Search PubMed⌕ Search

Biomedical subjects

J W Smith

Publications and source records attributed to J W Smith.

At least 91 records · Page 5Linked to original sources
PubMed1998

Peripheral T lymphocytes from women with breast cancer exhibit abnormal protein expression of several signaling molecules.

We examined signaling molecules of peripheral blood T lymphocytes obtained from women with breast cancer. In 6 of 14 patients, T lymphocytes displayed an impaired ability to translocate NFêB p65 (Rel-A) following activation by anti-CD3 and IL-2. This observation was made despite normal cytoplasmic levels of the Rel-A protein. We also detected abnormally low levels of the signaling molecules T-cell receptor (TCR)-zeta, ZAP-70 and p56lck in 4 of 14 breast cancer patients, i.e., defects in T-cell signaling molecules. T lymphocytes from 6 of the 14 patients also exhibited an increased expression of the dual specificity phosphatase, map kinase phosphatase-1 (MKP-1). MKP-1 inactivates MAP kinase and therefore may interfere with the activation of c-jun and c-fos. Abnormalities of I or more signaling molecules were found in 9 of 14 patients; however, only 3 patients had T cells that exhibited all 5 defects. Our data have implications for the detection of potentially dysfunctional T cells in patients with cancer. For example, the analysis of only 1 signaling molecule may allow patients with significant defects in T-cell signaling to go unnoticed. Finally, despite impaired Rel-A translocation, T cells were capable of transcribing IL-2. Impairments in the translocation of Rel-B and c-Rel further suggest that the NFKB family members Rel-A, Rel-B and c-Rel are not required for the transcription of IL-2 in the peripheral T lymphocytes of patients with breast cancer.

Adult↗
PubMed1998

Pneumothorax secondary to Dirofilaria immitis infection in two cats.

Dirofilariasis was diagnosed in 2 cats with spontaneous pneumothorax. One cat had a 3-week history of a cough, and the other had an 11-month history of vomiting and tachypnea. Pneumothorax was managed in cats by thoracocentesis and supportive care. Diagnosis of dirofilariasis was made on the basis of heartworm antigen and antibody test results and radiographic findings. Clinical signs of heartworm infection improved after treatment with corticosteroids. Cats had good extended outcomes. Heartworm disease should be one of the differential diagnoses considered in cats with spontaneous pneumothorax.

Animals↗
PubMed1998

Pneumocystis carinii mutations associated with sulfa and sulfone prophylaxis failures in AIDS patients.

BACKGROUND: Failures of prophylaxis against Pneumocystis carinii pneumonia (PCP) in AIDS patients do occur, but no evidence for drug resistance has yet been presented. OBJECTIVE: To determine whether mutations in the sulfa and sulfone drug target are associated with failure of prophylaxis using a sulfa-containing agent. METHODS: Portions of the gene for P. carinii dihydropteroate synthase (DHPS), the sulfa and sulfone target, from 27 patients (20 of whom had AIDS) diagnosed with PCP between 1976 and 1997 were amplified using polymerase chain reaction and sequenced. Seven of the 27 patients (all of whom had AIDS) were receiving sulfa or sulfone drugs as prophylaxis for PCP. RESULTS: Mutations were found at only two amino-acid positions and were significantly more common in patients who received sulfa/sulfone prophylaxis. Mutations were observed in five (71%) out of seven isolates from AIDS patients receiving sulfa/sulfone as prophylaxis compared with only two (15%) out of 13 specimens from AIDS patients who did not (P = 0.022). No mutations were seen in isolates from seven non-HIV-infected patients, none of whom were on prophylaxis. Mutations were only observed in specimens obtained in 1995-1997. CONCLUSIONS: Mutations in two amino-acid positions were significantly more common in AIDS patients with PCP who failed sulfa/sulfone prophylaxis. These amino acids appeared to be directly involved in both substrate and sulfa binding, based on homology to the Escherichia coli DHPS crystal structure. Thus, the results were consistent with the possibility that mutations in the P. carinii DHPS are responsible for some of the failures of sulfa/sulfone prophylaxis in AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: diagnosis and management.

