SEARCH · PubMed Health

Results for “PAM”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources

PubMed1994

Use of the potential acuity meter and laser interferometer to predict visual acuity after macular hole surgery.

PURPOSE: As reported anatomic success rates for macular hole surgery increase, a method of accurately predicting postoperative visual acuity has increased clinical utility. METHODS: A series of 18 patients undergoing vitrectomy for idiopathic macular holes was evaluated prospectively for best refracted preoperative visual acuity, potential acuity meter (PAM) reading, and laser interferometer (LI) reading. Best refracted visual acuity after surgery was recorded and analyzed to assess the predictive value of the PAM and LI readings. RESULTS: The LI correctly predicted the final visual result in 6 of the 10 patients who achieved a final visual acuity of 20/50 or better (P = < 0.011). The PAM did not accurately predict postoperative visual acuity for any of the eyes with a final visual acuity of 20/50 or better. Both correctly predicted outcome in the 7 patients with final visual acuity worse than 20/50. The LI prediction was within 2 lines of final visual acuity in 12 (70%) of 17 anatomically successful cases, and the PAM was within 2 lines of final visual acuity in 11 (64%) of 17 cases. CONCLUSION: Both the LI and PAM were modestly accurate in predicting final visual acuity after macular hole surgery, but the LI was more accurate in predicting a visual acuity of 20/50 or better.

Aged↗

PubMed1989

Isolated limb perfusion for stage I melanoma of the extremity: a comparison of melphalan and dacarbazine (DTIC).

Isolated limb perfusion (ILP) for melanoma of the extremity was first used clinically more than 30 years ago. Although ILP with chemotherapeutic agents has become routine practice in many oncologic centers, few studies have evaluated the therapeutic efficacy of particular agents. Two consecutive groups of 100 patients with stage I extremity melanoma of 1.5 mm thickness or greater were treated by ILP with either melphalan (L-PAM) or dacarbazine (DTIC). Demographics, clinical and pathologic stage, disease site, and complications were similar in both groups. No significant difference in the overall incidence of recurrent disease at two years was found between patients treated with either DTIC or L-PAM (22% vs 16%, respectively; P = .28). Patients who had perfusion with L-PAM, however, had a lower incidence of in-transit metastasis and recurrence at the scar than those having DTIC therapy (4% vs 12%, P = .06) at two years of follow-up. This preliminary report suggests that L-PAM may be more effective than DTIC in controlling scar recurrences and in-transit metastasis. Continued follow-up of this series of patients, with further analysis of patterns of recurrence and disease-free and overall survival at five years, will be necessary to better define the relative efficacy of L-PAM and DTIC in isolated limb perfusion.

Adult↗

PubMed1995

Tetramodality treatment of human melanoma in vitro.

We evaluated the in vitro cytotoxic effects of combined human tumour necrosis factor alpha (TNF), human interferon gamma (IFN-gamma), melphalan (L-PAM) and hyperthermia (HTX) on human melanoma cell lines using the crystal violet assay. HTX (40 degrees C, 1 h) alone had no effect. The responses of the cell lines to TNF were in the rank order of 939 cells > 987 > 284 > C8161 > 852 > A2058 approximately 0, and all displayed shallow dose-response curves; no significant thermal enhancement of TNF cytotoxicity was apparent with this heat dose. All cell lines were sensitive to L-PAM, with 284 cells being the most sensitive; HTX caused only slightly increased sensitization to L-PAM. The combination of TNF and L-PAM resulted in generally subadditive or additive cytotoxicity, with or without HTX. The response to IFN-gamma alone was heterogeneous; the 939, 284 and 852 cell lines were sensitive to a dose as low as 20 ng/ml, whereas the 987 line was resistant to 2.0 micrograms/ml, even with HTX. IFN-gamma enhanced the response to TNF only of the TNF-resistant A2058 cell line, but there was no enhancement of the response to L-PAM for any line. Thus, this tetramodality combination achieved generally subadditive or additive cytoxicity in vitro.

Cell Survival↗

PubMed1987

Lymphokine mediated production of an epidermal cell proliferation factor by cultured murine bone marrow cells.

The effect of cultured bone marrow cell supernatant (BMS) was studied on the proliferative response of cells of the transformed murine epidermal cell line Pam 212. Elevated DNA synthesis was found in Pam 212 cells cultured with BMS from bone marrow cells grown in spleen cell conditioned medium with concanavalin A (ConA). Pam cell proliferative activity was related to the histamine content in the culture supernatant. Neither spleen cell conditioned medium with IL1, IL2, or IL3 activity, nor ConA alone, showed any effect on Pam cell growth. A soluble mediator from the cultured bone marrow cells with mast cell characteristics was thought to be responsible for the stimulation of Pam cell growth, and Con A appeared to be a prerequisite for generation of this factor by the bone marrow cells.

