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PubMed1991

Effectiveness of oximes 2-PAM and HI-6 in recovery of muscle function depressed by organophosphate agents in the rat hemidiaphragm: an in vitro study.

Phrenic nerve diaphragm muscles of young adult rats were used to study the ability of the oximes 2-PAM and HI-6 to recover muscle function depressed by organophosphate (OP) agents. The single twitch of diaphragm muscles which were exposed to soman (0.2 microM) recovered after washing with saline for 3 hr, but the muscles pretreated with sarin (0.4 microM), VX (0.2 microM), or tabun (0.4 microM) showed only partial recovery. In addition, after 3 hr washing, the muscles pretreated with soman as well as with tabun did not recover the tetanus sustaining ability (TSA), yet complete recovery was observed with muscles pretreated with sarin and VX. These results indicate that the OPs have different effects on muscle contractile properties and that VX- and sarin-pretreated muscles recover equally well after wash with physiological solution. The recovery of twitch tension of diaphragm muscles by 2-PAM and HI-6 was similar to that achieved by washing with saline for 3 hr for sarin- and soman-exposed muscles. The most remarkable differences were seen in the recovery of TSA. Both 2-PAM and HI-6 recovered the TSA of muscles that were pretreated with sarin and VX. Although 2-PAM recovered the TSA after tabun pretreatment, HI-6 had no discernible effect. On the other hand, HI-6 recovered the TSA of soman-pretreated muscles but 2-PAM did not. The effectiveness of muscle function recovery was not related to the oximes' ability to reactivate AChE, thus indicating that the recovery of muscle contractility may be attributed to a direct effect of these compounds on the muscle.

Animals↗

PubMed1988

Characterization of a pAM beta 1 deletion derivative isolated from Lactobacillus casei after conjugation.

Streptococcal plasmid pAM beta 1 was conjugally transferred from Streptococcus lactis KB953 (a transformant of pAM beta 1) into Lactobacillus casei 239. A unique transconjugant, L. casei C2, was found to contain a small (11.1 kilobase pair) plasmid, pLY201, which was derived by a deletion event from pAM beta 1. Restriction analysis revealed that pLY201 was missing approximately 58% of the original pAM beta 1 genome, and contained 5 single restriction sites for AvaI, EcoRI, PvuII, HpaI and KpnI. Physical analyses revealed that the stability and copy number of pLY201 were elevated compared with those of pAM beta 1 in L. casei. In addition, pLY201 was no longer transferable by conjugation.

Conjugation, Genetic↗

PubMed1994

A comparison of the efficacy of HI6 and 2-PAM against soman, tabun, sarin, and VX in the rabbit.

This study compared the efficacy of HI6 and 2-PAM against nerve agent (soman, tabun, sarin, and VX)-induced lethality in the atropinesterase-free rabbits pretreated with vehicle (controls) or pyridostigmine. Treatment was administered at signs or 2 min after agent challenge and consisted of oxime (100 mumol/kg) + atropine (13 mg/kg) (alone or together with diazepam). Twenty-four-h LD50 values were calculated for soman- and tabun-intoxicated animals, whereas 24-h survival was noted in animals given 10 LD50s of sarin or VX. In pyridostigmine and control rabbits intoxicated with soman and treated with oxime + atropine (alone or together with diazepam), HI6 was 3-5 times more effective than 2-PAM. In contrast, HI6 was less effective than 2-PAM against tabun poisoning. In pyridostigmine-pretreated animals exposed to tabun, efficacy was increased more than 3-fold when compare to tabun-challenged animals treated with atropine + HI6 alone. Both oximes were highly effective against sarin and VX. These findings suggest that HI6 could replace 2-PAM as therapy for nerve agent poisoning, because it is superior to 2-PAM against soman, and when used in pyridostigmine-pretreated animals, it affords excellent protection against all four nerve agents when used in combination with atropine (alone or together with diazepam) therapy.

Animals↗

PubMed2005

The treatment of primary acquired melanosis (PAM) with atypia by topical Mitomycin C.

