Biomedical subjects

H Shapiro

Publications and source records attributed to H Shapiro.

At least 37 records · Page 2Linked to original sources

PubMed1998

Case-based reasoning in IVF: prediction and knowledge mining.

In vitro fertilization (IVF) is a medically-assisted reproduction technique, enabling infertile couples to achieve successful pregnancy. Given the unpredictability of the task, we propose to use a case-based reasoning system that exploits past experiences to suggest possible modifications to an IVF treatment plan in order to improve overall success rates. Once the system's knowledge base is populated with a sufficient number of past cases, it can be used to explore and discover interesting relationships among data, thereby achieving a form of knowledge mining. The article describes the TA3IVF system--a case-based reasoning system which relies on context-based relevance assessment to assist in knowledge visualization, interactive data exploration and discovery in this domain. The system can be used as an advisor to the physician during clinical work and during research to help determine what knowledge sources are relevant for a treatment plan.

Artificial Intelligence↗

PubMed1998

Human lung cancer cell lines express cell membrane complement inhibitory proteins and are extremely resistant to complement-mediated lysis; a comparison with normal human respiratory epithelium in vitro, and an insight into mechanism(s) of resistance.

Human lung cancer expresses cell membrane complement inhibitory proteins (CIP). We investigated whether human lung cancer cell lines also express cell-membrane CIP molecules and whether the biology of CIP molecules in these cell lines differs from that of CIP in normal human respiratory epithelium in culture. The cell lines ChaGo K-1 and NCI-H596 were compared with normal human nasal epithelium in primary cultures in respect to the level of cell membrane CIP expression of membrane cofactor protein (MCP; CD46), decay-accelerating factor (DAF; CD55) and CD59, in respect to the level of cell resistance to complement-mediated lysis, and in respect to the contribution of cell membrane CIP to cell resistance against complement-mediated lysis. We found, using flow cytometry, that both human lung cancer cell lines expressed MCP, DAF and CD59, as did normal nasal epithelial cells. However, normal cells showed a large subpopulation of low DAF-expressing cells (60% of all cells) and a smaller subpopulation of high DAF-expressing cells (40%), while the lung cancer cell lines showed only one cell population, of high DAF expression. In addition, both lung cancer cell lines expressed higher MCP levels, and NCI-H596 cells showed higher levels of CD59. Cell resistance to complement-mediated lysis of both lung cancer cell lines was much higher than that of normal cells. Fifty percent normal human serum, under the same concentrations of complement activators, induced lysis of less than a mean of 10% of lung cancer cells, while lysing up to a mean of 50% of nasal epithelial cells. Lung cancer cell resistance to complement was due to its ability to prevent significant activation of complement upon its cell membrane, as manifested by a failure of complement activators to increase cell membrane deposition of C3-related fragments. The exact mechanism for this resistance remains obscure. Unexpectedly, neutralizing antibodies, anti-MCP and anti-DAF were entirely ineffective and anti-CD59 was only slightly effective (18% mean cell lysis) in increasing the susceptibility of the lung cancer cell lines to complement, while the same antibodies were very effective in facilitating complement-mediated lysis of the normal nasal epithelial cells (50% mean cell lysis with CD59 MoAb). On the other hand, detachment of DAF and CD59 by phosphatidylinositol-specific phospholipase C (PIPLC) from the lung cancer cell lines abrogated their resistance to lysis. We suggest that the biology of cell membrane CIP molecules in human lung cancer cell lines is different from that of CIP in normal respiratory epithelial cells. Human lung cancer cell lines are able to prevent significant complement activation upon its cell membrane and are therefore especially resistant to complement-mediated lysis. Complement resistance may serve this common and highly lethal human cancer as an escape mechanism from the body's immunosurveillance and prevent effective immunotherapy with tumour-specific MoAbs.

Antigens, CD↗

PubMed1998

Ovarian hyperstimulation following the sole administration of agonistic analogues of gonadotrophin releasing hormone.

