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Biomedical subjects

S E Ross

Publications and source records attributed to S E Ross.

At least 73 records · Page 4Linked to original sources
PubMed1993

Interactions of mycoplasmas with B cells: antibody production and nonspecific effects.

Interactions between mycoplasmas and B cells consist primarily of the development of specific antibody and of nonspecific interactions with B lymphocytes or antibody. Antibody responses are important in the resistance to mycoplasmal disease in both humans and animals. However, the ability of mycoplasmas to survive in their host despite vigorous responses suggests that these play a limited role in the host's recovery from infection. Antibody also may prevent dissemination of mycoplasmal infections from mucosal sites and may account for the appearance of systemic mycoplasmal infections in immunocompromised patients. In some cases, antibody responses may contribute to disease pathogenesis through the development of hypersensitivity responses or the deposition of immune complexes. In addition, nonspecific interactions between mycoplasmas and B lymphocytes have been implicated in disease pathogenesis, possibly leading to autoimmune reactions, modulation of immunity, and/or promotion of lesion development. For example, several mycoplasmas, including Mycoplasma pneumoniae and Mycoplasma pulmonis, are able to activate B cells polyclonally in vitro and in vivo, but the mechanisms and consequences of these responses have yet to be defined. In addition to activating B lymphocytes, mycoplasmas are capable of producing chemotactic factors, Fc receptors, and immunoglobulin proteases that may also be involved in lesion development and/or survival of the organisms. Thus, both specific and nonspecific interactions of mycoplasmas with B cells can have important effects on disease progression, especially since many mycoplasmal infections are chronic and the cumulative effect of these interactions may be substantial.

Animals↗
PubMed1993

Bacterial translocation occurs in humans after traumatic injury: evidence using immunofluorescence.

UNLABELLED: We evaluated the occurrence of bacterial translocation (BT) in humans after traumatic injury. Twenty trauma patients (18 with blunt trauma) requiring celiotomy and without hollow viscus injury were studied. After surgical hemostasis and repair, portal venous blood (PVB) was sampled for culture. Additionally, a mesenteric lymph node (MLN) was harvested for culture and indirect immunofluorescence analysis using, first, mouse monoclonal antibody to E. coli beta-galactosidase, then goat anti-mouse immunoglobulin G (IgG). Injury Severity Score (ISS), Trauma Score (TS), and period of hemorrhagic shock (HS; systolic BP < 90 mm Hg with blood loss > 500 mL) were recorded before specimens were obtained. RESULTS: Fifteen patients initially had HS (mean period of 60 minutes). Mean TS and ISS were 10 and 29, respectively. Seven patients did not have HS (mean TS and ISS, 10 and 13). Three patients received antibiotics preoperatively. Portal venous blood culture produced positive results in only three patients (two with HS) and culture of the MLN specimen was positive in one. However E. coli beta-galactosidase was detected within the cytoplasm of macrophages in all MLNs. One patient developed multiple organ failure. CONCLUSION: Bacterial translocation occurs in humans following traumatic injury and may be independent of HS. Culture techniques may not detect BT since organisms may have been phagocytized by macrophages. The clinical significance of BT in trauma patients remains unclear.

Cell Movement↗
PubMed1993

Delayed and progressive brain injury in closed-head trauma: radiological demonstration.

The importance of delayed or secondary brain insults in the eventual outcome of closed-head trauma has been documented in experimental models. To understand this phenomenon in the clinical setting, we studied a series of head-injured patients in whom multiple cranial computed tomographic (CT) scans were obtained. Patients whose follow-up CT studies revealed new intracranial lesions or worsening, compared with admission findings, were considered to have delayed cerebral injury. One hundred forty-nine (44.5%) of 337 consecutively studied patients developed delayed brain injury. There were highly significant associations (P < 0.001) between the appearance of delayed cerebral insults and the severity of the initial brain injury, the need for cardiopulmonary resuscitation in the field, the presence of coagulopathy at admission, and subdural hematoma on the initial CT scan. In addition, delayed injury was associated (P < 0.001) with higher mortality, slowed recovery, and poorer outcome at 6 months. Delayed brain injury was not significantly associated with patient age, sex, injury mechanism, associated injury, the need for endotracheal intubation in the field, early talking, CT abnormality other than intracranial hematoma, or type of residual neurological deficits. We used multiple regression analysis to explore the relationship between severity of injury, delayed insults, and outcome. As expected, the severity of the initial brain trauma contributed significantly to neurological outcome. The presence of delayed cerebral injury makes the outcome dramatically worse for each category of initial injury severity. The relationship between initial and secondary brain injury is discussed.

