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Biomedical subjects

F Lee

Publications and source records attributed to F Lee.

At least 163 records · Page 9Linked to original sources
PubMed1992

The role of digital rectal examination, transrectal ultrasound, and prostate specific antigen for the detection of confined and clinically relevant prostate cancer.

In a study population, can digital rectal examination (DRE), transrectal ultrasound (TRUS), and prostate specific antigen (PSA) (monoclonal) effectively detect the majority of clinically relevant cancer? If this is possible, the remaining patients could then be considered for chemopreventive protocols. The American Cancer Society/National Prostate Cancer Detection Project (ACS/NPCDP) had a cancer detection rate of 2.4% for its initial year utilizing PSA, DRE and TRUS. TRUS and PSA detected 73% more cancer than DRE alone. TRUS detected a greater percentage of cancers than DRE (85% vs. 64%). PSA was > or = 4 ng/ml for 66% of prostate cancer patients; 11% of cancer patients had PSA < 2 ng/ml. PSA decision levels based on gland volume detected a subgroup at the 95th percentile that had a nine-fold increased risk for cancer. In a separate study differentiating benign prostatic hypertrophy (BPH) and cancer, we found 0.12 +/- 0.13 ng/ml/gm for serum PSA (sPSA)/gm BPH. This study proved that predicted PSA (pPSA) = gland volume x 0.12; this equation also functioned at the 95th percentile for any individual patient. Individual patient assessment: 1. Entry level PSA = 2 ng/ml. 2. Those patients with PSA > 2 ng/ml have TRUS determination of gland volume (performed by technician). 3. pPSA = gland volume x 0.12. If sPSA > pPSA then: 4. (sPSA-pPSA)/2 = predicted volume (cc) of cancer; 5. 3 square root of volume of cancer = mean diameter (cm) of cancer. Thus, these results should detect the majority of clinically relevant cancer (> 0.5 cc). PSA combined with TRUS and DRE can identify high risk groups for cancer.

Humans↗
PubMed1992

Internalization of CD4 molecules in human T-cells demonstrated by immuno-electron microscopy.

Internalization of CD4 molecules on human CD4-enriched T-cells was demonstrated by immunocytochemical electron microscopy. CD4+ T-cell subclones were obtained from normal human peripheral blood, followed by one-way MLC screening and co-culturing with IL-2. Fixed and non-fixed T-cell samples were indirectly immunolabeled with mouse anti-human CD4 monoclonal antibody and goat anti-mouse IgG conjugated with peroxidase. Unfixed T-cells were immunolabeled at 4 degrees C and then re-incubated for 5-45 min at 37 degrees C. The selected CD4+ T-cell subclones showed strong CD4 binding on the cell surface after IL-2 incubation. However, fresh T-cells, monocytes, bone marrow cells and CD8+ T-cells all stained negative for CD4. The distribution of CD4 molecules on the fixed cell surface showed a homogeneous pattern. Capping and internalization of CD4-antibody-peroxidase complexes from the cell surfaces were observed follow a pathway of receptor-mediated endocytosis in unfixed T cells. Endocytotic vesicles, vacuoles of diverse sizes and shapes near the cell membrane or deep in the cell center were found to contain CD4 molecules. Negatively stained Golgi saccules were observed up to 45 min after re-incubation. These results suggest that increased CD4 molecules can be induced on the surface of normal human T-cells in vitro. Internalization and accumulation of CD4 molecules occurred in CD4-enriched T-cells with IL-2 pretreatment.

Adult↗
PubMed1992

Histologic changes of irradiated prostatic carcinoma diagnosed by transrectal ultrasound.