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is a clinical syndrome defined by the presence of thrombocytopenia and microangiopathic hemolytic anemia without a clinically apparent etiology. Patients may also have multiple other symptoms and signs including neurologic and renal abnormalities and fever. In the era prior to effective therapy with plasma exchange, most patients developed multisystem abnormalities and the syndrome was more easily recognized. Now, since there is urgency to begin treatment, sufficient diagnostic criteria for TTP-HUS are only thrombocytopenia and microangiopathic hemolytic anemia without a clinically apparent cause; patients may have no neurologic symptoms, renal abnormalities, or fever. This has lead to an apparent increased incidence because of both the increased importance of early recognition and the decreased specificity of the diagnostic criteria. Effective treatment has also revealed new aspects of the clinical course of TTP-HUS following the initial response to plasma exchange treatment: prompt exacerbations, which are common when plasma exchange is diminished in frequency or discontinued, and later relapses, which may occur many years after the initial episode. This review describes the evolution of the syndrome of TTP-HUS in the current era of effective treatment, and describes the management and clinical outcomes among patients treated by the Oklahoma Blood Institute.

Hemolytic-Uremic Syndrome↗
PubMed1998

Granulocyte colony-stimulating factor use is associated with decreased bacteremia and increased survival in neutropenic HIV-infected patients.

BACKGROUND: Neutropenia occurs in up to 17% of human immunodeficiency virus (HIV)-infected individuals. Although granulocyte colony-stimulating factor (G-CSF) can reverse HIV-related neutropenia, it is not established that this therapy can reduce bacterial infections and affect survival. METHODS: A retrospective cohort study of 152 neutropenic, HIV-infected patients was performed to determine the therapeutic utility of G-CSF. Medical records of 71 patients who received G-CSF and 81 patients who never received G-CSF, during the years of 1991 to 1994 at Parkland Memorial Hospital, were reviewed for the incidence of bacteremia, G-CSF use, antiretroviral therapy (AR), Pneumocystis carinii pneumonia prophylaxis (PCPP), and opportunistic infections (OI). RESULTS: The two patient groups had similar baseline characteristics including CD4 count (37 cells/mm3 versus 40 cells/ mm3, P=0.7). Univariate analysis revealed and trend toward decreased rates of all bacteremias in the G-CSF-treated group compared with the controls (0.54 bacteremias/100 patient months versus 2.2 bacteremias/100 patient months, P=0.064) and a marked decrease in the rates of gram-negative rod bacteremias in the G-CSF-treated group compared with the untreated group (0.09 gram-negative rod bacteremias/100 patient months versus 1.7 gram-negative rod bacteremias/100 patient months, P=0.002). In a multivariate analysis, significant decreased risk for bacteremia was found with G-CSF use (odds ratio [OR]=0.15, P=0.02). Survival was longer in patients treated with G-CSF than in the untreated group (median: 397 days versus 165 days). Multivariate analysis using Cox Proportional Hazards Model showed decreased risk of death in patients treated with G-CSF, ARs, PCPP. CONCLUSIONS: We conclude that G-CSF use is associated with decreased bacteremias and is associated with prolonged survival in neutropenic, HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

ABH antigens on human platelets: expression on the glycosyl phosphatidylinositol-anchored protein CD109.

Platelets express alloantigens that are platelet specific (eg, the HPA antigens) and alloantigens that are shared with other blood cells (eg, the ABH antigens). The blood group A and B determinants are expressed on glycolipids and on some intrinsic platelet membrane glycoproteins. This report characterizes multiple platelet proteins reacting with blood group antibodies in serum samples from mothers of children born with neonatal alloimmune thrombocytopenia. ABH antigens on additional platelet proteins are identified, including the glycosyl phosphatidylinositol-anchored protein CD109. The proteins that carry ABH antigens were identified by using monoclonal antibodies to glycoproteins Ib, IIb/IIIa, Ia/IIa, CD31, and CD109 and immunoprecipitation/immunoblotting techniques with monoclonal antibodies to A and B antigens. The maternal serum samples and anti-A and anti-B monoclonal antibodies immunoprecipitated identical radiolabeled platelet proteins including proteins at 220 and 175 kd and proteins with mobilities corresponding to glycoproteins Ib, IIb/IIIa, IV, and V. Treatment of platelets with phosphatidylinositol-specific phospholipase C released into the supernatant a 175-kd protein that expressed the blood group determinants. This protein comigrated with the glycosyl phosphatidylinositol-anchored protein CD109. When platelet proteins were purified by immunoprecipitation with monoclonal antibodies and then tested by immunoblotting, anti-A reacted with the glycosyl phosphatidylinositol-anchored protein CD109 and to glycoproteins Ib, IIb, IIa, IIIa, and CD31 (PECAM). These results indicate that structures for modification by glycosyltransferases exist on platelet CD109, which also expresses the Gov alloantigen system. This study indicates that certain platelet proteins express both platelet-specific and blood group antigens that may contribute to platelet transfusion refractoriness and to neonatal alloimmune thrombocytopenia.

