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Biomedical subjects

R V Maier

Publications and source records attributed to R V Maier.

At least 127 records · Page 7Linked to original sources
PubMed1988

Superoxide production by neutrophils in a model of adult respiratory distress syndrome.

Neutrophils (polymorphonuclear leukocytes [PMNs]) are thought to contribute to the pathophysiology of adult respiratory distress syndrome (ARDS) by the release of toxic oxygen metabolites. This study investigated superoxide production by circulating and bronchoalveolar lavage (BAL) PMNs in a rat model of ARDS induced by chronic Escherichia coli (lipopolysaccharide) endotoxemia. Superoxide production was stimulated by fmet-leu-phe, opsonized zymosan, and phorbol myristate acetate. Circulating and BAL PMNs from lipopolysaccharide-infused rats compared with PMNs from control rats are primed for nonselective increased superoxide production. The BAL PMNs are not only partially primed to release superoxide on adherence, they concomitantly have a depressed superoxide response to a phagocytic (opsonized zymosan) stimulus. These PMN responses may partially explain both the pulmonary injury and the increased susceptibility to pulmonary infection seen in patients with ARDS.

Animals↗
PubMed1988

A glycolipid precursor of bacterial lipopolysaccharide (lipid X) lacks activity against endothelial cells in vitro and is not toxic in vivo.

Lipid X (2,3-diacylglucosamine-1-phosphate) accumulates in mutants of Escherichia coli incapable of assembling the disaccharide backbone of lipid A, the principle endotoxic moiety of bacterial lipopolysaccharide (LPS). We compared the effects of lipid X on cultured bovine aortic endothelial cell (BEC) viability and prostacyclin (PGI2) release with those of lipid A and LPS. At 10(-5) M, both LPS and lipid A produced significant BEC cytotoxicity (percentage cytotoxicity 69 +/- 4 for LPS and 51 +/- 11 for lipid A) and induced a variable but consistent increase in the release of PGI2 (11- to 73-fold increase for LPS and 4- to 6-fold increase for lipid A). Lipid X, in contrast, was not toxic and did not induce PGI2 release at 10(-4) M. Pretreatment and coincubation of BEC with lipid X, at a concentration 100 times greater than LPS, failed to prevent LPS-mediated cytotoxicity. Intravenous infusion of lipid X in goats had no effect except for a modest elevation in the pulmonary artery pressure during the period of infusion. Moreover, pretreatment of goats with lipid X (70 micrograms/kg) did not block the effects of a subsequent infusion of LPS (5 micrograms/kg). These data suggest that a fatty acid-substituted disaccharide is the minimal molecular requirement for the numerous effects in vivo and activity in vitro induced by LPS. Furthermore, these effects are not prevented by pretreatment with a monosaccharide precursor of lipopolysaccharide, lipid X, at a dose 10- to 100-fold greater than that of LPS.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Neutrophil phagocytosis during endotoxin-induced lung injury.

UNLABELLED: Depressed neutrophil (PMN) phagocytosis in patients with ARDS may contribute to the known increased incidence of pulmonary sepsis. To evaluate changes in phagocytosis, circulating PMNs from normal rats were compared to circulating and alveolar PMNs (obtained by bronchoalveolar lavage, BAL) from rats after 72 hr of endotoxin infusion (LPS-Rx)-induced acute lung injury. Since phagocytosis correlates with adherence, PMN adherence to coverslips and to a standard nylon wool column was also measured. PMN adherence to nylon wool was 65% for control, 77% for circulating LPS-Rx, and 20% for BAL PMNs. As a measure of phagocytosis the PMNs were incubated for 30 min with opsonized fluorescent (FITC) tagged yeast. Total PMN with yeast were 95.4 +/- 2.1% for control; 96.4 +/- 1.8% for circulating LPS-Rx; and 78.7 +/- 7.8% (P less than 0.05 compared to control) for BAL PMNs. Total numbers of yeast particles per 100 PMN are 270 +/- 64 for control, 300 +/- 42 for circulating LPS-Rx, and 170 +/- 45 (P less than 0.05 compared to control) for BAL PMN. CONCLUSIONS: (1) Intraalveolar (BAL) PMNs have decreased adherence; (2) nonadherent PMNs have decreased uptake of yeast; (3) BAL PMNs, overall, have a significantly decreased uptake of yeast; (4) this depression in BAL PMN phagocytosis may partially explain the known decreased rate of bacterial clearance in injured lungs and the increased risk of pulmonary sepsis with adult respiratory distress syndrome.

