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Biomedical subjects

B Coleman

Publications and source records attributed to B Coleman.

At least 37 records · Page 2Linked to original sources
PubMed1989

Determinants of urea nitrogen production in sepsis. Muscle catabolism, total parenteral nutrition, and hepatic clearance of amino acids.

The major determinants of urea production were investigated in 26 patients with multiple trauma (300 studies). The body clearances (CLRs) of ten amino acids (AAs) were estimated as a ratio of muscle-released AAs plus total parenteral nutrition-infused AAs to their extracellular pool. While clinically septic trauma (ST) patients without multiple-organ failure syndrome (MOFS) had a higher level of urea nitrogen production (25.6 +/- 13.4 g of N per day) compared with nonseptic trauma (NST) patients (14 +/- 7.5 g of N per day) and with ST patients with MOFS (4.28 +/- 1.5 g of N per day), in all groups urea N production was found to be a function of muscle protein degradation (catabolism), total parenteral nutrition-administered AAs, and the ratio between leucine CLR and tyrosine CLR (L/T) (r2 = .82, P less than .0001). Since tyrosine is cleared almost exclusively by the liver, the L/T ratio may be regarded as an index of hepatic function. The significant differences between urea N production in ST and NST patients lay in an increased positive dependence on muscle catabolism and increased negative correlation with L/T in the ST group. At any L/T ratio, urea N production was increased in ST patients over NST patients, but in ST patients with MOFS, it fell to or below levels of NST patients. These data show that the ST process is associated with enhancement of ureagenesis, due to increased hepatic CLR of both exogenous and endogenous AAs. In sepsis with MOFS, a marked inhibition of urea synthesis occurs, partially explained by a decreased hepatic CLR of non-branched-chain AAs.

Adult↗
PubMed1989

Nursing implication for pulmonary artery balloon counterpulsation: a treatment for right ventricular dysfunction after cardiac surgery.

PPRVD is a phenomenon frequently observed in the operating room. Its development can be attributed to a single or many factors associated with cardiac operation. Namely, its presence is precipated by injury to the RV myocardium or changes in the normal hemodynamic functions of the RV. While PPRVD occurs in isolation, it is usually seen with concomitant LV dysfunction. When conventional medical management of LV dysfunction does not improve yet unmasks RV dysfunction, some type of ventricular assist device to support RV dysfunction may be needed to wean patients from cardiopulmonary bypass such as PABC. PABC has been demonstrated to be useful in the management of mild to moderate PPRVD and weaning from CPB. Severe PPRVD has not been demonstrated to benefit from PABC. The major concern in managing PPRVD is the lack of quantifiable criteria for determining levels of RV injury. Research is continuing in this area. Likewise, investigations are under way to develop a transvenous PABC catheter. This catheter would allow for increased PABC use as it would not require surgical placement or removal. The present PABC model could potentially be used in any hospital that uses conventional intra-aortic balloon counterpulsation. The patient presented in this case was cared for in a 350-bed community hospital in the Northeast section of the United States. A PABC patient can present a unique nursing challenge. It is hoped that this article will assist nurses in the future management of these patients.

Aged↗
PubMed1988

Inhibition of post-traumatic septic proteolysis and ureagenesis and stimulation of hepatic acute-phase protein production by branched-chain amino acid TPN.

