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Biomedical subjects

J L Rodriguez

Publications and source records attributed to J L Rodriguez.

At least 55 records · Page 3Linked to original sources
PubMed1998

Assessment of the relationship between timing of fixation of the fracture and secondary brain injury in patients with multiple trauma.

BACKGROUND: It has been suggested that early fixation of a fracture is deleterious to eventual neurologic outcome. We undertook this study to determine whether the timing of fracture fixation is correlated to neurologic outcome. METHODS: We retrospectively reviewed patients with severe head and orthopedic injuries requiring fracture fixation. Patients were divided into two groups: early fracture fixation (< 24 hours after injury) and late fracture fixation (> 24 hours after injury). RESULTS: One hundred twenty-three patients met entry criteria. During fracture fixation, the early group had a significant 2-, 3-, and 2-fold increase in crystalloid, blood infusion, and blood loss, respectively. There was no difference in oxygen saturation and systolic blood pressure or episodes of cranial hypertension or hypoperfusion. There was no difference in outcomes as measured by in-hospital complications, stay in the intensive care unit or hospital, mortality rates, hospital discharge or follow-up Glasgow Coma Scores, or long-term orthopedic or neurologic results. CONCLUSIONS: Patients undergoing fracture fixation with severe head injury mandate monitoring of intracranial pressure and perfusion and tailored fluid resuscitation to meet specific organ end points. Integrating end organ perfusion and pressure with meticulous fluid status during the definitive repair phase may reduce the exposure to secondary brain injury in patients undergoing early fracture fixation.

Adult↗
PubMed1998

Psychosocial factors limit outcomes after trauma.

BACKGROUND: Psychological morbidity compromises return to work after trauma. We demonstrate this relationship and present methods to identify risks for significant psychological morbidity. METHODS: Thirty-five adults were evaluated prospectively for return to functional employment after injury using demographic data, validated psychological and health measures, and the Michigan Critical Events Perception Scale. Evaluation was conducted at admission and at 1 and 5 months after injury. RESULTS: Poor return to work at 5 months was attributable to physical disability (p < 0.05) and psychological disturbance (p < 0.05) in a regression model that controlled for preinjury employment and psychopathologic factors as well as injury severity. A high score on the Impact of Events Scale administered during acute admission predicted development of acute stress disorder at 1 month (p < 0.01, odds ratio (OR) = 9.4) and posttraumatic stress disorder at 5 months (p < 0.05, OR = 6.7). Peritraumatic dissociation on the Michigan Critical Events Perception Scale was predictive for development of acute stress disorder (p < 0.05, OR = 5.8) at 1 month and posttraumatic stress disorder (p < 0.05, OR = 7.5) at 5 months. CONCLUSION: Psychological morbidity after injury compromises return to work independent of preinjury employment and psychopathologic condition, Injury Severity Score, or ambulation. A high Impact of Events Scale score or peritraumatic dissociation at admission predicts this morbidity.

Activities of Daily Living↗
PubMed1998

Lipopolysaccharide pretreatment produces macrophage endotoxin tolerance via a serum-independent pathway.

BACKGROUND: Lipopolysaccharide activation (LPSa) of macrophages is thought to occur via a CD14-dependent mechanism with a requirement for the serum factor, lipopolysaccharide binding protein. LPS-stimulated, CD14-dependent signal transduction is associated with phosphorylation of mitogen-activated protein kinase (MAPK), nuclear factor-kappaB (NF-kappaB) translocation, and secretion of tumor necrosis factor (TNF) and interleukin-1 (IL-1). Macrophage endotoxin tolerance after low-dose LPS pretreatment (LPSp) is characterized by inhibition of LPSa-stimulated TNF and augmentation of IL-1 secretion. We sought to determine the role of CD14-dependent pathways in the induction of endotoxin tolerance by comparing the effects of LPSp in the presence or absence of serum. METHODS: Murine peritoneal macrophages were exposed to a range of LPSp concentrations in the presence or absence of serum. MAPK activation and NF-kappaB were assayed 30 minutes after LPSp stimulation. TNF production and IL-1 were measured 6 hours after stimulation with 100 ng/mL LPSa, with or without 24-hour 10 ng/mL LPSp. RESULTS: In the presence of serum, 100 ng/mL LPSp activated MAPK and NF-kappaB, whereas no activation of MAPK or NF-kappaB was seen at this LPSp concentration in the absence of serum. The absence of serum during 10 ng/mL LPSp did not prevent LPSp-mediated inhibition of TNF secretion, and it significantly augmented IL-1 secretion after stimulation with 100 ng/mL LPSa in the presence of serum. CONCLUSION: Induction of the alterations in subsequent LPSa-stimulated cytokine secretion characteristic of endotoxin tolerance by LPSp occurs via a serum-independent signal transduction pathway.