PURPOSE: To report our results of 12 consecutive patients with conjunctival primary acquired melanosis (PAM) with atypia who were treated by topical Mitomycin C (MMC). DESIGN: Retrospective interventional consecutive case series. METHODS: Twelve patients with PAM with atypia in one of their eyes who were treated by topical chemotherapy with MMC were included in this case study. Eyes with histologically proven PAM with atypia were treated by two to five courses of 0.04% (0.4 mg/ml) MMC four times a day. Each course lasted 2 continuous weeks. Follow-up was conducted on patients for control of local disease, side effects, and visual acuity in the treated eye. RESULTS: In all patients, there was complete or partial response to treatment. In four patients, the pigmentation disappeared, whereas in eight patients, some remnants of the pigmentation remained. In seven of these eight patients, the remnants of the pigmentation were stable during the follow-up period of 4 months to 9 years, whereas one in whom re-growth of the PAM was noticed was successfully treated again by topical MMC. No patients lost visual acuity at the end of the follow-up. All side effects of the local chemotherapy were resolved after cessation of the treatment. CONCLUSIONS: Topical MMC chemotherapy is a good alternative to surgical excision and cryotherapy in treating conjunctival PAM with atypia.

Administration, Topical↗

PubMed1997

Buthionine sulphoximine alone and in combination with melphalan (L-PAM) is highly cytotoxic for human neuroblastoma cell lines.

Buthionine sulphoximine (BSO) selectively inhibits glutathione (GSH) synthesis and may enhance the antineuroblastoma activity of melphalan (L-PAM). We determined the cytotoxicity of BSO (dose range 0-1000 microM) alone and in combination with L-PAM (dose range 0-0 microM) in a panel of 18 human neuroblastoma cell lines. BSO alone was highly cytotoxic with 16/18 neuroblastoma cell lines having IC90 values (range 2.1- > 1000 microM) below the clinically achievable steady-state plasma level of 500 microM BSO. Maximal cell killing correlated with GSH levels decreased to less than 10% baseline, and was partially reversed by the addition of exogenous anti-oxidants (GSH, vitamin E and ascorbate). Fluorocytometric analysis of DNA fragments by the Tunnel method detected 92% of a BSO sensitive cell line in apoptosis after a 48 h exposure to 500 microM BSO. The combination of L-PAM and BSO synergistically enhanced the cell killing of L-PAM alone by > 1-3 logs (combination index < 1). We conclude that BSO has significant single-agent cytotoxicity against neuroblastoma and enhances cell killing when combined with L-PAM.

Antineoplastic Agents↗

PubMed2000

Methodological and biological aspects to be considered in acetylcholinesterase reactivation assays using 2-PAM.

Kinetic and toxicological characteristics of fish (Odontesthes argentinensis) and crab (Callinectes sapidus) cholinesterases as well as methodological conditions to perform reactivation assays using pyridine 2-aldoxime (2-PAM) were established. According to kinetic and eserine sensitivity data, both cholinesterases can be considered as acetylcholinesterases. The concentration of eserine that inhibited 50% of enzyme activity (IC(50)) was estimated as 15.9x10(-8) and 4.6x10(-8) M for crab and fish, respectively. For purified eel acetylcholinesterase (V-S type), it was estimated as 4.2x10(-8) M. 2-PAM showed both to increase non-enzymatic hydrolysis of acetylthiocholine iodide and to inhibit activity of the acetylcholinesterases tested. The IC(50) of 2-PAM for crab acetylcholinesterase (8.2x10(-4) M) was significantly higher than that from O. argentinensis (2.5x10(-4) M) or eel (2.0x10(-4) M) acetylcholinesterase. Enzyme inhibition induced by 2-PAM showed to mask subtle inhibition due to malathion, suggesting that a previous characterization of 2-PAM inhibition must be done before its use in reactivation assays.

Journal Article↗

PubMed2001

A dual path programmable array microscope (PAM): simultaneous acquisition of conjugate and non-conjugate images.

