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Biomedical subjects

R W Carlson

Publications and source records attributed to R W Carlson.

At least 127 records · Page 7Linked to original sources
PubMed1992

Acute aortic insufficiency in a patient with presumed Reiter's syndrome.

Cardiac disease is rare in patients with Reiter's syndrome. There have been 15 reported cases of aortic insufficiency in patients with Reiter's syndrome, with the aortic insufficiency developing over several years. This paper reports the case of a black HLA-B27 negative woman who presented with Reiter's syndrome and acute aortic insufficiency. An antecedent streptococcal infection is suggested as the inciting factor. To our knowledge, this is the first report of Reiter's syndrome in a black woman with acute aortic insufficiency.

Adult↗
PubMed1992

Terminal weaning from mechanical ventilation: ethical and practical considerations for patient management.

Decisions to withdraw life-sustaining therapy are being made more often as patients and healthcare providers increase their awareness of patient rights. The process of withdrawal of mechanical ventilation must be conducted in a humane fashion. An understanding of the ethical, legal and practical considerations for patient management during this type of intervention will enhance the ability of the healthcare provider to participate.

Advance Directives↗
PubMed1992

T-HELPER: automated support for community-based clinical research.

There are increasing expectations that community-based physicians who care for people with HIV infection will offer their patients opportunities to enroll in clinical trials. The information-management requirements of clinical investigation, however, make it unrealistic for most providers who do not practice in academic centers to participate in clinical research. Our T-HELPER computer system offers community-based physicians the possibility of enrolling patients in clinical trials as a component of primary care. T-HELPER facilitates data management for patients with HIV disease, and can offer patient-specific and situation-specific advice concerning new protocols for which patients may be eligible and the treatment required by those protocols in which patients currently are enrolled. We are installing T-HELPER at three county-operated AIDS clinics in the San Francisco Bay Area, and plan a comprehensive evaluation of the system and its influence on clinical research.

Clinical Trials as Topic↗
PubMed1992

Reducing the cardiotoxicity of the anthracyclines.

Most patients are not at risk for anthracycline-associated cardiotoxicity, since the cancer usually develops resistance before a dangerously high cumulative dose can be given. However, select patients may benefit from continued therapy. The physician's goal is to continue to treat these patients without risking drug-related cardiomyopathy. A simple maneuver is to switch from bolus administration to a weekly low-dose or continuous-infusion schedule. Pretreatment with ICRF-187, a new cardioprotective agent currently under investigation, may prove highly useful in the near future. Perhaps most important, the physician must be able to spot the early signs of drug-related cardiac injury. This can be accomplished with radionuclide ventriculography to determine both resting and exercise ejection fractions. Patients shown to be at high risk can then be withdrawn from the drug or further monitored with endomyocardial biopsy and right heart catheterization.

Antibiotics, Antineoplastic↗
PubMed1992

Fluid resuscitation in patients with increased vascular permeability.

Fluid therapy is a uniformly accepted, logical, and highly effective therapeutic intervention for the treatment of patients with reductions in circulating intravascular volume. This article discusses fluid resuscitation of shock associated with increased vascular permeability and addresses the use of colloids and crystalloids in these disorders.

Anaphylaxis↗
PubMed1991

Late consolidative radiation therapy in the treatment of limited-stage small cell lung cancer.

Two hundred twenty-three patients were enrolled on this randomized Phase III trial testing the value of late consolidative involved-field radiation therapy in the treatment of limited-stage small cell lung cancer (SCLC). Patients were treated with induction chemotherapy consisting of alternating cycles of procarbazine, vincristine, lomustine, and cyclophosphamide (POCC) and etoposide, doxorubicin, and methotrexate (VAM) for 6 to 9 months. Responding patients were then randomized at 6 or 9 months to chemotherapy alone or to involved-field radiation therapy. All partial and complete responders received prophylactic cranial irradiation. Of the 180 eligible and evaluable patients, 80 (44%) achieved a complete response and 39 (22%) achieved a partial response (overall rate of response, 66%). Actuarial median survival time was 11.6 months, with 16% of patients surviving 2 years and 11% surviving 5 years. Forty-eight patients were randomized to chemotherapy alone (24 patients) versus chemotherapy plus involved-field radiation therapy (24 patients). There were no significant differences in time to progression or survival between those patients receiving or not receiving involved-field radiation therapy. The thorax was the site of first relapse in 58% of patients randomized to chemotherapy alone versus 29% in patients randomized to chemotherapy plus involved-field radiation therapy (P equals 0.042). The major acute toxicity was reversible myelosuppression, and the major late toxicity was chronic central nervous system dysfunction. The authors conclude that the addition of late consolidative radiation therapy to induction chemotherapy in the treatment of limited-stage SCLC is well tolerated and improves local control, but does not improve time to progression or rates of survival.