Acute-Phase Proteins↗
PubMed1998

Acetazolamide treatment prevents in vitro endotoxin-stimulated tumor necrosis factor release in mouse macrophages.

We previously showed that incubation in carbon dioxide (CO2), but not air or helium (He), markedly decreased macrophage intracellular pH (pHi) and resulted in reversible inhibition of lipopolysaccharide- (LPS) stimulated tumor necrosis factor (TNF) and interleukin-1 release. We sought to determine whether carbonic anhydrase inhibition with acetazolamide would prevent CO2-mediated inhibition of LPS-stimulated TNF release. Murine peritoneal macrophages were treated with acetazolamide for 1 h under control atmosphere (95% air/5% CO2) and then switched to incubator modules containing: 1) 80% CO2/20% O2, 2) 80% He/20% O2, or 3) 100% air. Before transfer to experimental atmospheric conditions the macrophages were stimulated with 0 or 1 microg/mL of LPS (Escherichia coli 0111 B4). Supernatant TNF was measured 4 h later by bioassay. In parallel experiments LPS-stimulated cytokine mRNA was estimated using reverse transcriptase polymerase chain reaction (RT-PCR) 2 h after LPS stimulation. Viability was determined using dye uptake. Incubation in CO2 or helium had no effect on TNF production in the absence of LPS. In the absence of acetazolamide CO2 produced marked inhibition of LPS-stimulated TNF release, but this was not blocked by the presence of acetazolamide. This CO2-mediated inhibition of TNF was associated with normal levels of TNF mRNA. In acetazolamide-treated macrophages, LPS resulted in a dose-dependent inhibition of TNF release when the cells were incubated in air or helium. Maintenance of normal intracellular pH is required for TNF release, but not TNF mRNA induction by LPS. Factors that alter intracellular pH regulation may modulate LPS-stimulated cytokine production.

Acetazolamide↗
PubMed1997

In vivo endotoxin tolerance: impaired LPS-stimulated TNF release of monocytes from patients with sepsis, but not SIRS.

In vitro pretreatment of human monocytes (MO) with low-dose lipopolysaccharide (LPSp) inhibits TNF release in response to subsequent LPSa activation. Septic patients are often indistinguishable from patients with systemic inflammatory response syndrome (SIRS). We hypothesized that in vivo exposure to "septic" stimuli impairs subsequent LPSa-stimulated MO TNF production in vitro. Human peripheral MO were obtained after informed consent from controls or patients with sepsis, SIRS, or posttrauma [ACCP/SCCM definitions]. Cells were plated in vitro, incubated 24 hr, and then stimulated with 0-1000 ng/ml LPSa for 4 hr. Parallel control MO were incubated in vitro with 100 ng/ml LPSp for 24 hr and then stimulated with 1000 ng/ml LPSa for 4 hr. Supernatant TNF (mean U/ml +/- SEM) was measured by bioassay. ANOVA was used to determine statistical significance. In vitro LPSp pretreatment markedly inhibited subsequent LPSa-stimulated TNF release. In vitro LPSa-stimulated TNF release was likewise significantly inhibited with MO from septic patients compared to controls. Inhibition was more profound in septic patients with shock (not shown). No impaired TNF release was seen with MO from SIRS or trauma patients. In conclusion, in vivo preexposure to inflammatory stimuli in septic patients alters monocyte regulation in a manner similar to in vitro endotoxin tolerance. Provocative in vitro monocyte LPS stimulation may distinguish patients with sepsis and SIRS.

Adult↗
PubMed1997

Protein kinase C regulates macrophage tumor necrosis factor secretion: direct protein kinase C activation restores tumor necrosis factor production in endotoxin tolerance.

