Biomedical subjects

S Sell

Publications and source records attributed to S Sell.

At least 19 recordsLinked to original sources

PubMed1992

[Nuclear magnetic resonance tomography and sonography in diagnosis of lesions of the rotator cuff].

The diagnostic value of MRI and ultrasound in the examination of 37 patients with chronic shoulder pain is compared. All the results were controlled or by arthroscopy/arthrotomy or by arthrography. Ruptures and degenerative changes of the rotator cuff and degenerative lesions could be detected with a high sensibility. The ultrasound examination as a fast, reproducible diagnostic method has now become part of the routine diagnosis. The MRI produces exacter information about the extent of the lesions; but it will be reserved for special questions.

Arthroscopy↗

PubMed1992

[The spine--a problem area in high performance artistic gymnastics. A retrospective analysis of 24 former artistic gymnasts of the German A team].

24 former female artistic gymnasts of the German national team were examined for spinal deformities after the end of their athletic career. In 3 cases we found osseous lesions of the spine without neurological complications. However, emphasis was on spinal changes due to stress. During their athletic career 15 gymnasts complained of low back pain which persisted in 7 of them after finishing their athletic activities. The lumbar radiographs revealed bilateral spondylolysis at L5 in 6, unilateral spondylolysis in 1, spondylolisthesis at L5/S1 in 3, degenerative changes of the intervertebral joints in 5, retrolisthesis at L5/S1 in 2, and scoliosis in 6 cases.

Adult↗

PubMed1991

Synergy between hepatitis B virus expression and chemical hepatocarcinogens in transgenic mice.

Exposure of female hepatitis B virus transgenic mice of lineage 50-4, which display liver injury secondary to overexpression of the gene for the large envelope polypeptide of hepatitis B virus, to the hepatocarcinogens aflatoxin and diethylnitrosamine produced more rapid and extensive evidence of nodule formation and oval cell proliferation, as well as the development of adenomas and primary hepatocellular carcinomas, than was seen in transgenic mice not exposed to carcinogens. Adult mice are known to be resistant to the effects of aflatoxin or diethylnitrosamine, and the livers of carcinogen-treated nontransgenic littermate controls were essentially normal. By the time of sacrifice (15 mo), 20 adenomas and 2 primary hepatocellular carcinomas were found in 26 transgenic mice given aflatoxin and 8 adenomas and 2 primary hepatocellular carcinomas were seen in the 8 mice exposed to diethylnitrosamine, but no adenomas or carcinomas were identified in the 10 transgenic mice not exposed to carcinogens. These results suggest that the chronic liver damage and repair caused by overexpression of the hepatitis B virus large envelope polypeptide in the hepatocytes of the transgenic lineage 50-4 act synergistically with chemical hepatocarcinogens to produce neoplasia of the liver.

Adenoma↗

PubMed1991

[Nuclear magnetic resonance tomography and ultrasound imaging of anatomic structures of the shoulder joint].

The possibilities of MRI and ultrasound in visualizing the structures of the shoulder joint are compared. Both methods have a good accuracy in detecting changes of the soft tissue of the shoulder. Changes of the cartilage and the bony structures are better seen in the MRI. The MRI gives a static and clear view of the shoulder joint, meanwhile the ultrasound depends on the dynamic examination. Ultrasound and MRI are both reproducible and non-invasive methods, who seem to complete one another at the examination of the shoulder.

Acromioclavicular Joint↗

PubMed1991

Protracted Treponema pallidum-induced cutaneous chancres in rabbits infected with human T-cell leukemia virus type I.