Adult↗
PubMed1991

Compensatory growth in fibrotic lung injury.

We induced severe left-sided lung fibrosis by the unilateral endobronchial instillation of paraquat (1.0 mg/kg) into the left lungs of adult Fischer 344 male rats. Growth of the contralateral lung as well as its proliferative activity were measured 6 or 14 days later. Whereas the left lung underwent severe fibrosis and shrinkage with more than 85% reduction in lung volume, the right lung more than doubled in size. In addition, there was a significant increase in total protein content, DNA content, and DNA synthesis. We conclude that unilateral lung injury resulting in ipsilateral fibrosis and loss of parenchyma is associated with compensatory growth of the contralateral lung.

Animals↗
PubMed1991

Hemodynamic responses to gram-positive versus gram-negative sepsis in critically ill patients with and without circulatory shock.

OBJECTIVE: To examine the hemodynamic patterns of critically ill patients with septicemia to evaluate their relationship to blood bacteriology. DESIGN: Retrospective study. SETTING: Medical ICUs of a tertiary care medical center. PATIENTS: Total of 59 critically ill patients with bacteremia: 33 with Gram-positive and 26 with Gram-negative bacteremia. MEASUREMENTS: Hemodynamic variables and mixed venous oxygen saturation (SvO2) measurements associated with the highest cardiac index measured within 72 hrs of positive blood cultures. MAIN RESULTS: No significant differences in cardiac index, mean arterial pressure, systemic vascular resistance, oxygen extraction ratio, or SvO2 were observed comparing the two groups. CONCLUSION: We were unable to demonstrate clinically important differences between the hemodynamic responses to Gram-positive vs. Gram-negative sepsis.

Adult↗
PubMed1991

Distribution and phylogenetic significance of 27-hydroxy-octacosanoic acid in lipopolysaccharides from bacteria belonging to the alpha-2 subgroup of Proteobacteria.

Lipopolysaccharides (LPSs) from a number of bacteria belonging to the alpha-2 subgroup of the class Proteobacteria were screened for the presence of 27-hydroxy-octacosanoic acid (27-OH-28:0). With few exceptions, most of the bacteria contained 27-OH-28:0 in their lipid A fractions. In addition, some of the bacteria contained other n-2-hydroxylated long-chain fatty acids hitherto not reported. The distribution of 27-OH-28:0 was restricted to the alpha-2 subgroup. LPSs from members of the other subgroups (the beta and gamma subgroups), including some well-characterized enterobacterial LPSs, were devoid of 27-OH-28:0. Our results indicate that the presence of n-2-hydroxylated long-chain fatty acids in LPSs might be used as a chemophylogenetical marker.

Hydroxy Acids↗
PubMed1991

Occurrence of lipid A variants with 27-hydroxyoctacosanoic acid in lipopolysaccharides from members of the family Rhizobiaceae.

Lipopolysaccharides (LPSs) isolated from several strains of Rhizobium, Bradyrhizobium, Agrobacterium, and Azorhizobium were screened for the presence of 27-hydroxyoctacosanoic acid. The LPSs from all strains, with the exception of Azorhizobium caulinodans, contained various amounts of this long-chain hydroxy fatty acid in the lipid A fractions. Analysis of the lipid A sugars revealed three types of backbones: those containing glucosamine (as found in Rhizobium meliloti and Rhizobium fredii), those containing glucosamine and galacturonic acid (as found in Rhizobium leguminosarum bv. phaseoli, trifolii, and viciae), and those containing 2,3-diamino-2,3-dideoxyglucose either alone or in combination with glucosamine (as found in Bradyrhizobium japonicum and Bradyrhizobium sp. [Lupinus] strain DSM 30140). The distribution of 27-hydroxyoctacosanoic acid as well as analysis of lipid A backbone sugars revealed the taxonomic relatedness of various strains of the Rhizobiaceae.

Fatty Acids↗
PubMed1991

The role of physician-assistants in critical care units.

We evaluated the feasibility of utilizing physician assistants as providers of primary care in a medical ICU. After a three-month period of rigorous training, two PAs were assigned to the ICU. Their performance as well as the operation of the ICU over a two-year period was evaluated and compared to two preceding years when it was operated by house officers. There were no changes in occupancy, mortality or the rate of complications. Evidence for more careful evaluation of patients prior to admission and discharge, manifesting as slightly fewer admissions and slightly longer duration of hospitalization, was also documented. We conclude that properly trained PAs may have a role in providing health care in intensive care settings.

Critical Care↗
PubMed1990

Successful treatment of metastatic thymic carcinoma with cisplatin, vinblastine, bleomycin, and etoposide chemotherapy.