A programmable array microscope (PAM) incorporates a spatial light modulator (SLM) placed in the primary image plane of a widefield microscope, where it is used to define patterns of illumination and/or detection. We describe the characteristics of a special type of PAM collecting two images simultaneously. The conjugate image (Ic) is formed by light originating from the object plane and returning along the optical path of the illumination light. The non-conjugate image (Inc) receives light from only those regions of the SLM that are not used for illuminating the sample. The dual-signal PAM provides much more time-efficient excitation than the confocal laser scanning microscope (CLSM) and greater utilization of the available emission light. It has superior noise characteristics in comparison to single-sided instruments. The axial responses of the system under a variety of conditions were measured and the behaviour of the novel Inc image characterized. As in systems in which only Ic images are collected (Nipkow-disc microscopes, and previously characterized PAMs), the axial response to thin fluorescent films showed a sharpening of the axial response as the unit cell of the repetitive patterns decreased in size. The dual-signal PAM can be adapted to a wide range of data analysis and collection strategies. We investigated systematically the effects of patterns and unit cell dimensions on the axial response. Sufficiently sparse patterns lead to an Ic image formed by the superposition of the many parallel beams, each of which is equivalent to the single scanning spot of a CLSM. The sectioning capabilities of the system, as given by its axial responses, were similar for a given scan pattern and for processed pseudorandom sequence (PRS) scans with the same size of the unit cell. For the PRS scans, optical sectioning was achieved by a subtraction of an Inc image or, alternatively, a scaled widefield image from the Ic image. Based on the comparative noise levels of the two methods, the non-conjugate subtraction was significantly superior. A point spread function for Ic and Inc was simulated and properties of the optical transfer functions (OTFs) were compared. Simulations of the OTF in non-conjugate imaging did not suffer from the missing cone problem, enabling a high quality deconvolution of the non-conjugate side alone. We also investigated the properties of images obtained by subjecting the Ic and Inc data to a combined maximum likelihood deconvolution.

Animals↗

PubMed1975

L-Phenylalanine mustard (L-PAM) in the management of primary breast cancer. A report of early findings.

Prolonged l-phenylalanine mustard (L-PAM) administration as an adjuvant to mastectomy in the management of patients with primary breast cancer and pathologically positive axillary nodes was evaluated by a prospective, randomized, clinical trial. Treatment failures occurred in 22 per cent of 108 patients receiving placebo and 9.7 per cent of 103 women given L-PAM (p = 0.01). A statistically significant difference (p = 0.02) existed in favor of L-PAM relative to disease-free interval. In premenopausal women, the difference with respect to disease-free interval of treated and control groups was highly significant (p = 0.008). A treatment failure occurred in 30 per cent of premenopausal patients receiving placebo and 3 per cent of those treated with L-PAM (p = 0.008). Whereas a similar trend was observed in postmenopausal patients, the difference is not statistically significant. Thus, L-PAM has been demonstrated to be effective in the treatment of women with primary breast cancer, particularly those who are premenopausal. Results were achieved with minimal undesirable side effects.

Bone Marrow↗

PubMed1998

Molecular co-operation between protein PAM and streptokinase for plasmin acquisition by Streptococcus pyogenes.

Bacterial surface-associated plasmin formation is believed to contribute to invasion, although the underlying molecular mechanisms are poorly understood. To define the components necessary for plasmin generation on group A streptococci we used strain AP53 which exposes an M-like protein ("PAM") that contains a plasminogen-binding sequence with two 13-amino acid residues long tandem repeats (a1 and a2). Utilizing an Escherichia coli-streptococcal shuttle vector, we replaced a 29-residue long sequence segment of Arp4, an M-like protein that does not bind plasminogen, with a single (a1) or the combined a1a2 repeats of PAM. When expressed in E. coli, the purified chimeric Arp/PAM proteins both bound plasminogen, as well as plasmin, and when used to transform group A streptococcal strains lacking the plasminogen-binding ability, transformants with the Arp/PAM constructs efficiently bound plasminogen. Moreover, when grown in the presence of plasminogen, both Arp/PAM- and PAM-expressing streptococci acquired surface-bound plasmin. In contrast, plasminogen activation failed to occur on PAM- and Arp/PAM-expressing streptococci carrying an inactivated streptokinase gene: this block was overcome by exogenous streptokinase. Together, these results provide evidence for an unusual co-operation between a surface-bound protein, PAM, and a secreted protein, streptokinase, resulting in bacterial acquisition of a host protease that is likely to spur parasite invasion of host tissues.

Antigens, Bacterial↗

PubMed1998

Kringle 2 mediates high affinity binding of plasminogen to an internal sequence in streptococcal surface protein PAM.