In a preliminary study, two of four rabbits infected with human T-cell leukemia virus type I (HTLV-I) demonstrated prolonged primary chancres following superinfection with Treponema pallidum, the causative agent of syphilis. Two rabbits inoculated with 1 x 10(7) HTLV-I-infected human MT-2 cells and two with infected rabbit cells from a line established in this laboratory (RLT-P), developed latent HTLV-I infection as detected by seroconversion 10 weeks after infection and by detection of HTLV-I sequences in the DNA of peripheral blood lymphocytes after amplification by polymerase chair reaction (PCR) 15 weeks after infection. The rabbits remained clinically normal and had normal blood counts. Six months after infection, the four HTLV-infected rabbits and two noninfected controls were challenged by the intradermal inoculation of 1 x 10(6) Treponema pallidum into eight sites on the shaved back. The lesions of two of the HTLV-I-infected rabbits had a time course similar to non-HTLV-I-infected controls and were completely healed by 4 weeks. The lesions of one of the other two rabbits with progressive disease began to heal about 7 weeks after T. pallidum challenge. The cutaneous lesions in the other rabbit remained dark-field positive and became a confluent eschar at 8 weeks; healing only after treatment with penicillin. Four months after the primary challenge none of the six rabbits previously challenged with T. pallidum had developed lesions after rechallenge and thus expressed chancre immunity. These results demonstrate that rabbits with latent HTLV-I infections may have defective cell-mediated immunity.

Animals↗

PubMed1991

Contribution of rabbit leukocyte defensins to the host response in experimental syphilis.

In the companion paper (L. A. Borenstein, M. E. Selsted, R. I. Lehrer, and J. N. Miller, Infect. Immun. 59:1359-1367, 1991), we report that rabbit alveolar macrophage and neutrophil derived defensins possess antimicrobial activity against Treponema pallidum subsp. pallidum, the etiologic agent of syphilis. In this study, antisera specific for NP-1 and NP-2 (defensins present in certain macrophages and polymorphonuclear leukocytes) and NP-5 (a defensin produced only in neutrophils) were used to detect these peptides by immunoperoxidase staining in testicular lesions from infected rabbits. Profound amounts of cell-free and cell-associated defensins were detected in the tunica albuginea and interstitial spaces during the first 24 h of infection. The presence of defensins was transient and almost undetectable by day 4. Interstitial defensins were detected again at day 10 and increased through day 16, at which time lesion healing was evident by hematoxylin and eosin staining. The appearance and increase in detectable defensins between days 10 and 16 of infection correlated with a reduction in numbers and disappearance of T. pallidum, as demonstrated by using silver staining. The extent and pattern of immunostaining for NP-1 and NP-2 corresponded with immunostaining for NP-5 and identified neutrophils as the cellular source of the defensins. These findings indicate that defensins may contribute to the control of local T. pallidum infection and suggest a role for acute inflammatory processes in the resolution of early experimental syphilis.

Animals↗

PubMed1991

Syphilis superinfection activates expression of human immunodeficiency virus I in latently infected rabbits.

Superinfection of latently human immunodeficiency virus (HIV)-infected rabbits with either Treponema pallidum or Shope fibroma virus (SFV) activates HIV expression. In addition, HIV-infected rabbits demonstrate prolonged cutaneous lesions (chancres) after intracutaneous challenge with T. pallidum, the causative agent of syphilis. Rabbits were infected by intravenous inoculation of 3 x 10(7) human T-cell lymphotrophic virus type III (HTLV-III)/B10 (HIV-1)-infected H9 (human) cells. Five weeks after initial infection, integrated HIV-1-specific DNA sequences were detected in the DNA of the peripheral blood lymphocytes of only one of eight rabbits using polymerase chain reactions (PCR); human DNA could not be detected at this time. Furthermore HIV infection could not be demonstrated by either seroconversion or PCR during the next 6 months. All HIV-infected rabbits remained clinically healthy and had normal white blood cell counts. Six months after HIV infection, four HIV-infected and two noninfected controls were superinfected with 10(6) T. pallidum in eight skin sites in the shaved skin of the back, and four infected and two control animals were challenged with an intradermal injection with SFV. After infection with either syphilis or SFV, the DNA from the white blood cells of all eight HIV-infected rabbits contained HIV sequences, and HIV sequences were demonstrated in dermal mononuclear cells of the syphilitic lesions by in situ hybridization. The SFV-induced tumors were rejected normally in the HIV-infected rabbits, but four of the four rabbits challenged with T. pallidum had delayed development of cutaneous lesions and three of four demonstrated larger and more prolonged lesions. White blood counts, mitogen responses, and interleukin-2 production remained within normal limits, and seroconversion for HIV was not detected. Three of four rabbits in a second group, challenged with T. pallidum 4 months after HIV-inoculation, also had delayed healing of syphilitic lesions. These results indicate that latent HIV-infection of rabbits may be activated by immunostimulation and that latently HIV-infected rabbits have impaired delayed hypersensitivity reactions. It is hypothesized that true latent HIV-infection in the rabbits is in monocytes and postulated that further immunostimulation may produce infection of lymphocytes and activation of disease.