Digital rectal examination and transrectal ultrasound was used to evaluate the clinical status of 125 men previously treated for prostate carcinoma by definitive radiation. Transrectal ultrasound-guided biopsy of a hypoechoic lesion was performed on all 125 men, with 71.2% of them found to have persistent carcinoma. These irradiated carcinomas exhibited increased tumor aggressiveness by both histologic (Gleason score) and biologic (DNA ploidy) parameters. Following radiation therapy 30.6% of pretreatment diploid tumors were found to be aneuploid after treatment. Similarly, there was a 24% increase in the number of poorly differentiated (Gleason score 8 to 10) tumors following radiation therapy. A number of patients with persistent carcinoma postradiation therapy, but with clinically localized disease, may be "cured" by subsequent surgery. Salvage radical prostatectomy found localized cancer in 16 of 20 patients (80%). The use of transrectal ultrasound for early detection and staging was crucial for patient selection for definitive salvage therapy.

Aged↗
PubMed1992

The murine interleukin-4 receptor gene: genomic structure, expression and potential for alternative splicing.

The structure of the murine interleukin-4 receptor (mIL-4R) gene has been determined. The gene spans approximately 25 kilobases (kb) of DNA and is composed of 12 exons interrupted by 11 introns. The gene contains sequences accounting for all the sequences present in the functional mIL-4R cDNAs, including several exons which can encode DNA inserts found in recently cloned IL-4R cDNA variants. Thus expression of the gene may be regulated, at least in part, by alternative splicing. A combination of S1 nuclease protection and primer extension assays was used to localize the 5' end of the gene and demonstrated the use of multiple transcription initiation sites within this region. We have found that the overall intron-exon organization of the murine IL-4R gene is markedly similar to that of the murine erythropoietin receptor (m-epoR) and the human interleukin-2 receptor beta chain (hIL-2R beta), as well as the human growth hormone receptor (hGhR). This is consistent with the recent grouping of these receptors, on the basis of protein sequence homology, into the hematopoietin receptor gene superfamily. Such homology at the levels of both protein and gene structure suggest a divergent evolution of the receptors from a single primordial gene.

Animals↗
PubMed1992

New-generation RIBA hepatitis C strip immunoblot assays.

Second-generation hepatitis C virus (HCV) ELISAs are currently in use in Europe and have been submitted for approval in the United States. These new assays contain additional antigens from the putative nucleocapsid and NS-3 regions of the HCV genome in addition to the c100-3 antigen present in first-generation ELISAs. A supplementary test, the second-generation RIBA HCV strip immunoblot assay (2-RIBA HCV SIA) has also been developed. The strip immunoblot assay uses four recombinant HCV antigens [5-1-1 (NS-4), c100-3 (NS-4), c33c (NS-3), and c22-3 (NS-3) (nucleocapsid)] slot blotted on nitrocellulose. Screening of random volunteer blood donors with the Ortho second-generation HCV ELISA (ORTHO HCV 2.0 ELISA) indicates that a substantial change in the repeat reactive donor population is observed with the new test. Two notable features of this change are: (1) A large number of samples reactive in the 2-RIBA HCV SIA for the second-generation antigens, c33c and c22-3, are detected by the ORTHO HCV 2.0 ELISA; (2) the percentage of ORTHO HCV 2.0 ELISA reactive specimens found indeterminate (reactive for only one HCV antigen) by the 2-RIBA HCV SIA is higher than in first-generation HCV ELISAs (approximately 25 vs. 5%). In addition, ORTHO HCV 2.0 ELISA repeat reactive, 2-RIBA HCV SIA indeterminate samples are dominated by reactivity to c22-3 instead of c100-3, which is the case for first-generation HCV ELISA repeat reactive samples. Resolution of 2-RIBA HCV SIA indeterminate samples as either containing anti-HCV antibodies or not, is important in both diagnostic and blood screening environments, especially where donor notification is required. Our approach to resolution of these troublesome samples evolved from initial work with HCV peptides. Early studies with an experimental strip immunoblot assay containing 5 peptides from the nucleocapsid, E2 (NS-1), NS-4, and NS-5 regions of the viral genome indicated that peptides from the nucleocapsid and NS-4 regions of the genome could provide additional evidence for the presence of anti-HCV antibodies with good specificity, but other peptides suffered from poor specificity. In addition, no immunoreactive peptide from the NS-3 (c33c) region of the virus is available, presumably because the major epitope(s) of this key second-generation antigen is a conformational determinant.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Transfusion↗
PubMed1992

New generation RIBA hepatitis C strip immunoblot assays.

