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Biomedical subjects

J Barrett

Publications and source records attributed to J Barrett.

At least 181 records · Page 10Linked to original sources
PubMed1995

Central venous oxygen saturation, arterial base deficit, and lactate concentration in trauma patients.

Our object was to explore the usefulness of central venous oxygen saturation, arterial base deficit, and lactate concentration in the evaluation of trauma patients. In busy urban trauma centers, limited operating room availability may necessitate that certain hemodynamically stable patients experience some delay between diagnosis of injury and surgery. Because hemodynamic compromise may occur before operation is undertaken, some means of identifying those patients who have the most severe injuries or who are at greatest risk for hemodynamic instability would be useful. We prospectively studied 40 patients with operative truncal injuries admitted to the Cook County Trauma Unit, Chicago, to examine the usefulness of postresuscitation central venous oxygen saturation (ScvO2), arterial lactate concentration, and arterial base deficit in this regard. Preoperative hypotension occurred in 12.5 per cent of these initially stable patients. ScvO2 did not significantly correlate with any of the parameters of blood loss and severity of injury examined. However, both base deficit and lactate concentration correlated with transfusion requirements; in addition, base deficit correlated with trauma score, and lactate correlated with peritoneal shed blood volume. Our data suggest that, after resuscitation, arterial base deficit and lactate concentration may be better indicators of blood loss than is ScvO2.

Abdominal Injuries↗
PubMed1995

Aspiration of free blood from the peritoneal cavity does not mandate immediate laparotomy.

The objective was to establish the relationship between the aspiration of free blood (+ASP) versus diagnostic peritoneal lavage (DPL), abdominal injury severity, hemodynamic instability, and the need for immediate operative intervention. We prospectively compared the significance of +ASP to +DPL in our level I trauma center. Consecutive patients received sequential needle tap, catheter aspiration (ASP), and DPL. If gross blood was withdrawn during the tap or ASP, it was returned to the peritoneal cavity before completing the DPL. The DPL was considered positive if there were > 100,000 RBCs for blunt injuries or anterior abdominal stab wounds, or > 10,000 RBCs for other penetrating injuries. During a 12-month period, 566 patients fulfilled the study criteria; they were 50 per cent blunt and 50 per cent penetrating trauma. There were 70 patients with both +ASP/+DPL, 30 with -ASP/+DPL and 4 with +ASP but -DPL. Exploratory laparotomy was performed on these 104 patients (18.4%), 22 of which were considered nontherapeutic. The ATI was statistically higher in the +ASP patients (14.9 +/- 12.9 versus 8.5 +/- 8.2, P < 0.05) but was not clinically different. Overall injury severity and hemodynamic stability were not different in the two groups. The sensitivity of DPL at detecting intra-abdominal injury was higher than the ASP group (98% versus 72%), but the specificities were equal (98%). Because +ASP patients are not more critically injured or unstable than +DPL patients, and because DPL is more accurate in detecting the need for operative intervention, aspiration should be abandoned as part of the DPL procedure in patients with abdominal trauma.

Abdominal Injuries↗
PubMed1994

Relapse of chronic myeloid leukemia after allogeneic bone marrow transplant: the case for giving donor leukocyte transfusions before the onset of hematologic relapse.

Fourteen patients with chronic myeloid leukemia (CML) relapsing after allogeneic bone marrow transplant (BMT) were treated with leukocyte transfusions from the original marrow donor (sibling, n = 9; volunteer unrelated, n = 5). The relapse was defined at the molecular level in two cases, cytogenetically in five cases and hematologically in seven cases. Ten patients responded, seven of seven patients with cytogenetic/molecular relapse compared with three of seven with hematologic relapse (P < .03). All five recipients of cells from unrelated donors responded. Eight of the 10 responders have achieved polymerase chain reaction-negative status and this persisted in three patients for more than 2 years; no responder has shown sign of relapse. Reversible marrow aplasia occurred in two patients, both treated in hematologic relapse. Severe graft-versus-host disease occurred in four patients and was fatal in one. We confirm previous reports that donor leukocyte transfusions are effective in the management of CML in relapse after BMT. In this series, therapeutic intervention before the onset of hematologic relapse was associated with an increased likelihood of response and no marrow aplasia.