BACKGROUND: Macrophages pretreated in vitro with endotoxin (LPSp) secrete less tumor necrosis factor (TNF) in response to a second LPS activating (LPSa) stimulus. Protein kinase C (PKC) is required for TNF secretion in a macrophage stimulated with LPSa. In these experiments we examined the role of PKC in TNF signal transduction in naive and tolerant macrophages. METHODS: Murine macrophages were cultured +/- LPSp for 24 hours. Cultures were washed and treated for 1 hour with PKC inhibitors or phorbol myristate acetate (PMA), a direct PKC activator. Cells were then stimulated with a range of LPSa for 6 hours, and TNF was determined by bioassay. RESULTS: LPSa-stimulated TNF secretion by nontolerant macrophages was inhibited by LPSp in the absence of PMA. PKC inhibitors decreased TNF by naive macrophages and exaggerated inhibition in tolerant cells. Depletion of PKC by 24 hours of PMA decreased TNF production by both naive and tolerant macrophages. PKC activation with PMA 1 hour before LPSa augmented TNF secretion in naive cells and reversed TNF inhibition of tolerant cells. CONCLUSIONS: Direct PKC activation with PMA restored TNF secretion in LPS-tolerant macrophages. Endotoxin tolerance may alter the LPSa signal transduction pathway between the LPS receptor and PKC activation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1997

Mechanism of decreased in vitro murine macrophage cytokine release after exposure to carbon dioxide: relevance to laparoscopic surgery.

OBJECTIVE: The objective of this study was to determine the effect of carbon dioxide (CO2) on the function of peritoneal macrophages. SUMMARY BACKGROUND DATA: Laparoscopic surgery is associated with minimal pain, fever, and low levels of inflammatory cytokines. To understand the mechanisms involved, the authors investigated the effect of different gases on murine peritoneal macrophage intracellular pH and correlated these alterations with alterations in LPS-stimulated inflammatory cytokine release. METHODS: Peritoneal macrophages were incubated for 2 hours in air, helium, or CO2, and the effect of the test gas on immediate or next day lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF) and interleukin-1 release compared. Cytosolic pH of macrophages exposed to test gases was measured using single-cell fluorescent imaging. The in vivo effects of test gases were determined in anesthetized rats during abdominal insufflation. RESULTS: Macrophages incubated in CO2 produced significantly less TNF and interleukin-1 in response to LPS compared to incubation in air or helium. Cytokine production returned to normal 24 hours later. Exposure to CO2, but not air or helium, caused a marked cytosolic acidification. Pharmacologic induction of intracellular acidification to similar levels reproduced the inhibitory effect. In vitro studies showed that CO2 insufflation lowered tissue pH and peritoneal macrophage LPS-stimulated TNF production. CONCLUSIONS: The authors propose that cellular acidification induced by peritoneal CO2 insufflation contributes to blunting of the local inflammatory response during laparoscopic surgery.

Animals↗
PubMed1997

Posttrauma thromboembolism prophylaxis.

PURPOSE: The need to study methods of thromboembolism prophylaxis in high-risk trauma patients is well established. The purpose of this study was to evaluate the feasibility of a proposed study design, including current methods of prophylaxis, performance of a risk assessment profile scale, and the use of serial color-flow duplex studies in detecting deep venous thrombosis (DVT). METHODS: Patients were enrolled into the study, stratified as to their ability to receive anticoagulation and randomized to low-dose unfractionated heparin, low molecular weight heparin, pneumatic compression devices, or foot pumps with or without vena caval filters. Serial ultrasound scans were performed at designated intervals for 4 weeks. Pulmonary angiograms were obtained for clinical signs or symptoms of pulmonary embolism. RESULTS: Fifty-three patients, 32 male and 21 female patients with a mean age of 44 years, completed the study. The incidence of DVT was 43% (23 of 53 patients) and significantly higher in older patients. There were no pulmonary embolisms. Color-flow duplex proved to be a sensitive method for detecting both proximal and distal thrombi. The risk assessment profile for thromboembolism (RAPT) scale identified a group of patients with a high incidence of DVT. However, the occurrence of DVT was not correlated with the magnitude of the RAPT score. CONCLUSION: The ability to identify a population with a high incidence of thromboembolism by using the RAPT score to detect asymptomatic DVT, and the suggested advantage of low molecular weight heparin, all support the need for an appropriately powered randomized clinical trial.

