheter in a balanced randomized crossover design with 3 d between treatments. The abdominal aorta and deep femoral vein were catheterized for assessment of AVD of hind limb metabolism. Arterial hematocrit and insulin concentration and both arterial and venous concentrations of nitrate/nitrite (NOx), glucose, lactate, NEFA, and urea were determined. Infusion of L-NAME decreased arterial NOx concentrations (P = 0.049), indicating inhibition of systemic NO synthesis. Treatment had no effect on arterial (3.5 vs. 3.6 +/- 0.19 mmol/L for control and L-NAME lambs, respectively; P = 0.39) or venous (3.3 vs. 3.4 +/- 0.16 mmol/L, P = 0.55) plasma glucose concentrations or on glucose AVD (0.19 vs. 0.27 +/- 0.065 mmol/L, P = 0.20). There was an interaction (P = 0.038) between time and treatment, such that L-NAME initially increased the AVD of glucose (up to 180 m) divergent from control lambs. The response was then decreased before a possible inflection beyond 240 min. Infusion of L-NAME increased hindlimb venous NEFA (222 vs. 272 +/- 13.2 micromol/L, P = 0.007) and NEFA AVD (79.4 vs. -13.3 +/- 31.5 micromol/L, P = 0.018). These metabolic changes were independent of plasma insulin concentrations, which were not affected by L-NAME infusion (25.3 vs. 27.8 +/- 3.62 mU/L, P = 0.85). The increase in hindlimb lipolysis after L-NAME infusion does not seem to be due to increased lipolysis of plasma triacylglycerol because circulating arterial (155 vs. 142 +/- 20.8 micromol/L, P = 0.58), venous (154 vs. 140 +/- 20.5 micromol/L, P = 0.50), and AVD (1.0 vs. 2.9 +/- 3.17 micromol/L, P = 0.38) triacylglycerol concentrations were unaffected by L-NAME infusion. In conclusion, these data indicate that infusion of 30 mg of L-NAME/kg inhibits NO synthesis, which in turn influences fat and carbohydrate metabolism in the ovine hindlimb independently of plasma insulin concentrations.

Animals↗
PubMed1999

Effects of prognosis, perceived benefit, and decision style on decision making and critical care on decision making in critical care.

OBJECTIVE: To assess the effects of prognostic estimates, perceived benefit of treatment, and practice style on decision-making in critical care. DESIGN: Randomized assignment of subjects to either of two versions of a questionnaire designed to elicit treatment decisions for six intensive care unit cases based on actual patients. One version offered optimistic survival forecasts; the other, pessimistic forecasts. SUBJECTS: A random sample of 120 clinicians obtained from the Canadian Critical Care Society was contacted by mail. One version of the questionnaire was randomly assigned and mailed to each. Thirty-four replies, 17 for each version (response rate, 28%), were received and analyzed. MEASUREMENTS AND MAIN RESULTS: A list of treatment/management options was developed for each case, in three categories: recommended, questionable, and unacceptable. Subjects were also able to list new options that they would order that were not on the list. The dependent variables were the number of actions ordered in each category and the total for each case. Perceived benefit was measured by comparing subjective estimates of the probability of survival with the optimistic/pessimistic forecast given in the case. Practice style was assessed by correlating the total number of actions ordered across all possible pairs of cases. There were no significant differences between the two questionnaires on actions ordered either by category or by amount per category. Perceived benefit did not appear to be an important factor in decision-making. However, statistically significant correlations provide evidence for practice style in intensive care unit decision-making on an interventionist/noninterventionist dimension. CONCLUSIONS: There is no evidence that erroneous or biased prognostic estimates affect intensive care unit treatment choices. Neither the principle of maximizing expected utility nor the Rule of Rescue appear to affect these decisions systematically, but practice style does.

Canada↗
PubMed1995

Home oxygen therapy. A comparison of 2- vs 6-month patient reevaluation.

STUDY OBJECTIVE: To contrast the effectiveness of 2- vs 6-month reevaluation intervals on both clinical outcome and cost in patients requiring continuous home oxygen therapy (HOT). DESIGN: Prospective, randomized clinical trial. SETTING: The outpatient program of a university-affiliated Veterans Affairs Medical Center (VAMC) Pulmonary Service. PATIENTS: Fifty patients were chosen from among a cohort of 200 patients currently enrolled in our HOT program. All met specific arterial blood gas criteria, were able to give informed consent, had at least 6 months of prior HOT usage, and did not have any illness expected to independently shorten life expectancy. INTERVENTIONS: Baseline resting oxygen flow rates were prescribed based on the results of arterial blood gas measurements so as to attain a PaO2 > 60 mm Hg. Flow rates were adjusted as needed during a 12-min walk to maintain pulse oximetry readings > 90%. No adjustments in baseline flow rates were made during sleep. Identical evaluations were repeated at either 2- or 6-month intervals. MEASUREMENTS AND RESULTS: At 1-year follow-up, there were no significant differences between the 2- and 6-month groups in any of the clinical outcome parameters measured, ie, number of emergency department visits, number of hospitalizations, number of days hospitalized, or mortality. Total costs were not significantly different between the two groups. Evaluation costs were less in the 6-month follow-up group. CONCLUSIONS: After attaining stability following at least 6 months of continuous HOT usage, patients receiving continuous HOT need not be routinely reevaluated more frequently than every 6 months.