Ovarian hyperstimulation following the sole administration of gonadotrophin-releasing hormone agonists (GnRHa) is exceedingly rare. We hereby report on two infertile patients undergoing in-vitro fertilization-embryo transfer who developed ovarian hyperstimulation under such circumstances. In both patients, GnRHa were administered using the 'long protocol' regimen. The first patient developed ovarian hyperstimulation on two occasions, with mid-luteal depot administration of triptorelin and with early follicular triptorelin, administered as daily subcutaneous injections. In both cycles, within 2 weeks of triptorelin therapy, massive ovarian multifollicular enlargement occurred, concomitant with high serum oestradiol concentrations, which resolved spontaneously following expectant management. The second patient developed ovarian hyperstimulation following daily injections of leuprolide acetate starting at the mid-luteal phase. The final stage of ovulation was triggered by human chorionic gonadotrophin (HCG) and 11 oocytes were retrieved. In-vitro fertilization resulted in embryo formation, but failed to result in pregnancy. The same phenomenon recurred in a subsequent cycle despite preventive pretreatment with an oral contraceptive. A negative GnRH test, performed just before HCG administration, suggested than an ongoing 'flare-up effect' was unlikely to cause ovarian stimulation. Ovarian hyperstimulation can occur following the sole administration of GnRHa irrespective of the preparation used and the administration protocol. Although spontaneous resolution is the rule, once this condition has developed, HCG administration and oocyte retrieval are feasible. This rare entity probably represents an exaggerated form of ovarian cyst formation following GnRHa administration, the underlying pathophysiology of which remains unresolved.

Administration, Cutaneous↗

PubMed1998

Cytokines modulate expression of cell-membrane complement inhibitory proteins in human lung cancer cell lines.

Human lung cancers overexpress several cell-membrane complement inhibitory proteins (CIP). These complement inhibitory proteins are membrane cofactor protein (CD46), decay-accelerating factor (DAF; CD55), and CD59 (protectin). These cell-membrane proteins have a wide normal tissue distribution, are known to protect normal host cells from homologous complement-mediated lysis, and are thought to facilitate tumor escape from immunosurveillance. To study whether proinflammatory cytokines that are involved in cancer growth can modulate cell-membrane CIP expression in lung cancer cells, we studied the effect of interleukin (IL)-1alpha, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma on two human lung cancer cell lines. ChaGo K-1 and NCI-H596 cell lines, undifferentiated carcinoma and lung adenosquamous carcinoma, respectively, were stimulated with different cytokines, and the effects of incubation time and cytokine concentration on cell-membrane CIP expression were studied. Cell-membrane CIP expression was evaluated using flow cytometry and cytokine effect was calculated as percent change in mean fluorescence intensity of each CIP molecule from its untreated control. We found that DAF was the lung cancer cell-membrane CIP molecule that was the most responsive to cytokine stimulation. Maximal stimulatory effect was usually noted 72 h after a cytokine was introduced. In ChaGo K-1 and NCI-H596 lung cancer cell lines, IL-1alpha and TNF-alpha increased DAF expression. IL-1alpha (100 U/ml/72 h) increased DAF expression up to a maximal mean of 45 and 48%, respectively, in comparison with untreated cells. TNF-alpha (1, 000 U/ml/72 h) increased DAF expression up to a mean of 131 and 46%, respectively. IFN-gamma (1 U/ml/72 h) increased DAF expression in NCI-H596 cells up to a mean of 100%, but had a slight inhibitory effect on DAF expression in ChaGo K-1 cells, decreasing expression by a mean of 17% in comparison with untreated cells. We conclude that cell-membrane DAF expression in the studied human lung cancer cell lines is modulated by IL-1alpha, TNF-alpha, and IFN-gamma, and speculate that cytokine-mediated modulation of cell-membrane DAF in human lung cancer cells might affect lung cancer cell biology.

Antigens, CD↗

PubMed1997

Lymphoma with multi gene rearrangement on the level of immunoglobulin heavy chain, light chains, and T-cell receptor beta chain.

A unique case with diffuse mixed malignant lymphoma was investigated for gene rearrangement on the level of T-cell receptor (TCR), heavy chain immunoglobulin (Ig), and both light chains. Cell phenotype was examined with immunofluorescence techniques using antibodies against surface immunoglobulins (SIg) and the kappa and lambda light chains. Monoclonal antibodies were used against CD3, CD4, CD5, CD8, CD10, CD19, CD22, HLA-DR, and TdT. Gene rearrangement analysis for monoclonality determination was carried out with restricted DNA (EcoR I and Hind III) hybridized with one of the following 32P-labelled probes: T-cell receptor (TCR beta), immunoglobulin heavy chain (JH), k light chain, and lambda light chain. Phenotyping of the cell population from the excised lymph node (LN) revealed the presence of 66% B-cells and 35% T-cells. Most of the B cells (94%) expressed mu heavy chain only. Expression of both light chains was negligible (k = 7% and lambda = 2%). Gene rearrangement, which indicates monoclonality, was positive on the level of TCR, Ig heavy chain, and both light chains. The data obtained suggests a neoplastic transforming event in lymphoid stem cells, which preceded the subsequent differentiation process into either B or T lymphoma.