Animals↗
PubMed1998

Primary sarcomas of the mediastinum: results of therapy.

UNLABELLED: Primary sarcomas of the mediastinum are rare, and data concerning treatment and results of therapy are sparse. OBJECTIVE: To assess presentation, management, prognostic factors, and survival in mediastinal sarcomas. METHODS: We reviewed our experience with 47 patients with the diagnosis of primary sarcoma of the mediastinum. Data were collected from a computerized institutional database and medical records. Survival was analyzed by Kaplan-Meier method and comparisons of survival by log rank test. RESULTS: The median age of 47 patients with mediastinal sarcoma was 39 years (range 2.5 to 69 years), with a male/female ratio of 1.6. The most common complaints were chest/shoulder pain (38%) and dyspnea (23%). The most common tumor types were malignant peripheral nerve tumor (26%), spindle cell sarcoma (15%), leiomyosarcoma (9%), and liposarcoma (9%). Operation was the primary treatment modality in 72% of cases (n = 34); 22 sarcomas (47%) were completely resected. The overall 5-year survival was 32%. High-grade lesions had a significantly decreased survival (5-year survival = 27%) compared with low-grade tumors (5-year survival = 66%) (p = 0.05). The overwhelming factor determining survival was the ability to completely resect the tumors (5-year survival 49% for complete resection; 3-year survival 18% for incomplete or no resection) (p = 0.0016). Despite complete resection, local recurrence occurred in 64% of cases. CONCLUSION: Because the overall survival for patients with mediastinal sarcomas is 32% and the local recurrence is 64% for tumors completely resected, aggressive adjuvant therapy should continue to be systematically explored.

Adolescent↗
PubMed1998

Evaluation of the protective value of hospital gowns against blood strike-through and methicillin-resistant Staphylococcus aureus penetration.

BACKGROUND: Hospital gowns protect patients and health care workers from exposure to blood and other infectious materials. Previous studies have shown that certain gowns do allow blood strike-through. Because of worldwide increases in the incidence of Staphylococcus aureus infections, especially with methicillin-resistant strains, there is now increased concern regarding bacterial transmission through gowns. METHODS: This study evaluated six gown types used in hospitals (one disposable cover or isolation gown, three disposable operating room gowns, and new and washed reusable operating room gowns). Gowns were evaluated for dry spore and S. aureus filtration efficiencies and were subjected to 20 time-pressure combinations with methicillin-resistant S. aureus-spiked blood (10(4)/ml) to evaluate blood strike-through and passage of methicillin-resistant S. aureus. RESULTS: Blood strike-through was lowest with disposable operating room gowns 1 and 2 (polypropylene). Disposable operating room gown 3 (polyester-wood pulp) showed the greatest strike-through and overall passage of methicillin-resistant S. aureus. Operating room gowns 1 and 2 showed minimal bacterial passage, whereas the disposable cover (polypropylene) only allowed passage at pressures greater than 1 psi. Bacterial filtration efficiency testing showed operating room gowns 1 and 2 to be the most protective; operating room gown 3 and both reusable (cotton) gowns were the least protective. Dry spore passage was greatest for reusable gowns. CONCLUSION: Different hospital gowns offer varying degrees of protection against fluid strike-through or bacterial passage. Gowns therefore should be chosen according to the task performed and conditions encountered.

Analysis of Variance↗
PubMed1998

Alphav integrins mediate adhesion and migration of breast carcinoma cell lines.