Second generation hepatitis C virus (HCV) Elisas are currently in use in Europe and have been submitted for approval in the United States. These new assays contain additional antigens from the putative nucleocapsid and NS-3 regions of the HCV genome in addition to the c100-3 antigen present in first generation Elisas. A supplementary test, the second generation RIBA (Chiron Co trademark) HCV strip immunoblot assay (2-RIBA HCV SIA) has also been developed. The strip immuno-blot assay uses four recombinant HCV antigens (5-1-1 [NS-4], c100-3 [NS-4], c33c [NS-3], and c22-3 [NS-3 [nucleocapsid]) slot blotted on nitrocellulose. Screening of random volunteer blood donors with the Ortho (Ortho Diagnostic Systems trademark) second generation HCV Elisa (2-Ortho HCV Elisa) indicates that a substantial change in the repeat reactive donor population is observed with the new test. Two notable features of this change are: i) a large number of samples reactive in the 2-RIBA HCV SIA for the second generation antigens, c33c and c22-3, are detected by the 2-Ortho HCV Elisa; ii) the percentage of 2-Ortho HCV Elisa reactive specimens found indeterminate (reactive for only one HCV antigen) by the 2-RIBA HCV SIA is higher than in first generation HCV Elisas (approximately 25 versus 5%). In addition, 2-ortho HCV Elisa repeat reactive, 2-RIBA HCV SIA indeterminate samples are dominated by reactivity to c22-3 instead of c100-3 which is the case for first generation HCV Elisa repeat reactive samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Diagnosis of human immunodeficiency virus infection by enzyme-linked immunospot assays in a prospectively followed cohort of infants of human immunodeficiency virus-seropositive women.

The enzyme-linked immunospot (ELISPOT), a method for quantifying specific and total antibody-secreting cells, was used for the diagnosis of human immunodeficiency virus (HIV) infection in a prospectively followed cohort of infants born to HIV-infected women. From July 1, 1987, to June 1, 1990, 127 infants with known HIV infection status were studied. Seventeen of 22 HIV-infected infants had specific HIV-specific antibody-secreting cells (ASC). Among the infected infants rates of ASC positivity increased during the first year of life, from 25% in the first 5 days of life to 78% after 6 months. Two of the five ASC-negative infected infants were further characterized as hypo- or dysgammaglobulinemic by an adjunct ELISPOT assay for total immunoglobulin-secreting cells. Excluding hypo- or dysgammaglobulinemic infants from the analysis, the rate of ASC positivity among infected infants was 85% (17 of 20) after the age of 6 months. None of the 95 uninfected infants had a positive ELISPOT assay, including 55 who were tested in the first 3 months of life. Thus in this series the specificity was 100%. ELISPOT methodology can be a useful technique for the diagnosis of HIV infection in infants of HIV-seropositive mothers.

Female↗
PubMed1991

Interleukin-7 induces the proliferation of normal human B-cell precursors.

In the present study, we investigated the effects of human recombinant interleukin-7 (IL-7) on the proliferation of enriched hematopoietic cells isolated from human adult and fetal bone marrow (BM). In cultures of CD34+ cells, IL-7 was found to induce dose-dependent incorporation of 3H-thymidine (3H-TdR), but had no demonstrable effect on the development of myeloid colony-forming cells. Numbers of B-cell precursors (BCP), initially present within CD34+ populations and which included a CD34+CD20+ subset, were significantly increased when CD34+ BM cells were cultured in the presence of IL-7. This effect was most striking on CD20+ BCP, and resulted at least partly from higher numbers of cycling cells as indicated by Hoechst 33342 fluorescence (Calbiochem, Behring Diagnostics, La Jolla, CA). These results indicate that IL-7 promotes the growth of BCP within the CD34+ compartment. In line with the B-lineage affiliation of CD34+ target cells, committed BCP (CD10+ CD19+ surface IgM-) isolated from BM were also found to proliferate in response to IL-7. Interestingly, this effect of IL-7 was strongly potentiated by the addition of IL-3. Taken together, and in accordance with previous observations on murine cells, our data indicate that IL-7 acts as a growth factor during the ontogeny of human B lymphocytes.