Animals↗

PubMed2006

Oral administration of pulverized Konjac glucomannan prevents the increase of plasma immunoglobulin E and immunoglobulin G levels induced by the injection of syngeneic keratinocyte extracts in BALB/c mice.

BACKGROUND: Immunoglobulin (Ig) E plays a key role in the pathogenesis of atopic diseases, such as asthma, atopic dermatitis and allergic rhinitis. Oral administration of pulverized Konjac glucomannan (PKGM) has recently been demonstrated to prevent both plasma IgE elevation and developing dermatitis in NC/Nga mice, a model of atopic dermatitis. OBJECTIVE: To clarify the direct effect of PKGM on the increase of plasma IgE, we employed the system of BALB/c mouse that increases IgE level without developing dermatitis in response to continuous injection of the extract of syngeneic keratinocytes, PAM 212 cells (PAM extract). METHODS: Three weeks after the start of feeding with either control or PKGM diet, mice were injected subcutaneously with PAM extract bi-weekly for 10 weeks. The levels of plasma Igs were measured by enzyme-linked immunosorbent assay every 2 weeks after the injection. The levels of epsilon germline transcription and the amounts of mRNA for IL-4, IFN-gamma, GATA-3 and T bet gene in the spleen were evaluated by real-time RT-PCR at the end of the experiment. RESULTS: On the one hand, PKGM prevented the increase of plasma IgE and IgG (IgG1, IgG2b) induced by PAM extract, and on the other hand, it enhanced the levels of plasma IgG3. However, it did not affect the level of plasma IgM. PKGM also reduced the levels of plasma ovalbumin (OVA)-specific IgE in OVA-sensitized mice. Moreover, PKGM attenuated the induction of epsilon germline transcription and expression levels of mRNA for IL-4, IFN-gamma and GATA-3 in the spleen of PAM extract-injected mice. PKGM also attenuated the induction of epsilon germline transcription and mRNA for IFN-gamma and T bet in the spleen of phosphate-buffered saline-injected control mice. CONCLUSIONS: These results suggested that oral administration of PKGM prevents the elevation of plasma IgE by suppressing IgE class switching in B cells and/or the commitment development of naive lymphocytes to both T-helper type 1 (Th1) and Th2.

Administration, Oral↗

PubMed1993

Identification and characterization of an amidating enzyme in ovine heart.

1. Levels of peptidylglycine alpha-amidating mono-oxygenase (PAM) activity were examined in sheep and rat heart. This enzyme is responsible for alpha-amidation of a large number of peptide hormones, a modification essential for the bioactivity of these peptides. 2. PAM activity was measured in membrane and soluble fractions of atrial and ventricular homogenates by monitoring the amidation of iodinated synthetic substrate ([125I]-Ac-Tyr-Val-Gly). 3. PAM activity in both species resided almost exclusively in the atria rather than the ventricles, and similar levels of activity were found in left and right atria. Membrane-associated activity was 50-to 100-fold greater than soluble activity in the sheep, yet was only five- to 10-fold greater in the rat, indicating a larger proportion of soluble enzyme in the rat atrium. 4. Similar apparent Km values were found for atrial membrane-associated activity in both species (15.6 and 17.4 mumol/L for rat right and left atria, 16.7 and 15.6 mumol/L for sheep right and left atria); however, the maximum velocity (Vmax) levels were higher in the rat (40.5 and 43.9 pmol/micrograms per h vs 12.8 and 15.1 pmol/micrograms per h). 5. Because expression of many peptides and processing enzymes can be regulated by steroid hormones, the possible effects of chronic glucocorticoid administration (1 mg dexamethasone i.m. twice daily for 10 days) on PAM levels were tested in four sheep, with four sheep receiving saline only as controls. There was no discernible effect of dexamethasone on either the distribution or the kinetics of PAM activity in the sheep heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed2006

Tetracycline, metronidazole and amoxicillin-metronidazole combinations in proton pump inhibitor-based triple therapies are equally effective as alternative therapies against Helicobacter pylori infection.