Animals↗

PubMed1991

[Continuous passive motion in the after care of knee joint prostheses].

Since 1982 there have been many reports on the use of continuous passive motion in the postoperative care of patients with total knee arthroplasty. Continuous passive motion (CPM) has proven to provide good results at our clinic. CPM is often described as having a positive effect on the postoperative range of motion. It also seems to decrease the length of the hospital stay. In addition, a low incidence of thrombosis has been reported and we could detect no negative effects on wound healing.

Adult↗

PubMed1990

Is there a liver stem cell?

The role of a putative liver stem cell in liver regeneration and carcinogenesis is reviewed. There is increasing evidence that there is a liver stem cell that has the capacity to differentiate into parenchymal hepatocytes or into bile ductular cells. These stem cells may be activated to proliferate after severe liver injury or exposure to hepatocarcinogens. They are not activated by moderate liver injury, which is repaired by proliferation of mature hepatocytes. Exposure to most chemical hepatocarcinogens results in proliferation of a small morphologically indistinct cell population termed "oval cells." These cells have been shown to have the capacity to differentiate into hepatocytes or into ductular cells. The origin of these cells appears to be from transition duct cells, but there is also evidence of an even less mature periportal liver stem cell. Study of the development of these cells during carcinogenesis indicates that liver cancer arises from oval cells by aberrant differentiation of stem cells.

2-Acetylaminofluorene↗

PubMed1990

Hepatocarcinogenesis due to chronic liver cell injury in hepatitis B virus transgenic mice.

Fifty-nine transgenic mice from a lineage that overproduces the hepatitis B virus large envelope polypeptide and accumulates high intrahepatic concentrations of hepatitis B surface antigen were followed for evidence of liver disease throughout their 24-month life span. By 4 months of age all mice displayed biochemical and histological evidence of moderately severe chronic hepatitis which was followed sequentially by the development of regenerative nodules and oval cell hyperplasia (by 6 months), liver cell adenomas (by 8 months), and hepatocellular carcinomas (by 12 months of age). One hundred % of mice in this lineage developed hepatocellular carcinoma by 20 months of age, whereas no histopathological changes were observed in age- and sex-matched nontransgenic littermate controls over the same period of observation. These results indicate that overproduction of the hepatitis B virus large envelope polypeptide initiates a process characterized by liver cell injury, inflammation, and regenerative hyperplasia, which places large numbers of hepatocytes at risk for the development of transforming mutations, and inexorably progresses to hepatocellular carcinoma. We suggest that this is a general mechanism of hepatocarcinogenesis that may be operative in human hepatitis B virus infection and other necroinflammatory liver diseases as well.

Adenoma↗

PubMed1990

Molecular signals in B cell activation. I. Differential refractory effects of incomplete signaling by ionomycin or PMA relate to autocrine IL-2 production and IL-2R expression.