Adult↗
PubMed1997

Consequences of high-dose steroid therapy for acute spinal cord injury.

OBJECTIVE: High-dose Solu-Medrol (Upjohn, Kalamazoo, Mich) therapy has become standard care in the management of acute spinal cord injury (ASCI). This study attempts to define the adverse effects that Solu-Medrol therapy has on these patients. DESIGN: Retrospective review with historical control. MATERIALS AND METHODS: From May 1990 to April 1994, all patients with ASCI admitted within 8 hours of injury received high-dose Solu-Medrol per the National Acute Spinal Injury Study (NASCIS-2) protocol. Their demographic and outcome parameters were compared with those of a group admitted from March 1986 to December 1993 with an associated ASCI who received no steroid therapy. MEASUREMENTS AND MAIN RESULTS: Steroid therapy was associated with a 2.6-fold increase in the incidence of pneumonia and an increase in ventilated and intensive care days. However, it was associated with a decrease in duration of rehabilitation and had no significant impact on other outcome parameters, including mortality. CONCLUSIONS: Although the NASCIS-2 protocol may promote early infectious complications, it has no adverse impact on long-term outcome in patients with ASCIs.

Accidents, Traffic↗
PubMed1997

Physician resource utilization after geriatric trauma.

OBJECTIVE: As health care resources become increasingly strained, the value of physician consultation has come under heightened scrutiny. This report reviews the value of early consultation by the physical medicine and rehabilitation (PMR) service to an integrated trauma service for geriatric patients with multiple trauma. METHODS: We retrospectively reviewed the records of 110 geriatric trauma patients (age > 60 years) with an Injury Severity Score > or = 15 to evaluate the effects of PMR consultation. Patients in group 1 were admitted to a general surgical service, and those in group 2 were admitted to a multidisciplinary trauma service. Demographic and physiologic factors, as well as short-term and long-term outcomes, were evaluated, and a subgroup analysis was performed to compare early (< or =3 days) versus late (>3 days) consultation by PMR. RESULTS: Although there were significant differences in Glasgow Coma Scale score and length of stay, no differences were found within groups in other demographic, physiologic, or outcome data. Focused review of PMR intervention based on early versus late consultation revealed no significant difference between the two groups. Furthermore, an after-discharge phone survey revealed no significant group differences in dependence on a care provider or nursing home placement, readmission to hospital, employment status, or current functional activity status. CONCLUSIONS: Long-term patient functional outcome and the in-house rehabilitation process are not affected by integration of PMR into a multidisciplinary trauma team or early PMR consultation.

Aged↗
PubMed1997

Usefulness of 99Tcm-tetrofosmin scintimammography in palpable breast tumours.

The aim of this exploratory study was to assess the potential of discriminating malignant from non-malignant lesions using 99Tcm-tetrofosmin scintimammography in the detection of palpable breast tumours. Nine patients with palpable masses were studied; seven had malignant lesions and two had non-malignant lesions. All diagnoses were established by fine-needle aspiration (FNA) biopsy cytology. Each patient received 925 MBq (25 mCi) 99Tcm-tetrosfosmin intravenously. Planar prone views were acquired in the right lateral, left lateral and anterior positions, and the axillary regions were included in the field of view. Scintimammography showed focally increased tracer uptake in seven patients with a positive FNA result. The two patients with a negative FNA result showed no increased uptake. We suggest that 99Tcm-tetrosfosmin shows promise as a radiopharmaceutical in the detection and discrimination of the nature of palpable breast tumours. Larger studies are required to confirm these findings.

Aged↗
PubMed1997

Renal 99Tc(m)-DMSA SPET and planar imaging: are they really the same?

Previous studies have suggested that more defects are detected on SPET than on planar DMSA images. The aim of this study was to evaluate differences between planar and SPET imaging. Sixty-four kidneys from pyelonephritic patients were studied using both techniques. An automated algorithm for reorientation and centring of the SPET images was used to minimize inter-observer variability. Reduced uptake and contour defects showed different localization on planar and SPET imaging. Coincidence of defects on both types of image was low. We also noted a dependence on defect frequency content for detectability. Image contrast played a noticeable role in the detection of defects. Differences in contrast between SPET and planar images may be responsible for the variable success in the detection of defects. Contour defects are seen more frequently on tomographic slices, whereas reduced uptake defects are seen more frequently on planar images. A difference is also noted between the cortical and calyceal zones for differently contrasted lesions. SPET and planar DMSA images can potentially provide a different diagnosis of renal lesions.