Adolescent↗
PubMed1993

Complications of anticoagulation for pulmonary embolism in low risk trauma patients.

Trauma patients are at significant risk for deep venous thrombosis (DVT) and pulmonary embolism (PE). Anticoagulation is standard therapy for DVT/PE, but may cause severe complications. We reviewed the course of 70 trauma ICU patients treated over a 28-month period. Thirty-six patients (51.4 percent) were treated by continuous IV heparin and/or oral warfarin. Of these, 13 patients (36 percent) developed complications requiring termination of anticoagulation. These included recurrent PE (four), subdural hematomas (three), hemothorax (two), heparin-induced thrombocytopenia (one), hemorrhagic pericardial effusion (one), retroperitoneal hematoma (one), and sudden unexplained drop in hemoglobin and shock (one). All patients with subdural hematomas had no prior evidence of head injury on brain computed tomography. All patients with recurrent PE received adequate anticoagulation therapy. Age > 55 was associated with increased risk of complications (8 of 13; p = .02:chi 2). Thirty-four other patients (48.6 percent) received inferior vena caval filters with no related complications or deaths. Anticoagulation for DVT/PE should be used selectively in trauma patients and avoided in elderly patients. Such patients should undergo early caval filter placement.

Adult↗
PubMed1992

Abbreviated injury scaling of head injury as a prognostic tool for functional outcome.

The use of Abbreviated Injury Scaling for the head region (HAIS) was evaluated as a prognostic index of functional outcome in 503 consecutive patients with severe injury to the brain who survived initial resuscitation. Although a strong statistical relationship between HAIS and outcome as measured by the Glasgow Outcome Scale was demonstrated, its clinical usefulness is limited. HAIS may be most useful as a classifier for comparative studies of populations and for the evaluation of therapeutic modalities.

Abbreviated Injury Scale↗
PubMed1992

Clinical predictors of unstable cervical spinal injury in multiply injured patients.

All victims of major blunt trauma have been said to be at risk of cervical spinal injury. In a prospective study of 410 such patients at our institution, we identified 13 patients (6.12 per cent) with unstable cervical spines. Loss or defect of consciousness following injury (regardless of duration), neurological deficit consistent with cervical cord or nerve root injury and neck tenderness were significantly predictive of an unstable cervical spine. Immediate radiographic investigation of the cervical spine is mandatory in such patients, but may not be required in patients without these signs.

Adolescent↗
PubMed1992

Effect of daytime protein restriction on nutrient intakes of free-living Parkinson's disease patients.

Studies have shown that severe daytime restriction of dietary protein improves the efficacy of L-dopa and reduces response fluctuations in some Parkinson's disease (PD) patients. This study investigated the nutritional adequacy of the daytime restricted-protein diet. Eleven free-living PD patients suffering from unpredictable response fluctuations to L-dopa were counseled to limit protein intake to approximately 10 g before 1700. Three sets of 6-d food records obtained during the 8-wk study showed that while on the test diet, mean intakes of most nutrients remained above the recommended nutrient intakes, although significant decreases occurred in protein, calcium, iron, phosphorus, riboflavin, and niacin intakes. The impact of the test diet on nutritional status as evaluated by changes in body weight and serum prealbumin was small. We conclude that healthy and highly motivated patients can maintain adequate intakes of most nutrients while restricting daytime protein intake. However, nutrient intakes might be compromised in patients whose regular diets are marginally adequate.