Many cells express receptors for plasminogen (Pg), although the responsible molecules in most cases are poorly defined. In contrast, the group A streptococcal surface protein PAM contains a domain with two 13-amino acid residue long repeated sequences (a1 and a2) responsible for Pg binding. Here we identify the region in Pg that interacts with PAM. A radiolabeled proteolytic plasminogen fragment containing the first three kringles (K1-K3) interacted with streptococci expressing PAM or a chimeric surface protein harboring the a1a2 sequence. In contrast, plasminogen fragments containing kringle 4 or kringle 5 and the activable serine proteinase domain failed to bind to PAM-expressing group A streptococci. A synthetic and a recombinant polypeptide containing the a1a2 sequence both bound to immobilized recombinant K2 (rK2) but not to rK1 or rK3. The interaction between the a repeat region and rK2 was reversible, and rK2 completely blocked the binding of Pg to the a1a2 region. The binding of the a repeat containing polypeptide to K2 occurred with an equilibrium association constant of 4.5 x 10(7) M-1, as determined by surface plasmon resonance, a value close to that (1.6 x 10(7) M-1) calculated for the a1a2-Pg interaction. Inhibition experiments suggested involvement of the lysine-binding site of K2 in the interaction. These data demonstrate that K2 contains the major Pg-binding site for PAM, providing the first well defined example of an interaction between an internal Pg-binding region in a protein and a single kringle domain.

Amino Acid Sequence↗

PubMed1984

Introduction of pAM beta 1 into Listeria monocytogenes by conjugation and homology between native L. monocytogenes plasmids.

The broad host range antibiotic resistance plasmid pAM beta 1 was transferred from Streptococcus faecalis to 9 of 15 Listeria monocytogenes strains by conjugation. L. monocytogenes transconjugates could transfer the plasmid either among L. monocytogenes strains or back to S. faecalis. Transfer between the various strains occurred without any detectable plasmid DNA rearrangements. The pAM beta 1 replicon was stable in L. monocytogenes--it was retained without antibiotic selection when the bacteria were grown in culture media or passed in mice--and the presence of pAM beta 1 had no major effect on L. monocytogenes virulence. These data suggest that pAM beta 1 or its derivatives might serve as useful L. monocytogenes cloning vehicles. The data presented also demonstrate that pAM beta 1 is compatible with two different native L. monocytogenes plasmids and that Listeria species harbor native plasmids in addition to the 38.5-megadalton plasmid pRYC16 previously reported by Pérez-Díaz et al. (J. C. Pérez-Díaz, M. F. Vicente, and F. Banquero, Plasmid 8:112-118, 1982). Of 29 L. monocytogenes strains screened, 7 contained plasmid DNA. Four strains had similar if not identical plasmids that were 34 megadaltons in size, whereas three other strains contained either a 53-, 44-, or 32-megadalton plasmid; none of these plasmids has the same restriction patterns as pRYC16. DNA homology experiments indicate that the various plasmids are related and suggest that there may be a common set of sequences present in all of the plasmids examined.

Animals↗

PubMed1991

Heterogeneity in superoxide production as measured by nitro blue tetrazolium reduction from individual PAM.

Heterogeneity in superoxide (O2-.) production (as determined by the reduction of nitro blue tetrazolium to a diformazan precipitate), cell volume, and cell spreading were measured from single rat pulmonary alveolar macrophages (PAM). Of the 330 cells that produced O2-. due to stimulation by adherence, the maximum diformazan produced (MAX) varied between 1.8 and 47.2 fmol and the maximum (initial) rate of diformazan production (R) varied between 2.2 and 81.7 X 10(-3) fmol/s. Only six PAM of 336 analyzed failed to produce O2-. suggesting that O2-. production is not a specific function of a small subpopulation of PAM but rather that all PAM are capable of producing O2-.. Importantly, O2-. production by single cells showed extensive heterogeneity that did not correlate (r2 less than 0.12) with individual cell volumes, suggesting that the observed heterogeneity may not be due to differences in maturation and/or differentiation. However, when the single cell data were grouped into cell volume subfractions small but increasing linear trends (r2 greater than 0.81) in MAX and R were found. This discrepancy suggests that PAM heterogeneity in O2-. fraction cannot be estimated adequately by measurements on subpopulations of cells.