Previous studies have shown that severe sepsis after major trauma results in the reprioritization of release of hepatic acute-phase proteins (APP). They suggest competition for leucine for nutritional utilization may be responsible. To test this hypothesis, a branched-chain enriched (46.6%) amino acid mixture (BCAA) was administered on a prospective randomized basis with standard TPN therapy to 16 septic post-trauma patients. After sepsis was diagnosed, a randomized therapy (control-TPN or BCAA-TPN) was given for 12 days, or until death occurred. Total calories and amino acid nitrogen (N) administered were not different in the two groups (t-test) and q 8 h (347 study periods) amino acid clearances, urinary urea nitrogen excretion, muscle proteolysis from 3-methyl-histidine (3-MH) excretion, and standard indices of sepsis severity and hepatic function were measured, as well as platelets (PLAT), leucocytes (WBC), albumin (ALB), and six acute-phase proteins: C-reactive protein (CRP), alpha-1-antitrypsin (A1TRIP), fibrinogen (FIBRIN), alpha-2-macroglobulin (AMACRO), ceruloplasmin (CERUL), and transferrin (TRANS). Using Scheffé analysis of all contrasts the data showed: BCAA resulted in a fall in 24-hour urea N excretion (24.0 to 20.0 gm/24 hr) and in proteolysis (138 to 126 gm/24 hr) (p less than 0.0001). Prestudy CRP levels were all elevated, but compared to control where APP reprioritization occurred, over the initial 10 days of therapy BCAA patients had a more rapid fall in CRP with a more rapid rise in FIBRIN, TRANS, CERUL, ALBUMIN, AMACRO, and A1TRIP (all p less than 0.0001) relative to CRP. Also, the sepsis-reduced clearances of glutamine and glutamate, alanine, and proline were increased (p less than 0.0001) during BCAA even though urea nitrogen production was reduced (p less than 0.0001). The increase in leucine clearance with BCAA-enriched TPN was positively correlated (r2 = 0.601; p less than 0.0001) with the increase in the sum of all APP and ALB and was also associated with an increase both in FIBRIN and in platelets (p less than 0.0001). The BCAA-related increase in FIBRIN (9.1 to 11.9 mg/ml) occurred at the same time as a fall in prothrombin time (p less than 0.0001). BCAA-enriched TPN reduced proteolysis and amino acid catabolism and appeared to increase the levels of the more rapidly appearing anti-inflammatory and nutritional hepatic APP and formed coagulation elements in post-traumatic sepsis.

Acute-Phase Proteins↗
PubMed1987

Effects of retinoic acid on the growth and morphology of hamster tracheal epithelial cells in primary culture.

Hamster tracheal epithelial cells were grown in primary culture on a collagen gel substrate in hormone-supplemented serum-free Ham's F12 medium with 10(-8) M retinoic acid (RA+), or without retinoic acid (RA-). On days 1 and 2, the colonies were composed of large (secretory) cells and lesser numbers of small (basal) cells; ciliated cells were rare. At these times, cell number, thymidine incorporation, and total labelling indices (small and large cells, combined) were similar in RA+ and RA- cultures, but the large cells became flat in RA- medium on day 2. On days 3-5, thymidine incorporation and total labelling indices were less in RA- than RA+ cultures, and on days 4-6, cell numbers were decreased in RA- cultures. On day 3, the large cells of the RA- colonies had flattened further and clusters of small basal cells had formed. On day 4, the RA+ colonies were composed of densely-packed cuboidal secretory cells, small basal cells were inconspicuous; the total labelling index was about 27%. The RA- colonies were composed of large flat secretory cells and numerous small basal cells which were clustered in groups; the total labelling index was about 7%. Since large and small cells could be discriminated by size in RA- colonies, a labelling index was generated based on cell size. On days 2, 3 and 4, the labelling index of the small basal cells in the RA- colonies was 44%, 43% and 24% respectively, whereas the labelling index of the large secretory cells fell rapidly over the same period (56%, 14% and 2%). On days 5 and 6, the cuboidal secretory cells in the RA+ cultures had differentiated further and the cells were stratified focally. Some new ciliated cells had formed on day 6. In RA- cultures, mucous granules were not observed in the large flat cells and ciliated cells were not seen. The total labelling indices were 11% and 0.35% in RA+ cultures, and 0.5% and 0.25% in RA- cultures on days 5 and 6, respectively. The study shows that the target cell for vitamin A in the hamster tracheal epithelium is the secretory (mucous) cell. When retinoic acid was deficient, the secretory cells flattened and their capacity to divide was greatly diminished. Since the basal cells continued to replicate when the secretory cells did not, the population density of the basal cells increased disproportionally, which could be interpreted erroneously as a "basal cell hyperplasia".(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Estimation of left ventricular mass in conscious dogs.