Aged↗
PubMed1992

Blunt colonic injury--a multicenter review.

During the past decade there has been a shift in the management of injuries of the colon to primary repair without a protective diverting colostomy. Unfortunately, reports concerning this practice contain relatively few patients with blunt trauma and it is unclear whether the principles established for penetrating injury should be applied in the setting of blunt colon injury. A retrospective review of 54,361 major blunt trauma patients admitted to nine regional trauma centers from January 1, 1986, through December 31, 1990, was conducted. Statistical analysis of the data collected regarding 286 (0.5%) of these patients who suffered colonic injury revealed: (1) injury to the colon is found in more than 10% of patients undergoing laparotomy following blunt trauma; (2) available diagnostic modalities are unreliable in detecting isolated colonic pathology; (3) primary repair of full-thickness injuries or resection and anastomosis may be safely performed without diversion; (4) gross fecal contamination is the strongest contraindication to primary repair. Further, delay of surgery, shock, and the timing of antibiotic administration were not associated with significantly increased morbidity.

Abbreviated Injury Scale↗
PubMed1992

The clinical utility of computed tomographic scanning and neurologic examination in the management of patients with minor head injuries.

The evaluation and management of patients with minor head injury (MHI: history of loss of consciousness or posttraumatic amnesia and a GCS score greater than 12) remain controversial. Recommendations vary from routine admission without computed tomographic (CT) scanning to mandatory CT scanning and admission to CT scanning without admission for selected patients. Previous reports examining this issue have included patients with associated non-CNS injuries who confound the interpretation of the data and affect outcome. We hypothesized that patients with MHI and no other reason for admission with normal neurologic examinations and normal CT scans would have a negligible risk of neurologic deterioration requiring surgical intervention. To validate this hypothesis we studied 2766 patients with an isolated MHI admitted to seven trauma centers between January 1, 1988, and December 31, 1991. There were 1898 male patients and 868 female patients; injury was blunt in 99%. A neurologic examination and a CT scan were performed on 2166 patients; 933 patients had normal neurologic examinations and normal CT scans and none required craniotomy; 1170 patients had normal CT scans and none required craniotomy; 2112 patients had normal neurologic examinations and 59 required craniotomy. The sensitivity of the CT scan was 100%, with positive predictive value of 10%, negative predictive value of 100%, and specificity of 51%. The use of CT alone as a diagnostic modality would have saved 3924 hospital days, including 814 ICU days, and $1,509,012 in hospital charges. Based on these data, we believe that CT scanning is essential in the management of patients with MHI and that if the neurologic examination is normal and the scan is negative patients can be safely discharged from the emergency room.

Adolescent↗
PubMed1992

Continuous pulse oximetry and the diagnosis of pulmonary embolism in critically ill trauma patients.

The diagnosis of pulmonary embolism (PE) may be difficult to establish in trauma patients, particularly those who are unresponsive or mechanically ventilated. Based on a prior retrospective study, we hypothesized that patients monitored by continuous pulse oximetry who experienced a 10% or greater sudden sustained drop in arterial oxygen saturation (SaO2) without a change in static lung compliance (Cst) were most likely to have had a PE. We followed SaO2 in 972 patients admitted to our trauma ICU during the 18-month period ending in December 1990. Forty-eight patients (5%) with SaO2 changes, but no Cst changes, were evaluated for suspected PE using pulmonary arteriography (PA). Of these, 21 (44%) had a positive PA study. All patients with a positive PA had either clear chest roentgenograms or no change in underlying pulmonary pathologic processes. Of the remainder, 26 had evidence of a new pathologic entity on chest roentgenograms and only one patient had a SaO2 decrease, no change in Cst, and a negative PA. All mechanically ventilated trauma patients should have SaO2 monitored continuously. Patients with a > 10% drop in Sao2 with no change in Cst and no new roentgenographic chest findings should undergo PA. Based on our experience, this approach would yield a sensitivity, specificity, and predictive value of 100%, 99.9%, and 95%, respectively, for the diagnosis of clinically significant PE.