Aged↗

PubMed1997

The feasibility of assessing women's perceptions of the risks and benefits of fertility drug therapy in relation to ovarian cancer risk.

OBJECTIVE: To determine the feasibility of asking women undergoing fertility treatment the maximum increased risk of ovarian cancer they would be willing to tolerate in order to take ovulation-induction drugs. DESIGN: A prospective pilot study of women attending fertility clinics over a 2-month period. SETTING: Two tertiary care fertility clinics in Toronto. PATIENT(S): Sixty-one English-speaking women were approached and 85% (n = 52) were enrolled. INTERVENTION(S): A self-administered questionnaire with fertility-specific questions. Thirty-eight women also were asked to complete standardized scales of anxiety and optimism. MAIN OUTCOME MEASURE(S): Women's report of the maximum level of lifetime risk of ovarian cancer they were willing to tolerate in order to undergo fertility treatment. RESULT(S): Seventy-nine percent were willing to accept an increased risk of ovarian cancer. Only 24% understood that treatment for ovarian cancer usually was not curative. CONCLUSION(S): A majority of patients were willing to tolerate a modest increase in their lifetime risk of ovarian cancer because of fertility treatment, most basing their estimate of acceptable risk on limited awareness of the issue.

Adult↗

PubMed1996

Flow cytometric analysis of the platelet surface area and surface density of glycoprotein IIb-IIIa of unactivated human platelets of various sizes.

Large (L) activated platelets exhibit greater aggregability and express more activated glycoprotein IIb-IIIa (GPIIb-IIIa) per cell and per unit surface area than small (S) activated platelets. We studied the binding of CD61 monoclonal antibody to GPIIb-IIIa on resting platelets and developed a new method for determining platelet surface area by flow cytometry. Using this method, we found that resting L platelets contain two times more GPIIb-IIIa per cell than S platelets but the same amount of GPIIb-IIIa per unit surface area. The data suggest that the greater aggregability of L platelets is likely to be due to increased activation and/ or expression of GPIIb-IIIa rather than to elevated density of unactivated GPIIb-IIIa on resting L platelets.

Blood Platelets↗

PubMed1996

Primary ovarian carcinoid tumors.

Primary ovarian carcinoid tumors were reviewed from Mayo Clinic and Colorado Tumor Registry data. A total of 17 patients with this diagnosis were identified. Histologic analysis of these carcinoid tumors revealed 9 (53%) were insular, 5 (29%) were trabecular, and 4 (26%) were strumal carcinoid with or without a mature dermoid component. There were 11 patients with stage I and 6 patients with stage III or IV disease at diagnosis. Carcinoid syndrome was found in 29% of patients. Pressure or pain with defecation was noted in 41% of cases. Recurrence of tumor occurred in 1 of 11 patients with suspected stage I disease 13 years after initial diagnosis. Overall survival was excellent in the 11 patients whose disease was confined to one ovary (100% 5-year survival), but only 1 of 6 patients survived (33% 5-year survival) if advanced stage at diagnosis. Systemic chemotherapy for advanced disease achieved a complete response in 1 patient and stable disease in another. Although rare, primary ovarian carcinoid tumors treated with surgery alone and found to be confined to the ovary can be expected to have an excellent overall outcome.

Adult↗

PubMed1996

Effect of protein intake on erythropoiesis during erythropoietin treatment of anemia of prematurity.

OBJECTIVE: To examine the effect of protein intake on the erythropoietic response of very low birth weight infants to treatment with recombinant human erythropoietin (rHuEPO). STUDY DESIGN: Twenty very low birth weight infants were enrolled in the study and 19 completed the 6 weeks of study. Weekly absolute reticulocyte counts, protein intakes, and growth, as well as selected markers of protein metabolism--prealbumin, albumin, and transferrin--were analyzed. Iron stores were estimated for each infant to exclude iron deficiency as a cause of anemia. The relationship between protein intake and absolute reticulocyte count was evaluated with a linear breakpoint analysis to account for any plateau in the relationship at higher protein intakes. RESULTS: Adequate iron stores were present in all infants, and transferrin concentrations correlated with measured total iron-binding capacity (r = 0.95, p = 0.0001). In the rHuEPO-treated infants, absolute reticulocyte count was significantly associated with protein intake up to 3.1 gm/kg per day and extending to 3.5 gm/kg per day (p = 0.041 to 0.032); beyond this point there was no longer any effect. Moreover, in comparison with the infants who received placebo, the rHuEPO-treated infants had a better daily percent weight gain for a protein intake up to 3.5 gm/kg per day (p = 0.016). CONCLUSIONS: In VLBW infants treated with rHuEPO, higher protein intake up to 3.1 to 3.5 gm/kg per day improved the erythropoietic response, and protein utilization for growth was improved. During treatment with rHuEPO, infants who receive adequate protein to achieve satisfactory growth also receive sufficient protein for erythropoiesis.