The short-axis area-length method for the estimation of left ventricular mass (LVM) and volume was validated in 24 formaldehyde-fixed canine hearts, using the truncated ellipsoid model. Estimates of the short-axis muscle area were highly correlated with directly measured values (R = 0.92; P less than 0.001). Similarly, LVM calculated using the area-length method showed good correlation with the actual weight of the left ventricle (LVW) (R = 0.85; P less than 0.001). When the regression equation was used, retrospectively, to correct the LVM estimates, the correlation between the actual LVW and the calculated LVM was markedly improved (R = 0.96; P less than 0.001). In awake dogs instrumented for measuring transverse and long axis ventricular dimensions using sonomicrometry, short-axis two-dimensional echocardiograms were used to convert the sonar external transverse dimensions to true diameters. The combined use of the corrected diameters and the regression equation to calculate LVM in the intact dog resulted in values that were highly correlated with the actual LVW (R = 0.95; P less than 0.001). Application of this technique for monitoring LVM in awake instrumented dogs demonstrated the method to be reproducible from day to day and to be sensitive enough to detect serial changes in mass such as during the development of left ventricular hypertrophy.

Animals↗
PubMed1986

Sonographic assessment of the endometrium in patients undergoing in vitro fertilization.

Sonography has an important role in the care of infertile patients undergoing in vitro fertilization. Unlike the ovarian follicle, sonographic changes in the endometrium during induction have not been extensively investigated. To determine whether changes in endometrial thickness or changes in endometrial texture would predict subsequent pregnancy, a randomized, double-blind review of 320 studies was performed. None of the endometrial patterns nor any particular change from one pattern to another during induction was predictive of subsequent pregnancy. Although differences in endometrial thickness between non-pregnant and subsequently pregnant patients were noted, on an individual basis, endometrial thickness was not a useful predictor.

Double-Blind Method↗
PubMed1986

Computers in the care of the critically ill patient.

The use of computer-based care-oriented physiologic evaluation is still in its developmental stage. However, it seems likely that the capability of computer-based applications to critically ill patients are such that quality and cost-effective intensive care can be delivered in a timely and expeditious fashion. This application has a high promise of helping to reduce the mortality and morbidity of the critically ill or injured surgical patient, now and in the future.

Adult↗
PubMed1985

Reprioritization of hepatic plasma protein release in trauma and sepsis.

We studied the temporal pattern of seven hepatic synthesized plasma proteins in 26 severely injured patients beginning in the immediate posttrauma period. Clinical sepsis developed in ten patients between three and eight days after injury, and 16 patients had nonseptic courses. In the initial five days after injury, except for albumin, all acute-phase protein levels rose. However, if sepsis developed, C-reactive protein, fibrinogen, ceruloplasmin, and alpha 1-antitrypsin levels continued to be elevated after the initial five posttrauma days, while transferrin, albumin, and alpha 2-macroglobulin levels fell. This differential response became more extreme as sepsis progressed. Covariance analysis of the regression of the five true acute-phase hepatic proteins on C-reactive protein showed that, when sepsis occurred after major traumatic injury, the C-reactive protein rise was associated with a significant reprioritization of hepatic acute-phase plasma protein release. This reprioritization response seems to be both a predictor of sepsis as well as a measure of the adequacy of the host response to trauma and sepsis.

Acute-Phase Proteins↗
PubMed1985

Development of hamster tracheal epithelium: I. A quantitative morphologic study in the fetus.