Animals↗

PubMed1999

Immunocytochemical mapping of the amidating enzyme PAM in the developing and adult mouse lung.

The enzyme PAM is required for activation of many peptide hormones. In adult mouse lung, immunostaining for PAM was located in Clara cells, which constitute most of the epithelial cells of the mouse bronchial/bronchiolar tree. Immunoreactivity appeared for the first time in the epithelium on gestational Day 16, being slight and mostly restricted to the apical cytoplasm. As the lung developed, the labeling became gradually stronger and extended throughout the cell. Smooth muscle of airways and blood vessels, and some parenchymal cells, probably macrophages, also showed PAM immunoreactivity. Of the two enzymatically active domains of PAM, only PHM and not PAL immunoreactivity was found at all stages studied. The early appearance of PAM in developing mouse lung, as well as its presence in a variety of tissues, probably indicates a complex role of this enzyme in pulmonary development and function.

Animals↗

PubMed1986

Ten-year results from the National Surgical Adjuvant Breast and Bowel Project (NSABP) clinical trial evaluating the use of L-phenylalanine mustard (L-PAM) in the management of primary breast cancer.

Between 1972 and 1974, patients were entered into a National Surgical Adjuvant Breast and Bowel Project (NSABP) trial to evaluate L-phenylalanine mustard (L-PAM) as an adjuvant to mastectomy in patients with primary breast cancer and pathologically positive axillary nodes. Overall, findings through 10 years of observation indicate an 8% difference in disease-free survival (DFS) (P = .06) and a 5% difference in survival (P = .4). Women less than or equal to 49 years of age who received L-PAM demonstrate a significant (P = .03) prolongation of DFS and a significant (P = .05) survival benefit compared with those who received a placebo. There is a 37% reduction in their mortality and a cumulative odds of survival of 1.67. In that age group, both those with one to three and greater than or equal to 4 positive nodes benefited, but the advantage was greater when there were fewer positive nodes. There was a significant (P = .009) reduction in mortality (64%) and a cumulative odds of survival of 3.25 in patients less than or equal to 49 years old with one to three positive nodes. No advantage from L-PAM was observed in patients greater than or equal to 50 years old. When L-PAM response is related to nuclear grade, a marker of tumor differentiation, there is a highly significant improvement in DFS (less than .001), distant DFS (.001), and survival (.004) through 10 years of observation for all patients with tumors classified as nuclear grade poor (poorly differentiated), regardless of age and nodal status. Mortality was reduced by 32% and the cumulative odds of survival was 2.10 at 10 years. Of singular importance is the observation of a benefit in those greater than or equal to 50 years of age as well as in those less than or equal to 49 years of age with poorly differentiated tumors. There is a significant (P = .003) survival benefit for those in the older age group with a 37% reduction in mortality, and a cumulative odds of survival of 2.75. Patients in both age groups with well-differentiated tumors demonstrated no benefit from L-PAM. Those who are older seem to do less well following chemotherapy. We conclude that tumor differentiation is a better discriminant of response to chemotherapy than is age, and that both younger and older women are responsive to adjuvant chemotherapy when they have poorly differentiated tumors.

Actuarial Analysis↗

PubMed1984

Aryl hydrocarbon hydroxylase induction in rat pulmonary alveolar macrophages (PAMs) by diesel particulates and their extracts.

The Aryl hydrocarbon hydroxylase (AHH) activity in the lavaged PAMs was investigated in male Fischer rats after inhalation of diluted diesel exhaust (DE), and compared with intratracheal instillation of the organic solvent extract of hydrocarbons adsorbed on the particulate surface. Animals were exposed to concentrations of 1500 micrograms/m3 or 6000 micrograms/m3 of diesel particulates, 20 hrs/day, 7 days/wk for 2 days up to 28 days, or treated with a single intratracheal dose of DE extract or benzo[a]pyrene (B[a]P) dissolved in gelatin-saline solution. The counts of lavageable PAM and polymorphonuclear leukocytes (PMN) were significantly elevated in the exposed rats. However, a decrease of AHH activity was found in the PAM cells after four weeks of exposure to both particulate concentrations. The AHH activity in the PAMs from rats injected intratracheally with 5 mg/kg of B[a]P was slightly increased; no change was observed in PAMs similarly treated with DE extract. Enzyme induction is not noted because of absence of sufficient quantities of hydrocarbons need for induction. This could be further potentiated that macrophages metabolize and perhaps reduce hydrocarbon levels by translocation.

