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PubMed1979

Origin, Kinetics, and characteristics of pulmonary macrophages in the normal steady state.

Pulmonary macrophages of mice in the steady state were isolated by lavage with PBS containing EDTA and subsequent enzymatic digestion of tissue with pronase and DNA-ase. By this method, the total pulmonary macrophage population was obtained in two cell suspensions, one with a pure population of pulmonary alveolar macrophages (PAM) and the other with a mixed population of pulmonary alveolar and pulmonary tissue macrophages (PTM). The morphological, cytochemical, and functional characteristics of both PAM and PTM were like those of mature tissue macrophages except for the presence of C3 receptors. These receptors were almost absent on PAM and present on a larger number of cells in the mixed population of PAM and PTM. The total pulmonary macrophage population of mice in the steady state is approximately equal to 2 x 10(6), of which about 93% are PAM and about 7% are PTM. In labeling experiments with 3H-thymidine, the low in vitro labeling indices (less than 3%) for both PAM and the mixture of PAM and PTM, showed that both are essentially nondividing cells. In vivo labeling studies showed an increase in the number of labeled macrophages that can only be attributed to labeled monocytes migrating into the lungs. Additional evidence was provided by a decrease in the labeling indices of pulmonary macrophages when mice were treated with hydrocortisone acetate, which causes a severe monocytopenia, thus preventing monocyte influx into the lungs. Confirmation of the bone marrow origin was obtained in mice labeled after x-irradiation with partial bone marrow shielding: labeled pulmonary macrophages were found in the exposed lungs. In all experiments, the labeling indices were identical in the two macrophage populations isolated. These results show that the influx of monocytes is the source of cell renewal for the pulmonary macrophages. No indications for an interstitial division or maturation compartment in the lung were found. Quantitation of the efflux of labeled monocytes from the blood, and the number of labeled pulmonary macrophages, showed that in the steady state about 15% of the monocytes leaving the circulation become pulmonary macrophages and that the turnover time of pulmonary macrophages is approximately equal to 27 d.

Animals↗

PubMed2026

Structure-Function Analysis of the Benzyloxy Moiety of the Delta-Opioid Receptor Positive Modulator BMS-986187: Identification of a Derivative with High Selectivity for the Delta-Opioid Receptor over the Mu-Opioid Receptor In Vitro and In Vivo.

Positive allosteric modulators (PAMs) of the delta-opioid receptor (DOR) enhance endogenous opioid signaling while avoiding the convulsant liability of orthosteric agonists. However, the prototypical DOR-PAM, BMS-986187, also potentiates mu-opioid receptor (MOR) signaling, raising concerns regarding respiratory depression and abuse liability. Here, we report a structure-activity study of the benzyloxy moiety of BMS-986187 to improve selectivity for DOR over MOR, while retaining DOR-PAM potency. Fifty-two new analogues and 12 previously reported ones featuring mono- and disubstitution of the benzyl ring and phenyl-heterocycle replacements were synthesized and evaluated in β-arrestin2 recruitment assays. Ortho-substituted derivatives consistently enhanced DOR-PAM potency, although often increased MOR-PAM activity. One pyridyl derivative (compound 35) retained high DOR-PAM potency and efficacy (EC50 = 0.1 μM, Emax = 91%) with no detectable MOR activity. In mice, compound 35 enhanced DOR-mediated reversal of nitroglycerin-induced hyperalgesia, an effect absent in DOR-knockout mice, without enhancing MOR-mediated antinociception, demonstrating in vivo selectivity.

Receptors, Opioid, delta↗

PubMed1979

Drug uptake into everted intestinal sacs. I. Enhancement by hypertonicity.

The transfer of the cationic drugs, pralidoxime (PAM) and tetraethylammonium, and anionic ampicillin from the mucosal-to-serosal sides of everted rat jejunal sacs is enhanced by mucosal hypertonicity. PAM uptake, which is proportional to initial mucosal concentrations up to 2.3 mM, is enhanced by mucosal hypertonicity due to addition of sodium, potassium, lithium and choline chloride, sodium sulfate, and the nonionic solutes, urea, sucrose, and mannitol. Bicarbonate, Tris, or phosphate buffer and the presence of magnesium and calcium do not affect this hypertonicity-induced acceleration of PAM passage. Serosal osmolality has no effect on transfer and mucosal hypertonicity is equally effective in the presence and absence of a transmural osmotic gradient. This observation and minimal changes in the concentration of inulin placed in the sacs suggest that fluid shifts and solvent drag are not responsible for the enhanced mucosal-to-serosal transfer of PAM from hypertonic buffer. Mucosal hypertonicity at 450 mosmol/kg causes reversible enhancement of PAM transfer, whereas the effect of 600 mosmol/kg cannot be reversed by replacing the tissue in isotonic buffer. The effect of osmotic manipulation on PAM transfer across the intestine thus differs from its effect on the passage of other ionized species and drugs across other epithelia.