Adult↗
PubMed1991

The maintenance of lytic specificity during the development of clones of cytotoxic T lymphocytes from single precursor cells.

A high-cloning efficiency, filler cell-free limit-dilution culture system for the growth and differentiation of single cytotoxic T lymphocyte precursors (CTLp) was tested for its ability to maintain the lytic specificity of the resultant clones of cytotoxic T lymphocytes (CTL). The system used non-specific stimulation with phorbyl ester and calcium ionophore, maintenance of growth over the first 6 days of culture with interleukin (IL)-2 and interferon-gamma, and maintenance of growth and differentiation over the last 2 days of culture with IL-2 and IL-6. Under these defined conditions around 50% of all CD4- 8+ T cells developed into CTL clones that were specific in their lytic activity. In contrast, a culture system maintained by irradiated filler cells showed non-specific lysis of both YAC-1 type natural killer targets and of P815 type targets, while a culture system maintained by IL-2 and a crude growth factor preparation showed non-specific lysis of natural killer targets but not of P815. The defined lymphokine culture system was suitable for determining the specificity repertoire of primary CTLp. Using this system, the frequency of reactivity with allogenic tumor targets was found to be approximately one CTLp in 30 for several mouse strain/target cell combinations.

Animals↗
PubMed1991

The American Cancer Society National Prostate Cancer Detection Project. Findings on the detection of early prostate cancer in 2425 men.

The American Cancer Society National Prostate Cancer Detection Project (ACS-NPCDP) is a multidisciplinary, multicenter effort to assess the feasibility of early prostate cancer detection by digital rectal examination (DRE), transrectal ultrasound (TRUS), and prostate specific antigen (PSA) assay. By June 1990, 2425 men not previously suspected of having prostate cancer had been examined in ten participating clinical centers according to the project protocol. Three hundred ninety-six men (16.3%) were recommended for biopsy on the basis of TRUS or DRE. An analysis of the results of 330 completed biopsies showed 52 cancers detected by DRE and/or TRUS. Forty-four (84.6%) of the men with cancer had positive TRUS examination results compared with 33 (63.5%) with positive DRE. Five additional cancers were discovered as a result of elevated PSA levels. The overall detection rate was 2.4% and this rate varied by age. The detection rate in men 55 to 60 years of age was 1.3% and this rose to 3.3% in men older than 65 years of age. The estimated sensitivity was significantly greater for TRUS compared with DRE (77.2% versus 57.9%; P less than 0.05). The estimated specificity of DRE was greater than that of TRUS (96.3% versus 89.4%; P less than 0.01). The positive predictive value (PPV) for the tests varied as a function of patient and disease characteristics. The overall PPV was 28.0% for DRE and 15.2% for TRUS. The occurrence of elevated PSA levels significantly increased the PPV of both TRUS and DRE. The majority of cancers detected were at early stages. These preliminary data suggest the feasibility of using these techniques to promote cancer control, but additional data and follow-up are needed to assess the significance of the results.

Age Factors↗
PubMed1991

Identification of a novel human thymocyte subset with a phenotype of CD3- CD4+ CD8 alpha + beta-1. Possible progeny of the CD3- CD4- CD8- subset.

We investigated responsiveness to cytokines and differentiating potential of early human T cell precursors in vitro. Human CD3- CD4- CD8- (triple negative) thymocytes were highly purified by using magnetic bead columns and cell sorting. These cells proliferated for the first 3 to 4 days and then remained viable for up to 14 days in the presence of IL-7, IL-2 or IL-4 had only limited growth-promoting activity on these cells and could not maintain the cell viability. We followed the phenotypic change of triple negative thymocytes during culture with IL-7. After 7 to 14 days of culture with IL-7, a considerable proportion became CD4+ CD8+ (double positive). These cells were found to be CD3- CD4+ CD8 alpha+ beta- in contrast to common double positive thymocytes, which express low levels of CD3 and both alpha- and beta-chains of CD8. By using four-color immunofluorescence and multi-parameter cytofluorometric analysis, we could identify this novel subset in fresh thymocytes. These results suggest that the CD3- CD4+ CD8 alpha+ beta- subset exists physiologically in the human thymus and may represent an intermediate stage between triple negative and common double positive thymocytes.