Animals↗

PubMed1985

Correlation of 2-PAM plasma levels after organophosphate intoxication.

In order to investigate the pathophysiological effects of organophosphorus poisoning on therapeutic compounds, multiples of the LD50 for sarin and soman were injected into guinea pigs after which 2-PAM and atropine sulfate were administered intramuscularly. It was found that intoxication by sarin or soman in therapeutically treated animals resulted in modifications of plasma oxime concentrations. Peak plasma (CPmax) concentrations and areas under the curve (AUC) between 1 to 10 min after the injection of 2-PAM were altered in a systematic fashion which correlated to the multiple of the LD50 (r greater than 0.9498). The effect of the sarin and soman was studied at fractions of the LD50, i.e. 0.7s, 1.5, 2.2, 2.8, 5.6, 11.2. The influence of the organophosphorus poisons on the plasma concentration of 2-PAM is biphasic. Multiples of the LD50 equal to or below 2.2 tend to decrease, whereas multiples equal to or above 2.8 tend to increase CPmax and AUC in different groups of animals. Changes in the plasma concentrations of 2-PAM may result from alterations in blood flow rates and patterns which would alter the distribution and elimination of 2-PAM.

Animals↗

PubMed1978

Central therapeutic effects of dihydroderivative of pralidoxime (pro-2-PAM) in organophosphate intoxication.

Central actions of pro-2-PAM (dihydroderivative of 2-PAM) and 2-PAM in poisonings with DFP have been studied. It was shown that pro-2-PAM significantly increased activity of DFP inhibited acetylcholinesterase in the brain, quickly ceased the DFP-induced paralysis of respiration, partially normalized the DFP-induced abnormalities in electrocorticogram and increased the convulsive dosis of DFP. Effects of 2-PAM in these experiments were negligible.

Animals↗

PubMed1996

The combination of cisplatin, doxorubicin, and mitomycin (PAM) compared with the FAM regimen in treating advanced gastric carcinoma. A phase II randomized trial of the Italian Oncology Group for Clinical Research.

BACKGROUND: In a randomized Phase II study, the authors evaluated the activity and toxicity of the new cisplatin, doxorubicin, and mitomycin C (PAM) combination, that includes cisplatin (P) instead of 5-fluorouracil as in the 5-fluorouracil, doxorubicin, and mitomycin C (FAM) combination, in patients with advanced gastric carcinoma. FAM was utilized as a control treatment arm. METHODS: Fifty eligible patients were assigned to the FAM (5-fluorouracil 600 mg/m2 intravenous (i.v.) on Days 1, 8, 29, 36; doxorubicin 30 mg/m2 i.v. on Days 1 and 29; mitomycin C 10 mg/m2 i.v. on Day 1; every 8 weeks) and 52 to the PAM combination (cisplatin 60 mg/m2 i.v. on Days 1 and 29; doxorubicin 30 mg/m2 i.v. on Days 1 and 29; mitomycin C 10 mg/m2 i.v. on Day 1; every 8 weeks). All eligible patients were included in the evaluation of response, toxicity and survival. RESULTS: The PAM combination complete response (CR) rate was 8%, and the CR plus partial response (PR) rate was 21% (95% confidence interval [CI] from 10% to 32%). The median time to progression, duration of response, and duration of survival were 15, 26, and 29 weeks, respectively. The FAM combination CR rate was 2% and the CR plus PR rate was 26% (95% CI from 14% to 38%). The median time to progression, duration of response, and duration of survival were 17, 27, and 23 weeks, respectively. Hematologic and nonhematologic toxicity were mild with both regimens. CONCLUSIONS: This study shows that this new combination, that does not include 5-fluorouracil, is active in patients with advanced gastric carcinoma. Since treatment with 5-fluorouracil alone is still considered the standard according to some authors, the PAM combination may be included among the sequential clinical options before or after treatment with 5-fluorouracil alone.

Adult↗