Integrins with the alphav subunit are involved in cell adhesion and cellular signaling. Some alphav integrins have been associated with tumor progression and dissemination. The objective of this study was to assess the contribution of alphav integrins to the adhesive and migratory behavior of cells derived from breast carcinoma (BCA). The expression and function of alphav integrins was characterized in three BCA cell lines which exhibit different metastatic potentials. These include MCF-7 cells which metastasize inefficiently, MDA-MB-231 cells, which have a moderate metastatic potential, and MDA-MB-435 cells, which metastasize extensively. Each cell type displays a different repertoire of alphav integrins on the cell surface. The complement of alphav integrins on each cell type influences their ability to adhere and migrate. The most striking difference among these cell lines was the expression of the alphavbeta3 integrin. The highly metastatic MDA-MB-435 cells express substantial levels of this receptor, whereas MDA-MB-231 and MCF-7 cells do not. The MDA-MB-435 cells showed a greater ability to adhere and to migrate and this functional difference can largely be attributed to the expression of alphavbeta3 integrin. This characterization is a first step toward determining the role of alphav integrins in animal models of BCA metastasis, and lends support to the hypothesis that the alphavbeta3 integrin can be a contributing factor in metastatic disease.

Antigens, CD↗
PubMed1998

Frequency of immediate adverse effects associated with apheresis donation.

BACKGROUND: Apheresis donation is considered safe, but the incidence of adverse effects has not been determined in a large multicenter series of donations with modern instruments. STUDY DESIGN AND METHODS: The Hemapheresis Committee of the American Association of Blood Banks devised a uniform questionnaire that asked about 32 specific adverse effects. Transient paresthesia and mild vasovagal events were excluded. A survey was conducted in 1995; 17 centers returned 19,611 responses concerning 250 to 2,000 consecutive apheresis donations per center. RESULTS: Six hundred adverse effects were reported in 428 donations (2.18% of donations). Pain or hematoma at a venipuncture site was the most common response (1.15% of donations); only 203 donations had other (nonvenipuncture) adverse effects (1.04%). Total and nonvenipuncture rates were, respectively, 4.84 and 2.92 percent for 2,295 first donations and 1.78 and 0.77 percent for 17,303 repeat donations (p < 0.001). Rates of nonvenipuncture symptoms in first and repeat donations were, respectively, citrate-induced nausea and/or vomiting, 0.87 and 0.27 percent; tetany, 0.09 and 0.04 percent; pallor and/or diaphoresis, 1.87 and 0.32 percent; vasovagal nausea and/or vomiting, 0.87 and 0.13 percent; syncope and/or seizure, 0.39 and 0.04 percent; and chills and/or rigors, 0.31 and 0.01 percent. The overall rate of donor unconsciousness was 0.08 percent. Hemolysis was reported twice. Clotting or leakage occurred in 0.08 percent of donations, and inability to return blood occurred in 0.16 percent. No life-threatening adverse effects were reported. Procedure-specific nonvenipuncture rates were 1.05 percent of 17,584 platelet donations, 0.67 percent of 594 white cell donations, and 0.37 percent of 1,354 plasma donations. Center-specific rates varied from 0.32 to 6.81 percent of donations for total adverse effects and from 0.11 to 2.92 percent of donations for nonvenipuncture events. CONCLUSION: Apheresis donation is a safe undertaking, suitable for voluntary blood donors, with a very low risk of serious adverse effects. The risk of unconsciousness is lower than that found in many studies of whole-blood donation.

Blood Component Removal↗
PubMed1998

Demographic characteristics, unreported risk behaviors, and the prevalence and incidence of viral infections: a comparison of apheresis and whole-blood donors. The Retrovirus Epidemiology Donor Study.

BACKGROUND: The demographics, deferrable risk behaviors, and the prevalence and incidence of viral infections of apheresis (PH) and whole-blood (WB) donors were compared, to characterize these two populations and to evaluate the relative safety of PH and WB donors in terms of transfusion-transmitted viral infections. STUDY DESIGN AND METHODS: A comparison was made of 36,119 PH donors (> or = 1 PH donation) and 1.38 million WB donors (> or = 1 WB donation) in terms of demographics and the prevalence (/100,000 donors) and incidence (/100,000 person-years) of viral infections, by using data collected at five United States blood collection centers between 1991 and 1994. Deferrable risk behaviors were defined as those risk behaviors that would have resulted in donor deferral, had they been reported. The prevalence of deferrable risk behaviors was estimated by using data collected through an anonymous mail survey. RESULTS: PH donors were older and more likely than repeat (2+ donations) WB donors to be female, white, and United States-born and to have a higher degree of education (p < or = 0.001). The prevalence of any viral infection was 50 percent higher in WB donors than in PH donors (p = 0.04), whereas the incidence of HIV, human T-lymphotropic virus, and hepatitis B surface antigen was nonsignificantly higher in WB donors. The prevalence of deferrable risk behaviors did not differ in the two groups. CONCLUSION: Further studies will be needed to evaluate whether the difference in the prevalence of viral infections observed in this study can be explained by demographic characteristics and patterns of donation frequency.