Anemia, Neonatal↗

PubMed1996

Model for outcomes assessment of antihistamine use for seasonal allergic rhinitis.

BACKGROUND: Drug selection for optimal treatment of common medical conditions may be difficult and involve many diverse factors. OBJECTIVE: The efficacy, safety, quality of life, and cost of treatment of seasonal allergic rhinitis with cetirizine, chlorpheniramine, or terfenadine were compared in a prospective, two-phase, randomized, single-blind clinical trial conducted in a managed care setting. METHODS: In phase I, which lasted 2 weeks, patients were randomized to receive one of the study drugs. In phase II, which lasted 4 weeks, the initial treatment was continued unless patients were dissatisfied, in which case they could be randomly assigned to receive another study drug. In both phases pseudoephedrine could be taken as needed. Patients kept daily diaries of symptoms and costs, and study drugs were evaluated at the end of each phase for efficacy, safety, and effect on quality of life by means of a validated questionnaire. A multiattribute outcomes assessment model for formulary decision making was used to rank the antihistamines. RESULTS: Physicians' and patients' assessments in phases I and II indicated that cetirizine and chlorpheniramine were significantly more effective than terfenadine (p < 0.05). Incidence of sedation in phase I and phase II was 40.5% and 16.7% for chlorpheniramine, 11.6% and 9.8% for cetirizine, and 6.7% and 5.1% for terfenadine, respectively. At the end of phase I, 28.9% of the patients treated with chlorpheniramine, 50% of the patients treated with terfenadine, and 69.4% of the patients treated with cetirizine were satisfied with their therapy and chose not to switch their medication. Quality of life scores improved most after treatment with cetirizine and least after treatment with terfenadine. CONCLUSION: The result of this trial indicate that antihistamine selection is best made with the use of a multiattribute evaluation that includes quality of life. In this study cetirizine was favored by patients and physicians most often, followed by chlorpheniramine and then terfenadine.

Adolescent↗

PubMed1996

Human nasal epithelium adsorbs complement C3-related fragments and expresses cell membrane complement regulatory proteins.

Recent evidence suggests that complement is activated in human nasal airways in inflammatory states. Activated complement protects the nasal mucosa against microorganisms, but also has the potential to lyse the host's normal cells. Complement-mediated cell lysis depends on adsorption of complement to the cell membrane and on uninterrupted activation of the complement cascade upon the same cell membrane. In the present study, the authors investigated first whether key complement components, C3-related fragments, are adsorbed to nasal epithelial cell membrane. Second, we investigated whether nasal epithelium expresses cell membrane complement regulatory proteins that are known as interruptors of complement activation. Studies were done using fresh nasal mucosa obtained at turbinectomies from allergic rhinitis and vasomotor rhinitis patients. In addition, in order to establish an in vitro model, studies were also done using primary cell cultures of nasal epithelium. We have found that complement C3-related fragments are present on cell membranes of fresh nasal epithelium and that C3-related fragments are adsorbed to the epithelial cell membrane in nasal mucosa tissue segments and in cell cultures that were incubated with autologous serum. Adsorption of C3-related fragments to the cell membrane of cultured nasal epithelial cells was found by flow cytometry analysis to be concentration-dependent. In addition, we found that nasal epithelium in fresh tissue and in cell culture express three cell membrane complement regulatory proteins: membrane cofactor protein (MCP, CD46), decay-accelerating factor (DAF, CD55), and CD59. Our findings in fresh nasal epithelium suggest that complement activation may occur upon the nasal epithelial cell membrane during inflammation in vivo and that nasal epithelium might regulate this complement activation. Our in vitro cell culture model will allow further investigations of complement activation and regulation upon the human nasal epithelial cell membrane.