Thymic carcinomas are rare malignant neoplasms of the thymic epithelium that are distinguished from the malignant thymomas by the presence of cytologic atypia. Thymic carcinomas may metastasize outside of the thorax and are associated with a very poor prognosis. Complete responses of thymic carcinoma to chemotherapy alone have not been reported. A 21-year-old man with metastatic undifferentiated carcinoma of probable thymic origin is presented who achieved a pathologic complete response with cisplatin, vinblastine, and bleomycin chemotherapy. Additional consolidative chemotherapy with cisplatin and etoposide was administered. The patient remains disease-free 5 years after diagnosis. Cisplatin, vinblastine, and bleomycin chemotherapy appears to have significant activity against thymic carcinoma.

Adult↗
PubMed1990

Structure of a streptococcal adhesin carbohydrate receptor.

Interactions between complementary protein and carbohydrate structures on different genera of human oral bacteria have been implicated in the formation of dental plaque. The carbohydrate receptor on Streptococcus sanguis H1 (one of the primary colonizing species) that is specific for the adhesin on Capnocytophaga ochracea ATCC 33596 (a secondary colonizer) has been isolated from the streptococcal cell wall, purified, and structurally characterized. The hexasaccharide repeating unit of the polysaccharide was purified by reverse-phase, amino-bonded silica, and gel permeation high performance liquid chromatography. Earlier studies established that the repeating unit was a hexasaccharide composed of rhamnose, galactose, and glucose in the ration of 2:3:1, respectively. In the present study, determination of absolute configuration by gas chromatography of the trimethylsilyl (+)-2-butyl glycosides revealed that the rhamnose residues were of the L configuration while the hexoses were all D. 252Californium plasma desorption mass spectrometry of the native, the acetylated and the reduced and acetylated hexasaccharide determined that the molecular mass of the native hexasaccharide was 959, and that the 2 rhamnose residues were linked to each other at the nonreducing terminus of the linear molecule. Methylation analysis revealed the positions of the glycosidic linkages in the hexasaccharide and showed that a galactose residue was present at the reducing end. The structural characterization of the hexasaccharide was completed by one and two dimensional 1H and 13C NMR spectroscopy. Complete 1H and 13C assignments for each glycosyl residue were established by two-dimensional (1H,1H) correlation spectroscopy, homonuclear Hartmann-Hahn, and (13C,1H) correlation experiments. The configurations of the glycosidic linkages were inferred from the chemical shifts and coupling constants of the anomeric 1H and 13C resonances. The sequence of the glycosyl residues was determined by a heteronuclear multiple bond correlation experiment. These data show that the structure of the hexasaccharide repeating unit derived from the cell wall polysaccharide of S. sanguis H1 is: alpha-L-Rhap-(1----2)-alpha-L-Rhap-(1----3)-alpha-D-Galp- (1----3)-beta-D-Galp-(1----4)-beta-D-Glcp-(1----3)-alpha/beta-D-Gal.

Bacterial Adhesion↗
PubMed1990

High-dose cisplatin and mitomycin C in advanced non-small cell lung cancer: a phase II study of the Northern California Oncology Group.

To investigate chemotherapeutic dose intensity in advanced non-small-cell lung cancer (NSCLC), we evaluated a pharmacokinetically designed schedule of high-dose cisplatin (200 mg/m2 per 28-day cycle) plus mitomycin C. Between March 1987 and March 1989, 62 patients were registered for a phase II study of the Northern California Oncology Group (NCOG). The treatment schedule consisted of cisplatin in hypertonic saline given on a divided days 1 and 8 schedule (100 mg/m2 on each day) plus mitomycin C given at a dose of 8 mg/m2 on day 1 of each cycle. In 61 patients evaluable for response analysis, the overall response rate was 39% (24/61), with a complete response being achieved in 6% (4/61) of cases and a partial response, in 33% (20/61). The response according to reviewed histologic subtype included squamous, 53% of patients (10/19); large cell, 31% (4/13); and adenocarcinoma, 34% (10/29). The median survival for all patients was 29.3 weeks. The mean cisplatin and mitomycin C delivered dose intensities in this study were 45 mg/m2 per week (90% of the projected dose) and 1.5 mg/m2 per week (75%). The toxicity of this combination regimen in the 62 enrolled patients was significant but manageable. Leukopenia (WBC, less than 1,000/mm3) and thrombocytopenia (platelets, less than 25,000/mm3) occurred in 3% and 8% of patients treated, respectively. Dose-limiting renal toxicity and clinically significant ototoxicity developed in 8 patients each (13%), and a peripheral sensory neuropathy was observed in 17 cases (27%). Whether this type of dose-intensive therapy results in an improved therapeutic index in NSCLC is currently being evaluated in a randomized comparative trial versus standard-dose cisplatin therapy.

Adult↗