Blood Component Removal↗
PubMed1998

Sequence polymorphisms in the Pneumocystis carinii cytochrome b gene and their association with atovaquone prophylaxis failure.

Atovaquone (Mepron, 566c80) is an effective agent against Pneumocystis carinii, which probably acts by binding to cytochrome b and inhibiting electron transport. To assess the possibility that atovaquone resistance might be developing, the genes for the cytochrome b from P. carinii sp. f. carinii and P. carinii sp. f. hominis were partially sequenced. Eight of 10 patient isolates had cytochrome b genes with the same amino acid sequence. The P. carinii cytochrome b genes from 2 of 4 patients who had atovaquone prophylaxis failure contained mutations resulting in amino acid changes in one of the ubiquinone (coenzyme Q) binding sites (Qo). These mutations are homologous to mutations in other microorganisms that confer resistance to similar inhibitors. Variations in the sequence of the P. carinii cytochrome b gene suggest but do not prove the development of drug resistance.

Amino Acid Sequence↗
PubMed1998

Anaesthetic management of a woman who became paraplegic at 22 weeks' gestation after a spontaneous spinal cord haemorrhage secondary to a presumed arteriovenous malformation.

A 19-yr-old woman developed a paraplegia with a T10 sensory level at 22 weeks' gestation. The spinal injury was caused by spontaneous bleed of a presumed arteriovenous malformation in the spinal cord. She presented for Caesarean section at term because of the breech position of her fetus. The successful use of a combined spinal epidural-regional anaesthetic is described and the risks of general and regional anaesthesia are discussed.

Adult↗
PubMed1998

Complete spontaneous regression of pulmonary metastatic melanoma.

BACKGROUND: Complete spontaneous regression of melanoma metastatic to the lungs is a rare event. OBJECTIVE: To report a case of biopsy-proven melanoma metastatic to the lung with complete spontaneous regression. METHODS: Multidisciplinary case report. RESULTS: A 35-year-old white female was diagnosed with metastatic melanoma to the lung. A pleural biopsy confirmed the diagnosis. Partial spontaneous regression was noted by a staging computed tomography scan prior to enrollment in an investigational protocol. Complete spontaneous regression occurred over 5 months without any form of conventional or alternative therapy, and the patient remains disease-free 3 years after diagnosis. CONCLUSIONS: Our case represents the seventh case of complete spontaneous regression of melanoma metastatic to the lung, and the only case with histologic confirmation of both the primary and pulmonary metastatic lesions. The patient was pregnant twice between the time of her initial diagnosis of primary melanoma and pulmonary metastatic disease.

Adult↗
PubMed1998

Efficacy of sulfamethoxypyridazine in a murine model of Pneumocystis carinii pneumonia.

Sulfamethoxazole is the component of co-trimoxazole responsible for its efficacy against Pneumocystis carinii pneumonia, but this drug is associated with frequent adverse effects. Sulfamethoxypyridazine is significantly more effective than sulfamethoxazole against a murine model of P. carinii and might be a candidate for testing in infected patients.

Animals↗
PubMed1998

Antibody to Pneumocystis carinii protects rats and mice from developing pneumonia.

Well-proven mouse and rat models were used to show that polyclonal antisera to Pneumocystis carinii protect against P. carinii pneumonia. Antibodies were obtained from animals that were allowed to recover from severe P. carinii pneumonia after immunosuppression had been stopped and which then were given a booster injection of P. carinii from the same animal species. Mice immunosuppressed with corticosteroids or antibodies to L3T4+ lymphocytes (which are comparable to CD4 cells of humans) and transtracheally inoculated with mouse P. carinii did not develop P. carinii pneumonia if they were passively immunized with antiserum, while mice immunosuppressed and inoculated by identical procedures but not given antibodies developed severe infections. Rats immunosuppressed with corticosteroids and inoculated with rat P. carinii had less severe infections if they were given rat anti-P. carinii antisera. The polyclonal antisera developed in mice provided greater protection for the mice than the polyclonal rat antisera did for the rats; however, the potencies and compositions of the antisera were not quantitated and probably differed. Since both rats and mice can be protected from P. carinii infections with polyclonal antisera, it may be possible to develop vaccines that will elicit protective antibodies in humans.

Animals↗