Ampicillin↗

PubMed1979

Induction of ouabain-resistant mutation and sister chromatid exchanges in Chinese hamster cells with chemical carcinogens mediated by human pulmonary macrophages.

Pulmonary macrophages (PAM) metabolically activated benzo[a]pyrene [B(a)P] and its proximate carcinogenic metabolite, (+/-)trans 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (7,8-diol), to ultimate mutagens that were detected in cocultivated Chinese hamster V79 cells. Increases in the frequency of ouabainresistant (O(r)) mutations and sister chromatid exchanges were found in V79 cells only when they were cocultivated with both PAM and the chemical procarcinogens. 7,8-Diol caused higher frequencies of both O(r) mutations and sister chromatid exchanges than did the parent compound, B(a)P. When metabolically activated by PAM the mean O(r) mutation frequency caused by B(a)P was 9 O(r) mutants/10(6) surviving V79 cells per 10(6) PAM and a 10-fold interindividual variation (range, 2-21) was found. The mean O(r) mutation frequency caused by 7,8-diol was 64 and a ninefold interindividual variation (range, 14-120) was found. In the absence of PAM, the O(r) mutation frequency in V79 cells was one or less O(r) mutant per 10(6) survivors. 7,8-Benzoflavone, an inhibitor of mixed function oxidases, reduced the frequencies of O(r) mutations and of sister chromatid exchanges in V79 cells caused by 7,8-diol and B(a)P. As expected 7,8-benzoflavone did not influence the frequency of O(r) mutations caused by one of the ultimate mutagens derived from B(a)P and 7,8-diol, (+/-)7beta, 8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene. These data are consistant with the hypothesis that PAM may play a role in the activation of environmental chemical procarcinogens.

Adenocarcinoma↗

PubMed1979

Hypersensitivity reactions to iv melphalan during treatment of multiple myeloma: Cancer and Leukemia Group B experience.

Ten patients developed allergic reactions to iv melphalan (L-PAM) during therapy for multiple myeloma. The incidence of such reactions was 2.4% among 425 patients receiving iv L-PAM with or without other drugs and 3.9% among 255 patients receiving iv L-PAM alone. Only one such reaction was demonstrated in 294 patients who initially received oral L-PAM. The median day of first reaction to iv L-PAM was Day 222 (range, Days 44-909) and the median total dose prior to a reaction was 185 mg (range, 51-250 mg). Of five patients who subsequently received oral L-PAM, four developed a reaction similar to that experienced with the iv drug.

Administration, Oral↗

PubMed1979

Application of a simple high-performance liquid chromatographic method for the determination of melphalan in the presence of its hydrolysis products.

A procedure for the separation and quantitation of melphalan (L-PAM) and its hydrolysis products by high-performance liquid chromatography is described. The hydrolysis of L-PAM at 25 +/- 0.1 degrees and 41 +/- 0.1 degrees was studied between pH 3.0 and 9.0. The pattern of hydrolysis suggested that L-PAM decomposes via two consecutive pseudo first-order reactions. Pseudo first-order rate constants (k1) were determined for the disappearance of L-PAM at various pH values in buffered solutions and in a formulated product. At both temperatures L-PAM solutions were found to be most stable at low pH. Chloride ion was found to reduce the rate of hydrolysis.

Chromatography, High Pressure Liquid↗

PubMed1979

Phagocytosis of asbestos fibers by human pulmonary alveolar macrophages.

Human pulmonary alveolar macrophages (PAMs) were cultured for 24--72 h with varying concentrations (0--300 microgram/ml) of amosite asbestos (AS). At lower AS concentrations, (less than 100 microgram/ml) no decrease in cell viability occurred during the first 24 h of culture. Significant cytotoxicity (P less than 0.005 in all instances) was observed, however, following incubation for 24 h with higher AS concentrations (greater than 100 microgram/ml). Even following incubation with lower concentrations of AS, significant cytotoxicity (P less than 0.006 in all instances) was observed after 48 or 72 h of culture. Scanning electron microscopy (SEM) clearly illustrates the various stages of AS phagocytosis by PAMs. SEM also documented morphological changes in PAMs following AS exposure. These included increased zeiosis and the appearance of a fibrous-like material on the surface of AS fibers following initial contact with the PAM cytoplasmic membrane. Further study of the biological interactions between AS and human cells, such as PAMs, might provide valuable information regarding the etiology of AS-related lung disorders.

