[Automatic classification of immune-mediated glomerular diseases based on multi-modal multi-instance learning].

OBJECTIVE: To develop a multi-modal deep learning method for automatic classification of immune-mediated glomerular diseases based on images of optical microscopy (OM), immunofluorescence microscopy (IM), and transmission electron microscopy (TEM). METHODS: We retrospectively collected the pathological images from 273 patients and constructed a multi-modal multi- instance model for classification of 3 immune-mediated glomerular diseases, namely immunoglobulin A nephropathy (IgAN), membranous nephropathy (MN), and lupus nephritis (LN). This model adopts an instance-level multi-instance learning (I-MIL) method to select the TEM images for multi-modal feature fusion with the OM images and IM images of the same patient. By comparing this model with unimodal and bimodal models, we explored different combinations of the 3 modalities and the optimal methods for modal feature fusion. RESULTS: The multi-modal multi-instance model combining OM, IM, and TEM images had a disease classification accuracy of (88.34±2.12)%, superior to that of the optimal unimodal model [(87.08±4.25)%] and that of the optimal bimodal model [(87.92±3.06)%]. CONCLUSION: This multi- modal multi- instance model based on OM, IM, and TEM images can achieve automatic classification of immune-mediated glomerular diseases with a good classification accuracy.

A comparison study of pathological features and drug efficacy between Drosophila models of C9orf72 ALS/FTD.

Amyotrophic lateral sclerosis is a devastating neurodegenerative disease with a complex genetic basis, presenting both in familial and sporadic forms. The hexanucleotide (G4C2) repeat expansion in the C9orf72 gene, which triggers distinct pathogenic mechanisms, has been identified as a major contributor to familial and sporadic Amyotrophic lateral sclerosis cases. Animal models have proven pivotal in understanding these mechanisms; however, discrepancies between models due to variable transgene sequence, expression levels, and toxicity profiles complicate the translation of findings. Herein, we provide a systematic comparison of 7 publicly available Drosophila transgenes modeling the G4C2 expansion under uniform conditions, evaluating variations in their toxicity profiles. Further, we tested 3 previously characterized disease-modifying drugs in selected lines to uncover discrepancies among the tested strains. Our study not only deepens our understanding of the C9orf72 G4C2 mutations but also presents a framework for comparing constructs with minute structural differences. This work may be used to inform experimental designs to better model disease mechanisms and help guide the development of targeted interventions for neurodegenerative diseases, thus bridging the gap between model-based research and therapeutic application.

Adjuvant Chemotherapy With UFT/LV Versus UFT/LV Plus PSK in Stage II/III Colorectal Cancer.

BACKGROUND/AIM: Uracil-tegafur+leucovorin (UFT/LV), an oral adjuvant therapy for stage II/III colorectal cancer, is non-inferior to standard weekly fluorouracil and folinate. Although polysaccharide K (PSK) has been evaluated as a postoperative adjuvant colorectal cancer drug, its efficacy remains unclear. This randomized phase II trial compared UFT/LV+PSK with UFT/LV as adjuvant chemotherapy. PATIENTS AND METHODS: Between April 2011 and August 2016, 186 patients who underwent radical resection randomly received 6 months of UFT/LV (Group A: 300 mg/m2/day UFT and 75 mg/day LV, every 35 days for five cycles), 6 months of UFT/LV+PSK (Group B: standard UFT/LV regimen and daily administration of 3 g/day of PSK), or 12 months of UFT/LV+PSK (Group C). The primary endpoint was the 3-year disease-free survival. RESULTS: Groups A, B, and C consisted of 37, 75, and 74 patients, of which treatment was completed by 33 (89.2%), 63 (84.9%), and 53 (70.4%) patients, respectively (p=0.0279). Adverse event incidence for all grades were 59.5%, 52.1%, and 59.2%, and for grade ≥3 were 13.5%, 9.6%, and 9.9%, respectively. The 3-year disease-free survival rates were 72.5%, 82.2%, and 74.2%, respectively, with no significant differences. The preoperative lymphocyte ratio did not significantly differ between groups. CONCLUSION: UFT/LV+PSK is comparable to UFT/LV therapy in terms of prognostic efficacy and reduced adverse effects. Thus, UFT/LV+PSK is a useful adjuvant chemotherapy option for patients with high-risk stage II/III colorectal cancer.