BACKGROUND: A proton pump inhibitor (PPI)-based triple therapy with clarithromycin (CAM) and amoxicillin (AMPC) is now a standard regimen for Helicobacter pylori (HP) eradication in Japan. However, the CAM-resistant rate has increased recently and alternative therapies are sorely needed. Therefore the aim of the present study was to evaluate the effectiveness and safety of the PPI-tetracycline (TC)-metronidazole (MNZ) regimen (the PTM regimen) as an alternative therapy in comparison with the PPI-AMPC-MNZ (PAM) regimen. METHODS: Sixty-four HP-positive patients visiting the HP-eradication clinic in Tokai University Hospital from July 1998 to March 2003 were treated with either PTM or PAM as alternative therapies. The HP eradication was assessed by urea breath test (UBT), HP stool antigen test, or HP culture method more than 2 months after completion of the treatments. The drug resistances against CAM, AMPC, TC, and MNZ were assessed by the agar dilution method. RESULTS: Fifty-six patients (26 PTM and 30 PAM) completed medication and evaluation of the eradication. The eradication rates of PTM were 82.8% (24/29) and 92.3% (24/26), while those of PAM were 74.3% (26/35) and 89.7% (26/29) by intention-to-treat and per-protocol analysis, respectively. The differences between the regimens were not statistically significant. There were no severe adverse effects observed in either of the regimens. The drug-resistance analyses showed 15 CAM- and one MNZ-resistant cases but no TC or AMPC resistance in the available 25 samples. CONCLUSION: The PTM and PAM regimens were equally effective and safe as alternative HP eradication therapies. And PTM would be particularly useful in penicillin allergy cases.

Amoxicillin↗

PubMed1993

Neurosecretory vesicles contain soluble and membrane-associated monofunctional and bifunctional peptidylglycine alpha-amidating monooxygenase proteins.

Peptidylglycine alpha-amidating monooxygenase (PAM) catalyzes the COOH-terminal amidation of neuropeptides in a reaction requiring the sequential action of two enzymes contained within this bifunctional protein. The CNS contains primarily transcripts encoding rPAM-1 and rPAM-2, integral membrane proteins differing by the presence or absence of a noncatalytic domain separating the two enzymes. Subcellular fractionation of adult rat hypothalamus and hippocampus demonstrated the localization of both enzymatic activities to fractions enriched in neurosecretory vesicles. Upon separation of the soluble contents from the membranes of neurosecretory vesicles, 30-40% of both enzymatic activities was recovered in the soluble fraction. Over 40% of both enzymatic activities remained membrane-associated following removal of peripheral membrane proteins. Antisera specific to different regions of PAM were used to identify intact rPAM-1 and rPAM-2, a monofunctional integral membrane peptidyl-alpha-hydroxy-glycine alpha-amidating lyase protein generated from rPAM-1, and a noncatalytic COOH-terminal fragment as the major PAM proteins in carbonate-washed membranes. Endoproteolytic processing generated large amounts of soluble, monofunctional forms of both enzymes from rPAM-1 and smaller amounts of a soluble, bifunctional PAM protein from rPAM-2. A significant amount of both monofunctional enzymes lacking the transmembrane domain was tightly associated with membranes. Whereas soluble mono- and bifunctional enzymes may be released upon exocytosis of neurosecretory vesicles, membrane-associated PAM proteins may remain on the cell surface or be internalized.

Amidine-Lyases↗

PubMed1985

The sustained release of pyrimethamine base or pyrimethamine pamoate from a biodegradable injectable depot preparation in mice.

The pharmacokinetics and mass fate in mice, of pyrimethamine (425 mg kg-1 s.o.) administered subcutaneously either as the base (BASE) or the pamoate salt (PAM) in an injectable oil mixture (benzyl benzoate-peanut oil 50:50 v/v) have been evaluated. Maximum measured plasma pyrimethamine levels after BASE were attained within 24 h, and were twice as high as after PAM. 25% of animals dosed with BASE died; among the survivors plasma drug levels fell rapidly below the minimum inhibitory concentration (MIC) for Plasmodium berghei (100-200 ng ml-1) by 5 weeks. In contrast, no mice dosed with PAM died and plasma levels were sustained above the MIC for 13 weeks, drugs still being detectable in plasma after four months. Overall, there was no significant difference between areas under the curve from zero time to the time of the final sampling of pyrimethamine following PAM or BASE. The rapid initial elimination of 14C-radioactivity (2.64 +/- 0.47% dose day-1 over 4 weeks) seen after dosage with [14C]BASE reflected the plasma disposition of pyrimethamine in the mice dosed with BASE. 90% of the excreted 14C was eliminated by one month by which time less than 1% (0.03 +/- 0.02%) of the [14C]BASE was recovered from the injection site. Both BASE and [14C]BASE studies suggest that exhaustion of this preparation occurred by 7 weeks. Excretion of 14C-radioactivity after [14C]PAM was gradual and sustained with a low mean daily rate, that was maintained throughout the study i.e. 1.21 +/- 0.17% day-1 (4 weeks), 0.88 +/- 0.28% day-1 (8 weeks), 0.5 +/- 0.31% day-1 (12 weeks), 0.42 +/- 0.27% day-1 (16 weeks).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2026