The development of the tracheal epithelium was studied in hamsters, beginning on fetal day 10 and ending on fetal day 16, shortly after birth. The epithelial morphology was characterized and as soon as the cells could be recognized by type (day 14) their proportions were quantified along dorsal and ventral surfaces from larynx to carina. At all times, columnar cells of the dorsal surface were taller than those of the ventral surface. On days 10 and 11 the simple epithelium was composed of poorly differentiated columnar cells, but on day 12 organoid clusters, consistent with the morphology of neuroepithelial bodies, were observed; four clusters were seen along the dorsal epithelium in one section. The epithelium was pseudostratified on day 13, composed of short and columnar cells. Most columnar cells were poorly differentiated but a few preciliated and ciliated cells were recognizable dorsally, especially at the tracheal poles. Hemidesmosomes were seen at the base of some short cells on day 14, and rough endoplasmic reticulum was moderately developed in some columnar cells, suggesting that these cells were prebasal and presecretory cells, respectively. Preciliated and ciliated cells, which were most prevalent caudally, accounted for about 14% of all dorsal epithelial cells on day 14, but they were rare in the ventral surface, about 0.1%. The epithelial cells were sufficiently specialized by days 15 and 16 to allow quantification by type. Proportions of basal, presecretory, and preciliated-ciliated cells were similar on both days but the cellular makeup of dorsal and ventral surfaces was significantly different. There were more basal cells ventrally (36-40%) than dorsally (22-23%), and more preciliated-ciliated cells dorsally (18-21%) than ventrally (about 1%). On days 15 and 16 differences also existed along both surfaces between cranial and caudal parts of the trachea. Basal cells were more prevalent cranially and preciliated-ciliated cells were more prevalent caudally.

Animals↗
PubMed1985

Development of hamster tracheal epithelium: II. Cell proliferation in the fetus.

Proliferation of epithelial cells in the fetal trachea was studied in hamsters, beginning on the 10th gestational day and ending on the 16th day, shortly after birth. The mean mitotic index (MI) was highest on day 10, with no statistical confirmation of a change between days 10 and 11. The MI fell to about 2% on days 12 and 13, and declined thereafter to about 0.3% on day 16. The MIs for dorsal and ventral surfaces were compared and values were similar except on day 10, when ventral exceeded dorsal, and on day 12, when dorsal exceeded ventral, 2.56% and 1.3%, respectively. On days 10, 11, and 12 the epithelium was simple, composed of poorly differentiated columnar cells that proliferated. On day 13 the epithelium was pseudostratified owing to the presence of a few short cells that did not reach to the lumen. Throughout the fetal period, proliferation of columnar cells predominated but division of short (basal) cells increased from 8% to 40% of the total mitotic activity between day 13 and day 15. Proliferation of basal cells then declined, so that on day 16, 84% of all cells in mitosis were columnar. If basal cells divide to make more of themselves they must proliferate rapidly between day 13 and day 15, because they were virtually absent on day 12 but accounted for about 36% of the ventral and 23% of the dorsal epithelial cells on day 16. Based on the results, a hypothetical model is proposed for the formation of pseudostratified mucociliary epithelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Development of hamster tracheal epithelium: III. Illustration of statistical methods for proportional data in biology.

The data in the two companion papers (McDowell et al., 1985a,b) are of a commonly occurring type in which the dependent variable takes on one of a small number of distinct values; we wish to compare the relative proportions in which these values occur. Student's test is inapplicable. We explain here in detail the linear logistic model that is appropriate, using our data as an example. Several reasonable models must first be fit. We did this by the maximum likelihood method, using a computer. We then used a chi 2 test to decide statistically between models. This process amounts to deciding directly which of the independent variables are important in determining the outcome, and thus it is the center of physiologic interest. The outcome depends on the initial choice of parametrization of the model. Generalizations are required in more complicated, but still commonly occurring, types of data.

Animals↗
PubMed1985

Serum-mediated depression of neutrophil chemiluminescence following blunt trauma.

To investigate one possible mechanism responsible for decreased neutrophil bactericidal activity following trauma, the chemiluminescence response of normal neutrophils was measured following incubation in nonseptic and septic serum from 19 blunt trauma patients. Incubation of normal neutrophils in septic patients' sera (61 studies) resulted in a marked decrease in the chemiluminescence response (36 +/- 26% of control), compared to incubation in nonseptic sera (92 studies, 80 +/- 53% of control; p less than 0.005). This difference between nonseptic and septic serum was apparent immediately after injury, prior to the development of sepsis (47 +/- 4% versus 77 +/- 12%; p less than 0.05). The depression of the CL response was due to a suppressive factor present in septic patients' sera. This factor was nondialyzable and was present in high performance liquid chromatography (HPLC) fractions containing protein of molecular weight 50 to 100,000. Removal of albumin using Affigel-blue did not remove the suppressive factor. In contrast to the suppressive effect of septic trauma serum, septic patients' neutrophils had a normal chemiluminescence response after their isolation and washing. We conclude that trauma results in the generation of a serum factor that suppresses neutrophil chemiluminescence and that is present in greater amounts in patients who eventually become septic. This factor may be responsible for the decreased bactericidal activity and depressed host defense following injury.