Long-term oncological outcomes of robotic versus laparoscopic gastrectomy for gastric cancer: multicentre cohort study.

BACKGROUND: The aim of this multicentre cohort study was to compare the long-term oncological outcomes of robotic gastrectomy (RG) and laparoscopic gastrectomy (LG) for patients with gastric cancer. METHODS: Patients with gastric cancer who underwent radical gastrectomy by robotic or laparoscopic approaches from 1 March 2010 to 31 December 2018 at 10 high-volume centres in China were selected from institutional databases. Patients receiving RG were matched 1 : 1 by propensity score with patients undergoing LG. The primary outcome was 3-year disease-free survival. Secondary outcomes were overall survival and disease recurrence. RESULTS: Some 2055 patients who underwent RG and 4309 patients who had LG were included. The propensity score-matched cohort comprised 2026 RGs and 2026 LGs. Median follow-up was 41 (i.q.r. 39-58) months for the RG group and 39 (38-56) months for the LG group. The 3-year disease-free survival rates were 80.8% in the RG group and 79.5% in the LG group (log rank P = 0.240; HR 0.92, 95% c.i. 0.80 to 1.06; P = 0.242). Three-year OS rates were 83.9 and 81.8% respectively (log rank P = 0.068; HR 0.87, 0.75 to 1.01; P = 0.068) and the cumulative incidence of recurrence over 3 years was 19.3% versus 20.8% (HR 0.95, 0.88 to 1.03; P = 0.219), with no difference between groups. CONCLUSION: RG and LG in patients with gastric cancer are associated with comparable disease-free and overall survival.

Minimally invasive liver resection for cholangiolocellular carcinoma: A single-institution experience.

INTRODUCTION: Cholangiolocellular carcinoma (CoCC) resembles cholangiocellular carcinoma (CCC) and presents a variety of imaging findings; thus, preoperative diagnosis is often difficult. METHODS: We retrospectively studied patients who were diagnosed with CoCC at the Kansai Rosai Hospital from 2006 to 2021 and treated by laparoscopic liver resection (LLR) or open liver resection (OLR). RESULT: Among 918 liver resections, 15 patients were diagnosed with CoCC: 11 underwent LLR and 4 OLR. For LLR and OLR, respectively, patient age was 69.9 ± 6.8 and 72.8 ± 10.6, sex was M/F: 10/1 and 2/2, Child-Pugh was A/B/C: 10/1/0 and 4/0/0, liver damage was A/B/C: 8/3/0 and 4/0/0, preoperative diagnosis was CoCC/CCC/HCC: 1/2/8 and 2/2/0, pathological stage of Union for International Cancer Control (UICC) was IA/IB/II/IIIA/IIIB/IV: 8/0/2/1/0/0 and 0/0/3/0/1/0 (p = .0312), and extent of liver resection was Hr0/HrS/Hr1/Hr2/: 3/0/5/3 and 1/1/0/2. In LLR and OLR, respectively, operation time was 417.5 ± 191.0 and 407.5 ± 187.9 min, blood loss was 123.3 ± 217.4 and 1385.0 ± 1038.7 mL, and postoperative hospital stay was 12.2 ± 13.7 and 15.0 ± 6.6 days. For stages I and II/III, respectively, the 5-year disease-free survival rates were 100.0% and 34.3%, and the 5-year overall survival rates were 100.0% and 55.6%. For stage II/III LLR and OLR, respectively, the 3-year disease-free survival rates were 33.3% and 37.5% (p = .8418), and the 5-year overall survival rates were 66.7% and 50.0% (p = .8084). CONCLUSION: Although further studies are still needed to confirm, minimally invasive liver resection without lymph node dissection is one of a safe and effective approach to the management of CoCC.