Adult↗
PubMed1994

The epidemiology of diagnosed pulmonary embolism and deep venous thrombosis in the elderly.

BACKGROUND: There are no studies that define the basic epidemiology of pulmonary embolism (PE) and deep venous thrombosis (DVT) in the elderly. This project was undertaken to provide that information. METHODS: We obtained all Medicare claims during the period 1986 through 1989 from a random 5% sample of US Medicare enrollees. By selecting codes used for diagnoses and treatment, we identified 7174 cases of PE and 8923 cases of DVT. These cohorts were analyzed to provide incidence by age, race, sex, and geographic location; frequency of invasive treatment; frequency of PE after treatment for DVT; frequency of recurrence of PE; and survival after diagnosis. RESULTS: Annual incidence rates per 1000 at age 65 to 69 years for PE and DVT were 1.3 and 1.8, respectively. Both rates increased steadily with age to 2.8 and 3.1 by age 85 to 89 years. For PE, women had lower rates than men (adjusted relative risk, 0.86; 95% confidence interval, 0.82 to 0.90), and blacks had higher rates than whites (adjusted relative risk, 1.25; 95% confidence interval, 1.15 to 1.36). For DVT, the associations with gender and race were weaker and in the opposite direction. Pulmonary embolectomy was done in 0.2% of cases of PE; interruption of the vena cava was done in 4.4% of cases of PE and in 2% of cases of DVT. Thrombectomy was done in 0.3% of all cases. Pulmonary embolism occurred in 1.7% of patients with DVT within 1 year of hospital discharge for initial treatment. The 1-year recurrence rate for PE was 8.0%. In-hospital mortality associated with PE and DVT was 21% and 3%, respectively. One-year mortality was 39% and 21%, respectively. CONCLUSIONS: Pulmonary embolism and DVT are common problems in the elderly. Both increase with age, but the effects of race and sex are small. Current treatment patterns appear to be effective in preventing both PE after DVT and recurrence of PE. Both are associated with substantial 1-year mortality, suggesting the need to understand the role of associated conditions as well as the indications for prophylaxis and the methods of treatment.

Black or African American↗
PubMed1994

Racial differences in fracture risk.

Blacks appear to have a lower risk of fractures than whites, but there has been little research regarding racial differences in the risk of fractures at sites other than the hip. We used Medicare claims to investigate the risks of fractures of the hip, distal forearm, proximal humerus, and ankle among American whites and blacks over 65 years old. Each of these fractures occurred more frequently in women than in men and (except for ankle fracture) displayed an increase in risk with age. Blacks had a lower risk than whites, although these differences were smaller for fractures of the ankle and were less pronounced among men. The most likely explanation for this is a constitutional or metabolic factor prevalent in blacks that particularly influences the risk of osteoporotic fractures in women.

Aged↗
PubMed1994

Control of breathing patterns and abdominal muscles during graded loads and tilt.

Tilting from supine to upright purportedly enhances both segmental and pulmonary proprioceptive feedback, whereas an expiratory threshold load (ETL) preferentially enhances pulmonary feedback. To test this we studied 13 adults when supine and 60 degrees and 90 degrees head up. We measured tidal volume, inspiratory duration (TI), and expiratory duration (TE) from flow; estimated end-expiratory lung volume from inspiratory capacity; and determined burst amplitudes and durations from abdominal electromyograms (EMGs). ETLs were incremented from 0 (control) to 25 cmH2O in 5-cmH2O steps. Tidal volume was significantly increased by ETL but was unaffected by body position. Every load prolonged TE, whereas TI remained unchanged. When subjects were supine, abdominal EMGs were silent but became tonically active when subjects were upright. During ETL, abdominal activity became rhythmical and phase locked to expiration. Bursts amplitudes were enhanced with each increment in ETL, but burst durations did not change even though TE was prolonged. The altered breathing pattern and active expiration augmented inspiratory flow and decreased end-tidal PCO2. Responses were greatest when subjects were 90 degrees head up. The load-related increments in abdominal recruitment, with no change in burst durations, fit the concept of two central pattern generators: one controlling pattern and the other controlling rhythm of the central respiratory drive.

Abdominal Muscles↗
PubMed1994

Internal validation of Medicare claims data.