Aged↗
PubMed1995

Inflight arterial saturation: continuous monitoring by pulse oximetry.

The ability of newer airliners to fly at higher altitudes has resulted in an increased altitude exposure to both airline crews and passengers. This increase in altitude exposure has the potential to place some individuals at risk for desaturation. Using pulse oximetry, the arterial oxygen saturation of 42 airline crew members was continuously monitored on 22 regularly scheduled commercial flights. Mean nadir arterial oxygen saturations fell from 97.0% preflight to 88.6% at cruising altitudes. Pulse oximetry results revealed large variations between individuals. Individual nadir saturations ranged from 93% to 80%. Modern aircraft flight may result in desaturations even among healthy aircrew. The effects on human performance remain unknown.

Adult↗
PubMed1993

Forecasting survival in the medical intensive care unit: a comparison of clinical prognoses with formal estimates.

Physicians often need to make prognostic judgments. In the present study, the accuracy was explored of survival estimates for patients in the Medical Intensive Care Unit (MICU). Estimates were made by physicians and nurses several times during each patient's stay in the MICU and were compared to those of the APACHE II scale, a widely used quantitative index for critically ill patients. ROC curve and calibration curve analyses were performed to assess the accuracy of these estimates. Results revealed that MICU personnel were fairly accurate discriminators of patients who survived vs. who died, although there was a consistent tendency to underestimate survival. In addition, there was some relationship between the level of physician training and forecasting accuracy, but only within the patient's first 24 hours in the MICU. Finally, the estimates of physicians did not differ significantly from those of the APACHE II scale. Physicians tended to be better calibrated in their predictions, while the APACHE II scale was slightly superior in terms of discrimination.

Forecasting↗
PubMed1992

Is loss of body weight in chronic obstructive pulmonary disease patients with emphysema secondary to low tissue oxygenation?

The available clinical information to date does not support the hypothesis that tissue oxygen debt is the primary cause of the wasting process in the chronic obstructive pulmonary disease (COPD) patient population. However, this should not deter the 'believers' of the hypothesis from further investigation. The information outlined above supports the need for reconsideration of this clinical problem. Tissue oxygen requirements and utilization is a complex interplay of multiple variables. Likewise, the assessment of nutritional status in the setting of oxygen therapy is complicated by shifts in body fluid compartments independent of changes in the fat-free mass (FFM). Utilization of newer techniques will be required to resolve the contribution of low tissue oxygenation to the wasting process. The continued development of noninvasive methods for the assessment of tissue metabolism, cardiac function, and tissue energy requirements will allow investigators to further clarify the relationship between tissue oxygenation and metabolism in patients with COPD. Clinical trials designed to examine this issue must recognize the multiple effects of oxygen on all aspects of nutrient utilization, including caloric intake, needs, and tissue delivery. Failure to address all aspects of this system will lead to continued debate regarding the etiology of weight loss in the COPD patient population.

Clinical Trials as Topic↗
PubMed1992

Preoperative assessment of the thoracic surgical patient.

The preoperative assessment before pulmonary resection is both important and difficult. Pulmonary function testing is imperative to assess pulmonary reserve. If the FEV1 is less than 2 L, differential perfusion lung scans are used for a more accurate assessment. Exercise testing may also be used as an adjunct for high-risk patients or procedures. Although a predicted postoperative FEV1 of 800 mL is a widely accepted minimum for resection, it has not been scientifically validated. Lesser procedures (segmentectomy and wedge resection) may be performed with acceptable mortality in patients who were previously not considered surgical candidates.

Exercise Test↗
PubMed1989

Emergency transport by aeromedical blimp.

Recently there has been an explosive growth in the use of helicopters and fixed wing aircraft for the transportation of patients who are ill and injured. Although using such methods of transport may result in faster access to health care centres, their ultimate role for the civilian population is unclear. Unfortunately, there are many problems associated with aeromedical transport, particularly with rotary wing aircraft, which have shown an alarming tendency to crash. The use of lighter than air vehicles (blimps, hot air balloons) might offer most of the advantages of conventional aieromedical transport, with an appreciable improvement in safety.