Adolescent↗

PubMed1996

Effect of the number of core biopsies of the prostate on predicting Gleason score of prostate cancer.

PURPOSE: We determined the effect of the number of core biopsies of the prostate on predicting the Gleason score of the prostatectomy specimen. MATERIALS AND METHODS: The Gleason scores from 124 radical prostatectomy specimens were compared to those from preoperative core needle biopsies of the prostate. The number of cores obtained and tumor stage were compared regarding agreement in prostate cancer score. RESULTS: Four to 6 core biopsies yielded the best results, with agreement within 1 Gleason score in 75% of the cases. Further increases in the number of core biopsies did not improve results. Additionally, 37% of the well differentiated tumors on core biopsy were stage C. CONCLUSIONS: Gleason score from the core biopsy has limitations in respect to predicting prostatectomy tumor score and stage and, therefore, it is problematic for use in therapeutic decision making.

Analysis of Variance↗

PubMed1996

Sequencing of combined hyperthermia and photodynamic therapy.

Photodynamic therapy (PDT) and hyperthermia are two alternative tumor treatment modalities currently being investigated in clinical trials. It has been suggested that, due to the differences in cell-killing mechanisms, synergetic tumor responses may be achieved if the two modalities are combined in appropriate sequences. This hypothesis is tested in the current study by delivering graded PDT doses during a transient tumor reoxygenation period after a hyperthermia treatment, or delivering graded hyperthermia doses when the tumor becomes acidic and hypoxic after a PDT treatment. The results indicate that the latter combination sequence has a profound effect on tumor response. While treating the tumors with PDT followed by hyperthermia evokes a synergetic tumor response, reversing the sequence results only in an additive effect. Possible mechanisms associated with tissue oxygenation are discussed.

Animals↗

PubMed1995

Exercise versus overnight albumin excretion rates in subjects with type 1 diabetes.

Diabetic nephropathy is the leading cause of new cases of renal failure in the US and Europe. An elevated albumin excretion rate (AER) on an overnight urine sample is considered an early predictor of end-stage renal failure. An elevated AER on a post-exercise urine sample has previously been considered to be an even earlier marker of renal damage. In a longitudinal prospective study, 373 subjects with insulin-dependent (type 1) diabetes mellitus had a total of 714 renal evaluations, each of which included one exercise and two overnight urine collections for AER determinations. All subjects were at least 13 years old and had diabetes for at least 4 years. There was a strong correlation between exercise and overnight AERs (r = 0.74, P < 0.001). For the 60 subjects with an initial borderline increase of either overnight or exercise AER, the overnight AER values (7.6-20 micrograms/min) progressed first for 52% of subjects whereas the exercise AERs (41-114 micrograms/min) progressed first for 43% of subjects (5% had simultaneous elevations of both). For the 22 subjects in which an abnormal overnight (> 20 micrograms/min) or exercise (> 114 micrograms/min) value was detected first, 17 (77%) had an elevated exercise AER first, whereas only 4 (18%) had an elevated overnight AER first. This study shows that an increase of either the exercise or the overnight AER can occur first, dependent upon the level of abnormality being considered. The two tests correlate closely with one another.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

New connexin32 mutations associated with X-linked Charcot-Marie-Tooth disease.

Analysis of the connexin32 gene in patients with X-linked Charcot-Marie-Tooth disease shows mutations distributed throughout the molecule, with all domains affected except the fourth transmembrane domain and the distal carboxy terminus. Sequence analysis of DNA from 19 unrelated patients detected six novel mutations and three previously reported mutations. Identification of additional mutations extends the distribution of connexin32 mutations in X-linked Charcot-Marie-Tooth disease and shows that specific mutations recur in additional families.

Amino Acid Sequence↗

PubMed1994

B-cell malignancy after low grade T-cell lymphoma.