Adolescent↗
PubMed1992

Mycoplasma pulmonis possesses a novel chemoattractant for B lymphocytes.

Mycoplasma pulmonis causes chronic murine respiratory mycoplasmosis, which is characterized by extensive peribronchial and perivascular infiltration of mononuclear cells, including B lymphocytes. B-lymphocyte recruitment into sites of inflammation is presently poorly understood but must involve directed chemotaxis of these cells in response to some external recruitment stimulus. In these studies, picogram amounts of M. pulmonis membrane protein were found to possess potent chemoattractant activity for resting rat B lymphocytes. This report is the first description of a bacterially derived chemoattractant for B lymphocytes and offers a unique opportunity to study regulation of B-lymphocyte recruitment to a site of chronic pulmonary inflammation. Furthermore, M. pulmonis membrane activation of fresh rat serum was found to produce a potent stimulus for recruitment of peritoneal and alveolar macrophages. M. pulmonis-mediated recruitment of lymphocytes and macrophages may play a significant role in the pathogenesis of murine respiratory mycoplasmosis, a role in which organisms on the bronchiolar epithelial surfaces may release proteins which can directly or indirectly promote chemotaxis of inflammatory cells from the circulation.

Animals↗
PubMed1992

Infection-induced airway fibrosis in two rat strains with differential susceptibility.

Chronic infections play a significant role in the morbidity and mortality of patients with chronic airflow limitation. By stimulating airway inflammation, persistent infection has the potential to cause airway fibrosis. However, in patient this condition is most typically found in lungs damaged by other factors, such as smoking, abnormal secretions, or barotrauma. We report the characterization of Mycoplasma pulmonis infection-induced lung fibrosis in two immunocompetent rat strains with no preexisting lung disease. The fibrosis was predominantly in the airways, as demonstrated by the findings for infected animals of increased airway inflammation, airway fibrosis, and airway wall thickness, which correlated with the collagen content of the lungs. Also, the physiological alterations were the opposite of those found in interstitial fibrosis, with a positive correlation between lung compliance and collagen content. The airway fibrosis was noted earlier and to a greater extent in Lewis rats than in Fisher rats, and this result apparently was related to regulation of the inflammatory response. Airway wall thickness, airway inflammation, and airway fibrosis are commonly reported in tissue specimens from patients with chronic airway diseases and have been shown to correlate with airflow limitation in patients with chronic obstructive pulmonary disease. Thus, this model may be useful in furthering our understanding of the role of chronic infection and airway inflammation in airflow obstruction.

Analysis of Variance↗
PubMed1992

Delayed brain injury after head trauma: significance of coagulopathy.

We reviewed the records of 253 patients with head injury who required serial computed tomographic (CT) scans; 123 (48.6%) developed delayed brain injury as evidenced by new or progressive lesions after a CT scan. An abnormality in the prothrombin time, partial thromboplastin time, or platelet count at admission was present in 55% of the patients who showed evidence of delayed injury, and only 9% of those whose subsequent CT scans were unchanged or improved from the time of admission (P less than 0.001). Among patients developing delayed injury, mean prothrombin time at admission was significantly longer (14.6 vs. 12.6 s, P less than 0.001) and partial thromboplastin time was significantly longer (36.9 vs. 29.2 s, P less than 0.001) than patients who did not have delayed injury. If coagulation studies at admission were normal, a patient with head injury had a 31% risk of developing delayed insults. This risk rose to almost 85% if at least one clotting test at admission was abnormal (P less than 0.001). We conclude that clotting studies at admission are of value in predicting the occurrence of delayed injury. If coagulopathy is discovered in the patient with head injury early follow-up CT scanning is advocated to discover progressive and new intracranial lesions that are likely to occur.

Adolescent↗