Animals↗
PubMed1988

Risk factors for urethral injuries in men with traumatic pelvic fractures.

Urethral injuries are commonly associated with pelvic fractures. The prompt recognition and appropriate management of these injuries may significantly impact subsequent morbidity, yet few studies have addressed the identification of the risk factors for urethral injury in men with pelvic fractures. We reviewed retrospectively the records of 405 men with pelvic fractures seen at our medical center, including 21 (5 per cent) with urethral injuries. Of the 21 men 14 (67 per cent) had fractures involving a pubic ramus and a sacroiliac joint, and 12 (57 per cent) had no physical signs (blood at the urethral meatus, perineal hematoma or a high-riding prostate) that would suggest a urethral injury. The likelihood for the presence of physical signs is directly related to the interval since injury. We believe that men with the combination of rami fractures and sacroiliac disruption should undergo retrograde urethrograms before urethral instrumentation, and that physical signs are unreliable indications for urethral injuries, especially soon after the injury.

Fractures, Bone↗
PubMed1987

Neutrophil function in a rat model of endotoxin-induced lung injury.

Polymorphonuclear neutrophil leukocytes (PMNs) are known to cross the alveolar-capillary barrier and enter the alveolus in acute adult respiratory distress syndrome (ARDS). The pathogenic role of PMNs in both the acute lung injury and subsequent infectious susceptibility in ARDS is not clear. In the present study we investigated the functional status of various neutrophil populations using a chronic, endotoxemia-induced ARDS model. Rats infused with Escherichia coli endotoxin for three days develop an acute lung injury with a histologic picture closely resembling human ARDS. The PMNs recovered from the circulation and by bronchoalveolar lavage were compared with normal rat PMNs. In endotoxemic animals, superoxide production was markedly enhanced in circulating PMNs, indicating production of high levels of potentially cytotoxic oxygen intermediates, while myeloperoxidase activity was decreased in both circulating and lavage PMNs, indicating depressed myeloperoxidase-dependent antimicrobial activity.

Animals↗
PubMed1987

Incidence and effect of hypothermia in seriously injured patients.

Hypothermia is a well recognized consequence of severe injury, even in temperate climates, and the physiologic consequences of hypothermia are known to be detrimental. To analyze the frequency and risk factors for hypothermia and its effect on patient outcome, we prospectively studied 94 intubated injured patients at a regional trauma center during a 16-month period. Esophageal temperature probes were placed in the field or ER and core temperatures (T) were followed for 24 hours or until rewarming. Patients were designated as normothermic (greater than 36 degrees C), mildly hypothermic (34 degrees C-36 degrees C) or severely hypothermic (less than 34 degrees C) based on initial T. The risk factors for hypothermia evaluated included age, severity and location of injuries, blood alcohol level, blood transfusion requirements, and time spent in the field, ER, or OR. The average initial T was 35 degrees C, with no seasonal variation. Injury severity and survival correlated with severe hypothermia. Normothermic patients had an average ISS of 28 with a 78% survival. Severely hypothermic patients had an average ISS of 36 with a 41% survival (p less than 0.05). Patient age strongly correlated with outcome although there was no relationship between age and initial temperature. Sixty-two per cent of patients tested were positive for blood alcohol, and one half were legally intoxicated (BAC greater than 100 mg%). However, no consistent correlation was found between alcohol intoxication and initial temperature or patient survival. Blood transfusion requirements paralleled injury severity and patients receiving greater than 10 unit transfusions had significantly lower core temperature (p less than 0.05). The average temperature change was positive in the ER, OR, and ICU with time to rewarming correlating with the aggressiveness of warming measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

The epidemiology of logging injuries in the northwest.

Logging is among the most hazardous forms of employment. However, a comprehensive review of severe logging injuries and their outcome has apparently not been previously undertaken. In the present study we review 51 consecutive injured loggers requiring transfer to a regional Level I trauma center. The average age was 34 years and the mode of injury in 67% was being struck by a falling or rolling log. Orthopedic intervention was required most frequently (49%), with neurologic injury in 43%. Two patients died (4%), both secondary to severe head injury, and both survived less than 24 hours. Importantly, while most severely injured patients survived, they required long hospitalizations and had a 58% permanent disability, with more than half of these being brain or spinal cord related. Although the overall number of workers involved in logging is small, the young average age, the work years lost, and the high risk of permanent disability support continued strong efforts to improve overall safety. Particularly, the high incidence of head injury argues strongly for improved and increased use of safety helmets, which may significantly impact the mortality and morbidity of logging accidents.