Survival outcomes of patients with stage III colorectal cancer aged ≥ 80 years who underwent curative resection: the HiSCO-04 prospective cohort study.

BACKGROUND: The efficacy of adjuvant chemotherapy in elderly patients aged ≥ 80 years with stage III colorectal cancer remains unclear. In parallel with a multicenter prospective phase II trial evaluating the efficacy of uracil-tegafur and leucovorin as adjuvant chemotherapy (HiSCO-03), we conducted a prospective observational study of these patients to assess survival outcomes, including those ineligible for chemotherapy. METHODS: This multi-institutional prospective cohort study included 17 institutions in Hiroshima, Japan. Patients aged ≥ 80 years with stage III colorectal cancer who underwent curative resection were enrolled. The primary endpoint was 3-year disease-free survival, and the secondary endpoints were 3-year overall and relapse-free survival. Propensity score matching was used to assess the effects of adjuvant chemotherapy on survival outcomes. RESULTS: A total of 214 patients were analyzed between 2013 and 2018, including 99 males and 115 females with a median age of 84 years (range 80-101 years). Recurrence occurred in 58 patients and secondary cancers were observed in 17. The 3-year disease-free, overall, and relapse-free survival rates were 63.3%, 76.9%, and 62.9%, respectively. Adjuvant chemotherapy was administered to 65 patients with a completion rate of 52%. In a study of 80 patients that adjusted for background factors using propensity score matching, patients who completed the planned treatment showed improved disease-free survival (3-year disease-free survival: completed, 80.0%; not received, 65.5%; and discontinued, 56.3%; p = 0.029). CONCLUSIONS: Completion of adjuvant chemotherapy may improve the prognosis of patients with colorectal cancer aged ≥ 80 years, although the number of patients who would benefit from it is limited.

Systematic identification of intron retention associated variants from massive publicly available transcriptome sequencing data.

Many disease-associated genomic variants disrupt gene function through abnormal splicing. With the advancement of genomic medicine, identifying disease-associated splicing associated variants has become more important than ever. Most bioinformatics approaches to detect splicing associated variants require both genome and transcriptomic data. However, there are not many datasets where both of them are available. In this study, we develop a methodology to detect genomic variants that cause splicing changes (more specifically, intron retention), using transcriptome sequencing data alone. After evaluating its sensitivity and precision, we apply it to 230,988 transcriptome sequencing data from the publicly available repository and identified 27,049 intron retention associated variants (IRAVs). In addition, by exploring positional relationships with variants registered in existing disease databases, we extract 3,000 putative disease-associated IRAVs, which range from cancer drivers to variants linked with autosomal recessive disorders. The in-silico screening framework demonstrates the possibility of near-automatically acquiring medical knowledge, making the most of massively accumulated publicly available sequencing data. Collections of IRAVs identified in this study are available through IRAVDB ( https://iravdb.io/ ).

Synthesis and antiangiogenic activity of N-alkylated levamisole derivatives.

Inhibition of angiogenesis is a promising addition to current cancer treatment strategies. Neutralization of vascular endothelial growth factor by monoclonal antibodies is clinically effective but may cause side effects due to thrombosis. Low molecular weight angiogenesis inhibitors are currently less effective than antibody treatment and are also associated with serious side effects. The discovery of new chemotypes with efficient antiangiogenic activity is therefore of pertinent interest. (S)-levamisole hydrochloride, an anthelminthic drug approved for human use and with a known clinical profile, was recently shown to be an inhibitor of angiogenesis in vitro and exhibited tumor growth inhibition in mice. Here we describe the synthesis and in vitro evaluation of a series of N-alkylated analogues of levamisole with the aim of characterizing structure-activity relationships with regard to inhibition of angiogenesis. N-methyllevamisole and p-bromolevamisole proved more effective than the parent compound, (S)-levamisole hydrochloride, with respect to inhibition of angiogenesis and induction of undifferentiated cluster morphology in human umbilical vein endothelial cells grown in co-culture with normal human dermal fibroblasts. Interestingly, the cluster morphology caused by N-methyllevamisole was different than the clusters observed for levamisole, and a third "cord-like" morphology resembling that of the known drug suramin was observed for an aniline-containing derivative. New chemotypes exhibiting antiangiogenic effects in vitro are thus described, and further investigation of their underlying mechanism of action is warranted.