Efficient CRISPR/Cas-SF01 genome editing tools with high editing efficiency in allotetraploid oilseed rape.

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-Cas9 has been widely utilized for plant genome editing, but the protospacer adjacent motif (PAM) requirement limits its editing scope. CRISPR/Cas12i3 belongs to the type-VI Cas system that has gained extensive attention due to its smaller size and less restricted canonical TTN PAM sequence. In this study, we explored the newly developed Cas-SF01 system (Cas12i3 variant) for genome editing in oilseed rape. We established an efficient protoplast transformation system in oilseed rape to compare editing efficiency between Cas-SF01 and Cas9. Cas-SF01 shows cleavage activities at the tested 5'-TTN-3' PAM sites with editing outcomes sharing considerable similarities with the CRISPR-Cas9 system in protoplast. Cas-SF01 also induces high efficiency mutagenesis for multiple target sites in stable transformed oilseed rape lines, generating mutants with multilocular silique and male sterile phenotypes. Furthermore, Cas-SF01-derived cytosine base editors (CBEs) were developed to produce targeted C-to-T base edits. Compared to SpCas9, Cas-SF01 has an expanded PAM range and effectively recognizes TTN PAMs, which has substantially broadened the scope of editable sites within the rapeseed genome. No mutations were identified at the putative off-target sites among the edited plants. This study developed a robust, first-of-its-kind Cas12 system in the allotetraploid Brassica napus, expanding the scope of editing and enriching genome-editing toolkits for biological research and genetic improvement.

Brassica napus↗

PubMed2002

Electrophysiologically distinct smooth muscle cell subtypes in rat conduit and resistance pulmonary arteries.

Pulmonary arteries (PAs), particularly those of the rat, demonstrate a prominent voltage-gated K+ (Kv) current (I(Kv)), which plays an important role in the regulation of the resting potential. No detailed characterization of electrophysiological and pharmacological properties of I(Kv), particularly in resistance PA myocytes (PAMs), has been performed. The aim of the present study was therefore to compare I(Kv) in rat conduit and resistance PAMs using the standard patch clamp technique. We found that 67% of conduit PAMs demonstrated a large, rapidly activating I(Kv) which was potently blocked by 4-aminopyridine (4-AP; IC50, 232 microM), but was almost insensitive to TEA (18% block at 20 mM). Thirty-three percent of cells exhibited a smaller, more slowly activating I(Kv) which was TEA sensitive (IC50, 2.6 mM) but relatively insensitive to 4-AP (37% block at 20 mM). These currents (termed I(Kv1) and I(Kv2), respectively) inactivated over different ranges of potential (V(0.5) = -20.2 vs. -39.1 mV, respectively). All resistance PAMs demonstrated a large, rapidly activating and TEA-insensitive K+ current resembling I(Kv1) (termed I(KvR)), but differing significantly from it with respect to 4-AP sensitivity (IC50, 352 microM), activation rate, and inactivation potential range (V(0.5), -27.4 mV). Thus, cells from conduit PAMs fall into two populations with respect to functional I(Kv) expression, while resistance arteries uniformly demonstrate a third type of I(Kv). Comparison of the properties of the native I(Kv) with those of cloned Kv channel currents suggest that I(Kv1) and I(KvR) are likely to be mediated by Kv1.5-containing homo/heteromultimers, while I(Kv2) involves a Kv2.1 alpha-subunit.

Animals↗

PubMed1988

Intergeneric and intrageneric conjugal transfer of plasmid-encoded antibiotic resistance determinants in Leuconostoc spp.