Adult↗

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↗

PubMedDate not supplied

A method for the measurement of L-phenylalanine mustard in the mouse and dog by high-pressure liquid chromatography.

The distribution of L-phenylalanine mustard (L-PAM) was studied in dogs and mice by high-pressure liquid chromatography. Separation of L-PAM from its products of hydrolysis was accomplished with a mu-Bondapak C18 column, a solvent system composed of 2-methoxyethanol/0.1% acetic acid, and solvent programming with a step gradient. Complete separation was effected in less than 15 min. The half-life for disappearance of L-PAM from mouse blood was 41 min, whereas that from dog blood was 29 min. The monohydroxy derivative of L-PAM, L-MOH, disappeared from dog serum with a half-life of 32 min. L-MOH was not detectable in mouse tissue other than blood at times greater than 15 min after injection. In the dog at 4 hr after injection, the tissue/serum concentration ratios were greater than 1 for liver, spleen, intestine, skeletal muscle, urinary bladder and gallbladder. The concentration of L-PAM in the bile was approximately 500 times higher than that in serum.

Animals↗

PubMed1976

Preclinical warning of recrudescent mammary cancers by pregnancy-associated alpha-macroglobulin.

Nine of 30 mammary cancer patients developed metastases during 13-94 months after mastectomy. All 9 patients had elevated blood levels of pregnancy-associated alpha-macroglobulin (PAM) 1-21 months before conventional detection of metastases. Seven of the clinically well patients had PAM rises exceeding 90 per cent above the baseline and in 4 of these the PAM later fell to lower levels. PAM appears to have potential as an indicator of the growth of micrometastases.

Adult↗

PubMed1979

Isolation and characterization of fibroblasts obtained by pulmonary lavage of human subjects.

Cells that possess the morphology and collagen synthetic capacity of fibroblasts were recovered by bronchofiberscopic subsegmental pulmonary lavage from patients with pulmonary fibrosis, from patients with miscellaneous nonfibrotic lung diseases and from healthy volunteers. Lavage cells were placed in tissue culture, observed for 2 to 6 weeks, and compared with human lavage pulmonary alveolar macrophages (PAM), WI-38 and IMR-90 human fetal lung fibroblasts, and adult lung tissue fibroblasts (CLAC-76). Lavage fibroblsts (LF) were identified as proliferating clones in monolayers of nonproliferating PAM and could be subcultured repeatedly. Fibroglasts were propagated from 28 of the 92 lavage specimens cultured. Time-lapse cinematography showed similar distributions of interdivision times for LF, CLAC-76 and WI-38, but the LF and CLAC-76 lines had slower mean migration rates than the fetal line. Light, scanning, and transmission electron microscopy of LF showed attenuated spindle-shaped cells with interdigitating filopodia, flat surfaces with few microvilli, and containing numerous cytoplasmic polyribosomes and rough endoplasmic reticulum. Extracellular fibrils with the appearance of collagen were seen. Collagen synthesis by LF was measured as 3.9% to 4.9% of the cell-associated protein sensitive to bacterial collagenase. This protein was rich in hydroxyproline, and had an electrophoretic migration pattern identical to known collagen. LF did not contain lysozyme although this enzyme was abundant in fresh and 1-week cultured PAM. Thus LF were similar to human fetal and adult lung tissue fibroblasts in their morphology, tissue culture characteristics, constitutive enzymes and collagen synthetic properties but were distinctly different from PAM.

Cell Line↗

PubMed2025

RNA-DNA hybrid binding domain broadens the editing window of base editors.

Adenine base editors (ABEs) and cytosine base editors (CBEs) are prominent tools for precise genome editing but are hindered by limited editing activity at positions proximal to the protospacer adjacent motif (PAM). This study investigates the potential of enhancing base editors editing activity by fusing them with RNA-DNA hybrid binding domains (RHBDs). Specifically, fusing ABE8e with the RHBD of Homo sapiens RNaseH1 (RHBD1) significantly increased A-to-G editing efficiency in the PAM-proximal region (A9-A15) by up to 3.5-fold, while reducing off-target cytosine editing. Additionally, RHBD1 is compatible with ABEmax, BE4max, and dual base editor (eA&C-BEmax), enhancing their editing activity at the PAM-proximal bases. Notably, RHBD1-fused BE4max led to a 3.1-fold improvement in C-to-T editing efficiency at PAM-proximal region (C9-C12). Furthermore, we demonstrated that RHBD1-fused ABE8e could effectively edit disease-related single nucleotide variations (SNVs) in human cells and validated its efficacy in adult mouse liver. These findings highlight the significance of the RHBD in expanding editing window and the applicability of base editors for gene therapy and disease modeling.