Novel levamisole derivative induces extrinsic pathway of apoptosis in cancer cells and inhibits tumor progression in mice.

BACKGROUND: Levamisole, an imidazo(2,1-b)thiazole derivative, has been reported to be a potential antitumor agent. In the present study, we have investigated the mechanism of action of one of the recently identified analogues, 4a (2-benzyl-6-(4'-fluorophenyl)-5-thiocyanato-imidazo[2,1-b][1], [3], [4]thiadiazole). MATERIALS AND METHODS: ROS production and expression of various apoptotic proteins were measured following 4a treatment in leukemia cell lines. Tumor animal models were used to evaluate the effect of 4a in comparison with Levamisole on progression of breast adenocarcinoma and survival. Immunohistochemistry and western blotting studies were performed to understand the mechanism of 4a action both ex vivo and in vivo. RESULTS: We have determined the IC(50) value of 4a in many leukemic and breast cancer cell lines and found CEM cells most sensitive (IC(50) 5 µM). Results showed that 4a treatment leads to the accumulation of ROS. Western blot analysis showed upregulation of pro-apoptotic proteins t-BID and BAX, upon treatment with 4a. Besides, dose-dependent activation of p53 along with FAS, FAS-L, and cleavage of CASPASE-8 suggest that it induces death receptor mediated apoptotic pathway in CEM cells. More importantly, we observed a reduction in tumor growth and significant increase in survival upon oral administration of 4a (20 mg/kg, six doses) in mice. In comparison, 4a was found to be more potent than its parental analogue Levamisole based on both ex vivo and in vivo studies. Further, immunohistochemistry and western blotting studies indicate that 4a treatment led to abrogation of tumor cell proliferation and activation of apoptosis by the extrinsic pathway even in animal models. CONCLUSION: Thus, our results suggest that 4a could be used as a potent chemotherapeutic agent.

Binding of [3H]m-aminolevamisole to receptors in levamisole-susceptible and -resistant Haemonchus contortus.

M-aminolevamisole, a potent analogue of the commercial anthelmintic levamisole, was used to investigate ligand-binding properties of homogenates of larval and parasitic stages of the nematode parasite of sheep, Haemonchus contortus. Kinetics of the binding of [3H]m-aminolevamisole to homogenates was measured in a drug-susceptible isolate and compared with a levamisole-resistant isolate. Equilibrium binding studies and kinetic studies revealed a high affinity binding component with a KD of 3 nM. A low affinity component (KD = 2.4 microM) was also apparent in equilibrium studies. High affinity [3H]m-aminolevamisole binding was displaced in a concentration-dependent manner by levamisole analogues and cholinergic agonists. Compared with the susceptible isolate, binding in a levamisole-resistant isolate of the parasite, was quantitatively similar over a range of developmental stages and binding conditions. However, under the conditions of binding there was a reduced affinity (larger KD) and more binding sites (larger Bmax) at the low affinity site in the resistant compared with the susceptible isolate. It was concluded that the ligand was binding to acetylcholine receptor populations of the nematode and that resistance may be associated with alterations in the low affinity site of this receptor.

Clinical and pharmacokinetic studies of high-dose levamisole in combination with 5-fluorouracil in patients with advanced cancer.