Accident Prevention↗
PubMed1986

Is macrophage-induced microthrombosis during endotoxemia dependent on prostaglandin synthesis?

Steroids and nonsteroidal anti-inflammatory drugs (NSAID), in addition to inhibiting prostaglandin synthesis, have recently been shown to block production of procoagulant activity (PCA) by alveolar macrophages (A-M phi). This inhibition may ameliorate one deleterious effect of endotoxin (LPS), since LPS-induced PCA may contribute to the diffuse microvascular thrombosis (DIC) and subsequent organ failure seen in endotoxemia. However, the results of treatment of endotoxemia with steroids of NSAID are variable or short-lived. To help elucidate the basis for these results, the effect of these agents on production of PCA by another M phi population, the hepatic M phi (H-M phi PCA is functionally discrete from A-M phi PCA) was evaluated. Four agents, (hydrocortisone, indomethacin, ibuprofen and acetylsalicylic acid (ASA)) used to both block production of prostaglandins and ameliorate the deleterious effects of LPS in vivo were tested on the production of rabbit M phi PCA in vitro in homogeneous cultures. PCA was measured by a standardized one-step coagulation assay. Treatment with LPS (1 to 10 g/ml) produced maximal stimulation of PCA production with a peak at 8 hr with PCA levels 20- to 30+-fold higher than controls. The effect of pretreatment (T-10 min) of M phi cultures with the various inhibitors on PCA production at 8 hr post-LPS was evaluated, (N = 6 to 10 experiments).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Developments in the resuscitation of critically ill surgical patients.

Despite the fact that many new exciting prospects are on the horizon, volume support remains the cornerstone of resuscitation of the critically ill surgical patient. Their limitations not withstanding, balanced electrolyte solutions, properly used, are the most efficacious choice in the majority of patients. The patient's eventual survival depends not only on skillful resuscitation but on the ability to identify and correct the underlying cause.

Adenosine Triphosphate↗
PubMed1985

Idiopathic pulmonary fibrosis in adult respiratory distress syndrome. Diagnosis and treatment.

Ten consecutive patients who presented initially with adult respiratory distress syndrome, and who did not respond to conventional treatment, underwent open lung biopsy early in the course of their illness. Idiopathic pulmonary fibrosis was diagnosed and aggressive treatment with methylprednisolone sodium succinate and nutritional support was initiated. Eight patients survived and have not required long-term corticosteroid therapy. Previous reports have documented a mortality of greater than 85% with this particular syndrome of idiopathic pulmonary fibrosis in adult respiratory distress syndrome.

Adolescent↗
PubMed1985

Correlation of hemodynamic variables with transcutaneous PO2 measurements in critically ill adult patients.

Transcutaneous oxygen (PtcO2) monitoring with miniaturized heated electrodes has been shown to continuously track arterial oxygen tension (PaO2) noninvasively in stable infants. However, the correlation between the two is less marked in unstable adults, and PtcO2 appears to be additionally influenced by perfusion. The ability of PtcO2 to detect alterations in cardiac index (CI) was evaluated in 19 critically ill adult patients. The PtcO2 was found to be influenced by the PaO2, the CI, and local vascular tone, with a rapid response time to changes in these variables. All instances of improvement in PtcO2 readings were associated with improvement in PaO2 or hemodynamic status. Because of its high sensitivity, continuous noninvasive PtcO2 monitoring should allow reduction in routine PaO2 and CI determinations. However, a decrease in PtcO2 requires immediate in-depth evaluation of the patient's PaO2 and CI because of its lack of specificity.

Adult↗
PubMed1984

Potential for endotoxin-activated Kupffer's cells to induce microvascular thrombosis.

The potential contribution of Kupffer's cells, le, hepatic macrophages (HM phi s) to the diffuse microvascular thrombosis seen during septicemia was evaluated by measuring the ability of a homogeneous population of explanted HM psi s to express procoagulant activity (PCA). Addition of as little as 100 ng/mL of endotoxin stimulated a 30-fold increase over control values of PCA within eight hours. This PCA was membrane associated and functioned externally to the macrophage. Sensitivity to heat (56 degrees C) and diisopropyl fluorophosphate differentiated this PCA from typical tissue thromboplastin activity. The increase in PCA was blocked by pretreatment with warfarin sodium (a phytonadione blocker) and could be restored by addition of phytonadione. These studies showed that endotoxin induces in HM psi s a significant increase in PCA, functioning like coagulation factor VII. These results support a role for Kupffer's cells in the initiation of microvascular thrombosis in endotoxemia.