The Medicare database is commonly used for epidemiology and health services research, but validation of its data by chart review or questionnaire may be difficult and expensive. Since hospital and physician bills are independent in Medicare, however, these two data sources can be used to supplement and corroborate each other. This "internal validation" is illustrated here for hip fracture and prostatectomy. Agreement of the hospital and physician data streams regarding site of hip fracture (neck vs other), treatment of hip fracture (internal fixation vs arthroplasty), and type of prostatectomy (transurethral resection of prostate, open, or radical) was excellent, with percentage of agreement generally between 89% and 99%, and kappa statistics typically between 0.74 and 0.95. When validation with outside data sources is not readily available, such internal validation of Medicare data may be valuable.

Abstracting and Indexing↗
PubMed1994

Bacterial translocation following abdominal trauma in humans.

Bacterial translocation in humans has been identified only with small bowel obstruction and in trauma patients. Our aim was to determine whether the occurrence of bacterial translocation correlates with clinical outcome in trauma patients. All patients requiring exploratory celiotomy for abdominal trauma over a 2-month period were considered for the study. Gross fecal contamination of the abdomen was the only exclusion criterion. Five patients with small bowel injuries without obvious contamination were included. Patients received preoperative antibiotics. Once surgical hemostasis and injury repair were complete, two mesenteric lymph nodes were harvested--one for quantitative culture, the other for electron microscopic evaluation. Postoperatively, patients were monitored for infection via temperature, white blood cell (WBC) count, and, when indicated, chest X-ray (CXR) and culture. Statistical analysis utilized ANOVA (P < 0.05 significant) and linear regression. Sixteen patients were included in the study. Fifteen patients sustained penetrating abdominal trauma, one blunt. Six patients presented in Class I hemorrhagic shock, four in Class II, and two in Class III. The remaining four were not in hemorrhagic shock. Thirteen patients demonstrated bacterial translocation: one by culture alone, nine by electron microscopy, and three by both culture and electron microscopy. Statistical analysis of these three groups and patients without evidence of infection failed to reveal significant difference in average age, injury severity, hospital days, or incidence of postoperative infection. Bacterial translocation occurs following abdominal trauma in humans. Electron microscopic evaluation of mesenteric lymph nodes demonstrated that the incidence of translocation is greater than anticipated by culture alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Injuries↗
PubMed1993

Racial differences in the incidence of cardiac arrest and subsequent survival. The CPR Chicago Project.

BACKGROUND: Differences between blacks and whites have been reported in the incidence of several forms of cardiovascular disease, including hypertension and stroke. We examined racial differences in the incidence of cardiac arrest in a large urban population and in subsequent survival. METHODS: We collected data on all nontraumatic, out-of-hospital cardiac arrests in Chicago from January 1, 1987, through December 31, 1988, and compared the incidence and survival rates for blacks and whites. We examined the association between survival and race and seven other known risk factors by logistic-regression analysis. We computed incidence rates by coupling our data with U.S. Census population data. RESULTS: Our study population comprised 6451 patients: 3207 whites, 2910 blacks, and 334 persons of other races. The incidence of cardiac arrest was significantly higher for blacks than for whites in every age group. The survival rate after cardiac arrest was 2.6 percent in whites, as compared with 0.8 percent in blacks (P < 0.001). Blacks were significantly less likely to have a witnessed cardiac arrest, bystander-initiated cardiopulmonary resuscitation, or a "favorable" initial rhythm or to be admitted to the hospital. When they were admitted, blacks were half as likely to survive. The association between race and survival persisted even when other recognized risk factors were taken into account. We did not find important differences between blacks and whites in the response times of the emergency medical services. CONCLUSIONS: The black community in our study was at higher risk for cardiac arrest and subsequent death than the white community, even after we controlled for other variables.

Adolescent↗
PubMed1993

Immunological characterization of the tumor-specific bcr/abl junction of Philadelphia chromosome positive chronic myeloid leukemia.