BACKGROUND: Low grade, small lymphocytic, non-Hodgkin's lymphoma, was diagnosed in a 38-year-old woman. Thirty months after the initial diagnosis was made, a population of lymphoid cells with pathologic morphology was found in the patient's peripheral blood (PB). Cell phenotyping was performed and monoclonality was analyzed in cells obtained from a removed lymph node (LN) and the PB of the patient. METHODS: The cell phenotype was examined with immunofluorescence techniques using antibodies against SIg and monoclonal antibodies against CD1, CD3, CD4, CD5, CD8, CD19, and the kappa, and lambda light chains. Gene rearrangement analysis for monoclonality determination was performed with restricted DNA (EcoRI, Hin-dIII and BamHI) hybridized with either 32P-labeled T-cell receptor DNA probe (TcR-beta) or immunoglobulin-heavy chain probe (JH). RESULTS: With regard to the cell population of the removed LN, cell phenotyping showed the predominance of CD4+ T-cells over a polyclonal B-cell population. Gene rearrangement analysis proved the monoclonal nature of the T-cells and the polyclonal nature of the B-cells. As to the PB, gene rearrangement and cell phenotyping of the lymphocytes showed the predominance of monoclonal kappa type B-cells over polyclonal T-cells. CONCLUSIONS: The data obtained suggest two unrelated lymphoproliferative diseases in this patient, expressed as monoclonal T-cell population in LN and as monoclonal B-cell population in PB.

Adult↗

PubMed1993

The use of vaginal ultrasound for monitoring endometrial preparation in a donor oocyte program.

OBJECTIVE: To determine whether vaginal sonographic measurements can be used to monitor the endometrial preparation of recipients in a donor egg program. DESIGN: Prospective clinical trial. SETTING: University hospital-based IVF and donor egg program. PATIENTS: Twelve women without ovarian function. INTERVENTIONS: [1] In a control cycle, patients received 4 or 8 mg of oral E2 and vaginal ultrasound (US) daily until endometrial thickness > or = 6 mm with a triple-line pattern (favorable endometrium) was seen. Progesterone (P) in oil, 100 mg/d, was then added. [2] An endometrial biopsy was performed on day 7 of P therapy. [3] In a treatment cycle, US monitoring of endometrial development during estrogen (E) administration was used; and ET was performed on the 3rd day of P therapy. RESULTS: In the control cycle, 8 mg/d or 4 mg/d of micronized E2 resulted in favorable endometrium development in all patients in a mean time of 5 and 7 days, respectively. After P treatment, only 1 of 12 endometrial biopsies was in phase. In the treatment cycles, the overall clinical pregnancy rate (PR) was 42%. In those patients with a favorable endometrium in the E replacement phase, before addition of P, the PR was 62.5%. All of the pregnant patients but only 42.8% of the nonpregnant patients had a favorable endometrium on US before the addition of P. CONCLUSION: An endometrium that is favorable for implantation can result from the use of a simple fixed dose of E2, with higher doses achieving favorable endometrial development in shorter time. Vaginal sonography of endometrial development before P administration is more accurate than endometrial biopsy in predicting a successful donor egg cycle. Endometrial preparation in donor oocyte programs can be simplified by the use of vaginal US monitoring.

Endometrium↗

PubMed1992

Growth suppression mediated by transfection of p53 in Hut292DM human lung cancer cells expressing endogenous wild-type p53 protein.

This study was undertaken to analyze the effect of wild-type p53 transfection on the growth potential of a human lung cancer cell line Hut292DM expressing endogenous wild-type p53. Transfection efficiencies obtained with either the wild-type or a mutant p53 complementary DNA revealed a significant decrease in the number of colonies obtained with the wild-type p53 as compared to the mutant p53 complementary DNA (27%) or control vector DNA only (20%), suggesting that wild-type p53 inhibited the growth of Hut292DM cells. A series of wild-type and mutant p53 transfection clones were then analyzed for the presence and expression of the exogenous p53 gene. Polymerase chain reaction amplification revealed that 98% of mutant p53 transfection clones analyzed contained the exogenous p53 gene as opposed to 47% for wild-type p53 clones. The majority of mutant p53 clones expressed high levels of exogenous p53 mRNA and protein as analyzed by Northern and Western blots, respectively. In contrast, all wild-type p53 clones analyzed failed to express exogenous p53 mRNA transcript or protein of a normal size. Aberrant-size p53 mRNA was detected in two wild-type p53 clones (X833.W2 and W18), and Western blot analysis revealed that these clones expressed truncated p53 proteins (M(r) 45,000 and 33,000 respectively). No difference in proliferation rates in vitro or in tumorigenic potential in nude mice were observed between mutant p53 clones or control cell lines. In contrast, a wild-type p53 clone (X833.W2) exhibited a significantly reduced tumorigenic potential in nude mice, whereas its in vitro proliferation rate was comparable to parental Hut292DM cells. The data indicate that exogenous expression of wild-type p53 is incompatible with Hut292DM lung cancer cell proliferation in vitro and suggest that p53-mediated growth control in vitro and in vivo may be dissociated and exerted by separate domains of the p53 protein.

Animals↗