Animals↗
PubMed1984

Laparotomy for intra-abdominal sepsis in patients in an intensive care unit.

Patients in an intensive care unit who have intra-abdominal (IA) infections producing clinical deterioration in their conditions require urgent intervention. However, detection is often difficult. To define preoperative criteria for, and improve the specificity of, laparotomy, we reviewed 100 explorations in 71 patients with suspected IA sepsis. Eighty-one explorations demonstrated an infected or ischemic process; 19 were negative. Preoperative features associated with a positive laparotomy were as follows: (1) objective evidence by physical examination, ultrasonography, or computed tomography suggesting an IA focus (89%); (2) septic shock (80%); and (3) positive blood cultures (95%). Absence of these features significantly lowered the accuracy of exploration. Septic shock or bacteremia had a 90% mortality regardless of findings at exploration. The best accuracy (89%) and survival (51%) rates were achieved with "directed" exploration before septic shock or bacteremia. Early use of sensitive detection techniques that permit directed laparotomy before septic deterioration should improve survival.

Abscess↗
PubMed1984

Microthrombosis during endotoxemia: potential role of hepatic versus alveolar macrophages.

Macrophages (M phi) produce multiple inflammatory mediators which may contribute to the pathophysiological processes seen during sepsis. Since diffuse microthrombosis has been implicated as a potential etiology for organ dysfunction and failure in sepsis, the present study examined the production of procoagulant activity (PCA) by M phi in response to endotoxin, characterized the activity, and evaluated methods to modify the response. Since hepatic and pulmonary dysfunction is a common complication of sepsis, rabbit M phi were isolated from both pulmonary (A-M phi) and hepatic (H-M phi) sites. Both M phi populations produced PCA in response to endotoxin in vitro. There is a rapid rise in activity with a peak at 20- to 30+ fold over background levels at 8 hr poststimulation. Although similar in their ability to enhance coagulation, the two M phi PCAs were shown to differ markedly in other biochemical and functional assays. The A-M phi PCA in contrast to the H-M phi PCA, was resistant to heat inactivation, serine protease inhibition, and warfarin pretreatment, while indomethacin (a prostaglandin synthesis inhibitor) blocked A-M phi PCA production but not the H-M phi response. Corticosteroids totally blocked PCA production by both M phi populations. Endotoxin, therefore, induces a rapid increase in M phi PCA, and the magnitude and rapidity of the response argue for a potentially significant pathophysiologic role, in vivo. Although derived from a common progenitor, A-M phi and H-M phi produce a functionally discreet PCA. This differential response may partially explain the contradictory results obtained in studies using various cellular metabolism inhibitors, e.g., indomethacin and steroids.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗
PubMed1984

The influence of ethanol intoxication on outcome of injured motorcyclists.

Previous reports have failed to demonstrate a statistically significant adverse effect of acute ethanol intoxication in the well-resuscitated trauma patient. In the present study the prevalence of acute alcohol intoxication and its effect on outcome was analyzed in a homogenous population of young, previously healthy motorcycle accident victims (N = 134). The incidence of intoxication was 25%. The intoxicated cyclists were at fault for the accident 50% more often than the nonintoxicated cyclists and were found to wear helmets one third as frequently. Furthermore, the protective effect of helmet use as seen in the nonintoxicated group was lost in the intoxicated group, who sustained head injuries twice as frequently. Only patients with critical head injuries died and, although the ISS levels of those dying were similar in the two groups, the mortality following the critical head injury was twice as high among intoxicated patients (80 vs. 43%). Overall, the intoxicated group had a fourfold increased mortality rate. Thus, although intoxicated motorcyclists comprised 25% of the total population, they represent a mere 9% of the helmet-wearing population, and, in contrast, 39% of the severely head-injured victims and a majority (57%) of the mortality rate.

Accidents, Traffic↗
PubMed1984

Retroperitoneal giant lymph node hyperplasia. A case report and review of the literature.

Giant lymph node hyperplasia (GLNH) is a rare tumor. The authors have reviewed the literature and brought the reported total to 235 cases. There are two types of GLNH, a hyaline-vascular and plasma-cell type. The usual presentation is as an asymptomatic solitary mass, though multicentric lesions are found. Symptoms are most frequent with the plasma-cell type. A syndrome of anemia, growth retardation, and hypergammaglobulinemia is seen in the plasma-cell type in children. The etiology is unknown, though immunologic studies indicate a reactive phenomenon. Radiologic studies are nonspecific. Therapy is surgical excision, which is usually curative.

Adult↗