Adult↗
PubMed1985

CT in pelvic trauma.

The use of computed tomography is extremely important in the care of patients with pelvic trauma. We believe that it should be performed on all patients with severe pelvic injury. It depicts the pelvic anatomy in exquisite detail, enabling one to plan therapy on the basis of pathologic anatomy rather than the presumed mechanism of injury. CT is more expensive than tomography but gives considerably more information at a lower radiation dose. It is also of considerable value in postoperative follow-up for determination of the adequacy of reduction and fracture healing.

Acetabulum↗
PubMed1985

Increased dependence of leucine in posttraumatic sepsis: leucine/tyrosine clearance ratio as an indicator of hepatic impairment in septic multiple organ failure syndrome.

The body clearance of 10 plasma amino acids (AA) was determined from the rate of compared muscle-released AA and AA administered by infusion of total parenteral nutrition (TPN) compared to their estimated extracellular (ECW) pool in patients with multiple trauma with (n = 10) or without (n = 16) sepsis at 8-hour intervals. In both nonseptic and septic trauma, increasing TPN increased the mean clearance rate of all infused AA. When the individual AA clearance rates were normalized by the total AA infusion rate, regression-covariance analysis revealed that patients with sepsis had relatively impaired clearances of alanine (p less than 0.01) and methionine, proline, phenylalanine, and tyrosine p less than 0.05 for all). In contrast, the clearances of branched-chain AA (BCAA) valine and isoleucine were maintained, and the clearance of leucine was higher (p less than 0.05) in trauma patients with sepsis than in those without. At any AA infusion rate, compared with surviving patients with sepsis (p less than 0.05), patients who developed fatal multiple organ failure syndrome (MOFS) showed increased clearances of all BCAA with further impaired clearance of tyrosine. The clearance ratio of leucine/tyrosine was increased in MOFS at any AA infusion rate (p less than 0.0001), was an indicator of severity, and, if persistent, was a manifestation of a fatal outcome. Because tyrosine metabolism occurs almost entirely in the liver while leucine can be utilized by viscera and muscle, these data suggest early and progressive septic impairment of the pattern of hepatic uptake and oxidation of AA with a greater body dependence on BCAA, especially leucine, as septic MOFS develops.

Adolescent↗
PubMed1985

The physiologic meaning of the respiratory index in various types of critical illness.

Seven hundred and sixty cardiorespiratory studies, from 151 critically ill or high-risk general surgical patients with extrapulmonary (S) or pulmonary (P) sepsis, cirrhotic liver disease (L), or cardiac failure (C), were analyzed to assess the determinants of a simple, easily obtained measure of respiratory oxygen exchange, the respiratory index (RI). The pattern of cardiorespiratory abnormalities was studied and correlated with the change in RI. The most important relations were with shunt (QS/QT), mixed venous O2 (PvO2), VD, and VE. Higher F1O2 and positive end-expiratory pressure (PEEP) were needed as the RI rose, indicating a greater severity of illness. Regression analysis of all types of critically ill patients and surgical controls showed that QS/QT, PvO2, and F1O2 interacted together to explain most of the variability of the RI. The regressions in each homogeneous patient disease category were all highly significant (p less than .0001) but had somewhat similar coefficients and explained the variability in RI to different degrees. The data suggest that patients with extrapulmonary sepsis or cirrhotic liver disease have an increase in RI (over that in controls) primarily due to a large increase in CI at the high QS/QT caused by the ventilation/perfusion (VA/QT) maldistribution characteristic of these diseases. However, patients with P or C have a disproportionate rise in RI at any given QS/QT compared to that in high-flow states alone, suggesting in P a direct alveolar limitation of oxygen exchange over and above any level of VA/QT mismatching, and suggesting in C a disproportionate decrease in PvO2 that magnifies the QS/QT effect even though VA/QT is more uniform.

Biometry↗