Aircraft↗
PubMed1988

Altitude exposures during aircraft flight. Flying higher.

Commercial aircraft flight represents a highly variable altitude exposure that may result in significant hypoxemia for patients with cardiac or pulmonary disease. To develop better guidelines for travel by patients with cardiopulmonary disease, we measured inflight cabin altitude on 204 regularly scheduled commercial aircraft flights. Measurements were carried out on 16 different types of aircraft, operated by 28 airlines. The median altitude exposure for all flights was 6,214 feet (1894 m). Cabin altitudes ranged from sea level to 8,915 feet (2717 m). Inspired partial pressure of oxygen falls from 159 mm Hg at sea level to 127 mm Hg at 6,200 feet and further declines to 113 mm Hg at 9,000 ft. There was no significant difference between domestic and international flights. New generation aircraft fly at higher altitudes than older aircraft and are associated with greater altitude exposures to passengers (p = 0.002). The risk of hypoxemia may increase as newer model aircraft replace older ones.

Air Pressure↗
PubMed1983

A simplified computer report. Towards an understandable pulmonary function test.

We have developed a graphic format for the display of pulmonary function test results. Patient test results appear as a series of horizontal bar graphs. Each bar length is proportional to the test result and is printed over the normal ranges. This format allows rapid recognition of individually abnormal values. We have also grouped bars to create distinctive patterns characteristic of obstructive or restrictive lung disease. A computer program generates a custom form for each patient, displaying the results and ranges only for the specific test performed on that individual. No preprinting of forms is required. Written in the BASIC computer language, this program was designed to be flexible. A change of program parameters requires only minor program modification. In addition, because of its simplicity, our program can be implemented on almost any computer printer.

Computers↗
PubMed1983

Pulmonary function in progressive systemic sclerosis. Comparison of CREST syndrome variant with diffuse scleroderma.

The pulmonary function and chest roentgenograms were evaluated in 88 patients with the CREST syndrome variant of progressive systemic sclerosis (PSS or scleroderma). Seventy-two percent of the patients had abnormal pulmonary function. An isolated decrease in diffusing capacity was the most common abnormality noted, followed by restrictive abnormalities and airway obstruction. Chest roentgenograms revealed interstitial infiltrates consistent with pulmonary fibrosis in 33 percent. When compared to a contemporaneous group of 77 patients with PSS and diffuse scleroderma, patients with the CREST syndrome had similar abnormalities on pulmonary function testing and chest roentgenogram. However, patients with the CREST syndrome had a lower mean diffusing capacity despite a higher mean vital capacity; this combination of findings suggests primary pulmonary vascular disease. Calcified granulomata were identified significantly more often in PSS-CREST patients, while superior rib notching occurred exclusively in patients with PSS and diffuse scleroderma. The CREST variant of PSS is associated with frequent roentgenographic and pulmonary function abnormalities similar to those seen in PSS with diffuse scleroderma.

Adult↗
PubMed1983

Pulmonary function testing. What is 'normal'?

For many years, confusion has existed concerning the normal range for pulmonary function test results. Using statistical guidelines that have been traditionally applied to the interpretation of measured forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), we have redefined normal limits for the most common pulmonary function test values, including those for FVC, FEV1, mean forced expiratory flow during the middle half of the FVC, FEV1 as a proportion of FVC, residual volume, functional residual capacity, total lung capacity, diffusion capacity, maximum voluntary ventilation, and peak expiratory flow. Our goal is to provide a simple and consistent scheme for interpretation of pulmonary function test data. We consider the assumptions used to achieve this simplification to be reasonable, as long as their limitations are understood.

Humans↗
PubMed1982

Office spirometry.

Explore the source record for details and available documents.

Ambulatory Care↗
PubMedDate not supplied

In-flight medical emergencies. One year of experience with the enhanced medical kit.

Recent regulations require commercial US aircraft to carry an enhanced medical kit. We reviewed kit use on United Airlines during the initial year of the regulations. We also surveyed passengers who became ill during flight and health care providers who used the new kit. The medical kit was used 362 times on 361 flights (once in every 1900 flights or one use for every 150,000 air travelers). Health care providers indicated that the kit was useful in more than 80% of emergencies and was occasionally lifesaving. In the emergencies in which the kit was used, 70% fell into one of seven major diagnostic groupings, including syncope/near syncope (29%), cardiac/chest pain (16%), asthma/lung disease/shortness of breath (10%), and allergic reactions (5%). With 450 million domestic air travelers per year, we would expect 3000 in-flight medical emergencies annually, and conclude that the enhanced medical kit is beneficial and propose that its effectiveness would be improved by the addition of a bronchodilator for inhalation.

Adult↗