Antigens, CD↗
PubMed1991

Prostate cancer: transrectal ultrasound and pathology comparison. A preliminary study of outer gland (peripheral and central zones) and inner gland (transition zone) cancer.

A study was conducted to compare results of transrectal ultrasound with pathologic findings on 116 patients who underwent radical prostatectomy for treatment of prostate cancer. In 96% (111 of 116), transrectal ultrasound guided biopsies of a hypoechoic lesion proved cancer; seven patients had known Stage A cancer; one patient had cancer detected by palpation and not detected by ultrasound. Cancers in the outer gland (peripheral and central zones) were compared with cancers in the inner gland (transition zone) by both ultrasound and pathology. Forty-eight percent (52 of 108) of cancers originating in the outer gland showed extraprostatic extension (Stage C disease). The primary sites of tumor escape from the outer gland were the prostatic capsule (38%), anterior fibromuscular stroma (5%), seminal vesicle (18%), the base of the gland at the neurovascular bundle (21%), and the apex (31%). Twenty-two percent (17 of 54) of cancers originating in the inner gland (transition zone) showed extraprostatic extension (Stage C disease). The primary sites of tumor escape from the inner gland were the anterior fibromuscular stroma (6%) and apex (11%). Both histologic and biologic differences between outer and inner gland cancers were found when tumor size was controlled. Gleason scores were significantly different for inner and outer gland cancers, with mean scores of 6.2 +/- 1.6 and 7.4 +/- 0.9, respectively. An odds ratio of 8.6 confirmed the increased risk of extraprostatic extension for outer gland cancer. Outer gland cancers showed increased aggressive behavior of both histologic and biologic nature. The difference in biologic aggressiveness of outer and inner gland cancers has definite implications for treatment options. Use of other diagnostic parameters, such as DNA ploidy, may help to determine which cancers to treat and when to treat them; this may have more relevance for cancers originating in the inner gland. Strategic transrectal ultrasound guided biopsy affords accurate tumor mapping and staging when modes of internal spread and escape of cancer from both outer and inner gland are known. Thus, transrectal ultrasound may be our "window of observation" through which additional research may explain the histologic and biologic discrepancies between outer and inner gland cancers.

Adenocarcinoma↗
PubMed1991

Lymphokine requirements for the development of specific cytotoxic T cells from single precursors.

A high cloning efficiency, filler cell-free culture system was developed for the growth of single murine cytotoxic T lymphocyte precursors (CTLp) and their differentiation into cytotoxic T lymphocytes (CTL). The system used nonspecific stimulation with phorbol ester and calcium ionophore in the presence of recombinant lymphokines. The optimal lymphokine combination was interleukin 2 throughout, together with interferon-gamma during the first 6 days and interleukin 6 during the last 2 days of culture. Under these conditions half of all CD4-CD8+ T cells became CTL clones. The CTL were CD4-CD8+CD3+ TcR alpha/beta+ and were derived from CD4-CD8+Pgp-1- precursors.

Animals↗
PubMed1991

Differentiation of reperfused-viable (stunned) from reperfused-infarcted myocardium at 1 to 3 days postreperfusion by in vivo phosphorus-31 nuclear magnetic resonance spectroscopy.