PURPOSE: To determine the maximum tolerable dose (MTD) and activity of levamisole administered concurrently with 5-fluorouracil (5-FU) in a standard 5-day course. To determine the pharmacokinetics of levamisole during the course of treatment. PATIENTS AND METHODS: Levamisole was administered to 38 patients orally three times a day for 5 days concurrently with a course of 5-FU administered daily by rapid intravenous injection for 5 days. Toxicity was evaluated in 20 patients who received escalating doses of levamisole. The activity of the combination was evaluated in 18 patients who received levamisole at the MTD with 5-FU. The pharmacokinetics of levamisole were characterized in ten patients at the MTD level. RESULTS: Intractable vomiting, confusion and vertigo were the major dose-limiting toxicities. The MTD of oral levamisole was 100 mg/m2 administered three times a day concurrently with 450 mg/m2 per day intravenous 5-FU for 5 consecutive days. Partial responses lasting 5 and 11 months were observed in 2/18 patients with measurable disease at the MTD. Peak plasma concentrations of 1 microg/ml (range 0.6-1.3 microg/ml) were achieved 90 min (range 60-360 min) after an oral dose of 100 mg/m2 levamisole with a 3.5-fold accumulation noted following 4 days of administration. Peak plasma concentrations of p-hydroxylevamisole were about 5% of parent drug. Little parent drug (2-5%) was detected in urine. CONCLUSIONS: Levamisole may be administered safely with 5-FU at doses which are up to four to five times greater than those presently given in conventional regimens. The recommended dose of levamisole combined with 5-FU for future research protocols is 75 mg/m2 t.i.d for 5 days.

Effect of IBMX and alkaline phosphatase inhibitors on Cl- secretion in G551D cystic fibrosis mutant mice.

Some cystic fibrosis transmembrane conductance regulator (CFTR) mutations, such as G551D, result in a correctly localized Cl- channel at the cell apical membrane, albeit with markedly reduced function. Patch-clamp studies have indicated that both phosphatase inhibitors and 3-isobutyl-1-methylxanthine (IBMX) can induce Cl- secretion through the G551D mutant protein. We have now assessed whether these agents can induce Cl- secretion in cftrG551D mutant mice. No induction of Cl- secretion was seen with the alkaline phosphatase inhibitors bromotetramisole or levamisole in either the respiratory or intestinal tracts of wild-type or cftrG551D mice. In contrast, in G551D intestinal tissues, IBMX was able to produce a small CFTR-related secretory response [means +/- SE: jejunum, 1.8 +/- 0.9 microA/cm2, n = 7; cecum, 3.7 +/- 0.8 microA/cm2, n = 7; rectum (in vivo), 1.9 +/- 0.9 mV, n = 5]. This was approximately one order of magnitude less than the wild-type response to this agent and, in the cecum, was significantly greater than that seen in null mice (cftrUNC). In the trachea, IBMX produced a transient Cl- secretory response (37.3 +/- 14.7 microA/cm2, n = 6) of a magnitude similar to that seen in wild-type mice (33.7 +/- 4.7 microA/cm2, n = 9). This response was also present in null mice and therefore is likely to be independent of CFTR. No effect of IBMX on Cl- secretion was seen in the nasal epithelium of cftrG551D mice. We conclude that IBMX is able to induce detectable levels of CFTR-related Cl- secretion in the intestinal tract but not the respiratory tract through the G551D mutant protein.

Stabilization of phospho-intermediates of rat liver plasma membrane alkaline phosphatase by uncompetitive inhibition. Relation with phosphate uptake into hepatocytes.

Rat liver plasma membrane alkaline phosphatase (ALP) phospho-intermediates, which have molecular masses of 151 and 135 kDa bands, were labelled at physiological pH with either (gamma-32P) ATP or 32Pi. This labeling was stabilized by a potent enzyme inhibitor, bromolevamisole (BL), and not by bromodexamisole (BD). BL augmented the rate and extent of autophosphorylation and slowed down the rate of autodephosphorylation of ALP. The phospho-intermediates labeling presented nearly the same kinetic behaviour with either (gamma-32P) ATP or 32Pi. In the presence of BL a marked decrease of the phosphorylation state of many proteins was observed in hepatocytes. BL also produced a decrease of the 32Pi uptake into hepatocytes and a decrease of the specific radioactivity of cellular ATP. BD had nearly the same effect as BL on protein phosphorylation and 32Pi uptake. These results argued against a direct involvement of ALP in Pi transport across hepatocyte plasma membrane.