Adult↗
PubMed1997

Polymerase chain reaction and restriction endonuclease digestion for selected members of the "Mycoplasma mycoides cluster" and Mycoplasma putrefaciens.

A specific diagnostic method using the polymerase chain reaction, together with restriction endonuclease digestion patterns, was developed for members of the "Mycoplasma mycoides cluster" that normally occur in the United States (i.e., Mycoplasma mycoides subsp. mycoides Large Colony and Mycoplasma capricolum subsp. capricolum in addition to "cluster" mycoplasma, bovine serogroup 7, and Mycoplasma putrefaciens. The digestion of "cluster" polymerase chain reaction DNA (1,225 bp) amplification products with restriction enzymes AseI and SspI gave mycoplasma species-specific patterns for all strains of M. mycoides subsp. mycoides Large Colony, M. capricolum subsp. capricolum, and bovine group 7 tested. Moreover, we found a nonspecific amplification product for M. putrefaciens that occurred with the oligonucleotide primers used for the "M. mycoides cluster" reaction. However, the restriction endonuclease digestion patterns observed with the restriction enzymes AluI, AseI, and SspI for M. putrefaciens were different than the digestion patterns obtained for the other "cluster" mycoplasmas. This report confirms the usefulness of polymerase chain reaction DNA amplification allied with restriction enzyme digestion profile analysis for the rapid and specific identification of mycoplasmas belonging to the "M. mycoides cluster" and M. putrefaciens.

Animals↗
PubMed1997

Mastalgia. Tailoring treatment to type of breast pain.

Breast pain is a common, often distressing problem among women. After significant disease is ruled out, most patients respond to simple reassurance. Others, however, require treatment because symptoms interfere with their lifestyle. The authors offer practical suggestions for tailoring treatment for these patients according to type of pain--cyclical mastalgia, non-cyclical mastalgia, or chest wall pain.

Breast↗
PubMed1997

Bactericidal effect of enterocin 4 on Listeria monocytogenes in a model dairy system.

Enterococcus faecalis INIA 4 produced the bacteriocin enterocin 4 during growth in raw ewe's milk at 30 degrees C. Enterocin activity reached 2,200 to 3,600 AU/ml after 8 h, with a 1 to 8% (vol/vol) level of inoculum from an 18-h culture. An enterocin activity of 500 AU/ml significantly decreased counts of Listeria monocytogenes Ohio when incubated for 6 h in a model system consisting of filtrates from cultures of E. faecalis INIA 4 in raw ewe's milk, at pH 6.0 and 30 degrees C. However, an enterocin activity of 2,400 AU/ml was needed in the same conditions to significantly decrease counts of L. monocytogenes Scott A. All 22 wild L. monocytogenes strains isolated from ewe's milk and tested were inhibited by a filtrate containing 400 AU/ml of enterocin 4. Incubation in the filtrate for 6 h significantly lowered counts of 16 L. monocytogenes strains, and incubation for 24 h, counts of 21 strains.

Animals↗
PubMed1997

Early versus late tracheostomy in the trauma patient.

The use of early tracheostomy in the multiply injured trauma patient has many advantages both in terms of patient management and reduction of morbidity associated with prolonged translaryngeal intubation. Tracheostomy (percutaneous or open technique) has been associated with very low risk of mortality and comparable morbidity to prolonged endotracheal intubation. There exist improved clinical criteria for predicting which patients will require prolonged mechanical ventilation in the trauma and critical care setting. A delay in converting translaryngeal intubation to tracheostomy had been associated with longer ICU stays; conversely, early tracheostomy has been associated with a reduction in ICU stays, incidence of hospital-acquired pneumonias, mechanically ventilated days, and length of hospital stay. Thus, the benefits of early tracheostomy are improved care for patients in the trauma or critical care setting and reduced hospital and patient costs.

Humans↗