Gene Editing↗

PubMed2026

A compound heterozygous combination of SLC34A2 variants in pulmonary alveolar microlithiasis: A case report and literature review.

Pulmonary Alveolar Microlithiasis (PAM) is a rare hereditary lung disorder characterized by the intra-alveolar deposition of calcium phosphate microliths. It is primarily familial and follows an autosomal recessive inheritance pattern, with no significant gender disparity in incidence. In its early stages, PAM is often asymptomatic, and most cases are detected incidentally through abnormal imaging findings during routine health examinations. We report a case of a male patient in his mid-50 s with a 10-year history of exertional dyspnea and cough unresponsive to conventional therapy. Initially diagnosed and treated for emphysema in early 2024, the patient was readmitted two months later with progressive dyspnea and cyanosis. The diagnosis of PAM was confirmed by typical medical imaging and pathological examination. Genetic analysis identified a previously unreported compound heterozygous combination of SLC34A2 variants: a c.910A > T (p.Lys304*) nonsense variant in exon 8 and a heterozygous ∼5.5 kb copy-number deletion at 4p15.2 (encompassing exons 2-6), thereby expanding the catalogue of reported PAM-associated genetic combinations. No recurrence was observed during one-year follow-up after bilateral lung transplantation.

Humans↗

PubMed1975

Nucleotide sequence of U-2 ribonucleic acid. The sequence of the 5'-terminal oligonucleotide.

The nucleotide sequences were determined for the 5'-oligonucleotides obtained by complete pancreatic RNase digestion (P25) and complete T1 RNase digestion (T27) of U-2 RNA. Complete digestion of oligonucleotide P25 with snake venom phosphodiesterase produced pm3 2,2,7G, pAm, pUm, and pCp in approximately equimolar ratios. Partial digestion of these oligonucleotides with snake venom phosphodiesterase produced -Um-C-Gp and pAm-Um, indicating the sequence of the 3'-terminal portion of the 5'-oligonucleotide is pAm-Um-C-Gp. The 5'-terminal oligonucleotide did not contain a 5'-phosphate and no free nucleoside was released from the 5' end by venom phosphodiesterase digestion. Since free pm3 2,2,7G was released by digestion with nucleotide pyrophosphatase and limited digestion with snake venom phosphodiesterase, this nucleotide is apparently linked to pAm in a pyrophosphate linkage. Mass spectrometry and thin layer chromatography in borate systems showed the ribose of m3 2, 2, 7G contains no 2'O-methyl residue. Moreover, the finding that the ribose of m3 2, 2, 7G was oxidized by NaIO4 and reduced by KB3H4 in intact U-2 RNA rules out other linkages involving the 2' and 3' positions. Accordingly, it is concluded that the structure of the 5'-terminal pentanucleotide of U-2 RNA is(see article).

Alkaline Phosphatase↗

PubMed1978

[Toxicity of oximes and their effect on acetylcholinesterase activity in the blood and myoneural synapses of animals].

The effect was followed up of 2-PAM and Toxogonin (T), reactivators of choline esterase, at a single muscular application on the activity of acetylcholine esterase (ES 3.1.1.7) (ACE) of whole blood (WB) and the myoneural synapses (MS) of an interrib muscle. It was found that a species-specific effect was produced by T and 2-PAM on ACE of WB and MS in lambs and sheep. Optimal doses of 50 and 80 mg/kg led to a slight drop in the activity of ACE at the 2nd hour following injection, after which it rose gradually up to values that were higher than the initial ones for more than ten days. 100 and 200 mg/kg led to a more sensitive and long-term drop in the activity of ACE (up to 48h--72nd hour), after which it likewise rose above the initial value, and came back to normal on the 13th day. With lambs the reaction was analogous, though weaker. In rats and rabbits there was no change in the activity of ACE of WB and MS following the use of oximes. The optimal nontoxic and inductoenzyme rates of the two oximes for lambs and sheep proved to be about 50 mg/kg. It was established that both for rats and for sheep and lambs T was almost twice as toxic as 2-PAM. Intoxication with T was characterized by severe hemorrhagic and necrotic nephroso-nephritis, acute toxic dystrophy of the liver, and ulcerous, necrotic enteritis. 2-PAM was found to potentiate the toxic effect of T.