The molecular signals required by resting (G0) B cells for the induction of cell cycle entry, IL-2 production, and high-affinity IL-2 receptor (IL-2R) expression were defined and the effects of incomplete activation signals on the subsequent response to complete signals were examined. Highly enriched rabbit peripheral blood B cells were activated with a calcium ionophore, ionomycin, and a protein kinase C (PKC) activating phorbol ester, phorbol myristate acetate (PMA). It was observed that cell cycle entry to early G1 was induced by either reagent acting alone, but both reagents were required to stimulate IL-2 production, IL-2R expression, and DNA synthesis. These effects of ionomycin and PMA were shown to be mediated by increased intracellular calcium ion concentration [Ca2+]i and PKC activation, respectively. Although, increased [Ca2+]i or PKC activation each led to cell cycle entry, the subsequent response of these preactivated cells to complete activation with both signals was different: Cells pretreated with PMA alone for up to 24 hr could progress further to DNA synthesis after the addition of ionomycin. In contrast, cells activated with ionomycin alone, or those cultured without any stimulus, progressively lost the ability to show DNA synthesis after complete activation. The failure to progress to DNA synthesis in these two cases was, however, differentially regulated by the ability of these cells to produce IL-2 and to express IL-2R. Ionomycin-pretreated cells retained the ability to produce IL-2 but showed about 70% reduction in the numbers of IL-2R; whereas cells cultured without any stimulus lost the ability to produce IL-2 after subsequent complete activation, but showed lesser reduction in IL-2R expression.

Animals↗

PubMed1990

Molecular signals in B cell activation. II. IL-2-mediated signals are required in late G1 for transition to S phase after ionomycin and PMA treatment.

We report that sustained increase of intracellular calcium ion concentration and protein kinase C (PKC) activation maintained throughout the G1 phase of cell cycle do not provide sufficient signals to cause S-phase entry in rabbit B cells, and that additional signals transduced by IL-2 and IL-2 receptor interaction are essential for G1 to S transition. We have shown earlier that rabbit B cells can be activated to produce IL-2 and express functional IL-2 receptors after treatment with ionomycin and PMA. Herein we have compared the response of rabbit PBLs, which contain about 50% T cells, with those of purified B cells. After activation with ionomycin or PMA, comparable numbers of PBLs and B cells entered the cell cycle; but DNA synthesis by the PBL cultures was three to four times higher than that of cultures of purified B cells. Interestingly, IL-2 production by the PBL cultures was also three to four times higher than in B cell cultures, suggesting an involvement of IL-2 in inducing DNA synthesis in these cells. The hypothesis that IL-2, which is produced in early G1, acts in late G1 and is required for G1 to S transition in B cells was supported by the following observations: (i) IL-2 production by B cells was detected as early as 6 hr after activation and preceded DNA synthesis by at least 24 hr. (ii) B cell blasts in G1 (produced by treatment of resting B cells with ionomycin and PMA) showed DNA synthesis in response to IL-2, but showed very little DNA synthesis in response to restimulation with ionomycin and PMA. (iii) A polyclonal rabbit anti-human IL-2 antibody caused nearly complete inhibition of DNA synthesis by B cells activated by ionomycin and PMA. (iv) A PKC inhibitor, K252b, inhibited DNA synthesis in ionomycin and PMA-stimulated cells if added at the beginning of culture but was not inhibitory if added 16 hr later. We conclude that increased [Ca2+]i and PKC activation are not sufficient signals for G1 to S transition in B cells; entry into S is signaled by IL-2, and IL-2-mediated signal transduction probably does not involve increased [Ca2+]i or PKC activation.

Animals↗

PubMed1990

Natural cell-mediated immunity in the rabbit.