Ultracytochemistry of enzymes in cell biology of the retina.

In matured chick retina, alkaline phosphatase activity is specifically localized in the outer plexiform layer and in the horizontal and Müller cells. In developing chick retina, the activity is recognized in growing neurites from horizontal cells, when synaptogenesis begins in the outer plexiform layer. Using levamisole, a potent inhibitor of alkaline phosphatase, on chick retina in vivo and in vitro, the enzyme was shown to play a significant role in retinal cell differentiation. 5'-Nucleotidase is used as a marker for the rod photoreceptors. It became apparent that the 'displaced' rod cells are localized in the inner nuclear layer of postnatal retina. High activity of glucose-6-phosphatase is confirmed in the cisternae of the smooth and rough endoplasmic reticulum, together with the space of the perinuclear envelope in the pigment epithelium of rat. The process of disc membrane recycling in the rod outer segment was investigated cytochemically to reveal sequential changes in lysosomal digestion both by conventional enzyme cytochemistry and by high voltage electron microscopy. With conventional enzyme histochemistry as well as with rapid freeze substitution enzyme cytochemistry, all enzyme for cGMP metabolism were observed to be on the cytoplasmic side of the disc membranes.

Synthesis and anthelmintic activity of 3'-benzoylurea derivatives of 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole.

Reaction of 3-amino derivatives of the nematocides tetramisole and levamisole with variously substituted benzoylisocyanates gave a series of benzoylureas I which were tested for activity against helminths and ectoparasites. Compounds bearing 2,6-difluoro and 4-trifluoromethyl substituents had potent nematocidal activity in both mice and sheep. No antiectoparasitic activity was observed.

Measurement of alkaline phosphatase of intestinal origin in plasma by p-bromotetramisole inhibition.

L-p-bromotetramisole was used to inhibit non-intestinal alkaline phosphatase (of liver or bone origin) (EC 3.1.3.1; ALP) in plasma, and intestinal ALP was measured from the uninhibited activity. The method of determination is convenient and correlated well with measurement by immunocapture assay. If carried out in parallel with wheat-germ lectin precipitation of bone ALP, subtraction of intestinal ALP activity from that of non-bone ALP in the supernatant can be used to measure the ALP that originates from the liver in men and non-pregnant women.

Utility of a Haemonchus contortus/jird (Meriones unguiculatus) model for studying resistance to levamisole.

Trichostrongylid nematodes of sheep commonly are identified as exhibiting resistance to levamisole. In vitro assays have been developed to study levamisole resistance for Haemonchus contortus, but no in vivo model has been identified for this species. To determine the utility of a H. contortus/jird (Meriones unguiculatus) model for examining levamisole resistance, immunosuppressed jirds were inoculated with approximately 1,000 exsheathed infective larvae of H. contortus (resistant or susceptible to levamisole), treated per os on day 10 postinoculation (PI) with levamisole hydrochloride or analogs of the drug, and killed on day 13 PI. Stomachs were removed, opened longitudinally, incubated in distilled water at 37 C for 5 hr, fixed in formaldehyde solution, and stored for subsequent microscopic examination. Doses of levamisole and its analogs, which elicited percentage clearances of greater than or equal to 93.5 for the susceptible strain, cleared less than or equal to 68.9% of the resistant worms. These data are consistent with activities for the drugs against wild-type and levamisole-resistant strains of Caenorhabditis elegans. Thus, the H. contortus/jird model provides a useful in vivo tool to study resistance to levamisole and possibly other anthelmintics.

Immunomodulatory action of levamisole--I. Structural analysis and immunomodulating activity of levamisole degradation products.