Thrombolytic therapy has increased the need for a technique to assess the viability of recently reperfused myocardium. This study examined the ability of in vivo phosphorus-31 (P-31) nuclear magnetic resonance (NMR) spectroscopy to distinguish reperfused-viable (stunned) from reperfused-infarcted myocardium at 6, 30, and 54 hours following coronary artery occlusion in a canine model. A 15-minute occlusion produced reperfused-viable myocardium in five animals and a 360-minute occlusion produced reperfused-infarcted myocardium in six animals. Postreperfusion risk zone myocardial phosphocreatine (PCr) concentration measured by P-31 NMR spectroscopy was significantly depressed throughout the 3-day study period in infarcted but not in viable myocardium (p less than 0.01 between groups, all time points). The postreperfusion ratio of inorganic phosphate (Pi) to PCr concentration, as determined by NMR spectroscopy, was elevated throughout the study period in infarcted but not in viable reperfused myocardium (p less than 0.01 between groups, all time points). Postreperfusion Pi concentration was elevated at 6 hours but not subsequently in reperfused-infarcted myocardium, and was not elevated in reperfused-viable myocardium. Logistic regression models selected PCr concentration and the Pi/PCr ratio as providing the best discrimination between reperfused-viable and reperfused-infarcted myocardium. The accuracy of P-31 NMR variables selected by logistic regression analysis for determining myocardial viability ranged from 97% to 100%.

Animals↗
PubMed1991

Mechlorethamine, vinblastine, procarbazine and prednisolone (MVPP) for advanced Hodgkin's disease.

Between January 1972 and October 1985, 60 patients with advanced Hodgkin's disease were treated with mechlorethamine/vinblastine/procarbazine/prednisolone (MVPP). The complete remission (CR) rate was 50%; the introduction of computed tomography in 1980 reduced the proportion of CR from 62% to 30% (P = 0.017) as a consequence of residual mediastinal abnormality of uncertain significance. With a median follow-up of 9 years, actuarial 5 and 10-year overall survival was 70% and 57%, respectively, with 79% and 65% free from Hodgkin's disease. Only age and pathological subtype influenced survival sufficiently to be of prognostic significance, though the effect of serum albumin, ECOG performance status and B symptoms on Hodgkin's disease mortality may have been clinically important.

Adolescent↗
PubMed1991

Interleukin 1 alpha stimulates hemopoiesis but not tumor cell proliferation and protects mice from lethal total body irradiation.

Interleukin 1 alpha (IL-1) is a polypeptide/glycoprotein growth factor with multiple functions including the modulation of hematopoietic cell proliferation and differentiation. In vivo studies were performed with C57BL/6J mice injected with 0, 0.2, or 2.0 micrograms of IL-1 24 hr before or after lethal total body irradiation (TBI) (9.5 Gy). More mice in the groups administered IL-1 before TBI survived (90% of the 2.0 micrograms group) than those treated 2 or 24 hr after TBI, which was still slightly superior to the uninjected group, which all died within 15 days (p = .0001). Proliferation of bone marrow granulocyte/macrophage colonies following split dose TBI was also greatest for mouse groups treated with IL-1 prior to TBI. These experiments support data from other investigators that IL-1 stimulation of BM is related to IL-1 timing with respect to TBI. Stimulation of hemopoiesis was also assessed in terms of changes in peripheral blood and BM cell numbers and cell cycle kinetics using an electronic particle counter and flow cytometric techniques. Mice injected with 2 micrograms of IL-1 showed an initial decline (at 3-6 hr) and then a selective proliferation (24-48 hr) of early and more committed progenitor cells to 125% and 200% of control values, respectively. Peripheral blood counts rose accordingly. Cells in S and G2/M phases increased over 10 hr and then declined in number. It thus appeared that some synchronization of cell cycling occurred, which might place cells in a more radioresistant phase of the cell cycle. The glutathione (GSH) content and synthesis in BM cells were measured by isocratic paired-ion high performance liquid chromatography and 35S-labelled cysteine incorporation into the GSH tripeptide. An increase in cellular GSH content and synthesis was demonstrated following IL-1 which lasted 24 hr, suggesting a possible mechanism for the radioprotection by IL-1. To determine the potential for achieving a favorable therapeutic ratio, KHT tumor-bearing mice were injected with 2.0 micrograms IL-1. No change in tumor diameters or weights or tumor cell clonogenicity between IL-1 treated or untreated animals was observed. These experiments strongly support a role for IL-1 in stimulating bone marrow to overcome the myelosuppressive effects of irradiation.

Animals↗