Transfer of the broad-host-range resistance plasmids pIP501 and pAM beta 1 from Streptococcus faecalis to Leuconostoc dextranicum and Leuconostoc cremoris occurred between cells that were immobilized on nitrocellulose filters in the presence of DNase. Transfer of pIP501 to Leuconostoc spp. also occurred when Streptococcus sanguis and Streptococcus lactis were used as donors. In addition, transfer of pIP501 and pAM beta 1 was observed from L. cremoris and L. dextranicum transconjugants to S. sanguis and S. faecalis. Expression of the pAM beta 1 erythromycin and pIP501 erythromycin and chloramphenicol resistance determinants was essentially equivalent in donors and transconjugants. Frequencies of transfer generally ranged from 10(-4) to 10(-7) transconjugants per input donor cell. Intrageneric transfer of pIP501 and pAM beta 1 occurred between L. cremoris and L. dextranicum strains in the same approximate range. These data further extend the host range of pIP501 and pAM beta 1 and demonstrate another example of gene transfer in the genus Leuconostoc.

Chloramphenicol↗

PubMed2004

Increased production of proinflammatory cytokines following infection with porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae.

Induction of the proinflammatory cytokines interleukin-1 (IL-1) (alpha and beta), IL-6, IL-8, IL-10, IL-12, and tumor necrosis factor alpha (TNF-alpha) in pulmonary alveolar macrophages (PAMs) was assessed following experimental infection with porcine reproductive and respiratory syndrome virus (PRRSV) and/or Mycoplasma hyopneumoniae by using in vivo and in vitro models. The in vivo model consisted of pigs infected with PRRSV and/or M. hyopneumoniae and necropsied at 10, 28, or 42 days postinfection. Pigs infected with both pathogens had a greater percentage of macroscopic lung lesions, increased clinical disease, and slower viral clearance than pigs infected with either pathogen alone. The pigs infected with both PRRSV and M. hyopneumoniae had significantly increased levels of mRNA for many proinflammatory cytokines in PAMs collected by bronchoalveolar lavage (BAL) at all necropsy dates compared to those in uninfected control pigs. Increased levels of IL-1beta, IL-8, IL-10, and TNF-alpha proteins in BAL fluid, as measured by enzyme-linked immunosorbent assay, confirmed the increased cytokine induction induced by the pathogens. An in vitro model consisted of M. hyopneumoniae-inoculated tracheal ring explants cultured with PRRSV-infected PAMs. PAMs were harvested at 6 or 15 h postinfection with either or both pathogens. The in vitro study detected increased IL-10 and IL-12 mRNA levels in PAMs infected with PRRSV at all time periods. In addition, IL-10 protein levels were significantly elevated in the culture supernatants in the presence of M. hyopneumoniae-inoculated tracheal ring explants. The increased production of proinflammatory cytokines in vivo and in vitro associated with concurrent M. hyopneumoniae and PRRSV infection may play a role in the increased rates of pneumonia associated with PRRSV infection. The increased levels of IL-10 may be a possible mechanism that PRRSV and M. hyopneumoniae use to exacerbate the severity and duration of pneumonia induced by PRRSV and modulate the respiratory immune response.

Animals↗

PubMed2006

Chlamydia pneumoniae--induced macrophage foam cell formation is mediated by Toll-like receptor 2.

Chlamydia pneumoniae induces macrophage foam cell formation, a hallmark of early atherosclerosis, in the presence of low-density lipoprotein (LDL). This study examined the role that Toll-like receptor 2 (TLR2) and TLR4 may play in pathogen-induced foam cell formation. Murine macrophage RAW 264.7 cells either infected with C. pneumoniae or treated with the TLR4 ligand E. coli lipopolysaccharide (LPS) or the TLR2 ligand Pam(3)-Cys-Ala-Gly-OH (Pam) became Oil Red O-stained foam cells and showed increased cholesteryl ester (CE) content when cocultured with LDL. In macrophages from TLR2(-/-) mice, foam cells were induced by Escherichia coli LPS but not by C. pneumoniae or Pam. Conversely, C. pneumoniae or Pam, but not E. coli LPS, induced foam cells in the TLR4-deficient GG2EE macrophage cell line, suggesting that C. pneumoniae elicits foam cell formation predominantly via TLR2. Enhancing cholesterol efflux using the liver X receptor (LXR) agonist GW3965 significantly decreased the CE content of cells exposed to each of the three TLR ligands (C. pneumoniae, Pam, and E. coli LPS). Overall, our results suggest that activation of the LXR signaling pathway may affect potentially atherogenic processes modulated by the TLR ligands.

Animals↗

PubMed1976

Scrapie in vitro: agent replication and reduced cell yield.