Susceptibility and resistance to tumors represent the interplay of many factors. One factor felt to govern the development of tumors is natural killer and natural cytotoxic cellular activity. The constitutional resistance of rabbits to spontaneous tumor development raises questions regarding the activity of natural cell-mediated immunity in this species. We therefore examined the ability of rabbit spleen, lymph node, and peripheral blood lymphocytes to mediate natural killer cell (NK) and natural cytotoxic cell (NC) activity in vitro. Using classical approaches to the study of NK and NC activity, we found no evidence of these activities in leporine spleen, lymph node, and peripheral blood lymphocytes. Preincubation of these cells with IL-2 did not induce such activity. Antibody-dependent cell-mediated cytotoxic reactivity (ADCC), which is believed to be mediated by NK cells, was also undetectable in rabbit lymphocytes. As controls, lymphocytes from other species were capable of mediating NK, NC, and ADCC functions normally in these experiments. Finally, we were unable to identify a population of large granular lymphocytes, the cells believed to mediate NK activity in other animals. Therefore, we could not demonstrate in the rabbit either natural cell-mediated immunity or the population of cells usually associated with natural cell-mediated immunity. If such activity exists in rabbits, it is different from that seen in other animals. More likely, the basis for the natural resistance of rabbits to tumor development must be sought elsewhere.

Animals↗

PubMed1990

Cancer-associated carbohydrates identified by monoclonal antibodies.

"New" carbohydrate structures on the surface of or secreted by cancer cells, identified as epitopes by monoclonal antibodies, are reviewed. These structures may represent the accumulation of precursor chains because of decreased activity of synthesizing enzymes, the production of new oligosaccharides due to increased or aberrant glycosylation of carbohydrate chains, a change in density of carbohydrates on the cell surface, or exposure of chains usually covered by other structures. Alterations in glycolipid synthesis include aberrant fucosylation and/or sialyation of the lacto series, sialylation or fucosylation of the globo series, and sialyation of the ganglio series. Many of these carbohydrate epitopes have become useful for the diagnosis, prognosis, and monitoring of patients with cancer. Some of the important markers include CA 15.3, CA 19.9, CA 50, CA 125, CA 242, MCA, SLEX, etc. Incomplete glycosylation of O-linked mucin oligosaccharide is recognized as the important "cancer antigen" B72.3, which is sialyated Tn. The oligosaccharide components of alpha-fetoprotein, carcinoembryonic antigen, and epidermal growth factor receptor are also reviewed. In many instances the glycosylation seen in cancer cells or their products reflects patterns seen during normal development. Thus, cancer-associated oligosaccharides are oncodevelopmental in nature. The biologic significance of carbohydrates on cell surfaces is not known, but several possibilities include a role in cell to cell recognition, intracellular processing of glycoproteins, cell activation, and ability of cancer cells to metastasize.

Antibodies, Monoclonal↗

PubMed1990

Interleukin 2 produced by activated B lymphocytes acts as an autocrine proliferation-inducing lymphokine.

Normal peripheral blood B cells produce a soluble factor after activation that is functionally indistinguishable from interleukin 2 (IL 2) and can support B cell proliferation in vitro. Purified rabbit peripheral blood B cells, when stimulated with a combination of ionomycin (0.5 microgram/mL) and phorbol myristate acetate (PMA) (1 ng/mL), secreted a soluble factor in the culture medium that supported the IL 2-dependent cell line CTLL-2. The ability of these supernatants to support CTLL-2 growth was almost completely blocked by rabbit antibodies against human recombinant IL 2 and by the anti-IL 2 receptor monoclonal antibody 7D4. These data strongly suggest that the growth factor secreted by rabbit B cells is IL 2. To examine the possibility that the IL 2 activity detected in the B-cell cultures may be derived from residual T cells, B cells were further purified by successive panning with a pan-T-cell monoclonal antibody, L11-135, and goat anti-rabbit IgG. These highly purified B cells produced levels of IL 2 activity comparable to those produced by the initial B cell populations. Comparison of IL 2 production by decreasing numbers of purified T cells and purified B cells also indicated that the B cells were the source of IL 2 activity. Supernatants of activated B cells could support proliferation of B-cell blasts, and this activity could be completely absorbed by CTLL-2 cells, indicating that IL 2 is a major growth factor for B cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Cancer markers of the 1990s. Comparison of the new generation of markers defined by monoclonal antibodies and oncogene probes to prototypic markers.