In our laboratory we observed that solutions of levamisole (LMS) stored at 4 degrees C consistently enhanced the lymphocyte proliferation response to concanavalin A (Con A) more than freshly prepared solutions did. To determine if the increased immunopotentiation observed with the stored solutions of LMS was due to products formed from LMS, we assessed the stability of LMS when stored at 4 or 37 degrees C at pH 6, 7, 7.5 and 8. Analysis of the various solutions by high pressure liquid chromatography demonstrated that LMS decomposes during storage in neutral and alkaline conditions to form three products. The formation of the products was accelerated by increasing the temperature from 4 to 37 degrees C. The three degradation products were purified by preparative high pressure liquid chromatography and their structures determined by mass spectrometry, infrared spectrometry and homo- and heteronuclear two dimensional nuclear magnetic resonance spectroscopy. The degradation products, denoted as No. 1, No. 2 and No. 3, based on their high pressure liquid chromatography retention times, were identified as: No. 1, 3-(2-mercaptoethyl)-5-phenylimidazolidine-2-one; No. 2, 6-phenyl-2,3-dihydroimidazo (2,1-b) thiazole and No. 3, bis [3-(2-oxo-5-phenylimidazolidin-1-yl) ethyl] disulfide. Product 2 significantly enhanced murine lymphocyte proliferation responses to concanavalin A (Con A) at concentrations between 0.5 and 10.0 micrograms/ml (whereas the optimum concentration of LMS is 10-100 fold higher (50-100 micrograms/ml)). Products 1, 2 and 3 significantly inhibited the lymphocyte proliferative response at concentrations greater than 2.2, 10.0 and 10.0 micrograms/ml, respectively. These studies indicate that under relatively mild conditions, including physiological conditions, LMS may decompose to products which inhibit or enhance lymphocyte responses to Con A.

Immunomodulatory action of levamisole--II. Enhancement of concanavalin A response by levamisole is associated with an oxidation degradation product of levamisole formed during lymphocyte culture.

Previously we determined that levamisole (LMS), when stored for a period of time, breaks down to three degradation products at neutral and alkaline pH. At low concentrations (10(-6) M), Product 1 inhibits the lymphocyte response to concanavalin A (Con A). Product 2 enhances the response and Product 3 has no effect. At higher concentrations (10(-5) M) all three products inhibit the response. To determine if these products are formed in culture media under culture conditions (e.g. in RPMI-1640 bicarbonate buffered medium, 37 degrees C, pH 7.0-7.5, during a 72 h culture period), we added freshly prepared LMS solutions to culture media with and without lymphocytes present and maintained the pH at 7.0, 7.25 or 7.5 by varying the amount of CO2 present. Periodically over a 72 h period, aliquots of the media were removed and analyzed for the presence of LMS and the three degradation products. Within 4 h, two of the degradation product began to form in culture media with or without lymphocytes present. Product No. 1, 3-(2-mercaptoethyl)-5-phenylimidazolidine-2-one or dl-2-oxy-3-(2-mercaptoethyl)-5-phenylimidazolidine (OMPI), which inhibits the lymphocyte response to concanavalin A (Con A) at concentrations above 0.4 micrograms/ml, was formed at pH 7.0, 7.25 and 7.5, but the compound did not reach inhibitory concentrations in the lymphocyte cultures during the 72 h culture period. Product No. 2, 6-phenyl-2,3-dihydroimidazo (2,1-b) thiazole, which enhances the Con A response between concentrations of 0.5 and 10 micrograms/ml, was detected at concentrations between 2.5 and 3.5 micrograms/ml at pH 7.25 and 7.5. Product 2 was not detected in cultures at pH 7.0 and subsequently when we cultured lymphocytes with freshly prepared LMS and maintained the pH at 7.0, no significant enhancement of the Con A response was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug-protein interactions. Comparative studies of levamisole and structural analogs or agents with immunomodulatory effect on the mechanism of protein aggregation.

Interactions of tetramisole, imidazo[2,1-b]thiazolic derived or immunomodulatory agents with human serum albumin (HSA) and immunoglobulins G and A has been investigated in vitro using polyacrylamide gel electrophoresis and immunoelectrophoresis. The results suggest that only the chemical structure type of tetramisole is able to induce a protein-protein interaction described as a mechanism of disulfide-sulfhydryl interchange reactions. The groups of atoms involved in the interaction are characterized.