Exposure of PAM cells, a spontaneously transformed mouse cell line, to brain homogenates from mice infected with scrapie caused a relative decrease in total cell yield, which persisted from passage 2 or 3 to passage 18 after treatment. The effect was elicited by each of the eight independent scrapie isolates tested. Lysates prepared from cultures 16 passages after treatment with scrapie caused the decrease when applied to fresh PAM cultures. Mice inoculated with passage 14 and 18 lysates developed a reduced percentage of polymorphonuclear neutrophils by 5 weeks and scrapie disease by 6 to 9 months after inoculation. Based on the total dilution from treatment of the PAM cultures with scrapie material to the preparation of the lysates, we conclude that the agent(s) responsible for the reduced PAM cell yield, the decreased percentage of polymorphonuclear neutrophils, and the induction of scrapie disease had replicated in the PAM cells. By filtration, the diameter of the agent causing the reduction in cell yield was estimated to be between 25 and 50 nm.

Animals↗

PubMed2003

Expression of variant surface antigens by Plasmodium falciparum parasites in the peripheral blood of clinically immune pregnant women indicates ongoing placental infection.

Placenta-sequestered Plasmodium falciparum parasites that cause pregnancy-associated malaria (PAM) in otherwise clinically immune women express distinct variant surface antigens (VSA(PAM)) not expressed by parasites in nonpregnant individuals. We report here that parasites from the peripheral blood of clinically immune pregnant women also express VSA(PAM), making them a convenient source of VSA(PAM) expressors for PAM vaccine research.

Animals↗

PubMed2002

Involvement of the matrix protein in attachment of porcine reproductive and respiratory syndrome virus to a heparinlike receptor on porcine alveolar macrophages.

The porcine reproductive and respiratory syndrome virus (PRRSV) has a very restricted tropism for well-differentiated cells of the monocyte-macrophage lineage, which is probably determined by specific receptors on these cells. In this study, the importance of heparinlike molecules on porcine alveolar macrophages (PAM) for PRRSV infection was determined. Heparin interacted with the virus and reduced infection of PAM up to 92 or 88% for the American and European types of PRRSV, respectively. Other glycosaminoglycans, similar to heparin, had no significant effect on infection while heparinase treatment of PAM resulted in a significant reduction of the infection. Analysis of infection kinetics showed that PRRSV attachment to heparan sulfate occurs early in infection. A heparin-sensitive binding step was observed which converted completely into a heparin-resistant binding after 120 min at 4 degrees C. Using heparin-affinity chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), it was observed that the structural matrix (M) and nucleocapsid (N) proteins attached to heparin. Nonreducing SDS-PAGE revealed that M bound to heparin mainly as a complex with glycoprotein GP(5) and that the N protein bound to heparin as a homodimer. GP(3), which was identified as a minor structural protein of European types of PRRSV, did not bind to heparin. Since the N protein is not exposed on the virion surface, it was concluded that the structural M protein and the M-GP(5) complex contribute to PRRSV attachment on a heparinlike receptor on PAM. This is the first report that identifies a PRRSV ligand for a cell surface heparinlike receptor on PAM.

Animals↗

PubMed1996

Cell growth and p53 expression in primary acquired melanosis and conjunctival melanoma.

AIMS: To evaluate cell growth and the pattern of p53 suppressor gene expression in atypical primary acquired melanosis (PAM) and in recurrent conjunctival melanoma. METHODS: Eighteen specimens of PAM with atypia and 24 specimens, comprising early and late lesions, from 12 patients with conjunctival melanoma were stained for the proliferating cell nuclear antigen using the PC10 antibody, and for the p53 gene product using the BP53-12-1, 1801 and DO7 clones. The immunoreactive cells were counted manually and the data evaluated statistically. RESULTS: Seven of nine PAM specimens progressing to melanoma expressed PC10. None of these lesions expressed the p53 gene product. The number of proliferating cells was higher in the late than in the early lesions of conjunctival melanoma. Four of the 12 recurrent melanomas displayed focal, but minimal, p53 expression. The proliferating cell count in the p53 positive tumours was very similar to that of the p53 negative conjunctival melanomas. CONCLUSION: Examination of the expression of proliferating cells in atypical PAM may be used as an adjunct to predict which lesions will progress to melanoma. The increase in the number of proliferating cells over time in recurrent conjunctival melanomas probably reflects more aggressive behaviour and may be used to monitor recurrence. The absence of p53 expression in PAM and minimal staining of conjunctival melanomas did not correlate with cell growth, suggesting that alterations in the p53 tumour suppressor gene are uncommon and late events in conjunctival melanoma, and that p53 expression is unlikely to be a useful prognostic indicator.

Adult↗