Markers found in the blood of cancer patients may be used to make the diagnosis of cancer, determine the prognosis of a patient with cancer, and monitor the effects of therapy. In this review, the results using the prototype markers--monoclonal immunoglobulins, alphafetoprotein, and carcinoembryonic antigen--are compared with those found with a number of more recently identified markers detected by monoclonal antibodies and oncogene products detected immunologically or by "anti-sense" probes. Although a "magic marker" for cancer has not been found, the systematic application of the appropriate set of markers for a given patient can add vital information that is not obtainable by other means.

Antibodies, Monoclonal↗

PubMed1990

Markers for hepatocellular carcinoma.

Markers for hepatocellular cancer include the best and worst of cancer detection. Although hepatocellular cancer is relatively infrequent compared to other cancers in the western world, HCC has a very high incidence in parts of Asia and Africa. It is estimated to be one of the most common cancer worldwide. High risk factors for HCC include previous hepatitis B infection, heavy alcohol consumption, cirrhosis, and aflatoxin exposure. Alpha fetoprotein may be the best human cancer marker that appears in the serum, but levels of this marker are often not elevated until the tumor is beyond surgical treatment. No other serum or tissue marker is particularly useful. Screening of high-risk populations in China has detected previously undiagnosed HCC in 1,000 of 5 million individuals tested and has led to an increase in survival from 5.5 to 61.6% with surgical resection over those who are later diagnosed with HCC without screening. Elevations of AFP due to yolk sac tumors may be differentiated from those due to HCC on the basis of Concanavalin A reactivity. Immunodetection using radiolabeled anti-AFP and immunoscintigraphy have given inconsistent results that are not as sensitive as ultrasonography in detecting HCC in the liver. Various enzymes, isoenzymes, and other markers may be useful as adjuncts to diagnosis in selected cases, but are not generally as good as AFP alone. If a patient has an AFP-producing tumor, the serum levels of AFP provide an excellent means of monitoring its progression. If the serum AFP levels drop to normal and stay there, cure is almost certain. If, however, the serum AFP level does not fall at the normal catabolic rate after therapy, or subsequently rises, regrowth of metastases are indicated. Immunotherapy using anti-AFP has not been shown to induce remission, but experimental studies indicate that drug-conjugated anti-AFP is effective in inhibiting growth of AFP-producing tumors. Clinical trials using drug-conjugated anti-AFP are now underway. Monoclonal antibodies have not yet identified the "antigens" useful for the diagnosis or treatment of HCC, but epitopes identified by monoclonal antibodies have been studied experimentally in rats which indicate multiple cellular lineages to HCC in cases of experimental chemically induced hepatocarcinoma.

Antigens, Neoplasm↗

PubMed1989

Molecular pathogenesis of hepatocellular carcinoma in hepatitis B virus transgenic mice.

Transgenic mice that overproduce the hepatitis B virus large envelope polypeptide and accumulate toxic quantities of hepatitis B surface antigen (HBsAg) within the hepatocyte develop severe, prolonged hepatocellular injury that initiates a programmed response within the liver, characterized by inflammation, regenerative hyperplasia, transcriptional deregulation, and aneuploidy. This response inexorably progresses to neoplasia. The incidence of hepatocellular carcinoma in this model corresponds to the frequency, severity, and age of onset of liver cell injury, which itself corresponds to the intrahepatic concentration of HBsAg and is influenced by genetic background and sex. Thus, the inappropriate expression of a single structural viral gene is sufficient to cause malignant transformation in this model. These results suggest that severe, prolonged cellular injury induces a preneoplastic proliferative response that fosters secondary genetic events that program the cell for unrestrained growth.

Aging↗