Recent developments in the understanding of the process of antigen presentation by major histocompatibility complex (MHC) molecules and their recognition by T-lymphocytes has led investigators to speculate that the hybrid bcr/abl fusion protein P210 present in chronic myeloid leukemia (CML) cells may generate leukemia-specific antigens recognized by T-cells. We used synthetic peptides representing the fusion region of P210 to study MHC class I and class II pathways of antigen recognition in normal subjects and patients with CML. We found that most normal individuals have a low proliferative response to 18mer fusion peptides representing the two alternative splicing variants b2a2 and b3a2, and a T-lymphocyte precursor frequency (HTLPf) characteristic of unprimed responders. No increase in HTLPf was found in CML patients after bone marrow transplantation (BMT), suggesting that peptide recognition does not form part of the graft-versus-leukemia process. In contrast, untransplanted patients with CML had very high HTLPf, suggesting an autologous but immunologically ineffective recognition of leukemia-specific peptides through HLA class II. Preliminary studies using the T2 cell line (which expresses HLA class I only in the presence of peptides binding to HLA-A2) indicate that nonapeptides spanning the breakpoint of the b2a2 and b3a2 variants of P210 do not bind to this particular class I molecule and are therefore unlikely to initiate class I mediated lymphocyte responses.

Antigen-Presenting Cells↗
PubMed1993

Sphingomyelin synthesis in Ascaridia galli.

Adult Ascaridia galli incorporate label from [U-14C] serine into various intermediates of sphingomyelin synthesis (ketosphinganine, sphinganine, sphingosine, ceramide and sphingomyelin). From the results it is concluded that A. galli possesses the five enzymes involved in sphingomyelin synthesis, namely: serine palmitoyltransferase, 3-ketosphinganine reductase, flavoprotein sphinganine reductase, sphingosine acyltransferase and ceramide choline phosphotransferase.

Animals↗
PubMed1993

Evidence for a G protein system in the tegumental brush border plasma membrane of Hymenolepis diminuta.

Guanine nucleotide-binding regulatory proteins (G proteins) mediate the transduction of signals from cell-surface receptors to intracellular effector enzymes. G protein alpha-subunits are routinely identified (and partially characterized) on the basis of their susceptibility to NAD(+)-dependent ADP-ribosylation NAD(+)-dependent ADP-ribosylation catalysed by cholera and/or pertussis toxins. Analysis of purified tegumental brush border plasma membrane from Hymenolepis diminuta by relevant methodologies has revealed the presence of a 42 kDa putative G protein alpha-subunit that is susceptible to ADP-ribosylation by both cholera and pertussis toxins. This polypeptide shows no definite resemblance to any of the four major mammalian G protein classes on the basis of M(r) and toxin-susceptibility. These results provide evidence for the existence of a tegumental G protein-linked signal transduction system in H. diminuta.

Animals↗
PubMed1993

Biochemical properties of cloned glutathione S-transferases from Schistosoma mansoni and Schistosoma japonicum.

cDNA clones encoding a 28-kDa subunit glutathione S-transferase (GST) from Schistosoma mansoni (Sm28GST) and a 26-kDa subunit GST from Schistosoma japonicum (Sj26GST) have been expressed in bacterial systems. The recombinant proteins were purified to homogeneity by batch-wash glutathione-agarose affinity chromatography and their biochemical properties investigated. Gel filtration chromatography indicated that both recombinant GSTs are homodimeric proteins. Resolution of Sm28GST and Sj26GST by chromatofocusing in the ranges pH 9-6 and pH 7-4 gave pI estimates of 7.4 and 5.0, respectively. Kinetic analyses suggested that both Sm28GST and Sj26GST operate via a sequential bisubstrate catalytic mechanism. Sm28GST and Sj26GST displayed a mosaic of mammalian Alpha-, Mu- and Pi-type substrate specificities and inhibitor sensitivities. However, multivariate analysis suggests that Sm28GST has an overall catalytic homology with mammalian Mu class GSTs, whilst the enzymatic properties of Sj26GST appear to constitute a hybridisation of Mu and Alpha class features. Both recombinant GSTs interact with a range of hydrophobic ligands including haematin and related compounds, bile acids and several anthelmintics. Sm28GST and Sj26GST possess relatively limited selenium-independent glutathione peroxidase activities, but are able to catalyse the glutathione conjugation of members of the trans,trans-alka-2,4-dienal, trans-alk-2-enal and 4-hydroxyalk-2-enal series of reactive carbonyls (known secondary products of lipid peroxidation).

Animals↗