Acetylcholinesterase↗

PubMed1979

Effects of 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide, 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea, and L-phenylalanine mustard on B16, Cloudman S91, and Harding-Passey mouse melanomas.

The effects of 5-(3,3-Dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC), 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea (MeCCNU), and L-phenylalanine mustard (L-PAM) have been compared by using three i.p. transplanted mouse melanomas: the B16 melanoma in C57BL/6 mice; the Harding-Passey (HP) malanoma in BALB/c X DBA/2F1 (hereafter called CD2F1) mice; and the Cloudman S91 melanoma in DBA/2 mice. HP melanoma responds well to all three drugs. S91 responds only to L-PAM and MeCCNU. DTIC may accelerate death in mice bearing this tumor. B16 responds well to L-PAM and moderately well to MeCCNU and to multiple injections of DTIC. The best response to DTIC and MeCCNU is given by HP, while the best response to L-PAM is given by S91. Tumor cell-doubling times were found to be 1.5 days for B16, 2 DAYS FOR HP, and 3 days for S91. HP would seem to be the most responsive malanmoma with respect to the 3 agents studied. This may be due to an interaction between the chemotherapeutic agents and the host immune response, since the HP tumor arose in a noninbred mouse and is thus nonsyngeneic with the CD2F1 host. All three tumors appear to be interesting biological models for studying drug combinations and combined therapeutic modalities against melanoma.

Animals↗

PubMed1977

Identification of pregnancy-associated alpha-macroglobulin on the surface of peripheral blood leucocyte populations.

Pregnancy-associated alpha-macroglobulin (PAM) was identified on the surface membranes of human peripheral blood leucocytes by immunofluorescent staining. Subjects having a high serum-level of the glycoprotein (pregnant and contraceptive steroid-treated women) were shown to possess a significantly greater proportion of PAM-positive cells than those (normal males) with a low concentration. However, no correlation was found between the serum values and the percentage of PAM-associated leucocytes. Studies employing purified leucocyte-types and the simultaneous detection of PAM and lymphocyte surface markers indicated that only subpopulations of T lymphocytes (23%) and monocytes (40%) were associated with this serum protein.

Adult↗

PubMed1979

Combination chemotherapy for soft-tissue sarcomas: a phase III study.

A total of 144 patients with advanced sarcomas were entered into a randomized prospective protocol with four treatment arms utilizing different combinations of chemotherapeutic agents. Of these, 120 patients (83%) were judged acceptable. Treatment 1: actinomycin-D (Act-D), 0.01 mg/kg IV, days 1--5; phenylalanine mustard (L-PAM), 4 mg PO, days 1--10 every six weeks. Treatment 2: Act-D, 0.01 mg/kg IV, days 1--5; L-PAM, 4 mg PO, days 1--10; vincristine, 1 mg IV, days 1, 8, 15, 22, 29, 36, repeat every six weeks. Treatment 3: Act-D, 0.01 mg/kg IV, days 1--5; L-PAM, 4 mg PO, DAYS 1--10; NSC-1026, 200 mg/kg IV, days 1--6. Treatment 4: Adriamycin, 0.4 mg/kg IV, days 1, 2, 3, 8, 9, 10, then 2XWK starting day 15 (max. 1,200 mg). There was a provision that upon progression of the disease in the first three treatment regimens, patients would be crossed over to Treatment 4. Responses were as follows: 1 - Partial Response (PR) 1/25; No Change (NC) 9/25 (36%). gF2 - NC 17/26 (65%). 3 - NC 13/25 (52%). 4 - Complete Response (CR) 1/41; PR 6/41; (15%); NC 27/41 (66%). Clearly Treatment 4 was the best arm, with a 17% response rate and an initial progression rate of 17%. The only other response was a partial in 1. The difference is statistically significant (H = 17.247, P = 0.0006). If the responders to Adriamycin were analyzed without crossovers, the response rate would be 22% (6/27). (H = 14.079, P = 0.003). Median times to progression were 12.5, 8.7 weeks for 1 and 2, and 5 weeks for 3 and 4. There was no significant difference in the median survival times among the four treatment arms. It appears that Adriamycin as a single drug is superior to the drug combinations and would probably be even more effective used in combination with known active agents.

Antineoplastic Agents↗